A multisession evaluation of an adaptive competitive arm rehabilitation game.

PubMed

Goršič, Maja; Cikajlo, Imre; Goljar, Nika; Novak, Domen

2017-12-06

People with neurological injuries such as stroke should exercise frequently and intensely to regain their motor abilities, but are generally hindered by lack of motivation. One way to increase motivation in rehabilitation is through competitive exercises, but such exercises have only been tested in single brief sessions and usually did not adapt difficulty to the patient's abilities. We designed a competitive arm rehabilitation game for two players that dynamically adapts its difficulty to both players' abilities. This game was evaluated by two participant groups: 15 participants with chronic arm impairment who exercised at home with an unimpaired friend or relative, and 20 participants in the acute or subacute phase of stroke who exercised in pairs (10 pairs) at a rehabilitation clinic. All participants first played the game against their human opponent for 3 sessions, then played alone (against a computer opponent) in the final, fourth session. In all sessions, participants' subjective experiences were assessed with the Intrinsic Motivation Inventory questionnaire while exercise intensity was measured using inertial sensors built into the rehabilitation device. After the fourth session, a final brief questionnaire was used to compare competition and exercising alone. Participants who played against an unimpaired friend or relative at home tended to prefer competition (only 1 preferred exercising alone), and exhibited higher enjoyment and exercise intensity when competing (first three sessions) than when exercising alone (last session). Participants who played against each other in the clinic, however, did not exhibit significant differences between competition and exercising alone. For both groups, there was no difference in enjoyment or exercise intensity between the first three sessions, indicating no negative effects of habituation or novelty. Competitive exercises have high potential for unsupervised home rehabilitation, as they improve enjoyment and exercise intensity compared to exercising alone. Such exercises could thus improve rehabilitation outcome, but this needs to be tested in long-term clinical trials. It is not clear why participants who competed against each other at the clinic did not exhibit any advantages of competition, and further studies are needed to determine how different factors (environment, nature of opponent etc.) influence patients' experiences with competitive exercises. The study is not a clinical trial. While human subjects are involved, they do not participate in a full rehabilitation intervention, and no health outcomes are examined.

Six weeks of a polarized training-intensity distribution leads to greater physiological and performance adaptations than a threshold model in trained cyclists.

PubMed

Neal, Craig M; Hunter, Angus M; Brennan, Lorraine; O'Sullivan, Aifric; Hamilton, D Lee; De Vito, Giuseppe; Galloway, Stuart D R

2013-02-15

This study was undertaken to investigate physiological adaptation with two endurance-training periods differing in intensity distribution. In a randomized crossover fashion, separated by 4 wk of detraining, 12 male cyclists completed two 6-wk training periods: 1) a polarized model [6.4 (±1.4 SD) h/wk; 80%, 0%, and 20% of training time in low-, moderate-, and high-intensity zones, respectively]; and 2) a threshold model [7.5 (±2.0 SD) h/wk; 57%, 43%, and 0% training-intensity distribution]. Before and after each training period, following 2 days of diet and exercise control, fasted skeletal muscle biopsies were obtained for mitochondrial enzyme activity and monocarboxylate transporter (MCT) 1 and 4 expression, and morning first-void urine samples were collected for NMR spectroscopy-based metabolomics analysis. Endurance performance (40-km time trial), incremental exercise, peak power output (PPO), and high-intensity exercise capacity (95% maximal work rate to exhaustion) were also assessed. Endurance performance, PPOs, lactate threshold (LT), MCT4, and high-intensity exercise capacity all increased over both training periods. Improvements were greater following polarized rather than threshold for PPO [mean (±SE) change of 8 (±2)% vs. 3 (±1)%, P < 0.05], LT [9 (±3)% vs. 2 (±4)%, P < 0.05], and high-intensity exercise capacity [85 (±14)% vs. 37 (±14)%, P < 0.05]. No changes in mitochondrial enzyme activities or MCT1 were observed following training. A significant multilevel, partial least squares-discriminant analysis model was obtained for the threshold model but not the polarized model in the metabolomics analysis. A polarized training distribution results in greater systemic adaptation over 6 wk in already well-trained cyclists. Markers of muscle metabolic adaptation are largely unchanged, but metabolomics markers suggest different cellular metabolic stress that requires further investigation.

Novel, high-intensity exercise prescription improves muscle mass, mitochondrial function, and physical capacity in individuals with Parkinson's disease

PubMed Central

Kelly, Neil A.; Ford, Matthew P.; Standaert, David G.; Watts, Ray L.; Bickel, C. Scott; Moellering, Douglas R.; Tuggle, S. Craig; Williams, Jeri Y.; Lieb, Laura; Windham, Samuel T.

2014-01-01

We conducted, in persons with Parkinson's disease (PD), a thorough assessment of neuromotor function and performance in conjunction with phenotypic analyses of skeletal muscle tissue, and further tested the adaptability of PD muscle to high-intensity exercise training. Fifteen participants with PD (Hoehn and Yahr stage 2–3) completed 16 wk of high-intensity exercise training designed to simultaneously challenge strength, power, endurance, balance, and mobility function. Skeletal muscle adaptations (P < 0.05) to exercise training in PD included myofiber hypertrophy (type I: +14%, type II: +36%), shift to less fatigable myofiber type profile, and increased mitochondrial complex activity in both subsarcolemmal and intermyofibrillar fractions (I: +45–56%, IV: +39–54%). These adaptations were accompanied by a host of functional and clinical improvements (P < 0.05): total body strength (+30–56%); leg power (+42%); single leg balance (+34%); sit-to-stand motor unit activation requirement (−30%); 6-min walk (+43 m), Parkinson's Disease Quality of Life Scale (PDQ-39, −7.8pts); Unified Parkinson's Disease Rating Scale (UPDRS) total (−5.7 pts) and motor (−2.7 pts); and fatigue severity (−17%). Additionally, PD subjects in the pretraining state were compared with a group of matched, non-PD controls (CON; did not exercise). A combined assessment of muscle tissue phenotype and neuromuscular function revealed a higher distribution and larger cross-sectional area of type I myofibers and greater type II myofiber size heterogeneity in PD vs. CON (P < 0.05). In conclusion, persons with moderately advanced PD adapt to high-intensity exercise training with favorable changes in skeletal muscle at the cellular and subcellular levels that are associated with improvements in motor function, physical capacity, and fatigue perception. PMID:24408997

Influence of dietary nitrate supplementation on physiological and muscle metabolic adaptations to sprint interval training

PubMed Central

Thompson, Christopher; Wylie, Lee J.; Blackwell, Jamie R.; Fulford, Jonathan; Black, Matthew I.; Kelly, James; McDonagh, Sinead T. J.; Carter, James; Bailey, Stephen J.; Vanhatalo, Anni

2017-01-01

We hypothesized that 4 wk of dietary nitrate supplementation would enhance exercise performance and muscle metabolic adaptations to sprint interval training (SIT). Thirty-six recreationally active subjects, matched on key variables at baseline, completed a series of exercise tests before and following a 4-wk period in which they were allocated to one of the following groups: 1) SIT and NO3−-depleted beetroot juice as a placebo (SIT+PL); 2) SIT and NO3−-rich beetroot juice (~13 mmol NO3−/day; SIT+BR); or 3) no training and NO3−-rich beetroot juice (NT+BR). During moderate-intensity exercise, pulmonary oxygen uptake was reduced by 4% following 4 wk of SIT+BR and NT+BR (P < 0.05) but not SIT+PL. The peak work rate attained during incremental exercise increased more in SIT+BR than in SIT+PL (P < 0.05) or NT+BR (P < 0.001). The reduction in muscle and blood [lactate] and the increase in muscle pH from preintervention to postintervention were greater at 3 min of severe-intensity exercise in SIT+BR compared with SIT+PL and NT+BR (P < 0.05). However, the change in severe-intensity exercise performance was not different between SIT+BR and SIT+PL (P > 0.05). The relative proportion of type IIx muscle fibers in the vastus lateralis muscle was reduced in SIT+BR only (P < 0.05). These findings suggest that BR supplementation may enhance some aspects of the physiological adaptations to SIT. NEW & NOTEWORTHY We investigated the influence of nitrate-rich and nitrate-depleted beetroot juice on the muscle metabolic and physiological adaptations to 4 wk of sprint interval training. Compared with placebo, dietary nitrate supplementation reduced the O2 cost of submaximal exercise, resulted in greater improvement in incremental (but not severe-intensity) exercise performance, and augmented some muscle metabolic adaptations to training. Nitrate supplementation may facilitate some of the physiological responses to sprint interval training. PMID:27909231

Role of metabolic stress for enhancing muscle adaptations: Practical applications

PubMed Central

de Freitas, Marcelo Conrado; Gerosa-Neto, Jose; Zanchi, Nelo Eidy; Lira, Fabio Santos; Rossi, Fabrício Eduardo

2017-01-01

Metabolic stress is a physiological process that occurs during exercise in response to low energy that leads to metabolite accumulation [lactate, phosphate inorganic (Pi) and ions of hydrogen (H+)] in muscle cells. Traditional exercise protocol (i.e., Resistance training) has an important impact on the increase of metabolite accumulation, which influences hormonal release, hypoxia, reactive oxygen species (ROS) production and cell swelling. Changes in acute exercise routines, such as intensity, volume and rest between sets, are determinants for the magnitude of metabolic stress, furthermore, different types of training, such as low-intensity resistance training plus blood flow restriction and high intensity interval training, could be used to maximize metabolic stress during exercise. Thus, the objective of this review is to describe practical applications that induce metabolic stress and the potential effects of metabolic stress to increase systemic hormonal release, hypoxia, ROS production, cell swelling and muscle adaptations. PMID:28706859

Importance of exercise immunology in health promotion.

PubMed

Neto, J C Rosa; Lira, F S; de Mello, M T; Santos, Ronaldo Vagner T

2011-11-01

Chronic physical exercise with adequate intensity and volume associated with sufficient recovery promotes adaptations in several physiological systems. While intense and exhaustive exercise is considered an important immunosuppressor agent and increases the incidence of upper respiratory tract infections (URTI), moderate regular exercise has been associated with significant disease protection and is a complementary treatment of many chronic diseases. The effects of chronic exercise occur because physical training can induce several physiological, biochemical and psychological adaptations. More recently, the effect of acute exercise and training on the immunological system has been discussed, and many studies suggest the importance of the immune system in prevention and partial recovery in pathophysiological situations. Currently, there are two important hypotheses that may explain the effects of exercise and training on the immune system. These hypotheses including (1) the effect of exercise upon hormones and cytokines (2) because exercise can modulate glutamine concentration. In this review, we discuss the hypothesis that exercise may modulate immune functions and the importance of exercise immunology in respect to chronic illnesses, chronic heart failure, malnutrition and inflammation.

The Effect of Music on Exercise Intensity among Children with Autism Spectrum Disorder: A Pilot Study

PubMed Central

Woodman, Ashley C.; Breviglia, Emily; Mori, Yumiko; Golden, Rebecca; Maina, John; Wisniewski, Hannah

2018-01-01

Children with autism spectrum disorder (ASD) are at risk for obesity, commonly have sleep disorders, and exhibit stereotypic behaviors that disrupt their learning. Vigorous levels of exercise have been shown to ameliorate these issues in children with ASD, but little research exists to provide techniques for motivating children with ASD to engage in exercise. The present study examined the effect of music on exercise intensity in a group of 13 elementary school students with ASD. Data were collected across six days during structured (e.g., verbal and physical prompts) and unstructured (e.g., minimal prompting) exercise periods. During these exercise periods, three music conditions were randomized: no music, slow-tempo music, and fast-tempo music. Exercise intensity, measured in Metabolic Equivalent of Tasks by triaxial accelerometers, was greatest during the structured exercise periods and during the slow music condition. Student characteristics moderated the impact of music condition on exercise intensity, such that students with high levels of adaptive behavior or lower levels of maladaptive behavior displayed greater exercise intensity during the fast music condition. PMID:29495354

Exercise intensity and muscle hypertrophy in blood flow-restricted limbs and non-restricted muscles: a brief review.

PubMed

Abe, Takashi; Loenneke, Jeremy P; Fahs, Christopher A; Rossow, Lindy M; Thiebaud, Robert S; Bemben, Michael G

2012-07-01

Although evidence for high-intensity resistance training-induced muscle hypertrophy has accumulated over the last several decades, the basic concept of the training can be traced back to ancient Greece: Milo of Croton lifted a bull-calf daily until it was fully grown, which would be known today as progressive overload. Now, in the 21st century, different types of training are being tested and studied, such as low-intensity exercise combined with arterial as well as venous blood flow restriction (BFR) to/from the working muscles. Because BFR training requires the use of a cuff that is placed at the proximal ends of the arms and/or legs, the BFR is only applicable to limb muscles. Consequently, most previous BFR training studies have focused on the physiological adaptations of BFR limb muscles. Muscle adaptations in non-BFR muscles of the hip and trunk are lesser known. Recent studies that have reported both limb and trunk muscle adaptations following BFR exercise training suggest that low-intensity (20-30% of 1RM) resistance training combined with BFR elicits muscle hypertrophy in both BFR limb and non-BFR muscles. However, the combination of leg muscle BFR with walk training elicits muscle hypertrophy only in the BFR leg muscles. In contrast to resistance exercise with BFR, the exercise intensity may be too low during BFR walk training to cause muscle hypertrophy in the non-BFR gluteus maximus and other trunk muscles. Other mechanisms including hypoxia, local and systemic growth factors and muscle cell swelling may also potentially affect the hypertrophic response of non-BFR muscles to BFR resistance exercise. © 2012 The Authors Clinical Physiology and Functional Imaging © 2012 Scandinavian Society of Clinical Physiology and Nuclear Medicine.

Does exercise motivation predict engagement in objectively assessed bouts of moderate-intensity exercise? A self-determination theory perspective.

PubMed

Standage, Martyn; Sebire, Simon J; Loney, Tom

2008-08-01

This study examined the utility of motivation as advanced by self-determination theory (Deci & Ryan, 2000) in predicting objectively assessed bouts of moderate intensity exercise behavior. Participants provided data pertaining to their exercise motivation. One week later, participants wore a combined accelerometer and heart rate monitor (Actiheart; Cambridge Neurotechnology Ltd) and 24-hr energy expenditure was estimated for 7 days. After controlling for gender and a combined marker of BMI and waist circumference, results showed autonomous motivation to positively predict moderate-intensity exercise bouts of >or=10 min, or=20 min, and an accumulation needed to meet public health recommendations for moderate intensity activity (i.e., ACSM/AHA guidelines). The present findings add bouts of objectively assessed exercise behavior to the growing body of literature that documents the adaptive consequences of engaging in exercise for autonomous reasons. Implications for practice and future work are discussed.

Military Applicability of Interval Training for Health and Performance.

PubMed

Gibala, Martin J; Gagnon, Patrick J; Nindl, Bradley C

2015-11-01

Militaries from around the globe have predominantly used endurance training as their primary mode of aerobic physical conditioning, with historical emphasis placed on the long distance run. In contrast to this traditional exercise approach to training, interval training is characterized by brief, intermittent bouts of intense exercise, separated by periods of lower intensity exercise or rest for recovery. Although hardly a novel concept, research over the past decade has shed new light on the potency of interval training to elicit physiological adaptations in a time-efficient manner. This work has largely focused on the benefits of low-volume interval training, which involves a relatively small total amount of exercise, as compared with the traditional high-volume approach to training historically favored by militaries. Studies that have directly compared interval and moderate-intensity continuous training have shown similar improvements in cardiorespiratory fitness and the capacity for aerobic energy metabolism, despite large differences in total exercise and training time commitment. Interval training can also be applied in a calisthenics manner to improve cardiorespiratory fitness and strength, and this approach could easily be incorporated into a military conditioning environment. Although interval training can elicit physiological changes in men and women, the potential for sex-specific adaptations in the adaptive response to interval training warrants further investigation. Additional work is needed to clarify adaptations occurring over the longer term; however, interval training deserves consideration from a military applicability standpoint as a time-efficient training strategy to enhance soldier health and performance. There is value for military leaders in identifying strategies that reduce the time required for exercise, but nonetheless provide an effective training stimulus.

High-intensity interval exercise and cerebrovascular health: curiosity, cause, and consequence

PubMed Central

Lucas, Samuel J E; Cotter, James D; Brassard, Patrice; Bailey, Damian M

2015-01-01

Exercise is a uniquely effective and pluripotent medicine against several noncommunicable diseases of westernised lifestyles, including protection against neurodegenerative disorders. High-intensity interval exercise training (HIT) is emerging as an effective alternative to current health-related exercise guidelines. Compared with traditional moderate-intensity continuous exercise training, HIT confers equivalent if not indeed superior metabolic, cardiac, and systemic vascular adaptation. Consequently, HIT is being promoted as a more time-efficient and practical approach to optimize health thereby reducing the burden of disease associated with physical inactivity. However, no studies to date have examined the impact of HIT on the cerebrovasculature and corresponding implications for cognitive function. This review critiques the implications of HIT for cerebrovascular function, with a focus on the mechanisms and translational impact for patient health and well-being. It also introduces similarly novel interventions currently under investigation as alternative means of accelerating exercise-induced cerebrovascular adaptation. We highlight a need for studies of the mechanisms and thereby also the optimal dose-response strategies to guide exercise prescription, and for studies to explore alternative approaches to optimize exercise outcomes in brain-related health and disease prevention. From a clinical perspective, interventions that selectively target the aging brain have the potential to prevent stroke and associated neurovascular diseases. PMID:25833341

High-intensity interval exercise and cerebrovascular health: curiosity, cause, and consequence.

PubMed

Lucas, Samuel J E; Cotter, James D; Brassard, Patrice; Bailey, Damian M

2015-06-01

Exercise is a uniquely effective and pluripotent medicine against several noncommunicable diseases of westernised lifestyles, including protection against neurodegenerative disorders. High-intensity interval exercise training (HIT) is emerging as an effective alternative to current health-related exercise guidelines. Compared with traditional moderate-intensity continuous exercise training, HIT confers equivalent if not indeed superior metabolic, cardiac, and systemic vascular adaptation. Consequently, HIT is being promoted as a more time-efficient and practical approach to optimize health thereby reducing the burden of disease associated with physical inactivity. However, no studies to date have examined the impact of HIT on the cerebrovasculature and corresponding implications for cognitive function. This review critiques the implications of HIT for cerebrovascular function, with a focus on the mechanisms and translational impact for patient health and well-being. It also introduces similarly novel interventions currently under investigation as alternative means of accelerating exercise-induced cerebrovascular adaptation. We highlight a need for studies of the mechanisms and thereby also the optimal dose-response strategies to guide exercise prescription, and for studies to explore alternative approaches to optimize exercise outcomes in brain-related health and disease prevention. From a clinical perspective, interventions that selectively target the aging brain have the potential to prevent stroke and associated neurovascular diseases.

Longitudinal social cognitive influences on physical activity and sedentary time in Hispanic breast cancer survivors

PubMed Central

Mama, Scherezade K.; Song, Jaejoon; Ortiz, Alexis; Tirado-Gomez, Maribel; Palacios, Cristina; Hughes, Daniel C.; Basen-Engquist, Karen

2016-01-01

Objective This study evaluated the effect of two home-based exercise interventions (one culturally-adapted and one standard) on changes in Social Cognitive Theory (SCT) variables, physical activity (PA) and sedentary time (ST), and to determine the association between changes in SCT variables and changes in PA and ST in Hispanic breast cancer survivors. Method Project VIVA! was a 16-week randomized controlled pilot study to test the effectiveness and feasibility of a culturally-adapted exercise intervention for Mexican American and Puerto Rican breast cancer survivors in Houston, Texas and San Juan, Puerto Rico, respectively. Women (N=89) completed questionnaires on SCT variables, PA and ST and were then randomized to a 16-week culturally-adapted exercise program, a non-culturally adapted standard exercise intervention or a wait-list control group. Multiple regression models were used to determine associations between changes in SCT variables and changes in PA and ST. Results Participants were in their late 50s (58.5 ± 9.2 years) and obese (31.0 ± 6.5 kg/m2). Women reported doing roughly 34.5 minutes/day of PA and spending over 11 hours/day in sedentary activities. Across groups, women reported significant increases in exercise self-efficacy and moderate-intensity, vigorous-intensity, and total physical activity from baseline to follow-up (p<.05). Increased social support from family was associated with increases in vigorous-intensity PA. Increases in social modeling were associated with increases in moderate-intensity and total PA and decreases in ST from baseline to follow-up (p<.05). Conclusions Hispanic cancer survivors benefit from PA interventions that focus on increasing social support from family and friends and social modeling. PMID:26602701

The role of oxidative, inflammatory and neuroendocrinological systems during exercise stress in athletes: implications of antioxidant supplementation on physiological adaptation during intensified physical training.

PubMed

Slattery, Katie; Bentley, David; Coutts, Aaron J

2015-04-01

During periods of intensified physical training, reactive oxygen species (ROS) release may exceed the protective capacity of the antioxidant system and lead to dysregulation within the inflammatory and neuroendocrinological systems. Consequently, the efficacy of exogenous antioxidant supplementation to maintain the oxidative balance in states of exercise stress has been widely investigated. The aim of this review was to (1) collate the findings of prior research on the effect of intensive physical training on oxidant-antioxidant balance; (2) summarise the influence of antioxidant supplementation on the reduction-oxidation signalling pathways involved in physiological adaptation; and (3) provide a synopsis on the interactions between the oxidative, inflammatory and neuroendocrinological response to exercise stimuli. Based on prior research, it is evident that ROS are an underlying aetiology in the adaptive process; however, the impact of antioxidant supplementation on physiological adaptation remains unclear. Equivocal results have been reported on the impact of antioxidant supplementation on exercise-induced gene expression. Further research is required to establish whether the interference of antioxidant supplementation consistently observed in animal-based and in vivo research extends to a practical sports setting. Moreover, the varied results reported within the literature may be due to the hormetic response of oxidative, inflammatory and neuroendocrinological systems to an exercise stimulus. The collective findings suggest that intensified physical training places substantial stress on the body, which can manifest as an adaptive or maladaptive physiological response. Additional research is required to determine the efficacy of antioxidant supplementation to minimise exercise-stress during intensive training and promote an adaptive state.

Basic science behind the cardiovascular benefits of exercise.

PubMed

Wilson, Mathew G; Ellison, Georgina M; Cable, N Tim

2015-12-01

Cardiorespiratory fitness is a strong predictor of cardiovascular (CV) disease and all-cause mortality, with increases in cardiorespiratory fitness associated with corresponding decreases in CV disease risk. The effects of exercise upon the myocardium and vascular system are dependent upon the frequency, intensity and duration of the exercise itself. Following a prolonged period (≥ 6 months) of regular intensive exercise in previously untrained individuals, resting and submaximal exercising heart rates are typically 5-20 beats lower, with an increase in stroke volume of ∼ 20% and enhanced myocardial contractility. Structurally, all four heart chambers increase in volume with mild increases in wall thickness, resulting in greater cardiac mass due to increased myocardial cell size. With this in mind, the present paper aims to review the basic science behind the CV benefits of exercise. Attention will be paid to understanding (1) the relationship between exercise and cardiac remodelling; (2) the cardiac cellular and molecular adaptations in response to exercise, including the examination of molecular mechanisms of physiological cardiac growth and applying these mechanisms to identify new therapeutic targets to prevent or reverse pathological remodelling and heart failure; and (3) vascular adaptations in response to exercise. Finally, this review will briefly examine how to optimise the CV benefits of exercise by considering how much and how intense exercise should be. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Basic science behind the cardiovascular benefits of exercise.

PubMed

Wilson, Mathew G; Ellison, Georgina M; Cable, N Tim

2015-05-15

Cardiorespiratory fitness is a strong predictor of cardiovascular (CV) disease and all-cause mortality, with increases in cardiorespiratory fitness associated with corresponding decreases in CV disease risk. The effects of exercise upon the myocardium and vascular system are dependent upon the frequency, intensity and duration of the exercise itself. Following a prolonged period (≥6 months) of regular intensive exercise in previously untrained individuals, resting and submaximal exercising heart rates are typically 5-20 beats lower, with an increase in stroke volume of ∼20% and enhanced myocardial contractility. Structurally, all four heart chambers increase in volume with mild increases in wall thickness, resulting in greater cardiac mass due to increased myocardial cell size. With this in mind, the present paper aims to review the basic science behind the CV benefits of exercise. Attention will be paid to understanding (1) the relationship between exercise and cardiac remodelling; (2) the cardiac cellular and molecular adaptations in response to exercise, including the examination of molecular mechanisms of physiological cardiac growth and applying these mechanisms to identify new therapeutic targets to prevent or reverse pathological remodelling and heart failure; and (3) vascular adaptations in response to exercise. Finally, this review will briefly examine how to optimise the CV benefits of exercise by considering how much and how intense exercise should be. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Basic science behind the cardiovascular benefits of exercise.

PubMed

Wilson, Mathew G; Ellison, Georgina M; Cable, N Tim

2016-01-01

Cardiorespiratory fitness is a strong predictor of cardiovascular (CV) disease and all-cause mortality, with increases in cardiorespiratory fitness associated with corresponding decreases in CV disease risk. The effects of exercise upon the myocardium and vascular system are dependent upon the frequency, intensity and duration of the exercise itself. Following a prolonged period (≥6 months) of regular intensive exercise in previously untrained individuals, resting and submaximal exercising heart rates are typically 5-20 beats lower, with an increase in stroke volume of ∼20% and enhanced myocardial contractility. Structurally, all four heart chambers increase in volume with mild increases in wall thickness, resulting in greater cardiac mass due to increased myocardial cell size. With this in mind, the present paper aims to review the basic science behind the CV benefits of exercise. Attention will be paid to understanding (1) the relationship between exercise and cardiac remodelling; (2) the cardiac cellular and molecular adaptations in response to exercise, including the examination of molecular mechanisms of physiological cardiac growth and applying these mechanisms to identify new therapeutic targets to prevent or reverse pathological remodelling and heart failure; and (3) vascular adaptations in response to exercise. Finally, this review will briefly examine how to optimise the CV benefits of exercise by considering how much and how intense exercise should be. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

The anaerobic threshold: over-valued or under-utilized? A novel concept to enhance lipid optimization!

PubMed

Connolly, Declan A J

2012-09-01

The purpose of this article is to assess the value of the anaerobic threshold for use in clinical populations with the intent to improve exercise adaptations and outcomes. The anaerobic threshold is generally poorly understood, improperly used, and poorly measured. It is rarely used in clinical settings and often reserved for athletic performance testing. Increased exercise participation within both clinical and other less healthy populations has increased our attention to optimizing exercise outcomes. Of particular interest is the optimization of lipid metabolism during exercise in order to improve numerous conditions such as blood lipid profile, insulin sensitivity and secretion, and weight loss. Numerous authors report on the benefits of appropriate exercise intensity in optimizing outcomes even though regulation of intensity has proved difficult for many. Despite limited use, selected exercise physiology markers have considerable merit in exercise-intensity regulation. The anaerobic threshold, and other markers such as heart rate, may well provide a simple and valuable mechanism for regulating exercising intensity. The use of the anaerobic threshold and accurate target heart rate to regulate exercise intensity is a valuable approach that is under-utilized across populations. The measurement of the anaerobic threshold can be simplified to allow clients to use nonlaboratory measures, for example heart rate, in order to self-regulate exercise intensity and improve outcomes.

Atypical blood glucose response to continuous and interval exercise in a person with type 1 diabetes: a case report.

PubMed

Moser, Othmar; Tschakert, Gerhard; Mueller, Alexander; Groeschl, Werner; Pieber, Thomas R; Koehler, Gerd; Eckstein, Max L; Bracken, Richard M; Hofmann, Peter

2017-06-30

Therapy must be adapted for people with type 1 diabetes to avoid exercise-induced hypoglycemia caused by increased exercise-related glucose uptake into muscles. Therefore, to avoid hypoglycemia, the preexercise short-acting insulin dose must be reduced for safety reasons. We report a case of a man with long-lasting type 1 diabetes in whom no blood glucose decrease during different types of exercise with varying exercise intensities and modes was found, despite physiological hormone responses. A Caucasian man diagnosed with type 1 diabetes for 24 years performed three different continuous high-intensity interval cycle ergometer exercises as part of a clinical trial (ClinicalTrials.gov identifier NCT02075567). Intensities for both modes of exercises were set at 5% below and 5% above the first lactate turn point and 5% below the second lactate turn point. Short-acting insulin doses were reduced by 25%, 50%, and 75%, respectively. Measurements taken included blood glucose, blood lactate, gas exchange, heart rate, adrenaline, noradrenaline, cortisol, glucagon, and insulin-like growth factor-1. Unexpectedly, no significant blood glucose decreases were observed during all exercise sessions (start versus end, 12.97 ± 2.12 versus 12.61 ± 2.66 mmol L -1 , p = 0.259). All hormones showed the expected response, dependent on the different intensities and modes of exercises. People with type 1 diabetes typically experience a decrease in blood glucose levels, particularly during low- and moderate-intensity exercises. In our patient, we clearly found no decline in blood glucose, despite a normal hormone response and no history of any insulin insensitivity. This report indicates that there might be patients for whom the recommended preexercise therapy adaptation to avoid exercise-induced hypoglycemia needs to be questioned because this could increase the risk of severe hyperglycemia and ketosis.

Effect of lemon verbena supplementation on muscular damage markers, proinflammatory cytokines release and neutrophils' oxidative stress in chronic exercise.

PubMed

Funes, Lorena; Carrera-Quintanar, Lucrecia; Cerdán-Calero, Manuela; Ferrer, Miguel D; Drobnic, Franchek; Pons, Antoni; Roche, Enrique; Micol, Vicente

2011-04-01

Intense exercise is directly related to muscular damage and oxidative stress due to excessive reactive oxygen species (ROS) in both, plasma and white blood cells. Nevertheless, exercise-derived ROS are essential to regulate cellular adaptation to exercise. Studies on antioxidant supplements have provided controversial results. The purpose of this study was to determine the effect of moderate antioxidant supplementation (lemon verbena extract) in healthy male volunteers that followed a 90-min running eccentric exercise protocol for 21 days. Antioxidant enzymes activities and oxidative stress markers were measured in neutrophils. Besides, inflammatory cytokines and muscular damage were determined in whole blood and serum samples, respectively. Intense running exercise for 21 days induced antioxidant response in neutrophils of trained male through the increase of the antioxidant enzymes catalase, glutathione peroxidase and glutathione reductase. Supplementation with moderate levels of an antioxidant lemon verbena extract did not block this cellular adaptive response and also reduced exercise-induced oxidative damage of proteins and lipids in neutrophils and decreased myeloperoxidase activity. Moreover, lemon verbena supplementation maintained or decreased the level of serum transaminases activity indicating a protection of muscular tissue. Exercise induced a decrease of interleukin-6 and interleukin-1β levels after 21 days measured in basal conditions, which was not inhibited by antioxidant supplementation. Therefore, moderate antioxidant supplementation with lemon verbena extract protects neutrophils against oxidative damage, decreases the signs of muscular damage in chronic running exercise without blocking the cellular adaptation to exercise.

Efficacy and feasibility of a novel tri-modal robust exercise prescription in a retirement community: a randomized, controlled trial.

PubMed

Baker, Michael K; Kennedy, David J; Bohle, Philip L; Campbell, Deena S; Knapman, Leona; Grady, Jodie; Wiltshire, James; McNamara, Maria; Evans, William J; Atlantis, Evan; Fiatarone Singh, Maria A

2007-01-01

To test the feasibility and efficacy of current guidelines for multimodal exercise programs in older adults. Randomized, controlled trial. Retirement village. Thirty-eight subjects (14 men and 24 women) aged 76.6 +/- 6.1. A wait list control or 10 weeks of supervised exercise consisting of high-intensity (80% of one-repetition maximum (1RM)) progressive resistance training (PRT) 3 days per week, moderate-intensity (rating of perceived exertion 11 to 14/20) aerobic training 2 days per week, and progressive balance training 1 day per week. Blinded assessments of dynamic muscle strength (1RM), balance, 6-minute walk, gait velocity, chair stand, stair climb, depressive symptoms, self-efficacy, and habitual physical activity level. Higher baseline strength and psychological well-being were associated with better functional performance. Strength gains over 10 weeks averaged 39+/-31% in exercise, versus 21+/-24% in controls (P=.10), with greater improvements in hip flexion (P=.01), hip abduction (P=.02), and chest press (P=.04) in the exercise group. Strength adaptations were greatest in exercises in which the intended continuous progressive overload was achieved. Stair climb power (12.3+/-15%, P=.002) and chair stand time (-7.1+/-15%, P=.006) improved significantly and similarly in both groups. Reduction in depressive symptoms was significantly related to compliance (attendance rate r=-0.568, P=.009, PRT progression in loading r=-0.587, P=.02, and total volume of aerobic training r=-0.541, P=.01), as well as improvements in muscle strength (r=-0.498, P=.002). Robust physical and psychological adaptations to exercise are linked, although volumes and intensities of multiple exercise modalities sufficient to cause significant adaptation appear difficult to prescribe and adhere to simultaneously in older adults.

Aerobic exercise deconditioning and countermeasures during bed rest.

PubMed

Lee, Stuart M C; Moore, Alan D; Everett, Meghan E; Stenger, Michael B; Platts, Steven H

2010-01-01

Bed rest is a well-accepted model for spaceflight in which the physiologic adaptations, particularly in the cardiovascular system, are studied and potential countermeasures can be tested. Bed rest without countermeasures results in reduced aerobic capacity and altered submaximal exercise responses. Aerobic endurance and factors which may impact prolonged exercise, however, have not been well studied. The initial loss of aerobic capacity is rapid, occurring in parallel with the loss of plasma volume. Thereafter, the reduction in maximal aerobic capacity proceeds more slowly and is influenced by central and peripheral adaptation. Exercise capacity can be maintained during bed rest and may be improved during recovery with appropriate countermeasures. Plasma volume restoration, resistive exercise, orthostatic stress, aerobic exercise, and aerobic exercise plus orthostatic stress all have been tested with varying levels of success. However, the optimal combination of elements-exercise modality, intensity, duration, muscle groups exercised and frequency of aerobic exercise, orthostatic stress, and supplementary resistive or anaerobic exercise training-has not been systematically evaluated. Currently, frequent (at least 3 days per week) bouts of intense exercise (interval-style and near maximal) with orthostatic stress appears to be the most efficacious method to protect aerobic capacity during bed rest. Further refinement of protocols and countermeasure hardware may be necessary to insure the success of countermeasures in the unique environment of space.

Oxidative stress and inflammation: liver responses and adaptations to acute and regular exercise.

PubMed

Pillon Barcelos, Rômulo; Freire Royes, Luiz Fernando; Gonzalez-Gallego, Javier; Bresciani, Guilherme

2017-02-01

The liver is remarkably important during exercise outcomes due to its contribution to detoxification, synthesis, and release of biomolecules, and energy supply to the exercising muscles. Recently, liver has been also shown to play an important role in redox status and inflammatory modulation during exercise. However, while several studies have described the adaptations of skeletal muscles to acute and chronic exercise, hepatic changes are still scarcely investigated. Indeed, acute intense exercise challenges the liver with increased reactive oxygen species (ROS) and inflammation onset, whereas regular training induces hepatic antioxidant and anti-inflammatory improvements. Acute and regular exercise protocols in combination with antioxidant and anti-inflammatory supplementation have been also tested to verify hepatic adaptations to exercise. Although positive results have been reported in some acute models, several studies have shown an increased exercise-related stress upon liver. A similar trend has been observed during training: while synergistic effects of training and antioxidant/anti-inflammatory supplementations have been occasionally found, others reported a blunting of relevant adaptations to exercise, following the patterns described in skeletal muscles. This review discusses current data regarding liver responses and adaptation to acute and regular exercise protocols alone or combined with antioxidant and anti-inflammatory supplementation. The understanding of the mechanisms behind these modulations is of interest for both exercise-related health and performance outcomes.

Effect of single-session aerobic exercise with varying intensities on lipid peroxidation and muscle-damage markers in sedentary males.

PubMed

Moflehi, Daruosh; Kok, Lian-Yee; Tengku-Kamalden, Tengku-Fadilah; Amri, Saidon

2012-05-23

This study was conducted to evaluate the effect of the different intensity levels of single-session aerobic exercise on serum levels of lipid peroxidation and muscle damage markers in sedentary males. Fifty one sedentary healthy males aged 21.76±1.89 years were randomly divided into four groups, with one control (n=10) and three treatment groups that attended single-session aerobic exercise with low (n=14), moderate (n=14), and high (n=13) intensities. The serum levels of malondialdehyde (MDA) and creatine kinase (CK) were measured. Data analysis revealed a significant effect by the intensity levels of aerobic exercise on MDA (P=0.001) and CK (P=0.003) post-test when the participants in the treatment groups were compared with the control. When the intensity of aerobic exercise was increased, the amount of MDA and CK was also found to be increased. Single-session aerobic exercise can increase the amount of MDA and CK, suggesting that low intensity level of aerobic exercise should be utilized for more adaptation, and to prevent lipid peroxidation and muscle damage in sedentary males.

Cardiorespiratory fitness modulates the acute flow-mediated dilation response following high-intensity but not moderate-intensity exercise in elderly men.

PubMed

Bailey, Tom G; Perissiou, Maria; Windsor, Mark; Russell, Fraser; Golledge, Jonathan; Green, Daniel J; Askew, Christopher D

2017-05-01

Impaired endothelial function is observed with aging and in those with low cardiorespiratory fitness (V̇o 2peak ). Improvements in endothelial function with exercise training are somewhat dependent on the intensity of exercise. While the acute stimulus for this improvement is not completely understood, it may, in part, be due to the flow-mediated dilation (FMD) response to acute exercise. We examined the hypothesis that exercise intensity alters the brachial (systemic) FMD response in elderly men and is modulated by V̇o 2peak Forty-seven elderly men were stratified into lower (V̇o 2peak = 24.3 ± 2.9 ml·kg -1 ·min -1 ; n = 27) and higher fit groups (V̇o 2peak = 35.4 ± 5.5 ml·kg -1 ·min -1 ; n = 20) after a test of cycling peak power output (PPO). In randomized order, participants undertook moderate-intensity continuous exercise (MICE; 40% PPO) or high-intensity interval cycling exercise (HIIE; 70% PPO) or no-exercise control. Brachial FMD was assessed at rest and 10 and 60 min after exercise. FMD increased after MICE in both groups {increase of 0.86% [95% confidence interval (CI), 0.17-1.56], P = 0.01} and normalized after 60 min. In the lower fit group, FMD was reduced after HIIE [reduction of 0.85% (95% CI, 0.12-1.58), P = 0.02] and remained decreased at 60 min. In the higher fit group, FMD was unchanged immediately after HIIE and increased after 60 min [increase of 1.52% (95% CI, 0.41-2.62), P < 0.01, which was correlated with V̇o 2peak , r = 0.41; P < 0.01]. In the no-exercise control, FMD was reduced in both groups after 60 min ( P = 0.05). Exercise intensity alters the acute FMD response in elderly men and V̇o 2peak modulates the FMD response following HIIE but not MICE. The sustained decrease in FMD in the lower fit group following HIIE may represent a signal for vascular adaptation or endothelial fatigue. NEW & NOTEWORTHY This study is the first to show that moderate-intensity continuous cycling exercise increased flow-mediated dilation (FMD) transiently before normalization of FMD after 1 h, irrespective of cardiorespiratory fitness level in elderly men. Interestingly, we show increased FMD after high-intensity cycling exercise in higher fit men, with a sustained reduction in FMD in lower fit men. The prolonged reduction in FMD after high-intensity cycling exercise may be associated with future vascular adaptation but may also reflect a period of increased cardiovascular risk in lower fit elderly men. Copyright © 2017 the American Physiological Society.

Exercise, oxidants, and antioxidants change the shape of the bell-shaped hormesis curve.

PubMed

Radak, Zsolt; Ishihara, Kazunari; Tekus, Eva; Varga, Csaba; Posa, Aniko; Balogh, Laszlo; Boldogh, Istvan; Koltai, Erika

2017-08-01

It is debated whether exercise-induced ROS production is obligatory to cause adaptive response. It is also claimed that antioxidant treatment could eliminate the adaptive response, which appears to be systemic and reportedly reduces the incidence of a wide range of diseases. Here we suggest that if the antioxidant treatment occurs before the physiological function-ROS dose-response curve reaches peak level, the antioxidants can attenuate function. On the other hand, if the antioxidant treatment takes place after the summit of the bell-shaped dose response curve, antioxidant treatment would have beneficial effects on function. We suggest that the effects of antioxidant treatment are dependent on the intensity of exercise, since the adaptive response, which is multi pathway dependent, is strongly influenced by exercise intensity. It is further suggested that levels of ROS concentration are associated with peak physiological function and can be extended by physical fitness level and this could be the basis for exercise pre-conditioning. Physical inactivity, aging or pathological disorders increase the sensitivity to oxidative stress by altering the bell-shaped dose response curve. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Central and Peripheral Fatigue During Resistance Exercise - A Critical Review.

PubMed

Zając, Adam; Chalimoniuk, Małgorzata; Maszczyk, Adam; Gołaś, Artur; Lngfort, Józef

2015-12-22

Resistance exercise is a popular form of conditioning for numerous sport disciplines, and recently different modes of strength training are being evaluated for health benefits. Resistance exercise differs significantly in nature, and several variables determine the direction and range of adaptive changes that occur in the muscular and skeletal system of the body. Some modes of resistance training can also be effective in stimulating the cardiovascular system. These variables include exercise selection (general, specific, single or multi joint, dynamic, explosive), type of resistance (free weights, variable resistance, isokinetics), order of exercise (upper and lower body or push and pull exercises), and most of all the training load which includes intensity expressed as % of 1RM, number of repetitions, number of sets and the rest interval between sets. Manipulating these variables allows for specific adaptive changes which may include gains in muscle mass, muscle strength or muscle endurance. It has been well established that during resistance exercise fatigue occurs, regardless of the volume and intensity of work applied. The peripheral mechanisms of fatigue have been studied and explained in more detail than those related to the CNS. This review is an attempt to bring together the latest knowledge regarding fatigue, both peripheral and central, during resistance exercise. The authors of this review concentrated on physiological and biochemical mechanisms underlying fatigue in exercises performed with maximal intensity, as well as those performed to exhaustion with numerous repetitions and submaximal load.

Longitudinal social cognitive influences on physical activity and sedentary time in Hispanic breast cancer survivors.

PubMed

Mama, Scherezade K; Song, Jaejoon; Ortiz, Alexis; Tirado-Gomez, Maribel; Palacios, Cristina; Hughes, Daniel C; Basen-Engquist, Karen

2017-02-01

This study evaluated the effect of two home-based exercise interventions (one culturally adapted and one standard) on changes in social cognitive theory (SCT) variables, physical activity (PA), and sedentary time (ST), and determined the association between changes in SCT variables and changes in PA and ST in Hispanic breast cancer survivors. Project VIVA! was a 16-week randomized controlled pilot study to test the effectiveness and feasibility of a culturally adapted exercise intervention for Mexican American and Puerto Rican breast cancer survivors in Houston, Texas and San Juan, Puerto Rico, respectively. Women (N = 89) completed questionnaires on SCT variables, PA, and ST and were then randomized to a 16-week culturally adapted exercise program, a non-culturally adapted standard exercise intervention or a wait-list control group. Multiple regression models were used to determine associations between changes in SCT variables and changes in PA and ST. Participants were in their late 50s (58.5 ± 9.2 years) and obese (31.0 ± 6.5 kg/m 2 ). Women reported doing roughly 34.5 min/day of PA and spending over 11 h/day in sedentary activities. Across groups, women reported significant increases in exercise self-efficacy and moderate-intensity, vigorous-intensity, and total PA from baseline to follow-up (p < 0.05). Increased social support from family was associated with increases in vigorous-intensity PA. Increases in social modeling were associated with increases in moderate-intensity and total PA and with decreases in ST from baseline to follow-up (p < 0.05). Hispanic cancer survivors benefit from PA interventions that focus on increasing social support from family and friends and social modeling. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

Therapeutic physical exercise in neural injury: friend or foe?

PubMed

Park, Kanghui; Lee, Seunghoon; Hong, Yunkyung; Park, Sookyoung; Choi, Jeonghyun; Chang, Kyu-Tae; Kim, Joo-Heon; Hong, Yonggeun

2015-12-01

[Purpose] The intensity of therapeutic physical exercise is complex and sometimes controversial in patients with neural injuries. This review assessed whether therapeutic physical exercise is beneficial according to the intensity of the physical exercise. [Methods] The authors identified clinically or scientifically relevant articles from PubMed that met the inclusion criteria. [Results] Exercise training can improve body strength and lead to the physiological adaptation of skeletal muscles and the nervous system after neural injuries. Furthermore, neurophysiological and neuropathological studies show differences in the beneficial effects of forced therapeutic exercise in patients with severe or mild neural injuries. Forced exercise alters the distribution of muscle fiber types in patients with neural injuries. Based on several animal studies, forced exercise may promote functional recovery following cerebral ischemia via signaling molecules in ischemic brain regions. [Conclusions] This review describes several types of therapeutic forced exercise and the controversy regarding the therapeutic effects in experimental animals versus humans with neural injuries. This review also provides a therapeutic strategy for physical therapists that grades the intensity of forced exercise according to the level of neural injury.

Effects of fat adaptation on glucose kinetics and substrate oxidation during low-intensity exercise.

PubMed

Pagan, J D; Geor, R J; Harris, P A; Hoekstra, K; Gardner, S; Hudson, C; Prince, A

2002-09-01

This study was designed to determine the effects of fat adaptation on carbohydrate and fat oxidation in conditioned horses during low-intensity exercise. Five mature Arabians were studied. The study was conducted as a crossover design with 2 dietary periods, each of 10 week's duration: a) a control (CON) diet, and b) a fat-supplemented (FAT) diet. The total amount of digestible energy (DE) supplied by the fat in the CON and FAT diets was 7% and 29%, respectively. During each period, the horses completed exercise tests at the beginning of the period (Week 0) and after 5 and 10 weeks on the diet. Tests consisted of 90 min of exercise at a speed calculated to elicit 35% VO2max on a treadmill inclined to 3 degrees. Oxygen consumption (VO2), carbon dioxide production (VCO2), and respiratory exchange ratio (RER) were measured at 15-min intervals. For determination of glucose kinetics, a stable isotope ([6-6-d2] glucose) technique was used. Compared to the CON diet, FAT diet consumption for 5-10 weeks was associated with an altered metabolic response to low-intensity exercise, as evidenced by a more than 30% reduction in the production and utilisation of glucose; a decrease in RER; a decrease in the estimated rate of whole-body carbohydrate utilisation; and an increase in the whole-body rate of lipid oxidation during exercise.

Short-Term Intensified Cycle Training Alters Acute and Chronic Responses of PGC1α and Cytochrome C Oxidase IV to Exercise in Human Skeletal Muscle

PubMed Central

Stepto, Nigel K.; Benziane, Boubacar; Wadley, Glenn D.; Chibalin, Alexander V.; Canny, Benedict J.; Eynon, Nir; McConell, Glenn K.

2012-01-01

Reduced activation of exercise responsive signalling pathways have been reported in response to acute exercise after training; however little is known about the adaptive responses of the mitochondria. Accordingly, we investigated changes in mitochondrial gene expression and protein abundance in response to the same acute exercise before and after 10-d of intensive cycle training. Nine untrained, healthy participants (mean±SD; VO2peak 44.1±17.6 ml/kg/min) performed a 60 min bout of cycling exercise at 164±18 W (72% of pre-training VO2peak). Muscle biopsies were obtained from the vastus lateralis muscle at rest, immediately and 3 h after exercise. The participants then underwent 10-d of cycle training which included four high-intensity interval training sessions (6×5 min; 90–100% VO2peak) and six prolonged moderate-intensity sessions (45–90 min; 75% VO2peak). Participants repeated the pre-training exercise trial at the same absolute work load (64% of pre-training VO2peak). Muscle PGC1-α mRNA expression was attenuated as it increased by 11- and 4- fold (P<0.001) after exercise pre- and post-training, respectively. PGC1-α protein expression increased 1.5 fold (P<0.05) in response to exercise pre-training with no further increases after the post-training exercise bout. RIP140 protein abundance was responsive to acute exercise only (P<0.01). COXIV mRNA (1.6 fold; P<0.01) and COXIV protein expression (1.5 fold; P<0.05) were increased by training but COXIV protein expression was decreased (20%; P<0.01) by acute exercise pre- and post-training. These findings demonstrate that short-term intensified training promotes increased mitochondrial gene expression and protein abundance. Furthermore, acute indicators of exercise-induced mitochondrial adaptation appear to be blunted in response to exercise at the same absolute intensity following short-term training. PMID:23285255

AMPK signaling in skeletal muscle during exercise: Role of reactive oxygen and nitrogen species.

PubMed

Morales-Alamo, David; Calbet, Jose A L

2016-09-01

Reactive oxygen and nitrogen species (RONS) are generated during exercise depending on intensity, duration and training status. A greater amount of RONS is released during repeated high-intensity sprint exercise and when the exercise is performed in hypoxia. By activating adenosine monophosphate-activated kinase (AMPK), RONS play a critical role in the regulation of muscle metabolism but also in the adaptive responses to exercise training. RONS may activate AMPK by direct an indirect mechanisms. Directly, RONS may activate or deactivate AMPK by modifying RONS-sensitive residues of the AMPK-α subunit. Indirectly, RONS may activate AMPK by reducing mitochondrial ATP synthesis, leading to an increased AMP:ATP ratio and subsequent Thr(172)-AMPK phosphorylation by the two main AMPK kinases: LKB1 and CaMKKβ. In presence of RONS the rate of Thr(172)-AMPK dephosphorylation is reduced. RONS may activate LKB1 through Sestrin2 and SIRT1 (NAD(+)/NADH.H(+)-dependent deacetylase). RONS may also activate CaMKKβ by direct modification of RONS sensitive motifs and, indirectly, by activating the ryanodine receptor (Ryr) to release Ca(2+). Both too high (hypoxia) and too low (ingestion of antioxidants) RONS levels may lead to Ser(485)-AMPKα1/Ser(491)-AMPKα2 phosphorylation causing inhibition of Thr(172)-AMPKα phosphorylation. Exercise training increases muscle antioxidant capacity. When the same high-intensity training is applied to arm and leg muscles, arm muscles show signs of increased oxidative stress and reduced mitochondrial biogenesis, which may be explained by differences in RONS-sensing mechanisms and basal antioxidant capacities between arm and leg muscles. Efficient adaptation to exercise training requires optimal exposure to pulses of RONS. Inappropriate training stimulus may lead to excessive RONS formation, oxidative inactivation of AMPK and reduced adaptation or even maladaptation. Theoretically, exercise programs should be designed taking into account the intrinsic properties of different skeletal muscles, the specific RONS induction and the subsequent signaling responses. Copyright © 2016 Elsevier Inc. All rights reserved.

Discrete physiological effects of beetroot juice and potassium nitrate supplementation following 4-wk sprint interval training.

PubMed

Thompson, Christopher; Vanhatalo, Anni; Kadach, Stefan; Wylie, Lee J; Fulford, Jonathan; Ferguson, Scott K; Blackwell, Jamie R; Bailey, Stephen J; Jones, Andrew M

2018-06-01

The physiological and exercise performance adaptations to sprint interval training (SIT) may be modified by dietary nitrate ([Formula: see text]) supplementation. However, it is possible that different types of [Formula: see text] supplementation evoke divergent physiological and performance adaptations to SIT. The purpose of this study was to compare the effects of 4-wk SIT with and without concurrent dietary [Formula: see text] supplementation administered as either [Formula: see text]-rich beetroot juice (BR) or potassium [Formula: see text] (KNO 3 ). Thirty recreationally active subjects completed a battery of exercise tests before and after a 4-wk intervention in which they were allocated to one of three groups: 1) SIT undertaken without dietary [Formula: see text] supplementation (SIT); 2) SIT accompanied by concurrent BR supplementation (SIT + BR); or 3) SIT accompanied by concurrent KNO 3 supplementation (SIT + KNO 3 ). During severe-intensity exercise, V̇o 2peak and time to task failure were improved to a greater extent with SIT + BR than SIT and SIT + KNO 3 ( P < 0.05). There was also a greater reduction in the accumulation of muscle lactate at 3 min of severe-intensity exercise in SIT + BR compared with SIT + KNO 3 ( P < 0.05). Plasma [Formula: see text] concentration fell to a greater extent during severe-intensity exercise in SIT + BR compared with SIT and SIT + KNO 3 ( P < 0.05). There were no differences between groups in the reduction in the muscle phosphocreatine recovery time constant from pre- to postintervention ( P > 0.05). These findings indicate that 4-wk SIT with concurrent BR supplementation results in greater exercise capacity adaptations compared with SIT alone and SIT with concurrent KNO 3 supplementation. This may be the result of greater NO-mediated signaling in SIT + BR compared with SIT + KNO 3 . NEW & NOTEWORTHY We compared the influence of different forms of dietary nitrate supplementation on the physiological and performance adaptations to sprint interval training (SIT). Compared with SIT alone, supplementation with nitrate-rich beetroot juice, but not potassium [Formula: see text], enhanced some physiological adaptations to training.

Is there a minimum intensity threshold for resistance training-induced hypertrophic adaptations?

PubMed

Schoenfeld, Brad J

2013-12-01

In humans, regimented resistance training has been shown to promote substantial increases in skeletal muscle mass. With respect to traditional resistance training methods, the prevailing opinion is that an intensity of greater than ~60 % of 1 repetition maximum (RM) is necessary to elicit significant increases in muscular size. It has been surmised that this is the minimum threshold required to activate the complete spectrum of fiber types, particularly those associated with the largest motor units. There is emerging evidence, however, that low-intensity resistance training performed with blood flow restriction (BFR) can promote marked increases in muscle hypertrophy, in many cases equal to that of traditional high-intensity exercise. The anabolic effects of such occlusion-based training have been attributed to increased levels of metabolic stress that mediate hypertrophy at least in part by enhancing recruitment of high-threshold motor units. Recently, several researchers have put forth the theory that low-intensity exercise (≤50 % 1RM) performed without BFR can promote increases in muscle size equal, or perhaps even superior, to that at higher intensities, provided training is carried out to volitional muscular failure. Proponents of the theory postulate that fatiguing contractions at light loads is simply a milder form of BFR and thus ultimately results in maximal muscle fiber recruitment. Current research indicates that low-load exercise can indeed promote increases in muscle growth in untrained subjects, and that these gains may be functionally, metabolically, and/or aesthetically meaningful. However, whether hypertrophic adaptations can equal that achieved with higher intensity resistance exercise (≤60 % 1RM) remains to be determined. Furthermore, it is not clear as to what, if any, hypertrophic effects are seen with low-intensity exercise in well-trained subjects as experimental studies on the topic in this population are lacking. Practical implications of these findings are discussed.

Potential adverse cardiac remodelling in highly trained athletes: still unknown clinical significance.

PubMed

Gabrielli, Luigi; Sitges, Marta; Chiong, Mario; Jalil, Jorge; Ocaranza, María; Llevaneras, Silvana; Herrera, Sebastian; Fernandez, Rodrigo; Saavedra, Rodrigo; Yañez, Fernando; Vergara, Luis; Diaz, Alexis; Lavandero, Sergio; Castro, Pablo

2018-06-12

Moderate endurance exercise has long been considered an essential element to maintain cardiovascular health, and sedentary behaviour in the general population has been related to a significant increase in all-causes of mortality, cardiovascular disease mortality and cardiovascular disease incidence. However, a growing group of people performs an intense exercise that leads to multiple heart adaptive changes that are collectively called "athlete's heart". In this review, we discussed the evidence of cardiac remodelling process secondary to repetitive and strenuous exercise in some predisposed athletes that produces intense and probably deleterious changes in cardiac morphology and function with no clear clinical significance in long-term follow-up. Moreover, we also discussed the individual biological response to exercise assessed by myocardial damage, inflammation, oxidative stress, fibrosis and ventricular hypertrophy biomarkers showing different intensities with equivalent exertion.

Effects of volume-based overload plyometric training on maximal-intensity exercise adaptations in young basketball players.

PubMed

Asadi, Abbas; Ramirez-Campillo, Rodrigo; Meylan, Cesar; Nakamura, Fabio Y; Cañas-Jamett, Rodrigo; Izquierdo, Mikel

2017-12-01

The aim of the present study was to compare maximal-intensity exercise adaptations in young basketball players (who were strong individuals at baseline) participating in regular basketball training versus regular plus a volume-based plyometric training program in the pre-season period. Young basketball players were recruited and assigned either to a plyometric with regular basketball training group (experimental group [EG]; N.=8), or a basketball training only group (control group [CG]; N.=8). The athletes in EG performed periodized (i.e., from 117 to 183 jumps per session) plyometric training for eight weeks. Before and after the intervention, players were assessed in vertical and broad jump, change of direction, maximal strength and a 60-meter sprint test. No significant improvements were found in the CG, while the EG improved vertical jump (effect size [ES] 2.8), broad jump (ES=2.4), agility T test (ES=2.2), Illinois agility test (ES=1.4), maximal strength (ES=1.8), and 60-m sprint (ES=1.6) (P<0.05) after intervention, and the improvements were greater compared to the CG (P<0.05). Plyometric training in addition to regular basketball practice can lead to meaningful improvements in maximal-intensity exercise adaptations among young basketball players during the pre-season.

Moderate-to-high intensity aerobic exercise in patients with mild to moderate Alzheimer's disease: a pilot study.

PubMed

Frederiksen, Kristian S; Sobol, Nanna; Beyer, Nina; Hasselbalch, Steen; Waldemar, Gunhild

2014-12-01

Physical exercise may modulate neuropathology and symptoms of Alzheimer's disease (AD). This pilot study assessed the feasibility of conducting a study of moderate-to-high intensity aerobic exercise in home-dwelling patients with mild AD. An uncontrolled preintervention-postintervention test design with a single group receiving the same intervention. A total of eight patients with mild to moderate AD from the Copenhagen Memory clinic were included in the study. The intervention lasted for 14 weeks and consisted of supervised, 1-h sessions of aerobic exercise three times per week (50-60% of heart rate reserve for a two-week adaptation period and 70-80 % of heart rate reserve for the remaining 12 weeks) Feasibility was assessed based on acceptability, including attendance and drop-out, safety, and patients' and caregivers' attitudes towards the intervention as well as other relevant parameters. Attendance (mean, range: 90 %, 70-100 %) and retention (seven out of eight) rates were very high. No serious adverse events were observed. In general, patients and caregivers were positive towards the intervention. This study shows that it is feasible to conduct moderate-to-high intensity aerobic exercise in community-dwelling patients with mild AD. Our findings indicate that aspects such as a longer adaptation period, information about injury prevention, and need for involvement and support from caregivers should be addressed when planning an exercise intervention in an AD population. Copyright © 2014 John Wiley & Sons, Ltd.

κ-opioid receptor is involved in the cardioprotection induced by exercise training

PubMed Central

Li, Juan; Tian, Fei; Feng, Na; Fan, Rong; Jia, Min; Guo, Haitao; Cheng, Liang; Liu, Jincheng; Chen, Wensheng; Pei, Jianming

2017-01-01

The present study was designed to test the hypothesis that exercise training elicited a cardioprotective effect against ischemia and reperfusion (I/R) via the κ-opioid receptor (κ-OR)-mediated signaling pathway. Rats were randomly divided into four groups: the control group, the moderate intensity exercise (ME) group, the high intensity exercise (HE) group, and the acute exercise (AE) group. For the exercise training protocols, the rats were subjected to one week of adaptive treadmill training, while from the second week, the ME and HE groups were subjected to eight weeks of exercise training, and the AE group was subjected to three days of adaptive treadmill training and one day of vigorous exercise. After these protocols, the three exercise training groups were divided into different treatment groups, and the rats were subjected to 30 min of ischemia and 120 min of reperfusion. Changes in infarct size and serum cTnT (cardiac troponin T) caused by I/R were reduced by exercise training. Moreover, cardiac dysfunction caused by I/R was also alleviated by exercise training. These effects of exercise training were reversed by nor-BNI (a selective κ-OR antagonist), Compound C (a selective AMPK inhibitor), Akt inhibitor and L-NAME (a non-selective eNOS inhibitor). Expression of κ-OR and phosphorylation of AMPK, Akt and eNOS were significantly increased in the ME, HE and AE groups. These findings demonstrated that the cardioprotective effect of exercise training is possibly mediated by the κ-OR-AMPK-Akt-eNOS signaling pathway. PMID:28301473

Influence of Disease Severity and Exercise Limitation on Exercise Training Intensity and Load and Health Benefits From Pulmonary Rehabilitation in Patients with COPD: AN EXPLORATORY STUDY.

PubMed

Huynh, Virginia C; Fuhr, Desi P; Byers, Bradley W; Selzler, Anne-Marie; Moore, Linn E; Stickland, Michael K

2018-04-11

Some patients with chronic obstructive pulmonary disease (COPD) fail to achieve health benefits with pulmonary rehabilitation (PR). Exercise intensity and load represent stimulus for adaptation but it is unclear whether inappropriate exercise intensity and/or load are affected by severity of COPD, which may affect health benefits. The purpose was to determine whether COPD severity and/or the severity of pulmonary limitation to exercise (PLE) impacted exercising intensity or load and whether resultant intensity/load affected health outcomes derived from PR. Patients with COPD (n = 58, age = 67 ± 7 y, forced expiratory volume in the first second of expiration [FEV1] % predicted = 52 ± 21%) were recruited upon referral to PR. Primary health outcomes evaluated were 6-min walk distance and St George's Respiratory Questionnaire. Patients were stratified for disease severity using Global Initiative for Obstructive Lung Disease (GOLD) staging and PLE severity by change in inspiratory capacity during exercise. Exercise intensity and load were calculated from daily exercise records. Participants achieved comparable training duration and load regardless of GOLD severity. Patients with more severe PLE achieved greater training duration (more severe: 546 ± 143 min., less severe: 451 ± 109 min., P = .036), and relative training load (more severe: 2200.8 ± 595.3 kcal, less severe: 1648.3 ± 597.8 kcal, P = .007). Greater overall training load was associated with greater improvements in 6-min walk distance (r = 0.24, P = .035). No significant relationships were observed between PLE, GOLD severity, training parameters, and St George's Respiratory Questionnaire response. Improvements in exercise tolerance can be explained by achieving greater training loads, demonstrating the importance of appropriate training load to maximize health outcomes in PR.

Energy Intake and Exercise as Determinants of Brain Health and Vulnerability to Injury and Disease

PubMed Central

Mattson, Mark P.

2012-01-01

Evolution favored individuals with superior cognitive and physical abilities under conditions of limited food sources, and brain function can therefore be optimized by intermittent dietary energy restriction (ER) and exercise. Such energetic challenges engage adaptive cellular stress response signaling pathways in neurons involving neurotrophic factors, protein chaperones, DNA repair proteins, autophagy and mitochondrial biogenesis. By suppressing adaptive cellular stress responses, overeating and a sedentary lifestyle may increase the risk of Alzheimer’s and Parkinson’s diseases, stroke, and depression. Intense concerted efforts of governments, families, schools and physicians will be required to successfully implement brain-healthy lifestyles that incorporate ER and exercise. PMID:23168220

Regulation of Muscle Glycogen Metabolism during Exercise: Implications for Endurance Performance and Training Adaptations

PubMed Central

Hearris, Mark A.; Hammond, Kelly M.; Fell, J. Marc; Morton, James P.

2018-01-01

Since the introduction of the muscle biopsy technique in the late 1960s, our understanding of the regulation of muscle glycogen storage and metabolism has advanced considerably. Muscle glycogenolysis and rates of carbohydrate (CHO) oxidation are affected by factors such as exercise intensity, duration, training status and substrate availability. Such changes to the global exercise stimulus exert regulatory effects on key enzymes and transport proteins via both hormonal control and local allosteric regulation. Given the well-documented effects of high CHO availability on promoting exercise performance, elite endurance athletes are typically advised to ensure high CHO availability before, during and after high-intensity training sessions or competition. Nonetheless, in recognition that the glycogen granule is more than a simple fuel store, it is now also accepted that glycogen is a potent regulator of the molecular cell signaling pathways that regulate the oxidative phenotype. Accordingly, the concept of deliberately training with low CHO availability has now gained increased popularity amongst athletic circles. In this review, we present an overview of the regulatory control of CHO metabolism during exercise (with a specific emphasis on muscle glycogen utilization) in order to discuss the effects of both high and low CHO availability on modulating exercise performance and training adaptations, respectively. PMID:29498691

Effect of different blood-guided conditioning programmes on skeletal muscle ultrastructure and histochemistry of sport horses.

PubMed

Lindner, A; Dag Erginsoy, S; Kissenbeck, S; Mosen, H; Hetzel, U; Drommer, W; Chamizo, V E; Rivero, J L L

2013-04-01

The effects of three different blood-guided conditioning programmes on ultrastructural and histochemical features of the gluteus medius muscle of 2-year-old sport horses were examined. Six non-trained Haflinger horses performed three consecutive conditioning programmes of varying lactate-guided intensities [velocities eliciting blood lactate concentrations of 1.5 (v1.5 ), 2.5 (v2.5 ) and 4 (v4 ) mm respectively] and durations (25 and 45 min). Each conditioning programme lasted 6 weeks and was followed by a 5-week resting period. Pre-, post- and deconditioning muscle biopsies were analysed. Although training and detraining adaptations were similar in nature, they varied significantly in magnitude among the three different conditioning programmes. Overall, the adaptations consisted in significant increases in size of mitochondria and myofibrils, as well as a hypertrophy of myofibrillar ATPase type IIA muscle fibres and a reduction in number of type IIx low-oxidative fibres. Together, these changes are compatible with a significant improvement in both muscle aerobic capacity and muscle strength. The use of v1.5 and v2.5 as the exercise intensities for 45 min elicited more significant adaptations in muscle, whereas conditioning horses at v4 for 25 min evoked minimal changes. Most of these muscular adaptations returned towards the pre-conditioning status after 5 weeks of inactivity. It is concluded that exercises of low or moderate intensities (in the range between v1.5 and v2.5 ) and long duration (45 min) are more effective for improving muscle features associated with stamina and power in sport horses than exercises of higher intensity (equivalent to v4 ) and shorter duration (25 min). © 2012 Blackwell Verlag GmbH.

Dose-response relationship of cardiorespiratory fitness adaptation to controlled endurance training in sedentary older adults.

PubMed

Huang, Guoyuan; Wang, Ru; Chen, Peijie; Huang, Sunny C; Donnelly, Joseph E; Mehlferber, Jon P

2016-03-01

The purpose of this investigation was to identify a quantitative dose-response relationship for enhancing maximal oxygen consumption (VO2max) in healthy sedentary older adults after controlled endurance training. This meta-analysis of controlled clinical trials included 1257 exercisers and 845 controls with a mean age of 67.45 ± 5.25 years. Effect sizes were calculated for training-induced VO2max changes. Different training regimens were analyzed and compared. The weighted net change of the mean VO2max values showed a significant increase of 3.78 ml/kg per min (95% confidence interval = 3.29 to 4.27; p < 0.0001) in response to aerobic training. Interstudy differences in VO2max changes were significantly related to exercise intensity, and explained approximately 11% of the variance of the VO2max responses. VO2max improved significantly at 35%-50% heart rate reserve (HRR) and continued improving at a greater rate with increasing "dose". The largest VO2max-improvement adaptation was achieved with a mean intensity of 66%-73% HRR. The magnitudes of the VO2max adaptation are identical to exercise at 57%-65% HRR and at 75%-80% HRR. Higher intensity doses more than 75-80% HRR did not lead to greater enhancement of VO2max improvements but, conversely, resulted in large declines. Our data provide quantitative insight into the magnitude of VO2max alterations as affected by exercise intensity, duration, frequency, and program length. The shapes of the dose-response curves are not simply linear, but with many similar trends and noteworthy characteristics. Aerobic training at a mean intensity of 66%-73% HRR with 40-50 min per session for 3-4 day/week for 30-40 weeks appears to be effective and optimal for maximum cardiorespiratory benefits in healthy sedentary older adults. © The European Society of Cardiology 2015.

The Assessment of Muscular Effort, Fatigue, and Physiological Adaptation Using EMG and Wavelet Analysis.

PubMed

Graham, Ryan B; Wachowiak, Mark P; Gurd, Brendon J

2015-01-01

Peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1α) is a transcription factor co-activator that helps coordinate mitochondrial biogenesis within skeletal muscle following exercise. While evidence gleaned from submaximal exercise suggests that intracellular pathways associated with the activation of PGC-1α, as well as the expression of PGC-1α itself are activated to a greater extent following higher intensities of exercise, we have recently shown that this effect does not extend to supramaximal exercise, despite corresponding increases in muscle activation amplitude measured with electromyography (EMG). Spectral analyses of EMG data may provide a more in-depth assessment of changes in muscle electrophysiology occurring across different exercise intensities, and therefore the goal of the present study was to apply continuous wavelet transforms (CWTs) to our previous data to comprehensively evaluate: 1) differences in muscle electrophysiological properties at different exercise intensities (i.e. 73%, 100%, and 133% of peak aerobic power), and 2) muscular effort and fatigue across a single interval of exercise at each intensity, in an attempt to shed mechanistic insight into our previous observations that the increase in PGC-1α is dissociated from exercise intensity following supramaximal exercise. In general, the CWTs revealed that localized muscle fatigue was only greater than the 73% condition in the 133% exercise intensity condition, which directly matched the work rate results. Specifically, there were greater drop-offs in frequency, larger changes in burst power, as well as greater changes in burst area under this intensity, which were already observable during the first interval. As a whole, the results from the present study suggest that supramaximal exercise causes extreme localized muscular fatigue, and it is possible that the blunted PGC-1α effects observed in our previous study are the result of fatigue-associated increases in muscle acidosis. This should be explored in future research using further combinations of EMG and muscle biochemistry and histology.

End-exercise ΔHHb/ΔVO2 and post-exercise local oxygen availability in relation to exercise intensity.

PubMed

Stöcker, F; Von Oldershausen, C; Paternoster, F K; Schulz, T; Oberhoffer, R

2017-07-01

Increased local blood supply is thought to be one of the mechanisms underlying oxidative adaptations to interval training regimes. The relationship of exercise intensity with local blood supply and oxygen availability has not been sufficiently evaluated yet. The aim of this study was to examine the effect of six different intensities (40-90% peak oxygen uptake, VO 2peak ) on relative changes in oxygenated, deoxygenated and total haemoglobin (ΔO 2 Hb, ΔHHb, ΔTHb) concentration after exercise as well as end-exercise ΔHHb/ΔVO 2 as a marker for microvascular O 2 distribution. Seventeen male subjects performed an experimental protocol consisting of 3 min cycling bouts at each exercise intensity in randomized order, separated by 5 min rests. ΔO 2 Hb and ΔHHb were monitored with near-infrared spectroscopy of the vastus lateralis muscle, and VO 2 was assessed. ΔHHb/ΔVO 2 increased significantly from 40% to 60% VO 2 peak and decreased from 60% to 90% VO 2 peak. Post-exercise ΔTHb and ΔO 2 Hb showed an overshoot in relation to pre-exercise values, which was equal after 40-60% VO 2peak and rose significantly thereafter. A plateau was reached following exercise at ≥80% VO 2peak . The results suggest that there is an increasing mismatch of local O 2 delivery and utilization during exercise up to 60% VO 2peak . This insufficient local O 2 distribution is progressively improved above that intensity. Further, exercise intensities of ≥80% VO 2peak induce highest local post-exercise O 2 availability. These effects are likely due to improved microvascular perfusion by enhanced vasodilation, which could be mediated by higher lactate production and the accompanying acidosis. © 2015 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

Adaptations and mechanisms of human heat acclimation: Applications for competitive athletes and sports.

PubMed

Périard, J D; Racinais, S; Sawka, M N

2015-06-01

Exercise heat acclimation induces physiological adaptations that improve thermoregulation, attenuate physiological strain, reduce the risk of serious heat illness, and improve aerobic performance in warm-hot environments and potentially in temperate environments. The adaptations include improved sweating, improved skin blood flow, lowered body temperatures, reduced cardiovascular strain, improved fluid balance, altered metabolism, and enhanced cellular protection. The magnitudes of adaptations are determined by the intensity, duration, frequency, and number of heat exposures, as well as the environmental conditions (i.e., dry or humid heat). Evidence is emerging that controlled hyperthermia regimens where a target core temperature is maintained, enable more rapid and complete adaptations relative to the traditional constant work rate exercise heat acclimation regimens. Furthermore, inducing heat acclimation outdoors in a natural field setting may provide more specific adaptations based on direct exposure to the exact environmental and exercise conditions to be encountered during competition. This review initially examines the physiological adaptations associated with heat acclimation induction regimens, and subsequently emphasizes their application to competitive athletes and sports. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Promoting training adaptations through nutritional interventions.

PubMed

Hawley, John A; Tipton, Kevin D; Millard-Stafford, Mindy L

2006-07-01

Training and nutrition are highly interrelated in that optimal adaptation to the demands of repeated training sessions typically requires a diet that can sustain muscle energy reserves. As nutrient stores (i.e. muscle and liver glycogen) play a predominant role in the performance of prolonged, intense, intermittent exercise typical of the patterns of soccer match-play, and in the replenishment of energy reserves for subsequent training sessions, the extent to which acutely altering substrate availability might modify the training impulse has been a key research area among exercise physiologists and sport nutritionists for several decades. Although the major perturbations to cellular homeostasis and muscle substrate stores occur during exercise, the activation of several major signalling pathways important for chronic training adaptations take place during the first few hours of recovery, returning to baseline values within 24 h after exercise. This has led to the paradigm that many chronic training adaptations are generated by the cumulative effects of the transient events that occur during recovery from each (acute) exercise bout. Evidence is accumulating that nutrient supplementation can serve as a potent modulator of many of the acute responses to both endurance and resistance training. In this article, we review the molecular and cellular events that occur in skeletal muscle during exercise and subsequent recovery, and the potential for nutrient supplementation (e.g. carbohydrate, fat, protein) to affect many of the adaptive responses to training.

Effect of exercise intensity on circulating microparticles in men and women.

PubMed

Shill, Daniel D; Lansford, Kasey A; Hempel, Hannah K; Call, Jarrod A; Murrow, Jonathan R; Jenkins, Nathan T

2018-05-01

What is the central question of this study? What is the effect of exercise intensity on circulating microparticle populations in young, healthy men and women? What is the main finding and its importance? Acute, moderate-intensity continuous exercise and high-intensity interval exercise altered distinct microparticle populations during and after exercise in addition to a sex-specific response in CD62E + microparticles. The microparticles studied contribute to cardiovascular disease progression, regulate vascular function and facilitate new blood vessel formation. Thus, characterizing the impact of intensity on exercise-induced microparticle responses advances our understanding of potential mechanisms underlying the beneficial vascular adaptations to exercise. Circulating microparticles (MPs) are biological vectors of information within the cardiovascular system that elicit both deleterious and beneficial effects on the vasculature. Acute exercise has been shown to alter MP concentrations, probably through a shear stress-dependent mechanism, but evidence is limited. Therefore, we investigated the effect of exercise intensity on plasma levels of CD34 + and CD62E + MPs in young, healthy men and women. Blood samples were collected before, during and after two energy-matched bouts of acute treadmill exercise: interval exercise (10 × 1 min intervals at ∼95% of maximal oxygen uptake V̇O2max) and continuous exercise (65% V̇O2max). Continuous exercise, but not interval exercise, reduced CD62E + MP concentrations in men and women by 18% immediately after exercise (from 914.5 ± 589.6 to 754.4 ± 390.5 MPs μl -1 ; P < 0.05), suggesting that mechanisms underlying exercise-induced CD62E + MP dynamics are intensity dependent. Furthermore, continuous exercise reduced CD62E + MPs in women by 19% (from 1030.6 ± 688.1 to 829.9 ± 435.4 MPs μl -1 ; P < 0.05), but not in men. Although interval exercise did not alter CD62E + MPs per se, the concentrations after interval exercise were higher than those observed after continuous exercise (P < 0.05). Conversely, CD34 + MPs did not fluctuate in response to short-duration acute continuous or interval exercise in men or women. Our results suggest that exercise-induced MP alterations are intensity dependent and sex specific and impact MP populations differentially. © 2018 The Authors. Experimental Physiology © 2018 The Physiological Society.

Aerobic Fitness Level Typical of Elite Athletes is not Associated With Even Faster VO2 Kinetics During Cycling Exercise

PubMed Central

Figueira, Tiago R.; Caputo, Fabrizio; Machado, Carlos E.P.; Denadai, Benedito S.

2008-01-01

The aim of this study was to address the question if the VO2 kinetics is further improved as the aerobic training status increases from trained to elite level athletes. Maximal oxygen uptake (VO2max), work-rate associated to VO2max (IVO2max) and VO2 kinetics of moderate (Mod) and maximal exercise (Max) were determined in fifty- five subjects. Then, they were assigned into three groups: low (LF), intermediate (IF) and high (HF) aerobic fitness level. In average, the VO2max of LF, IF and HF groups were, respectively, 36.0 ± 3.1, 51.1 ± 4.5 and 68.1 ± 3.9 ml·kg·min-1 (p ≤ 0.05 among each other). VO2 kinetics mean response time of both exercise intensities were significantly faster (p ≤ 0.05) in HF (Mod, 27.5 ± 5.5 s; Max, 32.6 ± 8.3 s) and IF (Mod, 25.0 ± 3.1 s; Max, 42.6 ± 10.4 s) when compared to LF (Mod, 35.7 ± 7.9 s; Max: 57.8 ± 17.8 s). We can conclude that VO2 kinetics is improved as the fitness level is increased from low to intermediate but not further improved as the aerobic fitness level increases from intermediate to high. Key points Currently, it is reasonable to believe that the rate-limiting step of VO2 kinetics depends on exercise intensity. The well known physiological adaptations induced by endurance training are likely the most extreme means to overcome rate-limiting steps determining VO2 kinetics across exercise intensities. However, exercise adaptation leading individuals to the high-end of aerobic fitness level range (VO2max > 65 ml.kg.min-1) is not able to further improve VO2 kinetics during both, moderate and maximal intensity exercise. PMID:24150145

Greater impact of acute high-intensity interval exercise on post-exercise executive function compared to moderate-intensity continuous exercise.

PubMed

Tsukamoto, Hayato; Suga, Tadashi; Takenaka, Saki; Tanaka, Daichi; Takeuchi, Tatsuya; Hamaoka, Takafumi; Isaka, Tadao; Hashimoto, Takeshi

2016-03-01

Aerobic moderate-intensity continuous exercise (MCE) can improve executive function (EF) acutely, potentially through the activation of both physiological and psychological factors. Recently, high-intensity interval exercise (HIIE) has been reported to be more beneficial for physical adaptation than MCE. Factors for EF improvement can potentially be more enhanced by HIIE than by MCE; but the effects of HIIE on EF remain unknown. Therefore, we aimed to examine to what extent HIIE impacts post-exercise EF immediately after exercise and during post-exercise recovery, compared with traditional MCE. Twelve healthy male subjects performed cycle ergometer exercise based on either HIIE or MCE protocols in a randomized and counterbalanced order. The HIIE protocol consisted of four 4-min bouts at 90% of peak VO2 with 3-min active recovery at 60% of peak VO2. A volume-matched MCE protocol was applied at 60% of peak VO2. To evaluate EF, a color-words Stroop task was performed pre- and post-exercise. Improvement in EF immediately after exercise was the same for the HIIE and MCE protocols. However, the improvement of EF by HIIE was sustained during 30 min of post-exercise recovery, during which MCE returned to the pre-exercise level. The EF response in the post-exercise recovery was associated with changes in physiological and psychological responses. The present findings showed that HIIE and MCE were capable of improving EF. Moreover, HIIE could prolong improvement in EF during post-exercise recovery. For the first time, we suggest that HIIE may be more effective strategy than MCE for improving EF. Copyright © 2015 Elsevier Inc. All rights reserved.

Upright exercise or supine lower body negative pressure exercise maintains exercise responses after bed rest

NASA Technical Reports Server (NTRS)

Lee, S. M.; Bennett, B. S.; Hargens, A. R.; Watenpaugh, D. E.; Ballard, R. E.; Murthy, G.; Ford, S. R.; Fortney, S. M.

1997-01-01

Adaptation to bed rest or space flight is accompanied by an impaired ability to exercise in an upright position. We hypothesized that a daily, 30-min bout of intense, interval exercise in upright posture or supine against lower body negative pressure (LBNP) would maintain upright exercise heart rate and respiratory responses after bed rest. Twenty-four men (31 +/- 3 yr) underwent 5 d of 6 degree head-down tilt: eight performed no exercise (CON), eight performed upright treadmill exercise (UPex), and eight performed supine treadmill exercise against LBNP at -51.3 +/- 0.4 mm Hg (LBNPex). Submaximal treadmill exercise responses (56, 74, and 85% of VO2peak) were measured pre- and post-bed rest. In CON, submaximal heart rate, respiratory exchange ratio, and ventilation were significantly greater (P < or = 0.05) after bed rest. In UPex and LBNPex, submaximal exercise responses were similar pre- and post-bed rest. Our results indicate that a daily 30-min bout of intense, interval upright exercise training or supine exercise training against LBNP is sufficient to maintain upright exercise responses after 5 d of bed rest. These results may have important implications for the development of exercise countermeasures during space flight.

Closed-Loop Neuroprosthesis for Reach-to-Grasp Assistance: Combining Adaptive Multi-channel Neuromuscular Stimulation with a Multi-joint Arm Exoskeleton.

PubMed

Grimm, Florian; Gharabaghi, Alireza

2016-01-01

Stroke patients with severe motor deficits cannot execute task-oriented rehabilitation exercises with their affected upper extremity. Advanced rehabilitation technology may support them in performing such reach-to-grasp movements. The challenge is, however, to provide assistance as needed, while maintaining the participants' commitment during the exercises. In this feasibility study, we introduced a closed-loop neuroprosthesis for reach-to-grasp assistance which combines adaptive multi-channel neuromuscular stimulation with a multi-joint arm exoskeleton. Eighteen severely affected chronic stroke patients were assisted by a gravity-compensating, seven-degree-of-freedom exoskeleton which was attached to the paretic arm for performing reach-to-grasp exercises resembling activities of daily living in a virtual environment. During the exercises, adaptive electrical stimulation was applied to seven different muscles of the upper extremity in a performance-dependent way to enhance the task-oriented movement trajectory. The stimulation intensity was individualized for each targeted muscle and remained subthreshold, i.e., induced no overt support. Closed-loop neuromuscular stimulation could be well integrated into the exoskeleton-based training, and increased the task-related range of motion (p = 0.0004) and movement velocity (p = 0.015), while preserving accuracy. The highest relative stimulation intensity was required to facilitate the grasping function. The facilitated range of motion correlated with the upper extremity Fugl-Meyer Assessment score of the patients (p = 0.028). Combining adaptive multi-channel neuromuscular stimulation with antigravity assistance amplifies the residual motor capabilities of severely affected stroke patients during rehabilitation exercises and may thus provide a customized training environment for patient-tailored support while preserving the participants' engagement.

Closed-Loop Neuroprosthesis for Reach-to-Grasp Assistance: Combining Adaptive Multi-channel Neuromuscular Stimulation with a Multi-joint Arm Exoskeleton

PubMed Central

Grimm, Florian; Gharabaghi, Alireza

2016-01-01

Stroke patients with severe motor deficits cannot execute task-oriented rehabilitation exercises with their affected upper extremity. Advanced rehabilitation technology may support them in performing such reach-to-grasp movements. The challenge is, however, to provide assistance as needed, while maintaining the participants' commitment during the exercises. In this feasibility study, we introduced a closed-loop neuroprosthesis for reach-to-grasp assistance which combines adaptive multi-channel neuromuscular stimulation with a multi-joint arm exoskeleton. Eighteen severely affected chronic stroke patients were assisted by a gravity-compensating, seven-degree-of-freedom exoskeleton which was attached to the paretic arm for performing reach-to-grasp exercises resembling activities of daily living in a virtual environment. During the exercises, adaptive electrical stimulation was applied to seven different muscles of the upper extremity in a performance-dependent way to enhance the task-oriented movement trajectory. The stimulation intensity was individualized for each targeted muscle and remained subthreshold, i.e., induced no overt support. Closed-loop neuromuscular stimulation could be well integrated into the exoskeleton-based training, and increased the task-related range of motion (p = 0.0004) and movement velocity (p = 0.015), while preserving accuracy. The highest relative stimulation intensity was required to facilitate the grasping function. The facilitated range of motion correlated with the upper extremity Fugl-Meyer Assessment score of the patients (p = 0.028). Combining adaptive multi-channel neuromuscular stimulation with antigravity assistance amplifies the residual motor capabilities of severely affected stroke patients during rehabilitation exercises and may thus provide a customized training environment for patient-tailored support while preserving the participants' engagement. PMID:27445658

Experiences of older people with dementia participating in a high-intensity functional exercise program in nursing homes: "While it's tough, it's useful"

PubMed Central

Lundin-Olsson, Lillemor; Skelton, Dawn A.; Lundman, Berit; Rosendahl, Erik

2017-01-01

The objective of the study was to describe the views and experiences of participation in a high-intensity functional exercise (HIFE) program among older people with dementia in nursing homes. The study design was a qualitative interview study with 21 participants (15 women), aged 74–96, and with a Mini-Mental State Examination score of 10–23 at study start. The HIFE-program comprises exercises performed in functional weight-bearing positions and including movements used in everyday tasks. The exercise was individually designed, supervised in small groups in the nursing homes and performed during four months. Interviews were performed directly after exercise sessions and field notes about the sessions were recorded. Qualitative content analysis was used for analyses. The analysis revealed four themes: Exercise is challenging but achievable; Exercise gives pleasure and strength; Exercise evokes body memories; and Togetherness gives comfort, joy, and encouragement. The intense and tailored exercise, adapted to each participant, was perceived as challenging but achievable, and gave pleasure and improvements in mental and bodily strength. Memories of previous physical activities aroused and participants rediscovered bodily capabilities. Importance of individualized and supervised exercise in small groups was emphasized and created feelings of encouragement, safety, and coherence. The findings from the interviews reinforces the positive meaning of intense exercise to older people with moderate to severe dementia in nursing homes. The participants were able to safely adhere to and understand the necessity of the exercise. Providers of exercise should consider the aspects valued by participants, e.g. supervision, individualization, small groups, encouragement, and that exercise involved joy and rediscovery of body competencies. PMID:29149198

Experiences of older people with dementia participating in a high-intensity functional exercise program in nursing homes: "While it's tough, it's useful".

PubMed

Lindelöf, Nina; Lundin-Olsson, Lillemor; Skelton, Dawn A; Lundman, Berit; Rosendahl, Erik

2017-01-01

The objective of the study was to describe the views and experiences of participation in a high-intensity functional exercise (HIFE) program among older people with dementia in nursing homes. The study design was a qualitative interview study with 21 participants (15 women), aged 74-96, and with a Mini-Mental State Examination score of 10-23 at study start. The HIFE-program comprises exercises performed in functional weight-bearing positions and including movements used in everyday tasks. The exercise was individually designed, supervised in small groups in the nursing homes and performed during four months. Interviews were performed directly after exercise sessions and field notes about the sessions were recorded. Qualitative content analysis was used for analyses. The analysis revealed four themes: Exercise is challenging but achievable; Exercise gives pleasure and strength; Exercise evokes body memories; and Togetherness gives comfort, joy, and encouragement. The intense and tailored exercise, adapted to each participant, was perceived as challenging but achievable, and gave pleasure and improvements in mental and bodily strength. Memories of previous physical activities aroused and participants rediscovered bodily capabilities. Importance of individualized and supervised exercise in small groups was emphasized and created feelings of encouragement, safety, and coherence. The findings from the interviews reinforces the positive meaning of intense exercise to older people with moderate to severe dementia in nursing homes. The participants were able to safely adhere to and understand the necessity of the exercise. Providers of exercise should consider the aspects valued by participants, e.g. supervision, individualization, small groups, encouragement, and that exercise involved joy and rediscovery of body competencies.

Increased ceramide content and NFkB signaling may contribute to the attenuation of anabolic signaling after resistance exercise in aged males

USDA-ARS?s Scientific Manuscript database

One of the most fundamental adaptive physiological events is the response of skeletal muscle to high-intensity resistance exercise, resulting in increased protein synthesis and ultimately larger muscle mass. However, muscle growth in response to contraction is attenuated in older humans. Impaired co...

Effects of Multicomponent Exercise on Functional and Cognitive Parameters of Hypertensive Patients: A Quasi-Experimental Study

PubMed Central

Feriani, Daniele Jardim; Gonçalves, Ivan de Oliveira; Asano, Ricardo Yukio; Aguiar, Samuel da Silva; Uchida, Marco Carlos

2017-01-01

Purpose. The present study aimed to investigate the impact of a 6-month multicomponent exercise program (MCEP) on physical function and cognitive parameters of normotensive (NTS) and hypertensive (HTS) older patients and verify if age can influence the adaptations in response to the exercise. Methods. A total of 218 subjects, 101 NTS and 117 HTS, were recruited and underwent functional and cognitive evaluations before and after six months of a MCEP. The program of exercise was performed twice a week, for 26 weeks. The physical exercises were thought to mimic the activities of daily living and, therefore, aggregated functional and walking exercises. Exercise sessions were performed at moderate intensity. Results. Data indicated that HTS and NST patients showed a similar increase in the performance of walking speed test and one-leg stand test after the MCEP. Regarding age, results did not show differences in the magnitude of adaptations between old and young HTS and NTS patients. Conclusions. Data of the present study indicated that a 6-month MCEP was able to increase equally balance and mobility in NTS and HTS patients. Moreover, data demonstrated that aging did not seem to impair the capacity to adapt in response to exercise in both groups. PMID:28409030

Long‐term exercise‐specific neuroprotection in spinal muscular atrophy‐like mice

PubMed Central

Chali, Farah; Desseille, Céline; Houdebine, Léo; Benoit, Evelyne; Rouquet, Thaïs; Bariohay, Bruno; Lopes, Philippe; Branchu, Julien; Della Gaspera, Bruno; Pariset, Claude; Chanoine, Christophe; Charbonnier, Frédéric

2016-01-01

Key points The real impact of physical exercise parameters, i.e. intensity, type of contraction and solicited energetic metabolism, on neuroprotection in the specific context of neurodegeneration remains poorly explored.In this study behavioural, biochemical and cellular analyses were conducted to compare the effects of two different long‐term exercise protocols, high intensity swimming and low intensity running, on motor units of a type 3 spinal muscular atrophy (SMA)‐like mouse model.Our data revealed a preferential SMA‐induced death of intermediate and fast motor neurons which was limited by the swimming protocol only, suggesting a close relationship between neuron‐specific protection and their activation levels by specific exercise.The exercise‐induced neuroprotection was independent of SMN protein expression and associated with specific metabolic and behavioural adaptations with notably a swimming‐induced reduction of muscle fatigability.Our results provide new insight into the motor units’ adaptations to different physical exercise parameters and will contribute to the design of new active physiotherapy protocols for patient care. Abstract Spinal muscular atrophy (SMA) is a group of autosomal recessive neurodegenerative diseases differing in their clinical outcome, characterized by the specific loss of spinal motor neurons, caused by insufficient level of expression of the protein survival of motor neuron (SMN). No cure is at present available for SMA. While physical exercise might represent a promising approach for alleviating SMA symptoms, the lack of data dealing with the effects of different exercise types on diseased motor units still precludes the use of active physiotherapy in SMA patients. In the present study, we have evaluated the efficiency of two long‐term physical exercise paradigms, based on either high intensity swimming or low intensity running, in alleviating SMA symptoms in a mild type 3 SMA‐like mouse model. We found that 10 months’ physical training induced significant benefits in terms of resistance to muscle damage, energetic metabolism, muscle fatigue and motor behaviour. Both exercise types significantly enhanced motor neuron survival, independently of SMN expression, leading to the maintenance of neuromuscular junctions and skeletal muscle phenotypes, particularly in the soleus, plantaris and tibialis of trained mice. Most importantly, both exercises significantly improved neuromuscular excitability properties. Further, all these training‐induced benefits were quantitatively and qualitatively related to the specific characteristics of each exercise, suggesting that the related neuroprotection is strongly dependent on the specific activation of some motor neuron subpopulations. Taken together, the present data show significant long‐term exercise benefits in type 3 SMA‐like mice providing important clues for designing rehabilitation programmes in patients. PMID:26915343

Physiological adaptations to low-volume, high-intensity interval training in health and disease.

PubMed

Gibala, Martin J; Little, Jonathan P; Macdonald, Maureen J; Hawley, John A

2012-03-01

Exercise training is a clinically proven, cost-effective, primary intervention that delays and in many cases prevents the health burdens associated with many chronic diseases. However, the precise type and dose of exercise needed to accrue health benefits is a contentious issue with no clear consensus recommendations for the prevention of inactivity-related disorders and chronic diseases. A growing body of evidence demonstrates that high-intensity interval training (HIT) can serve as an effective alternate to traditional endurance-based training, inducing similar or even superior physiological adaptations in healthy individuals and diseased populations, at least when compared on a matched-work basis. While less well studied, low-volume HIT can also stimulate physiological remodelling comparable to moderate-intensity continuous training despite a substantially lower time commitment and reduced total exercise volume. Such findings are important given that 'lack of time' remains the most commonly cited barrier to regular exercise participation. Here we review some of the mechanisms responsible for improved skeletal muscle metabolic control and changes in cardiovascular function in response to low-volume HIT. We also consider the limited evidence regarding the potential application of HIT to people with, or at risk for, cardiometabolic disorders including type 2 diabetes. Finally, we provide insight on the utility of low-volume HIT for improving performance in athletes and highlight suggestions for future research.

Exercise as a countermeasure for physiological adaptation to prolonged spaceflight

NASA Technical Reports Server (NTRS)

Convertino, V. A.

1996-01-01

Exercise represents the primary countermeasure used during spaceflight to maintain or restore maximal aerobic capacity (VO2max), musculoskeletal structure, and orthostatic function. However, no single exercise or combination of prescriptions has proven entirely effective in restoring cardiovascular and musculoskeletal functions to preflight levels following prolonged spaceflight. As human spaceflight exposures increase in duration, assessment and development of various effective exercise-based protective procedures become paramount. This must involve improvement in specific countermeasure prescription as well as development of additional approaches that will allow space travelers greater flexibility and medical safety during long flights. Effective exercise prescription will be based on identification of basic physiological stimuli that maintain normal function in terrestrial gravity and understanding of how specific combinations of exercise characteristics e.g., duration, frequency, intensity, mode) can mimic these stimuli and affect the overall process of adaptation to microgravity. This can be accomplished only with greater emphasis of research on ground-based experiments. Future attention must be directed to improving exercise compliance while minimizing both crew time and the impact of the exercise on life-support resources.

Long-term exercise-specific neuroprotection in spinal muscular atrophy-like mice.

PubMed

Chali, Farah; Desseille, Céline; Houdebine, Léo; Benoit, Evelyne; Rouquet, Thaïs; Bariohay, Bruno; Lopes, Philippe; Branchu, Julien; Della Gaspera, Bruno; Pariset, Claude; Chanoine, Christophe; Charbonnier, Frédéric; Biondi, Olivier

2016-04-01

The real impact of physical exercise parameters, i.e. intensity, type of contraction and solicited energetic metabolism, on neuroprotection in the specific context of neurodegeneration remains poorly explored. In this study behavioural, biochemical and cellular analyses were conducted to compare the effects of two different long-term exercise protocols, high intensity swimming and low intensity running, on motor units of a type 3 spinal muscular atrophy (SMA)-like mouse model. Our data revealed a preferential SMA-induced death of intermediate and fast motor neurons which was limited by the swimming protocol only, suggesting a close relationship between neuron-specific protection and their activation levels by specific exercise. The exercise-induced neuroprotection was independent of SMN protein expression and associated with specific metabolic and behavioural adaptations with notably a swimming-induced reduction of muscle fatigability. Our results provide new insight into the motor units' adaptations to different physical exercise parameters and will contribute to the design of new active physiotherapy protocols for patient care. Spinal muscular atrophy (SMA) is a group of autosomal recessive neurodegenerative diseases differing in their clinical outcome, characterized by the specific loss of spinal motor neurons, caused by insufficient level of expression of the protein survival of motor neuron (SMN). No cure is at present available for SMA. While physical exercise might represent a promising approach for alleviating SMA symptoms, the lack of data dealing with the effects of different exercise types on diseased motor units still precludes the use of active physiotherapy in SMA patients. In the present study, we have evaluated the efficiency of two long-term physical exercise paradigms, based on either high intensity swimming or low intensity running, in alleviating SMA symptoms in a mild type 3 SMA-like mouse model. We found that 10 months' physical training induced significant benefits in terms of resistance to muscle damage, energetic metabolism, muscle fatigue and motor behaviour. Both exercise types significantly enhanced motor neuron survival, independently of SMN expression, leading to the maintenance of neuromuscular junctions and skeletal muscle phenotypes, particularly in the soleus, plantaris and tibialis of trained mice. Most importantly, both exercises significantly improved neuromuscular excitability properties. Further, all these training-induced benefits were quantitatively and qualitatively related to the specific characteristics of each exercise, suggesting that the related neuroprotection is strongly dependent on the specific activation of some motor neuron subpopulations. Taken together, the present data show significant long-term exercise benefits in type 3 SMA-like mice providing important clues for designing rehabilitation programmes in patients. © 2016 The Authors. The Journal of Physiology © 2016 The Physiological Society.

Acute molecular responses to concurrent resistance and high-intensity interval exercise in untrained skeletal muscle

PubMed Central

Pugh, Jamie K; Faulkner, Steve H; Jackson, Andrew P; King, James A; Nimmo, Myra A

2015-01-01

Concurrent training involving resistance and endurance exercise may augment the benefits of single-mode training for the purpose of improving health. However, muscle adaptations, associated with resistance exercise, may be blunted by a subsequent bout of endurance exercise, via molecular interference. High-intensity interval training (HIIT), generating similar adaptations to endurance exercise, may offer an alternative exercise mode to traditional endurance exercise. This study examined the influence of an acute HIIT session on the molecular responses following resistance exercise in untrained skeletal muscle. Ten male participants performed resistance exercise (4 × 8 leg extensions, 70% 1RM, (RE)) or RE followed by HIIT (10 × 1 min at 90% HRmax, (RE+HIIT)). Muscle biopsies were collected from the vastus lateralis before, 2 and 6 h post-RE to determine intramuscular protein phosphorylation and mRNA responses. Phosphorylation of Akt (Ser473) decreased at 6 h in both trials (P < 0.05). Phosphorylation of mTOR (Ser2448) was higher in RE+HIIT (P < 0.05). All PGC-1α mRNA variants increased at 2 h in RE+HIIT with PGC-1α and PGC-1α-ex1b remaining elevated at 6 h, whereas RE-induced increases at 2 and 6 h for PGC-1α-ex1b only (P < 0.05). Myostatin expression decreased at 2 and 6 h in both trials (P < 0.05). MuRF-1 was elevated in RE+HIIT versus RE at 2 and 6 h (P < 0.05). Atrogin-1 was lower at 2 h, with FOXO3A downregulated at 6 h (P < 0.05). These data do not support the existence of an acute interference effect on protein signaling and mRNA expression, and suggest that HIIT may be an alternative to endurance exercise when performed after resistance exercise in the same training session to optimize adaptations. PMID:25902785

Circulating adiponectin concentration and body composition are altered in response to high-intensity interval training.

