Hematological variations at rest and during maximal and submaximal exercise in a cold (0°C) environment

NASA Astrophysics Data System (ADS)

Vogelaere, P.; Brasseur, M.; Quirion, A.; Leclercq, R.; Laurencelle, L.; Bekaert, S.

1990-03-01

The affect of negative thermal stress on hematological variables at rest, and during submaximal (sub ex) and maximal exercise (max ex) were observed for young males who volunteered in two experimental sessions, performed in cold (0°C) and in normal room temperature (20°C). At rest, hematological variables such as RBC and derivates Hb and Hct were significantly increased ( P<0.05) during cold stress exposure, while plasma volume decreased. The findings of this study suggest that the major factor inducing hypovolemia during low thermal stress can be imputed to local plasma water-shift mechanisms and especially to a transient shift of plasma water from intrato extravascular compartments. Rest values for WBC and platelets (Pla) were also slightly increased during cold stress exposure. However this increase can partly be related to hemoconcentration but also to the cold induced hyperventilation activating the lung circulation. Maximal exhaustive exercise induced, in both experimental temperatures, significant ( P<0.05) increments of RBC, Hb, Hct, and WBC while plasma volume decreased. However, Pla increase was less marked. On the other hand, cold stress raised slightly the observed variations of the different hematological variables. Submaximal exercise induced a similar, though non-significant, pattern for the different hematological variables in both experimental conditions. Observed plasma volume (Δ PV%) reduction appears during exercise. However cold stress induced resting plasma volume variations that are transferred at every exercise level. Neither exercise nor cold inducement significantly modified the hematological indices (MCH, MCV, MCHC). In conclusion hematological variables are affected by cold stress exposure, even when subjects perform a physical activity.

The TRPC1 Ca2+-permeable channel inhibits exercise-induced protection against high-fat diet-induced obesity and type II diabetes.

PubMed

Krout, Danielle; Schaar, Anne; Sun, Yuyang; Sukumaran, Pramod; Roemmich, James N; Singh, Brij B; Claycombe-Larson, Kate J

2017-12-15

The transient receptor potential canonical channel-1 (TRPC1) is a Ca 2+ -permeable channel found in key metabolic organs and tissues, including the hypothalamus, adipose tissue, and skeletal muscle. Loss of TRPC1 may alter the regulation of cellular energy metabolism resulting in insulin resistance thereby leading to diabetes. Exercise reduces insulin resistance, but it is not known whether TRPC1 is involved in exercise-induced insulin sensitivity. The role of TRPC1 in adiposity and obesity-associated metabolic diseases has not yet been determined. Our results show that TRPC1 functions as a major Ca 2+ entry channel in adipocytes. We have also shown that fat mass and fasting glucose concentrations were lower in TRPC1 KO mice that were fed a high-fat (HF) (45% fat) diet and exercised as compared with WT mice fed a HF diet and exercised. Adipocyte numbers were decreased in both subcutaneous and visceral adipose tissue of TRPC1 KO mice fed a HF diet and exercised. Finally, autophagy markers were decreased and apoptosis markers increased in TRPC1 KO mice fed a HF diet and exercised. Overall, these findings suggest that TRPC1 plays an important role in the regulation of adiposity via autophagy and apoptosis and that TRPC1 inhibits the positive effect of exercise on type II diabetes risk under a HF diet-induced obesity environment.

Effects of Physical Activity and Ginkgo Biloba on Cognitive Function and Oxidative Stress Modulation in Ischemic Rats.

PubMed

Vaghef, Ladan; Bafandeh Gharamaleki, Hassan

2017-09-01

Either exercise or Ginkgo biloba is reported to improve cognitive functioning. The aim of this study is to compare the protective effects of forced exercise and Ginkgo biloba on oxidative stress as well as memory impairments induced by transient cerebral ischemia. Adult male Wistar rats were treated with treadmill running or Ginkgo biloba extract for 2 weeks before cerebral ischemia. Memory was assessed using a Morris water maze (MWM) task. At the end of the behavioral testing, oxidative stress biomarkers were evaluated in the hippocampus tissue. As expected, the cerebral ischemia induced memory impairment in the MWM task, and oxidative stress in the hippocampus. These effects were significantly prevented by treadmill running. Indeed, it ameliorated oxidative stress and memory deficits induced by ischemia. In contrast, Ginkgo biloba was not as effective as exercise in preventing ischemia-induced memory impairments. The results confirmed the neuroprotective effects of treadmill running on hippocampus-dependent memory.

Exercise-Induced Oxidative Stress Responses in the Pediatric Population

PubMed Central

Avloniti, Alexandra; Chatzinikolaou, Athanasios; Deli, Chariklia K.; Vlachopoulos, Dimitris; Gracia-Marco, Luis; Leontsini, Diamanda; Draganidis, Dimitrios; Jamurtas, Athanasios Z.; Mastorakos, George; Fatouros, Ioannis G.

2017-01-01

Adults demonstrate an upregulation of their pro- and anti-oxidant mechanisms in response to acute exercise while systematic exercise training enhances their antioxidant capacity, thereby leading to a reduced generation of free radicals both at rest and in response to exercise stress. However, less information exists regarding oxidative stress responses and the underlying mechanisms in the pediatric population. Evidence suggests that exercise-induced redox perturbations may be valuable in order to monitor exercise-induced inflammatory responses and as such training overload in children and adolescents as well as monitor optimal growth and development. The purpose of this review was to provide an update on oxidative stress responses to acute and chronic exercise in youth. It has been documented that acute exercise induces age-specific transient alterations in both oxidant and antioxidant markers in children and adolescents. However, these responses seem to be affected by factors such as training phase, training load, fitness level, mode of exercise etc. In relation to chronic adaptation, the role of training on oxidative stress adaptation has not been adequately investigated. The two studies performed so far indicate that children and adolescents exhibit positive adaptations of their antioxidant system, as adults do. More studies are needed in order to shed light on oxidative stress and antioxidant responses, following acute exercise and training adaptations in youth. Available evidence suggests that small amounts of oxidative stress may be necessary for growth whereas the transition to adolescence from childhood may promote maturation of pro- and anti-oxidant mechanisms. Available evidence also suggests that obesity may negatively affect basal and exercise-related antioxidant responses in the peripubertal period during pre- and early-puberty. PMID:28106721

Data and results of a laboratory investigation of microprocessor upset caused by simulated lightning-induced analog transients

NASA Technical Reports Server (NTRS)

Belcastro, C. M.

1984-01-01

A methodology was developed a assess the upset susceptibility/reliability of a computer system onboard an aircraft flying through a lightning environment. Upset error modes in a general purpose microprocessor were studied. The upset tests involved the random input of analog transients which model lightning induced signals onto interface lines of an 8080 based microcomputer from which upset error data was recorded. The program code on the microprocessor during tests is designed to exercise all of the machine cycles and memory addressing techniques implemented in the 8080 central processing unit. A statistical analysis is presented in which possible correlations are established between the probability of upset occurrence and transient signal inputs during specific processing states and operations. A stochastic upset susceptibility model for the 8080 microprocessor is presented. The susceptibility of this microprocessor to upset, once analog transients have entered the system, is determined analytically by calculating the state probabilities of the stochastic model.

Exercise and Glycemic Control: Focus on Redox Homeostasis and Redox-Sensitive Protein Signaling

PubMed Central

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

2017-01-01

Physical inactivity, excess energy consumption, and obesity are associated with elevated systemic oxidative stress and the sustained activation of redox-sensitive stress-activated protein kinase (SAPK) and mitogen-activated protein kinase signaling pathways. Sustained SAPK activation leads to aberrant insulin signaling, impaired glycemic control, and the development and progression of cardiometabolic disease. Paradoxically, acute exercise transiently increases oxidative stress and SAPK signaling, yet postexercise glycemic control and skeletal muscle function are enhanced. Furthermore, regular exercise leads to the upregulation of antioxidant defense, which likely assists in the mitigation of chronic oxidative stress-associated disease. In this review, we explore the complex spatiotemporal interplay between exercise, oxidative stress, and glycemic control, and highlight exercise-induced reactive oxygen species and redox-sensitive protein signaling as important regulators of glucose homeostasis. PMID:28529499

VO2 kinetics of constant-load exercise following bed-rest-induced deconditioning

NASA Technical Reports Server (NTRS)

Convertino, V. A.; Goldwater, D. J.; Sandler, H.

1984-01-01

Previous studies have shown that the oxygen uptake kinetics during exercise and recovery may be changed by alterations in work intensity, prior exercise, muscle group involvement, ambient conditions, posture, disease state, and level of physical conditioning. However, the effects of detraining on oxygen uptake kinetics have not been determined. The present investigation has the objective to determine the effects of deconditioning following seven days of continuous head-down bed rest on changes in steady-state oxygen uptake, O2 deficit, and recovery oxygen uptake during the performance of constant-load exercise. The obtained results may provide support for previous proposals that submaximal oxygen uptake was significantly reduced following bed rest. The major finding was that bed-rest deconditioning resulted in a reduction of total O2 transport/utilization capacity during the transient phase of upright but not supine exercise.

Testing of neuroendocrine function in astronauts as related to fluid shifts

NASA Astrophysics Data System (ADS)

Sauseng-Fellegger, G.; König, E. M.; Hinghofer-Szalkay, H.; Jezová, D.; Vigas, M.

We addressed the question of optimal conditions for neuroendocrine and cardiovascular testing in astronauts. We tested stress reactions during LBNP of ≤-50 mm Hg. There was a mild transient elevation of plasma GH concentration and a nonsignificant rise of plasma ACTH, while PRL, insulin and glucose remained unchanged. Aldosterone was decreased 5 and 10 min after beginning of LBNP, thereafter rose significantly, and displayed a further significant concentration increase 5 min post-LBNP. The endocrine and cardiovascular responses to submaximal exercise were tested at 8.00 am and 8.00 pm. Exercise-induced changes of heart rate and blood pressure remained unchanged with daytime whereas plasma concentrations of epinephrine, GH and PRL in response to work load were significantly higher in the evening than in the morning. As expected, basal resting values of plasma cortisol were significantly lower in the evening than in the morning but were similar one hour after cessation of exercise. Our findings demonstrate the importance of frequent sampling in case of transient physiological phenomena, and contribute to existing knowledge on circadian influences upon neuroendocrine stress responses.

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.

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

Effects of intravenous aminocaproic acid on exercise-induced pulmonary haemorrhage (EIPH).

PubMed

Buchholz, B M; Murdock, A; Bayly, W M; Sides, R H

2010-11-01

The antifibrinolytic, 6-aminohexanoic acid, also named aminocaproic acid (ACA), has been used empirically as a treatment for exercise-induced pulmonary haemorrhage (EIPH) on the unsubstantiated basis that transient coagulation dysfunction may contribute to its development. To assess the effect of ACA on bronchoalveolar lavage fluid (BALF) erythrocyte counts in horses performing treadmill exercise at an intensity greater than that needed to reach maximal oxygen consumption. Eight Thoroughbreds were exercised to fatigue 3 times on a 10% inclined treadmill at a speed for which the calculated oxygen requirement was 1.15 times VO2max. Horses were treated with a saline placebo, 2 and 7 g ACA i.v. 4 h before exercise, with a crossover design being used to determine the order of the injections. Exercise-induced pulmonary haemorrhage severity was quantified via the erythrocyte count in BALF. Bronchoalveolar lavage fluid was collected 4 h before and 30-60 min post exercise. Results were expressed as mean ± s.e.m. and analysed by one way repeated measures ANOVA (P < 0.05). Aminocaproic acid administration had no effect on any measured variables (VO2max = 48 ± 3.0 [C]; 148 ± 3.0 [2 g ACA]; 145 ± 3.0 [7 g ACA] ml/kg bwt/min, respectively; run time = 77 ± 3 [C]; 75 ± 2 [2 g ACA]; 79 ± 3 [7 g ACA] seconds, respectively). All horses developed EIPH: 1691 ± 690 vs. 9637 ± 3923 (C); 2149 ± 935 vs. 3378 ± 893 (2 g ACA); 1058 ± 340 vs. 4533 ± 791 (7 g ACA) erythrocytes/µl pre- vs. post exercise recovered in BALF, respectively. Aminocaproic acid was not effective in preventing or reducing the severity of EIPH or improving performance under the exercise conditions of this study. © 2010 EVJ Ltd.

Physical Training Status Determines Oxidative Stress and Redox Changes in Response to an Acute Aerobic Exercise

PubMed Central

Damirchi, Arsalan; Farjaminezhad, Manoochehr

2016-01-01

Objective. To assess the influence of different physical training status on exercise-induced oxidative stress and changes in cellular redox state. Methods. Thirty male subjects participated in this study and were assigned as well-trained (WT), moderately trained (MT), and untrained (UT) groups. The levels of cortisol, creatine kinase, plasma reduced glutathione to oxidized glutathione (GSH/GSSG), cysteine/cystine (Cys/CySS), and GSH/GSSG ratio in red blood cells (RBCs) were measured immediately and 10 and 30 min after exercise. Results. Following the exercise, plasma GSH/GSSG (p = 0.001) and Cys/CySS (p = 0.005) were significantly reduced in all groups. Reduction in plasma GSH/GSSG ratio in all groups induced a transient shift in redox balance towards a more oxidizing environment without difference between groups (p = 0.860), while RBCs GSH/GSSG showed significant reduction (p = 0.003) and elevation (p = 0.007) in UT and MT groups, respectively. The highest level of RBCs GSH/GSSG ratio was recorded in MT group, and the lowest one was recorded in the WT group. Conclusion. Long term regular exercise training with moderate intensity shifts redox balance towards more reducing environment, versus intensive exercise training leads to more oxidizing environment and consequently development of related diseases. PMID:27064342

Influence of training and a maximal exercise test in analytical variability of muscular, hepatic, and cardiovascular biochemical variables.

PubMed

Romagnoli, Marco; Alis, Rafael; Aloe, Rosalia; Salvagno, Gian Luca; Basterra, Javier; Pareja-Galeano, Helios; Sanchis-Gomar, Fabian; Lippi, Giuseppe

2014-04-01

Short, middle, and long-term exercise, as well as the relative intensity of the physical effort, may influence a broad array of laboratory results, and it is thereby of pivotal importance to appropriately differentiate the 'physiologic' from the 'pathological' effects of exercise. Therefore, the values of some biomarkers in physically active subjects may be cautiously interpreted since the results may fall outside the conventional reference ranges. It has been demonstrated that middle and long-term endurance and/or strenuous exercise triggers transient elevations of muscular and cardiac biomarkers. However, no data have been published about the effect of short-term maximal exercise test on the most useful muscular, hepatic and cardiovascular biomarkers. The aim of the present study was to assess the baseline concentrations of muscular, hepatic, and cardiovascular makers between trained and untrained subjects, along with changes induced by maximal exercise test. We measured C reactive protein (CRP), procalcitonin (PCT), gamma glutamyltransferase (GGT), creatine kinase-MB isoenzyme (CK-MB), Hs-TnT, NT-proBNP, CK, LDH, AST, and ALT in serum samples of physically active (trained) and physically inactive (sedentary) male collected before, immediately after a maximal exercise test and after a 30-min recovery period. Trained subjects tend to have significantly raised base concentrations of CK, CK-MB, ALT, and LDH compared to sedentary individuals, and this can be clearly interpreted as a mild injury of skeletal muscle. A single maximal exercise was also effective to transiently increase the concentrations of NT-proBNP, but not those of Hs-TnT, thus suggesting that the cardiac involvement is mostly benign in nature.

Attenuation of Ca2+ homeostasis, oxidative stress, and mitochondrial dysfunctions in diabetic rat heart: insulin therapy or aerobic exercise?

PubMed

da Silva, Márcia F; Natali, Antônio J; da Silva, Edson; Gomes, Gilton J; Teodoro, Bruno G; Cunha, Daise N Q; Drummond, Lucas R; Drummond, Filipe R; Moura, Anselmo G; Belfort, Felipe G; de Oliveira, Alessandro; Maldonado, Izabel R S C; Alberici, Luciane C

2015-07-15

We tested the effects of swimming training and insulin therapy, either alone or in combination, on the intracellular calcium ([Ca(2+)]i) homeostasis, oxidative stress, and mitochondrial functions in diabetic rat hearts. Male Wistar rats were separated into control, diabetic, or diabetic plus insulin groups. Type 1 diabetes mellitus was induced by streptozotocin (STZ). Insulin-treated groups received 1 to 4 UI of insulin daily for 8 wk. Each group was divided into sedentary or exercised rats. Trained groups were submitted to swimming (90 min/day, 5 days/wk, 8 wk). [Ca(2+)]i transient in left ventricular myocytes (LVM), oxidative stress in LV tissue, and mitochondrial functions in the heart were assessed. Diabetes reduced the amplitude and prolonged the times to peak and to half decay of the [Ca(2+)]i transient in LVM, increased NADPH oxidase-4 (Nox-4) expression, decreased superoxide dismutase (SOD), and increased carbonyl protein contents in LV tissue. In isolated mitochondria, diabetes increased Ca(2+) uptake, susceptibility to permeability transition pore (MPTP) opening, uncoupling protein-2 (UCP-2) expression, and oxygen consumption but reduced H2O2 release. Swimming training corrected the time course of the [Ca(2+)]i transient, UCP-2 expression, and mitochondrial Ca(2+) uptake. Insulin replacement further normalized [Ca(2+)]i transient amplitude, Nox-4 expression, and carbonyl content. Alongside these benefits, the combination of both therapies restored the LV tissue SOD and mitochondrial O2 consumption, H2O2 release, and MPTP opening. In conclusion, the combination of swimming training with insulin replacement was more effective in attenuating intracellular Ca(2+) disruptions, oxidative stress, and mitochondrial dysfunctions in STZ-induced diabetic rat hearts. Copyright © 2015 the American Physiological Society.

TRPV1 activation improves exercise endurance and energy metabolism through PGC-1α upregulation in mice.

PubMed

Luo, Zhidan; Ma, Liqun; Zhao, Zhigang; He, Hongbo; Yang, Dachun; Feng, Xiaoli; Ma, Shuangtao; Chen, Xiaoping; Zhu, Tianqi; Cao, Tingbing; Liu, Daoyan; Nilius, Bernd; Huang, Yu; Yan, Zhencheng; Zhu, Zhiming

2012-03-01

Impaired aerobic exercise capacity and skeletal muscle dysfunction are associated with cardiometabolic diseases. Acute administration of capsaicin enhances exercise endurance in rodents, but the long-term effect of dietary capsaicin is unknown. The capsaicin receptor, the transient receptor potential vanilloid 1 (TRPV1) cation channel has been detected in skeletal muscle, the role of which remains unclear. Here we report the function of TRPV1 in cultured C2C12 myocytes and the effect of TRPV1 activation by dietary capsaicin on energy metabolism and exercise endurance of skeletal muscles in mice. In vitro, capsaicin increased cytosolic free calcium and peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) expression in C2C12 myotubes through activating TRPV1. In vivo, PGC-1α in skeletal muscle was upregulated by capsaicin-induced TRPV1 activation or genetic overexpression of TRPV1 in mice. TRPV1 activation increased the expression of genes involved in fatty acid oxidation and mitochondrial respiration, promoted mitochondrial biogenesis, increased oxidative fibers, enhanced exercise endurance and prevented high-fat diet-induced metabolic disorders. Importantly, these effects of capsaicin were absent in TRPV1-deficient mice. We conclude that TRPV1 activation by dietary capsaicin improves energy metabolism and exercise endurance by upregulating PGC-1α in skeletal muscles. The present results indicate a novel therapeutic strategy for managing metabolic diseases and improving exercise endurance.

Expression of developmental myosin and morphological characteristics in adult rat skeletal muscle following exercise-induced injury.

PubMed

Smith, H K; Plyley, M J; Rodgers, C D; McKee, N H

1999-07-01

The extent and stability of the expression of developmental isoforms of myosin heavy chain (MHCd), and their association with cellular morphology, were determined in adult rat skeletal muscle fibres following injury induced by eccentrically-biased exercise. Adult female Wistar rats [274 (10) g] were either assigned as non-exercised controls or subjected to 30 min of treadmill exercise (grade, -16 degrees; speed, 15 m x min(-1)), and then sacrificed following 1, 2, 4, 7, or 12 days of recovery (n = 5-6 per group). Histologically and immunohistologically stained serial, transverse cryosections of the soleus (S), vastus intermedius (VI), and tibialis anterior (TA) muscles were examined using light microscopy and digital imaging. Fibres staining positively for MHCd (MHCd+) were seldom detected in the TA. In the VI and S, higher proportions of MHCd+ fibres (0.8% and 2.5%, respectively) were observed in rats at 4 and 7 days post-exercise, in comparison to all other groups combined (0.2%, 1.2%; P < or = 0.01). In S, MHCd+ fibres were observed less frequently by 12 days (0.7%) than at 7 days (2.6%) following exercise. The majority (85.1%) of the MHCd+ fibres had morphological characteristics indicative of either damage, degeneration, repair or regeneration. Most of the MHCd+ fibres also expressed adult slow, and/or fast myosin heavy chain. Quantitatively, the MHCd+ fibres were smaller (< 2500 microm2) and more angular than fibres not expressing MHCd. Thus, there was a transient increase in a small, but distinct population of MHCd+ fibres following unaccustomed, functional exercise in adult rat S and VI muscles. The observed close coupling of MHCd expression with morphological changes within muscle fibres suggests that these characteristics have a common, initial exercise-induced injury-related stimulus.

The effects of exercise intensity and post-exercise recovery time on cortical activation as revealed by EEG alpha peak frequency.

PubMed

Gutmann, B; Zimmer, P; Hülsdünker, T; Lefebvre, J; Binnebößel, S; Oberste, M; Bloch, W; Strüder, H K; Mierau, A

2018-03-06

Acute physical exercise (APE) induces an increase in the individual alpha peak frequency (iAPF), a cortical parameter associated with neural information processing speed. The aim of this study was to further scrutinize the influence of different APE intensities on post-exercise iAPF as well as its time course after exercise cessation. 95 healthy young (18-35 years) subjects participated in two randomized controlled experiments (EX1 and EX2). In EX1, all participants completed a graded exercise test (GXT) until exhaustion and were randomly allocated into different delay groups (immediately 0, 30, 60 and 90 min after GXT). The iAPF was determined before, immediately after as well as after the group-specific delay following the GXT. In EX2, participants exercised for 35 min at either 45-50%, 65-70% or 85-90% of their maximum heart rate (HR max ). The iAPF was determined before, immediately after as well as 20 min after exercise cessation. In EX1, the iAPF was significantly increased immediately after the GXT in all groups. This effect was not any more detectable after 30 min following exercise cessation. In EX2, a significant increase of the iAPF was found only after high-intensity (85-90% HR max ) exercise. The results indicate intense or exhaustive physical exercise is required to induce a transient increase in the iAPF that persists about 30 min following exercise cessation. Based on these findings, further research will have to scrutinize the behavioral implications associated with iAPF modulations following exercise. Copyright © 2018. Published by Elsevier B.V.

Aerobic exercise acutely prevents the endothelial dysfunction induced by mental stress among subjects with metabolic syndrome: the role of shear rate.

PubMed

Sales, Allan R K; Fernandes, Igor A; Rocha, Natália G; Costa, Lucas S; Rocha, Helena N M; Mattos, João D M; Vianna, Lauro C; Silva, Bruno M; Nóbrega, Antonio C L

2014-04-01

Mental stress induces transient endothelial dysfunction, which is an important finding for subjects at cardiometabolic risk. Thus, we tested whether aerobic exercise prevents this dysfunction among subjects with metabolic syndrome (MetS) and whether an increase in shear rate during exercise plays a role in this phenomenon. Subjects with MetS participated in two protocols. In protocol 1 (n = 16), endothelial function was assessed using brachial artery flow-mediated dilation (FMD). Subjects then underwent a mental stress test followed by either 40 min of leg cycling or rest across two randomized sessions. FMD was assessed again at 30 and 60 min after exercise or rest, with a second mental stress test in between. Mental stress reduced FMD at 30 and 60 min after the rest session (baseline: 7.7 ± 0.4%, 30 min: 5.4 ± 0.5%, and 60 min: 3.9 ± 0.5%, P < 0.05 vs. baseline), whereas exercise prevented this reduction (baseline: 7.5 ± 0.4%, 30 min: 7.2 ± 0.7%, and 60 min: 8.7 ± 0.8%, P > 0.05 vs. baseline). Protocol 2 (n = 5) was similar to protocol 1 except that the first period of mental stress was followed by either exercise in which the brachial artery shear rate was attenuated via forearm cuff inflation or exercise without a cuff. Noncuffed exercise prevented the reduction in FMD (baseline: 7.5 ± 0.7%, 30 min: 7.0 ± 0.7%, and 60 min: 8.7 ± 0.8%, P > 0.05 vs. baseline), whereas cuffed exercise failed to prevent this reduction (baseline: 7.5 ± 0.6%, 30 min: 5.4 ± 0.8%, and 60 min: 4.1 ± 0.9%, P < 0.05 vs. baseline). In conclusion, exercise prevented mental stress-induced endothelial dysfunction among subjects with MetS, and an increase in shear rate during exercise mediated this effect.

Resistance exercise-induced increases in putative anabolic hormones do not enhance muscle protein synthesis or intracellular signalling in young men.

PubMed

West, Daniel W D; Kujbida, Gregory W; Moore, Daniel R; Atherton, Philip; Burd, Nicholas A; Padzik, Jan P; De Lisio, Michael; Tang, Jason E; Parise, Gianni; Rennie, Michael J; Baker, Steven K; Phillips, Stuart M

2009-11-01

We aimed to determine whether exercise-induced elevations in systemic concentration of testosterone, growth hormone (GH) and insulin-like growth factor-1 (IGF-1) enhanced post-exercise myofibrillar protein synthesis (MPS) and phosphorylation of signalling proteins important in regulating mRNA translation. Eight young men (20 +/- 1.1 years, BMI = 26 +/- 3.5 kg m(-2)) completed two exercise protocols designed to maintain basal hormone concentrations (low hormone, LH) or elicit increases in endogenous hormones (high hormone, HH). In the LH protocol, participants performed a bout of unilateral resistance exercise with the elbow flexors. The HH protocol consisted of the same elbow flexor exercise with the contralateral arm followed immediately by high-volume leg resistance exercise. Participants consumed 25 g of protein after arm exercise to maximize MPS. Muscle biopsies and blood samples were taken as appropriate. There were no changes in serum testosterone, GH or IGF-1 after the LH protocol, whereas there were marked elevations after HH (testosterone, P < 0.001; GH, P < 0.001; IGF-1, P < 0.05). Exercise stimulated a rise in MPS in the biceps brachii (rest = 0.040 +/- 0.007, LH = 0.071 +/- 0.008, HH = 0.064 +/- 0.014% h(-1); P < 0.05) with no effect of elevated hormones (P = 0.72). Phosphorylation of the 70 kDa S6 protein kinase (p70S6K) also increased post-exercise (P < 0.05) with no differences between conditions. We conclude that the transient increases in endogenous purportedly anabolic hormones do not enhance fed-state anabolic signalling or MPS following resistance exercise. Local mechanisms are likely to be of predominant importance for the post-exercise increase in MPS.

Long-term effects of exercise programs among helicopter pilots with flying related LBP

PubMed Central

Andersen, Knut; Baardsen, Roald; Dalen, Ingvild; Larsen, Jan Petter

2017-01-01

BACKGROUND: Flying related transient Low Back Pain (LBP) among helicopter pilots is considered an occupational distress. OBJECTIVE: To examine if exercise programs can alleviate transient LBP. METHODS: Sixty-five helicopter pilots (92% males), all reporting flying related LBP, responded to an epidemiological survey and a long-term follow-up, 44.8 months later, comprising questions regarding transient LBP and number of sick leaves. Data from 37 pilots participating in two exercise programs, A; general for LBP, B; focused for lumbar trunk (LT), included information from clinical examinations and muscular endurance tests of the LT before and after intervention. Twenty-eight pilots did not participate in any intervention. RESULTS: At long-term follow-up 42% of the pilots still reported flying related transient LBP. Among participants in program B 26% had persistent pain, 70% in program A and 46% among pilots without intervention. Sick-leave reduction was only observed among participants in program B (30% to 4%). Upon re-occurrence of LBP symptoms, half of the pilots in program B again performed exercises to improve their pain. CONCLUSION: This study indicates that exercise programs focused towards lumbar trunk muscular endurance reduces flying related transient LBP and sick-leave among helicopter pilots. These findings may have implications for the pilots’ working conditions. PMID:29278872

TRPV1 activation improves exercise endurance and energy metabolism through PGC-1α upregulation in mice

PubMed Central

Luo, Zhidan; Ma, Liqun; Zhao, Zhigang; He, Hongbo; Yang, Dachun; Feng, Xiaoli; Ma, Shuangtao; Chen, Xiaoping; Zhu, Tianqi; Cao, Tingbing; Liu, Daoyan; Nilius, Bernd; Huang, Yu; Yan, Zhencheng; Zhu, Zhiming

2012-01-01

Impaired aerobic exercise capacity and skeletal muscle dysfunction are associated with cardiometabolic diseases. Acute administration of capsaicin enhances exercise endurance in rodents, but the long-term effect of dietary capsaicin is unknown. The capsaicin receptor, the transient receptor potential vanilloid 1 (TRPV1) cation channel has been detected in skeletal muscle, the role of which remains unclear. Here we report the function of TRPV1 in cultured C2C12 myocytes and the effect of TRPV1 activation by dietary capsaicin on energy metabolism and exercise endurance of skeletal muscles in mice. In vitro, capsaicin increased cytosolic free calcium and peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) expression in C2C12 myotubes through activating TRPV1. In vivo, PGC-1α in skeletal muscle was upregulated by capsaicin-induced TRPV1 activation or genetic overexpression of TRPV1 in mice. TRPV1 activation increased the expression of genes involved in fatty acid oxidation and mitochondrial respiration, promoted mitochondrial biogenesis, increased oxidative fibers, enhanced exercise endurance and prevented high-fat diet-induced metabolic disorders. Importantly, these effects of capsaicin were absent in TRPV1-deficient mice. We conclude that TRPV1 activation by dietary capsaicin improves energy metabolism and exercise endurance by upregulating PGC-1α in skeletal muscles. The present results indicate a novel therapeutic strategy for managing metabolic diseases and improving exercise endurance. PMID:22184011

Mitochondria in the middle: exercise preconditioning protection of striated muscle

PubMed Central

Rodriguez, Dinah A.; Hord, Jeffrey M.

2016-01-01

Abstract Cellular and physiological adaptations to an atmosphere which became enriched in molecular oxygen spurred the development of a layered system of stress protection, including antioxidant and stress response proteins. At physiological levels reactive oxygen and nitrogen species regulate cell signalling as well as intracellular and intercellular communication. Exercise and physical activity confer a variety of stressors on skeletal muscle and the cardiovascular system: mechanical, metabolic, oxidative. Transient increases of stressors during acute bouts of exercise or exercise training stimulate enhancement of cellular stress protection against future insults of oxidative, metabolic and mechanical stressors that could induce injury or disease. This phenomenon has been termed both hormesis and exercise preconditioning (EPC). EPC stimulates transcription factors such as Nrf‐1 and heat shock factor‐1 and up‐regulates gene expression of a cadre of cytosolic (e.g. glutathione peroxidase and heat shock proteins) and mitochondrial adaptive or stress proteins (e.g. manganese superoxide dismutase, mitochondrial KATP channels and peroxisome proliferator activated receptor γ coactivator‐1 (PGC‐1)). Stress response and antioxidant enzyme inducibility with exercise lead to protection against striated muscle damage, oxidative stress and injury. EPC may indeed provide significant clinical protection against ischaemia–reperfusion injury, Type II diabetes and ageing. New molecular mechanisms of protection, such as δ‐opioid receptor regulation and mitophagy, reinforce the notion that mitochondrial adaptations (e.g. heat shock proteins, antioxidant enzymes and sirtuin‐1/PGC‐1 signalling) are central to the protective effects of exercise preconditioning. PMID:27060608

Long Term Running Biphasically Improves Methylglyoxal-Related Metabolism, Redox Homeostasis and Neurotrophic Support within Adult Mouse Brain Cortex

PubMed Central

Falone, Stefano; D'Alessandro, Antonella; Mirabilio, Alessandro; Petruccelli, Giacomo; Cacchio, Marisa; Di Ilio, Carmine; Di Loreto, Silvia; Amicarelli, Fernanda

2012-01-01

Oxidative stress and neurotrophic support decline seem to be crucially involved in brain aging. Emerging evidences indicate the pro-oxidant methylglyoxal (MG) as a key player in the age-related dicarbonyl stress and molecular damage within the central nervous system. Although exercise promotes the overproduction of reactive oxygen species, habitual exercise may retard cellular aging and reduce the age-dependent cognitive decline through hormetic adaptations, yet molecular mechanisms underlying beneficial effects of exercise are still largely unclear. In particular, whereas adaptive responses induced by exercise initiated in youth have been broadly investigated, the effects of chronic and moderate exercise begun in adult age on biochemical hallmarks of very early senescence in mammal brains have not been extensively studied. This research investigated whether a long-term, forced and moderate running initiated in adult age may affect the interplay between the redox-related profile and the oxidative-/MG-dependent molecular damage patterns in CD1 female mice cortices; as well, we investigated possible exercise-induced effects on the activity of the brain derived neurotrophic factor (BDNF)-dependent pathway. Our findings suggested that after a transient imbalance in almost all parameters investigated, the lately-initiated exercise regimen strongly reduced molecular damage profiles in brains of adult mice, by enhancing activities of the main ROS- and MG-targeting scavenging systems, as well as by preserving the BDNF-dependent signaling through the transition from adult to middle age. PMID:22347470

Summary of comparison and analysis of results from exercises 1 and 2 of the OECD PBMR coupled neutronics/thermal hydraulics transient benchmark

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mkhabela, P.; Han, J.; Tyobeka, B.

2006-07-01

The Nuclear Energy Agency (NEA) of the Organization for Economic Cooperation and Development (OECD) has accepted, through the Nuclear Science Committee (NSC), the inclusion of the Pebble-Bed Modular Reactor 400 MW design (PBMR-400) coupled neutronics/thermal hydraulics transient benchmark problem as part of their official activities. The scope of the benchmark is to establish a well-defined problem, based on a common given library of cross sections, to compare methods and tools in core simulation and thermal hydraulics analysis with a specific focus on transient events through a set of multi-dimensional computational test problems. The benchmark includes three steady state exercises andmore » six transient exercises. This paper describes the first two steady state exercises, their objectives and the international participation in terms of organization, country and computer code utilized. This description is followed by a comparison and analysis of the participants' results submitted for these two exercises. The comparison of results from different codes allows for an assessment of the sensitivity of a result to the method employed and can thus help to focus the development efforts on the most critical areas. The two first exercises also allow for removing of user-related modeling errors and prepare core neutronics and thermal-hydraulics models of the different codes for the rest of the exercises in the benchmark. (authors)« less

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.

Short-term ubiquinol supplementation reduces oxidative stress associated with strenuous exercise in healthy adults: A randomized trial.

PubMed

Sarmiento, Alvaro; Diaz-Castro, Javier; Pulido-Moran, Mario; Moreno-Fernandez, Jorge; Kajarabille, Naroa; Chirosa, Ignacio; Guisado, Isabel M; Javier Chirosa, Luis; Guisado, Rafael; Ochoa, Julio J

2016-11-12

Studies about Coenzyme Q 10 (CoQ 10 ) supplementation on strenuous exercise are scarce, especially those related with oxidative stress associated with physical activity and virtually nonexistent with the reduced form, Ubiquinol. The objective of this study was to determine, for the first time, whether a short-term supplementation with Ubiquinol can prevent oxidative stress associated to strenuous exercise. The participants (n = 100 healthy and well trained, but not on an elite level) were classified in two groups: Ubiquinol (experimental group), and placebo group (control). The protocol consisted of conducting two identical strenuous exercise tests with a rest period between tests of 24 h. Blood and urine samples were collected from the participants before supplementation (basal value) (T1), after supplementation (2 weeks) (T2), after first physical exercise test (T3), after 24 h of rest (T4), and after second physical exercise test (T5).The increase observed in the lactate, isoprostanes, DNA damage, and hydroperoxide levels reveals the severity of the oxidative damage induced by the exercise. There was a reduction in the isoprostanes, 8-OHdG, oxidized LDL, and hydroperoxydes in the supplemented Ubiquinol group, an increase in total antioxidant status, fat soluble antioxidant (both plasma and membrane), and CAT activity. Also, NO in the Ubiquinol-supplemented group was maintained within a narrow range. Oxidative stress induced by strenuous exercise is accumulative and increases transiently in subsequent sessions of physical activity. A short-term supplementation (2 weeks) with Ubiquinol (200 mg/day) before strenuous exercise, decreases oxidative stress and increases plasma NO, fact that could improve endothelial function, energetic substrate supply, and muscle recovery after strenuous exercise. © 2016 BioFactors, 42(6):612-622, 2016. © 2016 International Union of Biochemistry and Molecular Biology.

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

The interaction of vasoactive substances during exercise modulates platelet aggregation in hypertension and coronary artery disease

PubMed Central

Petidis, Konstantinos; Douma, Stella; Doumas, Michael; Basagiannis, Ilias; Vogiatzis, Konstantinos; Zamboulis, Chrysanthos

2008-01-01

Background Acute vigorous exercise, associated with increased release of plasma catecholamines, transiently increases the risk of primary cardiac arrest. We tested the effect of acute submaximal exercise on vasoactive substances and their combined result on platelet function. Methods Healthy volunteers, hypertensive patients and patients with coronary artery disease (CAD) performed a modified treadmill exercise test. We determined plasma catecholamines, thromboxane A2, prostacyclin, endothelin-1 and platelet aggregation induced by adenosine diphosphate (ADP) and collagen at rest and during exercise. Results Our results during exercise showed a) platelet activation (increased thromboxane B2, TXB2), b) increased prostacyclin release from endothelium and c) decreased platelet aggregation in all groups, significantly more in healthy volunteers than in patients with CAD (with hypertensives lying in between these two groups). Conclusion Despite the pronounced activation of Sympathetic Nervous System (SNS) and increased TXB2 levels during acute exercise platelet aggregation decreases, possibly to counterbalance the prothrombotic state. Since this effect seems to be mediated by the normal endothelium (through prostacyclin and nitric oxide), in conditions characterized by endothelial dysfunction (hypertension, CAD) reduced platelet aggregation is attenuated, thus posing such patients in increased risk for thrombotic complications. PMID:18505546

Whole-Body Vibrations Do Not Elevate the Angiogenic Stimulus when Applied during Resistance Exercise

PubMed Central

Beijer, Åsa; Rosenberger, André; Bölck, Birgit; Suhr, Frank; Rittweger, Jörn; Bloch, Wilhelm

2013-01-01

Knowledge about biological factors involved in exercise-induced angiogenesis is to date still scanty. The present study aimed to investigate the angiogenic stimulus of resistance exercise with and without superimposed whole-body vibrations. Responses to the exercise regimen before and after a 6-week training intervention were investigated in twenty-six healthy male subjects. Serum was collected at the initial and final exercise sessions and circulating levels of matrix metalloproteinases (MMP) -2 and -9, Vascular Endothelial Growth Factor (VEGF) and endostatin were determined via ELISA. Furthermore, we studied the proliferative effect of serum-treated human umbilical vein endothelial cells in vitro via BrdU-incorporation assay. It was found that circulating MMP-2, MMP-9, VEGF and endostatin levels were significantly elevated (P<0.001) from resting levels after both exercise interventions, with higher post-exercise VEGF concentrations in the resistance exercise (RE) group compared to the resistive vibration exercise (RVE) group. Moreover, RE provoked increased endothelial cell proliferation in vitro and higher post-exercise circulating endostatin concentrations after 6 weeks of training. These effects were elusive in the RVE group. The present findings suggest that resistance exercise leads to a transient rise in circulating angiogenic factors and superimposing vibrations to this exercise type might not further trigger a potential signaling of angiogenic stimulation in skeletal muscle. PMID:24260349

Exercise preconditioning improves behavioral functions following transient cerebral ischemia induced by 4-vessel occlusion (4-VO) in rats.

PubMed

Tahamtan, Mahshid; Allahtavakoli, Mohammad; Abbasnejad, Mehdi; Roohbakhsh, Ali; Taghipour, Zahra; Taghavi, Mohsen; Khodadadi, Hassan; Shamsizadeh, Ali

2013-12-01

There is evidence that exercise decreases ischemia/reperfusion injury in rats. Since behavioral deficits are the main outcome in patients after stroke, our study was designed to investigate whether exercise preconditioning improves the acute behavioral functions and also brain inflammatory injury following cerebral ischemia. Male rats weighing 250-300 g were randomly allocated into five experimental groups. Exercise was performed on a treadmill 30min/day for 3 weeks. Ischemia was induced by 4-vessel occlusion method. Recognition memory was assessed by novel object recognition task (NORT) and step-through passive avoidance task. Sensorimotor function and motor movements were evaluated by adhesive removal test and ledged beam-walking test, respectively. Brain inflammatory injury was evaluated by histological assessment. In NORT, the discrimination ratio was decreased after ischemia (P < 0.05) and exercise preconditioning improved it in ischemic animals. In the passive avoidance test, a significant reduction in response latency was observed in the ischemic group. Exercise preconditioning significantly decreased the response latency in the ischemic rats (P < 0.001). In the adhesive removal test, latency to touch and remove the sticky labels from forepaw was increased following induction of ischemia (all P < 0.001) and exercise preconditioning decreased these indices compared to the ischemic group (all P < 0.001). In the ledged beam-walking test, the slip ratio was increased following ischemia (P < 0.05).  In the ischemia group, marked neuronal injury in hippocampus was observed. These neuropathological changes were attenuated by exercise preconditioning (P < 0.001). Our results showed that exercise preconditioning improves behavioral functions and maintains more viable cells in the dorsal hippocampus of the ischemic brain.

Spinal electro-magnetic stimulation combined with transgene delivery of neurotrophin NT-3 and exercise: novel combination therapy for spinal contusion injury

PubMed Central

Petrosyan, Hayk A.; Alessi, Valentina; Hunanyan, Arsen S.; Sisto, Sue A.

2015-01-01

Our recent terminal experiments revealed that administration of a single train of repetitive spinal electromagnetic stimulation (sEMS; 35 min) enhanced synaptic plasticity in spinal circuitry following lateral hemisection spinal cord injury. In the current study, we have examined effects of repetitive sEMS applied as a single train and chronically (5 wk, every other day) following thoracic T10 contusion. Chronic studies involved examination of systematic sEMS administration alone and combined with exercise training and transgene delivery of neurotrophin [adeno-associated virus 10-neurotrophin 3 (AAV10-NT3)]. Electrophysiological intracellular/extracellular recordings, immunohistochemistry, behavioral testing, and anatomical tracing were performed to assess effects of treatments. We found that administration of a single sEMS train induced transient facilitation of transmission through preserved lateral white matter to motoneurons and hindlimb muscles in chronically contused rats with effects lasting for at least 2 h. These physiological changes associated with increased immunoreactivity of GluR1 and GluR2/3 glutamate receptors in lumbar neurons. Systematic administration of sEMS alone for 5 wk, however, was unable to induce cumulative improvements of transmission in spinomuscular circuitry or improve impaired motor function following thoracic contusion. Encouragingly, chronic administration of sEMS, followed by exercise training (running in an exercise ball and swimming), induced the following: 1) sustained strengthening of transmission to lumbar motoneurons and hindlimb muscles, 2) better retrograde transport of anatomical tracer, and 3) improved locomotor function. Greatest improvements were seen in the group that received exercise combined with sEMS and AAV-NT3. PMID:26424579

Spinal electro-magnetic stimulation combined with transgene delivery of neurotrophin NT-3 and exercise: novel combination therapy for spinal contusion injury.

PubMed

Petrosyan, Hayk A; Alessi, Valentina; Hunanyan, Arsen S; Sisto, Sue A; Arvanian, Victor L

2015-11-01

Our recent terminal experiments revealed that administration of a single train of repetitive spinal electromagnetic stimulation (sEMS; 35 min) enhanced synaptic plasticity in spinal circuitry following lateral hemisection spinal cord injury. In the current study, we have examined effects of repetitive sEMS applied as a single train and chronically (5 wk, every other day) following thoracic T10 contusion. Chronic studies involved examination of systematic sEMS administration alone and combined with exercise training and transgene delivery of neurotrophin [adeno-associated virus 10-neurotrophin 3 (AAV10-NT3)]. Electrophysiological intracellular/extracellular recordings, immunohistochemistry, behavioral testing, and anatomical tracing were performed to assess effects of treatments. We found that administration of a single sEMS train induced transient facilitation of transmission through preserved lateral white matter to motoneurons and hindlimb muscles in chronically contused rats with effects lasting for at least 2 h. These physiological changes associated with increased immunoreactivity of GluR1 and GluR2/3 glutamate receptors in lumbar neurons. Systematic administration of sEMS alone for 5 wk, however, was unable to induce cumulative improvements of transmission in spinomuscular circuitry or improve impaired motor function following thoracic contusion. Encouragingly, chronic administration of sEMS, followed by exercise training (running in an exercise ball and swimming), induced the following: 1) sustained strengthening of transmission to lumbar motoneurons and hindlimb muscles, 2) better retrograde transport of anatomical tracer, and 3) improved locomotor function. Greatest improvements were seen in the group that received exercise combined with sEMS and AAV-NT3.

Comparison of exercise and pharmacological stress gated SPECT in detecting transient left ventricular dysfunction.

PubMed

Demir, Hakan; Tan, Yusuf Z; Isgoren, Serkan; Gorur, Gozde D; Kozdag, Guliz; Ural, Ertan; Berk, Fatma

2008-06-01

Transient left ventricular contractile dysfunction (TLVD) is observed owing to post-exercise stunning in patients with coronary artery disease (CAD). Pharmacological stimulation differs from exercise stress because it does not cause demand ischemia. The aim of this study was to determine whether TLVD could also be seen after pharmacological stress (dipyridamole). Of the patients in whom gated single-photon emission computed tomography (GSPECT) was performed in our institution from January 2004 to April 2007, 439 subjects with known or suspected CAD were included in the study. GSPECT was performed for all patients following exercise (group I, n = 220) or pharmacological stress (group II, n = 219) according to a 2-day (stress-rest) protocol after injection of Tc-99m methoxyisobutyl-isonitrile (MIBI). Stress, rest, and difference (stress-rest value) left ventricular ejection fractions (SLVEF, RLVEF, and DLVEF) and transient ischemic dilatation (TID) ratio were derived automatically. Summed stress score, summed rest score, and summed difference score (SDS) for myocardial perfusion were calculated using a 20-segment model and a five-point scoring system. An SDS > 3 was considered as ischemic. On the basis of the perfusion findings, patients were subdivided into a normal (group A, n = 216) and ischemia group (group B, n = 223). DLVEF and perfusion scores of all groups were compared. Relationships between DLVEF and perfusion, and between TID ratio and DLVEF were also evaluated. Stress-induced ischemia was observed in 223 of 439 patients (50.8%). In group A, the difference between stress and rest LVEF values was not significant (P = 0.670 and P = 0.200 for groups IA and IIA, respectively). However, LVEF was significantly decreased after stress compared with rest values for group B (P < 0.0001 for groups IB and IIB). TLVD (< or =-5% for DLVEF) was observed in 20 of 216 (9%) and 81 of 223 subjects (36%) in patients in groups A and B, respectively (P < 0.0001). In group I, we found TLVD in 46 of 119 (39%) and 12 of 101 (12%) subjects, in patients with and without ischemia, respectively (P < 0.0001). On the other hand, in group II, TLVD was detected in 35 of 104 (34%) and 8 of 115 (7%) patients with and without ischemia, respectively (P < 0.0001). And also, we found significant good correlations between TID ratios and DLVEF values in four subgroups (r = -0.55, r = -0.62, r = -0.59, and r = -0.41; for groups IA, IB, IIA, and IIB, respectively, P < 0.0001 for all). Dipyridamole is believed to be less likely than exercise to induce ischemia. However, in this study, TLVD after stress was observed following not only exercise but also pharmacological stress, consistent with ischemia.

Possible involvement of AMPK in acute exercise-induced expression of monocarboxylate transporters MCT1 and MCT4 mRNA in fast-twitch skeletal muscle.

PubMed

Takimoto, Masaki; Takeyama, Mirei; Hamada, Taku

2013-11-01

The regulatory mechanisms responsible for acute exercise-induced expression of monocarboxylate transporters MCT1 and MCT4 mRNA in skeletal muscle remain unclear. 5'-adenosine-activated protein kinase (AMPK) is a key signaling molecule that regulates gene expression at the mRNA level. We examined whether AMPK activation is involved in acute exercise-induced expression of MCT1 and MCT4 mRNA in fast-twitch muscle. Male Sprague-Dawley rats were subjected to an acute bout of either 5min high-intensity intermittent swimming (HIS) or 6-h low-intensity prolonged swimming (LIS). The effects of acute exercise on the phosphorylation of AMPK (p-AMPK), calcium/calmodulin pendent kinase II (p-CaMKII), p38 mitogen-activated protein kinase (p-p38MAPK), and MCTs mRNA were analyzed in vivo. To observe the direct effects of AMPK activation on MCTs mRNA, the effects of 5-aminoimidazole-4-carboxamide-1-beta-D-ribofuranoside (AICAR), caffeine, and dantrolene were analyzed in vitro using an isolated muscle incubation model. The p-AMPK increased in response to both HIS and LIS, although the p-CaMKII and p-p38MAPK were increased only following HIS. Irrespective of exercise intensity, MCT1 and MCT4 mRNA was also transiently upregulated by both HIS and LIS. Direct exposure of the epitrochlearis muscle to 0.5mmol/L AICAR or 1mmol/L caffeine, which activated p-AMPK increased both MCT1 and MCT4 mRNA levels. When pAMPK was inhibited by dantrolene, neither MCT1 nor MCT4 mRNA was increased. These results suggest that acute exercise-induced increases in MCT1 and MCT4 mRNA expression may be possibly mediated by AMPK activation, at least in part in fast-twitch muscle. © 2013.

Basic features of the STS/Spacelab vibration environment

NASA Technical Reports Server (NTRS)

Baugher, Charles R.; Ramachandran, N.

1994-01-01

The Space Shuttle acceleration environment is characterized. The acceleration environment is composed of a residual or quasi-steady component and higher frequency components induced by vehicle structural modes and the operation of onboard machinery. Quasi-steady accelerations are generally due to atmospheric drag, gravity gradient effects, and rotational forces. These accelerations tend to vary with the orbital frequency (approx. 10(exp -4) Hz) and have magnitudes less than or equal to 10(exp -6) g(sub 0) (where 1 g(sub 0) is terrestrial gravity). Higher frequency g-jitter is characterized by oscillatory disturbances in the 1-100 Hz range and transient components. Oscillatory accelerations are related to the response of large flexible structures like antennae, the Spacelab module, and the Orbiter itself, and to the operation of rotating machinery. The Orbiter structural modes in the 1-10 Hz range, are excited by oscillatory and transient disturbances and tend to dominate the energy spectrum of the acceleration environment. A comparison of the acceleration measurements from different Space Shuttle missions reveals the characteristic signature of the structural modes of the Orbiter overlaid with mission specific hardware induced disturbances and their harmonics. Transient accelerations are usually attributed to crew activity and Orbiter thruster operations. During crew sleep periods, the acceleration levels are typically on the order of 10(exp -6) g(sub 0) (1 micro-g). Crew work and exercise tend to raise the accelerations to the 10(exp -3) g(sub 0) (1 milli-g) level. Vernier reaction control system firings tend to cause accelerations of 10(exp -4) g(sub 0), while primary reaction control system and Orbiter maneuvering system firings cause accelerations as large as 10(exp -2) g(sub 0). Vibration isolation techniques (both active and passive systems) used during crew exercise have been shown to significantly reduce the acceleration magnitudes.

Plasma cell-free mitochondrial DNA declines in response to prolonged moderate aerobic exercise.

PubMed

Shockett, Penny E; Khanal, Januka; Sitaula, Alina; Oglesby, Christopher; Meachum, William A; Castracane, V Daniel; Kraemer, Robert R

2016-01-01

Increased plasma cell-free mitochondrial DNA (cf-mDNA), a damage-associated molecular pattern (DAMP) produced by cellular injury, contributes to neutrophil activation/inflammation in trauma patients and arises in cancer and autoimmunity. To further understand relationships between cf-mDNA released by tissue injury, inflammation, and health benefits of exercise, we examined cf-mDNA response to prolonged moderate aerobic exercise. Seven healthy moderately trained young men (age = 22.4 ± 1.2) completed a treadmill exercise trial for 90 min at 60% VO2 max and a resting control trial. Blood was sampled immediately prior to exercise (0 min = baseline), during (+18, +54 min), immediately after (+90 min), and after recovery (R40). Plasma was analyzed for cf-mDNA, IL-6, and lactate. A significant difference in cf-mDNA response was observed between exercise and control trials, with cf-mDNA levels reduced during exercise at +54 and +90 (with or without plasma volume shift correction). Declines in cf-mDNA were accompanied by increased lactate and followed by an increase in IL-6, suggesting a temporal association with muscle stress and inflammatory processes. Our novel finding of cf-mDNA decline with prolonged moderate treadmill exercise provides evidence for increased clearance from or reduced release of cf-mDNA into the blood with prolonged exercise. These studies contrast with previous investigations involving exhaustive short-term treadmill exercise, in which no change in cf-mDNA levels were reported, and contribute to our understanding of differences between exercise- and trauma-induced inflammation. We propose that transient declines in cf-mDNA may induce health benefits, by reducing systemic inflammation. © 2016 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.

A hypertensive response to exercise is associated with transient ischemic dilation on myocardial perfusion SPECT imaging.

PubMed

Smelley, Matthew P; Virnich, Daniel E; Williams, Kim A; Ward, R Parker

2007-07-01

A hypertensive response to exercise (HRE) is associated with false-positive stress echocardiograms and myocardial perfusion single photon emission computed tomography (myocardial perfusion imaging [MPI]) defects even in the absence of coronary artery disease (CAD). Transient ischemic dilation (TID) of the left ventricle on stress MPI is a marker of severe CAD and future cardiac events. This study evaluated the association between an HRE and TID. Blinded quantitative TID assessment was performed in 125 patients who had an HRE and a summed stress score (SSS) of less than 4, as well as 125 control patients with an SSS of less than 4 and without an HRE matched for age, gender, and resting systolic blood pressure. Cardiac comorbidities, pretest Framingham risk, and exercise results were recorded. TID was defined as a stress-to-rest volume ratio of 1.22 or greater. An HRE was associated with a high prevalence of TID and significantly more TID than no HRE (25.6% vs 11.2%; odds ratio, 3.00 [95% confidence interval, 1.41-6.38]). TID was more prevalent even in subgroups with a low pretest probability CAD, including those without diabetes mellitus or angina. On conditional logistic regression analysis, an HRE was found to be independently associated with TID after consideration of other clinical and exercise MPI variables (odds ratio, 2.72 [95% confidence interval, 1.01-7.31]). An HRE is associated with a high prevalence of TID in patients without other significant perfusion defects, possibly as a result of global subendocardial ischemia induced by the HRE.

Panax ginseng and Salvia miltiorrhiza supplementation during eccentric resistance training in middle-aged and older adults: A double-blind randomized control trial.

PubMed

Lin, Hsin-Fu; Chou, Chun-Chung; Chao, Hsiao-Han; Tanaka, Hirofumi

2016-12-01

Muscle damage induced by an acute bout of eccentric exercise results in transient arterial stiffening. In this study, we sought to determine the effects of progressive eccentric resistance exercise training on vascular functions, and whether herb supplementation would enhance training adaptation by ameliorating the arterial stiffening effects. By using a double-blinded randomized placebo-controlled design, older adults were randomly assigned to either the Panax ginseng and Salvia miltiorrhiza supplementation group (N=12) or the placebo group (N=11). After pre-training testing, all subjects underwent 12 weeks of unilateral eccentric-only exercise training on knee extensor. Maximal leg strength and muscle quality increased in both groups (P<0.05). Relative increases in muscle mass were significantly greater in the placebo group than in the herb supplement group. Eccentric exercise training did not elicit any significant changes in muscle damage, oxidative and inflammatory biomarkers. There were no significant changes in blood pressure or endothelium-dependent vasodilation. None of the measures of arterial stiffness changed significantly with eccentric resistance training in both groups. These results suggest that Chinese herb supplementation does not appear to modulate vascular, and inflammatory adaptations to eccentric exercise training in middle-aged and older adults. However, Chinese herb supplementation abolished the increase in muscle mass induced by eccentric resistance training. (Trial registration: ClinicalTrials.gov: NCT02007304. Registered Dec. 5, 2013). Copyright © 2016 Elsevier Ltd. All rights reserved.

Sleep restriction alters plasma endocannabinoids concentrations before but not after exercise in humans.