PubMed

Shing, Cecilia M; Webb, Jessica J; Driller, Matthew W; Williams, Andrew D; Fell, James W

2013-08-01

Adiponectin influences metabolic adaptations that would prove beneficial to endurance athletes, and yet to date there is little known about the response of adiponectin concentrations to exercise, and, in particular, the response of this hormone to training in an athlete population. This study aimed to determine the response of plasma adiponectin concentrations to acute exercise after 2 different training programs and to determine the influence of the training on body composition. Seven state-level representative rowers (age: 19 ± 1.2 years [mean ± SD], height: 1.77 ± 0.10 m, body mass: 74.0 ± 10.7 kg, VO2peak 62.1 ± 7.0 ml·kg·min) participated in the double-blind, randomized crossover investigation. Rowers performed an incremental graded exercise test before and after completing 4 weeks of high-intensity interval ergometer training and 4 weeks of traditional ergometer rowing training. Rowers' body composition was assessed at baseline and after each training program. Significant increases in plasma adiponectin concentration occurred in response to maximal exercise after completion of the high-intensity interval training (p = 0.016) but not after traditional ergometer rowing training (p = 0.69). The high-intensity interval training also resulted in significant increases in mean 4-minute power output (p = 0.002) and VO2peak (p = 0.05), and a decrease in body fat percentage (p = 0.022). Mean 4-minute power output, VO2peak, and body fat percentage were not significantly different after 4 weeks of traditional ergometer rowing training (p > 0.05). Four weeks of high-intensity interval training is associated with an increase in adiponectin concentration in response to maximal exercise and a reduction in body fat percentage. The potential for changes in adiponectin concentration to reflect positive training adaptations and athlete performance level should be further explored.

Impact of ethnicity on cardiac adaptation to exercise.

PubMed

Sheikh, Nabeel; Sharma, Sanjay

2014-04-01

The increasing globalization of sport has resulted in athletes from a wide range of ethnicities emerging onto the world stage. Fuelled by the untimely death of a number of young professional athletes, data generated from the parallel increase in preparticipation cardiovascular evaluation has indicated that ethnicity has a substantial influence on cardiac adaptation to exercise. From this perspective, the group most intensively studied comprises athletes of African or Afro-Caribbean ethnicity (black athletes), an ever-increasing number of whom are competing at the highest levels of sport and who often exhibit profound electrical and structural cardiac changes in response to exercise. Data on other ethnic cohorts are emerging, but remain incomplete. This Review describes our current knowledge on the impact of ethnicity on cardiac adaptation to exercise, starting with white athletes in whom the physiological electrical and structural changes--collectively termed the 'athlete's heart'--were first described. Discussion of the differences in the cardiac changes between ethnicities, with a focus on black athletes, and of the challenges that these variations can produce for the evaluating physician is also provided. The impact of ethnically mediated changes on preparticipation cardiovascular evaluation is highlighted, particularly with respect to false positive results, and potential genetic mechanisms underlying racial differences in cardiac adaptation to exercise are described.

Increasing skeletal muscle carnitine availability does not alter the adaptations to high-intensity interval training.

PubMed

Shannon, Christopher E; Ghasemi, Reza; Greenhaff, Paul L; Stephens, Francis B

2018-01-01

Increasing skeletal muscle carnitine availability alters muscle metabolism during steady-state exercise in healthy humans. We investigated whether elevating muscle carnitine, and thereby the acetyl-group buffering capacity, altered the metabolic and physiological adaptations to 24 weeks of high-intensity interval training (HIIT) at 100% maximal exercise capacity (Watt max ). Twenty-one healthy male volunteers (age 23±2 years; BMI 24.2±1.1 kg/m 2 ) performed 2 × 3 minute bouts of cycling exercise at 100% Watt max , separated by 5 minutes of rest. Fourteen volunteers repeated this protocol following 24 weeks of HIIT and twice-daily consumption of 80 g carbohydrate (CON) or 3 g l-carnitine+carbohydrate (CARN). Before HIIT, muscle phosphocreatine (PCr) degradation (P<.0001), glycogenolysis (P<.0005), PDC activation (P<.05), and acetylcarnitine (P<.005) were 2.3-, 2.1-, 1.5-, and 1.5-fold greater, respectively, in exercise bout two compared to bout 1, while lactate accumulation tended (P<.07) to be 1.5-fold greater. Following HIIT, muscle free carnitine was 30% greater in CARN vs CON at rest and remained 40% elevated prior to the start of bout 2 (P<.05). Following bout 2, free carnitine content, PCr degradation, glycogenolysis, lactate accumulation, and PDC activation were all similar between CON and CARN, albeit markedly lower than before HIIT. VO 2max , Watt max , and work output were similarly increased in CON and CARN, by 9, 15, and 23% (P<.001). In summary, increased reliance on non-mitochondrial ATP resynthesis during a second bout of intense exercise is accompanied by increased carnitine acetylation. Augmenting muscle carnitine during 24 weeks of HIIT did not alter this, nor did it enhance muscle metabolic adaptations or performance gains beyond those with HIIT alone. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Effect of 24 sessions of high-intensity aerobic interval training carried out at either high or moderate frequency, a randomized trial.

PubMed

Hatle, Håvard; Støbakk, Per Kristian; Mølmen, Harald Edvard; Brønstad, Eivind; Tjønna, Arnt Erik; Steinshamn, Sigurd; Skogvoll, Eirik; Wisløff, Ulrik; Ingul, Charlotte Björk; Rognmo, Øivind

2014-01-01

The training response of an intensified period of high-intensity exercise is not clear. Therefore, we compared the cardiovascular adaptations of completing 24 high-intensity aerobic interval training sessions carried out for either three or eight weeks, respectively. Twenty-one healthy subjects (23.0±2.1 years, 10 females) completed 24 high-intensity training sessions throughout a time-period of either eight weeks (moderate frequency, MF) or three weeks (high frequency, HF) followed by a detraining period of nine weeks without any training. In both groups, maximal oxygen uptake (VO2max) was evaluated before training, at the 9(th) and 17(th) session and four days after the final 24(th) training session. In the detraining phase VO2max was evaluated after 12 days and thereafter every second week for eight weeks. Left ventricular echocardiography, carbon monoxide lung diffusion transfer factor, brachial artery flow mediated dilatation and vastus lateralis citrate maximal synthase activity was tested before and after training. The cardiovascular adaptation after HF training was delayed compared to training with MF. Four days after ending training the HF group showed no improvement (+3.0%, p = 0.126), whereas the MF group reached their highest VO2max with a 10.7% improvement (p<0.001: group difference p = 0.035). The HF group reached their highest VO2max (6.1% increase, p = 0.026) twelve days into the detraining period, compared to a concomitant reduction to 7.9% of VO2max (p<0.001) above baseline in the MF group (group difference p = 0.609). Both HF and MF training of high-intensity aerobic exercise improves VO2max. The cardiovascular adaptation following a HF programme of high-intensity exercise is however delayed compared to MF training. ClinicalTrials.gov NCT00733941.

Cardiovascular adaptations supporting human exercise-heat acclimation.

PubMed

Périard, Julien D; Travers, Gavin J S; Racinais, Sébastien; Sawka, Michael N

2016-04-01

This review examines the cardiovascular adaptations along with total body water and plasma volume adjustments that occur in parallel with improved heat loss responses during exercise-heat acclimation. The cardiovascular system is well recognized as an important contributor to exercise-heat acclimation that acts to minimize physiological strain, reduce the risk of serious heat illness and better sustain exercise capacity. The upright posture adopted by humans during most physical activities and the large skin surface area contribute to the circulatory and blood pressure regulation challenge of simultaneously supporting skeletal muscle blood flow and dissipating heat via increased skin blood flow and sweat secretion during exercise-heat stress. Although it was traditionally held that cardiac output increased during exercise-heat stress to primarily support elevated skin blood flow requirements, recent evidence suggests that temperature-sensitive mechanisms may also mediate an elevation in skeletal muscle blood flow. The cardiovascular adaptations supporting this challenge include an increase in total body water, plasma volume expansion, better sustainment and/or elevation of stroke volume, reduction in heart rate, improvement in ventricular filling and myocardial efficiency, and enhanced skin blood flow and sweating responses. The magnitude of these adaptations is variable and dependent on several factors such as exercise intensity, duration of exposure, frequency and total number of exposures, as well as the environmental conditions (i.e. dry or humid heat) in which acclimation occurs. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Effect of moderate- and high-intensity acute exercise on appetite in obese individuals.

PubMed

Martins, Catia; Stensvold, Dorthe; Finlayson, Graham; Holst, Jens; Wisloff, Ulrik; Kulseng, Bård; Morgan, Linda; King, Neil A

2015-01-01

The effect of acute exercise, and exercise intensity, on appetite control in obese individuals requires further study. The aim of this study was to compare the effects of acute isocaloric bouts (250 kcal) of high-intensity intermittent cycling (HIIC) and moderate-intensity continuous cycling (MICC) or short-duration HIIC (S-HIIC) (125 kcal) and a resting control condition on the appetite hormone responses, subjective feelings of appetite, energy intake (EI), and food reward in overweight/obese individuals. This study is a randomized crossover study on 12 overweight/obese volunteers. Participants were assigned to the control, MICC, HIIC, and S-HIIC conditions, 1 wk apart, in a counterbalanced order. Exercise was performed 1 h after a standard breakfast. An ad libitum test lunch was served 3 h after breakfast. Fasting/postprandial plasma samples of insulin, acylated ghrelin, polypeptide YY3-36, and glucagon-like peptide 1 and subjective feelings of appetite were measured every 30 min for 3 h. Nutrient and taste preferences were measured at the beginning and end of each condition using the Leeds Food Preference Questionnaire. Insulin levels were significantly reduced, and glucagon-like peptide 1 levels significantly increased during all exercise bouts compared with those during rest. Acylated ghrelin plasma levels were lower in the MICC and HIIC, but not in S-HIIC, compared with those in control. There were no significant differences for polypeptide YY3-36 plasma levels, hunger or fullness ratings, EI, or food reward. Our findings suggest that, in overweight/obese individuals, isocaloric bouts of moderate- or high-intensity exercise lead to a similar appetite response. This strengthens previous findings in normal-weight individuals that acute exercise, even at high intensity, does not induce any known physiological adaptation that would lead to increased EI.

Is high-intensity interval training a time-efficient exercise strategy to improve health and fitness?

PubMed

Gillen, Jenna B; Gibala, Martin J

2014-03-01

Growing research suggests that high-intensity interval training (HIIT) is a time-efficient exercise strategy to improve cardiorespiratory and metabolic health. "All out" HIIT models such as Wingate-type exercise are particularly effective, but this type of training may not be safe, tolerable or practical for many individuals. Recent studies, however, have revealed the potential for other models of HIIT, which may be more feasible but are still time-efficient, to stimulate adaptations similar to more demanding low-volume HIIT models and high-volume endurance-type training. As little as 3 HIIT sessions per week, involving ≤10 min of intense exercise within a time commitment of ≤30 min per session, including warm-up, recovery between intervals and cool down, has been shown to improve aerobic capacity, skeletal muscle oxidative capacity, exercise tolerance and markers of disease risk after only a few weeks in both healthy individuals and people with cardiometabolic disorders. Additional research is warranted, as studies conducted have been relatively short-term, with a limited number of measurements performed on small groups of subjects. However, given that "lack of time" remains one of the most commonly cited barriers to regular exercise participation, low-volume HIIT is a time-efficient exercise strategy that warrants consideration by health practitioners and fitness professionals.

A Carbohydrate Ingestion Intervention in an Elite Athlete Who Follows a LCHF Diet.

PubMed

Webster, Christopher C; Swart, Jeroen; Noakes, Timothy D; Smith, James A

2017-12-18

This case study documents the performance of an elite-level, exceptionally well fat-adapted endurance athlete, as he reintroduced carbohydrate ingestion during high-intensity training. He had followed a strict low-carbohydrate high-fat (LCHF) diet for 2 years during which he ate approximately 80 g of carbohydrate per day and trained and raced while ingesting only water. While following this diet, he earned numerous podium finishes in triathlons of various distances. However, he approached us to test whether carbohydrate supplementation during exercise would further increase his high-intensity performance without affecting his fat-adaptation. This 7-week n=1 investigation included a 4-week habitual LCHF diet phase (LCHF) during which he drank only water during training and performance trials, and a 3-week habitual diet plus carbohydrate ingestion phase (LCHF+CHO), during which he followed his usual LCHF diet but ingested 60 g/h carbohydrate during 8 high-intensity training sessions and performance trials. After each phase, rates of fat oxidation and 30 s sprint, 4 min sprint, 20 km time trial (TT), and 100 km TT performances were measured. Compared to LCHF, 20 km TT time improved by 2.8 % after LCHF+CHO, which would be a large difference in competition. There was no change in 30 s sprint power; a small improvement in 4 min sprint power (1.6 %); and a small reduction in 100 km TT time (1.1%). We conclude that carbohydrate ingestion during exercise was likely beneficial for this fat-adapted athlete during high-intensity endurance-type exercise (4-30 min) but likely did not benefit his short sprint or prolonged endurance performance.

Global Metabolic Stress of Isoeffort Continuous and High Intensity Interval Aerobic Exercise: A Comparative 1H NMR Metabonomic Study.

PubMed

Zafeiridis, Andreas; Chatziioannou, Anastasia Chrysovalantou; Sarivasiliou, Haralambos; Kyparos, Antonios; Nikolaidis, Michalis G; Vrabas, Ioannis S; Pechlivanis, Alexandros; Zoumpoulakis, Panagiotis; Baskakis, Constantinos; Dipla, Konstantina; Theodoridis, Georgios A

2016-12-02

The overall metabolic/energetic stress that occurs during an acute bout of exercise is proposed to be the main driving force for long-term training adaptations. Continuous and high-intensity interval exercise protocols (HIIE) are currently prescribed to acquire the muscular and metabolic benefits of aerobic training. We applied 1 H NMR-based metabonomics to compare the overall metabolic perturbation and activation of individual bioenergetic pathways of three popular aerobic exercises matched for effort/strain. Nine men performed continuous, long-interval (3 min), and short-interval (30 s) bouts of exercise under isoeffort conditions. Blood was collected before and after exercise. The multivariate PCA and OPLS-DA models showed a distinct separation of pre- and postexercise samples in three protocols. The two models did not discriminate the postexercise overall metabolic profiles of the three exercise types. Analysis focused on muscle bioenergetic pathways revealed an extensive upregulation of carbohydrate-lipid metabolism and the TCA cycle in all three protocols; there were only a few differences among protocols in the postexercise abundance of molecules when long-interval bouts were performed. In conclusion, continuous and HIIE exercise protocols, when performed with similar effort/strain, induce comparable global metabolic response/stress despite their marked differences in work-bout intensities. This study highlights the importance of NMR metabonomics in comprehensive monitoring of metabolic consequences of exercise training in the blood of athletes and exercising individuals.

A scoping review of the psychological responses to interval exercise: is interval exercise a viable alternative to traditional exercise?

PubMed

Stork, Matthew J; Banfield, Laura E; Gibala, Martin J; Martin Ginis, Kathleen A

2017-12-01

While considerable evidence suggests that interval exercise confers numerous physiological adaptations linked to improved health, its psychological consequences and behavioural implications are less clear and the subject of intense debate. The purpose of this scoping review was to catalogue studies investigating the psychological responses to interval exercise in order to identify what psychological outcomes have been assessed, the research methods used, and the results. A secondary objective was to identify research issues and gaps. Forty-two published articles met the review inclusion/exclusion criteria. These studies involved 1258 participants drawn from various active/inactive and healthy/unhealthy populations, and 55 interval exercise protocols (69% high-intensity interval training [HIIT], 27% sprint interval training [SIT], and 4% body-weight interval training [BWIT]). Affect and enjoyment were the most frequently studied psychological outcomes. Post-exercise assessments indicate that overall, enjoyment of, and preferences for interval exercise are equal or greater than for continuous exercise, and participants can hold relatively positive social cognitions regarding interval exercise. Although several methodological issues (e.g., inconsistent use of terminology, measures and protocols) and gaps (e.g., data on adherence and real-world protocols) require attention, from a psychological perspective, the emerging data support the viability of interval exercise as an alternative to continuous exercise.

Combined Interval Training and Post-exercise Nutrition in Type 2 Diabetes: A Randomized Control Trial.

PubMed

Francois, Monique E; Durrer, Cody; Pistawka, Kevin J; Halperin, Frank A; Chang, Courtney; Little, Jonathan P

2017-01-01

Background: High-intensity interval training (HIIT) can improve several aspects of cardiometabolic health. Previous studies have suggested that adaptations to exercise training can be augmented with post-exercise milk or protein consumption, but whether this nutritional strategy can impact the cardiometabolic adaptations to HIIT in type 2 diabetes is unknown. Objective: To determine if the addition of a post-exercise milk or protein beverage to a high-intensity interval training (HIIT) intervention improves cardiometabolic health in individuals with type 2 diabetes. Design: In a proof-of-concept, double-blind clinical trial 53 adults with uncomplicated type 2 diabetes were randomized to one of three nutritional beverages (500 mL skim-milk, macronutrient control, or flavored water placebo) consumed after exercise (3 days/week) during a 12 week low-volume HIIT intervention. HIIT involved 10 X 1-min high-intensity intervals separated by 1-min low-intensity recovery periods. Two sessions per week were cardio-based (at ~90% of heart rate max) and one session involved resistance-based exercises (at RPE of 5-6; CR-10 scale) in the same interval pattern. Continuous glucose monitoring (CGM), glycosylated hemoglobin (HbA 1c ), body composition (dual-energy X-ray absorptiometry), cardiorespiratory fitness ([Formula: see text]), blood pressure, and endothelial function (%FMD) were measured before and after the intervention. Results: There were significant main effects of time (all p < 0.05) but no difference between groups (Interaction: all p > 0.71) for CGM 24-h mean glucose (-0.5 ± 1.1 mmol/L), HbA 1c (-0.2 ± 0.4%), percent body fat (-0.8 ± 1.6%), and lean mass (+1.1 ± 2.8 kg). Similarly, [Formula: see text] (+2.5 ± 1.6 mL/kg/min) and %FMD (+1.4 ± 1.9%) were increased, and mean arterial blood pressure reduced (-6 ± 7 mmHg), after 12 weeks of HIIT (all p < 0.01) with no difference between beverage groups (Interaction: all p > 0.11). Conclusion: High-intensity interval training is a potent stimulus for improving several important metabolic and cardiovascular risk factors in type 2 diabetes. The benefits of HIIT are not augmented by the addition of post-exercise protein.

Combined Interval Training and Post-exercise Nutrition in Type 2 Diabetes: A Randomized Control Trial

PubMed Central

Francois, Monique E.; Durrer, Cody; Pistawka, Kevin J.; Halperin, Frank A.; Chang, Courtney; Little, Jonathan P.

2017-01-01

Background: High-intensity interval training (HIIT) can improve several aspects of cardiometabolic health. Previous studies have suggested that adaptations to exercise training can be augmented with post-exercise milk or protein consumption, but whether this nutritional strategy can impact the cardiometabolic adaptations to HIIT in type 2 diabetes is unknown. Objective: To determine if the addition of a post-exercise milk or protein beverage to a high-intensity interval training (HIIT) intervention improves cardiometabolic health in individuals with type 2 diabetes. Design: In a proof-of-concept, double-blind clinical trial 53 adults with uncomplicated type 2 diabetes were randomized to one of three nutritional beverages (500 mL skim-milk, macronutrient control, or flavored water placebo) consumed after exercise (3 days/week) during a 12 week low-volume HIIT intervention. HIIT involved 10 X 1-min high-intensity intervals separated by 1-min low-intensity recovery periods. Two sessions per week were cardio-based (at ~90% of heart rate max) and one session involved resistance-based exercises (at RPE of 5–6; CR-10 scale) in the same interval pattern. Continuous glucose monitoring (CGM), glycosylated hemoglobin (HbA1c), body composition (dual-energy X-ray absorptiometry), cardiorespiratory fitness (V˙O2peak), blood pressure, and endothelial function (%FMD) were measured before and after the intervention. Results: There were significant main effects of time (all p < 0.05) but no difference between groups (Interaction: all p > 0.71) for CGM 24-h mean glucose (−0.5 ± 1.1 mmol/L), HbA1c (−0.2 ± 0.4%), percent body fat (−0.8 ± 1.6%), and lean mass (+1.1 ± 2.8 kg). Similarly, V˙O2peak (+2.5 ± 1.6 mL/kg/min) and %FMD (+1.4 ± 1.9%) were increased, and mean arterial blood pressure reduced (−6 ± 7 mmHg), after 12 weeks of HIIT (all p < 0.01) with no difference between beverage groups (Interaction: all p > 0.11). Conclusion: High-intensity interval training is a potent stimulus for improving several important metabolic and cardiovascular risk factors in type 2 diabetes. The benefits of HIIT are not augmented by the addition of post-exercise protein. PMID:28790929

High-Intensity Exercise as a Dishabituating Stimulus Restores Counterregulatory Responses in Recurrently Hypoglycemic Rodents.

PubMed

McNeilly, Alison D; Gallagher, Jennifer R; Huang, Jeffrey T-J; Ashford, Michael L J; McCrimmon, Rory J

2017-06-01

Hypoglycemia is a major adverse effect of insulin therapy for people with type 1 diabetes (T1D). Profound defects in the normal counterregulatory response to hypoglycemia explain the frequency of hypoglycemia occurrence in T1D. Defective counterregulation results to a large extent from prior exposure to hypoglycemia per se, leading to a condition called impaired awareness of hypoglycemia (IAH), the cause of which is unknown. In the current study, we investigate the hypothesis that IAH develops through a special type of adaptive memory referred to as habituation. To test this hypothesis, we used a novel intense stimulus (high-intensity exercise) to demonstrate two classic features of a habituated response, namely dishabituation and response recovery. We demonstrate that after recurrent hypoglycemia the introduction of a novel dishabituating stimulus (a single burst of high-intensity exercise) in male Sprague-Dawley rats restores the defective hypoglycemia counterregulatory response. In addition, the rats showed an enhanced response to the novel stimulus (response recovery). We make the further observation using proteomic analysis of hypothalamic extracts that high-intensity exercise in recurrently hypoglycemic rats increases levels of a number of proteins linked with brain-derived neurotrophic factor signaling. These findings may lead to novel therapeutic approaches for individuals with T1D and IAH. © 2017 by the American Diabetes Association.

Prevention: The Best Treatment for Back Pain

MedlinePlus

... you are re-starting an exercise routine , start low and slow. See how your body adapts before increasing time or intensity. If taking preventive measures do not prevent back pain, or an existing condition worsens, a visit to ...

NASA's Functional Task Test: High Intensity Exercise Improves the Heart Rate Response to a Stand Test Following 70 Days of Bedrest

NASA Technical Reports Server (NTRS)

Laurie, Steven S.; Lee, Stuart M. C.; Phillips, Tiffany R.; Dillon, E. Lichar; Sheffield-Moore, Melinda; Urban, Randall J.; Ploutz-Snyder, Lori; Stenger, Michael B.; Bloomberg, Jacob J.

2015-01-01

Cardiovascular adaptations due to spaceflight are modeled with 6deg head-down tilt bed rest (BR) and result in decreased orthostatic tolerance. We investigated if high-intensity resistive and aerobic exercise with and without testosterone supplementation would improve the heart rate (HR) response to a 3.5-min stand test and how quickly these changes recovered following BR. During 70 days of BR male subjects performed no exercise (Control, n=10), high intensity supine resistive and aerobic exercise (Exercise, n=9), or supine exercise plus supplemental testosterone (Exercise+T, n=8; 100 mg i.m., weekly in 2-week on/off cycles). We measured HR for 2 min while subjects were prone and for 3 min after standing twice before and 0, 1, 6, and 11 days after BR. Mixed-effects linear regression models were used to evaluate group, time, and interaction effects. Compared to pre-bed rest, prone HR was elevated on BR+0 and BR+1 in Control, but not Exercise or Exercise+T groups, and standing HR was greater in all 3 groups. The increase in prone and standing HR in Control subjects was greater than either Exercise or Exercise+T groups and all groups recovered by BR+6. The change in HR from prone to standing more than doubled on BR+0 in all groups, but was significantly less in the Exericse+T group compared to the Control, but not Exercise group. Exercise reduces, but does not prevent the increase in HR observed in response to standing. The significantly lower HR response in the Exercise+T group requires further investigation to determine physiologic significance.

Nutrition for power sports: middle-distance running, track cycling, rowing, canoeing/kayaking, and swimming.

PubMed

Stellingwerff, Trent; Maughan, Ronald J; Burke, Louise M

2011-01-01

Contemporary training for power sports involves diverse routines that place a wide array of physiological demands on the athlete. This requires a multi-faceted nutritional strategy to support both general training needs--tailored to specific training phases--as well as the acute demands of competition. Elite power sport athletes have high training intensities and volumes for most of the training season, so energy intake must be sufficient to support recovery and adaptation. Low pre-exercise muscle glycogen reduces high-intensity performance, so daily carbohydrate intake must be emphasized throughout training and competition phases. There is strong evidence to suggest that the timing, type, and amount of protein intake influence post-exercise recovery and adaptation. Most power sports feature demanding competition schedules, which require aggressive nutritional recovery strategies to optimize muscle glycogen resynthesis. Various power sports have different optimum body compositions and body weight requirements, but increasing the power-to-weight ratio during the championship season can lead to significant performance benefits for most athletes. Both intra- and extracellular buffering agents may enhance performance, but more research is needed to examine the potential long-term impact of buffering agents on training adaptation. Interactions between training, desired physiological adaptations, competition, and nutrition require an individual approach and should be continuously adjusted and adapted.

Electromyographic Activity of Scapular Muscle Control in Free-Motion Exercise

PubMed Central

Nakamura, Yukiko; Tsuruike, Masaaki; Ellenbecker, Todd S.

2016-01-01

Context:  The appropriate resistance intensity to prescribe for shoulder rehabilitative exercise is not completely known. Excessive activation of the deltoid and upper trapezius muscles could be counterproductive for scapulohumeral rhythm during humeral elevation. Objective:  To identify the effects of different exercise intensities on the scapular muscles during a free-motion “robbery” exercise performed in different degrees of shoulder abduction in seated and standing positions. Design:  Descriptive laboratory study. Setting:  Kinesiology Adapted Physical Education Laboratory. Patients or Other Participants:  A total of 15 healthy male college students (age = 20.5 ± 2.2 years, height = 174.5 ± 5.3 cm, mass = 63.8 ± 6.0 kg). Intervention(s):  Participants performed 5 repetitions of a randomized exercise sequence of the robbery exercise in 2 body positions (seated, standing), 2 shoulder-abducted positions (W [20°], 90/90 [90°]) at 3 intensities (0%, 3%, and 7% body weight). Main Outcome Measure(s):  Electromyographic (EMG) activity of the upper trapezius, lower trapezius, serratus anterior, anterior deltoid, and infraspinatus muscles of the upper extremity was collected. All EMG activities were normalized by the maximal voluntary isometric contraction of each corresponding muscle (%). Results:  The serratus anterior, anterior deltoid, and infraspinatus EMG activities were greater at 7% body weight in the seated position compared with the standing position (P < .05). The EMG activities in all 5 muscles were greater in the 90/90 position than in the W position (P < .05). Conclusions:  Scapular muscle activity modulated relative to changes in body posture and resistance intensity. These findings will enable clinicians to prescribe the appropriate level of exercise intensity and positioning during shoulder rehabilitation. PMID:26986055

Endocrinology and Pediatric Exercise Science-2016.

PubMed

Eliakim, Alon

2017-02-01

The Pediatric Exercise Science Year That Was section aims to highlight the most important (to the author's opinion) manuscripts that were published in 2016 in the field of endocrinology and pediatric exercise science. This year's selection includes studies showing that 1) Induction of T4 to T3 conversion by type 2 deiodinase following aerobic exercise in skeletal muscles was associated with concomitant increase in peroxisome proliferatoractivated receptor-γ coactivator-1α, and mitochondrial oxidative capacity and therefore plays an important mechanistic role in the muscle adaptation to exercise training. 2) Hypothyroidism in fetal and early postnatal life was associated with impaired spatial learning and memory and with reduced hippocampal brain-derived neurotrophic factor in male and female rat pups. Forced (treadmill) and voluntary (wheel) exercise alleviated all these biochemical and neuro-cognitive deficits. 3) The relationship between different exercise intensities and carbohydrate requirements to maintain euglycemia at basal insulin levels among adolescent and young adults with Type 1 diabetes are nonlinear but rather inverted- U with no exogenous glucose required to maintain stable glucose level at high-intensity exercise (80%). The implication of these studies to the pediatric population, their importance and the new research avenues that were opened by these studies is emphasized.

The respiration pattern as an indicator of the anaerobic threshold.

PubMed

Mirmohamadsadeghi, Leila; Vesin, Jean-Marc; Lemay, Mathieu; Deriaz, Olivier

2015-08-01

The anaerobic threshold (AT) is a good index of personal endurance but needs a laboratory setting to be determined. It is important to develop easy AT field measurements techniques in order to rapidly adapt training programs. In the present study, it is postulated that the variability of the respiratory parameters decreases with exercise intensity (especially at the AT level). The aim of this work was to assess, on healthy trained subjects, the putative relationships between the variability of some respiration parameters and the AT. The heart rate and respiratory variables (volume, rate) were measured during an incremental exercise performed on a treadmill by healthy moderately trained subjects. Results show a decrease in the variance of 1/tidal volume with the intensity of exercise. Consequently, the cumulated variance (sum of the variance measured at each level of the exercise) follows an exponential relationship with respect to the intensity to reach eventually a plateau. The amplitude of this plateau is closely related to the AT (r=-0.8). It is concluded that the AT is related to the variability of the respiration.

Development of an Individualized Yoga Intervention to Address Fatigue in Hospitalized Children Undergoing Intensive Chemotherapy.

PubMed

Diorio, Caroline; Celis Ekstrand, Amanda; Hesser, Tanya; O'Sullivan, Cathy; Lee, Michelle; Schechter, Tal; Sung, Lillian

2016-09-01

Purpose Fatigue is an important problem in children receiving intensive chemotherapy and hematopoietic stem cell transplantation (HSCT). Exercise may be an effective intervention for fatigue. Individualized yoga represents an ideal intervention because it can be tailored according to an individual child's needs. Little is known about how to structure a standardized yoga program for intensivelytreated children. Therefore, this study describes the development of a yoga program and an approach to monitoring sessions suitable for hospitalized children receiving intensive chemotherapy or HSCT. Methods The yoga program was designed to increase mobility in hospitalized children and to provide children with relaxation techniques that could be used independently in a variety of environments. The program was founded on 4 key tenets: safety, adaptability, environmental flexibility, and appeal to children. We also developed quality and consistency assurance procedures. Results A menu format with a fixed structure was selected for the yoga program. Each yoga session contained up to 6 sections: breathing exercises, warmup exercises, yoga poses, balancing poses, cool-down poses, and final relaxation. Yoga instructors selected specific yoga poses for each session from a predetermined list organized by intensity level (low, moderate, or high). Monitoring procedures were developed using videotaping and multirater adjudication. Conclusion We created a standardized yoga program and an approach to monitoring that are now ready for incorporation in clinical trials. Future work should include the adaptation of the program to different pediatric populations and clinical settings. © The Author(s) 2016.

Training effects on ROS production determined by electron paramagnetic resonance in master swimmers.

PubMed

Mrakic-Sposta, Simona; Gussoni, Maristella; Porcelli, Simone; Pugliese, Lorenzo; Pavei, Gaspare; Bellistri, Giuseppe; Montorsi, Michela; Tacchini, Philippe; Vezzoli, Alessandra

2015-01-01

Acute exercise induces an increase in Reactive Oxygen Species (ROS) production dependent on exercise intensity with highest ROS amount generated by strenuous exercise. However, chronic repetition of exercise, that is, exercise training, may reduce exercise-induced oxidative stress. Aim of this study was to evaluate the effects of 6-weeks high-intensity discontinuous training (HIDT), characterized by repeated variations of intensity and changes of redox potential, on ROS production and antioxidant capacity in sixteen master swimmers. Time course changes of ROS generation were assessed by Electron Paramagnetic Resonance in capillary blood by a microinvasive approach. An incremental arm-ergometer exercise (IE) until exhaustion was carried out at both before (PRE) and after (POST) training (Trg) period. A significant (P < 0.01) increase of ROS production from REST to the END of IE in PRE Trg (2.82 ± 0.66 versus 3.28 ± 0.66 µmol·min(-1)) was observed. HIDT increased peak oxygen consumption (36.1 ± 4.3 versus 40.6 ± 5.7 mL·kg(-1)·min(-1) PRE and POST Trg, resp.) and the antioxidant capacity (+13%) while it significantly decreased the ROS production both at REST (-20%) and after IE (-25%). The observed link between ROS production, adaptive antioxidant defense mechanisms, and peak oxygen consumption provides new insight into the correlation between ROS response pathways and muscle metabolic function.

Simulated Partners and Collaborative Exercise (SPACE) to boost motivation for astronauts: study protocol.

PubMed

Feltz, Deborah L; Ploutz-Snyder, Lori; Winn, Brian; Kerr, Norbert L; Pivarnik, James M; Ede, Alison; Hill, Christopher; Samendinger, Stephen; Jeffery, William

2016-11-14

Astronauts may have difficulty adhering to exercise regimens at vigorous intensity levels during long space missions. Vigorous exercise is important for aerobic and musculoskeletal health during space missions and afterwards. A key impediment to maintaining vigorous exercise is motivation. Finding ways to motivate astronauts to exercise at levels necessary to mitigate reductions in musculoskeletal health and aerobic capacity have not been explored. The focus of Simulated Partners and Collaborative Exercise (SPACE) is to use recently documented motivation gains in task groups to heighten the exercise experience for participants, similar in age and fitness to astronauts, for vigorous exercise over a 6-month exercise regimen. A secondary focus is to determine the most effective features in simulated exercise partners for enhancing enjoyment, self-efficacy, and social connectedness. The aims of the project are to (1) Create software-generated (SG) exercise partners and interface software with a cycle ergometer; (2) Pilot test design features of SG partners within a video exercise game (exergame), and (3) Test whether exercising with an SG partner over 24-week time period, compared to exercising alone, leads to greater work effort, aerobic capacity, muscle strength, exercise adherence, and enhanced psychological parameters. This study was approved by the Institutional Review Board (IRB). Chronic exercisers, between the ages 30 and 62, were asked to exercise on a cycle ergometer 6 days per week for 24 weeks using a routine consisting of alternating between moderate-intensity continuous and high-intensity interval sessions. Participants were assigned to one of three conditions: no partner (control), always faster SG partner, or SG partner who was not always faster. Participants were told they could vary cycle ergometer output to increase or decrease intensity during the sessions. Mean change in cycle ergometer power (watts) from the initial continuous and 4 min. interval sessions was the primary dependent variable reflecting work effort. Measures of physiological, strength, and psychological parameters were also taken. This paper describes the rationale, development, and methods of the SPACE exergame. We believe this will be a viable intervention that can be disseminated for astronaut use and adapted for use by other populations.

How do cardiorespiratory fitness improvements vary with physical training modality in heart failure patients? A quantitative guide

PubMed Central

Smart, Neil A

2013-01-01

BACKGROUND: Peak oxygen consumption (VO2) is the gold standard measure of cardiorespiratory fitness and a reliable predictor of survival in chronic heart failure patients. Furthermore, any form of physical training usually improves cardiorespiratory fitness, although the magnitude of improvement in peak VO2 may vary across different training prescriptions. OBJECTIVE: To quantify, and subsequently rank, the magnitude of improvement in peak VO2 for different physical training prescriptions using data from published meta-analyses and randomized controlled trials. METHODS: Prospective randomized controlled parallel trials and meta-analyses of exercise training in chronic heart failure patients that provided data on change in peak VO2 for nine a priori comparative analyses were examined. RESULTS: All forms of physical training were beneficial, although the improvement in peak VO2 varied with modality. High-intensity interval exercise yielded the largest increase in peak VO2, followed in descending order by moderate-intensity aerobic exercise, functional electrical stimulation, inspiratory muscle training, combined aerobic and resistance training, and isolated resistance training. With regard to setting, the present study was unable to determine whether outpatient or unsupervised home exercise provided greater benefits in terms of peak VO2 improvment. CONCLUSIONS: Interval exercise is not suitable for all patients, especially the high-intensity variety; however, when indicated, this form of exercise should be adopted to optimize peak VO2 adaptations. Other forms of activity, such as functional electrical stimulation, may be more appropriate for patients who are not capable of high-intensity interval training, especially for severely deconditioned patients who are initially unable to exercise. PMID:24294043

Muscle intracellular oxygenation during exercise: optimization for oxygen transport, metabolism, and adaptive change.

PubMed

Wagner, Peter D

2012-01-01

Exercise is the example par excellence of the body functioning as a physiological system. Conventionally we think of the O(2) transport process as a major manifestation of that system linking and integrating pulmonary, cardiovascular, hematological and skeletal muscular contributions to the task of getting O(2) from the air to the mitochondria, and this process has been well described. However, exercise invokes system responses at levels additional to those of macroscopic O(2) transport. One such set of responses appears to center on muscle intracellular PO(2), which falls dramatically from rest to exercise. At rest, it approximates 4 kPa, but during heavy endurance exercise it falls to about 0.4-0.5 kPa, an amazingly low value for a tissue absolutely dependent on the continual supply of O(2) to meet very high energy demands. One wonders why intracellular PO(2) is allowed to fall to such levels. The proposed answer, to be presented in the review, is that a low intramyocyte PO(2) is pivotal in: (a) optimizing oxygen's own physiological transport, and (b) stimulating adaptive gene expression that, after translation, enables greater exercise capacity-all the while maintaining PO(2) at levels sufficient to allow oxidative phosphorylation to operate sufficiently fast enough to support intense muscle contraction. Thus, during exercise, reductions of intracellular PO(2) to less than 1% of that in the atmosphere enables an integrated response that fundamentally and simultaneously optimizes physiological, biochemical and molecular events that support not only the exercise as it happens but the adaptive changes to increase exercise capacity over the longer term.

Acute low-intensity cycling with blood-flow restriction has no effect on metabolic signaling in human skeletal muscle compared to traditional exercise.

PubMed

Smiles, William J; Conceição, Miguel S; Telles, Guilherme D; Chacon-Mikahil, Mara P T; Cavaglieri, Cláudia R; Vechin, Felipe C; Libardi, Cleiton A; Hawley, John A; Camera, Donny M

2017-02-01

Autophagy is an intracellular degradative system sensitive to hypoxia and exercise-induced perturbations to cellular bioenergetics. We determined the effects of low-intensity endurance-based exercise performed with blood-flow restriction (BFR) on cell signaling adaptive responses regulating autophagy and substrate metabolism in human skeletal muscle. In a randomized cross-over design, nine young, healthy but physically inactive males completed three experimental trials separated by 1 week of recovery consisting of either a resistance exercise bout (REX: 4 × 10 leg press repetitions, 70% 1-RM), endurance exercise (END: 30 min cycling, 70% VO 2peak ), or low-intensity cycling with BFR (15 min, 40% VO 2peak ). A resting muscle biopsy was obtained from the vastus lateralis 2 weeks prior to the first exercise trial and 3 h after each exercise bout. END increased ULK1 Ser757 phosphorylation above rest and BFR (~37 to 51%, P < 0.05). Following REX, there were significant elevations compared to rest (~348%) and BFR (~973%) for p38γ MAPK Thr180/Tyr182 phosphorylation (P < 0.05). Parkin content was lower following BFR cycling compared to REX (~20%, P < 0.05). There were no exercise-induced changes in select markers of autophagy following BFR. Genes implicated in substrate metabolism (HK2 and PDK4) were increased above rest (~143 to 338%) and BFR cycling (~212 to 517%) with END (P < 0.001). A single bout of low-intensity cycling with BFR is insufficient to induce intracellular "stress" responses (e.g., high rates of substrate turnover and local hypoxia) necessary to activate skeletal muscle autophagy signaling.

Power Relative to Body Mass Best Predicts Change in Core Temperature During Exercise-Heat Stress.

PubMed

Gibson, Oliver R; Willmott, Ashley G B; James, Carl A; Hayes, Mark; Maxwell, Neil S

2017-02-01

Gibson, OR, Willmott, AGB, James, CA, Hayes, M, and Maxwell, NS. Power relative to body mass best predicts change in core temperature during exercise-heat stress. J Strength Cond Res 31(2): 403-414, 2017-Controlling internal temperature is crucial when prescribing exercise-heat stress, particularly during interventions designed to induce thermoregulatory adaptations. This study aimed to determine the relationship between the rate of rectal temperature (Trec) increase, and various methods for prescribing exercise-heat stress, to identify the most efficient method of prescribing isothermic heat acclimation (HA) training. Thirty-five men cycled in hot conditions (40° C, 39% R.H.) for 29 ± 2 minutes. Subjects exercised at 60 ± 9% V[Combining Dot Above]O2peak, with methods for prescribing exercise retrospectively observed for each participant. Pearson product moment correlations were calculated for each prescriptive variable against the rate of change in Trec (° C·h), with stepwise multiple regressions performed on statistically significant variables (p ≤ 0.05). Linear regression identified the predicted intensity required to increase Trec by 1.0-2.0° C between 20- and 45-minute periods and the duration taken to increase Trec by 1.5° C in response to incremental intensities to guide prescription. Significant (p ≤ 0.05) relationships with the rate of change in Trec were observed for prescriptions based on relative power (W·kg; r = 0.764), power (%Powermax; r = 0.679), rating of perceived exertion (RPE) (r = 0.577), V[Combining Dot Above]O2 (%V[Combining Dot Above]O2peak; r = 0.562), heart rate (HR) (%HRmax; r = 0.534), and thermal sensation (r = 0.311). Stepwise multiple regressions observed relative power and RPE as variables to improve the model (r = 0.791), with no improvement after inclusion of any anthropometric variable. Prescription of exercise under heat stress using power (W·kg or %Powermax) has the strongest relationship with the rate of change in Trec with no additional requirement to correct for body composition within a normal range. Practitioners should therefore prescribe exercise intensity using relative power during isothermic HA training to increase Trec efficiently and maximize adaptation.

Responses of Plasma Atrial Natriuretic Peptide to High Intensity Submaximal Exercise in the Heat,

DTIC Science & Technology

1987-06-01

atrial natriuretic factor on blood pressure and renin - angiotensin - aldosterone system . Federation Proc 45: 2115-2121. Blain EH (1986) Atrial...acclimation adaptations. Conversely, plasma aldosterone (ALDO). renin activity (PRA) and cortisol (COR) all increased (p’O.05) pre-to post- exercise on each...Words: Atrial natriuretic peptide,-cortisol. plasma renin activity. aldosterone .- heat, males. Accession For -TIS ORA&I DTIC TAB 0 mnUnannounced 0

Exercise intensity modulates the appearance of circulating microvesicles with proangiogenic potential upon endothelial cells.

PubMed

Wilhelm, Eurico N; González-Alonso, José; Parris, Christopher; Rakobowchuk, Mark

2016-11-01

The effect of endurance exercise on circulating microvesicle dynamics and their impact on surrounding endothelial cells is unclear. Here we tested the hypothesis that exercise intensity modulates the time course of platelet (PMV) and endothelial-derived (EMV) microvesicle appearance in the circulation through hemodynamic and biochemical-related mechanisms, and that microvesicles formed during exercise would stimulate endothelial angiogenesis in vitro. Nine healthy young men had venous blood samples taken before, during, and throughout the recovery period after 1 h of moderate [46 ± 2% maximal oxygen uptake (V̇o 2max )] or heavy (67 ± 2% V̇o 2max ) intensity semirecumbent cycling and a time-matched resting control trial. In vitro experiments were performed by incubating endothelial cells with rest and exercise-derived microvesicles to examine their effects on cell angiogenic capacities. PMVs (CD41 + ) increased from baseline only during heavy exercise (from 21 ± 1 × 10 3 to 55 ± 8 × 10 3 and 48 ± 6 × 10 3 PMV/μl at 30 and 60 min, respectively; P < 0.05), returning to baseline early in postexercise recovery (P > 0.05), whereas EMVs (CD62E + ) were unchanged (P > 0.05). PMVs were related to brachial artery shear rate (r 2 = 0.43) and plasma norepinephrine concentrations (r 2 = 0.21) during exercise (P < 0.05). Exercise-derived microvesicles enhanced endothelial proliferation, migration, and tubule formation compared with rest microvesicles (P < 0.05). These results demonstrate substantial increases in circulating PMVs during heavy exercise and that exercise-derived microvesicles stimulate human endothelial cells by enhancing angiogenesis and proliferation. This involvement of microvesicles may be considered a novel mechanism through which exercise mediates vascular healing and adaptation. Copyright © 2016 the American Physiological Society.

Cardiac parasympathetic reactivation following exercise: implications for training prescription.

PubMed

Stanley, Jamie; Peake, Jonathan M; Buchheit, Martin

2013-12-01

The objective of exercise training is to initiate desirable physiological adaptations that ultimately enhance physical work capacity. Optimal training prescription requires an individualized approach, with an appropriate balance of training stimulus and recovery and optimal periodization. Recovery from exercise involves integrated physiological responses. The cardiovascular system plays a fundamental role in facilitating many of these responses, including thermoregulation and delivery/removal of nutrients and waste products. As a marker of cardiovascular recovery, cardiac parasympathetic reactivation following a training session is highly individualized. It appears to parallel the acute/intermediate recovery of the thermoregulatory and vascular systems, as described by the supercompensation theory. The physiological mechanisms underlying cardiac parasympathetic reactivation are not completely understood. However, changes in cardiac autonomic activity may provide a proxy measure of the changes in autonomic input into organs and (by default) the blood flow requirements to restore homeostasis. Metaboreflex stimulation (e.g. muscle and blood acidosis) is likely a key determinant of parasympathetic reactivation in the short term (0-90 min post-exercise), whereas baroreflex stimulation (e.g. exercise-induced changes in plasma volume) probably mediates parasympathetic reactivation in the intermediate term (1-48 h post-exercise). Cardiac parasympathetic reactivation does not appear to coincide with the recovery of all physiological systems (e.g. energy stores or the neuromuscular system). However, this may reflect the limited data currently available on parasympathetic reactivation following strength/resistance-based exercise of variable intensity. In this review, we quantitatively analyse post-exercise cardiac parasympathetic reactivation in athletes and healthy individuals following aerobic exercise, with respect to exercise intensity and duration, and fitness/training status. Our results demonstrate that the time required for complete cardiac autonomic recovery after a single aerobic-based training session is up to 24 h following low-intensity exercise, 24-48 h following threshold-intensity exercise and at least 48 h following high-intensity exercise. Based on limited data, exercise duration is unlikely to be the greatest determinant of cardiac parasympathetic reactivation. Cardiac autonomic recovery occurs more rapidly in individuals with greater aerobic fitness. Our data lend support to the concept that in conjunction with daily training logs, data on cardiac parasympathetic activity are useful for individualizing training programmes. In the final sections of this review, we provide recommendations for structuring training microcycles with reference to cardiac parasympathetic recovery kinetics. Ultimately, coaches should structure training programmes tailored to the unique recovery kinetics of each individual.

Impact of extreme exercise at high altitude on oxidative stress in humans.

PubMed

Quindry, John; Dumke, Charles; Slivka, Dustin; Ruby, Brent

2016-09-15

Exercise and oxidative stress research continues to grow as a physiological subdiscipline. The influence of high altitude on exercise and oxidative stress is among the recent topics of intense study in this area. Early findings indicate that exercise at high altitude has an independent influence on free radical generation and the resultant oxidative stress. This review provides a detailed summary of oxidative stress biochemistry as gleaned mainly from studies of humans exercising at high altitude. Understanding of the human response to exercise at altitude is largely derived from field-based research at altitudes above 3000 m in addition to laboratory studies which employ normobaric hypoxia. The implications of oxidative stress incurred during high altitude exercise appear to be a transient increase in oxidative damage followed by redox-sensitive adaptations in multiple tissues. These outcomes are consistent for lowland natives, high altitude acclimated sojourners and highland natives, although the latter group exhibits a more robust adaptive response. To date there is no evidence that altitude-induced oxidative stress is deleterious to normal training or recovery scenarios. Limited evidence suggests that deleterious outcomes related to oxidative stress are limited to instances where individuals are exposed to extreme elevations for extended durations. However, confirmation of this tentative conclusion requires further investigation. More applicably, altitude-induced hypoxia may have an independent influence on redox-sensitive adaptive responses to exercise and exercise recovery. If correct, these findings may hold important implications for athletes, mountaineers, and soldiers working at high altitude. These points are raised within the confines of published research on the topic of oxidative stress during exercise at altitude. © 2015 The Authors. The Journal of Physiology © 2015 The Physiological Society.

Impact of extreme exercise at high altitude on oxidative stress in humans

PubMed Central

Dumke, Charles; Slivka, Dustin; Ruby, Brent

2015-01-01

Abstract Exercise and oxidative stress research continues to grow as a physiological subdiscipline. The influence of high altitude on exercise and oxidative stress is among the recent topics of intense study in this area. Early findings indicate that exercise at high altitude has an independent influence on free radical generation and the resultant oxidative stress. This review provides a detailed summary of oxidative stress biochemistry as gleaned mainly from studies of humans exercising at high altitude. Understanding of the human response to exercise at altitude is largely derived from field‐based research at altitudes above 3000 m in addition to laboratory studies which employ normobaric hypoxia. The implications of oxidative stress incurred during high altitude exercise appear to be a transient increase in oxidative damage followed by redox‐sensitive adaptations in multiple tissues. These outcomes are consistent for lowland natives, high altitude acclimated sojourners and highland natives, although the latter group exhibits a more robust adaptive response. To date there is no evidence that altitude‐induced oxidative stress is deleterious to normal training or recovery scenarios. Limited evidence suggests that deleterious outcomes related to oxidative stress are limited to instances where individuals are exposed to extreme elevations for extended durations. However, confirmation of this tentative conclusion requires further investigation. More applicably, altitude‐induced hypoxia may have an independent influence on redox‐sensitive adaptive responses to exercise and exercise recovery. If correct, these findings may hold important implications for athletes, mountaineers, and soldiers working at high altitude. These points are raised within the confines of published research on the topic of oxidative stress during exercise at altitude. PMID:26453842

Classification of Physical Activity: Information to Artificial Pancreas Control Systems in Real Time.

PubMed

Turksoy, Kamuran; Paulino, Thiago Marques Luz; Zaharieva, Dessi P; Yavelberg, Loren; Jamnik, Veronica; Riddell, Michael C; Cinar, Ali

2015-10-06

Physical activity has a wide range of effects on glucose concentrations in type 1 diabetes (T1D) depending on the type (ie, aerobic, anaerobic, mixed) and duration of activity performed. This variability in glucose responses to physical activity makes the development of artificial pancreas (AP) systems challenging. Automatic detection of exercise type and intensity, and its classification as aerobic or anaerobic would provide valuable information to AP control algorithms. This can be achieved by using a multivariable AP approach where biometric variables are measured and reported to the AP at high frequency. We developed a classification system that identifies, in real time, the exercise intensity and its reliance on aerobic or anaerobic metabolism and tested this approach using clinical data collected from 5 persons with T1D and 3 individuals without T1D in a controlled laboratory setting using a variety of common types of physical activity. The classifier had an average sensitivity of 98.7% for physiological data collected over a range of exercise modalities and intensities in these subjects. The classifier will be added as a new module to the integrated multivariable adaptive AP system to enable the detection of aerobic and anaerobic exercise for enhancing the accuracy of insulin infusion strategies during and after exercise. © 2015 Diabetes Technology Society.

Classification of Physical Activity

PubMed Central

Turksoy, Kamuran; Paulino, Thiago Marques Luz; Zaharieva, Dessi P.; Yavelberg, Loren; Jamnik, Veronica; Riddell, Michael C.; Cinar, Ali

2015-01-01

Physical activity has a wide range of effects on glucose concentrations in type 1 diabetes (T1D) depending on the type (ie, aerobic, anaerobic, mixed) and duration of activity performed. This variability in glucose responses to physical activity makes the development of artificial pancreas (AP) systems challenging. Automatic detection of exercise type and intensity, and its classification as aerobic or anaerobic would provide valuable information to AP control algorithms. This can be achieved by using a multivariable AP approach where biometric variables are measured and reported to the AP at high frequency. We developed a classification system that identifies, in real time, the exercise intensity and its reliance on aerobic or anaerobic metabolism and tested this approach using clinical data collected from 5 persons with T1D and 3 individuals without T1D in a controlled laboratory setting using a variety of common types of physical activity. The classifier had an average sensitivity of 98.7% for physiological data collected over a range of exercise modalities and intensities in these subjects. The classifier will be added as a new module to the integrated multivariable adaptive AP system to enable the detection of aerobic and anaerobic exercise for enhancing the accuracy of insulin infusion strategies during and after exercise. PMID:26443291

Creatine supplementation with specific view to exercise/sports performance: an update

PubMed Central

2012-01-01

Creatine is one of the most popular and widely researched natural supplements. The majority of studies have focused on the effects of creatine monohydrate on performance and health; however, many other forms of creatine exist and are commercially available in the sports nutrition/supplement market. Regardless of the form, supplementation with creatine has regularly shown to increase strength, fat free mass, and muscle morphology with concurrent heavy resistance training more than resistance training alone. Creatine may be of benefit in other modes of exercise such as high-intensity sprints or endurance training. However, it appears that the effects of creatine diminish as the length of time spent exercising increases. Even though not all individuals respond similarly to creatine supplementation, it is generally accepted that its supplementation increases creatine storage and promotes a faster regeneration of adenosine triphosphate between high intensity exercises. These improved outcomes will increase performance and promote greater training adaptations. More recent research suggests that creatine supplementation in amounts of 0.1 g/kg of body weight combined with resistance training improves training adaptations at a cellular and sub-cellular level. Finally, although presently ingesting creatine as an oral supplement is considered safe and ethical, the perception of safety cannot be guaranteed, especially when administered for long period of time to different populations (athletes, sedentary, patient, active, young or elderly). PMID:22817979

Acute and Chronic Exercise in Animal Models.

PubMed

Thu, Vu Thi; Kim, Hyoung Kyu; Han, Jin

2017-01-01

Numerous animal cardiac exercise models using animal subjects have been established to uncover the cardiovascular physiological mechanism of exercise or to determine the effects of exercise on cardiovascular health and disease. In most cases, animal-based cardiovascular exercise modalities include treadmill running, swimming, and voluntary wheel running with a series of intensities, times, and durations. Those used animals include small rodents (e.g., mice and rats) and large animals (e.g., rabbits, dogs, goats, sheep, pigs, and horses). Depending on the research goal, each experimental protocol should also describe whether its respective exercise treatment can produce the anticipated acute or chronic cardiovascular adaptive response. In this chapter, we will briefly describe the most common kinds of animal models of acute and chronic cardiovascular exercises that are currently being conducted and are likely to be chosen in the near future. Strengths and weakness of animal-based cardiac exercise modalities are also discussed.

Intensive Exercise Training During Bed Rest Attenuates Deconditioning

NASA Technical Reports Server (NTRS)

Greenleaf, John E.

1997-01-01

Intensive exercise training during bed rest attenuates deconditioning. Med. Sci. Sports Exerc., Vol. 29, No. 2, pp. 207-215, 1997. A 30-d 6 deg head-down bed rest project was conducted to evaluate variable high-intensity, short-duration, isotonic cycle ergometer exercise (ITE) training and high-intensity intermittent resistive isokinetic exercise (IKE) training regimens designed to maintain peak VO2 and muscle mass, strength, and endurance at ambulatory control levels throughout prolonged bed rest. Other elements of the deconditioning (adaptive) syndrome, such as proprioception, psychological performance, hypovolemia, water balance, body composition, and orthostatic tolerance, were also measured. Major findings are summarized in this paper. Compared with response during bed rest of the no exercise (NOE) control group: the ITE training regimen (a) maintained work capacity (peak VO2), (b) maintained plasma and red cell volumes, (c) induced positive body water balance, (d) decreased quality of sleep and mental concentration, and (e) had no effect on the decrease in orthostatic tolerance; the IKE training regimen (f) attenuated the decrease in peak VO2 by 50%, (g) attenuated loss of red cell volume by 40% but had no effect on loss of plasma volume, (b) induced positive body water balance, (i) had no adverse effect on quality of sleep or concentration, and 0) had no effect on the decrease in orthostatic tolerance. These findings suggest that various elements of the deconditioning syndrome can be manipulated by duration and intensity of ITE or IKE training regimens and that several different training protocols will be required to maintain or restore physiological and psychological performance of individuals confined to prolonged bed rest.

Oxygen Consumption and Usage During Physical Exercise: The Balance Between Oxidative Stress and ROS-Dependent Adaptive Signaling

PubMed Central

Zhao, Zhongfu; Koltai, Erika; Ohno, Hideki; Atalay, Mustafa

2013-01-01

Abstract The complexity of human DNA has been affected by aerobic metabolism, including endurance exercise and oxygen toxicity. Aerobic endurance exercise could play an important role in the evolution of Homo sapiens, and oxygen was not important just for survival, but it was crucial to redox-mediated adaptation. The metabolic challenge during physical exercise results in an elevated generation of reactive oxygen species (ROS) that are important modulators of muscle contraction, antioxidant protection, and oxidative damage repair, which at moderate levels generate physiological responses. Several factors of mitochondrial biogenesis, such as peroxisome proliferator-activated receptor-γ coactivator 1α (PGC-1α), mitogen-activated protein kinase, and SIRT1, are modulated by exercise-associated changes in the redox milieu. PGC-1α activation could result in decreased oxidative challenge, either by upregulation of antioxidant enzymes and/or by an increased number of mitochondria that allows lower levels of respiratory activity for the same degree of ATP generation. Endogenous thiol antioxidants glutathione and thioredoxin are modulated with high oxygen consumption and ROS generation during physical exercise, controlling cellular function through redox-sensitive signaling and protein–protein interactions. Endurance exercise-related angiogenesis, up to a significant degree, is regulated by ROS-mediated activation of hypoxia-inducible factor 1α. Moreover, the exercise-associated ROS production could be important to DNA methylation and post-translation modifications of histone residues, which create heritable adaptive conditions based on epigenetic features of chromosomes. Accumulating data indicate that exercise with moderate intensity has systemic and complex health-promoting effects, which undoubtedly involve regulation of redox homeostasis and signaling. Antioxid. Redox Signal. 18, 1208–1246. PMID:22978553

The induction and decay of heat acclimatisation in trained athletes.

PubMed

Armstrong, L E; Maresh, C M

1991-11-01

Heat acclimatisation/acclimation involves a complex of adaptations which includes decreased heart rate, rectal temperature, perceived exertion as well as increased plasma volume and sweat rate. These adaptations serve to reduce physiological strain, improve an athlete's ability to exercise in a hot environment, and reduce the incidence of some forms of heat illness. Few differences exist in the ability of men and women to acclimatise to heat. Typically, older runners do not perform in the heat as well as younger runners, but physical training can negate differences between these groups. Hormonal adaptations (e.g. aldosterone, vasopressin) during heat acclimatisation encourage fluid-electrolyte retention and cardiovascular stability. Athletes with high maximal aerobic power (VO2max) acclimatise to heat faster (and lose adaptations slower when they are inactive in a cool environment) than athletes with low VO2max values. Physical training in a cool environment improves physiological responses to exercise at high ambient temperatures. In attempting to optimise heat acclimatisation, athletes should maintain fluid-electrolyte balance, exercise at intensities greater than 50% VO2max for 10 to 14 days, and avoid factors (e.g. sleep loss, infectious disease) which are known to reduce heat tolerance. Once acclimatisation has been achieved, inactivity results in a decay of favourable adaptations, after only a few days or weeks.

Prevalence and predictors of unsupervised walking and physical activity in a community population of women with fibromyalgia.

PubMed

López-Roig, Sofía; Pastor, María-Ángeles; Peñacoba, Cecilia; Lledó, Ana; Sanz, Yolanda; Velasco, Lilian

2016-08-01

Physical exercise is recognized as a component of the evidence-based guidelines for treatment of fibromyalgia. Walking is a low-moderate intensity exercise easily adaptable to a fibromyalgia patient's situation. The present study aims to estimate the prevalence of unsupervised walking for exercise in women with fibromyalgia, to describe their level of physical activity and to identify their predictors among socio-demographic, symptom perception and medical advice to walk. A cross-sectional survey with 920 women (all members of fibromyalgia associations) completed the International Physical Activity Questionnaire-Short Form and self-reported scales to assess symptom perception, walking, medical advice to walk and physical comorbidity. The prevalence of reported walking regularly as physical exercise was 30.8 % and it was predicted by medical advice (odds ratio, OR 1.876), age (OR 1.021) and fatigue intensity (OR 0.912). The prevalence of physical activity was 16 % for high-intensity activity, 40 % for moderate activity and 44 % for low activity. Predictors of low versus moderate and high physical activity were pain intensity (OR 1.171) and fatigue impact perception (OR 1.076). Evidence shows a low percentage of women with fibromyalgia walking regularly for physical exercise. Most reported low or moderate physical activity. The results indicate the importance of doctors' advice in promoting walking. Symptom perception and socio-demographic characteristics were weak predictors. Further work is required to examine other determinants of these low levels.

Systematic strength training as a model of therapeutic intervention. A controlled trial in postmenopausal women with osteopenia.

PubMed

Hartard, M; Haber, P; Ilieva, D; Preisinger, E; Seidl, G; Huber, J

1996-01-01

Physical exercise is often recommended as a therapeutic tool to combat pre- and postmenopausal loss of bone density. However, the relationship between training dosage (intensity, duration, frequency) and the effect on bone density still is undergoing discussion. Furthermore, the exercise quantification programs are often described so inadequately that they are neither quantitatively nor qualitatively reproducible. The aim of this investigation was to determine whether a clearly defined training of muscle strength, under defined safety aspects, performed only twice weekly, can counteract bone density loss in women with postmenopausal osteopenia. Data from 16 women in the training group (age, 63.6 +/- 6.2 yr) and 15 women in the control group (age, 67.4 +/-9.7 yr), of comparable height and weight, were evaluated. Strength training was performed for 6 mo as continually adapted strength training, providing an intensity of about 70% of each test person's one repetition maximum. Bone mineral density of lumbar vertebrae 2 to 4 and the femoral neck was measured by dual-energy x-ray absorptiometry. Maximum performance in watts and parameters of hemodynamics were controlled with a bicycle ergometer test to maximal effort. In addition, metabolic data were assessed. In the lumbar spine and femoral neck, the training group showed no significant changes, whereas the control group demonstrated a significant loss of bone mineral density, especially in the femoral neck (P<0.05). The strength increase was highly significant in all exercised muscle groups, rising to about 70% above the pretraining status (P<0.001). Heart rate and blood pressure data indicated a slight economization, metabolism was not significantly influenced. Based on these findings, we conclude that continually adapted strength training is an effective, safe, reproducible, and adaptable method of therapeutic strength training, following only two exercise sessions per week.

Integrated physiological mechanisms of exercise performance, adaptation, and maladaptation to heat stress.

PubMed

Sawka, Michael N; Leon, Lisa R; Montain, Scott J; Sonna, Larry A

2011-10-01

This article emphasizes significant recent advances regarding heat stress and its impact on exercise performance, adaptations, fluid electrolyte imbalances, and pathophysiology. During exercise-heat stress, the physiological burden of supporting high skin blood flow and high sweating rates can impose considerable cardiovascular strain and initiate a cascade of pathophysiological events leading to heat stroke. We examine the association between heat stress, particularly high skin temperature, on diminishing cardiovascular/aerobic reserves as well as increasing relative intensity and perceptual cues that degrade aerobic exercise performance. We discuss novel systemic (heat acclimation) and cellular (acquired thermal tolerance) adaptations that improve performance in hot and temperate environments and protect organs from heat stroke as well as other dissimilar stresses. We delineate how heat stroke evolves from gut underperfusion/ischemia causing endotoxin release or the release of mitochondrial DNA fragments in response to cell necrosis, to mediate a systemic inflammatory syndrome inducing coagulopathies, immune dysfunction, cytokine modulation, and multiorgan damage and failure. We discuss how an inflammatory response that induces simultaneous fever and/or prior exposure to a pathogen (e.g., viral infection) that deactivates molecular protective mechanisms interacts synergistically with the hyperthermia of exercise to perhaps explain heat stroke cases reported in low-risk populations performing routine activities. Importantly, we question the "traditional" notion that high core temperature is the critical mediator of exercise performance degradation and heat stroke. Published 2011. This article is a U.S. Government work and is in the public domain in the USA.

Changes in the heart rate recovery to endurance effort after high intensity interval, strength, and concurrent exercise training in patients with insulin resistance.

PubMed

Álvarez, Cristian; Ramírez-Campillo, Rodrigo; Martínez, Cristian; Castro-Sepúlveda, Mauricio; Cano-Montoya, Johnathan; Mancilla, Rodrigo; Flores-Opazo, Marcelo

2017-11-01

The aim of this study was to assess the effects of three exercise training programs in the adaptation of the heart rate recovery of patients with insulin resistance. We studied 43 women with insulin resistance, which were assigned to three training groups: 1) high intensity interval training (HIT, age 39.0±10 years); 2) strength training (ST, age 33.9±9.4 years); 3) HIT+ST (MIXT, age 43.3±8.1 years); and 4) control group (CG, age 40.1±11 years). Heart rate was measured at rest (HRrest), during the 2-km-walking-test (UKKT) for mean (HRDE), and maximum (HRMDE) values, and during the recovery at one, two, and three minutes after the UKKT. Additionally, anthropometric measurements (body mass and body mass index) were assessed. HIT significantly decreased HRrest and HRDE (-4.5% and -2% respectively, P<0.05). MIXT training also decreased HRDE in -3% whilst both average and maximal HR during UKK were significantly increased in the control group HRDE (+2% and +3% respectively). Moreover, there were significant reductions in HR recovery at 1, 2 and 3 minutes after both HIT and MIXT training, whereas these values were increased in control group. Our findings suggest that HIT induces meaningful cardiovascular adaptations in patient with insulin resistance, reducing heart rate at rest, as well as during and after exercise, and that complementary strength training increases these adaptations.

Does Resistance Training Stimulate Cardiac Muscle Hypertrophy?

ERIC Educational Resources Information Center

Bloomer, Richard J.

2003-01-01

Reviews the literature on the left ventricular structural adaptations induced by resistance/strength exercise, focusing on human work, particularly well-trained strength athletes engaged in regular, moderate- to high-intensity resistance training (RT). The article discusses both genders and examines the use of anabolic-androgenic steroids in…

Intermittent and continuous high-intensity exercise training induce similar acute but different chronic muscle adaptations.

PubMed

Cochran, Andrew J R; Percival, Michael E; Tricarico, Steven; Little, Jonathan P; Cermak, Naomi; Gillen, Jenna B; Tarnopolsky, Mark A; Gibala, Martin J

2014-05-01

High-intensity interval training (HIIT) performed in an 'all-out' manner (e.g. repeated Wingate tests) is a time-efficient strategy to induce skeletal muscle remodelling towards a more oxidative phenotype. A fundamental question that remains unclear, however, is whether the intermittent or 'pulsed' nature of the stimulus is critical to the adaptive response. In study 1, we examined whether the activation of signalling cascades linked to mitochondrial biogenesis was dependent on the manner in which an acute high-intensity exercise stimulus was applied. Subjects performed either four 30 s Wingate tests interspersed with 4 min of rest (INT) or a bout of continuous exercise (CONT) that was matched for total work (67 ± 7 kJ) and which required ∼4 min to complete as fast as possible. Both protocols elicited similar increases in markers of adenosine monophosphate-activated protein kinase (AMPK) and p38 mitogen-activated protein kinase activation, as well as Peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) mRNA expression (main effects for time, P ≤ 0.05). In study 2, we determined whether 6 weeks of the CONT protocol (3 days per week) would increase skeletal muscle mitochondrial content to a similar extent to what we have previously reported after 6 weeks of INT. Despite similar acute signalling responses to the CONT and INT protocols, training with CONT did not increase the maximal activity or protein content of a range of mitochondrial markers. However, peak oxygen uptake was higher after CONT training (from 45.7 ± 5.4 to 48.3 ± 6.5 ml kg(-1) min(-1); P < 0.05) and 250 kJ time trial performance was improved (from 26:32 ± 4:48 to 23:55 ± 4:16 min:s; P < 0.001) in our recreationally active participants. We conclude that the intermittent nature of the stimulus is important for maximizing skeletal muscle adaptations to low-volume, all-out HIIT. Despite the lack of skeletal muscle mitochondrial adaptations, our data show that a training programme based on a brief bout of high-intensity exercise, which lasted <10 min per session including warm-up, and performed three times per week for 6 weeks, improved peak oxygen uptake in young healthy subjects. © 2014 The Authors. Experimental Physiology © 2014 The Physiological Society.

Hypoxia and training-induced adaptation of hormonal responses to exercise in humans.

PubMed

Engfred, K; Kjaer, M; Secher, N H; Friedman, D B; Hanel, B; Nielsen, O J; Bach, F W; Galbo, H; Levine, B D

1994-01-01

To establish whether or not hypoxia influences the training-induced adaptation of hormonal responses to exercise, 21 healthy, untrained subjects (2) years, mean (SE)] were studied in three groups before and after 5 weeks' training (cycle ergometer, 45 min.day-1, 5 days.week-1). Group 1 trained at sea level at 70% maximal oxygen uptake (VO2max), group 2 in a hypobaric chamber at a simulated altitude of 2500 m at 70% of altitude VO2max, and group 3 at a simulated altitude of 2500 m at the same absolute work rate as group 1. Arterial blood was sampled before, during and at the end of exhaustive cycling at sea level (85% of pretraining VO2max). VO2max increased by 12 (2)% with no significant difference between groups, whereas endurance improved most in group 1 (P < 0.05). Training-induced changes in response to exercise of noradrenaline, adrenaline, growth hormone, beta-endorphin, glucagon, and insulin were similar in the three groups. Concentrations of erythropoietin and 2,3-diphosphoglycerate at rest did not change over the training period. In conclusion, within 5 weeks of training, no further adaptation of hormonal exercise responses takes place if intensity is increased above 70% VO2max. Furthermore, hypoxia per se does not add to the training-induced hormonal responses to exercise.

Is there really an eccentric action of the hamstrings during the swing phase of high-speed running? Part II: Implications for exercise.

PubMed

Van Hooren, Bas; Bosch, Frans

2017-12-01

We have previously argued that there may actually be no significant eccentric, but rather predominantly an isometric action of the hamstring muscle fibres during the swing phase of high-speed running when the attachment points of the hamstrings are moving apart. Based on this we suggested that isometric rather than eccentric exercises are a more specific way of conditioning the hamstrings for high-speed running. In this review we argue that some of the presumed beneficial adaptations following eccentric training may actually not be related to the eccentric muscle fibre action, but to other factors such as exercise intensity. Furthermore, we discuss several disadvantages associated with commonly used eccentric hamstring exercises. Subsequently, we argue that high-intensity isometric exercises in which the series elastic element stretches and recoils may be equally or even more effective at conditioning the hamstrings for high-speed running, since they also avoid some of the negative side effects associated with eccentric training. We provide several criteria that exercises should fulfil to effectively condition the hamstrings for high-speed running. Adherence to these criteria will guarantee specificity with regards to hamstrings functioning during running. Practical examples of isometric exercises that likely meet several criteria are provided.

Prescribing exercise for prevention and treatment of gestational diabetes: review of suggested recommendations.

PubMed

Bianchi, Cristina; Battini, Lorella; Aragona, Michele; Lencioni, Cristina; Ottanelli, Serena; Romano, Matilde; Calabrese, Maria; Cuccuru, Ilaria; De Bellis, Alessandra; Mori, Mary Liana; Leopardi, Anna; Sabbatini, Gigliola; Bottone, Pietro; Miccoli, Roberto; Trojano, Giuseppe; Salerno, Maria Giovanna; Del Prato, Stefano; Bertolotto, Alessandra

2017-04-01

Exercise has been proved to be safe during pregnancy and to offer benefits for both mother and fetus; moreover, physical activity may represent a useful tool for gestational diabetes prevention and treatment. Therefore, all women in uncomplicated pregnancy should be encouraged to engage in physical activity as part of a healthy lifestyle. However, exercise in pregnancy needs a careful medical evaluation to exclude medical or obstetric contraindications to exercise, and an appropriate prescription considering frequency, intensity, type and duration of exercise, to carefully balance between potential benefits and potential harmful effects. Moreover, some precautions related to anatomical and functional adaptations observed during pregnancy should be taken into consideration. This review summarized the suggested recommendations for physical activity among pregnant women with focus on gestational diabetes.

Superior mitochondrial adaptations in human skeletal muscle after interval compared to continuous single‐leg cycling matched for total work

PubMed Central

MacInnis, Martin J.; Zacharewicz, Evelyn; Martin, Brian J.; Haikalis, Maria E.; Skelly, Lauren E.; Tarnopolsky, Mark A.; Murphy, Robyn M.

2016-01-01

Key points A classic unresolved issue in human integrative physiology involves the role of exercise intensity, duration and volume in regulating skeletal muscle adaptations to training.We employed counterweighted single‐leg cycling as a unique within‐subject model to investigate the role of exercise intensity in promoting training‐induced increases in skeletal muscle mitochondrial content.Six sessions of high‐intensity interval training performed over 2 weeks elicited greater increases in citrate synthase maximal activity and mitochondrial respiration compared to moderate‐intensity continuous training matched for total work and session duration.These data suggest that exercise intensity, and/or the pattern of contraction, is an important determinant of exercise‐induced skeletal muscle remodelling in humans. Abstract We employed counterweighted single‐leg cycling as a unique model to investigate the role of exercise intensity in human skeletal muscle remodelling. Ten young active men performed unilateral graded‐exercise tests to measure single‐leg V˙O2, peak and peak power (W peak). Each leg was randomly assigned to complete six sessions of high‐intensity interval training (HIIT) [4 × (5 min at 65% W peak and 2.5 min at 20% W peak)] or moderate‐intensity continuous training (MICT) (30 min at 50% W peak), which were performed 10 min apart on each day, in an alternating order. The work performed per session was matched for MICT (143 ± 8.4 kJ) and HIIT (144 ± 8.5 kJ, P > 0.05). Post‐training, citrate synthase (CS) maximal activity (10.2 ± 0.8 vs. 8.4 ± 0.9 mmol kg protein−1 min−1) and mass‐specific [pmol O2•(s•mg wet weight)−1] oxidative phosphorylation capacities (complex I: 23.4 ± 3.2 vs. 17.1 ± 2.8; complexes I and II: 58.2 ± 7.5 vs. 42.2 ± 5.3) were greater in HIIT relative to MICT (interaction effects, P < 0.05); however, mitochondrial function [i.e. pmol O2•(s•CS maximal activity)−1] measured under various conditions was unaffected by training (P > 0.05). In whole muscle, the protein content of COXIV (24%), NDUFA9 (11%) and mitofusin 2 (MFN2) (16%) increased similarly across groups (training effects, P < 0.05). Cytochrome c oxidase subunit IV (COXIV) and NADH:ubiquinone oxidoreductase subunit A9 (NDUFA9) were more abundant in type I than type II fibres (P < 0.05) but training did not increase the content of COXIV, NDUFA9 or MFN2 in either fibre type (P > 0.05). Single‐leg V˙O2, peak was also unaffected by training (P > 0.05). In summary, single‐leg cycling performed in an interval compared to a continuous manner elicited superior mitochondrial adaptations in human skeletal muscle despite equal total work. PMID:27396440

Thermoregulatory adaptations associated with training and heat acclimation.

PubMed

Geor, R J; McCutcheon, L J

1998-04-01

The large metabolic heat load generated as a consequence of muscular work requires activation of thermoregulatory mechanisms in order to prevent an excessive and potentially dangerous rise in body temperature during exercise. Although the horse has highly efficient heat dissipatory mechanisms, there are a number of circumstances in which the thermoregulatory system may be overwhelmed, resulting in the development of critical hyperthermia. The risk for development of life-threatening hyperthermia is greatest when (1) the horse is inadequately conditioned for the required level of physical performance; (2) exercise is undertaken in hot and particularly, in hot and humid ambient conditions; and (3) there is an impairment to thermoregulatory mechanisms (e.g., severe dehydration, anhidrosis). Both exercise training under cool to moderate ambient conditions and a period of repeated exposure to, and exercise in, hot ambient conditions (heat acclimation) will result in a number of physiologic adaptations conferring improved thermoregulatory ability. These adaptations include an expanded plasma volume, greater stability of cardiovascular function during exercise, and an improved efficiency of evaporative heat loss as a result of alterations in the sweating response. Collectively, these adjustments serve to attenuate the rise in core body temperature in response to a given intensity of exercise. The magnitude of the physiologic adaptations occurring during exercise training and heat acclimation is a reflection of the thermal load imposed on the horse. Therefore, when compared with a period of training in cool conditions, the larger thermal stimulus associated with repeated exercise in hot ambient conditions will invoke proportionally greater thermoregulatory adaptations. Although it is not possible to eliminate the effects of adverse environmental conditions on exercise performance, it is clear that a thorough exercise training program together with a subsequent period of acclimatization will serve to ameliorate the impact of the environment. Based on our current understanding of the nature and extent of thermoregulatory adaptations in the horse, the following conclusions can be made: 1. A 2- to 3-month period of exercise training geared toward the specific athletic endeavor to be undertaken will result in substantial improvements in thermoregulatory capacity and is an absolute requirement for horses required to compete in hot ambient conditions. 2. Although physical training in a cool environment improves physiologic responses to exercise at high ambient temperatures, a 2-week period of moderate exercise training in these more adverse conditions is necessary for optimization of thermoregulatory function and physical performance. 3. Heat acclimation does not reduce the need for close monitoring of horses during training and competition in the heat. This is particularly true in hot, humid ambient conditions, where the biophysical limitations to sweat evaporation can result in development of severe hyperthermia, regardless of the state of training or heat acclimation.

[Endurance training and cardial adaptation (athlete's heart)].

PubMed

Dickhuth, Hans-Hermann; Röcker, Kai; Mayer, Frank; König, Daniel; Korsten-Reck, Ulrike

2004-06-01

One essential function of the cardiovascular system is to provide an adequate blood supply to all organs, including the skeletal muscles at rest and during exercise. Adaptation to chronic exercise proceeds mainly via the autonomic nervous system. On the one hand, peripheral muscles influence the autonomic reactions through "feedback" control via ergoreceptors, in particular, mechano- and chemoreceptors. On the other hand, there is central control in the sense of a "feed forward" regulation, e. g., the reaction of an athlete before competition. Along with other influential factors, such as circulatory presso-, chemo-, and volume receptors, the incoming impulses are processed in vegetative centers.A cardiovascular reaction, then, is the result of nerval and humoral sympathetic and parasympathetic activity. At rest, the parasympathetic tone dominates. It reduces heart frequency and conduction velocity. The high vagal tone is initially reduced with increasing physical exertion and switches at higher intensity to increasingly sympathetic activation. This mechanism of reaction to exercise is supported by inverse central and peripheral transmissions.Chronic endurance training leads to an improved local aerobic capacity of the exercised musculature. At rest, it augments parasympathetic activity when the muscle mass is sufficiently large, i. e., 20-30% of the skeletal musculature. The extent of the adaptation depends on individual factors, such as scope, intensity of training, and type of muscle fiber. A higher vagal tone delays the increase in the sympathetic tone during physical exertion. The regulatory range of heart rate, contractility, diastolic function, and blood pressure is increased. In addition, adaptation results in functional and structural changes in the vascular system. Cardiocirculatory work is economized, and maximum performance and oxygen uptake are improved. Endurance training exceeding an individual limit causes harmonic enlargement and hypertrophy of the heart. The thickness of both, the septum and posterior wall increases to the same extent as the interior volume. The mass/volume ratio, and therefore the maximum systolic wall stress, remains constant in contrast to pathologic forms of hypertrophy. Adaptations, including function and size of the heart, show a regression in healthy inactive persons without any structural heart disease.

Severity of structural and functional right ventricular remodeling depends on training load in an experimental model of endurance exercise.

PubMed

Sanz-de la Garza, Maria; Rubies, Cira; Batlle, Montserrat; Bijnens, Bart H; Mont, Lluis; Sitges, Marta; Guasch, Eduard

2017-09-01

Arrhythmogenic right ventricular (RV) remodeling has been reported in response to regular training, but it remains unclear how exercise intensity affects the presence and extent of such remodeling. We aimed to assess the relationship between RV remodeling and exercise load in a long-term endurance training model. Wistar rats were conditioned to run at moderate (MOD; 45 min, 30 cm/s) or intense (INT; 60 min, 60 cm/s) workloads for 16 wk; sedentary rats served as controls. Cardiac remodeling was assessed with standard echocardiographic and tissue Doppler techniques, sensor-tip pressure catheters, and pressure-volume loop analyses. After MOD training, both ventricles similarly dilated (~16%); the RV apical segment deformation, but not the basal segment deformation, was increased [apical strain rate (SR): -2.9 ± 0.5 vs. -3.3 ± 0.6 s -1 , SED vs. MOD]. INT training prompted marked RV dilatation (~26%) but did not further dilate the left ventricle (LV). A reduction in both RV segments' deformation in INT rats (apical SR: -3.3 ± 0.6 vs. -3.0 ± 0.4 s -1 and basal SR: -3.3 ± 0.7 vs. -2.7 ± 0.6 s -1 , MOD vs. INT) led to decreased global contractile function (maximal rate of rise of LV pressure: 2.53 ± 0.15 vs. 2.17 ± 0.116 mmHg/ms, MOD vs. INT). Echocardiography and hemodynamics consistently pointed to impaired RV diastolic function in INT rats. LV systolic and diastolic functions remained unchanged in all groups. In conclusion, we showed a biphasic, unbalanced RV remodeling response with increasing doses of exercise: physiological adaptation after MOD training turns adverse with INT training, involving disproportionate RV dilatation, decreased contractility, and impaired diastolic function. Our findings support the existence of an exercise load threshold beyond which cardiac remodeling becomes maladaptive. NEW & NOTEWORTHY Exercise promotes left ventricular eccentric hypertrophy with no changes in systolic or diastolic function in healthy rats. Conversely, right ventricular adaptation to physical activity follows a biphasic, dose-dependent, and segmentary pattern. Moderate exercise promotes a mild systolic function enhancement at the right ventricular apex and more intense exercise impairs systolic and diastolic function. Copyright © 2017 the American Physiological Society.

Adaptive motion artifact reducing algorithm for wrist photoplethysmography application

NASA Astrophysics Data System (ADS)

Zhao, Jingwei; Wang, Guijin; Shi, Chenbo

2016-04-01

Photoplethysmography (PPG) technology is widely used in wearable heart pulse rate monitoring. It might reveal the potential risks of heart condition and cardiopulmonary function by detecting the cardiac rhythms in physical exercise. However the quality of wrist photoelectric signal is very sensitive to motion artifact since the thicker tissues and the fewer amount of capillaries. Therefore, motion artifact is the major factor that impede the heart rate measurement in the high intensity exercising. One accelerometer and three channels of light with different wavelengths are used in this research to analyze the coupled form of motion artifact. A novel approach is proposed to separate the pulse signal from motion artifact by exploiting their mixing ratio in different optical paths. There are four major steps of our method: preprocessing, motion artifact estimation, adaptive filtering and heart rate calculation. Five healthy young men are participated in the experiment. The speeder in the treadmill is configured as 12km/h, and all subjects would run for 3-10 minutes by swinging the arms naturally. The final result is compared with chest strap. The average of mean square error (MSE) is less than 3 beats per minute (BPM/min). Proposed method performed well in intense physical exercise and shows the great robustness to individuals with different running style and posture.

Short-term intense exercise training reduces stress markers and alters the transcriptional response to exercise in skeletal muscle.

PubMed

Hinkley, J Matthew; Konopka, Adam R; Suer, Miranda K; Harber, Matthew P

2017-03-01

The purpose of this investigation was to examine the influence of short-term intense endurance training on cycling performance, along with the acute and chronic signaling responses of skeletal muscle stress and stability markers. Ten recreationally active subjects (25 ± 2 yr, 79 ± 3 kg, 47 ± 2 ml·kg -1 ·min -1 ) were studied before and after a 12-day cycling protocol to examine the effects of short-term intense (70-100% V̇o 2max ) exercise training on resting and exercise-induced regulation of molecular factors related to skeletal muscle cellular stress and protein stability. Skeletal muscle biopsies were taken at rest and 3 h following a 20-km cycle time trial on days 1 and 12 to measure mRNA expression and protein content. Training improved ( P < 0.05) cycling performance by 5 ± 1%. Protein oxidation was unaltered on day 12 , while resting SAPK/JNK phosphorylation was reduced ( P < 0.05), suggesting a reduction in cellular stress. The maintenance in the myocellular environment may be due to synthesis of cytoprotective markers, along with enhanced degradation of damage proteins, as training tended ( P < 0.10) to increase resting protein content of manganese superoxide dismutase and heat shock protein 70 (HSP70), while mRNA expression of MuRF-1 was elevated ( P < 0.05). Following training ( day 12 ), the acute exercise-induced transcriptional response of TNF-α, NF-κB, MuRF-1, and PGC1α was attenuated ( P < 0.05) compared with day 1 Collectively, these data suggest that short-term intense training enhances protein stability, creating a cellular environment capable of resistance to exercise-induced stress, which may be favorable for adaptation. Copyright © 2017 the American Physiological Society.

Short-term intense exercise training reduces stress markers and alters the transcriptional response to exercise in skeletal muscle

PubMed Central

Konopka, Adam R.; Suer, Miranda K.

2017-01-01

The purpose of this investigation was to examine the influence of short-term intense endurance training on cycling performance, along with the acute and chronic signaling responses of skeletal muscle stress and stability markers. Ten recreationally active subjects (25 ± 2 yr, 79 ± 3 kg, 47 ± 2 ml·kg−1·min−1) were studied before and after a 12-day cycling protocol to examine the effects of short-term intense (70–100% V̇o2max) exercise training on resting and exercise-induced regulation of molecular factors related to skeletal muscle cellular stress and protein stability. Skeletal muscle biopsies were taken at rest and 3 h following a 20-km cycle time trial on days 1 and 12 to measure mRNA expression and protein content. Training improved (P < 0.05) cycling performance by 5 ± 1%. Protein oxidation was unaltered on day 12, while resting SAPK/JNK phosphorylation was reduced (P < 0.05), suggesting a reduction in cellular stress. The maintenance in the myocellular environment may be due to synthesis of cytoprotective markers, along with enhanced degradation of damage proteins, as training tended (P < 0.10) to increase resting protein content of manganese superoxide dismutase and heat shock protein 70 (HSP70), while mRNA expression of MuRF-1 was elevated (P < 0.05). Following training (day 12), the acute exercise-induced transcriptional response of TNF-α, NF-κB, MuRF-1, and PGC1α was attenuated (P < 0.05) compared with day 1. Collectively, these data suggest that short-term intense training enhances protein stability, creating a cellular environment capable of resistance to exercise-induced stress, which may be favorable for adaptation. PMID:28039193

Maternal Cardiac Adaptations to a Physical Exercise Program during Pregnancy.

PubMed

Perales, María; Santos-Lozano, Alejandro; Sanchis-Gomar, Fabian; Luaces, María; Pareja-Galeano, Helios; Garatachea, Nuria; Barakat, Rubén; Lucia, Alejandro

2016-05-01

Scarce evidence exists regarding the effects of regular pregnancy exercise on maternal cardiovascular health. We aimed to study, using a randomized controlled trial design, the effects of pregnancy exercise on echocardiographic indicators of hemodynamics, cardiac remodeling, left ventricular (LV) function, and cardiovascular disease (CVD) risk factors. Two hundred forty-one healthy pregnant women were assigned to a control (standard care) or intervention (exercise) group (initial n = 121/120). The intervention (weeks 9-11 to 38-39) included three supervised sessions per week (55-60 min, with light-moderate intensity aerobic and strength exercises). The main findings were as follows: (i) the proportion of women with excessive weight gain at end pregnancy was lower in the exercise group compared with controls (18% vs 40%, P = 0.005), and (ii) there was a tendency toward lower prevalence of depression at end pregnancy in the former (P = 0.029, threshold P value set at 0.013). No significant exercise training effect was essentially found for echocardiographic variables, CVD risk factors, type/duration of labor, or newborn's outcomes (weight, height, head circumference, Apgar scores, and umbilical cord pH). Light-moderate intensity supervised exercise is safe for healthy pregnant women and does not impose an additional cardiac overload beyond gestation or affect the main pregnancy outcomes. Such intervention might help decrease, at least partly, the risk of two CVD-associated conditions, excessive weight gain and depression.

Cycle training modulates satellite cell and transcriptional responses to a bout of resistance exercise.

PubMed

Murach, Kevin A; Walton, R Grace; Fry, Christopher S; Michaelis, Sami L; Groshong, Jason S; Finlin, Brian S; Kern, Philip A; Peterson, Charlotte A

2016-09-01

This investigation evaluated whether moderate-intensity cycle ergometer training affects satellite cell and molecular responses to acute maximal concentric/eccentric resistance exercise in middle-aged women. Baseline and 72 h postresistance exercise vastus lateralis biopsies were obtained from seven healthy middle-aged women (56 ± 5 years, BMI 26 ± 1, VO2max 27 ± 4) before and after 12 weeks of cycle training. Myosin heavy chain (MyHC) I- and II-associated satellite cell density and cross-sectional area was determined via immunohistochemistry. Expression of 93 genes representative of the muscle-remodeling environment was also measured via NanoString. Overall fiber size increased ~20% with cycle training (P = 0.052). MyHC I satellite cell density increased 29% in response to acute resistance exercise before endurance training and 50% with endurance training (P < 0.05). Following endurance training, MyHC I satellite cell density decreased by 13% in response to acute resistance exercise (acute resistance × training interaction, P < 0.05). Genes with an interaction effect tracked with satellite cell behavior, increasing in the untrained state and decreasing in the endurance trained state in response to resistance exercise. Similar satellite cell and gene expression response patterns indicate coordinated regulation of the muscle environment to promote adaptation. Moderate-intensity endurance cycle training modulates the response to acute resistance exercise, potentially conditioning the muscle for more intense concentric/eccentric activity. These results suggest that cycle training is an effective endurance exercise modality for promoting growth in middle-aged women, who are susceptible to muscle mass loss with progressing age. © 2016 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.

Continuous moderate-intensity exercise with or without intermittent high-intensity work: effects on acute and late glycaemia in athletes with Type 1 diabetes mellitus.

PubMed

Iscoe, K E; Riddell, M C

2011-07-01

Individuals with Type 1 diabetes mellitus are susceptible to hypoglycaemia during and after continuous moderate-intensity exercise, but hyperglycaemia during intermittent high-intensity exercise. The combination of both forms of exercise may have a moderating effect on glycaemia in recovery. The aims of this study were to compare the physiological responses and associated glycaemic changes to continuous moderate-intensity exercise vs. continuous moderate-intensity exercise + intermittent high-intensity exercise in athletes with Type 1 diabetes. Interstitial glucose levels were measured in a blinded fashion in 11 trained athletes with Type 1 diabetes during two sedentary days and during 2 days in which 45 min of afternoon continuous moderate-intensity exercise occurred either with or without intermittent high-intensity exercise. The total amount of work performed and the duration of exercise was identical between sessions. During exercise, heart rate, respiratory exchange ratio, oxygen utilization, ventilation and blood lactate levels were higher during continuous moderate-intensity + intermittent high-intensity exercise vs. continuous moderate-intensity exercise (all P < 0.05). Despite these marked cardiorespiratory differences between trials, there was no difference in the reduction of interstitial glucose or plasma glucose levels between the exercise trials. Nocturnal glucose levels were higher in continuous moderate-intensity + intermittent high-intensity exercise and in sedentary vs. continuous moderate-intensity exercise (P < 0.05). Compared with continuous moderate-intensity exercise alone, continuous moderate-intensity + intermittent high-intensity exercise was associated with less post-exercise hypoglycaemia (5.2 vs. 1.5% of the time spent with glucose < 4.0 mmol/l) and more post-exercise hyperglycaemia (33.8 vs. 20.4% of time > 11.0 mmol/l). Although the decreases in glucose level during continuous moderate-intensity exercise and continuous moderate-intensity + intermittent high-intensity exercise are similar, the latter form of exercise protects against nocturnal hypoglycaemia in athletes with Type 1 diabetes. © 2011 The Authors. Diabetic Medicine © 2011 Diabetes UK.

Fueling strategies to optimize performance: training high or training low?

PubMed

Burke, L M

2010-10-01

Availability of carbohydrate as a substrate for the muscle and central nervous system is critical for the performance of both intermittent high-intensity work and prolonged aerobic exercise. Therefore, strategies that promote carbohydrate availability, such as ingesting carbohydrate before, during and after exercise, are critical for the performance of many sports and a key component of current sports nutrition guidelines. Guidelines for daily carbohydrate intakes have evolved from the "one size fits all" recommendation for a high-carbohydrate diets to an individualized approach to fuel needs based on the athlete's body size and exercise program. More recently, it has been suggested that athletes should train with low carbohydrate stores but restore fuel availability for competition ("train low, compete high"), based on observations that the intracellular signaling pathways underpinning adaptations to training are enhanced when exercise is undertaken with low glycogen stores. The present literature is limited to studies of "twice a day" training (low glycogen for the second session) or withholding carbohydrate intake during training sessions. Despite increasing the muscle adaptive response and reducing the reliance on carbohydrate utilization during exercise, there is no clear evidence that these strategies enhance exercise performance. Further studies on dietary periodization strategies, especially those mimicking real-life athletic practices, are needed. © 2010 John Wiley & Sons A/S.

Vestibular rehabilitation therapy: review of indications, mechanisms, and key exercises.

PubMed

Han, Byung In; Song, Hyun Seok; Kim, Ji Soo

2011-12-01

Vestibular rehabilitation therapy (VRT) is an exercise-based treatment program designed to promote vestibular adaptation and substitution. The goals of VRT are 1) to enhance gaze stability, 2) to enhance postural stability, 3) to improve vertigo, and 4) to improve activities of daily living. VRT facilitates vestibular recovery mechanisms: vestibular adaptation, substitution by the other eye-movement systems, substitution by vision, somatosensory cues, other postural strategies, and habituation. The key exercises for VRT are head-eye movements with various body postures and activities, and maintaining balance with a reduced support base with various orientations of the head and trunk, while performing various upper-extremity tasks, repeating the movements provoking vertigo, and exposing patients gradually to various sensory and motor environments. VRT is indicated for any stable but poorly compensated vestibular lesion, regardless of the patient's age, the cause, and symptom duration and intensity. Vestibular suppressants, visual and somatosensory deprivation, immobilization, old age, concurrent central lesions, and long recovery from symptoms, but there is no difference in the final outcome. As long as exercises are performed several times every day, even brief periods of exercise are sufficient to facilitate vestibular recovery. Here the authors review the mechanisms and the key exercises for each of the VRT goals.

Vestibular Rehabilitation Therapy: Review of Indications, Mechanisms, and Key Exercises

PubMed Central

Song, Hyun Seok; Kim, Ji Soo

2011-01-01

Vestibular rehabilitation therapy (VRT) is an exercise-based treatment program designed to promote vestibular adaptation and substitution. The goals of VRT are 1) to enhance gaze stability, 2) to enhance postural stability, 3) to improve vertigo, and 4) to improve activities of daily living. VRT facilitates vestibular recovery mechanisms: vestibular adaptation, substitution by the other eye-movement systems, substitution by vision, somatosensory cues, other postural strategies, and habituation. The key exercises for VRT are head-eye movements with various body postures and activities, and maintaining balance with a reduced support base with various orientations of the head and trunk, while performing various upper-extremity tasks, repeating the movements provoking vertigo, and exposing patients gradually to various sensory and motor environments. VRT is indicated for any stable but poorly compensated vestibular lesion, regardless of the patient's age, the cause, and symptom duration and intensity. Vestibular suppressants, visual and somatosensory deprivation, immobilization, old age, concurrent central lesions, and long recovery from symptoms, but there is no difference in the final outcome. As long as exercises are performed several times every day, even brief periods of exercise are sufficient to facilitate vestibular recovery. Here the authors review the mechanisms and the key exercises for each of the VRT goals. PMID:22259614

Role of fat metabolism in exercise.

PubMed

Askew, E W

1984-07-01

Fat and carbohydrate are the two major energy sources used during exercise. Either source can predominate, depending upon the duration and intensity of exercise, degree of prior physical conditioning, and the composition of the diet consumed in the days prior to a bout of exercise. Fatty acid oxidation can contribute 50 to 60 per cent of the energy expenditure during a bout of low intensity exercise of long duration. Strenuous submaximal exercise requiring 65 to 80 per cent of VO2 max will utilize less fat (10 to 45 per cent of the energy expended). Exercise training is accompanied by metabolic adaptations that occur in skeletal muscle and adipose tissue and that facilitate a greater delivery and oxidation of fatty acids during exercise. The trained state is characterized by an increased flux of fatty acids through smaller pools of adipose tissue energy. This is reflected by smaller, more metabolically active adipose cells in smaller adipose tissue depots. Peak blood concentrations of free fatty acids and ketone bodies are lower during and following exercise in trained individuals, probably due to increased capacity of the skeletal musculature to oxidize these energy sources. Trained individuals oxidize more fat and less carbohydrate than untrained subjects when performing submaximal work of the same absolute intensity. This increased capacity to utilize energy from fat conserves crucial muscle and liver glycogen stores and can contribute to increased endurance. Further benefits of the enhanced lipid metabolism accompanying chronic aerobic exercise training are decreased cardiac risk factors. Exercise training results in lower blood cholesterol and triglycerides and increased high density lipoprotein cholesterol. High-fat diets are not recommended because of their association with atherosclerotic heart disease. Recent evidence suggests that low-fat high-carbohydrate diets may increase blood triglycerides and reduce high density lipoproteins. This suggests that the chronic ingestion of diets that are extreme in their composition of either fat or carbohydrate should be approached with caution in health-conscious athletes, as well as in sedentary individuals.

The psychosocial impact of exercising with epilepsy: A narrative analysis.

PubMed

Collard, Sarah S; Marlow, Caroline

2016-08-01

Research has presented the benefits of and barriers to exercise for people with epilepsy through quantitative means. However, individual experiences through qualitative investigations have been absent. This research will present the narratives of people with epilepsy exercising over time and, as a result, develop further understanding of the psychosocial impact of exercising with epilepsy. Four interviews were conducted over the course of one year (one every three to four months) with four participants (aged 23-38years) who varied in seizure type and control (16 interviews in total). A narrative analysis was used to analyze their exercise experiences. Results showed that exercise creates a positive effect on psychological and physical well-being. However, prevention from exercise as a result of medical advice or recurrent seizures can create negative effects such as social isolation, anxiety, lack of confidence, frustration, and anger. Adaptations of decreasing exercise intensity level and partaking in different physical activities are techniques used to lessen the negative impact and maintain an exercise routine. Time was shown to be an important factor in this adaptation as well as portrayed the cyclical responses of negative and positive emotions in regard to their exercise life. These findings provide valuable insight into the psychosocial benefits of and barriers to exercising with epilepsy and draw attention to the individual differences in how a person with epilepsy copes with uncontrolled seizures and their impact on his/her exercise routine. This knowledge can lead to future research in exploring how a person with epilepsy can overcome these barriers to exercise and encourage more people with epilepsy to enjoy the benefits of exercise. Copyright © 2016 Elsevier Inc. All rights reserved.

Effects of allopurinol on exercise-induced muscle damage: new therapeutic approaches?

PubMed

Sanchis-Gomar, F; Pareja-Galeano, H; Perez-Quilis, C; Santos-Lozano, A; Fiuza-Luces, C; Garatachea, N; Lippi, G; Lucia, A

2015-01-01

Intensive muscular activity can trigger oxidative stress, and free radicals may hence be generated by working skeletal muscle. The role of the enzyme xanthine oxidase as a generating source of free radicals is well documented and therefore is involved in the skeletal muscle damage as well as in the potential transient cardiovascular damage induced by high-intensity physical exercise. Allopurinol is a purine hypoxanthine-based structural analog and a well-known inhibitor of xanthine oxidase. The administration of the xanthine oxidase inhibitor allopurinol may hence be regarded as promising, safe, and an economic strategy to decrease transient skeletal muscle damage (as well as heart damage, when occurring) in top-level athletes when administered before a competition or a particularly high-intensity training session. Although continuous administration of allopurinol in high-level athletes is not recommended due to its possible role in hampering training-induced adaptations, the drug might be useful in non-athletes. Exertional rhabdomyolysis is the most common form of rhabdomyolysis and affects individuals participating in a type of intense exercise to which they are not accustomed. This condition can cause exercise-related myoglobinuria, thus increasing the risk of acute renal failure and is also associated with sickle cell trait. In this manuscript, we have reviewed the recent evidence about the effects of allopurinol on exercise-induced muscle damage. More research is needed to determine whether allopurinol may be useful for preventing not only exertional rhabdomyolysis and acute renal damage but also skeletal muscle wasting in critical illness as well as in immobilized, bedridden, sarcopenic or cachectic patients.

The effects of three different exercise modalities on markers of male reproduction in healthy subjects: a randomized controlled trial.

PubMed

Hajizadeh Maleki, Behzad; Tartibian, Bakhtyar; Chehrazi, Mohammad

2017-02-01

The aim of this study was to investigate the effects of moderate-intensity continuous training (MICT), high-intensity continuous training (HICT) and high-intensity interval training (HIIT) on markers of male reproduction including seminal markers of oxidative stress and inflammation as well as semen quality and sperm DNA integrity in healthy human subjects. A total of 397 healthy male volunteers were screened and 280 were randomly assigned to one of the MICT (n = 70), HICT (n = 70), HIIT (n = 70) and non-exercise (NON-EX, n = 70) groups. Subjects had inflammatory markers (IL-1β, IL-6, IL-8 and TNF-α), oxidants (ROS, MDA and 8-isoprostane), antioxidants (SOD, catalase and TAC), semen parameters and sperm DNA damage measured at baseline (T 1 ), the end of week 12 (T 2 ), the end of week 24 (T 3 ), and 7 (T 4 ) and 30 days (T 5 ) after training. Chronic MICT, HICT and HIIT attenuated seminal markers of oxidative stress and inflammation with different kinetics for the three types of exercise (P < 0.05), and these changes were correlated with favorable improvements in semen quality parameters and sperm DNA integrity (P < 0.05). MICT was superior to HICT and HIIT in the improvements of markers of male reproductive function (P < 0.05). In conclusion, different exercise modalities favorably affect markers of male reproduction with different kinetics, suggesting intensity-, duration- and type-dependent adaptations to exercise training in healthy human subjects. © 2017 Society for Reproduction and Fertility.

Adaptation of exercise ventilation during an actively-induced hyperthermia following passive heat acclimation.

PubMed

Beaudin, Andrew E; Clegg, Miriam E; Walsh, Michael L; White, Matthew D

2009-09-01

Hyperthermia-induced hyperventilation has been proposed to be a human thermolytic thermoregulatory response and to contribute to the disproportionate increase in exercise ventilation (VE) relative to metabolic needs during high-intensity exercise. In this study it was hypothesized that VE would adapt similar to human eccrine sweating (E(SW)) following a passive heat acclimation (HA). All participants performed an incremental exercise test on a cycle ergometer from rest to exhaustion before and after a 10-day passive exposure for 2 h/day to either 50 degrees C and 20% relative humidity (RH) (n = 8, Acclimation group) or 24 degrees C and 32% RH (n = 4, Control group). Attainment of HA was confirmed by a significant decrease (P = 0.025) of the esophageal temperature (T(es)) threshold for the onset of E(SW) and a significantly elevated E(SW) (P < or = 0.040) during the post-HA exercise tests. HA also gave a significant decrease in resting T(es) (P = 0.006) and a significant increase in plasma volume (P = 0.005). Ventilatory adaptations during exercise tests following HA included significantly decreased T(es) thresholds (P < or = 0.005) for the onset of increases in the ventilatory equivalents for O(2) (VE/VO(2)) and CO(2) (VE/VCO(2)) and a significantly increased VE (P < or = 0.017) at all levels of T(es). Elevated VE was a function of a significantly greater tidal volume (P = 0.003) at lower T(es) and of breathing frequency (P < or = 0.005) at higher T(es). Following HA, the ventilatory threshold was uninfluenced and the relationships between VO(2) and either VE/VO(2) or VE/VCO(2) did not explain the resulting hyperventilation. In conclusion, the results support that exercise VE following passive HA responds similarly to E(SW), and the mechanism accounting for this adaptation is independent of changes of the ventilatory threshold or relationships between VO(2) with each of VE/VO(2) and VE/VCO(2).

High-intensity interval exercise training for public health: a big HIT or shall we HIT it on the head?

PubMed

Biddle, Stuart J H; Batterham, Alan M

2015-07-18

The efficacy of high-intensity interval training for a broad spectrum of cardio-metabolic health outcomes is not in question. Rather, the effectiveness of this form of exercise is at stake. In this paper we debate the issues concerning the likely success or failure of high-intensity interval training interventions for population-level health promotion. Biddle maintains that high-intensity interval training cannot be a viable public health strategy as it will not be adopted or maintained by many people. This conclusion is based on an analysis of perceptions of competence, the psychologically aversive nature of high-intensity exercise, the affective component of attitudes, the less conscious elements of motivated behaviour that reflect our likes and dislikes, and analysis using the RE-AIM framework. Batterham argues that this appraisal is based on a constrained and outmoded definition of high-intensity interval training and that truly practical and scalable protocols have been - and continue to be - developed. He contends that the purported displeasure associated with this type of exercise has been overstated. Biddle suggests that the way forward is to help the least active become more active rather than the already active to do more. Batterham claims that traditional physical activity promotion has been a spectacular failure. He proposes that, within an evolutionary health promotion framework, high-intensity interval training could be a successful population strategy for producing rapid physiological adaptations benefiting public health, independent of changes in total physical activity energy expenditure. Biddle recommends that we focus our attention elsewhere if we want population-level gains in physical activity impacting public health. His conclusion is based on his belief that high-intensity interval training interventions will have limited reach, effectiveness, and adoption, and poor implementation and maintenance. In contrast, Batterham maintains that there is genuine potential for scalable, enjoyable high-intensity interval exercise interventions to contribute substantially to addressing areas of public health priority, including prevention and treatment of Type 2 diabetes and cardiovascular disease.

Application of the Speed-Duration Relationship to Normalize the Intensity of High-Intensity Interval Training

PubMed Central

Ferguson, Carrie; Wilson, John; Birch, Karen M.; Kemi, Ole J.

2013-01-01

The tolerable duration of continuous high-intensity exercise is determined by the hyperbolic Speed-tolerable duration (S-tLIM) relationship. However, application of the S-tLIM relationship to normalize the intensity of High-Intensity Interval Training (HIIT) has yet to be considered, with this the aim of present study. Subjects completed a ramp-incremental test, and series of 4 constant-speed tests to determine the S-tLIM relationship. A sub-group of subjects (n = 8) then repeated 4 min bouts of exercise at the speeds predicted to induce intolerance at 4 min (WR4), 6 min (WR6) and 8 min (WR8), interspersed with bouts of 4 min recovery, to the point of exercise intolerance (fixed WR HIIT) on different days, with the aim of establishing the work rate that could be sustained for 960 s (i.e. 4×4 min). A sub-group of subjects (n = 6) also completed 4 bouts of exercise interspersed with 4 min recovery, with each bout continued to the point of exercise intolerance (maximal HIIT) to determine the appropriate protocol for maximizing the amount of high-intensity work that can be completed during 4×4 min HIIT. For fixed WR HIIT tLIM of HIIT sessions was 399±81 s for WR4, 892±181 s for WR6 and 1517±346 s for WR8, with total exercise durations all significantly different from each other (P<0.050). For maximal HIIT, there was no difference in tLIM of each of the 4 bouts (Bout 1: 229±27 s; Bout 2: 262±37 s; Bout 3: 235±49 s; Bout 4: 235±53 s; P>0.050). However, there was significantly less high-intensity work completed during bouts 2 (153.5±40. 9 m), 3 (136.9±38.9 m), and 4 (136.7±39.3 m), compared with bout 1 (264.9±58.7 m; P>0.050). These data establish that WR6 provides the appropriate work rate to normalize the intensity of HIIT between subjects. Maximal HIIT provides a protocol which allows the relative contribution of the work rate profile to physiological adaptations to be considered during alternative intensity-matched HIIT protocols. PMID:24244266

Effect of exercise on thicknesses of mature hyaline cartilage, calcified cartilage, and subchondral bone of equine tarsi.

PubMed

Tranquille, Carolyne A; Blunden, Antony S; Dyson, Sue J; Parkin, Tim D H; Goodship, Allen E; Murray, Rachel C

2009-12-01

OBJECTIVE-To investigate effects of exercise on hyaline cartilage (HC), calcified cartilage (CC), and subchondral bone (SCB) thickness patterns of equine tarsi. SAMPLE POPULATION-30 tarsi from cadavers of horses with known exercise history. PROCEDURES-Tarsi were assigned to 3 groups according to known exercise history as follows: pasture exercise only (PE tarsi), low-intensity general-purpose riding exercise (LE tarsi), and high-intensity elite competition riding exercise (EE tarsi). Osteochondral tissue from distal tarsal joints underwent histologic preparation. Hyaline cartilage, CC, and SCB thickness were measured at standard sites at medial, midline, and lateral locations across joints with a histomorphometric technique. RESULTS-HC, CC, and SCB thickness were significantly greater at all sites in EE tarsi, compared with PE tarsi; this was also true when LE tarsi were compared with PE tarsi. At specific sites, HC, CC, and SCB were significantly thicker in EE tarsi, compared with LE tarsi. Along the articular surface of the proximal aspect of the third metatarsal bone, SCB was thickest in EE tarsi and thinnest in LE tarsi; increases were greatest at sites previously reported to undergo peak strains and osteochondral damage. CONCLUSIONS AND CLINICAL RELEVANCE-Increased exercise was associated with increased HC, CC, and SCB thickness in mature horses. At sites that undergo high compressive strains, with a reported predisposition to osteoarthritic change, there was increased CC and SCB thickness. These results may provide insight into the interaction between adaptive response to exercise and pathological change.

Homeostasis of exercise hyperpnea and optimal sensorimotor integration: the internal model paradigm.

PubMed

Poon, Chi-Sang; Tin, Chung; Yu, Yunguo

2007-10-15

Homeostasis is a basic tenet of biomedicine and an open problem for many physiological control systems. Among them, none has been more extensively studied and intensely debated than the dilemma of exercise hyperpnea - a paradoxical homeostatic increase of respiratory ventilation that is geared to metabolic demands instead of the normal chemoreflex mechanism. Classical control theory has led to a plethora of "feedback/feedforward control" or "set point" hypotheses for homeostatic regulation, yet so far none of them has proved satisfactory in explaining exercise hyperpnea and its interactions with other respiratory inputs. Instead, the available evidence points to a far more sophisticated respiratory controller capable of integrating multiple afferent and efferent signals in adapting the ventilatory pattern toward optimality relative to conflicting homeostatic, energetic and other objectives. This optimality principle parsimoniously mimics exercise hyperpnea, chemoreflex and a host of characteristic respiratory responses to abnormal gas exchange or mechanical loading/unloading in health and in cardiopulmonary diseases - all without resorting to a feedforward "exercise stimulus". Rather, an emergent controller signal encoding the projected metabolic level is predicted by the principle as an exercise-induced 'mental percept' or 'internal model', presumably engendered by associative learning (operant conditioning or classical conditioning) which achieves optimality through continuous identification of, and adaptation to, the causal relationship between respiratory motor output and resultant chemical-mechanical afferent feedbacks. This internal model self-tuning adaptive control paradigm opens a new challenge and exciting opportunity for experimental and theoretical elucidations of the mechanisms of respiratory control - and of homeostatic regulation and sensorimotor integration in general.

Low-intensity training provokes adaptive extracellular matrix turnover of a muscular dystrophy model

PubMed Central

Gaiad, Thaís P.; Oliveira, Murilo X.; Lobo, Adalfredo R.; Libório, Lívia R.; Pinto, Priscilla A.F.; Fernandes, Danielle C.; Santos, Ana Paula; Ambrósio, Carlos Eduardo; Machado, Alex Sander D.

2017-01-01

Recommendations of therapeutic exercise in Duchenne muscular dystrophy are still controversial. The hypothesis that a low-intensity training (LIT) protocol leads to muscle adaptations on mdx mice model was tested. Dystrophic male mice with 8 weeks old were separated in exercised (mdxE, n= 8) and sedentary (mdxC, n= 8) groups. Wild-type mice were used as control (WT, n= 8) group. Exercised group underwent a LIT protocol (9 m/min, 30 min, 3 days/wk, 60 days) on a horizontal treadmill. At day 60 all animals were analyzed regarding parameters of markers of muscle lesion and extracellular matrix turnover of muscle tissue by collagens fibers on tibial anterior muscle. Histomorphometry attested that centrally located nuclei fibers and the coefficient of variance of minimal Feret’s diameter was similar in mdxE and mdxC groups (P= 1.000) and both groups presented higher mean values than WT group (P< 0.001). Fraction area of collagen fibers of mdxE group was lower than mdxC group (P= 0,027) and similar to WT group (P= 0,751). Intramuscular area of Col3 of the mdxE group was higher than mdxC and WT groups (P<0.001). Intramuscular area of Col1 on the mdxE group was similar to the mdxC group (P= 1.000) and both groups were higher than WT group (P< 0.001). LIT protocol had not influenced muscle injuries resulting from the dystrophin-deficiency membrane fragility. Although, LIT had provoked adaptations on extracellular matrix bringing higher elastic feature to dystrophic muscle tissue. PMID:29326902

Cholinergic stimulation with pyridostigmine protects against exercise induced myocardial ischaemia

PubMed Central

Castro, R R T; Porphirio, G; Serra, S M; Nóbrega, A C L

2004-01-01

Objective: To determine the acute effects of pyridostigmine bromide, a reversible cholinesterase inhibitor, during exercise in patients with coronary artery disease. Design: Double blind, randomised, placebo controlled, crossover study. Setting: Outpatients evaluated in an exercise test laboratory. Patients: 15 patients with exercise induced myocardial ischaemia. Interventions: Maximal cardiopulmonary exercise test on a treadmill according to an individualised ramp protocol on three days. The first day was used for adaptation to the equipment and to determine exercise tolerance and the presence of exercise induced ischaemia. On the other two days, the cardiopulmonary exercise test was performed two hours after oral administration of pyridostigmine (45 mg) or placebo. All patients were taking their usual medication during the experiments. Main outcome measures: Rate–pressure product and oxygen uptake during exercise. Results: Pyridostigmine inhibited the submaximum chronotropic response (p  =  0.001), delaying the onset of myocardial ischaemia, which occurred at a similar rate–pressure product (mean (SE) placebo 20.55 (1.08) mm Hg × beats/min 103; pyridostigmine 19.75 (1.28) mm Hg × beats/min 103; p  =  0.27) but at a higher exercise intensity (oxygen consumption: placebo 18.6 (1.7) ml/kg/min; pyridostigmine 19.6 (1.8) ml/kg/min; p  =  0.03). Also, pyridostigmine increased peak oxygen consumption (placebo 23.6 (2) ml/kg/min; pyridostigmine 24.8 (2) ml/kg/min; p  =  0.01) and peak oxygen pulse (placebo 12.9 (1) ml/beat; pyridostigmine 13.6 (1) ml/beat; p  =  0.02). Conclusions: Pyridostigmine improved peak exercise tolerance and inhibited the chronotropic response to submaximum exercise, increasing the intensity at which myocardial ischaemia occurred. These results suggest that pyridostigmine can protect against exercise induced myocardial ischaemia. PMID:15367503

Hyperventilation-induced hypocapnic alkalosis slows the adaptation of pulmonary O2 uptake during the transition to moderate-intensity exercise.

PubMed

Chin, Lisa M K; Leigh, Ryan J; Heigenhauser, George J F; Rossiter, Harry B; Paterson, Donald H; Kowalchuk, John M

2007-08-15

The effect of voluntary hyperventilation-induced hypocapnic alkalosis (RALK) on pulmonary O2 uptake (VO2) kinetics and muscle deoxygenation was examined in young male adults (n=8) during moderate-intensity exercise. Subjects performed five repetitions of a step-transition in work rate from 20 W cycling to a work rate corresponding to 90% of the estimated lactate threshold during control (CON; PET,CO2, approximately 40 mmHg) and during hyperventilation (RALK; PET,CO2, approximately 20 mmHg). was measured breath-by-breath and relative concentration changes in muscle deoxy- (DeltaHHb), oxy- (DeltaO2Hb) and total (DeltaHbtot) haemoglobin were measured continuously using near-infrared (NIR) spectroscopy (Hamamatsu, NIRO 300). The time constant for the fundamental, phase 2, VO2 response (tau VO2) was greater (P<0.05) in RALK (48+/-11 s) than CON (31+/-9 s), while tauHHb was similar between conditions (RALK, 12+/-4 s; CON, 11+/-4 s). The DeltaHb(tot) was lower (P<0.05) in RALK than CON, prior to (RALK, -3+/-5 micromol l(-1); CON, -1+/-4 micromol l(-1)) and at the end (RALK, 1+/-6 micromol l(-1); CON, 5+/-5 micromol l(-1)) of moderate-intensity exercise. Although slower adaptation of during RALK may be related to an attenuated activation of PDH (and other enzymes) and provision of oxidizable substrate to the mitochondria (i.e. metabolic inertia), the present findings also suggest a role for a reduction in local muscle perfusion and O2 delivery.

Right ventricular metabolic adaptations to high-intensity interval and moderate-intensity continuous training in healthy middle-aged men.

PubMed

Heiskanen, Marja A; Leskinen, Tuija; Heinonen, Ilkka H A; Löyttyniemi, Eliisa; Eskelinen, Jari-Joonas; Virtanen, Kirsi; Hannukainen, Jarna C; Kalliokoski, Kari K

2016-09-01

Despite the recent studies on structural and functional adaptations of the right ventricle (RV) to exercise training, adaptations of its metabolism remain unknown. We investigated the effects of short-term, high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) on RV glucose and fat metabolism. Twenty-eight untrained, healthy 40-55 yr-old-men were randomized into HIIT (n = 14) and MICT (n = 14) groups. Subjects performed six supervised cycle ergometer training sessions within 2 wk (HIIT session: 4-6 × 30 s all-out cycling/4-min recovery; MICT session: 40-60 min at 60% peak O2 uptake). Primary outcomes were insulin-stimulated RV glucose uptake (RVGU) and fasted state RV free fatty acid uptake (RVFFAU) measured by positron emission tomography. Secondary outcomes were changes in RV structure and function, determined by cardiac magnetic resonance. RVGU decreased after training (-22% HIIT, -12% MICT, P = 0.002 for training effect), but RVFFAU was not affected by the training (P = 0.74). RV end-diastolic and end-systolic volumes, respectively, increased +5 and +7% for HIIT and +4 and +8% for MICT (P = 0.002 and 0.005 for training effects, respectively), but ejection fraction mildly decreased (-2% HIIT, -4% MICT, P = 0.034 for training effect). RV mass and stroke volume remained unaltered. None of the observed changes differed between the training groups (P > 0.12 for group × training interaction). Only 2 wk of physical training in previously sedentary subjects induce changes in RV glucose metabolism, volumes, and ejection fraction, which precede exercise-induced hypertrophy of RV. Copyright © 2016 the American Physiological Society.

Exergaming boxing versus heavy-bag boxing: are these equipotent for individuals with spinal cord injury?

PubMed

Mat Rosly, Maziah; Mat Rosly, Hadi; Hasnan, Nazirah; Davis, Glen M; Husain, Ruby

2017-08-01

Current strategies for increased physical activity and exercise in individuals with spinal cord injury (SCI) face many challenges with regards to maintaining their continuity of participation. Barriers cited often include problems with accessing facilities, mundane, monotonous or boring exercises and expensive equipment that is often not adapted for wheelchair users. To compare the physiological responses and user preferences between conventional heavy-bag boxing against a novel form of video game boxing, known as exergaming boxing. Cross-sectional study. Exercise laboratory setting in a university medical center. Seventeen participants with SCI were recruited, of which sixteen were male and only one female. Their mean age was 35.6±10.2 years. All of them performed a 15-minute physical exercise session of exergaming and heavy-bag boxing in a sitting position. The study assessed physiological responses in terms of oxygen consumption, metabolic equivalent (MET) and energy expenditure between exergaming and heavy-bag boxing derived from open-circuit spirometry. Participants also rated their perceived exertion using Borg's category-ratio ratings of perceived exertion. Both exergaming (MET: 4.3±1.0) and heavy-bag boxing (MET: 4.4±1.0) achieved moderate exercise intensities in these participants with SCI. Paired t-test revealed no significant differences (P>0.05, Cohen's d: 0.02-0.49) in the physiological or perceived exertional responses between the two modalities of boxing. Post session user survey reported all the participants found exergaming boxing more enjoyable. Exergaming boxing, was able to produce equipotent physiological responses as conventional heavy-bag boxing. The intensity of both exercise modalities achieved recommended intensities for health and fitness benefits. Exergaming boxing have the potential to provide an enjoyable, self-competitive environment for moderate-vigorous exercise even at the comfort of their homes.

Systematic review: the impact of exercise on mesenteric blood flow and its implication for preoperative rehabilitation.

PubMed

Knight, K A; Moug, S J; West, M A

2017-03-01

Exercise in the preoperative period, or prehabilitation, continues to evolve as an important tool in optimising patients awaiting major intra-abdominal surgery. It has been shown to reduce rates of post-operative morbidity and length of hospital stay. The mechanism by which this is achieved remains poorly understood. Adaptations in mesenteric flow in response to exercise may play a role in improving post-operative recovery by reducing rates of ileus and anastomotic leak. To systematically review the existing literature to clarify the impact of exercise on mesenteric arterial blood flow using Doppler ultrasound. PubMed, EMBASE and the Cochrane library were systematically searched to identify clinical trials using Doppler ultrasound to investigate the effect of exercise on flow through the superior mesenteric artery (SMA). Data were extracted including participant characteristics, frequency, intensity, timing and type of exercise and the effect on SMA flow. The quality of each study was assessed using the Downs and Black checklist. Sixteen studies, comprising 305 participants in total, were included. Methodological quality was generally poor. Healthy volunteers were used in twelve studies. SMA flow was found to be reduced in response to exercise in twelve studies, increased in one and unchanged in two studies. Clinical heterogeneity precluded a meta-analysis. The weight of evidence suggests that superior mesenteric arterial flow is reduced immediately following exercise. Differences in frequency, intensity, timing and type of exercise make a consensus difficult. Further studies are warranted to provide a definitive understanding of the impact of exercise on mesenteric flow.

Exercise-intensity dependent alterations in plasma redox status do not reflect skeletal muscle redox-sensitive protein signaling.

PubMed

Parker, Lewan; Trewin, Adam; Levinger, Itamar; Shaw, Christopher S; Stepto, Nigel K

2018-04-01

Redox homeostasis and redox-sensitive protein signaling play a role in exercise-induced adaptation. The effects of sprint-interval exercise (SIE), high-intensity interval exercise (HIIE) and continuous moderate-intensity exercise (CMIE), on post-exercise plasma redox status are unclear. Furthermore, whether post-exercise plasma redox status reflects skeletal muscle redox-sensitive protein signaling is unknown. In a randomized crossover design, eight healthy adults performed a cycling session of HIIE (5×4min at 75% W max ), SIE (4×30s Wingate's), and CMIE work-matched to HIIE (30min at 50% of W max ). Plasma hydrogen peroxide (H 2 O 2 ), thiobarbituric acid reactive substances (TBARS), superoxide dismutase (SOD) activity, and catalase activity were measured immediately post, 1h, 2h and 3h post-exercise. Plasma redox status biomarkers were correlated with phosphorylation of skeletal muscle p38-MAPK, JNK, NF-κB, and IκBα protein content immediately and 3h post-exercise. Plasma catalase activity was greater with SIE (56.6±3.8Uml -1 ) compared to CMIE (42.7±3.2, p<0.01) and HIIE (49.0±5.5, p=0.07). Peak plasma H 2 O 2 was significantly (p<0.05) greater after SIE (4.6±0.6nmol/ml) and HIIE (4.1±0.4) compared to CMIE (3.3±0.5). Post-exercise plasma TBARS and SOD activity significantly (p<0.05) decreased irrespective of exercise protocol. A significant positive correlation was detected between plasma catalase activity and skeletal muscle p38-MAPK phosphorylation 3h post-exercise (r=0.40, p=0.04). No other correlations were detected (all p>0.05). Low-volume SIE elicited greater post-exercise plasma catalase activity compared to HIIE and CMIE, and greater H 2 O 2 compared to CMIE. Plasma redox status did not, however, adequately reflect skeletal muscle redox-sensitive protein signaling. Copyright © 2017 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Exercise-induced oxidative stress and hypoxic exercise recovery.

PubMed

Ballmann, Christopher; McGinnis, Graham; Peters, Bridget; Slivka, Dustin; Cuddy, John; Hailes, Walter; Dumke, Charles; Ruby, Brent; Quindry, John

2014-04-01

Hypoxia due to altitude diminishes performance and alters exercise oxidative stress responses. While oxidative stress and exercise are well studied, the independent impact of hypoxia on exercise recovery remains unknown. Accordingly, we investigated hypoxic recovery effects on post-exercise oxidative stress. Physically active males (n = 12) performed normoxic cycle ergometer exercise consisting of ten high:low intensity intervals, 20 min at moderate intensity, and 6 h recovery at 975 m (normoxic) or simulated 5,000 m (hypoxic chamber) in a randomized counter-balanced cross-over design. Oxygen saturation was monitored via finger pulse oximetry. Blood plasma obtained pre- (Pre), post- (Post), 2 h post- (2Hr), 4 h post- (4Hr), and 6 h (6Hr) post-exercise was assayed for Ferric Reducing Ability of Plasma (FRAP), Trolox Equivalent Antioxidant Capacity (TEAC), Lipid Hydroperoxides (LOOH), and Protein Carbonyls (PC). Biopsies from the vastus lateralis obtained Pre and 6Hr were analyzed by real-time PCR quantify expression of Heme oxygenase 1 (HMOX1), Superoxide Dismutase 2 (SOD2), and Nuclear factor (euthyroid-derived2)-like factor (NFE2L2). PCs were not altered between trials, but a time effect (13 % Post-2Hr increase, p = 0.044) indicated exercise-induced blood oxidative stress. Plasma LOOH revealed only a time effect (p = 0.041), including a 120 % Post-4Hr increase. TEAC values were elevated in normoxic recovery versus hypoxic recovery. FRAP values were higher 6Hr (p = 0.045) in normoxic versus hypoxic recovery. Exercise elevated gene expression of NFE2L2 (20 % increase, p = 0.001) and SOD2 (42 % increase, p = 0.003), but hypoxic recovery abolished this response. Data indicate that recovery in a hypoxic environment, independent of exercise, may alter exercise adaptations to oxidative stress and metabolism.

Electromyographic analysis of upper body, lower body, and abdominal muscles during advanced Swiss ball exercises.

PubMed

Marshall, Paul W M; Desai, Imtiaz

2010-06-01

Although there is now some evidence examining the use of a Swiss ball during core stability and resistance exercises, this has commonly been performed using basic or isometric exercises. There is currently no evidence examining more advanced Swiss ball exercises. The purpose of this study was to determine whether or not muscle activity measured during advanced Swiss ball exercises was at an approximate intensity recommended for strength or endurance training in advanced, or novice individuals. After a familiarization session, 14 recreationally active subjects performed 6 different "advanced" Swiss ball exercises in a randomized order. The primary dependent variables in this study were the activity levels collected from anterior deltoid, pectoralis major, rectus abdominis (RA), external obliques, lumbar erector spinae, vastus lateralis (VL), and biceps femoris using surface electromyography. All signals were normalized to maximal voluntary isometric contractions performed before testing for each muscle. The results of this study showed that the Swiss ball roll elicited muscle activity in triceps brachii (72.5+/-32.4%) and VL (83.6+/-44.2%) commensurate with the intensity recommended for strength exercises in advanced trainers. Rectus abdominis activity was greatest during the bridge exercise (61.3+/-28.5%, p

Comparison of Psychological and Physiological Responses to Imposed vs. Self-selected High-Intensity Interval Training.

PubMed

Kellogg, Erin; Cantacessi, Cheyann; McNamer, Olivia; Holmes, Heather; von Bargen, Robert; Ramirez, Richard; Gallagher, Daren; Vargas, Stacy; Santia, Ben; Rodriguez, Karen; Astorino, Todd A

2018-05-08

Kellogg, E, Cantacessi, C, McNamer, O, Holmes, H, von Bargen, R, Ramirez, R, Gallagher, D, Vargas, S, Santia, B, Rodriguez, K, and Astorino, TA. Comparison of psychological and physiological responses to imposed vs. self-selected high-intensity interval training. J Strength Cond Res XX(X): 000-000, 2018-High-intensity interval training elicits similar physiological adaptations as moderate intensity continuous training (MICT). Some studies report greater enjoyment to a bout of high-intensity interval exercise (HIIE) vs. MICT, which is surprising considering that HIIE is more intense and typically imposed on the participant. This study compared physiological and perceptual responses between imposed and self-selected HIIE. Fourteen adults (age = 24 ± 3 years) unfamiliar with HIIE initially performed ramp exercise to exhaustion to measure maximal oxygen uptake (V[Combining Dot Above]O2max) followed by 2 subsequent sessions whose order was randomized. Imposed HIIE consisted of eight 60 seconds bouts at 80 percent peak power output (%PPO) separated by 60 seconds recovery at 10 %PPO. Self-selected HIIE (HIIESS) followed the same structure, but participants freely selected intensity in increments of 10 %PPO to achieve a rating of perceived exertion (RPE) ≥7. During exercise, heart rate, V[Combining Dot Above]O2, blood lactate concentration (BLa), affect (+5 to -5), and RPE were assessed. Physical Activity Enjoyment Scale was measured after exercise. Results showed higher V[Combining Dot Above]O2 (+10%, p = 0.013), BLa (p = 0.001), and RPE (p = 0.001) in HIIESS vs. HIIEIMP, and lower affect (p = 0.01), and enjoyment (87.6 ± 15.7 vs. 95.7 ± 11.7, p = 0.04). There was a significantly higher power output in self-selected vs. imposed HIIE (263.9 ± 81.4 W vs. 225.2 ± 59.6 W, p < 0.001). Data suggest that intensity mediates affective responses rather than the mode of HIIE performed by the participant.

Muscle changes with eccentric exercise: Implications on earth and in space

NASA Technical Reports Server (NTRS)

Hargens, Alan R.; Parazynski, Scott; Aratow, Michael; Friden, Jan

1989-01-01

Recent investigations of fluid pressure, morpholo gy, and enzyme activities of skeletal muscle exercised eccentrically or concentrically in normal human subjects are reviewed. Intramuscular pressures were measured before, during, and after submaximal exercise and correlated with subjective muscle soreness, fiber size, water content, and blood indices of muscle enzymes. High intensity eccentric exercise is characterized by post exercise pain, elevated intramuscular pressures, and swelling of both type 1 and 2 fibers as compared to concentric exercise. Thus, long periods of unaccustomed, high level eccentric contraction may cause muscle injury, fiber swelling, fluid accumulation, elevated intramuscular pressure, and delayed muscle soreness. Training regimens of progressively increasing eccentric exercise, however, cause less soreness and are extremely efficacious in increasing muscle mass and strength. It is proposed that on Earth, postural muscles are uniquely adapted to low levels of prolonged eccentric contraction that are absent during weightlessness. The almost complete absence of eccentric exercise in space may be an important contributor to muscle atrophy and therefore equipment should be designed to integrate eccentric contractions into exercise protocols for long-term spaceflight.

Improvements in exercise performance with high-intensity interval training coincide with an increase in skeletal muscle mitochondrial content and function.

PubMed

Jacobs, Robert Acton; Flück, Daniela; Bonne, Thomas Christian; Bürgi, Simon; Christensen, Peter Møller; Toigo, Marco; Lundby, Carsten

2013-09-01

Six sessions of high-intensity interval training (HIT) are sufficient to improve exercise capacity. The mechanisms explaining such improvements are unclear. Accordingly, the aim of this study was to perform a comprehensive evaluation of physiologically relevant adaptations occurring after six sessions of HIT to determine the mechanisms explaining improvements in exercise performance. Sixteen untrained (43 ± 6 ml·kg(-1)·min(-1)) subjects completed six sessions of repeated (8-12) 60 s intervals of high-intensity cycling (100% peak power output elicited during incremental maximal exercise test) intermixed with 75 s of recovery cycling at a low intensity (30 W) over a 2-wk period. Potential training-induced alterations in skeletal muscle respiratory capacity, mitochondrial content, skeletal muscle oxygenation, cardiac capacity, blood volumes, and peripheral fatigue resistance were all assessed prior to and again following training. Maximal measures of oxygen uptake (Vo2peak; ∼8%; P = 0.026) and cycling time to complete a set amount of work (∼5%; P = 0.008) improved. Skeletal muscle respiratory capacities increased, most likely as a result of an expansion of skeletal muscle mitochondria (∼20%, P = 0.026), as assessed by cytochrome c oxidase activity. Skeletal muscle deoxygenation also increased while maximal cardiac output, total hemoglobin, plasma volume, total blood volume, and relative measures of peripheral fatigue resistance were all unaltered with training. These results suggest that increases in mitochondrial content following six HIT sessions may facilitate improvements in respiratory capacity and oxygen extraction, and ultimately are responsible for the improvements in maximal whole body exercise capacity and endurance performance in previously untrained individuals.

Comparison of Acute Physiological and Psychological Responses Between Moderate Intensity Continuous Exercise and three Regimes of High Intensity Training.

PubMed

Green, Nicole; Wertz, Timothy; LaPorta, Zachary; Mora, Adam; Serbas, Jasmine; Astorino, Todd A

2017-07-19

High intensity interval training (HIIT) elicits similar physiological adaptations as moderate intensity continuous training (MICT) despite less time commitment. However, there is debate whether HIIT is more aversive than MICT. This study compared physiological and perceptual responses between MICT and three regimes of HIIT. Nineteen active adults (age = 24.0 ± 3.3 yr) unfamiliar with HIIT initially performed ramp exercise to exhaustion to measure maximal oxygen uptake (VO2 max) and determine workload for subsequent sessions, whose order was randomized. Sprint interval training (SIT) consisted of six 20 s bouts of "all-out" cycling at 140% of maximum watts (Wmax). Low volume (HIITLV) and high volume HIIT (HIITHV) consisted of eight 60 s bouts at 85% Wmax and six 2 min bouts at 70% Wmax, respectively. MICT consisted of 25 min at 40% Wmax. Across regimes, work was not matched. Heart rate, VO2, blood lactate concentration (BLa), affect, and rating of perceived exertion (RPE) were assessed during exercise. Ten minutes post-exercise, Physical Activity Enjoyment (PACES) was measured via a survey. Results revealed significantly higher (p<0.05) VO2, heart rate, BLa, and RPE in SIT, HIITLV, and HIITHV versus MICT. Despite a decline in affect during exercise (p<0.01) and significantly lower affect (p<0.05) during all HIIT regimes versus MICT at 50, 75, and 100 % of session duration, PACES was similar across regimes (p=0.65) although it was higher in women (p=0.03). Findings from healthy adults unaccustomed to interval training demonstrate that HIIT and SIT are perceived as enjoyable as MICT despite being more aversive.

Effects of acute voluntary loaded wheel running on BDNF expression in the rat hippocampus.

PubMed

Lee, Minchul; Soya, Hideaki

2017-12-31

Voluntary loaded wheel running involves the use of a load during a voluntary running activity. A muscle-strength or power-type activity performed at a relatively high intensity and a short duration may cause fewer apparent metabolic adaptations but may still elicit muscle fiber hypertrophy. This study aimed to determine the effects of acute voluntary wheel running with an additional load on brain-derived neurotrophic factor (BDNF) expression in the rat hippocampus. Ten-week old male Wistar rats were assigned randomly to a (1) sedentary (Control) group; (2) voluntary exercise with no load (No-load) group; or (3) voluntary exercise with an additional load (Load) group for 1-week (acute period). The expression of BDNF genes was quantified by real-time PCR. The average distance levels were not significantly different in the No-load and Load groups. However, the average work levels significantly increased in the Load group. The relative soleus weights were greater in the No-load group. Furthermore, loaded wheel running up-regulated the BDNF mRNA level compared with that in the Control group. The BDNF mRNA levels showed a positive correlation with workload levels (r=0.75), suggesting that the availability of multiple workload levels contributes to the BDNF-related benefits of loaded wheel running noted in this study. This novel approach yielded the first set of findings showing that acute voluntary loaded wheel running, which causes muscular adaptation, enhanced BDNF expression, suggesting a possible role of high-intensity short-term exercise in hippocampal BDNF activity. ©2017 The Korean Society for Exercise Nutrition

Physical activity in the prevention and amelioration of osteoporosis in women : interaction of mechanical, hormonal and dietary factors.

PubMed

Borer, Katarina T

2005-01-01

Osteoporosis is a serious health problem that diminishes quality of life and levies a financial burden on those who fear and experience bone fractures. Physical activity as a way to prevent osteoporosis is based on evidence that it can regulate bone maintenance and stimulate bone formation including the accumulation of mineral, in addition to strengthening muscles, improving balance, and thus reducing the overall risk of falls and fractures. Currently, our understanding of how to use exercise effectively in the prevention of osteoporosis is incomplete. It is uncertain whether exercise will help accumulate more overall peak bone mass during childhood, adolescence and young adulthood. Also, the consistent effectiveness of exercise to increase bone mass, or at least arrest the loss of bone mass after menopause, is also in question. Within this framework, section 1 introduces mechanical characteristics of bones to assist the reader in understanding their responses to physical activity. Section 2 reviews hormonal, nutritional and mechanical factors necessary for the growth of bones in length, width and mineral content that produce peak bone mass in the course of childhood and adolescence using a large sample of healthy Caucasian girls and female adolescents for reference. Effectiveness of exercise is evaluated throughout using absolute changes in bone with the underlying assumption that useful exercise should produce changes that approximate or exceed the absolute magnitude of bone parameters in a healthy reference population. Physical activity increases growth in width and mineral content of bones in girls and adolescent females, particularly when it is initiated before puberty, carried out in volumes and at intensities seen in athletes, and accompanied by adequate caloric and calcium intakes. Similar increases are seen in young women following the termination of statural growth in response to athletic training, but not to more limited levels of physical activity characteristic of longitudinal training studies. After 9-12 months of regular exercise, young adult women often show very small benefits to bone health, possibly because of large subject attrition rates, inadequate exercise intensity, duration or frequency, or because at this stage of life accumulation of bone mass may be at its natural peak. The important influence of hormones as well as dietary and specific nutrient abundance on bone growth and health are emphasised, and premature bone loss associated with dietary restriction and estradiol withdrawal in exercise-induced amenorrhoea is described. In section 3, the same assessment is applied to the effects of physical activity in postmenopausal women. Studies of postmenopausal women are presented from the perspective of limitations of the capacity of the skeleton to adapt to mechanical stress of exercise due to altered hormonal status and inadequate intake of specific nutrients. After menopause, effectiveness of exercise to increase bone mineral depends heavily on adequate availability of dietary calcium. Relatively infrequent evidence that physical activity prevents bone loss or increases bone mineral after menopause may be a consequence of inadequate calcium availability or low intensity of exercise in training studies. Several studies with postmenopausal women show modest increases in bone mineral toward the norm seen in a healthy population in response to high-intensity training. Physical activities continue to stimulate increases in bone diameter throughout the lifespan. These exercise-stimulated increases in bone diameter diminish the risk of fractures by mechanically counteracting the thinning of bones and increases in bone porosity. Seven principles of bone adaptation to mechanical stress are reviewed in section 4 to suggest how exercise by human subjects could be made more effective. They posit that exercise should: (i) be dynamic, not static; (ii) exceed a threshold intensity; (iii) exceed a threshold strain frequency; (iv) be relatively brief but intermittent; (v) impose an unusual loading pattern on the bones; (vi) be supported by unlimited nutrient energy; and (vii) include adequate calcium and cholecalciferol (vitamin D3) availability.

One year of high-intensity interval training improves exercise capacity, but not left ventricular function in stable heart transplant recipients: a randomised controlled trial.

PubMed

Rustad, Lene A; Nytrøen, Kari; Amundsen, Brage H; Gullestad, Lars; Aakhus, Svend

2014-02-01

Heart transplant recipients have lower exercise capacity and impaired cardiac function compared with the normal population. High-intensity interval training (HIIT) improves exercise capacity and cardiac function in patients with heart failure and hypertension, but the effect on cardiac function in stable heart transplant recipients is not known. Thus, we investigated whether HIIT improved cardiac function and exercise capacity in stable heart transplant recipients by use of comprehensive rest- and exercise-echocardiography and cardiopulmonary exercise testing. Fifty-two clinically stable heart transplant recipients were randomised either to HIIT (4 × 4 minutes at 85-95% of peak heart rate three times per week for eight weeks) or to control. Three such eight-week periods were distributed throughout one year. Echocardiography (rest and submaximal exercise) and cardiopulmonary exercise testing were performed at baseline and follow-up. One year of HIIT increased VO 2peak from 27.7 ± 5.5 at baseline to 30.9 ± 5.0 ml/kg/min at follow-up, while the control group remained unchanged (28.5 ± 7.0 vs. 28.0 ± 6.7 ml/kg per min, p < 0.001 for difference between the groups). Systolic and diastolic left ventricular functions at rest and during exercise were generally unchanged by HIIT. Whereas HIIT is feasible in heart transplant recipients and effectively improves exercise capacity, it does not alter cardiac systolic and diastolic function significantly. Thus, the observed augmentation in exercise capacity is best explained by extra-cardiac adaptive mechanisms.

Exercise associated hormonal signals as powerful determinants of an effective fat mass loss.

PubMed

Bajer, B; Vlcek, M; Galusova, A; Imrich, R; Penesova, A

2015-07-01

Obesity management for achieving an effective weight loss includes dietary modification and exercise [resistance (strength), endurance (cardiovascular) or intervals training (high-intensity intermittent exercise)]. Regular exercise acutely increases fat oxidation, which induces loss of fat mass and increases energy expenditure. Moreover, it has a positive effect on the physical (improved insulin sensitivity, lipid profile, etc.) and mental health (mood, cognition, memory, sleep, etc.). Endocrine responses to muscle actions are affected by many factors, including the exercise muscle groups (lower and upper body), load/volume, time-under tension, and rest-period intervals between sets, training status, gender, and age. The aim of this review is to summarize, evaluate, and clarify the literature data focusing on the endocrine responses to different types of exercise, including the frequency, intensity, and type of movement with regard to the fat loss strategies. Many studies have investigated anabolic [growth hormone, insulin-like growth factor-1 (IGF-1), testosterone] and gluco- and appetite- regulatory (insulin, cortisol, ghrelin) hormone responses and adaptations of skeletal muscles to exercise. Muscle tissue is a critical endocrine organ, playing important role in the regulation of several physiological and metabolic events. Moreover, we are also describing the response of some other substances to exercise, such as myokines [irisin, apelin, brain-derived neurotrophic factor (BDNF), myostatin, and fibroblast growth factor 21 (FGF21)]. It is proposed that reducing intra-abdominal fat mass and increasing cardiorespiratory fitness through improving nutritional quality, reducing sedentary behavior, and increase the participation in physical activity/exercise, might be associated with clinical benefits, sometimes even in the absence of weight loss.

Parameter estimation and order selection for an empirical model of VO2 on-kinetics.

PubMed

Alata, O; Bernard, O

2007-04-27

In humans, VO2 on-kinetics are noisy numerical signals that reflect the pulmonary oxygen exchange kinetics at the onset of exercise. They are empirically modelled as a sum of an offset and delayed exponentials. The number of delayed exponentials; i.e. the order of the model, is commonly supposed to be 1 for low-intensity exercises and 2 for high-intensity exercises. As no ground truth has ever been provided to validate these postulates, physiologists still need statistical methods to verify their hypothesis about the number of exponentials of the VO2 on-kinetics especially in the case of high-intensity exercises. Our objectives are first to develop accurate methods for estimating the parameters of the model at a fixed order, and then, to propose statistical tests for selecting the appropriate order. In this paper, we provide, on simulated Data, performances of Simulated Annealing for estimating model parameters and performances of Information Criteria for selecting the order. These simulated Data are generated with both single-exponential and double-exponential models, and noised by white and Gaussian noise. The performances are given at various Signal to Noise Ratio (SNR). Considering parameter estimation, results show that the confidences of estimated parameters are improved by increasing the SNR of the response to be fitted. Considering model selection, results show that Information Criteria are adapted statistical criteria to select the number of exponentials.

Cellular Stress Response Gene Expression During Upper and Lower Body High Intensity Exercises

PubMed Central

Kochanowicz, Andrzej; Sawczyn, Stanisław; Niespodziński, Bartłomiej; Mieszkowski, Jan; Kochanowicz, Kazimierz

2017-01-01

Objectives The aim was to compare the effect of upper and lower body high-intensity exercise on chosen genes expression in athletes and non-athletes. Method Fourteen elite male artistic gymnasts (EAG) aged 20.6 ± 3.3 years and 14 physically active men (PAM) aged 19.9 ± 1.0 years performed lower and upper body 30 s Wingate Tests. Blood samples were collected before, 5 and 30 minutes after each effort to assess gene expression via PCR. Results Significantly higher mechanical parameters after lower body exercise was observed in both groups, for relative power (8.7 ± 1.2 W/kg in gymnasts, 7.2 ± 1.2 W/kg in controls, p = 0.01) and mean power (6.7 ± 0.7 W/kg in gymnasts, 5.4 ± 0.8 W/kg in controls, p = 0.01). No differences in lower versus upper body gene expression were detected for all tested genes as well as between gymnasts and physical active man. For IL-6 m-RNA time-dependent effect was observed. Conclusions Because of no significant differences in expression of genes associated with cellular stress response the similar adaptive effect to exercise may be obtained so by lower and upper body exercise. PMID:28141870

Ketone Bodies and Exercise Performance: The Next Magic Bullet or Merely Hype?

PubMed

Pinckaers, Philippe J M; Churchward-Venne, Tyler A; Bailey, David; van Loon, Luc J C

2017-03-01

Elite athletes and coaches are in a constant search for training methods and nutritional strategies to support training and recovery efforts that may ultimately maximize athletes' performance. Recently, there has been a re-emerging interest in the role of ketone bodies in exercise metabolism, with considerable media speculation about ketone body supplements being routinely used by professional cyclists. Ketone bodies can serve as an important energy substrate under certain conditions, such as starvation, and can modulate carbohydrate and lipid metabolism. Dietary strategies to increase endogenous ketone body availability (i.e., a ketogenic diet) require a diet high in lipids and low in carbohydrates for ~4 days to induce nutritional ketosis. However, a high fat, low carbohydrate ketogenic diet may impair exercise performance via reducing the capacity to utilize carbohydrate, which forms a key fuel source for skeletal muscle during intense endurance-type exercise. Recently, ketone body supplements (ketone salts and esters) have emerged and may be used to rapidly increase ketone body availability, without the need to first adapt to a ketogenic diet. However, the extent to which ketone bodies regulate skeletal muscle bioenergetics and substrate metabolism during prolonged endurance-type exercise of varying intensity and duration remains unknown. Therefore, at present there are no data available to suggest that ingestion of ketone bodies during exercise improves athletes' performance under conditions where evidence-based nutritional strategies are applied appropriately.

Adapted low intensity ergometer aerobic training for early and severely impaired stroke survivors: a pilot randomized controlled trial to explore its feasibility and efficacy.

PubMed

Wang, Zun; Wang, Lei; Fan, Hongjuan; Jiang, Wenjun; Wang, Sheng; Gu, Zhaohua; Wang, Tong

2014-09-01

[Purpose] To evaluate the feasibility and efficacy of adapted low intensity ergometer aerobic training for early and severely impaired stroke survivors. [Subjects] The subjects were forty-eight early stroke survivors. [Methods] Eligible subjects were recruited and randomly assigned to an experimental group and a control group. Both groups participated in comprehensive rehabilitation training. Low intensity aerobic training was only performed by the experimental group. Outcome measures were the Fugl-Meyer motor score, Barthel index, exercise test time, peak heart rate, plasma glucose level and serum lipid profiles. [Results] Patients in the experimental group finished 88.6% of the total aerobic training sessions prescribed. In compliant participants (adherence≥80%), aerobic training significantly improved the Barthel index (from 40.1±21.1 to 79.2±14.2), Fugl-Meyer motor score (from 26.4±19.4 to 45.4±12.7), exercise test time (from 12.2±3.62 min to 13.9±3.6 min), 2-hour glucose level (from 9.22±1.16 mmol/L to 7.21±1.36 mmol/L) and homeostasis model of assessment for insulin resistence index (from 1.72±1.01 to 1.28±0.88). [Conclusion] Preliminary findings suggest that early and severely impaired stroke patients may benefit from low intensity ergometer aerobic training.

The stress-buffering effect of acute exercise: Evidence for HPA axis negative feedback.

PubMed

Zschucke, Elisabeth; Renneberg, Babette; Dimeo, Fernando; Wüstenberg, Torsten; Ströhle, Andreas

2015-01-01

According to the cross-stressor adaptation hypothesis, physically trained individuals show lower physiological and psychological responses to stressors other than exercise, e.g. psychosocial stress. Reduced stress reactivity may constitute a mechanism of action for the beneficial effects of exercise in maintaining mental health. With regard to neural and psychoneuroendocrine stress responses, the acute stress-buffering effects of exercise have not been investigated yet. A sample of highly trained (HT) and sedentary (SED) young men was randomized to either exercise on a treadmill at moderate intensity (60-70% VO2max; AER) for 30 min, or to perform 30 min of "placebo" exercise (PLAC). 90 min later, an fMRI experiment was conducted using an adapted version of the Montreal Imaging Stress Task (MIST). The subjective and psychoneuroendocrine (cortisol and α-amylase) changes induced by the exercise intervention and the MIST were assessed, as well as neural activations during the MIST. Finally, associations between the different stress responses were analysed. Participants of the AER group showed a significantly reduced cortisol response to the MIST, which was inversely related to the previous exercise-induced α-amylase and cortisol fluctuations. With regard to the sustained BOLD signal, we found higher bilateral hippocampus (Hipp) activity and lower prefrontal cortex (PFC) activity in the AER group. Participants with a higher aerobic fitness showed lower cortisol responses to the MIST. As the Hipp and PFC are brain structures prominently involved in the regulation of the hypothalamus-pituitary-adrenal (HPA) axis, these findings indicate that the acute stress-buffering effect of exercise relies on negative feedback mechanisms. Positive affective changes after exercise appear as important moderators largely accounting for the effects related to physical fitness. Copyright © 2014 Elsevier Ltd. All rights reserved.

Adaptation of exercise-induced stress in well-trained healthy young men.

PubMed

JanssenDuijghuijsen, Lonneke M; Keijer, Jaap; Mensink, Marco; Lenaerts, Kaatje; Ridder, Lars; Nierkens, Stefan; Kartaram, Shirley W; Verschuren, Martie C M; Pieters, Raymond H H; Bas, Richard; Witkamp, Renger F; Wichers, Harry J; van Norren, Klaske

2017-01-01

What is the central question of this study? Exercise is known to induce stress-related physiological responses, such as changes in intestinal barrier function. Our aim was to determine the test-retest repeatability of these responses in well-trained individuals. What is the main finding and its importance? Responses to strenuous exercise, as indicated by stress-related markers such as intestinal integrity markers and myokines, showed high test-retest variation. Even in well-trained young men an adapted response is seen after a single repetition after 1 week. This finding has implications for the design of studies aimed at evaluating physiological responses to exercise. Strenuous exercise induces different stress-related physiological changes, potentially including changes in intestinal barrier function. In the Protégé Study (ISRCTN14236739; www.isrctn.com), we determined the test-retest repeatability in responses to exercise in well-trained individuals. Eleven well-trained men (27 ± 4 years old) completed an exercise protocol that consisted of intensive cycling intervals, followed by an overnight fast and an additional 90 min cycling phase at 50% of maximal workload the next morning. The day before (rest), and immediately after the exercise protocol (exercise) a lactulose and rhamnose solution was ingested. Markers of energy metabolism, lactulose-to-rhamnose ratio, several cytokines and potential stress-related markers were measured at rest and during exercise. In addition, untargeted urine metabolite profiles were obtained. The complete procedure (Test) was repeated 1 week later (Retest) to assess repeatability. Metabolic effect parameters with regard to energy metabolism and urine metabolomics were similar for both the Test and Retest period, underlining comparable exercise load. Following exercise, intestinal permeability (1 h plasma lactulose-to-rhamnose ratio) and the serum interleukin-6, interleukin-10, fibroblast growth factor-21 and muscle creatine kinase concentrations were significantly increased compared with rest only during the first test and not when the test was repeated. Responses to strenuous exercise in well-trained young men, as indicated by intestinal markers and myokines, show adaptation in Test-Retest outcome. This might be attributable to a carry-over effect of the defense mechanisms triggered during the Test. This finding has implications for the design of studies aimed at evaluating physiological responses to exercise. © 2016 The Authors. Experimental Physiology © 2016 The Physiological Society.

American College of Sports Medicine position stand. Exercise and hypertension.

PubMed

Pescatello, Linda S; Franklin, Barry A; Fagard, Robert; Farquhar, William B; Kelley, George A; Ray, Chester A

2004-03-01

Hypertension (HTN), one of the most common medical disorders, is associated with an increased incidence of all-cause and cardiovascular disease (CVD) mortality. Lifestyle modifications are advocated for the prevention, treatment, and control of HTN, with exercise being an integral component. Exercise programs that primarily involve endurance activities prevent the development of HTN and lower blood pressure (BP) in adults with normal BP and those with HTN. The BP lowering effects of exercise are most pronounced in people with HTN who engage in endurance exercise with BP decreasing approximately 5-7 mm HG after an isolated exercise session (acute) or following exercise training (chronic). Moreover, BP is reduced for up to 22 h after an endurance exercise bout (e.g.postexercise hypotension), with greatest decreases among those with highest baseline BP. The proposed mechanisms for the BP lowering effects of exercise include neurohumoral, vascular, and structural adaptations. Decreases in catecholamines and total peripheral resistance, improved insulin sensitivity, and alterations in vasodilators and vasoconstrictors are some of the postulated explanations for the antihypertensive effects of exercise. Emerging data suggest genetic links to the BP reductions associated with acute and chronic exercise. Nonetheless, definitive conclusions regarding the mechanisms for the BP reductions following endurance exercise cannot be made at this time. Individuals with controlled HTN and no CVD or renal complications may participated in an exercise program or competitive athletics, but should be evaluated, treated and monitored closely. Preliminary peak or symptom-limited exercise testing may be warranted, especially for men over 45 and women over 55 yr planning a vigorous exercise program (i.e. > or = 60% VO2R, oxygen uptake reserve). In the interim, while formal evaluation and management are taking place, it is reasonable for the majority of patients to begin moderate intensity exercise (40-<60% VO2R) such as walking. When pharmacological therapy is indicated in physically active people it should be, ideally: a) lower BP at rest and during exertion; b) decrease total peripheral resistance; and, c) not adversely affect exercise capacity. For these reasons, angiotensin converting enzyme (ACE) inhibitors (or angiotensin II receptor blockers in case of ACE inhibitor intolerance) and calcium channel blockers are currently the drugs of choice for recreational exercisers and athletes who have HTN. Exercise remains a cornerstone therapy for the primary prevention, treatment, and control of HTN. The optimal training frequency, intensity, time, and type (FITT) need to be better defined to optimize the BP lowering capacities of exercise, particularly in children, women, older adults, and certain ethnic groups. based upon the current evidence, the following exercise prescription is recommended for those with high BP: Frequency: on most, preferably all, days of the week. Intensity: moderate-intensity (40-<60% VO2R). Time: > or = 30 min of continuous or accumulated physical activity per day. Type: primarily endurance physical activity supplemented by resistance exercise.

Nandrolone attenuates aortic adaptation to exercise in rats.

PubMed

Sun, Mengwei; Shen, Weili; Zhong, Meifang; Wu, Pingping; Chen, Hong; Lu, Aiyun

2013-03-15

In this study, we investigated the interaction between exercise-induced mitochondrial adaptation of large vessels and the effects of chronic anabolic androgenic steroids (AASs). Four groups of Sprague-Dawley rats were studied: (i) sedentary, (ii) sedentary + nandrolone-treated, (iii) aerobic exercise trained, and (iv) trained + nandrolone-treated. Aerobic training increased the levels of aortic endothelial nitric oxide synthase (eNOS) and heme oxygenase-1 (HO-1) in accordance with improved acetylcholine-induced vascular relaxation. These beneficial effects were associated with induction of mitochondrial complexes I and V, increased mitochondrial DNA copy number, and greater expression of transcription factors involved in mitochondrial biogenesis/fusion. We also observed enhanced mitochondrial autophagy pathway activity, including increased conversion of LC3-I to LC3-II and greater expression of beclin1 and autophagy-related protein-7 (ATG7). The levels of thiobarbituric acid-reactive substances and protein carbonyls remained unchanged, whereas significant increases in catalase and mitochondrial manganese superoxide dismutase (MnSOD) levels were observed in the aortas of trained animals, when compared with sedentary controls. Nandrolone increased oxidative stress biomarkers and inhibited exercise-induced increases of eNOS, HO-1, catalase, and MnSOD expression. In addition, it also attenuated elevated peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) and mitofusin-2 expression, and further up-regulated LC3II conversion, beclin1, ATG7, and dynamin-related protein-1 expression. These results demonstrate that nandrolone attenuates aortic adaptations to exercise by regulating mitochondrial dynamic remodelling, including down-regulation of mitochondrial biogenesis and intensive autophagy.

Evidence for cognitive-behavioral strategies improving dyspnea and related distress in COPD.

PubMed

Norweg, Anna; Collins, Eileen G

2013-01-01

Dyspnea is a complex, prevalent, and distressing symptom of chronic obstructive pulmonary disease (COPD) associated with decreased quality of life, significant disability, and increased mortality. It is a major reason for referral to pulmonary rehabilitation. We reviewed 23 COPD studies to examine the evidence for the effectiveness of cognitive-behavioral strategies for relieving dyspnea in COPD. Preliminary evidence from randomized controlled trials exists to support cognitive- behavioral strategies, used with or without exercise, for relieving sensory and affective components of dyspnea in COPD. Small to moderate treatment effects for relieving dyspnea were noted for psychotherapy (effect size [ES] = 0.08-0.25 for intensity; 0.26-0.65 for mastery) and distractive auditory stimuli (ES = 0.08-0.33 for intensity; 0.09 to -0.61 for functional burden). Small to large dyspnea improvements resulted from yoga (ES = 0.2-1.21 for intensity; 0.67 for distress; 0.07 for mastery; and -8.37 for functional burden); dyspnea self-management education with exercise (ES = -0.14 to -1.15 for intensity; -0.62 to -0.69 for distress; 1.04 for mastery; 0.14-0.35 for self-efficacy); and slow-breathing exercises (ES = -0.34 to -0.83 for intensity; -0.61 to -0.80 for distress; and 0.62 for self-efficacy). Cognitive-behavioral interventions may relieve dyspnea in COPD by (1) decreasing sympathetic nerve activity, dynamic hyperinflation, and comorbid anxiety, and (2) promoting arterial oxygen saturation, myelinated vagus nerve activity, a greater exercise training effect, and neuroplasticity. While evidence is increasing, additional randomized controlled trials are needed to evaluate the effectiveness of psychosocial and self-management interventions in relieving dyspnea, in order to make them more available to patients and to endorse them in official COPD, dyspnea, and pulmonary rehabilitation practice guidelines. By relieving dyspnea and related anxiety, such interventions may promote adherence to exercise programs and adaptive lifestyle change.

Associations of exercise-induced hormone profiles and gains in strength and hypertrophy in a large cohort after weight training.

PubMed

West, Daniel W D; Phillips, Stuart M

2012-07-01

The purpose of this study was to investigate associations between acute exercise-induced hormone responses and adaptations to high intensity resistance training in a large cohort (n = 56) of young men. Acute post-exercise serum growth hormone (GH), free testosterone (fT), insulin-like growth factor (IGF-1) and cortisol responses were determined following an acute intense leg resistance exercise routine at the midpoint of a 12-week resistance exercise training study. Acute hormonal responses were correlated with gains in lean body mass (LBM), muscle fibre cross-sectional area (CSA) and leg press strength. There were no significant correlations between the exercise-induced elevations (area under the curve-AUC) of GH, fT and IGF-1 and gains in LBM or leg press strength. Significant correlations were found for cortisol, usually assumed to be a hormone indicative of catabolic drive, AUC with change in LBM (r = 0.29, P < 0.05) and type II fibre CSA (r = 0.35, P < 0.01) as well as GH AUC and gain in fibre area (type I: r = 0.36, P = 0.006; type II: r = 0.28, P = 0.04, but not lean mass). No correlations with strength were observed. We report that the acute exercise-induced systemic hormonal responses of cortisol and GH are weakly correlated with resistance training-induced changes in fibre CSA and LBM (cortisol only), but not with changes in strength.

Effects of Spinal Cord Injury in Heart Rate Variability After Acute and Chronic Exercise: A Systematic Review.

PubMed

Buker, Daniel Bueno; Oyarce, Cristóbal Castillo; Plaza, Raúl Smith

2018-01-01

Background: Spinal cord injury (SCI) above T6 is followed by a loss of sympathetic supraspinal control of the heart, disturbing the autonomic balance and increasing cardiovascular risk. Heart rate variability (HRV) is a widely used tool for assessing the cardiac autonomic nervous system and positive adaptations after regular exercise in able-bodied subjects. However, adaptations in SCI subjects are not well known. Objectives: To compare HRV between able-bodied and SCI subjects and analyze the effects of chronic and acute exercise on HRV in the SCI group. Methods: We searched MEDLINE, Embase, Web of Science, SciELO, and Google Scholar databases to July 2016. We selected English and Spanish observational or experimental studies reporting HRV after training or acute exercise in SCI patients. We also included studies comparing HRV in SCI individuals with able-bodied subjects. Animal studies and nontraumatic SCI studies were excluded. We screened 279 articles by title and abstract; of these, we fully reviewed 29 articles. Eighteen articles fulfilled criteria for inclusion in this study. Results: SCI individuals showed lower HRV values in the low frequency band compared to able-bodied subjects. Regular exercise improved HRV in SCI subjects, however time and intensity data were lacking. HRV decreases after an acute bout of exercise on SCI subjects, but recovery kinetics are unknown. Conclusion: HRV is affected following SCI. Able-bodied subjects and SCI individuals have different values of HRV. Acute bouts of exercise change HRV temporarily, and chronic exercise might improve autonomic balance in SCI.

Rapid Communication: Dietary selenium improves skeletal muscle mitochondrial biogenesis in young equine athletes.

PubMed

White, S H; Wohlgemuth, S; Li, C; Warren, L K

2017-09-01

Exercise is known to promote mitochondrial biogenesis in skeletal muscle as well as enhance mitochondrial function and efficiency in human and rodent models. These adaptations help to decrease exercise-associated production of reactive oxygen species, which can negatively affect health and performance if antioxidant mechanisms are overwhelmed. Little is known about the adaptations of mitochondria in response to exercise training in the growing horse or if supplementation with a dietary antioxidant can improve mitochondrial function. To evaluate the separate and combined effects of selenium (Se) supplementation, training, and an acute strenuous exercise bout on mitochondrial adaptations in young horses, 30 American Quarter Horse yearlings were randomly assigned to an exercise training group or a no-training group and, within each group, received either 0.1 or 0.3 mg Se/kg DM for 14 wk. The study was split into 2 phases (wk 0 to 8 and wk 9 to 14), with half of the trained horses switched to the opposite dietary treatment in Phase 2. At the end of each phase, all horses underwent a 120-min submaximal exercise test (SET; SET 1 and SET 2). Biopsies of the middle gluteal muscle were collected before and after each phase of the study and in response to each SET and analyzed for markers of mitochondrial number and function. At rest, horses receiving 0.3 mg Se/kg DM had higher citrate synthase activity ( = 0.021) than horses receiving 0.1 mg Se/kg DM, indicating higher mitochondrial content. In contrast, cytochrome oxidase (CCO) activity was not affected by dietary Se overall, but horses that were dropped from 0.3 mg Se/kg DM to 0.1 mg Se/kg DM during Phase 2 showed a decrease ( = 0.034) in integrated CCO activity from wk 9 to 14, suggesting impaired mitochondrial function. Mitochondrial enzyme activities were unaffected by an acute, strenuous exercise bout (SET 1 and SET 2). Our relatively low-intensity exercise training protocol did not appear to induce functional mitochondrial adaptations. However, elevated dietary Se may impart beneficial effects on mitochondrial biogenesis during growth and training. A more strenuous exercise training protocol should be investigated to determine the potential benefits of elevated dietary Se for elite equine athletes.

Hyperventilation-induced hypocapnic alkalosis slows the adaptation of pulmonary O2 uptake during the transition to moderate-intensity exercise

PubMed Central

Chin, Lisa M K; Leigh, Ryan J; Heigenhauser, George J F; Rossiter, Harry B; Paterson, Donald H; Kowalchuk, John M

2007-01-01

The effect of voluntary hyperventilation-induced hypocapnic alkalosis (RALK) on pulmonary O2 uptake (V˙o2) kinetics and muscle deoxygenation was examined in young male adults (n = 8) during moderate-intensity exercise. Subjects performed five repetitions of a step-transition in work rate from 20 W cycling to a work rate corresponding to 90% of the estimated lactate threshold during control (CON; , ∼40 mmHg) and during hyperventilation (RALK; , ∼20 mmHg). V˙o2 was measured breath-by-breath and relative concentration changes in muscle deoxy- (ΔHHb), oxy- (ΔO2Hb) and total (ΔHbtot) haemoglobin were measured continuously using near-infrared (NIR) spectroscopy (Hamamatsu, NIRO 300). The time constant for the fundamental, phase 2, V˙o2 response (τV˙o2) was greater (P < 0.05) in RALK (48 ± 11 s) than CON (31 ± 9 s), while τHHb was similar between conditions (RALK, 12 ± 4 s; CON, 11 ± 4 s). The ΔHbtot was lower (P < 0.05) in RALK than CON, prior to (RALK, −3 ± 5 μmol l−1; CON, −1 ± 4 μmol l−1) and at the end (RALK, 1 ± 6 μmol l−1; CON, 5 ± 5 μmol l−1) of moderate-intensity exercise. Although slower adaptation of V˙o2 during RALK may be related to an attenuated activation of PDH (and other enzymes) and provision of oxidizable substrate to the mitochondria (i.e. metabolic inertia), the present findings also suggest a role for a reduction in local muscle perfusion and O2 delivery. PMID:17584832

Dose-response relationship of the cardiovascular adaptation to endurance training in healthy adults: how much training for what benefit?

PubMed

Iwasaki, Ken-Ichi; Zhang, Rong; Zuckerman, Julie H; Levine, Benjamin D

2003-10-01

Occupational or recreational exercise reduces mortality from cardiovascular disease. The potential mechanisms for this reduction may include changes in blood pressure (BP) and autonomic control of the circulation. Therefore, we conducted the present long-term longitudinal study to quantify the dose-response relationship between the volume and intensity of exercise training, and regulation of heart rate (HR) and BP. We measured steady-state hemodynamics and analyzed dynamic cardiovascular regulation by spectral and transfer function analysis of cardiovascular variability in 11 initially sedentary subjects during 1 yr of progressive endurance training sufficient to allow them to complete a marathon. From this, we found that 1) moderate exercise training for 3 mo decreased BP, HR, and total peripheral resistance, and increased cardiovascular variability and arterial baroreflex sensitivity; 2) more prolonged and intense training did not augment these changes further; and 3) most of these changes returned to control values at 12 mo despite markedly increased training duration and intensity equivalent to that routinely observed in competitive athletes. In conclusion, increases in R-wave-R-wave interval and cardiovascular variability indexes are consistent with an augmentation of vagal modulation of HR after exercise training. It appears that moderate doses of training for 3 mo are sufficient to achieve this response as well as a modest hypotensive effect from decreasing vascular resistance. However, more prolonged and intense training does not necessarily lead to greater enhancement of circulatory control and, therefore, may not provide an added protective benefit via autonomic mechanisms against death by cardiovascular disease.

Effects of circuit low-intensity resistance exercise with slow movement on oxygen consumption during and after exercise.

PubMed

Mukaimoto, Takahiro; Ohno, Makoto

2012-01-01

The purpose of this study was to examine oxygen consumption (VO(2)) during and after a single bout of low-intensity resistance exercise with slow movement. Eleven healthy men performed the following three types of circuit resistance exercise on separate days: (1) low-intensity resistance exercise with slow movement: 50% of one-repetition maximum (1-RM) and 4 s each of lifting and lowering phases; (2) high-intensity resistance exercise with normal movement: 80% of 1-RM and 1 s each of lifting and lowering phases; and (3) low-intensity resistance exercise with normal movement: 50% of 1-RM and 1 s each of lifting and lowering phases. These three resistance exercise trials were performed for three sets in a circuit pattern with four exercises, and the participants performed each set until exhaustion. Oxygen consumption was monitored continuously during exercise and for 180 min after exercise. Average VO(2) throughout the exercise session was significantly higher with high- and low-intensity resistance exercise with normal movement than with low-intensity resistance exercise with slow movement (P < 0.05); however, total VO(2) was significantly greater in low-intensity resistance exercise with slow movement than in the other trials. In contrast, there were no significant differences in the total excess post-exercise oxygen consumption among the three exercise trials. The results of this study suggest that low-intensity resistance exercise with slow movement induces much greater energy expenditure than resistance exercise with normal movement of high or low intensity, and is followed by the same total excess post-exercise oxygen consumption for 180 min after exercise.

Cardiac adaptations from 4 weeks of intensity-controlled vigorous exercise are lost after a similar period of detraining

PubMed Central

Waring, Cheryl D; Henning, Beverley J; Smith, Andrew J; Nadal-Ginard, Bernardo; Torella, Daniele; Ellison, Georgina M

2015-01-01

Intensity-controlled (relative to VO2max) treadmill exercise training in adult rats results in the activation and ensuing differentiation of endogenous c-kitpos cardiac stem/progenitor cells (eCSCs) into newly formed cardiomyocytes and capillaries. Whether these training-induced adaptations persist following detraining is undetermined. Twelve male Wistar rats (∼230 g) were exercised at 80–85% of their VO2max for 30 min day−1, 4 days week−1 for 4 weeks (TR;n = 6), followed by 4 weeks of detraining (DTR; n = 6). Twelve untrained rats acted as controls (CTRL). Exercise training significantly enhanced VO2max (11.34 mL kg−1 min−1) and wet heart weight (29%) above CTRL (P < 0.05). Echocardiography revealed that exercise training increased LV mass (∼32%), posterior and septal wall thickness (∼15%), ejection fraction and fractional shortening (∼10%) compared to CTRL (P < 0.05). Cardiomyocyte diameter (17.9 ± 0.1 μm vs. 14.9 ± 0.6 μm), newly formed (BrdUpos/Ki67pos) cardiomyocytes (7.2 ± 1.3%/1.9 ± 0.7% vs. 0.2 ± 0.1%/0.1 ± 0.1%), total cardiomyocyte number (45.6 ± 0.6 × 106 vs. 42.5 ± 0.4 × 106), c-kitpos eCSC number (884 ± 112 per 106 cardiomyocytes vs. 482 ± 132 per 106 cardiomyocytes), and capillary density (4123 ± 227 per mm2 vs. 2117 ± 118 per mm2) were significantly greater in the LV of trained animals (P < 0.05) than CTRL. Detraining removed the stimulus for c-kitpos eCSC activation (640 ± 98 per 106 cardiomyocytes) and resultant cardiomyocyte hyperplasia (0.4 ± 0.3% BrdUpos/0.2 ± 0.2% Ki67pos cardiomyocytes). Capillary density (3673 ± 374 per mm2) and total myocyte number (44.7 ± 0.5 × 106) remained elevated following detraining, but cardiomyocyte hypertrophy (15.0 ± 0.4 μm) was lost, resulting in a reduction of anatomical (wall thickness ∼4%; LV mass ∼10% and cardiac mass ∼8%, above CTRL) and functional (EF & FS ∼2% above CTRL) parameters gained through exercise training. These findings demonstrate that cardiac adaptations, produced by 4 weeks of intensity-controlled exercise training are lost after a similar period of detraining. PMID:25713328

Ryanodine receptor fragmentation and sarcoplasmic reticulum Ca2+ leak after one session of high-intensity interval exercise

PubMed Central

Place, Nicolas; Ivarsson, Niklas; Venckunas, Tomas; Neyroud, Daria; Brazaitis, Marius; Cheng, Arthur J.; Ochala, Julien; Kamandulis, Sigitas; Girard, Sebastien; Volungevičius, Gintautas; Paužas, Henrikas; Mekideche, Abdelhafid; Kayser, Bengt; Martinez-Redondo, Vicente; Bruton, Joseph; Truffert, Andre; Lanner, Johanna T.; Skurvydas, Albertas; Westerblad, Håkan

2015-01-01

High-intensity interval training (HIIT) is a time-efficient way of improving physical performance in healthy subjects and in patients with common chronic diseases, but less so in elite endurance athletes. The mechanisms underlying the effectiveness of HIIT are uncertain. Here, recreationally active human subjects performed highly demanding HIIT consisting of 30-s bouts of all-out cycling with 4-min rest in between bouts (≤3 min total exercise time). Skeletal muscle biopsies taken 24 h after the HIIT exercise showed an extensive fragmentation of the sarcoplasmic reticulum (SR) Ca2+ release channel, the ryanodine receptor type 1 (RyR1). The HIIT exercise also caused a prolonged force depression and triggered major changes in the expression of genes related to endurance exercise. Subsequent experiments on elite endurance athletes performing the same HIIT exercise showed no RyR1 fragmentation or prolonged changes in the expression of endurance-related genes. Finally, mechanistic experiments performed on isolated mouse muscles exposed to HIIT-mimicking stimulation showed reactive oxygen/nitrogen species (ROS)-dependent RyR1 fragmentation, calpain activation, increased SR Ca2+ leak at rest, and depressed force production due to impaired SR Ca2+ release upon stimulation. In conclusion, HIIT exercise induces a ROS-dependent RyR1 fragmentation in muscles of recreationally active subjects, and the resulting changes in muscle fiber Ca2+-handling trigger muscular adaptations. However, the same HIIT exercise does not cause RyR1 fragmentation in muscles of elite endurance athletes, which may explain why HIIT is less effective in this group. PMID:26575622

Ryanodine receptor fragmentation and sarcoplasmic reticulum Ca2+ leak after one session of high-intensity interval exercise.

PubMed

Place, Nicolas; Ivarsson, Niklas; Venckunas, Tomas; Neyroud, Daria; Brazaitis, Marius; Cheng, Arthur J; Ochala, Julien; Kamandulis, Sigitas; Girard, Sebastien; Volungevičius, Gintautas; Paužas, Henrikas; Mekideche, Abdelhafid; Kayser, Bengt; Martinez-Redondo, Vicente; Ruas, Jorge L; Bruton, Joseph; Truffert, Andre; Lanner, Johanna T; Skurvydas, Albertas; Westerblad, Håkan

2015-12-15

High-intensity interval training (HIIT) is a time-efficient way of improving physical performance in healthy subjects and in patients with common chronic diseases, but less so in elite endurance athletes. The mechanisms underlying the effectiveness of HIIT are uncertain. Here, recreationally active human subjects performed highly demanding HIIT consisting of 30-s bouts of all-out cycling with 4-min rest in between bouts (≤3 min total exercise time). Skeletal muscle biopsies taken 24 h after the HIIT exercise showed an extensive fragmentation of the sarcoplasmic reticulum (SR) Ca(2+) release channel, the ryanodine receptor type 1 (RyR1). The HIIT exercise also caused a prolonged force depression and triggered major changes in the expression of genes related to endurance exercise. Subsequent experiments on elite endurance athletes performing the same HIIT exercise showed no RyR1 fragmentation or prolonged changes in the expression of endurance-related genes. Finally, mechanistic experiments performed on isolated mouse muscles exposed to HIIT-mimicking stimulation showed reactive oxygen/nitrogen species (ROS)-dependent RyR1 fragmentation, calpain activation, increased SR Ca(2+) leak at rest, and depressed force production due to impaired SR Ca(2+) release upon stimulation. In conclusion, HIIT exercise induces a ROS-dependent RyR1 fragmentation in muscles of recreationally active subjects, and the resulting changes in muscle fiber Ca(2+)-handling trigger muscular adaptations. However, the same HIIT exercise does not cause RyR1 fragmentation in muscles of elite endurance athletes, which may explain why HIIT is less effective in this group.

Beneficial Autophagic Activities, Mitochondrial Function, and Metabolic Phenotype Adaptations Promoted by High-Intensity Interval Training in a Rat Model

PubMed Central

Li, Fang-Hui; Li, Tao; Ai, Jing-Yi; Sun, Lei; Min, Zhu; Duan, Rui; Zhu, Ling; Liu, Yan-ying; Liu, Timon Cheng-Yi

2018-01-01

The effects of high-intensity interval (HIIT) and moderate-intensity continuous training (MICT) on basal autophagy and mitochondrial function in cardiac and skeletal muscle and plasma metabolic phenotypes have not been clearly characterized. Here, we investigated how 10-weeks HIIT and MICT differentially modify basal autophagy and mitochondrial markers in cardiac and skeletal muscle and conducted an untargeted metabolomics study with proton nuclear magnetic resonance (1H NMR) spectroscopy and multivariate statistical analysis of plasma metabolic phenotypes. Male Sprague–Dawley rats were separated into three groups: sedentary control (SED), MICT, and HIIT. Rats underwent evaluation of exercise performance, including exercise tolerance and grip strength, and blood lactate levels were measured immediately after an incremental exercise test. Plasma samples were analyzed by 1H NMR. The expression of autophagy and mitochondrial markers and autophagic flux (LC3II/LC3-I ratio) in cardiac, rectus femoris, and soleus muscle were analyzed by western blotting. Time to exhaustion and grip strength increased significantly following HIIT compared with that in both SED and MICT groups. Compared with those in the SED group, blood lactate level, and the expression of SDH, COX-IV, and SIRT3 significantly increased in rectus femoris and soleus muscle of both HIIT and MICT groups. Meanwhile, SDH and COX-IV content of cardiac muscle and COX-IV and SIRT3 content of rectus femoris and soleus muscle increased significantly following HIIT compared with that following MICT. The expression of LC3-II, ATG-3, and Beclin-1 and LC3II/LC3-I ratio were significantly increased only in soleus and cardiac muscle following HIIT. These data indicate that HIIT was more effective for improving physical performance and facilitating cardiac and skeletal muscle adaptations that increase mitochondrial function and basal autophagic activities. Moreover, 1H NMR spectroscopy and multivariate statistical analysis identified 11 metabolites in plasma, among which fine significantly and similarly changed after both HIIT and MICT, while BCAAs isoleucine, leucine, and valine and glutamine were changed only after HIIT. Together, these data indicate distinct differences in specific metabolites and autophagy and mitochondrial markers following HIIT vs. MICT and highlight the value of metabolomic analysis in providing more detailed insight into the metabolic adaptations to exercise training. PMID:29875683

Beneficial Autophagic Activities, Mitochondrial Function, and Metabolic Phenotype Adaptations Promoted by High-Intensity Interval Training in a Rat Model.

PubMed

Li, Fang-Hui; Li, Tao; Ai, Jing-Yi; Sun, Lei; Min, Zhu; Duan, Rui; Zhu, Ling; Liu, Yan-Ying; Liu, Timon Cheng-Yi

2018-01-01

The effects of high-intensity interval (HIIT) and moderate-intensity continuous training (MICT) on basal autophagy and mitochondrial function in cardiac and skeletal muscle and plasma metabolic phenotypes have not been clearly characterized. Here, we investigated how 10-weeks HIIT and MICT differentially modify basal autophagy and mitochondrial markers in cardiac and skeletal muscle and conducted an untargeted metabolomics study with proton nuclear magnetic resonance ( 1 H NMR) spectroscopy and multivariate statistical analysis of plasma metabolic phenotypes. Male Sprague-Dawley rats were separated into three groups: sedentary control (SED), MICT, and HIIT. Rats underwent evaluation of exercise performance, including exercise tolerance and grip strength, and blood lactate levels were measured immediately after an incremental exercise test. Plasma samples were analyzed by 1 H NMR. The expression of autophagy and mitochondrial markers and autophagic flux (LC3II/LC3-I ratio) in cardiac, rectus femoris, and soleus muscle were analyzed by western blotting. Time to exhaustion and grip strength increased significantly following HIIT compared with that in both SED and MICT groups. Compared with those in the SED group, blood lactate level, and the expression of SDH, COX-IV, and SIRT3 significantly increased in rectus femoris and soleus muscle of both HIIT and MICT groups. Meanwhile, SDH and COX-IV content of cardiac muscle and COX-IV and SIRT3 content of rectus femoris and soleus muscle increased significantly following HIIT compared with that following MICT. The expression of LC3-II, ATG-3, and Beclin-1 and LC3II/LC3-I ratio were significantly increased only in soleus and cardiac muscle following HIIT. These data indicate that HIIT was more effective for improving physical performance and facilitating cardiac and skeletal muscle adaptations that increase mitochondrial function and basal autophagic activities. Moreover, 1 H NMR spectroscopy and multivariate statistical analysis identified 11 metabolites in plasma, among which fine significantly and similarly changed after both HIIT and MICT, while BCAAs isoleucine, leucine, and valine and glutamine were changed only after HIIT. Together, these data indicate distinct differences in specific metabolites and autophagy and mitochondrial markers following HIIT vs. MICT and highlight the value of metabolomic analysis in providing more detailed insight into the metabolic adaptations to exercise training.

Different types of exercise induce differential effects on neuronal adaptations and memory performance.

PubMed

Lin, Tzu-Wei; Chen, Shean-Jen; Huang, Tung-Yi; Chang, Chia-Yuan; Chuang, Jih-Ing; Wu, Fong-Sen; Kuo, Yu-Min; Jen, Chauying J

2012-01-01

Different exercise paradigms show differential effects on various forms of memory. We hypothesize that the differential effects of exercises on memory performance are caused by different neuroplasticity changes in relevant brain regions in response to different exercise trainings. We examined the effects of treadmill running (TR) and wheel running (WR) on the Pavlovian fear conditioning task that assesses learning and memory performance associated with the amygdala (cued conditioning) and both the amygdala and hippocampus (contextual conditioning). The skeletal muscle citrate synthase activity, an indicator of aerobic capacity, was elevated in rats received 4 w of TR, but not WR. While both TR and WR elevated the contextual conditional response, only TR facilitated the cued conditional response. Using a single-neuron labeling technique, we found that while both TR and MR enlarged the dendritic field and increased the spine density in hippocampal CA3 neurons, only TR showed these effects in basolateral amygdalar neurons. Moreover, both types of exercise upregulated synaptic proteins (i.e., TrkB and SNAP-25) in the hippocampus; however only TR showed similar effects in the amygdala. Injection of K252a, a TrkB kinase inhibitor, in the dorsal hippocampus or basolateral amygdala abolished the exercise-facilitated contextual or cued fear learning and memory performance, respectively, regardless of the types of exercise. In summary, our results supported that different types of exercise affect the performance of learning and memory via BDNF-TrkB signaling and neuroplasticity in specific brain regions. The brain region-specific neuronal adaptations are possibly induced by various levels of intensity/stress elicited by different types of exercise. Copyright © 2011 Elsevier Inc. All rights reserved.

What influences acceptability and engagement with a high intensity exercise programme for people with stroke? A qualitative descriptive study.

PubMed

Signal, Nada; McPherson, Kathryn; Lewis, Gwyn; Kayes, Nicola; Saywell, Nicola; Mudge, Suzie; Taylor, Denise

2016-10-14

Intensity refers to the amount of effort or rate of work undertaken during exercise. People receiving rehabilitation after stroke frequently do not reach the moderate to high intensity exercise recommended to maximise gains. To explore the factors that influence the acceptability of, and engagement with, a high intensity group-based exercise programme for people with stroke. This qualitative descriptive study included 14 people with stroke who had completed a 12-week, high intensity group-based exercise rehabilitation programme. Semi-structured interviews were used to explore the acceptability of high intensity exercise and the barriers and facilitators to engagement. Interviews were recorded, transcribed and analysed using qualitative content analysis. The participants found high intensity exercise rehabilitation acceptable despite describing the exercise intensity as hard and reporting post-exercise fatigue. Participants accepted the fatigue as a normal response to exercise, and it did not appear to negatively influence engagement. The ease with which an individual engaged in high intensity exercise rehabilitation appeared to be mediated by inter-related factors, including: seeing progress, sourcing motivation, working hard, the people involved and the fit with the person and their life. Participants directly related the intensity of their effort to the gains that they made. In this study, people with stroke viewed training at higher intensities as a facilitator, not a barrier, to engagement in exercise rehabilitation. The findings may challenge assumptions about the influence of exercise intensity on engagement.

5' adenosine monophosphate-activated protein kinase, metabolism and exercise.

PubMed

Aschenbach, William G; Sakamoto, Kei; Goodyear, Laurie J

2004-01-01

The 5' adenosine monophosphate-activated protein kinase (AMPK) is a member of a metabolite-sensing protein kinase family that functions as a metabolic 'fuel gauge' in skeletal muscle. AMPK is a ubiquitous heterotrimeric protein, consisting of an alpha catalytic, and beta and gamma regulatory subunits that exist in multiple isoforms and are all required for full enzymatic activity. During exercise, AMPK becomes activated in skeletal muscle in response to changes in cellular energy status (e.g. increased adenosine monophosphate [AMP]/adenosine triphosphate [ATP] and creatine/phosphocreatine ratios) in an intensity-dependent manner, and serves to inhibit ATP-consuming pathways, and activate pathways involved in carbohydrate and fatty-acid metabolism to restore ATP levels. Recent evidence shows that although AMPK plays this key metabolic role during acute bouts of exercise, it is also an important component of the adaptive response of skeletal muscles to endurance exercise training because of its ability to alter muscle fuel reserves and expression of several exercise-responsive genes. This review discusses the putative roles of AMPK in acute and chronic exercise responses, and suggests avenues for future AMPK research in exercise physiology and biochemistry.

Brain-derived neurotrophic factor as a regulator of systemic and brain energy metabolism and cardiovascular health

PubMed Central

Rothman, Sarah M; Griffioen, Kathleen J; Wan, Ruiqian; Mattson, Mark P

2012-01-01

Overweight sedentary individuals are at increased risk for cardiovascular disease, diabetes, and some neurological disorders. Beneficial effects of dietary energy restriction (DER) and exercise on brain structural plasticity and behaviors have been demonstrated in animal models of aging and acute (stroke and trauma) and chronic (Alzheimer's and Parkinson's diseases) neurological disorders. The findings described later, and evolutionary considerations, suggest brain-derived neurotrophic factor (BDNF) plays a critical role in the integration and optimization of behavioral and metabolic responses to environments with limited energy resources and intense competition. In particular, BDNF signaling mediates adaptive responses of the central, autonomic, and peripheral nervous systems from exercise and DER. In the hypothalamus, BDNF inhibits food intake and increases energy expenditure. By promoting synaptic plasticity and neurogenesis in the hippocampus, BDNF mediates exercise- and DER-induced improvements in cognitive function and neuroprotection. DER improves cardiovascular stress adaptation by a mechanism involving enhancement of brainstem cholinergic activity. Collectively, findings reviewed in this paper provide a rationale for targeting BDNF signaling for novel therapeutic interventions in a range of metabolic and neurological disorders. PMID:22548651

Aerobic exercise enhances neural correlates of motor skill learning.

PubMed

Singh, Amaya M; Neva, Jason L; Staines, W Richard

2016-03-15

Repetitive, in-phase bimanual motor training tasks can expand the excitable cortical area of the trained muscles. Recent evidence suggests that an acute bout of moderate-intensity aerobic exercise can enhance the induction of rapid motor plasticity at the motor hotspot. However, these changes have not been investigated throughout the entire cortical representation. Furthermore, it is unclear how exercise-induced changes in excitability may relate to motor performance. We investigated whether aerobic exercise could enhance the neural correlates of motor learning. We hypothesized that the combination of exercise and training would increase the excitable cortical area to a greater extent than either exercise or training alone, and that the addition of exercise would enhance performance on a motor training task. 25 young, healthy, right-handed individuals were recruited and divided into two groups and three experimental conditions. The exercise group performed exercise alone (EX) and exercise followed by training (EXTR) while the training group performed training alone (TR). The combination of exercise and training increased excitability within the cortical map of the trained muscle to a greater extent than training alone. However, there was no difference in performance between the two groups. These results indicate that exercise may enhance the cortical adaptations to motor skill learning. Copyright © 2015 Elsevier B.V. All rights reserved.

Design, Implementation, and Wide Pilot Deployment of FitForAll: An Easy to use Exergaming Platform Improving Physical Fitness and Life Quality of Senior Citizens.

PubMed

Konstantinidis, Evdokimos I; Billis, Antonis S; Mouzakidis, Christos A; Zilidou, Vasiliki I; Antoniou, Panagiotis E; Bamidis, Panagiotis D

2016-01-01

Many platforms have emerged as response to the call for technology supporting active and healthy aging. Key requirements for any such e-health systems and any subsequent business exploitation are tailor-made design and proper evaluation. This paper presents the design, implementation, wide deployment, and evaluation of the low cost, physical exercise, and gaming (exergaming) FitForAll (FFA) platform system usability, user adherence to exercise, and efficacy are explored. The design of FFA is tailored to elderly populations, distilling literature guidelines and recommendations. The FFA architecture introduces standard physical exercise protocols in exergaming software engineering, as well as, standard physical assessment tests for augmented adaptability through adjustable exercise intensity. This opens up the way to next generation exergaming software, which may be more automatically/smartly adaptive. 116 elderly users piloted FFA five times/week, during an eight-week controlled intervention. Usability evaluation was formally conducted (SUS, SUMI questionnaires). Control group consisted of a size-matched elderly group following cognitive training. Efficacy was assessed objectively through the senior fitness (Fullerton) test, and subjectively, through WHOQoL-BREF comparisons of pre-postintervention between groups. Adherence to schedule was measured by attendance logs. The global SUMI score was 68.33±5.85%, while SUS was 77.7. Good usability perception is reflected in relatively high adherence of 82% for a daily two months pilot schedule. Compared to control group, elderly using FFA improved significantly strength, flexibility, endurance, and balance while presenting a significant trend in quality of life improvements. This is the first elderly focused exergaming platform intensively evaluated with more than 100 participants. The use of formal tools makes the findings comparable to other studies and forms an elderly exergaming corpus.

Very Low Volume Sprint Interval Exercise Suppresses Subjective Appetite, Lowers Acylated Ghrelin, and Elevates GLP-1 in Overweight Individuals: A Pilot Study.

PubMed

Holliday, Adrian; Blannin, Andrew K

2017-04-05

High-intensity exercise has been shown to elicit a transient suppression of appetite and create a more anorexigenic profile of appetite-associated hormones. It is yet to be fully elucidated whether such a response is observed following very low-volume, intermittent exercise at supramaximal intensity in those who are overweight. Eight overweight individuals (BMI 27.7 ± 1.7 kg·m²) completed resting (REST) and exercise (EX) trials in a counterbalanced order. EX consisted of 4 × 30 s "flat-out" cycling on an ergometer (adapted Wingate test). Two hours post-exercise (or REST), participants were presented with an ad libitum meal. Subjective appetite measures and blood samples were obtained throughout. Subjective appetite, measured using VAS, was significantly lower immediately after exercise compared with REST (38.0 ± 28.5 mm vs. 75.1 ± 26.2 mm, p = 0.018, d = 1.09). This difference remained significant 30 min post-exercise. Acylated ghrelin concentration was suppressed in EX compared with REST immediately post-exercise (113.4 ± 43.0 pg·mL -1 vs. 189.2 ± 91.8 pg·mL -1 , p = 0.03, d = 1.07) and remained lower until the ad libitum test-meal. Area-under-the-curve for GLP-1 concentration was significantly greater for EX, versus REST. There was no difference in absolute ad libitum intake or relative energy intake. As little as 4 × 30 s of "flat-out" cycling was sufficient to elicit a transient suppression of appetite and an enduring suppression of plasma acylated ghrelin. Nonetheless, food intake 2-h post-exercise was unaffected.

Very Low Volume Sprint Interval Exercise Suppresses Subjective Appetite, Lowers Acylated Ghrelin, and Elevates GLP-1 in Overweight Individuals: A Pilot Study

PubMed Central

Holliday, Adrian; Blannin, Andrew K.

2017-01-01

High-intensity exercise has been shown to elicit a transient suppression of appetite and create a more anorexigenic profile of appetite-associated hormones. It is yet to be fully elucidated whether such a response is observed following very low-volume, intermittent exercise at supramaximal intensity in those who are overweight. Eight overweight individuals (BMI 27.7 ± 1.7 kg·m2) completed resting (REST) and exercise (EX) trials in a counterbalanced order. EX consisted of 4 × 30 s “flat-out” cycling on an ergometer (adapted Wingate test). Two hours post-exercise (or REST), participants were presented with an ad libitum meal. Subjective appetite measures and blood samples were obtained throughout. Subjective appetite, measured using VAS, was significantly lower immediately after exercise compared with REST (38.0 ± 28.5 mm vs. 75.1 ± 26.2 mm, p = 0.018, d = 1.09). This difference remained significant 30 min post-exercise. Acylated ghrelin concentration was suppressed in EX compared with REST immediately post-exercise (113.4 ± 43.0 pg·mL−1 vs. 189.2 ± 91.8 pg·mL−1, p = 0.03, d = 1.07) and remained lower until the ad libitum test-meal. Area-under-the-curve for GLP-1 concentration was significantly greater for EX, versus REST. There was no difference in absolute ad libitum intake or relative energy intake. As little as 4 × 30 s of “flat-out” cycling was sufficient to elicit a transient suppression of appetite and an enduring suppression of plasma acylated ghrelin. Nonetheless, food intake 2-h post-exercise was unaffected. PMID:28379172

Criterion-related validity of perceived exertion scales in healthy children: a systematic review and meta-analysis.

PubMed

Rodríguez, Iván; Zambrano, Lysien; Manterola, Carlos

2016-04-01

Physiological parameters used to measure exercise intensity are oxygen uptake and heart rate. However, perceived exertion (PE) is a scale that has also been frequently applied. The objective of this study is to establish the criterion-related validity of PE scales in children during an incremental exercise test. Seven electronic databases were used. Studies aimed at assessing criterion-related validity of PE scales in healthy children during an incremental exercise test were included. Correlation coefficients were transformed into z-values and assessed in a meta-analysis by means of a fixed effects model if I2 was below 50% or a random effects model, if it was above 50%. wenty-five articles that studied 1418 children (boys: 49.2%) met the inclusion criteria. Children's average age was 10.5 years old. Exercise modalities included bike, running and stepping exercises. The weighted correlation coefficient was 0.835 (95% confidence interval: 0.762-0.887) and 0.874 (95% confidence interval: 0.794-0.924) for heart rate and oxygen uptake as reference criteria. The production paradigm and scales that had not been adapted to children showed the lowest measurement performance (p < 0.05). Measuring PE could be valid in healthy children during an incremental exercise test. Child-specific rating scales showed a better performance than those that had not been adapted to this population. Further studies with better methodological quality should be conducted in order to confirm these results. Sociedad Argentina de Pediatría.

Acute effects of high- and low-intensity exercise bouts on leukocyte counts.

PubMed

Neves, Pedro Rogério Da Silva; Tenório, Thiago Ricardo Dos Santos; Lins, Tatiana Acioli; Muniz, Maria Tereza Cartaxo; Pithon-Curi, Tânia Cristina; Botero, João Paulo; Do Prado, Wagner Luiz

2015-06-01

It is widely accepted that physical exercise may bring about changes in the immune system. Even acute bouts of exercise can alter the number and function of leukocytes, but the degree of white blood cell trafficking depends on the intensity and duration of exercise. The aim of this study was to analyze the acute and short-term effects of exercise intensity on leukocyte counts and leukocyte subsets. Nine physically healthy, active young males (21.0 ± 1.9 years) underwent three experimental trials: high exercise intensity [80% peak oxygen consumption (VO 2peak )], low exercise intensity (40% VO 2peak ), and the control condition (no exercise). Blood samples were collected prior to exercise, immediately after exercise, and 2 hours after exercise. Two-way analysis of variance for repeated measures was used to evaluate differences between the trials and the time-points, and to compare times within trials. There was a greater increase in the leukocyte count after high-intensity exercise, compared to the control condition ( p  < 0.01) and low-intensity exercise ( p  < 0.01). This effect was still present 2 hours after passive recovery ( p  < 0.01). When the same participants were submitted to different exercise intensities, the acute and short-term effects of exercise on white blood cells were intensity-dependent immediately after exercise (i.e., lymphocytosis and monocytosis) and 2 hours after passive recovery (i.e., neutrophilia).

Evidence for β-adrenergic modulation of sweating during incremental exercise in habitually trained males.

PubMed

Amano, Tatsuro; Shitara, Yosuke; Fujii, Naoto; Inoue, Yoshimitsu; Kondo, Narihiko

2017-07-01

The aim of the present study was to determine the β-adrenergic contribution to sweating during incremental exercise in habitually trained males. Nine habitually trained and 11 untrained males performed incremental cycling until exhaustion (20 W/min). Bilateral forearm sweat rates (ventilated capsule) were measured at two skin sites that were transdermally administered via iontophoresis with either 1% propranolol (Propranolol, a nonselective β-adrenergic receptor antagonist) or saline (Control). The sweat rate was evaluated as a function of both relative (percentage of maximum workload) and absolute exercise intensities. The sweat rate at the Propranolol site was lower than the control during exercise at 80 (0.57 ± 0.21 and 0.45 ± 0.19 mg·cm -2 ·min -1 for Control and Propranolol, respectively) and 90% (0.74 ± 0.22 and 0.65 ± 0.17 mg·cm -2 ·min -1 , respectively) of maximum workload in trained males (all P < 0.05). By contrast, no between-site differences in sweat rates were observed in untrained counterparts (all P > 0.05). At the same absolute intensity, higher sweat rates on the control site were observed in trained males relative to the untrained during exercise at 160 (0.23 ± 0.20 and 0.04 ± 0.05 mg·cm -2 ·min -1 for trained and untrained, respectively) and 180 W (0.40 ± 0.20 and 0.13 ± 0.13 mg·cm -2 ·min -1 , respectively) (all P < 0.05), whereas this between-group difference was not observed at the Propranolol site (all P > 0.05). We show that the β-adrenergic mechanism does modulate sweating during exercise at a submaximal high relative intensity in habitually trained males. The β-adrenergic mechanism may in part contribute to the greater sweat production in habitually trained males than in untrained counterparts during exercise. NEW & NOTEWORTHY We demonstrated for the first time that the β-adrenergic mechanism does modulate sweating (i.e., β-adrenergic sweating) during exercise using a localized β-adrenoceptor blockade in humans in vivo. β-Adrenergic sweating was evident in habitually trained individuals during exercise at a submaximal high relative intensity (80-90% maximal work). This observation advances our understanding of human thermoregulation during exercise and of the mechanism that underlies sweat gland adaptation to habitual exercise training. Copyright © 2017 the American Physiological Society.