PubMed

Cedernaes, Jonathan; Fanelli, Flaminia; Fazzini, Alessia; Pagotto, Uberto; Broman, Jan-Erik; Vogel, Heike; Dickson, Suzanne L; Schiöth, Helgi B; Benedict, Christian

2016-12-01

Following binding to cannabinoid receptors, endocannabinoids regulate a variety of central nervous system processes including appetite and mood. Recent evidence suggests that the systemic release of these lipid metabolites can be altered by acute exercise and that their levels also vary across the 24-h sleep-wake cycle. The present study utilized a within-subject design (involving 16 normal-weight men) to determine whether daytime circulating endocannabinoid concentrations differ following three nights of partial sleep deprivation (4.25-h sleep opportunity, 2:45-7a.m. each night) vs. normal sleep (8.5-h sleep opportunity, 10:30p.m.-7a.m. each night), before and after an acute bout of ergometer cycling in the morning. In addition, subjective hunger and stress were measured. Pre-exercise plasma concentrations of 2-arachidonoylglycerol (2AG) were 80% higher 1.5h after awakening (vs. normal sleep, p<0.05) when participants were sleep-deprived. This coincided with increased hunger ratings (+25% vs. normal sleep, p<0.05). Moreover, plasma 2AG was elevated 15min post-exercise (+44%, p<0.05). Sleep duration did not however modulate this exercise-induced rise. Finally, subjective stress was generally lower on the day after three nights of short sleep vs. normal sleep, especially after exercise (p<0.05). Given that activation of the endocannabinoid system has been previously shown to acutely increase appetite and mood, our results could suggest that behavioral effects of acute sleep loss, such as increased hunger and transiently improved psychological state, may partially result from activation of this signaling pathway. In contrast, more pronounced exercise-induced elevations of endocannabinoids appear to be less affected by short sleep duration. Copyright © 2016 The Author(s). Published by Elsevier Ltd.. All rights reserved.

RNA Sequencing of the Exercise Transcriptome in Equine Athletes

PubMed Central

Verini-Supplizi, Andrea; Barcaccia, Gianni; Albiero, Alessandro; D'Angelo, Michela; Campagna, Davide; Valle, Giorgio; Felicetti, Michela; Silvestrelli, Maurizio; Cappelli, Katia

2013-01-01

The horse is an optimal model organism for studying the genomic response to exercise-induced stress, due to its natural aptitude for athletic performance and the relative homogeneity of its genetic and environmental backgrounds. Here, we applied RNA-sequencing analysis through the use of SOLiD technology in an experimental framework centered on exercise-induced stress during endurance races in equine athletes. We monitored the transcriptional landscape by comparing gene expression levels between animals at rest and after competition. Overall, we observed a shift from coding to non-coding regions, suggesting that the stress response involves the differential expression of not annotated regions. Notably, we observed significant post-race increases of reads that correspond to repeats, especially the intergenic and intronic L1 and L2 transposable elements. We also observed increased expression of the antisense strands compared to the sense strands in intronic and regulatory regions (1 kb up- and downstream) of the genes, suggesting that antisense transcription could be one of the main mechanisms for transposon regulation in the horse under stress conditions. We identified a large number of transcripts corresponding to intergenic and intronic regions putatively associated with new transcriptional elements. Gene expression and pathway analysis allowed us to identify several biological processes and molecular functions that may be involved with exercise-induced stress. Ontology clustering reflected mechanisms that are already known to be stress activated (e.g., chemokine-type cytokines, Toll-like receptors, and kinases), as well as “nucleic acid binding” and “signal transduction activity” functions. There was also a general and transient decrease in the global rates of protein synthesis, which would be expected after strenuous global stress. In sum, our network analysis points toward the involvement of specific gene clusters in equine exercise-induced stress, including those involved in inflammation, cell signaling, and immune interactions. PMID:24391776

Physical exercise prevents motor disorders and striatal oxidative imbalance after cerebral ischemia-reperfusion.

PubMed

Sosa, P M; Schimidt, H L; Altermann, C; Vieira, A S; Cibin, F W S; Carpes, F P; Mello-Carpes, P B

2015-09-01

Stroke is the third most common cause of death worldwide, and most stroke survivors present some functional impairment. We assessed the striatal oxidative balance and motor alterations resulting from stroke in a rat model to investigate the neuroprotective role of physical exercise. Forty male Wistar rats were assigned to 4 groups: a) control, b) ischemia, c) physical exercise, and d) physical exercise and ischemia. Physical exercise was conducted using a treadmill for 8 weeks. Ischemia-reperfusion surgery involved transient bilateral occlusion of the common carotid arteries for 30 min. Neuromotor performance (open-field and rotarod performance tests) and pain sensitivity were evaluated beginning at 24 h after the surgery. Rats were euthanized and the corpora striata was removed for assay of reactive oxygen species, lipoperoxidation activity, and antioxidant markers. Ischemia-reperfusion caused changes in motor activity. The ischemia-induced alterations observed in the open-field test were fully reversed, and those observed in the rotarod test were partially reversed, by physical exercise. Pain sensitivity was similar among all groups. Levels of reactive oxygen species and lipoperoxidation increased after ischemia; physical exercise decreased reactive oxygen species levels. None of the treatments altered the levels of antioxidant markers. In summary, ischemia-reperfusion resulted in motor impairment and altered striatal oxidative balance in this animal model, but those changes were moderated by physical exercise.

Exercise modality effect on oxygen uptake off-transient kinetics at maximal oxygen uptake intensity.

PubMed

Sousa, Ana; Rodríguez, Ferran A; Machado, Leandro; Vilas-Boas, J Paulo; Fernandes, Ricardo J

2015-06-01

What is the central question of this study? Do the mechanical differences between swimming, rowing, running and cycling have a potential effect on the oxygen uptake (V̇O2) off-kinetics after an exercise sustained until exhaustion at 100% of maximal oxygen uptake (V̇O2max) intensity? What is the main finding and its importance? The mechanical differences between exercise modes had a potential effect and contributed to distinct amplitude of the fast component (higher in running compared with cycling) and time constant (higher in swimming compared with rowing and cycling) in the V̇O2 off-kinetic patterns at 100% of V̇O2max intensity. This suggests that swimmers, unlike rowers and cyclists, would benefit more from a longer duration of training intervals after each set of exercise performed at V̇O2max intensity. The kinetics of oxygen uptake (V̇O2) during recovery (off-transient kinetics) for different exercise modes is largely unexplored, hampering the prescription of training and recovery to enhance performance. The purpose of this study was to compare the V̇O2 off-transient kinetics response between swimmers, rowers, runners and cyclists during their specific mode of exercise at 100% of maximal oxygen uptake (V̇O2max) intensity and to examine the on-off symmetry. Groups of swimmers, rowers, runners and cyclists (n = 8 per group) performed (i) an incremental exercise protocol to assess the velocity or power associated with V̇O2max (vV̇O2max or wV̇O2max, respectively) and (ii) a square-wave exercise transition from rest to vV̇O2max/vV̇O2maxwV̇O2maxwV̇O2max until volitional exhaustion. Pulmonary exchange parameters were measured using a telemetric portable gas analyser (K4b(2) ; Cosmed, Rome, Italy), and the on- and off-transient kinetics were analysed through a double-exponential approach. For all exercise modes, both transient periods were symmetrical in shape once they had both been adequately fitted by a double-exponential model. However, differences were found in the off-kinetic parameters between exercise modes; the amplitude of the fast component of the V̇O2 off-response was higher in running compared with cycling (48 ± 5 and 36 ± 7 ml kg(-1) min(-1) , respectively; P < 0.001), and the time constant of the same phase was higher in swimming compared with rowing and cycling (63 ± 5, 56 ± 5 and 55 ± 3 s, respectively; P < 0.001). Although both phases were well described by a double-exponential model, the differences between exercise modes had a potential effect and contributed to distinct V̇O2 off-transient kinetic patterns at 100% of V̇O2max intensity. © 2015 The Authors. Experimental Physiology © 2015 The Physiological Society.

Is exercise good for the right ventricle? Concepts for health and disease.

PubMed

La Gerche, André; Claessen, Guido

2015-04-01

There is substantial evidence supporting the prescription of exercise training in patients with left-sided heart disease, but data on the effects of exercise are far more limited for conditions that primarily affect the right ventricle. There is evolving evidence that right ventricular (RV) function is of critical importance to circulatory function during exercise. Even in healthy individuals with normal pulmonary vascular function, the hemodynamic load on the right ventricle increases relatively more during exercise than that of the left ventricle, and this disproportionate load is far greater in patients with pulmonary hypertension. Exercise-induced increases in pulmonary artery pressures can exceed RV contractile reserve (so-called arterioventricular uncoupling), resulting in attenuated cardiac output and exercise intolerance. In this review, we explore the spectrum of RV reserve-from transient RV dysfunction observed in athletes after extreme bouts of intense endurance exercise to RV failure with minimal exertion in patients with advanced pulmonary hypertension. Recent advances and novel approaches to echocardiographic and cardiac magnetic resonance imaging have provided more accurate means of assessing the right ventricle and pulmonary circulation during exercise such that quantification of exercise reserve may provide a valuable means of assessing prognosis and response to therapies. We discuss the potential benefits and risks of exercise training in both health and disease while recognizing the need for prospective studies that assess the long-term efficacy and safety of exercise interventions in patients with pulmonary vascular and RV pathologic conditions. Copyright © 2015 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.

Facilitation of the Cognitive Enhancing Effects of Working Memory Training Through Conjoint Voluntary Aerobic Exercise

PubMed Central

Smith, Andrew M.; Spiegler, Kevin M.; Sauce, Bruno; Wass, Christopher D.; Sturzoiu, Tudor; Matzel, Louis D.

2013-01-01

Increases in performance on tests of attention and learning are often observed shortly after a period of aerobic exercise, and evidence suggests that humans who engage in regular exercise are partially protected from age-related cognitive decline. However, the cognitive benefits of exercise are typically short-lived, limiting the practical application of these observations. We explored whether physical exercise would induce lasting changes in general cognitive ability if that exercise was combined with working memory training, which is purported to broadly impact on cognitive performance. Mice received either exercise (six weeks of voluntary running wheel access), working memory training, both treatments, or various control treatments. Near the completion of this period of exercise, working memory training (in a dual radial-arm maze) was initiated (alternating with days of exercise), and was continued for several weeks. Upon completion of these treatments, animals were assessed (2–4 weeks later) for performance on four diverse learning tasks, and the aggregate performance of individual animals across all four learning tasks was estimated. Working memory training alone promoted small increases in general cognitive performance, although any beneficial effects of exercise alone had dissipated by the time of learning assessments. However, the two treatments in combination more than doubled the improvement in general cognitive performance supported by working memory training alone. Unlike the transient effects that acute aerobic exercise can have on isolated learning tasks, these results indicate that an acute period of exercise combined with working memory training can have synergistic and lasting impact on general cognitive performance. PMID:24036169

Impact of sympathetic nervous system activity on post-exercise flow-mediated dilatation in humans.

PubMed

Atkinson, Ceri L; Lewis, Nia C S; Carter, Howard H; Thijssen, Dick H J; Ainslie, Philip N; Green, Daniel J

2015-12-01

Transient reduction in vascular function following systemic large muscle group exercise has previously been reported in humans. The mechanisms responsible are currently unknown. We hypothesised that sympathetic nervous system activation, induced by cycle ergometer exercise, would contribute to post-exercise reductions in flow-mediated dilatation (FMD). Ten healthy male subjects (28 ± 5 years) undertook two 30 min sessions of cycle exercise at 75% HR(max). Prior to exercise, individuals ingested either a placebo or an α1-adrenoreceptor blocker (prazosin; 0.05 mg kg(-1)). Central haemodynamics, brachial artery shear rate (SR) and blood flow profiles were assessed throughout each exercise bout and in response to brachial artery FMD, measured prior to, immediately after and 60 min after exercise. Cycle exercise increased both mean and antegrade SR (P < 0.001) with retrograde SR also elevated under both conditions (P < 0.001). Pre-exercise FMD was similar on both occasions, and was significantly reduced (27%) immediately following exercise in the placebo condition (t-test, P = 0.03). In contrast, FMD increased (37%) immediately following exercise in the prazosin condition (t-test, P = 0.004, interaction effect P = 0.01). Post-exercise FMD remained different between conditions after correction for baseline diameters preceding cuff deflation and also post-deflation SR. No differences in FMD or other variables were evident 60 min following recovery. Our results indicate that sympathetic vasoconstriction competes with endothelium-dependent dilator activity to determine post-exercise arterial function. These findings have implications for understanding the chronic impacts of interventions, such as exercise training, which affect both sympathetic activity and arterial shear stress. © 2015 The Authors. The Journal of Physiology © 2015 The Physiological Society.

A sportomics strategy to analyze the ability of arginine to modulate both ammonia and lymphocyte levels in blood after high-intensity exercise.

PubMed

Gonçalves, Luis Carlos; Bessa, Artur; Freitas-Dias, Ricardo; Luzes, Rafael; Werneck-de-Castro, João Pedro Saar; Bassini, Adriana; Cameron, Luiz-Claudio

2012-06-26

Exercise is an excellent tool to study the interactions between metabolic stress and the immune system. Specifically, high-intensity exercises both produce transient hyperammonemia and influence the distribution of white blood cells. Carbohydrates and glutamine and arginine supplementation were previously shown to effectively modulate ammonia levels during exercise. In this study, we used a short-duration, high-intensity exercise together with a low carbohydrate diet to induce a hyperammonemia state and better understand how arginine influences both ammonemia and the distribution of leukocytes in the blood. Brazilian Jiu-Jitsu practitioners (men, n = 39) volunteered for this study. The subjects followed a low-carbohydrate diet for four days before the trials and received either arginine supplementation (100 mg·kg-1 of body mass·day-1) or a placebo. The intergroup statistical significance was calculated by a one-way analysis of variance, followed by Student's t-test. The data correlations were calculated using Pearson's test. In the control group, ammonemia increased during matches at almost twice the rate of the arginine group (25 mmol·L-1·min-1 and 13 μmol·L-1·min-1, respectively). Exercise induced an increase in leukocytes of approximately 75%. An even greater difference was observed in the lymphocyte count, which increased 2.2-fold in the control group; this increase was partially prevented by arginine supplementation. The shape of the ammonemia curve suggests that arginine helps prevent increases in ammonia levels. These data indicate that increases in lymphocytes and ammonia are simultaneously reduced by arginine supplementation. We propose that increased serum lymphocytes could be related to changes in ammonemia and ammonia metabolism.

A sportomics strategy to analyze the ability of arginine to modulate both ammonia and lymphocyte levels in blood after high-intensity exercise

PubMed Central

2012-01-01

Background Exercise is an excellent tool to study the interactions between metabolic stress and the immune system. Specifically, high-intensity exercises both produce transient hyperammonemia and influence the distribution of white blood cells. Carbohydrates and glutamine and arginine supplementation were previously shown to effectively modulate ammonia levels during exercise. In this study, we used a short-duration, high-intensity exercise together with a low carbohydrate diet to induce a hyperammonemia state and better understand how arginine influences both ammonemia and the distribution of leukocytes in the blood. Methods Brazilian Jiu-Jitsu practitioners (men, n = 39) volunteered for this study. The subjects followed a low-carbohydrate diet for four days before the trials and received either arginine supplementation (100 mg·kg-1 of body mass·day-1) or a placebo. The intergroup statistical significance was calculated by a one-way analysis of variance, followed by Student’s t-test. The data correlations were calculated using Pearson’s test. Results In the control group, ammonemia increased during matches at almost twice the rate of the arginine group (25 mmol·L-1·min-1 and 13 μmol·L-1·min-1, respectively). Exercise induced an increase in leukocytes of approximately 75%. An even greater difference was observed in the lymphocyte count, which increased 2.2-fold in the control group; this increase was partially prevented by arginine supplementation. The shape of the ammonemia curve suggests that arginine helps prevent increases in ammonia levels. Conclusions These data indicate that increases in lymphocytes and ammonia are simultaneously reduced by arginine supplementation. We propose that increased serum lymphocytes could be related to changes in ammonemia and ammonia metabolism. PMID:22734448

Stroke Volume During Concomitant Apnea and Exercise: Influence of Gravity and Venous Return

NASA Astrophysics Data System (ADS)

Hoffmann, Uwe; Drager, Tobias; Steegmanns, Ansgar; Koesterer, Thomas; Linnarsson, Dag

2008-06-01

The responses of the cardiovascular system to intensive exercise (hiP) and combined stimuli by hiP and breath-hold (hiP-BH) for 20 s were examined during changing gravity (parabolic flight) and constant gravity (1g). The basic response to microgravity (μg) during low-intensity exercise was an increase in cardiac output (CO) and stroke volume (SV) as a result of augmented venous return. When onset of hiP was superimposed, the initial augmentation of CO and SV were increased further. In contrast, when BH was added, the increases of CO and SV were slowed. We propose that this was due to a transient increase of the pulmonary blood volume with the combination of μg and BH at large lung volume, creating a temporary imbalance between right ventricular input and left ventricular output. In addition, the BH- induced relative bradycardia may have contributed to a prolongation of the right-to- left indirect ventricular interdependence.

Frequency of exercise-induced ST-T-segment deviations and cardiac arrhythmias in recreational endurance athletes during a marathon race: results of the prospective observational Berlin Beat of Running study.

PubMed

Herm, Juliane; Töpper, Agnieszka; Wutzler, Alexander; Kunze, Claudia; Krüll, Matthias; Brechtel, Lars; Lock, Jürgen; Fiebach, Jochen B; Heuschmann, Peter U; Haverkamp, Wilhelm; Endres, Matthias; Jungehulsing, Gerhard Jan; Haeusler, Karl Georg

2017-08-03

While regular physical exercise has many health benefits, strenuous physical exercise may have a negative impact on cardiac function. The 'Berlin Beat of Running' study focused on feasibility and diagnostic value of continuous ECG monitoring in recreational endurance athletes during a marathon race. We hypothesised that cardiac arrhythmias and especially atrial fibrillation are frequently found in a cohort of recreational endurance athletes. The main secondary hypothesis was that pathological laboratory findings in these athletes are (in part) associated with cardiac arrhythmias. Prospective observational cohort study including healthy volunteers. One hundred and nine experienced marathon runners wore a portable ECG recorder during a marathon race in Berlin, Germany. Athletes underwent blood tests 2-3 days prior, directly after and 1-2 days after the race. Overall, 108 athletes (median 48 years (IQR 45-53), 24% women) completed the marathon in 249±43 min. Blinded ECG analysis revealed abnormal findings during the marathon in 18 (16.8%) athletes. Ten (9.3%) athletes had at least one episode of non-sustained ventricular tachycardia, one of whom had atrial fibrillation; eight (7.5%) individuals showed transient ST-T-segment deviations. Abnormal ECG findings were associated with advanced age (OR 1.11 per year, 95% CI 1.01 to 1.23), while sex and cardiovascular risk profile had no impact. Directly after the race, high-sensitive troponin T was elevated in 18 (16.7%) athletes and associated with ST-T-segment deviation (OR 9.9, 95% CI 1.9 to 51.5), while age, sex and cardiovascular risk profile had no impact. ECG monitoring during a marathon is feasible. Abnormal ECG findings were present in every sixth athlete. Exercise-induced transient ST-T-segment deviations were associated with elevated high-sensitive troponin T (hsTnT) values. ClinicalTrials.gov NCT01428778; Results. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Frequency of exercise-induced ST-T-segment deviations and cardiac arrhythmias in recreational endurance athletes during a marathon race: results of the prospective observational Berlin Beat of Running study

PubMed Central

Herm, Juliane; Töpper, Agnieszka; Wutzler, Alexander; Kunze, Claudia; Krüll, Matthias; Brechtel, Lars; Lock, Jürgen; Fiebach, Jochen B; Heuschmann, Peter U; Haverkamp, Wilhelm; Endres, Matthias; Jungehulsing, Gerhard Jan; Haeusler, Karl Georg

2017-01-01

Objectives While regular physical exercise has many health benefits, strenuous physical exercise may have a negative impact on cardiac function. The ‘Berlin Beat of Running’ study focused on feasibility and diagnostic value of continuous ECG monitoring in recreational endurance athletes during a marathon race. We hypothesised that cardiac arrhythmias and especially atrial fibrillation are frequently found in a cohort of recreational endurance athletes. The main secondary hypothesis was that pathological laboratory findings in these athletes are (in part) associated with cardiac arrhythmias. Design Prospective observational cohort study including healthy volunteers. Setting and participants One hundred and nine experienced marathon runners wore a portable ECG recorder during a marathon race in Berlin, Germany. Athletes underwent blood tests 2–3 days prior, directly after and 1–2 days after the race. Results Overall, 108 athletes (median 48 years (IQR 45–53), 24% women) completed the marathon in 249±43 min. Blinded ECG analysis revealed abnormal findings during the marathon in 18 (16.8%) athletes. Ten (9.3%) athletes had at least one episode of non-sustained ventricular tachycardia, one of whom had atrial fibrillation; eight (7.5%) individuals showed transient ST-T-segment deviations. Abnormal ECG findings were associated with advanced age (OR 1.11 per year, 95% CI 1.01 to 1.23), while sex and cardiovascular risk profile had no impact. Directly after the race, high-sensitive troponin T was elevated in 18 (16.7%) athletes and associated with ST-T-segment deviation (OR 9.9, 95% CI 1.9 to 51.5), while age, sex and cardiovascular risk profile had no impact. Conclusions ECG monitoring during a marathon is feasible. Abnormal ECG findings were present in every sixth athlete. Exercise-induced transient ST-T-segment deviations were associated with elevated high-sensitive troponin T (hsTnT) values. Trial registration ClinicalTrials.gov NCT01428778; Results. PMID:28775185

β-Adrenergic receptors desensitization is not involved in exercise-induced cardiac fatigue: NADPH oxidase-induced oxidative stress as a new trigger.

PubMed

Vitiello, Damien; Boissière, Julien; Doucende, Grégory; Gayrard, Sandrine; Polge, Anne; Faure, Patrice; Goux, Aurélie; Tanguy, Stéphane; Obert, Philippe; Reboul, Cyril; Nottin, Stéphane

2011-11-01

Prolonged strenuous exercise (PSE) induces transient left ventricular (LV) dysfunction. Previous studies suggest that β-adrenergic pathway desensitization could be involved in this phenomenon, but it remains to be confirmed. Moreover, other underlying mechanisms involving oxidative stress have been recently proposed. The present study aimed to evaluate the involvement of both the β-adrenergic pathway and NADPH oxidase (Nox) enzyme-induced oxidative stress in myocardial dysfunction in rats following PSE. Rats were divided into 4 groups: controls (Ctrl), 4-h exercised on treadmill (PSE), and 2 groups in which Nox enzyme was inhibited with apocynin treatment (Ctrl APO and PSE APO, respectively). We evaluated cardiac function in vivo and ex vivo during basal conditions and isoproterenol stress. GSH/GSSG ratio, cardiac troponin I (cTnI) release, and lipid peroxidation (MDA) were evaluated. PSE induced a decrease in LV developed pressure, intrinsic myocardial contractility, and relaxation associated with an increase in plasma cTnI release. Our in vivo and ex vivo results demonstrated no differences in myocardial response to isoproterenol and of effective dose 50 between control and PSE rats. Interestingly, the LV dysfunction was reversed by apocynin treatment. Moreover, apocynin prevented cellular oxidation [GSH/GSSG ratio: PSE APO rats vs. PSE rats in arbitrary units (au): 1.98 ± 0.07 vs. 1.35 ± 0.10; P < 0.001]. However, no differences in MDA were observed between groups. These data suggest that myocardial dysfunction observed after PSE was not due to β-adrenergic receptor desensitization but could be due to a signaling oxidative stress from the Nox enzyme.

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.

The effect of exhausting aerobic exercise on the timing of anticipatory postural adjustments.

PubMed

Strang, A J; Choi, H J; Berg, W P

2008-03-01

The aim of the study was to investigate the influence of exhausting aerobic exercise on the timing of anticipatory postural adjustments (APAs). The APAs of 12 participants were recorded at baseline, after a .VO2max running test, and again following a 45-min rest period. APAs were induced using a rapid bilateral arm-raising maneuver, and were analyzed in the rectus abdominis, hamstring group, gluteal group, and lumbar and thoracic paraspinal muscles using electromyography. Postural stability was assessed by monitoring anterior/posterior displacement of the center of pressure using a force plate. We hypothesized that APA onset would be ear lier following exhausting aerobic exercise as compared to the baseline measures, but that this effect would be transient (i.e., APA onset following the rest period would not differ from that at baseline). Exhausting aerobic exercise resulted in a significantly earlier APA in one of the 5 muscles evaluated, the thoracic paraspinal group, and this effect persisted 45-min postexercise. Exhausting aerobic exercise did not affect postural stability during the rapid arm-raising maneuver. The findings lend tentative support for the notion that earlier APAs constitute a functional adaptation by the motor system to maintain postural stability in the presence of fatigue.

Prevalence of silent myocardial ischaemia during exercise stress testing. Its relation to effort tolerance and myocardial perfusion abnormalities.

PubMed

Fragasso, G; Sciammarella, M G; Rossetti, E E; Xuereb, R G; Xuereb, M; Bonetti, F; Carandente, O M; Margonato, A; Chierchia, S L

1992-07-01

The number of underperfused myocardial segments, the extent of coronary artery disease and the severity of impairment of coronary flow reserve were compared in 147 consecutive patients exhibiting painful or painless ischaemic ST segment depression on exercise testing. Of 147 patients, only 61 (41%) experienced angina (group 1) whilst 86 (59%) did not (group 2). In the two groups coronary disease was comparable for both extent and distribution, and neither the location of transient perfusion defects nor their relation to areas of old myocardial necrosis appeared to influence the presence or absence of chest pain. However, exercise duration, exercise time and rate-pressure product at the beginning of ischaemia were lower in group 1. Furthermore, a greater proportion of asymptomatic patients had only one ischaemic segment on 99mTc-MIBI perfusion scintigraphy. We conclude that: (1) in patients with effort angina and coronary disease, the incidence of electrocardiographic silent ischaemic events induced by exercise is similar to that observed in studies based on continuous ECG monitoring. (2) Exertional angina is more frequently associated with greater ischaemic areas and with more severe degrees of impairment of residual coronary flow reserve. (3) The presence of an old myocardial infarction does not appear to influence the incidence of ischaemic cardiac pain.

Physical Activity, Health Benefits, and Mortality Risk

PubMed Central

Kokkinos, Peter

2012-01-01

A plethora of epidemiologic evidence from large studies supports unequivocally an inverse, independent, and graded association between volume of physical activity, health, and cardiovascular and overall mortality. This association is evident in apparently healthy individuals, patients with hypertension, type 2 diabetes mellitus, and cardiovascular disease, regardless of body weight. Moreover, the degree of risk associated with physical inactivity is similar to, and in some cases even stronger than, the more traditional cardiovascular risk factors. The exercise-induced health benefits are in part related to favorable modulations of cardiovascular risk factors observed by increased physical activity or structured exercise programs. Although the independent contribution of the exercise components, intensity, duration, and frequency to the reduction of mortality risk is not clear, it is well accepted that an exercise volume threshold defined at caloric expenditure of approximately 1,000 Kcal per week appears to be necessary for significant reduction in mortality risk. Further reductions in risk are observed with higher volumes of energy expenditure. Physical exertion is also associated with a relatively low and transient increase in risk for cardiac events. This risk is significantly higher for older and sedentary individuals. Therefore, such individuals should consult their physician prior to engaging in exercise. “Walking is man’s best medicine”Hippocrates PMID:23198160

Assessment of residual tissue viability by exercise testing in recent myocardial infarction: comparison of the electrocardiogram and myocardial perfusion scintigraphy.

PubMed

Margonato, A; Ballarotto, C; Bonetti, F; Cappelletti, A; Sciammarella, M; Cianflone, D; Chierchia, S L

1992-04-01

The assessment of residual myocardial viability in infarcted areas is relevant for subsequent management and prognosis but requires expensive technology. To evaluate the possibility that simple, easily obtainable clinical markers may detect the presence of within-infarct viable tissue, the significance of exercise-induced ST elevation occurring in leads exploring the area of a recent Q wave myocardial infarction was assessed. Twenty-five patients with recent (less than 6 months) myocardial infarction were studied. All had angiographically documented coronary artery disease, diagnostic Q waves (n = 24) or negative T waves (n = 25) on the rest 12-lead electrocardiogram and exhibited during exercise greater than or equal to 1.5 mm ST segment elevation (n = 17) or isolated T wave pseudonormalization (n = 8) in the infarct-related leads. ST-T wave changes were reproduced in all patients during thallium-201 exercise myocardial scintigraphy. A fixed perfusion defect was observed in 24 of the 25 patients. A reversible defect was seen in 16 (94%) of 17 patients who exhibited transient ST elevation during exercise but in only 4 (50%) of the 8 patients who had only T wave pseudonormalization. In conclusion, in patients with recent myocardial infarction, analysis of simple ST segment variables obtained during exercise testing may allow a first-line discrimination of those who may potentially benefit from a revascularization procedure.

Exercise training and muscle microvascular oxygenation: functional role of nitric oxide

PubMed Central

Hirai, Daniel M.; Copp, Steven W.; Ferguson, Scott K.; Holdsworth, Clark T.; McCullough, Danielle J.; Behnke, Bradley J.; Musch, Timothy I.

2012-01-01

Exercise training induces multiple adaptations within skeletal muscle that may improve local O2 delivery-utilization matching (i.e., Po2mv). We tested the hypothesis that increased nitric oxide (NO) function is intrinsic to improved muscle Po2mv kinetics from rest to contractions after exercise training. Healthy young Sprague-Dawley rats were assigned to sedentary (n = 18) or progressive treadmill exercise training (n = 10; 5 days/wk, 6–8 wk, final workload of 60 min/day at 35 m/min, −14% grade) groups. Po2mv was measured via phosphorescence quenching in the spinotrapezius muscle at rest and during 1-Hz twitch contractions under control (Krebs-Henseleit solution), sodium nitroprusside (SNP, NO donor; 300 μM), and NG-nitro-l-arginine methyl ester (l-NAME, nonspecific NO synthase blockade; 1.5 mM) superfusion conditions. Exercise-trained rats had greater peak oxygen uptake (V̇o2peak) than their sedentary counterparts (81 ± 1 vs. 72 ± 2 ml·kg−1·min−1, respectively; P < 0.05). Exercise-trained rats had significantly slower Po2mv fall throughout contractions (τ1; time constant for the first component) during control (sedentary: 8.1 ± 0.6; trained: 15.2 ± 2.8 s). Compared with control, SNP slowed τ1 to a greater extent in sedentary rats (sedentary: 38.7 ± 5.6; trained: 26.8 ± 4.1 s; P > 0.05) whereas l-NAME abolished the differences in τ1 between sedentary and trained rats (sedentary: 12.0 ± 1.7; trained: 11.2 ± 1.4 s; P < 0.05). Our results indicate that endurance exercise training leads to greater muscle microvascular oxygenation across the metabolic transient following the onset of contractions (i.e., slower Po2mv kinetics) partly via increased NO-mediated function, which likely constitutes an important mechanism for training-induced metabolic adaptations. PMID:22678970

Acute impact of conventional and eccentric cycling on platelet and vascular function in patients with chronic heart failure.

PubMed

Haynes, Andrew; Linden, Matthew D; Chasland, Lauren C; Nosaka, Kazunori; Maiorana, Andrew; Dawson, Ellen A; Dembo, Lawrence H; Naylor, Louise H; Green, Daniel J

2017-06-01

Evidence-based guidelines recommend exercise therapy for patients with chronic heart failure (CHF). Such patients have increased atherothrombotic risk. Exercise can transiently increase platelet activation and reactivity and decrease vascular function in healthy participants, although data in CHF are scant. Eccentric (ECC) cycling is a novel exercise modality that may be particularly suited to patients with CHF, but the acute impacts of ECC cycling on platelet and vascular function are currently unknown. Our null hypothesis was that ECC and concentric (CON) cycling, performed at matched external workloads, would not induce changes in platelet or vascular function in patients with CHF. Eleven patients with heart failure with reduced ejection fraction (HFrEF) took part in discrete bouts of ECC and CON cycling. Before and immediately after exercise, vascular function was assessed by measuring diameter and flow-mediated dilation (FMD) of the brachial artery. Platelet function was measured by the flow cytometric determination of glycoprotein IIb/IIIa activation and granule exocytosis in the presence and absence of platelet agonists. ECC cycling increased baseline artery diameter (pre: 4.0 ± 0.8 mm vs. post: 4.2 ± 0.7 mm; P = 0.04) and decreased FMD%. When changes in baseline artery diameter were accounted for, the decrease in FMD post-ECC cycling was no longer significant. No changes were apparent after CON. Neither ECC nor CON cycling resulted in changes to any platelet-function measures (all P > 0.05). These results suggest that both ECC and CON cycling, at a moderate intensity and short duration, can be performed by patients with HFrEF without detrimental impacts on vascular or platelet function. NEW & NOTEWORTHY This is the first evidence to indicate that eccentric (ECC) cycling can be performed relatively safely by patients with chronic heart failure (CHF), as it did not result in impaired vascular or platelet function compared with conventional cycling. This is important, as acute exercise can transiently increase atherothrombotic risk, and ECC cycling is a novel exercise modality that may be particularly suited to patients with CHF. Copyright © 2017 the American Physiological Society.

Myocellular limitations of human performance and their modification through genome-dependent responses at altitude.

PubMed

Flueck, Martin

2010-03-01

Human muscle operates along a continuum of power output, which is set through bioenergetic and anatomical principles. In turn, environmental and intrinsic factors during contractile work exert pronounced control over muscle performance by instructing muscle remodelling. This phenotypic control is specifically indicated with intense exercise at altitude, when extra strain is put on energy supply and the temperature-dependent mechanical efficiency of contraction. While it is classically thought that chronic exposure to hypoxia is maladaptive, repeated short episodes of reduced oxygenation alone or in combination with intense endurance work is now understood to preserve exercise performance when atmospheric oxygen levels are low. Endurance training at moderate altitude exploits the temperature-dependent malleability of energy supply that may maximize metabolic flux at altitude. The contribution of genomic mechanisms is important to the plasticity of metabolic pathways in exercised muscle. This is highlighted by the association of distinct gene polymorphisms in master governors of mitochondrial and vascular growth with exercise phenotypes. Feedforward control of human locomoter muscle by exercise involves the transient upregulation of transcript expression for metabolic processes. The response of the mitochondrial transcriptome to intense exercise is graded with respect to mitochondrial content and deoxygenation during muscle work and reflects exercise-induced mitochondrial biogenesis. This supports the notion that genome-mediated muscle malleability is under feedback control by design constraints of the pathway of oxygen. Thus, activity-dependent and genetic mechanisms contribute to the interindividual difference in the metabolic bottlenecks in athletes performing in exceptional environmental conditions.

Protection against severe hypokalemia but impaired cardiac repolarization after intense rowing exercise in healthy humans receiving salbutamol.

PubMed

Atanasovska, Tania; Smith, Robert; Graff, Claus; Tran, Cao Thach; Melgaard, Jacob; Kanters, Jørgen K; Petersen, Aaron C; Tobin, Antony; Kjeldsen, Keld P; McKenna, Michael John

2018-05-10

Intense exercise induces pronounced hyperkalemia, followed by transient hypokalemia in recovery. We investigated whether the β 2 -agonist salbutamol attenuated the exercise-hyperkalemia, and exacerbated the post-exercise hypokalemia, and whether hypokalemia was associated with impaired cardiac repolarization (QT hysteresis). Eleven healthy adults participated in a randomized, counterbalanced, double-blind trial receiving either 1000 µg salbutamol (SAL) or placebo (PLAC) by inhalation. Arterial plasma potassium concentration ([K + ] a ) was measured at rest, during 3 min intense rowing exercise and 60 min recovery. QT hysteresis was calculated from ECG (n=8). [K + ] a increased above baseline during exercise (rest, 3.72{plus minus}0.7 vs end-exercise, 6.81{plus minus}1.4 mM, P<0.001, mean{plus minus}SD) and decreased rapidly during early recovery to below baseline; restoration was incomplete at 60 min post-exercise (P<0.05). [K + ] a was less during SAL than PLAC (4.39{plus minus}0.13 vs. 4.73{plus minus}0.19 mM, pooled across all times, P=0.001, treatment main effect). [K + ] a was lower after SAL than PLAC, from 2 min pre-exercise until 2.5 min during exercise, and at 50 and 60 min post-exercise (P<0.05). The post-exercise decline in [K + ] a was correlated with QT hysteresis (r=0.343, n=112, pooled data, P=0.001). Thus the decrease in [K + ] a from end-exercise by ~4 mM was associated with reduced QT hysteresis by ~75 ms. Whilst salbutamol lowered [K + ] a during exercise, no additive hypokalemic effects occurred in early recovery, suggesting there may be a protective mechanism against severe or prolonged hypokalemia after exercise when treated by salbutamol. This is important since post-exercise hypokalemia impaired cardiac repolarization, which could potentially trigger arrhythmias and sudden cardiac death in susceptible individuals with pre-existing hypokalemia and/or heart disease.

Effect of inspired air conditions on exercise-induced bronchoconstriction and urinary CC16 levels in athletes.

PubMed

Bolger, C; Tufvesson, E; Anderson, S D; Devereux, G; Ayres, J G; Bjermer, L; Sue-Chu, M; Kippelen, P

2011-10-01

Injury to the airway epithelium has been proposed as a key susceptibility factor for exercise-induced bronchoconstriction (EIB). Our goals were to establish whether airway epithelial cell injury occurs during EIB in athletes and whether inhalation of warm humid air inhibits this injury. Twenty-one young male athletes (10 with a history of EIB) performed two 8-min exercise tests near maximal aerobic capacity in cold dry (4°C, 37% relative humidity) and warm humid (25°C, 94% relative humidity) air on separate days. Postexercise changes in urinary CC16 were used as a biomarker of airway epithelial cell perturbation and injury. Bronchoconstriction occurred in eight athletes in the cold dry environment and was completely blocked by inhalation of warm humid air [maximal fall in forced expiratory volume in 1 s = 18.1 ± 2.1% (SD) in cold dry air and 1.7 ± 0.8% in warm humid air, P < 0.01]. Exercise caused an increase in urinary excretion of CC16 in all subjects (P < 0.001), but this rise in CC16 was blunted following inhalation of warm humid air [median CC16 increase pre- to postchallenge = 1.91 and 0.35 ng/μmol in cold dry and warm humid air, respectively, in athletes with EIB (P = 0.017) and 1.68 and 0.48 ng/μmol in cold dry and warm humid air, respectively, in athletes without EIB (P = 0.002)]. The results indicate that exercise hyperpnea transiently disrupts the airway epithelium of all athletes (not only in those with EIB) and that inhalation of warm moist air limits airway epithelial cell perturbation and injury.

[Acute stent thrombosis and reverse transient left ventricular dilatation after performing a single-photon emission computed tomography myocardial perfusion].

PubMed

Miranda, B; Pizzi, M N; Aguadé-Bruix, S; Domingo, E; Candell-Riera, J

2015-01-01

A 63-year-old male patient with a history of stent implantation in the left anterior descending three months before. Due to the presentation of vegetative symptoms, he was referred for gated-SPECT myocardial perfusion. During acquisition of the resting images he presented chest pain and ST segment elevation, so that urgent cardiac catheterization was performed, showing stent thrombosis. Rest perfusion imaging showed a defect in anterior and apical perfusion, more severe and extensive than in the stress images, with striking left ventricular dilatation and a fall in the ejection fraction related to the acute ischemia phenomenon. Intense exercise is associated with a transient activation of the coagulation system and hemodynamic changes that might induce thrombosis, especially in recently implanted coronary stents that probably still have not become completely endothelialized. Copyright © 2014 Elsevier España, S.L.U. y SEMNIM. All rights reserved.

Exercise, appetite and appetite-regulating hormones: implications for food intake and weight control.

PubMed

Stensel, David

2010-01-01

Knowledge about the relationship between exercise and appetite is important both for athletes wishing to optimise performance and for those interested in maintaining a healthy body weight. A variety of hormones are involved in appetite regulation including both episodic hormones, which are responsive to episodes of feeding, and tonic hormones, which are important regulators of energy storage over the longer term (e.g. insulin and leptin). Notable among the episodic appetite-regulating hormones is ghrelin, which plays a unique role in stimulating appetite and energy intake. Many studies have demonstrated that acute bouts of moderately vigorous exercise transiently suppress appetite and this has been termed 'exercise-induced anorexia'. The mechanisms by which acute exercise suppresses appetite are not fully understood but may involve lowered concentrations of ghrelin and increased concentrations of satiety hormones, notably peptide YY and glucagon-like peptide 1. Evidence suggests that chronic exercise training typically causes a partial but incomplete compensation in energy intake perhaps due to beneficial changes in appetite-regulating hormones. The lack of a full compensatory response of appetite to exercise may facilitate the development of a negative energy balance and weight loss although there is individual variability in the response to exercise. From a practical standpoint athletes should not feel concerned that exercise will cause overeating as there is limited evidence to support this. For those desiring weight loss there may be some merit in performing exercise in the postprandial period as a means of enhancing the satiating effect of a meal but additional evidence is required to confirm the effectiveness of this strategy. Copyright © 2011 S. Karger AG, Basel.

[Bronchial hyperreactivity in athletes].

PubMed

Carlsen, K H

1994-01-01

Elite athletics, particularly endurance sports, are characterised by a high prevalence of bronchial hyperresponsiveness (BHR) and exercise-induced asthma (EIA). Findings in several studies suggest short-term high intensity physical activity to cause a transient increase in BHR. Recent studies in Oslo have shown that regular physical endurance training over several years, particularly when combined with such climatic factors as low air temperatures, may result in an increased risk of BHR and EIA among elite athletes--e.g., cross-country skiers. Inhalation beta 2-agonists and steroids have been used by many athletes in endurance sports, particularly skiers. Athletes with symptoms of BHR or EIA should be examined with lung function tests and exercise testing, and the effect of antiasthmatic drugs should be ascertained. Inhaled beta 2-agonists have no beneficial effect upon physical performance in nonasthmatic athletes, and may have a slight limiting effect upon physical endurance.

ROS Production via P2Y1-PKC-NOX2 Is Triggered by Extracellular ATP after Electrical Stimulation of Skeletal Muscle Cells.

PubMed

Díaz-Vegas, Alexis; Campos, Cristian A; Contreras-Ferrat, Ariel; Casas, Mariana; Buvinic, Sonja; Jaimovich, Enrique; Espinosa, Alejandra

2015-01-01

During exercise, skeletal muscle produces reactive oxygen species (ROS) via NADPH oxidase (NOX2) while inducing cellular adaptations associated with contractile activity. The signals involved in this mechanism are still a matter of study. ATP is released from skeletal muscle during electrical stimulation and can autocrinely signal through purinergic receptors; we searched for an influence of this signal in ROS production. The aim of this work was to characterize ROS production induced by electrical stimulation and extracellular ATP. ROS production was measured using two alternative probes; chloromethyl-2,7- dichlorodihydrofluorescein diacetate or electroporation to express the hydrogen peroxide-sensitive protein Hyper. Electrical stimulation (ES) triggered a transient ROS increase in muscle fibers which was mimicked by extracellular ATP and was prevented by both carbenoxolone and suramin; antagonists of pannexin channel and purinergic receptors respectively. In addition, transient ROS increase was prevented by apyrase, an ecto-nucleotidase. MRS2365, a P2Y1 receptor agonist, induced a large signal while UTPyS (P2Y2 agonist) elicited a much smaller signal, similar to the one seen when using ATP plus MRS2179, an antagonist of P2Y1. Protein kinase C (PKC) inhibitors also blocked ES-induced ROS production. Our results indicate that physiological levels of electrical stimulation induce ROS production in skeletal muscle cells through release of extracellular ATP and activation of P2Y1 receptors. Use of selective NOX2 and PKC inhibitors suggests that ROS production induced by ES or extracellular ATP is mediated by NOX2 activated by PKC.

Probiotic Supplements Beneficially Affect Tryptophan–Kynurenine Metabolism and Reduce the Incidence of Upper Respiratory Tract Infections in Trained Athletes: A Randomized, Double-Blinded, Placebo-Controlled Trial

PubMed Central

Strasser, Barbara; Geiger, Daniela; Schauer, Markus; Gostner, Johanna M.; Gatterer, Hannes; Burtscher, Martin; Fuchs, Dietmar

2016-01-01

Background: Prolonged intense exercise has been associated with transient suppression of immune function and an increased risk of infections. In this context, the catabolism of amino acid tryptophan via kynurenine may play an important role. The present study examined the effect of a probiotic supplement on the incidence of upper respiratory tract infections (URTI) and the metabolism of aromatic amino acids after exhaustive aerobic exercise in trained athletes during three months of winter training. Methods: Thirty-three highly trained individuals were randomly assigned to probiotic (PRO, n = 17) or placebo (PLA, n = 16) groups using double blind procedures, receiving either 1 × 1010 colony forming units (CFU) of a multi-species probiotic (Bifidobacterium bifidum W23, Bifidobacterium lactis W51, Enterococcus faecium W54, Lactobacillus acidophilus W22, Lactobacillus brevis W63, and Lactococcus lactis W58) or placebo once per day for 12 weeks. The serum concentrations of tryptophan, phenylalanine and their primary catabolites kynurenine and tyrosine, as well as the concentration of the immune activation marker neopterin were determined at baseline and after 12 weeks, both at rest and immediately after exercise. Participants completed a daily diary to identify any infectious symptoms. Results: After 12 weeks of treatment, post-exercise tryptophan levels were lowered by 11% (a significant change) in the PLA group compared to the concentrations measured before the intervention (p = 0.02), but remained unchanged in the PRO group. The ratio of subjects taking the placebo who experienced one or more URTI symptoms was increased 2.2-fold compared to those on probiotics (PLA 0.79, PRO 0.35; p = 0.02). Conclusion: Data indicate reduced exercise-induced tryptophan degradation rates in the PRO group. Daily supplementation with probiotics limited exercise-induced drops in tryptophan levels and reduced the incidence of URTI, however, did not benefit athletic performance. PMID:27886064

TRPC3-Nox2 complex mediates doxorubicin-induced myocardial atrophy

PubMed Central

Shimauchi, Tsukasa; Numaga-Tomita, Takuro; Ito, Tomoya; Nishimura, Akiyuki; Matsukane, Ryosuke; Oda, Sayaka; Hoka, Sumio; Ide, Tomomi; Koitabashi, Norimichi; Uchida, Koji; Sumimoto, Hideki; Mori, Yasuo

2017-01-01

Myocardial atrophy is a wasting of cardiac muscle due to hemodynamic unloading. Doxorubicin is a highly effective anticancer agent but also induces myocardial atrophy through a largely unknown mechanism. Here, we demonstrate that inhibiting transient receptor potential canonical 3 (TRPC3) channels abolishes doxorubicin-induced myocardial atrophy in mice. Doxorubicin increased production of ROS in rodent cardiomyocytes through hypoxic stress–mediated upregulation of NADPH oxidase 2 (Nox2), which formed a stable complex with TRPC3. Cardiomyocyte-specific expression of TRPC3 C-terminal minipeptide inhibited TRPC3-Nox2 coupling and suppressed doxorubicin-induced reduction of myocardial cell size and left ventricular (LV) dysfunction, along with its upregulation of Nox2 and oxidative stress, without reducing hypoxic stress. Voluntary exercise, an effective treatment to prevent doxorubicin-induced cardiotoxicity, also downregulated the TRPC3-Nox2 complex and promoted volume load–induced LV compliance, as demonstrated in TRPC3-deficient hearts. These results illustrate the impact of TRPC3 on LV compliance and flexibility and, focusing on the TRPC3-Nox2 complex, provide a strategy for prevention of doxorubicin-induced cardiomyopathy. PMID:28768915

Exercise-Induced Asthma

MedlinePlus

... Videos for Educators Search English Español Exercise-Induced Asthma KidsHealth / For Parents / Exercise-Induced Asthma What's in ... Exercise-Induced Asthma Print What Is Exercise-Induced Asthma? Most kids and teens with asthma have symptoms ...

Transient enhancement of GLUT-4 levels in rat epitrochlearis muscle after exercise training

PubMed Central

Reynolds, Thomas H.; Brozinick, Joseph T.; Larkin, Lisa M.; Cushman, Samuel W.

2009-01-01

The purpose of the present study was to examine the effect of detraining on the glucose transport system after short-term swim training (5 days), long-term swim training (5 wk), and treadmill run training (5 wk). Skeletal muscles were isolated from female Wistar rats at 24 or 48 h posttraining. SST produces a 48% increase in GLUT-4 mRNA, a 30% increase in GLUT-4 protein, and a 60% increase in insulin-stimulated glucose transport activity at 24 h posttraining but not at 48 h posttraining. Similar to SST, long-term swim training produces a 60% increase in GLUT-4 mRNA and a 30% increase in GLUT-4 protein content at 24 h posttraining but not at 48 h posttraining. Finally, treadmill run training produces a transient 35% increase in GLUT-4 protein content that is completely reversed at 48 h after the last bout of exercise. These results demonstrate that the increase in GLUT-4 mRNA and GLUT-4 protein occurs during the first week of exercise training and is rapidly lost after training cessation. We believe that the transient enhancement in GLUT-4 protein after exercise training is due to a short GLUT-4 half-life, a process that is primarily regulated by pretranslational mechanisms. PMID:10846041

Transient enhancement of GLUT-4 levels in rat epitrochlearis muscle after exercise training.

PubMed

Reynolds, T H; Brozinick, J T; Larkin, L M; Cushman, S W

2000-06-01

The purpose of the present study was to examine the effect of detraining on the glucose transport system after short-term swim training (5 days), long-term swim training (5 wk), and treadmill run training (5 wk). Skeletal muscles were isolated from female Wistar rats at 24 or 48 h posttraining. SST produces a 48% increase in GLUT-4 mRNA, a 30% increase in GLUT-4 protein, and a 60% increase in insulin-stimulated glucose transport activity at 24 h posttraining but not at 48 h posttraining. Similar to SST, long-term swim training produces a 60% increase in GLUT-4 mRNA and a 30% increase in GLUT-4 protein content at 24 h posttraining but not at 48 h posttraining. Finally, treadmill run training produces a transient 35% increase in GLUT-4 protein content that is completely reversed at 48 h after the last bout of exercise. These results demonstrate that the increase in GLUT-4 mRNA and GLUT-4 protein occurs during the first week of exercise training and is rapidly lost after training cessation. We believe that the transient enhancement in GLUT-4 protein after exercise training is due to a short GLUT-4 half-life, a process that is primarily regulated by pretranslational mechanisms.

Exercise-Induced Bronchoconstriction Quiz

MedlinePlus

... navigation Home ▸ Conditions & Treatments ▸ Asthma ▸ EIB Quiz Share | Exercise-Induced Bronchoconstriction or Exercise-Induced Asthma Quiz Exercise-Induced Bronchoconstriction (also called ...

Debunking the Myth of Exercise-Induced Immune Suppression: Redefining the Impact of Exercise on Immunological Health Across the Lifespan.

PubMed

Campbell, John P; Turner, James E

2018-01-01

Epidemiological evidence indicates that regular physical activity and/or frequent structured exercise reduces the incidence of many chronic diseases in older age, including communicable diseases such as viral and bacterial infections, as well as non-communicable diseases such as cancer and chronic inflammatory disorders. Despite the apparent health benefits achieved by leading an active lifestyle, which imply that regular physical activity and frequent exercise enhance immune competency and regulation, the effect of a single bout of exercise on immune function remains a controversial topic. Indeed, to this day, it is perceived by many that a vigorous bout of exercise can temporarily suppress immune function. In the first part of this review, we deconstruct the key pillars which lay the foundation to this theory-referred to as the "open window" hypothesis-and highlight that: (i) limited reliable evidence exists to support the claim that vigorous exercise heightens risk of opportunistic infections; (ii) purported changes to mucosal immunity, namely salivary IgA levels, after exercise do not signpost a period of immune suppression; and (iii) the dramatic reductions to lymphocyte numbers and function 1-2 h after exercise reflects a transient and time-dependent redistribution of immune cells to peripheral tissues, resulting in a heightened state of immune surveillance and immune regulation, as opposed to immune suppression. In the second part of this review, we provide evidence that frequent exercise enhances-rather than suppresses-immune competency, and highlight key findings from human vaccination studies which show heightened responses to bacterial and viral antigens following bouts of exercise. Finally, in the third part of this review, we highlight that regular physical activity and frequent exercise might limit or delay aging of the immune system, providing further evidence that exercise is beneficial for immunological health. In summary, the over-arching aim of this review is to rebalance opinion over the perceived relationships between exercise and immune function. We emphasize that it is a misconception to label any form of acute exercise as immunosuppressive, and, instead, exercise most likely improves immune competency across the lifespan.

Trade-offs between anti-aging dietary supplementation and exercise.

PubMed

Mendelsohn, Andrew R; Larrick, James W

2013-10-01

In otherwise healthy adults, moderate aerobic exercise extends life span and likely health span by 2-6 years. Exercise improves blood sugar regulation, and resistance exercise increases or maintains muscle mass and is associated with improved cognitive function. On the other hand, evidence for anti-oxidant supplements increasing longevity in humans is lacking. On the contrary, transient hormetic increases in reactive oxygen species (ROS), for example, associated with exercise, are actually associated with increased mammalian health span and life span. Recent studies in humans suggest that anti-oxidants such as vitamins C, E, resveratrol, and acetyl-N-cysteine blunt the beneficial effects of exercise on glucose sensitivity and blood sugar regulation, likely through direct inhibition of ROS signaling. Alternately, other studies suggest that vitamin C has beneficial effects on exercise-associated dysfunction, inhibiting exercise-induced bronchioconstriction. These data suggest that there are tradeoffs between potential benefits and harm from anti-oxidant dietary supplementation. Specific biomolecular interactions for each antioxidant also will be important. Omega-3 (n-3) polyunsaturated fattty acids (PUFAs) have anti-inflammatory activity that is not mediated through direct ROS inhibition. Although data are limited in humans, n-3 PUFAs do not seem to blunt blood sugar regulatory benefits of aerobic exercise and actually increase anabolic activity in skeletal muscle. However, another kind of tradeoff may exist with PUFAs, at least for men. A recent large clinical trial demonstrates an association of omega-3 fatty acids blood levels with increased incidence of prostate cancer, especially aggressive prostate cancer. Together these results suggest that there are significant tradeoffs in the use of dietary supplementation for prevention and treatment of diseases associated with aging. Such tradeoffs may result from underlying intertwined homeostatic mechanisms. For most individuals, moderate exercise is of significant benefit. Careful attention to individual and family medical history and personal genomic data may prove essential to make wise dietary and supplement choices to be combined with exercise.

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.

PHISICS/RELAP5-3D RESULTS FOR EXERCISES II-1 AND II-2 OF THE OECD/NEA MHTGR-350 BENCHMARK

DOE Office of Scientific and Technical Information (OSTI.GOV)

Strydom, Gerhard

2016-03-01

The Idaho National Laboratory (INL) Advanced Reactor Technologies (ART) High-Temperature Gas-Cooled Reactor (HTGR) Methods group currently leads the Modular High-Temperature Gas-Cooled Reactor (MHTGR) 350 benchmark. The benchmark consists of a set of lattice-depletion, steady-state, and transient problems that can be used by HTGR simulation groups to assess the performance of their code suites. The paper summarizes the results obtained for the first two transient exercises defined for Phase II of the benchmark. The Parallel and Highly Innovative Simulation for INL Code System (PHISICS), coupled with the INL system code RELAP5-3D, was used to generate the results for the Depressurized Conductionmore » Cooldown (DCC) (exercise II-1a) and Pressurized Conduction Cooldown (PCC) (exercise II-2) transients. These exercises require the time-dependent simulation of coupled neutronics and thermal-hydraulics phenomena, and utilize the steady-state solution previously obtained for exercise I-3 of Phase I. This paper also includes a comparison of the benchmark results obtained with a traditional system code “ring” model against a more detailed “block” model that include kinetics feedback on an individual block level and thermal feedbacks on a triangular sub-mesh. The higher spatial fidelity that can be obtained by the block model is illustrated with comparisons of the maximum fuel temperatures, especially in the case of natural convection conditions that dominate the DCC and PCC events. Differences up to 125 K (or 10%) were observed between the ring and block model predictions of the DCC transient, mostly due to the block model’s capability of tracking individual block decay powers and more detailed helium flow distributions. In general, the block model only required DCC and PCC calculation times twice as long as the ring models, and it therefore seems that the additional development and calculation time required for the block model could be worth the gain that can be obtained in the spatial resolution« less

Heat acclimation and exercise training interact when combined in an overriding and trade-off manner: physiologic-genomic linkage

PubMed Central

Kodesh, Einat; Nesher, Nir; Simaan, Assi; Hochner, Benny; Beeri, Ronen; Gilon, Dan; Stern, Michael D.; Gerstenblith, Gary

2011-01-01

Combined heat acclimation (AC) and exercise training (EX) enhance exercise performance in the heat while meeting thermoregulatory demands. We tested the hypothesis that different stress-specific adaptations evoked by each stressor individually trigger similar cardiac alterations, but when combined, overriding/trade-off interactions take place. We used echocardiography, isolated cardiomyocyte imaging and cDNA microarray techniques to assay in situ cardiac performance, excitation-contraction (EC) coupling features, and transcriptional programs associated with cardiac contractility. Rat groups studied were controls (sedentary 24°C); AC (sedentary, 34°C, 1 mo); normothermic EX (treadmill at 24°C, 1 mo); and heat-acclimated, exercise-trained (EXAC; treadmill at 34°C, 1 mo). Prolonged heat exposure decreased heart rate and contractile velocity and increased end ventricular diastolic diameter. Compared with controls, AC/EXAC cardiomyocytes demonstrated lower l-type Ca2+ current (ICaL) amplitude, higher Ca2+ transient (Ca2+T), and a greater Ca2+T-to-ICaL ratio; EX alone enhanced ICaL and Ca2+T, whereas aerobic training in general induced cardiac hypertrophy and action potential elongation in EX/EXAC animals. At the genomic level, the transcriptome profile indicated that the interaction between AC and EX yields an EXAC-specific molecular program. Genes affected by chronic heat were linked with the EC coupling cascade, whereas aerobic training upregulated genes involved with Ca2+ turnover via an adrenergic/metabolic-driven positive inotropic response. In the EXAC cardiac phenotype, the impact of chronic heat overrides that of EX on EC coupling components and heart rate, whereas EX regulates cardiac morphometry. We suggest that concerted adjustments induced by AC and EX lead to enhanced metabolic and mechanical performance of the EXAC heart. PMID:21957158

The effect of inter-set rest intervals on resistance exercise-induced muscle hypertrophy.