Characterisation of the Mechanical Loads and Metabolic Intensity of the CAPO Kids Exercise Intervention for Healthy Primary School Children

PubMed Central

Nogueira, Rossana C.; Weeks, Benjamin K.; Beck, Belinda R.

2015-01-01

Sedentarism is associated with obesity and other chronic diseases at all ages. Increasing physical activity with in-school interventions, focusing on energy expenditure and bone loading reduces risk of a number of costly chronic diseases. The aim of the current study was to characterise the metabolic and musculoskeletal load intensity of the recent successful CAPO Kids exercise intervention. Pre and early pubertal children (10.4 ± 0.5 years old) from the CAPO Kids trial wore an armband sensor to estimate energy expenditure during a 10-minute CAPO Kids session. Eleven participants performed manoeuvres from the session on a force platform to determine vertical ground reaction forces. In total, 28 boys and 20 girls had armband measures and 11 boys and girls undertook GRF testing. The energy expenditure associated with the 10-minute session was 39.7 ± 9.3 kcal, with an average of 4 kcal·min-1. The intensity of physical activity was ‘vigorous’ to ‘very vigorous’ for 34% of the session. Vertical ground reaction forces of the CAPO Kids manoeuvres ranged from 1.3 ± 0.2 BW (cartwheels) to 5.4 ± 2.3 BW (360° jump). CAPO Kids generates adequate load intensity to stimulate positive health adaptations in both metabolic and musculoskeletal systems of pre and early pubertal children. Key points Energy expenditure of a single bout of CAPO Kids yields 39.7±9.3 kcal and includes activities performed at a vigorous and very vigorous intensity. Mechanical loads associated with CAPO Kids surpass five times bodyweight and more than 140 bodyweights per second. CAPO Kids intervention represents a viable approach to stimulate musculoskeletal and metabolic adaptation in children. PMID:26336343

Characterisation of the Mechanical Loads and Metabolic Intensity of the CAPO Kids Exercise Intervention for Healthy Primary School Children.

PubMed

Nogueira, Rossana C; Weeks, Benjamin K; Beck, Belinda R

2015-09-01

Sedentarism is associated with obesity and other chronic diseases at all ages. Increasing physical activity with in-school interventions, focusing on energy expenditure and bone loading reduces risk of a number of costly chronic diseases. The aim of the current study was to characterise the metabolic and musculoskeletal load intensity of the recent successful CAPO Kids exercise intervention. Pre and early pubertal children (10.4 ± 0.5 years old) from the CAPO Kids trial wore an armband sensor to estimate energy expenditure during a 10-minute CAPO Kids session. Eleven participants performed manoeuvres from the session on a force platform to determine vertical ground reaction forces. In total, 28 boys and 20 girls had armband measures and 11 boys and girls undertook GRF testing. The energy expenditure associated with the 10-minute session was 39.7 ± 9.3 kcal, with an average of 4 kcal·min-1. The intensity of physical activity was 'vigorous' to 'very vigorous' for 34% of the session. Vertical ground reaction forces of the CAPO Kids manoeuvres ranged from 1.3 ± 0.2 BW (cartwheels) to 5.4 ± 2.3 BW (360° jump). CAPO Kids generates adequate load intensity to stimulate positive health adaptations in both metabolic and musculoskeletal systems of pre and early pubertal children. Key pointsEnergy expenditure of a single bout of CAPO Kids yields 39.7±9.3 kcal and includes activities performed at a vigorous and very vigorous intensity.Mechanical loads associated with CAPO Kids surpass five times bodyweight and more than 140 bodyweights per second.CAPO Kids intervention represents a viable approach to stimulate musculoskeletal and metabolic adaptation in children.

Exercise Training and Peripheral Arterial Disease

PubMed Central

Haas, Tara L.; Lloyd, Pamela G.; Yang, Hsiao-Tung; Terjung, Ronald L.

2013-01-01

Peripheral arterial disease (PAD) is a common vascular disease that reduces blood flow capacity to the legs of patients. PAD leads to exercise intolerance that can progress in severity to greatly limit mobility, and in advanced cases leads to frank ischemia with pain at rest. It is estimated that 12–15 million people in the United States are diagnosed with PAD, with a much larger population that is undiagnosed. The presence of PAD predicts a 50–1500% increase in morbidity and mortality, depending on severity. Treatment of patients with PAD is limited to modification of cardiovascular disease risk factors, pharmacological intervention, surgery, and exercise therapy. Extended exercise programs that involve walking ~5 times/wk, at a significant intensity that requires frequent rest periods, are most significant. Pre-clinical studies and virtually all clinical trials demonstrate the benefits of exercise therapy, including: improved walking tolerance, modified inflammatory/hemostatic markers, enhanced vasoresponsiveness, adaptations within the limb (angiogenesis, arteriogenesis, mitochondrial synthesis) that enhance oxygen delivery and metabolic responses, potentially delayed progression of the disease, enhanced quality of life indices, and extended longevity. A synthesis is provided as to how these adaptations can develop in the context of our current state of knowledge and events known to be orchestrated by exercise. The benefits are so compelling that exercise prescription should be an essential option presented to patients with PAD in the absence of contraindications. Obviously, selecting for a life style pattern, that includes enhanced physical activity prior to the advance of PAD limitations, is the most desirable and beneficial. PMID:23720270

Effects of plyometric training on maximal-intensity exercise and endurance in male and female soccer players.

PubMed

Ramírez-Campillo, Rodrigo; Vergara-Pedreros, Marcelo; Henríquez-Olguín, Carlos; Martínez-Salazar, Cristian; Alvarez, Cristian; Nakamura, Fábio Yuzo; De La Fuente, Carlos I; Caniuqueo, Alexis; Alonso-Martinez, Alicia M; Izquierdo, Mikel

2016-01-01

In a randomised controlled trial design, effects of 6 weeks of plyometric training on maximal-intensity exercise and endurance performance were compared in male and female soccer players. Young (age 21.1 ± 2.7 years) players with similar training load and competitive background were assigned to training (women, n = 19; men, n = 21) and control (women, n = 19; men, n = 21) groups. Players were evaluated for lower- and upper-body maximal-intensity exercise, 30 m sprint, change of direction speed and endurance performance before and after 6 weeks of training. After intervention, the control groups did not change, whereas both training groups improved jumps (effect size (ES) = 0.35-1.76), throwing (ES = 0.62-0.78), sprint (ES = 0.86-1.44), change of direction speed (ES = 0.46-0.85) and endurance performance (ES = 0.42-0.62). There were no differences in performance improvements between the plyometric training groups. Both plyometric groups improved more in all performance tests than the controls. The results suggest that adaptations to plyometric training do not differ between men and women.

Body temperature modulates the antioxidant and acute immune responses to exercise.

PubMed

Mestre-Alfaro, Antonia; Ferrer, Miguel D; Banquells, Montserrat; Riera, Joan; Drobnic, Franchek; Sureda, Antoni; Tur, Josep A; Pons, Antoni

2012-06-01

The aim of this study was to determine the effects of whole body heat in combination with exercise on the oxidative stress and acute phase immune response. Nine male endurance-trained athletes voluntarily performed two running bouts of 45 minutes at 75-80% of VO(2max) in a climatic chamber in two conditions: cold and hot humid environment. Leukocyte, neutrophil and basophil counts significantly rose after exercise in both environments; it was significantly greater in the hot environment. Lymphocyte and neutrophil antioxidant enzyme activities and carbonyl index significantly increased or decreased after exercise only in the hot environment, respectively. The lymphocytes expression of catalase, Hsp72 and CuZn-superoxide dismutase was increased in the hot environment and Sirt3 in the cold environment, mainly during recovery. In conclusion, the increased core body temperature results in the acute phase immune response associated to intense exercise and in the immune cell adaptations to counteract the oxidative stress situation.

Dose-response relationships between exercise intensity, cravings, and inhibitory control in methamphetamine dependence: An ERPs study.

PubMed

Wang, Dongshi; Zhou, Chenglin; Zhao, Min; Wu, Xueping; Chang, Yu-Kai

2016-04-01

The present study integrated behavioral and neuroelectric approaches for determining the dose-response relationships between exercise intensity and methamphetamine (MA) craving and between exercise intensity and inhibitory control in individuals with MA dependence. Ninety-two individuals with MA dependence were randomly assigned to an exercise group (light, moderate, or vigorous intensity) or to a reading control group. The participants then completed a craving self-report at four time points: before exercise, during exercise, immediately after exercise, and 50 min after exercise. Event-related potentials were also recorded while the participants completed a standard Go/NoGo task and an MA-related Go/NoGo task approximately 20 min after exercise cessation. The reduction in self-reported MA craving scores of the moderate and vigorous intensity groups was greater than that of the light intensity and control groups during acute exercise as well as immediately and 50 min following exercise termination. Additionally, an inverted-U-shaped relationship between exercise intensity and inhibitory control was generally observed for the behavioral and neuroelectric indices, with the moderate intensity group exhibiting shorter Go reaction times, increased NoGo accuracy, and larger NoGo-N2 amplitudes. Acute exercise may provide benefits for MA-associated craving and inhibitory control in MA-dependent individuals, as revealed by behavioral and neuroelectric measures. Moderate-intensity exercise may be associated with more positive effects, providing preliminary evidence for the establishment of an exercise prescription regarding intensity for MA dependence. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Physiological models to understand exercise fatigue and the adaptations that predict or enhance athletic performance.

PubMed

Noakes, T D

2000-06-01

A popular concept in the exercise sciences holds that fatigue develops during exercise of moderate to high intensity, when the capacity of the cardiorespiratory system to provide oxygen to the exercising muscles falls behind their demand inducing "anaerobic" metabolism. But this cardiovascular/anaerobic model is unsatisfactory because (i) a more rigorous analysis indicates that the first organ to be affected by anaerobiosis during maximal exercise would likely be the heart, not the skeletal muscles. This probability was fully appreciated by the pioneering exercise physiologists, A. V Hill, A. Bock and D. B. Dill, but has been systematically ignored by modern exercise physiologists; (ii) no study has yet definitely established the presence of either anaerobiosis, hypoxia or ischaemia in skeletal muscle during maximal exercise; (iii) the model is unable to explain why exercise terminates in a variety of conditions including prolonged exercise, exercise in the heat and at altitude, and in those with chronic diseases of the heart and lungs, without any evidence for skeletal muscle anaerobiosis, hypoxia or ischaemia, and before there is full activation of the total skeletal muscle mass, and (iv) cardiovascular and other measures believed to relate to skeletal muscle anaerobiosis, including the maximum oxygen consumption (VO2 max) and the "anaerobic threshold", are indifferent predictors of exercise capacity in athletes with similar abilities. This review considers four additional models that need to be considered when factors limiting either short duration, maximal or prolonged submaximal exercise are evaluated. These additional models are: (i) the energy supply/energy depletion model; (ii) the muscle power/muscle recruitment model; (iii) the biomechanical model and (iv) the psychological model. By reviewing features of these models, this review provides a broad overview of the physiological, metabolic and biomechanical factors that may limit exercise performance under different exercise conditions. A more complete understanding of fatigue during exercise, and the relevance of the adaptations that develop with training, requires that the potential relevance of each model to fatigue under different conditions of exercise must be considered.

Maternal Forced Swimming Reduces Cell Proliferation in the Postnatal Dentate Gyrus of Mouse Offspring

PubMed Central

Wasinski, Frederick; Estrela, Gabriel R.; Arakaki, Aline M.; Bader, Michael; Alenina, Natalia; Klempin, Friederike; Araújo, Ronaldo C.

2016-01-01

Physical exercise positively affects the metabolism and induces proliferation of precursor cells in the adult brain. Maternal exercise likewise provokes adaptations early in the offspring. Using a high-intensity swimming protocol that comprises forced swim training before and during pregnancy, we determined the effect of maternal swimming on the mouse offspring's neurogenesis. Our data demonstrate decreased proliferation in sublayers of the postnatal dentate gyrus in offspring of swimming mother at postnatal day (P) 8 accompanied with decreased survival of newly generated cells 4 weeks later. The reduction in cell numbers was predominantly seen in the hilus and molecular layer. At P35, the reduced amount of cells was also reflected by a decrease in the population of newly generated immature and mature neurons of the granule cell layer. Our data suggest that forced maternal swimming at high-intensity has a negative effect on the neurogenic niche development in postnatal offspring. PMID:27621701

Carbohydrate feeding during recovery alters the skeletal muscle metabolic response to repeated sessions of high-intensity interval exercise in humans.

PubMed

Cochran, Andrew J R; Little, Jonathan P; Tarnopolsky, Mark A; Gibala, Martin J

2010-03-01

Exercise training under conditions of reduced carbohydrate (CHO) availability has been reported to augment gains in skeletal muscle oxidative capacity; however, the underlying mechanisms are unclear. We examined the effect of manipulating CHO intake on the acute metabolic response to high-intensity interval exercise, including signaling cascades linked to mitochondrial biogenesis. Ten men performed two trials in random order separated by >or=1 wk. Each trial consisted of a morning (AM) and afternoon (PM) training session (5 x 4 min cycling at approximately 90-95% of heart rate reserve) separated by 3 h of recovery during which subjects ingested a high-CHO drink (HI-HI) or nonenergetic placebo (HI-LO) before PM exercise. Biopsies (vastus lateralis) revealed that muscle phosphocreatine and ATP content were similar after AM exercise but decreased to a greater extent during PM exercise in HI-LO vs. HI-HI. Phosphorylation of p38 mitogen-activated protein kinase (MAPK) and AMP-activated protein kinase (AMPK) increased approximately 4-fold and 2-fold, respectively, during AM exercise with no difference between conditions. After PM exercise, p38 MAPK phosphorylation was higher in HI-LO vs. HI-HI, whereas AMPK was not different between conditions. Peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1 alpha) gene expression increased approximately 8-fold during recovery from AM exercise and remained elevated during PM exercise with no differences between conditions. Cytochrome oxidase subunit 4 (COXIV) mRNA was also elevated 3 h after AM exercise, with no difference between conditions. These data provide evidence that p38 MAPK is a nutrient-sensitive signaling molecule that could be involved in the altered skeletal muscle adaptive response reported after exercise training under conditions of restricted CHO intake, but further research is required to confirm this hypothesis.

Dietary Supplements for Health, Adaptation, and Recovery in Athletes.

PubMed

Rawson, Eric S; Miles, Mary P; Larson-Meyer, D Enette

2018-03-01

Some dietary supplements are recommended to athletes based on data that supports improved exercise performance. Other dietary supplements are not ergogenic per se, but may improve health, adaptation to exercise, or recovery from injury, and so could help athletes to train and/or compete more effectively. In this review, we describe several dietary supplements that may improve health, exercise adaptation, or recovery. Creatine monohydrate may improve recovery from and adaptation to intense training, recovery from periods of injury with extreme inactivity, cognitive processing, and reduce severity of or enhance recovery from mild traumatic brain injury (mTBI). Omega 3-fatty acid supplementation may also reduce severity of or enhance recovery from mTBI. Replenishment of vitamin D insufficiency or deficiency will likely improve some aspects of immune, bone, and muscle health. Probiotic supplementation can reduce the incidence, duration, and severity of upper respiratory tract infection, which may indirectly improve training or competitive performance. Preliminary data show that gelatin and/or collagen may improve connective tissue health. Some anti-inflammatory supplements, such as curcumin or tart cherry juice, may reduce inflammation and possibly delayed onset muscle soreness (DOMS). Beta-hydroxy beta-methylbutyrate (HMB) does not consistently increase strength and/or lean mass or reduce markers of muscle damage, but more research on recovery from injury that includes periods of extreme inactivity is needed. Several dietary supplements, including creatine monohydrate, omega 3-fatty acids, vitamin D, probiotics, gelatin, and curcumin/tart cherry juice could help athletes train and/or compete more effectively.

Endurance exercise intensity determination in the rehabilitation of coronary artery disease patients: a critical re-appraisal of current evidence.

PubMed

Hansen, Dominique; Stevens, An; Eijnde, Bert O; Dendale, Paul

2012-01-01

In the care of coronary artery disease (CAD) patients, the benefits of exercise therapy are generally established. Even though the selected endurance exercise intensity might affect medical safety, therapy adherence and effectiveness in the rehabilitation of CAD patients in how to determine endurance exercise intensity properly remains difficult. The aim of this review is to describe the available methods for endurance exercise intensity determination in the rehabilitation of CAD patients, accompanied with their (dis)advantages, validity and reproducibility. In general, endurance exercise intensity can objectively be determined in CAD patients by calculating a fraction of maximal exercise tolerance and/or determining ventilatory threshold after execution of a cardiopulmonary exercise test with ergospirometry. This can be translated to a corresponding training heart rate (HR) or workload. In the absence of ergospirometry equipment, target exercise HR can be calculated directly by different ways (fraction of maximal HR and/or Karvonen formula), and/or anaerobic threshold can be determined. However, the use of HR for determining exercise intensity during training sessions seems complicated, because many factors/conditions affect the HR. In this regard, proper standardization of the exercise sessions, as well as exercise testing, might be required to improve the accuracy of exercise intensity determination. Alternatively, subjective methods for the determination of endurance exercise intensity in CAD patients, such as the Borg ratings of perceived exertion and the talk test, have been developed. However, these methods lack proper validity and reliability to determine endurance exercise intensity in CAD patients. In conclusion, a practical and systematic approach for the determination of endurance exercise intensity in CAD patients is presented in this article.

Intestinal adaptations to a combination of different diets with and without endurance exercise.

PubMed

Daniels, Janice L; Bloomer, Richard J; van der Merwe, Marie; Davis, Samantha L; Buddington, Karyl K; Buddington, Randal K

2016-01-01

Endurance athletes search for diet regimens that will improve performance and decrease gastrointestinal disturbances during training and events. Although the intestine can adapt to changes in the amount and composition of dietary inputs, the responses to the combination of endurance exercise and diet are poorly understood. We evaluated small intestinal dimensions and mucosal architecture and calculated the capacities of the entire small intestine to digest maltose and maltodextrin and absorb glucose in response to two different diet types; a western human diet and the Daniel Fast, a vegan style diet, and with moderate intensity endurance training or a no-exercise sedentary lifestyle for a 13 week period (n = 7 per group). The influences of diet and exercise, alone and in combination, were analyzed by analysis of variation. Rats fed the western diet gained more weight (P < 0.05) due to more fat mass (P < 0.05), with a similar response for the sedentary compared with the exercised rats in each diet group (P < 0.05). The Daniel Fast rats had longer and heavier intestines with deeper crypts with villi that were wider (P < 0.05), but not taller. Despite increased energetic demands, the exercised rats had shorter and lighter intestines with shorter villi (P < 0.05). Yet, the percentage of mucosa did not differ among groups. Total small intestinal activities for maltase and α-glucoamylase, and capacities for glucose absorption were similar regardless of diet or exercise. These findings indicate the structural responses of the small intestine to a vegan style diet are modified by exercise, but without altering the capacities of the brush border membrane to digest and absorb carbohydrates.

Combining remote ischemic preconditioning and aerobic exercise: a novel adaptation of blood flow restriction exercise.

PubMed

Sprick, Justin D; Rickards, Caroline A

2017-11-01

Remote ischemic preconditioning (RIPC) can attenuate tissue damage sustained by ischemia-reperfusion injury. Blood flow restriction exercise (BFRE) restricts blood flow to exercising muscles. We implemented a novel approach to BFRE with cyclical bouts of blood flow restriction-reperfusion, reflecting the RIPC model. A concern about BFRE, however, is potential amplification of the exercise pressor reflex, which could be unsafe in at-risk populations. We hypothesized that cyclical BFRE would elicit greater increases in sympathetic outflow and arterial pressure than conventional exercise (CE) when performed at the same relative intensity. We also assessed the cerebrovascular responses due to potential implementation of BFRE in stroke rehabilitation. Fourteen subjects performed treadmill exercise at 65-70% maximal heart rate with and without intermittent BFR (4 × 5-min intervals of bilateral thigh-cuff pressure followed by 5-min reperfusion periods). Mean arterial pressure (MAP), plasma norepinephrine (NE), and middle and posterior cerebral artery velocities (MCAv and PCAv) were compared between trials. As expected, BFRE elicited higher concentration NE compared with CE (1249 ± 170 vs. 962 ± 114 pg/ml; P = 0.06). Unexpectedly, however, there were no differences in MAP between conditions (overall P = 0.33), and MAP was 4-5 mmHg lower with BFRE versus CE during the reperfusion periods ( P ≤ 0.05 for reperfusion periods 3 and 4 ). There were no differences in MCAv or PCAv between trials ( P ≥ 0.22), suggesting equivalent cerebrometabolic demand. The exaggerated sympathoexcitatory response with BFRE was not accompanied by higher MAP, likely because of the cyclical reperfusions. This cyclical BFRE paradigm could be adapted to cardiac or stroke rehabilitation, where exercising patients could benefit from the cardio and cerebro protection associated with RIPC. Copyright © 2017 the American Physiological Society.

Oscillation of tissue oxygen index in non-exercising muscle during exercise.

PubMed

Yano, T; Afroundeh, R; Shirakawa, K; Lian, C-S; Shibata, K; Xiao, Z; Yunoki, T

2015-09-01

The purpose of the present study was to examine how oscillation of tissue oxygen index (TOI) in non-exercising exercise is affected during high-intensity and low-intensity exercises. Three exercises were performed with exercise intensities of 30% and 70% peak oxygen uptake (Vo(2)peak) for 12 min and with exercise intensity of 70% Vo(2)peak for 30 s. TOI in non-exercising muscle (biceps brachii) during the exercises for 12 min was determined by nearinfrared spectroscopy. TOI in the non-exercising muscle during the exercises was analyzed by fast Fourier transform (FFT) to obtain power spectra density (PSD). The frequency at which maximal PSD appeared (Fmax) during the exercise with 70% Vo(2)peak for 12 min (0.00477 ± 0.00172 Hz) was significantly lower than that during the exercise with 30% Vo2peak for 12 min (0.00781 ± 0.00338 Hz). There were significant differences in blood pH and blood lactate between the exercise with 70% Vo(2)peak and the exercise with 30% Vo(2)peak. It is concluded that TOI in nonexercising muscle oscillates during low-intensity exercise as well as during high-intensity exercise and that the difference in Fmax between the two exercises is associated with the difference in increase in blood lactate derived from the exercise.

Multicomponent Exercise Improves Hemodynamic Parameters and Mobility, but Not Maximal Walking Speed, Transfer Capacity, and Executive Function of Older Type II Diabetic Patients.

PubMed

Coelho Junior, Hélio José; Callado Sanches, Iris; Doro, Marcio; Asano, Ricardo Yukio; Feriani, Daniele Jardim; Brietzke, Cayque; Gonçalves, Ivan de Oliveira; Uchida, Marco Carlos; Capeturo, Erico Chagas; Rodrigues, Bruno

2018-01-01

The present study aimed to investigate the effects of a 6-month multicomponent exercise program (MCEP) on functional, cognitive, and hemodynamic parameters of older Type 2 diabetes mellitus (T2DM) patients. Moreover, additional analyses were performed to evaluate if T2DM patients present impaired adaptability in response to physical exercise when compared to nondiabetic volunteers. A total of 72 T2DM patients and 72 age-matched healthy volunteers (CG) were recruited and submitted to functional, cognitive, and hemodynamic evaluations before and after six months of a MCEP. The program of exercise was performed twice a week at moderate intensity. Results indicate T2DM and nondiabetic patients present an increase in mobility (i.e., usual walking speed) after the MCEP. However, improvements in maximal walking speed, transfer capacity, and executive function were only observed in the CG. On the other hand, only T2DM group reveals a marked decline in blood pressure. In conclusion, data of the current study indicate that a 6-month MCEP improves mobility and reduce blood pressure in T2DM patients. However, maximal walking speed, transfer capacity, and executive function were only improved in CG, indicating that T2DM may present impaired adaptability in response to physical stimulus.

Exercise intensity-dependent changes in the inflammatory response in sedentary women: role of neuroendocrine parameters in the neutrophil phagocytic process and the pro-/anti-inflammatory cytokine balance.

PubMed

Giraldo, E; Garcia, J J; Hinchado, M D; Ortega, E

2009-01-01

It is still not really known what is the optimal level of exercise that improves, but does not impair or overstimulate the innate immune function. This is especially the case in women, who have higher basal levels of 'inflammatory markers' than men. The aim of this work was to evaluate differences in the magnitude of the stimulation of the innate/inflammatory response following a single bout of moderate or intense exercise in sedentary women, all of them in the follicular phase of their menstrual cycle. Changes in stress and sexual hormones were also evaluated. Changes induced by exercise (45 min at 55% VO(2) max vs. 1 h at 70% VO(2) max on a cycle ergometer) in the phagocytic process (chemotaxis, phagocytosis, and microbicide capacity against Candida albicans) and in serum concentrations of IL-1beta, IL-2, IFN-gamma, IL-12, IL-6, and IL-4 (ELISA) were evaluated. Parallel determinations were also made of serum or plasma concentrations of catecholamines (HPLC) and cortisol, oestradiol, and progesterone (electrochemiluminescence immunoassay). Both exercise intensities increased chemotaxis, phagocytosis, and microbicide capacity of the neutrophils. However, the increase in chemotaxis was greater after moderate exercise. All the cytokines assayed were affected by exercise intensity. IFN-gamma increased significantly only immediately after the intense exercise; IL-1beta increased following both exercise intensities, although at 24 h it only remained elevated after the intense exercise; IL-12 only increased 24 h after the intense exercise, and IL-2 only showed a significant decrease following the moderate exercise. IL-6 increased immediately after both exercise intensities, but more so after moderate exercise. While IL-4 (an anti-inflammatory cytokine) increased following the moderate exercise, it decreased after the intense exercise. Both moderate and intense exercise increased norepinephrine and decreased cortisol, both of which returned to basal levels after 24 h. Only the intense exercise affected the epinephrine, oestradiol, and progesterone concentrations, with increases in epinephrine and oestradiol immediately after exercise, and a decrease in progesterone after 24 h. Both moderate and intense exercise stimulate the phagocytic process of neutrophils in sedentary women, but the profile of pro-/anti-inflammatory cytokine release seems to be better following the moderate exercise. The possible participation of stress (catecholamines and cortisol) and sex (oestradiol and progesterone) hormones in these intensity-dependent immune changes is discussed. Copyright 2009 S. Karger AG, Basel.

Atrial Fibrillation in Endurance Athletes: From Mechanism to Management.

PubMed

Elliott, Adrian D; Mahajan, Rajiv; Lau, Dennis H; Sanders, Prashanthan

2016-11-01

Exercise training has considerable health benefits. However, recent research has demonstrated a greater risk of atrial arrhythmias in endurance athletes. The mechanisms promoting atrial fibrillation in athletes are unclear but there seems to be a central role for atrial remodeling, accompanied by autonomic alterations and inflammation. Animal studies have provided unique insights, yet prospective human data are lacking. Treatment options seem to yield similar efficacy to that seen in a nonathletic population and may be justified as an early rhythm control strategy. Further studies are required to enhance understanding of the cardiac adaptations to intensive exercise training. Copyright © 2016 Elsevier Inc. All rights reserved.

Muscle Adaptations Following Short-Duration Bed Rest with Integrated Resistance, Interval, and Aerobic Exercise

NASA Technical Reports Server (NTRS)

Hackney, Kyle J.; Scott, Jessica M.; Buxton, Roxanne; Redd-Goetchius, Elizabeth; Crowell, J. Brent; Everett, Meghan E.; Wickwire, Jason; Ryder, Jeffrey W.; Bloomberg, Jacob J.; Ploutz-Snyder, Lori L.

2011-01-01

Unloading of the musculoskeletal system during space flight results in deconditioning that may impair mission-related task performance in astronauts. Exercise countermeasures have been frequently tested during bed rest (BR) and limb suspension; however, high-intensity, short-duration exercise prescriptions have not been fully explored. PURPOSE: To determine if a high intensity resistance, interval, and aerobic exercise program could protect against muscle atrophy and dysfunction when performed during short duration BR. METHODS: Nine subjects (1 female, 8 male) performed a combination of supine exercises during 2 weeks of horizontal BR. Resistance exercise (3 d / wk) consisted of squat, leg press, hamstring curl, and heel raise exercises (3 sets, 12 repetitions). Aerobic (6 d / wk) sessions alternated continuous (75% VO2 peak) and interval exercise (30 s, 2 min, and 4 min) and were completed on a supine cycle ergometer and vertical treadmill, respectively. Muscle volumes of the upper leg were calculated pre, mid, and post-BR using magnetic resonance imaging. Maximal isometric force (MIF), rate of force development (RFD), and peak power of the lower body extensors were measured twice before BR (averaged to represent pre) and once post BR. ANOVA with repeated measures and a priori planned contrasts were used to test for differences. RESULTS: There were no changes to quadriceps, hamstring, and adductor muscle volumes at mid and post BR time points compared to pre BR (Table 1). Peak power increased significantly from 1614 +/- 372 W to 1739 +/- 359 W post BR (+7.7%, p = 0.035). Neither MIF (pre: 1676 +/- 320 N vs. post: 1711 +/- 250 N, +2.1%, p = 0.333) nor RFD (pre: 7534 +/- 1265 N/ms vs. post: 6951 +/- 1241 N/ms, -7.7%, p = 0.136) were significantly impaired post BR.

Active Recovery After High-Intensity Interval-Training Does Not Attenuate Training Adaptation.

PubMed

Wiewelhove, Thimo; Schneider, Christoph; Schmidt, Alina; Döweling, Alexander; Meyer, Tim; Kellmann, Michael; Pfeiffer, Mark; Ferrauti, Alexander

2018-01-01

Objective: High-intensity interval training (HIIT) can be extremely demanding and can consequently produce high blood lactate levels. Previous studies have shown that lactate is a potent metabolic stimulus, which is important for adaptation. Active recovery (ACT) after intensive exercise, however, enhances blood lactate removal in comparison with passive recovery (PAS) and, consequently, may attenuate endurance performance improvements. Therefore, the aim of this study was to examine the influence of regular ACT on training adaptations during a HIIT mesocycle. Methods: Twenty-six well-trained male intermittent sport athletes (age: 23.5 ± 2.5 years; O 2 max: 55.36 ± 3.69 ml min kg -1 ) participated in a randomized controlled trial consisting of 4 weeks of a running-based HIIT mesocycle with a total of 12 HIIT sessions. After each training session, participants completed 15 min of either moderate jogging (ACT) or PAS. Subjects were matched to the ACT or PAS groups according to age and performance. Before the HIIT program and 1 week after the last training session, the athletes performed a progressive incremental exercise test on a motor-driven treadmill to determine O 2 max, maximum running velocity (vmax), the running velocity at which O 2 max occurs (vO 2 max), and anaerobic lactate threshold (AT). Furthermore, repeated sprint ability (RSA) were determined. Results: In the whole group the HIIT mesocycle induced significant or small to moderate changes in vmax ( p < 0.001, effect size [ES] = 0.65,), vO 2 max ( p < 0.001, ES = 0.62), and AT ( p < 0.001, ES = 0.56) compared with the values before the intervention. O 2 max and RSA remained unchanged throughout the study. In addition, no significant differences in the changes were noted in any of the parameters between ACT and PAS except for AT ( p < 0.05, ES = 0.57). Conclusion: Regular use of individualized ACT did not attenuate training adaptations during a HIIT mesocycle compared to PAS. Interestingly, we found that the ACT group obtained a significantly higher AT following the training program compared to the PAS group. This could be because ACT allows a continuation of the training at a low intensity and may activate specific adaptive mechanisms that are not triggered during PAS.

Active Recovery After High-Intensity Interval-Training Does Not Attenuate Training Adaptation

PubMed Central

Wiewelhove, Thimo; Schneider, Christoph; Schmidt, Alina; Döweling, Alexander; Meyer, Tim; Kellmann, Michael; Pfeiffer, Mark; Ferrauti, Alexander

2018-01-01

Objective: High-intensity interval training (HIIT) can be extremely demanding and can consequently produce high blood lactate levels. Previous studies have shown that lactate is a potent metabolic stimulus, which is important for adaptation. Active recovery (ACT) after intensive exercise, however, enhances blood lactate removal in comparison with passive recovery (PAS) and, consequently, may attenuate endurance performance improvements. Therefore, the aim of this study was to examine the influence of regular ACT on training adaptations during a HIIT mesocycle. Methods: Twenty-six well-trained male intermittent sport athletes (age: 23.5 ± 2.5 years; O2max: 55.36 ± 3.69 ml min kg-1) participated in a randomized controlled trial consisting of 4 weeks of a running-based HIIT mesocycle with a total of 12 HIIT sessions. After each training session, participants completed 15 min of either moderate jogging (ACT) or PAS. Subjects were matched to the ACT or PAS groups according to age and performance. Before the HIIT program and 1 week after the last training session, the athletes performed a progressive incremental exercise test on a motor-driven treadmill to determine O2max, maximum running velocity (vmax), the running velocity at which O2max occurs (vO2max), and anaerobic lactate threshold (AT). Furthermore, repeated sprint ability (RSA) were determined. Results: In the whole group the HIIT mesocycle induced significant or small to moderate changes in vmax (p < 0.001, effect size [ES] = 0.65,), vO2max (p < 0.001, ES = 0.62), and AT (p < 0.001, ES = 0.56) compared with the values before the intervention. O2max and RSA remained unchanged throughout the study. In addition, no significant differences in the changes were noted in any of the parameters between ACT and PAS except for AT (p < 0.05, ES = 0.57). Conclusion: Regular use of individualized ACT did not attenuate training adaptations during a HIIT mesocycle compared to PAS. Interestingly, we found that the ACT group obtained a significantly higher AT following the training program compared to the PAS group. This could be because ACT allows a continuation of the training at a low intensity and may activate specific adaptive mechanisms that are not triggered during PAS. PMID:29720949

Weight-loss and exercise for communities with arthritis in North Carolina (we-can): design and rationale of a pragmatic, assessor-blinded, randomized controlled trial.

PubMed

Messier, Stephen P; Callahan, Leigh F; Beavers, Daniel P; Queen, Kate; Mihalko, Shannon L; Miller, Gary D; Losina, Elena; Katz, Jeffrey N; Loeser, Richard F; Quandt, Sara A; DeVita, Paul; Hunter, David J; Lyles, Mary F; Newman, Jovita; Hackney, Betsy; Jordan, Joanne M

2017-02-22

Recently, we determined that in a rigorously monitored environment an intensive diet-induced weight loss of 10% combined with exercise was significantly more effective at reducing pain in men and women with symptomatic knee osteoarthritis (OA) than either intervention alone. Compared to previous long-term weight loss and exercise trials of knee OA, our intensive diet-induced weight loss and exercise intervention was twice as effective at reducing pain intensity. Whether these results can be generalized to less intensively monitored cohorts is unknown. Thus, the policy relevant and clinically important question is: Can we adapt this successful solution to a pervasive public health problem in real-world clinical and community settings? This study aims to develop a systematic, practical, cost-effective diet-induced weight loss and exercise intervention implemented in community settings and to determine its effectiveness in reducing pain and improving other clinical outcomes in persons with knee OA. This is a Phase III, pragmatic, assessor-blinded, randomized controlled trial. Participants will include 820 ambulatory, community-dwelling, overweight and obese (BMI ≥ 27 kg/m 2 ) men and women aged ≥ 50 years who meet the American College of Rheumatology clinical criteria for knee OA. The primary aim is to determine whether a community-based 18-month diet-induced weight loss and exercise intervention based on social cognitive theory and implemented in three North Carolina counties with diverse residential (from urban to rural) and socioeconomic composition significantly decreases knee pain in overweight and obese adults with knee OA relative to a nutrition and health attention control group. Secondary aims will determine whether this intervention improves self-reported function, health-related quality of life, mobility, and is cost-effective. Many physicians who treat people with knee OA have no practical means to implement weight loss and exercise treatments as recommended by numerous OA treatment guidelines. This study will establish the effectiveness of a community program that will serve as a blueprint and exemplar for clinicians and public health officials in urban and rural communities to implement a diet-induced weight loss and exercise program designed to reduce knee pain and improve other clinical outcomes in overweight and obese adults with knee OA. clinicaltrials.gov Identifier: NCT02577549 October 12, 2015.

Versatility of `hemorheologic fitness' according to exercise intensity: emphasis on the "healthy primitive lifestyle"

NASA Astrophysics Data System (ADS)

Brun, Jean-Frédéric; Varlet-Marie, Emmanuelle; Chevance, Guillaume; Pollatz, Marion; Fedou, Christine; de Mauverger, Eric Raynaud

2014-05-01

We recently proposed a unifying hypothesis to reconcile unexpected findings in exercise hemorheology and the classical concepts of "hemorheologic fitness" and the "triphasic effects of exercise", based on the "healthy primitive lifestyle" paradigm. This paradigm assumes that evolution has selected genetic polymorphisms leading to insulin resistance as an adaptative strategy to cope with continuous low intensity physical activity and a special alimentation moderately high in protein, rich in low glycemic index carbohydrates, and poor in saturated fat. According to this protocol the true physiological picture would be that of an individual whose exercise and nutritional habits are close from this lifestyle, both sedentary subjects and trained athletes representing situations on the edge of this model. Unfortunately samples of people truly adhering to this ancestral lifestyle are hard to obtain. In order to address this picture we tried to compare databases obtained with our preceding published studies. As a model of the "healthy primitive lifestyle" we selected patients trained at low intensity (LI) and given an advice of protein intake around 1.2 g/kg/day. Results show a continuum for plasma viscosity which seems to be lower in athletes than LI-trained and even more sedentaries. When sedentary subjects become obese the most obvious characteristic is an increase in red blood cell (RBC) aggregation correlated to the size of fat stores. It is clear that 3 months of LI are not a perfect model of "healthy primitive lifestyle", but these data suggest that the most important effect of LI regular exercise is to decrease plasma viscosity and that sedentarity increases RBC aggregation mostly when it results in increased fat storage.

Acute physiological responses to low-intensity blood flow restriction cycling.

PubMed

Thomas, H J; Scott, B R; Peiffer, J J

2018-04-09

Blood flow restriction (BFR) during interval cycling may stimulate aerobic and anaerobic adaptations. However, acute physiological responses to BFR interval cycling have not been extensively investigated. Eighteen males completed low-intensity (LI), low-intensity with BFR (LI BFR ) and high-intensity (HI) interval cycling sessions in randomised and counterbalanced order. These included a standardised warm-up and three two-min intervals interspersed with two-min recovery. Interval intensity during HI, LI and LI BFR were 85%, 40% and 40% of peak power output obtained during graded exercise tests. During LI BFR , 80% arterial occlusion was applied to both legs during the interval efforts and removed during recovery. Continuous measures of heart rate (HR), cardiac output (CO) and oxygen consumption (V˙O 2 ) were recorded. Blood pressure (BP) and rating of perceived exertion (RPE) were measured following intervals. Blood lactate concentration was measured pre- and post-exercise. BP, HR, CO, V˙O 2 , lactate and RPE were greatest during HI. During the active intervals, BP, HR and CO were greater during LI BFR than LI. V˙O 2 during recovery periods were greater in LI BFR than LI. Post-session lactate was greater during LI BFR than LI. Importantly, mean arterial pressure during interval three was significantly greater in LI BFR (124±2mmHg) than HI (114±3mmHg). LI BFR increases cardiovascular and metabolic stress compared with LI and could provide an alternative aerobic training method for individuals unable to perform high-intensity exercise. However, increases in mean arterial pressure during LI BFR indicates high myocardial workload, and practitioners should therefore use caution if prescribing LI BFR for vascular compromised individuals. Copyright © 2018 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Carbohydrate Dependence During Prolonged, Intense Endurance Exercise.

PubMed

Hawley, John A; Leckey, Jill J

2015-11-01

A major goal of training to improve the performance of prolonged, continuous, endurance events lasting up to 3 h is to promote a range of physiological and metabolic adaptations that permit an athlete to work at both higher absolute and relative power outputs/speeds and delay the onset of fatigue (i.e., a decline in exercise intensity). To meet these goals, competitive endurance athletes undertake a prodigious volume of training, with a large proportion performed at intensities that are close to or faster than race pace and highly dependent on carbohydrate (CHO)-based fuels to sustain rates of muscle energy production [i.e., match rates of adenosine triphosphate (ATP) hydrolysis with rates of resynthesis]. Consequently, to sustain muscle energy reserves and meet the daily demands of training sessions, competitive athletes freely select CHO-rich diets. Despite renewed interest in high-fat, low-CHO diets for endurance sport, fat-rich diets do not improve training capacity or performance, but directly impair rates of muscle glycogenolysis and energy flux, limiting high-intensity ATP production. When highly trained athletes compete in endurance events lasting up to 3 h, CHO-, not fat-based fuels are the predominant fuel for the working muscles and CHO, not fat, availability becomes rate limiting for performance.

High intensity exercise or conventional exercise for patients with rheumatoid arthritis? Outcome expectations of patients, rheumatologists, and physiotherapists

PubMed Central

Munneke, M; de Jong, Z; Zwinderman, A; Ronday, H; van den Ende, C H M; Vliet, V; Hazes, J

2004-01-01

Objective: To examine the outcome expectations of RA patients, rheumatologists, and physiotherapists regarding high intensity exercise programmes compared with conventional exercise programmes. Methods: An exercise outcome expectations questionnaire was administered to 807 RA patients, 153 rheumatologists, and 624 physiotherapists. The questionnaire consisted of four statements regarding positive and negative outcomes of high intensity exercise programmes and four similar statements for conventional exercise programmes. A total expectation score for both conventional and high intensity exercise was calculated, ranging from –2 (very negative expectation) to 2 (very positive expectation). Results: The questionnaire was returned by 662 RA patients (82%), 132 rheumatologists (86%), and 467 physiotherapists (75%). The mean (95% confidence interval) scores for high intensity exercise programmes were 0.30 (0.25 to 0.34), 0.68 (0.62 to 0.74), and –0.06 (–0.15 to 0.02), and for conventional exercise programmes were 0.99 (0.96 to 1.02), 1.13 (1.09 to 1.17), and 1.27 (1.21 to 1.34) for RA patients, rheumatologists, and physiotherapists, respectively. In all three respondent groups, the outcome expectations of high intensity exercise were significantly less positive than those of conventional exercise programme. Conclusions: Despite the existing evidence regarding the effectiveness and safety of high intensity exercise programmes, RA patients, rheumatologists, and physiotherapists have more positive expectations of conventional exercise programmes than of high intensity exercise programmes. Physiotherapists were the least positive about outcomes of high intensity exercise programmes while rheumatologists were the most positive. To help the implementation of new insights in the effectiveness of physical therapy modalities in rheumatology, the need for continuous education of patients, rheumatologists and physiotherapists is emphasised. PMID:15194575

[Exercise-referral to a specialist in adapted physical activity (APA) : a pilot project].

PubMed

Brugnerotto, Adeline; Cardinaux, Regula; Ueltschi, Yan; Bauwens, Marine; Nanchen, David; Cornuz, Jacques; Bize, Raphaël; Auer, Reto

2016-11-02

Family physicians have a key role in the promotion of physical activity, in particular in identifying and counseling persons who have a sedentary lifestyle. Some patients could benefit from intensive individual counseling. Physicians are often not aware of all physical activity promotion activities in the community that they could recommend their patients. In a pilot study, we have tested and adapted the referral of patients from family physicians to specialists in adapted physical activity (APAs). APAs are trained to assess and guide persons towards physical activities adapted to their needs and pathologies and thus towards an increase in physical activity. Pilot data suggest that, while few patients were oriented to the APAs in the pilot project, family physicians appreciate the possibility of collaborating with the APAs.

Influence of Exercise Intensity for Improving Depressed Mood in Depression: A Dose-Response Study.

PubMed

Meyer, Jacob D; Koltyn, Kelli F; Stegner, Aaron J; Kim, Jee-Seon; Cook, Dane B

2016-07-01

Exercise effectively improves mood in major depressive disorder (MDD), but the optimal exercise stimulus to improve depressed mood is unknown. To determine the dose-response relationship of acute exercise intensity with depressed mood responses to exercise in MDD. We hypothesized that the acute response to exercise would differ between light, moderate, and hard intensity exercise with higher intensities yielding more beneficial responses. Once weekly, 24 women (age: 38.6±14.0) diagnosed with MDD underwent a 30-minute session at one of three steady-state exercise intensities (light, moderate, hard; rating of perceived exertion 11, 13 or 15) or quiet rest on a stationary bicycle. Depressed mood was evaluated with the Profile of Mood States before, 10 and 30 minutes post-exercise. Exercise reduced depressed mood 10 and 30 minutes following exercise, but this effect was not influenced by exercise intensity. Participants not currently taking antidepressants (n=10) had higher baseline depression scores, but did not demonstrate a different antidepressant response to exercise compared to those taking antidepressants. To acutely improve depressed mood, exercise of any intensity significantly improved feelings of depression with no differential effect following light, moderate, or hard exercise. Pharmacological antidepressant usage did not limit the mood-enhancing effect of acute exercise. Acute exercise should be used as a symptom management tool to improve mood in depression, with even light exercise an effective recommendation. These results need to be replicated and extended to other components of exercise prescription (e.g., duration, frequency, mode) to optimize exercise guidelines for improving depression. Copyright © 2016. Published by Elsevier Ltd.

High-intensity exercise training induces morphological and biochemical changes in skeletal muscles.

PubMed

Toti, L; Bartalucci, A; Ferrucci, M; Fulceri, F; Lazzeri, G; Lenzi, P; Soldani, P; Gobbi, P; La Torre, A; Gesi, M

2013-12-01

IN THE PRESENT STUDY WE INVESTIGATED THE EFFECT OF TWO DIFFERENT EXERCISE PROTOCOLS ON FIBRE COMPOSITION AND METABOLISM OF TWO SPECIFIC MUSCLES OF MICE: the quadriceps and the gastrocnemius. Mice were run daily on a motorized treadmill, at a velocity corresponding to 60% or 90% of the maximal running velocity. Blood lactate and body weight were measured during exercise training. We found that at the end of training the body weight significantly increased in high-intensity exercise mice compared to the control group (P=0.0268), whereas it decreased in low-intensity exercise mice compared to controls (P=0.30). In contrast, the food intake was greater in both trained mice compared to controls (P < 0.0001 and P < 0.0001 for low-intensity and high-intensity exercise mice, respectively). These effects were accompanied by a progressive reduction in blood lactate levels at the end of training in both the exercised mice compared with controls (P=0.03 and P < 0.0001 for low-intensity and high-intensity exercise mice, respectively); in particular, blood lactate levels after high-intensity exercise were significantly lower than those measured in low-intensity exercise mice (P=0.0044). Immunoblotting analysis demonstrated that high-intensity exercise training produced a significant increase in the expression of mitochondrial enzymes contained within gastrocnemius and quadriceps muscles. These changes were associated with an increase in the amount of slow fibres in both these muscles of high-intensity exercise mice, as revealed by the counts of slow fibres stained with specific antibodies (P < 0.0001 for the gastrocnemius; P=0.0002 for the quadriceps). Our results demonstrate that high-intensity exercise, in addition to metabolic changes consisting of a decrease in blood lactate and body weight, induces an increase in the mitochondrial enzymes and slow fibres in different skeletal muscles of mice, which indicates an exercise-induced increase in the aerobic metabolism.

Biochemical changes in response to intensive resistance exercise training in the elderly.

PubMed

Bautmans, Ivan; Njemini, Rose; Vasseur, Sabine; Chabert, Hans; Moens, Lisa; Demanet, Christian; Mets, Tony

2005-01-01

It is assumed that low-grade inflammation, characterized by increased circulating IL-6 and TNF-alpha, is related to the development of sarcopenia. Physical exercise, especially high intensity resistance training, has been shown to be effective in restoring the strength deficit in the elderly. Intensive exercise is accompanied by significant release of IL-6 and TNF-alpha into the blood circulation, but does not result in muscle wasting. Exercise-induced changes in heat-shock protein (Hsp), responsible for cellular protection during stressful situations, might interfere with the acute phase reaction and muscle adaptation. To investigate if intensive strength training in elderly persons induces changes in Hsp70 expression, and if these changes are related to changes in the acute phase reaction or muscle adaptation. 31 elderly persons (aged 68.4+/-5.4 years) performed 6 weeks' intensive strength training. At baseline and after 6 weeks, muscle strength, functional performance (physical activity profile, 6-min walk, 30- second chair stand, grip strength, chair sit & reach and back scratch), linear isokinetic leg extension, circulating IL-6, TNF-alpha, IL-10 and TGF-beta, and Hsp70 in monocytes (M) and lymphocytes (L) immediately after sampling (IAS), after incubation at 37 and 42 degrees C were determined. In 12 participants, cytokines were determined in untrained and trained conditions before and after a single training session. After 6 weeks' training, muscle strength and functional performance improved significantly, together with decreased Hsp70 IAS and Hsp70 37 degrees C and increased Hsp70 42 degrees C (all p<0.05). Strength gains correlated positively with baseline Hsp70 37 degrees C and training-induced changes of Hsp70 42 degrees C in M and L. In an untrained condition, training induced an increase of IL-6 (p<0.05) and a tendency of IL-10 to decrease (p=0.06). In a trained condition the decrease of IL-10 disappeared. Baseline physical activity and 6-min walk distance correlated negatively with circulating IL-6 (p<0.05); except for a negative correlation between TGF-beta and Hsp70 37 degrees C L (p<0.05), no significant relationships were found between cytokines and Hsp70. After the training program, Hsp70 37 degrees C was negatively related to circulating TNF-alpha, IL-10 and TGF-beta. Strength training in the elderly induces changes in Hsp70 expression, associated to strength gains and circulating cytokines. Copyright (c) 2005 S. Karger AG, Basel.

Effects of high-intensity intermittent training on carnitine palmitoyl transferase activity in the gastrocnemius muscle of rats

PubMed Central

Carnevali, L.C.; Eder, R.; Lira, F.S.; Lima, W.P.; Gonçalves, D.C.; Zanchi, N.E.; Nicastro, H.; Lavoie, J.M.; Seelaender, M.C.L.

2012-01-01

We examined the capacity of high-intensity intermittent training (HI-IT) to facilitate the delivery of lipids to enzymes responsible for oxidation, a task performed by the carnitine palmitoyl transferase (CPT) system in the rat gastrocnemius muscle. Male adult Wistar rats (160-250 g) were randomly distributed into 3 groups: sedentary (Sed, N = 5), HI-IT (N = 10), and moderate-intensity continuous training (MI-CT, N = 10). The trained groups were exercised for 8 weeks with a 10% (HI-IT) and a 5% (MI-CT) overload. The HI-IT group presented 11.8% decreased weight gain compared to the Sed group. The maximal activities of CPT-I, CPT-II, and citrate synthase were all increased in the HI-IT group compared to the Sed group (P < 0.01), as also was gene expression, measured by RT-PCR, of fatty acid binding protein (FABP; P < 0.01) and lipoprotein lipase (LPL; P < 0.05). Lactate dehydrogenase also presented a higher maximal activity (nmol·min−1·mg protein−1) in HI-IT (around 83%). We suggest that 8 weeks of HI-IT enhance mitochondrial lipid transport capacity thus facilitating the oxidation process in the gastrocnemius muscle. This adaptation may also be associated with the decrease in weight gain observed in the animals and was concomitant to a higher gene expression of both FABP and LPL in HI-IT, suggesting that intermittent exercise is a “time-efficient” strategy inducing metabolic adaptation. PMID:22735180

Evidence for cognitive–behavioral strategies improving dyspnea and related distress in COPD

PubMed Central

Norweg, Anna; Collins, Eileen G

2013-01-01

Background Dyspnea is a complex, prevalent, and distressing symptom of chronic obstructive pulmonary disease (COPD) associated with decreased quality of life, significant disability, and increased mortality. It is a major reason for referral to pulmonary rehabilitation. Methods We reviewed 23 COPD studies to examine the evidence for the effectiveness of cognitive–behavioral strategies for relieving dyspnea in COPD. Results Preliminary evidence from randomized controlled trials exists to support cognitive– behavioral strategies, used with or without exercise, for relieving sensory and affective components of dyspnea in COPD. Small to moderate treatment effects for relieving dyspnea were noted for psychotherapy (effect size [ES] = 0.08–0.25 for intensity; 0.26–0.65 for mastery) and distractive auditory stimuli (ES = 0.08–0.33 for intensity; 0.09 to −0.61 for functional burden). Small to large dyspnea improvements resulted from yoga (ES = 0.2–1.21 for intensity; 0.67 for distress; 0.07 for mastery; and −8.37 for functional burden); dyspnea self-management education with exercise (ES = −0.14 to −1.15 for intensity; −0.62 to −0.69 for distress; 1.04 for mastery; 0.14–0.35 for self-efficacy); and slow-breathing exercises (ES = −0.34 to −0.83 for intensity; −0.61 to −0.80 for distress; and 0.62 for self-efficacy). Cognitive–behavioral interventions may relieve dyspnea in COPD by (1) decreasing sympathetic nerve activity, dynamic hyperinflation, and comorbid anxiety, and (2) promoting arterial oxygen saturation, myelinated vagus nerve activity, a greater exercise training effect, and neuroplasticity. Conclusion While evidence is increasing, additional randomized controlled trials are needed to evaluate the effectiveness of psychosocial and self-management interventions in relieving dyspnea, in order to make them more available to patients and to endorse them in official COPD, dyspnea, and pulmonary rehabilitation practice guidelines. By relieving dyspnea and related anxiety, such interventions may promote adherence to exercise programs and adaptive lifestyle change. PMID:24106423

High-Intensity Locomotor Exercise Increases Brain-Derived Neurotrophic Factor in Individuals with Incomplete Spinal Cord Injury.

PubMed

Leech, Kristan A; Hornby, T George

2017-03-15

High-intensity locomotor exercise is suggested to contribute to improved recovery of locomotor function after neurological injury. This may be secondary to exercise-intensity-dependent increases in neurotrophin expression demonstrated previously in control subjects. However, rigorous examination of intensity-dependent changes in neurotrophin levels is lacking in individuals with motor incomplete spinal cord injury (SCI). Therefore, the primary aim of this study was to evaluate the effect of locomotor exercise intensity on peripheral levels of brain-derived neurotrophic factor (BDNF) in individuals with incomplete SCI. We also explored the impact of the Val66Met single-nucleotide polymorphism (SNP) on the BDNF gene on intensity-dependent changes. Serum concentrations of BDNF and insulin-like growth factor-1 (IGF-1), as well as measures of cardiorespiratory dynamics, were evaluated across different levels of exercise intensity achieved during a graded-intensity, locomotor exercise paradigm in 11 individuals with incomplete SCI. Our results demonstrate a significant increase in serum BDNF at high, as compared to moderate, exercise intensities (p = 0.01) and 15 and 30 min post-exercise (p < 0.01 for both), with comparison to changes at low intensity approaching significance (p = 0.05). Serum IGF-1 demonstrated no intensity-dependent changes. Significant correlations were observed between changes in BDNF and specific indicators of exercise intensity (e.g., rating of perceived exertion; R = 0.43; p = 0.02). Additionally, the data suggest that Val66Met SNP carriers may not exhibit intensity-dependent changes in serum BDNF concentration. Given the known role of BDNF in experience-dependent neuroplasticity, these preliminary results suggest that exercise intensity modulates serum BDNF concentrations and may be an important parameter of physical rehabilitation interventions after neurological injury.

[The benefits of doing excercise in the elderly].

PubMed

Avila-Funes, José Alberto; García-Mayo, Emilio José

2004-01-01

Advanced age is associated with changes in body composition such as muscular mass loss, which is defined as sarcopenia. The former term plays a key role in the frailty model, although its source is unknown. Myriad strategies have been used to improve and increase muscular mass and function in older persons. The muscle is a versatile system that owes its great capacity to adaption to regular exercise programs. Aerobic exercise and resistance training improve muscular function and can minimize and even reverse sarcopenia in the elderly (healthy, very elderly or frail). The main difference in prescribing exercise for healthy adults and elderly individuals is that intensity of training program is lower for the latter. This review is aimed toward the physiopathologic aspects and clinical implications regarding muscular mass loss and to programs directed toward increasing strength and/or endurance in the elderly.

Influence of Exercise and Training on Critical Stages of Bone Growth and Development.

PubMed

Klentrou, Panagiota

2016-05-01

Although osteoporosis is considered a geriatric disease, factors affecting bone strength are most influential during child growth and development. This article reviews what is known and still unclear in terms of bone growth, development and adaptation relative to physical activity before and during puberty. Bone is responsive to certain exercise protocols early in puberty and less so in postpubertal years, where bone strength, rather than bone mass, being the outcome of interest. Mechanical loading and high impact exercise promote bone strength. Intense training before and during puberty, however, may negatively affect bone development. Future research should focus on increasing our mechanistic understanding of the manner by which diverse physical stressors alter the integrity of bone. Longitudinal studies that examine the extent to which muscle and bone are comodulated by growth in children are also recommended.

Update on the effects of physical activity on insulin sensitivity in humans

PubMed Central

Bird, Stephen R; Hawley, John A

2016-01-01

Purpose and methods This review presents established knowledge on the effects of physical activity (PA) on whole-body insulin sensitivity (SI) and summarises the findings of recent (2013–2016) studies. Discussion and conclusions Recent studies provide further evidence to support the notion that regular PA reduces the risk of insulin resistance, metabolic syndrome and type 2 diabetes, and SI improves when individuals comply with exercise and/or PA guidelines. Many studies indicate a dose response, with higher energy expenditures and higher exercise intensities, including high intensity interval training (HIIT), producing greater benefits on whole-body SI, although these findings are not unanimous. Aerobic exercise interventions can improve SI without an associated increase in cardiorespiratory fitness as measured by maximal or peak oxygen consumption. Both aerobic and resistance exercise can induce improvements in glycaemic regulation, with some suggestions that exercise regimens including both may be more efficacious than either exercise mode alone. Some studies report exercise-induced benefits to SI that are independent of habitual diet and weight loss, while others indicate an association with fat reduction, hence the debate over the relative importance of PA and weight loss continues. During exercise, muscle contraction stimulated improvements in SI are associated with increases in AMPK activity, which deactivates TCB1D1, promoting GLUT4 translocation to the cell membrane and thereby increasing glucose uptake. Postexercise, increases in Akt deactivate TCB1D4 and thereby increase GLUT4 translocation to the cell membrane. The reduction in intramuscular saturated fatty acids and concomitant reductions in ceramides, but not diacylglycerols, provide a potential link between intramuscular lipid content and SI. Increased skeletal muscle capillarisation provides another independent adaptation through which SI is improved, as does enhanced β cell activity. Recent studies are combining exercise interventions with dietary and feeding manipulations to investigate the potential for augmenting the exercise-induced improvements in SI and glycaemic control. PMID:28879026

Update on the effects of physical activity on insulin sensitivity in humans.

PubMed

Bird, Stephen R; Hawley, John A

2016-01-01

This review presents established knowledge on the effects of physical activity (PA) on whole-body insulin sensitivity (SI) and summarises the findings of recent (2013-2016) studies. Recent studies provide further evidence to support the notion that regular PA reduces the risk of insulin resistance, metabolic syndrome and type 2 diabetes, and SI improves when individuals comply with exercise and/or PA guidelines. Many studies indicate a dose response, with higher energy expenditures and higher exercise intensities, including high intensity interval training (HIIT), producing greater benefits on whole-body SI, although these findings are not unanimous. Aerobic exercise interventions can improve SI without an associated increase in cardiorespiratory fitness as measured by maximal or peak oxygen consumption. Both aerobic and resistance exercise can induce improvements in glycaemic regulation, with some suggestions that exercise regimens including both may be more efficacious than either exercise mode alone. Some studies report exercise-induced benefits to SI that are independent of habitual diet and weight loss, while others indicate an association with fat reduction, hence the debate over the relative importance of PA and weight loss continues. During exercise, muscle contraction stimulated improvements in SI are associated with increases in AMPK activity, which deactivates TCB1D1, promoting GLUT4 translocation to the cell membrane and thereby increasing glucose uptake. Postexercise, increases in Akt deactivate TCB1D4 and thereby increase GLUT4 translocation to the cell membrane. The reduction in intramuscular saturated fatty acids and concomitant reductions in ceramides, but not diacylglycerols, provide a potential link between intramuscular lipid content and SI. Increased skeletal muscle capillarisation provides another independent adaptation through which SI is improved, as does enhanced β cell activity. Recent studies are combining exercise interventions with dietary and feeding manipulations to investigate the potential for augmenting the exercise-induced improvements in SI and glycaemic control.

Can previously sedentary females use the feeling scale to regulate exercise intensity in a gym environment? an observational study.

PubMed

Hamlyn-Williams, Charlotte C; Tempest, Gavin; Coombs, Sarah; Parfitt, Gaynor

2015-01-01

Recent research suggests that the Feeling Scale (FS) can be used as a method of exercise intensity regulation to maintain a positive affective response during exercise. However, research to date has been carried out in laboratories and is not representative of natural exercise environments. The purpose of this study was to evaluate whether sedentary women can self-regulate their exercise intensity using the FS to experience positive affective responses in a gym environment using their own choice of exercise mode; cycling or treadmill. Fourteen females (24.9 years ± 5.2; height 166.7 ± 5.7 cm; mass 66.3 ± 13.4 kg; BMI 24.1 ± 5.5)) completed a submaximal exercise test and each individual's ventilatory threshold ([Formula: see text]) was identified. Following this, three 20 min gym-based exercise trials, either on a bike or treadmill were performed at an intensity that was self-selected and perceived to correspond to the FS value of +3 (good). Oxygen uptake, heart rate (HR) and ratings of perceived exertion (RPE) were measured during exercise at the participants chosen intensity. Results indicated that on average participants worked close to their [Formula: see text] and increased their exercise intensity during the 20-min session. Participants worked physiologically harder during cycling exercise. Consistency of oxygen uptake, HR and RPE across the exercise trials was high. The data indicate that previously sedentary women can use the FS in an ecological setting to regulate their exercise intensity and that regulating intensity to feel 'good' should lead to individuals exercising at an intensity that would result in cardiovascular gains if maintained.

Glucose response to exercise in the post-prandial period is independent of exercise intensity.

PubMed

Shambrook, P; Kingsley, M I; Wundersitz, D W; Xanthos, P D; Wyckelsma, V L; Gordon, B A

2018-03-01

This study investigated the acute glucose response to low-intensity, moderate-intensity, and high-intensity interval exercise compared to no-exercise in healthy insufficiently active males using a four-arm, randomized, crossover design. Ten males (age: 37.3 ± 7.3 years, BMI: 29.3 ± 6.5 kg·m -2 ) completed four 30-minute interventions at weekly intervals comprising low-intensity exercise (LIE) at ~35% V˙O 2 R, moderate-intensity exercise (MIE) at ~50% V˙O 2 R, high-intensity interval exercise (HIIE) at ~80% V˙O 2 R, and a no-exercise control. Participants performed cycle ergometer exercise 30 minutes after finishing breakfast. Glucose response was assessed using a continuous glucose monitor under free-living conditions with dietary intake replicated. A significant effect for intensity on energy expenditure was identified (P < .001) with similar energy cost in MIE (mean ± SD: 869 ± 148 kJ) and HIIE (806 ± 145 kJ), which were both greater than LIE (633 ± 129 kJ). The pattern of glucose response between the interventions over time was different (P = .02). Glucose was lower 25 minutes into each of the HIIE, MIE and LIE trials respectively (mean difference ± SD: -0.7 ± 1.1; -0.9 ± 1.1; -0.6 ± 0.9 mmol·L -1 ; P < .05) than in the no-exercise trial. Glucose response was not different between exercise intensities (P > .05). Twenty-four-hour AUC was not affected by exercise intensity (P = .75). There was a significant effect for exercise enjoyment (P = .02), with LIE (69 ± 4) preferred less than HIIE (mean ± SD: 84 ± 14; P = .02), MIE (73 ± 5; P = .03), and no-exercise (75 ± 4; P = .03). Exercise at any intensity 30 minutes after a meal affects glycemic regulation equally in insufficiently active males. Moderate to vigorous exercise intensities were preferred, and therefore, the exercise guidelines appear appropriate for the prevention of cardiometabolic disease. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Low-Carbohydrate-High-Fat Diet: Can it Help Exercise Performance?

PubMed Central

Borer, Katarina; Lin, Po-Ju

2017-01-01

Abstract Low-carbohydrate-high-fat (LCHF) diets have been used as a means of weight loss and control of symptoms in several clinical conditions. There is emerging evidence that the metabolic changes induced by LCHF diets enhance endurance performance. The aims of this review are to examine the evidence of LCHF diets in improving various aspects of athletic performance. Long-term LCHF dietary intake may help control body weight and fat mass while maintaining lean body mass in athletes in weight-sensitive sports. LCHF-adapted endurance athletes can reach the maximal fat oxidation rate of approximately 1.5 g/min, with a lower carbohydrate oxidation rate and similar muscle glycogen content and a resynthesis rate compared to their counterparts consuming high-carbohydrate-low-fat (HCLF) diets. The elevated fat oxidation rate and glycogen sparing effect may improve performance in ultra-endurance events. These metabolic changes may also prevent the decline in performance in later stages of repeated high-intensity movements, in which the aerobic metabolism becomes more important. However, elevated blood concentrations of non-esterified fatty acids and ammonia during exercise after LCHF diets may lead to early development of central fatigue. It appears that at least several months of adaptation to a LCHF diet are required for the metabolic changes and restoration of muscle glycogen to occur. Further investigations on LCHF diets are needed regarding (1) performance after weight loss in weight-categorized sports; (2) repeated high-intensity exercise performance; (3) development of central fatigue during endurance events; (4) perceptual-motor performance during prolonged intermittent sports; and (5) ideal dietary fatty acid compositions. PMID:28469746

Low-Carbohydrate-High-Fat Diet: Can it Help Exercise Performance?

PubMed

Chang, Chen-Kang; Borer, Katarina; Lin, Po-Ju

2017-02-01

Low-carbohydrate-high-fat (LCHF) diets have been used as a means of weight loss and control of symptoms in several clinical conditions. There is emerging evidence that the metabolic changes induced by LCHF diets enhance endurance performance. The aims of this review are to examine the evidence of LCHF diets in improving various aspects of athletic performance. Long-term LCHF dietary intake may help control body weight and fat mass while maintaining lean body mass in athletes in weight-sensitive sports. LCHF-adapted endurance athletes can reach the maximal fat oxidation rate of approximately 1.5 g/min, with a lower carbohydrate oxidation rate and similar muscle glycogen content and a resynthesis rate compared to their counterparts consuming high-carbohydrate-low-fat (HCLF) diets. The elevated fat oxidation rate and glycogen sparing effect may improve performance in ultra-endurance events. These metabolic changes may also prevent the decline in performance in later stages of repeated high-intensity movements, in which the aerobic metabolism becomes more important. However, elevated blood concentrations of non-esterified fatty acids and ammonia during exercise after LCHF diets may lead to early development of central fatigue. It appears that at least several months of adaptation to a LCHF diet are required for the metabolic changes and restoration of muscle glycogen to occur. Further investigations on LCHF diets are needed regarding (1) performance after weight loss in weight-categorized sports; (2) repeated high-intensity exercise performance; (3) development of central fatigue during endurance events; (4) perceptual-motor performance during prolonged intermittent sports; and (5) ideal dietary fatty acid compositions.

Neoagarotetraose protects mice against intense exercise induced stress by modulating gut microbial composition and function

USDA-ARS?s Scientific Manuscript database

Exhaustive exercise stress has emerged as an important health issue, and gastrointestinal problems are a common concern during intense exercise. In this study, we investigated potential anti-fatigue effects of neoagarotetraose (NAT) in mice under intense exercise stress. Exhaustive exercise stress s...

Redox signaling in skeletal muscle: role of aging and exercise.

PubMed

Ji, Li Li

2015-12-01

Skeletal muscle contraction is associated with the production of ROS due to altered O2 distribution and flux in the cell. Despite a highly efficient antioxidant defense, a small surplus of ROS, such as hydrogen peroxide and nitric oxide, may serve as signaling molecules to stimulate cellular adaptation to reach new homeostasis largely due to the activation of redox-sensitive signaling pathways. Recent research has highlighted the important role of NF-κB, MAPK, and peroxisome proliferator-activated receptor-γ coactivator-1α, along with other newly discovered signaling pathways, in some of the most vital biological functions, such as mitochondrial biogenesis, antioxidant defense, inflammation, protein turnover, apoptosis, and autophagy. There is evidence that the inability of the cell to maintain proper redox signaling underlies some basic mechanisms of biological aging, during which inflammatory and catabolic pathways eventually predominate. Physical exercise has been shown to activate various redox signaling pathways that control the adaptation and remodeling process. Although this stimulatory effect of exercise declines with aging, it is not completed abolished. Thus, aged people can still benefit from regular physical activity in the appropriate forms and at proper intensity to preserve muscle function. Copyright © 2015 The American Physiological Society.

A New Adaptive Home-based Exercise Technology among Older Adults Living in Nursing Home: A Pilot Study on Feasibility, Acceptability and Physical Performance.

PubMed

Valiani, V; Lauzé, M; Martel, D; Pahor, M; Manini, T M; Anton, S; Aubertin-Leheudre, M

2017-01-01

To explore the feasibility and acceptability of a new home-based exercise technology among older adults and to evaluate its efficacy on physical performance measures. Longitudinal clinical trial. Oak Hammock at the University of Florida, a nursing home located in Gainesville, Florida. Twelve pre-disabled older adults (≥75 years) living in a nursing home with a Short Physical Performance Battery (SPPB) score between 6 and 9 and no diagnosis of dementia. Thirty minutes of light intensity exercise (aerobic, strength and balance) two times per week for four weeks using a home-based physical activity technology called Jintronix. Feasibility and acceptability were assessed through a 9-item self-administered questionnaire and by exploring the percentage of quality of movements and time performing exercise which was calculated automatically by Jintronix technology. Physical performance measures were assessed through the SPPB score at baseline, after 4 weeks of intervention and after 3 months from the completion of the intervention. Twelve older adults (80.5±4.2 years old) performed light intensity exercise with Jintronix for a total of 51.9±7.9 minutes per week. Participants reached 87% score of quality of movements in strength and balance exercises, a global appreciation score of 91.7% and a global difficulty score of 36%. Compared to baseline, there was a significant improvement in SPPB score at the end of the intervention and at 3 months following the completion of the exercise program (0.67±0.98 and 1.08±0.99 respectively, p-value <0.05). Jintronix technology is feasible and acceptable among pre-disabled older adults without dementia living in nursing home and is beneficial in improving their physical performance.

Music enhances performance and perceived enjoyment of sprint interval exercise.

PubMed

Stork, Matthew J; Kwan, Matthew Y W; Gibala, Martin J; Martin Ginis, Kathleen A

2015-05-01

Interval exercise training can elicit physiological adaptations similar to those of traditional endurance training, but with reduced time. However, the intense nature of specific protocols, particularly the "all-out" efforts characteristic of sprint interval training (SIT), may be perceived as being aversive. The purpose of this study was to determine whether listening to self-selected music can reduce the potential aversiveness of an acute session of SIT by improving affect, motivation, and enjoyment, and to examine the effects of music on performance. Twenty moderately active adults (22 ± 4 yr) unfamiliar with interval exercise completed an acute session of SIT under two different conditions: music and no music. The exercise consisted of four 30-s "all-out" Wingate Anaerobic Test bouts on a cycle ergometer, separated by 4 min of rest. Peak and mean power output, RPE, affect, task motivation, and perceived enjoyment of the exercise were measured. Mixed-effects models were used to evaluate changes in dependent measures over time and between the two conditions. Peak and mean power over the course of the exercise session were higher in the music condition (coefficient = 49.72 [SE = 13.55] and coefficient = 23.65 [SE = 11.30]; P < 0.05). A significant time by condition effect emerged for peak power (coefficient = -12.31 [SE = 4.95]; P < 0.05). There were no between-condition differences in RPE, affect, or task motivation. Perceived enjoyment increased over time and was consistently higher in the music condition (coefficient = 7.00 [SE = 3.05]; P < 0.05). Music enhances in-task performance and enjoyment of an acute bout of SIT. Listening to music during intense interval exercise may be an effective strategy for facilitating participation in, and adherence to, this form of training.

High-Intensity Locomotor Exercise Increases Brain-Derived Neurotrophic Factor in Individuals with Incomplete Spinal Cord Injury

PubMed Central

Leech, Kristan A.

2017-01-01

Abstract High-intensity locomotor exercise is suggested to contribute to improved recovery of locomotor function after neurological injury. This may be secondary to exercise-intensity–dependent increases in neurotrophin expression demonstrated previously in control subjects. However, rigorous examination of intensity-dependent changes in neurotrophin levels is lacking in individuals with motor incomplete spinal cord injury (SCI). Therefore, the primary aim of this study was to evaluate the effect of locomotor exercise intensity on peripheral levels of brain-derived neurotrophic factor (BDNF) in individuals with incomplete SCI. We also explored the impact of the Val66Met single-nucleotide polymorphism (SNP) on the BDNF gene on intensity-dependent changes. Serum concentrations of BDNF and insulin-like growth factor-1 (IGF-1), as well as measures of cardiorespiratory dynamics, were evaluated across different levels of exercise intensity achieved during a graded-intensity, locomotor exercise paradigm in 11 individuals with incomplete SCI. Our results demonstrate a significant increase in serum BDNF at high, as compared to moderate, exercise intensities (p = 0.01) and 15 and 30 min post-exercise (p < 0.01 for both), with comparison to changes at low intensity approaching significance (p = 0.05). Serum IGF-1 demonstrated no intensity-dependent changes. Significant correlations were observed between changes in BDNF and specific indicators of exercise intensity (e.g., rating of perceived exertion; R = 0.43; p = 0.02). Additionally, the data suggest that Val66Met SNP carriers may not exhibit intensity-dependent changes in serum BDNF concentration. Given the known role of BDNF in experience-dependent neuroplasticity, these preliminary results suggest that exercise intensity modulates serum BDNF concentrations and may be an important parameter of physical rehabilitation interventions after neurological injury. PMID:27526567

Can Self-Reported Preference for Exercise Intensity Predict Physiologically Defined Self-Selected Exercise Intensity?

ERIC Educational Resources Information Center

Ekkekakis, Panteleimon; Lind, Erik; Joens-Matre, Roxane R.

2006-01-01

Exercise prescription guidelines emphasize the importance of individual preferences for different intensities, but such preferences have not been studied systematically. This study examined the hypothesis that the preference scale of the Preference for and Tolerance of the Intensity of Exercise Questionnaire would predict self-selected exercise…

Effect of the low- versus high-intensity exercise training on endoplasmic reticulum stress and GLP-1 in adolescents with type 2 diabetes mellitus.

PubMed

Lee, Sung Soo; Yoo, Jae Ho; So, Yong Seok

2015-10-01

[Purpose] The primary objective of this study was to investigate the effect of low-intensity exercise training compare with high-intensity exercise training on endoplasmic reticulum stress and glucagon-like peptide-1 in adolescents with type 2 diabetes mellitus. [Subjects and Methods] The low-intensity exercise training group performed aerobic exercise training at an intensity of ≤ 45% of the heart rate reserve. The high-intensity interval exercise training group performed interval exercise training at an intensity of ≥ 80% of the heart rate reserve. The exercise-related energy consumption was determined for both groups on a per-week basis (1,200 kcal/week). [Results] Both groups showed improvement in the glucose-regulated protein 78 and dipeptidyl peptidase-4, but the size of the between-group effect was not statistically significant. The high-intensity interval exercise training group showed a significant reduction in percentage body fat. The C-peptide level increased after the 12-weeks programs and was significantly different, between the groups. Fasting glucose, insulin resistance in the fasting state according to homeostasis model assessment, and leptin decreased after the 12-weeks exercise program and were significantly different between the groups, and glucagon-like peptide-1 increased after the 12-week exercise programs and was significantly different between the groups. [Conclusion] In conclusion high-intensity interval exercise training, as defined in this study, may lead to improvements in body composition, glycemic control, endoplasmic reticulum stress, and the glucagon-like peptide-1 in adolescents with type 2 diabetes mellitus.

Effect of the low- versus high-intensity exercise training on endoplasmic reticulum stress and GLP-1 in adolescents with type 2 diabetes mellitus

PubMed Central

Lee, Sung Soo; Yoo, Jae Ho; So, Yong Seok

2015-01-01

[Purpose] The primary objective of this study was to investigate the effect of low-intensity exercise training compare with high-intensity exercise training on endoplasmic reticulum stress and glucagon-like peptide-1 in adolescents with type 2 diabetes mellitus. [Subjects and Methods] The low-intensity exercise training group performed aerobic exercise training at an intensity of ≤ 45% of the heart rate reserve. The high-intensity interval exercise training group performed interval exercise training at an intensity of ≥ 80% of the heart rate reserve. The exercise-related energy consumption was determined for both groups on a per-week basis (1,200 kcal/week). [Results] Both groups showed improvement in the glucose-regulated protein 78 and dipeptidyl peptidase-4, but the size of the between-group effect was not statistically significant. The high-intensity interval exercise training group showed a significant reduction in percentage body fat. The C-peptide level increased after the 12-weeks programs and was significantly different, between the groups. Fasting glucose, insulin resistance in the fasting state according to homeostasis model assessment, and leptin decreased after the 12-weeks exercise program and were significantly different between the groups, and glucagon-like peptide-1 increased after the 12-week exercise programs and was significantly different between the groups. [Conclusion] In conclusion high-intensity interval exercise training, as defined in this study, may lead to improvements in body composition, glycemic control, endoplasmic reticulum stress, and the glucagon-like peptide-1 in adolescents with type 2 diabetes mellitus. PMID:26644644

Energy cost of isolated resistance exercises across low- to high-intensities

PubMed Central

Garrido, Nuno Domingos; Vianna, Jeferson; Sousa, Ana Catarina; Alves, José Vilaça; Marques, Mário Cardoso

2017-01-01

This study aimed to estimate the energy cost across various intensities at eight popular resistance exercises: half squat, 45° inclined leg press, leg extension, horizontal bench press, 45° inclined bench press, lat pull down, triceps extension and biceps curl. 58 males (27.5 ± 4.9 years, 1.78 ± 0.06 m height, 78.67 ± 10.7 kg body mass and 11.4 ± 4.1% estimated body fat) were randomly divided into four groups of 14 subjects each. For each group, two exercises were randomly assigned and on different days, they performed four bouts of 5-min constant-intensity for each of the two assigned exercises: 12%, 16%, 20% and 24% 1-RM. Later, the subjects performed exhaustive bouts at 80% 1-RM in the same two exercises. The mean values of VO2 at the last 30s of exercise at 12, 16, 20 and 24% 1-RM bouts were plotted against relative intensity (% 1-RM) in a simple linear regression mode. The regressions were then used to predict O2 demand for the higher intensity (80% 1-RM). Energy cost rose linearly with exercise intensity in every exercise with the lowest mean values were found in biceps curl and the highest in half squat exercise (p<0.001). Half squat exercise presented significant (p<0.001) higher values of energy cost in all intensities, when compared with the remaining exercises. This study revealed that low-intensity resistance exercise provides energy cost comprised between 3 and 10 kcal∙min-1. Energy cost rose past 20 kcal∙min-1 at 80% 1-RM in leg exercise. In addition, at 80% 1-RM, it was found that upper body exercises are less anaerobic than lower-body exercises. PMID:28742112

p38 MAPK activation and H3K4 trimethylation is decreased by lactate in vitro and high intensity resistance training in human skeletal muscle.

PubMed

Willkomm, Lena; Gehlert, Sebastian; Jacko, Daniel; Schiffer, Thorsten; Bloch, Wilhelm

2017-01-01

Exercise induces adaptation of skeletal muscle by acutely modulating intracellular signaling, gene expression, protein turnover and myogenic activation of skeletal muscle stem cells (Satellite cells, SCs). Lactate (La)-induced metabolic stimulation alone has been shown to modify SC proliferation and differentiation. Although the mechanistic basis remains elusive, it was demonstrated that La affects signaling via p38 mitogen activated protein kinase (p38 MAPK) which might contribute to trimethylation of histone 3 lysine 4 (H3K4me3) known to regulate satellite cell proliferation and differentiation. We investigated the effects of La on p38 MAPK and H3K4me3 in a model of activated SCs. Differentiating C2C12 myoblasts were treated with La (20 mM) and samples analysed using qRT-PCR, immunofluorescence, and western blotting. We determined a reduction of p38 MAPK phosphorylation, decreased H3K4me3 and reduced expression of Myf5, myogenin, and myosin heavy chain (MHC) leading to decreased differentiation of La-treated C2C12 cells after 5 days of repeated La treatment. We further investigated whether this regulatory pathway would be affected in human skeletal muscle by the application of two different resistance exercise regimes (RE) associated with distinct metabolic demands and blood La accumulation. Muscle biopsies were obtained 15, 30 min, 1, 4, and 24 h post exercise after moderate intensity RE (STD) vs. high intensity RE (HIT). Consistent with in vitro results, reduced p38 phosphorylation and blunted H3K4me3 were also observed upon metabolically demanding HIT RE in human skeletal muscle. Our data provide evidence that La-accumulation acutely affects p38 MAPK signaling, gene expression and thereby cell differentiation and adaptation in vitro, and likely in vivo.

Effects of increasing and decreasing physiological arousal on anticipation timing performance during competition and practice.

PubMed

Duncan, Michael J; Smith, Mike; Bryant, Elizabeth; Eyre, Emma; Cook, Kathryn; Hankey, Joanne; Tallis, Jason; Clarke, Neil; Jones, Marc V

2016-01-01

The aim of this study was to investigate if the effects of changes in physiological arousal on timing performance can be accurately predicted by the catastrophe model. Eighteen young adults (8 males, 10 females) volunteered to participate in the study following ethical approval. After familiarisation, coincidence anticipation was measured using the Bassin Anticipation Timer under four incremental exercise conditions: Increasing exercise intensity and low cognitive anxiety, increasing exercise intensity and high cognitive anxiety, decreasing exercise intensity and low cognitive anxiety and decreasing exercise intensity and high cognitive anxiety. Incremental exercise was performed on a treadmill at intensities of 30%, 50%, 70% and 90% heart rate reserve (HRR) respectively. Ratings of cognitive anxiety were taken at each intensity using the Mental Readiness Form 3 (MRF3) followed by performance of coincidence anticipation trials at speeds of 3 and 8 mph. Results indicated significant condition × intensity interactions for absolute error (AE; p = .0001) and MRF cognitive anxiety intensity scores (p = .05). Post hoc analysis indicated that there were no statistically significant differences in AE across exercise intensities in low-cognitive anxiety conditions. In high-cognitive anxiety conditions, timing performance AE was significantly poorer and cognitive anxiety higher at 90% HRR, compared to the other exercise intensities. There was no difference in timing responses at 90% HRR during competitive trials, irrespective of whether exercise intensity was increasing or decreasing. This study suggests that anticipation timing performance is negatively affected when physiological arousal and cognitive anxiety are high.

Does Physical Loading Affect The Speed and Accuracy of Tactical Decision-Making in Elite Junior Soccer Players?

PubMed

Frýbort, Pavel; Kokštejn, Jakub; Musálek, Martin; Süss, Vladimír

2016-06-01

A soccer player's capability to control and manage his behaviour in a game situation is a prerequisite, reflecting not only swift and accurate tactical decision-making, but also prompt implementation of a motor task during intermittent exercise conditions. The purpose of this study was to analyse the relationship between varying exercise intensity and the visual-motor response time and the accuracy of motor response in an offensive game situation in soccer. The participants (n = 42) were male, semi-professional, soccer players (M age 18.0 ± 0.9 years) and trained five times a week. Each player performed four different modes of exercise intensity on the treadmill (motor inactivity, aerobic, intermittent and anaerobic activity). After the end of each exercise, visual-motor response time and accuracy of motor response were assessed. Players' motion was captured by digital video camera. ANOVA indicated no significant difference (p = 0.090) in the accuracy of motor response between the four exercise intensity modes. Practical significance (Z-test = 0.31) was found in visual-motor response time between exercise with dominant involvement of aerobic metabolism, and intense intermittent exercise. A medium size effect (Z-test = 0.34) was also found in visual-motor response time between exercise with dominant involvement of aerobic metabolism and exercise with dominant involvement of anaerobic metabolism, which was confirmed by ANOVA (897.02 ± 57.46 vs. 940.95 ± 71.14; p = 0.002). The results showed that different modes of exercise intensity do not adversely affect the accuracy of motor responses; however, high-intensity exercise has a negative effect on visual-motor response time in comparison to moderate intensity exercise. Key pointsDifferent exercise intensity modes did not affect the accuracy of motor response.Anaerobic, highly intensive short-term exercise significantly decreased the visual-motor response time in comparison with aerobic exercise.Further research should focus on the assessment of VMRT from a player's real - field position view rather than a perspective view.

Metabolic effects of exercise on childhood obesity: a current view

PubMed Central

Paes, Santiago Tavares; Marins, João Carlos Bouzas; Andreazzi, Ana Eliza

2015-01-01

OBJECTIVE: To review the current literature concerning the effects of physical exercise on several metabolic variables related to childhood obesity. DATA SOURCE: A search was performed in Pubmed/MEDLINE and Web of Science databases. The keywords used were as follows: Obesity, Children Obesity, Childhood Obesity, Exercise and Physical Activity. The online search was based on studies published in English, from April 2010 to December 2013. DATA SYNTHESIS: Search queries returned 88,393 studies based on the aforementioned keywords; 4,561 studies were selected by crossing chosen keywords. After applying inclusion criteria, four studies were selected from 182 eligible titles. Most studies found that aerobic and resistance training improves body composition, lipid profile and metabolic and inflammatory status of obese children and adolescents; however, the magnitude of these effects is associated with the type, intensity and duration of practice. CONCLUSIONS: Regardless of the type, physical exercise promotes positive adaptations to childhood obesity, mainly acting to restore cellular and cardiovascular homeostasis, to improve body composition, and to activate metabolism; therefore, physical exercise acts as a co-factor in fighting obesity. PMID:25662015

Treatment Approaches for Interoceptive Dysfunctions in Drug Addiction

PubMed Central

Paulus, Martin P.; Stewart, Jennifer L.; Haase, Lori

2013-01-01

There is emerging evidence that individuals with drug addiction have dysfunctions in brain systems that are important for interoceptive processing, which include, among others, the insular and the anterior cingulate cortices. These individuals may not be expending sufficient neural resources to process perturbations of the interoceptive state but may exert over-activation of these systems when processing drug-related stimuli. As a consequence, insufficient detection and processing of interoceptive state changes may result in inadequate anticipation and preparation to adapt to environmental challenges, e.g., adapt to abstinence in the presence of withdrawal symptoms. Here, we integrate interoceptive dysfunction in drug-addicted individuals, with the neural basis for meditation and exercise to develop a heuristic to target the interoceptive system as potential treatments for drug addiction. First, it is suggested that mindfulness-based approaches can modulate both interoceptive function and insular activation patterns. Second, there is an emerging literature showing that the regulation of physical exercise in the brain involves the insula and anterior cingulate cortex and that intense physical exercise is associated with a insula changes that may provide a window to attenuate the increased interoceptive response to drug-related stimuli. It is concluded that the conceptual framework of interoceptive dysfunctions in drug addiction and the experimental findings in meditation and exercise provide a useful approach to develop new interventions for drug addiction. PMID:24151471

Treatment approaches for interoceptive dysfunctions in drug addiction.

PubMed

Paulus, Martin P; Stewart, Jennifer L; Haase, Lori

2013-10-18

There is emerging evidence that individuals with drug addiction have dysfunctions in brain systems that are important for interoceptive processing, which include, among others, the insular and the anterior cingulate cortices. These individuals may not be expending sufficient neural resources to process perturbations of the interoceptive state but may exert over-activation of these systems when processing drug-related stimuli. As a consequence, insufficient detection and processing of interoceptive state changes may result in inadequate anticipation and preparation to adapt to environmental challenges, e.g., adapt to abstinence in the presence of withdrawal symptoms. Here, we integrate interoceptive dysfunction in drug-addicted individuals, with the neural basis for meditation and exercise to develop a heuristic to target the interoceptive system as potential treatments for drug addiction. First, it is suggested that mindfulness-based approaches can modulate both interoceptive function and insular activation patterns. Second, there is an emerging literature showing that the regulation of physical exercise in the brain involves the insula and anterior cingulate cortex and that intense physical exercise is associated with a insula changes that may provide a window to attenuate the increased interoceptive response to drug-related stimuli. It is concluded that the conceptual framework of interoceptive dysfunctions in drug addiction and the experimental findings in meditation and exercise provide a useful approach to develop new interventions for drug addiction.

Chronic β2 -adrenoceptor agonist treatment alters muscle proteome and functional adaptations induced by high intensity training in young men.

PubMed

Hostrup, Morten; Onslev, Johan; Jacobson, Glenn A; Wilson, Richard; Bangsbo, Jens

2018-01-15

While several studies have investigated the effects of exercise training in human skeletal muscle and the chronic effect of β 2 -agonist treatment in rodent muscle, their effects on muscle proteome signature with related functional measures in humans are still incompletely understood. Herein we show that daily β 2 -agonist treatment attenuates training-induced enhancements in exercise performance and maximal oxygen consumption, and alters muscle proteome signature and phenotype in trained young men. Daily β 2 -agonist treatment abolished several of the training-induced enhancements in muscle oxidative capacity and caused a repression of muscle metabolic pathways; furthermore, β 2 -agonist treatment induced a slow-to-fast twitch muscle phenotype transition. The present study indicates that chronic β 2 -agonist treatment confounds the positive effect of high intensity training on exercise performance and oxidative capacity, which is of interest for the large proportion of persons using inhaled β 2 -agonists on a daily basis, including athletes. Although the effects of training have been studied for decades, data on muscle proteome signature remodelling induced by high intensity training in relation to functional changes in humans remains incomplete. Likewise, β 2 -agonists are frequently used to counteract exercise-induced bronchoconstriction, but the effects β 2 -agonist treatment on muscle remodelling and adaptations to training are unknown. In a placebo-controlled parallel study, we randomly assigned 21 trained men to 4 weeks of high intensity training with (HIT+β 2 A) or without (HIT) daily inhalation of β 2 -agonist (terbutaline, 4 mg dose -1 ). Of 486 proteins identified by mass-spectrometry proteomics of muscle biopsies sampled before and after the intervention, 32 and 85 were changing (false discovery rate (FDR) ≤5%) with the intervention in HIT and HIT+β 2 A, respectively. Proteome signature changes were different in HIT and HIT+β 2 A (P = 0.005), wherein β 2 -agonist caused a repression of 25 proteins in HIT+β 2 A compared to HIT, and an upregulation of 7 proteins compared to HIT. β 2 -Agonist repressed or even downregulated training-induced enrichment of pathways related to oxidative phosphorylation and glycogen metabolism, but upregulated pathways related to histone trimethylation and the nucleosome. Muscle contractile phenotype changed differently in HIT and HIT+β 2 A (P ≤ 0.001), with a fast-to-slow twitch transition in HIT and a slow-to-fast twitch transition in HIT+β 2 A. β 2 -Agonist attenuated training-induced enhancements in maximal oxygen consumption (P ≤ 0.01) and exercise performance (6.1 vs. 11.6%, P ≤ 0.05) in HIT+β 2 A compared to HIT. These findings indicate that daily β 2 -agonist treatment attenuates the beneficial effects of high intensity training on exercise performance and oxidative capacity, and causes remodelling of muscle proteome signature towards a fast-twitch phenotype. © 2017 The Authors. The Journal of Physiology © 2017 The Physiological Society.

Effects of exercise intensity and duration on nocturnal heart rate variability and sleep quality.

PubMed

Myllymäki, Tero; Rusko, Heikki; Syväoja, Heidi; Juuti, Tanja; Kinnunen, Marja-Liisa; Kyröläinen, Heikki

2012-03-01

Acute physical exercise may affect cardiac autonomic modulation hours or even days during the recovery phase. Although sleep is an essential recovery period, the information on nocturnal autonomic modulation indicated by heart rate variability (HRV) after different exercises is mostly lacking. Therefore, this study investigated the effects of exercise intensity and duration on nocturnal HR, HRV, HR, and HRV-based relaxation, as well as on actigraphic and subjective sleep quality. Fourteen healthy male subjects (age 36 ± 4 years, maximal oxygen uptake 49 ± 4 ml/kg/min) performed five different running exercises on separate occasions starting at 6 p.m. with HR guidance at home. The effect of intensity was studied with 30 min of exercises at intensities corresponding to HR level at 45% (easy), 60% (moderate) and 75% (vigorous) of their maximal oxygen uptake. The effect of duration was studied with 30, 60, and 90 min of moderate exercises. Increased exercise intensity elevated nocturnal HR compared to control day (p < 0.001), but it did not affect nocturnal HRV. Nocturnal HR was greater after the day with 90- than 30- or 60-min exercises (p < 0.01) or control day (p < 0.001). Nocturnal HRV was lower after the 90-min exercise day compared to control day (p < 0.01). Neither exercise intensity nor duration had any impact on actigraphic or subjective sleep quality. The results suggest that increased exercise intensity and/or duration cause delayed recovery of nocturnal cardiac autonomic modulation, although long exercise duration was needed to induce changes in nocturnal HRV. Increased exercise intensity or duration does not seem to disrupt sleep quality.

The effect of exercise intensity on postresistance exercise hypotension in trained men.

PubMed

Duncan, Michael J; Birch, Samantha L; Oxford, Samuel W

2014-06-01

The occurrence of postresistance exercise hypotension (PEH) after resistance exercise remains unknown. This study examined blood pressure and heart rate (HR) responses to an acute bout of low- and high-intensity resistance exercise, matched for total work, in trained males. Sixteen resistance-trained males (23.1 ± 5.9 years) performed an acute bout of low- (40% of 1 repetition maximum [1RM]) and high-intensity resistance exercise (80% 1RM), matched for total work, separated by 7 days and performed in a counterbalanced order. Systolic blood pressure (SBP) and diastolic blood pressure (DBP), mean arterial pressure (MAP), and HR were assessed before exercise, after completion of each exercise resistance exercise (3 sets of back squat, bench press, and deadlift) and every 10 minutes after resistance exercise for a period of 60 minutes. Results indicated a significant intensity × time interaction for SBP (p = 0.034, partial η(2) = 0.122) and MAP (p = 0.047, partial η(2) = 0.116) whereby SBP and MAP at 50-minute recovery and 60-minute recovery were significantly lower after high-intensity exercise (p = 0.01 for SBP and p = 0.05 for MAP in both cases) compared with low-intensity exercise. There were no significant main effects or interactions in regard to DBP (all p > 0.05). Heart rate data indicated a significant main effect for time (F(9, 135) = 2.479, p = 0.0001, partial η(2) = 0.344). Post hoc multiple comparisons indicated that HR was significantly higher after squat, bench press, and deadlift exercise compared with resting HR and HR at 40-, 50-, and 60-minute recovery (all p = 0.03). The present findings suggest that an acute bout of high intensity, but not low intensity, resistance exercise using compound movements can promote PEH in trained men.

Aerobic exercise prevents age-dependent cognitive decline and reduces anxiety-related behaviors in middle-aged and old rats.

PubMed

Pietrelli, A; Lopez-Costa, J; Goñi, R; Brusco, A; Basso, N

2012-01-27

Recent research involving human and animals has shown that aerobic exercise of moderate intensity produces the greatest benefit on brain health and behavior. In this study we investigated the effects on cognitive function and anxiety-related behavior in rats at different ages of aerobic exercise, performed regularly throughout life. We designed an aerobic training program with the treadmill running following the basic principles of human training, and assuming that rats have the same physiological adaptations. The intensity was gradually adjusted to the fitness level and age, and maintained at 60-70% of maximum oxygen consumption (max.VO(2)). In middle age (8 months) and old age (18 months), we studied the cognitive response with the radial maze (RM), and anxiety-related behaviors with the open field (OF) and the elevated plus maze (EPM). Aerobically trained (AT) rats had a higher cognitive performance measured in the RM, showing that exercise had a cumulative and amplifier effect on memory and learning. The analysis of age and exercise revealed that the effects of aerobic exercise were modulated by age. Middle-aged AT rats were the most successful animals; however, the old AT rats met the criteria more often than the middle-aged sedentary controls (SC), indicating that exercise could reverse the negative effects of sedentary life, partially restore the cognitive function, and protect against the deleterious effects of aging. The results in the OF and EPM showed a significant decrease in key indicators of anxiety, revealing that age affected most of the analyzed variables, and that exercise had a prominent anxiolytic effect, particularly strong in old age. In conclusion, our results indicated that regular and chronic aerobic exercise has time and dose-dependent, neuroprotective and restorative effects on physiological brain aging, and reduces anxiety-related behaviors. Copyright © 2011 IBRO. Published by Elsevier Ltd. All rights reserved.

Satellite cell response to concurrent resistance exercise and high-intensity interval training in sedentary, overweight/obese, middle-aged individuals.

PubMed

Pugh, Jamie K; Faulkner, Steve H; Turner, Mark C; Nimmo, Myra A

2018-02-01

Sarcopenia can begin from the 4-5th decade of life and is exacerbated by obesity and inactivity. A combination of resistance exercise (RE) and endurance exercise is recommended to combat rising obesity and inactivity levels. However, work continues to elucidate whether interference in adaptive outcomes occur when RE and endurance exercise are performed concurrently. This study examined whether a single bout of concurrent RE and high-intensity interval training (HIIT) alters the satellite cell response following exercise compared to RE alone. Eight sedentary, overweight/obese, middle-aged individuals performed RE only (8 × 8 leg extensions at 70% 1RM), or RE + HIIT (10 × 1 min at 90% HR max on a cycle ergometer). Muscle biopsies were collected from the vastus lateralis before and 96 h after the RE component to determine muscle fiber type-specific total (Pax7 + cells) and active (MyoD + cells) satellite cell number using immunofluorescence microscopy. Type-I-specific Pax7 + (P = 0.001) cell number increased after both exercise trials. Type-I-specific MyoD + (P = 0.001) cell number increased after RE only. However, an elevated baseline value in RE + HIIT compared to RE (P = 0.046) was observed, with no differences between exercise trials at 96 h (P = 0.21). Type-II-specific Pax7 + and MyoD + cell number remained unchanged after both exercise trials (all P ≥ 0.13). Combining a HIIT session after a single bout of RE does not interfere with the increase in type-I-specific total, and possibly active, satellite cell number, compared to RE only. Concurrent RE + HIIT may offer a time-efficient way to maximise the physiological benefits from a single bout of exercise in sedentary, overweight/obese, middle-aged individuals.

Applied physiology of triathlon.