PubMed

Henselmans, Menno; Schoenfeld, Brad J

2014-12-01

Due to a scarcity of longitudinal trials directly measuring changes in muscle girth, previous recommendations for inter-set rest intervals in resistance training programs designed to stimulate muscular hypertrophy were primarily based on the post-exercise endocrinological response and other mechanisms theoretically related to muscle growth. New research regarding the effects of inter-set rest interval manipulation on resistance training-induced muscular hypertrophy is reviewed here to evaluate current practices and provide directions for future research. Of the studies measuring long-term muscle hypertrophy in groups employing different rest intervals, none have found superior muscle growth in the shorter compared with the longer rest interval group and one study has found the opposite. Rest intervals less than 1 minute can result in acute increases in serum growth hormone levels and these rest intervals also decrease the serum testosterone to cortisol ratio. Long-term adaptations may abate the post-exercise endocrinological response and the relationship between the transient change in hormonal production and chronic muscular hypertrophy is highly contentious and appears to be weak. The relationship between the rest interval-mediated effect on immune system response, muscle damage, metabolic stress, or energy production capacity and muscle hypertrophy is still ambiguous and largely theoretical. In conclusion, the literature does not support the hypothesis that training for muscle hypertrophy requires shorter rest intervals than training for strength development or that predetermined rest intervals are preferable to auto-regulated rest periods in this regard.

ROS Production via P2Y1-PKC-NOX2 Is Triggered by Extracellular ATP after Electrical Stimulation of Skeletal Muscle Cells

PubMed Central

Díaz-Vegas, Alexis; Campos, Cristian A.; Contreras-Ferrat, Ariel; Casas, Mariana; Buvinic, Sonja; Jaimovich, Enrique; Espinosa, Alejandra

2015-01-01

During exercise, skeletal muscle produces reactive oxygen species (ROS) via NADPH oxidase (NOX2) while inducing cellular adaptations associated with contractile activity. The signals involved in this mechanism are still a matter of study. ATP is released from skeletal muscle during electrical stimulation and can autocrinely signal through purinergic receptors; we searched for an influence of this signal in ROS production. The aim of this work was to characterize ROS production induced by electrical stimulation and extracellular ATP. ROS production was measured using two alternative probes; chloromethyl-2,7- dichlorodihydrofluorescein diacetate or electroporation to express the hydrogen peroxide-sensitive protein Hyper. Electrical stimulation (ES) triggered a transient ROS increase in muscle fibers which was mimicked by extracellular ATP and was prevented by both carbenoxolone and suramin; antagonists of pannexin channel and purinergic receptors respectively. In addition, transient ROS increase was prevented by apyrase, an ecto-nucleotidase. MRS2365, a P2Y1 receptor agonist, induced a large signal while UTPyS (P2Y2 agonist) elicited a much smaller signal, similar to the one seen when using ATP plus MRS2179, an antagonist of P2Y1. Protein kinase C (PKC) inhibitors also blocked ES-induced ROS production. Our results indicate that physiological levels of electrical stimulation induce ROS production in skeletal muscle cells through release of extracellular ATP and activation of P2Y1 receptors. Use of selective NOX2 and PKC inhibitors suggests that ROS production induced by ES or extracellular ATP is mediated by NOX2 activated by PKC. PMID:26053483

Beneficial effects of neuropeptide galanin on reinstatement of exercise-induced somatic and psychological trauma.

PubMed

He, Biao; Fang, Penghua; Guo, Lili; Shi, Mingyi; Zhu, Yan; Xu, Bo; Bo, Ping; Zhang, Zhenwen

2017-04-01

Galanin is a versatile neuropeptide that is distinctly upregulated by exercise in exercise-related tissues. Although benefits from exercise-induced upregulation of this peptide have been identified, many issues require additional exploration. This Review summarizes the information currently available on the relationship between galanin and exercise-induced physical and psychological damage. On the one hand, body movement, exercise damage, and exercise-induced stress and pain significantly increase local and circulatory galanin levels. On the other hand, galanin plays an exercise-protective role to inhibit the flexor reflex and prevent excessive movement of skeletal muscles through enhancing response threshold and reducing acetylcholine release. Additionally, elevated galanin levels can boost repair of the exercise-induced damage in exercise-related tissues, including peripheral nerve, skeletal muscle, blood vessel, skin, bone, articulation, and ligament. Moreover, elevated galanin levels may serve as effective signals to buffer sport-induced stress and pain via inhibiting nociceptive signal transmission and enhancing pain threshold. This Review deepens our understanding of the profitable roles of galanin in exercise protection, exercise injury repair, and exercise-induced stress and pain. Galanin and its agonists may be used to develop a novel preventive and therapeutic strategy to prevent and treat exercise-induced somatic and psychological trauma. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Acute Exercise Improves Mood and Motivation in Young Men with ADHD Symptoms.

PubMed

Fritz, Kathryn M; O'Connor, Patrick J

2016-06-01

Little is known about whether acute exercise affects signs or symptoms of attention deficit/hyperactivity disorder (ADHD) in adults. This experiment sought to determine the effects of a single bout of moderate-intensity leg cycling exercise on measures of attention, hyperactivity, mood, and motivation to complete mental work in adult men reporting elevated ADHD symptoms. A repeated-measures crossover experiment was conducted with 32 adult men (18-33 yr) with symptoms consistent with adult ADHD assessed by the Adult Self-Report Scale V1.1. Measures of attention (continuous performance task and Bakan vigilance task), motivation to perform the mental work (visual analog scale), lower leg physical activity (accelerometry), and mood (Profile of Mood States and Addiction Research Center Inventory amphetamine scale) were measured before and twice after a 20-min seated rest control or exercise condition involving cycling at 65% V˙O2peak. Condition (exercise vs rest) × time (baseline, post 1, and post 2) ANOVA was used to test the hypothesized exercise-induced improvements in all outcomes. Statistically significant condition-time interactions were observed for vigor (P < 0.001), amphetamine (P < 0.001), motivation (P = 0.027), and Profile of Mood States depression (P = 0.027), fatigue (P = 0.030), and confusion (P = 0.046) scales. No significant interaction effects were observed for leg hyperactivity, simple reaction time, or vigilance task performance (accuracy, errors, or reaction time). In young men reporting elevated symptoms of ADHD, a 20-min bout of moderate-intensity cycle exercise transiently enhances motivation for cognitive tasks, increases feelings of energy, and reduces feelings of confusion, fatigue, and depression, but this has no effect on the behavioral measures of attention or hyperactivity used.

Beat-by-beat stroke volume assessment by pulsed Doppler in upright and supine exercise

NASA Technical Reports Server (NTRS)

Loeppky, J. A.; Greene, E. R.; Hoekenga, D. E.; Caprihan, A.; Luft, U. C.

1981-01-01

The instantaneous stroke volume (SV) and cardiac output (Q) in eight male subjects during steady-state supine (S) and upright (U) exercises at 300 kpm/min is assessed by a 3.0-MHz pulsed Doppler echocardiograph. The mean transients in heart rate (HR), SV, and Q for each posture were determined and the center-line blood velocities obtained in the ascending aorta. Results show that the mean supine values for SV and Q at rest and exercise were 111 ml and 6.4 l/min and 112 ml and 9.7 l/min, respectively. The corresponding results for U were 76 ml and 5.6 l/min and 92 ml and 8.4 l/min, respectively. The values compare favorably with previous studies utilizing invasive procedures. The transient response of Q following the onset of exercise in U was about twice as fast as in S because of the rapid and almost immediate upsurge in SV. The faster rise in aortic flow in U with exercise represented and additional volume (184 ml) of blood passing through the aorta compared with S in the first 20 exercises. It is suggested that the rapid mobilization of pooled venous blood from the leg veins during U was responsible for the increased blood flow.

Transient cutaneous vasodilatation and hypotension after drinking in dehydrated and exercising men

PubMed Central

Kamijo, Yoshi-Ichiro; Okumoto, Tadashi; Takeno, Yoshiaki; Okazaki, Kazunobu; Inaki, Mitsuharu; Masuki, Shizue; Nose, Hiroshi

2005-01-01

We examined whether oropharyngeal stimulation by drinking released the dehydration-induced suppression of cutaneous vasodilatation and decreased mean arterial pressure (MAP) in exercising subjects, and assessed the effects of hypovolaemia or hyperosmolality alone on these responses. Seven young males underwent four hydration conditions. These were two normal plasma volume (PV) trials: normal plasma osmolality (Posmol, control trial) and hyperosmolality (ΔPosmol = +11 mosmol (kg H2O)−1); and two low PV trials: isosmolality (ΔPV = −310 ml) and hyperosmolality (ΔPV = −345 ml; ΔPosmol = +9 mosmol (kg H2O)−1), attained by combined treatment with furosemide (frusemide), hypertonic saline and/or 24 h water restriction. In each trial, the subjects exercised at 60% peak aerobic power for ∼50 min at 30°C atmospheric temperature and 50% relative humidity. When oesophageal temperature (Toes) reached a plateau after ∼30 min of exercise, the subjects drank 200 ml water at 37.5°C within a minute. Before drinking, forearm vascular conductance (FVC), calculated as forearm blood flow divided by MAP, was lowered by 20–40% in hypovolaemia, hyperosmolality, or both, compared with that in the control trial, despite increased Toes. After drinking, FVC increased by ∼20% compared with that before drinking (P < 0.05) in both hyperosmotic trials, but it was greater in normovolaemia than in hypovolaemia (P < 0.05). However, no increases occurred in either isosmotic trial. MAP fell by 4–8 mmHg in both hyperosmotic trials (P < 0.05) after drinking, but more rapidly in normovolaemia than in hypovolaemia. PV and Posmol did not change during this period. Thus, oropharyngeal stimulation by drinking released the dehydration-induced suppression of cutaneous vasodilatation and reduced MAP during exercise, and this was accelerated when PV was restored. PMID:16123108

Exercise Increases 24-h Fat Oxidation Only When It Is Performed Before Breakfast

PubMed Central

Iwayama, Kaito; Kurihara, Reiko; Nabekura, Yoshiharu; Kawabuchi, Ryosuke; Park, Insung; Kobayashi, Masashi; Ogata, Hitomi; Kayaba, Momoko; Satoh, Makoto; Tokuyama, Kumpei

2015-01-01

Background As part of the growing lifestyle diversity in modern society, there is wide variation in the time of day individuals choose to exercise. Recent surveys in the US and Japan have reported that on weekdays, more people exercise in the evening, with fewer individuals exercising in the morning or afternoon. Exercise performed in the post-prandial state has little effect on accumulated fat oxidation over 24 h (24-h fat oxidation) when energy intake is matched to energy expenditure (energy-balanced condition). The present study explored the possibility that exercise increases 24-h fat oxidation only when performed in a post-absorptive state, i.e. before breakfast. Methods Indirect calorimetry using a metabolic chamber was performed in 10 young, non-obese men over 24 h. Subjects remained sedentary (control) or performed 60-min exercise before breakfast (morning), after lunch (afternoon), or after dinner (evening) at 50% of VO2max. All trials were designed to be energy balanced over 24 h. Time course of energy and substrate balance relative to the start of calorimetry were estimated from the differences between input (meal consumption) and output (oxidation). Findings Fat oxidation over 24 h was increased only when exercise was performed before breakfast (control, 456 ± 61; morning, 717 ± 64; afternoon, 446 ± 57; and evening, 432 ± 44 kcal/day). Fat oxidation over 24 h was negatively correlated with the magnitude of the transient deficit in energy and carbohydrate. Interpretation Under energy-balanced conditions, 24-h fat oxidation was increased by exercise only when performed before breakfast. Transient carbohydrate deficits, i.e., glycogen depletion, observed after morning exercise may have contributed to increased 24-h fat oxidation. PMID:26844280

The impact of intermittent exercise in a hypoxic environment on redox status and cardiac troponin release in the serum of well-trained marathon runners.

PubMed

Li, Feifei; Nie, Jinlei; Lu, Yifan; Tong, Tom Kwok Keung; Yi, Longyan; Yan, Huiping; Fu, Frank Hoo Kin; Ma, Shengxia

2016-10-01

To investigate the effects of hypoxic training on redox status and cardiac troponin (cTn) release after intermittent exercise. Nine well-trained male marathon runners (age, 21.7 ± 2.3 year; body mass, 64.7 ± 4.8 kg; height, 177.9 ± 3.8 cm; and VO2max, 64.3 ± 6.7 ml kg(-1) min(-1)) completed intermittent exercise under normoxic [trial N; fraction of inspiration oxygen (FIO2), 21.0 %] and hypoxic (trial H; FIO2, 14.4 %) conditions in random order. Each bout of intermittent exercise included hard run (16.2 ± 0.8 km h(-1)) at 90 % VO2max for 2 min followed by easy run (9.0 ± 0.4 km h(-1)) at 50 % VO2max for 2 min and 23 bouts in 92 min totally. Malondialdehyde, reduced glutathione (GSH), superoxide dismutase, an estimate of total antioxidant capacity (T-AOC), high-sensitivity cardiac troponin T (hs-cTnT), and cardiac troponin I (cTnI) were measured before, immediately after (0 h), and 2, 4, and 24 h after the completion of trials N and H. GSH was increased immediately after trial N. T-AOC was lower 4 h after trial H than trial N. Hs-cTnT was elevated from 0 to 4 h and returned to baseline 24 h after both trials. CTnI was increased after trial H; peaked at 2-4 h and returned to below the detection by 24 h. The overall redox status was balanced under normoxic conditions, and exercise-induced cTn release did not deviate. However, the protective effects of antioxidant were weaker in the hypoxic state than normoxic, and the stress on the myocardium induced by intermittent exercise was transiently aggravated.

Systems-level computational modeling demonstrates fuel selection switching in high capacity running and low capacity running rats

PubMed Central

Qi, Nathan R.

2018-01-01

High capacity and low capacity running rats, HCR and LCR respectively, have been bred to represent two extremes of running endurance and have recently demonstrated disparities in fuel usage during transient aerobic exercise. HCR rats can maintain fatty acid (FA) utilization throughout the course of transient aerobic exercise whereas LCR rats rely predominantly on glucose utilization. We hypothesized that the difference between HCR and LCR fuel utilization could be explained by a difference in mitochondrial density. To test this hypothesis and to investigate mechanisms of fuel selection, we used a constraint-based kinetic analysis of whole-body metabolism to analyze transient exercise data from these rats. Our model analysis used a thermodynamically constrained kinetic framework that accounts for glycolysis, the TCA cycle, and mitochondrial FA transport and oxidation. The model can effectively match the observed relative rates of oxidation of glucose versus FA, as a function of ATP demand. In searching for the minimal differences required to explain metabolic function in HCR versus LCR rats, it was determined that the whole-body metabolic phenotype of LCR, compared to the HCR, could be explained by a ~50% reduction in total mitochondrial activity with an additional 5-fold reduction in mitochondrial FA transport activity. Finally, we postulate that over sustained periods of exercise that LCR can partly overcome the initial deficit in FA catabolic activity by upregulating FA transport and/or oxidation processes. PMID:29474500

Exercise-induced hand tremor: a possible test for beta 2-adrenoceptor selectivity in man?

PubMed Central

Abila, B; Wilson, J F; Marshall, R W; Richens, A

1986-01-01

The effects of intravenous doses of propranolol, sotalol, timolol, atenolol and placebo on exercise-induced tachycardia and exercise-induced increases in hand tremor were assessed in four healthy volunteers. All active drugs produced significant reductions in exercise-induced tachycardia. Exercise caused consistent significant increases in hand tremor which were blocked by the three non-cardioselective drugs but not by atenolol or placebo. The blockade of exercise-induced hand tremor is suggested as a possible test for the assessment of the selectivity of beta-adrenoceptor blockade in man. PMID:2874824

Exercise induces autophagy in peripheral tissues and in the brain.

PubMed

He, Congcong; Sumpter, Rhea; Levine, Beth

2012-10-01

We recently identified physical exercise as a newly defined inducer of autophagy in vivo. Exercise induced autophagy in multiple organs involved in metabolic regulation, such as muscle, liver, pancreas and adipose tissue. To study the physiological role of exercise-induced autophagy, we generated mice with a knock-in nonphosphorylatable mutation in BCL2 (Thr69Ala, Ser70Ala and Ser84Ala) (BCL2 AAA) that are defective in exercise- and starvation-induced autophagy but not in basal autophagy. We found that BCL2 AAA mice could not run on a treadmill as long as wild-type mice, and did not undergo exercise-mediated increases in skeletal glucose muscle uptake. Unlike wild-type mice, the BCL2 AAA mice failed to reverse high-fat diet-induced glucose intolerance after 8 weeks of exercise training, possibly due to defects in signaling pathways that regulate muscle glucose uptake and metabolism during exercise. Together, these findings suggested a hitherto unknown important role of autophagy in mediating exercise-induced metabolic benefits. In the present addendum, we show that treadmill exercise also induces autophagy in the cerebral cortex of adult mice. This observation raises the intriguing question of whether autophagy may in part mediate the beneficial effects of exercise in neurodegeneration, adult neurogenesis and improved cognitive function.

Medical psychology in exercise and sport.

PubMed

Dishman, R K

1985-01-01

Several psychological outcomes that accompany acute and chronic exercise have medical significance. Transient reductions in somatic tension and subjective anxiety appear most reliable. Symptom abatement in moderate depression can occur with chronic exercise in a manner comparable to psychotherapy and may offer a better prognosis in some instances. Other cognitive, behavioral, and perceptual events associated with exercise may assist in managing mental health, and exercise has been successfully used as a therapeutic adjunct in a variety of psychiatric disorders. Regular exercise may also complement treatments designed to manage aspects of coronary-prone behavior and psychoendocrine responsivity to mental stress. The lack of strict experimental control or effective placebo contrasts in most exercise studies precludes a convincing argument that exercise causes the psychological outcomes observed. Rather, expectancy of benefits, generalized treatment or attention effects, social reinforcement, and past history or selection bias represent likely alternatives. These competing explanations do not discount, however, that many individuals benefit in a clinically significant way. Exercise offers a low-cost alternative or adjunct with side effects that appear largely health-related. Although the effective psychological dosage or modality has not been quantified, current physiologic guidelines of the American College of Sports Medicine (large muscle rhythmic activity, for 20 to 60 minutes, 3 to 5 days per week at 60 to 80 per cent age-adjusted maximal heart rate), or a weekly caloric cost of 2000 kcal, should be effective with little medical risk. However, no evidence confirms that an increase in metabolic or psychoendocrine tolerance to exercise is necessary or sufficient for psychological outcomes to occur. Although biologic adaptations are known to follow exercise training and subside with diminished activity, there is currently no objective evidence that habitual exercise leads to dependence. If exercise has use in managing subjective or somatic symptoms, these may return during periods of exercise abstinence. Moreover, despite popular hypotheses concerning endorphins and biogenic amines, no direct relationships have yet been shown between exercise-induced mood swings and peripheral biochemical events. A proportion of habitual runners have reported acute episodes of euphoria-like states during or following exercise, but this remains a subjective and unpredictable event that may be related to psychophysiologic relaxation or acute changes in self-esteem.(ABSTRACT TRUNCATED AT 400 WORDS)

Exercise-induced changes in mitral regurgitation in patients with prior myocardial infarction and left ventricular dysfunction: relation to mitral deformation and left ventricular function and shape.

PubMed

Giga, Vojislav; Ostojic, Miodrag; Vujisic-Tesic, Bosiljka; Djordjevic-Dikic, Ana; Stepanovic, Jelena; Beleslin, Branko; Petrovic, Milan; Nedeljkovic, Milan; Nedeljkovic, Ivana; Milic, Natasa

2005-09-01

The aim of this study was to assess the relationship between exercise-induced changes in mitral regurgitation (MR) and echocardiographic characteristics of mitral deformation, global left ventricular (LV) function and shape at rest and after exercise. Forty consecutive patients with ischaemic MR due to prior myocardial infarction (MI), ejection fraction <45% in sinus rhythm underwent exercise-echocardiographic testing. Exercise-induced changes in effective regurgitant orifice (ERO) were compared with baseline and exercise-induced changes in mitral deformation and global LV function and shape. There was significant correlation between exercise-induced changes in ERO and changes in coaptation distance (r=0.80, P<0.0001), tenting area (r=0.79, P<0.0001) and mitral annular diameter (r=0.65, P<0.0001), as well as in end-systolic sphericity index (r=-0.50, P=0.001, respectively), and wall motion score index (r=0.44, P=0.004). In contrast, exercise-induced changes in ERO were not related to the echocardiographic features at rest. By stepwise multiple regression model, the exercise-induced changes in mitral deformation were found to independently correlate with exercise-induced changes in ERO (generalized r(2)=0.80, P<0.0001). Exercise-induced changes in severity of ischaemic MR in patients with LV dysfunction due to prior MI were independently related to changes in mitral deformation.

Evidence of direct cardiac damage following high-intensity exercise in chronic energy restriction: A case report and literature review.

PubMed

Baird, Marianne F; Grace, Fergal; Sculthorpe, Nicholas; Graham, Scott M; Fleming, Audrey; Baker, Julien S

2017-07-01

Following prolonged endurance events such as marathons, elevated levels of cardiospecific biomarkers are commonly reported. Although transiently raised levels are generally not considered to indicate clinical myocardial damage, comprehension of this phenomenon remains incomplete. The popularity of high-intensity interval training highlights a paucity of research measuring cardiac biomarker response to this type of exercise. This a posteriori case report discusses the elevation of cardiac troponins (cTn) associated with short interval, high-intensity exercise. In this case report, an apparently healthy 29-year-old recreationally active female presented clinically raised cardiac troponin I (cTnI) levels (>0.04 ng/mL), after performing high-intensity cycle ergometer sprints. As creatine kinase (CK) is expressed by multiple organs (e.g., skeletal muscle, brain, and myocardium), cTnI assays were performed to determine any changes in total serum CK levels not originating from skeletal muscle damage. A posteriori the individual's daily energy expenditure indicated chronically low-energy availability. Psychometric testing suggested that the individual scored positive for disordered eating, highly for fatigue levels, and low in mental health components. The current case report provides novel evidence of elevated cTnI occurring as a result of performing short duration, high intensity, cycle ergometer exercise in an individual with self-reported chronically depleted energy balance. A schematic to identify potentially "at risk" individuals is presented. Considering this as a case report, results cannot be generalized; however, the main findings suggest that individuals who habitually restrict their calorie intake below their bodies' daily energy requirements, may have elevated biomarkers of exercise induced myocardial stress from performing high-intensity exercise.

The effects of high-intensity exercise on neural responses to images of food.

PubMed

Crabtree, Daniel R; Chambers, Edward S; Hardwick, Robert M; Blannin, Andrew K

2014-02-01

Acute bouts of high-intensity exercise modulate peripheral appetite regulating hormones to transiently suppress hunger. However, the effects of physical activity on central appetite regulation have yet to be fully investigated. We used functional magnetic resonance imaging (fMRI) to compare neural responses to visual food stimuli after intense exercise and rest. Fifteen lean healthy men [mean ± SD age: 22.5 ± 3.1 y; mean ± SD body mass index (in kg/m(2)): 24.2 ± 2.4] completed two 60-min trials-exercise (EX; running at ∼70% maximum aerobic capacity) and a resting control trial (REST)-in a counterbalanced order. After each trial, an fMRI assessment was completed in which images of high- and low-calorie foods were viewed. EX significantly suppressed subjective appetite responses while increasing thirst and core-body temperature. Furthermore, EX significantly suppressed ghrelin concentrations and significantly enhanced peptide YY release. Neural responses to images of high-calorie foods significantly increased dorsolateral prefrontal cortex activation and suppressed orbitofrontal cortex (OFC) and hippocampus activation after EX compared with REST. After EX, low-calorie food images increased insula and putamen activation and reduced OFC activation compared with REST. Furthermore, left pallidum activity was significantly elevated after EX when low-calorie images were viewed and was suppressed when high-calorie images were viewed, and these responses correlated significantly with thirst. Exercise increases neural responses in reward-related regions of the brain in response to images of low-calorie foods and suppresses activation during the viewing of high-calorie foods. These central responses are associated with exercise-induced changes in peripheral signals related to appetite-regulation and hydration status. This trial was registered at www.clinicaltrials.gov as NCT01926431.

HIF-1α and HIF-2α induce angiogenesis and improve muscle energy recovery.

PubMed

Niemi, Henna; Honkonen, Krista; Korpisalo, Petra; Huusko, Jenni; Kansanen, Emilia; Merentie, Mari; Rissanen, Tuomas T; André, Helder; Pereira, Teresa; Poellinger, Lorenz; Alitalo, Kari; Ylä-Herttuala, Seppo

2014-10-01

Cardiovascular patients suffer from reduced blood flow leading to ischaemia and impaired tissue metabolism. Unfortunately, an increasing group of elderly patients cannot be treated with current revascularization methods. Thus, new treatment strategies are urgently needed. Hypoxia-inducible factors (HIFs) upregulate the expression of angiogenic mediators together with genes involved in energy metabolism and recovery of ischaemic tissues. Especially, HIF-2α is a novel factor, and only limited information is available about its therapeutic potential. Gene transfers with adenoviral HIF-1α and HIF-2α were performed into the mouse heart and rabbit ischaemic hindlimbs. Angiogenesis was evaluated by histology. Left ventricle function was analysed with echocardiography. Perfusion in rabbit skeletal muscles and energy recovery after electrical stimulation-induced exercise were measured with ultrasound and (31)P-magnetic resonance spectroscopy ((31)P-MRS), respectively. HIF-1α and HIF-2α gene transfers increased capillary size up to fivefold in myocardium and ischaemic skeletal muscles. Perfusion in skeletal muscles was increased by fourfold without oedema. Especially, AdHIF-1α enhanced the recovery of ischaemic muscles from electrical stimulation-induced energy depletion. Special characteristic of HIF-2α gene transfer was a strong capillary growth in muscle connective tissue and that HIF-2α gene transfer maintained left ventricle function. We conclude that both AdHIF-1α and AdHIF-2α gene transfers induced beneficial angiogenesis in vivo. Transient moderate increases in angiogenesis improved energy recovery after exercise in ischaemic muscles. This study shows for the first time that a moderate increase in angiogenesis is enough to improve tissue energy metabolism, which is potentially a very useful feature for cardiovascular gene therapy. © 2014 Stichting European Society for Clinical Investigation Journal Foundation.

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

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.

Increased Temperature and Protein Oxidation Signal HSP72 mRNA and Protein Accumulation in the In Vivo Exercised Rat Heart

PubMed Central

Staib, Jessica L.; Tümer, Nihal; Powers, Scott K.

2010-01-01

Myocardial heat shock protein 72 (HSP72) expression, mediated by its transcription factor heat shock factor 1 (HSF1), increases following exercise. However, the up-stream stimuli governing exercise-induced HSF1 activation and subsequent HSP72 gene expression in the whole animal remain unclear. Exercise-induced increases in body temperature may promote myocardial radical production leading to protein oxidation. Conceivably, myocardial protein oxidation during exercise may serve as an important signal promoting nuclear HSF1 migration and activation of HSP72 expression. Therefore, these experiments tested the hypothesis that preventing exercise-induced increases in body temperature attenuates cardiac protein oxidation, diminishes HSF1 activation and decreases HSP72 expression in vivo. To test this hypothesis, in vivo exercise-induced body temperature was manipulated by exercising male rats in either cold (4°C) or warm (22°C) ambient conditions. Warm exercise increased both body temperature (+ 3°C) and myocardial protein oxidation whereas these changes were attenuated by cold exercise. Interestingly, exercise in both conditions did not significantly increase myocardial nuclear localized phosphorylated HSF1. Nonetheless, warm exercise elevated left-ventricular HSP72 mRNA by 9-fold and increased myocardial HSP72 protein levels by 3-fold compared to cold-exercised animals. Collectively, these data indicate that elevated body temperature and myocardial protein oxidation promoted exercise-induced cardiac HSP72 mRNA expression and protein accumulation following in vivo exercise. However, these results suggest that exercise-induced myocardial HSP72 protein accumulation is not a result of nuclear-localized, phosphorylated HSF1 indicating that other transcriptional or posttranscriptional regulatory mechanisms are involved in exercise-induced HSP72 expression. PMID:18931043

Exercise and Asthma

MedlinePlus

... Treatments ▸ Library ▸ Asthma Library ▸ Exercise and Asthma Share | Exercise and Asthma This article has been reviewed by Thanai Pongdee, MD, FAAAAI Exercise-induced bronchoconstriction (EIB) , also called exercise-induced asthma, ...

Trauma-induced systemic inflammatory response versus exercise-induced immunomodulatory effects.

PubMed

Fehrenbach, Elvira; Schneider, Marion E

2006-01-01

Accidental trauma and heavy endurance exercise, both induce a kind of systemic inflammatory response, also called systemic inflammatory response syndrome (SIRS). Exercise-related SIRS is conditioned by hyperthermia and concomitant heat shock responses, whereas trauma-induced SIRS manifests concomitantly with tissue necrosis and immune activation, secondarily followed by fever. Inflammatory cytokines are common denominators in both trauma and exercise, although there are marked quantitative differences. Different anti-inflammatory cytokines may be involved in the control of inflammation in trauma- and exercise-induced stress. Exercise leads to a balanced equilibrium between inflammatory and anti-inflammatory responses. Intermittent states of rest, as well as anti-oxidant capacity, are lacking or minor in trauma but are high in exercising individuals. Regular training may enhance immune competence, whereas trauma-induced SIRS often paves the way for infectious complications, such as sepsis.

Food-Dependent, Exercise-Induced Anaphylaxis: Diagnosis and Management in the Outpatient Setting.

PubMed

Feldweg, Anna M

Food-dependent, exercise-induced anaphylaxis is a disorder in which anaphylaxis develops most predictably during exercise, when exercise takes place within a few hours of ingesting a specific food. IgE to that food should be demonstrable. It is the combination of the food and exercise that precipitates attacks, whereas the food and exercise are each tolerated independently. Recently, it was demonstrated that exercise is not essential for the development of symptoms, and that if enough of the culprit food is ingested, often with additional augmentation factors, such as alcohol or acetylsalicylic acid, symptoms can be induced at rest in the challenge setting. Thus, food-dependent, exercise-induced anaphylaxis appears to be more correctly characterized as a food allergy syndrome in which symptoms develop only in the presence of various augmentation factors, with exercise being the primary one. However, additional factors are not usually present when the patient exercises normally, so ongoing investigation is needed into the physiologic and cellular changes that occur during exercise to facilitate food-induced anaphylaxis. Copyright © 2016 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

Exercise-induced nausea and vomiting: another sign and symptom of pheochromocytoma and paraganglioma.

PubMed

King, Kathryn S; Darmani, Nissar A; Hughes, Marybeth S; Adams, Karen T; Pacak, Karel

2010-06-01

A cohort of nine patients, mostly young adults, presented with a new sign/symptom of pheochromocytoma/paraganglioma: exercise-induced nausea and vomiting. The aims of this article are to introduce this sign/symptom and offer a possible hypothesis for the observation. Following a 2000 report from a paraganglioma patient experiencing exercise-induced nausea and vomiting, we began asking patients about instances of nausea and vomiting with exercise. A total of nine patients, 4.4% of our pheochromocytoma/paraganglioma population, presented with reports of exercise-induced nausea and vomiting, initially with moderate-to-intense levels of exercise, at the first presentation of their disease. All of these patients reported a cessation of exercise-induced nausea and vomiting following the removal of their primary tumor. Two patients with metastatic disease to the lungs reported a recurrence of exercise-induced nausea and vomiting. The majority of patients studied were young adults with mean onset age of 19.4 years (range of 9-51 years) and the mean age of diagnosis being 24.1 years (range of 11-53 years). Exercise-induced nausea and vomiting should be considered a sign/symptom of pheochromocytoma/paraganglioma and should be addressed in the clinical evaluation of these patients, especially in young adults. Whether exercise-induced elevated catecholamine levels could account for the induced nausea and vomiting via activation of adrenergic receptors in the area postrema remains to be established.

Mental stress-induced ischemia in patients with coronary artery disease: echocardiographic characteristics and relation to exercise-induced ischemia.

PubMed

Stepanovic, Jelena; Ostojic, Miodrag; Beleslin, Branko; Vukovic, Olivera; Djordjevic-Dikic, Ana; Dikic, Ana Djordjevic; Giga, Vojislav; Nedeljkovic, Ivana; Nedeljkovic, Milan; Stojkovic, Sinisa; Vukcevic, Vladan; Dobric, Milan; Petrasinovic, Zorica; Marinkovic, Jelena; Lecic-Tosevski, Dusica

2012-09-01

The aims of this study were to investigate the incidence and parameters associated with myocardial ischemia during mental stress (MS) as measured by echocardiography and to evaluate the relation between MS-induced and exercise-induced myocardial ischemia. Study participants were 79 patients (63 men; mean [M] [standard deviation {SD}] age = 52 [8] years) with angiographically confirmed coronary artery disease and previous positive exercise test result. The MS protocol consisted of mental arithmetic and anger recall task. The patients performed a treadmill exercise test 15 to 20 minutes after the MS task. Data of post-MS exercise were compared with previous exercise stress test results. The frequency of echocardiographic abnormalities was 35% in response to the mental arithmetic task, compared with 61% with anger recall and 96% with exercise (p < .001, exercise versus MS). Electrocardiogram abnormalities and chest pain were substantially less common during MS than were echocardiographic abnormalities. Independent predictors of MS-induced myocardial ischemia were: wall motion score index at rest (p = .02), peak systolic blood pressure (p = .005), and increase in rate-pressure product (p = .004) during MS. The duration of exercise stress test was significantly shorter (p < .001) when MS preceded the exercise and in the case of earlier exercise (M [SD] = 4.4 [1.9] versus 6.7 [2.2] minutes for patients positive on MS and 5.7 [1.9] versus 8.0 [2.3] minutes for patients negative on MS). Echocardiography can be successfully used to document myocardial ischemia induced by MS. MS-induced ischemia was associated with an increase in hemodynamic parameters during MS and worse function of the left ventricle. MS may shorten the duration of subsequent exercise stress testing and can potentiate exercise-induced ischemia in susceptible patients with coronary artery disease.

Exercise induced asthma and endogenous opioids.

PubMed Central

Gaillard, R C; Bachman, M; Rochat, T; Egger, D; de Haller, R; Junod, A F

1986-01-01

Concentrations of endogenous opioid peptides in the plasma are increased during exercise and these substances have been implicated in the pathogenesis of asthma induced by chloropropramide and alcohol in diabetic patients. This work was undertaken to determine whether exercise induced asthma might be mediated by endogenous opioids. Plasma beta endorphin, met-enkephalin, and adrenocorticotrophic hormone (ACTH) concentrations were measured in five asthmatic patients and five normal volunteers breathing cold air during exercise. In four of the patients the effect of an infusion of naloxone on FEV1 was also measured during exercise induced asthma. Exercise produced acute bronchoconstriction in all asthmatics, characterised by a fall in FEV1; whereas no change occurred in normal subjects. There was no difference in plasma met-enkephalin, beta endorphin, and ACTH concentration between the two groups. Infusion of naloxone neither prevented nor worsened exercise induced asthma. These data suggest that endogenous opioids probably do not play a part in the development of exercise induced asthma. PMID:2944240

Modeling rate sensitivity of exercise transient responses to limb motion.

PubMed

Yamashiro, Stanley M; Kato, Takahide

2014-10-01

Transient responses of ventilation (V̇e) to limb motion can exhibit predictive characteristics. In response to a change in limb motion, a rapid change in V̇e is commonly observed with characteristics different than during a change in workload. This rapid change has been attributed to a feed-forward or adaptive response. Rate sensitivity was explored as a specific hypothesis to explain predictive V̇e responses to limb motion. A simple model assuming an additive feed-forward summation of V̇e proportional to the rate of change of limb motion was studied. This model was able to successfully account for the adaptive phase correction observed during human sinusoidal changes in limb motion. Adaptation of rate sensitivity might also explain the reduction of the fast component of V̇e responses previously reported following sudden exercise termination. Adaptation of the fast component of V̇e response could occur by reduction of rate sensitivity. Rate sensitivity of limb motion was predicted by the model to reduce the phase delay between limb motion and V̇e response without changing the steady-state response to exercise load. In this way, V̇e can respond more quickly to an exercise change without interfering with overall feedback control. The asymmetry between responses to an incremental and decremental ramp change in exercise can also be accounted for by the proposed model. Rate sensitivity leads to predicted behavior, which resembles responses observed in exercise tied to expiratory reserve volume. Copyright © 2014 the American Physiological Society.

Interactive processes link the multiple symptoms of fatigue in sport competition.

PubMed

Knicker, Axel J; Renshaw, Ian; Oldham, Anthony R H; Cairns, Simeon P

2011-04-01

Muscle physiologists often describe fatigue simply as a decline of muscle force and infer this causes an athlete to slow down. In contrast, exercise scientists describe fatigue during sport competition more holistically as an exercise-induced impairment of performance. The aim of this review is to reconcile the different views by evaluating the many performance symptoms/measures and mechanisms of fatigue. We describe how fatigue is assessed with muscle, exercise or competition performance measures. Muscle performance (single muscle test measures) declines due to peripheral fatigue (reduced muscle cell force) and/or central fatigue (reduced motor drive from the CNS). Peak muscle force seldom falls by >30% during sport but is often exacerbated during electrical stimulation and laboratory exercise tasks. Exercise performance (whole-body exercise test measures) reveals impaired physical/technical abilities and subjective fatigue sensations. Exercise intensity is initially sustained by recruitment of new motor units and help from synergistic muscles before it declines. Technique/motor skill execution deviates as exercise proceeds to maintain outcomes before they deteriorate, e.g. reduced accuracy or velocity. The sensation of fatigue incorporates an elevated rating of perceived exertion (RPE) during submaximal tasks, due to a combination of peripheral and higher CNS inputs. Competition performance (sport symptoms) is affected more by decision-making and psychological aspects, since there are opponents and a greater importance on the result. Laboratory based decision making is generally faster or unimpaired. Motivation, self-efficacy and anxiety can change during exercise to modify RPE and, hence, alter physical performance. Symptoms of fatigue during racing, team-game or racquet sports are largely anecdotal, but sometimes assessed with time-motion analysis. Fatigue during brief all-out racing is described biomechanically as a decline of peak velocity, along with altered kinematic components. Longer sport events involve pacing strategies, central and peripheral fatigue contributions and elevated RPE. During match play, the work rate can decline late in a match (or tournament) and/or transiently after intense exercise bursts. Repeated sprint ability, agility and leg strength become slightly impaired. Technique outcomes, such as velocity and accuracy for throwing, passing, hitting and kicking, can deteriorate. Physical and subjective changes are both less severe in real rather than simulated sport activities. Little objective evidence exists to support exercise-induced mental lapses during sport. A model depicting mind-body interactions during sport competition shows that the RPE centre-motor cortex-working muscle sequence drives overall performance levels and, hence, fatigue symptoms. The sporting outputs from this sequence can be modulated by interactions with muscle afferent and circulatory feedback, psychological and decision-making inputs. Importantly, compensatory processes exist at many levels to protect against performance decrements. Small changes of putative fatigue factors can also be protective. We show that individual fatigue factors including diminished carbohydrate availability, elevated serotonin, hypoxia, acidosis, hyperkalaemia, hyperthermia, dehydration and reactive oxygen species, each contribute to several fatigue symptoms. Thus, multiple symptoms of fatigue can occur simultaneously and the underlying mechanisms overlap and interact. Based on this understanding, we reinforce the proposal that fatigue is best described globally as an exercise-induced decline of performance as this is inclusive of all viewpoints. © 2011 Adis Data Information BV. All rights reserved.

Susceptibility of materials processing experiments to low-level accelerations

NASA Technical Reports Server (NTRS)

Naumann, R. J.

1981-01-01

The types of material processing experiments being considered for shuttle can be grouped into four categories: (1) contained solidification experiment; (2) quasicontainerless experiments; (3) containerless experiments; and (4) fluids experiments. Low level steady acceleration, compensated and uncompensated transient accelerations, and rotation induced flow factors that must be considered in the acceleration environment of a space vehicle whose importance depends on the type of experiment being performed. Some control of these factors may be exercised by the location and orientation of the experiment relative to shuttle and by the orbit vehicle attitude chosen for mission. The effects of the various residual accelerations can have serious consequence to the control of the experiment and must be factored into the design and operation of the apparatus.

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.

Sprint performance under heat stress: A review.

PubMed

Girard, O; Brocherie, F; Bishop, D J

2015-06-01

Training and competition in major track-and-field events, and for many team or racquet sports, often require the completion of maximal sprints in hot (>30 °C) ambient conditions. Enhanced short-term (<30 s) power output or single-sprint performance, resulting from transient heat exposure (muscle temperature rise), can be attributed to improved muscle contractility. Under heat stress, elevations in skin/core temperatures are associated with increased cardiovascular and metabolic loads in addition to decreasing voluntary muscle activation; there is also compelling evidence to suggest that large performance decrements occur when repeated-sprint exercise (consisting of brief recovery periods between sprints, usually <60 s) is performed in hot compared with cool conditions. Conversely, poorer intermittent-sprint performance (recovery periods long enough to allow near complete recovery, usually 60-300 s) in hotter conditions is solely observed when exercise induces marked hyperthermia (core temperature >39 °C). Here we also discuss strategies (heat acclimatization, precooling, hydration strategies) employed by "sprint" athletes to mitigate the negative influence of higher environmental temperatures. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Exercise-induced BCL2-regulated autophagy is required for muscle glucose homeostasis.

PubMed

He, Congcong; Bassik, Michael C; Moresi, Viviana; Sun, Kai; Wei, Yongjie; Zou, Zhongju; An, Zhenyi; Loh, Joy; Fisher, Jill; Sun, Qihua; Korsmeyer, Stanley; Packer, Milton; May, Herman I; Hill, Joseph A; Virgin, Herbert W; Gilpin, Christopher; Xiao, Guanghua; Bassel-Duby, Rhonda; Scherer, Philipp E; Levine, Beth

2012-01-18

Exercise has beneficial effects on human health, including protection against metabolic disorders such as diabetes. However, the cellular mechanisms underlying these effects are incompletely understood. The lysosomal degradation pathway, autophagy, is an intracellular recycling system that functions during basal conditions in organelle and protein quality control. During stress, increased levels of autophagy permit cells to adapt to changing nutritional and energy demands through protein catabolism. Moreover, in animal models, autophagy protects against diseases such as cancer, neurodegenerative disorders, infections, inflammatory diseases, ageing and insulin resistance. Here we show that acute exercise induces autophagy in skeletal and cardiac muscle of fed mice. To investigate the role of exercise-mediated autophagy in vivo, we generated mutant mice that show normal levels of basal autophagy but are deficient in stimulus (exercise- or starvation)-induced autophagy. These mice (termed BCL2 AAA mice) contain knock-in mutations in BCL2 phosphorylation sites (Thr69Ala, Ser70Ala and Ser84Ala) that prevent stimulus-induced disruption of the BCL2-beclin-1 complex and autophagy activation. BCL2 AAA mice show decreased endurance and altered glucose metabolism during acute exercise, as well as impaired chronic exercise-mediated protection against high-fat-diet-induced glucose intolerance. Thus, exercise induces autophagy, BCL2 is a crucial regulator of exercise- (and starvation)-induced autophagy in vivo, and autophagy induction may contribute to the beneficial metabolic effects of exercise.

Exercise-induced neuroplasticity in human Parkinson's disease: What is the evidence telling us?

PubMed

Hirsch, Mark A; Iyer, Sanjay S; Sanjak, Mohammed

2016-01-01

While animal models of exercise and PD have pushed the field forward, few studies have addressed exercise-induced neuroplasticity in human PD. As a first step toward promoting greater international collaboration on exercise-induced neuroplasticity in human PD, we present data on 8 human PD studies (published between 2008 and 2015) with 144 adults with PD of varying disease severity (Hoehn and Yahr stage 1 to stage 3), using various experimental (e.g., randomized controlled trial) and quasi-experimental designs on the effects of cognitive and physical activity on brain structure or function in PD. We focus on plasticity mechanisms of intervention-induced increases in maximal corticomotor excitability, exercise-induced changes in voxel-based gray matter volume changes and increases in exercise-induced serum levels of brain derived neurotrophic factor (BDNF). Finally, we provide a future perspective for promoting international, collaborative research on exercise-induced neuroplasticity in human PD. An emerging body of evidence suggests exercise triggers several plasticity related events in the human PD brain including corticomotor excitation, increases and decreases in gray matter volume and changes in BDNF levels. Copyright © 2015 Elsevier Ltd. All rights reserved.

Transient myocardial tissue and function changes during a marathon in less fit marathon runners.

PubMed

Gaudreault, Valerie; Tizon-Marcos, Helena; Poirier, Paul; Pibarot, Philippe; Gilbert, Philippe; Amyot, Marc; Rodés-Cabau, Josep; Després, Jean-Pierre; Bertrand, Olivier; Larose, Eric

2013-10-01

Although regular physical activity improves health, strenuous exercise might transiently increase cardiac risk. Training and fitness might provide protection. We prospectively studied 20 recreational marathon runners without known cardiovascular disease or symptoms: at peak training before, immediately after, and 3 months after a 42.2-km marathon. Changes in global/segmental myocardial function, edema, resting perfusion, and fibrosis were measured. At peak training, runners exercised 8.1 ± 2.3 hours and 62 ± 18 km per week with mean maximal oxygen consumption (VO2max) of 53.2 ± 8.3 mL/kg/min. In response to the marathon, global left ventricular and right ventricular ejection fraction decreased in half of the runners; these runners had poorer peak training distance, training time, and fitness level. Change in global left ventricular ejection fraction was associated with VO2max. Overall, 36% of segments developed edema, 53% decreased function, and 59% decreased perfusion. Significant agreement was observed between segment decreasing function, decreasing perfusion, and developing edema. Myocardial changes were reversible at 3 months. Completing a marathon leads to localized myocardial edema, diminished perfusion, and decreased function occurring more extensively in less trained and fit runners. Although reversible, these changes might contribute to the transient increase in cardiac risk reported during sustained vigorous exercise. Copyright © 2013 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.

Carbohydrate ingestion before and during soccer match play and blood glucose and lactate concentrations.

PubMed

Russell, Mark; Benton, David; Kingsley, Michael

2014-01-01

The ingestion of carbohydrate (CHO) before and during exercise and at halftime is commonly recommended to soccer players for maintaining blood glucose concentrations throughout match play. However, an exercise-induced rebound glycemic response has been observed in the early stages of the second half of simulated soccer-specific exercise when CHO-electrolyte beverages were consumed regularly. Therefore, the metabolic effects of CHO beverage consumption throughout soccer match play remain unclear. To investigate the blood glucose and blood lactate responses to CHOs ingested before and during soccer match play. Crossover study. Applied research study. Ten male outfield academy soccer players (age = 15.6 ± 0.2 years, height = 1.74 ± 0.02 m, mass = 65.3 ± 1.9 kg, estimated maximal oxygen consumption = 58.4 ± 0.8 mL·kg(-1)·min(-1)). Players received a 6% CHO-electrolyte solution or an electrolyte (placebo) solution 2 hours before kickoff, before each half (within 10 minutes), and every 15 minutes throughout exercise. Blood samples were obtained at rest, every 15 minutes during the match (first half: 0-15, 15-30, and 30-45 minutes; second half: 45-60, 60-75, and 75-90 minutes) and 10 minutes into the halftime break. Metabolic responses (blood glucose and blood lactate concentrations) and markers of exercise intensity (heart rate) were recorded. Supplementation influenced the blood glucose response to exercise (time × treatment interaction effect: P ≤ .05), such that glucose concentrations were higher at 30 to 45 minutes in the CHO than in the placebo condition. However, in the second half, blood glucose concentrations were similar between conditions because of transient reductions from peak values occurring in both trials at halftime. Blood lactate concentrations were elevated above those at rest in the first 15 minutes of exercise (time-of-sample effect: P < .001) and remained elevated throughout exercise. Supplementation did not influence the pattern of response (time × treatment interaction effect: P = .49). Ingestion of a 6% CHO-electrolyte beverage before and during soccer match play did not benefit blood glucose concentrations throughout the second half of exercise.

Exploring the Relationship between Exercise-Induced Arousal and Cognition Using Fractionated Response Time

ERIC Educational Resources Information Center

Chang, Yu-Kai; Etnier, Jennifer L.; Barella, Lisa A.

2009-01-01

Although a generally positive effect of acute exercise on cognitive performance has been demonstrated, the specific nature of the relationship between exercise-induced arousal and cognitive performance remains unclear. This study was designed to identify the relationship between exercise-induced arousal and cognitive performance for the central…

The role of phosphoinositide 3-kinase and phosphatidic acid in the regulation of mammalian target of rapamycin following eccentric contractions

PubMed Central

O’Neil, T K; Duffy, L R; Frey, J W; Hornberger, T A

2009-01-01

Resistance exercise induces a hypertrophic response in skeletal muscle and recent studies have begun to shed light on the molecular mechanisms involved in this process. For example, several studies indicate that signalling by the mammalian target of rapamycin (mTOR) is necessary for a hypertrophic response. Furthermore, resistance exercise has been proposed to activate mTOR signalling through an upstream pathway involving the phosphoinositide 3-kinase (PI3K) and protein kinase B (PKB); however, this hypothesis has not been thoroughly tested. To test this hypothesis, we first evaluated the temporal pattern of signalling through PI3K–PKB and mTOR following a bout of resistance exercise with eccentric contractions (EC). Our results indicated that the activation of signalling through PI3K–PKB is a transient event (<15 min), while the activation of mTOR is sustained for a long duration (>12 h). Furthermore, inhibition of PI3K–PKB activity did not prevent the activation of mTOR signalling by ECs, indicating that PI3K–PKB is not part of the upstream regulatory pathway. These observations led us to investigate an alternative pathway for the activation of mTOR signalling involving the synthesis of phosphatidic acid (PA) by phospholipase D (PLD). Our results demonstrate that ECs induce a sustained elevation in [PA] and inhibiting the synthesis of PA by PLD prevented the activation of mTOR. Furthermore, we determined that similar to ECs, PA activates mTOR signalling through a PI3K–PKB-independent mechanism. Combined, the results of this study indicate that the activation of mTOR following eccentric contractions occurs through a PI3K–PKB-independent mechanism that requires PLD and PA. PMID:19470781

[Exercise-induced oedema due to hormone-containing intrauterine device].

PubMed

Franssen, Laurens E; Bos, Willem-Jan W

2012-01-01

Oedema is a known adverse effect of the levonorgestrel-containing intrauterine device (Mirena IUD). However, exercise-induced oedema has not been described before. A 38-year-old woman presented with symptoms of diffuse, exercise-induced oedema and dyspnoea. Tests for heart failure and other causes of oedema showed no abnormalities. All symptoms resolved spontaneously after the patient initiated removal of the IUD. The pathophysiology of exercise-induced oedema is still poorly understood. When confronted with a patient with oedema (induced by exercise or other cause), the most common causes must first be excluded. If no explanation can be found, then the effects of medication must not be overlooked.

Exercise training and immune crosstalk in breast cancer microenvironment: exploring the paradigms of exercise-induced immune modulation and exercise-induced myokines.

PubMed

Goh, Jorming; Niksirat, Negin; Campbell, Kristin L

2014-01-01

Observational research suggests that exercise may reduce the risk of breast cancer and improve survival. One proposed mechanism for the protective effect of aerobic exercise related to cancer risk and outcomes, but has not been examined definitively, is the immune response to aerobic exercise. Two prevailing paradigms are proposed. The first considers the host immune response as modifiable by aerobic exercise training. This exercise-modulated immune-tumor crosstalk in the mammary microenvironment may alter the balance between tumor initiation and progression versus tumor suppression. The second paradigm considers the beneficial role of exercise-induced, skeletal muscle-derived cytokines, termed "myokines". These myokines exert endocrine-like effects on multiple organs, including the mammary glands. In this systematic review, we i) define the role of macrophages and T-cells in breast cancer initiation and progression; ii) address the two paradigms that support exercise-induced immunomodulation; iii) systematically assessed the literature for exercise intervention that assessed biomarkers relevant to both paradigms in human intervention trials of aerobic exercise training, in healthy women and women with breast cancer; iv) incorporated pre-clinical animal studies and non-RCTs for background discussion of putative mechanisms, through which aerobic exercise training modulates the immunological crosstalk, or the myokine-tumor interaction in the tumor microenvironment; and v) speculated on the potential biomarkers and mechanisms that define an exercise-induced, anti-tumor "signature", with a view toward developing relevant biomarkers for future aerobic exercise intervention trials.

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

Blood Viscosity Responses to Exercise and Conditioning in Women

DTIC Science & Technology

1983-10-20

cope with the dis- comfort of exercise induced by acidosis then becomes a major determinant of the duration of exercise . Physiology of Aerobic...long term strenuous activity an increased loss of red blood cells may occur. ’ This has been termed "sports anemia." Exercise - induced loss of red cells...may be significant factors in some cases. ’ ’ With improved training regimens and improvements in running shoes, exercise induced "sports anemia" is

Aerobic exercise modulates anticipatory reward processing via the μ-opioid receptor system.

PubMed

Saanijoki, Tiina; Nummenmaa, Lauri; Tuulari, Jetro J; Tuominen, Lauri; Arponen, Eveliina; Kalliokoski, Kari K; Hirvonen, Jussi

2018-06-08

Physical exercise modulates food reward and helps control body weight. The endogenous µ-opioid receptor (MOR) system is involved in rewarding aspects of both food and physical exercise, yet interaction between endogenous opioid release following exercise and anticipatory food reward remains unresolved. Here we tested whether exercise-induced opioid release correlates with increased anticipatory reward processing in humans. We scanned 24 healthy lean men after rest and after a 1 h session of aerobic exercise with positron emission tomography (PET) using MOR-selective radioligand [ 11 C]carfentanil. After both PET scans, the subjects underwent a functional magnetic resonance imaging (fMRI) experiment where they viewed pictures of palatable versus nonpalatable foods to trigger anticipatory food reward responses. Exercise-induced changes in MOR binding in key regions of reward circuit (amygdala, thalamus, ventral and dorsal striatum, and orbitofrontal and cingulate cortices) were used to predict the changes in anticipatory reward responses in fMRI. Exercise-induced changes in MOR binding correlated negatively with the exercise-induced changes in neural anticipatory food reward responses in orbitofrontal and cingulate cortices, insula, ventral striatum, amygdala, and thalamus: higher exercise-induced opioid release predicted higher brain responses to palatable versus nonpalatable foods. We conclude that MOR activation following exercise may contribute to the considerable interindividual variation in food craving and consumption after exercise, which might promote compensatory eating and compromise weight control. © 2018 Wiley Periodicals, Inc.

Exercise-mimetic AICAR transiently benefits brain function

PubMed Central

Guerrieri, Davide; van Praag, Henriette

2015-01-01

Exercise enhances learning and memory in animals and humans. The role of peripheral factors that may trigger the beneficial effects of running on brain function has been sparsely examined. In particular, it is unknown whether AMP-kinase (AMPK) activation in muscle can predict enhancement of brain plasticity. Here we compare the effects of running and administration of AMPK agonist 5-Aminoimidazole-4-carboxamide 1-β-D-ribofuranoside (AICAR, 500 mg/kg), for 3, 7 or 14 days in one-month-old male C57BL/6J mice, on muscle AMPK signaling. At the time-points where we observed equivalent running- and AICAR-induced muscle pAMPK levels (7 and 14 days), cell proliferation, synaptic plasticity and gene expression, as well as markers of oxidative stress and inflammation in the dentate gyrus (DG) of the hippocampus and lateral entorhinal cortex (LEC) were evaluated. At the 7-day time-point, both regimens increased new DG cell number and brain-derived neurotrophic factor (BDNF) protein levels. Furthermore, microarray analysis of DG and LEC tissue showed a remarkable overlap between running and AICAR in the regulation of neuronal, mitochondrial and metabolism related gene classes. Interestingly, while similar outcomes for both treatments were stable over time in muscle, in the brain an inversion occurred at fourteen days. The compound no longer increased DG cell proliferation or neurotrophin levels, and upregulated expression of apoptotic genes and inflammatory cytokine interleukin-1β. Thus, an exercise mimetic that produces changes in muscle consistent with those of exercise does not have the same sustainable positive effects on the brain, indicating that only running consistently benefits brain function. PMID:26286955

Exercise-mimetic AICAR transiently benefits brain function.

PubMed

Guerrieri, Davide; van Praag, Henriette

2015-07-30

Exercise enhances learning and memory in animals and humans. The role of peripheral factors that may trigger the beneficial effects of running on brain function has been sparsely examined. In particular, it is unknown whether AMP-kinase (AMPK) activation in muscle can predict enhancement of brain plasticity. Here we compare the effects of running and administration of AMPK agonist 5-Aminoimidazole-4-carboxamide 1-β-D-ribofuranoside (AICAR, 500 mg/kg), for 3, 7 or 14 days in one-month-old male C57BL/6J mice, on muscle AMPK signaling. At the time-points where we observed equivalent running- and AICAR-induced muscle pAMPK levels (7 and 14 days), cell proliferation, synaptic plasticity and gene expression, as well as markers of oxidative stress and inflammation in the dentate gyrus (DG) of the hippocampus and lateral entorhinal cortex (LEC) were evaluated. At the 7-day time-point, both regimens increased new DG cell number and brain-derived neurotrophic factor (BDNF) protein levels. Furthermore, microarray analysis of DG and LEC tissue showed a remarkable overlap between running and AICAR in the regulation of neuronal, mitochondrial and metabolism related gene classes. Interestingly, while similar outcomes for both treatments were stable over time in muscle, in the brain an inversion occurred at fourteen days. The compound no longer increased DG cell proliferation or neurotrophin levels, and upregulated expression of apoptotic genes and inflammatory cytokine interleukin-1β. Thus, an exercise mimetic that produces changes in muscle consistent with those of exercise does not have the same sustainable positive effects on the brain, indicating that only running consistently benefits brain function.

Challenges in the management of exercise-induced asthma.

PubMed

Storms, William

2009-05-01

Exercise and physical activity are common triggers of symptoms in patients with asthma, although some individuals - especially athletes - may have symptoms with exercise alone. Exercise-induced bronchospasm (EIB) describes airway hyper-reactivity that is observed following exercise in a patient who is not otherwise diagnosed with asthma; exercise-induced asthma (EIA) describes airway hyper-reactivity associated with exercise in a patient who has persistent asthma. Specific challenges affecting both the diagnosis and treatment of these conditions are discussed in this review. The past decade has seen substantial advances in our understanding of EIA and EIB, including new guidelines on their management. With appropriate therapy, all patients with exercise-related symptoms should be able to reach their desired level of performance.

Afferent thermosensory function in relapsing-remitting multiple sclerosis following exercise-induced increases in body temperature.

PubMed

Filingeri, Davide; Chaseling, Georgia; Hoang, Phu; Barnett, Michael; Davis, Scott L; Jay, Ollie

2017-08-01

What is the central question of this study? Between 60 and 80% of multiple sclerosis (MS) patients experience transient worsening of symptoms with increased body temperature (heat sensitivity). As sensory abnormalities are common in MS, we asked whether afferent thermosensory function is altered in MS following exercise-induced increases in body temperature. What is the main finding and its importance? Increases in body temperature of as little as ∼0.4°C were sufficient to decrease cold, but not warm, skin thermosensitivity (∼10%) in MS, across a wider temperature range than in age-matched healthy individuals. These findings provide new evidence on the impact of heat sensitivity on afferent function in MS, which could be useful for clinical evaluation of this neurological disease. In multiple sclerosis (MS), increases in body temperature result in transient worsening of clinical symptoms (heat sensitivity or Uhthoff's phenomenon). Although the impact of heat sensitivity on efferent physiological function has been investigated, the effects of heat stress on afferent sensory function in MS are unknown. Hence, we quantified afferent thermosensory function in MS following exercise-induced increases in body temperature with a new quantitative sensory test. Eight relapsing-remitting MS patients (three men and five women; 51.4 ± 9.1 years of age; Expanded Disability Status Scale score 2.8 ± 1.1) and eight age-matched control (CTR) subjects (five men and three women; 47.4 ± 9.1 years of age) rated the perceived magnitude of two cold (26 and 22°C) and two warm stimuli (34 and 38°C) applied to the dorsum of the hand before and after 30 min cycling in the heat (30°C air; 30% relative humidity). Exercise produced similar increases in mean body temperature in MS [+0.39°C (95% CI: +0.21, +0.53) P = 0.001] and CTR subjects [+0.41°C (95% CI: +0.25, +0.58) P = 0.001]. These changes were sufficient to decrease thermosensitivity significantly to all cold [26°C stimulus, -9.1% (95% CI: -17.0, -1.5), P = 0.006; 22°C stimulus, -10.6% (95% CI: -17.3, -3.7), P = 0.027], but not warm, stimuli in MS. Contrariwise, CTR subjects showed sensitivity reductions to colder stimuli only [22°C stimulus, -9.7% (95% CI: -16.4, -3.1), P = 0.011]. The observation that reductions in thermal sensitivity in MS were confined to the myelinated cold-sensitive pathway and extended across a wider (including milder and colder) temperature range than what is observed in CTR subjects provides new evidence on the impact of rising body temperature on afferent neural function in MS. Also, our findings support the use of our new approach to investigate afferent sensory function in MS during heat stress. © 2017 The Authors. Experimental Physiology © 2017 The Physiological Society.

Cardiorespiratory fitness and exercise-induced ST segment depression in assessing the risk of sudden cardiac death in men.

PubMed

Hagnäs, Magnus J; Lakka, Timo A; Kurl, Sudhir; Rauramaa, Rainer; Mäkikallio, Timo H; Savonen, Kai; Laukkanen, Jari A

2017-03-01

The aim of this study was to investigate whether information on both cardiorespiratory fitness (CRF) and exercise-induced ST segment depression improves the prediction of sudden cardiac death (SCD) in men. The study was based on a population sample of 2328 men aged 42-60 years, who were followed up for on average 19 years. CRF was assessed with maximal exercise test using respiratory gas analysis, expressed in metabolic equivalents (METs) and dichotomised at eight METs. Exercise-induced ST segment depression was defined as 1 mm ST segment depression in ECG. Altogether 165 SCDs occurred during the follow-up. Men with low CRF (<8 METs) and exercise-induced ST segment depression had 4.8-fold (95% CI 2.9 to 7.9) higher risk of SCD than men with high CRF and without exercise-induced ST segment depression (p=0.013 for interaction) after adjustment for other cardiovascular risk factors. Men with high CRF and exercise-induced ST segment depression did not have a statistically significantly higher risk of SCD (HR 1.9, 95% CI 0.9 to 3.8) than men with high CRF and without exercise-induced ST segment depression. The combination of low CRF and exercise-induced ST segment depression was associated with a markedly increased risk of SCD in men. 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/.

A Randomized Pilot Trial of Remote Ischemic Preconditioning in Heart Failure with Reduced Ejection Fraction

PubMed Central

McDonald, Michael A.; Braga, Juarez R.; Li, Jing; Manlhiot, Cedric; Ross, Heather J.; Redington, Andrew N.

2014-01-01

Background Remote ischemic preconditioning (RIPC) induced by transient limb ischemia confers multi-organ protection and improves exercise performance in the setting of tissue hypoxia. We aimed to evaluate the effect of RIPC on exercise capacity in heart failure patients. Methods We performed a randomized crossover trial of RIPC (4×5-minutes limb ischemia) compared to sham control in heart failure patients undergoing exercise testing. Patients were randomly allocated to either RIPC or sham prior to exercise, then crossed over and completed the alternate intervention with repeat testing. The primary outcome was peak VO2, RIPC versus sham. A mechanistic substudy was performed using dialysate from study patient blood samples obtained after sham and RIPC. This dialysate was used to test for a protective effect of RIPC in a mouse heart Langendorff model of infarction. Mouse heart infarct size with RIPC or sham dialysate exposure was also compared with historical control data. Results Twenty patients completed the study. RIPC was not associated with improvements in peak VO2 (15.6+/−4.2 vs 15.3+/−4.6 mL/kg/min; p = 0.53, sham and RIPC, respectively). In our Langendorff sub-study, infarct size was similar between RIPC and sham dialysate groups from our study patients, but was smaller than expected compared to healthy controls (29.0%, 27.9% [sham, RIPC] vs 51.2% [controls]. We observed less preconditioning among the subgroup of patients with increased exercise performance following RIPC (p<0.04). Conclusion In this pilot study of RIPC in heart failure patients, RIPC was not associated with improvements in exercise capacity overall. However, the degree of effect of RIPC may be inversely related to the degree of baseline preconditioning. These data provide the basis for a larger randomized trial to test the potential benefits of RIPC in patients with heart failure. Trial Registration ClinicalTrials.gov +++++NCT01128790 PMID:25181050

Proteinase-Activated Receptor-2 Sensitivity of Amplified TRPA1 Activity in Skeletal Muscle Afferent Nerves and Exercise Pressor Reflex in Rats with Femoral Artery Occlusion

PubMed Central

Xing, Jihong; Li, Jianhua

2017-01-01

Background/Aims Limb ischemia occurs in peripheral artery disease (PAD). Sympathetic nerve activity (SNA) that regulates blood flow directed to the ischemic limb is exaggerated during exercise in this disease, and transient receptor potential channel A1 (TRPA1) in thin-fiber muscle afferents contributes to the amplified sympathetic response. The purpose of the present study was to determine the role of proteinase-activated receptor-2 (PAR2) in regulating abnormal TRPA1 function and the TRPA1-mediated sympathetic component of the exercise pressor reflex. Methods A rat model of femoral artery ligation was employed to study PAD. Dorsal root ganglion (DRG) tissues were obtained to examine the protein levels of PAR2 using western blot analysis. Current responses induced by activation of TRPA1 in skeletal muscle DRG neurons were characterized using whole-cell patch clamp methods. The blood pressure response to static exercise (i.e., muscle contraction) and stimulation of TRPA1 was also examined after a blockade of PAR2. Results The expression of PAR2 was amplified in DRG neurons of the occluded limb, and PAR2 activation with SL-NH2 (a PAR2 agonist) increased the amplitude of TRPA1 currents to a greater degree in DRG neurons of the occluded limb. Moreover, FSLLRY-NH2 (a PAR antagonist) injected into the arterial blood supply of the hindlimb muscles significantly attenuated the pressor response to muscle contraction and TRPA1 stimulation in rats with occluded limbs. Conclusions The PAR2 signal in muscle sensory nerves contributes to the amplified exercise pressor reflex via TRPA1 mechanisms in rats with femoral artery ligation. These findings provide a pathophysiological basis for autonomic responses during exercise activity in PAD, which may potentially aid in the development of therapeutic approaches for improvement of blood flow in this disease. PMID:29131007

Aspirin enhances the induction of type I allergic symptoms when combined with food and exercise in patients with food-dependent exercise-induced anaphylaxis.

PubMed

Harada, S; Horikawa, T; Ashida, M; Kamo, T; Nishioka, E; Ichihashi, M

2001-08-01

We examined the effect of aspirin as a substitute for exercise in inducing urticaria/anaphylaxis in three patients with food-dependent exercise-induced anaphylaxis (FDEIA). Two of the patients had specific IgE antibodies to wheat and the other had antibodies to shrimp. Administration of aspirin before ingestion of food allergens induced urticaria in one patient and urticaria and hypotension in another, while aspirin alone or food alone elicited no response. The third patient developed urticaria only when he took all three items, i.e. aspirin, food and additional exercise, whereas provocation with any one or or two of these did not induce any symptoms. These findings suggest that aspirin upregulates type I allergic responses to food in patients with FDEIA, and further shows that aspirin synergizes with exercise to provoke symptoms of FDEIA. This is the first report of a synergistic effect of aspirin in inducing urticaria/anaphylaxis, which was confirmed using challenge tests in patients with FDEIA.

Blood flow and oxygen uptake during exercise

NASA Technical Reports Server (NTRS)

Mitchell, J. W.; Stolwijk, J. A. J.; Nadel, E. R.

1973-01-01

A model is developed for predicting oxygen uptake, muscle blood flow, and blood chemistry changes under exercise conditions. In this model, the working muscle mass system is analyzed. The conservation of matter principle is applied to the oxygen in a unit mass of working muscle under transient exercise conditions. This principle is used to relate the inflow of oxygen carried with the blood to the outflow carried with blood, the rate of change of oxygen stored in the muscle myoglobin, and the uptake by the muscle. Standard blood chemistry relations are incorporated to evaluate venous levels of oxygen, pH, and carbon dioxide.

Exercise-Induced Pulmonary Hypertension: Translating Pathophysiological Concepts Into Clinical Practice.

PubMed

Naeije, Robert; Saggar, Rajeev; Badesch, David; Rajagopalan, Sanjay; Gargani, Luna; Rischard, Franz; Ferrara, Francesco; Marra, Alberto M; D' Alto, Michele; Bull, Todd M; Saggar, Rajan; Grünig, Ekkehard; Bossone, Eduardo

2018-01-31

Exercise stress testing of the pulmonary circulation for the diagnosis of latent or early-stage pulmonary hypertension (PH) is gaining acceptance. There is emerging consensus to define exercise-induced PH by a mean pulmonary artery pressure > 30 mm Hg at a cardiac output < 10 L/min and a total pulmonary vascular resistance> 3 Wood units at maximum exercise, in the absence of PH at rest. Exercise-induced PH has been reported in association with a bone morphogenetic receptor-2 gene mutation, in systemic sclerosis, in left heart conditions, in chronic lung diseases, and in chronic pulmonary thromboembolism. Exercise-induced PH is a cause of decreased exercise capacity, may precede the development of manifest PH in a proportion of patients, and is associated with a decreased life expectancy. Exercise stress testing of the pulmonary circulation has to be dynamic and rely on measurements of the components of the pulmonary vascular equation during, not after exercise. Noninvasive imaging measurements may be sufficiently accurate in experienced hands, but suffer from lack of precision, so that invasive measurements are required for individual decision-making. Exercise-induced PH is caused either by pulmonary vasoconstriction, pulmonary vascular remodeling, or by increased upstream transmission of pulmonary venous pressure. This differential diagnosis is clinical. Left heart disease as a cause of exercise-induced PH can be further ascertained by a pulmonary artery wedge pressure above or below 20 mm Hg at a cardiac output < 10 L/min or a pulmonary artery wedge pressure-flow relationship above or below 2 mm Hg/L/min during exercise. Copyright © 2018 American College of Chest Physicians. Published by Elsevier Inc. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Murakami, Taro, E-mail: tamuraka@sgk.ac.jp; Yoshinaga, Mariko

Highlights: •Regulation of amino acid transporter expression in working muscle remains unclear. •Expression of amino acid transporters for leucine were induced by a bout of exercise. •Requirement of leucine in muscle cells might regulate expression of its transporters. •This information is beneficial for understanding the muscle remodeling by exercise. -- Abstract: We here investigated whether an acute bout of endurance exercise would induce the expression of amino acid transporters that regulate leucine transport across plasma and lysosomal membranes in rat skeletal muscle. Rats ran on a motor-driven treadmill at a speed of 28 m/min for 90 min. Immediately after themore » exercise, we observed that expression of mRNAs encoding L-type amino acid transporter 1 (LAT1) and CD98 was induced in the gastrocnemius, soleus, and extensor digitorum longus (EDL) muscles. Sodium-coupled neutral amino acid transporter 2 (SNAT2) mRNA was also induced by the exercise in those three muscles. Expression of proton-assisted amino acid transporter 1 (PAT1) mRNA was slightly but not significantly induced by a single bout of exercise in soleus and EDL muscles. Exercise-induced mRNA expression of these amino acid transporters appeared to be attenuated by repeated bouts of the exercise. These results suggested that the expression of amino acid transporters for leucine may be induced in response to an increase in the requirement for this amino acid in the cells of working skeletal muscles.« less

[Effect of atorvastatin on exercise tolerance in patients with diastolic dysfunction and exercise-induced hypertension].

PubMed

Ye, Ping-xian; Ye, Ping-zhen; Zhu, Jian-hua; Chen, Wei; Gao, Dan-chen

2014-05-01

To investigate the effect of atorvastatin on exercise tolerance in patients with diastolic dysfunction and exercise-induced hypertension. A randomized, double-blind, placebo-controlled prospective study was performed. Sixty patients with diastolic dysfunction (mitral flow velocity E/A <1) and exercise-induced hypertension (SBP>200 mm Hg) treated with atorvastatin (20 mg q.d) or placebo for 1 year. Cardiopulmonary exercise test and exercise blood pressure measurement were performed. Plasma B-natriuretic peptide (BNP) concentration at rest and at peak exercise, plasma high sensitive-C reaction protein (hs-CRP) and endothelin (ET) concentration were determined at baseline and after treatment. After treatment by atorvastatin, the resting SBP, pulse pressure, the peak exercise SBP and BNP were significantly decreased; and the exercise time, metabolic equivalent, maximal oxygen uptake and anaerobic threshold were increased. All of these parameters had significant differences with baseline levels (P<0.05) and the rest pulse pressure, the peak exercise SBP and BNP, and the exercise time had significant differences compared with placebo treatment (P<0.05). Plasma concentrations of hs-CRP and ET were markedly reduced by atorvastatin treatment compared with baseline and placebo (P<0.05). No difference in above parameters was found before and after placebo treatment (P>0.05). In patients with diastolic dysfunction at rest and exercise-induced hypertension, atorvastatin can effectively reduce plasma hs-CRP and ET level, lower blood pressure and peak exercise SBP, decrease peak exercise plasma BNP concentration, and ultimately improve exercise tolerance.

Amyotrophic lateral sclerosis immunoglobulins increase intracellular calcium in a motoneuron cell line.

PubMed

Colom, L V; Alexianu, M E; Mosier, D R; Smith, R G; Appel, S H

1997-08-01

A hybrid motoneuron cell line (VSC4.1) was used as a model system to study the relationship between alterations in intracellular calcium and subsequent cell death induced by immunoglobulin fractions purified from sera of patients with ALS. Using fluo-3 fluorescence imaging, immunoglobulins from 8 of 10 patients with ALS were found to induce transient increases in intracellular calcium ([Ca2+]i) in differentiated VSC4.1 cells. These transient [Ca2+]i increases required extracellular calcium entry through voltage-gated calcium channels sensitive to synthetic FTX and to high concentrations (>1 microM) of omega-agatoxin IVa. The incidence of transient [Ca2+]i increases induced by ALS immunoglobulins correlated with the extent of cytotoxicity induced by the same ALS immunoglobulins in parallel cultures of VSC4.1 cells. Furthermore, manipulations which blocked transient [Ca2+]i increases (addition of synthetic FTX or omega-agatoxin IVa) also inhibited the cytotoxic effects of ALS immunoglobulins. No transient calcium increases were observed in VSC4.1 cells following addition of immunoglobulins from 7 neurologic disease control patients. However, transient [Ca2+]i increases were observed following addition of immunoglobulins from 4 of 5 patients with myasthenia gravis (MG). The [Ca2+]i changes induced by MG immunoglobulins were not blocked by s-FTX, suggesting that they result from a different mechanism than those induced by ALS immunoglobulins. These results suggest that immunoglobulins from patients with ALS can induce transient increases in intracellular calcium in a motoneuron cell line, which may represent early events in the cascade of processes leading to injury and death of susceptible cells.

Outflow-driven Transients from the Birth of Binary Black Holes. II. Primary-induced Accretion Transients

NASA Astrophysics Data System (ADS)

Kimura, Shigeo S.; Murase, Kohta; Mészáros, Peter

2017-12-01

We discuss the electromagnetic radiation from newborn binary black holes (BBHs). As a consequence of the evolution of massive stellar binaries, a binary consisting of a primary black hole (BH) and a secondary Wolf–Rayet star is expected as a BBH progenitor system. We investigate optical transients from the birth of BBHs powered by the Bondi–Hoyle–Lyttleton accretion onto the primary BH, which occur ∼1–10 Gyr earlier than gravitational-wave signals at the BH–BH merger. When the secondary massive star collapses into a BH, it may eject a fraction of its outer material and may form a disk around the primary BH and induces a powerful disk wind. These primary-induced winds can lead to optical transients with a kinetic energy of ∼1047–3 × 1048 erg, an ejecta velocity of 108–109 cm s‑1, a duration of a few days, and an absolute magnitude ranging from about ‑11 to ‑14. The light curves and late-time spectra of these transients are distinctive from those of ordinary supernovae, and detection of this type of transient is possible by future optical transient surveys if the event rate of this transient is comparable to the merger rate of BBHs. This paper focuses on the emissions from disk-driven transients induced by the primary BH, different from Paper I, which focuses on wind-driven transients from the tidally locked secondary massive star.

Progressive pigmentary purpura.

PubMed

Brauer, Jeremy A; Mundi, Jyoti; Chu, Julie; Patel, Rishi; Meehan, Shane; Greenspan, Alan H; Stein, Jennifer

2011-10-15

A 58-year-old man presented for evaluation and treatment of non-tender, non-pruritic, annular patches on the right temple and frontal aspect of the scalp that reddened with exercise. A biopsy specimen showed a purpuric dermatitis with features of lymphocytic vasculitis; a diagnosis of exercise-induced progressive pigmentary purpura was made. Whereas progressive pigmentary purpura is purported to be caused by exercise, other similar appearing entities are associated with exercise, namely exercise-induced vasculitis (EIV). EIV may be considered as an acute microcirculatory deficiency and thermoregulation decompensation that occurs after episodes of exhaustive major muscular activity or after unusual or excessive exercise. The combination of age greater than 50 years, heat, and prolonged exercise are the most potent contributing factors. This is the first report of exercise-induced progressive pigmentary purpura.

Forced running exercise attenuates hippocampal neurogenesis impairment and the neurocognitive deficits induced by whole-brain irradiation via the BDNF-mediated pathway

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ji, Jian-feng; Ji, Sheng-jun; Sun, Rui

Highlights: •Forced exercise can ameliorate WBI induced cognitive impairment in our rat model. •Mature BDNF plays an important role in the effects of forced exercise. •Exercise may be a possible treatment of the radiation-induced cognitive impairment. -- Abstract: Cranial radiotherapy induces progressive and debilitating cognitive deficits, particularly in long-term cancer survivors, which may in part be caused by the reduction of hippocampal neurogenesis. Previous studies suggested that voluntary exercise can reduce the cognitive impairment caused by radiation therapy. However, there is no study on the effect of forced wheel exercise and little is known about the molecular mechanisms mediating themore » effect of exercise. In the present study, we investigated whether the forced running exercise after irradiation had the protective effects of the radiation-induced cognitive impairment. Sixty-four Male Sprague–Dawley rats received a single dose of 20 Gy or sham whole-brain irradiation (WBI), behavioral test was evaluated using open field test and Morris water maze at 2 months after irradiation. Half of the rats accepted a 3-week forced running exercise before the behavior detection. Immunofluorescence was used to evaluate the changes in hippocampal neurogenesis and Western blotting was used to assess changes in the levels of mature brain-derived neurotrophic factor (BDNF), phosphorylated tyrosine receptor kinase B (TrkB) receptor, protein kinase B (Akt), extracellular signal-regulated kinase (ERK), calcium-calmodulin dependent kinase (CaMKII), cAMP-calcium response element binding protein (CREB) in the BDNF–pCREB signaling. We found forced running exercise significantly prevented radiation-induced cognitive deficits, ameliorated the impairment of hippocampal neurogenesis and attenuated the down-regulation of these proteins. Moreover, exercise also increased behavioral performance, hippocampal neurogenesis and elevated BDNF–pCREB signaling in non-irradiation group. These results suggest that forced running exercise offers a potentially effective treatment for radiation-induced cognitive deficits.« less

Acute aerobic exercise induces a preferential mobilisation of plasmacytoid dendritic cells into the peripheral blood in man.

PubMed

Brown, Frankie F; Campbell, John P; Wadley, Alex J; Fisher, James P; Aldred, Sarah; Turner, James E

2018-05-31

Dendritic cells (DCs) are important sentinel cells of the immune system responsible for presenting antigen to T cells. Exercise is known to cause an acute and transient increase in the frequency of DCs in the bloodstream in humans, yet there are contradictory findings in the literature regarding the phenotypic composition of DCs mobilised during exercise, which may have implications for immune regulation and health. Accordingly, we sought to investigate the composition of DC sub-populations mobilised in response to acute aerobic exercise. Nine healthy males (age, 21.9 ± 3.6 years; height, 177.8 ± 5.4 cm; body mass, 78.9 ± 10.8 kg; body mass index, 24.9 ± 3.3 kg·m 2 ; V̇O 2 MAX , 41.5 ± 5.1 mL·kg·min -1 ) cycled for 20 min at 80% V̇O 2 MAX . Blood was sampled at baseline, during the final minute of exercise and 30 min later. Using flow cytometry, total DCs were defined as Lineage- (CD3, CD19, CD20, CD14, CD56) HLA-DR+ and subsequently identified as plasmacytoid DCs (CD303+) and myeloid DCs (CD303-). Myeloid DCs were analysed for expression of CD1c and CD141 to yield four sub-populations; CD1c-CD141+; CD1c+CD141+; CD1c+CD141- and CD1c-CD141-. Expression of CD205 was also analysed on all DC sub-populations to identify DCs capable of recognising apoptotic and necrotic cells. Total DCs increased by 150% during exercise (F (1,10)  = 60; p < 0.05, η 2  = 0.9). Plasmacytoid DCs mobilised to a greater magnitude than myeloid DCs (195 ± 131% vs. 131 ± 100%; p < 0.05). Among myeloid DCs, CD1c-CD141- cells showed the largest exercise-induced mobilisation (167 ± 122%), with a stepwise pattern observed among the remaining sub-populations: CD1c+CD141- (79 ± 50%), followed by CD1c+CD141+ (44 ± 41%), with the smallest response shown by CD1c-CD141+ cells (23 ± 54%) (p < 0.05). Among myeloid DCs, CD205- cells were the most exercise responsive. All DC subsets returned to resting levels within 30 min of exercise cessation. These results show that there is a preferential mobilisation of plasmacytoid DCs during exercise. Given the functional repertoire of plasmacytoid DCs, which includes the production of interferons against viral and bacterial pathogens, these findings indicate that exercise may augment immune-surveillance by preferentially mobilising effector cells; these findings have general implications for the promotion of exercise for health, and specifically for the optimisation of DC harvest for cancer immunotherapy. Copyright © 2018 Elsevier Inc. All rights reserved.

High resolution imaging studies into the formation of laser-induced periodic surface structures.

PubMed

Kerr, N C; Clark, S E; Emmony, D C

1989-09-01

We report the results of an investigation into the formation mechanism of laser-induced ripple structures based on obtaining direct images of a surface while the transient heating induced by a KrF excimer laser is still present. These images reveal transient but well-defined periodic heating patterns which, if enough subsequent excimer pulses are incident on the surface, become permanently induced ripple structures. It is evident from these transient images that the surface heating is confined to the induced structures, thus strongly supporting the idea that at low fluences the ripples are formed by localizing surface melting.

Effects of endotoxin induced lung injury and exercise in goats/sheep. Final report, 1 February 1992-2 June 1993

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mundie, T.G.

This study was designed the effects of exercise performed on animals already injured with E. coli endotoxin. This would tell us whether exercise makes the lung injury worse. It would also tell us how much exercise performance is impaired. These studies were designed to give further insights into the underlying causes of acute lung injury. Premature termination of the study prevented completion of the research project. It appeared from the limited experimentation conducted that maximal exercise was impaired by endotoxin-induced lung injury. Conclusions regarding exacerbation of endotoxin-induced lung injury cannot be made.... Acute lung injury, Maximal exercise, Endotoxin.

Spinning-induced Rhabdomyolysis and the Risk of Compartment Syndrome and Acute Kidney Injury

PubMed Central

DeFilippis, Ersilia M.; Kleiman, David A.; Derman, Peter B.; DiFelice, Gregory S.; Eachempati, Soumitra R.

2014-01-01

Exercise-induced rhabdomyolysis related to military training, marathon running, and other forms of strenuous exercise has been reported. The incidence of acute kidney injury appears to be lower in exercise-induced cases. We present 2 cases of exercise-induced rhabdomyolysis following spinning classes, one of which was further complicated by acute compartment syndrome requiring bilateral fasciotomies of the anterior thigh and acute kidney injury. With vigorous hydration and urine pH monitoring, both patients exhibited good mobility, sensation, and renal function on discharge. PMID:24982706

[Exercise-induced inspiratory stridor. An important differential diagnosis of exercise-induced asthma].

PubMed

Christensen, Pernille; Thomsen, Simon Francis; Rasmussen, Niels; Backer, Vibeke

2007-11-19

Recent studies suggest that exercise-induced inspiratory stridor (EIIS) is an important and often overlooked differential diagnosis of exercise-induced asthma. EIIS is characterised by astma-like symptoms, but differs by inspiratory limitation, fast recovery, and a lack of effect of inhaled bronchodilators. The prevalence of EIIS is reported to be 5-27%, and affects both children and adults. The pathophysiology, the pathogenesis, and the treatment of the condition are not yet clarified. At present, a population-based study is being conducted in order to address these points.

INDUCIBLE TRANSIENT CENTRAL RETINAL ARTERY VASOSPASM: A CASE REPORT.

PubMed

Mishulin, Aleksey; Ghandi, Sachin; Apple, Daniel; Lin, Xihui; Hu, Jonathan; Abrams, Gary W

2017-09-27

To report a case of inducible transient central retinal artery vasospasm with associated imaging. Observational case report. A 51-year-old man presented for outpatient follow-up for recurrent inducible transient vision loss in his right eye. He experienced an episode during examination and was found to have central retinal artery vasospasm. Fundus photography and fluorescein angiography obtained during his vasospastic attack confirmed retinal arterial vasospasm. Treatment with a calcium-channel blocker (nifedipine) has been effective in preventing recurrent attacks. Idiopathic primary vasospasm is a rare cause of transient vision loss that is difficult to confirm because of the transient nature. We obtained imaging showing the initiation and resolution of the vasospastic event. The patient was then successfully treated with a calcium-channel blocker.

Transient Receptor Potential Vanilloid 2 Regulates Myocardial Response to Exercise

PubMed Central

Naticchioni, Mindi; Karani, Rajiv; Smith, Margaret A.; Onusko, Evan; Robbins, Nathan; Jiang, Min; Radzyukevich, Tatiana; Fulford, Logan; Gao, Xu; Apel, Ryan; Heiny, Judith; Rubinstein, Jack; Koch, Sheryl E.

2015-01-01

The myocardial response to exercise is an adaptive mechanism that permits the heart to maintain cardiac output via improved cardiac function and development of hypertrophy. There are many overlapping mechanisms via which this occurs with calcium handling being a crucial component of this process. Our laboratory has previously found that the stretch sensitive TRPV2 channels are active regulators of calcium handling and cardiac function under baseline conditions based on our observations that TRPV2-KO mice have impaired cardiac function at baseline. The focus of this study was to determine the cardiac function of TRPV2-KO mice under exercise conditions. We measured skeletal muscle at baseline in WT and TRPV2-KO mice and subjected them to various exercise protocols and measured the cardiac response using echocardiography and molecular markers. Our results demonstrate that the TRPV2-KO mouse did not tolerate forced exercise although they became increasingly exercise tolerant with voluntary exercise. This occurs as the cardiac function deteriorates further with exercise. Thus, our conclusion is that TRPV2-KO mice have impaired cardiac functional response to exercise. PMID:26356305

Oxygen radical absorbance capacity (ORAC) and exercise-induced oxidative stress in trotters.

PubMed

Kinnunen, Susanna; Hyyppä, Seppo; Lehmuskero, Arja; Oksala, Niku; Mäenpää, Pekka; Hänninen, Osmo; Atalay, Mustafa

2005-12-01

Strenuous exercise is a potent inducer of oxidative stress, which has been suggested to be associated with disturbances in muscle homeostasis, fatigue and injury. There is no comprehensive or uniform view of the antioxidant status in horses. We have previously shown that moderate exercise induces protein oxidation in trotters. The aim of this study was to measure the antioxidative capacity of the horse in relation to different antioxidant components and oxidative stress markers after a single bout of moderate exercise to elucidate the mechanisms of antioxidant protection in horses. Eight clinically normal and regularly trained standard-bred trotters were treadmill-exercised for 53 min at moderate intensity. Blood samples were collected prior to and immediately after exercise and at 4 and 24 h of recovery. Muscle biopsies from the middle gluteal muscle were taken before exercise and after 4 h of recovery. Acute induction of oxygen radical absorbance capacity (ORAC) did not prevent exercise-induced oxidative stress, which was demonstrated by increased lipid hydroperoxides (LPO). Pre-exercise ORAC levels were, however, a determinant of total glutathione content of the blood after 4 and 24 h of recovery. Furthermore, baseline ORAC level correlated negatively with 4-h recovery LPO levels. Our results imply that horses are susceptible to oxidative stress, but a stronger antioxidant capacity may improve coping with exercise-induced oxidative stress.

Exercise-induced ST-segment elevation during treadmill exercise testing.

PubMed

Patanè, Salvatore; Marte, Filippo

2010-09-03

The exercise electrocardiogram is a commonly used non-invasive and inexpensive method for detection of electrocardiogram (ECG) changes secondary to myocardial ischemia. It has been reported that in patients with a first myocardial infarction and without residual ischemia, exercise-induced ST-segment elevation in Q leads is related to a more damaged coronary microcirculation and to less viable myocardium. Exercise-induced ST-segment elevation is a rare phenomenon in patients without prior myocardial infarction. When occurring purely during exercise, coronary lesions are frequent and often severe, and on the other hand ST-segment elevation of the recovery phase is frequently associated with normal arteries or less severe lesions. We present a case of exercise-induced ST-segment elevation in a 51-year-old Italian man. Coronary angiography revealed a significant left anterior descending coronary artery stenosis, a significant circumflex coronary artery stenosis, a significant first obtuse marginal coronary artery stenosis and a significant second obtuse marginal coronary artery stenosis. Percutaneous transluminal coronary angioplasty with implantation of stents was successfully performed. Also this case is illustrative of the rare phenomenon of exercise-induced ST-segment elevation. Copyright © 2008 Elsevier B.V. All rights reserved.

Involvement of mesolimbic dopaminergic network in neuropathic pain relief by treadmill exercise

PubMed Central

Wakaizumi, Kenta; Kondo, Takashige; Hamada, Yusuke; Narita, Michiko; Kawabe, Rui; Narita, Hiroki; Watanabe, Moe; Kato, Shigeki; Senba, Emiko; Kobayashi, Kazuto; Yamanaka, Akihiro

2016-01-01

Background Exercise alleviates pain and it is a central component of treatment strategy for chronic pain in clinical setting. However, little is known about mechanism of this exercise-induced hypoalgesia. The mesolimbic dopaminergic network plays a role in positive emotions to rewards including motivation and pleasure. Pain negatively modulates these emotions, but appropriate exercise is considered to activate the dopaminergic network. We investigated possible involvement of this network as a mechanism of exercise-induced hypoalgesia. Methods In the present study, we developed a protocol of treadmill exercise, which was able to recover pain threshold under partial sciatic nerve ligation in mice, and investigated involvement of the dopaminergic reward network in exercise-induced hypoalgesia. To temporally suppress a neural activation during exercise, a genetically modified inhibitory G-protein-coupled receptor, hM4Di, was specifically expressed on dopaminergic pathway from the ventral tegmental area to the nucleus accumbens. Results The chemogenetic-specific neural suppression by Gi-DREADD system dramatically offset the effect of exercise-induced hypoalgesia in transgenic mice with hM4Di expressed on the ventral tegmental area dopamine neurons. Additionally, anti-exercise-induced hypoalgesia effect was significantly observed under the suppression of neurons projecting out of the ventral tegmental area to the nucleus accumbens as well. Conclusion Our findings suggest that the dopaminergic pathway from the ventral tegmental area to the nucleus accumbens is involved in the anti-nociception under low-intensity exercise under a neuropathic pain-like state. PMID:27909152

Workshop targets development of geodetic transient detection methods: 2009 SCEC Annual Meeting: Workshop on transient anomalous strain detection; Palm Springs, California, 12-13 September 2009

USGS Publications Warehouse

Murray-Moraleda, Jessica R.; Lohman, Rowena

2010-01-01

The Southern California Earthquake Center (SCEC) is a community of researchers at institutions worldwide working to improve understanding of earthquakes and mitigate earthquake risk. One of SCEC's priority objectives is to “develop a geodetic network processing system that will detect anomalous strain transients.” Given the growing number of continuously recording geodetic networks consisting of hundreds of stations, an automated means for systematically searching data for transient signals, especially in near real time, is critical for network operations, hazard monitoring, and event response. The SCEC Transient Detection Test Exercise began in 2008 to foster an active community of researchers working on this problem, explore promising methods, and combine effective approaches in novel ways. A workshop was held in California to assess what has been learned thus far and discuss areas of focus as the project moves forward.

Regular voluntary exercise cures stress-induced impairment of cognitive function and cell proliferation accompanied by increases in cerebral IGF-1 and GST activity in mice.

PubMed

Nakajima, Sanae; Ohsawa, Ikuroh; Ohta, Shigeo; Ohno, Makoto; Mikami, Toshio

2010-08-25

Chronic stress impairs cognitive function and hippocampal neurogenesis. This impairment is attributed to increases in oxidative stress, which result in the accumulation of lipid peroxide. On the other hand, voluntary exercise enhances cognitive function, hippocampal neurogenesis, and antioxidant capacity in normal animals. However, the effects of voluntary exercise on cognitive function, neurogenesis, and antioxidants in stressed mice are unclear. This study was designed to investigate whether voluntary exercise cures stress-induced impairment of cognitive function accompanied by improvement of hippocampal neurogenesis and increases in antioxidant capacity. Stressed mice were exposed to chronic restraint stress (CRS), which consisted of 12h immobilization daily and feeding in a small cage, for 8 weeks. Exercised mice were allowed free access to a running wheel during their exposure to CRS. At the 6th week, cognitive function was examined using the Morris water maze (MWM) test. Daily voluntary exercise restored stress-induced impairment of cognitive function and the hippocampal cell proliferation of newborn cells but not cell survival. Voluntary exercise increased insulin-like growth factor 1 (IGF-1) protein and mRNA expression in the cerebral cortex and liver, respectively. In addition, CRS resulted in a significant increase in the number of 4-hydrosynonenal (4-HNE)-positive cells in the hippocampal dentate gyrus; whereas, voluntary exercise inhibited it and enhanced glutathione s-transferases (GST) activity in the brain. These findings suggest that voluntary exercise attenuated the stress-induced impairment of cognitive function accompanied by improvement of cell proliferation in the dentate gyrus. This exercise-induced improvement was attributed to exercise-induced enhancement of IGF-1 protein and GST activity in the brain. Copyright 2010 Elsevier B.V. All rights reserved.

Appetite and Energy Intake Responses to Acute Energy Deficits in Females versus Males

PubMed Central

ALAJMI, NAWAL; DEIGHTON, KEVIN; KING, JAMES A.; REISCHAK-OLIVEIRA, ALVARO; WASSE, LUCY K.; JONES, JENNY; BATTERHAM, RACHEL L.; STENSEL, DAVID J.

2016-01-01

ABSTRACT Purpose To explore whether compensatory responses to acute energy deficits induced by exercise or diet differ by sex. Methods In experiment one, 12 healthy women completed three 9-h trials (control, exercise-induced (Ex-Def) and food restriction–induced energy deficit (Food-Def)) with identical energy deficits being imposed in the Ex-Def (90-min run, ∼70% of V˙O2max) and Food-Def trials. In experiment two, 10 men and 10 women completed two 7-h trials (control and exercise). Sixty minutes of running (∼70% of V˙O2max) was performed at the beginning of the exercise trial. The participants rested throughout the remainder of the exercise trial and during the control trial. Appetite ratings, plasma concentrations of gut hormones, and ad libitum energy intake were assessed during main trials. Results In experiment one, an energy deficit of approximately 3500 kJ induced via food restriction increased appetite and food intake. These changes corresponded with heightened concentrations of plasma acylated ghrelin and lower peptide YY3–36. None of these compensatory responses were apparent when an equivalent energy deficit was induced by exercise. In experiment two, appetite ratings and plasma acylated ghrelin concentrations were lower in exercise than in control, but energy intake did not differ between trials. The appetite, acylated ghrelin, and energy intake response to exercise did not differ between men and women. Conclusions Women exhibit compensatory appetite, gut hormone, and food intake responses to acute energy restriction but not in response to an acute bout of exercise. Additionally, men and women seem to exhibit similar acylated ghrelin and PYY3–36 responses to exercise-induced energy deficits. These findings advance understanding regarding the interaction between exercise and energy homeostasis in women. PMID:26465216

Update on Exercise-Induced Asthma. A Report of the Olympic Exercise Asthma Summit Conference.

ERIC Educational Resources Information Center

Storms, William W.; Joyner, David M.

1997-01-01

Summarizes results from the Olympic Exercise Asthma Summit Conference, offering the latest on identifying and managing exercise-induced asthma (EIA). Concludes that effective pharmacologic and nonpharmacologic treatment is available, but EIA is underrecognized and underdiagnosed. Physicians should look for it in all patients, including school…

Chronic pain management in the obese patient: a focused review of key challenges and potential exercise solutions

PubMed Central

Zdziarski, Laura Ann; Wasser, Joseph G; Vincent, Heather K

2015-01-01

In obese persons, general and specific musculoskeletal pain is common. Emerging evidence suggests that obesity modulates pain via several mechanisms such as mechanical loading, inflammation, and psychological status. Pain in obesity contributes to deterioration of physical ability, health-related quality of life, and functional dependence. We present the accumulating evidence showing the interrelationships of mechanical stress, inflammation, and psychological characteristics on pain. While acute exercise may transiently exacerbate pain symptoms, regular participation in exercise can lower pain severity or prevalence. Aerobic exercise, resistance exercise, or multimodal exercise programs (combination of the two types) can reduce joint pain in young and older obese adults in the range of 14%–71.4% depending on the study design and intervention used. While published attrition rates with regular exercise are high (∼50%), adherence to exercise may be enhanced with modification to exercise including the accumulation of several exercise bouts rather than one long session, reducing joint range of motion, and replacing impact with nonimpact activity. This field would benefit from rigorous comparative efficacy studies of exercise intensity, frequency, and mode on specific and general musculoskeletal pain in young and older obese persons. PMID:25709495

Cardiac Ischemia/Reperfusion Injury: The Beneficial Effects of Exercise.

PubMed

Borges, Juliana Pereira; da Silva Verdoorn, Karine

2017-01-01

Cardiac ischemia reperfusion injury (IRI) occurs when the myocardium is revascularized after an episode of limited or absent blood supply. Many changes, including free radical production, calcium overload, protease activation, altered membrane lipids and leukocyte activation, contribute to IRI-induced myocardium damage. Aerobic exercise is the only countermeasure against IRI that can be sustained on a regular basis in clinical practice. Interestingly, both short-term (3-5 days) and long-term (several weeks) exercise increase myocardial tolerance, reduce infarct size area and arrhythmias induced by IRI. Exercise protects the heart against IRI in a biphasic manner. The early phase of cardioprotection occurs between 30 min and 3 h following an acute exercise bout, whilst the late phase is achieved within 24 h after the exercise bout and persists for several days. As for the exercise intensity, although controversial data exists, it is feasible that the amount of cardioprotection is proportional to exercise intensity and only achieved above a critical threshold. It is known that aerobic exercise produces a cardioprotective phenotype, however the mechanisms responsible for this phenomenon remain unclear. Apparently, aerobic exercise-induced preconditioning is dependent on several factors that work together to protect the heart. Altered nitric oxide (NO) signaling, increased levels of heat shock proteins (HSPs), enhanced function of ATP-sensitive potassium channels, increased activation of opioids system, and enhanced antioxidant capacity may contribute to exercise-induced cardioprotection. Much has been discovered from animal models involving exercise-induced cardioprotection against cardiac IRI, however translating these findings to clinical practice still represents the major challenge in this field.

Exercise reverses metabolic syndrome in high-fat diet-induced obese rats.

PubMed

Touati, Sabeur; Meziri, Fayçal; Devaux, Sylvie; Berthelot, Alain; Touyz, Rhian M; Laurant, Pascal

2011-03-01

Chronic consumption of a high-fat diet induces obesity. We investigated whether exercise would reverse the cardiometabolic disorders associated with obesity without it being necessary to change from a high- to normal-fat diet. Sprague-Dawley rats were placed on a high-fat (HFD) or control diet (CD) for 12 wk. HFD rats were then divided into four groups: sedentary HFD (HFD-S), exercise trained (motor treadmill for 12 wk) HFD (HFD-Ex), modified diet (HFD to CD; HF/CD-S), and exercise trained with modified diet (HF/CD-Ex). Cardiovascular risk parameters associated with metabolic syndrome were measured, and contents of aortic Akt, phospho-Akt at Ser (473), total endothelial nitric oxide synthase (eNOS), and phospho-eNOS at Ser (1177) were determined by Western blotting. Chronic consumption of HFD induced a metabolic syndrome. Exercise and dietary modifications reduced adiposity, improved glucose and insulin levels and plasma lipid profile, and exerted an antihypertensive effect. Exercise was more effective than dietary modification in improving plasma levels of thiobarbituric acid-reacting substance and in correcting the endothelium-dependent relaxation to acetylcholine and insulin. Furthermore, independent of the diet used, exercise increased Akt and eNOS phosphorylation. Metabolic syndrome induced by HFD is reversed by exercise and diet modification. It is demonstrated that exercise training induces these beneficial effects without the requirement for dietary modification, and these beneficial effects may be mediated by shear stress-induced Akt/eNOS pathway activation. Thus, exercise may be an effective strategy to reverse almost all the atherosclerotic risk factors linked to obesity, particularly in the vasculature.

Physical Exercise Counteracts Stress-induced Upregulation of Melanin-concentrating Hormone in the Brain and Stress-induced Persisting Anxiety-like Behaviors.

PubMed

Kim, Tae-Kyung; Han, Pyung-Lim

2016-08-01

Chronic stress induces anxiety disorders, whereas physical exercise is believed to help people with clinical anxiety. In the present study, we investigated the mechanisms underlying stress-induced anxiety and its counteraction by exercise using an established animal model of anxiety. Mice treated with restraint for 2 h daily for 14 days exhibited anxiety-like behaviors, including social and nonsocial behavioral symptoms, and these behavioral impairments lasted for more than 12 weeks after the stress treatment was removed. Despite these lasting behavioral changes, wheel-running exercise treatment for 1 h daily from post-stress days 1 - 21 counteracted anxiety-like behaviors, and these anxiolytic effects of exercise persisted for more than 2 months, suggesting that anxiolytic effects of exercise stably induced. Repeated restraint treatment up-regulated the expression of the neuropeptide, melanin-concentrating hormone (MCH), in the lateral hypothalamus, hippocampus, and basolateral amygdala, the brain regions important for emotional behaviors. In an in vitro study, treatment of HT22 hippocampal cells with glucocorticoid increased MCH expression, suggesting that MCH upregulation can be initially triggered by the stress hormone, corticosterone. In contrast, post-stress treatment with wheel-running exercise reduced the stress-induced increase in MCH expression to control levels in the lateral hypothalamus, hippocampus and basolateral amygdala. Administration of an MCH receptor antagonist (SNAP94847) to stress-treated mice was therapeutic against stress-induced anxiety-like behaviors. These results suggest that repeated stress produces long-lasting anxiety-like behaviors and upregulates MCH in the brain, while exercise counteracts stress-induced MCH expression and persisting anxiety-like behaviors.

Effects of menstrual cycle, oral contraception, and training on exercise-induced changes in circulating DHEA-sulphate and testosterone in young women.

PubMed

Enea, C; Boisseau, N; Ottavy, M; Mulliez, J; Millet, C; Ingrand, I; Diaz, V; Dugué, B

2009-06-01

The objective of this study was to ascertain the effects of menstrual cycle, oral contraception, and training status on the exercise-induced changes in circulating DHEA-sulphate and testosterone in young women. Twenty-eight healthy women were assigned to an untrained group (n = 16) or a trained group (n = 12) depending on their training background. The untrained group was composed of nine oral contraceptive users (OC+) and seven eumenorrheic women (OC-). The trained group was composed of OC+ subjects only. All the OC+ subjects were taking the same low-dose oral contraception. Three laboratory sessions were organised in a randomised order: a prolonged exercise test until exhaustion, a short-term exhaustive exercise test, and a control session. Blood specimens were collected before, during and after the exercise tests and at the same time of the day during the control session. Basal circulating testosterone was significantly lower in trained as compared to untrained subjects. In all subjects, the prolonged exhaustive exercise induced a significant increase in circulating DHEA-s and testosterone. The short-term exercise induced a significant increase in circulating DHEA-s in untrained eumenorrheic and in trained OC users only. Menstrual phases in OC- did not influence the responses. It was found that exhaustive physical exercise induced an increase in circulating DHEA-s and testosterone in young women. Oral contraception may limit short-term exercise-induced changes.

Principles of Exercise Prescription, and How They Influence Exercise-Induced Changes of Transcription Factors and Other Regulators of Mitochondrial Biogenesis.

PubMed

Granata, Cesare; Jamnick, Nicholas A; Bishop, David J

2018-04-19

Physical inactivity represents the fourth leading risk factor for mortality, and it has been linked with a series of chronic disorders, the treatment of which absorbs ~ 85% of healthcare costs in developed countries. Conversely, physical activity promotes many health benefits; endurance exercise in particular represents a powerful stimulus to induce mitochondrial biogenesis, and it is routinely used to prevent and treat chronic metabolic disorders linked with sub-optimal mitochondrial characteristics. Given the importance of maintaining a healthy mitochondrial pool, it is vital to better characterize how manipulating the endurance exercise dose affects cellular mechanisms of exercise-induced mitochondrial biogenesis. Herein, we propose a definition of mitochondrial biogenesis and the techniques available to assess it, and we emphasize the importance of standardizing biopsy timing and the determination of relative exercise intensity when comparing different studies. We report an intensity-dependent regulation of exercise-induced increases in nuclear peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) protein content, nuclear phosphorylation of p53 (serine 15), and PGC-1α messenger RNA (mRNA), as well as training-induced increases in PGC-1α and p53 protein content. Despite evidence that PGC-1α protein content plateaus within a few exercise sessions, we demonstrate that greater training volumes induce further increases in PGC-1α (and p53) protein content, and that short-term reductions in training volume decrease the content of both proteins, suggesting training volume is still a factor affecting training-induced mitochondrial biogenesis. Finally, training-induced changes in mitochondrial transcription factor A (TFAM) protein content are regulated in a training volume-dependent manner and have been linked with training-induced changes in mitochondrial content.

Beat by beat stroke volume assessment by PDE in upright and supine exercise

NASA Technical Reports Server (NTRS)

1980-01-01

A 3.0 MHz pulse Doppler echocardiograph was used to estimate instantaneous stroke volume and cardiac output in 8 men during steady state supine and upright exercise at 300 kpm/min which were compared with other studies utilizing invasive procedures. The mean transients in heart rate and stroke volume and cardiac output for the first 20 sec of exercise in each posture were then determined. Centerline blood velocities were obtained in the ascending aorta with the transducer positioned manually in the suprasternal notch. Mean supine values for stroke volume and cardiac output at rest and exercise were 111 (6.4) and 112 ml (9.7 L/min), respectively, for supine. The corresponding results for upright were 76 (5.6) and 92 ml (8.4 L/min). These values compare favorably with prior studies. The transient response of cardiac output following the onset of upright was about twice as fast as in S because of the rapid and almost immediate upsurge in stroke volume. In supine, only heart rate served to augment cardiac output as stroke volume initially fell. The faster initial aortic flow in upright must represent the rapid mobilization of pooled venous blood from the leg veins which more than accounts for the additional volume (184 ml) of blood passing through the aorta during upright compared with supine in the first 20 sec.

Acute effect of exercise intensity and duration on acylated ghrelin and hunger in men.

PubMed

Broom, David R; Miyashita, Masashi; Wasse, Lucy K; Pulsford, Richard; King, James A; Thackray, Alice E; Stensel, David J

2017-03-01

Acute exercise transiently suppresses the orexigenic gut hormone acylated ghrelin, but the extent to which exercise intensity and duration determine this response is not fully understood. The effects of manipulating exercise intensity and duration on acylated ghrelin concentrations and hunger were examined in two experiments. In experiment one, nine healthy males completed three, 4-h conditions (control, moderate-intensity running (MOD) and vigorous-intensity running (VIG)), with an energy expenditure of ~2.5 MJ induced in both MOD (55-min running at 52% peak oxygen uptake (V.O 2peak )) and VIG (36-min running at 75% V.O 2peak ). In experiment two, nine healthy males completed three, 9-h conditions (control, 45-min running (EX45) and 90-min running (EX90)). Exercise was performed at 70% V.O 2peak In both experiments, participants consumed standardised meals, and acylated ghrelin concentrations and hunger were quantified at predetermined intervals. In experiment one, delta acylated ghrelin concentrations were lower than control in MOD (ES = 0.44, P = 0.01) and VIG (ES = 0.98, P < 0.001); VIG was lower than MOD (ES = 0.54, P = 0.003). Hunger ratings were similar across the conditions (P = 0.35). In experiment two, delta acylated ghrelin concentrations were lower than control in EX45 (ES = 0.77, P < 0.001) and EX90 (ES = 0.68, P < 0.001); EX45 and EX90 were similar (ES = 0.09, P = 0.55). Hunger ratings were lower than control in EX45 (ES = 0.20, P = 0.01) and EX90 (ES = 0.27, P = 0.001); EX45 and EX90 were similar (ES = 0.07, P = 0.34). Hunger and delta acylated ghrelin concentrations remained suppressed at 1.5 h in EX90 but not EX45. In conclusion, exercise intensity, and to a lesser extent duration, are determinants of the acylated ghrelin response to acute exercise. © 2017 Society for Endocrinology.

Carbohydrate Ingestion Before and During Soccer Match Play and Blood Glucose and Lactate Concentrations

PubMed Central

Russell, Mark; Benton, David; Kingsley, Michael

2014-01-01

Context: The ingestion of carbohydrate (CHO) before and during exercise and at halftime is commonly recommended to soccer players for maintaining blood glucose concentrations throughout match play. However, an exercise-induced rebound glycemic response has been observed in the early stages of the second half of simulated soccer-specific exercise when CHO-electrolyte beverages were consumed regularly. Therefore, the metabolic effects of CHO beverage consumption throughout soccer match play remain unclear. Objective: To investigate the blood glucose and blood lactate responses to CHOs ingested before and during soccer match play. Design: Crossover study. Setting: Applied research study. Patients or Other Participants: Ten male outfield academy soccer players (age = 15.6 ± 0.2 years, height = 1.74 ± 0.02 m, mass = 65.3 ± 1.9 kg, estimated maximal oxygen consumption = 58.4 ± 0.8 mL·kg−1·min−1). Intervention(s): Players received a 6% CHO-electrolyte solution or an electrolyte (placebo) solution 2 hours before kickoff, before each half (within 10 minutes), and every 15 minutes throughout exercise. Blood samples were obtained at rest, every 15 minutes during the match (first half: 0–15, 15–30, and 30–45 minutes; second half: 45–60, 60–75, and 75–90 minutes) and 10 minutes into the halftime break. Main Outcome Measure(s): Metabolic responses (blood glucose and blood lactate concentrations) and markers of exercise intensity (heart rate) were recorded. Results: Supplementation influenced the blood glucose response to exercise (time × treatment interaction effect: P ≤ .05), such that glucose concentrations were higher at 30 to 45 minutes in the CHO than in the placebo condition. However, in the second half, blood glucose concentrations were similar between conditions because of transient reductions from peak values occurring in both trials at halftime. Blood lactate concentrations were elevated above those at rest in the first 15 minutes of exercise (time-of-sample effect: P < .001) and remained elevated throughout exercise. Supplementation did not influence the pattern of response (time × treatment interaction effect: P = .49). Conclusions: Ingestion of a 6% CHO-electrolyte beverage before and during soccer match play did not benefit blood glucose concentrations throughout the second half of exercise. PMID:24933430

The Effects of Creatine Supplementation on Exercise-Induced Muscle Damage.

ERIC Educational Resources Information Center

Rawson, Eric S.; Gunn, Bridget; Clarkson, Priscilla M.

2001-01-01

Investigated the effects of oral creatine (Cr) supplementation on markers of exercise-induced muscle damage following high-force eccentric exercise in men randomly administered Cr or placebo. Results indicated that 5 days of Cr supplementation did not reduce indirect makers of muscle damage or enhance recovery from high-force eccentric exercise.…

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.

Modeling static and dynamic human cardiovascular responses to exercise.

PubMed

Stremel, R W; Bernauer, E M; Harter, L W; Schultz, R A; Walters, R F

1975-08-01

A human performance model has been developed and described [9] which portrays the human circulatory, thermo regulatory and energy-exchange systems as an intercoupled set. In this model, steady state or static relationships are used to describe oxygen consumption and blood flow. For example, heart rate (HTRT) is calculated as a function of the oxygen and the thermo-regulatory requirements of each body compartment, using the steady state work values of cardiac output (CO, sum of all compartment blood flows) and stroke volume (SV, assumed maximal after 40% maximal oxygen consumption): HTRT=CO/SV. The steady state model has proven to be an acceptable first approximation, but the inclusion of transient characteristics are essential in describing the overall systems' adjustment to exercise stress. In the present study, the dynamic transient characteristics of heart rate, stroke volume and cardiac output were obtained from experiments utilizing step and sinusoidal forcing of work. The gain and phase relationships reveal a probable first order system with a six minute time constant, and are utilized to model the transient characteristics of these parameters. This approach leads to a more complex model but a more accurate representation of the physiology involved. The instrumentation and programming essential to these experiments are described.