PubMed

O'Toole, M L; Douglas, P S

1995-04-01

The triathlon is a 3-event endurance sport in which athletes compete sequentially in swimming, cycling and running. The primary determinant of success is the ability to sustain a high rate of energy expenditure for prolonged periods of time. Exercise training-induced physiological adaptations in virtually all systems of the body allow the athlete to accomplish this. Aerobic capacity (measured as maximal oxygen uptake, VO2max), economy of motion (submaximal VO2) and fractional utilisation of maximal capacity (%VO2max) reflect the integrated responses of these physiological adaptations. Numerous studies have reported relatively high mean VO2max values for various groups of triathletes that are comparable to those reported for athletes in single-event endurance sports and clearly above those reported for untrained individuals. In shorter distance triathlons and in studies using recreational (rather than elite) triathletes, VO2max is related to performance in the corresponding event of the triathlon (e.g. tethered swimming VO2max with swim time). In longer events and with more elite triathletes, VO2max correlates less well with performance. The physiological adaptations that correspond to and facilitate improved VO2max occur centrally in the cardiovascular system, centred on increased maximal cardiac output, and peripherally in the metabolic systems, centred around increased arterio-venous O2 (a-v O2) difference. While a high VO2max in individuals is clearly of importance to triathlon performance, energy output must be sustained for long periods of time, making economy of motion also very important. Studies suggests that competitive swimmers have better swimming economy than triathletes. However, since many triathletes have previously been competitive swimmers this finding is questionable. The finding suggests that triathletes from nonswimming backgrounds would benefit from improving swimming technique rather than concentrating training workouts solely on distance. In cycling and running, comparison studies have not been done. Economy of motion in swimming, cycling and running have all been found to be correlated with comparable event performance. Training to improve swimming economy can be done without prior exercise, but training to improve swimming economy can be done without prior exercise, but training to improve cycling and running economy should take the multimode nature of a triathlon into consideration. That is, swimming should precede cycling economy training, and cycling should precede running economy training. Cardiovascular, metabolic and neuromuscular adaptations are the main physiological correlates of improved movement economy. Since exercise-induced stress on most physiological systems is based on relative, rather than absolute, exercise intensity, training and racing intensities are frequently quantified as a percentage of maximal capacity of %VO2max.(ABSTRACT TRUNCATED AT 400 WORDS)

Objective and subjective measures of exercise intensity during thermo-neutral and hot yoga.

PubMed

Boyd, Corinne N; Lannan, Stephanie M; Zuhl, Micah N; Mora-Rodriguez, Ricardo; Nelson, Rachael K

2018-04-01

While hot yoga has gained enormous popularity in recent years, owing in part to increased environmental challenge associated with exercise in the heat, it is not clear whether hot yoga is more vigorous than thermo-neutral yoga. Therefore, the aim of this study was to determine objective and subjective measures of exercise intensity during constant intensity yoga in a hot and thermo-neutral environment. Using a randomized, crossover design, 14 participants completed 2 identical ∼20-min yoga sessions in a hot (35.3 ± 0.8 °C; humidity: 20.5% ± 1.4%) and thermo-neutral (22.1 ± 0.2 °C; humidity: 27.8% ± 1.6%) environment. Oxygen consumption and heart rate (HR) were recorded as objective measures (percentage of maximal oxygen consumption and percentage of maximal HR (%HRmax)) and rating of perceived exertion (RPE) was recorded as a subjective measure of exercise intensity. There was no difference in exercise intensity based on percentage of maximal oxygen consumption during hot versus thermo-neutral yoga (30.9% ± 2.3% vs. 30.5% ± 1.8%, p = 0.68). However, exercise intensity was significantly higher during hot versus thermo-neutral yoga based on %HRmax (67.0% ± 2.3% vs. 60.8% ± 1.9%, p = 0.01) and RPE (12 ± 1 vs. 11 ± 1, p = 0.04). According to established exercise intensities, hot yoga was classified as light-intensity exercise based on percentage of maximal oxygen consumption but moderate-intensity exercise based on %HRmax and RPE while thermo-neutral yoga was classified as light-intensity exercise based on percentage of maximal oxygen uptake, %HRmax, and RPE. Despite the added hemodynamic stress and perception that yoga is more strenuous in a hot environment, we observed similar oxygen consumption during hot versus thermo-neutral yoga, classifying both exercise modalities as light-intensity exercise.

Effects of fasted vs fed-state exercise on performance and post-exercise metabolism: A systematic review and meta-analysis.

PubMed

Aird, T P; Davies, R W; Carson, B P

2018-05-01

The effects of nutrition on exercise metabolism and performance remain an important topic among sports scientists, clinical, and athletic populations. Recently, fasted exercise has garnered interest as a beneficial stimulus which induces superior metabolic adaptations to fed exercise in key peripheral tissues. Conversely, pre-exercise feeding augments exercise performance compared with fasting conditions. Given these seemingly divergent effects on performance and metabolism, an appraisal of the literature is warranted. This review determined the effects of fasting vs pre-exercise feeding on continuous aerobic and anaerobic or intermittent exercise performance, and post-exercise metabolic adaptations. A search was performed using the MEDLINE and PubMed search engines. The literature search identified 46 studies meeting the relevant inclusion criteria. The Delphi list was used to assess study quality. A meta-analysis and meta-regression were performed where appropriate. Findings indicated that pre-exercise feeding enhanced prolonged (P = .012), but not shorter duration aerobic exercise performance (P = .687). Fasted exercise increased post-exercise circulating FFAs (P = .023) compared to fed exercise. It is evidenced that pre-exercise feeding blunted signaling in skeletal muscle and adipose tissue implicated in regulating components of metabolism, including mitochondrial adaptation and substrate utilization. This review's findings support the hypothesis that the fasted and fed conditions can divergently influence exercise metabolism and performance. Pre-exercise feeding bolsters prolonged aerobic performance, while seminal evidence highlights potential beneficial metabolic adaptations that fasted exercise may induce in peripheral tissues. However, further research is required to fully elucidate the acute and chronic physiological adaptations to fasted vs fed exercise. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Decline in Executive Control during Acute Bouts of Exercise as a Function of Exercise Intensity and Fitness Level

ERIC Educational Resources Information Center

Labelle, Veronique; Bosquet, Laurent; Mekary, Said; Bherer, Louis

2013-01-01

Studies on the effects of acute bouts of cardiovascular exercise on cognitive performances show contradictory findings due to methodological differences (e.g., exercise intensity, cognitive function assessed, participants' aerobic fitness level, etc.). The present study assessed the acute effect of exercise intensity on cognition while controlling…

Study in Parkinson Disease of Exercise (SPARX): Translating high-intensity exercise from animals to humans

PubMed Central

Moore, Charity G.; Schenkman, Margaret; Kohrt, Wendy M.; Delitto, Anthony; Hall, Deborah A.; Corcos, Daniel

2013-01-01

A burgeoning literature suggests that exercise has a therapeutic benefit in persons with Parkinson disease (PD) and in animal models of PD, especially when animals exercise at high intensity. If exercise is to be prescribed as “first-line” or “add-on” therapy in patients with PD, we must demonstrate its efficacy and dose-response effects through testing phases similar to those used in the testing of pharmacologic agents. The SPARX Trial is a multicenter, randomized, controlled, single-blinded, Phase II study that we designed to test the feasibility of using high-intensity exercise to modify symptoms of PD and to simultaneously test the nonfutility of achieving a prespecified change in patients’ motor scores on the Unified Parkinson Disease Rating Scale (UPDRS). The trial began in May 2102 and is in the process of screening, enrolling, and randomly assigning 126 patients with early-stage PD to 1 of 3 groups: usual care (wait-listed controls), moderate-intensity exercise (4 days/week at 60%–65% maximal heart rate [HRmax]), or high-intensity exercise (4 days/week at 80%–85% HRmax). At 6-month follow-up, the trial is randomly reassigning usual care participants to a moderate-intensity or high-intensity exercise group for the remaining 6 months. The goals of the Phase II trial are to determine if participants can exercise at moderate and high intensities; to determine if either exercise yields benefits consistent with meaningful clinical change (nonfutility); and to document safety and attrition. The advantage of using a non-futility approach allows us to efficiently determine if moderate- or high-intensity exercise warrants further large-scale investigation in PD. PMID:23770108

High-intensity exercise interventions in cancer survivors: a systematic review exploring the impact on health outcomes.

PubMed

Toohey, Kellie; Pumpa, Kate; McKune, Andrew; Cooke, Julie; Semple, Stuart

2018-01-01

There is an increasing body of evidence underpinning high-intensity exercise as an effective and time-efficient intervention for improving health in cancer survivors. The aim of this study was to, (1) evaluate the efficacy and (2) the safety of high-intensity exercise interventions in improving selected health outcomes in cancer survivors. Design Systematic review. Data sources Google Scholar and EBSCO, CINAHL Plus, Computers and Applied Sciences Complete, Health Source-Consumer Edition, Health Source: Nursing/Academic Edition, MEDLINE, Web of Science and SPORTDiscuss from inception up until August 2017. Eligibility criteria Randomized controlled trials of high-intensity exercise interventions in cancer survivors (all cancer types) with health-related outcome measures. The guidelines adopted for this review were the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA). The search returned 447 articles, of which nine articles (n = 531 participants mean, age 58 ± 9.5 years) met the eligibility criteria. Exercise interventions of between 4 and 18 weeks consisting of high-intensity interval bouts of up to 4-min were compared with a continuous moderate intensity (CMIT) intervention or a control group. High-intensity exercise interventions elicited significant improvements in VO 2 max, strength, body mass, body fat and hip and waist circumference compared with CMIT and/or control groups. The studies reviewed showed low risk in participating in supervised high-intensity exercise interventions. Mixed mode high-intensity interventions which included both aerobic and resistance exercises were most effective improving the aerobic fitness levels of cancer survivors by 12.45-21.35%, from baseline to post-intervention. High-intensity exercise interventions improved physical and physiological health-related outcome measures such as cardiovascular fitness and strength in cancer survivors. Given that high-intensity exercise sessions require a shorter time commitment, it may be a useful modality to improve health outcomes in those who are time poor. The risk of adverse events associated with high-intensity exercise was low.

Comparable Neutrophil Responses for Arm and Intensity-matched Leg Exercise.

PubMed

Leicht, Christof A; Goosey-Tolfrey, Victoria L; Bishop, Nicolette C

2017-08-01

Arm exercise is performed at lower absolute intensities than lower body exercise. This may impact on intensity-dependent neutrophil responses, and it is unknown whether individuals restricted to arm exercise experience the same changes in the neutrophil response as found for lower body exercise. Therefore, we aimed to investigate the importance of exercise modality and relative exercise intensity on the neutrophil response. Twelve moderately trained men performed three 45-min constant load exercise trials after determination of peak oxygen uptake for arm exercise (V˙O2peak arms) and cycling (V˙O2peak legs): 1) arm cranking exercise at 60% V˙O2peak arms, 2) moderate cycling at 60% V˙O2peak legs, and 3) easy cycling at 60% V˙O2peak arms. Neutrophil numbers in the circulation increased for all exercise trials, but were significantly lower for easy cycling when compared with arm exercise (P = 0.009), mirroring the blunted increase in HR and epinephrine during easy cycling. For all trials, exercising HR explained some of the variation of the neutrophil number 2 h postexercise (R = 0.51-0.69), epinephrine explaining less of this variation (R = 0.21-0.34). The number of neutrophils expressing CXCR2 decreased in the recovery from exercise in all trials (P < 0.05). Arm and leg exercise elicits the same neutrophil response when performed at the same relative intensity, implying that populations restricted to arm exercise might achieve a similar exercise induced neutrophil response as those performing lower body exercise. A likely explanation for this is the higher sympathetic activation and cardiac output for arm and relative intensity-matched leg exercise when compared with easy cycling, which is partly reflected in HR. This study further shows that the downregulation of CXCR2 may be implicated in exercise-induced neutrophilia.

Effects of aerobic training intensity on resting, exercise and post-exercise blood pressure, heart rate and heart-rate variability.

PubMed

Cornelissen, V A; Verheyden, B; Aubert, A E; Fagard, R H

2010-03-01

We aimed to investigate the effects of endurance training intensity (1) on systolic blood pressure (SBP) and heart rate (HR) at rest before exercise, and during and after a maximal exercise test; and (2) on measures of HR variability at rest before exercise and during recovery from the exercise test, in at least 55-year-old healthy sedentary men and women. A randomized crossover study comprising three 10-week periods was performed. In the first and third period, participants exercised at lower or higher intensity (33% or 66% of HR reserve) in random order, with a sedentary period in between. Training programmes were identical except for intensity, and were performed under supervision thrice for 1 h per week. The results show that in the three conditions, that is, at rest before exercise, during exercise and during recovery, we found endurance training at lower and higher intensity to reduce SBP significantly (P<0.05) and to a similar extent. Further, SBP during recovery was, on average, not lower than at rest before exercise, and chronic endurance training did not affect the response of SBP after an acute bout of exercise. The effect of training on HR at rest, during exercise and recovery was more pronounced (P<0.05) with higher intensity. Finally, endurance training had no significant effect on sympathovagal balance. In conclusion, in participants at higher age, both training programmes exert similar effects on SBP at rest, during exercise and during post-exercise recovery, whereas the effects on HR are more pronounced after higher intensity training.

High-Intensity Intermittent Exercise and Autonomic Modulation: Effects of Different Volume Sessions.

PubMed

Castrillón, Carlos Iván Mesa; Miranda, Rodolfo Augusto Travagin; Cabral-Santos, Carolina; Vanzella, Lais Manata; Rodrigues, Bruno; Vanderlei, Luiz Carlos Marques; Lira, Fábio Santos; Campos, Eduardo Zapaterra

2017-06-01

The aim of this study was to compare heart rate variability (HRV) recovery after 2 sessions of high-intensity intermittent exercise at different volumes (1.25 km [HIIE 1.25 ] and 2.5 km [HIIE 2.5 ]). 13 participants determined their maximal aerobic speed (MAS) and completed 2 HIIE (1:1 at 100% MAS) trials. The heart rate was recorded before and after each session. HRV indicators were calculated according to time (RMSSD and SDNN) and frequency (LF, HF and LF/HF ratio) domains. SDNN and RMSSD presented effect of test (F=20.97; p<0.01 and F=21.00; p<0.01, respectively) and moment (F=6.76; p<0.01 and F=12.30; p<0.01, respectively), without interaction. Even though we did not find an interaction effect for any HRV variables, the HIIE 2.5 presented a delay of only 5 min in HRV recovery, when compared to HIIE 1.25 . However, the effects of the test (SDNN, RMSSD, LF-log, and HF-log) indicate higher autonomic stress during the entire recovery period. These findings may indicate that exercise volume interferes with HRV recovery. If so, physically active subjects may choose a lower volume exercise (i. e., HIIE 1.25 ) in order to promote similar physical fitness adaptations with lower loading on autonomic modulation. © Georg Thieme Verlag KG Stuttgart · New York.

Time-Course Changes of Oxidative Stress Response to High-Intensity Discontinuous Training versus Moderate-Intensity Continuous Training in Masters Runners

PubMed Central

Vezzoli, Alessandra; Pugliese, Lorenzo; Marzorati, Mauro; Serpiello, Fabio Rubens; La Torre, Antonio; Porcelli, Simone

2014-01-01

Beneficial systemic effects of regular physical exercise have been demonstrated to reduce risks of a number of age-related disorders. Antioxidant capacity adaptations are amongst these fundamental changes in response to exercise training. However, it has been claimed that acute physical exercise performed at high intensity (>60% of maximal oxygen uptake) may result in oxidative stress, due to reactive oxygen species being generated excessively by enhanced oxygen consumption. The aim of this study was to evaluate the effect of high-intensity discontinuous training (HIDT), characterized by repeated variations of intensity and changes of redox potential, on oxidative damage. Twenty long-distance masters runners (age 47.8±7.8 yr) on the basis of the individual values of gas exchange threshold were assigned to a different 8-weeks training program: continuous moderate-intensity training (MOD, n = 10) or HIDT (n = 10). In both groups before (PRE) and after (POST) training we examined the following oxidative damage markers: thiobarbituric acid reactive substances (TBARS) as marker of lipid peroxidation; protein carbonyls (PC) as marker of protein oxidation; 8-hydroxy-2-deoxy-guanosine (8-OH-dG) as a biomarker of DNA base modifications; and total antioxidant capacity (TAC) as indicator of the overall antioxidant system. Training induced a significant (p<0.05) decrease in resting plasma TBARS concentration in both MOD (7.53±0.30 and 6.46±0.27 µM, PRE and POST respectively) and HIDT (7.21±0.32 and 5.85±0.46 µM, PRE and POST respectively). Resting urinary 8-OH-dG levels were significantly decreased in both MOD (5.50±0.66 and 4.16±0.40 ng mg−1creatinine, PRE and POST respectively) and HIDT (4.52±0.50 and 3.18±0.34 ng mg−1creatinine, PRE and POST respectively). Training both in MOD and HIDT did not significantly modify plasma levels of PC. Resting plasma TAC was reduced in MOD while no significant changes were observed in HIDT. In conclusion, these results suggest that in masters runners high-intensity discontinuous does not cause higher level of exercise-induced oxidative stress than continuous moderate-intensity training, inducing similar beneficial effects on redox homeostasis. PMID:24498121

Cardiac Autonomic Responses during Exercise and Post-exercise Recovery Using Heart Rate Variability and Systolic Time Intervals-A Review.

PubMed

Michael, Scott; Graham, Kenneth S; Davis, Glen M

2017-01-01

Cardiac parasympathetic activity may be non-invasively investigated using heart rate variability (HRV), although HRV is not widely accepted to reflect sympathetic activity. Instead, cardiac sympathetic activity may be investigated using systolic time intervals (STI), such as the pre-ejection period. Although these autonomic indices are typically measured during rest, the "reactivity hypothesis" suggests that investigating responses to a stressor (e.g., exercise) may be a valuable monitoring approach in clinical and high-performance settings. However, when interpreting these indices it is important to consider how the exercise dose itself (i.e., intensity, duration, and modality) may influence the response. Therefore, the purpose of this investigation was to review the literature regarding how the exercise dosage influences these autonomic indices during exercise and acute post-exercise recovery. There are substantial methodological variations throughout the literature regarding HRV responses to exercise, in terms of exercise protocols and HRV analysis techniques. Exercise intensity is the primary factor influencing HRV, with a greater intensity eliciting a lower HRV during exercise up to moderate-high intensity, with minimal change observed as intensity is increased further. Post-exercise, a greater preceding intensity is associated with a slower HRV recovery, although the dose-response remains unclear. A longer exercise duration has been reported to elicit a lower HRV only during low-moderate intensity and when accompanied by cardiovascular drift, while a small number of studies have reported conflicting results regarding whether a longer duration delays HRV recovery. "Modality" has been defined multiple ways, with limited evidence suggesting exercise of a greater muscle mass and/or energy expenditure may delay HRV recovery. STI responses during exercise and recovery have seldom been reported, although limited data suggests that intensity is a key determining factor. Concurrent monitoring of HRV and STI may be a valuable non-invasive approach to investigate autonomic stress reactivity; however, this integrative approach has not yet been applied with regards to exercise stressors.

Cardiac Autonomic Responses during Exercise and Post-exercise Recovery Using Heart Rate Variability and Systolic Time Intervals—A Review

PubMed Central

Michael, Scott; Graham, Kenneth S.; Davis, Glen M.

2017-01-01

Cardiac parasympathetic activity may be non-invasively investigated using heart rate variability (HRV), although HRV is not widely accepted to reflect sympathetic activity. Instead, cardiac sympathetic activity may be investigated using systolic time intervals (STI), such as the pre-ejection period. Although these autonomic indices are typically measured during rest, the “reactivity hypothesis” suggests that investigating responses to a stressor (e.g., exercise) may be a valuable monitoring approach in clinical and high-performance settings. However, when interpreting these indices it is important to consider how the exercise dose itself (i.e., intensity, duration, and modality) may influence the response. Therefore, the purpose of this investigation was to review the literature regarding how the exercise dosage influences these autonomic indices during exercise and acute post-exercise recovery. There are substantial methodological variations throughout the literature regarding HRV responses to exercise, in terms of exercise protocols and HRV analysis techniques. Exercise intensity is the primary factor influencing HRV, with a greater intensity eliciting a lower HRV during exercise up to moderate-high intensity, with minimal change observed as intensity is increased further. Post-exercise, a greater preceding intensity is associated with a slower HRV recovery, although the dose-response remains unclear. A longer exercise duration has been reported to elicit a lower HRV only during low-moderate intensity and when accompanied by cardiovascular drift, while a small number of studies have reported conflicting results regarding whether a longer duration delays HRV recovery. “Modality” has been defined multiple ways, with limited evidence suggesting exercise of a greater muscle mass and/or energy expenditure may delay HRV recovery. STI responses during exercise and recovery have seldom been reported, although limited data suggests that intensity is a key determining factor. Concurrent monitoring of HRV and STI may be a valuable non-invasive approach to investigate autonomic stress reactivity; however, this integrative approach has not yet been applied with regards to exercise stressors. PMID:28611675

Principles of exercise physiology: responses to acute exercise and long-term adaptations to training.

PubMed

Rivera-Brown, Anita M; Frontera, Walter R

2012-11-01

Physical activity and fitness are associated with a lower prevalence of chronic diseases, such as heart disease, cancer, high blood pressure, and diabetes. This review discusses the body's response to an acute bout of exercise and long-term physiological adaptations to exercise training with an emphasis on endurance exercise. An overview is provided of skeletal muscle actions, muscle fiber types, and the major metabolic pathways involved in energy production. The importance of adequate fluid intake during exercise sessions to prevent impairments induced by dehydration on endurance exercise, muscular power, and strength is discussed. Physiological adaptations that result from regular exercise training such as increases in cardiorespiratory capacity and strength are mentioned. The review emphasizes the cardiovascular and metabolic adaptations that lead to improvements in maximal oxygen capacity. Copyright © 2012 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

Individual Responses to Completion of Short-Term and Chronic Interval Training: A Retrospective Study

PubMed Central

Astorino, Todd A.; Schubert, Matthew M.

2014-01-01

Alterations in maximal oxygen uptake (VO2max), heart rate (HR), and fat oxidation occur in response to chronic endurance training. However, many studies report frequent incidence of “non-responders” who do not adapt to continuous moderate exercise. Whether this is the case in response to high intensity interval training (HIT), which elicits similar adaptations as endurance training, is unknown. The aim of this retrospective study was to examine individual responses to two paradigms of interval training. In the first study (study 1), twenty active men and women (age and baseline VO2max = 24.0±4.6 yr and 42.8±4.8 mL/kg/min) performed 6 d of sprint interval training (SIT) consisting of 4–6 Wingate tests per day, while in a separate study (study 2), 20 sedentary women (age and baseline VO2max = 23.7±6.2 yr and 30.0±4.9 mL/kg/min) performed 12 wk of high-volume HIT at workloads ranging from 60–90% maximal workload. Individual changes in VO2max, HR, and fat oxidation were examined in each study, and multiple regression analysis was used to identify predictors of training adaptations to SIT and HIT. Data showed high frequency of increased VO2max (95%) and attenuated exercise HR (85%) in response to HIT, and low frequency of response for VO2max (65%) and exercise HR (55%) via SIT. Frequency of improved fat oxidation was similar (60–65%) across regimens. Only one participant across both interventions showed non-response for all variables. Baseline values of VO2max, exercise HR, respiratory exchange ratio, and body fat were significant predictors of adaptations to interval training. Frequency of positive responses to interval training seems to be greater in response to prolonged, higher volume interval training compared to similar durations of endurance training. PMID:24847797

Cardiac damage in athlete's heart: When the "supernormal" heart fails!

PubMed

Carbone, Andreina; D'Andrea, Antonello; Riegler, Lucia; Scarafile, Raffaella; Pezzullo, Enrica; Martone, Francesca; America, Raffaella; Liccardo, Biagio; Galderisi, Maurizio; Bossone, Eduardo; Calabrò, Raffaele

2017-06-26

Intense exercise may cause heart remodeling to compensate increases in blood pressure or volume by increasing muscle mass. Cardiac changes do not involve only the left ventricle, but all heart chambers. Physiological cardiac modeling in athletes is associated with normal or enhanced cardiac function, but recent studies have documented decrements in left ventricular function during intense exercise and the release of cardiac markers of necrosis in athlete's blood of uncertain significance. Furthermore, cardiac remodeling may predispose athletes to heart disease and result in electrical remodeling, responsible for arrhythmias. Athlete's heart is a physiological condition and does not require a specific treatment. In some conditions, it is important to differentiate the physiological adaptations from pathological conditions, such as hypertrophic cardiomyopathy, arrhythmogenic dysplasia of the right ventricle, and non-compaction myocardium, for the greater risk of sudden cardiac death of these conditions. Moreover, some drugs and performance-enhancing drugs can cause structural alterations and arrhythmias, therefore, their use should be excluded.

Maintaining work capacity in the aged worker via progressive resistance training: the implications for occupational therapy practitioners.

PubMed

Branch, N G

1998-01-01

Society has an interest in maintaining the work capacity of its aging workers. Fewer and fewer younger workers are entering the workforce to replace older citizens no longer able to perform the worker role. There is a demonstrated relationship between increased strength and work capacity, yet the occupational therapy literature emphasizes generalized exercise programming. This type of programming is ineffective at building strength in the elderly worker. High intensity progressive resistance exercise (PRE) can increase strength in the very old worker, yet therapists are hesitant to employ PRE, perhaps due to a potential bias against the use of high intensity PRE with this cohort. Use of PRE may present some difficulties in the clinical situation where continual supervision and resistance training equipment is not available. The adaptive use of functional activities as a resistance training strategy to build strength may be able to overcome the difficulties attendant with the use of PRE while preserving its benefits. Several other implications for occupational therapy practitioners are discussed.

Cardiac damage in athlete’s heart: When the “supernormal” heart fails!

PubMed Central

Carbone, Andreina; D’Andrea, Antonello; Riegler, Lucia; Scarafile, Raffaella; Pezzullo, Enrica; Martone, Francesca; America, Raffaella; Liccardo, Biagio; Galderisi, Maurizio; Bossone, Eduardo; Calabrò, Raffaele

2017-01-01

Intense exercise may cause heart remodeling to compensate increases in blood pressure or volume by increasing muscle mass. Cardiac changes do not involve only the left ventricle, but all heart chambers. Physiological cardiac modeling in athletes is associated with normal or enhanced cardiac function, but recent studies have documented decrements in left ventricular function during intense exercise and the release of cardiac markers of necrosis in athlete’s blood of uncertain significance. Furthermore, cardiac remodeling may predispose athletes to heart disease and result in electrical remodeling, responsible for arrhythmias. Athlete’s heart is a physiological condition and does not require a specific treatment. In some conditions, it is important to differentiate the physiological adaptations from pathological conditions, such as hypertrophic cardiomyopathy, arrhythmogenic dysplasia of the right ventricle, and non-compaction myocardium, for the greater risk of sudden cardiac death of these conditions. Moreover, some drugs and performance-enhancing drugs can cause structural alterations and arrhythmias, therefore, their use should be excluded. PMID:28706583

Physiological responses in relation to performance during competition in elite synchronized swimmers.

PubMed

Rodríguez-Zamora, Lara; Iglesias, Xavier; Barrero, Anna; Chaverri, Diego; Erola, Pau; Rodríguez, Ferran A

2012-01-01

We aimed to characterize the cardiovascular, lactate and perceived exertion responses in relation to performance during competition in junior and senior elite synchronized swimmers. 34 high level senior (21.4 ± 3.6 years) and junior (15.9 ± 1.0) synchronized swimmers were monitored while performing a total of 96 routines during an official national championship in the technical and free solo, duet and team competitive programs. Heart rate was continuously monitored. Peak blood lactate was obtained from serial capillary samples during recovery. Post-exercise rate of perceived exertion was assessed using the Borg CR-10 scale. Total competition scores were obtained from official records. Data collection was complete in 54 cases. Pre-exercise mean heart rate (beats·min(-1)) was 129.1 ± 13.1, and quickly increased during the exercise to attain mean peak values of 191.7 ± 8.7, with interspersed bradycardic events down to 88.8 ± 28.5. Mean peak blood lactate (mmol·L(-1)) was highest in the free solo (8.5 ± 1.8) and free duet (7.6 ± 1.8) and lowest at the free team (6.2 ± 1.9). Mean RPE (0-10+) was higher in juniors (7.8 ± 0.9) than in seniors (7.1 ± 1.4). Multivariate analysis revealed that heart rate before and minimum heart rate during the routine predicted 26% of variability in final total score. Cardiovascular responses during competition are characterized by intense anticipatory pre-activation and rapidly developing tachycardia up to maximal levels with interspersed periods of marked bradycardia during the exercise bouts performed in apnea. Moderate blood lactate accumulation suggests an adaptive metabolic response as a result of the specific training adaptations attributed to influence of the diving response in synchronized swimmers. Competitive routines are perceived as very to extremely intense, particularly in the free solo and duets. The magnitude of anticipatory heart rate activation and bradycardic response appear to be related to performance variability.

Performance in sports--With specific emphasis on the effect of intensified training.

PubMed

Bangsbo, J

2015-12-01

Performance in most sports is determined by the athlete's technical, tactical, physiological and psychological/social characteristics. In the present article, the physical aspect will be evaluated with a focus on what limits performance, and how training can be conducted to improve performance. Specifically how intensified training, i.e., increasing the amount of aerobic high-intensity and speed endurance training, affects physiological adaptations and performance of trained subjects. Periods of speed endurance training do improve performance in events lasting 30 s-4 min, and when combined with aerobic high-intensity sessions, also performance during longer events. Athletes in team sports involving intense exercise actions and endurance aspects, such as soccer and basketball, can also benefit from intensified training. Speed endurance training does reduce energy expenditure and increase expression of muscle Na(+), K(+) pump α subunits, which may preserve muscle cell excitability and delay fatigue development during intense exercise. When various types of training are conducted in the same period (concurrent training), as done in a number of sports, one type of training may blunt the effect of other types of training. It is not, however, clear how various training modalities are affecting each other, and this issue should be addressed in future studies. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Psychobiological Responses to Preferred and Prescribed Intensity Exercise in Major Depressive Disorder.

PubMed

Meyer, Jacob D; Ellingson, Laura D; Koltyn, Kelli F; Stegner, Aaron J; Kim, Jee-Seon; Cook, Dane B

2016-11-01

Exercise acutely improves mood in major depressive disorder (MDD). However, it is unknown whether benefits differ depending on whether exercise intensity is self-selected or prescribed. This study aimed to compare psychological and biological responses to preferred and prescribed steady-state exercise intensities to a patient-selected preferred intensity. Female adults (N = 24, age = 38.6 ± 14.0 yr) diagnosed with MDD completed four 30-min sessions of cycling exercise at three prescribed intensities (RPE of 11, 13, and 15) and one session with a self-selected intensity (preferred). Order was randomized and counterbalanced. Depressed mood (DM) was evaluated before, 10 min, and 30 min postexercise using the Profile of Mood States. Serum brain-derived neurotrophic factor (BDNF) was measured before and within 10 min postexercise. Changes in BDNF and DM for the preferred session were compared with the following prescribed sessions: 1) performed at the most similar intensity (matched on RPE; closest) and 2) with the greatest improvement in DM (greatest). Compared with the preferred session, improvement in DM was significantly larger after the greatest session (30 min postexercise: -11.8 ± 7.4 vs -3.4 ± 4.8), and the BDNF response was significantly greater after the closest session (5.4 ± 6.9 vs -1.4 ± 9.8 ng·mL). Permitting patients to select their own exercise intensity did not maximize improvements in mood. Further, preferred intensity exercise was also associated with a smaller BDNF response. Overall, the results suggest that exercise undertaken to improve mood should be prescribed on an individual basis in MDD and not necessarily based on the patient's preferred intensity. Clinicians, psychologists, and other practitioners should consider providing clear exercise intensity recommendations for symptom management in depression rather than allowing patients to self-select their intensity.

Metabolic markers in sports medicine.

PubMed

Banfi, Giuseppe; Colombini, Alessandra; Lombardi, Giovanni; Lubkowska, Anna

2012-01-01

Physical exercise induces adaptations in metabolism considered beneficial for health. Athletic performance is linked to adaptations, training, and correct nutrition in individuals with genetic traits that can facilitate such adaptations. Intense and continuous exercise, training, and competitions, however, can induce changes in the serum concentrations of numerous laboratory parameters. When these modifications, especially elevated laboratory levels, result outside the reference range, further examinations are ordered or participation in training and competition is discontinued or sports practice loses its appeal. In order to correctly interpret commonly used laboratory data, laboratory professionals and sport physicians need to know the behavior of laboratory parameters during and after practice and competition. We reviewed the literature on liver, kidney, muscle, heart, energy, and bone parameters in athletes with a view to increase the knowledge about clinical chemistry applied to sport and to stimulate studies in this field. In liver metabolism, the interpretation of serum aminotransferases concentration in athletes should consider the release of aspartate aminotransferase (AST) from muscle and of alanine aminotransferase (ALT) mainly from the liver, when bilirubin can be elevated because of continuous hemolysis, which is typical of exercise. Muscle metabolism parameters such as creatine kinase (CK) are typically increased after exercise. This parameter can be used to interpret the physiological release of CK from muscle, its altered release due to rhabdomyolysis, or incomplete recovery due to overreaching or trauma. Cardiac markers are released during exercise, and especially endurance training. Increases in these markers should not simply be interpreted as a signal of cardiac damage or wall stress but rather as a sign of regulation of myocardial adaptation. Renal function can be followed in athletes by measuring serum creatinine concentration, but it should be interpreted considering the athlete's body-mass index (BMI) and phase of the competitive season; use of cystatin C could be a reliable alternative to creatinine. Exercise and training induce adaptations in glucose metabolism which improve glucose utilization in athletes and are beneficial for reducing insulin insensitivity in nonathletes. Glucose metabolism differs slightly for different sports disciplines, as revealed in laboratory levels. Sport activities induce a blood lipid profile superior to that of sedentary subjects. There are few reports for a definitive conclusion, however. The differences between athletes and sedentary subjects are mainly due to high-density lipoprotein cholesterol (HDLC) concentrations in physically active individuals, although some differences among sport disciplines exist. The effect of sports on serum and urinary markers for bone metabolism is not univocal; further studies are needed to establish the real and effective influence of sport on bone turnover and especially to establish its beneficial effect.

Endurance, interval sprint, and resistance exercise training: impact on microvascular dysfunction in type 2 diabetes

PubMed Central

Laughlin, M. Harold

2015-01-01

Type 2 diabetes (T2D) alters capillary hemodynamics, causes capillary rarefaction in skeletal muscle, and alters endothelial and vascular smooth muscle cell phenotype, resulting in impaired vasodilatory responses. These changes contribute to altered blood flow responses to physiological stimuli, such as exercise and insulin secretion. T2D-induced microvascular dysfunction impairs glucose and insulin delivery to skeletal muscle (and other tissues such as skin and nervous), thereby reducing glucose uptake and perpetuating hyperglycemia and hyperinsulinemia. In patients with T2D, exercise training (EX) improves microvascular vasodilator and insulin signaling and attenuates capillary rarefaction in skeletal muscle. EX-induced changes subsequently augment glucose and insulin delivery as well as glucose uptake. If these adaptions occur in a sufficient amount of tissue, and skeletal muscle in particular, chronic exposure to hyperglycemia and hyperinsulinemia and the risk of microvascular complications in all vascular beds will decrease. We postulate that EX programs that engage as much skeletal muscle mass as possible and recruit as many muscle fibers within each muscle as possible will generate the greatest improvements in microvascular function, providing that the duration of the stimulus is sufficient. Primary improvements in microvascular function occur in tissues (skeletal muscle primarily) engaged during exercise, and secondary improvements in microvascular function throughout the body may result from improved blood glucose control. We propose that the added benefit of combined resistance and aerobic EX programs and of vigorous intensity EX programs is not simply “more is better.” Rather, we believe the additional benefit is the result of EX-induced adaptations in and around more muscle fibers, resulting in more muscle mass and the associated microvasculature being changed. Thus, to acquire primary and secondary improvements in microvascular function and improved blood glucose control, EX programs should involve upper and lower body exercise and modulate intensity to augment skeletal muscle fiber recruitment. Under conditions of limited mobility, it may be necessary to train skeletal muscle groups separately to maximize whole body skeletal muscle fiber recruitment. PMID:26408541

Optimizing the "priming" effect: influence of prior exercise intensity and recovery duration on O2 uptake kinetics and severe-intensity exercise tolerance.

PubMed

Bailey, Stephen J; Vanhatalo, Anni; Wilkerson, Daryl P; Dimenna, Fred J; Jones, Andrew M

2009-12-01

It has been suggested that a prior bout of high-intensity exercise has the potential to enhance performance during subsequent high-intensity exercise by accelerating the O(2) uptake (Vo(2)) on-response. However, the optimal combination of prior exercise intensity and subsequent recovery duration required to elicit this effect is presently unclear. Eight male participants, aged 18-24 yr, completed step cycle ergometer exercise tests to 80% of the difference between the preestablished gas exchange threshold and maximal Vo(2) (i.e., 80%Delta) after no prior exercise (control) and after six different combinations of prior exercise intensity and recovery duration: 40%Delta with 3 min (40-3-80), 9 min (40-9-80), and 20 min (40-20-80) of recovery and 70%Delta with 3 min (70-3-80), 9 min (70-9-80), and 20 min (70-20-80) of recovery. Overall Vo(2) kinetics were accelerated relative to control in all conditions except for 40-9-80 and 40-20-80 conditions as a consequence of a reduction in the Vo(2) slow component amplitude; the phase II time constant was not significantly altered with any prior exercise/recovery combination. Exercise tolerance at 80%Delta was improved by 15% and 30% above control in the 70-9-80 and 70-20-80 conditions, respectively, but was impaired by 16% in the 70-3-80 condition. Prior exercise at 40%Delta did not significantly influence exercise tolerance regardless of the recovery duration. These data demonstrate that prior high-intensity exercise ( approximately 70%Delta) can enhance the tolerance to subsequent high-intensity exercise provided that it is coupled with adequate recovery duration (>or=9 min). This combination presumably optimizes the balance between preserving the effects of prior exercise on Vo(2) kinetics and providing sufficient time for muscle homeostasis (e.g., muscle phosphocreatine and H(+) concentrations) to be restored.

Individual Variability in Aerobic Fitness Adaptations to 70-d of Bed Rest and Exercise Training

NASA Technical Reports Server (NTRS)

Downs, Meghan; Buxton, Roxanne; Goetchius, Elizabeth; DeWitt, John; Ploutz-Snyder, Lori

2016-01-01

Change in maximal aerobic capacity (VO2pk) in response to exercise training and disuse is highly variable among individuals. Factors that could contribute to the observed variability (lean mass, daily activity, diet, sleep, stress) are not routinely controlled in studies. The NASA bed rest (BR) studies use a highly controlled hospital based model as an analog of spaceflight. In this study, diet, hydration, physical activity and light/dark cycles were precisely controlled and provided the opportunity to investigate individual variability. PURPOSE. Evaluate the contribution of exercise intensity and lean mass on change in VO2pk during 70-d of BR or BR + exercise. METHODS. Subjects completed 70-d of BR alone (CON, N=9) or BR + exercise (EX, N=17). The exercise prescription included 6 d/wk of aerobic exercise at 70 - 100% of max and 3 d/wk of lower body resistance exercise. Subjects were monitored 24 hr/d. VO2pk and lean mass (iDXA) were measured pre and post BR. ANOVA was used to evaluate changes in VO2pk pre to post BR. Subjects were retrospectively divided into high and low responders based on change in VO2pk (CON > 20% loss, n=5; EX >10% loss, n=4, or 5% gain, n=4) to further understand individual variability. RESULTS. VO2pk decreased from pre to post BR in CON (P<0.05) and was maintained in EX; however, significant individual variability was observed (CON: -22%, range: -39% to -.5%; EX: -1.8%, range: -16% to 12.6%). The overlap in ranges between groups included 3 CON who experienced smaller reduction in VO2pk (<16%) than the worst responding EX subjects. Individual variability was maintained when VO2pk was normalized to lean mass (range, CON: -33.7% to -5.7%; EX: -15.8% to 11%), and the overlap included 5 CON with smaller reductions in VO2pk than the worst responding EX subjects. High responders to disuse also lost the most lean mass; however, this relationship was not maintained in EX (i.e. the largest gains/losses in lean mass were observed in both high and low responders). Change in VO2pk was not related to exercise intensity. CONCLUSION. Change in VO2pk in response to disuse and exercise was highly variable among individuals, even in this tightly controlled study. Loss in lean mass accounts for a significant degree of variability in the CON; however, training induced gains in VO2pk appear unrelated to lean mass or exercise intensity.

Preferred Exertion across Three Common Modes of Exercise Training.

ERIC Educational Resources Information Center

Glass, Stephen C.; Chvala, Angela M.

2001-01-01

Examined the influence of exercise mode on self-selected exercise intensities. Participants performed three types of intensity tests. Researchers collected data on VO2 values continuously and recorded 1-minute averages several times for each submaximal test. Participants allowed to self-select exercise intensity chose work rates within the…

The Effects of Acute Exercise on Memory and Brain-Derived Neurotrophic Factor (BDNF).

PubMed

Etnier, Jennifer L; Wideman, Laurie; Labban, Jeffrey D; Piepmeier, Aaron T; Pendleton, Daniel M; Dvorak, Kelly K; Becofsky, Katie

2016-08-01

Acute exercise benefits cognition, and some evidence suggests that brain-derived neurotrophic factor (BDNF) plays a role in this effect. The purpose of this study was to explore the dose-response relationship between exercise intensity, memory, and BDNF. Young adults completed 3 exercise sessions at different intensities relative to ventilator threshold (Vt) (VO 2max , Vt - 20%, Vt + 20%). For each session, participants exercised for approximately 30 min. Following exercise, they performed the Rey Auditory Verbal Learning Test (RAVLT) to assess short-term memory, learning, and long-term memory recall. Twenty-four hours later, they completed the RAVLT recognition trial, which provided another measure of long-term memory. Blood was drawn before exercise, immediately postexercise, and after the 30-min recall test. Results indicated that long-term memory as assessed after the 24-hr delay differed as a function of exercise intensity with the largest benefits observed following maximal intensity exercise. BDNF data showed a significant increase in response to exercise; however, there were no differences relative to exercise intensity and there were no significant associations between BDNF and memory. Future research is warranted so that we can better understand how to use exercise to benefit cognitive performance.

High-intensity exercise training for the prevention of type 2 diabetes mellitus.

PubMed

Rynders, Corey A; Weltman, Arthur

2014-02-01

Aerobic exercise training and diet are recommended for the primary prevention of type 2 diabetes mellitus and cardiovascular disease. The American Diabetes Association (ADA) recommends that adults with prediabetes engage in ≥ 150 minutes per week of moderate activity and target a 7% weight loss. However, traditional moderate-intensity (MI) exercise training programs are often difficult to sustain for prediabetic adults; a commonly cited barrier to physical activity in this population is the "lack of time" to exercise. When matched for total energy expenditure, high-intensity (HI) exercise training has a lower overall time commitment compared with traditional low-intensity (LI) or MI exercise training. Several recent studies comparing HI exercise training with LI and MI exercise training reported that HI exercise training improves skeletal muscle metabolic control and cardiovascular function in a comparable and/or superior way relative to LI and MI exercise training. Although patients can accrue all exercise benefits by performing LI or MI activities such as walking, HI activities represent a time-efficient alternative to meeting physical activity guidelines. High-intensity exercise training is a potent tool for improving cardiometabolic risk for prediabetic patients with limited time and may be prescribed when appropriate.

Cancer and Exercise: Warburg Hypothesis, Tumour Metabolism and High-Intensity Anaerobic Exercise.

PubMed

Hofmann, Peter

2018-01-31

There is ample evidence that regular moderate to vigorous aerobic physical activity is related to a reduced risk for various forms of cancer to suggest a causal relationship. Exercise is associated with positive changes in fitness, body composition, and physical functioning as well as in patient-reported outcomes such as fatigue, sleep quality, or health-related quality of life. Emerging evidence indicates that exercise may also be directly linked to the control of tumour biology through direct effects on tumour-intrinsic factors. Beside a multitude of effects of exercise on the human body, one underscored effect of exercise training is to target the specific metabolism of tumour cells, namely the Warburg-type highly glycolytic metabolism. Tumour metabolism as well as the tumour⁻host interaction may be selectively influenced by single bouts as well as regularly applied exercise, dependent on exercise intensity, duration, frequency and mode. High-intensity anaerobic exercise was shown to inhibit glycolysis and some studies in animals showed that effects on tumour growth might be stronger compared with moderate-intensity aerobic exercise. High-intensity exercise was shown to be safe in patients; however, it has to be applied carefully with an individualized prescription of exercise.

Effects of treadmill exercise intensity on spatial working memory and long-term memory in rats.

PubMed

Wang, Xiao-Qin; Wang, Gong-Wu

2016-03-15

Moderate exercise promotes learning and memory. Most studies mainly focused on memory exercise effects of in the ageing and patients. There is lack of quantitative research about effect of regular exercise intensity on different memory types in normal subjects. Present study investigated the effects of different intensities of treadmill exercise on working memory and long-term memory. Fifty female Wistar rats were trained by T-maze delayed spatial alternation (DSA) task with 3 delays (10s, 60s and 300s). Then they got a 30min treadmill exercise for 30days in 4 intensities (control, 0m/min; lower, 15m/min; middle, 20m/min, and higher, 30m/min). Then animals were tested in DSA, passive avoidance and Morris water maze tasks. 1. Exercise increased the neuronal density of hippocampal subregions (CA1, CA3 and dentate gyrus) vs. naïve/control. 2. In DSA task, all groups have similar baseline, lower intensity improved 10s delay accuracy vs. baseline/control; middle and higher intensities improved 300s delay accuracy vs. baseline/control. 3. In water maze learning, all groups successfully found the platform, but middle intensity improved platform field crossing times vs. control in test phase. Present results suggested that treadmill exercise can improve long-term spatial memory and working memory; lower intensity benefits to short-term delayed working memory, and middle or higher intensity benefits to long-term delayed working memory. There was an inverted U dose-effect relationship between exercise intensity and memory performance, but exercise -working memory effect was impacted by delay duration. Copyright © 2016 Elsevier Inc. All rights reserved.

Does Physical Loading Affect The Speed and Accuracy of Tactical Decision-Making in Elite Junior Soccer Players?

PubMed Central

Frýbort, Pavel; Kokštejn, Jakub; Musálek, Martin; Süss, Vladimír

2016-01-01

A soccer player’s capability to control and manage his behaviour in a game situation is a prerequisite, reflecting not only swift and accurate tactical decision-making, but also prompt implementation of a motor task during intermittent exercise conditions. The purpose of this study was to analyse the relationship between varying exercise intensity and the visual-motor response time and the accuracy of motor response in an offensive game situation in soccer. The participants (n = 42) were male, semi-professional, soccer players (M age 18.0 ± 0.9 years) and trained five times a week. Each player performed four different modes of exercise intensity on the treadmill (motor inactivity, aerobic, intermittent and anaerobic activity). After the end of each exercise, visual-motor response time and accuracy of motor response were assessed. Players’ motion was captured by digital video camera. ANOVA indicated no significant difference (p = 0.090) in the accuracy of motor response between the four exercise intensity modes. Practical significance (Z-test = 0.31) was found in visual-motor response time between exercise with dominant involvement of aerobic metabolism, and intense intermittent exercise. A medium size effect (Z-test = 0.34) was also found in visual-motor response time between exercise with dominant involvement of aerobic metabolism and exercise with dominant involvement of anaerobic metabolism, which was confirmed by ANOVA (897.02 ± 57.46 vs. 940.95 ± 71.14; p = 0.002). The results showed that different modes of exercise intensity do not adversely affect the accuracy of motor responses; however, high-intensity exercise has a negative effect on visual-motor response time in comparison to moderate intensity exercise. Key points Different exercise intensity modes did not affect the accuracy of motor response. Anaerobic, highly intensive short-term exercise significantly decreased the visual-motor response time in comparison with aerobic exercise. Further research should focus on the assessment of VMRT from a player’s real - field position view rather than a perspective view. PMID:27274671

Cardiovascular Drift during Training for Fitness in Patients with Metabolic Syndrome.

PubMed

Morales-Palomo, Felix; Ramirez-Jimenez, Miguel; Ortega, Juan Fernando; Pallares, Jesus Garcia; Mora-Rodriguez, Ricardo

2017-03-01

The health benefits of a training program are largely influenced by the exercise dose and intensity. We sought to determine whether during a training bout of continuous versus interval exercise the workload needs to be reduced to maintain the prescribed target heart rate (HR). Fourteen obese (31 ± 4 kg·m) middle-age (57 ± 8 yr) individuals with metabolic syndrome, underwent two exercise training bouts matched by energy expenditure (i.e., 70 ± 5 min of continuous exercise [CE] or 45 min of interval exercise, high-intensity interval training [HIIT]). All subjects completed both trials in a randomized order. HR, power output (W), percent dehydration, intestinal and skin temperature (TINT and TSK), mean arterial pressure, cardiac output (CO), stroke volume (SV), and blood lactate concentration (La) were measured at the initial and latter stages of each trial to assess time-dependent drift. During the HIIT trial, power output was lowered by 30 ± 16 W to maintain the target HR, whereas a 10 ± 11 W reduction was needed in the CE trial (P < 0.05). Energy expenditure, CO, and SV declined with exercise time only in the HIIT trial (15%, 10%, and 13%, respectively). During HIIT, percent dehydration, TINT, and TSK increased more than during the CE trial (all P = 0.001). Mean arterial pressure and La were higher in HIIT without time drift in any trial. Our findings suggests that while CE results in mild power output reductions to maintain target HR, the increasingly popular HIIT results in marked reductions in power output, energy expenditure, and CO (21%, 15%, and 10%, respectively). HIIT based on target HR may result in lower than expected training adaptations because of workload adjustments to avoid HR drift.

Effects of combined high-intensity aerobic interval training program and Mediterranean diet recommendations after myocardial infarction (INTERFARCT Project): study protocol for a randomized controlled trial.

PubMed

Maldonado-Martín, Sara; Jayo-Montoya, Jon Ander; Matajira-Chia, Tatiana; Villar-Zabala, Beatriz; Goiriena, Juan José; Aispuru, G Rodrigo

2018-03-02

Exercise therapy has long been used for rehabilitation purposes after myocardial infarction (MI) and the benefit of regular physical exercise is also well-established. High-intensity interval training (HIIT) has been proposed to be more effective than continuous exercise for improving exercise capacity and health-related adaptations to low-volume (LV) and HIIT are also known. Furthermore, the Mediterranean diet (Mediet) has been widely reported to be a model of healthy eating for its contribution to a favorable health status and a better quality of life, reducing overall mortality. This study will investigate the effects of different HIIT programs (high-volume [HV] vs LV) and Mediet recommendations in clinical condition, cardiorespiratory fitness, biomarkers, ventricular function, and perception of quality of life after MI, and compared to an attention control group that is recommended to Mediet and physical activity without supervision sessions. In this randomized controlled trial, cardiorespiratory fitness, anthropometry, central and peripheral cardiovascular variables, biochemical and nutritional condition, and quality of life will be assessed before and after 16 weeks of intervention in 177 participants diagnosed with MI type 1. All participants will be randomly (1:1:1) assigned to the attention control group or two exercise groups (Mediet recommendations plus supervised aerobic exercise two days/week: (1) HV (40 min) HIIT group and (2) LV (20 min) HIIT group. This study will be the first clinical trial comparing the effects of two different volumes of HIIT programs with Mediet recommendations for people after MI. The results of this study will provide good evidence for physical rehabilitation in this population. ClinicalTrials.gov, NCT02876952 . Registered on 24 August 2016.

Using recovery modalities between training sessions in elite athletes: does it help?

PubMed

Barnett, Anthony

2006-01-01

Achieving an appropriate balance between training and competition stresses and recovery is important in maximising the performance of athletes. A wide range of recovery modalities are now used as integral parts of the training programmes of elite athletes to help attain this balance. This review examined the evidence available as to the efficacy of these recovery modalities in enhancing between-training session recovery in elite athletes. Recovery modalities have largely been investigated with regard to their ability to enhance the rate of blood lactate removal following high-intensity exercise or to reduce the severity and duration of exercise-induced muscle injury and delayed onset muscle soreness (DOMS). Neither of these reflects the circumstances of between-training session recovery in elite athletes. After high-intensity exercise, rest alone will return blood lactate to baseline levels well within the normal time period between the training sessions of athletes. The majority of studies examining exercise-induced muscle injury and DOMS have used untrained subjects undertaking large amounts of unfamiliar eccentric exercise. This model is unlikely to closely reflect the circumstances of elite athletes. Even without considering the above limitations, there is no substantial scientific evidence to support the use of the recovery modalities reviewed to enhance the between-training session recovery of elite athletes. Modalities reviewed were massage, active recovery, cryotherapy, contrast temperature water immersion therapy, hyperbaric oxygen therapy, nonsteroidal anti-inflammatory drugs, compression garments, stretching, electromyostimulation and combination modalities. Experimental models designed to reflect the circumstances of elite athletes are needed to further investigate the efficacy of various recovery modalities for elite athletes. Other potentially important factors associated with recovery, such as the rate of post-exercise glycogen synthesis and the role of inflammation in the recovery and adaptation process, also need to be considered in this future assessment.

Hormetic effects by exercise on hippocampal neurogenesis with glucocorticoid signaling

PubMed Central

Okamoto, Masahiro; Yamamura, Yuhei; Liu, Yu-Fan; Min-Chul, Lee; Matsui, Takashi; Shima, Takeru; Soya, Mariko; Takahashi, Kanako; Soya, Shingo; McEwen, Bruce S.; Soya, Hideaki

2015-01-01

Abstract Exercise enhances adult hippocampal neurogenesis (AHN), although the exact nature of how this happens remains controversial. The beneficial effects of exercise vary depending upon the exercise condition, especially intensity. Most animal studies, however, have used wheel running, which only evaluates running distance (exercise volume) and does not consider intensity. In our rat model, we have found that exercise-induced neurogenesis varies depending on the intensity of the exercise and have found that exercise-enhanced neurogenesis is more pronounced with mild exercise than with moderate and/or intense exercise. This may be due, at least in part, to increased glucocorticoid (CORT) secretion. To test this hypothesis, we used our special exercise model in mice, with and without a stress response, based on the lactate threshold (LT) in which moderate exercise above the LT increases lactate and adrenocorticotropic hormone (ACTH) release, while mild exercise does not. Adult male C57BL/6J mice were subjected to two weeks of exercise training and AHN was measured with a 5-Bromo-2-deoxyuridine (BrdU) pre-injection and immunohistochemistry. The role of glucocorticoid signaling was examined using intrapertioneal injections of antagonists for the glucocorticoid receptor (GR), mifepristone, and the mineralocorticoid receptor (MR), spironolactone. We found that, while mild exercise increased AHN without elevating CORT blood levels, both MR and GR antagonists abolished mild-exercise-induced AHN, but did not affect AHN under intense exercise. This suggests a facilitative, permissive role of glucocorticoid and mineralocorticoid receptors in AHN during mild exercise (234/250)

Physiological Tolerance to Uncompensable Heat Stress: Effects of Exercise Intensity, Protective Clothing, and Climate

DTIC Science & Technology

1994-01-01

Physiological tolerance to uncompensable heat stress: effects of exercise intensity, protective clothing , and climate SCOTT J. MONTAIN, MICHAEL N...effects of exercise 26), there remains little information to predict the inci- intensity, protective clothing , and climate. J. AppL PhysioL dence of...that pre- exercise intensity, protective clothing level, and climate on dict the physiological responses and work capability dur- physiological tolerance

The effects of two different swimming training periodization on physiological parameters at various exercise intensities.

PubMed

Clemente-Suárez, Vicente Javier; Dalamitros, Athanasios; Ribeiro, João; Sousa, Ana; Fernandes, Ricardo J; Vilas-Boas, J Paulo

2017-05-01

This study analysed the effects of two different periodization strategies on physiological parameters at various exercise intensities in competitive swimmers. Seventeen athletes of both sexes were divided to two groups, the traditional periodization (TPG, n = 7) and the reverse periodization group (RPG, n = 10). Each group followed a 10-week training period based on the two different periodization strategies. Before and after training, swimming velocity (SV), energy expenditure (EE), energy cost (EC) and percentage of aerobic (%Aer) and anaerobic (%An) energy contribution to the swimming intensities corresponding to the aerobic threshold (AerT), the anaerobic threshold (AnT) and the velocity at maximal oxygen uptake (vVO 2 max) were measured. Both groups increased the %An at the AerT and AnT intensity (P ≤ .05). In contrast, at the AnT intensity, EE and EC were only increased in TPG. Complementary, %Aer, %An, EE and EC at vVO 2 max did not alter in both groups (P > .05); no changes were observed in SV in TPG and RPG at all three intensities. These results indicate that both periodization schemes confer almost analogous adaptations in specific physiological parameters in competitive swimmers. However, given the large difference in the total training volume between the two groups, it is suggested that the implementation of the reverse periodization model is an effective and time-efficient strategy to improve performance mainly for swimming events where the AnT is an important performance indicator.

Using heart rate to prescribe physical exercise during head-out water immersion.

PubMed

Kruel, Luiz F M; Peyré-Tartaruga, Leonardo A; Coertjens, Marcelo; Dias, Adriana B C; Da Silva, Rafael C; Rangel, Antônio C B

2014-01-01

The purpose of this study was to compare and correlate the effect of age group, sex, depth of water immersion, and the heart rate (HR) assessed out of the water on the HR behavior in individuals subjected to head-out water immersion. A total of 395 healthy individuals of both sexes, aged between 07 and 75 years, underwent vertical head-out water immersion. Heart rate was assessed out of the water in the supine and orthostatic (OHR) positions and at immersion depths corresponding to the ankle, knee, hip, umbilicus, xiphoid process, acromion, neck, and also the neck with the arms out of the water. The formula (ΔHR = OHR - HR immersion depth) was used to calculate the reduction in HR at each immersion depth. No age-based or sex-based differences in HR were found. The greater the depth of the water, the greater was the decrease in HR (p < 0.05); however, no differences were found between the HR values obtained below the depth corresponding to the umbilicus. Similarly, there was a significant relationship between OHR and ΔHR measured at levels below the depth corresponding to the umbilicus (e.g., xiphoid process level: r = 0.62; p < 0.05). Therefore, this study suggests to appropriately prescribe the intensity of water-based exercise intensity performed during vertical immersion: OHR should be measured before the individual entering the aquatic environment; ΔHR should be measured according to the depth at which exercise is to be performed, and we suggest an adaptation to Karvonen's HRmax prediction formula (predicted HRmax: 220 - age - ΔHR) to prescribe and control the intensity of the exercise performed during vertical immersion.

Cold water immersion enhances recovery of submaximal muscle function after resistance exercise.

PubMed

Roberts, Llion A; Nosaka, Kazunori; Coombes, Jeff S; Peake, Jonathan M

2014-10-15

We investigated the effect of cold water immersion (CWI) on the recovery of muscle function and physiological responses after high-intensity resistance exercise. Using a randomized, cross-over design, 10 physically active men performed high-intensity resistance exercise followed by one of two recovery interventions: 1) 10 min of CWI at 10°C or 2) 10 min of active recovery (low-intensity cycling). After the recovery interventions, maximal muscle function was assessed after 2 and 4 h by measuring jump height and isometric squat strength. Submaximal muscle function was assessed after 6 h by measuring the average load lifted during 6 sets of 10 squats at 80% of 1 repetition maximum. Intramuscular temperature (1 cm) was also recorded, and venous blood samples were analyzed for markers of metabolism, vasoconstriction, and muscle damage. CWI did not enhance recovery of maximal muscle function. However, during the final three sets of the submaximal muscle function test, participants lifted a greater load (P < 0.05, Cohen's effect size: 1.3, 38%) after CWI compared with active recovery. During CWI, muscle temperature decreased ∼7°C below postexercise values and remained below preexercise values for another 35 min. Venous blood O2 saturation decreased below preexercise values for 1.5 h after CWI. Serum endothelin-1 concentration did not change after CWI, whereas it decreased after active recovery. Plasma myoglobin concentration was lower, whereas plasma IL-6 concentration was higher after CWI compared with active recovery. These results suggest that CWI after resistance exercise allows athletes to complete more work during subsequent training sessions, which could enhance long-term training adaptations. Copyright © 2014 the American Physiological Society.

Hippocampal-Brainstem Connectivity Associated with Vagal Modulation after an Intense Exercise Intervention in Healthy Men

PubMed Central

Bär, Karl-Jürgen; Herbsleb, Marco; Schumann, Andy; de la Cruz, Feliberto; Gabriel, Holger W.; Wagner, Gerd

2016-01-01

Regular physical exercise leads to increased vagal modulation of the cardiovascular system. A combination of peripheral and central processes has been proposed to underlie this adaptation. However, specific changes in the central autonomic network have not been described in human in more detail. We hypothesized that the anterior hippocampus known to be influenced by regular physical activity might be involved in the development of increased vagal modulation after a 6 weeks high intensity intervention in young healthy men (exercise group: n = 17, control group: n = 17). In addition to the determination of physical capacity before and after the intervention, we used resting state functional magnetic resonance imaging and simultaneous heart rate variability assessment. We detected a significant increase of the power output at the anaerobic threshold of 11.4% (p < 0.001), the maximum power output Pmax of 11.2% (p < 0.001), and VO2max adjusted for body weight of 4.7% (p < 0.001) in the exercise group (EG). Comparing baseline (T0) and post-exercise (T1) values of parasympathetic modulation of the exercise group, we observed a trend for a decrease in heart rate (p < 0.06) and a significant increase of vagal modulation as indicated by RMSSD (p < 0.026) during resting state. In the whole brain analysis, we found that the connectivity pattern of the right anterior hippocampus (aHC) was specifically altered to the ventromedial anterior cortex, the dorsal striatum and to the dorsal vagal complex (DVC) in the brainstem. Moreover, we observed a highly significant negative correlation between increased RMSSD after exercise and decreased functional connectivity from the right aHC to DVC (r = −0.69, p = 0.003). This indicates that increased vagal modulation was associated with functional connectivity between aHC and the DVC. In conclusion, our findings suggest that exercise associated changes in anterior hippocampal function might be involved in increased vagal modulation. PMID:27092046

The relation between exercise and glaucoma in a South Korean population-based sample.

PubMed

Lin, Shuai-Chun; Wang, Sophia Y; Pasquale, Louis R; Singh, Kuldev; Lin, Shan C

2017-01-01

To investigate the association between exercise and glaucoma in a South Korean population-based sample. Population-based, cross-sectional study. A total of 11,246 subjects, 40 years and older who underwent health care assessment as part of the 2008-2011 Korean National Health and Nutrition Examination Survey. Variables regarding the duration (total minutes per week), frequency (days per week), and intensity of exercise (vigorous, moderate exercise and walking) as well as glaucoma prevalence were ascertained for 11,246 survey participants. Demographic, comorbidity, and health-related behavior information was obtained via interview. Multivariable logistic regression analyses were performed to determine the association between the exercise-related parameters and odds of a glaucoma diagnosis. Glaucoma defined by International Society for Geographical and Epidemiological Ophthalmology criteria. Overall, 336 (2.7%) subjects met diagnostic criteria for glaucomatous disease. After adjustment for potential confounding variables, subjects engaged in vigorous exercise 7 days per week had higher odds of having glaucoma compared with those exercising 3 days per week (Odds Ratio [OR] 3.33, 95% confidence interval [CI] 1.16-9.54). High intensity of exercise, as categorized by the guidelines of the American College of Sports Medicine (ACSM), was also associated with greater glaucoma prevalence compared with moderate intensity of exercise (OR 1.55, 95% CI 1.03-2.33). There was no association between other exercise parameters including frequency of moderate exercise, walking, muscle strength exercise, flexibility training, or total minutes of exercise per week, and the prevalence of glaucoma. In sub-analyses stratifying by gender, the association between frequency of vigorous exercise 7 days per week and glaucoma diagnosis remained significant in men (OR 6.05, 95% CI 1.67-21.94) but not in women (OR 0.96 95% CI: 0.23-3.97). A U-shaped association between exercise intensity and glaucoma prevalence was noted in men (OR 1.71, 95% CI 1.09-2.69 for low intensity versus moderate intensity; OR 2.19, 95% CI 1.25-3.85 for high intensity versus moderate intensity). In a South Korean population sample, daily vigorous exercise was associated with higher glaucoma prevalence. In addition, the intensity of exercise was positively associated with glaucoma diagnosis in men but not women.

The relation between exercise and glaucoma in a South Korean population-based sample

PubMed Central

Lin, Shuai-Chun; Wang, Sophia Y.; Pasquale, Louis R.; Singh, Kuldev; Lin, Shan C.

2017-01-01

Purpose To investigate the association between exercise and glaucoma in a South Korean population-based sample. Design Population-based, cross-sectional study. Participants A total of 11,246 subjects, 40 years and older who underwent health care assessment as part of the 2008–2011 Korean National Health and Nutrition Examination Survey. Methods Variables regarding the duration (total minutes per week), frequency (days per week), and intensity of exercise (vigorous, moderate exercise and walking) as well as glaucoma prevalence were ascertained for 11,246 survey participants. Demographic, comorbidity, and health-related behavior information was obtained via interview. Multivariable logistic regression analyses were performed to determine the association between the exercise-related parameters and odds of a glaucoma diagnosis. Main outcome measure(s) Glaucoma defined by International Society for Geographical and Epidemiological Ophthalmology criteria. Results Overall, 336 (2.7%) subjects met diagnostic criteria for glaucomatous disease. After adjustment for potential confounding variables, subjects engaged in vigorous exercise 7 days per week had higher odds of having glaucoma compared with those exercising 3 days per week (Odds Ratio [OR] 3.33, 95% confidence interval [CI] 1.16–9.54). High intensity of exercise, as categorized by the guidelines of the American College of Sports Medicine (ACSM), was also associated with greater glaucoma prevalence compared with moderate intensity of exercise (OR 1.55, 95% CI 1.03–2.33). There was no association between other exercise parameters including frequency of moderate exercise, walking, muscle strength exercise, flexibility training, or total minutes of exercise per week, and the prevalence of glaucoma. In sub-analyses stratifying by gender, the association between frequency of vigorous exercise 7 days per week and glaucoma diagnosis remained significant in men (OR 6.05, 95% CI 1.67–21.94) but not in women (OR 0.96 95% CI: 0.23–3.97). A U-shaped association between exercise intensity and glaucoma prevalence was noted in men (OR 1.71, 95% CI 1.09–2.69 for low intensity versus moderate intensity; OR 2.19, 95% CI 1.25–3.85 for high intensity versus moderate intensity). Conclusion In a South Korean population sample, daily vigorous exercise was associated with higher glaucoma prevalence. In addition, the intensity of exercise was positively associated with glaucoma diagnosis in men but not women. PMID:28187143

The effect of physical exercise on salivary secretion of MUC5B, amylase and lysozyme.

PubMed

Ligtenberg, Antoon J M; Brand, Henk S; van den Keijbus, Petra A M; Veerman, Enno C I

2015-11-01

Saliva secretion is regulated by the autonomic nervous system. Parasympathic stimuli increase the secretion of water and mucin MUC5B, whereas sympathetic stimuli such as physical exercise increase the secretion of amylase and other proteins. In the present study we investigated the effect of physical exercise, as a sympathetic stimulus, on salivary flow rate and output of MUC5B, amylase, lysozyme and total protein. Unstimulated whole saliva was collected before exercise (1), after 10 min exercise with moderate intensity by running with a heart rate around 130 beats per minute (2), followed by 10 min exercise with high intensity by running to exhaustion (3) and after 30 min recovery (4). Salivary flow rate, protein and MUC5B concentration, and amylase and lysozyme activity were determined. Saliva protein composition was analysed using SDS-PAGE and immunoblotting. Salivary flow rate, protein and lysozyme secretion increased after exercise with moderate intensity and increased further after exercise with high intensity (p<0.01). Amylase and MUC5B increased after exercise with moderate intensity (p<0.0001), but did not differ significantly between moderate and high exercise intensity. SDS-PAGE analysis and immunoblotting showed that, especially after exercise with high intensity, the concentrations of several other salivary proteins, including MUC7, albumin, and extra-parotid glycoprotein, also increased. Exercise may not only lead to the anticipated increase in amylase and protein secretion, but also to an increase in salivary flow rate and MUC5B secretion. Copyright © 2015 Elsevier Ltd. All rights reserved.

ENDURANCE TRAINING IN FASTING CONDITIONS: BIOLOGICAL ADAPTATIONS AND BODY WEIGHT MANAGEMENT.

PubMed

Vicente-Salar, Néstor; Urdampilleta Otegui, Aritz; Roche Collado, Enrique

2015-12-01

in the majority of sports the athlete is required to achieve optimal conditions both at a muscular and metabolic level as well as in body composition, increasing the lean body mass and maintaining a low body fat mass. In this context, different training protocols have been proposed in order to reduce body fat content, by maximizing fat use instead of glycogen. to verify if the training while fasting favours the use of fatty acids due to the low glycogen levels, allowing an improvement in the performance ant the control of body weight. protocols have been published, differing in time periods and exercise intensity. In addition, several markers ranging from gene expression analysis to determination of circulating parameters have been assessed in order to interpret the results. Discusion: at low intensities of endurance-based exercises, adipose tissue lipolysis and muscle fat oxidation rate seem to be higher in fasting than in fed state. On the other hand, glucose metabolism is adapted in order to save glycogen stores, possibly through gluconeogenesis activation. Finally, it has been observed that protein degradation is mainly downregulated. Only one study analyses changes in body composition after fasting during long periods, thus further work is necessary to demonstrate that this is the best method to control body fat. Copyright AULA MEDICA EDICIONES 2014. Published by AULA MEDICA. All rights reserved.

The effects of exercise program on burnout and metabolic syndrome components in banking and insurance workers.

PubMed

Tsai, Han Hui; Yeh, Ching Ying; Su, Chien Tien; Chen, Chiou Jong; Peng, Shu Mei; Chen, Ruey Yu

2013-01-01

To explore the effectiveness of exercise program for banking and insurance workers and clarify the association between exercise, burnout, and metabolic syndrome components. In the process of the study, a practicable worksite exercise program was developed for bank and insurance enterprises. A three-month (12-wk) exercise course was conducted, and its benefits evaluated. Levels of burnout and metabolic syndrome components were analyzed after exercise intervention. After intervention, the indicators of burnout and metabolic syndrome components were significantly improved in both low and high intensity groups, and the improvement were expressed in reduction of waist circumference, systolic blood pressure, person burnout and work-related burnout. A dose-response of burnouts and metabolic syndrome components with exercise intensity are shown (p<0.05). Metabolic syndrome components were independently associated with burnout and exercise intensity in the crude model. After adjustment for potential confounders, waist circumference and systolic blood pressure differences showed significant associations with exercise intensity (p<0.05). This study demonstrated an effective approach to worksite exercise intervention and exercise intensity played an important role to alleviate damage between burnouts and metabolic syndrome components.

Continuous low- to moderate-intensity exercise training is as effective as moderate- to high-intensity exercise training at lowering blood HbA(1c) in obese type 2 diabetes patients.

PubMed

Hansen, D; Dendale, P; Jonkers, R A M; Beelen, M; Manders, R J F; Corluy, L; Mullens, A; Berger, J; Meeusen, R; van Loon, L J C

2009-09-01

Exercise represents an effective interventional strategy to improve glycaemic control in type 2 diabetes patients. However, the impact of exercise intensity on the benefits of exercise training remains to be established. In the present study, we compared the clinical benefits of 6 months of continuous low- to moderate-intensity exercise training with those of continuous moderate- to high-intensity exercise training, matched for energy expenditure, in obese type 2 diabetes patients. Fifty male obese type 2 diabetes patients (age 59 +/- 8 years, BMI 32 +/- 4 kg/m(2)) participated in a 6 month continuous endurance-type exercise training programme. All participants performed three supervised exercise sessions per week, either 55 min at 50% of whole body peak oxygen uptake (VO(2)peak (low to moderate intensity) or 40 min at 75% of VO(2)peak (moderate to high intensity). Oral glucose tolerance, blood glycated haemoglobin, lipid profile, body composition, maximal workload capacity, whole body and skeletal muscle oxidative capacity and skeletal muscle fibre type composition were assessed before and after 2 and 6 months of intervention. The entire 6 month intervention programme was completed by 37 participants. Continuous endurance-type exercise training reduced blood glycated haemoglobin levels, LDL-cholesterol concentrations, body weight and leg fat mass, and increased VO(2)peak, lean muscle mass and skeletal muscle cytochrome c oxidase and citrate synthase activity (p < 0.05). No differences were observed between the groups training at low to moderate or moderate to high intensity. When matched for energy cost, prolonged continuous low- to moderate-intensity endurance-type exercise training is equally effective as continuous moderate- to high-intensity training in lowering blood glycated haemoglobin and increasing whole body and skeletal muscle oxidative capacity in obese type 2 diabetes patients. ISRCTN32206301 None.

Intensity of Leisure-Time Exercise and Risk of Depressive Symptoms Among Japanese Workers: A Cohort Study.

PubMed

Kuwahara, Keisuke; Honda, Toru; Nakagawa, Tohru; Yamamoto, Shuichiro; Hayashi, Takeshi; Mizoue, Tetsuya

2018-02-05

Data on the effect of physical activity intensity on depression is scarce. We investigated the prospective association between intensity of leisure-time exercise and risk of depressive symptoms among Japanese workers. The participants were 29,052 employees (24,653 men and 4,399 women) aged 20 to 64 years without psychiatric disease including depressive symptoms at health checkup in 2006-2007 and were followed up until 2014-2015. Details of leisure-time exercise were ascertained via a questionnaire. Depressive states were assessed using a 13-item questionnaire. Multivariable-adjusted hazard ratio of depressive symptoms was estimated using Cox regression analysis. During a mean follow-up of 5.8 years with 168,203 person-years, 6,847 workers developed depressive symptoms. Compared with workers who engaged in no exercise during leisure-time (0 MET-hours per week), hazard ratios (95% confidence intervals) associated with >0 to <7.5, 7.5 to <15.0, and ≥15.0 MET-hours of leisure-time exercise were 0.88 (0.82-0.94), 0.85 (0.76-0.94), and 0.78 (0.68-0.88) among workers who engaged in moderate-intensity exercise alone; 0.93 (0.82-1.06), 0.82 (0.68-0.98), and 0.83 (0.71-0.98) among workers who engaged in vigorous-intensity exercise alone; and 0.96 (0.80-1.15), 0.80 (0.67-0.95), and 0.76 (0.66-0.87) among workers who engaged in both moderate- and vigorous-intensity exercise with adjustment for age, sex, lifestyles, work-related and socioeconomic factors, and body mass index. Additional adjustment for baseline depression score attenuated the inverse association, especially among those who engaged in moderate-intensity exercise alone. The results suggest that vigorous-intensity exercise alone or vigorous-intensity combined with moderate-intensity exercise would prevent depressive symptoms among Japanese workers.

Plasma Irisin Modestly Increases during Moderate and High-Intensity Afternoon Exercise in Obese Females

PubMed Central

Winn, Nathan C.; Grunewald, Zachary I.; Liu, Ying; Heden, Timothy D.; Nyhoff, Lauren M.; Kanaley, Jill A.

2017-01-01

Background and Purpose Irisin is an exercise-responsive myokine that has been proposed to exert anti-obesity benefits; yet its response during exercise in obese women is not described. This study characterized plasma irisin levels during a single bout of afternoon isocaloric-exercise of different intensities (moderate- vs high-intensity) in obese females. Methods Eleven obese females participated in 3 randomized study days beginning at 1600h: 1) no exercise (NoEx), 2) moderate exercise (ModEx; 55%VO2max) and 3) high intensity interval exercise (IntEx; 4 min (80%VO2max)/3 min (50% VO2max). Frequent blood samples were analyzed for glucose and lactate (whole-blood), and insulin, c-peptide, glucagon, and irisin (plasma) throughout 190 min of testing. Results Plasma irisin increased above baseline during ModEx and IntEx (P<0.05), but not NoEx (P>0.05). Peak irisin levels during ModEx and IntEx exercise were 11.9± 3.4% and 12.3 ± 4.1% relative to baseline (P<0.05), respectively, with no differences between exercise intensities (P>0.05). Irisin levels remained elevated above resting for 125 minutes post-exercise during ModEx, whereas levels returned to baseline within 15 minutes post-exercise during IntEx. Similarly, no associations were found between plasma irisin levels and circulating lactate, glucose, insulin, c-peptide, or glucagon among study days (P>0.05). However, there was an inverse association between basal irisin and lean mass (r = -0.70, P = 0.01). Conclusion A single bout of moderate and high intensity afternoon exercise induces modest increases in circulating irisin concentrations during exercise; however the regulation post-exercise appears to be dimorphic between exercise intensity in obese females. Future studies are needed to compare morning and afternoon exercise on irisin secretion. PMID:28125733

Selective training-induced thigh muscles hypertrophy in professional road cyclists.

PubMed

Hug, François; Marqueste, Tanguy; Le Fur, Yann; Cozzone, Patrick J; Grélot, Laurent; Bendahan, David

2006-07-01

Muscular adaptations linked to a high volume and intensity of training have been scarcely reported. We aimed at documenting, using MRI, the cross-sectional area changes associated with a high volume and intensity of training in 11 thigh muscles of a population of professional road cyclists as compared with sport science students. We were also interested in determining, whether selective muscle hypertrophy in professional road cyclists, if any, was correlated to selective exercise-induced T (2) changes during a pedaling exercise on a cycloergometer. Cross-sectional area of 11 thigh muscles was quantified in sixteen subjects (i.e. eight professional road cyclists and eight sport science students) using MRI. In addition, transverse relaxation times (T (2)) were measured before and just after a maximal standardized constant-load exercise in order to investigate exercise-related T (2) changes in these muscles. Professional road cyclists had a significantly higher relative amount of muscle (including the whole set of thigh muscles, 90.5+/-3.3%) as compared to controls (81.6+/-7.3%). Regarding relative values expressed with respect to the total thigh muscles CSA, Vastus lateralis and Biceps femoris CSA were significantly larger in cyclists whereas CSA of the Vastus intermedius was smaller. However, this selective hypertrophy was not correlated to the exercise-induced T (2)-increase. We have reported, for the first time, a selective hypertrophy of Vastus lateralis and Biceps femoris in professional road cyclists confirming their involvement in pedaling task and suggesting a possible cause-effect relationship between muscle activation and hypertrophy, associated with a specific pedaling skill.

Prediction of adaptive self-regulatory responses to arthritis pain anxiety in exercising adults: does pain acceptance matter?

PubMed

Cary, Miranda Ashley; Gyurcsik, Nancy C; Brawley, Lawrence R

2015-01-01

Exercising for ≥ 150 min/week is a recommended strategy for self-managing arthritis. However, exercise nonadherence is a problem. Arthritis pain anxiety may interfere with regular exercise. According to the fear-avoidance model, individuals may confront their pain anxiety by using adaptive self-regulatory responses (eg, changing exercise type or duration). Furthermore, the anxiety-self-regulatory responses relationship may vary as a function of individuals' pain acceptance levels. To investigate pain acceptance as a moderator of the pain anxiety-adaptive self-regulatory responses relationship. The secondary objective was to examine whether groups of patients who differed in meeting exercise recommendations also differed in pain-related and self-regulatory responses. Adults (mean [± SD] age 49.75 ± 13.88 years) with medically diagnosed arthritis completed online measures of arthritis pain-related variables and self-regulatory responses at baseline, and exercise participation two weeks later. Individuals meeting (n=87) and not meeting (n=49) exercise recommendations were identified. Hierarchical multiple regression analysis revealed that pain acceptance moderated the anxiety-adaptive self-regulatory responses relationship. When pain anxiety was lower, greater pain acceptance was associated with less frequent use of adaptive responses. When anxiety was higher, adaptive responses were used regardless of pain acceptance level. MANOVA findings revealed that participants meeting the recommended exercise dose reported significantly lower pain and pain anxiety, and greater pain acceptance (P<0.05) than those not meeting the dose. Greater pain acceptance may help individuals to focus their efforts to adapt to their pain anxiety only when it is higher, leaving self-regulatory capacity to cope with additional challenges to exercise adherence (eg, busy schedule).

Prediction of adaptive self-regulatory responses to arthritis pain anxiety in exercising adults: Does pain acceptance matter?

PubMed Central

Cary, Miranda A; Gyurcsik, Nancy C; Brawley, Lawrence R

2015-01-01

BACKGROUND: Exercising for ≥150 min/week is a recommended strategy for self-managing arthritis. However, exercise nonadherence is a problem. Arthritis pain anxiety may interfere with regular exercise. According to the fear-avoidance model, individuals may confront their pain anxiety by using adaptive self-regulatory responses (eg, changing exercise type or duration). Furthermore, the anxiety-self-regulatory responses relationship may vary as a function of individuals’ pain acceptance levels. OBJECTIVES: To investigate pain acceptance as a moderator of the pain anxiety-adaptive self-regulatory responses relationship. The secondary objective was to examine whether groups of patients who differed in meeting exercise recommendations also differed in pain-related and self-regulatory responses. METHODS: Adults (mean [± SD] age 49.75±13.88 years) with medically diagnosed arthritis completed online measures of arthritis pain-related variables and self-regulatory responses at baseline, and exercise participation two weeks later. Individuals meeting (n=87) and not meeting (n=49) exercise recommendations were identified. RESULTS: Hierarchical multiple regression analysis revealed that pain acceptance moderated the anxiety-adaptive self-regulatory responses relationship. When pain anxiety was lower, greater pain acceptance was associated with less frequent use of adaptive responses. When anxiety was higher, adaptive responses were used regardless of pain acceptance level. MANOVA findings revealed that participants meeting the recommended exercise dose reported significantly lower pain and pain anxiety, and greater pain acceptance (P<0.05) than those not meeting the dose. CONCLUSIONS: Greater pain acceptance may help individuals to focus their efforts to adapt to their pain anxiety only when it is higher, leaving self-regulatory capacity to cope with additional challenges to exercise adherence (eg, busy schedule). PMID:25621990

CARE CR-Cardiovascular and cardiorespiratory Adaptations to Routine Exercise-based Cardiac Rehabilitation: a study protocol for a community-based controlled study with criterion methods.

PubMed

Nichols, Simon; Nation, Fiona; Goodman, Toni; Clark, Andrew L; Carroll, Sean; Ingle, Lee

2018-01-27

Cardiac rehabilitation (CR) reduces all-cause and cardiovascular mortality in patients with coronary heart disease (CHD). Much of this improvement has been attributed to the beneficial effects of structured exercise training. However, UK-based studies have not confirmed this. Improvements in survival and cardiovascular health are associated with concurrent improvements in cardiorespiratory fitness (CRF). It is therefore concerning that estimated CRF improvements resulting from UK-based CR are approximately one-third of those reported in international literature. Modest improvements in CRF suggest that UK CR exercise training programmes may require optimisation if long-term survival is to be improved. However, contemporary UK studies lack control data or use estimates of CRF change. Cardiovascular and cardiorespiratory Adaptations to Routine Exercise-based CR is a longitudinal, observational, controlled study designed to assess the short-term and long-term effect of CR on CRF, as well cardiovascular and cardiometabolic health. Patients will be recruited following referral to their local CR programme and will either participate in a routine, low-to-moderate intensity, 8-week (16 sessions) exercise-based CR programme or freely abstain from supervised exercise. Initial assessment will be conducted prior to exercise training, or approximately 2 weeks after referral to CR if exercise training is declined. Reassessment will coincide with completion of exercise training or 10 weeks after initial assessment for control participants. Participants will receive a final follow-up 12 months after recruitment. The primary outcome will be peak oxygen consumption determined using maximal cardiopulmonary exercise testing. Secondary outcomes will include changes in subclinical atherosclerosis (carotid intima-media thickness and plaque characteristics), body composition (dual X-ray absorptiometry) and cardiometabolic biomarkers. Ethical approval for this non-randomised controlled study has been obtained from the Humber Bridge NHS Research Ethics Committee-Yorkshire and the Humber on the 27th September 2013, (12/YH/0278). Results will be presented at national conferences and published in peer-reviewed journals. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Moderating influence of dominant attentional style and exercise intensity on responses to asynchronous music.

PubMed

Hutchinson, Jasmin C; Karageorghis, Costas I

2013-12-01

We examined independent and combined influences of asynchronous music and dominant attentional style (DAS) on psychological and psychophysical variables during exercise using mixed methods. Participants (N = 34) were grouped according to DAS and completed treadmill runs at three intensities (low, moderate, high) crossed with three music conditions (motivational, oudeterous, no-music control). State attentional focus shifted from dissociative to associative with increasing intensity and was most aligned with DAS during moderate-intensity exercise. Both music conditions facilitated dissociation at low-to-moderate intensities. At high exercise intensity, both music conditions were associated with reduced RPE among participants with an associative DAS. Dissociators reported higher RPE overall during moderate and high intensities. Psychological responses were most positive in the motivational condition, followed by oudeterous and control. Findings illustrate the relevance of individual differences in DAS as well as task intensity and duration when selecting music for exercise.

Self-selected music-induced reduction of perceived exertion during moderate-intensity exercise does not interfere with post-exercise improvements in inhibitory control.

PubMed

Tanaka, Daichi; Tsukamoto, Hayato; Suga, Tadashi; Takenaka, Saki; Hamaoka, Takafumi; Hashimoto, Takeshi; Isaka, Tadao

2018-05-26

Acute aerobic exercise improves inhibitory control (IC). This improvement is often associated with increases in perceived exertion during exercise. However, listening to music during aerobic exercise mitigates an exercise-induced increase in perceived exertion. Thus, it is hypothesized that such effects of music may interfere with exercise-induced improvements in IC. To test this hypothesis, we examined the effect of music on post-exercise IC improvements that were induced by moderate-intensity exercise. Fifteen healthy young men performed cycle ergometer exercise with music or non-music. The exercise was performed using a moderate-intensity of 60% of VO 2 peak for 30 min. The music condition was performed while listening to self-selected music. The non-music condition involved no music. To evaluate IC, the Stroop task was administered before exercise, immediately after exercise, and during the 30-min post-exercise recovery period. The rate of perceived exertion immediately before moderate-intensity exercise completed was significantly lower in music condition than in non-music condition. The IC significantly improved immediately after exercise and during the post-exercise recovery period compared to before exercise in both music and non-music conditions. The post-exercise IC improvements did not significantly differ between the two conditions. These findings indicate that self-selected music-induced mitigation of the increase in perceived exertion during moderate-intensity exercise dose not interfere with exercise-induced improvements in IC. Therefore, we suggest that listening to music may be a beneficial strategy in mitigating the increase in perceived exertion during aerobic exercise without decreasing the positive effects on IC. Copyright © 2018 Elsevier Inc. All rights reserved.

Effects of interval and continuous exercise training on CD4 lymphocyte apoptotic and autophagic responses to hypoxic stress in sedentary men.

PubMed

Weng, Tzu-Pin; Huang, Shu-Chun; Chuang, Yu-Fen; Wang, Jong-Shyan

2013-01-01

Exercise is linked with the type/intensity-dependent adaptive immune responses, whereas hypoxic stress facilitates the programmed death of CD4 lymphocytes. This study investigated how high intensity-interval (HIT) and moderate intensity-continuous (MCT) exercise training influence hypoxia-induced apoptosis and autophagy of CD4 lymphocytes in sedentary men. Thirty healthy sedentary males were randomized to engage either HIT (3-minute intervals at 40% and 80%VO2max, n=10) or MCT (sustained 60%VO2max, n=10) for 30 minutes/day, 5 days/week for 5 weeks, or to a control group that did not received exercise intervention (CTL, n=10). CD4 lymphocyte apoptotic and autophagic responses to hypoxic exercise (HE, 100 W under 12%O2 for 30 minutes) were determined before and after various regimens. The results demonstrated that HIT exhibited higher enhancements of pulmonary ventilation, cardiac output, and VO2 at ventilatory threshold and peak performance than MCT did. Before the intervention, HE significantly down-regulated autophagy by decreased beclin-1, Atg-1, LC3-II, Atg-12, and LAMP-2 expressions and acridine orange staining, and simultaneously enhanced apoptosis by increased phospho-Bcl-2 and active caspase-9/-3 levels and phosphotidylserine exposure in CD4 lymphocytes. However, five weeks of HIT and MCT, but not CTL, reduced the extents of declined autophagy and potentiated apoptosis in CD4 lymphocytes caused by HE. Furthermore, both HIT and MCT regimens manifestly lowered plasma myeloperoxidase and interleukin-4 levels and elevated the ratio of interleukin-4 to interferon-γ at rest and following HE. Therefore, we conclude that HIT is superior to MCT for enhancing aerobic fitness. Moreover, either HIT or MCT effectively depresses apoptosis and promotes autophagy in CD4 lymphocytes and is accompanied by increased interleukin-4/interferon-γ ratio and decreased peroxide production during HE.

Psychophysiological Responses to Group Exercise Training Sessions: Does Exercise Intensity Matter?

PubMed

Vandoni, Matteo; Codrons, Erwan; Marin, Luca; Correale, Luca; Bigliassi, Marcelo; Buzzachera, Cosme Franklim

2016-01-01

Group exercise training programs were introduced as a strategy for improving health and fitness and potentially reducing dropout rates. This study examined the psychophysiological responses to group exercise training sessions. Twenty-seven adults completed two group exercise training sessions of moderate and vigorous exercise intensities in a random and counterbalanced order. The %HRR and the exertional and arousal responses to vigorous session were higher than those during the moderate session (p<0.05). Consequently, the affective responses to vigorous session were less pleasant than those during moderate session (p<0.05). These results suggest that the psychophysiological responses to group exercise training sessions are intensity-dependent. From an adherence perspective, interventionists are encouraged to emphasize group exercise training sessions at a moderate intensity to maximize affective responses and to minimize exertional responses, which in turn may positively affect future exercise behavior.

The Effect of Acute Exercise on Affect and Arousal in Inpatient Mental Health Consumers.

PubMed

Stanton, Robert; Reaburn, Peter; Happell, Brenda

2016-09-01

Acute exercise performed at a self-selected intensity improves affect and may improve long-term adherence. Similarly, in people with severe depression, acute aerobic exercise performed at self-selected intensity improves affect and arousal. However, the relationship between changes in affect and arousal and perceived exercise intensity in people with mental illness has not been evaluated. Affect and arousal were assessed immediately prior to, and immediately following, a group exercise program performed at a self-selected intensity in 40 inpatient mental health consumers who received a diagnosis of anxiety or bipolar or depressive disorders. Exercise intensity was assessed immediately after exercise. Postexercise affect was significantly improved for people with bipolar and depressive disorders but not for people with anxiety disorders. For the group as a whole, results showed a significant curvilinear relationship between ratings of perceived exertion and postexercise affect. These data will inform the development and delivery of future exercise interventions for inpatient mental health consumers.

High-intensity interval training evokes larger serum BDNF levels compared with intense continuous exercise.

PubMed

Saucedo Marquez, Cinthia Maria; Vanaudenaerde, Bart; Troosters, Thierry; Wenderoth, Nicole

2015-12-15

Exercise can have a positive effect on the brain by activating brain-derived neurotrophic factor (BDNF)-related processes. In healthy humans there appears to be a linear relationship between exercise intensity and the positive short-term effect of acute exercise on BDNF levels (i.e., the highest BDNF levels are reported after high-intensity exercise protocols). Here we performed two experiments to test the effectiveness of two high-intensity exercise protocols, both known to improve cardiovascular health, to determine whether they have a similar efficacy in affecting BDNF levels. Participants performed a continuous exercise (CON) protocol at 70% of maximal work rate and a high-intensity interval-training (HIT) protocol at 90% of maximal work rate for periods of 1 min alternating with 1 min of rest (both protocols lasted 20 min). We observed similar BDNF kinetics in both protocols, with maximal BDNF concentrations being reached toward the end of training (experiment 1). We then showed that both exercise protocols significantly increase BDNF levels compared with a rest condition (CON P = 0.04; HIT P < 0.001), with HIT reaching higher BDNF levels than CON (P = 0.035) (experiment 2). These results suggest that shorter bouts of high intensity exercise are slightly more effective than continuous high-intensity exercise for elevating serum BDNF. Additionally, 73% of the participants preferred the HIT protocol (P = 0.02). Therefore, we suggest that the HIT protocol might represent an effective and preferred intervention for elevating BDNF levels and potentially promoting brain health. Copyright © 2015 the American Physiological Society.

Hydration during intense exercise training.

PubMed

Maughan, R J; Meyer, N L

2013-01-01

Hydration status has profound effects on both physical and mental performance, and sports performance is thus critically affected. Both overhydration and underhydration - if sufficiently severe - will impair performance and pose a risk to health. Athletes may begin exercise in a hypohydrated state as a result of incomplete recovery from water loss induced in order to achieve a specific body mass target or due to incomplete recovery from a previous competition or training session. Dehydration will also develop in endurance exercise where fluid intake does not match water loss. The focus has generally been on training rather than on competition, but sweat loss and fluid replacement in training may have important implications. Hypohydration may impair training quality and may also increase stress levels. It is unclear whether this will have negative effects (reduced training quality, impaired immunity) or whether it will promote a greater adaptive response. Hypohydration and the consequent hyperthermia, however, can enhance the effectiveness of a heat acclimation program, resulting in improved endurance performance in warm and temperate environments. Drinking in training may be important in enhancing tolerance of the gut when athletes plan to drink in competition. The distribution of water between body water compartments may also be important in the initiation and promotion of cellular adaptations to the training stimulus. Copyright © 2013 Nestec Ltd., Vevey/S. Karger AG, Basel.

Contributions of Astronauts Aerobic Exercise Intensity and Time on Change in VO2peak during Spaceflight

NASA Technical Reports Server (NTRS)

Downs, Meghan E.; Buxton, Roxanne; Moore, Alan; Ploutz-Snyder, Robert; Ploutz-Snyder, Lori

2014-01-01

There is considerable variability among astronauts with respect to changes in maximal aerobic capacity (VO2peak) during International Space Station (ISS) missions, ranging from a 5% increase to 30% decline. Individual differences may be due to in-flight aerobic exercise time and intensity. PURPOSE: To evaluate the effects of in-flight aerobic exercise time and intensity on change in VO2peak during ISS missions. METHODS: Astronauts (N=11) performed peak cycle tests approx 60 days before flight (L-60), on flight day (FD) approx 14, and every approx 30 days thereafter. Metabolic gas analysis and heart rate (HR) were measured continuously during the test using the portable pulmonary function system. HR and duration of each in-flight cycle ergometer and treadmill (TM) session were recorded and averaged in time segments corresponding to each peak test. Mixed effects linear regression with exercise mode (TM or cycle) as a categorical variable was used to assess the contributions of exercise intensity (%time >70% peak HR or %time >90% peak HR) and time (min/wk), adjusted for body weight, on %change in VO2peak during the mission, and incorporating the repeated-measures experimental design. RESULTS: 110 observations were included in the model (4-6 peak cycle tests per astronaut, 2 exercise devices). VO2peak was reduced from preflight throughout the mission (FD14: 13+/-13% and FD 105: 8+/-10%). Exercise intensity (%peak HR: FD14=66+/-14; FD105=75+/-8) and time (min/wk: FD14=82+/-46; FD105=158+/-40) increased during flight. The models showed main effects for exercise time and intensity with no interactions between time, intensity, and device (70% peak HR: time [z-score=2.39; P=0.017], intensity [z-score=3.51; P=0.000]; 90% peak HR: time [zscore= 3.31; P=0.001], intensity [z-score=2.24; P=0.025]). CONCLUSION: Exercise time and intensity independently contribute to %change in VO2peak during ISS missions, indicating that there are minimal values for exercise time and intensity required to maintain VO2peak. As the FD105 average exercise intensity and time did not prevent a decline in VO2peak from preflight, astronauts' exercise prescriptions should target at least 160 min of weekly aerobic exercise at an average above 75% peak HR with increased time at intensities above 90% of peak HR starting early in the mission.

Post-plyometric exercise hypotension and heart rate in normotensive individuals: influence of exercise intensity.

PubMed

Arazi, Hamid; Asadi, Abbas; Rahimzadeh, Mehdi; Moradkhani, Amir-Hossein

2013-12-01

The purpose of this study was to compare the effects of high, moderate and low intensity plyometric exercise on the post-exercise systolic and diastolic blood pressure and heart rate responses. Ten healthy normotensive men (age, 21.1±0.9 years; height, 175.8±6 cm; and body mass, 69.1±13.6 kg) volunteered to participate in this study and were evaluated for three non-consecutive days in depth jump exercise from 20-cm box (low intensity [LI]), 40-cm box (moderate intensity [MI]) and 60-cm box (high intensity [HI]) for 5 sets of 20 repetitions. After each exercise session, systolic blood pressure (SBP), diastolic blood pressure (DBP) and heart rate (HR) were measured every 10 min for a period of 90 min. No significant differences were observed among post-exercise SBP, DBP and HR when the protocols (LI, MI and HI) were compared. The LI and HI protocols showed greater reduction in SBP at 40(th)-70(th) min of post-exercise (~9%), whereas the LI and MI protocols indicated greater reduction in DBP at 10(th)-50(th) min of post exercise (~10%). In addition, the change in the DBP for HI was not significant and the increases in the HR were similar for all intensities. It can be concluded that a plyometric exercise (PE) can reduce SBP and DBP post-exercise and therefore we can say that PE has significant effects for reducing BP and HR or post-exercise hypotension.

Mitochondria-specific antioxidant supplementation does not influence endurance exercise training-induced adaptations in circulating angiogenic cells, skeletal muscle oxidative capacity or maximal oxygen uptake.

PubMed

Shill, Daniel D; Southern, W Michael; Willingham, T Bradley; Lansford, Kasey A; McCully, Kevin K; Jenkins, Nathan T

2016-12-01

Reducing excessive oxidative stress, through chronic exercise or antioxidants, can decrease the negative effects induced by excessive amounts of oxidative stress. Transient increases in oxidative stress produced during acute exercise facilitate beneficial vascular training adaptations, but the effects of non-specific antioxidants on exercise training-induced vascular adaptations remain elusive. Circulating angiogenic cells (CACs) are an exercise-inducible subset of white blood cells that maintain vascular integrity. We investigated whether mitochondria-specific antioxidant (MitoQ) supplementation would affect the response to 3 weeks of endurance exercise training in CACs, muscle mitochondrial capacity and maximal oxygen uptake in young healthy men. We show that endurance exercise training increases multiple CAC types, an adaptation that is not altered by MitoQ supplementation. Additionally, MitoQ does not affect skeletal muscle or whole-body aerobic adaptations to exercise training. These results indicate that MitoQ supplementation neither enhances nor attenuates endurance training adaptations in young healthy men. Antioxidants have been shown to improve endothelial function and cardiovascular outcomes. However, the effects of antioxidants on exercise training-induced vascular adaptations remain elusive. General acting antioxidants combined with exercise have not impacted circulating angiogenic cells (CACs). We investigated whether mitochondria-specific antioxidant (MitoQ) supplementation would affect the response to 3 weeks of endurance exercise training on CD3 + , CD3 + /CD31 + , CD14 + /CD31 + , CD31 + , CD34 + /VEGFR2 + and CD62E + peripheral blood mononuclear cells (PBMCs), muscle mitochondrial capacity, and maximal oxygen uptake (VO2 max ) in healthy men aged 22.1 ± 0.7 years, with a body mass index of 26.9 ± 0.9 kg m -2 , and 24.8 ± 1.3% body fat. Analysis of main effects revealed that training induced 33, 105 and 285% increases in CD14 + /CD31 + , CD62E + and CD34 + /VEGFR2 + CACs, respectively, and reduced CD3 + /CD31 - PBMCs by 14%. There was no effect of MitoQ on CAC levels. Also independent of MitoQ supplementation, exercise training significantly increased quadriceps muscle mitochondrial capacity by 24% and VO2 max by roughly 7%. In conclusion, endurance exercise training induced increases in multiple CAC types, and this adaptation is not modified by MitoQ supplementation. Furthermore, we demonstrate that a mitochondrial-targeted antioxidant does not influence skeletal muscle or whole-body aerobic adaptations to exercise training. © 2016 The Authors. The Journal of Physiology © 2016 The Physiological Society.