Effects of Visfatin Gene Polymorphism RS4730153 on Exercise-induced Weight Loss of Obese Children and Adolescents of Han Chinese

PubMed Central

Lai, Aiping; Chen, Wenhe; Helm, Kelly

2013-01-01

Visfatin is a recently discovered adipokine that contributes to glucose and obesity-related conditions. This study investigates Visfatin RS4730153 polymorphism from the perspectives of its relations with glucose/lipid metabolism and its influence on the effects of exercise-induced weight loss. Eighty-eight obese Han Chinese children and adolescents were randomly selected from a 2008 Shanghai Weight Loss Summer Camp and were supervised to complete a 4 week aerobic exercise training program. Significant differences were observed in before-exercise TG value and exercise-induced HOMA-β change, with the AG group having a much higher TG value than the GG group (P ≤ 0.05), and the latter exhibiting a significantly larger before-and-after exercise HOMA-β change than the former (P ≤ 0.05). However, no significant difference was observed between the two groups in before exercise indices of body shape, function and quality, nor in exercise-induced changes of body shape, function, and quality. Findings suggest that Visfatin RS4730153 homozygous GG genotype may effect adjustment of glucose and lipid metabolism in obese children and adolescents by reducing TG levels and increasing insulin sensitivity to exercise. PMID:23289013

Usefulness of cardiotoxicity assessment using calcium transient in human induced pluripotent stem cell-derived cardiomyocytes.

PubMed

Watanabe, Hitoshi; Honda, Yayoi; Deguchi, Jiro; Yamada, Toru; Bando, Kiyoko

2017-01-01

Monitoring dramatic changes in intracellular calcium ion levels during cardiac contraction and relaxation, known as calcium transient, in human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) would be an attractive strategy for assessing compounds on cardiac contractility. In addition, as arrhythmogenic compounds are known to induce characteristic waveform changes in hiPSC-CMs, it is expected that calcium transient would allow evaluation of not only compound-induced effects on cardiac contractility, but also compound arrhythmogenic potential. Using a combination of calcium transient in hiPSC-CMs and a fast kinetic fluorescence imaging detection system, we examined in this study changes in calcium transient waveforms induced by a series of 17 compounds that include positive/negative inotropic agents as well as cardiac ion channel activators/inhibitors. We found that all positive inotropic compounds induced an increase in peak frequency and/or peak amplitude. The effects of a negative inotropic compound could clearly be detected in the presence of a β-adrenergic receptor agonist. Furthermore, most arrhythmogenic compounds raised the ratio of peak decay time to peak rise time (D/R ratio) in calcium transient waveforms. Compound concentrations at which these parameters exceeded cutoff values correlated well with systemic exposure levels at which arrhythmias were reported to be evoked. In conclusion, we believe that peak analysis of calcium transient and determination of D/R ratio are reliable methods for assessing compounds' cardiac contractility and arrhythmogenic potential, respectively. Using these approaches would allow selection of compounds with low cardiotoxic potential at the early stage of drug discovery.

Treadmill exercise alleviates chronic mild stress-induced depression in rats.

PubMed

Lee, Taeck-Hyun; Kim, Kijeong; Shin, Mal-Soon; Kim, Chang-Ju; Lim, Baek-Vin

2015-12-01

Depression is a major cause of disability and one of the most common public health problems. In the present study, antidepressive effect of treadmill exercise on chronic mild stress (CMS)-induced depression in rats was investigated. For this, sucrose intake test, immunohistochemistry for 5-bromo-2'-deoxyuridine, terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling staining, and Western blot analysis for brain-derived neurotrophic factor, cyclic adenosine monophosphate response element binding protein, and endothelial nitric oxide synthase were conducted. Following adaptation to the animal vivarium and two baseline fluid intake tests, the animals were divided into four groups: the control group, the CMS-induced depression group, the CMS-induced depression and exercise group, and the CMS-induced depression and fluoxetine-treated group. The animals in the CMS groups were exposed to the CMS conditions for 8 weeks and those in the control group were exposed to the control conditions for 8 weeks. After 4 weeks of CMS, the rats in the CMS-induced depression and exercise group were made to run on a motorized treadmill for 30 min once a day for 4 weeks. In the present results, treadmill exercise alleviated CMS-induced depressive symptoms. Treadmill exercise restored sucrose consumption, increased cell proliferation, and decreased apoptotic cell death. The present results suggest the possibility that exercise may improve symptoms of depression.

Longitudinal changes in reproductive hormones and menstrual cyclicity in cynomolgus monkeys during strenuous exercise training: abrupt transition to exercise-induced amenorrhea.

PubMed

Williams, N I; Caston-Balderrama, A L; Helmreich, D L; Parfitt, D B; Nosbisch, C; Cameron, J L

2001-06-01

Cross-sectional studies of exercise-induced reproductive dysfunction have documented a high proportion of menstrual cycle disturbances in women involved in strenuous exercise training. However, longitudinal studies have been needed to examine individual susceptibility to exercise-induced reproductive dysfunction and to elucidate the progression of changes in reproductive function that occur with strenuous exercise training. Using the female cynomolgus monkey (Macaca fascicularis), we documented changes in menstrual cyclicity and patterns of LH, FSH, estradiol, and progesterone secretion as the animals developed exercise-induced amenorrhea. As monkeys gradually increased running to 12.3 +/- 0.9 km/day, body weight did not change significantly although food intake remained constant. The time spent training until amenorrhea developed varied widely among animals (7-24 months; mean = 14.3 +/- 2.2 months) and was not correlated with initial body weight, training distance, or food intake. Consistent changes in function of the reproductive axis occurred abruptly, one to two menstrual cycles before the development of amenorrhea. These included significant declines in plasma reproductive hormone concentrations, an increase in follicular phase length, and a decrease in luteal phase progesterone secretion. These data document a high level of interindividual variability in the development of exercise-induced reproductive dysfunction, delineate the progression of changes in reproductive hormone secretion that occur with exercise training, and illustrate an abrupt transition from normal cyclicity to an amenorrheic state in exercising individuals, that is not necessarily associated with weight loss.

Physical exercise ameliorates mood disorder-like behavior on high fat diet-induced obesity in mice.

PubMed

Park, Hye-Sang; Lee, Jae-Min; Cho, Han-Sam; Park, Sang-Seo; Kim, Tae-Woon

2017-04-01

Obesity is associated with mood disorders such as depression and anxiety. The aim of this study was to investigate whether treadmill exercise had any benefits on mood disorder by high fat diet (HFD) induced obesity. Mice were randomly divided into four groups: control, control and exercise, high fat diet (HFD), and HFD and exercise. Obesity was induced by a 20-week HFD (60%). In the exercise groups, exercise was performed 6 times a week for 12 weeks, with the exercise duration and intensity gradually increasing at 4-week intervals. Mice were tested in tail suspension and elevated plus maze tasks in order to verify the mood disorder like behavior such as depression and anxiety on obesity. In the present study, the number of 5-HT- and TPH-positive cells, and expression of 5-HT 1A and 5-HTT protein decreased in dorsal raphe, and depression and anxiety like behavior increased in HFD group compared with the CON group. In contrast, treadmill exercise ameliorated mood disorder like behavior by HFD induced obesity and enhanced expression of the serotonergic system in the dorsal raphe. We concluded that exercise increases the capacity of the serotonergic system in the dorsal raphe, which improves the mood disorders associated with HFD-induced obesity. Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.

Involvement of mesolimbic dopaminergic network in neuropathic pain relief by treadmill exercise: A study for specific neural control with Gi-DREADD in mice.

PubMed

Wakaizumi, Kenta; Kondo, Takashige; Hamada, Yusuke; Narita, Michiko; Kawabe, Rui; Narita, Hiroki; Watanabe, Moe; Kato, Shigeki; Senba, Emiko; Kobayashi, Kazuto; Kuzumaki, Naoko; Yamanaka, Akihiro; Morisaki, Hiroshi; Narita, Minoru

2016-01-01

Exercise alleviates pain and it is a central component of treatment strategy for chronic pain in clinical setting. However, little is known about mechanism of this exercise-induced hypoalgesia. The mesolimbic dopaminergic network plays a role in positive emotions to rewards including motivation and pleasure. Pain negatively modulates these emotions, but appropriate exercise is considered to activate the dopaminergic network. We investigated possible involvement of this network as a mechanism of exercise-induced hypoalgesia. In the present study, we developed a protocol of treadmill exercise, which was able to recover pain threshold under partial sciatic nerve ligation in mice, and investigated involvement of the dopaminergic reward network in exercise-induced hypoalgesia. To temporally suppress a neural activation during exercise, a genetically modified inhibitory G-protein-coupled receptor, hM4Di, was specifically expressed on dopaminergic pathway from the ventral tegmental area to the nucleus accumbens. The chemogenetic-specific neural suppression by Gi-DREADD system dramatically offset the effect of exercise-induced hypoalgesia in transgenic mice with hM4Di expressed on the ventral tegmental area dopamine neurons. Additionally, anti-exercise-induced hypoalgesia effect was significantly observed under the suppression of neurons projecting out of the ventral tegmental area to the nucleus accumbens as well. Our findings suggest that the dopaminergic pathway from the ventral tegmental area to the nucleus accumbens is involved in the anti-nociception under low-intensity exercise under a neuropathic pain-like state. © The Author(s) 2016.

Physical exercise-induced changes in the core body temperature of mice depend more on ambient temperature than on exercise protocol or intensity

NASA Astrophysics Data System (ADS)

Wanner, Samuel Penna; Costa, Kátia Anunciação; Soares, Anne Danieli Nascimento; Cardoso, Valbert Nascimento; Coimbra, Cândido Celso

2014-08-01

The mechanisms underlying physical exercise-induced hyperthermia may be species specific. Therefore, the present study aimed to investigate the effects of exercise intensity and ambient temperature on the core body temperature ( T core) of running mice, which provide an important experimental model for advancing the understanding of thermal physiology. We evaluated the influence of different protocols (constant- or incremental-speed exercises), treadmill speeds and ambient temperatures ( T a) on the magnitude of exercise-induced hyperthermia. To measure T core, a telemetric sensor was implanted in the abdominal cavity of male adult Swiss mice under anesthesia. After recovering from the surgery, the animals were familiarized to running on a treadmill and then subjected to the different running protocols and speeds at two T a: 24 °C or 34 °C. All of the experimental trials resulted in marked increases in T core. As expected, the higher-temperature environment increased the magnitude of running-induced hyperthermia. For example, during incremental exercise at 34 °C, the maximal T core achieved was increased by 1.2 °C relative to the value reached at 24 °C. However, at the same T a, neither treadmill speed nor exercise protocol altered the magnitude of exercise-induced hyperthermia. We conclude that T core of running mice is influenced greatly by T a, but not by the exercise protocols or intensities examined in the present report. These findings suggest that the magnitude of hyperthermia in running mice may be regulated centrally, independently of exercise intensity.

Exercise-Induced Neuroprotection of the Nigrostriatal Dopamine System in Parkinson's Disease

PubMed Central

Hou, Lijuan; Chen, Wei; Liu, Xiaoli; Qiao, Decai; Zhou, Fu-Ming

2017-01-01

Epidemiological studies indicate that physical activity and exercise may reduce the risk of developing Parkinson's disease (PD), and clinical observations suggest that physical exercise can reduce the motor symptoms in PD patients. In experimental animals, a profound observation is that exercise of appropriate timing, duration, and intensity can reduce toxin-induced lesion of the nigrostriatal dopamine (DA) system in animal PD models, although negative results have also been reported, potentially due to inappropriate timing and intensity of the exercise regimen. Exercise may also minimize DA denervation-induced medium spiny neuron (MSN) dendritic atrophy and other abnormalities such as enlarged corticostriatal synapse and abnormal MSN excitability and spiking activity. Taken together, epidemiological studies, clinical observations, and animal research indicate that appropriately dosed physical activity and exercise may not only reduce the risk of developing PD in vulnerable populations but also benefit PD patients by potentially protecting the residual DA neurons or directly restoring the dysfunctional cortico-basal ganglia motor control circuit, and these benefits may be mediated by exercise-triggered production of endogenous neuroprotective molecules such as neurotrophic factors. Thus, exercise is a universally available, side effect-free medicine that should be prescribed to vulnerable populations as a preventive measure and to PD patients as a component of treatment. Future research needs to establish standardized exercise protocols that can reliably induce DA neuron protection, enabling the delineation of the underlying cellular and molecular mechanisms that in turn can maximize exercise-induced neuroprotection and neurorestoration in animal PD models and eventually in PD patients. PMID:29163139

Physical exercise-induced changes in the core body temperature of mice depend more on ambient temperature than on exercise protocol or intensity.

PubMed

Wanner, Samuel Penna; Costa, Kátia Anunciação; Soares, Anne Danieli Nascimento; Cardoso, Valbert Nascimento; Coimbra, Cândido Celso

2014-08-01

The mechanisms underlying physical exercise-induced hyperthermia may be species specific. Therefore, the present study aimed to investigate the effects of exercise intensity and ambient temperature on the core body temperature (T core) of running mice, which provide an important experimental model for advancing the understanding of thermal physiology. We evaluated the influence of different protocols (constant- or incremental-speed exercises), treadmill speeds and ambient temperatures (T a) on the magnitude of exercise-induced hyperthermia. To measure T core, a telemetric sensor was implanted in the abdominal cavity of male adult Swiss mice under anesthesia. After recovering from the surgery, the animals were familiarized to running on a treadmill and then subjected to the different running protocols and speeds at two T a: 24 °C or 34 °C. All of the experimental trials resulted in marked increases in T core. As expected, the higher-temperature environment increased the magnitude of running-induced hyperthermia. For example, during incremental exercise at 34 °C, the maximal T core achieved was increased by 1.2 °C relative to the value reached at 24 °C. However, at the same T a, neither treadmill speed nor exercise protocol altered the magnitude of exercise-induced hyperthermia. We conclude that T core of running mice is influenced greatly by T a, but not by the exercise protocols or intensities examined in the present report. These findings suggest that the magnitude of hyperthermia in running mice may be regulated centrally, independently of exercise intensity.

Influence of exercise induced hyperlactatemia on retinal blood flow during normo- and hyperglycemia.

PubMed

Garhöfer, Gerhard; Kopf, Andreas; Polska, Elzbieta; Malec, Magdalena; Dorner, Guido T; Wolzt, Michael; Schmetterer, Leopold

2004-05-01

Short term hyperglycemia has previously been shown to induce a blood flow increase in the retina. The mechanism behind this effect is poorly understood. We set out to investigate whether exercise-induced hyperlactatemia may alter the response of retinal blood flow to hyperglycemia. We performed a randomized, controlled two-way cross over study comprising 12 healthy subjects, performed a 6-minutes period of dynamic exercise during an euglcaemic or hyperglycaemic insulin clamp. Retinal blood flow was assessed by combined vessel size measurement with the Zeiss retinal vessel analyzer and measurement of red blood cell velocities using bi-directional laser Doppler velocimetry. Retinal and systemic hemodynamic parameters were measured before, immediately after and 10 and 20 minutes after isometric exercise. On the euglycemic study day retinal blood flow increased after dynamic exercise. The maximum increase in retinal blood flow was observed 10 minutes after the end of exercise when lactate plasma concentration peaked. Hyperglycemia increased retinal blood flow under basal conditions, but had no incremental effect during exercise induced hyperlactatemia. Our results indicate that both lactate and glucose induce an increase in retinal blood flow in healthy humans. This may indicate a common pathway between glucose and lactate induced blood flow changes in the human retina.

Blood rheology effect of submaximal exercise on young subjects.

PubMed

Romagnoli, Marco; Alis, Rafael; Martinez-Bello, Vladimir; Sanchis-Gomar, Fabian; Aranda, Rafael; Gómez-Cabrera, Mari-Carmen

2014-01-01

Nowadays cardiac and metabolic diseases are a matter of concern. Exercise is a valid treatment and method of prevention for not only adults, but also young subjects. Physical activity causes transient blood rheology impairment in adults. However little is known about the effects of exercise on blood flow characteristics in young subjects. The aim of the study was to assess the effects of a light aerobic exercise session on blood rheology in young subjects. Ten young subjects (aged 12-16 years) performed 1 hour of submaximal aerobic exercise (70% HRmax). Blood samples were drawn just before and after exercise. We determined blood and plasma viscosity, fibrinogen, erythrocyte deformability and aggregability. No changes in blood viscosity (p > 0.05), erythrocyte aggregation (p > 0.05) and fibrinogen (p > 0.05) were observed. Hematocrit (p = 0.025) and plasma viscosity (p = 0.018) rose with exercise, while erythrocyte elongation index lowered (p < 0.001). Plasma volume slightly reduced which may explain the lack of changes in blood viscosity. The results of the present study indicate a similar hemorheological response to submaximal exercise in both young people and adults.

In Vivo, Fatty Acid Translocase (CD36) Critically Regulates Skeletal Muscle Fuel Selection, Exercise Performance, and Training-induced Adaptation of Fatty Acid Oxidation*

PubMed Central

McFarlan, Jay T.; Yoshida, Yuko; Jain, Swati S.; Han, Xioa-Xia; Snook, Laelie A.; Lally, James; Smith, Brennan K.; Glatz, Jan F. C.; Luiken, Joost J. F. P.; Sayer, Ryan A.; Tupling, A. Russell; Chabowski, Adrian; Holloway, Graham P.; Bonen, Arend

2012-01-01

For ∼40 years it has been widely accepted that (i) the exercise-induced increase in muscle fatty acid oxidation (FAO) is dependent on the increased delivery of circulating fatty acids, and (ii) exercise training-induced FAO up-regulation is largely attributable to muscle mitochondrial biogenesis. These long standing concepts were developed prior to the recent recognition that fatty acid entry into muscle occurs via a regulatable sarcolemmal CD36-mediated mechanism. We examined the role of CD36 in muscle fuel selection under basal conditions, during a metabolic challenge (exercise), and after exercise training. We also investigated whether CD36 overexpression, independent of mitochondrial changes, mimicked exercise training-induced FAO up-regulation. Under basal conditions CD36-KO versus WT mice displayed reduced fatty acid transport (−21%) and oxidation (−25%), intramuscular lipids (less than or equal to −31%), and hepatic glycogen (−20%); but muscle glycogen, VO2max, and mitochondrial content and enzymes did not differ. In acutely exercised (78% VO2max) CD36-KO mice, fatty acid transport (−41%), oxidation (−37%), and exercise duration (−44%) were reduced, whereas muscle and hepatic glycogen depletions were accelerated by 27–55%, revealing 2-fold greater carbohydrate use. Exercise training increased mtDNA and β-hydroxyacyl-CoA dehydrogenase similarly in WT and CD36-KO muscles, but FAO was increased only in WT muscle (+90%). Comparable CD36 increases, induced by exercise training (+44%) or by CD36 overexpression (+41%), increased FAO similarly (84–90%), either when mitochondrial biogenesis and FAO enzymes were up-regulated (exercise training) or when these were unaltered (CD36 overexpression). Thus, sarcolemmal CD36 has a key role in muscle fuel selection, exercise performance, and training-induced muscle FAO adaptation, challenging long held views of mechanisms involved in acute and adaptive regulation of muscle FAO. PMID:22584574

Influence of vitamin C and vitamin E on redox signaling: Implications for exercise adaptations.

PubMed

Cobley, James N; McHardy, Helen; Morton, James P; Nikolaidis, Michalis G; Close, Graeme L

2015-07-01

The exogenous antioxidants vitamin C (ascorbate) and vitamin E (α-tocopherol) often blunt favorable cell signaling responses to exercise, suggesting that redox signaling contributes to exercise adaptations. Current theories posit that this antioxidant paradigm interferes with redox signaling by attenuating exercise-induced reactive oxygen species (ROS) and reactive nitrogen species (RNS) generation. The well-documented in vitro antioxidant actions of ascorbate and α-tocopherol and characterization of the type and source of the ROS/RNS produced during exercise theoretically enable identification of redox-dependent mechanisms responsible for the blunting of favorable cell signaling responses to exercise. This review aimed to apply this reasoning to determine how the aforementioned antioxidants might attenuate exercise-induced ROS/RNS production. The principal outcomes of this analysis are (1) neither antioxidant is likely to attenuate nitric oxide signaling either directly (reaction with nitric oxide) or indirectly (reaction with derivatives, e.g., peroxynitrite); (2) neither antioxidant reacts appreciably with hydrogen peroxide, a key effector of redox signaling; (3) ascorbate but not α-tocopherol has the capacity to attenuate exercise-induced superoxide generation; and (4) alternate mechanisms, namely pro-oxidant side reactions and/or reduction of bioactive oxidized macromolecule adducts, are unlikely to interfere with exercise-induced redox signaling. Out of all the possibilities considered, ascorbate-mediated suppression of superoxide generation with attendant implications for hydrogen peroxide signaling is arguably the most cogent explanation for blunting of favorable cell signaling responses to exercise. However, this mechanism is dependent on ascorbate accumulating at sites rich in NADPH oxidases, principal contributors to contraction-mediated superoxide generation, and outcompeting nitric oxide and superoxide dismutase isoforms. The major conclusions of this review are: (1) direct evidence for interference of ascorbate and α-tocopherol with exercise-induced ROS/RNS production is lacking; (2) theoretical analysis reveals that both antioxidants are unlikely to have a major impact on exercise-induced redox signaling; and (3) it is worth considering alternate redox-independent mechanisms. Copyright © 2015 Elsevier Inc. All rights reserved.

Familial Paroxysmal Exercise-Induced Dystonia: Atypical Presentation of Autosomal Dominant GTP-Cyclohydrolase 1 Deficiency

ERIC Educational Resources Information Center

Dale, Russell C.; Melchers, Anna; Fung, Victor S. C.; Grattan-Smith, Padraic; Houlden, Henry; Earl, John

2010-01-01

Paroxysmal exercise-induced dystonia (PED) is one of the rarer forms of paroxysmal dyskinesia, and can occur in sporadic or familial forms. We report a family (male index case, mother and maternal grandfather) with autosomal dominant inheritance of paroxysmal exercise-induced dystonia. The dystonia began in childhood and was only ever induced…

Increases in core temperature counterbalance effects of haemoconcentration on blood viscosity during prolonged exercise in the heat.

PubMed

Buono, Michael J; Krippes, Taylor; Kolkhorst, Fred W; Williams, Alexander T; Cabrales, Pedro

2016-02-01

What is the central question of this study? The purpose of the present study was to determine the effects of exercise-induced haemoconcentration and hyperthermia on blood viscosity. What is the main finding and its importance? Exercise-induced haemoconcentration, increased plasma viscosity and increased blood aggregation, all of which increased blood viscosity, were counterbalanced by increased red blood cell (RBC) deformability (e.g. RBC membrane shear elastic modulus and elongation index) caused by the hyperthermia. Thus, blood viscosity remained unchanged following prolonged moderate-intensity exercise in the heat. Previous studies have reported that blood viscosity is significantly increased following exercise. However, these studies measured both pre- and postexercise blood viscosity at 37 °C even though core and blood temperatures would be expected to have increased during the exercise. Consequently, the effect of exercise-induced hyperthermia on mitigating change in blood viscosity may have been missed. The purpose of this study was to isolate the effects of exercise-induced haemoconcentration and hyperthermia and to determine their combined effects on blood viscosity. Nine subjects performed 2 h of moderate-intensity exercise in the heat (37 °C, 40% relative humidity), which resulted in significant increases from pre-exercise values for rectal temperature (from 37.11 ± 0.35 to 38.76 ± 0.13 °C), haemoconcentration (haematocrit increased from 43.6 ± 3.6 to 45.6 ± 3.5%) and dehydration (change in body weight = -3.6 ± 0.7%). Exercise-induced haemoconcentration significantly (P < 0.05) increased blood viscosity by 9% (from 3.97 to 4.33 cP at 300 s(-1)), whereas exercise-induced hyperthermia significantly decreased blood viscosity by 7% (from 3.97 to 3.69 cP at 300 s(-1)). When both factors were considered together, there was no overall change in blood viscosity (from 3.97 to 4.03 cP at 300 s(-1)). The effects of exercise-induced haemoconcentration, increased plasma viscosity and increased red blood cell aggregation, all of which increased blood viscosity, were counterbalanced by increased red blood cell deformability (e.g. red blood cell membrane shear elastic modulus and elongation index) caused by the hyperthermia. Thus, blood viscosity remained unchanged following prolonged moderate-intensity exercise in the heat. © 2015 The Authors. Experimental Physiology © 2015 The Physiological Society.

Effects of contraction duration on low-frequency fatigue in voluntary and electrically induced exercise of quadriceps muscle in humans.

PubMed

Ratkevicius, A; Skurvydas, A; Povilonis, E; Quistorff, B; Lexell, J

1998-04-01

The aims of this study were to investigate if low-frequency fatigue (LFF) dependent on the duration of repeated muscle contractions and to compare LFF in voluntary and electrically induced exercise. Male subjects performed three 9-min periods of repeated isometric knee extensions at 40% maximal voluntary contraction with contraction plus relaxation periods of 30 plus 60 s, 15 plus 30 s and 5 plus 10 s in protocols 1, 2 and 3, respectively. The same exercise protocols were repeated using feedback-controlled electrical stimulation at 40% maximal tetanic torque. Before and 15 min after each exercise period, knee extension torque at 1, 7, 10, 15, 20, 50 and 100 Hz was assessed. During voluntary exercise, electromyogram root mean square (EMGrms) of the vastus lateralis muscle was evaluated. The 20-Hz torque:100-Hz torque (20:100 Hz torque) ratio was reduced more after electrically induced than after voluntary exercise (P < 0.05). During electrically induced exercise, the decrease in 20:100 Hz torque ratio was gradually (P < 0.05) reduced as the individual contractions shortened. During voluntary exercise, the decrease in 20:100 Hz torque ratio and the increase in EMGrms were greater in protocol 1 (P < 0.01) than in protocols 2 and 3, which did not differ from each other. In conclusion, our results showed that LFF is dependent on the duration of individual muscle contractions during repetitive isometric exercise and that the electrically induced exercise produced a more pronounced LFF compared to voluntary exercise of submaximal intensity. It is suggested that compensatory recruitment of faster-contracting motor units is an additional factor affecting the severity of LFF during voluntary exercise.

Exercise attenuates negative effects of abstinence during 72 hours of smoking deprivation.

PubMed

Conklin, Cynthia A; Soreca, Isabella; Kupfer, David J; Cheng, Yu; Salkeld, Ronald P; Mumma, Joel M; Jakicic, John M; Joyce, Christopher J

2017-08-01

Exercise is presumed to be a potentially helpful smoking cessation adjunct reputed to attenuate the negative effects of deprivation. The present study examined the effectiveness of moderate within-session exercise to reduce 4 key symptoms of smoking deprivation during 3 72-hr nicotine abstinence blocks in both male and female smokers. Forty-nine (25 male, 24 female) sedentary smokers abstained from smoking for 3 consecutive days on 3 separate occasions. At each session, smokers' abstinence-induced craving, cue-induced craving, negative mood, and withdrawal symptom severity were assessed prior to and after either exercise (a.m. exercise, p.m. exercise) or a sedentary control activity (magazine reading). Abstinence-induced craving and negative mood differed as a function of condition, F(2, 385) = 21, p < .0001; and, F(2, 385) = 3.38, p = .03. Planned contrasts revealed no difference between a.m. and p.m. exercise, but exercise overall led to greater pre-post reduction in abstinence-induced craving, t(385) = 6.23, p < .0001, effect size Cohen's d = 0.64; and negative mood, t(385) = 2.25, p = .03, d = 0.23. Overall exercise also led to a larger pre-post reduction in cue-induced craving in response to smoking cues, F(2, 387) = 8.94, p = .0002; and withdrawal severity, F(2, 385) = 3.8, p = .02. Unlike the other 3 measures, p.m. exercise reduced withdrawal severity over control, t(385) = 2.64, p = .009, d = 0.27, whereas a.m. exercise did not. The results support the clinical potential of exercise to assist smokers in managing common and robust negative symptoms experienced during the first 3 days of abstinence. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

INCREASES IN CORE TEMPERATURE COUNTERBALANCE EFFECTS OF HEMOCONCENTRATION ON BLOOD VISCOSITY DURING PROLONGED EXERCISE IN THE HEAT

PubMed Central

Buono, Michael J.; Krippes, Taylor; Kolkhorst, Fred W.; Williams, Alexander T.; Cabrales, Pedro

2015-01-01

Previous studies have reported that blood viscosity is significantly increased following exercise. However, these studies measured both pre- and post-exercise blood viscosity at 37 °C even though core and blood temperatures would be expected to have increased during the exercise. Consequently, the effect of exercise-induced hyperthermia on mitigating change in blood viscosity may have been missed. The purpose of this study was to isolate the effects of exercise-induced hemoconcentration and hyperthermia, as well as determine their combined effects, on blood viscosity. Nine subjects performed 2 h of moderate-intensity exercise in the heat (37 °C, 40% rH), which resulted in significant increases from pre-exercise values for rectal temperature (37.11 ± 0.35 °C to 38.76 ± 0.13 °C), hemoconcentration (hematocrit = 43.6 ± 3.6% to 45.6 ± 3.5%), and dehydration (Δbody weight = −3.6 ± 0.7%). Exercise-induced hemoconcentration significantly (P < 0.05) increased blood viscosity by 9% (3.97 to 4.30 cP at 300 s−1) while exercise-induced hyperthermia significantly decreased blood viscosity by 7% (3.97 to 3.70 cP at 300 s−1). However, when both factors were considered together, there was no overall change in blood viscosity (3.97 to 4.03 cP at 300 s−1). The effects of exercise-induced hemoconcentration, increased plasma viscosity, and increased red blood cell aggregation, all of which increased blood viscosity, were counterbalanced by increased RBC deformability (e.g., RBC membrane shear elastic modulus and elongation index) caused by the hyperthermia. Thus, blood viscosity remained unchanged following prolonged moderate-intensity exercise in the heat. PMID:26682653

Treadmill exercise alleviates nigrostriatal dopaminergic loss of neurons and fibers in rotenone-induced Parkinson rats.

PubMed

Shin, Mal-Soon; Kim, Tae-Woon; Lee, Jae-Min; Ji, Eun-Sang; Lim, Baek-Vin

2017-02-01

Parkinson disease is one of the common brain diseases caused by dopaminergic neuronal loss in the substantia nigra and dopaminergic fiber loss in the striatum. In the present study, the effects of treadmill exercise on motor performance, dopaminergic loss of neurons and fibers, and α-synuclein expression in the nigrostriatum were evaluated using rotenone-induced Parkinson rats. For the induction of Parkinson rats, 3-mg/kg rotenone was injected, once a day for 14 consecutive days. Treadmill running was conducted for 30 min once a day during 14 consecutive days. Rota-rod test for motor balance and coordination and immunohistochemistry for tyrosine hydroxylase and α-synuclein in the nigrostriatum were performed. In the present study, motor balance and coordination was disturbed by induction of rotenone-induced Parkinson disease, in contrast, treadmill exercise alleviated motor dysfunction in the rotenone-induced Parkinson rats. Nigrostriatal dopaminergic loss of neurons and fibers was occurred by induction of rotenone-induced Parkinson disease, in contrast, treadmill exercise alleviated nigrostriatal dopaminergic loss of neurons and fibers in the rotenone-induced Parkinson rats. α-Synuclein expression in the nigrostriatum was enhanced by induction of rotenone-induced Parkinson disease, in contrast, treadmill exercise suppressed α-synuclein expression in the rotenone-induced Parkinson rats. Treadmill exercise improved motor function through preservation of nigrostriatal dopaminergic neurons and fibers and suppression of nigrostriatal formation of Lewy bodies in rotenone-induced Parkinson rats.

Vitamin E and vitamin C do not reduce insulin sensitivity but inhibit mitochondrial protein expression in exercising obese rats

PubMed Central

Picklo, Matthew J.; Thyfault, John P.

2016-01-01

Controversy exists as to whether supplementation with the antioxidants vitamin E and vitamin C blocks adaptation to exercise. Exercise is a first-line means to treat obesity and its complications. While diet-induced obesity alters mitochondrial function and induces insulin resistance (IR), no data exist as to whether supplementation with vitamin E and vitamin C modify responses to exercise in pre-existing obesity. We tested the hypothesis that dietary supplementation with vitamin E (0.4 g α-tocopherol acetate/kg) and vitamin C (0.5 g/kg) blocks exercise-induced improvements on IR and mitochondrial content in obese rats maintained on a high-fat (45% fat energy (en)) diet. Diet-induced obese, sedentary rats had a 2-fold higher homeostasis model assessment of insulin resistance and larger insulin area under the curve following glucose tolerances test than rats fed a low-fat (10% fat en) diet. Exercising (12 weeks at 5 times per week in a motorized wheel) of obese rats normalized IR indices, an effect not modified by vitamin E and vitamin C. Vitamin E and vitamin C supplementation with exercise elevated mtDNA content in adipose and skeletal muscle to a greater extent (20%) than exercise alone in a depot-specific manner. On the other hand, vitamin C and vitamin E decreased exercise-induced increases in mitochondrial protein content for complex I (40%) and nicotinamide nucleotide transhydrogenase (35%) in a muscle-dependent manner. These data indicate that vitamin E and vitamin C supplementation in obese rodents does not modify exercise-induced improvements in insulin sensitivity but that changes in mitochondrial biogenesis and mitochondrial protein expression may be modified by antioxidant supplementation. PMID:25761734

Exercise prevents high fat diet-induced bone loss, marrow adiposity and dysbiosis in male mice.

PubMed

McCabe, Laura R; Irwin, Regina; Tekalur, Arjun; Evans, Christian; Schepper, Jonathan D; Parameswaran, Narayanan; Ciancio, Mae

2018-03-29

High fat diets can have detrimental effects on the skeleton as well as cause intestinal dysbiosis. Exercise prevents high fat (HF) diet-induced obesity and also improves bone density and prevents the intestinal dysbiosis that promotes energy storage. Previous studies indicate a link between intestinal microbial balance and bone health. Therefore, we examined whether exercise could prevent HF-induced bone pathology in male mice and determined whether benefits correlate to changes in host intestinal microbiota. Male C57Bl/6 mice were fed either a low fat diet (LF; 10 kcal% fat) or a HF diet (60 kcal% fat) and put under sedentary or voluntary exercise conditions for 14 weeks. Our results indicated that HF diet reduced trabecular bone volume, when corrected for differences in body weight, of both the tibia (40% reduction) and vertebrae (25% reduction) as well and increased marrow adiposity (44% increase). More importantly, these effects were prevented by exercise. Exercise also had a significant effect on several cortical bone parameters and enhanced bone mechanical properties in LF but not HF fed mice. Microbiome analyses indicated that exercise altered the HF induced changes in microbial composition by reducing the Firmicutes/Bacteriodetes ratio. This ratio negatively correlated with bone volume as did levels of Clostridia and Lachnospiraceae. In contrast, the abundance of several Actinobacteria phylum members (i.e., Bifidobacteriaceae) were positively correlated with bone volume. Taken together, exercise can prevent many of the negative effects of a high fat diet on male skeletal health. Exercise induced changes in microbiota composition could represent a novel mechanism that contributes to exercise induced benefits to bone health. Copyright © 2018 Elsevier Inc. All rights reserved.

High-intensity exercise training increases the diversity and metabolic capacity of the mouse distal gut microbiota during diet-induced obesity

PubMed Central

Denou, Emmanuel; Marcinko, Katarina; Surette, Michael G.; Steinberg, Gregory R.

2016-01-01

Diet and exercise underpin the risk of obesity-related metabolic disease. Diet alters the gut microbiota, which contributes to aspects of metabolic disease during obesity. Repeated exercise provides metabolic benefits during obesity. We assessed whether exercise could oppose changes in the taxonomic and predicted metagenomic characteristics of the gut microbiota during diet-induced obesity. We hypothesized that high-intensity interval training (HIIT) would counteract high-fat diet (HFD)-induced changes in the microbiota without altering obesity in mice. Compared with chow-fed mice, an obesity-causing HFD decreased the Bacteroidetes-to-Firmicutes ratio and decreased the genetic capacity in the fecal microbiota for metabolic pathways such as the tricarboxylic acid (TCA) cycle. After HFD-induced obesity was established, a subset of mice were HIIT for 6 wk, which increased host aerobic capacity but did not alter body or adipose tissue mass. The effects of exercise training on the microbiota were gut segment dependent and more extensive in the distal gut. HIIT increased the alpha diversity and Bacteroidetes/Firmicutes ratio of the distal gut and fecal microbiota during diet-induced obesity. Exercise training increased the predicted genetic capacity related to the TCA cycle among other aspects of metabolism. Strikingly, the same microbial metabolism indexes that were increased by exercise were all decreased in HFD-fed vs. chow diet-fed mice. Therefore, exercise training directly opposed some of the obesity-related changes in gut microbiota, including lower metagenomic indexes of metabolism. Some host and microbial pathways appeared similarly affected by exercise. These exercise- and diet-induced microbiota interactions can be captured in feces. PMID:27117007

High-intensity exercise training increases the diversity and metabolic capacity of the mouse distal gut microbiota during diet-induced obesity.

PubMed

Denou, Emmanuel; Marcinko, Katarina; Surette, Michael G; Steinberg, Gregory R; Schertzer, Jonathan D

2016-06-01

Diet and exercise underpin the risk of obesity-related metabolic disease. Diet alters the gut microbiota, which contributes to aspects of metabolic disease during obesity. Repeated exercise provides metabolic benefits during obesity. We assessed whether exercise could oppose changes in the taxonomic and predicted metagenomic characteristics of the gut microbiota during diet-induced obesity. We hypothesized that high-intensity interval training (HIIT) would counteract high-fat diet (HFD)-induced changes in the microbiota without altering obesity in mice. Compared with chow-fed mice, an obesity-causing HFD decreased the Bacteroidetes-to-Firmicutes ratio and decreased the genetic capacity in the fecal microbiota for metabolic pathways such as the tricarboxylic acid (TCA) cycle. After HFD-induced obesity was established, a subset of mice were HIIT for 6 wk, which increased host aerobic capacity but did not alter body or adipose tissue mass. The effects of exercise training on the microbiota were gut segment dependent and more extensive in the distal gut. HIIT increased the alpha diversity and Bacteroidetes/Firmicutes ratio of the distal gut and fecal microbiota during diet-induced obesity. Exercise training increased the predicted genetic capacity related to the TCA cycle among other aspects of metabolism. Strikingly, the same microbial metabolism indexes that were increased by exercise were all decreased in HFD-fed vs. chow diet-fed mice. Therefore, exercise training directly opposed some of the obesity-related changes in gut microbiota, including lower metagenomic indexes of metabolism. Some host and microbial pathways appeared similarly affected by exercise. These exercise- and diet-induced microbiota interactions can be captured in feces. Copyright © 2016 the American Physiological Society.

The Role of Autonomic Function in Exercise-induced Endogenous Analgesia: A Case-control Study in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome and Healthy People.

PubMed

Oosterwijck, Jessica Van; Marusic, Uros; De Wandele, Inge; Paul, Lorna; Meeus, Mira; Moorkens, Greta; Lambrecht, Luc; Danneels, Lieven; Nijs, Jo

2017-03-01

Patients with myalgic encephalomyelitis / chronic fatigue syndrome (ME/CFS) are unable to activate brain-orchestrated endogenous analgesia (or descending inhibition) in response to exercise. This physiological impairment is currently regarded as one factor explaining post-exertional malaise in these patients. Autonomic dysfunction is also a feature of ME/CFS. This study aims to examine the role of the autonomic nervous system in exercise-induced analgesia in healthy people and those with ME/CFS, by studying the recovery of autonomic parameters following aerobic exercise and the relation to changes in self-reported pain intensity. A controlled experimental study. The study was conducted at the Human Physiology lab of a University. Twenty women with ME/CFS- and 20 healthy, sedentary controls performed a submaximal bicycle exercise test known as the Aerobic Power Index with continuous cardiorespiratory monitoring. Before and after the exercise, measures of autonomic function (i.e., heart rate variability, blood pressure, and respiration rate) were performed continuously for 10 minutes and self-reported pain levels were registered. The relation between autonomous parameters and self-reported pain parameters was examined using correlation analysis. Some relationships of moderate strength between autonomic and pain measures were found. The change (post-exercise minus pre-exercise score) in pain severity was correlated (r = .580, P = .007) with the change in diastolic blood pressure in the healthy group. In the ME/CFS group, positive correlations between the changes in pain severity and low frequency (r = .552, P = .014), and between the changes in bodily pain and diastolic blood pressure (r = .472, P = .036), were seen. In addition, in ME/CHFS the change in headache severity was inversely correlated (r = -.480, P = .038) with the change in high frequency heart rate variability. Based on the cross-sectional design of the study, no firm conclusions can be drawn on the causality of the relations. Reduced parasympathetic reactivation during recovery from exercise is associated with the dysfunctional exercise-induced analgesia in ME/CFS. Poor recovery of diastolic blood pressure in response to exercise, with blood pressure remaining elevated, is associated with reductions of pain following exercise in ME/CFS, suggesting a role for the arterial baroreceptors in explaining dysfunctional exercise-induced analgesia in ME/CFS patients.Key words: Aerobic exercise, aerobic power index, autonomic nervous system, exercise-induced analgesia, exercise-induced hypoalgesia, fibromyalgia, heart rate variability, stress-induced analgesia, pain.

Influence of menopause status and age on integrated central and peripheral hemodynamic responses to subsystolic cuffing during submaximal exercise

PubMed Central

Gramm, Courtney; Randall, Nicholas R.; Olson, Thomas P.

2016-01-01

Although pathophysiological links between postmenopause and healthy aging remain unclear, both factors are associated with increased blood pressure and sympathetic nerve activity (SNA) in women. Activation of polymodal musculoskeletal neural afferents originating within adventia of venules modulates SNA and blood pressure control during exercise in healthy adults. We hypothesized transient subsystolic regional circulatory occlusion (RCO) during exercise sensitizes these afferents leading to augmented systemic vascular resistance (SVR)-mediated increased mean arterial pressure (MAP) in postmenopause vs. premenopause. Normotensive women in premenopause or postmenopause (n = 14 and 14; ages: 30 ± 9 and 55 ± 7 yr, respectively; P < 0.01) performed: 1) peak exercise testing and 2) fixed-load cycling at 30% peak workload (48 ± 11 and 38 ± 6 W, respectively; P < 0.01), whereby the initial 3 min were control exercise without RCO (CTL), thereafter including 2 min of bilateral-thigh RCO to 20, 40, 60, 80, or 100 mmHg (randomized), with 2 min deflation between RCO. Both MAP (17 ± 4 vs. 4 ± 4%, P = 0.02) and SVR (16 ± 8 vs. −3 ± 8%, P = 0.04) increased at 80 mmHg from CTL in postmenopause vs. premenopause, respectively. However, cardiac index was similar in postmenopause vs. premenopause at 80 mmHg from CTL (1 ± 6 vs. 7 ± 6%, respectively; P = 0.15). There was no continuous effect of aging in MAP (P = 0.12), SVR (P = 0.07), or cardiac index (P = 0.18) models. These data suggest transient locomotor subsystolic RCO sensitizes musculoskeletal afferents, which provoke increased SVR to generate augmented MAP during exercise in postmenopause. These observations provide a novel approach for understanding the age-independent variability in exercise blood pressure control across the normotensive adult pre- to postmenopause spectrum. PMID:27765745

A randomised controlled trial of aerobic exercise after transient ischaemic attack or minor stroke to prevent cognitive decline: the MoveIT study protocol.

PubMed

Boss, H M; Van Schaik, S M; Deijle, I A; de Melker, E C; van den Berg, B T J; Scherder, E J A; Bosboom, W M J; Weinstein, H C; Van den Berg-Vos, R M

2014-12-31

Patients with transient ischaemic attack (TIA) or stroke are at risk for cognitive impairment and dementia. Currently, there is no known effective strategy to prevent this cognitive decline. Increasing evidence exists that physical exercise is beneficial for cognitive function. However, in patients with TIA or stroke who are at risk of cognitive impairment and dementia, only a few trials have been conducted. In this study, we aim to investigate whether a physical exercise programme (MoveIT) can prevent cognitive decline in patients in the acute phase after a TIA or minor ischaemic stroke. A single-blinded randomised controlled trial will be conducted to investigate the effect of an aerobic exercise programme on cognition compared with usual care. 120 adult patients with a TIA or minor ischaemic stroke less than 1 month ago will be randomly allocated to an exercise programme consisting of a 12-week aerobic exercise programme and regular follow-up visits to a specialised physiotherapist during the period of 1 year or to usual care. Outcome measures will be assessed at the baseline, and at the 1-year and 2-year follow-up. The primary outcome is cognitive functioning measured with the Montreal Cognitive Assessment (MoCA) test and with additional neuropsychological tests. Secondary outcomes include maximal exercise capacity, self-reported physical activity and measures of secondary prevention. The study received ethical approval from the VU University Amsterdam Ethics committee (2011/383). The results of this study will be published in peer-reviewed journals and presented at international conferences. We will also disseminate the main results to our participants in a letter. The Nederlands Trial Register NTR3884. 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.

Influence of menopause status and age on integrated central and peripheral hemodynamic responses to subsystolic cuffing during submaximal exercise.

PubMed

Van Iterson, Erik H; Gramm, Courtney; Randall, Nicholas R; Olson, Thomas P

2016-12-01

Although pathophysiological links between postmenopause and healthy aging remain unclear, both factors are associated with increased blood pressure and sympathetic nerve activity (SNA) in women. Activation of polymodal musculoskeletal neural afferents originating within adventia of venules modulates SNA and blood pressure control during exercise in healthy adults. We hypothesized transient subsystolic regional circulatory occlusion (RCO) during exercise sensitizes these afferents leading to augmented systemic vascular resistance (SVR)-mediated increased mean arterial pressure (MAP) in postmenopause vs. premenopause. Normotensive women in premenopause or postmenopause (n = 14 and 14; ages: 30 ± 9 and 55 ± 7 yr, respectively; P < 0.01) performed: 1) peak exercise testing and 2) fixed-load cycling at 30% peak workload (48 ± 11 and 38 ± 6 W, respectively; P < 0.01), whereby the initial 3 min were control exercise without RCO (CTL), thereafter including 2 min of bilateral-thigh RCO to 20, 40, 60, 80, or 100 mmHg (randomized), with 2 min deflation between RCO. Both MAP (17 ± 4 vs. 4 ± 4%, P = 0.02) and SVR (16 ± 8 vs. -3 ± 8%, P = 0.04) increased at 80 mmHg from CTL in postmenopause vs. premenopause, respectively. However, cardiac index was similar in postmenopause vs. premenopause at 80 mmHg from CTL (1 ± 6 vs. 7 ± 6%, respectively; P = 0.15). There was no continuous effect of aging in MAP (P = 0.12), SVR (P = 0.07), or cardiac index (P = 0.18) models. These data suggest transient locomotor subsystolic RCO sensitizes musculoskeletal afferents, which provoke increased SVR to generate augmented MAP during exercise in postmenopause. These observations provide a novel approach for understanding the age-independent variability in exercise blood pressure control across the normotensive adult pre- to postmenopause spectrum. Copyright © 2016 the American Physiological Society.

Single molecular image of cytosolic free Ca2+ of skeletal muscle cells in rats pre- and post-exercise-induced fatigue

NASA Astrophysics Data System (ADS)

Liu, Yi; Zhang, Heming; Zhao, Yanping; Liu, Zhiming

2009-08-01

A growing body of literature indicated the cytosolic free Ca2+ concentration of skeletal muscle cells changes significantly during exercise-induced fatigue. But it is confusing whether cytosolic free Ca2+ concentration increase or decrease. Furthermore, current researches mainly adopt muscle tissue homogenate as experiment material, but the studies based on cellular and subcellular level is seldom. This study is aimed to establish rat skeletal muscle cell model of exercise-induced fatigue, and confirm the change of cytosolic free Ca2+ concentration of skeletal muscle cells in rats preand post- exercise-induced fatigue. In this research, six male Wistar rats were randomly divided into two groups: control group (n=3) and exercise-induced fatigue group (n=3). The former group were allowed to freely move and the latter were forced to loaded swimming to exhaustive. Three days later, all the rats were sacrificed, the muscle tissue from the same site of skeletal muscle were taken out and digested to cells. After primary culture of the two kinds of skeletal muscle cells from tissue, a fluorescent dye-Fluo-3 AM was used to label the cytosolic free Ca2+. The fluorescent of Ca2+ was recorded by confocal laser scanning microscopy. The results indicated that, the Ca2+ fluorescence intensity of cells from the rat of exercise-induced fatigue group was significantly higher than those in control group. In conclusion, cytosolic free Ca2+ concentration of skeletal muscle cells has a close relation with exercise-induced fatigue, and the increase of cytosolic free Ca2+ concentration may be one of the important factors of exercise-induced fatigue.

Exercise-induced circulating extracellular vesicles protect against cardiac ischemia-reperfusion injury.

PubMed

Bei, Yihua; Xu, Tianzhao; Lv, Dongchao; Yu, Pujiao; Xu, Jiahong; Che, Lin; Das, Avash; Tigges, John; Toxavidis, Vassilios; Ghiran, Ionita; Shah, Ravi; Li, Yongqin; Zhang, Yuhui; Das, Saumya; Xiao, Junjie

2017-07-01

Extracellular vesicles (EVs) serve an important function as mediators of intercellular communication. Exercise is protective for the heart, although the signaling mechanisms that mediate this cardioprotection have not been fully elucidated. Here using nano-flow cytometry, we found a rapid increase in plasma EVs in human subjects undergoing exercise stress testing. We subsequently identified that serum EVs were increased by ~1.85-fold in mice after 3-week swimming. Intramyocardial injection of equivalent quantities of EVs from exercised mice and non-exercised controls provided similar protective effects against acute ischemia/reperfusion (I/R) injury in mice. However, injection of exercise-induced EVs in a quantity equivalent to the increase seen with exercise (1.85 swim group) significantly enhanced the protective effect. Similarly, treatment with exercise-induced increased EVs provided additional anti-apoptotic effect in H 2 O 2 -treated H9C2 cardiomyocytes mediated by the activation of ERK1/2 and HSP27 signaling. Finally, by treating H9C2 cells with insulin-like growth factor-1 to mimic exercise stimulus in vitro, we found an increased release of EVs from cardiomyocytes associated with ALIX and RAB35 activation. Collectively, our results show that exercise-induced increase in circulating EVs enhances the protective effects of endogenous EVs against cardiac I/R injury. Exercise-derived EVs might serve as a potent therapy for myocardial injury in the future.

Exercise training starting at weaning age preserves cardiac pacemaker function in adulthood of diet-induced obese rats.

PubMed

Carvalho de Lima, Daniel; Guimarães, Juliana Bohnen; Rodovalho, Gisele Vieira; Silveira, Simonton Andrade; Haibara, Andrea Siqueira; Coimbra, Cândido Celso

2014-08-01

Peripheral sympathetic overdrive in young obese subjects contributes to further aggravation of insulin resistance, diabetes, and hypertension, thus inducing worsening clinical conditions in adulthood. Exercise training has been considered a strategy to repair obesity autonomic dysfunction, thereby reducing the cardiometabolic risk. Therefore, the aim of this study was to assess the effect of early exercise training, starting immediately after weaning, on cardiac autonomic control in diet-induced obese rats. Male Wistar rats (weaning) were divided into four groups: (i) a control group (n = 6); (ii) an exercise-trained control group (n = 6); (iii) a diet-induced obesity group (n = 6); and (iv) an exercise-trained diet-induced obesity group (n = 6). The development of obesity was induced by 9 weeks of palatable diet intake, and the training program was implemented in a motor-driven treadmill (5 times per week) during the same period. After this period, animals were submitted to vein and artery catheter implantation to assess cardiac autonomic balance by methylatropine (3 mg/kg) and propranolol (4 mg/kg) administration. Exercise training increased running performance in both groups (p < 0.05). Exercise training also prevented the increased resting heart rate in obese rats, which seemed to be related to cardiac pacemaker activity preservation (p < 0.05). Additionally, the training program preserved the pressure and bradycardia responses to autonomic blockade in obese rats (p < 0.05). An exercise program beginning at weaning age prevents cardiovascular dysfunction in obese rats, indicating that exercise training may be used as a nonpharmacological therapeutic strategy for the treatment of cardiometabolic diseases.

Maintenance of exercise-induced benefits in physical functioning and bone among elderly women.

PubMed

Karinkanta, S; Heinonen, A; Sievänen, H; Uusi-Rasi, K; Fogelholm, M; Kannus, P

2009-04-01

This study showed that about a half of the exercise-induced gain in dynamic balance and bone strength was maintained one year after cessation of the supervised high-intensity training of home-dwelling elderly women. However, to maintain exercise-induced gains in lower limb muscle force and physical functioning, continued training seems necessary. Maintenance of exercise-induced benefits in physical functioning and bone structure was assessed one year after cessation of 12-month randomized controlled exercise intervention. Originally 149 healthy women 70-78 years of age participated in the 12-month exercise RCT and 120 (81%) of them completed the follow-up study. Self-rated physical functioning, dynamic balance, leg extensor force, and bone structure were assessed. During the intervention, exercise increased dynamic balance by 7% in the combination resistance and balance-jumping training group (COMB). At the follow-up, a 4% (95% CI: 1-8%) gain compared with the controls was still seen, while the exercise-induced isometric leg extension force and self-rated physical functioning benefits had disappeared. During the intervention, at least twice a week trained COMB subjects obtained a significant 2% benefit in tibial shaft bone strength index compared to the controls. A half of this benefit seemed to be maintained at the follow-up. Exercise-induced benefits in dynamic balance and rigidity in the tibial shaft may partly be maintained one year after cessation of a supervised 12-month multi-component training in initially healthy elderly women. However, to maintain the achieved gains in muscle force and physical functioning, continued training seems necessary.

Global Proteome Changes in the Rat Diaphragm Induced by Endurance Exercise Training.

PubMed

Sollanek, Kurt J; Burniston, Jatin G; Kavazis, Andreas N; Morton, Aaron B; Wiggs, Michael P; Ahn, Bumsoo; Smuder, Ashley J; Powers, Scott K

2017-01-01

Mechanical ventilation (MV) is a life-saving intervention for many critically ill patients. Unfortunately, prolonged MV results in the rapid development of diaphragmatic atrophy and weakness. Importantly, endurance exercise training results in a diaphragmatic phenotype that is protected against ventilator-induced diaphragmatic atrophy and weakness. The mechanisms responsible for this exercise-induced protection against ventilator-induced diaphragmatic atrophy remain unknown. Therefore, to investigate exercise-induced changes in diaphragm muscle proteins, we compared the diaphragmatic proteome from sedentary and exercise-trained rats. Specifically, using label-free liquid chromatography-mass spectrometry, we performed a proteomics analysis of both soluble proteins and mitochondrial proteins isolated from diaphragm muscle. The total number of diaphragm proteins profiled in the soluble protein fraction and mitochondrial protein fraction were 813 and 732, respectively. Endurance exercise training significantly (P<0.05, FDR <10%) altered the abundance of 70 proteins in the soluble diaphragm proteome and 25 proteins of the mitochondrial proteome. In particular, key cytoprotective proteins that increased in relative abundance following exercise training included mitochondrial fission process 1 (Mtfp1; MTP18), 3-mercaptopyruvate sulfurtransferase (3MPST), microsomal glutathione S-transferase 3 (Mgst3; GST-III), and heat shock protein 70 kDa protein 1A/1B (HSP70). While these proteins are known to be cytoprotective in several cell types, the cyto-protective roles of these proteins have yet to be fully elucidated in diaphragm muscle fibers. Based upon these important findings, future experiments can now determine which of these diaphragmatic proteins are sufficient and/or required to promote exercise-induced protection against inactivity-induced muscle atrophy.

Psychophysiological effects of massage-myofascial release after exercise: a randomized sham-control study.

PubMed

Arroyo-Morales, Manuel; Olea, Nicolas; Martínez, Marin Manuel; Hidalgo-Lozano, Amparo; Ruiz-Rodríguez, Concepción; Díaz-Rodríguez, Lourdes

2008-12-01

The aim of this study was to evaluate the effect of massage on neuromuscular recruitment, mood state, and mechanical nociceptive threshold (MNT) after high-intensity exercise. This was a prospective randomized clinical trial using between-groups design. The study was conducted at a university-based sports medicine clinic. Sixty-two (62) healthy active students age 18-26 participated. Participants, randomized into two groups, performed three 30-second Wingate tests and immediately received whole-body massage-myofascial induction or placebo (sham ultrasound/magnetotherapy) treatment. The duration (40 minutes), position, and therapist were the same for both treatments. Dependent variables were surface electromyography (sEMG) of quadriceps, profile of mood states (POMS) and mechanical nociceptive threshold (MNT) of trapezius and masseter muscles. These data were assessed at baseline and after exercise and recovery periods. Generalized estimating equations models were performed on dependent variables to assess differences between groups. Significant differences were found in effects of treatment on sEMG of Vastus Medialis (VM) (p = 0.02) and vigor subscale (p = 0.04). After the recovery period, there was a significant decrease in electromyographic (EMG) activity of VM (p = 0.02) in the myofascial-release group versus a nonsignificant increase in the placebo group (p = 0.32), and a decrease in vigor (p < 0.01) in the massage group versus no change in the placebo group (p = 0.86). Massage reduces EMG amplitude and vigor when applied as a passive recovery technique after a high-intensity exercise protocol. Massage may induce a transient loss of muscle strength or a change in the muscle fiber tension-length relationship, influenced by alterations of muscle function and a psychological state of relaxation.

[Exercise-induced rhabdomyolysis - a new trend?

PubMed

Fardal, Hilde; Gøransson, Lasse G

2016-10-01

The purpose of this study was to investigate whether or not there has been an increase in the number of admissions for exercise-induced rhabdomyolysis at Stavanger University Hospital (SUS) in recent years. The study is a retrospective review of patients discharged over the period January 2010 to March 2015 with a diagnosis of exercise-induced rhabdomyolysis and with maximum creatine kinase (CK) levels more than ten times the upper reference limit. A total of 33 patients, 21 women and 12 men, with a median age of 28 years (18 - 68), were included in the study. Of the 33 patients, three quarters (25) were admitted in 2014 - 15, compared with eight over the period 2010 - 13. One patient developed kidney failure that required dialysis. The treatment depended more on the attending physician and department than on the patient's clinical condition and CK-level, but this did not seem to affect the rate of complications. The incidence of exercise-induced rhabdomyolysis at SUS increased from autumn 2014, and this coincided with increased media attention and a new exercise trend. We recommend standardising the treatment of exercise-induced rhabdomyolysis, as current treatment recommendations are based on rhabdomyolysis triggered by causes other than exercise.

Forced rather than voluntary exercise entrains peripheral clocks via a corticosterone/noradrenaline increase in PER2::LUC mice

PubMed Central

Sasaki, Hiroyuki; Hattori, Yuta; Ikeda, Yuko; Kamagata, Mayo; Iwami, Shiho; Yasuda, Shinnosuke; Tahara, Yu; Shibata, Shigenobu

2016-01-01

Exercise during the inactive period can entrain locomotor activity and peripheral circadian clock rhythm in mice; however, mechanisms underlying this entrainment are yet to be elucidated. Here, we showed that the bioluminescence rhythm of peripheral clocks in PER2::LUC mice was strongly entrained by forced treadmill and forced wheel-running exercise rather than by voluntary wheel-running exercise at middle time during the inactivity period. Exercise-induced entrainment was accompanied by increased levels of serum corticosterone and norepinephrine in peripheral tissues, similar to the physical stress-induced response. Adrenalectomy with norepinephrine receptor blockers completely blocked the treadmill exercise-induced entrainment. The entrainment of the peripheral clock by exercise is independent of the suprachiasmatic nucleus clock, the main oscillator in mammals. The present results suggest that the response of forced exercise, but not voluntary exercise, may be similar to that of stress, and possesses the entrainment ability of peripheral clocks through the activation of the adrenal gland and the sympathetic nervous system. PMID:27271267

Exercise excess pressure and exercise-induced albuminuria in patients with type 2 diabetes mellitus.

PubMed

Climie, Rachel E D; Srikanth, Velandai; Keith, Laura J; Davies, Justin E; Sharman, James E

2015-05-01

Exercise-induced albuminuria is common in patients with type 2 diabetes mellitus (T2DM) in response to maximal exercise, but the response to light-moderate exercise is unclear. Patients with T2DM have abnormal central hemodynamics and greater propensity for exercise hypertension. This study sought to determine the relationship between light-moderate exercise central hemodynamics (including aortic reservoir and excess pressure) and exercise-induced albuminuria. Thirty-nine T2DM (62 ± 9 yr; 49% male) and 39 nondiabetic controls (53 ± 9 yr; 51% male) were examined at rest and during 20 min of light-moderate cycle exercise (30 W; 50 revolutions/min). Albuminuria was assessed by the albumin-creatinine ratio (ACR) at rest and 30 min postexercise. Hemodynamics recorded included brachial and central blood pressure (BP), aortic stiffness, augmented pressure (AP), aortic reservoir pressure, and excess pressure integral (Pexcess). There was no difference in ACR between groups before exercise (P > 0.05). Exercise induced a significant rise in ACR in T2DM but not controls (1.73 ± 1.43 vs. 0.53 ± 1.0 mg/mol, P = 0.002). All central hemodynamic variables were significantly higher during exercise in T2DM (i.e., Pexcess, systolic BP and AP; P < 0.01 all). In T2DM (but not controls), exercise Pexcess was associated with postexercise ACR (r = 0.51, P = 0.002), and this relationship was independent of age, sex, body mass index, heart rate, aortic stiffness, antihypertensive medication, and ambulatory daytime systolic BP (β = 0.003, P = 0.003). Light-moderate exercise induced a significant rise in ACR in T2DM, and this was independently associated with Pexcess, a potential marker of vascular dysfunction. These novel findings suggest that Pexcess could be important for appropriate renal function in T2DM. Copyright © 2015 the American Physiological Society.

Laser-induced transient grating setup with continuously tunable period

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vega-Flick, A.; Applied Physics Department, CINVESTAV-Unidad Mérida, Carretera Antigua a Progreso Km 6, Cordemex, Mérida, Yucatán 97310 Mexico; Eliason, J. K.

2015-12-15

We present a modification of the laser-induced transient grating setup enabling continuous tuning of the transient grating period. The fine control of the period is accomplished by varying the angle of the diffraction grating used to split excitation and probe beams. The setup has been tested by measuring dispersion of bulk and surface acoustic waves in both transmission and reflection geometries. The presented modification is fully compatible with optical heterodyne detection and can be easily implemented in any transient grating setup.

Dietary antioxidants and exercise.

PubMed

Powers, Scott K; DeRuisseau, Keith C; Quindry, John; Hamilton, Karyn L

2004-01-01

Muscular exercise promotes the production of radicals and other reactive oxygen species in the working muscle. Growing evidence indicates that reactive oxygen species are responsible for exercise-induced protein oxidation and contribute to muscle fatigue. To protect against exercise-induced oxidative injury, muscle cells contain complex endogenous cellular defence mechanisms (enzymatic and non-enzymatic antioxidants) to eliminate reactive oxygen species. Furthermore, exogenous dietary antioxidants interact with endogenous antioxidants to form a cooperative network of cellular antioxidants. Knowledge that exercise-induced oxidant formation can contribute to muscle fatigue has resulted in numerous investigations examining the effects of antioxidant supplementation on human exercise performance. To date, there is limited evidence that dietary supplementation with antioxidants will improve human performance. Furthermore, it is currently unclear whether regular vigorous exercise increases the need for dietary intake of antioxidants. Clearly, additional research that analyses the antioxidant requirements of individual athletes is needed.

Exercise-induced rhabdomyolysis from stationary biking: a case report.

PubMed

Inklebarger, J; Galanis, N; Kirkos, J; Kapetanos, G

2010-10-01

There are several reports concerning exercise and rabdomyolysis. There has been no report in the English literature of exercise induced rabdomyolisis from a stationary bike.A 63-year-old female recreational athlete presented to our hospital seeking treatment for lower back, leg pain and stiffness after exercising on a stationary bicycle one day prior. Blood work showed a raised CK of 38,120 U/L, a myoglobin of 5330 and an AST 495 U/L with normal urea and electrolytes. Urinalysis remained negative. She was admitted for oral and intravenous hydration and fluid balance monitoringThis is a very rare case of rhabdomyolysis due to exercise. This study highlights the difficulties faced by accident and emergency teams in distinguishing delayed onset muscle soreness (DOMS) from exercise-induced rhabdomyolysis, and reinforces the concept that rhabdomyolysis can occur at any level of exercise intensity.

Exercise-induced rhabdomyolysis.

PubMed

Lee, George

2014-11-03

Exercise-induced rhabdomyolysis, or exertional rhabdomyolysis (ER), is a clinical entity typically considered when someone presents with muscle stiffness, swelling, and pain out of proportion to the expected fatigue post exercise. The diagnosis is confirmed by myoglobinuria, and an elevated serum Creatinine Phosphokinase (CPK) level, usually 10 times the normal range. However, an elevation in CPK is seen in most forms of strenuous exercise, up to 20 times the upper normal range. Therefore, there is no definitive pathologic CPK cut-off. Fortunately the dreaded complication of acute renal failure is rare compared to other forms rhabdomyolysis. We review the risks, diagnosis, clinical course and treatment for exercise- induced rhabdomyolysis.

Plasma electrolytes, pH, and ECG during and after exhaustive exercise.

NASA Technical Reports Server (NTRS)

Coester, N.; Elliott, J. C.; Luft, U. C.

1973-01-01

Ten men worked on a bicycle ergometer at increasing work loads to exhaustion in 15 min. Each performed one test breathing air and another with added CO2 in random sequence. ECG was recorded during exercise and for 30 min of recovery. Arterial samples for blood gases, pH, and electrolytes were drawn at rest, in the last minute of exercise and at 1, 4, 10, 20, and 30 min thereafter. A striking increase in the amplitude of T and P waves was observed reaching a maximum in the first 2 min after exercise. All electrolytes measured were increased at the end of exercise, most markedly potassium (60%) and phosphorus (53%). Potassium dropped faster than all others to below resting values in 4 min coinciding with the lowest levels in plasma bicarbonate. ECG alterations were not closely related in time with any single factor such as potassium, but appeared to reflect an interaction of the transient mineral and acid-base imbalance during and immediately following exhaustive exercise.

Evidence for hysteresis in the cerebral pressure-flow relationship in healthy men.

PubMed

Brassard, Patrice; Ferland-Dutil, Hélène; Smirl, Jonathan D; Paquette, Myriam; Le Blanc, Olivier; Malenfant, Simon; Ainslie, Philip N

2017-04-01

The cerebrovasculature is more efficient at compensating for pharmacologically induced transient hypertension versus transient hypotension. Whether this phenomenon exists during nonpharmacologically induced hypertension and hypotension is currently unknown. We compared the percent change in mean velocity in the middle cerebral artery (MCAvmean) per percent change in mean arterial pressure (MAP) (%ΔMCAVmean/%ΔMAP) during transient hypertension and hypotension induced during squat-stand maneuvers performed at 0.05 Hz (20-s cycles) and 0.10 Hz (10-s cycles) in 58 male volunteers. %ΔMCAvmean/%ΔMAP was attenuated by 25% ( P = 0.03, 0.05 Hz) and 47% ( P < 0.0001, 0.10 Hz) during transient hypertension versus hypotension. Thus, these findings indicate that the brain in healthy men is better adapted to compensate for physiologically relevant transient hypertension than hypotension. NEW & NOTEWORTHY The novel finding of this study is that the change in middle cerebral artery mean flow velocity is attenuated during hypertension compared with hypotension physiologically induced by oscillations in blood pressure in men. These results support that the human brain is more effective at compensating for transient hypertension than hypotension. Copyright © 2017 the American Physiological Society.

Exercise Alters Gut Microbiota Composition and Function in Lean and Obese Humans.

PubMed

Allen, Jacob M; Mailing, Lucy J; Niemiro, Grace M; Moore, Rachel; Cook, Marc D; White, Bryan A; Holscher, Hannah D; Woods, Jeffrey A

2018-04-01

Exercise is associated with altered gut microbial composition, but studies have not investigated whether the gut microbiota and associated metabolites are modulated by exercise training in humans. We explored the impact of 6 wk of endurance exercise on the composition, functional capacity, and metabolic output of the gut microbiota in lean and obese adults with multiple-day dietary controls before outcome variable collection. Thirty-two lean (n = 18 [9 female]) and obese (n = 14 [11 female]), previously sedentary subjects participated in 6 wk of supervised, endurance-based exercise training (3 d·wk) that progressed from 30 to 60 min·d and from moderate (60% of HR reserve) to vigorous intensity (75% HR reserve). Subsequently, participants returned to a sedentary lifestyle activity for a 6-wk washout period. Fecal samples were collected before and after 6 wk of exercise, as well as after the sedentary washout period, with 3-d dietary controls in place before each collection. β-diversity analysis revealed that exercise-induced alterations of the gut microbiota were dependent on obesity status. Exercise increased fecal concentrations of short-chain fatty acids in lean, but not obese, participants. Exercise-induced shifts in metabolic output of the microbiota paralleled changes in bacterial genes and taxa capable of short-chain fatty acid production. Lastly, exercise-induced changes in the microbiota were largely reversed once exercise training ceased. These findings suggest that exercise training induces compositional and functional changes in the human gut microbiota that are dependent on obesity status, independent of diet and contingent on the sustainment of exercise.

Prophylactic effects of swimming exercise on autophagy-induced muscle atrophy in diabetic rats

PubMed Central

Lee, Youngjeon; Kim, Joo-Heon; Hong, Yunkyung; Lee, Sang-Rae; Chang, Kyu-Tae

2012-01-01

Diabetes decreases skeletal muscle mass and induces atrophy. However, the mechanisms by which hyperglycemia and insulin deficiency modify muscle mass are not well defined. In this study, we evaluated the effects of swimming exercise on muscle mass and intracellular protein degradation in diabetic rats, and proposed that autophagy inhibition induced by swimming exercise serves as a hypercatabolic mechanism in the skeletal muscles of diabetic rats, supporting a notion that swimming exercise could efficiently reverse the reduced skeletal muscle mass caused by diabetes. Adult male Sprague-Dawley rats were injected intraperitoneally with streptozotocin (60 mg/kg body weight) to induce diabetes and then submitted to 1 hr per day of forced swimming exercise, 5 days per week for 4 weeks. We conducted an intraperitoneal glucose tolerance test on the animals and measured body weight, skeletal muscle mass, and protein degradation and examined the level of autophagy in the isolated extensor digitorum longus, plantaris, and soleus muscles. Body weight and muscle tissue mass were higher in the exercising diabetic rats than in control diabetic rats that remained sedentary. Compared to control rats, exercising diabetic rats had lower blood glucose levels, increased intracellular contractile protein expression, and decreased autophagic protein expression. We conclude that swimming exercise improves muscle mass in diabetes-induced skeletal muscle atrophy, suggesting the activation of autophagy in diabetes contributes to muscle atrophy through hypercatabolic metabolism and that aerobic exercise, by suppressing autophagy, may modify or reverse skeletal muscle wasting in diabetic patients. PMID:23091517

Low-Dose Pulsatile Interleukin-6 As a Treatment Option for Diabetic Peripheral Neuropathy.

PubMed

Cox, April Ann; Sagot, Yves; Hedou, Gael; Grek, Christina; Wilkes, Travis; Vinik, Aaron I; Ghatnekar, Gautam

2017-01-01

Diabetic peripheral neuropathy (DPN) remains one of the most common and serious complications of diabetes. Currently, pharmacological agents are limited to treating the pain associated with DPN, and do not address the underlying pathological mechanisms driving nerve damage, thus leaving a significant unmet medical need. Interestingly, research conducted using exercise as a treatment for DPN has revealed interleukin-6 (IL-6) signaling to be associated with many positive benefits such as enhanced blood flow and lipid metabolism, decreased chronic inflammation, and peripheral nerve fiber regeneration. IL-6, once known solely as a pro-inflammatory cytokine, is now understood to signal as a multifunctional cytokine, capable of eliciting both pro- and anti-inflammatory responses in a context-dependent fashion. IL-6 released from muscle in response to exercise signals as a myokine and as such has a unique kinetic profile, whereby levels are transiently elevated up to 100-fold and return to baseline levels within 4 h. Importantly, this kinetic profile is in stark contrast to long-term IL-6 elevation that is associated with pro-inflammatory states. Given exercise induces IL-6 myokine signaling, and exercise has been shown to elicit numerous beneficial effects for the treatment of DPN, a causal link has been suggested. Here, we discuss both the clinical and preclinical literature related to the application of IL-6 as a treatment strategy for DPN. In addition, we discuss how IL-6 may directly modulate Schwann and nerve cells to explore a mechanistic understanding of how this treatment elicits a neuroprotective and/or regenerative response. Collectively, studies suggest that IL-6, when administered in a low-dose pulsatile strategy to mimic the body's natural response to exercise, may prove to be an effective treatment for the protection and/or restoration of peripheral nerve function in DPN. This review highlights the studies supporting this assertion and provides rationale for continued investigation of IL-6 for the treatment of DPN.

The Impact of Mild Heat Stress During Prolonged Running On Gastrointestinal Integrity, Gastrointestinal Symptoms, Systemic Endotoxin and Cytokine Profiles.

PubMed

Snipe, Rhiannon M J; Khoo, Anthony; Kitic, Cecilia M; Gibson, Peter R; Costa, Ricardo J S

2018-02-07

The study aimed to determine the effects of mild exertional heat stress on intestinal injury, permeability, gastrointestinal symptoms, and systemic endotoxin and cytokine responses. Ten endurance runners completed 2 h of running at 60% V̇O 2max in warm (WARM: 30°C) and temperate (TEMP: 22°C) ambient conditions. Rectal temperature (T re ) and gastrointestinal symptoms were recorded every 10 min during exercise. Blood samples were collected pre- and post-exercise, and during recovery to determine plasma intestinal fatty acid-binding protein (I-FABP) and cortisol concentrations, and systemic endotoxin and inflammatory cytokine profiles. Urinary lactulose:L-rhamnose ratio (L/R) was used to measure small intestine permeability. Compared with TEMP, WARM significantly increased T re from 50 min onwards (38.1±0.3°C vs. 38.4±0.5°C, respectively; p<0.01), gastrointestinal symptoms (p=0.017), post-exercise plasma cortisol (26% vs. 59%, respectively; p<0.001) and I-FABP (127% vs. 184%, respectively; p<0.001) concentrations. Circulatory anti-endotoxin antibodies increased post-exercise (p<0.001) on WARM (20%) and TEMP (28%). No differences were observed for plasma endotoxin concentration (6% vs. 5% increase, respectively) or small intestine permeability (L/R 0.026±0.010 and 0.025±0.015, respectively). Both pro- and anti-inflammatory cytokines increased post-exercise, with inflammatory response cytokines TNF-α (p=0.015) and IL-8 (p=0.044), and compensatory anti-inflammatory cytokines IL-10 (p=0.065), and IL-1ra higher on WARM than TEMP. Findings suggest that exposure to warm ambient conditions during prolonged submaximal running induces transient intestinal epithelial injury, increases gastrointestinal symptoms, and promotes greater perturbations to the systemic cytokine profile compared to running in temperate conditions. © Georg Thieme Verlag KG Stuttgart · New York.

Use of Biomarkers to Optimize Heat Acclimation in Women

DTIC Science & Technology

1996-10-01

that synthesis of HSP72 was induced in lymphocytes, spleen cells and soleus muscle after 20 min of exercise while rectal temperature elevated above 40...lethal temperatures for death due to nonexertionally and exertionally induced heat exhaustion, respectively (15). Upon completion of the exercise ...During exercise , interstitial fluid levels are reduced due to sweat formation and fluid shifts which tend to induce hypovolemia, compromising

Exercise Protects against PCB-Induced Inflammation and Associated Cardiovascular Risk Factors

PubMed Central

Murphy, Margaret O.; Petriello, Michael C.; Han, Sung Gu; Sunkara, Manjula; Morris, Andrew J; Esser, Karyn; Hennig, Bernhard

2015-01-01

Polychlorinated biphenyls (PCBs) are persistent environmental pollutants that contribute to the initiation of cardiovascular disease. Exercise has been shown to reduce the risk of cardiovascular disease; however, whether exercise can modulate PCB-induced vascular endothelial dysfunction and associated cardiovascular risk factors is unknown. We examined the effects of exercise on coplanar PCB- induced cardiovascular risk factors including oxidative stress, inflammation, impaired glucose tolerance, hypercholesteremia, and endothelium-dependent relaxation. Male ApoE−/− mice were divided into sedentary and exercise groups (voluntary wheel running) over a 12 week period. Half of each group was exposed to vehicle or PCB 77 at weeks 1, 2, 9, and 10. For ex vivo studies, male C57BL/6 mice exercised via voluntary wheel training for 5 weeks and then were administered with vehicle or PCB 77 24 hours before vascular reactivity studies were performed. Exposure to coplanar PCB increased risk factors associated with cardiovascular disease, including oxidative stress and systemic inflammation, glucose intolerance, and hypercholesteremia. The 12 week exercise intervention significantly reduced these pro-atherogenic parameters. Exercise also upregulated antioxidant enzymes including phase II detoxification enzymes. Sedentary animals exposed to PCB 77 exhibited endothelial dysfunction as demonstrated by significant impairment of endothelium-dependent relaxation, which was prevented by exercise. Lifestyle modifications such as aerobic exercise could be utilized as a therapeutic approach for the prevention of adverse cardiovascular health effects induced by environmental pollutants such as PCBs. Keywords: exercise, polychlorinated biphenyl, endothelial function, antioxidant response, cardiovascular disease, inflammation, oxidative stress PMID:25586614

Aerobic exercise interventions reduce blood pressure in patients after stroke or transient ischaemic attack: a systematic review and meta-analysis.

PubMed

Wang, Cheng; Redgrave, Jessica; Shafizadeh, Mohsen; Majid, Arshad; Kilner, Karen; Ali, Ali N

2018-05-09

Secondary vascular risk reduction is critical to preventing recurrent stroke. We aimed to evaluate the effect of exercise interventions on vascular risk factors and recurrent ischaemic events after stroke or transient ischaemic attack (TIA). Intervention systematic review and meta-analysis. OVID MEDLINE, PubMed, The Cochrane Library, Web of Science, The National Institute for Health and Care Excellence, TRIP Database, CINAHL, PsycINFO, SCOPUS, UK Clinical Trials Gateway and the China National Knowledge Infrastructure were searched from 1966 to October 2017. Randomised controlled trials evaluating aerobic or resistance exercise interventions on vascular risk factors and recurrent ischaemic events among patients with stroke or TIA, compared with control. Twenty studies (n=1031) were included. Exercise interventions resulted in significant reductions in systolic blood pressure (SBP) -4.30 mm Hg (95% CI -6.77 to -1.83) and diastolic blood pressure -2.58 mm Hg (95% CI -4.7 to -0.46) compared with control. Reduction in SBP was most pronounced among studies initiating exercise within 6 months of stroke or TIA (-8.46 mm Hg, 95% CI -12.18 to -4.75 vs -2.33 mm Hg, 95% CI -3.94 to -0.72), and in those incorporating an educational component (-7.81 mm Hg, 95% CI -14.34 to -1.28 vs -2.78 mm Hg, 95% CI -4.33 to -1.23). Exercise was also associated with reductions in total cholesterol (-0.27 mmol/L, 95% CI -0.54 to 0.00), but not fasting glucose or body mass index. One trial reported reductions in secondary vascular events with exercise, but was insufficiently powered. Exercise interventions can result in clinically meaningful blood pressure reductions, particularly if initiated early and alongside education. © 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.

Effect of Permissive Dehydration on Induction and Decay of Heat Acclimation, and Temperate Exercise Performance

PubMed Central

Neal, Rebecca A.; Massey, Heather C.; Tipton, Michael J.; Young, John S.; Corbett, Jo

2016-01-01

Purpose: It has been suggested that dehydration is an independent stimulus for heat acclimation (HA), possibly through influencing fluid-regulation mechanisms and increasing plasma volume (PV) expansion. There is also some evidence that HA may be ergogenic in temperate conditions and that this may be linked to PV expansion. We investigated: (i) the influence of dehydration on the time-course of acquisition and decay of HA; (ii) whether dehydration augmented any ergogenic benefits in temperate conditions, particularly those related to PV expansion. Methods: Eight males [VO2max: 56.9(7.2) mL·kg−1·min−1] undertook two HA programmes (balanced cross-over design), once drinking to maintain euhydration (HAEu) and once with restricted fluid-intake (HADe). Days 1, 6, 11, and 18 were 60 min exercise-heat stress tests [HST (40°C; 50% RH)], days 2–5 and 7–10 were 90 min, isothermal-strain (Tre ~ 38.5°C), exercise-heat sessions. Performance parameters [VO2max, lactate threshold, efficiency, peak power output (PPO)] were determined pre and post HA by graded exercise test (22°C; 55%RH). Results: During isothermal-strain sessions hypohydration was achieved in HADe and euhydration maintained in HAEu [average body mass loss −2.71(0.82)% vs. −0.56(0.73)%, P < 0.001], but aldosterone concentration, power output, and cardiovascular strain were unaffected by dehydration. HA was evident on day 6 {reduced end-exercise Tre [−0.30(0.27)°C] and exercise heart rate [−12(15) beats.min−1], increased PV [+7.2(6.4)%] and sweat-loss [+0.25(0.22) L.h−1], P < 0.05} with some further adaptations on day 11 {further reduced end-exercise Tre [−0.25(0.19)°C] and exercise heart rate [−3(9) beats.min−1], P < 0.05}. These adaptations were not notably affected by dehydration and were generally maintained 7-days post HA. Performance parameters were unchanged, apart from increased PPO (+16(20) W, irrespective of condition). Conclusions: When thermal-strain is matched, permissive dehydration which induces a mild, transient, hypohydration does not affect the acquisition and decay of HA, or endurance performance parameters. Irrespective of hydration, trained individuals require >5 days to optimize HA. PMID:27932993

Changes in circulating angiogenic factors after an acute training bout before and after resistance training with or without whole-body-vibration training

NASA Astrophysics Data System (ADS)

Beijer, Åsa; Degens, Hans; May, Francisca; Bloch, Wilhelm; Rittweger, Joern; Rosenberger, Andre

2012-07-01

Both Resistance Exercise and Whole-Body-Vibration training are currently considered as countermeasures against microgravity-induced physiological deconditioning. Here we investigated the effects of whole-body vibration superimposed upon resistance exercise. Within this context, the present study focuses on changes in circulating angiogenic factors as indicators of skeletal muscle adaption. Methods: Twenty-six healthy male subjects (25.2 ± 4.2 yr) were included in this two-group parallel-designed study and randomly assigned to one of the training interventions: either resistance exercise (RE) or resistance vibration exercise (RVE). Participants trained 2-3 times per week for 6 weeks (completing 16 training sessions), where one session took 9 ± 1 min. Participants trained with weights on a guided barbell. The individual training load was set at 80% of their 1-Repetition-Maximum. Each training session consisted of three sets with 8 squats and 12 heel raises, following an incremental training design with regards to weight (RE and RVE) and vibration frequency (RVE only). The vibration frequency was increased from 20 Hz in the first week till 40 Hz during the last two weeks with 5-Hz weekly increments. At the first and 16 ^{th} training session, six blood samples (pre training and 2 min, 5 min, 15 min, 35 min and 75 min post training) were taken. Circulating levels of vascular endothelial growth factor (VEGF), Endostatin and Matrix Metalloproteinases -2 and -9 (MMPs) were determined in serum using Enzyme-linked Immunosorbent Assays. Results: MMP-2 levels increased by 7.0% (SE = 2.7%, P < 0.001) within two minutes after the exercise bout and then decreased to 5.7% below baseline (SE = 2.4%, P < 0.001) between 15 and 75 minutes post exercise. This response was comparable before and after the training programs (P = 0.70) and also between the two intervention groups (P = 0.42). Preliminary analyses indicate that a similar pattern applies to circulating MMP-9, VEGF and Endostatin levels. Conclusion: The present findings suggest 1) that resistance exercise, both with and without superimposed vibration, leads to a transient rise in circulating angiogenic factors, 2) which is not altered after a period of resistance exercise with or without vibration.

Time-Dependent Effects of Acute Exercise on University Students’ Cognitive Performance in Temperate and Cold Environments

PubMed Central

Ji, Ling-Yu; Li, Xiao-Ling; Liu, Yang; Sun, Xiu-Wen; Wang, Hui-Fen; Chen, Long; Gao, Liang

2017-01-01

Background: Few studies have examined the acute exercise-induced changes in cognitive performance in different thermal environments and the time course effects. Objective: Investigate the time-dependent effects of acute exercise on university students’ processing speed, working memory and cognitive flexibility in temperate and cold environments. Method: Twenty male university students (age 23.5 ± 2.0 years) with moderate physical activity level participated in a repeated-measures within-subjects design. Processing speed, working memory and cognitive flexibility were assessed using CogState test battery at baseline (BASE), followed by a 45-min rest (REST), immediately after (EX) and 30 min after (POST-EX) 30-min moderate-intensity treadmill running in both temperate (TEMP; 25°C) and cold (COLD; 10°C) environments. Mean skin temperature (MST) and thermal sensation (TS) were also recorded. Two-way repeated measures ANOVA was performed to analyze each variable. Spearman’s rho was used to identify the correlations between MST, TS and cognitive performance. Results: Reaction time (RT) of processing speed and working memory decreased immediately after exercise in both conditions (processing speed: p = 0.003; working memory: p = 0.007). The facilitating effects on processing speed disappeared within 30 min after exercise in TEMP (p = 0.163) and COLD (p = 0.667), while improvements on working memory remained 30 min after exercise in TEMP (p = 0.047), but not in COLD (p = 0.663). Though RT of cognitive flexibility reduced in both conditions (p = 0.003), no significance was found between EX and REST (p = 0.135). Increased MST and TS were significantly associated with reductions in processing speed RT (MST: r = -0.341, p < 0.001; TS: r = -0.262, p = 0.001) and working memory RT (MST: r = -0.282, p < 0.001; TS: r = -0.2229, p = 0.005), and improvements in working memory accuracy (MST: r = 0.249, p = 0.002; TS: r = 0.255, p = 0.001). Conclusion: The results demonstrate different time-dependent effects of acute exercise on cognition in TEMP and COLD. Our study reveals facilitating effects of exercise on university students’ processing speed and working memory in both environments. However, in contrast to TEMP, effects on working memory in COLD are transient. PMID:28747896

Exercise-induced muscle damage and running economy in humans.

PubMed

Assumpção, Cláudio de Oliveira; Lima, Leonardo Coelho Rabello; Oliveira, Felipe Bruno Dias; Greco, Camila Coelho; Denadai, Benedito Sérgio

2013-01-01

Running economy (RE), defined as the energy demand for a given velocity of submaximal running, has been identified as a critical factor of overall distance running performance. Plyometric and resistance trainings, performed during a relatively short period of time (~15-30 days), have been successfully used to improve RE in trained athletes. However, these exercise types, particularly when they are unaccustomed activities for the individuals, may cause delayed onset muscle soreness, swelling, and reduced muscle strength. Some studies have demonstrated that exercise-induced muscle damage has a negative impact on endurance running performance. Specifically, the muscular damage induced by an acute bout of downhill running has been shown to reduce RE during subsequent moderate and high-intensity exercise (>65% VO₂max). However, strength exercise (i.e., jumps, isoinertial and isokinetic eccentric exercises) seems to impair RE only for subsequent high-intensity exercise (~90% VO₂max). Finally, a single session of resistance exercise or downhill running (i.e., repeated bout effect) attenuates changes in indirect markers of muscle damage and blunts changes in RE.

Treadmill exercise alleviates depressive symptoms in rotenone-induced Parkinson disease rats

PubMed Central

Shin, Mal-Soon; Kim, Tae-Woon; Lee, Jae-Min; Sung, Yun-Hee; Lim, Baek-Vin

2017-01-01

Parkinson disease (PD) is characterized by selective loss of the dopaminergic neurons. The symptoms of depression following PD are closely associated with reduced activity of the serotonergic system in the dorsal raphe. We explored the antidepressive effect of exercise and its possible mechanism using the rotenone-induced PD rats. PD rats were induced by subcutaneously injection with rotenone for 14 days. The rats in the exercise groups were made to run on a treadmill for 30 min once a day during 14 consecutive days. Forced swimming test, immunohistochemistry for serotonin (5-hydroxytryptamine, 5-HT), tryptophan hydroxylase (TPH), and western blot for serotonin 1A (5-HT1A) receptor were conducted. Injection of rotenone induced PD rats. PD rats showed depressive state and treadmill exercise ameliorated this depressive state. 5-HT, TPH, and 5-HT1A receptor expressions in the dorsal raphe were suppressed by rotenone injection and treadmill exercise increased the expressions of 5-HT, TPH, and 5-HT1A receptor in the rotenone-injected rats. The present results show that treadmill exercise ameliorated depressive symptoms in the rotenone-induced PD rats. The antidepressive effect of treadmill exercise might be ascribed to the enhancement of serotonergic function through upregulation of 5-HT1A expression in the dorsal raphe. PMID:28503522

Treadmill exercise alleviates depressive symptoms in rotenone-induced Parkinson disease rats.

PubMed

Shin, Mal-Soon; Kim, Tae-Woon; Lee, Jae-Min; Sung, Yun-Hee; Lim, Baek-Vin

2017-04-01

Parkinson disease (PD) is characterized by selective loss of the dopaminergic neurons. The symptoms of depression following PD are closely associated with reduced activity of the serotonergic system in the dorsal raphe. We explored the antidepressive effect of exercise and its possible mechanism using the rotenone-induced PD rats. PD rats were induced by subcutaneously injection with rotenone for 14 days. The rats in the exercise groups were made to run on a treadmill for 30 min once a day during 14 consecutive days. Forced swimming test, immunohistochemistry for serotonin (5-hydroxytryptamine, 5-HT), tryptophan hydroxylase (TPH), and western blot for serotonin 1A (5-HT1A) receptor were conducted. Injection of rotenone induced PD rats. PD rats showed depressive state and treadmill exercise ameliorated this depressive state. 5-HT, TPH, and 5-HT1A receptor expressions in the dorsal raphe were suppressed by rotenone injection and treadmill exercise increased the expressions of 5-HT, TPH, and 5-HT1A receptor in the rotenone-injected rats. The present results show that treadmill exercise ameliorated depressive symptoms in the rotenone-induced PD rats. The antidepressive effect of treadmill exercise might be ascribed to the enhancement of serotonergic function through upregulation of 5-HT1A expression in the dorsal raphe.

Exercise-Induced Hypertrophic and Oxidative Signaling Pathways and Myokine Expression in Fast Muscle of Adult Zebrafish

PubMed Central

Rovira, Mireia; Arrey, Gerard; Planas, Josep V.

2017-01-01

Skeletal muscle is a plastic tissue that undergoes cellular and metabolic adaptations under conditions of increased contractile activity such as exercise. Using adult zebrafish as an exercise model, we previously demonstrated that swimming training stimulates hypertrophy and vascularization of fast muscle fibers, consistent with the known muscle growth-promoting effects of exercise and with the resulting increased aerobic capacity of this tissue. Here we investigated the potential involvement of factors and signaling mechanisms that could be responsible for exercise-induced fast muscle remodeling in adult zebrafish. By subjecting zebrafish to swimming-induced exercise, we observed an increase in the activity of mammalian target of rapamycin (mTOR) and Mef2 protein levels in fast muscle. We also observed an increase in the protein levels of the mitotic marker phosphorylated histone H3 that correlated with an increase in the protein expression levels of Pax7, a satellite-like cell marker. Furthermore, the activity of AMP-activated protein kinase (AMPK) was also increased by exercise, in parallel with an increase in the mRNA expression levels of pgc1α and also of pparda, a β-oxidation marker. Changes in the mRNA expression levels of slow and fast myosin markers further supported the notion of an exercise-induced aerobic phenotype in zebrafish fast muscle. The mRNA expression levels of il6, il6r, apln, aplnra and aplnrb, sparc, decorin and igf1, myokines known in mammals to be produced in response to exercise and to signal through mTOR/AMPK pathways, among others, were increased in fast muscle of exercised zebrafish. These results support the notion that exercise increases skeletal muscle growth and myogenesis in adult zebrafish through the coordinated activation of the mTOR-MEF2 and AMPK-PGC1α signaling pathways. These results, coupled with altered expression of markers for oxidative metabolism and fast-to-slow fiber-type switch, also suggest improved aerobic capacity as a result of swimming-induced exercise. Finally, the induction of myokine expression by swimming-induced exercise support the hypothesis that these myokines may have been produced and secreted by the exercised zebrafish muscle and acted on fast muscle cells to promote metabolic remodeling. These results support the use of zebrafish as a suitable model for studies on muscle remodeling in vertebrates, including humans. PMID:29326600

Ultrafast transient grating radiation to optical image converter

DOEpatents

Stewart, Richard E; Vernon, Stephen P; Steel, Paul T; Lowry, Mark E

2014-11-04

A high sensitivity transient grating ultrafast radiation to optical image converter is based on a fixed transmission grating adjacent to a semiconductor substrate. X-rays or optical radiation passing through the fixed transmission grating is thereby modulated and produces a small periodic variation of refractive index or transient grating in the semiconductor through carrier induced refractive index shifts. An optical or infrared probe beam tuned just below the semiconductor band gap is reflected off a high reflectivity mirror on the semiconductor so that it double passes therethrough and interacts with the radiation induced phase grating therein. A small portion of the optical beam is diffracted out of the probe beam by the radiation induced transient grating to become the converted signal that is imaged onto a detector.

Effect of resistance exercise under conditions of reduced blood insulin on AMPKα Ser485/491 inhibitory phosphorylation and AMPK pathway activation.

PubMed

Kido, Kohei; Yokokawa, Takumi; Ato, Satoru; Sato, Koji; Fujita, Satoshi

2017-08-01

Insulin stimulates skeletal muscle glucose uptake via activation of the protein kinase B/Akt (Akt) pathway. Recent studies suggest that insulin downregulates AMP-activated protein kinase (AMPK) activity via Ser485/491 phosphorylation of the AMPK α-subunit. Thus lower blood insulin concentrations may induce AMPK signal activation. Acute exercise is one method to stimulate AMPK activation; however, no study has examined the relationship between blood insulin levels and acute resistance exercise-induced AMPK pathway activation. Based on previous findings, we hypothesized that the acute resistance exercise-induced AMPK pathway activation would be augmented by disruptions in insulin secretion through a decrease in AMPKα Ser485/491 inhibitory phosphorylation. To test the hypothesis, 10-wk-old male Sprague-Dawley rats were administered the toxin streptozotocin (STZ; 55 mg/kg) to destroy the insulin secreting β-cells. Three days postinjection, the right gastrocnemius muscle from STZ and control rats was subjected to resistance exercise by percutaneous electrical stimulation. Animals were killed 0, 1, or 3 h later; activation of the Akt/AMPK and downstream pathways in the muscle tissue was analyzed by Western blotting and real-time PCR. Notably, STZ rats showed a significant decrease in basal Akt and AMPKα Ser485/491 phosphorylation, but substantial exercise-induced increases in both AMPKα Thr172 and acetyl-CoA carboxylase (ACC) Ser79 phosphorylation were observed. Although no significant impact on resistance exercise-induced Akt pathway activation or glucose uptake was found, resistance exercise-induced peroxisome proliferator-activated receptor (PPAR)-γ coactivator-1 α (PGC-1α) gene expression was augmented by STZ treatment. Collectively, these data suggest that circulating insulin levels may regulate acute resistance exercise-induced AMPK pathway activation and AMPK-dependent gene expression relating to basal AMPKα Ser485/491 phosphorylation. Copyright © 2017 the American Physiological Society.

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

Cell-derived microparticles promote coagulation after moderate exercise.

PubMed

Sossdorf, Maik; Otto, Gordon P; Claus, Ralf A; Gabriel, Holger H W; Lösche, Wolfgang

2011-07-01

Cell-derived procoagulant microparticles (MP) might be able to contribute to exercise-induced changes in blood hemostasis. This study aimed to examine (i) the concentration and procoagulant activity of cell-derived MP after a moderate endurance exercise and (ii) the differences in the release, clearance, and activity of MP before and after exercise between trained and untrained individuals. All subjects performed a single bout of physical exercise on a bicycle ergometer for 90 min at 80% of their individual anaerobic threshold. MP were identified and quantified by flow cytometry measurements. Procoagulant activity of MP was measured by a prothrombinase activity assay as well as tissue factor-induced fibrin formation in MP-containing plasma. At baseline, no differences were observed for the absolute number and procoagulant activities of MP between trained and untrained subjects. However, trained individuals had a lower number of tissue factor-positive monocyte-derived MP compared with untrained individuals. In trained subjects, exercise induced a significant increase in the number of MP derived from platelets, monocytes, and endothelial cells, with maximum values at 45 min after exercise and returned to basal levels at 2 h after exercise. Untrained subjects revealed a similar increase in platelet-derived MP, but their level was still increased at 2 h after exercise, indicating a reduced clearance compared with trained individuals. Procoagulant activities of MP were increased immediately after exercise and remained elevated up to 2 h after exercise. We conclude that increased levels of MP were found in healthy individuals after an acute bout of exercise, that the amount of circulating MP contributes to an exercise-induced increase of hemostatic potential, and that there were differences in kinetic and dynamic characteristics between trained and untrained individuals.

The ameliorative effects of exercise on cognitive impairment and white matter injury from blood-brain barrier disruption induced by chronic cerebral hypoperfusion in adolescent rats.

PubMed

Lee, Jae-Min; Park, Jong-Min; Song, Min Kyung; Oh, Yoo Joung; Kim, Chang-Ju; Kim, Youn-Jung

2017-01-18

Vascular dementia is the progressive change in blood vessels that leads to neuronal injuries in vulnerable areas induced by chronic cerebral hypoperfusion (CCH). CCH induces disruption of blood-brain barrier (BBB), and this BBB disruption can initiate the cognitive impairment and white matter injury. In the present study, we evaluated the effect of treadmill exercise on the cognitive impairment, white matter injury, and BBB disruption induced by CCH. Vascular dementia was induced by permanent bilateral common carotid arteries occlusion (BCCAO) in rats. The rats in the exercise group were made to run on a treadmill for 30min once a day for 14 weeks, starting 4 weeks after birth. Our results revealed that treadmill exercise group was alleviated the cognitive impairment and myelin degradation induced by CCH. The disruption of BBB after CCH indicates degradation of occludin, zonula occluden-1 (ZO-1), and up-regulation of matrix metalloproteinases (MMPs). Treadmill exercise may provide protective effects on BBB disruption from degradation of occludin, ZO-1, and overexpression of MMP-9 after CCH. These findings suggest that treadmill exercise ameliorates cognitive impairment and white matter injury from BBB disruption induced by CCH in rats. The present study will be valuable for means of prophylactic and therapeutic intervention for patients with CCH. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Prior exercise and standing as strategies to circumvent sitting-induced leg endothelial dysfunction.

PubMed

Morishima, Takuma; Restaino, Robert M; Walsh, Lauren K; Kanaley, Jill A; Padilla, Jaume

2017-06-01

We have previously shown that local heating or leg fidgeting can prevent prolonged sitting-induced leg endothelial dysfunction. However, whether physical activity prevents subsequent sitting-induced leg endothelial dysfunction remains unknown. Herein, we tested the hypothesis that sitting-induced leg endothelial dysfunction would be prevented by prior exercise. We also examined if, in the absence of exercise, standing is an effective alternative strategy to sitting for conserving leg endothelial function. Fifteen young healthy subjects completed three randomized experimental trials: (1) sitting without prior exercise; (2) sitting with prior exercise; and (3) standing without prior exercise. Following baseline popliteal artery flow-mediated dilation (FMD) measurements, subjects maintained a supine position for 45 min in the sitting and standing trials, without prior exercise, or performed 45 min of leg cycling before sitting (i.e. sitting with prior exercise trial). Thereafter, subjects were positioned into a seated or standing position, according to the trial, for 3 h. Popliteal artery FMD measures were then repeated. Three hours of sitting without prior exercise caused a significant impairment in popliteal artery FMD (baseline: 3.8±0.5%, post-sitting: 1.5±0.5%, P <0.05), which was prevented when sitting was preceded by a bout of cycling exercise (baseline: 3.8±0.5%, post-sitting: 3.6±0.7%, P >0.05). Three hours of standing did not significantly alter popliteal artery FMD (baseline: 4.1±0.4%, post-standing: 4.3±0.4%, P >0.05). In conclusion, prolonged sitting-induced leg endothelial dysfunction can be prevented by prior aerobic exercise. In addition, in the absence of exercise, standing represents an effective substitute to sitting for preserving leg conduit artery endothelial function. © 2017 The Author(s). published by Portland Press Limited on behalf of the Biochemical Society.

Prevalence and prognostic value of exercise-induced ventricular arrhythmias.

PubMed

Partington, Sara; Myers, Jonathan; Cho, Shaun; Froelicher, Victor; Chun, Sung

2003-01-01

The purpose of this study was to determine the prevalence and prognostic significance of exercise-induced ventricular arrhythmias (EIVAs) in patients referred for exercise testing, considering the arrhythmic substrate and exercise-induced ischemia. EIVAs are frequently observed during exercise testing, but their prognostic significance is uncertain. The design of this study was a retrospective analysis of prospectively collected data, and it took place in 2 university-affiliated Veterans Affairs Medical Centers. Patients comprised 6213 consecutive males referred for exercise tests. We measured clinical exercise test responses and all-cause mortality after a mean follow-up of 6 +/- 4 years. EIVAs were defined as frequent premature ventricular contractions (PVCs) constituting >10% of all ventricular depolarizations during any 30 second electrocardiogram recording, or a run of > or =3 consecutive PVCs during exercise or recovery. A total of 1256 patients (20%) died during follow-up. EIVAs occurred in 503 patients (8%); the prevalence of EIVAs increased in older patients and in those with cardiopulmonary disease, resting PVCs, and ischemia during exercise. EIVAs were associated with mortality irrespective of the presence of cardiopulmonary disease or exercise-induced ischemia. In those without cardiopulmonary disease, mortality differed more so later in follow up than earlier. In those without resting PVCs, EIVAs were also predictive of mortality, but in those with resting PVCs, poorer prognosis was not worsened by the presence of EIVAs. Exercise induced ischemia does not affect the prognostic value of EIVAs, whereas the arrhythmic substrate does. EIVAs and resting PVCs are both independent predictors of mortality after consideration of other clinical and exercise-test variables. These findings are of limited clinical significance because of the modest change in risk and the lack of any established intervention. However, they explain some of the previous controversy and highlight the need to consider resting PVCs and follow-up duration in assessing the clinical implications of EIVAs.

Treadmill Exercise Exerts Neuroprotection and Regulates Microglial Polarization and Oxidative Stress in a Streptozotocin-Induced Rat Model of Sporadic Alzheimer’s Disease

PubMed Central

Lu, Yujiao; Dong, Yan; Tucker, Donovan; Wang, Ruimin; Ahmed, Mohammad Ejaz; Brann, Darrell; Zhang, Quanguang

2017-01-01

Recent work has suggested that exercise may be beneficial in preventing or ameliorating symptoms of several neurological disorders, although the mechanism is not entirely understood. The current study was designed to examine the potential beneficial effect of treadmill exercise upon cognitive function in a streptozotocin (STZ)-induced rat model of Alzheimer’s disease (AD). Animals underwent treadmill exercise (30 min/day, 5 days/week) for 4 weeks after bilateral STZ intracerebroventricular injection (2.4 mg/kg). We demonstrated that treadmill exercise significantly attenuated STZ-induced neurodegeneration in the rat hippocampal CA1 region and strongly preserved hippocampal-dependent cognitive functioning. Further mechanistic investigation displayed a marked suppression of STZ-induced amyloid-β accumulation and tau phosphorylation. Intriguingly, treadmill exercise remarkably inhibited reactive gliosis following STZ insult and effectively shifted activated microglia from a pro-inflammatory M1 to an anti-inflammatory M2 phenotype, which was correlated with a significantly reduced expression of pro-inflammatory mediators and a corresponding enhancement of anti-inflammatory cytokine expression in the hippocampus. Furthermore, treadmill exercise caused a robust suppression of oxidative damage as evidenced by significantly reduced peroxynitrite production, lipid peroxidation, and oxidized DNA damage. Finally, treadmill exercise strongly attenuated STZ-induced mitochondrial dysfunction manifested by a dramatically elevated intra-mitochondrial cytochrome c oxidase activity and ATP synthesis, and markedly inhibited neuronal apoptosis in the hippocampus. These findings demonstrate that treadmill exercise has a multifactorial effect to attenuate many of the pathological processes that play a key role in AD, and provide further support for the beneficial role of exercise as a potential therapeutic option in AD treatment. PMID:28157094

Treadmill Exercise Exerts Neuroprotection and Regulates Microglial Polarization and Oxidative Stress in a Streptozotocin-Induced Rat Model of Sporadic Alzheimer's Disease.

PubMed

Lu, Yujiao; Dong, Yan; Tucker, Donovan; Wang, Ruimin; Ahmed, Mohammad Ejaz; Brann, Darrell; Zhang, Quanguang

2017-01-01

Recent work has suggested that exercise may be beneficial in preventing or ameliorating symptoms of several neurological disorders, although the mechanism is not entirely understood. The current study was designed to examine the potential beneficial effect of treadmill exercise upon cognitive function in a streptozotocin (STZ)-induced rat model of Alzheimer's disease (AD). Animals underwent treadmill exercise (30 min/day, 5 days/week) for 4 weeks after bilateral STZ intracerebroventricular injection (2.4 mg/kg). We demonstrated that treadmill exercise significantly attenuated STZ-induced neurodegeneration in the rat hippocampal CA1 region and strongly preserved hippocampal-dependent cognitive functioning. Further mechanistic investigation displayed a marked suppression of STZ-induced amyloid-β accumulation and tau phosphorylation. Intriguingly, treadmill exercise remarkably inhibited reactive gliosis following STZ insult and effectively shifted activated microglia from a pro-inflammatory M1 to an anti-inflammatory M2 phenotype, which was correlated with a significantly reduced expression of pro-inflammatory mediators and a corresponding enhancement of anti-inflammatory cytokine expression in the hippocampus. Furthermore, treadmill exercise caused a robust suppression of oxidative damage as evidenced by significantly reduced peroxynitrite production, lipid peroxidation, and oxidized DNA damage. Finally, treadmill exercise strongly attenuated STZ-induced mitochondrial dysfunction manifested by a dramatically elevated intra-mitochondrial cytochrome c oxidase activity and ATP synthesis, and markedly inhibited neuronal apoptosis in the hippocampus. These findings demonstrate that treadmill exercise has a multifactorial effect to attenuate many of the pathological processes that play a key role in AD, and provide further support for the beneficial role of exercise as a potential therapeutic option in AD treatment.

Validity of Retrospective Reports of Eating Behavior from the Eating Disorder Examination

DTIC Science & Technology

1999-01-01

counts of self- induced vomiting. misuse of laxatives or diuretics, fasting, and excessive exercise . To date, only three semi-structured assessment...of weight control (self- induced vomiting, laxative misuse. diuretic misuse. and intense exercising ) are assessed. Some of the individual items are...gain, such as self- induced vomiting; misuse of laxatives, diuretics, enemas, or other medications; fasting; or excessive exercise . C. The binge eating

Prognostic value of myocardial perfusion SPECT versus exercise electrocardiography in patients with ST-segment depression on resting electrocardiography.

PubMed

De Lorenzo, Andrea; Hachamovitch, Rory; Kang, Xingping; Gransar, Heidi; Sciammarella, Maria G; Hayes, Sean W; Friedman, John D; Cohen, Ishac; Germano, Guido; Berman, Daniel S

2005-01-01

The value of exercise-induced ST-segment depression for the prognostic evaluation of patients with 1 mm of ST depression or greater on the resting electrocardiogram is controversial. Patients who underwent exercise myocardial perfusion single photon emission computed tomography (MPS) and had resting ST depression of 1 mm or greater with a nondiagnostic exercise electrocardiographic response (n = 1122) were followed up for 3.4 +/- 2.3 years. Those with paced rhythm, pre-excitation, left bundle branch block, or myocardial revascularization within the first 60 days after MPS were excluded. Additional exercise-induced ST-segment depression was considered significant if > or = 2 mm MPS was scored semiquantitatively by use of a 20-segment model of the left ventricle; the percentage of myocardium involved with stress defects (% myo) was derived by normalizing to the maximal possible score of 80. Hard events were defined as nonfatal myocardial infarction or cardiac death. A Cox analysis was used to determine independent predictors of hard events among clinical, exercise, and nuclear variables. Hard event rates increased as a function of % myo for either patients with exercise-induced ST depression (1.4%/y for normal MPS vs 4.1%/y for % myo >10%, P < .03) or those without it (0.7%/y for normal MPS vs 3.0%/y for % myo >10%, P = .0001). Age, diabetes mellitus, shortness of breath as the presenting symptom, and % myo were independent predictors of hard events. Exercise-induced ST depression was predictive of hard events only when it was 3 mm or greater. The presence and extent of perfusion defects, reflected in the % myo, had incremental prognostic value over clinical variables and also over all degrees of exercise-induced ST depression. Although MPS effectively risk-stratifies patients with resting ST depression of 1 mm or greater, the prognostic value of exercise-induced ST depression is limited in these patients, with a small added risk when severe (> or = 3 mm).

Stress-Induced Depression Is Alleviated by Aerobic Exercise Through Up-Regulation of 5-Hydroxytryptamine 1A Receptors in Rats.

PubMed

Kim, Tae Woon; Lim, Baek Vin; Baek, Dongjin; Ryu, Dong-Soo; Seo, Jin Hee

2015-03-01

Stress is associated with depression, which induces many psychiatric disorders. Serotonin, also known as 5-hydroxy-tryptamine (5-HT), acts as a biochemical messenger and regulator in the brain. It also mediates several important physiological functions. Depression is closely associated with an overactive bladder. In the present study, we investigated the effect of treadmill exercise on stress-induced depression while focusing on the expression of 5-HT 1A (5-H1A) receptors in the dorsal raphe. Stress was induced by applying a 0.2-mA electric foot shock to rats. Each set of electric foot shocks comprised a 6-second shock duration that was repeated 10 times with a 30-second interval. Three sets of electric foot shocks were applied each day for 7 days. For the confirmation of depressive state, a forced swimming test was performed. To visualize the expression of 5-HT and tryptophan hydroxylase (TPH), immunohistochemistry for 5-HT and TPH in the dorsal raphe was performed. Expression of 5-H1A receptors was determined by western blot analysis. A depressive state was induced by stress, and treadmill exercise alleviated the depression symptoms in the stress-induced rats. Expressions of 5-HT, TPH, and HT 1A in the dorsal raphe were reduced by the induction of stress. Treadmill exercise increased 5-HT, TPH, and HT 1A expressions in the stress-induced rats. Treadmill exercise enhanced 5-HT synthesis through the up-regulation of 5-HT1A receptors, and improved the stress-induced depression. In the present study, treadmill exercise improved depression symptoms by enhancing 5-HT1A receptor expression. The present results suggest that treadmill exercise might be helpful for the alleviation of overactive bladder and improve sexual function.

Effects of Exercise Intensity on Postexercise Endothelial Function and Oxidative Stress

PubMed Central

McClean, Conor; Harris, Ryan A.; Brown, Malcolm; Brown, John C.; Davison, Gareth W.

2015-01-01

Purpose. To measure endothelial function and oxidative stress immediately, 90 minutes, and three hours after exercise of varying intensities. Methods. Sixteen apparently healthy men completed three exercise bouts of treadmill running for 30 minutes at 55% V˙O2max (mild); 20 minutes at 75% V˙O2max (moderate); or 5 minutes at 100% V˙O2max (maximal) in random order. Brachial artery flow-mediated dilation (FMD) was assessed with venous blood samples drawn for measurement of endothelin-1 (ET-1), lipid hydroperoxides (LOOHs), and lipid soluble antioxidants. Results. LOOH increased immediately following moderate exercise (P < 0.05). ET-1 was higher immediately after exercise and 3 hours after exercise in the mild trial compared to maximal one (P < 0.05). Transient decreases were detected for ΔFMD/ShearAUC from baseline following maximal exercise, but it normalised at 3 hours after exercise (P < 0.05). Shear rate was higher immediately after exercise in the maximal trial compared to mild exercise (P < 0.05). No changes in baseline diameter, peak diameter, absolute change in diameter, or FMD were observed following any of the exercise trials (P > 0.05). Conclusions. Acute exercise at different intensities elicits varied effects on oxidative stress, shear rate, and ET-1 that do not appear to mediate changes in endothelial function measured by FMD. PMID:26583061

Effect of exercise on patient specific abdominal aortic aneurysm flow topology and mixing

PubMed Central

Arzani, Amirhossein; Les, Andrea S.; Dalman, Ronald L.; Shadden, Shawn C.

2014-01-01

SUMMARY Computational fluid dynamics modeling was used to investigate changes in blood transport topology between rest and exercise conditions in five patient-specific abdominal aortic aneurysm models. Magnetic resonance imaging was used to provide the vascular anatomy and necessary boundary conditions for simulating blood velocity and pressure fields inside each model. Finite-time Lyapunov exponent fields, and associated Lagrangian coherent structures, were computed from blood velocity data, and used to compare features of the transport topology between rest and exercise both mechanistically and qualitatively. A mix-norm and mix-variance measure based on fresh blood distribution throughout the aneurysm over time were implemented to quantitatively compare mixing between rest and exercise. Exercise conditions resulted in higher and more uniform mixing, and reduced the overall residence time in all aneurysms. Separated regions of recirculating flow were commonly observed in rest, and these regions were either reduced or removed by attached and unidirectional flow during exercise, or replaced with regional chaotic and transiently turbulent mixing, or persisted and even extended during exercise. The main factor that dictated the change in flow topology from rest to exercise was the behavior of the jet of blood penetrating into the aneurysm during systole. PMID:24493404

Microseism Induced by Transient Release of In Situ Stress During Deep Rock Mass Excavation by Blasting

NASA Astrophysics Data System (ADS)

Yang, Jianhua; Lu, Wenbo; Chen, Ming; Yan, Peng; Zhou, Chuangbing

2013-07-01

During deep rock mass excavation with the method of drill and blast, accompanying the secession of rock fragments and the formation of a new free surface, in situ stress on this boundary is suddenly released within several milliseconds, which is termed the transient release of in situ stress. In this process, enormous strain energy around the excavation face is instantly released in the form of kinetic energy and it inevitably induces microseismic events in surrounding rock masses. Thus, blasting excavation-induced microseismic vibrations in high-stress rock masses are attributed to the combined action of explosion and the transient release of in situ stress. The intensity of stress release-induced microseisms, which depends mainly on the magnitude of the in situ stress and the dimension of the excavation face, is comparable to that of explosion-induced vibrations. With the methods of time-energy density analysis, amplitude spectrum analysis, and finite impulse response (FIR) digital filter, microseismic vibrations induced by the transient release of in situ stress were identified and separated from recorded microseismic signals during a blast of deep rock masses in the Pubugou Hydropower Station. The results show that the low-frequency component in the microseismic records results mainly from the transient release of in situ stress, while the high-frequency component originates primarily from explosion. In addition, a numerical simulation was conducted to demonstrate the occurrence of microseismic events by the transient release of in situ stress, and the results seem to have confirmed fairly well the separated vibrations from microseismic records.