Exercise intensity modulates the change in cerebral blood flow following aerobic exercise in chronic stroke.

PubMed

Robertson, Andrew D; Crane, David E; Rajab, A Saeed; Swardfager, Walter; Marzolini, Susan; Shirzadi, Zahra; Middleton, Laura E; MacIntosh, Bradley J

2015-08-01

The mechanisms supporting functional improvement by aerobic exercise following stroke remain incompletely understood. This study investigated how cycling intensity and aerobic fitness influence cerebral blood flow (CBF) following a single exercise session. Thirteen community-living stroke survivors performed 20 min of semi-recumbent cycling at low and moderate intensities (40-50 and 60-70 % of heart rate reserve, respectively) as determined from an exercise stress test. CBF was quantified by arterial spin labeling MRI at baseline, as well as 30 and 50 min post-exercise. An intensity-dependent effect was observed in the right post-central and supramarginal gyri up to 50 min after exercise (uncorrected p < 0.005, cluster size ≥10). Regional CBF was increased 18 ± 17 % and reduced 8 ± 12 % following moderate- and low-intensity cycling, respectively. In contrast, CBF changes were similar between sessions in the right lentiform nucleus and mid-frontal gyrus, as well as the left temporal and parietal gyri. Aerobic fitness was directly related to posterior cingulate and thalamic CBF, and inversely related to precuneal CBF at rest (R (2) ≥ 0.75); however, no relationship between fitness and the post-exercise change in CBF was observed. Divergent changes in regional CBF were observed in the right parietal cortex following low- and moderate-intensity exercise, which suggests that intensity of prescribed exercise may be useful in optimizing rehabilitation.

Exercise training during normobaric hypoxic confinement does not alter hormonal appetite regulation.

PubMed

Debevec, Tadej; Simpson, Elizabeth J; Macdonald, Ian A; Eiken, Ola; Mekjavic, Igor B

2014-01-01

Both exposure to hypoxia and exercise training have the potential to modulate appetite and induce beneficial metabolic adaptations. The purpose of this study was to determine whether daily moderate exercise training performed during a 10-day exposure to normobaric hypoxia alters hormonal appetite regulation and augments metabolic health. Fourteen healthy, male participants underwent a 10-day hypoxic confinement at ∼ 4000 m simulated altitude (FIO2 = 0.139 ± 0.003%) either combined with daily moderate intensity exercise (Exercise group; N = 8, Age = 25.8 ± 2.4 yrs, BMI = 22.9 ± 1.2 kg · m(-2)) or without any exercise (Sedentary group; N = 6 Age = 24.8 ± 3.1 yrs, BMI = 22.3 ± 2.5 kg · m(-2)). A meal tolerance test was performed before (Pre) and after the confinement (Post) to quantify fasting and postp randial concentrations of selected appetite-related hormones and metabolic risk markers. 13C-Glucose was dissolved in the test meal and 13CO2 determined in breath samples. Perceived appetite ratings were obtained throughout the meal tolerance tests. While body mass decreased in both groups (-1.4 kg; p = 0.01) following the confinement, whole body fat mass was only reduced in the Exercise group (-1.5 kg; p = 0.01). At Post, postprandial serum insulin was reduced in the Sedentary group (-49%; p = 0.01) and postprandial plasma glucose in the Exercise group (-19%; p = 0.03). Fasting serum total cholesterol levels were reduced (-12%; p = 0.01) at Post in the Exercise group only, secondary to low-density lipoprotein cholesterol reduction (-16%; p = 0.01). No differences between groups or testing periods were noted in fasting and/or postprandial concentrations of total ghrelin, peptide YY, and glucagon-like peptide-1, leptin, adiponectin, expired 13CO2 as well as perceived appetite ratings (p>0.05). These findings suggest that performing daily moderate intensity exercise training during continuous hypoxic exposure does not alter hormonal appetite regulation but can improve the lipid profile in healthy young males.

Exercise frequency and bone mineral density development in exercising postmenopausal osteopenic women. Is there a critical dose of exercise for affecting bone? Results of the Erlangen Fitness and Osteoporosis Prevention Study.

PubMed

Kemmler, Wolfgang; von Stengel, Simon; Kohl, Matthias

2016-08-01

Due to older people's low sports participation rates, exercise frequency may be the most critical component for designing exercise protocols that address bone. The aims of the present article were to determine the independent effect of exercise frequency (ExFreq) and its corresponding changes on bone mineral density (BMD) and to identify the minimum effective dose that just relevantly affects bone. Based on the 16-year follow-up of the intense, consistently supervised Erlangen Fitness and Osteoporosis Prevention-Study, ExFreq was retrospectively determined in the exercise-group of 55 initially early-postmenopausal females with osteopenia. Linear mixed-effect regression analysis was conducted to determine the independent effect of ExFreq on BMD changes at lumbar spine and total hip. Minimum effective dose of ExFreq based on BMD changes less than the 90% quantile of the sedentary control-group (n=43). Cut-offs were determined after 4, 8, 12 and 16years using bootstrap with 5000 replications. After 16years, average ExFreq ranged between 1.02 and 2.96sessions/week (2.28±0.40sessions/week). ExFreq has an independent effect on LS-BMD (p<.001) and hip-BMD (p=.005) changes. Bootstrap analysis detected a minimum effective dose at about 2sessions/week/16years (cut-off LS-BMD: 2.11, 95% CI: 2.06-2.12; total hip-BMD: 2.22, 95% CI: 2.00-2.78sessions/week/16years). In summary, the minimum effective dose of exercise frequency that relevantly addresses BMD is quite high, at least compared with the low sport participation rate of older adults. This result might not be generalizable across all exercise types, protocols and cohorts, but it does indicate at least that even when applying high impact/high intensity programs, exercise frequency and its maintenance play a key role in bone adaptation. Copyright © 2016 Elsevier Inc. All rights reserved.

Interleukin-6 and associated cytokine responses to an acute bout of high-intensity interval exercise: the effect of exercise intensity and volume.

PubMed

Cullen, Tom; Thomas, Andrew W; Webb, Richard; Hughes, Michael G

2016-08-01

Acute increases in interleukin (IL)-6 following prolonged exercise are associated with the induction of a transient anti-inflammatory state (e.g., increases in IL-10) that is partly responsible for the health benefits of regular exercise. The purposes of this study were to investigate the IL-6-related inflammatory response to high-intensity interval exercise (HIIE) and to determine the impact of exercise intensity and volume on this response. Ten participants (5 males and 5 females) completed 3 exercise bouts of contrasting intensity and volume (LOW, MOD, and HIGH). The HIGH protocol was based upon standard HIIE protocols, while the MOD and LOW protocols were designed to enable a comparison of exercise intensity and volume with a fixed duration. Inflammatory cytokine concentrations were measured in plasma (IL-6, IL-10) and also determined the level of gene expression (IL-6, IL-10, and IL-4R) in peripheral blood. The plasma IL-6 response to exercise (reported as fold changes) was significantly greater in HIGH (2.70 ± 1.51) than LOW (1.40 ± 0.32) (P = 0.04) and was also positively correlated to the mean exercise oxygen uptake (r = 0.54, P < 0.01). However, there was no change in anti-inflammatory IL-10 or IL-4R responses in plasma or at the level of gene expression. HIIE caused a significant increase in IL-6 and was greater than that seen in low-intensity exercise of the same duration. The increases in IL-6 were relatively small in magnitude, and appear to have been insufficient to induce the acute systemic anti-inflammatory effects, which are evident following longer duration exercise.

How should COPD patients exercise during respiratory rehabilitation? Comparison of exercise modalities and intensities to treat skeletal muscle dysfunction

PubMed Central

Puhan, M; Schunemann, H; Frey, M; Scharplatz, M; Bachmann, L

2005-01-01

Background: Physical exercise is an important component of respiratory rehabilitation because it reverses skeletal muscle dysfunction, a clinically important manifestation of COPD associated with reduced health-related quality of life (HRQL) and survival. However, there is controversy regarding the components of the optimal exercise protocol. A study was undertaken to systematically evaluate and summarise randomised controlled trials (RCTs) comparing different exercise protocols for COPD patients. Methods: Six electronic databases, congress proceedings and bibliographies of included studies were searched without imposing language restrictions. Two reviewers independently screened all records and extracted data on study samples, interventions and methodological characteristics of included studies. Results: The methodological quality of the 15 included RCTs was low to moderate. Strength exercise led to larger improvements of HRQL than endurance exercise (weighted mean difference for Chronic Respiratory Questionnaire 0.27, 95% CI 0.02 to 0.52). Interval exercise seems to be of similar effectiveness as continuous exercise, but there are few data on clinically relevant outcomes. One small RCT which included patients with mild COPD compared the effect of high and low intensity exercise (at 80% and 40% of the maximum exercise capacity, respectively) and found larger physiological training effects from high intensity exercise. Conclusions: Strength exercise should be routinely incorporated in respiratory rehabilitation. There is insufficient evidence to recommend high intensity exercise for COPD patients and investigators should conduct larger high quality trials to evaluate exercise intensities in patients with moderate to severe COPD. PMID:15860711

Evidence based exercise - clinical benefits of high intensity interval training.

PubMed

Shiraev, Tim; Barclay, Gabriella

2012-12-01

Aerobic exercise has a marked impact on cardiovascular disease risk. Benefits include improved serum lipid profiles, blood pressure and inflammatory markers as well as reduced risk of stroke, acute coronary syndrome and overall cardiovascular mortality. Most exercise programs prescribed for fat reduction involve continuous, moderate aerobic exercise, as per Australian Heart Foundation clinical guidelines. This article describes the benefits of exercise for patients with cardiovascular and metabolic disease and details the numerous benefits of high intensity interval training (HIIT) in particular. Aerobic exercise has numerous benefits for high-risk populations and such benefits, especially weight loss, are amplified with HIIT. High intensity interval training involves repeatedly exercising at a high intensity for 30 seconds to several minutes, separated by 1-5 minutes of recovery (either no or low intensity exercise). HIT is associated with increased patient compliance and improved cardiovascular and metabolic outcomes and is suitable for implementation in both healthy and 'at risk' populations. Importantly, as some types of exercise are contraindicated in certain patient populations and HIIT is a complex concept for those unfamiliar to exercise, some patients may require specific assessment or instruction before commencing a HIIT program.

Effect of High-Intensity Treadmill Exercise on Motor Symptoms in Patients With De Novo Parkinson Disease: A Phase 2 Randomized Clinical Trial.

PubMed

Schenkman, Margaret; Moore, Charity G; Kohrt, Wendy M; Hall, Deborah A; Delitto, Anthony; Comella, Cynthia L; Josbeno, Deborah A; Christiansen, Cory L; Berman, Brian D; Kluger, Benzi M; Melanson, Edward L; Jain, Samay; Robichaud, Julie A; Poon, Cynthia; Corcos, Daniel M

2018-02-01

Parkinson disease is a progressive neurologic disorder. Limited evidence suggests endurance exercise modifies disease severity, particularly high-intensity exercise. To examine the feasibility and safety of high-intensity treadmill exercise in patients with de novo Parkinson disease who are not taking medication and whether the effect on motor symptoms warrants a phase 3 trial. The Study in Parkinson Disease of Exercise (SPARX) was a phase 2, multicenter randomized clinical trial with 3 groups and masked assessors. Individuals from outpatient and community-based clinics were enrolled from May 1, 2012, through November 30, 2015, with the primary end point at 6 months. Individuals with idiopathic Parkinson disease (Hoehn and Yahr stages 1 or 2) aged 40 to 80 years within 5 years of diagnosis who were not exercising at moderate intensity greater than 3 times per week and not expected to need dopaminergic medication within 6 months participated in this study. A total of 384 volunteers were screened by telephone; 128 were randomly assigned to 1 of 3 groups (high-intensity exercise, moderate-intensity exercise, or control). High-intensity treadmill exercise (4 days per week, 80%-85% maximum heart rate [n = 43]), moderate-intensity treadmill exercise (4 days per week, 60%-65% maximum heart rate [n = 45]), or wait-list control (n = 40) for 6 months. Feasibility measures were adherence to prescribed heart rate and exercise frequency of 3 days per week and safety. The clinical outcome was 6-month change in Unified Parkinson's Disease Rating Scale motor score. A total of 128 patients were included in the study (mean [SD] age, 64 [9] years; age range, 40-80 years; 73 [57.0%] male; and 108 [84.4%] non-Hispanic white). Exercise rates were 2.8 (95% CI, 2.4-3.2) days per week at 80.2% (95% CI, 78.8%-81.7%) maximum heart rate in the high-intensity group and 3.2 (95% CI, 2.8-3.6; P = .13) days per week at 65.9% (95% CI, 64.2%-67.7%) maximum heart rate in the moderate-intensity group (P < .001). The mean change in Unified Parkinson's Disease Rating Scale motor score in the high-intensity group was 0.3 (95% CI, -1.7 to 2.3) compared with 3.2 (95% CI, 1.4 to 5.1) in the usual care group (P = .03). The high-intensity group, but not the moderate-intensity group, reached the predefined nonfutility threshold compared with the control group. Anticipated adverse musculoskeletal events were not severe. High-intensity treadmill exercise may be feasible and prescribed safely for patients with Parkinson disease. An efficacy trial is warranted to determine whether high-intensity treadmill exercise produces meaningful clinical benefits in de novo Parkinson disease. clinicaltrials.gov Identifier: NCT01506479.

Acute high-intensity interval exercise reduces the postprandial glucose response and prevalence of hyperglycaemia in patients with type 2 diabetes.

PubMed

Gillen, J B; Little, J P; Punthakee, Z; Tarnopolsky, M A; Riddell, M C; Gibala, M J

2012-06-01

High-volume endurance exercise (END) improves glycaemic control in type 2 diabetes (T2D) but many individuals cite 'lack of time' as a barrier to regular participation. High-intensity interval training (HIT) is a time-efficient method to induce physiological adaptations similar to END, but little is known regarding the effect of HIT in T2D. Using continuous glucose monitoring (CGM), we examined the 24-h blood glucose response to one session of HIT consisting of 10 × 60 s cycling efforts at ~90% maximal heart rate, interspersed with 60 s rest. Seven adults with T2D underwent CGM for 24-h on two occasions under standard dietary conditions: following acute HIT and on a non-exercise control day (CTL). HIT reduced hyperglycaemia measured as proportion of time spent above 10 mmol/l (HIT: 4.5 ± 4.4 vs. CTL: 15.2 ± 12.3%, p = 0.04). Postprandial hyperglycaemia, measured as the sum of post-meal areas under the glucose curve, was also lower after HIT vs. CTL (728 ± 331 vs. 1142 ± 556 mmol/l·9 h, p = 0.01). These findings highlight the potential for HIT to improve glycaemic control in T2D. © 2012 Blackwell Publishing Ltd.

Stretch-activated ion channel blockade attenuates adaptations to eccentric exercise.

PubMed

Butterfield, Timothy A; Best, Thomas M

2009-02-01

The purpose of this study was to test the hypothesis that stretch-activated ion channel (SAC) function is essential for the repeated bout effect (RBE) in skeletal muscle. Specifically, we investigated if daily injections of streptomycin (a known SAC blocker) would abrogate the muscle's adaptive resistance to the damaging effects of eccentric exercise over a 4-wk period. Furthermore, we hypothesized that the lack of an RBE would be due to the lack of functional adaptations that typically result from repeated bouts of eccentric exercise, including increased peak isometric torque, muscle hypertrophy, and rightward shift of the torque-angle relationship. Twelve New Zealand white rabbits were each subjected to 12 bouts of eccentric exercise over a 4-wk period while receiving either daily injections of streptomycin or sham injections. Although blocking the SAC function completely eliminated the expected adaptive response in biomechanical parameters during the exercise regimen, there remained evidence of an acquired RBE, albeit with an attenuated response when compared with the muscles with intact SAC function. Blocking sarcolemmal SAC eliminates functional adaptations of muscle after eccentric exercise. In the absence of SAC function, muscles subjected to chronic eccentric exercise still exhibit some degree of the RBE. As such, it appears that the signaling cascade that results in functional, biomechanical adaptations associated with the RBE during eccentric exercise is dependent upon intact SAC function.

Effects of exercise intensity on spatial memory performance and hippocampal synaptic plasticity in transient brain ischemic rats.

PubMed

Shih, Pei-Cheng; Yang, Yea-Ru; Wang, Ray-Yau

2013-01-01

Memory impairment is commonly noted in stroke survivors, and can lead to delay of functional recovery. Exercise has been proved to improve memory in adult healthy subjects. Such beneficial effects are often suggested to relate to hippocampal synaptic plasticity, which is important for memory processing. Previous evidence showed that in normal rats, low intensity exercise can improve synaptic plasticity better than high intensity exercise. However, the effects of exercise intensities on hippocampal synaptic plasticity and spatial memory after brain ischemia remain unclear. In this study, we investigated such effects in brain ischemic rats. The middle cerebral artery occlusion (MCAO) procedure was used to induce brain ischemia. After the MCAO procedure, rats were randomly assigned to sedentary (Sed), low-intensity exercise (Low-Ex), or high-intensity exercise (High-Ex) group. Treadmill training began from the second day post MCAO procedure, 30 min/day for 14 consecutive days for the exercise groups. The Low-Ex group was trained at the speed of 8 m/min, while the High-Ex group at the speed of 20 m/min. The spatial memory, hippocampal brain-derived neurotrophic factor (BDNF), synapsin-I, postsynaptic density protein 95 (PSD-95), and dendritic structures were examined to document the effects. Serum corticosterone level was also quantified as stress marker. Our results showed the Low-Ex group, but not the High-Ex group, demonstrated better spatial memory performance than the Sed group. Dendritic complexity and the levels of BDNF and PSD-95 increased significantly only in the Low-Ex group as compared with the Sed group in bilateral hippocampus. Notably, increased level of corticosterone was found in the High-Ex group, implicating higher stress response. In conclusion, after brain ischemia, low intensity exercise may result in better synaptic plasticity and spatial memory performance than high intensity exercise; therefore, the intensity is suggested to be considered during exercise training.

Autonomic function responses to training: Correlation with body composition changes.

PubMed

Tian, Ye; Huang, Chuanye; He, Zihong; Hong, Ping; Zhao, Jiexiu

2015-11-01

The causal relation between autonomic function and adiposity is an unresolved issue. Thus, we studied whether resting heart rate variability (HRV) changes could be used to predict changes in body composition after 16 weeks of individualized exercise training. A total of 117 sedentary overweight/obese adults volunteered to join an intervention group (IN, n=82) or a control group (CON, n=35). The intervention group trained for 30-40 min three times a week with an intensity of 85-100% of individual ventilatory threshold (Thvent). At baseline and after a 16-week training period, resting HRV variables, body composition and peak oxygen uptake (VO2peak) were assessed. Compared with CON, exercise training significantly improved HRV and body composition and increased VO2peak (P<0.05). Significant correlations were observed between changes of HRV variables and body composition indices and VO2peak (P<0.05). Greater individual changes in HRV in response to exercise training were observed for those with greater total and central fat loss. Individual aerobic-based exercise training was for improving autonomic function and resting HRV responses to aerobic training is a potential indicator for adaptations to exercise training. Copyright © 2015. Published by Elsevier Inc.

[Metabolic effects of exercise on childhood obesity: a current view].

PubMed

Paes, Santiago Tavares; Marins, João Carlos Bouzas; Andreazzi, Ana Eliza

2015-01-01

To review the current literature concerning the effects of physical exercise on several metabolic variables related to childhood obesity. A search was performed in Pubmed/Medline and Web of Science databases. The keywords used were as follows: Obesity, Children Obesity, Childhood Obesity, Exercise and Physical Activity. The online search was based on studies published in English, from April 2010 to December 2013. Search queries returned 88,393 studies based on the aforementioned keywords; 4,561 studies were selected by crossing chosen keywords. After applying inclusion criteria, four studies were selected from 182 eligible titles. Most studies have found that aerobic and resistance training improves body composition, lipid profile and metabolic and inflammatory status of obese children and adolescents; however, the magnitude of the effects is associated with the type, intensity and duration of practice. Regardless of type, physical exercise promotes positive adaptations to childhood obesity, mainly acting to restore cellular and cardiovascular homeostasis, to improve body composition, and to activate metabolism; therefore, physical exercise acts as a co-factor in combating obesity. Copyright © 2014 Associação de Pediatria de São Paulo. Publicado por Elsevier Editora Ltda. All rights reserved.

Effect of local cooling on short-term, intense exercise.

PubMed

Kwon, Young S; Robergs, Robert A; Schneider, Suzanne M

2013-07-01

The widespread belief that local cooling impairs short-term, strenuous exercise performance is controversial. Eighteen original investigations involving cooling before and intermittent cooling during short-term, intensive exercise are summarized in this review. Previous literature examining short-term intensive exercise and local cooling primarily has been limited to the effects on muscle performance immediately or within minutes following cold application. Most previous cooling studies used equal and longer than 10 minutes of pre-cooling, and found that cooling reduced strength, performance and endurance. Because short duration, high intensity exercise requires adequate warm-up to prepare for optimal performance, prolonged pre-cooling is not an effective method to prepare for this type of exercise. The literature related to the effect of acute local cooling immediately before short duration, high intensity isotonic exercise such as weight lifting is limited. However, local intermittent cooling during short-term, high intense exercise may provide possible beneficial effects; first, by pain reduction, caused by an "irritation effect" from hand thermal receptors which block pain sensation, or second, by a cooling effect, whereby stimulation of hand thermal receptors or a slight lowering of blood temperature might alter central fatigue.

Effects of Exercise on Physiological and Psychological Variables in Cancer Survivors.

ERIC Educational Resources Information Center

Burnham, Timothy; Wilcox, Anthony

2002-01-01

Investigated the effect of aerobic exercise on physiological and psychological function in people rehabilitating from cancer treatment. Data on people participating in control, moderate-intensity exercise, and low-intensity exercise groups indicated that both exercise programs were equally effective in improving physiological function,…

Can high-intensity exercise be more pleasant?: attentional dissociation using music and video.

PubMed

Jones, Leighton; Karageorghis, Costas I; Ekkekakis, Panteleimon

2014-10-01

Theories suggest that external stimuli (e.g., auditory and visual) may be rendered ineffective in modulating attention when exercise intensity is high. We examined the effects of music and parkland video footage on psychological measures during and after stationary cycling at two intensities: 10% of maximal capacity below ventilatory threshold and 5% above. Participants (N = 34) were exposed to four conditions at each intensity: music only, video only, music and video, and control. Analyses revealed main effects of condition and exercise intensity for affective valence and perceived activation (p < .001), state attention (p < .05), and exercise enjoyment (p < .001). The music-only and music-and-video conditions led to the highest valence and enjoyment scores during and after exercise regardless of intensity. Findings indicate that attentional manipulations can exert a salient influence on affect and enjoyment even at intensities slightly above ventilatory threshold.

Effect of Exercise Intensity and Duration on Postexercise Executive Function.

PubMed

Tsukamoto, Hayato; Takenaka, Saki; Suga, Tadashi; Tanaka, Daichi; Takeuchi, Tatsuya; Hamaoka, Takafumi; Isaka, Tadao; Hashimoto, Takeshi

2017-04-01

The effect of exercise volume represented by exercise intensity and duration on postexercise executive function (EF) improvement remains unclear. In the present study, involving two volume-controlled evaluations, we aimed to compare acute exercise protocols with differing intensities and durations to establish an effective exercise protocol for improving EF. In study 1, 12 healthy male subjects performed cycle ergometer exercise, based on a low-intensity (LI) protocol for 20 min (LI20), moderate-intensity (MI) protocol for 20 min (MI20), and MI20 volume-matched LI protocol for 40 min (LI40). The exercise intensities for the LI and MI were set at 30% and 60% of peak oxygen consumption, respectively. In study 2, 15 healthy male subjects performed MI exercise for 10 min (MI10), MI20, and 40 min (MI40). To evaluate the EF, the color-word Stroop task was administrated before exercise, immediately after exercise, and during the 30-min postexercise recovery. In study 1, postexercise EF improvement was sustained for a longer duration after MI20 than after LI40 and was sustained for a longer duration after LI40 than after LI20. In study 2, although there was no significant difference in post-MI exercise EF improvement, the magnitude of difference in the EF between preexercise and 30-min postexercise recovery period was moderately larger in MI40, but not in MI10 and MI20, indicating that the EF improvement during postexercise recovery could be sustained after MI40. The present findings showed that postexercise EF improvement could be prolonged after MI exercise with a moderate duration compared with volume-matched LI exercise with a longer duration. In addition, MI exercise with a relatively long duration may slightly prolong the postexercise EF improvement.

Effects of High Intensity Interval Training on Increasing Explosive Power, Speed, and Agility

NASA Astrophysics Data System (ADS)

Fajrin, F.; Kusnanik, N. W.; Wijono

2018-01-01

High Intensity Interval Training (HIIT) is a type of exercise that combines high-intensity exercise and low intensity exercise in a certain time interval. This type of training is very effective and efficient to improve the physical components. The process of improving athletes achievement related to how the process of improving the physical components, so the selection of a good practice method will be very helpful. This study aims to analyze how is the effects of HIIT on increasing explosive power, speed, and agility. This type of research is quantitative with quasi-experimental methods. The design of this study used the Matching-Only Design, with data analysis using the t-test (paired sample t-test). After being given the treatment for six weeks, the results showed there are significant increasing in explosive power, speed, and agility. HIIT in this study used a form of exercise plyometric as high-intensity exercise and jogging as mild or moderate intensity exercise. Increase was due to the improvement of neuromuscular characteristics that affect the increase in muscle strength and performance. From the data analysis, researchers concluded that, Exercises of High Intensity Interval Training significantly effect on the increase in Power Limbs, speed, and agility.

Randomized controlled trial evaluating the temporal effects of high-intensity exercise on learning, short-term and long-term memory, and prospective memory.

PubMed

Frith, Emily; Sng, Eveleen; Loprinzi, Paul D

2017-11-01

The broader purpose of this study was to examine the temporal effects of high-intensity exercise on learning, short-term and long-term retrospective memory and prospective memory. Among a sample of 88 young adult participants, 22 were randomized into one of four different groups: exercise before learning, control group, exercise during learning, and exercise after learning. The retrospective assessments (learning, short-term and long-term memory) were assessed using the Rey Auditory Verbal Learning Test. Long-term memory including a 20-min and 24-hr follow-up assessment. Prospective memory was assessed using a time-based procedure by having participants contact (via phone) the researchers at a follow-up time period. The exercise stimulus included a 15-min bout of progressive maximal exertion treadmill exercise. High-intensity exercise prior to memory encoding (vs. exercise during memory encoding or consolidation) was effective in enhancing long-term memory (for both 20-min and 24-h follow-up assessments). We did not observe a differential temporal effect of high-intensity exercise on short-term memory (immediate post-memory encoding), learning or prospective memory. The timing of high-intensity exercise may play an important role in facilitating long-term memory. © 2017 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

Muscle and intensity based hamstring exercise classification in elite female track and field athletes: implications for exercise selection during rehabilitation.

PubMed

Tsaklis, Panagiotis; Malliaropoulos, Nikos; Mendiguchia, Jurdan; Korakakis, Vasileios; Tsapralis, Kyriakos; Pyne, Debasish; Malliaras, Peter

2015-01-01

Hamstring injuries are common in many sports, including track and field. Strains occur in different parts of the hamstring muscle but very little is known about whether common hamstring loading exercises specifically load different hamstring components. The purpose of this study was to investigate muscle activation of different components of the hamstring muscle during common hamstring loading exercises. Twenty elite female track and field athletes were recruited into this study, which had a single-sample, repeated-measures design. Each athlete performed ten hamstring loading exercises, and an electromyogram (EMG) was recorded from the biceps femoris and semitendinosus components of the hamstring. Hamstring EMG during maximal voluntary isometric contraction (MVIC) was used to normalize the mean data across ten repetitions of each exercise. An electrogoniometer synchronized to the EMG was used to determine whether peak EMG activity occurred during muscle-tendon unit lengthening, shortening, or no change in length. Mean EMG values were compared between the two recording sites for each exercise using the Student's t-test. The lunge, dead lift, and kettle swings were low intensity (<50% MVIC) and all showed higher EMG activity for semitendinosus than for biceps femoris. Bridge was low but approaching medium intensity, and the TRX, hamstring bridge, and hamstring curl were all medium intensity exercises (≥50% or <80% MVIC). The Nordic, fitball, and slide leg exercises were all high intensity exercises. Only the fitball exercise showed higher EMG activity in the biceps femoris compared with the semitendinosus. Only lunge and kettle swings showed peak EMG in the muscle-tendon unit lengthening phase and both these exercises involved faster speed. Some exercises selectively activated the lateral and medial distal hamstrings. Low, medium, and high intensity exercises were demonstrated. This information enables the clinician, strength and conditioning coach and physiotherapist to better understand intensity- and muscle-specific activation during hamstring muscle rehabilitation. Therefore, these results may help in designing progressive strengthening and rehabilitation and prevention programs.

Usefulness of a Perceived Exertion Scale for Monitoring Exercise Intensity in Adults with Intellectual Disabilities

ERIC Educational Resources Information Center

Stanish, Heidi I.; Aucoin, Michael

2007-01-01

In order to gain physical fitness and health, exercise must be performed at a sufficient level of intensity. Exercise intensity can be monitored with rated perceived exertion (RPE) scales to promote safe and effective programming. The usefulness of the Children's OMNI Scale as a subjective measure of intensity for adults with intellectual…

Intense Exercise Promotes Adult Hippocampal Neurogenesis But Not Spatial Discrimination

PubMed Central

So, Ji H.; Huang, Chao; Ge, Minyan; Cai, Guangyao; Zhang, Lanqiu; Lu, Yisheng; Mu, Yangling

2017-01-01

Hippocampal neurogenesis persists throughout adult life and plays an important role in learning and memory. Although the influence of physical exercise on neurogenesis has been intensively studied, there is controversy in regard to how the impact of exercise may vary with its regime. Less is known about how distinct exercise paradigms may differentially affect the learning behavior. Here we found that, chronic moderate treadmill running led to an increase of cell proliferation, survival, neuronal differentiation, and migration. In contrast, intense running only promoted neuronal differentiation and migration, which was accompanied with lower expressions of vascular endothelial growth factor, brain-derived neurotrophic factor, insulin-like growth factor 1, and erythropoietin. In addition, the intensely but not mildly exercised animals exhibited a lower mitochondrial activity in the dentate gyrus. Correspondingly, neurogenesis induced by moderate but not intense exercise was sufficient to improve the animal’s ability in spatial pattern separation. Our data indicate that the effect of exercise on spatial learning is intensity-dependent and may involve mechanisms other than a simple increase in the number of new neurons. PMID:28197080

Exercise does not enhance aged bone's impaired response to artificial loading in C57Bl/6 mice.

PubMed

Meakin, Lee B; Udeh, Chinedu; Galea, Gabriel L; Lanyon, Lance E; Price, Joanna S

2015-12-01

Bones adapt their structure to their loading environment and so ensure that they become, and are maintained, sufficiently strong to withstand the loads to which they are habituated. The effectiveness of this process declines with age and bones become fragile fracturing with less force. This effect in humans also occurs in mice which experience age-related bone loss and reduced adaptation to loading. Exercise engenders many systemic and local muscular physiological responses as well as engendering local bone strain. To investigate whether these physiological responses influence bones' adaptive responses to mechanical strain we examined whether a period of treadmill exercise influenced the adaptive response to an associated period of artificial loading in young adult (17-week) and old (19-month) mice. After treadmill acclimatization, mice were exercised for 30 min three times per week for two weeks. Three hours after each exercise period, right tibiae were subjected to 40 cycles of non-invasive axial loading engendering peak strain of 2250 με. In both young and aged mice exercise increased cross-sectional muscle area and serum sclerostin concentration. In young mice it also increased serum IGF1. Exercise did not affect bone's adaptation to loading in any measured parameter in young or aged bone. These data demonstrate that a level of exercise sufficient to cause systemic changes in serum, and adaptive changes in local musculature, has no effect on bone's response to loading 3h later. This study provides no support for the beneficial effects of exercise on bone in the elderly being mediated by systemic or local muscle-derived effects rather than local adaptation to altered mechanical strain. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

High-Intensity Interval vs. Continuous Endurance Training: Preventive Effects on Hormonal Changes and Physiological Adaptations in Prediabetes Patients.

PubMed

Safarimosavi, Saleh; Mohebbi, Hamid; Rohani, Hadi

2018-06-22

Safarimosavi, S, Mohebbi, H, and Rohani, H. High-intensity interval vs. continuous endurance training: Preventive effects on hormonal changes and physiological adaptations in prediabetes patients. J Strength Cond Res XX(X): 000-000, 2018-The aim of this study was to examine the effects of a 12-week high-intensity interval training (HIIT) intervention, or an isocaloric continuous endurance training (CET) intervention on insulin resistance indices and change in irisin and preptin in patients with prediabetes. Thirty-two prediabetic male patients (age = 38.7 ± 4; body mass index = 26.9 ± 1.4 kg·m; and V[Combining Dot Above]O2peak = 2.49 ± 0.22 L·min) were randomly assigned into 3 training groups (N = 8). These groups were matched based on the required energy expenditure (EE) for completing each protocol: (a) HIIT (10 × 60 seconds at 90% peak oxygen uptake [V[Combining Dot Above]O2peak], 1: 1 work to recovery at 50 W), (b) CET at an intensity equivalent to maximal fat oxidation (Fatmax) (CETFAT) (pedaling for a duration that expends an equivalent EE to an HIIT session [E ≈ HIIT]), (c) CET at an intensity equivalent to anaerobic threshold (CETAT) (E ≈ HIIT), and (d) the control group (CON): continued to perform their daily activities. After intervention, blood glucose levels were significantly (p < 0.05) lower in the HIIT group compared with CETAT group. Exercise training improved the insulin resistance index by 35, 28, and 37% in CETFAT, CETAT, and HIIT groups, respectively. Irisin concentrations in the HIIT and CETAT groups was significantly (p < 0.05) decreased compared with the pre-training values. Also, HIIT and CETFAT resulted in significant (p < 0.05) changes in preptin concentration compared with baseline. This study demonstrated that both HIIT and CETFAT protocols had similar effects on the insulin resistance index of prediabetic patients. Also, the intensity and type of exercise were effective factors in changing irisin and preptin concentrations.

β-hydroxy-β-methylbutyrate free acid supplementation may improve recovery and muscle adaptations after resistance training: a systematic review.

PubMed

Silva, Vagner R; Belozo, Felipe L; Micheletti, Thayana O; Conrado, Marcelo; Stout, Jeffrey R; Pimentel, Gustavo D; Gonzalez, Adam M

2017-09-01

β-Hydroxy-β-methylbutyrate free acid (HMB-FA) has been suggested to accelerate the regenerative capacity of skeletal muscle after high-intensity exercise and attenuate markers of skeletal muscle damage. Herein a systematic review on the use of HMB-FA supplementation as an ergogenic aid to improve measures of muscle recovery, performance, and hypertrophy after resistance training was conducted. This review was performed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. We included randomized, double-blinded, placebo-controlled trials investigating the effects of HMB-FA supplementation in conjunction with resistance exercise in humans. The search was conducted using Medline and Google Scholar databases for the terms beta-hydroxy-beta-methylbutyrate, HMB free acid, exercise, resistance exercise, strength training, and HMB supplementation. Only research articles published from 1996 to 2016 in English language were considered for the analysis. Nine studies met the criteria for inclusion in the analyses. Most studies included resistance-trained men, and the primary intervention strategy involved administration of 3g of HMB-FA per day. In conjunction with resistance training, HMB-FA supplementation may attenuate markers of muscle damage, augment acute immune and endocrine responses, and enhance training-induced muscle mass and strength. HMB-FA supplementation may also improve markers of aerobic fitness when combined with high-intensity interval training. Nevertheless, more studies are needed to determine the overall efficacy of HMB-FA supplementation as an ergogenic aid. Copyright © 2017 Elsevier Inc. All rights reserved.

Cardiorespiratory demand of acute voluntary cycling with functional electrical stimulation in individuals with multiple sclerosis with severe mobility impairment.

PubMed

Edwards, Thomas; Motl, Robert W; Pilutti, Lara A

2018-01-01

Exercise training is one strategy for improving cardiorespiratory fitness (CRF) in multiple sclerosis (MS); however, few modalities are accessible for those with severe mobility impairment. Functional electrical stimulation (FES) cycling is an adapted exercise modality with the potential for improving CRF in people with severe MS. The objective of this study was to characterize the cardiorespiratory response of acute voluntary cycling with FES in people with MS with severe mobility impairment, and to compare this response to passive leg cycling. Eleven participants with MS that required assistance for ambulation completed a single bout of voluntary cycling with FES or passive leg cycling. Oxygen consumption, heart rate (HR), work rate (WR), and ratings of perceived exertion (RPE) were recorded throughout the session. For the FES group, mean exercising oxygen consumption was 8.7 ± 1.8 mL/(kg·min) -1 , or 63.5% of peak oxygen consumption. Mean HR was 102 ± 9.7 bpm, approximately 76.4% of peak HR. Mean WR was 27.0 ± 9.2 W, or 57.3% of peak WR, and median RPE was 13.5 (interquartile range = 5.5). Active cycling with FES was significantly (p < 0.05) more intense than passive leg cycling based on oxygen consumption, HR, WR, and RPE during exercise. In conclusion, voluntary cycling with FES elicited an acute response that corresponded with moderate-to vigorous-intensity activity, suggesting that active cycling with FES can elicit a sufficient stimulus for improving CRF.

W' expenditure and reconstitution during severe intensity constant power exercise: mechanistic insight into the determinants of W'.

PubMed

Broxterman, Ryan M; Skiba, Phillip F; Craig, Jesse C; Wilcox, Samuel L; Ade, Carl J; Barstow, Thomas J

2016-10-01

The sustainable duration of severe intensity exercise is well-predicted by critical power (CP) and the curvature constant (W'). The development of the W'BAL model allows for the pattern of W' expenditure and reconstitution to be characterized and this model has been applied to intermittent exercise protocols. The purpose of this investigation was to assess the influence of relaxation phase duration and exercise intensity on W' reconstitution during dynamic constant power severe intensity exercise. Six men (24.6 ± 0.9 years, height: 173.5 ± 1.9 cm, body mass: 78.9 ± 5.6 kg) performed severe intensity dynamic handgrip exercise to task failure using 50% and 20% duty cycles. The W'BAL model was fit to each exercise test and the time constant for W' reconstitution (τW') was determined. The τW' was significantly longer for the 50% duty cycle (1640 ± 262 sec) than the 20% duty cycle (863 ± 84 sec, P = 0.02). Additionally, the relationship between τW' and CP was well described as an exponential decay (r(2) = 0.90, P < 0.0001). In conclusion, the W'BAL model is able to characterize the expenditure and reconstitution of W' across the contraction-relaxation cycles comprising severe intensity constant power handgrip exercise. Moreover, the reconstitution of W' during constant power severe intensity exercise is influenced by the relative exercise intensity, the duration of relaxation between contractions, and CP. © 2016 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.

Mitochondria‐specific antioxidant supplementation does not influence endurance exercise training‐induced adaptations in circulating angiogenic cells, skeletal muscle oxidative capacity or maximal oxygen uptake

PubMed Central

Shill, Daniel D.; Southern, W. Michael; Willingham, T. Bradley; Lansford, Kasey A.; McCully, Kevin K.

2016-01-01

Key points Reducing excessive oxidative stress, through chronic exercise or antioxidants, can decrease the negative effects induced by excessive amounts of oxidative stress. Transient increases in oxidative stress produced during acute exercise facilitate beneficial vascular training adaptations, but the effects of non‐specific antioxidants on exercise training‐induced vascular adaptations remain elusive.Circulating angiogenic cells (CACs) are an exercise‐inducible subset of white blood cells that maintain vascular integrity.We investigated whether mitochondria‐specific antioxidant (MitoQ) supplementation would affect the response to 3 weeks of endurance exercise training in CACs, muscle mitochondrial capacity and maximal oxygen uptake in young healthy men.We show that endurance exercise training increases multiple CAC types, an adaptation that is not altered by MitoQ supplementation. Additionally, MitoQ does not affect skeletal muscle or whole‐body aerobic adaptations to exercise training.These results indicate that MitoQ supplementation neither enhances nor attenuates endurance training adaptations in young healthy men. Abstract Antioxidants have been shown to improve endothelial function and cardiovascular outcomes. However, the effects of antioxidants on exercise training‐induced vascular adaptations remain elusive. General acting antioxidants combined with exercise have not impacted circulating angiogenic cells (CACs). We investigated whether mitochondria‐specific antioxidant (MitoQ) supplementation would affect the response to 3 weeks of endurance exercise training on CD3+, CD3+/CD31+, CD14+/CD31+, CD31+, CD34+/VEGFR2+ and CD62E+ peripheral blood mononuclear cells (PBMCs), muscle mitochondrial capacity, and maximal oxygen uptake (VO2 max ) in healthy men aged 22.1 ± 0.7 years, with a body mass index of 26.9 ± 0.9 kg m–2, and 24.8 ± 1.3% body fat. Analysis of main effects revealed that training induced 33, 105 and 285% increases in CD14+/CD31+, CD62E+ and CD34+/VEGFR2+ CACs, respectively, and reduced CD3+/CD31− PBMCs by 14%. There was no effect of MitoQ on CAC levels. Also independent of MitoQ supplementation, exercise training significantly increased quadriceps muscle mitochondrial capacity by 24% and VO2 max by roughly 7%. In conclusion, endurance exercise training induced increases in multiple CAC types, and this adaptation is not modified by MitoQ supplementation. Furthermore, we demonstrate that a mitochondrial‐targeted antioxidant does not influence skeletal muscle or whole‐body aerobic adaptations to exercise training. PMID:27501153

Exercise Prescriptions for Training and Rehabilitation in Patients with Heart and Lung Disease.

PubMed

Palermo, Pietro; Corrà, Ugo

2017-07-01

Rehabilitation in patients with advanced cardiac and pulmonary disease has been shown to increase survival and improve quality of life, among many other benefits. Exercise training is the fundamental ingredient in these rehabilitation programs. However, determining the amount of exercise is not straightforward or uniform. Most rehabilitation and training programs fix the time of exercise and set the exercise intensity to the goals of the rehabilitation program and the exercise-related hurdles of the individual. The exercise training intensity prescription must balance the desired gain in conditioning with safety. Symptom-limited cardiopulmonary exercise testing is the fundamental tool to identify the exercise intensity and define the appropriate training. In addition, cardiopulmonary exercise testing provides an understanding of the systems involved in oxygen transport and utilization, making it possible to identify the factors limiting exercise capacity in individual patients.

Effect of resistance exercise intensity on the expression of PGC-1α isoforms and the anabolic and catabolic signaling mediators, IGF-1 and myostatin, in human skeletal muscle.

PubMed

Schwarz, Neil A; McKinley-Barnard, Sarah K; Spillane, Mike B; Andre, Thomas L; Gann, Joshua J; Willoughby, Darryn S

2016-08-01

The purpose of this study was to investigate the acute messenger (mRNA) expression of the peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) isoforms, insulin-like growth factor-1Ea (IGF-1Ea), and myostatin in response to 2 resistance exercise intensities. In a uniform-balanced, crossover design, 10 participants performed 2 separate testing sessions involving a lower body resistance exercise component consisting of a lower intensity (50% of 1-repetition maximum; 1RM) protocol and a higher intensity (80% of 1RM) protocol of equal volumes. Muscle samples were obtained at before exercise, 45 min, 3 h, 24 h, and 48 h postexercise. Resistance exercise did not alter total PGC-1α mRNA expression; however, distinct responses of each PGC-1α isoform were observed. The response of each isoform was consistent between sessions, suggesting no effect of resistance exercise intensity on the complex transcriptional expression of the PGC-1α gene. IGF-1Ea mRNA expression significantly increased following the higher intensity session compared with pre-exercise and the lower intensity session. Myostatin mRNA expression was significantly reduced compared with pre-exercise values at all time points with no difference between exercise intensity. Further research is needed to determine the effects of the various isoforms of PGC-1α in human skeletal muscle on the translational level as well as their relation to the expression of IGF-1 and myostatin.

Carbohydrate availability and exercise training adaptation: too much of a good thing?

PubMed

Bartlett, Jonathan D; Hawley, John A; Morton, James P

2015-01-01

Traditional nutritional approaches to endurance training have typically promoted high carbohydrate (CHO) availability before, during and after training sessions to ensure adequate muscle substrate to meet the demands of high daily training intensities and volumes. However, during the past decade, data from our laboratories and others have demonstrated that deliberately training in conditions of reduced CHO availability can promote training-induced adaptations of human skeletal muscle (i.e. increased maximal mitochondrial enzyme activities and/or mitochondrial content, increased rates of lipid oxidation and, in some instances, improved exercise capacity). Such data have led to the concept of 'training low, but competing high' whereby selected training sessions are completed in conditions of reduced CHO availability (so as to promote training adaptation), but CHO reserves are restored immediately prior to an important competition. The augmented training response observed with training-low strategies is likely regulated by enhanced activation of key cell signalling kinases (e.g. AMPK, p38MAPK), transcription factors (e.g. p53, PPARδ) and transcriptional co-activators (e.g. PGC-1α), such that a co-ordinated up-regulation of both the nuclear and mitochondrial genomes occurs. Although the optimal practical strategies to train low are not currently known, consuming additional caffeine, protein, and practising CHO mouth-rinsing before and/or during training may help to rescue the reduced training intensities that typically occur when 'training low', in addition to preventing protein breakdown and maintaining optimal immune function. Finally, athletes should practise 'train-low' workouts in conjunction with sessions undertaken with normal or high CHO availability so that their capacity to oxidise CHO is not blunted on race day.

Affect-regulated exercise intensity: does training at an intensity that feels 'good' improve physical health?

PubMed

Parfitt, Gaynor; Alrumh, Amnah; Rowlands, Alex V

2012-11-01

Affect-regulated exercise to feel 'good' can be used to control exercise intensity amongst both active and sedentary individuals and should support exercise adherence. It is not known, however, whether affect-regulated exercise training can lead to physical health gains. The aim of this study was to examine if affect-regulated exercise to feel 'good' leads to improved fitness over the course of an 8-week training programme. A repeated measures design (pretest-posttest) with independent groups (training and control). 20 sedentary females completed a submaximal graded exercise test and were then allocated to either a training group or control group. The training group completed two supervised sessions and one unsupervised session per week for 8 weeks. Exercise intensity was affect-regulated to feel 'good'. Following the 8 weeks of training, both groups completed a second submaximal graded exercise test. Repeated measures analyses of variance indicated a significant increase in the time to reach ventilatory threshold in the training group (318 ± 23.7s) compared to control (248 ± 16.9s). Overall compliance to training was high (>92%). Participants in the training group exercised at intensities that would be classified as being in the lower range of the recommended guidelines (≈ 50% V˙O(2) max) for cardiovascular health. Affect-regulated exercise to feel 'good' can be used in a training programme to regulate exercise intensity. This approach led to a 19% increase in time to reach ventilatory threshold, which is indicative of improved fitness. Copyright © 2012 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Post-Plyometric Exercise Hypotension and Heart Rate in Normotensive Individuals: Influence of Exercise Intensity

PubMed Central

Arazi, Hamid; Asadi, Abbas; Rahimzadeh, Mehdi; Moradkhani, Amir-Hossein

2013-01-01

Purpose The purpose of this study was to compare the effects of high, moderate and low intensity plyometric exercise on the post-exercise systolic and diastolic blood pressure and heart rate responses. Methods Ten healthy normotensive men (age, 21.1±0.9 years; height, 175.8±6 cm; and body mass, 69.1±13.6 kg) volunteered to participate in this study and were evaluated for three non-consecutive days in depth jump exercise from 20-cm box (low intensity [LI]), 40-cm box (moderate intensity [MI]) and 60-cm box (high intensity [HI]) for 5 sets of 20 repetitions. After each exercise session, systolic blood pressure (SBP), diastolic blood pressure (DBP) and heart rate (HR) were measured every 10 min for a period of 90 min. Results No significant differences were observed among post-exercise SBP, DBP and HR when the protocols (LI, MI and HI) were compared. The LI and HI protocols showed greater reduction in SBP at 40th-70th min of post-exercise (~9%), whereas the LI and MI protocols indicated greater reduction in DBP at 10th-50th min of post exercise (~10%). In addition, the change in the DBP for HI was not significant and the increases in the HR were similar for all intensities. Conclusion It can be concluded that a plyometric exercise (PE) can reduce SBP and DBP post-exercise and therefore we can say that PE has significant effects for reducing BP and HR or post-exercise hypotension. PMID:24799997

Muscle damage and inflammation during recovery from exercise.

PubMed

Peake, Jonathan M; Neubauer, Oliver; Della Gatta, Paul A; Nosaka, Kazunori

2017-03-01

Unaccustomed exercise consisting of eccentric (i.e., lengthening) muscle contractions often results in muscle damage characterized by ultrastructural alterations in muscle tissue, clinical signs, and symptoms (e.g., reduced muscle strength and range of motion, increased muscle soreness and swelling, efflux of myocellular proteins). The time course of recovery following exercise-induced muscle damage depends on the extent of initial muscle damage, which in turn is influenced by the intensity and duration of exercise, joint angle/muscle length, and muscle groups used during exercise. The effects of these factors on muscle strength, soreness, and swelling are well characterized. By contrast, much less is known about how they affect intramuscular inflammation and molecular aspects of muscle adaptation/remodeling. Although inflammation has historically been viewed as detrimental for recovery from exercise, it is now generally accepted that inflammatory responses, if tightly regulated, are integral to muscle repair and regeneration. Animal studies have revealed that various cell types, including neutrophils, macrophages, mast cells, eosinophils, CD8 and T-regulatory lymphocytes, fibro-adipogenic progenitors, and pericytes help to facilitate muscle tissue regeneration. However, more research is required to determine whether these cells respond to exercise-induced muscle damage. A large body of research has investigated the efficacy of physicotherapeutic, pharmacological, and nutritional interventions for reducing the signs and symptoms of exercise-induced muscle damage, with mixed results. More research is needed to examine if/how these treatments influence inflammation and muscle remodeling during recovery from exercise. Copyright © 2017 the American Physiological Society.

Resistance Exercise to Prevent and Manage Sarcopenia and Dynapenia

PubMed Central

Law, Timothy D.; Clark, Leatha A.; Clark, Brian C.

2016-01-01

For well over twenty centuries the muscle wasting (sarcopenia) and weakness (dynapenia) that occurs with old age has been a predominant concern of mankind. Exercise has long been suggested as a treatment to combat sarcopenia and dynapenia, as it exerts effects on both the nervous and muscular systems that are critical to positive physiological and functional adaptations (e.g., enhanced muscle strength). For more than two decades scientists have recognized the profound role that progressive resistance exercise training can have on increasing muscle strength, muscle size and functional capacity in older adults. In this review article we discuss how resistance exercise training can be used in the management and prevention of sarcopenia and dynapenia. We first provide an overview of the evidence for this notion and highlight certain critical factors— namely exercise intensity, volume and progression— that are key to optimizing the resistance exercise prescription. We then highlight how many, if not most, of the commonly prescribed exercise programs for seniors are not the ‘best practices’, and subsequently present easy-to-read guidelines for a well-rounded resistance exercise training program designed for the management and prevention of sarcopenia and dynapenia, including example training programs for the beginner through the advanced senior resistance exerciser. These guidelines have been written for the academician as well as the student and health care provider across a variety of disciplines, including those in the long term care industry, such as wellness instructors or activity directors. PMID:27134329

Resistance Exercise to Prevent and Manage Sarcopenia and Dynapenia.

PubMed

Law, Timothy D; Clark, Leatha A; Clark, Brian C

For well over twenty centuries the muscle wasting (sarcopenia) and weakness (dynapenia) that occurs with old age has been a predominant concern of mankind. Exercise has long been suggested as a treatment to combat sarcopenia and dynapenia, as it exerts effects on both the nervous and muscular systems that are critical to positive physiological and functional adaptations (e.g., enhanced muscle strength). For more than two decades scientists have recognized the profound role that progressive resistance exercise training can have on increasing muscle strength, muscle size and functional capacity in older adults. In this review article we discuss how resistance exercise training can be used in the management and prevention of sarcopenia and dynapenia. We first provide an overview of the evidence for this notion and highlight certain critical factors- namely exercise intensity, volume and progression- that are key to optimizing the resistance exercise prescription. We then highlight how many, if not most, of the commonly prescribed exercise programs for seniors are not the 'best practices', and subsequently present easy-to-read guidelines for a well-rounded resistance exercise training program designed for the management and prevention of sarcopenia and dynapenia, including example training programs for the beginner through the advanced senior resistance exerciser. These guidelines have been written for the academician as well as the student and health care provider across a variety of disciplines, including those in the long term care industry, such as wellness instructors or activity directors.

Acute psychological benefits of aerobic exercise: a field study into the effects of exercise characteristics.

PubMed

Rendi, Mária; Szabo, Attila; Szabó, Tamás; Velenczei, Attila; Kovács, Arpád

2008-03-01

Eighty volunteers were tested in their natural exercise environment consisting of a fitness centre they regularly attended. Half of the sample exercised on a stationary bicycle, the other half on a treadmill. All participants filled in the Exercise-Induced Feeling Inventory before and after their 20 min of exercise that was performed at self-selected workload. The results revealed that exercise intensity and the other parallel measures like heart rate, perceived exercise intensity and estimates of burned calories were higher in participants who ran in contrast to those who cycled. There were no differences in self-reports of enjoyment of the exercise sessions and in the psychological improvements from pre- to post-exercise between the groups. It is concluded that significant psychological improvements occur even after a 20-min bout of exercise and these changes are independent of the workload or exercise intensity.

Blood flow regulation and oxygen uptake during high-intensity forearm exercise.

PubMed

Nyberg, S K; Berg, O K; Helgerud, J; Wang, E

2017-04-01

The vascular strain is very high during heavy handgrip exercise, but the intensity and kinetics to reach peak blood flow, and peak oxygen uptake, are uncertain. We included 9 young (25 ± 2 yr) healthy males to evaluate blood flow and oxygen uptake responses during continuous dynamic handgrip exercise with increasing intensity. Blood flow was measured using Doppler-ultrasound, and venous blood was drawn from a deep forearm vein to determine arteriovenous oxygen difference (a-vO 2diff ) during 6-min bouts of 60, 80, and 100% of maximal work rate (WR max ), respectively. Blood flow and oxygen uptake increased ( P < 0.05) from 60%WR max [557 ± 177(SD) ml/min; 56.0 ± 21.6 ml/min] to 80%WR max (679 ± 190 ml/min; 70.6 ± 24.8 ml/min), but no change was seen from 80%WR max to 100%WR max Blood velocity (49.5 ± 11.5 to 58.1 ± 11.6 cm/s) and brachial diameter (0.49 ± 0.05 to 0.50 ± 0.06 cm) showed concomitant increases ( P < 0.05) with blood flow from 60% to 80%WR max, whereas no differences were observed in a-vO 2diff Shear rate also increased ( P < 0.05) from 60% (822 ± 196 s -1 ) to 80% (951 ± 234 s -1 ) of WR max The mean response time (MRT) was slower ( P < 0.05) for blood flow (60%WR max 50 ± 22 s; 80%WR max 51 ± 20 s; 100%WR max 51 ± 23 s) than a-vO 2diff (60%WR max 29 ± 9 s; 80%WR max 29 ± 5 s; 100%WR max 20 ± 5 s), but not different from oxygen uptake (60%WR max 44 ± 25 s; 80%WR max 43 ± 14 s; 100%WR max 41 ± 32 s). No differences were observed in MRT for blood flow or oxygen uptake with increased exercise intensity. In conclusion, when approaching maximal intensity, oxygen uptake appeared to reach a critical level at ~80% of WR max and be regulated by blood flow. This implies that high, but not maximal, exercise intensity may be an optimal stimulus for shear stress-induced small muscle mass training adaptations. NEW & NOTEWORTHY This study evaluated blood flow regulation and oxygen uptake during small muscle mass forearm exercise with high to maximal intensity. Despite utilizing only a fraction of cardiac output, blood flow reached a plateau at 80% of maximal work rate and regulated peak oxygen uptake. Furthermore, the results revealed that muscle contractions dictated bulk oxygen delivery and yielded three times higher peak blood flow in the relaxation phase compared with mean values. Copyright © 2017 the American Physiological Society.

Development of a risk-screening tool for cancer survivors to participate in unsupervised moderate- to vigorous-intensity exercise: results from a survey study.

PubMed

Brown, Justin C; Ko, Emily M; Schmitz, Kathryn H

2015-02-01

The health benefits of exercise increase in dose-response fashion among cancer survivors. However, it is unclear how to identify cancer survivors who may require a pre-exercise evaluation before they progress from the common recommendation of walking to unsupervised moderate- to vigorous-intensity exercise. To clarify how to identify cancer survivors who should undergo a pre-exercise evaluation before they progress from the common recommendation of walking to unsupervised moderate- to vigorous-intensity exercise. Electronic survey. Forty-seven (n = 47) experts in the field of exercise physiology, rehabilitation medicine, and cancer survivorship. Not applicable. We synthesized peer-reviewed guidelines for exercise and cancer survivorship and identified 82 health factors that may warrant a pre-exercise evaluation before a survivor engages in unsupervised moderate- to vigorous-intensity exercise. The 82 health factors were classified into 3 domains: (1) clinical health factors; (2) comorbidity and device health factors; and (3) medications. We surveyed a sample of experts asking them to identify which of the 82 health factors among cancer survivors would indicate the need for a pre-exercise evaluation before they engaged in moderate- to vigorous-intensity exercise. The response rate to our survey was 75% (n = 47). Across the 3 domains of health factors, acute symptoms, comorbidities, and medications related to cardiovascular disease were agreed on to indicate a pre-exercise evaluation for survivors before they engaged in unsupervised moderate- to vigorous-intensity exercise. Other health factors in the survey included hematologic, musculoskeletal, systemic, gastrointestinal, pulmonary, and neurological symptoms and comorbidities. Eighteen experts (38%) said it was difficult to provide absolute answers because no 2 patients are alike, and their decisions are made on a case-by-case basis. The results from this expert survey will help to identify which cancer survivors should undergo a pre-exercise evaluation before they engage in unsupervised moderate- to vigorous-intensity exercise. Copyright © 2015 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

Study protocol for the FITR Heart Study: Feasibility, safety, adherence, and efficacy of high intensity interval training in a hospital-initiated rehabilitation program for coronary heart disease.

PubMed

Taylor, Jenna; Keating, Shelley E; Leveritt, Michael D; Holland, David J; Gomersall, Sjaan R; Coombes, Jeff S

2017-12-01

For decades, moderate intensity continuous training (MICT) has been the cornerstone of exercise prescription for cardiac rehabilitation (CR). High intensity interval training (HIIT) is now recognized in CR exercise guidelines as an appropriate and efficient modality for improving cardiorespiratory fitness, a strong predictor of mortality. However, the clinical application of HIIT in a real world CR setting, in terms of feasibility, safety, and long-term adherence, needs further investigation to address ongoing reservations. Furthermore, studies using objective measures of exercise intensity (such as heart rate; HR) have produced variable outcomes. Therefore we propose investigating the use of subjective measures (such as rating of perceived exertion (RPE)) for prescribing exercise intensity. One hundred adults with coronary artery disease (CAD) attending a hospital-initiated CR program will be randomized to 1) HIIT: 4 × 4 min high intensity intervals at 15-18 RPE interspersed with 3-min active recovery periods or 2) MICT: usual care exercise including 40 min continuous exercise at a moderate intensity corresponding to 11-13 RPE. Primary outcome is change in exercise capacity (peak VO 2 ) following 4 weeks of exercise training. Secondary outcome measures are: feasibility, safety, exercise adherence, body composition, vascular function, inflammatory markers, intrahepatic lipid, energy intake, and dietary behavior over 12-months; and visceral adipose tissue (VAT) following 12 weeks of exercise training. This study aims to address the ongoing concerns regarding the practicality and safety of HIIT in CR programs. We anticipate study findings will lead to the development of a standardized protocol to facilitate CR programs to incorporate HIIT as a standard exercise option for appropriate patients.

Assessment of Pulmonary Capillary Blood Volume, Membrane Diffusing Capacity, and Intrapulmonary Arteriovenous Anastomoses During Exercise.

PubMed

Tedjasaputra, Vincent; van Diepen, Sean; Collins, Sophie É; Michaelchuk, Wade M; Stickland, Michael K

2017-02-20

Exercise is a stress to the pulmonary vasculature. With incremental exercise, the pulmonary diffusing capacity (DLCO) must increase to meet the increased oxygen demand; otherwise, a diffusion limitation may occur. The increase in DLCO with exercise is due to increased capillary blood volume (Vc) and membrane diffusing capacity (Dm). Vc and Dm increase secondary to the recruitment and distension of pulmonary capillaries, increasing the surface area for gas exchange and decreasing pulmonary vascular resistance, thereby attenuating the increase in pulmonary arterial pressure. At the same time, the recruitment of intrapulmonary arteriovenous anastomoses (IPAVA) during exercise may contribute to gas exchange impairment and/or prevent large increases in pulmonary artery pressure. We describe two techniques to evaluate pulmonary diffusion and circulation at rest and during exercise. The first technique uses multiple-fraction of inspired oxygen (FIO2) DLCO breath holds to determine Vc and Dm at rest and during exercise. Additionally, echocardiography with intravenous agitated saline contrast is used to assess IPAVAs recruitment. Representative data showed that the DLCO, Vc, and Dm increased with exercise intensity. Echocardiographic data showed no IPAVA recruitment at rest, while contrast bubbles were seen in the left ventricle with exercise, suggesting exercise-induced IPAVA recruitment. The evaluation of pulmonary capillary blood volume, membrane diffusing capacity, and IPAVA recruitment using echocardiographic methods is useful to characterize the ability of the lung vasculature to adapt to the stress of exercise in health as well as in diseased groups, such as those with pulmonary arterial hypertension and chronic obstructive pulmonary disease.

Assessment of Pulmonary Capillary Blood Volume, Membrane Diffusing Capacity, and Intrapulmonary Arteriovenous Anastomoses During Exercise

PubMed Central

Tedjasaputra, Vincent; van Diepen, Sean; Collins, Sophie É; Michaelchuk, Wade M.; Stickland, Michael K.

2017-01-01

Exercise is a stress to the pulmonary vasculature. With incremental exercise, the pulmonary diffusing capacity (DLCO) must increase to meet the increased oxygen demand; otherwise, a diffusion limitation may occur. The increase in DLCO with exercise is due to increased capillary blood volume (Vc) and membrane diffusing capacity (Dm). Vc and Dm increase secondary to the recruitment and distension of pulmonary capillaries, increasing the surface area for gas exchange and decreasing pulmonary vascular resistance, thereby attenuating the increase in pulmonary arterial pressure. At the same time, the recruitment of intrapulmonary arteriovenous anastomoses (IPAVA) during exercise may contribute to gas exchange impairment and/or prevent large increases in pulmonary artery pressure. We describe two techniques to evaluate pulmonary diffusion and circulation at rest and during exercise. The first technique uses multiple-fraction of inspired oxygen (FIO2) DLCO breath holds to determine Vc and Dm at rest and during exercise. Additionally, echocardiography with intravenous agitated saline contrast is used to assess IPAVAs recruitment. Representative data showed that the DLCO, Vc, and Dm increased with exercise intensity. Echocardiographic data showed no IPAVA recruitment at rest, while contrast bubbles were seen in the left ventricle with exercise, suggesting exercise-induced IPAVA recruitment. The evaluation of pulmonary capillary blood volume, membrane diffusing capacity, and IPAVA recruitment using echocardiographic methods is useful to characterize the ability of the lung vasculature to adapt to the stress of exercise in health as well as in diseased groups, such as those with pulmonary arterial hypertension and chronic obstructive pulmonary disease. PMID:28287506

Creatine kinase response to high-intensity aerobic exercise in adult-onset muscular dystrophy.

PubMed

Andersen, Søren P; Sveen, Marie-Louise; Hansen, Regitze S; Madsen, Karen L; Hansen, Jonas B; Madsen, Mads; Vissing, John

2013-12-01

We investigated the effect of high-intensity exercise on plasma creatine kinase (CK) in patients with muscular dystrophies. Fourteen patients with Becker (BMD), facioscapulohumeral (FSHD), or limb-girdle type 2 (LGMD2) muscular dystrophy, and 8 healthy subjects performed 5 cycling tests: an incremental max test, and tests at 65%, 75%, 85%, and 95% of maximal oxygen uptake (VO2max ). Heart rate and oxygen consumption were measured during the tests, and plasma CK was measured before, immediately after, and 24 hours after exercise. All subjects were able to perform high-intensity exercise at the different levels. In patients with LGMD2 and FSHD, CK normalized 24 hours after exercise compared with the pre-exercise value, whereas those with BMD and healthy controls had elevated CK values 24 hours after exercise. The findings suggest that high-intensity exercise is generally well tolerated in patients with LGMD2 and FSHD, whereas those with BMD may be more prone to exercise-induced damage. Copyright © 2013 Wiley Periodicals, Inc.

Effects of Pilates Exercise on Salivary Secretory Immunoglobulin A Levels in Older Women.

PubMed

Hwang, Yoonyoung; Park, Jonghoon; Lim, Kiwon

2016-07-01

We examined the effects of a Pilates exercise program on the mucosal immune function in older women. The study population comprised 12 older women who were divided into a Pilates group (PG, n = 6) and a control group (CG, n = 6). Saliva samples were obtained from both groups before and after the experimental period for salivary secretory immunoglobulin A level measurement. In addition, acute high-intensity exercises were performed before and after the three-month Pilates exercise program. After three months, salivary flow was significantly higher in the PG than in the CG. After the acute high-intensity exercises were performed following the three-month Pilates exercise program, the salivary flow rate was significantly higher at all time points. The S-IgA secretion rate significantly increased 30 min after acute high-intensity exercise performed following the three-month Pilates exercise program. This study suggests that regular participation in a moderate-intensity Pilates exercise program can increase salivary flow rate and S-IgA secretion in older women.

Exercise-induced adaptations to white and brown adipose tissue.

PubMed

Lehnig, Adam C; Stanford, Kristin I

2018-03-07

The beneficial effects of exercise on skeletal muscle and the cardiovascular system have long been known. Recent studies have focused on investigating the effects of exercise on adipose tissue and the effects that these exercise-induced adaptations have on overall metabolic health. Examination of exercise-induced adaptations in both white adipose tissue (WAT) and brown adipose tissue (BAT) has revealed marked differences in each tissue with exercise. In WAT, there are changes to both subcutaneous WAT (scWAT) and visceral WAT (vWAT), including decreased adipocyte size and lipid content, increased expression of metabolic genes, altered secretion of adipokines and increased mitochondrial activity. Adaptations specific to scWAT include lipidomic remodeling of phospholipids and, in rodents, the beiging of scWAT. The changes to BAT are less clear: studies evaluating the effect of exercise on the BAT of humans and rodents have revealed contradictory data, making this an important area of current investigation. In this Review, we discuss the exercise-induced changes to WAT and BAT that have been reported by different studies and highlight the current questions in this field. © 2018. Published by The Company of Biologists Ltd.

Low- and high-intensity treadmill exercise attenuates chronic morphine-induced anxiogenesis and memory impairment but not reductions in hippocampal BDNF in female rats.

PubMed

Ghodrati-Jaldbakhan, Shahrbanoo; Ahmadalipour, Ali; Rashidy-Pour, Ali; Vafaei, Abbas Ali; Miladi-Gorji, Hossein; Alizadeh, Maryam

2017-05-15

Previous studies from our laboratory have shown that treadmill exercise alleviates the deficits in cognitive functions and anxiety behaviors induced by chronic exposure to morphine in male rats. In this study, we investigated the effects of low and high intensities of treadmill exercise on spatial memory, anxiety-like behaviors, and biochemical changes in the hippocampus and serum of morphine-treated female rats. The adult virgin female rats were injected with bi-daily doses (10mg/kg, at 12h intervals) of morphine over a period of 10days. Following these injections, the rats were exercised under low or high intensities for 30min per session on five days a week for four weeks. After exercise training, object location memory, anxiety profile, hippocampal BDNF, and serum corticosterone and BDNF were examined. Morphine-treated animals exhibited increased anxiety levels, impaired object location memory, and reduced hippocampal BDNF. Exercise alleviated these impairing effects on anxiety profile and memory but not hippocampal BDNF. The high-intensity exercise even further reduced the hippocampal BDNF. Additionally, both exercise regimens in the morphine group and the high exercise in the saline group reduced serum BDNF. Finally, the high-intensity exercise enhanced corticosterone serum. These findings indicate that the negative cognitive and behavioral effects of chronic exposure to morphine could be relieved by forced exercise in female rats. However, the exercise intensity is an important factor to be considered during exercise training. Finally, the correlation between changes of brain and serum BDNF and cognitive functions following morphine exposure needs further research. Copyright © 2017 Elsevier B.V. All rights reserved.

Exercise training modalities in chronic heart failure: does high intensity aerobic interval training make the difference?

PubMed

Giallauria, Francesco; Smart, Neil Andrew; Cittadini, Antonio; Vigorito, Carlo

2016-10-14

Exercise training (ET) is strongly recommended in patients with chronic heart failure (CHF). Moderate-intensity aerobic continuous ET is the best established training modality in CHF patients. In the last decade, however, high-intensity interval exercise training (HIIT) has aroused considerable interest in cardiac rehabilitation community. Basically, HIIT consists of repeated bouts of high-intensity exercise alternated with recovery periods. In CHF patients, HIIT exerts larger improvements in exercise capacity compared to moderate-continuous ET. These results are intriguing, mostly considering that better functional capacity translates into an improvement of symptoms and quality of life. Notably, HIIT did not reveal major safety issues; although CHF patients should be clinically stable, have had recent exposure to at least regular moderate-intensity exercise, and appropriate supervision and monitoring during and after the exercise session are mandatory. The impact of HIIT on cardiac dimensions and function and on endothelial function remains uncertain. HIIT should not replace other training modalities in heart failure but should rather complement them. Combining and tailoring different ET modalities according to each patient's baseline clinical characteristics (i.e. exercise capacity, personal needs, preferences and goals) seem the most astute approach to exercise prescription.

Dissimilar Physiological and Perceptual Responses Between Sprint Interval Training and High-Intensity Interval Training.

PubMed

Wood, Kimberly M; Olive, Brittany; LaValle, Kaylyn; Thompson, Heather; Greer, Kevin; Astorino, Todd A

2016-01-01

High-intensity interval training (HIIT) and sprint interval training (SIT) elicit similar cardiovascular and metabolic adaptations vs. endurance training. No study, however, has investigated acute physiological changes during HIIT vs. SIT. This study compared acute changes in heart rate (HR), blood lactate concentration (BLa), oxygen uptake (VO2), affect, and rating of perceived exertion (RPE) during HIIT and SIT. Active adults (4 women and 8 men, age = 24.2 ± 6.2 years) initially performed a VO2max test to determine workload for both sessions on the cycle ergometer, whose order was randomized. Sprint interval training consisted of 8 bouts of 30 seconds of all-out cycling at 130% of maximum Watts (Wmax). High-intensity interval training consisted of eight 60-second bouts at 85% Wmax. Heart rate, VO2, BLa, affect, and RPE were continuously assessed throughout exercise. Repeated-measures analysis of variance revealed a significant difference between HIIT and SIT for VO2 (p < 0.001), HR (p < 0.001), RPE (p = 0.03), and BLa (p = 0.049). Conversely, there was no significant difference between regimens for affect (p = 0.12). Energy expenditure was significantly higher (p = 0.02) in HIIT (209.3 ± 40.3 kcal) vs. SIT (193.5 ± 39.6 kcal). During HIIT, subjects burned significantly more calories and reported lower perceived exertion than SIT. The higher VO2 and lower BLa in HIIT vs. SIT reflected dissimilar metabolic perturbation between regimens, which may elicit unique long-term adaptations. If an individual is seeking to burn slightly more calories, maintain a higher oxygen uptake, and perceive less exertion during exercise, HIIT is the recommended routine.

Imagery use and affective responses during exercise: an examination of cerebral hemodynamics using near-infrared spectroscopy.

PubMed

Tempest, Gavin; Parfitt, Gaynor

2013-10-01

Imagery, as a cognitive strategy, can improve affective responses during moderate-intensity exercise. The effects of imagery at higher intensities of exercise have not been examined. Further, the effect of imagery use and activity in the frontal cortex during exercise is unknown. Using a crossover design (imagery and control), activity of the frontal cortex (reflected by changes in cerebral hemodynamics using near-infrared spectroscopy) and affective responses were measured during exercise at intensities 5% above the ventilatory threshold (VT) and the respiratory compensation point (RCP). Results indicated that imagery use influenced activity of the frontal cortex and was associated with a more positive affective response at intensities above VT, but not RCP to exhaustion (p < .05). These findings provide direct neurophysiological evidence of imagery use and activity in the frontal cortex during exercise at intensities above VT that positively impact affective responses.

Evidence for the involvement of the CXCL12 system in the adaptation of skeletal muscles to physical exercise.

PubMed

Puchert, Malte; Adams, Volker; Linke, Axel; Engele, Jürgen

2016-09-01

The chemokine CXCL12 and its primary receptor, CXCR4, not only promote developmental myogenesis, but also muscle regeneration. CXCL12 chemoattracts CXCR4-positive satellite cells/blood-borne progenitors to the injured muscle, promotes myoblast fusion, partially with existing myofibers, and induces angiogenesis in regenerating muscles. Interestingly, the mechanisms underlying muscle regeneration are in part identical to those involved in muscular adaptation to intensive physical exercise. These similarities now prompted us to determine whether physical exercise would impact the CXCL12 system in skeletal muscle. We found that CXCL12 and CXCR4 are upregulated in the gastrocnemius muscle of rats that underwent a four-week period of constrained daily running exercise on a treadmill. Double-staining experiments confirmed that CXCL12 and CXCR4 are predominantly expressed in MyHC-positive muscle fibers. Moreover, these training-dependent increases in CXCL12 and CXCR4 expression also occurred in rats with surgical coronary artery occlusion, implying that the muscular CXCL12 system is still active in skeletal myopathy resulting from chronic heart failure. Expression of the second CXCL12 receptor, CXCR7, which presumably acts as a scavenger receptor in muscle, was not affected by training. Attempts to dissect the molecular events underlying the training-dependent effects of CXCL12 revealed that the CXCL12-CXCR4 axis activates anabolic mTOR-p70S6K signaling and prevents upregulation of the catabolic ubiquitin ligase MurF-1 in C2C12 myotubes, eventually increasing myotube diameters. Together, these findings point to a pivotal role of the CXCL12-CXCR4 axis in exercise-induced muscle maintenance and/or growth. Copyright © 2016 Elsevier Inc. All rights reserved.

An Innovative Running Wheel-based Mechanism for Improved Rat Training Performance.

PubMed

Chen, Chi-Chun; Yang, Chin-Lung; Chang, Ching-Ping

2016-09-19

This study presents an animal mobility system, equipped with a positioning running wheel (PRW), as a way to quantify the efficacy of an exercise activity for reducing the severity of the effects of the stroke in rats. This system provides more effective animal exercise training than commercially available systems such as treadmills and motorized running wheels (MRWs). In contrast to an MRW that can only achieve speeds below 20 m/min, rats are permitted to run at a stable speed of 30 m/min on a more spacious and high-density rubber running track supported by a 15 cm wide acrylic wheel with a diameter of 55 cm in this work. Using a predefined adaptive acceleration curve, the system not only reduces the operator error but also trains the rats to run persistently until a specified intensity is reached. As a way to evaluate the exercise effectiveness, real-time position of a rat is detected by four pairs of infrared sensors deployed on the running wheel. Once an adaptive acceleration curve is initiated using a microcontroller, the data obtained by the infrared sensors are automatically recorded and analyzed in a computer. For comparison purposes, 3 week training is conducted on rats using a treadmill, an MRW and a PRW. After surgically inducing middle cerebral artery occlusion (MCAo), modified neurological severity scores (mNSS) and an inclined plane test were conducted to assess the neurological damages to the rats. PRW is experimentally validated as the most effective among such animal mobility systems. Furthermore, an exercise effectiveness measure, based on rat position analysis, showed that there is a high negative correlation between the effective exercise and the infarct volume, and can be employed to quantify a rat training in any type of brain damage reduction experiments.

Repeated high-intensity exercise in professional rugby union.

PubMed

Austin, Damien; Gabbett, Tim; Jenkins, David

2011-07-01

The aim of the present study was to describe the frequency, duration, and nature of repeated high-intensity exercise in Super 14 rugby union. Time-motion analysis was used during seven competition matches over the 2008 and 2009 Super 14 seasons; five players from each of four positional groups (front row forwards, back row forwards, inside backs, and outside backs) were assessed (20 players in total). A repeated high-intensity exercise bout was considered to involve three or more sprints, and/or tackles and/or scrum/ruck/maul activities within 21 s during the same passage of play. The range of repeated high-intensity exercise bouts for each group in a match was as follows: 11-18 for front row forwards, 11-21 for back row forwards, 13-18 for inside backs, and 2-11 for outside backs. The durations of the most intense repeated high-intensity exercise bouts for each position ranged from 53 s to 165 s and the minimum recovery periods between repeated high-intensity exercise bouts ranged from 25 s for the back row forwards to 64 s for the front row forwards. The present results show that repeated high-intensity exercise bouts vary in duration and activities relative to position but all players in a game will average at least 10 changes in activity in the most demanding bouts and complete at least one tackle and two sprints. The most intense periods of activity are likely to last as long as 120 s and as little as 25 s recovery may separate consecutive repeated high-intensity exercise bouts. The present findings can be used by coaches to prepare their players for the most demanding passages of play likely to be experienced in elite rugby union.

Blood lactate clearance after maximal exercise depends on active recovery intensity.

PubMed

Devlin, J; Paton, B; Poole, L; Sun, W; Ferguson, C; Wilson, J; Kemi, O J

2014-06-01

High-intensity exercise is time-limited by onset of fatigue, marked by accumulation of blood lactate. This is accentuated at maximal, all-out exercise that rapidly accumulates high blood lactate. The optimal active recovery intensity for clearing lactate after such maximal, all-out exercise remains unknown. Thus, we studied the intensity-dependence of lactate clearance during active recovery after maximal exercise. We constructed a standardized maximal, all-out treadmill exercise protocol that predictably lead to voluntary exhaustion and blood lactate concentration>10 mM. Next, subjects ran series of all-out bouts that increased blood lactate concentration to 11.5±0.2 mM, followed by recovery exercises ranging 0% (passive)-100% of the lactate threshold. Repeated measurements showed faster lactate clearance during active versus passive recovery (P<0.01), and that active recovery at 60-100% of lactate threshold was more efficient for lactate clearance than lower intensity recovery (P<0.05). Active recovery at 80% of lactate threshold had the highest rate of and shortest time constant for lactate clearance (P<0.05), whereas the response during the other intensities was graded (100%=60%>40%>passive recovery, P<0.05). Active recovery after maximal all-out exercise clears accumulated blood lactate faster than passive recovery in an intensity-dependent manner, with maximum clearance occurring at active recovery of 80% of lactate threshold.

Concluding remarks: nutritional strategies to support the adaptive response to prolonged exercise training.

PubMed

van Loon, Luc J C; Tipton, Kevin D

2013-01-01

Nutrition plays a key role in allowing the numerous training hours to be translated into useful adaptive responses of various tissues in the individual athlete. Research over the last decade has shown many examples of the impact of dietary interventions to modulate the skeletal muscle adaptive response to prolonged exercise training. Proper nutritional coaching should be applied throughout both training and competition, each with their specific requirements regarding nutrient provision. Such dietary support will improve exercise training efficiency and, as such, further increase performance capacity. Here, we provide an overview on the properties of various nutritional interventions that may be useful to support the adaptive response to exercise training and competition and, as such, to augment exercise training efficiency. Copyright © 2013 Nestec Ltd., Vevey/S. Karger AG, Basel.

Impact-Induced Muscle Damage and Contact-Sport: Aetiology, Effects on Neuromuscular Function and Recovery, and the Modulating Effects of Adaptation and Recovery Strategies.

PubMed

Naughton, Mitchell; Miller, Joanna; Slater, Gary J

2017-11-28

Athletes involved in contact-sports are habitually exposed to skeletal muscle damage as part of their training and performance environments. This often leads to exercise-induced muscle damage (EIMD) resulting from repeated eccentric and/or high-intensity exercise, and impact-induced muscle damage (IIMD) resulting from collisions with opponents and the playing surface. Whilst EIMD has been an area of extensive investigation, IIMD has received comparatively little research, with the magnitude and timeframe of alterations following IIMD not presently well understood. It is currently thought that EIMD occurs through an overload of mechanical stress causing ultrastructural damage to the cellular membrane constituents. Damage leads to compromised ability to produce force which manifest immediately and persist for up to 14 days following exercise exposure. IIMD has been implicated in attenuated neuromuscular performance and recovery with inflammatory process implicated, although the underlying time course remains unclear. Exposure to EIMD leads to an adaptation to subsequent exposures, a phenomenon known as the repeated-bout effect. An analogous adaptation has been suggested to occur following IIMD, however, to date this contention remains equivocal. Whilst a considerable body of research has explored the efficacy of recovery strategies following EIMD, strategies promoting recovery from IIMD are limited to investigations using animal contusion models. Strategies such as cryotherapy and antioxidant supplementation, which focus on attenuating the secondary inflammatory response may provide additional benefit in IIMD and are explored herein. Further research is required to firstly establish a model of generating IIMD and then explore broader areas around IIMD in athletic populations.

Two years of combined high-intensity physical training and heat acclimatization affect lymphocyte and serum HSP70 in purebred military working dogs.

PubMed

Bruchim, Yaron; Aroch, Itamar; Eliav, Ady; Abbas, Atallah; Frank, Ilan; Kelmer, Efrat; Codner, Carolina; Segev, Gilad; Epstein, Yoram; Horowitz, Michal

2014-07-15

Military working dogs in hot countries undergo exercise training at high ambient temperatures for at least 9 mo annually. Physiological adaptations to these harsh conditions have been extensively studied; however, studies focusing on the underlying molecular adaptations are limited. In the current study, military working dogs were chosen as a model to examine the effects of superimposing endurance exercise on seasonal acclimatization to environmental heat stress. The lymphocyte HSP70 profile and extracellular HSP70 were studied in tandem with physiological performance in the dogs from their recruitment for the following 2 yr. Aerobic power and heat shock proteins were measured at the end of each summer, with physical performance tests (PPTs) in an acclimatized room (22°C). The study shows that together with a profound enhancement of aerobic power and physical performance, hsp72 mRNA induction immediately post-PPT and 45 min later, progressively increased throughout the study period (relative change in median lymphocyte hsp72 mRNA first PPT, 4.22 and 12.82; second PPT, 17.19 and 109.05, respectively), whereas induction of HSP72 protein was stable. These responses suggest that cellular/molecular adaptive tools for maintaining HSP72 homeostasis exist. There was also a significant rise in basal and peak median optical density extracellular HSP at the end of each exercise test (first PPT, 0.13 and 0.15; second PPT, 1.04 and 1.52, respectively). The relationship between these enhancements and improved aerobic power capacity is not yet fully understood. Copyright © 2014 the American Physiological Society.

Effects of inspiratory muscle training on respiratory muscle electromyography and dyspnea during exercise in healthy men.

PubMed

Ramsook, Andrew H; Molgat-Seon, Yannick; Schaeffer, Michele R; Wilkie, Sabrina S; Camp, Pat G; Reid, W Darlene; Romer, Lee M; Guenette, Jordan A

2017-05-01

Inspiratory muscle training (IMT) has consistently been shown to reduce exertional dyspnea in health and disease; however, the physiological mechanisms remain poorly understood. A growing body of literature suggests that dyspnea intensity can be explained largely by an awareness of increased neural respiratory drive, as measured indirectly using diaphragmatic electromyography (EMGdi). Accordingly, we sought to determine whether improvements in dyspnea following IMT can be explained by decreases in inspiratory muscle electromyography (EMG) activity. Twenty-five young, healthy, recreationally active men completed a detailed familiarization visit followed by two maximal incremental cycle exercise tests separated by 5 wk of randomly assigned pressure threshold IMT or sham control (SC) training. The IMT group ( n = 12) performed 30 inspiratory efforts twice daily against a 30-repetition maximum intensity. The SC group ( n = 13) performed a daily bout of 60 inspiratory efforts against 10% maximal inspiratory pressure (MIP), with no weekly adjustments. Dyspnea intensity was measured throughout exercise using the modified 0-10 Borg scale. Sternocleidomastoid and scalene EMG was measured using surface electrodes, whereas EMGdi was measured using a multipair esophageal electrode catheter. IMT significantly improved MIP (pre: -138 ± 45 vs. post: -160 ± 43 cmH 2 O, P < 0.01), whereas the SC intervention did not. Dyspnea was significantly reduced at the highest equivalent work rate (pre: 7.6 ± 2.5 vs. post: 6.8 ± 2.9 Borg units, P < 0.05), but not in the SC group, with no between-group interaction effects. There were no significant differences in respiratory muscle EMG during exercise in either group. Improvements in dyspnea intensity ratings following IMT in healthy humans cannot be explained by changes in the electrical activity of the inspiratory muscles. NEW & NOTEWORTHY Exertional dyspnea intensity is thought to reflect an increased awareness of neural respiratory drive, which is measured indirectly using diaphragmatic electromyography (EMGdi). We examined the effects of inspiratory muscle training (IMT) on dyspnea, EMGdi, and EMG of accessory inspiratory muscles. IMT significantly reduced submaximal dyspnea intensity ratings but did not change EMG of any inspiratory muscles. Improvements in exertional dyspnea following IMT may be the result of nonphysiological factors or physiological adaptations unrelated to neural respiratory drive. Copyright © 2017 the American Physiological Society.

Effects of inspiratory muscle training on respiratory muscle electromyography and dyspnea during exercise in healthy men

PubMed Central

Molgat-Seon, Yannick; Schaeffer, Michele R.; Wilkie, Sabrina S.; Camp, Pat G.; Reid, W. Darlene; Romer, Lee M.

2017-01-01

Inspiratory muscle training (IMT) has consistently been shown to reduce exertional dyspnea in health and disease; however, the physiological mechanisms remain poorly understood. A growing body of literature suggests that dyspnea intensity can be explained largely by an awareness of increased neural respiratory drive, as measured indirectly using diaphragmatic electromyography (EMGdi). Accordingly, we sought to determine whether improvements in dyspnea following IMT can be explained by decreases in inspiratory muscle electromyography (EMG) activity. Twenty-five young, healthy, recreationally active men completed a detailed familiarization visit followed by two maximal incremental cycle exercise tests separated by 5 wk of randomly assigned pressure threshold IMT or sham control (SC) training. The IMT group (n = 12) performed 30 inspiratory efforts twice daily against a 30-repetition maximum intensity. The SC group (n = 13) performed a daily bout of 60 inspiratory efforts against 10% maximal inspiratory pressure (MIP), with no weekly adjustments. Dyspnea intensity was measured throughout exercise using the modified 0–10 Borg scale. Sternocleidomastoid and scalene EMG was measured using surface electrodes, whereas EMGdi was measured using a multipair esophageal electrode catheter. IMT significantly improved MIP (pre: −138 ± 45 vs. post: −160 ± 43 cmH2O, P < 0.01), whereas the SC intervention did not. Dyspnea was significantly reduced at the highest equivalent work rate (pre: 7.6 ± 2.5 vs. post: 6.8 ± 2.9 Borg units, P < 0.05), but not in the SC group, with no between-group interaction effects. There were no significant differences in respiratory muscle EMG during exercise in either group. Improvements in dyspnea intensity ratings following IMT in healthy humans cannot be explained by changes in the electrical activity of the inspiratory muscles. NEW & NOTEWORTHY Exertional dyspnea intensity is thought to reflect an increased awareness of neural respiratory drive, which is measured indirectly using diaphragmatic electromyography (EMGdi). We examined the effects of inspiratory muscle training (IMT) on dyspnea, EMGdi, and EMG of accessory inspiratory muscles. IMT significantly reduced submaximal dyspnea intensity ratings but did not change EMG of any inspiratory muscles. Improvements in exertional dyspnea following IMT may be the result of nonphysiological factors or physiological adaptations unrelated to neural respiratory drive. PMID:28255085

Cardiac Remodeling in Response to 1 Year of Intensive Endurance Training

PubMed Central

Arbab-Zadeh, Armin; Perhonen, Merja; Howden, Erin; Peshock, Ronald M.; Zhang, Rong; Adams-Huet, Beverly; Haykowsky, Mark J.; Levine, Benjamin D.

2017-01-01

Background It is unclear whether, and to what extent, the striking cardiac morphological manifestations of endurance athletes are a result of exercise training or a genetically determined characteristic of talented athletes. We hypothesized that prolonged and intensive endurance training in previously sedentary healthy young individuals could induce cardiac remodeling similar to that observed cross-sectionally in elite endurance athletes. Methods and Results Twelve previously sedentary subjects (aged 29±6 years; 7 men and 5 women) trained progressively and intensively for 12 months such that they could compete in a marathon. Magnetic resonance images for assessment of right and left ventricular mass and volumes were obtained at baseline and after 3, 6, 9, and 12 months of training. Maximum oxygen uptake (V̇o2 max) and cardiac output at rest and during exercise (C2H2 rebreathing) were measured at the same time periods. Pulmonary artery catheterization was performed before and after 1 year of training, and pressure-volume and Starling curves were constructed during decreases (lower body negative pressure) and increases (saline infusion) in cardiac volume. Mean V̇o2 max rose from 40.3±1.6 to 48.7±2.5 mL/kg per minute after 1 year (P<0.00001), associated with an increase in both maximal cardiac output and stroke volume. Left and right ventricular mass increased progressively with training duration and intensity and reached levels similar to those observed in elite endurance athletes. In contrast, left ventricular volume did not change significantly until 6 months of training, although right ventricular volume increased progressively from the outset; Starling and pressure-volume curves approached but did not match those of elite athletes. Conclusions One year of prolonged and intensive endurance training leads to cardiac morphological adaptations in previously sedentary young subjects similar to those observed in elite endurance athletes; however, it is not sufficient to achieve similar levels of cardiac compliance and performance. Contrary to conventional thinking, the left ventricle responds to exercise with initial concentric but not eccentric remodeling during the first 6 to 9 months after commencement of endurance training depending on the duration and intensity of exercise. Thereafter, the left ventricle dilates and restores the baseline mass-to-volume ratio. In contrast, the right ventricle responds to endurance training with eccentric remodeling at all levels of training. PMID:25281664

Effect of exercise intensity on albuminuria in adolescents with Type 1 diabetes mellitus.

PubMed

Kornhauser, C; Malacara, J-M; Macías-Cervantes, M-H; Rivera-Cisneros, A-E

2012-01-01

Exercise may be useful to detect patients with diabetes prone to develop persistent microalbuminuria. We studied the relationship between exercise intensity, measured as maximal oxygen consumption (VO(2)max), and microalbuminuria in patients with Type 1 diabetes mellitus patients. We studied 10 patients, age range 10-18 years, with Type 1 diabetes who were normotensive and normoalbuminuric, with less than 10 years since diagnosis. Patients had normal renal function, without infections or clinical evidence of complications. Metabolic control was intensively adjusted in all patients. They underwent three consecutive physical exercise tests, reaching 100, 80 and 60% of the maximal cardiac frequency response. Eight patients had adequate to regular metabolic control. All patients had lower than predicted VO(2)max values. At 60%, only three patients showed microalbuminuria in excess of 20 μg/min, two of them had inadequate metabolic control. Post-exercise microalbuminuria exceeded normal values in nine, seven and three patients when submitted to 100, 80 and 60% of exercise intensity, respectively. Microalbuminuria increased with exercise intensity. Sex, body composition and VO(2)max were the main factors associated with microalbuminuria. The prognostic significance of albuminuria induced by intense exercise in these subjects with Type 1 diabetes is not yet known. © 2011 The Authors. Diabetic Medicine © 2011 Diabetes UK.

Morning bright light exposure has no influence on self-chosen exercise intensity and mood in overweight individuals - A randomized controlled trial.

PubMed

Knaier, Raphael; Klenk, Christopher; Königstein, Karsten; Hinrichs, Timo; Rossmeissl, Anja; Infanger, Denis; Cajochen, Christian; Schmidt-Trucksäss, Arno

2018-04-01

Overweight is a worldwide increasing public health issue. Physical exercise is a useful countermeasure. Overweight individuals choose rather low exercise intensities, but especially high exercise intensities lead to higher energy expenditure and show beneficial health effects compared to lower exercise intensities. However, especially in the morning higher exercise intensities are likely to be avoided due to higher subjective effort. Bright light exposure has shown to increase maximum performance. The aim of this study was to investigate if bright light exposure can also increase self-chosen exercise intensity. We hypothesized that morning bright light exposure increases self-chosen exercise intensity of subsequent exercise through increased mood and reduced sleepiness in overweight individuals. In this randomized controlled single-blind parallel group design, 26 overweight individuals (11 males, 15 females; age 25 ± 5.7 years; body mass index 28.9 ± 2.1 kg/m 2 ) underwent three measurement appointments. On the first appointment, subjects performed a cardiopulmonary exercise test to measure maximum oxygen uptake (VO2max). Two days later a 30-min exercise session with self-chosen exercise intensity was performed for familiarization. Then subjects were randomly allocated to bright light (~4400 lx) or a control light (~230 lx) condition. Three to seven days later, subjects were exposed to light for 30 min starting at 8:00 am, immediately followed by a 30-min exercise session with persisting light exposure. Multidimensional mood questionnaires were filled out before and after the light exposure and after the exercise session. The primary outcome was the mean power output during the exercise session and the secondary outcome the rating on the three domains (i.e. good-bad; awake-tired; calm-nervous) of the multidimensional mood questionnaire. Mean power output during the exercise session was 92 ± 19 W in bright light and 80 ± 37 W in control light, respectively. In the multivariate analysis adjusted for VO2max, the mean power output during the exercise session was 8.5 W higher (95% confidence interval -12.7, 29.7; p = 0.416) for participants in bright light compared to control light. There were no significant differences between the groups for any of the three domains of the questionnaire at any time point. This is in contrast to longer lasting intervention studies that show positive influences on mood and suggests that bright light therapy requires repetitive sessions to improve mood in overweight individuals. In conclusion bright light exposure does not acutely increase self-chosen exercise intensity or improve mood in a 30-min exercise session starting at 08:30. However, regarding the fact that overweight is a worldwide and rapidly increasing public health issue even small increases in exercise intensity may be relevant. The trend toward superiority of bright light over control light implicates that further studies may be conducted in a larger scale. VO2max: maximum oxygen uptake; 95% CI: 95% confidence interval; SD: standard deviation.

Attentional bias to emotional stimuli is altered during moderate- but not high-intensity exercise.

PubMed

Tian, Qu; Smith, J Carson

2011-12-01

Little is known regarding how attention to emotional stimuli is affected during simultaneously performed exercise. Attentional biases to emotional face stimuli were assessed in 34 college students (17 women) using the dot-probe task during counterbalanced conditions of moderate- (heart rate at 45% peak oxygen consumption) and high-intensity exercise (heart rate at 80% peak oxygen consumption) compared with seated rest. The dot-probe task consisted of 1 emotional face (pleasant or unpleasant) paired with a neutral face for 1,000 ms; 256 trials (128 trials for each valence) were presented during each condition. Each condition lasted approximately 10 min. Participants were instructed to perform each trial of the dot-probe task as quickly and accurately as possible during the exercise and rest conditions. During moderate-intensity exercise, participants exhibited significantly greater attentional bias scores to pleasant compared with unpleasant faces (p < .01), whereas attentional bias scores to emotional faces did not differ at rest or during high-intensity exercise (p > .05). In addition, the attentional bias to unpleasant faces was significantly reduced during moderate-intensity exercise compared with that during rest (p < .05). These results provide behavioral evidence that during exercise at a moderate intensity, there is a shift in attention allocation toward pleasant emotional stimuli and away from unpleasant emotional stimuli. Future work is needed to determine whether acute exercise may be an effective treatment approach to reduce negative bias or enhance positive bias in individuals diagnosed with mood or anxiety disorders, or whether attentional bias during exercise predicts adherence to exercise. (c) 2011 APA, all rights reserved.

Effects of High-Intensity Training on Anaerobic and Aerobic Contributions to Total Energy Release During Repeated Supramaximal Exercise in Obese Adults.

PubMed

Jabbour, Georges; Iancu, Horia-Daniel; Paulin, Anne

Studying relative anaerobic and aerobic metabolism contributions to total energy release during exercise may be valuable in understanding exercise energetic demands and the energetic adaptations that occur in response to acute or chronic exercise in obese adults. The aim of the present study is to evaluate the effects of 6 weeks of high-intensity training (HIT) on relative anaerobic and aerobic contributions to total energy release and on peak power output during repeated supramaximal cycling exercises (SCE) in obese adults. Twenty-four obese adults (body mass index = ± 33 kg.m -2 ) were randomized into a control group ( n  = 12) and an HIT group ( n  = 12). Accumulated oxygen deficits (ml.min -1 ) and anaerobic and aerobic contributions (%) were measured in all groups before and after training via repeated SCE. In addition, the peak power output performed during SCE was determined using the force-velocity test. Before HIT, anaerobic contributions to repeated SCE did not differ between the groups and decreased significantly during the third and fourth repetitions. After HIT, anaerobic contributions increased significantly in the HIT group (+11 %, p  < 0.01) and were significantly higher than those of the control group ( p  < 0.01). Moreover, the peak power obtained during SCE increased significantly in the HIT group (+110 W.kg -1 , p  < 0.01) and correlated positively with increases in anaerobic contributions ( r  = 0.9, p  < 0.01). In obese adults, HIT increased anaerobic contributions to energy release which were associated with peak power enhancement in response to repeated SCE. Consequently, HIT may be an appropriate approach for improving energy contributions and muscle power among obese adults.

Determination of Strength Exercise Intensities Based on the Load-Power-Velocity Relationship

PubMed Central

Jandačka, Daniel; Beremlijski, Petr

2011-01-01

The velocity of movement and applied load affect the production of mechanical power output and subsequently the extent of the adaptation stimulus in strength exercises. We do not know of any known function describing the relationship of power and velocity and load in the bench press exercise. The objective of the study is to find a function modeling of the relationship of relative velocity, relative load and mechanical power output for the bench press exercise and to determine the intensity zones of the exercise for specifically focused strength training of soccer players. Fifteen highly trained soccer players at the start of a competition period were studied. The subjects of study performed bench presses with the load of 0, 10, 30, 50, 70 and 90% of the predetermined one repetition maximum with maximum possible speed of movement. The mean measured power and velocity for each load (kg) were used to develop a multiple linear regression function which describes the quadratic relationship between the ratio of power (W) to maximum power (W) and the ratios of the load (kg) to one repetition maximum (kg) and the velocity (m•s−1) to maximal velocity (m•s−1). The quadratic function of two variables that modeled the searched relationship explained 74% of measured values in the acceleration phase and 75% of measured values from the entire extent of the positive power movement in the lift. The optimal load for reaching maximum power output suitable for the dynamics effort strength training was 40% of one repetition maximum, while the optimal mean velocity would be 75% of maximal velocity. Moreover, four zones: maximum power, maximum velocity, velocity-power and strength-power were determined on the basis of the regression function. PMID:23486484

Determination of strength exercise intensities based on the load-power-velocity relationship.