The preventive effect and duration of action of two doses of inhaled furosemide on exercise-induced asthma in children.

PubMed

Novembre, E; Frongia, G; Lombardi, E; Resti, M; Zammarchi, E; Vierucci, A

1995-12-01

Exercise-induced asthma can be prevented by treatment with inhaled furosemide. In this study we evaluated the effect and duration of action of two doses (15 and 30 mg) of inhaled furosemide in prevention of exercise-induced asthma in children. Ten children with exercise-induced asthma (8 boys and 2 girls, aged 6 to 13 years) were included in the study. Each patient was tested with three treatment regimens (placebo, 15 mg of furosemide, and 30 mg of furosemide) in random order on 3 separate days. Patients performed exercise challenges on a treadmill at 20 minutes and 1, 2, 3, and 6 hours after each treatment. Pulmonary function, urinary output, and fluid intake were monitored. Both doses of furosemide had a significantly greater protective effect than placebo, but there was no significant difference between the two doses of furosemide. The higher dose of furosemide was associated with increased urinary output and had a longer duration of action. A 30 mg dose of furosemide is more effective for treatment of exercise-induced asthma in terms of duration but has a significant diuretic effect.

Surgical treatment is effective in severe cases of exercise-induced laryngeal obstruction: A follow-up study.

PubMed

Norlander, Katarina; Johansson, Henrik; Jansson, Christer; Nordvall, Lennart; Nordang, Leif

2015-01-01

Surgery is an effective treatment in severe cases of supraglottic exercise-induced laryngeal obstruction (E-ILO). Conservatively treated subjects and subjects tested negative for E-ILO, who still experience breathing problems 1-3 years after diagnosis, tend to adjust their physical activity to a greater extent than surgically treated subjects. To investigate how symptoms and level of physical activity change over time in patients with E-ILO who have undergone surgery, patients with E-ILO treated conservatively and patients who tested negative for laryngeal obstruction at continuous laryngoscopy exercise-test (CLE-test). Patients referred for exercise-induced breathing difficulties answered questionnaires at diagnostic CLE-test and at follow-up. Questions regarded exercise-induced breathing problems, current physical activity level, and medical history of asthma and perennial allergy. Out of 84 invited subjects, 59 (70%) answered both questionnaires. Surgically treated subjects had less breathing problems at follow-up compared with conservatively treated subjects and subjects who tested negative (p < 0.001). None of the surgically treated subjects were less physically active or had changed sport due to exercise-induced dyspnoea, whereas 41.7% of the conservatively treated subjects had made such adjustments (p < 0.001).

Supplementation with beta-hydroxy-beta-methylbutyrate (HMB) and alpha-ketoisocaproic acid (KIC) reduces signs and symptoms of exercise-induced muscle damage in man.

PubMed

van Someren, Ken A; Edwards, Adam J; Howatson, Glyn

2005-08-01

This study examined the effects of beta-hydroxyl-beta-methylbutyrate (HMB) and alpha-ketoisocaproic acid (KIC) supplementation on signs and symptoms of exercise-induced muscle damage following a single bout of eccentrically biased resistance exercise. Six non-resistance trained male subjects performed an exercise protocol designed to induce muscle damage on two separate occasions, performed on the dominant or non-dominant arm in a counter-balanced crossover design. Subjects were assigned to an HMB/KIC (3 g HMB and 0.3 g alpha-ketoisocaproic acid, daily) or placebo treatment for 14 d prior to exercise in the counter-balanced crossover design. One repetition maximum (1RM), plasma creatine kinase activity (CK), delayed onset muscle soreness (DOMS), limb girth, and range of motion (ROM) were determined pre-exercise, at 1h, 24 h, 48 h, and 72 h post-exercise. DOMS and the percentage changes in 1RM, limb girth, and ROM all changed over the 72 h period (P < 0.05). HMB//IC supplementation attenuated the CK response, the percentage decrement in 1RM, and the percentage increase in limb girth (P < 0.05). In addition, DOMS was reduced at 24 h post-exercise (P < 0.05) in the HMB/KIC treatment. In conclusion, 14 d of HMB and KIC supplementation reduced signs and symptoms of exercise-induced muscle damage in non-resistance trained males following a single bout of eccentrically biased resistance exercise.

Circulating androgens in women: exercise-induced changes.

PubMed

Enea, Carina; Boisseau, Nathalie; Fargeas-Gluck, Marie Agnès; Diaz, Véronique; Dugué, Benoit

2011-01-01

Physical exercise is known to strongly stimulate the endocrine system in both sexes. Among these hormones, androgens (e.g. testosterone, androstenedione, dehydroepiandrosterone) play key roles in the reproductive system, muscle growth and the prevention of bone loss. In female athletes, excessive physical exercise may lead to disorders, including delay in the onset of puberty, amenorrhoea and premature osteoporosis. The free and total fractions of circulating androgens vary in response to acute and chronic exercise/training (depending on the type), but the physiological role of these changes is not completely understood. Although it is commonly accepted that only the free fraction of steroids has a biological action, this hypothesis has recently been challenged. Indeed, a change in the total fraction of androgen concentration may have a significant impact on cells (inducing genomic or non-genomic signalling). The purpose of this review, therefore, is to visit the exercise-induced changes in androgen concentrations and emphasize their potential effects on female physiology. Despite some discrepancies in the published studies (generally due to differences in the types and intensities of the exercises studied, in the hormonal status of the group of women investigated and in the methods for androgen determination), exercise is globally able to induce an increase in circulating androgens. This can be observed after both resistance and endurance acute exercises. For chronic exercise/training, the picture is definitely less clear and there are even circumstances where exercise leads to a decrease of circulating androgens. We suggest that those changes have significant impact on female physiology and physical performance.

Exercise-induced cardioprotection--biochemical, morphological and functional evidence in whole tissue and isolated mitochondria.

PubMed

Ascensão, António; Ferreira, Rita; Magalhães, José

2007-04-12

Myocardial injury is a major contributor to the morbidity and mortality associated with coronary artery disease. Regular exercise has been confirmed as a pragmatic countermeasure to protect against cardiac injury. Specifically, endurance exercise has been proven to provide cardioprotection against cardiac insults in both young and old animals. Proposed mechanisms to explain the cardioprotective effects of exercise are mediated, at least partially, by redox changes and include the induction of myocardial heat shock proteins, improved cardiac antioxidant capacity, and/or elevation of other cardioprotective molecules. Understanding the molecular basis for exercise-induced cardioprotection is important in developing exercise strategies to protect the heart during and after insults. Data suggest that these positive modulator effects occur at different levels of cellular organization, being mitochondria fundamental organelles that are sensitive to disturbances imposed by exercise on basal homeostasis. At present, which of these protective mechanisms is essential for exercise-induced cardioprotection remains unclear. This review analyzes the biochemical, morphological and functional outcomes of acute and chronic exercise on the overall cardiac muscle tissue and in isolated mitochondria. Some redox-based mechanisms behind the cross-tolerance effects particularly induced by endurance training, against certain stressors responsible for the impairments in cardiac homeostasis caused by aging, diabetes, drug administration or ischemia-reperfusion are also outlined. Further work should be addressed in order to clarify the precise regulatory mechanisms by which physical exercise augments heart tolerance against many cardiotoxic agents.

Eucapnic voluntary hyperventilation in diagnosing exercise-induced laryngeal obstructions.

PubMed

Christensen, Pernille M; Rasmussen, Niels

2013-11-01

Exercise-induced laryngeal obstructions (EILOs) cause exercise-related respiratory symptoms (ERRS) and are important differential diagnoses to exercise-induced asthma. The diagnostic method for EILOs includes provocation to induce the obstruction followed by a verification of the obstruction and the degree thereof. The objective of the present study was to examine if a eucapnic voluntary hyperventilation (EVH) test could induce laryngeal obstructions laryngoscopically identical in subtypes and development as seen during an exercise test. EVH and exercise testing with continuous laryngoscopy were performed during a screening of two national athletic teams (n = 67). The laryngoscopic recordings were examined for usability, abnormalities and maximal supraglottic and glottic obstruction using two currently available methods (Eilomea and CLE-score). The participants were asked questions on ERRS, and whether the symptoms experienced during each provocation matched those experienced during regular training. A total of 39 completed both tests. There were no significant differences in subtypes and development thereof, the experience of symptoms, and specificity and sensitivity between the methods. Significantly more recordings obtained during the exercise test were usable for evaluation primarily due to resilient mucus on the tip of the fiber-laryngoscope in the EVH test. Only recordings of six athletes from both provocation methods were usable for evaluation using the Eilomea method (high-quality demand). Amongst these, a linear correlation was found for the glottic obstruction. EVH tests can induce EILOs. However, the present test protocol needs adjustments to secure better visualisation of the larynx during provocation.

Menstrual dysfunction in athletes: assessment and treatment.

PubMed

Patterson, D F

1995-01-01

The reported incidence of exercise induced menstrual dysfunction varies among adolescent athletes from 12% to 66%. Women who experience amenorrhea associated with exercise are at risk for irretrievable bone mineral density loss and increased rate of stress fractures. Nurses should provide information to parents, coaches, and athletes about changes in exercise intensity and frequency, dietary modifications, and estrogen and progesterone replacement therapy to minimize the sequelae of exercise induced menstrual dysfunction.

Understanding Key Mechanisms of Exercise-Induced Cardiac Protection to Mitigate Disease: Current Knowledge and Emerging Concepts.

PubMed

Bernardo, Bianca C; Ooi, Jenny Y Y; Weeks, Kate L; Patterson, Natalie L; McMullen, Julie R

2018-01-01

The benefits of exercise on the heart are well recognized, and clinical studies have demonstrated that exercise is an intervention that can improve cardiac function in heart failure patients. This has led to significant research into understanding the key mechanisms responsible for exercise-induced cardiac protection. Here, we summarize molecular mechanisms that regulate exercise-induced cardiac myocyte growth and proliferation. We discuss in detail the effects of exercise on other cardiac cells, organelles, and systems that have received less or little attention and require further investigation. This includes cardiac excitation and contraction, mitochondrial adaptations, cellular stress responses to promote survival (heat shock response, ubiquitin-proteasome system, autophagy-lysosomal system, endoplasmic reticulum unfolded protein response, DNA damage response), extracellular matrix, inflammatory response, and organ-to-organ crosstalk. We summarize therapeutic strategies targeting known regulators of exercise-induced protection and the challenges translating findings from bench to bedside. We conclude that technological advancements that allow for in-depth profiling of the genome, transcriptome, proteome and metabolome, combined with animal and human studies, provide new opportunities for comprehensively defining the signaling and regulatory aspects of cell/organelle functions that underpin the protective properties of exercise. This is likely to lead to the identification of novel biomarkers and therapeutic targets for heart disease.

Calculation algorithms for breath-by-breath alveolar gas exchange: the unknowns!

PubMed

Golja, Petra; Cettolo, Valentina; Francescato, Maria Pia

2018-06-25

Several papers (algorithm papers) describe computational algorithms that assess alveolar breath-by-breath gas exchange by accounting for changes in lung gas stores. It is unclear, however, if the effects of the latter are actually considered in literature. We evaluated dissemination of algorithm papers and the relevant provided information. The list of documents investigating exercise transients (in 1998-2017) was extracted from Scopus database. Documents citing the algorithm papers in the same period were analyzed in full text to check consistency of the relevant information provided. Less than 8% (121/1522) of documents dealing with exercise transients cited at least one algorithm paper; the paper of Beaver et al. (J Appl Physiol 51:1662-1675, 1981) was cited most often, with others being cited tenfold less. Among the documents citing the algorithm paper of Beaver et al. (J Appl Physiol 51:1662-1675, 1981) (N = 251), only 176 cited it for the application of their algorithm/s; in turn, 61% (107/176) of them stated the alveolar breath-by-breath gas exchange measurement, but only 1% (1/107) of the latter also reported the assessment of volunteers' functional residual capacity, a crucial parameter for the application of the algorithm. Information related to gas exchange was provided consistently in the methods and in the results in 1 of the 107 documents. Dissemination of algorithm papers in literature investigating exercise transients is by far narrower than expected. The information provided about the actual application of gas exchange algorithms is often inadequate and/or ambiguous. Some guidelines are provided that can help to improve the quality of future publications in the field.

Real-time 1-D/2-D transient elastography on a standard ultrasound scanner using mechanically induced vibration.

PubMed

Azar, Reza Zahiri; Dickie, Kris; Pelissier, Laurent

2012-10-01

Transient elastography has been well established in the literature as a means of assessing the elasticity of soft tissue. In this technique, tissue elasticity is estimated from the study of the propagation of the transient shear waves induced by an external or internal source of vibration. Previous studies have focused mainly on custom single-element transducers and ultrafast scanners which are not available in a typical clinical setup. In this work, we report the design and implementation of a transient elastography system on a standard ultrasound scanner that enables quantitative assessment of tissue elasticity in real-time. Two new custom imaging modes are introduced that enable the system to image the axial component of the transient shear wave, in response to an externally induced vibration, in both 1-D and 2-D. Elasticity reconstruction algorithms that estimate the tissue elasticity from these transient waves are also presented. Simulation results are provided to show the advantages and limitations of the proposed system. The performance of the system is also validated experimentally using a commercial elasticity phantom.

Colostrum supplementation protects against exercise - induced oxidative stress in skeletal muscle in mice

PubMed Central

2012-01-01

Background This study examined the effects of bovine colostrum on exercise –induced modulation of antioxidant parameters in skeletal muscle in mice. Adult male BALB/c mice were randomly divided into four groups (control, colostrum alone, exercise and exercise with colostrum) and each group had three subgroups (day 0, 21 and 42). Colostrum groups of mice were given a daily oral supplement of 50 mg/kg body weight of bovine colostrum and the exercise group of mice were made to exercise on the treadmill for 30 minutes per day. Total antioxidants, lipid hydroperoxides, xanthine oxidase and super oxide dismutase level was assayed from the homogenate of hind limb skeletal muscle. Results Exercise—induced a significant oxidative stress in skeletal muscles as evidenced by the elevated lipid hydroperoxides and xanthine oxidase levels. There was a significant decrease in skeletal muscle total antioxidants and superoxide dismutase levels. Daily colostrum supplement significantly reduced the lipid hydroperoxides and xanthine oxidase enzyme level and increased the total antioxidant levels in the leg muscle. Conclusion Thus, the findings of this study showed that daily bovine colostrum supplementation was beneficial to skeletal muscle to reduce the oxidant-induced damage during muscular exercise. PMID:23173926

Exercise training attenuated chronic cigarette smoking-induced up-regulation of FIZZ1/RELMα in lung of rats.

PubMed

Ma, Wan-li; Cai, Peng-cheng; Xiong, Xian-zhi; Ye, Hong

2013-02-01

FIZZ/RELM is a new gene family named "found in inflammatory zone" (FIZZ) or "resistin-like molecule" (RELM). FIZZ1/RELMα is specifically expressed in lung tissue and associated with pulmonary inflammation. Chronic cigarette smoking up-regulates FIZZ1/RELMα expression in rat lung tissues, the mechanism of which is related to cigarette smoking-induced airway hyperresponsiveness. To investigate the effect of exercise training on chronic cigarette smoking-induced airway hyperresponsiveness and up-regulation of FIZZ1/RELMα, rat chronic cigarette smoking model was established. The rats were treated with regular exercise training and their airway responsiveness was measured. Hematoxylin and eosin (HE) staining, immunohistochemistry and in situ hybridization of lung tissues were performed to detect the expression of FIZZ1/RELMα. Results revealed that proper exercise training decreased airway hyperresponsiveness and pulmonary inflammation in rat chronic cigarette smoking model. Cigarette smoking increased the mRNA and protein levels of FIZZ1/RELMα, which were reversed by the proper exercise. It is concluded that proper exercise training prevents up-regulation of FIZZ1/RELMα induced by cigarette smoking, which may be involved in the mechanism of proper exercise training modulating airway hyperresponsiveness.

A pulse of blue light induces a transient increase in activity of apoplastic K+ in laminar pulvinus of Phaseolus vulgaris L.

PubMed

Okazaki, Y; Azuma, K; Nishizaki, Y

2000-02-01

A pulse of blue light induced both a transient increase in activity of apoplastic K+ and membrane depolarization in laminar pulvinus of Phaseolus vulgaris L. This shows that blue-light-induced net efflux of K+ from motor cells is closely related to membrane depolarization.

Continuation of Exercise Is Necessary to Inhibit High Fat Diet-Induced β-Amyloid Deposition and Memory Deficit in Amyloid Precursor Protein Transgenic Mice

PubMed Central

Maesako, Masato; Uemura, Kengo; Iwata, Ayana; Kubota, Masakazu; Watanabe, Kiwamu; Uemura, Maiko; Noda, Yasuha; Asada-Utsugi, Megumi; Kihara, Takeshi; Takahashi, Ryosuke; Shimohama, Shun; Kinoshita, Ayae

2013-01-01

High fat diet (HFD) is prevalent in many modern societies and HFD-induced metabolic condition is a growing concern worldwide. It has been previously reported that HFD clearly worsens cognitive function in amyloid precursor protein (APP) transgenic mice. On the other hand, we have demonstrated that voluntary exercise in an enriched environment is an effective intervention to rescue HFD-induced β-amyloid (Aβ) deposition and memory deficit. However, it had been unclear whether consumption of HFD after exercising abolished the beneficial effect of exercise on the inhibition of Alzheimer's disease (AD) pathology. To examine this question, we exposed wild type (WT) and APP mice fed with HFD to exercise conditions at different time periods. In our previous experiment, we gave HFD to mice for 20 weeks and subjected them to exercise during weeks 10–20. In the present study, mice were subjected to exercise conditions during weeks 0–10 or weeks 5–15 while being on HFD. Interestingly, we found that the effect of exercise during weeks 0–10 or weeks 5–15 on memory function was not abolished in WT mice even if they kept having HFD after finishing exercise. However, in APP transgenic mice, HFD clearly disrupted the effect of exercise during weeks 0–10 or weeks 5–15 on memory function. Importantly, we observed that the level of Aβ oligomer was significantly elevated in the APP mice that exercised during weeks 0–10: this might have been caused by the up-regulation of Aβ production. These results provide solid evidence that continuation of exercise is necessary to rescue HFD-induced aggravation of cognitive decline in the pathological setting of AD. PMID:24023774

Aerobic exercise training-induced changes in serum adropin level are associated with reduced arterial stiffness in middle-aged and older adults.

PubMed

Fujie, Shumpei; Hasegawa, Natsuki; Sato, Koji; Fujita, Satoshi; Sanada, Kiyoshi; Hamaoka, Takafumi; Iemitsu, Motoyuki

2015-11-15

Aging-induced arterial stiffening is reduced by aerobic exercise training, and elevated production of nitric oxide (NO) participates in this effect. Adropin is a regulator of endothelial NO synthase and NO release, and circulating adropin level decreases with age. However, the effect of habitual aerobic exercise on circulating adropin levels in healthy middle-aged and older adults remains unclear. We sought to determine whether serum adropin level is associated with exercise training-induced changes in arterial stiffness. First, in a cross-sectional study, we investigated the association between serum adropin level and both arterial stiffness and cardiorespiratory fitness in 80 healthy middle-aged and older subjects (65.6 ± 0.9 yr). Second, in an intervention study, we examined the effects of 8-wk aerobic exercise training on serum adropin level and arterial stiffness in 40 healthy middle-aged and older subjects (67.3 ± 1.0 yr) divided into two groups: aerobic exercise training and sedentary controls. In the cross-sectional study, serum adropin level was negatively correlated with carotid β-stiffness (r = -0.437, P < 0.001) and positively correlated with plasma NOx level (r = 0.493, P < 0.001) and cardiorespiratory fitness (r = 0.457, P < 0.001). Serum adropin levels were elevated after the 8-wk aerobic exercise training intervention, and training-induced changes in serum adropin level were correlated with training-induced changes in carotid β-stiffness (r = -0.399, P < 0.05) and plasma NOx level (r = 0.623, P < 0.001). Thus the increase in adropin may participate in the exercise-induced reduction of arterial stiffness. Copyright © 2015 the American Physiological Society.

Efflux of creatine kinase from isolated soleus muscle depends on age, sex and type of exercise in mice.

PubMed

Baltusnikas, Juozas; Venckunas, Tomas; Kilikevicius, Audrius; Fokin, Andrej; Ratkevicius, Aivaras

2015-06-01

Elevated plasma creatine kinase (CK) activity is often used as an indicator of exercise-induced muscle damage. Our aim was to study effects of contraction type, sex and age on CK efflux from isolated skeletal muscles of mice. The soleus muscle (SOL) of adult (7.5-month old) female C57BL/6J mice was subjected to either 100 passive stretches, isometric contractions or eccentric contractions, and muscle CK efflux was assessed after two-hour incubation in vitro. SOL of young (3-month old) male and female mice was studied after 100 eccentric contractions. For adult females, muscle CK efflux was larger (p < 0.05) after eccentric contractions than after incubation without exercise (698 ± 344 vs. 268 ± 184 mU·h(-1), respectively), but smaller (p < 0.05) than for young females after the same type of exercise (1069 ± 341 mU·h(-1)). Eccentric exercise-induced CK efflux was larger in muscles of young males compared to young females (2046 ± 317 vs 1069 ± 341 mU · h(-1), respectively, p < 0.001). Our results show that eccentric contractions induce a significant increase in muscle CK efflux immediately after exercise. Isolated muscle resistance to exercise-induced CK efflux depends on age and sex of mice. Key pointsMuscle lengthening contractions induce the highest CK efflux in vitro compared with similar protocol of isometric contractions or passive stretches.Muscle CK efflux in vitro is applicable in studying changes of sarcolemma permeability/integrity, a proxy of muscle damage, in response to muscle contractile activity.Isolated muscle resistance to exercise-induced CK efflux is greater in female compared to male mice of young age and is further increased in adult female mice.

Efflux of Creatine Kinase from Isolated Soleus Muscle Depends on Age, Sex and Type of Exercise in Mice

PubMed Central

Baltusnikas, Juozas; Venckunas, Tomas; Kilikevicius, Audrius; Fokin, Andrej; Ratkevicius, Aivaras

2015-01-01

Elevated plasma creatine kinase (CK) activity is often used as an indicator of exercise-induced muscle damage. Our aim was to study effects of contraction type, sex and age on CK efflux from isolated skeletal muscles of mice. The soleus muscle (SOL) of adult (7.5-month old) female C57BL/6J mice was subjected to either 100 passive stretches, isometric contractions or eccentric contractions, and muscle CK efflux was assessed after two-hour incubation in vitro. SOL of young (3-month old) male and female mice was studied after 100 eccentric contractions. For adult females, muscle CK efflux was larger (p < 0.05) after eccentric contractions than after incubation without exercise (698 ± 344 vs. 268 ± 184 mU·h−1, respectively), but smaller (p < 0.05) than for young females after the same type of exercise (1069 ± 341 mU·h−1). Eccentric exercise-induced CK efflux was larger in muscles of young males compared to young females (2046 ± 317 vs 1069 ± 341 mU · h−1, respectively, p < 0.001). Our results show that eccentric contractions induce a significant increase in muscle CK efflux immediately after exercise. Isolated muscle resistance to exercise-induced CK efflux depends on age and sex of mice. Key points Muscle lengthening contractions induce the highest CK efflux in vitro compared with similar protocol of isometric contractions or passive stretches. Muscle CK efflux in vitro is applicable in studying changes of sarcolemma permeability/integrity, a proxy of muscle damage, in response to muscle contractile activity. Isolated muscle resistance to exercise-induced CK efflux is greater in female compared to male mice of young age and is further increased in adult female mice. PMID:25983588

Transient coherence of media under strong phase modulation exploiting electromagnetically induced transparency

NASA Astrophysics Data System (ADS)

Shwa, David; Katz, Nadav

2014-08-01

When quantum systems are shifted faster than their transition and coupling time scales, their susceptibility is dramatically modified. We measure the optical susceptibility of a strongly modulated electromagnetically induced transparency system. Time vs detuning plots for different pump modulation frequencies reveal a transition between an adiabatic regime where a series of smooth pulses are created and a nonadiabatic regime where a strong transient oscillating response is added. Applying a magnetic field lifts the hyperfine level degeneracy, revealing an interference effect between the different magnetic level transients. We explore the dynamics of the magnetic and nonmagnetic cases and discuss their coherent nature. We finally combine the global phase of the transmitted pulses with the transient interference to achieve broadband magnetic sensing without losing the sensitivity of a single electromagnetically induced transparency line.

Physiological aspects of a vocal exercise.

PubMed

Elliot, N; Sundberg, J; Gramming, P

1997-06-01

The physiological aim of vocal exercises is mostly understood in intuitive terms only. This article presents an attempt to document the phonatory behavior induced by a vocal exercise. An elevated vertical position of the larynx is frequently associated with hyperfunctional phonatory habits, presumably because it induces an exaggerated vocal fold adduction. Using the multichannel electroglottograph (MEGG), the laryngeal position was determined in a group of subjects who performed a voice exercise that contained extremely prolonged versions of the consonant/b:/. This exercise is used by the coauthor (N.E.) as part of a standard vocal exercise program. Two of the seven subjects were dysphonic phonastenic patients, and the rest were normal trained or untrained persons. Different attempts to calibrate the MEGG confirmed a linear relationship with larynx height, provided electrode positioning was correct. The results showed that the exercise induced substantial vertical displacements of the larynx. Comparison with larynx height during voicing of other consonants showed that the/b/, in particular, tended to lower the larynx.

An Examination of Exercise-Induced Feeling States and Their Association With Future Participation in Physical Activity Among Older Adults.

PubMed

Brunet, Jennifer; Guérin, Eva; Speranzini, Nicolas

2018-01-01

Although exercise-induced feeling states may play a role in driving future behavior, their role in relation to older adults' participation in physical activity (PA) has seldom been considered. The objectives of this study were to describe changes in older adults' feeling states during exercise, and examine if levels of and changes in feeling states predicted their future participation in PA. Self-reported data on feeling states were collected from 82 older adults immediately before, during, and after a moderate-intensity exercise session, and on participation in PA 1 month later. Data were analyzed using latent growth modeling. Feelings of revitalization, positive engagement, and tranquility decreased during exercise, whereas feelings of physical exhaustion increased. Feelings of revitalization immediately before the exercise session predicted future participation in PA; changes in feeling states did not. This study does not provide empirical evidence that older adults' exercise-induced feeling states predict their future participation in PA.

Effect of BCAA supplement timing on exercise-induced muscle soreness and damage: a pilot placebo-controlled double-blind study.

PubMed

Ra, Song-Gyu; Miyazaki, Teruo; Kojima, Ryo; Komine, Shoichi; Ishikura, Keisuke; Kawanaka, Kentaro; Honda, Akira; Matsuzaki, Yasushi; Ohmori, Hajime

2017-09-22

The aim of present study was to compare the effects of branched-chain amino acid (BCAA) supplementation taken before or after exercise on delayed onset muscle soreness (DOMS) and exercise-induced muscle damage (EIMD). Fifteen young men (aged 21.5 ± 0.4 years) were given either BCAA (9.6 g·day-1) or placebo before and after exercise (and for 3 days prior to and following the exercise day) in three independent groups: the Control group (placebo before and after exercise), the PRE group (BCAA before exercise and placebo after exercise), and the POST group (placebo before exercise and BCAA after exercise). Participants performed 30 repetitions of eccentric exercise with the non-dominant arm. DOMS, upper arm circumference (CIR), elbow range of motion (ROM), serum creatine kinase (CK), lactate dehydrogenase (LDH), and aldolase, BCAA, and Beta-hydroxy-Beta-methylbutyrate (3HMB) were measured immediately before and after the exercise and on the following 4 days. Serum BCAA and 3HMB concentrations increased significantly in the PRE group immediately after the exercise, recovering to baseline over the following days. In the days following the exercise day, DOMS, CIR, and ROM were significantly improved in the PRE group compared to the Control group, with weaker effects in the POST group. Serum activities of CK, LDH, and aldolase in the days following the exercise day were significantly suppressed in the PRE group compared to Control group. Present study confirmed that repeated BCAA supplementation before exercise had a more beneficial effect in attenuating DOMS and EIMD induced by eccentric exercise than repeated supplementation after exercise.

ALDH2 restores exhaustive exercise-induced mitochondrial dysfunction in skeletal muscle

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Qiuping; Zheng, Jianheng; Qiu, Jun

Background: Mitochondrial aldehyde dehydrogenase 2 (ALDH2) is highly expressed in heart and skeletal muscles, and is the major enzyme that metabolizes acetaldehyde and toxic aldehydes. The cardioprotective effects of ALDH2 during cardiac ischemia/reperfusion injury have been recognized. However, less is known about the function of ALDH2 in skeletal muscle. This study was designed to evaluate the effect of ALDH2 on exhaustive exercise-induced skeletal muscle injury. Methods: We created transgenic mice expressing ALDH2 in skeletal muscles. Male wild-type C57/BL6 (WT) and ALDH2 transgenic mice (ALDH2-Tg), 8-weeks old, were challenged with exhaustive exercise for 1 week to induce skeletal muscle injury. Animalsmore » were sacrificed 24 h post-exercise and muscle tissue was excised. Results: ALDH2-Tg mice displayed significantly increased treadmill exercise capacity compared to WT mice. Exhaustive exercise caused an increase in mRNA levels of the muscle atrophy markers, Atrogin-1 and MuRF1, and reduced mitochondrial biogenesis and fusion in WT skeletal muscles; these effects were attenuated in ALDH2-Tg mice. Exhaustive exercise also enhanced mitochondrial autophagy pathway activity, including increased conversion of LC3-I to LC3-II and greater expression of Beclin1 and Bnip3; the effects of which were mitigated by ALDH2 overexpression. In addition, ALDH2-Tg reversed the increase of an oxidative stress biomarker (4-hydroxynonenal) and decreased levels of mitochondrial antioxidant proteins, including manganese superoxide dismutase and NAD(P)H:quinone oxidoreductase 1, in skeletal muscle induced by exhaustive exercise. Conclusion: ALDH2 may reverse skeletal muscle mitochondrial dysfunction due to exhaustive exercise by regulating mitochondria dynamic remodeling and enhancing the quality of mitochondria. - Highlights: • Skeletal muscle ALDH2 expression and activity declines during exhaustive exercise. • ALDH2 overexpression enhances physical performance and restores muscle atrophy. • ALDH2 overexpression attenuates exercise-induced mitochondrial oxidative stress.« less

Quality of Life after Diet or Exercise-Induced Weight Loss in Overweight to Obese Postmenopausal Women: The SHAPE-2 Randomised Controlled Trial.

PubMed

van Gemert, Willemijn A M; van der Palen, Job; Monninkhof, Evelyn M; Rozeboom, Anouk; Peters, Roelof; Wittink, Harriet; Schuit, Albertine J; Peeters, Petra H

2015-01-01

This study investigates the effect of a modest weight loss either by a calorie restricted diet or mainly by increased physical exercise on health related quality of life (HRQoL) in overweight-to-obese and inactive postmenopausal women. We hypothesize that HRQoL improves with weight loss, and that exercise-induced weight loss is more effective for this than diet-induced weight loss. The SHAPE-2 trial was primarily designed to evaluate any additional effect of weight loss by exercise compared with a comparable amount of weight loss by diet on biomarkers relevant for breast cancer risk. In the present analysis we focus on HRQoL. We randomly assigned 243 eligible women to a diet (n = 97), exercise (n = 98), or control group (n = 48). Both interventions aimed for 5-6 kg weight loss. HRQoL was measured at baseline and after 16 weeks by the SF-36 questionnaire. Data of 214 women were available for analysis. Weight loss was 4.9 kg (6.1%) and 5.5 kg (6.9%) with diet and exercise, respectively. Scores of the SF-36 domain 'health change' increased significantly by 8.8 points (95% CI 1.6;16.1) with diet, and by 20.5 points (95% CI 13.2;27.7) with exercise when compared with control. Direct comparison of diet and exercise showed a statistically significantly stronger improvement with exercise. Both intervention groups showed a tendency towards improvements in most other domains, which were more pronounced in the exercise group, but not statistically different from control or each other. In a randomized trial in overweight-to-obese and inactive postmenopausal women a comparable 6%-7% weight loss was achieved by diet-only or mainly by exercise and showed improvements in physical and mental HRQoL domains, but results were not statistically significant in either the diet or exercise group. However, a modest weight loss does lead to a positive change in self-perceived health status. This effect was significantly larger with exercise-induced weight loss than with comparable diet-induced weight loss. ClinicalTrials.gov NCT01511276.

The SEM description of interaction of a transient electromagnetic wave with an object

NASA Technical Reports Server (NTRS)

Pearson, L. W.; Wilton, D. R.

1980-01-01

The singularity expansion method (SEM), proposed as a means for determining and representing the transient surface current density induced on a scatterer by a transient electromagnetic wave is described. The resulting mathematical description of the transient surface current on the object is discussed. The data required to represent the electromagnetic scattering properties of a given object are examined. Experimental methods which were developed for the determination of the SEM description are discussed. The feasibility of characterizing the surface current induced on aircraft flying in proximity to a lightning stroke by way of SEM is examined.

Does a Rehabilitation Program of Aerobic and Progressive Resisted Exercises Influence HIV-Induced Distal Neuropathic Pain?

PubMed

Maharaj, Sonill S; Yakasai, Abdulsalam M

2018-05-01

Distal symmetrical polyneuropathy is a common neurological sequela after HIV, which leads to neuropathic pain and functional limitations. Rehabilitation programs with exercises are used to augment pharmacological therapy to relieve pain but appropriate and effective exercises are unknown. This study explored the safety and effect of moderate-intensity aerobic exercises and progressive resisted exercises for HIV-induced distal symmetrical polyneuropathy neuropathic pain. A randomized pretest, posttest of 12 wks of aerobic exercise or progressive resisted exercise compared with a control. Outcome measures were assessed using the subjective periphery neuropathy, brief peripheral neuropathy screening, and numeric pain rating scale. Pain was assessed at baseline, 6 and 12 wks. Data between groups were compared using Kruskal-Wallis, Mann-Whitney U test, and within-groups Friedman and Wilcoxon signed rank tests. There were 136 participants (mean [SD] age = 36.79 [8.23] yrs) and the exercise groups completed the protocols without any adverse effects. Pain scores within and between aerobic exercise and progressive resisted exercise groups showed significant improvement (P < 0.05) from baseline to 6 and 12 wks compared with the control (P > 0.05). This study supports a rehabilitation program of moderate-intensity aerobic exercise and progressive resisted exercise being safe and effective for reducing neuropathic pain and is beneficial with analgesics for HIV-induced distal symmetrical polyneuropathy.

Pathophysiological mechanisms of exercise-induced anaphylaxis: an EAACI position statement.

PubMed

Ansley, L; Bonini, M; Delgado, L; Del Giacco, S; Du Toit, G; Khaitov, M; Kurowski, M; Hull, J H; Moreira, A; Robson-Ansley, P J

2015-10-01

This document is the result of a consensus on the mechanisms of exercise-induced anaphylaxis (EIAn), an unpredictable and potentially fatal syndrome. A multidisciplinary panel of experts including exercise physiologists, allergists, lung physicians, paediatricians and a biostatistician reached the given consensus. Exercise-induced anaphylaxis (EIAn) describes a rare and potentially fatal syndrome in which anaphylaxis occurs in conjunction with exercise. The pathophysiological mechanisms underlying EIAn have not yet been elucidated although a number of hypotheses have been proposed. This review evaluates the validity of each of the popular theories in relation to exercise physiology and immunology. On the basis of this evidence, it is concluded that proposed mechanisms lack validity, and it is recommended that a global research network is developed with a common approach to the diagnosis and treatment of EIAn in order to gain sufficient power for scientific evaluation. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

The mechanism of transient myopia induced by sulfonamide therapy.

PubMed

Bovino, J A; Marcus, D F

1982-07-01

We performed acute and convalescent A-scan echographic ocular measurements documenting the anterior chamber depth, lens thickness, and axial length of a patient with acute transient sulfamethoxazole-induced myopia. Shallowing of the anterior chamber, independent of changes in the thickness of the lens, was the only anatomic variation found that could explain the myopia. Swelling of the ciliary body, with forward movement of the lens-iris diaphragm, could produce this transient anatomic change.

Blunted Myoglobin and Quadriceps Soreness after Electrical Stimulation during the Luteal Phase or Oral Contraception

ERIC Educational Resources Information Center

Anderson, Lindsey J.; Baker, Lucinda L.; Schroeder, E. Todd

2017-01-01

Purpose: Acute muscle damage after exercise triggers subsequent regeneration, leading to hypertrophy and increased strength after repeated exercise. It has been debated whether acute exercise-induced muscle damage is altered under various premenopausal estrogen conditions. Acute contraction-induced muscle damage was compared during exogenous (oral…

Exercise-induced menstrual dysfunction.

PubMed

Henley, K; Vaitukaitis, J L

1988-01-01

Menstrual cycle changes associated with vigorous exercise can range widely. They may be only subtle abnormalities, ranging from delayed onset of spontaneous menses or anovulatory cycles to loss of spontaneous menses. They may be more serious, however. Significant adverse bone mineral changes, resulting in clinically significant osteoporosis and fractures, may occur concomitantly with exercise-induced menstrual dysfunction.

Vitamin E and vitamin C do not reduce insulin sensitivity but inhibit mitochondrial protein expression in exercising obese rats

USDA-ARS?s Scientific Manuscript database

Controversy exists as to whether supplementation with the antioxidants vitamin E (VE) and vitamin C (VC) blocks adaptation to exercise. Exercise is a first-line means to treat obesity and its complications. While diet-induced obesity alters mitochondrial (MT) function and induces insulin resistance ...

Exercise-induced pulmonary hemorrhage in barrel racing horses in the Pacific Northwest region of the United States

USDA-ARS?s Scientific Manuscript database

Background: Exercise-induced pulmonary hemorrhage (EIPH) refers to bleeding from the lungs in association with strenuous exercise. It has been documented in race horses but little information exists on EIPH in barrel racing horses. Hypothesis/Objectives: Our goals were to evaluate the presence of EI...

Vitamin E does not prevent exercise-induced increase in pulmonary clearance.

PubMed

Lorino, A M; Paul, M; Cocea, L; Scherrer-Crosbie, M; Dahan, E; Meignan, M; Atlan, G

1994-11-01

It has been observed that sustained exercise results in a prolonged increase in alveolar epithelial permeability, as assessed by the pulmonary clearance rate of aerosolized 99mTc-labeled diethylenetriaminepentaacetate (Lorino et al. J. Appl. Physiol. 67: 2055-2059, 1989). The involvement of lipid peroxidation in this increased permeability was tested in seven nonsmoking volunteers by comparing the exercise-induced increases in pulmonary 99mTc-diethylenetriaminepentaacetate clearance before and after a 3-wk supplementation with oral vitamin E (1,000 IU/day), according to a protocol designed as a single-blind crossover study. The 60-min exercise was performed on a treadmill at a constant load corresponding to 80% of maximal O2 uptake. Administration of vitamin E, a very important antioxidant, did not reduce the exercise-induced increase in lung clearance, suggesting that the exercise-induced increase in lung epithelial permeability does not primarily result from the occurrence of lipid peroxidation in the alveolar membrane. This result thus corroborates the hypothesis of an alteration of the intercellular tight junctions due to the mechanical effects of hyperventilation.

Effects of exercise on leukocyte death: prevention by hydrolyzed whey protein enriched with glutamine dipeptide.

PubMed

Cury-Boaventura, Maria Fernanda; Levada-Pires, Adriana C; Folador, Alessandra; Gorjão, Renata; Alba-Loureiro, Tatiana C; Hirabara, Sandro M; Peres, Fabiano P; Silva, Paulo R S; Curi, Rui; Pithon-Curi, Tania C

2008-06-01

Lymphocyte and neutrophil death induced by exercise and the role of hydrolyzed whey protein enriched with glutamine dipeptide (Gln) supplementation was investigated. Nine triathletes performed two exhaustive exercise trials with a 1-week interval in a randomized, double blind, crossover protocol. Thirty minutes before treadmill exhaustive exercise at variable speeds in an inclination of 1% the subjects ingested 50 g of maltodextrin (placebo) or 50 g of maltodextrin plus 4 tablets of 700 mg of hydrolyzed whey protein enriched with 175 mg of glutamine dipeptide dissolved in 250 mL water. Cell viability, DNA fragmentation, mitochondrial transmembrane potential and production of reactive oxygen species (ROS) were determined in lymphocytes and neutrophils. Exhaustive exercise decreased viable lymphocytes but had no effect on neutrophils. A 2.2-fold increase in the proportion of lymphocytes and neutrophils with depolarized mitochondria was observed after exhaustive exercise. Supplementation of maltodextrin plus Gln (MGln) prevented the loss of lymphocyte membrane integrity and the mitochondrial membrane depolarization induced by exercise. Exercise caused an increase in ROS production by neutrophils, whereas supplementation of MGln had no additional effect. MGln supplementation partially prevented lymphocyte apoptosis induced by exhaustive exercise possibly by a protective effect on mitochondrial function.

Exercise for the heart: signaling pathways

PubMed Central

Zhang, Haifeng; Xiao, Junjie; Li, Xinli

2015-01-01

Physical exercise, a potent functional intervention in protecting against cardiovascular diseases, is a hot topic in recent years. Exercise has been shown to reduce cardiac risk factors, protect against myocardial damage, and increase cardiac function. This improves quality of life and decreases mortality and morbidity in a variety of cardiovascular diseases, including myocardial infarction, cardiac ischemia/reperfusion injury, diabetic cardiomyopathy, cardiac aging, and pulmonary hypertension. The cellular adaptation to exercise can be associated with both endogenous and exogenous factors: 1) exercise induces cardiac growth via hypertrophy and renewal of cardiomyocytes, and 2) exercise induces endothelial progenitor cells to proliferate, migrate and differentiate into mature endothelial cells, giving rise to endothelial regeneration and angiogenesis. The cellular adaptations associated with exercise are due to the activation of several signaling pathways, in particular, the growth factor neuregulin1 (NRG1)-ErbB4-C/EBPβ and insulin-like growth factor (IGF)-1-PI3k-Akt signaling pathways. Of interest, microRNAs (miRNAs, miRs) such as miR-222 also play a major role in the beneficial effects of exercise. Thus, exploring the mechanisms mediating exercise-induced benefits will be instrumental for devising new effective therapies against cardiovascular diseases. PMID:26318584

Impact of endothelin blockade on acute exercise-induced changes in blood flow and endothelial function in type 2 diabetes mellitus.

PubMed

Schreuder, Tim H A; van Lotringen, Jaap H; Hopman, Maria T E; Thijssen, Dick H J

2014-09-01

Positive vascular effects of exercise training are mediated by acute increases in blood flow. Type 2 diabetes patients show attenuated exercise-induced increases in blood flow, possibly mediated by the endothelin pathway, preventing an optimal stimulus for vascular adaptation. We examined the impact of endothelin receptor blockade (bosentan) on exercise-induced blood flow in the brachial artery and on pre- and postexercise endothelial function in type 2 diabetes patients (n = 9, 60 ± 7 years old) and control subjects (n = 10, 60 ± 5 years old). Subjects reported twice to the laboratory to perform hand-grip exercise in the presence of endothelin receptor blockade or placebo. We examined brachial artery endothelial function (via flow-mediated dilatation) before and after exercise, as well as blood flow during exercise. Endothelin receptor blockade resulted in a larger increase in blood flow during exercise in type 2 diabetes patients (P = 0.046), but not in control subjects (P = 0.309). Exercise increased shear rate across the exercise protocol, unaffected by endothelin receptor blockade. Exercise did not alter brachial artery diameter in either group, but endothelin receptor blockade resulted in a larger brachial artery diameter in type 2 diabetes patients (P = 0.033). Exercise significantly increased brachial artery flow-mediated dilatation in both groups, unaffected by endothelin receptor blockade. Endothelin receptor blockade increased exercise-induced brachial artery blood flow in type 2 diabetes patients, but not in control subjects. Despite this effect of endothelin receptor blockade on blood flow, we found no impact on baseline or post-exercise endothelial function in type 2 diabetes patients or control subjects, possibly related to normalization of the shear stimulus during exercise. The successful increase in blood flow during exercise in type 2 diabetes patients through endothelin receptor blockade may have beneficial effects in repeated exercise training. © 2014 The Authors. Experimental Physiology © 2014 The Physiological Society.

Exercise improves mitochondrial and redox-regulated stress responses in the elderly: better late than never!

PubMed

Cobley, James N; Moult, Peter R; Burniston, Jatin G; Morton, James P; Close, Graeme L

2015-04-01

Ageing is associated with several physiological declines to both the cardiovascular (e.g. reduced aerobic capacity) and musculoskeletal system (muscle function and mass). Ageing may also impair the adaptive response of skeletal muscle mitochondria and redox-regulated stress responses to an acute exercise bout, at least in mice and rodents. This is a functionally important phenomenon, since (1) aberrant mitochondrial and redox homeostasis are implicated in the pathophysiology of musculoskeletal ageing and (2) the response to repeated exercise bouts promotes exercise adaptations and some of these adaptations (e.g. improved aerobic capacity and exercise-induced mitochondrial remodelling) offset age-related physiological decline. Exercise-induced mitochondrial remodelling is mediated by upstream signalling events that converge on downstream transcriptional co-factors and factors that orchestrate a co-ordinated nuclear and mitochondrial transcriptional response associated with mitochondrial remodelling. Recent translational human investigations have demonstrated similar exercise-induced mitochondrial signalling responses in older compared with younger skeletal muscle, regardless of training status. This is consistent with data indicating normative mitochondrial remodelling responses to long-term exercise training in the elderly. Thus, human ageing is not accompanied by diminished mitochondrial plasticity to acute and chronic exercise stimuli, at least for the signalling pathways measured to date. Exercise-induced increases in reactive oxygen and nitrogen species promote an acute redox-regulated stress response that manifests as increased heat shock protein and antioxidant enzyme content. In accordance with previous reports in rodents and mice, it appears that sedentary ageing is associated with a severely attenuated exercise-induced redox stress response that might be related to an absent redox signal. In this regard, regular exercise training affords some protection but does not completely override age-related defects. Despite some failed redox-regulated stress responses, it seems mitochondrial responses to exercise training are intact in skeletal muscle with age and this might underpin the protective effect of exercise training on age-related musculoskeletal decline. Whilst further investigation is required, recent data suggest that it is never too late to begin exercise training and that lifelong training provides protection against several age-related declines at both the molecular (e.g. reduced mitochondrial function) and whole-body level (e.g. aerobic capacity).

Development and validation of a questionnaire to measure the severity of functional limitations and reduction of sports ability in German-speaking patients with exercise-induced leg pain.

PubMed

Nauck, Tanja; Lohrer, Heinz; Padhiar, Nat; King, John B

2015-01-01

Currently, there is no generally agreed measure available to quantify a subject's perceived severity of exercise-induced leg pain symptoms. The aim of this study was to develop and validate a questionnaire that measures the severity of symptoms that impact on function and sports ability in patients with exercise-induced leg pain. The exercise-induced leg pain questionnaire for German-speaking patients (EILP-G) was developed in five steps: (1) initial item generation, (2) item reduction, (3) pretesting, (4) expert meeting and (5) validation. The resulting EILP-G was tested for reliability, validity and internal consistency in 20 patients with exercise-induced leg pain, 20 asymptomatic track and field athletes serving as a population at risk and 33 asymptomatic sport students. The patient group scored the EILP-G questionnaire significantly lower than both control groups (each p<0.001). Test-retest demonstrates an excellent reliability in all tested groups (Intraclass Correlation Coefficient, ICC=0.861-0.987). Concurrent validity of the EILP-G questionnaire showed a substantial agreement when correlated with the chronic exertional compartment syndrome classification system of Schepsis (r=-0.743; p<0.001). Internal consistency for the EILP-G questionnaire was 0.924. EILP-G questionnaire is a valid and reliable self-administered and disease-related outcome tool to measure the severity of symptoms that impact on function and sports ability in patients with exercise-induced leg pain. It can be recommended as a robust tool for measuring the subjectively perceived severity in German-speaking patients with exercise-induced leg pain. 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.

Application of cytoplasmic Ca2+ fluorescence imaging techniques to study the molecular mechanisms of exercise-induced fatigue eliminated by Chinese medicine ginseng extract

NASA Astrophysics Data System (ADS)

Liu, Yi; Zhao, Yanping; Zhang, Heming; Liu, Songhao

2009-11-01

The exercise-induced fatigue eliminated by Chinese medicine offers advantages including good efficiency and smaller side-effects, however, the exact mechanisms have not been classified. A lot of literatures indicated the cytosolic free Ca2+ concentrations of skeletal muscle cells increased significantly during exercise-induced fatigue. This study is aimed to establish a rat skeletal muscle cell model of exercise-induced fatigue. We applied cytoplasmic Ca2+ fluorescence imaging techniques to study the molecular mechanisms of exercise-induced fatigue eliminated by Chinese medicine ginseng extract. In our research, the muscle tissues from the newborn 3 days rats were taken out and digested into cells. The cells were randomly divided into the ginseng extract group and the control group. The cells from the two groups were cultured in the medium respectively added 2mg/ml ginseng extract and 2mg/ml D-hanks solution. After differentiating into myotubes, the two groups of cells treated with a fluorescent probe Fluo-3 AM were put on the confocal microscope and the fluorescence intensity of cells pre- and post- stimulation with dexamethasone were detected. It was found that cytoplasmic Ca2+ concentrations of the two groups of cells both increased post-stimulation, however, the increasing amplitude of fluorescence intensity of the ginseng extract group was significantly lower than that of the control group. In conclusion, stimulating the cells with dexamethasone is a kind of workable cell models of exercise-induced fatigue, and the molecular mechanisms of exercise-induced fatigue eliminated by ginseng extract may be connected to regulatating cytosolic free Ca2+ concentrations.

Improvement of Acetylcholine-Induced Vasodilation by Acute Exercise in Ovariectomized Hypertensive Rats.

PubMed

Cheng, Tsung-Lin; Lin, Yi-Yuan; Su, Chia-Ting; Hu, Chun-Che; Yang, Ai-Lun

2016-06-30

Postmenopause is associated with the development of cardiovascular disease, such as hypertension. However, limited information is available regarding effects of exercise on cardiovascular responses and its underlying mechanisms in the simultaneous postmenopausal and hypertensive status. We aimed to investigate whether acute exercise could enhance vasodilation mediated by acetylcholine (ACh) and sodium nitroprusside (SNP) in ovariectomized hypertensive rats. The fifteen-week-old female spontaneously hypertensive rats (SHR) were bilaterally ovariectomized, at the age of twenty-four weeks, and randomly divided into sedentary (SHR-O) and acute exercise (SHR-OE) groups. Age-matched WKY rats were used as the normotensive control group. The SHR-OE group ran on a motor-driven treadmill at a speed of 24 m/min for one hour in a moderate-intensity program. Following a single bout of exercise, rat aortas were isolated for the evaluation of the endothelium-dependent (ACh-induced) and endothelium-independent (SNP-induced) vasodilation by the organ bath system. Also, the serum levels of oxidative stress and antioxidant activities, including malondialdehyde (MDA), superoxide dismutase (SOD), and catalase, were measured after acute exercise among the three groups. We found that acute exercise significantly enhanced the ACh-induced vasodilation, but not the SNP-induced vasodilation, in ovariectomized hypertensive rats. This increased vasodilation was eliminated after the inhibition of nitric oxide synthase (NOS). Also, the activities of SOD and catalase were significantly increased after acute exercise, whereas the level of MDA was comparable among the three groups. These results indicated that acute exercise improved the endothelium-dependent vasodilating response to ACh through the NOS-related pathway in ovariectomized hypertensive rats, which might be associated with increased serum antioxidant activities.

Exercise-induced myocardial ischemia in patients with coronary artery disease: lack of evidence for platelet activation or fibrin formation in peripheral venous blood.

PubMed

Marcella, J J; Nichols, A B; Johnson, L L; Owen, J; Reison, D S; Kaplan, K L; Cannon, P J

1983-05-01

The hypothesis that exercise-induced myocardial ischemia is associated with abnormal platelet activation and fibrin formation or dissolution was tested in patients with coronary artery disease undergoing upright bicycle stress testing. In vivo platelet activation was assessed by radioimmunoassay of platelet factor 4, beta-thrombo-globulin and thromboxane B2. In vivo fibrin formation was assessed by radioimmunoassay of fibrinopeptide A, and fibrinolysis was assessed by radioimmunoassay of thrombin-increasable fibrinopeptide B which reflects plasmin cleavage of fibrin I. Peripheral venous concentrations of these substances were measured in 10 normal subjects and 13 patients with coronary artery disease at rest and during symptom-limited peak exercise. Platelet factor 4, beta-thromboglobulin and thromboxane B2 concentrations were correlated with rest and exercise catecholamine concentrations to determine if exercise-induced elevation of norepinephrine and epinephrine enhances platelet activation. Left ventricular end-diastolic and end-systolic volumes, ejection fraction and segmental wall motion were measured at rest and during peak exercise by first pass radionuclide angiography. All patients with coronary artery disease had documented exercise-induced myocardial ischemia manifested by angina pectoris, ischemic electrocardiographic changes, left ventricular segmental dyssynergy and a reduction in ejection fraction. Rest and peak exercise plasma concentrations were not significantly different for platelet factor 4, beta-thromboglobulin, thromboxane B2, fibrinopeptide A and thrombin-increasable fibrinopeptide B. Peripheral venous concentrations of norepinephrine and epinephrine increased significantly (p less than 0.001) in both groups of patients. The elevated catecholamine levels did not lead to detectable platelet activation. This study demonstrates that enhanced platelet activation, thromboxane release and fibrin formation or dissolution are not detectable in peripheral venous blood of patients with coronary disease during exercise-induced myocardial ischemia.

Exercise Training Mitigates Water Pipe Smoke Exposure-Induced Pulmonary Impairment via Inhibiting NF-κB and Activating Nrf2 Signalling Pathways

PubMed Central

Yuvaraju, Priya; Beegam, Sumaya; Ali, Badreldin H.

2018-01-01

Water pipe smoking is a tobacco smoking method commonly used in Eastern countries and is gaining popularity in Europe and North America, in particular among adolescents and young adults. Several clinical and experimental studies have reported that exposure to water pipe smoke (WPS) induces lung inflammation and impairment of pulmonary function. However, the mechanisms of such effects are not understood, as are data on the possible palliative effect of exercise training. The present study evaluated the effects of regular aerobic exercise training (treadmill: 5 days/week, 40 min/day) on subchronic exposure to WPS (30 minutes/day, 5 days/week for 2 months). C57BL/6 mice were exposed to air or WPS with or without exercise training. Airway resistance measured using forced oscillation technique was significantly and dose-dependently increased in the WPS-exposed group when compared with the air-exposed one. Exercise training significantly prevented the effect of WPS on airway resistance. Histologically, the lungs of WPS-exposed mice had focal moderate interstitial inflammatory cell infiltration consisting of neutrophil polymorphs, plasma cells, and lymphocytes. There was a mild increase in intra-alveolar macrophages and a focal damage to alveolar septae in some foci. Exercise training significantly alleviated these effects and also decreased the WPS-induced increase of tumor necrosis factor α and interleukin 6 concentrations and attenuated the increase of 8-isoprostane in lung homogenates. Likewise, the lung DNA damage induced by WPS was significantly inhibited by exercise training. Moreover, exercise training inhibited nuclear factor kappa-B (NF-κB) expression induced by WPS and increased that of nuclear factor erythroid 2-related factor 2 (Nrf2). Our findings suggest that exercise training significantly mitigated WPS-induced increase in airway resistance, inflammation, oxidative stress, and DNA damage via mechanisms that include inhibiting NF-κB and activating Nrf2 signalling pathways. PMID:29692875

Fiber type-specific afferent nerve activity induced by transient contractions of rat bladder smooth muscle in pathological states

PubMed Central

Kuga, Nahoko; Tanioka, Asao; Hagihara, Koichiro; Kawai, Tomoyuki

2017-01-01

Bladder smooth muscle shows spontaneous phasic contractions, which undergo a variety of abnormal changes depending on pathological conditions. How abnormal contractions affect the activity of bladder afferent nerves remains to be fully tested. In this study, we examined the relationship between transient increases in bladder pressure, representing transient contraction of bladder smooth muscle, and spiking patterns of bladder afferent fibers of the L6 dorsal root, in rat pathological models. All recordings were performed at a bladder pressure of approximately 10 cmH2O by maintaining the degree of bladder filling. In the cyclophosphamide-induced model, both Aδ and C fibers showed increased sensitivity to transient bladder pressure increases. In the prostaglandin E2-induced model, Aδ fibers, but not C fibers, specifically showed overexcitation that was time-locked with transient bladder pressure increases. These fiber type-specific changes in nerve spike patterns may underlie the symptoms of urinary bladder diseases. PMID:29267380

Protective Effects of Enriched Environment Against Transient Cerebral Ischemia-Induced Impairment of Passive Avoidance Memory and Long-Term Potentiation in Rats

PubMed Central

Ahmadalipour, Ali; Sadeghzadeh, Jafar; Samaei, Seyed Afshin; Rashidy-Pour, Ali

2017-01-01

Introduction: Enriched Environment (EE), a complex novel environment, has been demonstrated to improve synaptic plasticity in both injured and intact animals. The present study investigated the capacity of an early environmental intervention to normalize the impairment of passive avoidance memory and Long-Term Potentiation (LTP) induced by transient bilateral common carotid artery occlusion (2-vessel occlusion, 2VO) in rats. Methods: After weaning, young Wistar rats (22 days old) were housed in EE or Standard Environment (SE) for 40 days. Transient (30-min) incomplete forebrain ischemia was induced 4 days before the passive avoidance memory test and LTP induction. Results: The transient forebrain ischemia led to impairment of passive avoidance memory and LTP induction in the Perforant Path-Dentate Gyrus (PP-DG) synapses. Interestingly, housing and growing in EE prior to 2VO was found to significantly reverse 2VO-induced cognitive and LTP impairments. Conclusion: Our results suggest that early housing and growing in EE exhibits therapeutic potential to normalize cognitive and LTP abnormalities induced by 2VO ischemic model in rats.