PubMed

Jandačka, Daniel; Beremlijski, Petr

2011-06-01

The velocity of movement and applied load affect the production of mechanical power output and subsequently the extent of the adaptation stimulus in strength exercises. We do not know of any known function describing the relationship of power and velocity and load in the bench press exercise. The objective of the study is to find a function modeling of the relationship of relative velocity, relative load and mechanical power output for the bench press exercise and to determine the intensity zones of the exercise for specifically focused strength training of soccer players. Fifteen highly trained soccer players at the start of a competition period were studied. The subjects of study performed bench presses with the load of 0, 10, 30, 50, 70 and 90% of the predetermined one repetition maximum with maximum possible speed of movement. The mean measured power and velocity for each load (kg) were used to develop a multiple linear regression function which describes the quadratic relationship between the ratio of power (W) to maximum power (W) and the ratios of the load (kg) to one repetition maximum (kg) and the velocity (m•s(-1)) to maximal velocity (m•s(-1)). The quadratic function of two variables that modeled the searched relationship explained 74% of measured values in the acceleration phase and 75% of measured values from the entire extent of the positive power movement in the lift. The optimal load for reaching maximum power output suitable for the dynamics effort strength training was 40% of one repetition maximum, while the optimal mean velocity would be 75% of maximal velocity. Moreover, four zones: maximum power, maximum velocity, velocity-power and strength-power were determined on the basis of the regression function.

Exercise training guidelines for the elderly.

PubMed

Evans, W J

1999-01-01

The capacity of older men and women to adapt to increased levels of physical activity is preserved, even in the most elderly. Aerobic exercise results in improvements in functional capacity and reduced risk of developing Type II diabetes in the elderly. High-intensity resistance training (above 60% of the one repetition maximum) has been demonstrated to cause large increases in strength in the elderly. In addition, resistance training result in significant increases in muscle size in elderly men and women. Resistance training has also been shown to significantly increase energy requirements and insulin action of the elderly. We have recently demonstrated that resistance training has a positive effect on multiple risk factors for osteoporotic fracture in previously sedentary postmenopausal women. Because the sedentary lifestyle of a long-term care facility may exacerbate losses of muscle function, we have applied this same training program to frail, institutionalized elderly men and women. In a population of 100 nursing home residents, a randomly assigned high-intensity strength-training program resulted in significant gains in strength and functional status. In addition, spontaneous activity, measured by activity monitors, increased significantly in those participating in the exercise program whereas there was no change in the sedentary control group. Before the strength training intervention, the relationship of whole body potassium and leg strength was seen to be relatively weak (r2 = 0.29, P < 0.001), indicating that in the very old, muscle mass is an important but not the only determining factor of functional status. Thus, exercise may minimize or reverse the syndrome of physical frailty, which is so prevalent among the most elderly. Because of their low functional status and high incidence of chronic disease, there is no segment of the population that can benefit more from exercise than the elderly.

Caffeine prevents changes in muscle caused by high-intensity interval training.

PubMed

Vieira, Juliano M; Gutierres, Jessié M; Carvalho, Fabiano B; Pereira, Luciane B; Oliveira, Liziele S; Morsch, Vera Maria; Schetinger, Maria Rosa C; Rodrigues, Marília V; Leitemperger, Jossiele; Loro, Vânia; Krewer, Cristina C; Vencato, Marina S; Spanevello, Roselia M

2017-05-01

The use of ergogenic substances such as caffeine has become a strategy to enhance sports performance. In the present study we evaluated the effects of high-intensity interval training (HIIT) associated with caffeine intake on acetylcholinesterase (AChE) and Ca 2+ ATPase activity and glycogen levels in the muscles of rats were evaluated. The animals were divided in groups: control, caffeine 4 or 8mg/kg, HIIT, HIIT plus caffeine 4 or caffeine 8mg/kg. Our results showed a decrease in glycogen levels in muscle in all trained groups after acute session exercise, while that an increase in glycogen levels was observed in all groups in relation to control in chronic exercise protocol. HIIT increases the thickness of the left ventricle and the Ca 2+ -ATPase activity and decrease the AChE activity in gastrocnemius muscle. Caffeine treatment prevents changes in enzymes activities as well as left ventricular hypertrophy adaptation induced by HIIT. Our findings suggest that caffeine modulates crucial pathways for muscle contraction in HIIT. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Effects of exercise at individual anaerobic threshold and maximal fat oxidation intensities on plasma levels of nesfatin-1 and metabolic health biomarkers.

PubMed

Mohebbi, Hamid; Nourshahi, Maryam; Ghasemikaram, Mansour; Safarimosavi, Saleh

2015-03-01

Exercise is recognized as an effective method of weight management and short-term appetite regulation tool. The effect of different exercise intensities on appetite regulation hormones in healthy overweight participants has not been intensively studied. The aim of this study was to examine the influence of exercise at individual anaerobic threshold (IAT) and maximal fat oxidation (Fatmax) intensities on the nesfatin-1 response and metabolic health biomarkers in overweight men. Nine healthy overweight males (age, 23.1 ± 1.1 years) volunteered in this study in a counterbalanced order. Blood samples were obtained before, immediately after, and following the first 45 min of recovery for measuring plasma variables. There was significant decrease in plasma levels of nesfatin-1 and leptin after exercise at the IAT intensity which remained lower than baseline following 45 min of recovery. However, nesfatin-1 and leptin levels did not change significantly in any time courses of Fatmax intensity (P > 0.09). Plasma interleukin-6 (IL-6) concentration increased during exercise in both intensities (P < 0.05), whereas changes in free fatty acids (FFAs) and epinephrine concentrations were significant only at the IAT. In addition, a significant correlation was found among nesfatin-1 levels with insulin (r = 0.39, P < 0.05) and glucose (r = 0.41, P < 0.05) at basal and in response to exercise. These results indicate that IAT has a greater exercise-induced appetite regulation effect compared with Fat(max). Based on these data, the intensity of exercise may have an important role in changes of nesfatin-1, leptin, FFA, and epinephrine concentrations even though this was not the case for IL-6 and insulin resistance.

Effect of exercise intensity and mode on acute appetite control in men and women.

PubMed

Panissa, Valéria Leme Gonçalves; Julio, Ursula Ferreira; Hardt, Felipe; Kurashima, Carolina; Lira, Fábio Santos; Takito, Monica Yuri; Franchini, Emerson

2016-07-07

The aim of this study was to compare the effects of exercise intensity on appetite control: relative energy intake (energy intake minus the energy expenditure of exercise; REI), hunger scores, and appetite-regulating hormones in men and women. Eleven men and 9 women were submitted to 4 experimental sessions: high-intensity intermittent all-out exercise (HIIE-A) for 60 × 8 s interspersed by 12 s of passive recovery; high-intensity intermittent exercise (HIIE) at 100% of maximal load attained in incremental test; steady-state exercise at 60% of maximal load, matched by work done; and a control session. Exercise was performed 1.5 h after a standardized breakfast, and an ad libitum lunch was offered 4 h after breakfast. Blood concentration of insulin, cortisol, acylated ghrelin, peptideYY 3-36 , glucose, and hunger scores were measured when fasting, and at 1.5, 2, 3.25, and 4 h of experiment. REI was lower in all exercises than in the control, without differences between exercises and sex showing no compensation in energy intake because of any exercise; the hunger scores were lower only in the exercises performed at higher intensity (HIIE and HIIE-A) compared with the control. The area under the curve of acylated ghrelin was lower in the HIIE-A when compared with the control. PeptideYY 3-36 was higher in men than women and cortisol higher in women than men independently of the condition. Although high-intensity exercises promoted a little more pronounced effects in the direction of suppressing the appetite, no differences were observed in REI, demonstrating that these modifications were not sufficient to affect energy intake.

Does Short-Duration Heat Exposure at a Matched Cardiovascular Intensity Improve Intermittent-Running Performance in a Cool Environment?

PubMed

Philp, Calvin P; Buchheit, Martin; Kitic, Cecilia M; Minson, Christopher T; Fell, James W

2017-07-01

To investigate whether a 5-d cycling training block in the heat (35°C) in Australian Rules footballers was superior to exercising at the same relative intensity in cool conditions (15°C) for improving intermittent-running performance in a cool environment (<18°C). Using a parallel-group design, 12 semiprofessional football players performed 5 d of cycling exercise (70% heart-rate reserve [HRR] for 45 min [5 × 50-min sessions in total]) in a hot (HEAT, 35°C ± 1°C, 56% ± 9% RH) or cool environment (COOL, 15°C ± 3°C, 81% ± 10% RH). A 30-15 Intermittent Fitness Test to assess intermittent running performance (V IFT ) was conducted in a cool environment (17°C ± 2°C, 58 ± 5% RH) before and twice after (1 and 3 d) the intervention. There was a likely small increase in V IFT in each group (HEAT, 0.5 ± 0.3 km/h, 1.5 ± 0.8 × smallest worthwhile change [SWC]; COOL, 0.4 ± 0.4 km/h, 1.6 ± 1.2 × SWC) 3 d postintervention, with no difference in change between the groups (0.5% ± 1.9%, 0.4 ± 1.4 × SWC). Cycle power output during the intervention was almost certainly lower in the HEAT group (HEAT 1.8 ± 0.2 W/kg vs COOL 2.5 ± 0.3 W/kg, -21.7 ± 3.2 × SWC, 100/0/0). When cardiovascularexercise intensity is matched (ie, 70% HRR) between environmental conditions, there is no additional performance benefit from short-duration moderate-intensity heat exposure (5 × 50 min) for semiprofessional footballers exercising in cool conditions. However, the similar positive adaptations may occur in HEAT with 30% lower mechanical load, which may be of interest for load management during intense training or rehabilitation phases.

Exhaustive submaximal endurance and resistance exercises induce temporary immunosuppression via physical and oxidative stress

PubMed Central

Jin, Chan-Ho; Paik, Il-Young; Kwak, Yi-Sub; Jee, Yong-Seok; Kim, Joo-Young

2015-01-01

Regular running and strength training are the best ways to improve aerobic capacity and develop the size of skeletal muscles. However, uncontrolled physical activities can often lead to an undertraining or over-training syndrome. In particular, overtraining causes persistent fatigue and reduces physical performance due to changes in the various physiological and immunological factors. In this study, we gave an exhaustive submaximal endurance or resistance exercise to participants and investigated the relationship between physical stress (cortisol level in blood), oxidative stress (intracellular ROS accumulation), and adaptive immune response (CD4:CD8 ratio). Materials and Methods Ten male volunteers were recruited, and performed a submaximal endurance or resistance exercise with 85% of VO2max or 1-repetition maximum until exhaustion. Blood samples were collected at rest, and at 0 and 30 min after the exercise. Cortisol levels, oxidative stress, and immune cell phenotypes in peripheral blood were evaluated. Cortisol levels in the sera increased after the exhaustive endurance and resistance exercises and such increments were maintained through the recovery. Intra-cellular ROS levels also increased after the exhaustive endurance and resistance exercises. The ratio of CD4+ T cells to CD8+ T cells after each type of submaximal exercise decreased compared with that at the resting stage, and returned to the resting level at 30 min after the exercise. In this study, an exhaustive endurance or a resistance exercise with submaximal intensity caused excessive physical stress, intra-cellular oxidative stress, and post-exercise immunosuppression. This result suggests that excessive physical stress induced temporary immune dysfunction via physical and oxidative stress. PMID:26331134

Growth hormone-insulin-like growth factor-1 and inflammatory response to a single exercise bout in children and adolescents.

PubMed

Nemet, Dan; Eliakim, Alon

2010-01-01

Physical activity plays an important role in tissue anabolism, growth and development, but the mechanisms that link patterns of exercise with tissue anabolism are not completely understood. The effectiveness of physical training depends on the training load and on the individual ability to tolerate it, and an imbalance between the two may lead to under or over-training. Therefore, many efforts have been made to find objective parameters to quantify the balance between training load and the athlete's tolerance. One of the unique features of exercise is that it leads to a simultaneous increase of antagonistic mediators. On the one hand, exercise stimulates anabolic components of the growth hormone (GH) → IGF-1 (insulin-like growth factor-1) axis. On the other hand, exercise elevates catabolic pro-inflammatory cytokines such as interleukin-6 (IL-6), IL-1 and tumor necrosis factor-α (TNF-α). This emphasizes probably the importance of optimal adaptation to exercise in particularly during adolescence. The very fine balance between the anabolic and inflammatory/catabolic response to exercise will determine the effectiveness of exercise training and the health consequences of exercise. If the anabolic response is stronger, exercise will probably lead ultimately to increased muscle mass and improved fitness. A greater catabolic response, in particularly if persists for long duration, may lead to overtraining. Therefore, changes in the anabolic-catabolic hormonal balance and in circulating inflammatory cytokines can be used by adolescent athletes and/or their coaches to gauge the training intensity in individual and team sports. Copyright © 2010 S. Karger AG, Basel.

Functional electrical stimulation: cardiorespiratory adaptations and applications for training in paraplegia.

PubMed

Deley, Gaëlle; Denuziller, Jérémy; Babault, Nicolas

2015-01-01

Regular exercise can be broadly beneficial to health and quality of life in humans with spinal cord injury (SCI). However, exercises must meet certain criteria, such as the intensity and muscle mass involved, to induce significant benefits. SCI patients can have difficulty achieving these exercise requirements since the paralysed muscles cannot contribute to overall oxygen consumption. One solution is functional electrical stimulation (FES) and, more importantly, hybrid training that combines volitional arm and electrically controlled contractions of the lower limb muscles. However, it might be rather complicated for therapists to use FES because of the wide variety of protocols that can be employed, such as stimulation parameters or movements induced. Moreover, although the short-term physiological and psychological responses during different types of FES exercises have been extensively reported, there are fewer data regarding the long-term effects of FES. Therefore, the purpose of this brief review is to provide a critical appraisal and synthesis of the literature on the use of FES for exercise in paraplegic individuals. After a short introduction underlying the importance of exercise for SCI patients, the main applications and effects of FES are reviewed and discussed. Major findings reveal an increased physiological demand during FES hybrid exercises as compared with arms only exercises. In addition, when repeated within a training period, FES exercises showed beneficial effects on muscle characteristics, force output, exercise capacity, bone mineral density and cardiovascular parameters. In conclusion, there appears to be promising evidence of beneficial effects of FES training, and particularly FES hybrid training, for paraplegic individuals.

Cardiovascular and Affective Outcomes of Active Gaming: Using the Nintendo Wii as a Cardiovascular Training Tool

PubMed Central

Naugle, Keith E.; Naugle, Kelly M.; Wikstrom, Erik A.

2014-01-01

Naugle, KE, Naugle, KM, and Wikstrom, EA. Cardiovascular and affective outcomes of active gaming: Using the Nintendo Wii as a cardiovascular training tool. J Strength Cond Res 28(2): 443–451, 2014–Active-video gaming is purported to produce similar cardiovascular responses as aerobic fitness activities. This study compared the emotional and cardiovascular effects of Wii games with those of traditional exercise in college-aged adults with different exercise backgrounds. Specifically, the percentage of heart rate reserve, rate of perceived exertion (RPE), level of enjoyment, and Positive and Negative Affect Schedule scores were compared between subjects who reported exercising frequently at high intensities (high-intensity exerciser group: age = 20.18 years [0.87]; Height = 165.23 cm [9.97]; Mass = 62.37 kg [11.61]), N = 11 and those who exercise more often at lower intensities (low-intensity exercisers group: age = 20.72 years [1.19]; Height = 164.39 cm [8.05]; Mass = 68.04 kg [10.71]), N = 11. The subjects completed six 20-minute exercises sessions: treadmill walking, stationary cycling, and Wii's Tennis, Boxing, Cycling, and Step. The low-intensity exerciser group achieved a greater percentage of heart rate reserve (a) during traditional exercise compared with that during Wii boxing, (b) playing Wii boxing compared with that for Wii tennis, and (c) playing Wii boxing compared with that when the high-intensity exercisers group played any Wii games (p < 0.05). The RPE was greater for boxing and cycling compared with that for tennis and step (p < 0.05). Ratings of enjoyment and the increase in positive emotion were greater for boxing and for tennis compared with those for traditional exercises (p < 0.05). Results suggest that Wii boxing shows the greatest potential as a cardiovascular fitness tool among the Wii games, particularly for individuals who typically exercise at lower intensities. PMID:23660574

The impact of exercise intensity on the release of cardiac biomarkers in marathon runners.

PubMed

Legaz-Arrese, Alejandro; George, Keith; Carranza-García, Luis Enrique; Munguía-Izquierdo, Diego; Moros-García, Teresa; Serrano-Ostáriz, Enrique

2011-12-01

We sought to determine the influence of exercise intensity on the release of cardiac troponin I (cTnI) and N-terminal pro-brain natriuretic peptide (NT-proBNP) in amateur marathon runners. Fourteen runners completed three exercise trials of the same duration but at exercise intensities corresponding to: (a) a competitive marathon [mean ± SD: heart rate 159 ± 7 beat min(-1), finish time 202 ± 14 min]; (b) 95% of individual anaerobic threshold [heart rate 144 ± 6 beat min(-1)] and; (c) 85% of individual anaerobic threshold [heart rate 129 ± 5 beat min(-1)]. cTnI and NT-proBNP were assayed from blood samples collected before, 30 min and 3 h post-exercise for each trial. cTnI and NT-proBNP were not different at baseline before each trial. After exercise at 85% of individual anaerobic threshold cTnI was not significantly elevated. Conversely, cTnI was elevated after exercise at 95% of individual anaerobic threshold (0.016 μg L(-1)) and to an even greater extent after exercise at competition intensity (0.054 μg L(-1)). Peak post-exercise values of NT-proBNP were elevated to a similar extent after all exercise trials (P < 0.05). The upper reference limit for cTnI (0.04 μg L(-1)) was exceeded in six subjects at competition intensity. No data for NT-proBNP surpassed its upper reference limit. Peak post-exercise values for cTnI and NT-proBNP were correlated with their respective baseline values. These data suggest exercise intensity influences the release of cTnI, but not NT-proBNP, and that competitive marathon running intensity is required for cTnI to be elevated over its upper reference limit.

Submaximal exercise intensity modulates acute post-exercise heart rate variability.

PubMed

Michael, Scott; Jay, Ollie; Halaki, Mark; Graham, Kenneth; Davis, Glen M

2016-04-01

This study investigated whether short-term heart rate variability (HRV) can be used to differentiate between the immediate recovery periods following three different intensities of preceding exercise. 12 males cycled for 8 min at three intensities: LOW (40-45 %), MOD (75-80 %) and HIGH (90-95 %) of heart rate (HR) reserve. HRV was assessed during exercise and throughout 10-min seated recovery. 1-min HR recovery was reduced following greater exercise intensities when expressed as R-R interval (RRI, ms) (p < 0.001), but not b min(-1) (p = 0.217). During exercise, the natural logarithm of root mean square of successive differences (Ln-RMSSD) was higher during LOW (1.66 ± 0.47 ms) relative to MOD (1.14 ± 0.32 ms) and HIGH (1.30 ± 0.25 ms) (p ≤ 0.037). Similar results were observed for high-frequency spectra (Ln-HF-LOW: 2.9 ± 1.0; MOD: 1.6 ± 0.6; HIGH: 1.6 ± 0.3 ms(2), p < 0.001). By 1-min recovery, higher preceding exercise intensities resulted in lower HRV amongst all three intensities for Ln-RMSSD (LOW: 3.45 ± 0.58; MOD: 2.34 ± 0.81; HIGH: 1.66 ± 0.78 ms, p < 0.001) and Ln-HF (LOW: 6.0 ± 1.0; MOD: 4.3 ± 1.4; HIGH: 2.8 ± 1.4 ms(2), p < 0.001). Similarly, by 1-min recovery 'HR-corrected' HRV (Ln-RMSSD: RRI × 10(3)) was different amongst all three intensities (LOW: 3.64 ± 0.49; MOD: 2.90 ± 0.65; HIGH: 2.40 ± 0.67, p < 0.001). These differences were maintained throughout 10-min recovery (p ≤ 0.027). Preceding exercise intensity has a graded effect on recovery HRV measures reflecting cardiac vagal activity, even after correcting for the underlying HR. The immediate recovery following exercise is a potentially useful period to investigate autonomic activity, as multiple levels of autonomic activity can be clearly differentiated between using HRV. When investigating post-exercise HRV it is critical to account for the relative exercise intensity.

The influence of high intensity exercise and the Val66Met polymorphism on circulating BDNF and locomotor learning.

PubMed

Helm, Erin E; Matt, Kathleen S; Kirschner, Kenneth F; Pohlig, Ryan T; Kohl, Dave; Reisman, Darcy S

2017-10-01

Brain-derived neurotrophic factor (BDNF) has been directly related to exercise-enhanced motor performance in the neurologically injured animal model; however literature concerning the role of BDNF in the enhancement of motor learning in the human population is limited. Previous studies in healthy subjects have examined the relationship between intensity of an acute bout of exercise, increases in peripheral BDNF and motor learning of a simple isometric upper extremity task. The current study examined the role of high intensity exercise on upregulation of peripheral BDNF levels as well as the role of high intensity exercise in mediation of motor learning and retention of a novel locomotor task in neurologically intact adults. In addition, the impact of a single nucleotide polymorphism in the BDNF gene (Val66Met) in moderating the relationship between exercise and motor learning was explored. It was hypothesized that participation in high intensity exercise prior to practicing a novel walking task (split-belt treadmill walking) would elicit increases in peripheral BDNF as well as promote an increased rate and magnitude of within session learning and retention on a second day of exposure to the walking task. Within session learning and retention would be moderated by the presence or absence of Val66Met polymorphism. Fifty-four neurologically intact participants participated in two sessions of split-belt treadmill walking. Step length and limb phase were measured to assess learning of spatial and temporal parameters of walking. Serum BDNF was collected prior to and immediately following either high intensity exercise or 5min of quiet rest. The results demonstrated that high intensity exercise provides limited additional benefit to learning of a novel locomotor pattern in neurologically intact adults, despite increases in circulating BDNF. In addition, presence of a single nucleotide polymorphism on the BDNF gene did not moderate the magnitude of serum BDNF increases with high intensity exercise, nor did it moderate the relationship between high intensity exercise and locomotor learning. Copyright © 2017 Elsevier Inc. All rights reserved.

Nutrition Coupled with High-Load Traditional or Low-Load Blood Flow Restricted Exercise During Human Limb Suspension

NASA Technical Reports Server (NTRS)

Hackney, K. J.; Everett, M.; Ploutz-Snyder, L. L.

2011-01-01

High-load resistance exercise (HRE) and low-load blood flow restricted (BFR) exercise have demonstrated efficacy for attenuating unloading related muscle atrophy and dysfunction. In recreational exercisers, protein consumption immediately before and/or after exercise has been shown to increase the skeletal muscle anabolic response to resistance training. PURPOSE: To compare the skeletal muscle adaptations when chocolate milk intake was coupled with HRE or low-load BFR exercise [3 d/wk] during simulated lower limb weightlessness. METHODS: Eleven subjects were counterbalanced [based on age and gender] to HRE (31 +/- 14 yr, 170 +/- 13 cm, 71 +/- 18 kg, 2M/3W) or low-load BFR exercise (31 +/- 12 yr, 169 +/- 13 cm, 66 +/- 14 kg, 2M/4W) during 30 days of unilateral lower limb suspension (ULLS). Both HRE and BFR completed 3 sets of single leg press and calf raise exercise during ULLS. BFR exercise intensity was 20% of repetition maximum (1RM) with a cuff inflation pressure of 1.3 systolic blood pressure (143 4 mmHg). Cuff pressure was maintained during all 3 sets including rest intervals (90s). HRE intensity was 75% 1RM and was performed without cuff inflation. Immediately (<10 min) before and after exercise 8 fl oz of chocolate milk (150 kcal, 2.5g total fat, 22g total carbohydrate, 8g protein) was consumed to optimize acute exercise responses in favor of muscle anabolism. ULLS analog compliance was assessed from leg skin temperature recordings and plantar accelerometry. Muscle cross-sectional area (CSA) for knee extensor and plantar flexor muscle groups were determined from analysis of magnetic resonance images using ImageJ software. 1RM strength for leg press and calf raise was assessed on the Agaton exercise system. Muscular endurance during leg press and calf raise was evaluated from the maximal number of repetitions performed to volitional fatigue using 40% of pre-ULLS 1RM. RESULTS: Steps detected by plantar acceleometry declined by 98.9% during ULLS relative to an ambulatory control period. Average skin temperature of the unloaded calf declined from 27.4 C to 26.8 C (-2.1%), while there was a slight increase (+1.1%) in skin temperature in the loaded calf (27.6 C to 27.9 C). Collectively, these measures indicate strong subject compliance with the ULLS analog. Unloaded limb work performed during leg press (1514 +/- 334 vs. 576 +/- 103) and calf raise (2886 +/- 508 vs. 1233 +/- 153) exercises sessions was greater in HRE vs. BFR, respectively. Leg press training loads were 44 +/- 7 kg in HRE compared to 11 +/- 1 kg in BFR. Similarly, calf raise training loads were 81 +/- 11 kg in HRE and 16 +/- 1 kg in BFR. Pre to post-ULLS training adaptations in the unloaded leg are shown in the table. CONCLUSION: The preliminary results of this investigation suggest when HRE is optimized for muscle anabolism during unloading muscle size and strength are preserved (or enhanced) at the expense of muscle endurance. In contrast, when BFR exercise is optimized for muscle anabolism during unloading muscle endurance is preserved (or enhanced) at the expense of muscle size and strength

Muscle and intensity based hamstring exercise classification in elite female track and field athletes: implications for exercise selection during rehabilitation

PubMed Central

Tsaklis, Panagiotis; Malliaropoulos, Nikos; Mendiguchia, Jurdan; Korakakis, Vasileios; Tsapralis, Kyriakos; Pyne, Debasish; Malliaras, Peter

2015-01-01

Background Hamstring injuries are common in many sports, including track and field. Strains occur in different parts of the hamstring muscle but very little is known about whether common hamstring loading exercises specifically load different hamstring components. The purpose of this study was to investigate muscle activation of different components of the hamstring muscle during common hamstring loading exercises. Methods Twenty elite female track and field athletes were recruited into this study, which had a single-sample, repeated-measures design. Each athlete performed ten hamstring loading exercises, and an electromyogram (EMG) was recorded from the biceps femoris and semitendinosus components of the hamstring. Hamstring EMG during maximal voluntary isometric contraction (MVIC) was used to normalize the mean data across ten repetitions of each exercise. An electrogoniometer synchronized to the EMG was used to determine whether peak EMG activity occurred during muscle-tendon unit lengthening, shortening, or no change in length. Mean EMG values were compared between the two recording sites for each exercise using the Student’s t-test. Results The lunge, dead lift, and kettle swings were low intensity (<50% MVIC) and all showed higher EMG activity for semitendinosus than for biceps femoris. Bridge was low but approaching medium intensity, and the TRX, hamstring bridge, and hamstring curl were all medium intensity exercises (≥50% or <80% MVIC). The Nordic, fitball, and slide leg exercises were all high intensity exercises. Only the fitball exercise showed higher EMG activity in the biceps femoris compared with the semitendinosus. Only lunge and kettle swings showed peak EMG in the muscle-tendon unit lengthening phase and both these exercises involved faster speed. Conclusion Some exercises selectively activated the lateral and medial distal hamstrings. Low, medium, and high intensity exercises were demonstrated. This information enables the clinician, strength and conditioning coach and physiotherapist to better understand intensity- and muscle-specific activation during hamstring muscle rehabilitation. Therefore, these results may help in designing progressive strengthening and rehabilitation and prevention programs. PMID:26170726

Exercise prescription for patients with multiple sclerosis; potential benefits and practical recommendations.

PubMed

Halabchi, Farzin; Alizadeh, Zahra; Sahraian, Mohammad Ali; Abolhasani, Maryam

2017-09-16

Multiple sclerosis (MS) can result in significant mental and physical symptoms, specially muscle weakness, abnormal walking mechanics, balance problems, spasticity, fatigue, cognitive impairment and depression. Patients with MS frequently decrease physical activity due to the fear from worsening the symptoms and this can result in reconditioning. Physicians now believe that regular exercise training is a potential solution for limiting the reconditioning process and achieving an optimal level of patient activities, functions and many physical and mental symptoms without any concern about triggering the onset or exacerbation of disease symptoms or relapse. Appropriate exercise can cause noteworthy and important improvements in different areas of cardio respiratory fitness (Aerobic fitness), muscle strength, flexibility, balance, fatigue, cognition, quality of life and respiratory function in MS patients. Aerobic exercise training with low to moderate intensity can result in the improvement of aerobic fitness and reduction of fatigue in MS patients affected by mild or moderate disability. MS patients can positively adapt to resistance training which may result in improved fatigue and ambulation. Flexibility exercises such as stretching the muscles may diminish spasticity and prevent future painful contractions. Balance exercises have beneficial effects on fall rates and better balance. Some general guidelines exist for exercise recommendation in the MS population. The individualized exercise program should be designed to address a patient's chief complaint, improve strength, endurance, balance, coordination, fatigue and so on. An exercise staircase model has been proposed for exercise prescription and progression for a broad spectrum of MS patients. Exercise should be considered as a safe and effective means of rehabilitation in MS patients. Existing evidence shows that a supervised and individualized exercise program may improve fitness, functional capacity and quality of life as well as modifiable impairments in MS patients.

Effect of Exercise Intensity on Neurotrophic Factors and Blood-Brain Barrier Permeability Induced by Oxidative-Nitrosative Stress in Male College Students.

PubMed

Roh, Hee-Tae; Cho, Su-Youn; Yoon, Hyung-Gi; So, Wi-Young

2017-06-01

We investigated the effects of aerobic exercise intensity on oxidative-nitrosative stress, neurotrophic factor expression, and blood-brain barrier (BBB) permeability. Fifteen healthy men performed treadmill running under low-intensity (LI), moderate-intensity (MI), and high-intensity (HI) conditions. Blood samples were collected immediately before exercise (IBE), immediately after exercise (IAE), and 60 min after exercise (60MAE) to examine oxidative-nitrosative stress (reactive oxygen species [ROS]; nitric oxide [NO]), neurotrophic factors (brain-derived neurotrophic factor [BDNF]; nerve growth factor [NGF]), and blood-brain barrier (BBB) permeability (S-100β; neuron-specific enolase). ROS concentration significantly increased IAE and following HI (4.9 ± 1.7 mM) compared with that after LI (2.8 ± 1.4 mM) exercise (p < .05). At 60MAE, ROS concentration was higher following HI (2.5 ± 1.2 mM) than after LI (1.5 ± 0.5 mM) and MI (1.4 ± 0.3 mM) conditions (p < .05). Plasma NO IAE increased significantly after MI and HI exercise (p < .05). Serum BDNF, NGF, and S-100b levels were significantly higher IAE following MI and HI exercise (p < .05). BDNF and S-100b were higher IAE following MI (29.6 ± 3.4 ng/mL and 87.1 ± 22.8 ng/L, respectively) and HI (31.4 ± 3.8 ng/mL and 100.6 ± 21.2 ng/L, respectively) than following LI (26.5 ± 3.0 ng/mL and 64.8 ± 19.2 ng/L, respectively) exercise (p < .05). 60MAE, S-100b was higher following HI (71.1 ± 14.5 ng/L) than LI (56.2 ± 14.7 ng/L) exercise (p < .05). NSE levels were not significantly different among all intensity conditions and time points (p > .05). Moderate- and/or high-intensity exercise may induce higher oxidative-nitrosative stress than may low-intensity exercise, which can increase peripheral neurotrophic factor levels by increasing BBB permeability.

Comparison of affective responses during and after low volume high-intensity interval exercise, continuous moderate- and continuous high-intensity exercise in active, untrained, healthy males.

PubMed

Niven, Ailsa; Thow, Jacqueline; Holroyd, Jack; Turner, Anthony P; Phillips, Shaun M

2018-09-01

This study compared affective responses to low volume high-intensity interval exercise (HIIE), moderate-intensity continuous exercise (MICE) and high-intensity continuous exercise (HICE). Twelve untrained males ([Formula: see text] 48.2 ± 6.7 ml·kg -1 ·min -1 ) completed MICE (30 min cycle at 85% of ventilatory threshold (VT)), HICE (cycle at 105% of VT matched with MICE for total work), and HIIE (10 x 6 s cycle sprints with 60 s recovery). Affective valence and perceived activation were measured before exercise, post warm-up, every 20% of exercise time, and 1, 5, 10, and 15 min post-exercise. Affective valence during exercise declined by 1.75 ± 2.42, 1.17 ± 1.99, and 0.42 ± 1.38 units in HICE, HIIE, and MICE, respectively, but was not statistically influenced by trial (P = 0.35), time (P = 0.06), or interaction effect (P = 0.08). Affective valence during HICE and HIIE was consistently less positive than MICE. Affective valence post-exercise was not statistically influenced by trial (P = 0.10) and at 5 min post-exercise exceeded end-exercise values (P = 0.048). Circumplex profiles showed no negative affect in any trial. Affective responses to low volume HIIE are similar to HICE but remain positive and rebound rapidly, suggesting it may be a potential alternative exercise prescription.

Effect of exercise intensity on post-exercise oxygen consumption and heart rate recovery.

PubMed

Mann, Theresa N; Webster, Christopher; Lamberts, Robert P; Lambert, Michael I

2014-09-01

There is some evidence that measures of acute post-exercise recovery are sensitive to the homeostatic stress of the preceding exercise and these measurements warrant further investigation as possible markers of training load. The current study investigated which of four different measures of metabolic and autonomic recovery was most sensitive to changes in exercise intensity. Thirty-eight moderately trained runners completed 20-min bouts of treadmill exercise at 60, 70 and 80% of maximal oxygen uptake (VO2max) and four different recovery measurements were determined: the magnitude of excess post-exercise oxygen consumption (EPOCMAG), the time constant of the oxygen consumption recovery curve (EPOCτ), heart rate recovery within 1 min (HRR60s) and the time constant of the heart rate recovery curve (HRRτ) . Despite significant differences in exercise parameters at each exercise intensity, only EPOCMAG showed significantly slower recovery with each increase in exercise intensity at the group level and in the majority of individuals. EPOCτ was significantly slower at 70 and 80% of VO₂max vs. 60% VO₂max and HRRτ was only significantly slower when comparing the 80 vs. 60% VO₂max exercise bouts. In contrast, HRR60s reflected faster recovery at 70 and 80% of VO₂max than at 60% VO₂max. Of the four recovery measurements investigated, EPOCMAG was the most sensitive to changes in exercise intensity and shows potential to reflect changes in the homeostatic stress of exercise at the group and individual level. Determining EPOCMAG may help to interpret the homeostatic stress of laboratory-based research trials or training sessions.

Serratus anterior and lower trapezius muscle activities during multi-joint isotonic scapular exercises and isometric contractions.

PubMed

Tsuruike, Masaaki; Ellenbecker, Todd S

2015-02-01

Proper scapular function during humeral elevation, such as upward rotation, external rotation, and posterior tilting of the scapula, is necessary to prevent shoulder injury. However, the appropriate intensity of rehabilitation exercise for the periscapular muscles has yet to be clarified. To identify the serratus anterior, lower trapezius, infraspinatus, and posterior deltoid muscle activities during 2 free-motion exercises using 3 intensities and to compare these muscle activities with isometric contractions during quadruped shoulder flexion and external rotation and abduction of the glenohumeral joint. Cross-sectional study. Health Science Laboratory. A total of 16 uninjured, healthy, active, male college students (age = 19.5 ± 1.2 years, height = 173.1 ± 6.5 cm, weight = 68.8 ± 6.6 kg). Mean electromyographic activity normalized by the maximal voluntary isometric contraction was analyzed across 3 intensities and 5 exercises. Intraclass correlation coefficients were calculated for electromyographic activity of the 4 muscles in each free-motion exercise. Significant interactions in electromyographic activity were observed between intensities and exercises (P < .05). The quadruped shoulder-flexion exercise activated all 4 muscles compared with other exercises. Also, the modified robbery free-motion exercise activated the serratus anterior, lower trapezius, and infraspinatus compared with the lawn-mower free-motion exercise. However, neither exercise showed a difference in posterior deltoid electromyographic activity. Three intensities exposed the nature of the periscapular muscle activities across the different exercises. The free-motion exercise in periscapular muscle rehabilitation may not modify serratus anterior, lower trapezius, and infraspinatus muscle activities unless knee-joint extension is limited.

A Probability Model of Decompression Sickness at 4.3 Psia after Exercise Prebreathe

NASA Technical Reports Server (NTRS)

Conkin, Johnny; Gernhardt, Michael L.; Powell, Michael R.; Pollock, Neal

2004-01-01

Exercise PB can reduce the risk of decompression sickness on ascent to 4.3 psia when performed at the proper intensity and duration. Data are from seven tests. PB times ranged from 90 to 150 min. High intensity, short duration dual-cycle ergometry was done during the PB. This was done alone, or combined with intermittent low intensity exercise or periods of rest for the remaining PB. Nonambulating men and women performed light exercise from a semi-recumbent position at 4.3 psia for four hrs. The Research Model with age tested the probability that DCS increases with advancing age. The NASA Model with gender hypothesized that the probability of DCS increases if gender is female. Accounting for exercise and rest during PB with a variable half-time compartment for computed tissue N2 pressure advances our probability modeling of hypobaric DCS. Both models show that a small increase in exercise intensity during PB reduces the risk of DCS, and a larger increase in exercise intensity dramatically reduces risk. These models support the hypothesis that aerobic fitness is an important consideration for the risk of hypobaric DCS when exercise is performed during the PB.

Muscle performance following an acute bout of plyometric training combined with low or high intensity weight exercise.

PubMed

Beneka, Anastasia G; Malliou, Paraskevi K; Missailidou, Victoria; Chatzinikolaou, Athanasios; Fatouros, Ioannis; Gourgoulis, Vassilios; Georgiadis, Elias

2013-01-01

To determine the time course of performance responses after an acute bout of plyometric exercise combined with high and low intensity weight training, a 3-group (including a control group), repeated-measures design was employed. Changes in performance were monitored through jumping ability by measuring countermovement and squat jumping, and strength performance assessment through isometric and isokinetic testing of knee extensors (at two different velocities). Participants in both experimental groups performed a plyometric protocol consisting of 50 jumps over 50 cm hurdles and 50 drop jumps from a 50 cm plyometric box. Additionally, each group performed two basic weight exercises consisting of leg presses and leg extensions at 90-95% of maximum muscle strength for the high intensity group and 60% of maximum muscle strength for the low intensity group. The results of the study suggest that an acute bout of intense plyometric exercise combined with weight exercise induces time-dependent changes in performance, which are also dependent on the nature of exercise protocol and testing procedures. In conclusion, acute plyometric exercise with weight exercise may induce a substantial decline in jumping performance for as long as 72 hours but not in other forms of muscle strength.

Closed-Loop Task Difficulty Adaptation during Virtual Reality Reach-to-Grasp Training Assisted with an Exoskeleton for Stroke Rehabilitation

PubMed Central

Grimm, Florian; Naros, Georgios; Gharabaghi, Alireza

2016-01-01

Stroke patients with severe motor deficits of the upper extremity may practice rehabilitation exercises with the assistance of a multi-joint exoskeleton. Although this technology enables intensive task-oriented training, it may also lead to slacking when the assistance is too supportive. Preserving the engagement of the patients while providing “assistance-as-needed” during the exercises, therefore remains an ongoing challenge. We applied a commercially available seven degree-of-freedom arm exoskeleton to provide passive gravity compensation during task-oriented training in a virtual environment. During this 4-week pilot study, five severely affected chronic stroke patients performed reach-to-grasp exercises resembling activities of daily living. The subjects received virtual reality feedback from their three-dimensional movements. The level of difficulty for the exercise was adjusted by a performance-dependent real-time adaptation algorithm. The goal of this algorithm was the automated improvement of the range of motion. In the course of 20 training and feedback sessions, this unsupervised adaptive training concept led to a progressive increase of the virtual training space (p < 0.001) in accordance with the subjects' abilities. This learning curve was paralleled by a concurrent improvement of real world kinematic parameters, i.e., range of motion (p = 0.008), accuracy of movement (p = 0.01), and movement velocity (p < 0.001). Notably, these kinematic gains were paralleled by motor improvements such as increased elbow movement (p = 0.001), grip force (p < 0.001), and upper extremity Fugl-Meyer-Assessment score from 14.3 ± 5 to 16.9 ± 6.1 (p = 0.026). Combining gravity-compensating assistance with adaptive closed-loop feedback in virtual reality provides customized rehabilitation environments for severely affected stroke patients. This approach may facilitate motor learning by progressively challenging the subject in accordance with the individual capacity for functional restoration. It might be necessary to apply concurrent restorative interventions to translate these improvements into relevant functional gains of severely motor impaired patients in activities of daily living. PMID:27895550

Closed-Loop Task Difficulty Adaptation during Virtual Reality Reach-to-Grasp Training Assisted with an Exoskeleton for Stroke Rehabilitation.

PubMed

Grimm, Florian; Naros, Georgios; Gharabaghi, Alireza

2016-01-01

Stroke patients with severe motor deficits of the upper extremity may practice rehabilitation exercises with the assistance of a multi-joint exoskeleton. Although this technology enables intensive task-oriented training, it may also lead to slacking when the assistance is too supportive. Preserving the engagement of the patients while providing "assistance-as-needed" during the exercises, therefore remains an ongoing challenge. We applied a commercially available seven degree-of-freedom arm exoskeleton to provide passive gravity compensation during task-oriented training in a virtual environment. During this 4-week pilot study, five severely affected chronic stroke patients performed reach-to-grasp exercises resembling activities of daily living. The subjects received virtual reality feedback from their three-dimensional movements. The level of difficulty for the exercise was adjusted by a performance-dependent real-time adaptation algorithm. The goal of this algorithm was the automated improvement of the range of motion. In the course of 20 training and feedback sessions, this unsupervised adaptive training concept led to a progressive increase of the virtual training space ( p < 0.001) in accordance with the subjects' abilities. This learning curve was paralleled by a concurrent improvement of real world kinematic parameters, i.e., range of motion ( p = 0.008), accuracy of movement ( p = 0.01), and movement velocity ( p < 0.001). Notably, these kinematic gains were paralleled by motor improvements such as increased elbow movement ( p = 0.001), grip force ( p < 0.001), and upper extremity Fugl-Meyer-Assessment score from 14.3 ± 5 to 16.9 ± 6.1 ( p = 0.026). Combining gravity-compensating assistance with adaptive closed-loop feedback in virtual reality provides customized rehabilitation environments for severely affected stroke patients. This approach may facilitate motor learning by progressively challenging the subject in accordance with the individual capacity for functional restoration. It might be necessary to apply concurrent restorative interventions to translate these improvements into relevant functional gains of severely motor impaired patients in activities of daily living.

Effects of Short-Interval and Long-Interval Swimming Protocols on Performance, Aerobic Adaptations, and Technical Parameters: A Training Study.

PubMed

Dalamitros, Athanasios A; Zafeiridis, Andreas S; Toubekis, Argyris G; Tsalis, George A; Pelarigo, Jailton G; Manou, Vasiliki; Kellis, Spiridon

2016-10-01

Dalamitros, AA, Zafeiridis, AS, Toubekis, AG, Tsalis, GA, Pelarigo, JG, Manou, V, and Kellis, S. Effects of short-interval and long-interval swimming protocols on performance, aerobic adaptations, and technical parameters: A training study. J Strength Cond Res 30(10): 2871-2879, 2016-This study compared 2-interval swimming training programs of different work interval durations, matched for total distance and exercise intensity, on swimming performance, aerobic adaptations, and technical parameters. Twenty-four former swimmers were equally divided to short-interval training group (INT50, 12-16 × 50 m with 15 seconds rest), long-interval training group (INT100, 6-8 × 100 m with 30 seconds rest), and a control group (CON). The 2 experimental groups followed the specified swimming training program for 8 weeks. Before and after training, swimming performance, technical parameters, and indices of aerobic adaptations were assessed. ΙΝΤ50 and ΙΝΤ100 improved swimming performance in 100 and 400-m tests and the maximal aerobic speed (p ≤ 0.05); the performance in the 50-m swim did not change. Posttraining V[Combining Dot Above]O2max values were higher compared with pretraining values in both training groups (p ≤ 0.05), whereas peak aerobic power output increased only in INT100 (p ≤ 0.05). The 1-minute heart rate and blood lactate recovery values decreased after training in both groups (p < 0.01). Stroke length increased in 100 and 400-m swimming tests after training in both groups (p ≤ 0.05); no changes were observed in stroke rate after training. Comparisons between groups on posttraining mean values, after adjusting for pretraining values, revealed no significant differences between ΙΝΤ50 and ΙΝΤ100 for all variables; however, all measures were improved vs. the respective values in the CON (p < 0.001-0.05). In conclusion, when matched for distance and exercise intensity, the short-interval (50 m) and long-interval (100 m) protocols confer analogous improvements in swimming performance, in stroke cycle parameters, and in indices of aerobic adaptations after 8 weeks of training.

Moderate intensity exercise as an adjunct to standard smoking cessation treatment for women: a pilot study.

PubMed

Williams, David M; Whiteley, Jessica A; Dunsiger, Shira; Jennings, Ernestine G; Albrecht, Anna E; Ussher, Michael H; Ciccolo, Joseph T; Parisi, Alfred F; Marcus, Bess H

2010-06-01

Previous randomized controlled trials have not supported moderate intensity exercise as an efficacious adjunct to smoking cessation treatments for women; however, compliance with exercise programs in these studies has been poor. The purpose of this pilot study was to estimate the effects of moderate intensity exercise on smoking cessation outcomes under optimal conditions for exercise program compliance. Sixty previously sedentary, healthy, female smokers were randomized to an 8-week program consisting of brief baseline smoking cessation counseling and the nicotine patch plus either 150 min/week of moderate intensity exercise or contact control. Participants attended a median of 86.4% and 95.5% of prescribed exercise/control sessions, respectively. There was a moderate, though statistically nonsignificant, effect of exercise at post-treatment for objectively verified 7-day point prevalence abstinence (48.3% vs. 23.3%; OR = 3.07, 95% CI: 0.89-11.07) and prolonged abstinence (34.5% vs. 20.0%; OR = 2.11, 95% CI: 0.56-8.32). Effects were attenuated when controlling for potential confounders, and after a 1-month, no-treatment period. The findings provide a preliminary indication that, given adequate compliance, moderate intensity exercise may enhance short-term smoking cessation outcomes for women; however, a larger trial is warranted. (PsycINFO Database Record (c) 2010 APA, all rights reserved).

Vascular adaptive responses to physical exercise and to stress are affected differently by nandrolone administration.

PubMed

Bruder-Nascimento, T; Cordellini, S

2011-04-01

Androgenic anabolic steroid, physical exercise and stress induce cardiovascular adaptations including increased endothelial function. The present study investigated the effects of these conditions alone and in combination on the vascular responses of male Wistar rats. Exercise was started at 8 weeks of life (60-min swimming sessions 5 days per week for 8 weeks, while carrying a 5% body-weight load). One group received nandrolone (5 mg/kg, twice per week for 8 weeks, im). Acute immobilization stress (2 h) was induced immediately before the experimental protocol. Curves for noradrenaline were obtained for thoracic aorta, with and without endothelium from sedentary and trained rats, submitted or not to stress, treated or not with nandrolone. None of the procedures altered the vascular reactivity to noradrenaline in denuded aorta. In intact aorta, stress and exercise produced vascular adaptive responses characterized by endothelium-dependent hyporeactivity to noradrenaline. These conditions in combination did not potentiate the vascular adaptive response. Exercise-induced vascular adaptive response was abolished by nandrolone. In contrast, the aortal reactivity to noradrenaline of sedentary rats and the vascular adaptive response to stress of sedentary and trained rats were not affected by nandrolone. Maximum response for 7-10 rats/group (g): sedentary 3.8 ± 0.2 vs trained 3.0 ± 0.2*; sedentary/stress 2.7 ± 0.2 vs trained/stress 3.1 ± 0.1*; sedentary/nandrolone 3.6 ± 0.1 vs trained/nandrolone 3.8 ± 0.1; sedentary/stress/nandrolone 3.2 ± 0.1 vs trained/stress/nandrolone 2.5 ± 0.1*; *P < 0.05 compared to its respective control. Stress and physical exercise determine similar vascular adaptive response involving distinct mechanisms as indicated by the observation that only the physical exercise-induced adaptive response was abolished by nandrolone.

Skeletal muscle fatigue precedes the slow component of oxygen uptake kinetics during exercise in humans.

PubMed

Cannon, Daniel T; White, Ailish C; Andriano, Melina F; Kolkhorst, Fred W; Rossiter, Harry B

2011-02-01

The mechanisms determining exercise intolerance are poorly understood. A reduction in work efficiency in the form of an additional energy cost and oxygen requirement occurs during high-intensity exercise and contributes to exercise limitation. Muscle fatigue and subsequent recruitment of poorly efficient muscle fibres has been proposed to mediate this decline. These data demonstrate in humans, that muscle fatigue, generated in the initial minutes of exercise, is correlated with the increasing energy demands of high-intensity exercise. Surprisingly, however, while muscle fatigue reached a plateau, oxygen uptake continued to increase throughout 8 min of exercise. This suggests that additional recruitment of inefficient muscle fibres may not be the sole mechanism contributing to the decline in work efficiency during high-intensity exercise.

Virtual and live social facilitation while exergaming: competitiveness moderates exercise intensity.

PubMed

Snyder, Amanda L; Anderson-Hanley, Cay; Arciero, Paul J

2012-04-01

Grounded in social facilitation theory, this study compared the impact on exercise intensity of a virtual versus a live competitor, when riding a virtual reality-enhanced stationary bike ("cybercycle"). It was hypothesized that competitiveness would moderate effects. Twenty-three female college students were exposed to three conditions on a cybercycle: solo training, virtual competitor, and live competitor. After training without a competitor (solo condition for familiarization with equipment), participants competed against a virtual avatar or live rider (random order of presentation). A repeated-measures analysis revealed a significant condition (virtual/live) by competitiveness (high/low) interaction for exercise intensity (watts). More competitive participants exhibited significantly greater exercise intensity when competing against a live versus virtual competitor. The implication is that live competitors can have an added social facilitation effect and influence exercise intensity, although competitiveness moderates this effect.

Effects of exercise training alone vs a combined exercise and nutritional lifestyle intervention on glucose homeostasis in prediabetic individuals: a randomised controlled trial.

PubMed

Slentz, Cris A; Bateman, Lori A; Willis, Leslie H; Granville, Esther O; Piner, Lucy W; Samsa, Gregory P; Setji, Tracy L; Muehlbauer, Michael J; Huffman, Kim M; Bales, Connie W; Kraus, William E

2016-10-01

Although the Diabetes Prevention Program (DPP) established lifestyle changes (diet, exercise and weight loss) as the 'gold standard' preventive therapy for diabetes, the relative contribution of exercise alone to the overall utility of the combined diet and exercise effect of DPP is unknown; furthermore, the optimal intensity of exercise for preventing progression to diabetes remains very controversial. To establish clinical efficacy, we undertook a study (2009 to 2013) to determine: how much of the effect on measures of glucose homeostasis of a 6 month programme modelled after the first 6 months of the DPP is due to exercise alone; whether moderate- or vigorous-intensity exercise is better for improving glucose homeostasis; and to what extent amount of exercise is a contributor to improving glucose control. The primary outcome was improvement in fasting plasma glucose, with improvement in plasma glucose AUC response to an OGTT as the major secondary outcome. The trial was a parallel clinical trial. Sedentary, non-smokers who were 45-75 year old adults (n = 237) with elevated fasting glucose (5.28-6.94 mmol/l) but without cardiovascular disease, uncontrolled hypertension, or diabetes, from the Durham area, were studied at Duke University. They were randomised into one of four 6 month interventions: (1) low amount (42 kJ kg body weight(-1) week(-1) [KKW])/moderate intensity: equivalent of expending 42 KKW (e.g. walking ∼16 km [8.6 miles] per week) with moderate-intensity (50% [Formula: see text]) exercise; (2) high amount (67 KKW)/moderate intensity: equivalent of expending 67 KKW (∼22.3 km [13.8 miles] per week) with moderate-intensity exercise; (3) high amount (67 KKW)/vigorous intensity: equivalent to group 2, but with vigorous-intensity exercise (75% [Formula: see text]); and (4) diet + 42 KKW moderate intensity: same as group 1 but with diet and weight loss (7%) to mimic the first 6 months of the DPP. Computer-generated randomisation lists were provided by our statistician (G. P. Samsa). The randomisation list was maintained by L. H. Willis and C. A. Slentz with no knowledge of or input into the scheduling, whereas all scheduling was done by L. A. Bateman, with no knowledge of the randomisation list. Subjects were automatically assigned to the next group listed on the randomisation sheet (with no ability to manipulate the list order) on the day that they came in for the OGTT, by L. H. Willis. All plasma analysis was done blinded by the individuals doing the measurements (i.e. lipids, glucose, insulin). Subjects and research staff (other than individuals analysing the blood) were not blinded to the group assignments. Number randomised, completers and number analysed with complete OGTT data for each group were: low-amount/moderate-intensity (61, 43, 35); high-amount/moderate-intensity (61, 44, 40); high-amount/vigorous-intensity (61, 43, 38); diet/exercise (54, 45, 37), respectively. Only the diet and exercise group experienced a decrease in fasting glucose (p < 0.001). The means and 95% CIs for changes in fasting glucose (mmol/l) for each group were: high-amount/moderate-intensity -0.07 (-0.20, 0.06); high-amount/vigorous 0.06 (-0.07, 0.19); low-amount/moderate 0.05 (-0.05, 0.15); and diet/exercise -0.32 (-0.46, -0.18). The effects sizes for each group (in the same order) were: 0.17, 0.15, 0.18 and 0.71, respecively. For glucose tolerance (glucose AUC of OGTT), similar improvements were observed for the diet and exercise (8.2% improvement, effect size 0.73) and the 67 KKW moderate-intensity exercise (6.4% improvement, effect size 0.60) groups; moderate-intensity exercise was significantly more effective than the same amount of vigorous-intensity exercise (p < 0.0207). The equivalent amount of vigorous-intensity exercise alone did not significantly improve glucose tolerance (1.2% improvement, effect size 0.21). Changes in insulin AUC, fasting plasma glucose and insulin did not differ among the exercise groups and were numerically inferior to the diet and exercise group. In the present clinical efficacy trial we found that a high amount of moderate-intensity exercise alone was very effective at improving oral glucose tolerance despite a relatively modest 2 kg change in body fat mass. These data, combined with numerous published observations of the strong independent relation between postprandial glucose concentrations and prediction of future diabetes, suggest that walking ∼18.2 km (22.3 km prescribed with 81.6% adherence in the 67 KKW moderate-intensity group) per week may be nearly as effective as a more intensive multicomponent approach involving diet, exercise and weight loss for preventing the progression to diabetes in prediabetic individuals. These findings have important implications for the choice of clinical intervention to prevent progression to type 2 diabetes for those at high risk. ClinicalTrials.gov NCT00962962 FUNDING: The study was funded by National Institutes for Health National Institute of Diabetes and Digestive and Kidney Diseases (NIH-NDDK) (R01DK081559).

Melatonin Supplementation Ameliorates Energy Charge and Oxidative Stress Induced by Acute Exercise in Rat Heart Tissue

PubMed Central

Cimen, Behzat; Uz, Ali; Cetin, Ihsan; Cimen, Leyla; Cetin, Aysun

2017-01-01

Background Regular physical exercises may help people to be more resistant to everyday problems; however, how acute and intense exercises affect the heart tissues functioning with maximum capacity and how melatonin changes the effect of acute and intense exercises are still not obvious. We aimed to comprehend whether melatonin intravenous injection supports the oxidative/antioxidative conditions and energy charge in heart tissues of rats exposed to acute swimming exercise. Methods Thirty Wistar-albino male rats were categorized into 3 groups with equal number of subjects. Control group performed no application, and acute intensive swimming exercise group were subjected to acute intensive swimming exercise for 30 minutes, and melatonin group were applied 25 mg/kg single dose melatonin administration prior to 30 minutes acute intensive swimming exercise. The levels of malondialdehyde (MDA), and superoxide dismutase, catalase and glutathione peroxidase activities were measured by spectrophotometric method; and the levels of 3-nitrotyrosine (3-NT) and energy charge were determined by a high performance liquid chromatography. Results Tissue MDA and 3-NT levels of the acute intensive exercise group were found to be higher than the control group. It was also found that the melatonin administration increased the energy charge and antioxidant activities, while decreased tissue MDA and 3-NT levels in heart tissues. Our results provide evidence for melatonin that can exert potent protective effects on oxidative stress and energy charge for heart tissues in acute swimming exercise. Conclusions These findings suggest that the direct beneficial effects of melatonin could be potentially applied on prevention of oxidative stress and energy deficit. PMID:28959107

Exercise detraining: Applicability to microgravity

NASA Technical Reports Server (NTRS)

Coyle, Edward F.

1994-01-01

Physical training exposes the various systems of the body to potent physiologic stimuli. These stimuli induce specific adaptations that enhance an individual's tolerance for the type of exercise encountered in training. The level of adaptation and the magnitude of improvement in exercise tolerance is proportional to the potency of the physical training stimuli. Likewise, our bodies are stimulated by gravity, which promotes adaptations of both the cardiovascular and skeletal muscles. Exposure to microgravity removes normal stimuli to these systems, and the body adapts to these reduced demands. In many respects the cessation of physical training in athletes and the transition from normal gravity to microgravity represent similar paradigms. Inherent to these situations is the concept of the reversibility of the adaptations induced by training or by exposure to normal gravity. The reversibility concept holds that when physical training is stopped (i.e., detraining) or reduced, or a person goes from normal gravity to microgravity, the bodily systems readjust in accordance with the diminished physiologic stimuli. The focus of this chapter is on the time course of loss of the adaptations to endurance training as well as on the possibility that certain adaptations persist, to some extent, when training is stopped. Because endurance exercise training generally improves cardiovascular function and promotes metabolic adaptations within the exercising skeletal musculature, the reversibility of these specific adaptations is considered. These observations have some applicability to the transition from normal to microgravity.

Intense physical exercise potentiates glucose inhibitory effect over food intake of male Wistar rats.

PubMed

Cavalcanti-de-Albuquerque, Joao Paulo; Kincheski, Grasielle Clotildes; Louzada, Ruy Andrade; Galina, Antônio; Pierucci, Anna Paola Trindade Rocha; Carvalho, Denise P

2018-06-12

What is the central question of this study? Physical exercise has emerged as a non-pharmacological treatment for obesity by promoting changes in energy balance. Despite the accumulated knowledge about exercise effects on energy expenditure, the central question of this study is to understand how an acute session of exercise might affect food intake of male Wistar rats. What is the main finding? The main finding of this work is that food intake in male Wistar rats is decreased in the first hour after physical exercise independent of the intensity. Moreover, high-intensity exercise potentiates the anorexic effect of peripheral glucose administration. Obesity has emerged as a critical metabolic disorder in modern society. An adequate lifestyle with good-oriented programs of diet and physical exercise (PE) can prevent or potentially even cure obesity. Additionally, PE might lead to weight loss by increasing energy expenditure and decreasing hunger perception. In this manuscript, we hypothesize that an acute exercise session with different intensities would potentiate the glucose inhibitory effects on food intake in male Wistar rats. Our data show that moderate- (MOD) or high-intensity (HIGH) PE significantly decreased food intake, although no changes in the expression of feeding-related neuropeptide in the arcuate nucleus of the hypothalamus were found. Exercised animals demonstrated a reduced glucose tolerance and increased blood insulin concentration. Intraperitoneal administration of glucose decreased food intake in control animals. In the animals submitted to MOD, the decrease in food intake promoted by glucose was similar to controls; however, an interaction was observed when glucose was injected in the HIGH group, in which food intake was significantly lower than the effect produced by glucose alone. A different pattern of expression was observed for the monocarboxylate transporter isoforms (MCT1, 2 and 4) and the 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (PFKBP3) in the hypothalamus, which was dependent on the exercise intensity. In conclusion, PE decreases food intake independently of the intensity. However, an interaction between PE and the anorexic effect of glucose is only observed when a high-intensity exercise is performed. These data show an essential role of exercise intensity in the modulation of glucose inhibitory effect on food intake. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Physiological Responses in Relation to Performance during Competition in Elite Synchronized Swimmers

PubMed Central

Rodríguez-Zamora, Lara; Iglesias, Xavier; Barrero, Anna; Chaverri, Diego; Erola, Pau; Rodríguez, Ferran A.

2012-01-01

Purpose We aimed to characterize the cardiovascular, lactate and perceived exertion responses in relation to performance during competition in junior and senior elite synchronized swimmers. Methods 34 high level senior (21.4±3.6 years) and junior (15.9±1.0) synchronized swimmers were monitored while performing a total of 96 routines during an official national championship in the technical and free solo, duet and team competitive programs. Heart rate was continuously monitored. Peak blood lactate was obtained from serial capillary samples during recovery. Post-exercise rate of perceived exertion was assessed using the Borg CR-10 scale. Total competition scores were obtained from official records. Results Data collection was complete in 54 cases. Pre-exercise mean heart rate (beats·min−1) was 129.1±13.1, and quickly increased during the exercise to attain mean peak values of 191.7±8.7, with interspersed bradycardic events down to 88.8±28.5. Mean peak blood lactate (mmol·L−1) was highest in the free solo (8.5±1.8) and free duet (7.6±1.8) and lowest at the free team (6.2±1.9). Mean RPE (0–10+) was higher in juniors (7.8±0.9) than in seniors (7.1±1.4). Multivariate analysis revealed that heart rate before and minimum heart rate during the routine predicted 26% of variability in final total score. Conclusions Cardiovascular responses during competition are characterized by intense anticipatory pre-activation and rapidly developing tachycardia up to maximal levels with interspersed periods of marked bradycardia during the exercise bouts performed in apnea. Moderate blood lactate accumulation suggests an adaptive metabolic response as a result of the specific training adaptations attributed to influence of the diving response in synchronized swimmers. Competitive routines are perceived as very to extremely intense, particularly in the free solo and duets. The magnitude of anticipatory heart rate activation and bradycardic response appear to be related to performance variability. PMID:23155452

Subjective Measures of Exercise Intensity to Gauge Substrate Partitioning in Persons With Paraplegia

PubMed Central

Kressler, Jochen; Cowan, Rachel E.; Ginnity, Kelly; Nash, Mark S.

2012-01-01

Background: The Borg Rating of Perceived Exertion (RPE) Scale and talk test (TT) are commonly recommended for persons to gauge exercise intensity. It is not known whether they are suitable to estimate substrate partitioning between carbohydrate and fat in persons with SCI. Objective: Investigate substrate partitioning/utilization patterns associated with RPE and TT. Methods: Twelve participants with chronic paraplegia underwent 2 arm crank exercise tests on nonconsecutive days within 2 weeks. Test 1 was a graded exercise test (GXT) to volitional exhaustion. Test 2 was a 15-minute self-selected steady state (SS) voluntary arm exercise bout simulating a brief, yet typical exercise session. Results: For the GXT, very light intensity exercise (RPE < 9) and TT stage before last positive were associated with highest contribution of fat oxidation (~35%-50%) to total energy expenditure (TEE). Fat oxidation was low at all stages, with the highest rate (0.13 ± 0.07 g/min) occurring at stage 1 (10 W). Corresponding average RPE was 7 ± 2 and the TT was positive for all participants at this stage. For the SS, fuel partitioning throughout exercise was dominated by carbohydrate oxidation (1.47 ± 0.08 g/min), accounting for almost all (~94%) of TEE with only a minute contribution from fat oxidation (0.02 ± 0.004 g/min). A positive TT was associated with an average contribution of fat oxidation of ~10%. Conclusions: RPE but not the TT appears suitable to predict exercise intensities associated with the highest levels of fat oxidation. However, such intensities are below authoritative intensity thresholds for cardiorespiratory fitness promotion, and therefore the applicability of such a prediction for exercise prescriptions is likely limited to individuals with low exercise tolerance. PMID:23459243

Effect of high-intensity interval exercise on lipid oxidation during postexercise recovery.

PubMed

Malatesta, Davide; Werlen, Catherine; Bulfaro, Stefano; Chenevière, Xavier; Borrani, Fabio

2009-02-01

The aim of this study was to examine whether lipid oxidation predominates during 3 h of postexercise recovery in high-intensity interval exercise as compared with moderate-intensity continuous exercise on a cycle ergometer in fit young men (n = 12; 24.6 +/- 0.6 yr). The energy substrate partitioning was evaluated during and after high-intensity submaximal interval exercise (INT, 1-min intervals at 80% of maximal aerobic power output [Wmax] with an intervening 1 min of active recovery at 40% Wmax) and 60-min moderate-intensity continuous exercise at 45% of maximal oxygen uptake (C45%) as well as a time-matched resting control trial (CON). Exercise bouts were matched for mechanical work output. During exercise, a significantly greater contribution of CHO and a lower contribution of lipid to energy expenditure were found in INT (512.7 +/- 26.6 and 41.0 +/- 14.0 kcal, respectively) than in C45% (406.3 +/- 21.2 and 170.3 +/- 24.0 kcal, respectively; P < 0.001) despite similar overall energy expenditure in both exercise trials (P = 0.13). During recovery, there were no significant differences between INT and C45% in substrate turnover and oxidation (P > 0.05). On the other hand, the mean contribution of lipids to energy yield was significantly higher after exercise trials (C45% = 61.3 +/- 4.2 kcal; INT = 66.7 +/- 4.7 kcal) than after CON (51.5 +/- 3.4 kcal; P < 0.05). These findings show that lipid oxidation during postexercise recovery was increased by a similar amount on two isoenergetic exercise bouts of different forms and intensities compared with the time-matched no-exercise control trial.

Changes in skeletal muscle with aging: effects of exercise training.

PubMed

Rogers, M A; Evans, W J

1993-01-01

There is an approximate 30% decline in muscle strength and a 40% reduction in muscle area between the second and seventh decades of life. Thus, the loss of muscle mass with aging appears to be the major factor in the age-related loss of muscle strength. The loss of muscle mass is partially due to a significant decline in the numbers of both Type I and Type II muscle fibers plus a decrease in the size of the muscle cells, with the Type II fibers showing a preferential atrophy. There appears to be no loss of glycolytic capacity in senescent skeletal muscle whereas muscle oxidative enzyme activity and muscle capillarization decrease by about 25%. Vigorous endurance exercise training in older people, where the stimulus is progressively increased, elicits a proliferation of muscle capillaries, an increase in oxidative enzyme activity, and a significant improvement in VO2max. Likewise, progressive resistive training in older individuals results in muscle hypertrophy and increased strength, if the training stimulus is of a sufficient intensity and duration. Since older individuals adapt to resistive and endurance exercise training in a similar fashion to young people, the decline in the muscle's metabolic and force-producing capacity can no longer be considered as an inevitable consequence of the aging process. Rather, the adaptations in aging skeletal muscle to exercise training may prevent sarcopenia, enhance the ease of carrying out the activities of daily living, and exert a beneficial effect on such age-associated diseases as Type II diabetes, coronary artery disease, hypertension, osteoporosis, and obesity.

Impact of aerobic exercise intensity on craving and reactivity to smoking cues.

PubMed

Janse Van Rensburg, Kate; Elibero, Andrea; Kilpatrick, Marcus; Drobes, David J

2013-06-01

Aerobic exercise can acutely reduce cigarette cravings during periods of nicotine deprivation. The primary aim of this study was to assess the differential effects of light and vigorous intensity aerobic exercise on cigarette cravings, subjective and physiological reactivity to smoking cues, and affect after overnight nicotine deprivation. A secondary aim was to examine cortisol change as a mediator of the effects of exercise on smoking motivation. 162 (55 female, 107 male) overnight nicotine-deprived smokers were randomized to one of three exercise conditions: light intensity, vigorous intensity, or a passive control condition. After each condition, participants engaged in a standardized cue reactivity assessment. Self-reported urges to smoke, affect, and salivary cortisol were assessed at baseline (i.e., before each condition), immediately after each condition, and after the cue reactivity assessment. Light and vigorous exercise significantly decreased urges to smoke and increased positive affect, relative to the control condition. In addition, those in the vigorous exercise condition demonstrated suppressed appetitive reactivity to smoking cues, as indexed by the startle eyeblink reflex. Although exercise intensity was associated with expected changes in cortisol concentration, these effects were not related to changes in craving or cue reactivity. Both light and vigorous exercise can reduce general cravings to smoke, whereas vigorous exercise appears especially well-suited for reducing appetitive reactions to cues that may precede smoking. Results did not support exercise-induced cortisol release as a mechanism for these effects. PsycINFO Database Record (c) 2013 APA, all rights reserved.

Coupling aging immunity with a sedentary lifestyle: has the damage already been done?--a mini-review.

PubMed

Simpson, Richard J; Guy, Keith

2010-01-01

The elderly population is at an unprecedented risk of infectious diseases and malignancy due to apparently inevitable age-related declines in immunity. The 'immune risk profile' (IRP) is an array of biomarkers that has been used to predict morbidity and mortality in older adults. As it is generally accepted that middle-aged and elderly individuals who habitually participate in moderate-intensity exercise are less likely to incur an infection than their sedentary counterparts, this review addresses current knowledge on the effects of regular exercise on aspects of adaptive immunity as they relate to the IRP. Findings from cross-sectional studies mostly show enhanced immunity in physically active compared to sedentary older adults. These include greater T-cell responsiveness to mitogens in vitro, a reduced frequency of antigen-experienced and senescent T-cells (i.e. CD45RO+/KLRG1+/CD57+/CD28-), enhanced IL-2 production and T-lymphocyte expression of the IL-2 receptor, longer chromosome telomere lengths in blood leukocytes and in vivo immune responses to vaccines and recall antigens. In contrast, the evidence from the available longitudinal studies that have used an exercise training intervention in previously sedentary elderly to improve similar immune responses is less compelling. Although this might indicate that exercise has limited immune restorative properties in previously sedentary elderly, there are still relatively few studies that have addressed specific IRP criteria and the large variation in experimental design among the longitudinal studies complicates the juxtaposition of these results. It is clear that a more substantial and focused research approach is required before physical exercise can be used in earnest as an effective immune restorative strategy in the elderly. This mini-review summarizes the major findings of these studies and proposes future avenues of research to investigate the effects of regular exercise on aspects of adaptive immunity in the elderly as they relate to the IRP. Copyright (c) 2009 S. Karger AG, Basel.

Effect of long-term exercise training on blood viscosity during endurance exercise at an anaerobic threshold intensity.

PubMed

Adachi, H; Sakurai, S; Tanehata, M; Oshima, S; Taniguchi, K

2000-11-01

Blood viscosity (etaB) is low in athletes, but the effect of exercise training on etaB during endurance exercise at an anaerobic threshold (AT) intensity in non-athletes is not well known, although it is known that exercise training sometimes induces the hyperviscosity syndrome. Fourteen subjects were recruited and divided into 2 groups: those who trained at an AT intensity for 30 min/day, 3 times weekly for 1 year (Group T, n=8), and sedentary subjects (Group C, n=6). The test protocol consisted of a single 30-min treadmill exercise at each individual's AT intensity, which was determined in advance. The etaB, plasma viscosity (etaP), and hematocrit were measured just before and at the end of the treadmill exercise. The subjects were not allowed to drink any water before exercise. In the Group C subjects, the hematocrit and etaP increased significantly and the etaB tended to increase. However, in the Group T subjects, the hematocrit and etaP did not increase and the etaB decreased significantly. These data indicate that long-term exercise training attenuates the increase in blood viscosity during exercise.

Blood Pressure Response to Exercise and Cardiovascular Disease.

PubMed

Schultz, Martin G; La Gerche, Andre; Sharman, James E

2017-10-18

This review aimed to provide a clinical update on exercise blood pressure (BP) and its relationship to cardiovascular disease (CVD), outlining key determinants of abnormal exercise BP responses. We also highlight current evidence gaps that need addressing in order to optimise the relevance of exercise BP as clinical CVD risk factor. Abnormal exercise BP manifests as either exercise hypotension (low BP response) or as exaggerated exercise BP (high BP response). Exercise hypotension is an established sign of existing and likely severe CVD, but exaggerated exercise BP also carries elevated CVD risk due to its association with sub-clinical hypertension. Although exaggerated exercise BP is related to heightened CVD risk at any exercise intensity, recent data suggest that the BP response to submaximal intensity exercise holds greater prognostic and clinical significance than BP achieved at peak/maximal intensity exercise. Cardiorespiratory fitness is a strong modifier of the exercise BP response, and should be taken into consideration when assessing the association with CVD. Both exercise hypotension and exaggerated exercise BP serve as markers that should prompt evaluation for potential underlying CVD. However, the clinical utility of these markers is currently inhibited by the lack of consensus informing the definitions and thresholds for abnormalities in exercise BP.

Endothelial nitric oxide synthase polymorphisms and adaptation of parasympathetic modulation to exercise training.

PubMed

Silva, Bruno M; Neves, Fabricia J; Negrão, Marcelo V; Alves, Cleber R; Dias, Rodrigo G; Alves, Guilherme B; Pereira, Alexandre C; Rondon, Maria U; Krieger, José E; Negrão, Carlos E; DA Nóbrega, Antonio Claudio Lucas

2011-09-01

There is a large interindividual variation in the parasympathetic adaptation induced by aerobic exercise training, which may be partially attributed to genetic polymorphisms. Therefore, we investigated the association among three polymorphisms in the endothelial nitric oxide gene (-786T>C, 4b4a, and 894G>T), analyzed individually and as haplotypes, and the parasympathetic adaptation induced by exercise training. Eighty healthy males, age 20-35 yr, were genotyped by polymerase chain reaction-restriction fragment length polymorphism analysis, and haplotypes were inferred using the software PHASE 2.1. Autonomic modulation (i.e., HR variability and spontaneous baroreflex sensitivity) and peak oxygen consumption (VO(2peak)) were measured before and after training (running, moderate to severe intensity, three times per week, 60 min·day(-1), during 18 wk). Training increased VO(2peak) (P < 0.05) and decreased mean arterial pressure (P < 0.05) in the whole sample. Subjects with the -786C polymorphic allele had a significant reduction in baroreflex sensitivity after training (change: wild type (-786TT) = 2% ± 89% vs polymorphic (-786TC/CC) = -28% ± 60%, median ± quartile range, P = 0.03), and parasympathetic modulation was marginally reduced in subjects with the 894T polymorphic allele (change: wild type (894GG) = 8% ± 67% vs polymorphic (894GT/TT) = -18% ± 59%, median ± quartile range, P = 0.06). Furthermore, parasympathetic modulation percent change was different between the haplotypes containing wild-type alleles (-786T/4b/894G) and polymorphic alleles at positions -786 and 894 (-786C/4b/894T) (-6% ± 56% vs -41% ± 50%, median ± quartile range, P = 0.04). The polymorphic allele at position -786 and the haplotype containing polymorphic alleles at positions -786 and 894 in the endothelial nitric oxide gene were associated with decreased parasympathetic modulation after exercise training.

High-intensity interval running is perceived to be more enjoyable than moderate-intensity continuous exercise: implications for exercise adherence.

PubMed

Bartlett, Jonathan D; Close, Graeme L; MacLaren, Don P M; Gregson, Warren; Drust, Barry; Morton, James P

2011-03-01

The aim of this study was to objectively quantify ratings of perceived enjoyment using the Physical Activity Enjoyment Scale following high-intensity interval running versus moderate-intensity continuous running. Eight recreationally active men performed two running protocols consisting of high-intensity interval running (6 × 3 min at 90% VO(2max) interspersed with 6 × 3 min active recovery at 50% VO(2max) with a 7-min warm-up and cool down at 70% VO(2max)) or 50 min moderate-intensity continuous running at 70% VO(2max). Ratings of perceived enjoyment after exercise were higher (P < 0.05) following interval running compared with continuous running (88 ± 6 vs. 61 ± 12) despite higher (P < 0.05) ratings of perceived exertion (14 ± 1 vs. 13 ± 1). There was no difference (P < 0.05) in average heart rate (88 ± 3 vs. 87 ± 3% maximum heart rate), average VO(2) (71 ± 6 vs. 73 ± 4%VO(2max)), total VO(2) (162 ± 16 vs. 166 ± 27 L) or energy expenditure (811 ± 83 vs. 832 ± 136 kcal) between protocols. The greater enjoyment associated with high-intensity interval running may be relevant for improving exercise adherence, since running is a low-cost exercise intervention requiring no exercise equipment and similar relative exercise intensities have previously induced health benefits in patient populations.

Practical Approaches to Prescribing Physical Activity and Monitoring Exercise Intensity.

PubMed

Reed, Jennifer L; Pipe, Andrew L

2016-04-01

Regular physical activity helps to prevent heart disease, and reduces the risk of first or subsequent cardiovascular events. It is recommended that Canadian adults accumulate at least 150 minutes of moderate- to vigorous-intensity aerobic exercise per week, in bouts of 10 minutes or more, and perform muscle- and bone-strengthening activities at least 2 days per week. Individual exercise prescriptions can be developed using the frequency, intensity, time, and type principles. Increasing evidence suggests that high-intensity interval training is efficacious for a broad spectrum of heart health outcomes. Several practical approaches to prescribing and monitoring exercise intensity exist including: heart rate monitoring, the Borg rating of perceived exertion scale, the Talk Test, and, motion sensors. The Borg rating of perceived exertion scale matches a numerical value to an individual's perception of effort, and can also be used to estimate heart rate. The Talk Test, the level at which simple conversation is possible, can be used to monitor desired levels of moderate- to vigorous-intensity exercise. Motion sensors can provide users with practical and useful exercise training information to aid in meeting current exercise recommendations. These approaches can be used by the public, exercise scientists, and clinicians to easily and effectively guide physical activity in a variety of settings. Copyright © 2016 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.

Two-dimensional strain echocardiography technology for evaluation of myocardial strain in swimming athletes after high-intensity exercise.

PubMed

Liang, Chen; Ma, Yun; Gao, Can; Zhang, Jianhong; Yang, Min; Chen, Gen; Fu, Shan; Zhu, Tiangang

2017-02-01

The aim of this study was to investigate the change in myocardial strain in swimming athletes before and after high-intensity exercise using two-dimensional strain echocardiography (2DSE) technology. To assess whether the local and overall myocardial function and myocardial injury are accurately measured using 2DSE technology, 15 swimming athletes were selected as research objects. We applied 2DSE technology to track the 2D ultrasound images of the apical four chambers, the apical two chambers, and the apical long axis before and after high-intensity, increasing-load exercise. We recorded indices such as the left ventricular global strain (GS) and the left ventricular segmental wall longitudinal peak systolic strain (PS) in 18 systoles and analyzed the myocardial strain change before and after exercise. After high-intensity exercise, the overall myocardial strain decreased, especially the strain of the posterior wall, posterior divider, lateral wall, lower wall, and the basal and middle segments of the anterior wall. The influence of exercise on myocardial strain was greater on the basal and middle segments than on the apical segment. One-time intensive exercise negatively affected the myocardial muscle. Myocardial muscles in the apical segment and the myocardial wall were more sensitive to intensive exercise. The 2DSE technology can precisely position the motion-sensitive areas and help locate myocardial injury. © 2017, Wiley Periodicals, Inc.

Measuring stroke patients' exercise preferences using a discrete choice experiment.

PubMed

Geidl, Wolfgang; Knocke, Katja; Schupp, Wilfried; Pfeifer, Klaus

2018-03-30

Physical activity post stroke improves health, yet physical inactivity is highly prevalent. Tailored exercise programs considering physical activity preferences are a promising approach to promote physical activity. Therefore, this study seeks to measure exercise preferences of stroke survivors. Stroke survivors conducted a discrete choice experiment (DCE). DCE was presented in a face-to-face interview where patients had to choose eight times between two different exercise programs. Exercise programs differed by characteristics, with the six attributes under consideration being social situation, location, type of exercise, intensity, frequency, and duration. Utilities of the exercise attributes were estimated with a logit choice model. Stroke survivors (n=103, mean age: 67, SD=13.0; 60% male) show significant differences in the rated utilities of the exercise attributes (P<0.001). Participants had strong preferences for light and moderate intense physical activity and favored shorter exercise sessions. Stroke survivors have remarkable exercise preferences especially for intensity and duration of exercise. Results contribute to the tailoring of physical activity programs after stroke thereby facilitating maintenance of physical activity.

No Effect of Exercise Intensity on Appetite in Highly-Trained Endurance Women

PubMed Central

Howe, Stephanie M.; Hand, Taryn M.; Larson-Meyer, D. Enette; Austin, Kathleen J.; Alexander, Brenda M.; Manore, Melinda M.

2016-01-01

In endurance-trained men, an acute bout of exercise is shown to suppress post-exercise appetite, yet limited research has examined this response in women. The purpose of this study was to investigate the effect of exercise intensity on appetite and gut hormone responses in endurance-trained women. Highly-trained women (n = 15, 18–40 years, 58.4 ± 6.4 kg, VO2MAX = 55.2 ± 4.3 mL/kg/min) completed isocaloric bouts (500 kcals or 2093 kJ) of moderate-intensity (MIE, 60% VO2MAX) and high-intensity (HIE, 85% VO2MAX) treadmill running at the same time of day, following a similar 48-h diet/exercise period, and at least 1-week apart. Blood was drawn pre-exercise (baseline), immediately post-exercise and every 20-min for the next 60-min. Plasma concentrations of acylated ghrelin, PYY3–36, GLP-1 and subjective appetite ratings via visual analog scale (VAS) were assessed at each time point. Acylated ghrelin decreased (p = 0.014) and PYY3–36 and GLP-1 increased (p = 0.036, p < 0.0001) immediately post-exercise, indicating appetite suppression. VAS ratings of hunger and desire to eat decreased immediately post-exercise (p = 0.0012, p = 0.0031, respectively), also indicating appetite suppression. There were no differences between exercise intensities for appetite hormones or VAS. Similar to males, post-exercise appetite regulatory hormones were altered toward suppression in highly-trained women and independent of energy cost of exercise. Results are important for female athletes striving to optimize nutrition for endurance performance. PMID:27096869

Comparison of Methods for Determining Aerobic Exercise Intensity Using Heart Rate in Acute Leukemia Patients Prior to Induction Chemotherapy

PubMed Central

Story, Christina; Bryant, Ashley Leak; Phillips, Brett; Bailey, Charlotte; Shields, Edgar W.; Battaglini, Claudio

2018-01-01

Introduction Cardiopulmonary exercise testing (CPET), the gold standard of cardiopulmonary evaluation, is used to determine VO2 levels at different aerobic exercise training intensities; however, it may not be feasible to conduct CPET in all clinical settings. Aims To compare the heart rate reserve (HRR) and percent of 220-age methods for prescribing cycle ergometry exercise intensity using heart rate (HR) against the HRs obtained during a CPET in adults undergoing treatment for acute leukemia (AL). Methods In this exploratory study, part of a larger randomized controlled trial, 14 adults with AL completed CPET on a cycle ergometer with indirect calorimetry within 96 hr of admission to a cancer hospital to determine VO2peak and HR corresponding to low (40% VO2peak), moderate (60% VO2peak), and high (75% VO2peak) exercise intensities. Analyses of variance were used to compare estimated HR for each intensity level using the HRR and percent of 220-age methods with HR determined via VO2peak. Results HR corresponding to low-intensity exercise differed significantly across all three methods (p ≤ .05). No significant differences were observed between HR estimated via the percent of 220-age method and determined via VO2peak at moderate (100 ± 8 and 113 ± 24 bpm, p = .122) or high intensities (125 ± 10 and 123 ± 25 bpm, p = .994). Conclusion In adults with AL, HR-based methods for defining aerobic exercise intensities should be used with caution. At low intensity, neither should be used, while at moderate and high intensities, the percent of 220-age equation might serve as an adequate substitute for CPET. PMID:26933148

Voluntary exercise offers anxiolytic potential and amplifies galanin gene expression in the locus coeruleus of the rat

PubMed Central

Sciolino, Natale R.; Dishman, Rodney K.; Holmes, Philip V.

2012-01-01

Although exercise improves anxiety in humans, it is controversial whether exercise is anxiolytic in rodents. We tested the hypothesis that stress influences the effect of exercise on anxiety-like and defensive behaviors. To explore the neurobiological mechanisms of exercise, we also examined whether exercise alters gene expression for the stress-related peptide galanin. Rats were housed in the presence or absence of a running wheel for 21 d. A subset of these rats were (1) not injected or received a single high, dose of the β-carboline FG7142 (inverse agonist at the benzodiazepine receptor site) immediately prior to testing or (2) were injected repeatedly with vehicle or FG7142 during the last 10 d of exercise. On day 22, anxiety-like and defensive behaviors were measured in the elevated plus maze, shock probe defensive burying, and defensive withdrawal tests. Locus coeruleus prepro-galanin mRNA was measured by in situ hybridization. Exercise and sedentary rats that were not injected exhibited similar behavior in all tests, whereas FG7142 injected immediately prior to the test battery produced intense avoidance and immobility consistent with an anxiety-like response. However, exercise produced anxiolytic-like and active defensive behaviors in the test battery relative to the sedentary condition in rats injected repeatedly with vehicle or FG7142. Exercise also increased prepro-galanin mRNA in the locus coeruleus relative to sedentary controls. These data suggest that the emergence of enhanced adaptive behavior after chronic voluntary exercise is influenced by stress. Our data support a role for galanin in the beneficial consequences of wheel running. PMID:22580167

Exercise and sleep in aging: emphasis on serotonin.

PubMed

Melancon, M O; Lorrain, D; Dionne, I J

2014-10-01

Reductions in central serotonin activity with aging might be involved in sleep-related disorders in later life. Although the beneficial effects of aerobic exercise on sleep are not new, sleep represents a complex recurring state of unconsciousness involving many lines of transmitters which remains only partly clear despite intense ongoing research. It is known that serotonin released into diencephalon and cerebrum might play a key inhibitory role to help promote sleep, likely through an active inhibition of supraspinal neural networks. Several lines of evidence support the stimulatory effects of exercise on higher serotonergic pathways. Hence, exercise has proved to elicit acute elevations in forebrain serotonin concentrations, an effect that waned upon cessation of exercise. While adequate exercise training might lead to adaptations in higher serotonergic networks (desensitization of forebrain receptors), excessive training has been linked to serious brain serotonergic maladaptations accompanied by insomnia. Dietary supplementation of tryptophan (the only serotonin precursor) is known to stimulate serotonergic activity and promote sleep, whereas acute tryptophan depletion causes deleterious effects on sleep. Regarding sleep-wake regulation, exercise has proved to accelerate resynchronization of the biological clock to new light-dark cycles following imposition of phase shifts in laboratory animals. Noteworthy, the effect of increased serotonergic transmission on wake state appears to be biphasic, i.e. promote wake and thereafter drowsiness. Therefore, it might be possible that acute aerobic exercise would act on sleep by increasing activity of ascending brain serotonergic projections, though additional work is warranted to better understand the implication of serotonin in the exercise-sleep axis. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Leisure time physical activity patterns in Odisha, India.

PubMed

Ganesh, G Shankar; Patel, Rishee; Dwivedi, Vikram; Chhabra, Deepak; Balakishore, P; Dakshinamoorthy, Anandhi; Kaur, Parminder

2018-05-01

The World Health Organization has recommended a moderate intensity physical activity of 150min, or 75min vigorous-intensity physical activity per week to achieve optimal health benefits. It is not known if Indian populations who indulge in leisure time physical exercises satisfy these recommendations. This study used a questionnaire to obtain data regarding demographic details, current engagement in leisure time physical activities, and dosages of these exercises from participants between 18 and 64 years of age. Data was collected from a total of 390 participants (231 males and 159 females). 50.76% and 34.35% of the participants reported exercising voluntarily and for health benefits respectively. Most participants (94.61%) indicated exercising without prescription. 55.38% and 12.82% of the participants under and above 38 years of age perform moderate to vigorous intensity exercises respectively. The over-all results of this study indicate that the participants' choices of leisure time physical exercises are based on their personal choices and beliefs. The exercise intensities undertaken do not meet the global recommended intensities, especially in those above 38 years of age. Professionals and facilities to engage the public in the WHO recommended intensities of physical activity needs to be established. Copyright © 2017 Diabetes India. Published by Elsevier Ltd. All rights reserved.

The differential effects of prolonged exercise upon executive function and cerebral oxygenation.

PubMed

Tempest, Gavin D; Davranche, Karen; Brisswalter, Jeanick; Perrey, Stephane; Radel, Rémi

2017-04-01

The acute-exercise effects upon cognitive functions are varied and dependent upon exercise duration and intensity, and the type of cognitive tasks assessed. The hypofrontality hypothesis assumes that prolonged exercise, at physiologically challenging intensities, is detrimental to executive functions due to cerebral perturbations (indicated by reduced prefrontal activity). The present study aimed to test this hypothesis by measuring oxygenation in prefrontal and motor regions using near-infrared spectroscopy during two executive tasks (flanker task and 2-back task) performed while cycling for 60min at a very low intensity and an intensity above the ventilatory threshold. Findings revealed that, compared to very low intensity, physiologically challenging exercise (i) shortened reaction time in the flanker task, (ii) impaired performance in the 2-back task, and (iii) initially increased oxygenation in prefrontal, but not motor regions, which then became stable in both regions over time. Therefore, during prolonged exercise, not only is the intensity of exercise assessed important, but also the nature of the cognitive processes involved in the task. In contrast to the hypofrontality hypothesis, no inverse pattern of oxygenation between prefrontal and motor regions was observed, and prefrontal oxygenation was maintained over time. The present results go against the hypofrontality hypothesis. Copyright © 2017 Elsevier Inc. All rights reserved.

Circulating cell-free DNA: an up-coming molecular marker in exercise physiology.

PubMed

Breitbach, Sarah; Tug, Suzan; Simon, Perikles

2012-07-01

The phenomenon of circulating cell-free DNA (cfDNA) concentrations is of importance for many biomedical disciplines including the field of exercise physiology. Increases of cfDNA due to exercise are described to be a potential hallmark for the overtraining syndrome and might be related to, or trigger adaptations of, immune function induced by strenuous exercise. At the same time, exercise provides a practicable model for studying the phenomenon of cfDNA that is described to be of pathophysiological relevance for different topics in clinical medicine like autoimmune diseases and cancer. In this review, we are summarizing the current knowledge of exercise-based acute and chronic alterations in cfDNA levels and their physiological significance. The effects of acute exercise on cfDNA concentrations have been investigated in resistance exercises and in continuous, stepwise and interval endurance exercises of different durations. cfDNA concentrations peaked immediately after acute exercise and showed a rapid return to baseline levels. Typical markers of skeletal muscle damage (creatine kinase, uric acid, C-reactive protein) show delayed kinetics compared with the cfDNA peak response. Exercise parameters such as intensity, duration or average energy expenditure do not explain the extent of increasing cfDNA concentrations after strenuous exercise. This could be due to complex processes inside the human organism during and after physical activity. Therefore, we hypothesize composite effects of different physiological stress parameters that come along with exercise to be responsible for increasing cfDNA concentrations. We suggest that due to acute stress, cfDNA levels increase rapidly by a spontaneous active or passive release mechanism that is not yet known. As a result of the rapid and parallel increase of cfDNA and lactate in an incremental treadmill test leading to exhaustion within 15-20 minutes, it is unlikely that cfDNA is released into the plasma by typical necrosis or apoptosis of cells in acute exercise settings. Recently, rapid DNA release mechanisms of activated immune-competent cells like NETosis (pathogen-induced cell death including the release of neutrophil extracellular traps [NETs]) have been discovered. cfDNA accumulations might comprise a similar kind of cell death including trap formation or an active release of cfDNA. Just like chronic diseases, chronic high-intensity resistance training protocols induced persistent increases of cfDNA levels. Chronic, strenuous exercise protocols, either long-duration endurance exercise or regular high-intensity workouts, induce chronic inflammation that might lead to a slow, constant release of DNA. This could be due to mechanisms of cell death like apoptosis or necrosis. Yet, it has neither been implicated nor proven sufficiently whether cfDNA can serve as a marker for overtraining. The relevance of cfDNA with regard to overtraining status, performance level, and the degree of physical exhaustion still remains unclear. Longitudinal studies are required that take into account standardized and controlled exercise, serial blood sampling, and large and homogeneous cohorts of different athletic achievement. Furthermore, it is important to establish standardized laboratory procedures for the measurement of genomic cfDNA concentrations by quantitative real-time polymerase chain reaction (PCR). We introduce a new hypothesis based on acute exercise and chronic exposure to stress, and rapid active and passive chronic release of cfDNA fragments into the circulation.

Leisure-time exercise, physical activity during work and commuting, and risk of metabolic syndrome.

PubMed

Kuwahara, Keisuke; Honda, Toru; Nakagawa, Tohru; Yamamoto, Shuichiro; Akter, Shamima; Hayashi, Takeshi; Mizoue, Tetsuya

2016-09-01

Data are limited regarding effect of intensity of leisure-time physical activity on metabolic syndrome. Furthermore, no prospective data are available regarding effect of occupational and commuting physical activity on metabolic syndrome. We compared metabolic syndrome risk by intensity level of leisure-time exercise and by occupational and commuting physical activity in Japanese workers. We followed 22,383 participants, aged 30-64 years, without metabolic syndrome until 2014 March (maximum, 5 years of follow-up). Physical activity was self-reported. Metabolic syndrome was defined by the Joint Statement criteria. We used Cox regression models to estimate the hazard ratios (HRs) and 95 % confidence intervals (CIs) of metabolic syndrome. During a mean follow-up of 4.1 years, 5361 workers developed metabolic syndrome. After adjustment for covariates, compared with engaging in no exercise, the HRs (95 % CIs) for <7.5, 7.5 to <16.5, and ≥16.5 metabolic equivalent hours of exercise per week were 0.99 (0.90, 1.08), 0.99 (0.90, 1.10), and 0.95 (0.83, 1.08), respectively, among individuals engaging in moderate-intensity exercise alone; 0.93 (0.75, 1.14), 0.81 (0.64, 1.02), and 0.84 (0.66, 1.06), among individuals engaging in vigorous-intensity exercise alone; and 0.90 (0.70, 1.17), 0.74 (0.62, 0.89), and 0.81 (0.69, 0.96) among individuals engaging in the two intensities. Higher occupational physical activity was weakly but significantly associated with lower risk of metabolic syndrome. Walking to and from work was not associated with metabolic syndrome. Vigorous-intensity exercise alone or vigorous-intensity combined with moderate-intensity exercise and worksite intervention for physical activity may help prevent metabolic syndrome for Japanese workers.

Effects of exercise amount and intensity on abdominal obesity and glucose tolerance in obese adults: a randomized trial.

PubMed

Ross, Robert; Hudson, Robert; Stotz, Paula J; Lam, Miu

2015-03-03

Exercise reduces obesity and related glucose tolerance, but whether increasing exercise intensity offers additional benefit at fixed exercise amounts is unknown. To determine the separate effects of exercise amount and intensity on abdominal obesity and glucose tolerance. 24-week, single-center, parallel-group trial from 2009 to 2013. (ClinicalTrials.gov: NCT00955071). Kingston, Ontario, Canada. 300 abdominally obese adults. Control (no exercise) (n = 75) or 5 weekly sessions of low-amount, low-intensity exercise (LALI) (180 and 300 kcal/session for women and men, respectively, at 50% of maximum oxygen consumption [V̇o2peak]) (n = 73); high-amount, low-intensity exercise (HALI) (360 and 600 kcal/session, respectively, at 50% of V̇o2peak) (n = 76); or high-amount, high-intensity exercise (HAHI) (360 and 600 kcal/session, respectively, at 75% of V̇o2peak) (n = 76). Daily unsupervised physical activity and sedentary time were measured by accelerometer. Waist circumference and 2-hour glucose level (primary outcomes) and cardiorespiratory fitness and measures of insulin action (secondary measurements). 217 participants (72.3%) completed the intervention. Mean exercise time in minutes per session was 31 (SD, 4.4) for LALI, 58 (SD, 7.6) for HALI, and 40 (SD, 6.2) for HAHI. Daily unsupervised physical activity and sedentary time did not change in any exercise group versus control (P > 0.33). After adjustment for age and sex in a linear mixed model, reductions in waist circumference were greater in the LALI (-3.9 cm [95% CI, -5.6 to -2.3 cm]; P < 0.001), HALI (-4.6 cm [CI, -6.2 to -3.0 cm]; P < 0.001), and HAHI (-4.6 cm [CI, -6.3 to -2.9 cm]; P < 0.001) groups than the control group but did not differ among the exercise groups (P > 0.43). After adjustment for covariates, reductions in 2-hour glucose level were greater in the HAHI group (-0.7 mmol/L [-12.5 mg/dL] [CI, -1.3 to -0.1 mmol/L {-23.5 to -1.5 mg/dL}]; P = 0.027) than the control group but did not differ for the LALI or HALI group versus the control group (P > 0.159). Weight loss was greater in all exercise groups than the control group (P < 0.001); however, reduction in body weight did not differ among the exercise groups (P > 0.182). The clinical importance of reducing 2-hour glucose level in nondiabetic adults remains undetermined. Fixed amounts of exercise independent of exercise intensity resulted in similar reductions in abdominal obesity. Reduction in 2-hour glucose level was restricted to high-intensity exercise.

Canadian Society for Exercise Physiology position paper: resistance training in children and adolescents.

PubMed

Behm, David G; Faigenbaum, Avery D; Falk, Baraket; Klentrou, Panagiota

2008-06-01

Many position stands and review papers have refuted the myths associated with resistance training (RT) in children and adolescents. With proper training methods, RT for children and adolescents can be relatively safe and improve overall health. The objective of this position paper and review is to highlight research and provide recommendations in aspects of RT that have not been extensively reported in the pediatric literature. In addition to the well-documented increases in muscular strength and endurance, RT has been used to improve function in pediatric patients with cystic fibrosis and cerebral palsy, as well as pediatric burn victims. Increases in children's muscular strength have been attributed primarily to neurological adaptations due to the disproportionately higher increase in muscle strength than in muscle size. Although most studies using anthropometric measures have not shown significant muscle hypertrophy in children, more sensitive measures such as magnetic resonance imaging and ultrasound have suggested hypertrophy may occur. There is no minimum age for RT for children. However, the training and instruction must be appropriate for children and adolescents, involving a proper warm-up, cool-down, and appropriate choice of exercises. It is recommended that low- to moderate-intensity resistance exercise should be done 2-3 times/week on non-consecutive days, with 1-2 sets initially, progressing to 4 sets of 8-15 repetitions for 8-12 exercises. These exercises can include more advanced movements such as Olympic-style lifting, plyometrics, and balance training, which can enhance strength, power, co-ordination, and balance. However, specific guidelines for these more advanced techniques need to be established for youth. In conclusion, an RT program that is within a child's or adolescent's capacity and involves gradual progression under qualified instruction and supervision with appropriately sized equipment can involve more advanced or intense RT exercises, which can lead to functional (i.e., muscular strength, endurance, power, balance, and co-ordination) and health benefits.

The effect of exercise mode and intensity of sub-maximal physical activities on salivary testosterone to cortisol ratio and α-amylase in young active males

PubMed Central

AZARBAYJANI, MOHAMMAD ALI; FATOLAHI, HOSEYN; RASAEE, MOHAMMAD JAVAD; PEERI, MAGHSOD; BABAEI, ROHOLAH

2011-01-01

We examined the effect of exercise intensity and mode on the acute responses of free testosterone to cortisol ratio and salivary α-amylase. We also evaluated the relationship between cortisol and salivary α-amylase. Ten healthy young active males participated voluntarily in this study in six single sessions. They exercised on a cycle ergo meter, treadmill, and elliptical instrument at intensities of 70% and 85% maximum heart rate for 25 minutes. Saliva samples were collected 5 minutes before and 5 minutes after each exercise session. No significant changes were observed for cortisol. Free testosterone to cortisol ratio increased during each exercise session (F5, 45=3.15, P=0.02). However, these changes are only significant after exercise on the treadmill at 70% maximum heart rate (t=2.94, P=0.02) and 85% maximum heart rate (t=0.53, P=0.03). Salivary α-amylase significantly varied among exercise sessions (F5, 45=3.97, P=0.005), and a significant decline was observed after exercise on the elliptical instrument (t=2.38, P=0.04) and treadmill (t=3.55, P=0.006) at 85% maximum heart rate. We found that the free testosterone to cortisol ratio is dependent on the exercise mode, while the salivary α-amylase response is dependent on the intensity of exercise. The increase of free testosterone to cortisol ratio in this study may indicate lower physiological stress in response to performing these exercises. Applying muscular strength with moderate intensity weight-bearing exercises possibly activates the anabolic pathways. Although the cortisol and salivary α-amylase responses were opposite in the majority of the exercise sessions, no significant inverse relationship was observed. PMID:27182369

The effect of exercise mode and intensity of sub-maximal physical activities on salivary testosterone to cortisol ratio and α-amylase in young active males.

PubMed

Azarbayjani, Mohammad Ali; Fatolahi, Hoseyn; Rasaee, Mohammad Javad; Peeri, Maghsod; Babaei, Roholah

We examined the effect of exercise intensity and mode on the acute responses of free testosterone to cortisol ratio and salivary α-amylase. We also evaluated the relationship between cortisol and salivary α-amylase. Ten healthy young active males participated voluntarily in this study in six single sessions. They exercised on a cycle ergo meter, treadmill, and elliptical instrument at intensities of 70% and 85% maximum heart rate for 25 minutes. Saliva samples were collected 5 minutes before and 5 minutes after each exercise session. No significant changes were observed for cortisol. Free testosterone to cortisol ratio increased during each exercise session (F 5, 45 =3.15, P=0.02) . However, these changes are only significant after exercise on the treadmill at 70% maximum heart rate ( t=2.94, P=0.02 ) and 85% maximum heart rate ( t=0.53, P=0.03 ). Salivary α-amylase significantly varied among exercise sessions (F 5, 45 =3.97, P=0.005), and a significant decline was observed after exercise on the elliptical instrument (t=2.38, P=0.04) and treadmill ( t=3.55, P=0.006 ) at 85% maximum heart rate. We found that the free testosterone to cortisol ratio is dependent on the exercise mode, while the salivary α-amylase response is dependent on the intensity of exercise. The increase of free testosterone to cortisol ratio in this study may indicate lower physiological stress in response to performing these exercises. Applying muscular strength with moderate intensity weight-bearing exercises possibly activates the anabolic pathways. Although the cortisol and salivary α-amylase responses were opposite in the majority of the exercise sessions, no significant inverse relationship was observed.

Serratus Anterior and Lower Trapezius Muscle Activities During Multi-Joint Isotonic Scapular Exercises and Isometric Contractions.

PubMed

Tsuruike, Masaaki; Ellenbecker, Todd

2014-11-14

Context :  Proper scapular function during humeral elevation, such as upward rotation, external rotation, and posterior tilting of the scapula, is necessary to prevent shoulder injury. However, the appropriate intensity of rehabilitation exercise for the periscapular muscles has yet to be clarified. Objective :  To identify the serratus anterior, lower trapezius, infraspinatus, and posterior deltoid muscle activities during 2 free-motion exercises using 3 intensities and to compare these muscle activities with isometric contractions during quadruped shoulder flexion and external rotation and abduction of the glenohumeral joint. Design :  Cross-sectional study. Setting :  Health Science Laboratory. Patients or Other Participants :  A total of 16 uninjured, healthy, active, male college students (age = 19.5 ± 1.2 years, height = 173.1 ± 6.5 cm, weight = 68.8 ± 6.6 kg). Main Outcome Measure(s) :  Mean electromyographic activity normalized by the maximal voluntary isometric contraction was analyzed across 3 intensities and 5 exercises. Intraclass correlation coefficients were calculated for electromyographic activity of the 4 muscles in each free-motion exercise. Results :  Significant interactions in electromyographic activity were observed between intensities and exercises (P < .05). The quadruped shoulder-flexion exercise activated all 4 muscles compared with other exercises. Also, the modified robbery free-motion exercise activated the serratus anterior, lower trapezius, and infraspinatus compared with the lawn-mower free-motion exercise. However, neither exercise showed a difference in posterior deltoid electromyographic activity. Conclusions :  Three intensities exposed the nature of the periscapular muscle activities across the different exercises. The free-motion exercise in periscapular muscle rehabilitation may not modify serratus anterior, lower trapezius, and infraspinatus muscle activities unless knee-joint extension is limited.

Serratus Anterior and Lower Trapezius Muscle Activities During Multi-Joint Isotonic Scapular Exercises and Isometric Contractions

PubMed Central

Tsuruike, Masaaki; Ellenbecker, Todd S.

2015-01-01

Context: Proper scapular function during humeral elevation, such as upward rotation, external rotation, and posterior tilting of the scapula, is necessary to prevent shoulder injury. However, the appropriate intensity of rehabilitation exercise for the periscapular muscles has yet to be clarified. Objective: To identify the serratus anterior, lower trapezius, infraspinatus, and posterior deltoid muscle activities during 2 free-motion exercises using 3 intensities and to compare these muscle activities with isometric contractions during quadruped shoulder flexion and external rotation and abduction of the glenohumeral joint. Design: Cross-sectional study. Setting: Health Science Laboratory. Patients or Other Participants: A total of 16 uninjured, healthy, active, male college students (age = 19.5 ± 1.2 years, height = 173.1 ± 6.5 cm, weight = 68.8 ± 6.6 kg). Main Outcome Measure(s): Mean electromyographic activity normalized by the maximal voluntary isometric contraction was analyzed across 3 intensities and 5 exercises. Intraclass correlation coefficients were calculated for electromyographic activity of the 4 muscles in each free-motion exercise. Results: Significant interactions in electromyographic activity were observed between intensities and exercises (P < .05). The quadruped shoulder-flexion exercise activated all 4 muscles compared with other exercises. Also, the modified robbery free-motion exercise activated the serratus anterior, lower trapezius, and infraspinatus compared with the lawn-mower free-motion exercise. However, neither exercise showed a difference in posterior deltoid electromyographic activity. Conclusions: Three intensities exposed the nature of the periscapular muscle activities across the different exercises. The free-motion exercise in periscapular muscle rehabilitation may not modify serratus anterior, lower trapezius, and infraspinatus muscle activities unless knee-joint extension is limited. PMID:25689561

Nutritional support to maintain proper immune status during intense training.

PubMed

Gleeson, Michael

2013-01-01

Prolonged exercise and heavy training are associated with depressed immune function which can increase the risk of picking up minor infections. To maintain robust immunity, athletes should eat a well-balanced diet sufficient to meet their energy, carbohydrate, protein, and micronutrient requirements. Dietary deficiencies of protein and specific micronutrients have long been associated with immune dysfunction and an adequate intake of iron, zinc, and vitamins A, D, E, B6 and B12 is particularly important in the maintenance of immune function. Consuming carbohydrate during prolonged strenuous exercise attenuates rises in stress hormones and appears to limit the degree of exercise-induced immune depression. Similar effects can be seen with daily ingestion of high-dose antioxidant vitamin supplements, though concerns have been expressed that excessive antioxidant intake may impair exercise training adaptations. It is safe to say with reasonable confidence that individual amino acids, colostrum, Echinacea, and zinc are unlikely to boost immunity or reduce infection risk in athletes. The ingestion of carbohydrate during exercise and daily consumption of probiotic and plant polyphenol (e.g. quercetin)-containing supplements or foodstuffs (e.g. non-alcoholic beer) currently offer the best chance of success. This approach is likely to be most effective for individuals who are particularly prone to illness. Copyright © 2013 Nestec Ltd., Vevey/S. Karger AG, Basel.

Molecular Mechanisms Underlying Cardiac Adaptation to Exercise

PubMed Central

Vega, Rick B.; Konhilas, John P.; Kelly, Daniel P.; Leinwand, Leslie A.

2017-01-01

Exercise elicits coordinated multi-organ responses including skeletal muscle, vasculature, heart and lung. In the short term, the output of the heart increases to meet the demand of strenuous exercise. Long term exercise instigates remodeling of the heart including growth and adaptive molecular and cellular re-programming. Signaling pathways such as the insulin-like growth factor 1/PI3K/Akt pathway mediate many of these responses. Exercise-induced, or physiologic, cardiac growth contrasts with growth elicited by pathological stimuli such as hypertension. Comparing the molecular and cellular underpinnings of physiologic and pathologic cardiac growth has unveiled phenotype-specific signaling pathways and transcriptional regulatory programs. Studies suggest that exercise pathways likely antagonize pathological pathways, and exercise training is often recommended for patients with chronic stable heart failure or following myocardial infarction. Herein, we summarize the current understanding of the structural and functional cardiac responses to exercise as well as signaling pathways and downstream effector molecules responsible for these adaptations. PMID:28467921

High-intensity interval training vs. moderate-intensity continuous exercise training in heart failure with preserved ejection fraction: a pilot study.

PubMed

Angadi, Siddhartha S; Mookadam, Farouk; Lee, Chong D; Tucker, Wesley J; Haykowsky, Mark J; Gaesser, Glenn A

2015-09-15

Heart failure with preserved ejection fraction (HFpEF) is a major cause of morbidity and mortality. Exercise training is an established adjuvant therapy in heart failure; however, the effects of high-intensity interval training (HIIT) in HFpEF are unknown. We compared the effects of HIIT vs. moderate-intensity aerobic continuous training (MI-ACT) on peak oxygen uptake (V̇o₂peak), left ventricular diastolic dysfunction, and endothelial function in patients with HFpEF. Nineteen patients with HFpEF (age 70 ± 8.3 yr) were randomized to either HIIT (4 × 4 min at 85-90% peak heart rate, with 3 min active recovery) or MI-ACT (30 min at 70% peak heart rate). Fifteen patients completed exercise training (HIIT: n = 9; MI-ACT: n = 6). Patients trained 3 days/wk for 4 wk. Before and after training patients underwent a treadmill test for V̇o₂peak determination, 2D-echocardiography for assessment of left ventricular diastolic dysfunction, and brachial artery flow-mediated dilation (FMD) for assessment of endothelial function. HIIT improved V̇o₂peak (pre = 19.2 ± 5.2 ml·kg(-1)·min(-1); post = 21.0 ± 5.2 ml·kg(-1)·min(-1); P = 0.04) and left ventricular diastolic dysfunction grade (pre = 2.1 ± 0.3; post = 1.3 ± 0.7; P = 0.02), but FMD was unchanged (pre = 6.9 ± 3.7%; post = 7.0 ± 4.2%). No changes were observed following MI-ACT. A trend for reduced left atrial volume index was observed following HIIT compared with MI-ACT (-3.3 ± 6.6 vs. +5.8 ± 10.7 ml/m(2); P = 0.06). In HFpEF patients 4 wk of HIIT significantly improved V̇o₂peak and left ventricular diastolic dysfunction. HIIT may provide a more robust stimulus than MI-ACT for early exercise training adaptations in HFpEF. Copyright © 2015 the American Physiological Society.

Muscle Activation During Exercise in Severe Acute Hypoxia: Role of Absolute and Relative Intensity

PubMed Central

Torres-Peralta, Rafael; Losa-Reyna, José; González-Izal, Miriam; Perez-Suarez, Ismael; Calle-Herrero, Jaime; Izquierdo, Mikel

2014-01-01

Abstract Torres-Peralta, Rafael, José Losa-Reyna, Miriam González-Izal, Ismael Perez-Suarez, Jaime Calle-Herrero, Mikel Izquierdo, and José A.L. Calbet. Muscle activation during exercise in severe acute hypoxia: Role of absolute and relative intensity. High Alt Med Biol 15:472–482, 2014.—The aim of this study was to determine the influence of severe acute hypoxia on muscle activation during whole body dynamic exercise. Eleven young men performed four incremental cycle ergometer tests to exhaustion breathing normoxic (FIo2=0.21, two tests) or hypoxic gas (FIo2=0.108, two tests). Surface electromyography (EMG) activities of rectus femoris (RF), vastus medialis (VL), vastus lateralis (VL), and biceps femoris (BF) were recorded. The two normoxic and the two hypoxic tests were averaged to reduce EMG variability. Peak Vo2 was 34% lower in hypoxia than in normoxia (p<0.05). The EMG root mean square (RMS) increased with exercise intensity in all muscles (p<0.05), with greater effect in hypoxia than in normoxia in the RF and VM (p<0.05), and a similar trend in VL (p=0.10). At the same relative intensity, the RMS was greater in normoxia than in hypoxia in RF, VL, and BF (p<0.05), with a similar trend in VM (p=0.08). Median frequency increased with exercise intensity (p<0.05), and was higher in hypoxia than in normoxia in VL (p<0.05). Muscle contraction burst duration increased with exercise intensity in VM and VL (p<0.05), without clear effects of FIo2. No significant FIo2 effects on frequency domain indices were observed when compared at the same relative intensity. In conclusion, muscle activation during whole body exercise increases almost linearly with exercise intensity, following a muscle-specific pattern, which is adjusted depending on the FIo2 and the relative intensity of exercise. Both VL and VM are increasingly involved in power output generation with the increase of intensity and the reduction in FIo2. PMID:25225839

Effect of exercise intensity on abdominal fat loss during calorie restriction in overweight and obese postmenopausal women: a randomized, controlled trial1234

PubMed Central

Nicklas, Barbara J; Wang, Xuewen; You, Tongjian; Lyles, Mary F; Demons, Jamehl; Easter, Linda; Berry, Michael J; Lenchik, Leon; Carr, J Jeffrey

2009-01-01

Background: Exercise intensity may affect the selective loss of abdominal adipose tissue. Objective: This study showed whether aerobic exercise intensity affects the loss of abdominal fat and improvement in cardiovascular disease risk factors under conditions of equal energy deficit in women with abdominal obesity. Design: This was a randomized trial in 112 overweight and obese [body mass index (in kg/m2): 25–40; waist circumference >88 cm], postmenopausal women assigned to one of three 20-wk interventions of equal energy deficit: calorie restriction (CR only), CR plus moderate-intensity aerobic exercise (CR + moderate-intensity), or CR plus vigorous-intensity exercise (CR + vigorous-intensity). The diet was a controlled program of underfeeding during which meals were provided at individual calorie levels (≈400 kcal/d). Exercise (3 d/wk) involved treadmill walking at an intensity of 45–50% (moderate-intensity) or 70–75% (vigorous-intensity) of heart rate reserve. The primary outcome was abdominal visceral fat volume. Results: Average weight loss for the 95 women who completed the study was 12.1 kg (±4.5 kg) and was not significantly different across groups. Maximal oxygen uptake (O2max) increased more in the CR + vigorous-intensity group than in either of the other groups (P < 0.05). The CR-only group lost relatively more lean mass than did either exercise group (P < 0.05). All groups showed similar decreases in abdominal visceral fat (≈25%; P < 0.001 for all). However, changes in visceral fat were inversely related to increases in O2max (P < 0.01). Changes in lipids, fasting glucose or insulin, and 2-h glucose and insulin areas during the oral-glucose-tolerance test were similar across treatment groups. Conclusion: With a similar amount of total weight loss, lean mass is preserved, but there is not a preferential loss of abdominal fat when either moderate- or vigorous-intensity aerobic exercise is performed during caloric restriction. This trial was registered at clinicaltrials.gov as NCT00664729. PMID:19211823

The effect of exercise mode on the acute response of satellite cells in old men.

PubMed

Nederveen, J P; Joanisse, S; Séguin, C M L; Bell, K E; Baker, S K; Phillips, S M; Parise, G

2015-12-01

A dysregulation of satellite cells may contribute to the progressive loss of muscle mass that occurs with age; however, older adults retain the ability to activate and expand their satellite cell pool in response to exercise. The modality of exercise capable of inducing the greatest acute response is unknown. We sought to characterize the acute satellite cell response following different modes of exercise in older adults. Sedentary older men (n = 22; 67 ± 4 years; 27 ± 2.6 kg*m(-2) ) were randomly assigned to complete an acute bout of either resistance exercise, high-intensity interval exercise on a cycle ergometer or moderate-intensity aerobic exercise. Muscle biopsies were obtained before, 24 and 48 h following each exercise bout. The satellite cell response was analysed using immunofluorescent microscopy of muscle cross sections. Satellite cell expansion associated with type I fibres was observed 24 and 48 h following resistance exercise only (P ˂ 0.05), while no expansion of type II-associated satellite cells was observed in any group. There was a greater number of activated satellite cells 24 h following resistance exercise (pre: 1.3 ± 0.1, 24 h: 4.8 ± 0.5 Pax7 + /MyoD+cells/100 fibres) and high-intensity interval exercise (pre: 0.7 ± 0.3, 24 h: 3.1 ± 0.3 Pax7 + /MyoD+cells/100 fibres) (P ˂ 0.05). The percentage of type I-associated SC co-expressing MSTN was reduced only in the RE group 24 h following exercise (pre: 87 ± 4, 24 h: 57 ± 5%MSTN+ type I SC) (P < 0.001). Although resistance exercise is the most potent exercise type to induce satellite cell pool expansion, high-intensity interval exercise was also more potent than moderate-intensity aerobic exercise in inducing satellite cell activity. © 2015 Scandinavian Physiological Society. Published by John Wiley & Sons Ltd.

Exercise Training during Normobaric Hypoxic Confinement Does Not Alter Hormonal Appetite Regulation

PubMed Central

Debevec, Tadej; Simpson, Elizabeth J.; Macdonald, Ian A.; Eiken, Ola; Mekjavic, Igor B.

2014-01-01

Background Both exposure to hypoxia and exercise training have the potential to modulate appetite and induce beneficial metabolic adaptations. The purpose of this study was to determine whether daily moderate exercise training performed during a 10-day exposure to normobaric hypoxia alters hormonal appetite regulation and augments metabolic health. Methods Fourteen healthy, male participants underwent a 10-day hypoxic confinement at ∼4000 m simulated altitude (FIO2 = 0.139±0.003%) either combined with daily moderate intensity exercise (Exercise group; N = 8, Age = 25.8±2.4 yrs, BMI = 22.9±1.2 kg·m−2) or without any exercise (Sedentary group; N = 6 Age = 24.8±3.1 yrs, BMI = 22.3±2.5 kg·m−2). A meal tolerance test was performed before (Pre) and after the confinement (Post) to quantify fasting and postprandial concentrations of selected appetite-related hormones and metabolic risk markers. 13C-Glucose was dissolved in the test meal and 13CO2 determined in breath samples. Perceived appetite ratings were obtained throughout the meal tolerance tests. Results While body mass decreased in both groups (−1.4 kg; p = 0.01) following the confinement, whole body fat mass was only reduced in the Exercise group (−1.5 kg; p = 0.01). At Post, postprandial serum insulin was reduced in the Sedentary group (−49%; p = 0.01) and postprandial plasma glucose in the Exercise group (−19%; p = 0.03). Fasting serum total cholesterol levels were reduced (−12%; p = 0.01) at Post in the Exercise group only, secondary to low-density lipoprotein cholesterol reduction (−16%; p = 0.01). No differences between groups or testing periods were noted in fasting and/or postprandial concentrations of total ghrelin, peptide YY, and glucagon-like peptide-1, leptin, adiponectin, expired 13CO2 as well as perceived appetite ratings (p>0.05). Conclusion These findings suggest that performing daily moderate intensity exercise training during continuous hypoxic exposure does not alter hormonal appetite regulation but can improve the lipid profile in healthy young males. PMID:24887106

High-intensity interval training using whole-body exercises: training recommendations and methodological overview.

PubMed

Machado, Alexandre F; Baker, Julien S; Figueira Junior, Aylton J; Bocalini, Danilo S

2017-05-04

HIIT whole body (HWB)-based exercise is a new calisthenics exercise programme approach that can be considered an effective and safe method to improve physical fitness and body composition. HWB is a method that can be applied to different populations and ages. The purpose of this study was to describe possible methodologies for performing physical training based on whole-body exercise in healthy subjects. The HWB sessions consist of a repeated stimulus based on high-intensity exercise that also include monitoring time to effort, time to recuperation and session time. The exercise intensity is related to the maximal number of movements possible in a given time; therefore, the exercise sessions can be characterized as maximal. The intensity can be recorded using ratings of perceived exertion. Weekly training frequency and exercise selection should be structured according to individual subject functional fitness. Using this simple method, there is potential for greater adherence to physical activity which can promote health benefits to all members of society. © 2017 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

High- and low-intensity exercise do not improve cognitive function after stroke: A randomized controlled trial.

PubMed

Tang, Ada; Eng, Janice J; Krassioukov, Andrei V; Tsang, Teresa S M; Liu-Ambrose, Teresa

2016-11-11

To determine the effects of high versus low-intensity exercise on cognitive function following stroke. Secondary analysis from a randomized controlled trial with blinded assessors. 50-80 years old, living in the community, > 1 year post-stroke. Participants were randomized into a high-intensity Aerobic Exercise or low-intensity non-aerobic Balance/Flexibility program. Both programs were 6 months long, with 3 60-min sessions/week. Verbal item and working memory, selective attention and conflict resolution, set shifting were assessed before and after the program. Forty-seven participants completed the study (22/25 in Aerobic Exercise group, 25/25 in Balance/Flexibility group). There was an improvement in verbal item memory in both groups (time effect p = 0.04), and no between-group differences in improvement in the other outcomes (p > 0.27). There was no association between pre-exercise cognitive function and post-exercise improvement. In contrast to a small body of previous research suggesting positive benefits of exercise on cognition post-stroke, the current study found that 6 months of high or low intensity exercise was not effective in improving cognitive function, specifically executive functions. Further research in this area is warranted to establish the effectiveness of post-stroke exercise programs on cognition, and examine the mechanisms that underlie these changes.

Effect of exercise intensity on postprandial lipemia, markers of oxidative stress, and endothelial function after a high-fat meal.

PubMed

Lopes Krüger, Renata; Costa Teixeira, Bruno; Boufleur Farinha, Juliano; Cauduro Oliveira Macedo, Rodrigo; Pinto Boeno, Francesco; Rech, Anderson; Lopez, Pedro; Silveira Pinto, Ronei; Reischak-Oliveira, Alvaro

2016-12-01

The aim of this study was to compare the effects of 2 different exercise intensities on postprandial lipemia, oxidative stress markers, and endothelial function after a high-fat meal (HFM). Eleven young men completed 2-day trials in 3 conditions: rest, moderate-intensity exercise (MI-Exercise) and heavy-intensity exercise (HI-Exercise). Subjects performed an exercise bout or no exercise (Rest) on the evening of day 1. On the morning of day 2, an HFM was provided. Blood was sampled at fasting (0 h) and every hour from 1 to 5 h during the postprandial period for triacylglycerol (TAG), thiobarbituric acid reactive substance (TBARS), and nitrite/nitrate (NOx) concentrations. Flow-mediated dilatation (FMD) was also analyzed. TAG concentrations were reduced in exercise conditions compared with Rest during the postprandial period (P < 0.004). TAG incremental area under the curve (iAUC) was smaller after HI-Exercise compared with Rest (P = 0.012). TBARS concentrations were reduced in MI-Exercise compared with Rest (P < 0.041). FMD was higher in exercise conditions than Rest at 0 h (P < 0.02) and NOx concentrations were enhanced in MI-Exercise compared with Rest at 0 h (P < 0.01). These results suggest that acute exercise can reduce lipemia after an HFM. However, HI-Exercise showed to be more effective in reducing iAUC TAG, which might suggest higher protection against postprandial TAG enhancement. Conversely, MI-Exercise can be beneficial to attenuate the susceptibility of oxidative damage induced by an HFM and to increase endothelial function in the fasted state compared with Rest.

Repeated sprints, high-intensity interval training, small-sided games: theory and application to field sports.

PubMed

Hoffmann, James J; Reed, Jacob P; Leiting, Keith; Chiang, Chieh-Ying; Stone, Michael H

2014-03-01

Due to the broad spectrum of physical characteristics necessary for success in field sports, numerous training modalities have been used develop physical preparedness. Sports like rugby, basketball, lacrosse, and others require athletes to be not only strong and powerful but also aerobically fit and able to recover from high-intensity intermittent exercise. This provides coaches and sport scientists with a complex range of variables to consider when developing training programs. This can often lead to confusion and the misuse of training modalities, particularly in the development of aerobic and anaerobic conditioning. This review outlines the benefits and general adaptations to 3 commonly used and effective conditioning methods: high-intensity interval training, repeated-sprint training, and small-sided games. The goals and outcomes of these training methods are discussed, and practical implementations strategies for coaches and sport scientists are provided.

Affective Responses to Repeated Sessions of High-Intensity Interval Training.

PubMed

Saanijoki, Tiina; Nummenmaa, Lauri; Eskelinen, Jari-Joonas; Savolainen, Anna M; Vahlberg, Tero; Kalliokoski, Kari K; Hannukainen, Jarna C

2015-12-01

Vigorous exercise feels unpleasant, and negative emotions may discourage adherence to regular exercise. We quantified the subjective affective responses to short-term high-intensity interval training (HIT) in comparison with moderate-intensity continuous training (MIT). Twenty-six healthy middle-age (mean age, 47 ± 5 yr; mean VO2peak, 34.2 ± 4.1 mL·kg⁻¹·min⁻¹) sedentary men were randomized into HIT (n = 13, 4-6 × 30 s of all-out cycling efforts at approximately 180% of peak workload with 4-min recovery) or MIT (n = 13, 40- to 60-min continuous cycling at 60% of peak workload) groups, performing six sessions within two weeks. Perceived exertion, stress, and affective state were recorded before, during, and after each session. Perceived exertion and arousal were higher, and affective state, more negative during the HIT than that during MIT sessions (P < 0.001). HIT versus MIT exercise acutely increased the experience of stress, tension, and irritation and decreased positive affect (P < 0.05). In addition, satisfaction was lower and pain and negative affect were higher in the HIT than those in the MIT group (P < 0.05). However, perceived exertion and displeasure experienced during exercise alleviated similarly in response to HIT and MIT over the 6 d of training. Peak oxygen consumption increased (P < 0.001) after intervention (HIT, 34.7 ± 3.9 vs 36.7 ± 4.5; MIT, 33.9 ± 4.6 vs 35.0 ± 4.6) and was not different between HIT and MIT (P = 0.28 for group × training). Short-term HIT and MIT are equally effective in improving aerobic fitness, but HIT increases experience of negative emotions and exertion in sedentary middle-age men. This may limit the adherence to this time-effective training mode, even though displeasure lessens over time and suggests similar mental adaptations to both MIT and HIT.

Prefrontal cortex haemodynamics and affective responses during exercise: a multi-channel near infrared spectroscopy study.

PubMed

Tempest, Gavin D; Eston, Roger G; Parfitt, Gaynor

2014-01-01

The dose-response effects of the intensity of exercise upon the potential regulation (through top-down processes) of affective (pleasure-displeasure) responses in the prefrontal cortex during an incremental exercise protocol have not been explored. This study examined the functional capacity of the prefrontal cortex (reflected by haemodynamics using near infrared spectroscopy) and affective responses during exercise at different intensities. Participants completed an incremental cycling exercise test to exhaustion. Changes (Δ) in oxygenation (O2Hb), deoxygenation (HHb), blood volume (tHb) and haemoglobin difference (HbDiff) were measured from bilateral dorsal and ventral prefrontal areas. Affective responses were measured every minute during exercise. Data were extracted at intensities standardised to: below ventilatory threshold, at ventilatory threshold, respiratory compensation point and the end of exercise. During exercise at intensities from ventilatory threshold to respiratory compensation point, ΔO2Hb, ΔHbDiff and ΔtHb were greater in mostly ventral than dorsal regions. From the respiratory compensation point to the end of exercise, ΔO2Hb remained stable and ΔHbDiff declined in dorsal regions. As the intensity increased above the ventilatory threshold, inverse associations between affective responses and oxygenation in (a) all regions of the left hemisphere and (b) lateral (dorsal and ventral) regions followed by the midline (ventral) region in the right hemisphere were observed. Differential activation patterns occur within the prefrontal cortex and are associated with affective responses during cycling exercise.

Prefrontal Cortex Haemodynamics and Affective Responses during Exercise: A Multi-Channel Near Infrared Spectroscopy Study

PubMed Central

Tempest, Gavin D.; Eston, Roger G.; Parfitt, Gaynor

2014-01-01

The dose-response effects of the intensity of exercise upon the potential regulation (through top-down processes) of affective (pleasure-displeasure) responses in the prefrontal cortex during an incremental exercise protocol have not been explored. This study examined the functional capacity of the prefrontal cortex (reflected by haemodynamics using near infrared spectroscopy) and affective responses during exercise at different intensities. Participants completed an incremental cycling exercise test to exhaustion. Changes (Δ) in oxygenation (O2Hb), deoxygenation (HHb), blood volume (tHb) and haemoglobin difference (HbDiff) were measured from bilateral dorsal and ventral prefrontal areas. Affective responses were measured every minute during exercise. Data were extracted at intensities standardised to: below ventilatory threshold, at ventilatory threshold, respiratory compensation point and the end of exercise. During exercise at intensities from ventilatory threshold to respiratory compensation point, ΔO2Hb, ΔHbDiff and ΔtHb were greater in mostly ventral than dorsal regions. From the respiratory compensation point to the end of exercise, ΔO2Hb remained stable and ΔHbDiff declined in dorsal regions. As the intensity increased above the ventilatory threshold, inverse associations between affective responses and oxygenation in (a) all regions of the left hemisphere and (b) lateral (dorsal and ventral) regions followed by the midline (ventral) region in the right hemisphere were observed. Differential activation patterns occur within the prefrontal cortex and are associated with affective responses during cycling exercise. PMID:24788166

Mechanical ventilatory constraints during incremental cycle exercise in human pregnancy: implications for respiratory sensation

PubMed Central

Jensen, Dennis; Webb, Katherine A; Davies, Gregory A L; O'Donnell, Denis E

2008-01-01

The aim of this study was to identify the physiological mechanisms of exertional respiratory discomfort (breathlessness) in pregnancy by comparing ventilatory (breathing pattern, airway function, operating lung volumes, oesophageal pressure (Poes)-derived indices of respiratory mechanics) and perceptual (breathlessness intensity) responses to incremental cycle exercise in 15 young, healthy women in the third trimester (TM3; between 34 and 38 weeks gestation) and again 4–5 months postpartum (PP). During pregnancy, resting inspiratory capacity (IC) increased (P < 0.01) and end-expiratory lung volume decreased (P < 0.001), with no associated change in total lung capacity (TLC) or static respiratory muscle strength. This permitted greater tidal volume (VT) expansion throughout exercise in TM3, while preserving the relationship between contractile respiratory muscle effort (tidal Poes swing expressed as a percentage of maximum inspiratory pressure (PImax)) and thoracic volume displacement (VT expressed as a percentage of vital capacity) and between breathlessness and ventilation (V̇E). At the highest equivalent work rate (HEWR = 128 ± 5 W) in TM3 compared with PP: V̇E, tidal Poes/PImax and breathlessness intensity ratings increased by 10.2 l min−1 (P < 0.001), 8.8%PImax (P < 0.05) and 0.9 Borg units (P < 0.05), respectively. Pulmonary resistance was not increased at rest or during exercise at the HEWR in TM3, despite marked increases in mean tidal inspiratory and expiratory flow rates, suggesting increased bronchodilatation. Dynamic mechanical constraints on VT expansion (P < 0.05) with associated increased breathlessness intensity ratings (P < 0.05) were observed near peak exercise in TM3 compared with PP. In conclusion: (1) pregnancy-induced increases in exertional breathlessness reflected the normal awareness of increased V̇E and contractile respiratory muscle effort; (2) mechanical adaptations of the respiratory system, including recruitment of resting IC and increased bronchodilatation, accommodated the increased VT while preserving effort–displacement and breathlessness–V̇E relationships; and (3) dynamic mechanical ventilatory constraints contributed to respiratory discomfort near the limits of tolerance in late gestation. PMID:18687714

Influence of exercise intensity on skeletal muscle blood flow, O2 extraction and O2 uptake on-kinetics

PubMed Central

Jones, Andrew M; Krustrup, Peter; Wilkerson, Daryl P; Berger, Nicolas J; Calbet, José A; Bangsbo, Jens

2012-01-01

Following the start of low-intensity exercise in healthy humans, it has been established that the kinetics of skeletal muscle O2 delivery is faster than, and does not limit, the kinetics of muscle O2 uptake (). Direct data are lacking, however, on the question of whether O2 delivery might limit kinetics during high-intensity exercise. Using multiple exercise transitions to enhance confidence in parameter estimation, we therefore investigated the kinetics of, and inter-relationships between, muscle blood flow (), a– difference and following the onset of low-intensity (LI) and high-intensity (HI) exercise. Seven healthy males completed four 6 min bouts of LI and four 6 min bouts of HI single-legged knee-extension exercise. Blood was frequently drawn from the femoral artery and vein during exercise and , a– difference and were calculated and subsequently modelled using non-linear regression techniques. For LI, the fundamental component mean response time (MRTp) for kinetics was significantly shorter than kinetics (mean ± SEM, 18 ± 4 vs. 30 ± 4 s; P < 0.05), whereas for HI, the MRTp for and was not significantly different (27 ± 5 vs. 29 ± 4 s, respectively). There was no difference in the MRTp for either or between the two exercise intensities; however, the MRTp for a– difference was significantly shorter for HI compared with LI (17 ± 3 vs. 28 ± 4 s; P < 0.05). Excess O2, i.e. oxygen not taken up (×), was significantly elevated within the first 5 s of exercise and remained unaltered thereafter, with no differences between LI and HI. These results indicate that bulk O2 delivery does not limit kinetics following the onset of LI or HI knee-extension exercise. PMID:22711961

Timing of Ibuprofen Use and Bone Mineral Density Adaptations to Exercise Training

PubMed Central

Kohrt, Wendy M; Barry, Daniel W; Van Pelt, Rachael E; Jankowski, Catherine M; Wolfe, Pamela; Schwartz, Robert S

2010-01-01

Prostaglandins (PGs) are essential signaling factors in bone mechanotransduction. In animals, inhibition of the enzyme responsible for PG synthesis (cyclooxygenase) by nonsteroidal anti-inflammatory drugs (NSAIDs) blocks the bone-formation response to loading when administered before, but not immediately after, loading. The aim of this proof-of-concept study was to determine whether the timing of NSAID use influences bone mineral density (BMD) adaptations to exercise in humans. Healthy premenopausal women (n = 73) aged 21 to 40 years completed a supervised 9-month weight-bearing exercise training program. They were randomized to take (1) ibuprofen (400 mg) before exercise, placebo after (IBUP/PLAC), (2) placebo before, ibuprofen after (PLAC/IBUP), or (3) placebo before and after (PLAC/PLAC) exercise. Relative changes in hip and lumbar spine BMD from before to after exercise training were assessed using a Hologic Delphi-W dual-energy X-ray absorptiometry (DXA) instrument. Because this was the first study to evaluate whether ibuprofen use affects skeletal adaptations to exercise, only women who were compliant with exercise were included in the primary analyses (IBUP/PLAC, n = 17; PLAC/PLAC, n = 23; and PLAC/IBUP, n = 14). There was a significant effect of drug treatment, adjusted for baseline BMD, on the BMD response to exercise for regions of the hip (total, p < .001; neck, p = .026; trochanter, p = .040; shaft, p = .019) but not the spine (p = .242). The largest increases in BMD occurred in the group that took ibuprofen after exercise. Total-hip BMD changes averaged –0.2% ± 1.3%, 0.4% ± 1.8%, and 2.1% ± 1.7% in the IBUP/PLAC, PLAC/PLAC, and PLAC/IBUP groups, respectively. This preliminary study suggests that taking NSAIDs after exercise enhances the adaptive response of BMD to exercise, whereas taking NSAIDs before may impair the adaptive response. © 2010 American Society for Bone and Mineral Research. PMID:20200939

Timing of ibuprofen use and bone mineral density adaptations to exercise training.

PubMed

Kohrt, Wendy M; Barry, Daniel W; Van Pelt, Rachael E; Jankowski, Catherine M; Wolfe, Pamela; Schwartz, Robert S

2010-06-01

Prostaglandins (PGs) are essential signaling factors in bone mechanotransduction. In animals, inhibition of the enzyme responsible for PG synthesis (cyclooxygenase) by nonsteroidal anti-inflammatory drugs (NSAIDs) blocks the bone-formation response to loading when administered before, but not immediately after, loading. The aim of this proof-of-concept study was to determine whether the timing of NSAID use influences bone mineral density (BMD) adaptations to exercise in humans. Healthy premenopausal women (n = 73) aged 21 to 40 years completed a supervised 9-month weight-bearing exercise training program. They were randomized to take (1) ibuprofen (400 mg) before exercise, placebo after (IBUP/PLAC), (2) placebo before, ibuprofen after (PLAC/IBUP), or (3) placebo before and after (PLAC/PLAC) exercise. Relative changes in hip and lumbar spine BMD from before to after exercise training were assessed using a Hologic Delphi-W dual-energy X-ray absorptiometry (DXA) instrument. Because this was the first study to evaluate whether ibuprofen use affects skeletal adaptations to exercise, only women who were compliant with exercise were included in the primary analyses (IBUP/PLAC, n = 17; PLAC/PLAC, n = 23; and PLAC/IBUP, n = 14). There was a significant effect of drug treatment, adjusted for baseline BMD, on the BMD response to exercise for regions of the hip (total, p < .001; neck, p = .026; trochanter, p = .040; shaft, p = .019) but not the spine (p = .242). The largest increases in BMD occurred in the group that took ibuprofen after exercise. Total-hip BMD changes averaged -0.2% +/- 1.3%, 0.4% +/- 1.8%, and 2.1% +/- 1.7% in the IBUP/PLAC, PLAC/PLAC, and PLAC/IBUP groups, respectively. This preliminary study suggests that taking NSAIDs after exercise enhances the adaptive response of BMD to exercise, whereas taking NSAIDs before may impair the adaptive response. (c) 2010 American Society for Bone and Mineral Research.

Making muscles "stronger": exercise, nutrition, drugs.

PubMed

Aagaard, P

2004-06-01

As described in this review, maximal muscle strength is strongly influenced by resistive-types of exercise, which induce adaptive changes in both neuromuscular function and muscle morphology. Further, timed intake of protein in conjunction with resistance training elicit greater strength and muscle size gains than resistance training alone. Creatine supplementation amplifies the hypertrophic response to resistance training, although some individuals may not respond positively. Locally produced muscle growth factors are upregulated during creatine supplementation, which contributes to increase the responsiveness of muscle cells to intensive training stimuli. Usage of anabolic steroids boosts muscle hypertrophy beyond inherent genetical limits, not only by increasing the DNA transcription rate for myofibrillar proteins but also by increasing the nucleus-to-cytoplasm ratio due to accelerated activation of myogenic satellite cells. However, severe tissue damaging effects exist with anabolic steroids, some of which are irreversible.

Ergogenic effects of beetroot juice supplementation during severe-intensity exercise in obese adolescents.

PubMed

Rasica, Letizia; Porcelli, Simone; Marzorati, Mauro; Salvadego, Desy; Vezzoli, Alessandra; Agosti, Fiorenza; De Col, Alessandra; Tringali, Gabriella; Jones, Andrew M; Sartorio, Alessandro; Grassi, Bruno

2018-04-25

Previous studies showed a higher O 2 cost of exercise, and therefore a reduced exercise tolerance, in obese patients during constant work rate (CWR) exercise compared to healthy subjects. Among the ergogenic effects of dietary nitrate (NO 3 -) supplementation in sedentary healthy subjects, a reduced O 2 cost and enhanced exercise tolerance have often been demonstrated. The aim of this study was to evaluate the effects of beetroot juice supplementation, rich in NO 3 -, on physiological variables associated with exercise tolerance in obese adolescents. In a double-blind, randomized, crossover study, ten obese adolescents (8F, 2M; age=16{plus minus}1 yr; BMI=35.2{plus minus}5.0 kg.m -2 ) were tested after 6 days of supplementation with beetroot juice (5 mmol NO 3 - per day) (BR) or placebo (PLA). Following each supplementation period, patients carried out two repetitions of 6-min moderate-intensity CWR exercise and one severe-intensity CWR exercise until exhaustion. Plasma NO 3 - concentration was significantly higher in BR vs. PLA (108{plus minus}37 vs. 15{plus minus}5 μM, P<0.0001). The O 2 cost of moderate-intensity exercise was not different in BR vs. PLA (13.3{plus minus}1.7 vs. 12.9{plus minus}1.1 mL.min -1 .W -1 , P=0.517). During severe-intensity exercise, signs of a reduced amplitude of the O 2 uptake slow component were observed in BR, in association with a significantly longer time to exhaustion (561{plus minus}198 s in BR vs. 457{plus minus}101 s in PLA, P=0.0143). In obese adolescents, short-term dietary NO 3 - supplementation is effective in improving exercise tolerance during severe-intensity exercise. This may prove to be useful in contrasting early fatigue and reduced physical activity in this at-risk population.

Exercise Guidelines to Promote Cardiometabolic Health in Spinal Cord Injured Humans: Time to Raise the Intensity?

PubMed

Nightingale, Tom E; Metcalfe, Richard S; Vollaard, Niels B; Bilzon, James L

2017-08-01

Spinal cord injury (SCI) is a life-changing event that, as a result of paralysis, negatively influences habitual levels of physical activity and hence cardiometabolic health. Performing regular structured exercise therefore appears extremely important in persons with SCI. However, exercise options are mainly limited to the upper body, which involves a smaller activated muscle mass compared with the mainly leg-based activities commonly performed by nondisabled individuals. Current exercise guidelines for SCI focus predominantly on relative short durations of moderate-intensity aerobic upper-body exercise, yet contemporary evidence suggests this is not sufficient to induce meaningful improvements in risk factors for the prevention of cardiometabolic disease in this population. As such, these guidelines and their physiological basis require reappraisal. In this special communication, we propose that high-intensity interval training (HIIT) may be a viable alternative exercise strategy to promote vigorous-intensity exercise and prevent cardiometabolic disease in persons with SCI. Supplementing the limited data from SCI cohorts with consistent findings from studies in nondisabled populations, we present strong evidence to suggest that HIIT is superior to moderate-intensity aerobic exercise for improving cardiorespiratory fitness, insulin sensitivity, and vascular function. The potential application and safety of HIIT in this population is also discussed. We conclude that increasing exercise intensity could offer a simple, readily available, time-efficient solution to improve cardiometabolic health in persons with SCI. We call for high-quality randomized controlled trials to examine the efficacy and safety of HIIT in this population. Copyright © 2017 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Re-Examining High-Fat Diets for Sports Performance: Did We Call the 'Nail in the Coffin' Too Soon?

PubMed

Burke, Louise M

2015-11-01

During the period 1985-2005, studies examined the proposal that adaptation to a low-carbohydrate (<25 % energy), high-fat (>60 % energy) diet (LCHF) to increase muscle fat utilization during exercise could enhance performance in trained individuals by reducing reliance on muscle glycogen. As little as 5 days of training with LCHF retools the muscle to enhance fat-burning capacity with robust changes that persist despite acute strategies to restore carbohydrate availability (e.g., glycogen supercompensation, carbohydrate intake during exercise). Furthermore, a 2- to 3-week exposure to minimal carbohydrate (<20 g/day) intake achieves adaptation to high blood ketone concentrations. However, the failure to detect clear performance benefits during endurance/ultra-endurance protocols, combined with evidence of impaired performance of high-intensity exercise via a down-regulation of carbohydrate metabolism led this author to dismiss the use of such fat-adaptation strategies by competitive athletes in conventional sports. Recent re-emergence of interest in LCHF diets, coupled with anecdotes of improved performance by sportspeople who follow them, has created a need to re-examine the potential benefits of this eating style. Unfortunately, the absence of new data prevents a different conclusion from being made. Notwithstanding the outcomes of future research, there is a need for better recognition of current sports nutrition guidelines that promote an individualized and periodized approach to fuel availability during training, allowing the athlete to prepare for competition performance with metabolic flexibility and optimal utilization of all muscle substrates. Nevertheless, there may be a few scenarios where LCHF diets are of benefit, or at least are not detrimental, for sports performance.

Effects of Different Intensities of Exercise on Intraocular Pressure

ERIC Educational Resources Information Center

Rowe, Deryl; And Others

1976-01-01

The decrease in intraocular pressure during exercise and the first few minutes of recovery is related to a decrease in blood pH and an increase in blood lactate concentration, not to the intensity of the exercise. (MB)

Randomized controlled trial of the effects of high intensity and low-to-moderate intensity exercise on physical fitness and fatigue in cancer survivors: results of the Resistance and Endurance exercise After ChemoTherapy (REACT) study.

PubMed

Kampshoff, Caroline S; Chinapaw, Mai J M; Brug, Johannes; Twisk, Jos W R; Schep, Goof; Nijziel, Marten R; van Mechelen, Willem; Buffart, Laurien M

2015-10-29

International evidence-based guidelines recommend physical exercise to form part of standard care for all cancer survivors. However, at present, the optimum exercise intensity is unclear. Therefore, we aimed to evaluate the effectiveness of a high intensity (HI) and low-to-moderate intensity (LMI) resistance and endurance exercise program compared with a wait list control (WLC) group on physical fitness and fatigue in a mixed group of cancer survivors who completed primary cancer treatment, including chemotherapy. Overall, 277 cancer survivors were randomized to 12 weeks of HI exercise (n = 91), LMI exercise (n = 95), or WLC (n = 91). Both interventions were identical with respect to exercise type, duration and frequency, and only differed in intensity. Measurements were performed at baseline (4-6 weeks after primary treatment) and post-intervention. The primary outcomes were cardiorespiratory fitness (peakVO2), muscle strength (grip strength and 30-second chair-stand test), and self-reported fatigue (Multidimensional Fatigue Inventory; MFI). Secondary outcomes included health-related quality of life, physical activity, daily functioning, body composition, mood, and sleep disturbances. Multilevel linear regression analyses were performed to estimate intervention effects using an intention-to-treat principle. In the HI and LMI groups, 74 % and 70 % of the participants attended more than 80 % of the prescribed exercise sessions, respectively (P = 0.53). HI (β = 2.2; 95 % CI, 1.2-3.1) and LMI (β = 1.3; 95 % CI, 0.3-2.3) exercise showed significantly larger improvements in peakVO2 compared to WLC. Improvements in peakVO2 were larger for HI than LMI exercise (β = 0.9; 95 % CI, -0.1 to 1.9), but the difference was not statistically significant (P = 0.08). No intervention effects were found for grip strength and the 30-second chair-stand test. HI and LMI exercise significantly reduced general and physical fatigue and reduced activity (MFI subscales) compared to WLC, with no significant differences between both interventions. Finally, compared to WLC, we found benefits in global quality of life and anxiety after HI exercise, improved physical functioning after HI and LMI exercise, and less problems at work after LMI exercise. Shortly after completion of cancer treatment, both HI and LMI exercise were safe and effective. There may be a dose-response relationship between exercise intensity and peakVO2, favoring HI exercise. HI and LMI exercise were equally effective in reducing general and physical fatigue. This study was registered at the Netherlands Trial Register [ NTR2153 ] on the 5th of January 2010.

The 'Critical Power' Concept: Applications to Sports Performance with a Focus on Intermittent High-Intensity Exercise.

PubMed

Jones, Andrew M; Vanhatalo, Anni

2017-03-01

The curvilinear relationship between power output and the time for which it can be sustained is a fundamental and well-known feature of high-intensity exercise performance. This relationship 'levels off' at a 'critical power' (CP) that separates power outputs that can be sustained with stable values of, for example, muscle phosphocreatine, blood lactate, and pulmonary oxygen uptake ([Formula: see text]), from power outputs where these variables change continuously with time until their respective minimum and maximum values are reached and exercise intolerance occurs. The amount of work that can be done during exercise above CP (the so-called W') is constant but may be utilized at different rates depending on the proximity of the exercise power output to CP. Traditionally, this two-parameter CP model has been employed to provide insights into physiological responses, fatigue mechanisms, and performance capacity during continuous constant power output exercise in discrete exercise intensity domains. However, many team sports (e.g., basketball, football, hockey, rugby) involve frequent changes in exercise intensity and, even in endurance sports (e.g., cycling, running), intensity may vary considerably with environmental/course conditions and pacing strategy. In recent years, the appeal of the CP concept has been broadened through its application to intermittent high-intensity exercise. With the assumptions that W' is utilized during work intervals above CP and reconstituted during recovery intervals below CP, it can be shown that performance during intermittent exercise is related to four factors: the intensity and duration of the work intervals and the intensity and duration of the recovery intervals. However, while the utilization of W' may be assumed to be linear, studies indicate that the reconstitution of W' may be curvilinear with kinetics that are highly variable between individuals. This has led to the development of a new CP model for intermittent exercise in which the balance of W' remaining ([Formula: see text]) may be calculated with greater accuracy. Field trials of athletes performing stochastic exercise indicate that this [Formula: see text] model can accurately predict the time at which W' tends to zero and exhaustion is imminent. The [Formula: see text] model potentially has important applications in the real-time monitoring of athlete fatigue progression in endurance and team sports, which may inform tactics and influence pacing strategy.

Energy-matched moderate and high intensity exercise training improves nonalcoholic fatty liver disease risk independent of changes in body mass or abdominal adiposity - A randomized trial.

PubMed

Winn, Nathan C; Liu, Ying; Rector, R Scott; Parks, Elizabeth J; Ibdah, Jamal A; Kanaley, Jill A

2018-01-01

Exercise training is commonly prescribed for individuals diagnosed with nonalcoholic fatty liver disease (NAFLD); however, consensus regarding the volume and intensity of exercise for optimal benefits is lacking. Thus, we determined whether high intensity interval exercise training (HIIT) produced greater reductions in intrahepatic lipid (IHL) content and NAFLD risk factors compared with energy-matched moderate intensity continuous exercise training (MICT) in obese adults with liver steatosis. Eighteen obese adults were randomized to either 4weeks of HIIT (4min 80% VO 2 peak/3min, 50% VO 2 peak) or MICT (55% VO 2 peak, ~60min), matched for energy expenditure (~400kcal/session) and compared to five non-exercising age-matched control subjects. IHL was measured by 1 H-MRS and frequent blood samples were analyzed for glucose, insulin, c-peptide, and NEFA levels during a liquid meal test (180min) to characterize metabolic phenotype. Baseline body weight, visceral abdominal adiposity, and fasting insulin concentrations were greater in the MICT vs HIIT group (P<0.05), while IHL was tightly matched between MICT and HIIT subjects (P>0.05), albeit higher than control subjects (P<0.01). Visceral abdominal adiposity, body mass, liver aminotransferases (ALT, AST), and hepatic apoptotic/inflammatory markers (cytokeratin 18 and fetuin a) were not reduced with either exercise training intervention (P>0.05). Both HIIT and MICT lowered IHL (HIIT, -37.0±12.4%; MICT, -20.1±6.6%, P<0.05); however, the reduction in IHL was not statistically different between exercise intensities (P=0.25). Furthermore, exercise training decreased postprandial insulin, c-peptide, and lipid peroxidation levels (iAUC, P<0.05). Collectively, these findings indicate that energy-matched high intensity and moderate intensity exercise are effective at decreasing IHL and NAFLD risk that is not contingent upon reductions in abdominal adiposity or body mass. Copyright © 2017 Elsevier Inc. All rights reserved.

Physiologic responses during indoor cycling.

PubMed

Battista, Rebecca A; Foster, Carl; Andrew, Jessica; Wright, Glenn; Lucia, Alejandro; Porcari, John P

2008-07-01

During the last decade, there has been active interest in indoor cycling (e.g., spinning) as a method of choreographed group exercise. Recent studies have suggested that exercise intensity during indoor cycling may be quite high and may transiently exceed Vo2max. This study sought to confirm these findings, as the apparent high intensity of indoor cycling has implications for both the efficacy and the risk of indoor cycling as an exercise method. Twenty healthy female students performed an incremental exercise test to define Vo2max and performed 2 videotaped indoor exercise classes lasting 45 minutes and 35 minutes. Vo2, heart rate (HR), and rating of perceived exertion (RPE) were measured during the indoor cycling classes, with Vo2 data integrated in 30-second intervals. The mean %Vo2max during the indoor cycling classes was modest (74 +/- 14% Vo2max and 66 +/- 14%Vo2max, respectively). However, 52% and 35% of the time during the 45- and 35-minute classes was spent at intensities greater than the ventilatory threshold (VT). The HR response indicated that 35% and 38% of the session time was above the HR associated with VT. In 10 of the 40 exercise sessions, there were segments in which the momentary Vo2 exceeded Vo2max observed during incremental testing, and the cumulative time with exercise intensity greater than Vo2max ranged from 0.5 to 14.0 minutes. It can be concluded that although the intensity of indoor cycling in healthy, physically active women is moderate, there are frequent observations of transient values of Vo2 exceeding Vo2max, and a substantial portion of the exercise bouts at intensities greater than VT. As such, the data suggest that indoor cycling must be considered a high-intensity exercise mode of exercise training, which has implications for both efficacy and risk.

Testosterone Plus Low-Intensity Physical Training in Late Life Improves Functional Performance, Skeletal Muscle Mitochondrial Biogenesis, and Mitochondrial Quality Control in Male Mice

PubMed Central

Guo, Wen; Wong, Siu; Li, Michelle; Liang, Wentao; Liesa, Marc; Serra, Carlo; Jasuja, Ravi; Bartke, Andrzej; Kirkland, James L.; Shirihai, Orian; Bhasin, Shalender

2012-01-01

Testosterone supplementation increases muscle mass in older men but has not been shown to consistently improve physical function and activity. It has been hypothesized that physical exercise is required to induce the adaptations necessary for translation of testosterone-induced muscle mass gain into functional improvements. However, the effects of testosterone plus low intensity physical exercise training (T/PT) on functional performance and bioenergetics are unknown. In this pilot study, we tested the hypothesis that combined administration of T/PT would improve functional performance and bioenergetics in male mice late in life more than low-intensity physical training alone. 28-month old male mice were randomized to receive T/PT or vehicle plus physical training (V/PT) for 2 months. Compare to V/PT control, administration of T/PT was associated with improvements in muscle mass, grip strength, spontaneous physical movements, and respiratory activity. These changes were correlated with increased mitochondrial DNA copy number and expression of markers for mitochondrial biogenesis. Mice receiving T/PT also displayed increased expression of key elements for mitochondrial quality control, including markers for mitochondrial fission-and-fusion and mitophagy. Concurrently, mice receiving T/PT also displayed increased expression of markers for reduced tissue oxidative damage and improved muscle quality. Conclusion: Testosterone administered with low-intensity physical training improves grip strength, spontaneous movements, and respiratory activity. These functional improvements were associated with increased muscle mitochondrial biogenesis and improved mitochondrial quality control. PMID:23240002

Influence of Upper-Body Exercise on the Fatigability of Human Respiratory Muscles

PubMed Central

TILLER, NICHOLAS B.; CAMPBELL, IAN G.; ROMER, LEE M.

2017-01-01

ABSTRACT Purpose Diaphragm and abdominal muscles are susceptible to contractile fatigue in response to high-intensity, whole-body exercise. This study assessed whether the ventilatory and mechanical loads imposed by high-intensity, upper-body exercise would be sufficient to elicit respiratory muscle fatigue. Methods Seven healthy men (mean ± SD; age = 24 ± 4 yr, peak O2 uptake [V˙O2peak] = 31.9 ± 5.3 mL·kg−1·min−1) performed asynchronous arm-crank exercise to exhaustion at work rates equivalent to 30% (heavy) and 60% (severe) of the difference between gas exchange threshold and V˙O2peak. Contractile fatigue of the diaphragm and abdominal muscles was assessed by measuring pre- to postexercise changes in potentiated transdiaphragmatic and gastric twitch pressures (Pdi,tw and Pga,tw) evoked by supramaximal magnetic stimulation of the cervical and thoracic nerves, respectively. Results Exercise time was 24.5 ± 5.8 min for heavy exercise and 9.8 ± 1.8 min for severe exercise. Ventilation over the final minute of heavy exercise was 73 ± 20 L·min−1 (39% ± 11% maximum voluntary ventilation) and 99 ± 19 L·min−1 (53% ± 11% maximum voluntary ventilation) for severe exercise. Mean Pdi,tw did not differ pre- to postexercise at either intensity (P > 0.05). Immediately (5–15 min) after severe exercise, mean Pga,tw was significantly lower than pre-exercise values (41 ± 13 vs 53 ± 15 cm H2O, P < 0.05), with the difference no longer significant after 25–35 min. Abdominal muscle fatigue (defined as ≥15% reduction in Pga,tw) occurred in 1/7 subjects after heavy exercise and 5/7 subjects after severe exercise. Conclusions High-intensity, upper-body exercise elicits significant abdominal, but not diaphragm, muscle fatigue in healthy men. The increased magnitude and prevalence of fatigue during severe-intensity exercise is likely due to additional (nonrespiratory) loading of the thorax. PMID:28288012

Influence of Upper-Body Exercise on the Fatigability of Human Respiratory Muscles.

PubMed

Tiller, Nicholas B; Campbell, Ian G; Romer, Lee M

2017-07-01

Diaphragm and abdominal muscles are susceptible to contractile fatigue in response to high-intensity, whole-body exercise. This study assessed whether the ventilatory and mechanical loads imposed by high-intensity, upper-body exercise would be sufficient to elicit respiratory muscle fatigue. Seven healthy men (mean ± SD; age = 24 ± 4 yr, peak O2 uptake [V˙O2peak] = 31.9 ± 5.3 mL·kg·min) performed asynchronous arm-crank exercise to exhaustion at work rates equivalent to 30% (heavy) and 60% (severe) of the difference between gas exchange threshold and V˙O2peak. Contractile fatigue of the diaphragm and abdominal muscles was assessed by measuring pre- to postexercise changes in potentiated transdiaphragmatic and gastric twitch pressures (Pdi,tw and Pga,tw) evoked by supramaximal magnetic stimulation of the cervical and thoracic nerves, respectively. Exercise time was 24.5 ± 5.8 min for heavy exercise and 9.8 ± 1.8 min for severe exercise. Ventilation over the final minute of heavy exercise was 73 ± 20 L·min (39% ± 11% maximum voluntary ventilation) and 99 ± 19 L·min (53% ± 11% maximum voluntary ventilation) for severe exercise. Mean Pdi,tw did not differ pre- to postexercise at either intensity (P > 0.05). Immediately (5-15 min) after severe exercise, mean Pga,tw was significantly lower than pre-exercise values (41 ± 13 vs 53 ± 15 cm H2O, P < 0.05), with the difference no longer significant after 25-35 min. Abdominal muscle fatigue (defined as ≥15% reduction in Pga,tw) occurred in 1/7 subjects after heavy exercise and 5/7 subjects after severe exercise. High-intensity, upper-body exercise elicits significant abdominal, but not diaphragm, muscle fatigue in healthy men. The increased magnitude and prevalence of fatigue during severe-intensity exercise is likely due to additional (nonrespiratory) loading of the thorax.

Resveratrol supplementation does not augment performance adaptations or fibre-type-specific responses to high-intensity interval training in humans.

PubMed

Scribbans, Trisha D; Ma, Jasmin K; Edgett, Brittany A; Vorobej, Kira A; Mitchell, Andrew S; Zelt, Jason G E; Simpson, Craig A; Quadrilatero, Joe; Gurd, Brendon J

2014-11-01

The present study examined the effect of concurrent exercise training and daily resveratrol (RSV) supplementation (150 mg) on training-induced adaptations following low-dose high-intensity interval training (HIIT). Sixteen recreationally active (∼22 years, ∼51 mL·kg(-1)·min(-1)) men were randomly assigned in a double-blind fashion to either the RSV or placebo group with both groups performing 4 weeks of HIIT 3 days per week. Before and after training, participants had a resting muscle biopsy taken, completed a peak oxygen uptake test, a Wingate test, and a submaximal exercise test. A main effect of training (p < 0.05) and interaction effect (p < 0.05) on peak aerobic power was observed; post hoc pairwise comparisons revealed that a significant (p < 0.05) increase occurred in the placebo group only. Main effects of training (p < 0.05) were observed for both peak oxygen uptake (placebo - pretraining: 51.3 ± 1.8, post-training: 54.5 ± 1.5 mL·kg(-1)·min(-1), effect size (ES) = 0.93; RSV - pretraining: 49.6 ± 2.2, post-training: 52.3 ± 2.5 mL·kg(-1)·min(-1), ES = 0.50) and Wingate peak power (placebo: pretraining: 747 ± 39, post-training: 809 ± 31 W, ES = 0.84; RSV - pretraining: 679 ± 39, post-training: 691 ± 43 W, ES = 0.12). Fibre-type distribution was unchanged, while a main effect of training (p < 0.05) was observed for succinate dehydrogenase activity and glycogen content, but not α-glycerophosphate dehydrogenase activity or intramuscular lipids in type I and IIA fibres. The fold change in PGC-1α, SIRT1, and SOD2 gene expression following training was significantly (p < 0.05) lower in the RSV group than placebo. These results suggest that concurrent exercise training and RSV supplementation may alter the normal training response induced by low-volume HIIT.

Aerobic Exercise Training in Post-Polio Syndrome: Process Evaluation of a Randomized Controlled Trial.

PubMed

Voorn, Eric L; Koopman, Fieke S; Brehm, Merel A; Beelen, Anita; de Haan, Arnold; Gerrits, Karin H L; Nollet, Frans

2016-01-01

To explore reasons for the lack of efficacy of a high intensity aerobic exercise program in post-polio syndrome (PPS) on cardiorespiratory fitness by evaluating adherence to the training program and effects on muscle function. A process evaluation using data from an RCT. Forty-four severely fatigued individuals with PPS were randomized to exercise therapy (n = 22) or usual care (n = 22). Participants in the exercise group were instructed to exercise 3 times weekly for 4 months on a bicycle ergometer (60-70% heart rate reserve). The attendance rate was high (median 89%). None of the participants trained within the target heart rate range during >75% of the designated time. Instead, participants exercised at lower intensities, though still around the anaerobic threshold (AT) most of the time. Muscle function did not improve in the exercise group. Our results suggest that severely fatigued individuals with PPS cannot adhere to a high intensity aerobic exercise program on a cycle ergometer. Despite exercise intensities around the AT, lower extremity muscle function nor cardiorespiratory fitness improved. Improving the aerobic capacity in PPS is difficult through exercise primarily focusing on the lower extremities, and may require a more individualized approach, including the use of other large muscle groups instead. Netherlands National Trial Register NTR1371.

Importance of characteristics and modalities of physical activity and exercise in the management of cardiovascular health in individuals with cardiovascular disease (Part III).

PubMed

Vanhees, L; Rauch, B; Piepoli, M; van Buuren, F; Takken, T; Börjesson, M; Bjarnason-Wehrens, B; Doherty, P; Dugmore, D; Halle, M

2012-12-01

The beneficial effect of exercise training and exercise-based cardiac rehabilitation on symptom-free exercise capacity,cardiovascular and skeletal muscle function, quality of life, general healthy lifestyle, and reduction of depressive symptoms and psychosocial stress is nowadays well recognized. However, it remains largely obscure, which characteristics of physical activity (PA) and exercise training--frequency, intensity, time (duration), type (mode), and volume (dose: intensity x duration) of exercise--are the most effective. The present paper, therefore, will deal with these exercise characteristics in the management of individuals with cardiovascular disease, i.e. coronary artery disease and chronic heart failure patients, but also in patients with congenital or valvular heart disease. Based on the current literature, and if sufficient evidence is available, recommendations from the European Association on Cardiovascular Prevention and Rehabilitation are formulated regarding frequency, intensity, time and type of PA, and safety aspects during exercise inpatients with cardiovascular disease. This paper is the third in a series of three papers, all devoted to the same theme: the importance of the exercise characteristics in the management of cardiovascular health. Part I is directed to the general population and Part II to individuals with cardiovascular risk factors. In general, PA recommendations and exercise training programmes for patients with coronary artery disease or chronic heart failure need to be tailored to the individual's exercise capacity and risk profile, with the aim to reach and maintain the individually highest fitness level possible and to perform endurance exercise training 30–60 min daily (3–5 days per week) in combination with resistance training 2–3 times a week. Because of the frequently reported dose–response relationship between training effect and exercise intensity, one should seek sufficiently high training intensities, although more scientific evidence on effect sizes and safety is warranted. At present, there is insufficient data to give more specific recommendations on type, dosage, and intensity of exercise in some other cardiovascular diseases, such as congenital heart disease, valve disease, cardiomyopathies, channelopathies, and patients with implanted devices.

Sympathetic adaptations to one-legged training

NASA Technical Reports Server (NTRS)

Ray, C. A.

1999-01-01

The purpose of the present study was to determine the effect of leg exercise training on sympathetic nerve responses at rest and during dynamic exercise. Six men were trained by using high-intensity interval and prolonged continuous one-legged cycling 4 day/wk, 40 min/day, for 6 wk. Heart rate, mean arterial pressure (MAP), and muscle sympathetic nerve activity (MSNA; peroneal nerve) were measured during 3 min of upright dynamic one-legged knee extensions at 40 W before and after training. After training, peak oxygen uptake in the trained leg increased 19 +/- 2% (P < 0.01). At rest, heart rate decreased from 77 +/- 3 to 71 +/- 6 beats/min (P < 0.01) with no significant changes in MAP (91 +/- 7 to 91 +/- 11 mmHg) and MSNA (29 +/- 3 to 28 +/- 1 bursts/min). During exercise, both heart rate and MAP were lower after training (108 +/- 5 to 96 +/- 5 beats/min and 132 +/- 8 to 119 +/- 4 mmHg, respectively, during the third minute of exercise; P < 0.01). MSNA decreased similarly from rest during the first 2 min of exercise both before and after training. However, MSNA was significantly less during the third minute of exercise after training (32 +/- 2 to 22 +/- 3 bursts/min; P < 0.01). This training effect on MSNA remained when MSNA was expressed as bursts per 100 heartbeats. Responses to exercise in five untrained control subjects were not different at 0 and 6 wk. These results demonstrate that exercise training prolongs the decrease in MSNA during upright leg exercise and indicates that attenuation of MSNA to exercise reported with forearm training also occurs with leg training.

Effects of exercise on craving and cigarette smoking in the human laboratory.

PubMed

Kurti, Allison N; Dallery, Jesse

2014-06-01

Exercise is increasingly being pursued as a treatment to reduce cigarette smoking. The efficacy of clinical, exercise-based cessation interventions may be enhanced by conducting laboratory studies to determine maximally effective conditions for reducing smoking, and the mechanisms through which the effects on smoking are achieved. The main purpose of this study was to assess whether the effects of exercise on two components of craving (anticipated reward from smoking, anticipated relief from withdrawal) mediated the relationship between exercise and delay (in min) to ad libitum smoking. Experiment 1 (N=21) assessed the effects of exercise intensity (inactivity, low, moderate) on craving components up to 60 min post-exercise. Because moderate-intensity exercise most effectively reduced craving on the reward component, all participants exercised at a moderate intensity in Experiment 2. Using an ABAB within-subjects design, Experiment 2 (N=20) evaluated whether the effects of moderate-intensity exercise on reward and relief components of craving mediated the relationship between exercise and participants' delays (in min) to ad libitum smoking. Delays were significantly longer after exercise (M=21 min) versus inactivity (M=4 min), and the effects of exercise on delay were mediated through the reward component of craving. Future research should continue to explore the mechanisms through which exercise influences behavioral indices of smoking in the human laboratory. Additionally, given the benefits uniquely afforded by exercise-based cessation interventions (e.g., improving mood and other health outcomes), implementing these interventions in clinical settings may contribute substantially to improving public health. Copyright © 2014 Elsevier Ltd. All rights reserved.

Increased atrial arrhythmia susceptibility induced by intense endurance exercise in mice requires TNFα

PubMed Central

Aschar-Sobbi, Roozbeh; Izaddoustdar, Farzad; Korogyi, Adam S.; Wang, Qiongling; Farman, Gerrie P.; Yang, FengHua; Yang, Wallace; Dorian, David; Simpson, Jeremy A.; Tuomi, Jari M.; Jones, Douglas L.; Nanthakumar, Kumaraswamy; Cox, Brian; Wehrens, Xander H.T.; Dorian, Paul; Backx, Peter H.

2015-01-01

Atrial fibrillation (AF) is the most common supraventricular arrhythmia that, for unknown reasons, is linked to intense endurance exercise. Our studies reveal that 6 weeks of swimming or treadmill exercise improves heart pump function and reduces heart-rates. Exercise also increases vulnerability to AF in association with inflammation, fibrosis, increased vagal tone, slowed conduction velocity, prolonged cardiomyocyte action potentials and RyR2 phosphorylation (CamKII-dependent S2814) in the atria, without corresponding alterations in the ventricles. Microarray results suggest the involvement of the inflammatory cytokine, TNFα, in exercised-induced atrial remodelling. Accordingly, exercise induces TNFα-dependent activation of both NFκB and p38MAPK, while TNFα inhibition (with etanercept), TNFα gene ablation, or p38 inhibition, prevents atrial structural remodelling and AF vulnerability in response to exercise, without affecting the beneficial physiological changes. Our results identify TNFα as a key factor in the pathology of intense exercise-induced AF. PMID:25598495

Smartphone-Based Cardiac Rehabilitation Program: Feasibility Study.

PubMed

Chung, Heewon; Ko, Hoon; Thap, Tharoeun; Jeong, Changwon; Noh, Se-Eung; Yoon, Kwon-Ha; Lee, Jinseok

2016-01-01

We introduce a cardiac rehabilitation program (CRP) that utilizes only a smartphone, with no external devices. As an efficient guide for cardiac rehabilitation exercise, we developed an application to automatically indicate the exercise intensity by comparing the estimated heart rate (HR) with the target heart rate zone (THZ). The HR is estimated using video images of a fingertip taken by the smartphone's built-in camera. The introduced CRP app includes pre-exercise, exercise with intensity guidance, and post-exercise. In the pre-exercise period, information such as THZ, exercise type, exercise stage order, and duration of each stage are set up. In the exercise with intensity guidance, the app estimates HR from the pulse obtained using the smartphone's built-in camera and compares the estimated HR with the THZ. Based on this comparison, the app adjusts the exercise intensity to shift the patient's HR to the THZ during exercise. In the post-exercise period, the app manages the ratio of the estimated HR to the THZ and provides a questionnaire on factors such as chest pain, shortness of breath, and leg pain during exercise, as objective and subjective evaluation indicators. As a key issue, HR estimation upon signal corruption due to motion artifacts is also considered. Through the smartphone-based CRP, we estimated the HR accuracy as mean absolute error and root mean squared error of 6.16 and 4.30bpm, respectively, with signal corruption due to motion artifacts being detected by combining the turning point ratio and kurtosis.

Smartphone-Based Cardiac Rehabilitation Program: Feasibility Study

PubMed Central

Chung, Heewon; Yoon, Kwon-Ha; Lee, Jinseok

2016-01-01

We introduce a cardiac rehabilitation program (CRP) that utilizes only a smartphone, with no external devices. As an efficient guide for cardiac rehabilitation exercise, we developed an application to automatically indicate the exercise intensity by comparing the estimated heart rate (HR) with the target heart rate zone (THZ). The HR is estimated using video images of a fingertip taken by the smartphone’s built-in camera. The introduced CRP app includes pre-exercise, exercise with intensity guidance, and post-exercise. In the pre-exercise period, information such as THZ, exercise type, exercise stage order, and duration of each stage are set up. In the exercise with intensity guidance, the app estimates HR from the pulse obtained using the smartphone’s built-in camera and compares the estimated HR with the THZ. Based on this comparison, the app adjusts the exercise intensity to shift the patient’s HR to the THZ during exercise. In the post-exercise period, the app manages the ratio of the estimated HR to the THZ and provides a questionnaire on factors such as chest pain, shortness of breath, and leg pain during exercise, as objective and subjective evaluation indicators. As a key issue, HR estimation upon signal corruption due to motion artifacts is also considered. Through the smartphone-based CRP, we estimated the HR accuracy as mean absolute error and root mean squared error of 6.16 and 4.30bpm, respectively, with signal corruption due to motion artifacts being detected by combining the turning point ratio and kurtosis. PMID:27551969

Physical Activity Assessment Between Consumer- and Research-Grade Accelerometers: A Comparative Study in Free-Living Conditions.

PubMed

Dominick, Gregory M; Winfree, Kyle N; Pohlig, Ryan T; Papas, Mia A

2016-09-19

Wearable activity monitors such as Fitbit enable users to track various attributes of their physical activity (PA) over time and have the potential to be used in research to promote and measure PA behavior. However, the measurement accuracy of Fitbit in absolute free-living conditions is largely unknown. To examine the measurement congruence between Fitbit Flex and ActiGraph GT3X for quantifying steps, metabolic equivalent tasks (METs), and proportion of time in sedentary activity and light-, moderate-, and vigorous-intensity PA in healthy adults in free-living conditions. A convenience sample of 19 participants (4 men and 15 women), aged 18-37 years, concurrently wore the Fitbit Flex (wrist) and ActiGraph GT3X (waist) for 1- or 2-week observation periods (n=3 and n=16, respectively) that included self-reported bouts of daily exercise. Data were examined for daily activity, averaged over 14 days and for minutes of reported exercise. Average day-level data included steps, METs, and proportion of time in different intensity levels. Minute-level data included steps, METs, and mean intensity score (0 = sedentary, 3 = vigorous) for overall reported exercise bouts (N=120) and by exercise type (walking, n=16; run or sports, n=44; cardio machine, n=20). Measures of steps were similar between devices for average day- and minute-level observations (all P values > .05). Fitbit significantly overestimated METs for average daily activity, for overall minutes of reported exercise bouts, and for walking and run or sports exercises (mean difference 0.70, 1.80, 3.16, and 2.00 METs, respectively; all P values < .001). For average daily activity, Fitbit significantly underestimated the proportion of time in sedentary and light intensity by 20% and 34%, respectively, and overestimated time by 3% in both moderate and vigorous intensity (all P values < .001). Mean intensity scores were not different for overall minutes of exercise or for run or sports and cardio-machine exercises (all P values > .05). Fitbit Flex provides accurate measures of steps for daily activity and minutes of reported exercise, regardless of exercise type. Although the proportion of time in different intensity levels varied between devices, examining the mean intensity score for minute-level bouts across different exercise types enabled interdevice comparisons that revealed similar measures of exercise intensity. Fitbit Flex is shown to have measurement limitations that may affect its potential utility and validity for measuring PA attributes in free-living conditions.

Exercise Effects on Fitness and Bone Mineral Density in Early Postmenopausal Women: 1-Year EFOPS Results.

ERIC Educational Resources Information Center

Kemmler, Wolfgang; Engelke, Klaus; Lauber, Dirk; Weineck, Juergen; Hensen, Johannes; Kalender, Willi A.

2002-01-01

Investigated the effect of intense exercise training on physical fitness, coronary heart disease, bone mineral density (BMD), and parameters related to quality of life in early postmenopausal women with osteopenia. Data on woman in control and exercise training groups indicated that the intense exercise training program was effective in improving…

Muscle metabolic and neuromuscular determinants of fatigue during cycling in different exercise intensity domains

PubMed Central

Black, Matthew I.; Jones, Andrew M.; Blackwell, Jamie R.; Bailey, Stephen J.; Wylie, Lee J.; McDonagh, Sinead T. J.; Thompson, Christopher; Kelly, James; Sumners, Paul; Mileva, Katya N.; Bowtell, Joanna L.

2017-01-01

Lactate or gas exchange threshold (GET) and critical power (CP) are closely associated with human exercise performance. We tested the hypothesis that the limit of tolerance (Tlim) during cycle exercise performed within the exercise intensity domains demarcated by GET and CP is linked to discrete muscle metabolic and neuromuscular responses. Eleven men performed a ramp incremental exercise test, 4–5 severe-intensity (SEV; >CP) constant-work-rate (CWR) tests until Tlim, a heavy-intensity (HVY; GET) CWR test until Tlim, and a moderate-intensity (MOD; 0.05) muscle metabolic milieu (i.e., low pH and [PCr] and high [lactate]) was attained at Tlim (approximately 2–14 min) for all SEV exercise bouts. The muscle metabolic perturbation was greater at Tlim following SEV compared with HVY, and also following SEV and HVY compared with MOD (all P < 0.05). The normalized M-wave amplitude for the vastus lateralis (VL) muscle decreased to a similar extent following SEV (−38 ± 15%), HVY (−68 ± 24%), and MOD (−53 ± 29%), (P > 0.05). Neural drive to the VL increased during SEV (4 ± 4%; P < 0.05) but did not change during HVY or MOD (P > 0.05). During SEV and HVY, but not MOD, the rates of change in M-wave amplitude and neural drive were correlated with changes in muscle metabolic ([PCr], [lactate]) and blood ionic/acid-base status ([lactate], [K+]) (P < 0.05). The results of this study indicate that the metabolic and neuromuscular determinants of fatigue development differ according to the intensity domain in which the exercise is performed. NEW & NOTEWORTHY The gas exchange threshold and the critical power demarcate discrete exercise intensity domains. For the first time, we show that the limit of tolerance during whole-body exercise within these domains is characterized by distinct metabolic and neuromuscular responses. Fatigue development during exercise greater than critical power is associated with the attainment of consistent “limiting” values of muscle metabolites, whereas substrate availability and limitations to muscle activation may constrain performance at lower intensities. PMID:28008101

Integrated Physiological Mechanisms of Exercise Performance, Adaptation, and Maladaptation to Heat Stress

DTIC Science & Technology

2011-10-01

performance. We discuss novel systemic (heat acclimation) and cellular ( acquired thermal tolerance) adaptations that improve performance in hot and...cellular ( acquired thermal tolerance) adaptations that improve perfor- mance in hot and temperate environments and protect organs from heat stroke as...performance; (iii) newly identified adaptations associated with heat accli- mation/ acquired thermal tolerance that impact exercise-heat tolerance; (iv

Effects of exercise on the desire to smoke and physiological responses to temporary smoking abstinence: a crossover trial.

PubMed

Roberts, Vaughan; Gant, Nicholas; Sollers, John J; Bullen, Chris; Jiang, Yannan; Maddison, Ralph

2015-03-01

Exercise has been shown to attenuate cigarette cravings during temporary smoking abstinence; however, the mechanisms of action are not clearly understood. The objectives of the study were to compare the effects of three exercise intensities on desire to smoke and explore potential neurobiological mediators of desire to smoke. Following overnight abstinence, 40 participants (25 males, 18-59 years) completed three 15 min sessions of light-, moderate-, or vigorous-intensity exercise on a cycle ergometer in a randomized crossover design. Ratings of desire to smoke were self-reported pre- and post-exercise and heart rate variability was measured throughout. Saliva and blood were analyzed for cortisol and noradrenaline in a sub-sample. Exercise influenced desire to smoke (F [2, 91] = 7.94, p < 0.01), with reductions greatest immediately after vigorous exercise. There were also significant time x exercise intensity interaction effects for heart rate variability and plasma noradrenaline (F [8, 72] = 2.23, p = 0.03), with a bias in noradrenaline occurring between light and vigorous conditions (adjusted mean difference [SE] = 2850 ng/ml [592], p < 0.01) at 5 min post-exercise. There was no interaction of time x exercise intensity for plasma and salivary cortisol levels. These findings support the use of vigorous exercise to reduce cigarette cravings, showing potential alterations in a noradrenergic marker.

Irisin in response to exercise in humans with and without metabolic syndrome.

PubMed

Huh, Joo Young; Siopi, Aikaterina; Mougios, Vassilis; Park, Kyung Hee; Mantzoros, Christos S

2015-03-01

Irisin is a recently identified exercise-induced myokine. However, the circulating levels of irisin in response to different types of exercise in subjects with metabolic syndrome are unknown. This study aimed to study the levels of irisin in healthy males and subjects with metabolic syndrome at baseline and in response to exercise. Each individual completed high-intensity interval exercise (HIIE), continuous moderate-intensity exercise (CME), and resistance exercise (RE) sessions in a random, crossover design. Percentage change in circulating irisin levels was examined. Two different irisin assays were used to compare the results of the RE study. Circulating irisin increased immediately after HIIE, CME, and RE and declined 1 hour later. The increase was greater in response to resistance compared with either high-intensity intermittent exercise or CME. Change in irisin in response to exercise did not differ between individuals with and without metabolic syndrome. Exercise is able to increase circulating irisin levels in individuals with the metabolic syndrome as well as healthy individuals. Whether this increase may contribute to the beneficial effects of exercise on patients with the metabolic syndrome remains to be studied further.

Effects of Exercise Intervention on Preventing Letrozole-Exposed Rats From Polycystic Ovary Syndrome.

PubMed

Cao, Si-Fan; Hu, Wen-Long; Wu, Min-Min; Jiang, Li-Yan

2017-03-01

Polycystic ovary syndrome (PCOS) is a prevalent endocrinological disorder in reproductive-age women and is often associated with a metabolic syndrome. To investigate whether exercise intervention promotes PCOS prevention, a rat model was used. Polycystic ovary syndrome was induced by letrozole administration, and animals presented with obesity, sex hormone disorder, no ovulation, large cystic follicles, and increasing fasting insulin (FINS) and leptin levels. The intervention was set at 3 different intensities of swimming exercise: low (0.5 h/d), moderate (1 h/d), and high (2 h/d), and compared with a PCOS model group (letrozole administration without exercise intervention) and a control group. The exercise intervention in the low-intensity group did not produce changes in obesity, testosterone, progesterone (P), and follicle-stimulating hormone (FSH) levels. Moderate-intensity exercise reduced body weight, retained ovulation, and P levels were increased but remained lower than those in the control group. The FSH levels were significantly higher, and FINS and leptin levels were lower than in the model group ( P < 0.05) but not in the control group. The high-intensity group demonstrated the greatest effect of PCOS prevention. Testosterone, luteinizing hormone, FINS, and leptin levels were significantly lower in the high-intensity group, and FSH and P levels were higher compared with the model group. These results suggest that high-intensity exercise intervention can effectively prevent PCOS development.

Differences in the Intensity and Duration of Adolescents' Sports and Exercise across Physical and Social Environments

ERIC Educational Resources Information Center

Dunton, Genevieve Fridlund; Berrigan, David; Ballard-Barbash, Rachel; Perna, Frank; Graubard, Barry I.; Atienza, Audie A.

2012-01-01

We used data from the American Time Use Survey (years 2003-06) to analyze whether the intensity and duration of high school students' (ages 15-18 years) sports and exercise bouts differed across physical and social environments. Boys' sports and exercise bouts were more likely to reach a vigorous intensity when taking place at school and with…

Within-session responses to high-intensity interval training in spinal cord injury.

PubMed

Astorino, Todd Anthony; Thum, Jacob S

2018-02-01

Completion of high-intensity interval training (HIIT) increases maximal oxygen uptake and health status, yet its feasibility in persons with spinal cord injury is unknown. To compare changes in cardiorespiratory and metabolic variables between two interval training regimes and moderate intensity exercise. Nine adults with spinal cord injury (duration = 6.8 ± 6.2 year) initially underwent determination of peak oxygen uptake. During subsequent sessions, they completed moderate intensity exercise, HIIT, or sprint interval training. Oxygen uptake, heart rate, and blood lactate concentration were measured. Oxygen uptake and heart rate increased (p < 0.05) during both interval training sessions and were similar (p > 0.05) to moderate intensity exercise. Peak oxygen uptake and heart rate were higher (p < 0.05) with HIIT (90% peak oxygen uptake and 99% peak heart rate) and sprint interval training (80% peak oxygen uptake and 96% peak heart rate) versus moderate intensity exercise. Despite a higher intensity and peak cardiorespiratory strain, all participants preferred interval training versus moderate exercise. Examining long-term efficacy and feasibility of interval training in this population is merited, considering that exercise intensity is recognized as the most important variable factor of exercise programming to optimize maximal oxygen uptake. Implications for Rehabilitation Spinal cord injury (SCI) reduces locomotion which impairs voluntary physical activity, typically resulting in a reduction in peak oxygen uptake and enhanced chronic disease risk. In various able-bodied populations, completion of high-intensity interval training (HIIT) has been consistently reported to improve cardiorespiratory fitness and other health-related outcomes, although its efficacy in persons with SCI is poorly understood. Data from this study in 9 men and women with SCI show similar changes in oxygen uptake and heart in response to HIIT compared to a prolonged bout of aerobic exercise, although peak values were higher in response to HIIT. Due to the higher peak metabolic strain induced by HIIT as well as universal preference for this modality versus aerobic exercise as reported in this study, further work testing utility of HIIT in this population is merited.

Effect of Local Vibration and Passive Exercise on the Hormones and Neurotransmitters of Hypothalamic-Pituitary-Adrenal Axis in Hindlimb Unloading Rats

NASA Astrophysics Data System (ADS)

Luan, Huiqin; Huang, Yunfei; Li, Jian; Sun, Lianwen; Fan, Yubo

2018-04-01

Astronauts are severely affected by spaceflight-induced bone loss. Mechanical stimulation through exercise inhibits bone resorption and improves bone formation. Exercise and vibration can prevent the degeneration of the musculoskeletal system in tail-suspended rats, and long-term exercise stress will affect endocrine and immune systems that are prone to fatigue. However, the mechanisms through which exercise and vibration affect the endocrine system remain unknown. This study mainly aimed to investigate the changes in the contents of endocrine axis-related hormones and the effects of local vibration and passive exercise on hypothalamic-pituitary-adrenal (HPA) axis-related hormones in tail-suspended rats. A total of 32 Sprague-Dawley rats were randomly distributed into four groups (n = 8 per group): tail suspension (TS), TS + 35Hz vibration, TS + passive exercise, and control. The rats were placed on a passive exercise and local vibration regimen for 21 days. On day 22 of the experiment, the contents of corticotrophin-releasing hormone, adrenocorticotropic hormone, cortisol, and 5-hydroxytryptamine in the rats were quantified with kits in accordance with the manufacturer's instructions. Histomorphometry was applied to evaluate histological changes in the hypothalamus. Results showed that 35Hz local vibration cannot cause rats to remain in a stressed state and that it might not inhibit the function of the HPA axis. Therefore, we speculate that this local vibration intensity can protect the function of the HPA axis and helps tail-suspended rats to transition from stressed to adaptive state.

Anaerobic threshold employed on exercise training prescription and performance assessment for laboratory rodents: A short review.

PubMed

Abreu, Phablo; Mendes, Sávio Victor Diogenes; Leal-Cardoso, José Henrique; Ceccatto, Vânia Marilande

2016-04-15

Several studies have generated numerous terms in the field of exercise training prescription and performance assessment that often do not match the information previously demonstrated by many other works, generating much debate and resulting in an immense pool of scientific results. Several protocols in exercise training prescription and performance assessment have been proposed for these purposes by many reasons. In the field of exercise science, the protocol must be thoroughly investigated and provide real tools to be reproducible. Many laboratories have been adapting and developing evaluation protocols and testing on physical training of rodents in different experimental conditions. In this context, mice, rats and rabbits are preferentially chosen due to easy manipulation and good response to exercise, and comparable at results obtained with humans in compatible effort intensities. But, the exercise training programs and aerobic-anaerobic transition assessment proposed for animal models vary extensively, depending on the species, gender, age, type of stimulus, type of exercise, type of method and also on the specific objectives of the program. This short review demonstrates the need in offering tools performed by invasive measurement to assess the anaerobic threshold by blood lactate employed on evolution of aerobic-anaerobic parameters of rodents. The objective of this short review was to present and to discuss physical evaluation protocols applications to rodents. The table submitted may give a basis for anaerobic threshold employed on exercise training prescription and performance assessment for laboratory rodents in future research. Copyright © 2016 Elsevier Inc. All rights reserved.

High Intensity Interval Training for Maximizing Health Outcomes.

PubMed

Karlsen, Trine; Aamot, Inger-Lise; Haykowsky, Mark; Rognmo, Øivind

Regular physical activity and exercise training are important actions to improve cardiorespiratory fitness and maintain health throughout life. There is solid evidence that exercise is an effective preventative strategy against at least 25 medical conditions, including cardiovascular disease, stroke, hypertension, colon and breast cancer, and type 2 diabetes. Traditionally, endurance exercise training (ET) to improve health related outcomes has consisted of low- to moderate ET intensity. However, a growing body of evidence suggests that higher exercise intensities may be superior to moderate intensity for maximizing health outcomes. The primary objective of this review is to discuss how aerobic high-intensity interval training (HIIT) as compared to moderate continuous training may maximize outcomes, and to provide practical advices for successful clinical and home-based HIIT. Copyright © 2017. Published by Elsevier Inc.

Teaching Students How to Analyze and Adapt to Audiences

ERIC Educational Resources Information Center

Seiter, John S.; Gass, Robert H.

2007-01-01

This article describes an exercise that involves providing students with a basic understanding and demonstration of audience adaptation and then asking them to practice and evaluate the skill. In this exercise the instructor begins by providing students with background on analyzing and adapting to audiences. Then the instructor collects several…

Exercise and Self-Reported Limitations in Patients with Inflammatory Bowel Disease.

PubMed

DeFilippis, Ersilia M; Tabani, Saniya; Warren, Ryan U; Christos, Paul J; Bosworth, Brian P; Scherl, Ellen J

2016-01-01

Limited evidence suggests that exercise may have beneficial, anti-inflammatory effects in patients with inflammatory bowel disease (IBD). The purpose of this study was to evaluate the prevalence of exercise in patients with IBD and the limitations they experience secondary to their disease. Two hundred and fifty IBD patients were prospectively enrolled in this study at an academic medical center at the time of their outpatient visits between March and October 2013. Subjects were asked to complete a one-time survey that asks questions about medical and surgical history, exercise frequency and intensity, and the limitations and barriers they experience. Two hundred and twenty-seven patients (148 female patients) completed the survey. Crohn's disease was present in 140 patients (61.5 %), while 87 had ulcerative colitis. Forty-one patients (16.4 %) never exercised, 82 patients (32.8 %) exercised 1-2 times per week, 59 (23.6 %) exercised 3-4 times per week, and 45 (18.0 %) exercised more than four times per week. Of the 186 who regularly exercise, 95 (51 %) reported moderate exercise intensity, 61 (33 %) reported light intensity, and 30 (16 %) reported vigorous intensity. Ninety-nine patients (44 %) reported that their IBD limited their exercise for reasons including fatigue (n = 81), joint pain (n = 37), embarrassment (n = 23), weakness (n = 21), and others. Although they may benefit from exercise, IBD patients experience considerable barriers to regular exercise secondary to the relapsing and remitting nature of IBD. Larger studies are needed to determine the effects of exercise on disease symptomatology and activity.

Kinetic Analysis of Horizontal Plyometric Exercise Intensity.

PubMed

Kossow, Andrew J; Ebben, William P

2018-05-01

Kossow, AJ, DeChiara, TG, Neahous, SM, and Ebben, WP. Kinetic analysis of horizontal plyometric exercise intensity. J Strength Cond Res 32(5): 1222-1229, 2018-Plyometric exercises are frequently performed as part of a strength and conditioning program. Most studies assessed the kinetics of plyometric exercises primarily performed in the vertical plane. The purpose of this study was to evaluate the multiplanar kinetic characteristics of a variety of plyometric exercises, which have a significant horizontal component. This study also sought to assess sex differences in the intensity progression of these exercises. Ten men and 10 women served as subjects. The subjects performed a variety of plyometric exercises including the double-leg hop, standing long jump, single-leg standing long jump, bounding, skipping, power skipping, cone hops, and 45.72-cm hurdle hops. Subjects also performed the countermovement jump for comparison. All plyometric exercises were evaluated using a force platform. Dependent variables included the landing rate of force development and landing ground reaction forces for each exercise in the vertical, frontal, and sagittal planes. A 2-way mixed analysis of variance with repeated-measures for plyometric exercise type demonstrated main effects for exercise type for all dependent variables (p ≤ 0.001). There was no significant interaction between plyometric exercise type and sex for any of the variable assessed. Bonferroni-adjusted pairwise comparisons identified a number of differences between the plyometric exercises for the dependent variables assessed (p ≤ 0.05). These findings should be used to guide practitioners in the progression of plyometric exercise intensity, and thus program design, for those who require significant horizontal power in their sport.

Strength and Cardiorespiratory Exercise Rehabilitation for Severely Burned Patients During Intensive Care Units: A Survey of Practice.

PubMed

Cambiaso-Daniel, Janos; Parry, Ingrid; Rivas, Eric; Kemp-Offenberg, Jennifer; Sen, Soman; Rizzo, Julie A; Serghiou, Michael A; Kowalske, Karen; Wolf, Steven E; Herndon, David N; Suman, Oscar E

2018-03-22

Minimizing the deconditioning of burn injury through early rehabilitation programs (RP) in the intensive care unit (ICU) is of importance for improving the recovery time. The aim of this study was to assess current standard of care (SOC) for early ICU exercise programs in major burn centers. We designed a survey investigating exercise RP on the ICU for burn patients with >30% total burned surface area. The survey was composed of 23 questions and submitted electronically via SurveyMonkey® to six major (pediatric and adult) burn centers in Texas and California. All centers responded and reported exercise as part of their RP on the ICU. The characteristics of exercises implemented were not uniform. All centers reported to perform resistive and aerobic exercises but only 83% reported isotonic and isometric exercises. Determination of intensity of exercise varied with 50% of centers using patient tolerance and 17% using vital signs. Frequency of isotonic, isometric, aerobic, and resistive exercise was reported as daily by 80%, 80%, 83%, and 50% of centers, respectively. Duration for all types of exercises was extremely variable. Mobilization was used as a form of exercise by 100% of burn centers. Our results demonstrate that although early RP seem to be integral during burn survivor's ICU stay, no SOC exists. Moreover, early RP are inconsistently administered and large variations exist in frequency, intensity, duration, and type of exercise. Thus, future prospective studies investigating the various components of exercise interventions are needed to establish a SOC and determine how and if early exercise benefits the burn survivor.

Heat Acclimation by Post-Exercise Hot Water Immersion in the Morning Reduces Thermal Strain During Morning and Afternoon Exercise-Heat-Stress.

PubMed

Zurawlew, Michael J; Mee, Jessica A; Walsh, Neil P

2018-05-10

Recommendations state that to acquire the greatest benefit from heat acclimation the clock-time of heat acclimation sessions should match the clock-time of expected exercise-heat stress. It remains unknown if adaptations by post-exercise hot water immersion (HWI) demonstrate time of day dependent adaptations. Thus, we examined whether adaptations following post-exercise HWI completed in the morning were present during morning and afternoon exercise-heat stress. Ten males completed an exercise-heat stress test commencing in the morning (0945-h: AM) and afternoon (1445-h: PM; 40 min; 65% V̇O 2max treadmill run) before (PRE) and after (POST) heat acclimation. The 6-day heat acclimation intervention involved a daily, 40 min treadmill-run (65% V̇O 2max ) in temperate conditions followed by ≤ 40 min HWI (40°C; 0630-1100-h). Adaptations by 6-day post-exercise HWI in the morning were similar in the morning and afternoon. Reductions in resting rectal temperature (T re ; AM; -0.34 ± 0.24°C, PM; -0.27 ± 0.23°C; P = 0.002), T re at sweating onset (AM; -0.34 ± 0.24°C, PM; -0.31 ± 0.25°C; P = 0.001), and end-exercise T re (AM; -0.47 ± 0.33°C, PM; -0.43 ± 0.29°C; P = 0.001), heart rate (AM; -14 ± 7 beats∙min -1 , PM; -13 ± 6 beats∙min -1 ; P < 0.01), rating of perceived exertion (P = 0.01), and thermal sensation (P = 0.005) were not different in the morning compared to the afternoon. Morning heat acclimation by post-exercise hot water immersion induced adaptions at rest and during exercise-heat stress in the morning and mid-afternoon.

Locomotor, cardiocirculatory and metabolic adaptations to training in Andalusian and Anglo-Arabian horses.

PubMed

Muñoz, A; Santisteban, R; Rubio, M D; Agüera, E I; Escribano, B M; Castejón, F M

1999-02-01

The effects of two training programmes in 20 Andalusian and 12 Anglo-Arabian horses were evaluated by an increasing intensity work test at velocities of 4, 5, 6, 7 and 8 m sec(-1). Heart rate was monitored and blood samples were drawn at rest and after each velocity to analyse packed cell volume, haemoglobin concentration, plasma lactate and potassium levels. Furthermore, the programmes were video-taped and stride length, duration and frequency, stance (restraint and propulsion), swing phase durations and stride vertical component were measured. The training protocol of the Andalusian horses produced significant decreases in the cardiovascular, haematological and metabolic responses to exercise. Locomotory training adaptation consisted of an increased stride frequency and a reduced stride length and vertical stride component. The last variable was the limiting factor of stride length both before and after training in the Andalusian horses. A different training protocol for show-jumping competition in Anglo-Arabian horses failed to show significant differences in the studied parameters to the work test, although an increase in stride length at velocities of over 6 m sec(-1) was observed. Stride vertical component did not have an effect on the physiological response to exercise, either before or after training.

Do 'mind over muscle' strategies work? Examining the effects of attentional association and dissociation on exertional, affective and physiological responses to exercise.

PubMed

Lind, Erik; Welch, Amy S; Ekkekakis, Panteleimon

2009-01-01

Despite the well established physical and psychological benefits derived from leading a physically active life, rates of sedentary behaviour remain high. Dropout and non-compliance are major contributors to the problem of physical inactivity. Perceptions of exertion, affective responses (e.g. displeasure or discomfort), and physiological stress could make the exercise experience aversive, particularly for beginners. Shifting one's attentional focus towards environmental stimuli (dissociation) instead of one's body (association) has been theorized to enhance psychological responses and attenuate physiological stress. Research evidence on the effectiveness of attentional focus strategies, however, has been perplexing, covering the entire gamut of possible outcomes (association and dissociation having been shown to be both effective and ineffective). This article examines the effects of manipulations of attentional focus on exertional and affective responses, as well as on exercise economy and tolerance. The possible roles of the characteristics of the exercise stimulus (intensity, duration) and the exercise participants, methodological issues, and limitations of experimental designs are discussed. In particular, the critical role of exercise intensity is emphasized. Dissociative strategies may be more effective in reducing perceptions of exertion and enhancing affective responses at low to moderate exercise intensities, but their effectiveness may be diminished at higher and near-maximal levels, at which physiological cues dominate. Conversely, associative strategies could enable the exerciser to regulate intensity to avoid injury or overexertion. Thus, depending on intensity, both strategies have a place in the 'toolbox' of the public health or exercise practitioner as methods of enhancing the exercise experience and promoting long-term compliance.