Exercise-induced ischemia initiates the second window of protection in humans independent of collateral recruitment.

PubMed

Lambiase, Pier D; Edwards, Richard J; Cusack, Michael R; Bucknall, Clifford A; Redwood, Simon R; Marber, Michael S

2003-04-02

This study was designed to examine if exercise-induced ischemia initiated late preconditioning in humans that becomes manifest during subsequent exercise and serial balloon occlusion of the left anterior descending coronary artery (LAD). The existence of late preconditioning in humans is controversial. We therefore compared myocardial responses to exercise-induced and intracoronary balloon inflation-induced ischemia in two groups of patients subjected to different temporal patterns of ischemia. Thirty patients with stable angina secondary to single-vessel LAD disease underwent percutaneous coronary intervention (PCI) after two separate exercise tolerance test (ETT) protocols designed to investigate isolated early preconditioning (IEP) alone or the second window of protection (SWOP). The IEP subjects underwent three sequential ETTs at least two weeks before PCI. The SWOP subjects underwent five sequential ETTs commencing 24 h before PCI. During PCI there was no significant difference in intracoronary pressure-derived collateral flow index (CFI) between groups (IEP = 0.15 +/- 0.13, SWOP = 0.19 +/- 0.15). In SWOP patients, compared with the initial ETT, the ETT performed 24 h later had a 40% (p < 0.001) increase in time to 0.1-mV ST depression and a 60% (p < 0.05) decrease in ventricular ectopic frequency. During the first balloon inflation, peak ST elevation was reduced by 49% (p < 0.05) in the SWOP versus the IEP group, and the dependence on CFI observed in the IEP group was abolished (analysis of covariance, p < 0.05). The significant attenuation of ST elevation (47%, p < 0.005) seen at the time of the second inflation in the IEP patients was not seen in the SWOP patients. Exercise-induced ischemia triggers late preconditioning in humans, which becomes manifest during exercise and PCI. This is the first evidence that ischemia induced by coronary occlusion is attenuated in humans by a late preconditioning effect induced by exercise.

Comparison of Single-Event Transients Induced in an Operational Amplifier (LM124) by Pulsed Laser Light and a Broad Beam of Heavy Ions

NASA Technical Reports Server (NTRS)

Buchner, Steve; McMorrow, Dale; Poivey, Christian; Howard, James, Jr.; Pease, Rom; Savage, Mark; Boulghassoul, Younis; Massengill, Lloyd

2003-01-01

A comparison of transients from heavy-ion and pulsed-laser testing shows good agreement for many different voltage configurations. The agreement is illustrated by comparing directly individual transients and plots of transient amplitude versus width.

Long-term exercise training prevents mammary tumorigenesis-induced muscle wasting in rats through the regulation of TWEAK signalling.

PubMed

Padrão, A I; Figueira, A C C; Faustino-Rocha, A I; Gama, A; Loureiro, M M; Neuparth, M J; Moreira-Gonçalves, D; Vitorino, R; Amado, F; Santos, L L; Oliveira, P A; Duarte, J A; Ferreira, R

2017-04-01

Exercise training has been suggested as a non-pharmacological approach to prevent skeletal muscle wasting and improve muscle function in cancer cachexia. However, little is known about the molecular mechanisms underlying such beneficial effect. In this study, we aimed to, firstly, examine the contribution of TWEAK signalling to cancer-induced skeletal muscle wasting and, secondly, evaluate whether long-term exercise alters TWEAK signalling and prevents muscle wasting. Female Sprague-Dawley rats were randomly assigned to control and exercise groups. Fifteen animals from each group were exposed to N-Methyl-N-nitrosourea carcinogen. Animals in exercise groups were submitted to moderate treadmill exercise for 35 weeks. After the experimental period, animals were killed and gastrocnemius muscles were harvested for morphological and biochemical analysis. We verified that exercise training prevented tumour-induced TWEAK/NF-κB signalling in skeletal muscle with a beneficial impact in fibre cross-sectional area and metabolism. Indeed, 35 weeks of exercise training promoted the upregulation of PGC-1α and oxidative phosphorylation complexes. This exercise-induced muscle remodelling in tumour-bearing animals was associated with less malignant mammary lesions. Data support the benefits of an active lifestyle for the prevention of muscle wasting secondary to breast cancer, highlighting TWEAK/NF- κB signalling as a potential therapeutic target for the preservation of muscle mass. © 2016 Scandinavian Physiological Society. Published by John Wiley & Sons Ltd.

Suppressed heat shock protein response in the kidney of exercise-trained diabetic rats.

PubMed

Lappalainen, J; Oksala, N K J; Laaksonen, D E; Khanna, S; Kokkola, T; Kaarniranta, K; Sen, C K; Atalay, M

2018-07-01

Impaired expression of heat shock proteins (HSPs) and increased oxidative stress may contribute to the pathophysiology of diabetes by disrupted tissue protection. Acute exercise induces oxidative stress, whereas exercise training up-regulates endogenous antioxidant defenses and HSP expression. Although diabetic nephropathy is a major contributor to diabetic morbidity, information regarding the effect of HSPs on kidney protection is limited. This study evaluated the effects of eight-week exercise training on kidney HSP expression and markers of oxidative stress at rest and after acute exercise in rats with or without streptozotocin-induced diabetes. Induction of diabetes increased DNA-binding activity of heat shock factor-1, but decreased the expression of HSP72, HSP60, and HSP90. The inflammatory markers IL-6 and TNF-alpha were increased in the kidney tissue of diabetic animals. Both exercise training and acute exercise increased HSP72 and HSP90 protein levels only in non-diabetic rats. On the other hand, exercise training appeared to reverse the diabetes-induced histological changes together with decreased expression of TGF-beta as a key inducer of glomerulosclerosis, and decreased levels of IL-6 and TNF-alpha. Notably, HSP72 and TGF-beta were negatively correlated. In conclusion, impaired HSP defense seems to contribute to kidney injury vulnerability in diabetes and exercise training does not up-regulate kidney HSP expression despite the improvements in histopathological and inflammatory markers. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Regulation of angiopoietin‐like protein 4 production during and after exercise

PubMed Central

Norheim, Frode; Hjorth, Marit; Langleite, Torgrim M.; Lee, Sindre; Holen, Torgeir; Bindesbøll, Christian; Stadheim, Hans K.; Gulseth, Hanne L.; Birkeland, Kåre I.; Kielland, Anders; Jensen, Jørgen; Dalen, Knut T.; Drevon, Christian A.

2014-01-01

Abstract Angiopoietin‐like protein 4 (ANGPTL4) may regulate lipoprotein lipase‐dependent plasma clearance of triacylglycerol from skeletal muscle during exercise. The aim of this study was to examine the importance of muscle in regulating ANGPTL4 in response to exercise. We sampled muscle biopsies and serum before, immediately after, and 2 h after 45 min of ergometer cycling. Sampling was done before and after a 12‐week training intervention in controls and dysglycemic subjects. Moreover, fat biopsies were taken before and after the training intervention. The regulation of ANGPTL4 was also investigated in several tissues of exercising mice, and in cultured myotubes. ANGPTL4 levels in serum and expression in muscle were highest 2 h after exercise in both groups. Whereas ANGPTL4 was higher in muscle of exercising controls as compared to dysglycemic subjects, the opposite was observed in serum. In exercising mice, Angptl4 mRNA showed both higher basal expression and induction in liver compared to muscle. Angptl4 mRNA was much higher in adipose tissue than muscle and was also induced by exercise. We observed two mRNA isoforms of ANGPTL4 in muscle and fat in humans. Both were induced by exercise in muscle; one isoform was expressed 5‐ to 10‐fold higher than the other. Studies in mice and cultured myotubes showed that both fatty acids and cortisol have the potential to increase ANGPTL4 expression in muscle during exercise. In conclusion, ANGPTL4 is markedly induced in muscle in response to exercise. However, liver and adipose tissue may contribute more than muscle to the exercise‐induced increase in circulating ANGPTL4. PMID:25138789

Exploring the Mechanisms of Exercise-Induced Hypoalgesia Using Somatosensory and Laser Evoked Potentials.

PubMed

Jones, Matthew D; Taylor, Janet L; Booth, John; Barry, Benjamin K

2016-01-01

Exercise-induced hypoalgesia is well described, but the underlying mechanisms are unclear. The aim of this study was to examine the effect of exercise on somatosensory evoked potentials, laser evoked potentials, pressure pain thresholds and heat pain thresholds. These were recorded before and after 3-min of isometric elbow flexion exercise at 40% of the participant's maximal voluntary force, or an equivalent period of rest. Exercise-induced hypoalgesia was confirmed in two experiments (Experiment 1-SEPs; Experiment 2-LEPs) by increased pressure pain thresholds at biceps brachii (24.3 and 20.6% increase in Experiment 1 and 2, respectively; both d > 0.84 and p < 0.001) and first dorsal interosseous (18.8 and 21.5% increase in Experiment 1 and 2, respectively; both d > 0.57 and p < 0.001). In contrast, heat pain thresholds were not significantly different after exercise (forearm: 10.8% increase, d = 0.35, p = 0.10; hand: 3.6% increase, d = 0.06, p = 0.74). Contrasting effects of exercise on the amplitude of laser evoked potentials (14.6% decrease, d = -0.42, p = 0.004) and somatosensory evoked potentials (10.9% increase, d = -0.02, p = 1) were also observed, while an equivalent period of rest showed similar habituation (laser evoked potential: 7.3% decrease, d = -0.25, p = 0.14; somatosensory evoked potential: 20.7% decrease, d = -0.32, p = 0.006). The differential response of pressure pain thresholds and heat pain thresholds to exercise is consistent with relative insensitivity of thermal nociception to the acute hypoalgesic effects of exercise. Conflicting effects of exercise on somatosensory evoked potentials and laser evoked potentials were observed. This may reflect non-nociceptive contributions to the somatosensory evoked potential, but could also indicate that peripheral nociceptors contribute to exercise-induced hypoalgesia.

Cross refractoriness between sodium metabisulphite and exercise induced asthma.

PubMed Central

Pavord, I.; Lazarowicz, H.; Inchley, D.; Baldwin, D.; Knox, A.; Tattersfield, A.

1994-01-01

BACKGROUND--Exercise and inhaled sodium metabisulphite are thought to cause bronchoconstriction in asthma through different mechanisms. The response to both stimuli becomes refractory with repeat challenge. The mechanism of refractoriness is unclear, although depletion of mast cell derived mediators or neurotransmitters has been suggested. Recent studies suggest a common mechanism involving release of inhibitory prostaglandins. If this is true, exercise and sodium metabisulphite induced bronchoconstriction should show cross refractoriness. METHODS--Thirteen subjects with mild asthma and previously established exercise and sodium metabisulphite induced bronchoconstriction performed two sodium metabisulphite challenges (giving a single dose previously shown to cause a 20% fall in FEV1) on one study day, and two exercise tests on another. The second challenge proceeded after recovery (FEV1 > 95% baseline) from the first. Subjects then attended on two further occasions when an exercise test was performed after sodium metabisulphite and a sodium metabisulphite challenge after exercise. RESULTS--When expressed as the percentage reduction in the area under the change in percentage FEV1 curve over 20 minutes (AUC) the response to exercise was reduced by a mean 62.3% (95% CI 46.5% to 78.1%) following a first exercise challenge, and by 50.7% (95% CI 27.8% to 73.6%) following a sodium metabisulphite challenge. The response to a sodium metabisulphite challenge was reduced by a mean of 80.2% (95% CI 68.9% to 91.5%) when it followed a sodium metabisulphite challenge, and by 37.3% (95% CI 15.1% to 59.5%) following an exercise challenge. CONCLUSION--This study shows some cross refractoriness between exercise and sodium metabisulphite induced bronchoconstriction, in keeping with a partially shared mechanism of refractoriness. PMID:8202881

BDNF Expression in Perirhinal Cortex is Associated with Exercise-Induced Improvement in Object Recognition Memory

PubMed Central

Hopkins, Michael E.; Bucci, David J.

2010-01-01

Physical exercise induces widespread neurobiological adaptations and improves learning and memory. Most research in this field has focused on hippocampus-based spatial tasks and changes in brain-derived neurotrophic factor (BDNF) as a putative substrate underlying exercise-induced cognitive improvements. Chronic exercise can also be anxiolytic and causes adaptive changes in stress reactivity. The present study employed a perirhinal cortex-dependent object recognition task as well as the elevated plus maze to directly test for interactions between the cognitive and anxiolytic effects of exercise in male Long Evans rats. Hippocampal and perirhinal cortex tissue was collected to determine whether the relationship between BDNF and cognitive performance extends to this non-spatial and non-hippocampal-dependent task. We also examined whether the cognitive improvements persisted once the exercise regimen was terminated. Our data indicate that 4 weeks of voluntary exercise every-other-day improved object recognition memory. Importantly, BDNF expression in the perirhinal cortex of exercising rats was strongly correlated with object recognition memory. Exercise also decreased anxiety-like behavior, however there was no evidence to support a relationship between anxiety-like behavior and performance on the novel object recognition task. There was a trend for a negative relationship between anxiety-like behavior and hippocampal BDNF. Neither the cognitive improvements nor the relationship between cognitive function and perirhinal BDNF levels persisted after 2 weeks of inactivity. These are the first data demonstrating that region-specific changes in BDNF protein levels are correlated with exercise-induced improvements in non-spatial memory, mediated by structures outside the hippocampus and are consistent with the theory that, with regard to object recognition, the anxiolytic and cognitive effects of exercise may be mediated through separable mechanisms. PMID:20601027

Increases of Catalase and Glutathione Peroxidase Expressions by Lacosamide Pretreatment Contributes to Neuroprotection Against Experimentally Induced Transient Cerebral Ischemia.

PubMed

Choi, Hyun Young; Park, Joon Ha; Chen, Bai Hui; Shin, Bich Na; Lee, Yun Lyul; Kim, In Hye; Cho, Jeong-Hwi; Lee, Tae-Kyeong; Lee, Jae-Chul; Won, Moo-Ho; Ahn, Ji Hyeon; Tae, Hyun-Jin; Yan, Bing Chun; Hwang, In Koo; Cho, Jun Hwi; Kim, Young-Myeong; Kim, Sung Koo

2016-09-01

Lacosamide is a new antiepileptic drug which is widely used to treat partial-onset seizures. In this study, we examined the neuroprotective effect of lacosamide against transient ischemic damage and expressions of antioxidant enzymes such as Zn-superoxide dismutase (SOD1), Mn-superoxide dismutase (SOD2), catalase (CAT) and glutathione peroxidase (GPX) in the hippocampal cornu ammonis 1 (CA1) region following 5 min of transient global cerebral ischemia in gerbils. We found that pre-treatment with 25 mg/kg lacosamide protected CA1 pyramidal neurons from transient global cerebral ischemic insult using hematoxylin-eosin staining and neuronal nuclear antigen immunohistochemistry. Transient ischemia dramatically changed expressions of SOD1, SOD2 and GPX, not CAT, in the CA1 pyramidal neurons. Lacosamide pre-treatment increased expressions of CAT and GPX, not SOD1 and 2, in the CA1 pyramidal neurons compared with controls, and their expressions induced by lacosamide pre-treatment were maintained after transient cerebral ischemia. In brief, pre-treatment with lacosamide protected hippocampal CA1 pyramidal neurons from ischemic damage induced by transient global cerebral ischemia, and the lacosamide-mediated neuroprotection may be closely related to increases of CAT and GPX expressions by lacosamide pre-treatment.

Effects of a Strength Training Session After an Exercise Inducing Muscle Damage on Recovery Kinetics.

PubMed

Abaïdia, Abd-Elbasset; Delecroix, Barthélémy; Leduc, Cédric; Lamblin, Julien; McCall, Alan; Baquet, Georges; Dupont, Grégory

2017-01-01

Abaïdia, A-E, Delecroix, B, Leduc, C, Lamblin, J, McCall, A, Baquet, G, and Dupont, G. Effects of a strength training session after an exercise inducing muscle damage on recovery kinetics. J Strength Cond Res 31(1): 115-125, 2017-The purpose of this study was to investigate the effects of an upper-limb strength training session the day after an exercise inducing muscle damage on recovery of performance. In a randomized crossover design, subjects performed the day after the exercise, on 2 separate occasions (passive vs. active recovery conditions) a single-leg exercise (dominant in one condition and nondominant in the other condition) consisting of 5 sets of 15 eccentric contractions of the knee flexors. Active recovery consisted of performing an upper-body strength training session the day after the exercise. Creatine kinase, hamstring strength, and muscle soreness were assessed immediately and 20, 24, and 48 hours after exercise-induced muscle damage. The upper-body strength session, after muscle-damaging exercise accelerated the recovery of slow concentric force (effect size = 0.65; 90% confidence interval = -0.06 to 1.32), but did not affect the recovery kinetics for the other outcomes. The addition of an upper-body strength training session the day after muscle-damaging activity does not negatively affect the recovery kinetics. Upper-body strength training may be programmed the day after a competition.

The Exercise-Induced Irisin Is Associated with Improved Levels of Glucose Homeostasis Markers in Pregnant Women Participating in 8-Week Prenatal Group Fitness Program: A Pilot Study.

PubMed

Szumilewicz, Anna; Worska, Aneta; Piernicka, Magdalena; Kuchta, Agnieszka; Kortas, Jakub; Jastrzębski, Zbigniew; Radzimiński, Łukasz; Jaworska, Joanna; Micielska, Katarzyna; Ziemann, Ewa

2017-01-01

Both exercise and pregnancy influence serum irisin concentration. To determine how the interaction of pregnancy and exercise affects irisin level and whether various patterns of exercise adherence had different effect on irisin concentration. It was a one-group pretest-posttest study among 9 Caucasian nulliparous healthy women in normal pregnancy (age 23 ± 3 years, 21 ± 2 weeks of gestation; mean ± SD) who participated in 8-week group fitness program. Before and after exercise intervention, we determined serum concentrations of irisin and selected parameters of lipid profile and glucose homeostasis markers. In active women, irisin slightly decreased with the development of pregnancy. After 8 weeks of exercising, irisin correlated negatively with fasting glucose ( R = -0.922; p = 0.001), glycated hemoglobin ( R = -0.784; p = 0.012), and insulin concentrations ( R = -0.845; p = 0.004). In women exercising below recommended level, we observed a significant drop in irisin concentration, whereas in women exercising at least three times a week this myokine slightly increased (31% difference; 90% confidence limits ±28; a large, clear effect). Irisin stimulated by prenatal exercise may improve glucose homeostasis markers in healthy women and compensate for metabolic changes induced by pregnancy. Moreover, the frequency of exercise may regulate the changes in exercise-induced irisin concentration.

Inorganic Nitrate Mimics Exercise-Stimulated Muscular Fiber-Type Switching and Myokine and γ-Aminobutyric Acid Release.

PubMed

Roberts, Lee D; Ashmore, Tom; McNally, Ben D; Murfitt, Steven A; Fernandez, Bernadette O; Feelisch, Martin; Lindsay, Ross; Siervo, Mario; Williams, Elizabeth A; Murray, Andrew J; Griffin, Julian L

2017-03-01

Exercise is an effective intervention for the prevention and treatment of type 2 diabetes. Skeletal muscle combines multiple signals that contribute to the beneficial effects of exercise on cardiometabolic health. Inorganic nitrate increases exercise efficiency, tolerance, and performance. The transcriptional regulator peroxisome proliferator-activated receptor γ coactivator 1α (PGC1α) coordinates the exercise-stimulated skeletal muscle fiber-type switch from glycolytic fast-twitch (type IIb) to oxidative slow-twitch (type I) and intermediate (type IIa) fibers, an effect reversed in insulin resistance and diabetes. We found that nitrate induces PGC1α expression and a switch toward type I and IIa fibers in rat muscle and myotubes in vitro. Nitrate induces the release of exercise/PGC1α-dependent myokine FNDC5/irisin and β-aminoisobutyric acid from myotubes and muscle in rats and humans. Both exercise and nitrate stimulated PGC1α-mediated γ-aminobutyric acid (GABA) secretion from muscle. Circulating GABA concentrations were increased in exercising mice and nitrate-treated rats and humans; thus, GABA may function as an exercise/PGC1α-mediated myokine-like small molecule. Moreover, nitrate increased circulating growth hormone levels in humans and rodents. Nitrate induces physiological responses that mimic exercise training and may underlie the beneficial effects of this metabolite on exercise and cardiometabolic health. © 2017 by the American Diabetes Association.

Conduit Artery Diameter During Exercise Is Enhanced After Local, but Not Remote, Ischemic Preconditioning

PubMed Central

Cocking, Scott; Cable, N. T.; Wilson, Mathew G.; Green, Daniel J.; Thijssen, Dick H. J.; Jones, Helen

2018-01-01

Introduction: The ability of ischemic preconditioning (IPC) to enhance exercise capacity may be mediated through altering exercise-induced blood flow and/or vascular function. This study investigated the hypothesis that (local) IPC enhances exercise-induced blood flow responses and prevents decreases in vascular function following exercise. Methods: Eighteen healthy, recreationally trained, male participants (mean ±SD: age 32 ± 8 years; BMI 24.2 ± 2.3; blood pressure 122 ± 10/72 ± 8 mmHg; resting HR 58 ± 9 beats min-1) received IPC (220 mmHg; 4 × 5-min bilateral arms), REMOTE IPC (220 mmHg; 4 × 5-min bilateral legs), or SHAM (20 mmHg; 4 × 5-min bilateral arms) in a counterbalanced order prior to 30-min of submaximal (25% maximal voluntary contraction) unilateral rhythmic handgrip exercise. Brachial artery diameter and blood flow were assessed every 5-min throughout the 30-min submaximal exercise using high resolution ultrasonography. Pre- and post-exercise vascular function was measured using flow-mediated dilation (FMD). Results: IPC resulted in enlarged brachial artery diameter during exercise [0.016 cm (0.003–0.03 cm), P = 0.015] compared to REMOTE IPC, but blood flow during exercise was similar between conditions (P > 0.05). Blood flow (l/min) increased throughout exercise (time: P < 0.005), but there was no main effect of condition (P = 0.29) or condition ∗ time interaction (P = 0.83). Post-exercise FMD was similar between conditions (P > 0.05). Conclusion: Our data show that local (but not remote) IPC, performed as a strategy prior to exercise, enhanced exercise-induced conduit artery diameter dilation, but these changes do not translate into increased blood flow during exercise nor impact post-exercise vascular function. PMID:29740345

Wheezing or Breezing through Exercise-Induced Asthma.

ERIC Educational Resources Information Center

McCarthy, Paul

1989-01-01

Several physicians discuss the tests they use to diagnose exercise-induced asthma (EIA), the medications they typically prescribe and why, and the importance of properly educating athletes about EIA. (JD)

Special Medical Problems of Athletes.

ERIC Educational Resources Information Center

Couch, Joan M.

1987-01-01

This article addresses the situations in which athletes with special needs and considerations participate in sports. The health problems discussed are diabetes mellitus, exercise-induced asthma, exercise-induced anaphylaxis, and epilepsy. (MT)

Effects of treadmill exercise on the LiCl-induced conditioned taste aversion in rats.

PubMed

Tsuboi, Hisanori; Hirai, Yoshiyuki; Maezawa, Hitoshi; Notani, Kenji; Inoue, Nobuo; Funahashi, Makoto

2015-01-01

Studies have shown that exercise can enhance learning and memory. Conditioned taste aversion (CTA) is an avoidance behavior induced by associative memory of the taste sensation for something pleasant or neutral with a negative visceral reaction caused by the coincident action of a toxic substance that is tasteless or administered systemically. We sought to measure the effects of treadmill exercise on CTA in rats by investigating the effects of exercise on acquisition, extinction and spontaneous recovery of CTA. We made two groups of rats: an exercise group that ran on a treadmill, and a control group that did not have structured exercise periods. To condition rats to disfavor a sweet taste, consumption of a 0.1% saccharin solution in place of drinking water was paired with 0.15M LiCl (2% body weight, i.p.) to induce visceral discomfort. We measured changes of saccharin consumption during acquisition and extinction of CTA. The exercise and no-exercise groups both acquired CTA to similar levels and showed maximum extinction of CTA around 6 days after acquisition. This result indicates that exercise affects neither acquisition nor extinction of CTA. However, in testing for preservation of CTA after much longer extinction periods that included exercise or not during the intervening period, exercising animals showed a significantly lower saccharin intake, irrespective of having exercised or not during the conditioning phase of the trial. This result suggests that exercise may help to preserve aversive memory (taste aversion in this example) as evidence by the significant spontaneous recovery of aversion in exercising animals. Copyright © 2014 Elsevier Inc. All rights reserved.

Wasp venom blocks central cholinergic synapses to induce transient paralysis in cockroach prey.

PubMed

Haspel, G; Libersat, F

2003-03-01

The parasitoid wasp Ampulex compressa induces a set of unique behavioral effects upon stinging its prey, the cockroach. It stings into the first thoracic segment inducing 2 to 3 min of transient flaccid paralysis of the front legs. This facilitates a second sting in the cockroach's head that induces 30 min of excessive grooming followed by a 2 to 5-week long lethargic state. In the present study, we examine the immediate effect of the first sting, which is a transient paralysis of the front legs. Using radiolabeled wasps, we demonstrate that the wasp injects its venom directly into the cockroach's first thoracic ganglion. The artificial injection of milked venom into a thoracic ganglion abolishes spontaneous and evoked responses of the motoneurons associated with leg movements. To investigate the physiological mechanism of action of the venom, we injected venom into the last abdominal ganglion of the cockroach, which houses a well-characterized cholinergic synapse. Injected venom abolishes both sensory-evoked and agonist-evoked postsynaptic potentials recorded in the postsynaptic neuron for 2 to 3 min without affecting action potential propagation. Thus, the venom blocking effect has a postsynaptic component that follows the same time course as the transient paralysis induced by the thoracic sting. Finally, injection of a nicotinic antagonist in the front thoracic ganglion induces paralysis of the front legs. We conclude that the transient paralytic effect of the thoracic sting can be mainly accounted for by the presence of a venom active component that induces a postsynaptic block of central cholinergic synaptic transmission. Copyright 2003 Wiley Periodicals, Inc. J Neurobiol 54: 628-637, 2003

Effect of antioxidant supplementation on exercise-induced cardiac troponin release in cyclists: a randomized trial.

PubMed

Klinkenberg, Lieke J J; Res, Peter T; Haenen, Guido R; Bast, Aalt; van Loon, Luc J C; van Dieijen-Visser, Marja P; Meex, Steven J R

2013-01-01

Cardiac troponin is the biochemical gold standard to diagnose acute myocardial infarction. Interestingly however, elevated cardiac troponin concentrations are also frequently observed during and after endurance-type exercise. Oxidative stress associated with prolonged exercise has been proposed to contribute to cardiac troponin release. Therefore, the aim of this study was to assess the effect of 4 week astaxanthin supplementation (a potent cartenoid antioxidant) on antioxidant capacity and exercise-induced cardiac troponin release in cyclists. Thirty-two well-trained male cyclists (age 25±5, weight 73±7 kg, maximum O2 uptake 60±5 mL·kg(-1)·min(-1), Wmax 5.4±0.5 W·kg(-1); mean ± SD) were repeatedly subjected to a laboratory based standardized exercise protocol before and after 4 weeks of astaxanthin (20 mg/day), or placebo supplementation in a double-blind randomized manner. Blood samples were obtained at baseline, at 60 min of cycling and immediately post-exercise (≈ 120 min). The pre-supplementation cycling trial induced a significant rise of median cardiac troponin T concentrations from 3.2 (IQR 3.0-4.2) to 4.7 ng/L (IQR 3.7-6.7), immediately post-exercise (p<0.001). Four weeks of astaxanthin supplementation significantly increased mean basal plasma astaxanthin concentrations from non-detectable values to 175±86 µg·kg(-1). However, daily astaxanthin supplementation had no effect on exercise-induced cardiac troponin T release (p = 0.24), as measured by the incremental area under the curve. Furthermore, the elevation in basal plasma astaxanthin concentrations was not reflected in changes in antioxidant capacity markers (trolox equivalent antioxidant capacity, uric acid, and malondialdehyde). Markers of inflammation (high-sensitivity C-reactive protein) and exercise-induced skeletal muscle damage (creatine kinase) were equally unaffected by astaxanthin supplementation. Despite substantial increases in plasma astaxanthin concentrations, astaxanthin supplementation did not improve antioxidant capacity in well-trained cyclists. Accordingly, exercise-induced cardiac troponin T concentrations were not affected by astaxanthin supplementation. ClinicalTrials.gov NCT01241877.

Relationship between exercise pressure gradient and haemodynamic progression of aortic stenosis.

PubMed

Ringle, Anne; Levy, Franck; Ennezat, Pierre-Vladimir; Le Goffic, Caroline; Castel, Anne-Laure; Delelis, François; Menet, Aymeric; Malaquin, Dorothée; Graux, Pierre; Vincentelli, André; Tribouilloy, Christophe; Maréchaux, Sylvestre

We hypothesized that large exercise-induced increases in aortic mean pressure gradient can predict haemodynamic progression during follow-up in asymptomatic patients with aortic stenosis. We retrospectively identified patients with asymptomatic moderate or severe aortic stenosis (aortic valve area<1.5cm 2 or<1cm 2 ) and normal ejection fraction, who underwent an exercise stress echocardiography at baseline with a normal exercise test and a resting echocardiography during follow-up. The relationship between exercise-induced increase in aortic mean pressure gradient and annualised changes in resting mean pressure gradient during follow-up was investigated. Fifty-five patients (mean age 66±15 years; 45% severe aortic stenosis) were included. Aortic mean pressure gradient significantly increased from rest to peak exercise (P<0.001). During a median follow-up of 1.6 [1.1-3.2] years, resting mean pressure gradient increased from 35±13mmHg to 48±16mmHg, P<0.0001. Median annualised change in resting mean pressure gradient during follow-up was 5 [2-11] mmHg. Exercise-induced increase in aortic mean pressure gradient did correlate with annualised changes in mean pressure gradient during follow-up (r=0.35, P=0.01). Hemodynamic progression of aortic stenosis was faster in patients with large exercise-induced increase in aortic mean pressure gradient (≥20mmHg) as compared to those with exercise-induced increase in aortic mean pressure gradient<20mmHg (median annualised increase in mean pressure gradient 19 [6-28] vs. 4 [2-10] mmHg/y respectively, P=0.002). Similar results were found in the subgroup of 30 patients with moderate aortic stenosis. Large exercise-induced increases in aortic mean pressure gradient correlate with haemodynamic progression of stenosis during follow-up in patients with asymptomatic aortic stenosis. Further studies are needed to fully establish the role of ESE in the decision-making process in comparison to other prognostic markers in asymptomatic patients with aortic stenosis. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Acute exercise induces biphasic increase in respiratory mRNA in skeletal muscle

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ikeda, Shin-ichi; Kizaki, Takako; Haga, Shukoh

2008-04-04

Peroxisome proliferator-activated receptor {gamma} coactivator-1{alpha} (PGC-1{alpha}) promotes the expression of oxidative enzymes in skeletal muscle. We hypothesized that activation of the p38 MAPK (mitogen-activated protein kinase) in response to exercise was associated with exercise-induced PGC-1{alpha} and respiratory enzymes expression and aimed to demonstrate this under the physiological level. We subjected mice to a single bout of treadmill running and found that the exercise induced a biphasic increase in the expression of respiratory enzymes mRNA. The second phase of the increase was accompanied by an increase in PGC-1{alpha} protein, but the other was not. Administration of SB203580 (SB), an inhibitor ofmore » p38 MAPK, suppressed the increase in PGC-1{alpha} expression and respiratory enzymes mRNA in both phases. These data suggest that p38 MAPK is associated with the exercise-induced expression of PGC-1{alpha} and biphasic increase in respiratory enzyme mRNAs in mouse skeletal muscle under physiological conditions.« less

Chronic Swimming Exercise Ameliorates Low-Soybean-Oil Diet-Induced Spatial Memory Impairment by Enhancing BDNF-Mediated Synaptic Potentiation in Developing Spontaneously Hypertensive Rats.

PubMed

Cheng, Mei; Cong, Jiyan; Wu, Yulong; Xie, Jiacun; Wang, Siyuan; Zhao, Yue; Zang, Xiaoying

2018-05-01

Exercise and low-fat diets are common lifestyle modifications used for the treatment of hypertension besides drug therapy. However, unrestrained low-fat diets may result in deficiencies of low-unsaturated fatty acids and carry contingent risks of delaying neurodevelopment. While aerobic exercise shows positive neuroprotective effects, it is still unclear whether exercise could alleviate the impairment of neurodevelopment that may be induced by certain low-fat diets. In this research, developing spontaneously hypertensive rats (SHR) were treated with chronic swimming exercise and/or a low-soybean-oil diet for 6 weeks. We found that performance in the Morris water maze was reduced and long-term potentiation in the hippocampus was suppressed by the diet, while a combination treatment of exercise and diet alleviated the impairment induced by the specific low-fat diet. Moreover, the combination treatment effectively increased the expression of brain-derived neurotrophic factor (BDNF) and N-methyl-D-aspartic acid receptor (NMDAR), which were both down-regulated by the low-soybean-oil diet in the hippocampus of developing SHR. These findings suggest that chronic swimming exercise can ameliorate the low-soybean-oil diet-induced learning and memory impairment in developing SHR through the up-regulation of BDNF and NMDAR expression.

Voluntary exercise prevents colonic inflammation in high-fat diet-induced obese mice by up-regulating PPAR-γ activity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Wei-Xin, E-mail: weixinliu@yahoo.com; Wang, Ting; Zhou, Feng

Obesity is associated with increased colonic inflammation, which elevates the risk of colon cancer. Although exercise exerts anti-inflammatory actions in multiple chronic diseases associated with inflammation, it is unknown whether this strategy prevents colonic inflammation in obesity. We hypothesized that voluntary exercise would suppress colonic inflammation in high-fat diet (HFD)-induced obesity by modulation of peroxisome proliferator-activated receptor (PPAR)-γ. Male C57Bl/6J mice fed either a control diet (6.5% fat, CON) or a high-fat diet (24% fat, HFD) were divided into sedentary, voluntary exercise or voluntary exercise with PPAR-γ antagonist GW9662 (10 mg/kg/day). All interventions took place for 12 weeks. Compared with CON-sedentarymore » group, HFD-sedentary mice gained significantly more body weight and exhibited metabolic disorders. Molecular studies revealed that HFD-sedentary mice had increased expression of inflammatory mediators and activation of nuclear factor (NF)-κB in the colons, which were associated with decreased expression and activity of PPAR-γ. Voluntary exercise markedly attenuated body weight gain, improved metabolic disorders, and normalized the expression of inflammatory mediators and activation of NF-κB in the colons in HFD-mice while having no effects in CON-animals. Moreover, voluntary exercise significantly increased expression and activity of PPAR-γ in the colons in both HFD- and CON-animals. However, all of these beneficial effects induced by voluntary exercise were abolished by GW9662, which inhibited expression and activity of PPAR-γ. The results suggest that decreased PPAR-γ activity in the colon of HFD-induced obesity may facilitate the inflammatory response and colon carcinogenesis. Voluntary exercise prevents colonic inflammation in HFD-induced obesity by up-regulating PPAR-γ activity. - Highlights: • Obesity down-regulates PPAR-γ in the colon. • Down-regulated colonic PPAR-γ may facilitate inflammatory response. • Exercise prevents colonic inflammation in obesity by up-regulating PPAR-γ.« less

Impact of exercise programs among helicopter pilots with transient LBP.

PubMed

Andersen, Knut; Baardsen, Roald; Dalen, Ingvild; Larsen, Jan Petter

2017-06-20

Flight related low back pain (LBP) among helicopter pilots is frequent and may influence flight performance. Prolonged confined sitting during flights seems to weaken lumbar trunk (LT) muscles with associated secondary transient pain. Aim of the study was to investigate if structured training could improve muscular function and thus improve LBP related to flying. 39 helicopter pilots (35 men and 4 women), who reported flying related LBP on at least 1 of 3 missions last month, were allocated to two training programs over a 3-month period. Program A consisted of 10 exercises recommended for general LBP. Program B consisted of 4 exercises designed specifically to improve LT muscular endurance. The pilots were examined before and after the training using questionnaires for pain, function, quality of health and tests of LT muscular endurance as well as ultrasound measurements of the contractility of the lumbar multifidus muscle (LMM). Approximately half of the participants performed the training per-protocol. Participants in this subset group had comparable baseline characteristics as the total study sample. Pre and post analysis of all pilots included, showed participants had marked improvement in endurance and contractility of the LMM following training. Similarly, participants had improvement in function and quality of health. Participants in program B had significant improvement in pain, function and quality of health. This study indicates that participants who performed a three months exercise program had improved muscle endurance at the end of the program. The helicopter pilots also experienced improved function and quality of health. Identifier: NCT01788111 Registration date; February 5th, 2013, verified April 2016.

Prognostic Value of Exercise Treadmill Testing in Asymptomatic Chronic Nonischemic Mitral Regurgitation

PubMed Central

Supino, Phyllis G.; Borer, Jeffrey S.; Schuleri, Karlheinz; Gupta, Anuj; Hochreiter, Clare; Kligfield, Paul; Herrold, Edmund McM.; Preibisz, Jacek J.

2007-01-01

In many heart diseases, exercise treadmill testing(ETT) has useful functional correlates and/or prognostic value. However, its predictive value in mitral regurgitation(MR) is undefined. To determine whether ETT descriptors predict death or indications for mitral valve surgery among patients with MR, we prospectively followed, for 7±3 endpoint-free years, a cohort of 38 patients with chronic severe nonischemic MR who underwent modified Bruce ETT; all lacked surgical indications at study entry. Their baseline exercise descriptors also were compared with those from 46 patients with severe MR who, at entry, already had reached surgical indications. Endpoints during follow-up among the cohort included sudden death(n=1), heart failure symptoms(n=2), atrial fibrillation(n=4), LVEF<60%(n=2), LV systolic dimensions(IDs)≥45 mm(n=12) and LVIDs>40mm(n=11), LVEF<60%+LVIDs 45 mm(n=3), and heart failure+LVIDs 45mm+LVEF<60%(n=1). In univariate analysis, exercise duration(p=.004), chronotropic response(p=.007), percent predicted peak heart rate(p=.01) and heart rate recovery(p<.02) predicted events; in multivariate analysis, only exercise duration was predictive(p<.02). Average annual event risk was 5-fold lower(4.62%) with exercise duration≥15 minutes vs. <15 minutes(average annual risk=23.48%, p=.004). Relative risks among patients with and without exercise-inducible ST segment depression were comparable(≤1.3[NS]) whether defined at entry and/or during follow-up. Exercise duration, but not prevalence of exercise-inducible ST segment depression, was lower(p<.001) among patients with surgical indications at entry vs. initially endpoint-free patients. In conclusion, among asymptomatic patients with chronic severe nonischemic MR and no objective criteria for operation, progression to surgical indications generally is rapid. However, those with excellent exercise tolerance have a relatively benign course. Exercise-inducible ST segment depression has no prognostic value in this population. We followed, for 7±3 endpoint-free years, 38 patients with chronic severe nonischemic mitral regurgitation (MR) who underwent modified Bruce exercise treadmill testing (ETT) to determine whether ETT descriptors predict death or indications for mitral valve surgery. At study entry, all lacked surgical indications. Exercise duration independently predicted subsequent events; event risks among patients with and without exercise-inducible ST segment depression were comparable. We conclude that among asymptomatic patients with chronic severe nonischemic MR and no objective criteria for operation, those with excellent exercise tolerance have a relatively benign course. Exercise-inducible ST segment depression has no prognostic value in this population. PMID:17920370

Potential neurobiological benefits of exercise in chronic pain and posttraumatic stress disorder: Pilot study.

PubMed

Scioli-Salter, Erica; Forman, Daniel E; Otis, John D; Tun, Carlos; Allsup, Kelly; Marx, Christine E; Hauger, Richard L; Shipherd, Jillian C; Higgins, Diana; Tyzik, Anna; Rasmusson, Ann M

2016-01-01

This pilot study assessed the effects of cardiopulmonary exercise testing and cardiorespiratory fitness on plasma neuropeptide Y (NPY), allopregnanolone and pregnanolone (ALLO), cortisol, and dehydroepiandrosterone (DHEA), and their association with pain sensitivity. Medication-free trauma-exposed participants were either healthy (n = 7) or experiencing comorbid chronic pain/posttraumatic stress disorder (PTSD) (n = 5). Peak oxygen consumption (VO2) during exercise testing was used to characterize cardiorespiratory fitness. Peak VO2 correlated with baseline and peak NPY levels (r = 0.66, p < 0.05 and r = 0.69, p < 0.05, respectively), as well as exercise-induced changes in ALLO (r = 0.89, p < 0.001) and peak ALLO levels (r = 0.71, p < 0.01). NPY levels at the peak of exercise correlated with pain threshold 30 min after exercise (r = 0.65, p < 0.05), while exercise-induced increases in ALLO correlated with pain tolerance 30 min after exercise (r = 0.64, p < 0.05). In contrast, exercise-induced changes in cortisol and DHEA levels were inversely correlated with pain tolerance after exercise (r = -0.69, p < 0.05 and r = -0.58, p < 0.05, respectively). These data suggest that cardiorespiratory fitness is associated with higher plasma NPY levels and increased ALLO responses to exercise, which in turn relate to pain sensitivity. Future work will examine whether progressive exercise training increases cardiorespiratory fitness in association with increases in NPY and ALLO and reductions in pain sensitivity in chronic pain patients with PTSD.

Stress-Induced Depression Is Alleviated by Aerobic Exercise Through Up-Regulation of 5-Hydroxytryptamine 1A Receptors in Rats

PubMed Central

Kim, Tae Woon; Lim, Baek Vin; Baek, Dongjin; Ryu, Dong-Soo; Seo, Jin Hee

2015-01-01

Purpose: Stress is associated with depression, which induces many psychiatric disorders. Serotonin, also known as 5-hydroxy-tryptamine (5-HT), acts as a biochemical messenger and regulator in the brain. It also mediates several important physiological functions. Depression is closely associated with an overactive bladder. In the present study, we investigated the effect of treadmill exercise on stress-induced depression while focusing on the expression of 5-HT 1A (5-H1A) receptors in the dorsal raphe. Methods: Stress was induced by applying a 0.2-mA electric foot shock to rats. Each set of electric foot shocks comprised a 6-second shock duration that was repeated 10 times with a 30-second interval. Three sets of electric foot shocks were applied each day for 7 days. For the confirmation of depressive state, a forced swimming test was performed. To visualize the expression of 5-HT and tryptophan hydroxylase (TPH), immunohistochemistry for 5-HT and TPH in the dorsal raphe was performed. Expression of 5-H1A receptors was determined by western blot analysis. Results: A depressive state was induced by stress, and treadmill exercise alleviated the depression symptoms in the stress-induced rats. Expressions of 5-HT, TPH, and HT 1A in the dorsal raphe were reduced by the induction of stress. Treadmill exercise increased 5-HT, TPH, and HT 1A expressions in the stress-induced rats. Conclusions: Treadmill exercise enhanced 5-HT synthesis through the up-regulation of 5-HT1A receptors, and improved the stress-induced depression. In the present study, treadmill exercise improved depression symptoms by enhancing 5-HT1A receptor expression. The present results suggest that treadmill exercise might be helpful for the alleviation of overactive bladder and improve sexual function. PMID:25833478

Usefulness of automatic QT dispersion measurement for detecting exercise-induced myocardial ischemia.

PubMed

Takase, Bonpei; Masaki, Nobuyuki; Hattori, Hidemi; Ishihara, Masayuki; Kurita, Akira

2009-06-01

The electrocardiographic index of QT dispersion (QTd) is related to the occurrence of arrhythmia. In patients with suspected or known coronary artery disease, QTd may be affected by exercise. We investigated whether QTd that is automatically calculated by a newly developed computer system could be used as a marker of exercise-induced myocardial ischemia. The design of this study was prospective and observational. Eighty-three consecutive patients were enrolled in this study. Their QTd was measured at rest and after 3 min of exercise during exercise-stress Thallium-201 scintigraphy and compared with conventional ST-segment changes. The patients were classified into 4 groups (normal group, redistribution group, fixed defect group, redistribution with fixed defect group) based on the result of single photon emission computed tomography. As statistical analysis, one-way ANOVA with post-hoc Scheffe's method, receiver-operating characteristics (ROC) and multiple logistic regression analysis were performed. At rest, QTd was significantly greater (p<0.05) in the fixed defect group (52+/-21 ms) and the redistribution with fixed defect group (53+/-20 ms) than in the normal group (32+/-14 ms) and the redistribution group (31+/-16 ms). However, QTd tended to increase after exercise in the redistribution group, while QTd tended to decrease in the normal group, the fixed defect group, and the redistribution with fixed defect group (QTd after exercise, normal group, 28+/-17 ms, redistribution group, 35+/-19 ms, fixed defect group, 43+/-25 ms, redistribution with fixed defect group, 49+/-27 ms). Exercise significantly increased QTcd (RR interval-corrected QT dispersion) in the redistribution group. The best cut-off values of QTd and QTcd obtained from ROC curves for exercise-induced myocardial ischemia were 41.6 ms and 40.4 ms, respectively (Qtd--AUC 0.68, 95%CI 0.53- 0.83 and QTcd--AUC 0.67, 95%CI 0.55-0.80). Using these values as cut-off ones, QTd, QTcd, and conventional ST-segment change had comparable sensitivities and specificities for detecting exercise-induced myocardial ischemia (sensitivity - 60%, 58% and 49%, respectively;specificity - 78%, 80% and 83%, respectively). In addition, multiple logistic regression analysis showed that QTd (OR=2.01, 95%CI 1.15-4.10, p<0.05), QTcd (OR=2.12, 95% CI 1.02-4.30, p<0.05) and ST-segment change (OR=1.89, 95%CI 1.03-3.40, p<0.05), were the significantly associated with exercise-induced myocardial ischemia. QT dispersion and/or QTcd after exercise could be a useful marker for exercise-induced myocardial ischemia in routine clinical practice.

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.

Effect of exercise on patient specific abdominal aortic aneurysm flow topology and mixing.

PubMed

Arzani, Amirhossein; Les, Andrea S; Dalman, Ronald L; Shadden, Shawn C

2014-02-01

Computational fluid dynamics modeling was used to investigate changes in blood transport topology between rest and exercise conditions in five patient-specific abdominal aortic aneurysm models. MRI was used to provide the vascular anatomy and necessary boundary conditions for simulating blood velocity and pressure fields inside each model. Finite-time Lyapunov exponent fields and associated Lagrangian coherent structures were computed from blood velocity data and were used to compare features of the transport topology between rest and exercise both mechanistically and qualitatively. A mix-norm and mix-variance measure based on fresh blood distribution throughout the aneurysm over time were implemented to quantitatively compare mixing between rest and exercise. Exercise conditions resulted in higher and more uniform mixing and reduced the overall residence time in all aneurysms. Separated regions of recirculating flow were commonly observed in rest, and these regions were either reduced or removed by attached and unidirectional flow during exercise, or replaced with regional chaotic and transiently turbulent mixing, or persisted and even extended during exercise. The main factor that dictated the change in flow topology from rest to exercise was the behavior of the jet of blood penetrating into the aneurysm during systole. Copyright © 2013 John Wiley & Sons, Ltd.

Exercise-Induced Bronchoconstriction (EIB)

MedlinePlus

... Primary Immunodeficiency Disease Related Conditions Drug Guide Conditions Dictionary Just for Kids Library School Tools Videos Virtual ... Search AAAAI Breadcrumb navigation Home ▸ Conditions & Treatments ▸ Conditions Dictionary ▸ ... Share | Exercise-Induced Bronchoconstriction (EIB) « ...

Influence of vitamin C supplementation on oxidative stress and neutrophil inflammatory response in acute and regular exercise.

PubMed

Popovic, Ljiljana M; Mitic, Nebojsa R; Miric, Dijana; Bisevac, Boban; Miric, Mirjana; Popovic, Brankica

2015-01-01

Exercise induces a multitude of physiological and biochemical changes in blood affecting its redox status. Tissue damage resulting from exercise induces activation of inflammatory cells followed by the increased activity of myeloperoxidase (MPO) in circulation. Vitamin C readily scavenges free radicals and may thereby prevent oxidative damage of important biological macromolecules. The aim of this study was to examine the effect of vitamin C supplementation on oxidative stress and neutrophil inflammatory response induced by acute and regular exercise. Experiment was conducted on acute exercise group (performing Bruce Treadmill Protocol (BTP)) and regular training group. Markers of lipid peroxidation, malondialdehyde (MDA), MPO activity, and vitamin C status were estimated at rest and after BTP (acute exercise group) and before and after vitamin C supplementation in both groups. Our results showed increased postexercise Asc in serum independently of vitamin supplementation. They also showed that vitamin C can significantly decrease postexercise MDA level in both experimental groups. Increased postexercise MPO activity has been found in both groups and was not affected by vitamin C supplementation. We concluded that vitamin C supplementation can suppress lipid peroxidation process during exercise but cannot affect neutrophil inflammatory response in either exercise group.

The influence of exercise duration at VO2 max on the off-transient pulmonary oxygen uptake phase during high intensity running activity.

PubMed

Billat, V L; Hamard, L; Koralsztein, J P

2002-12-01

The purpose of this study was to examine the influence of time run at maximal oxygen uptake (VO2 max) on the off-transient pulmonary oxygen uptake phase after supra-lactate threshold runs. We hypothesised: 1) that among the velocities eliciting VO2 max there is a velocity threshold from which there is a slow component in the VO2-off transient, and 2) that at this velocity the longer the duration of this time at VO2 max (associated with an accumulated oxygen kinetics since VO2 can not overlap VO2 max), the longer is the off-transient phase of oxygen uptake kinetics. Nine long-distance runners performed five maximal tests on a synthetic track (400 m) while breathing through the COSMED K4b2 portable, telemetric metabolic analyser: i) an incremental test which determined VO2 max, the minimal velocity associated with VO2 max (vVO2 max) and the velocity at the lactate threshold (vLT), ii) and in a random order, four supra-lactate threshold runs performed until exhaustion at vLT + 25, 50, 75 and 100% of the difference between vLT and vVO2 max (vdelta25, vdelta50, vdelta75, vdelta100). At vdelta25, vdelta50 (= 91.0 +/- 0.9% vVO2 max) and vdelta75, an asymmetry was found between the VO2 on (double exponential) and off-transient (mono exponential) phases. Only at vdelta75 there was at positive relationship between the time run at VO2 max (%tlimtot) and the VO2 recovery time constant (Z = 1.8, P = 0.05). In conclusion, this study showed that among the velocities eliciting VO2 max, vdelta75 is the velocity at which the longer the duration of the time at VO2 max, the longer is the off-transient phase of oxygen uptake kinetics. It may be possible that at vdelta50 there is not an accumulated oxygen deficit during the plateau of VO2 at VO2 max and that the duration of the time at VO2 max during the exhaustive runs at vdelta100, could be too short to induce an accumulating oxygen deficit affecting the oxygen recovery.

Timeline of changes in adaptive physiological responses, at the level of energy expenditure, with progressive weight loss.

PubMed

Nymo, Siren; Coutinho, Silvia R; Torgersen, Linn-Christin H; Bomo, Ola J; Haugvaldstad, Ingrid; Truby, Helen; Kulseng, Bård; Martins, Catia

2018-07-01

Diet-induced weight loss (WL) is associated with reduced resting and non-resting energy expenditure (EE), driven not only by changes in body composition but also potentially by adaptive thermogenesis (AT). When exactly this happens, during progressive WL, remains unknown. The aim of this study was to determine the timeline of changes in RMR and exercise-induced EE (EIEE), stemming from changes in body composition v. the presence of AT, during WL with a very-low-energy diet (VLED). In all, thirty-one adults (eighteen men) with obesity (BMI: 37 (sem 4·5) kg/m2; age: 43 (sem 10) years) underwent 8 weeks of a VLED, followed by 4 weeks of weight maintenance. Body weight and composition, RMR, net EIEE (10, 25 and 50 W) and AT (for RMR (ATRMR) and EIEE (ATEIEE)) were measured at baseline, day 3 (2 (sem 1) % WL), after 5 and 10 % WL and at weeks 9 (16 (sem 2) %) and 13 (16 (sem 1) %). RMR and fat mass were significantly reduced for the first time at 5 % WL (12 (sem 8) d) (P<0·01 and P<0·001, respectively) and EIEE at 10 % WL (32 (sem 8) d), for all levels of power (P<0·05), and sustained up to week 13. ATRMR was transiently present at 10 % WL (-460 (sem 690) kJ/d, P<0·01). A fall in RMR should be anticipated at ≥5 % WL and a reduction in EIEE at ≥10 % WL. Transient ATRMR can be expected at 10 % WL. These physiological adaptations may make progressive WL difficult and will probably contribute to relapse.

Effects of furosemide on hemorheologic alterations induced by incremental treadmill exercise in thoroughbreds.

PubMed

Weiss, D J; Geor, R J; Burger, K

1996-06-01

To determine whether furosemide treatment altered the blood flow properties and serum and RBC electrolyte concentrations of Thoroughbreds during submaximal treadmill exercise. Thoroughbreds were subjected to submaximal treadmill exercise with and without treatment with furosemide (1 mg/kg of body weight, IV). 5 healthy Throughbreds that had raced within the past year and had no history of exercise-induced pulmonary hemorrhage. Venous blood samples were obtained before exercise, at treadmill speeds of 9 and 13 m/s, and 10 minutes after exercise, and hemorheologic and electrolyte test results were determined. Hemorheologic changes 60 minutes after furosemide administration included increased PCV, plasma total protein concentration, whole blood viscosity, mean RBC volume, and RBC potassium concentration, and decreased serum potassium concentration, serum chloride concentration, and RBC chloride concentration. Furosemide treatment attenuated the exercise-associated changes in RBC size, serum sodium concentration, serum potassium concentration, RBC potassium and chloride concentrations, and RBC density; exacerbated exercise-associated increases in whole blood viscosity; and had no effect on RBC filterability. The hemorheologic effects of furosemide probably occurred secondary to total body and transmembrane fluid and electrolyte fluxes and would not improve blood flow properties. The beneficial effects of furosemide treatment in reducing the severity of bleeding in horses with exercise-induced pulmonary hemorrhage cannot be explained by improved blood flow properties.

High protein diet maintains glucose production during exercise-induced energy deficit: a controlled trial

USDA-ARS?s Scientific Manuscript database

Inadequate energy intake induces changes in endogenous glucose production (GP) to preserve muscle mass. Whether addition provision of dietary protein modulates GP response to energy deficit is unclear. The objective was to determine whether exercise-induced energy deficit effects on glucose metaboli...

Flavanol-rich cocoa consumption enhances exercise-induced executive function improvements in humans.

PubMed

Tsukamoto, Hayato; Suga, Tadashi; Ishibashi, Aya; Takenaka, Saki; Tanaka, Daichi; Hirano, Yoshitaka; Hamaoka, Takafumi; Goto, Kazushige; Ebi, Kumiko; Isaka, Tadao; Hashimoto, Takeshi

2018-02-01

Aerobic exercise is known to acutely improve cognitive functions, such as executive function (EF) and memory function (MF). Additionally, consumption of flavanol-rich cocoa has been reported to acutely improve cognitive function. The aim of this study was to determine whether high cocoa flavanol (CF; HCF) consumption would enhance exercise-induced improvement in cognitive function. To test this hypothesis, we examined the combined effects of HCF consumption and moderate-intensity exercise on EF and MF during postexercise recovery. Ten healthy young men received either an HCF (563 mg of CF) or energy-matched low CF (LCF; 38 mg of CF) beverage 70 min before exercise in a single-blind counterbalanced manner. The men then performed moderate-intensity cycling exercise at 60% of peak oxygen uptake for 30 min. The participants performed a color-word Stroop task and face-name matching task to evaluate EF and MF, respectively, during six time periods throughout the experimental session. EF significantly improved immediately after exercise compared with before exercise in both conditions. However, EF was higher after HCF consumption than after LCF consumption during all time periods because HCF consumption improved EF before exercise. In contrast, HCF consumption and moderate-intensity exercise did not improve MF throughout the experiment. The present findings demonstrated that HCF consumption before moderate-intensity exercise could enhance exercise-induced improvement in EF, but not in MF. Therefore, we suggest that the combination of HCF consumption and aerobic exercise may be beneficial for improving EF. Copyright © 2017 Elsevier Inc. All rights reserved.

Exertional and CrossFit-Induced Rhabdomyolysis.

PubMed

Meyer, Michelle; Sundaram, Sneha; Schafhalter-Zoppoth, Ingeborg

2017-07-14

Few publications of exercise-induced rhabomyolysis currently exist in the medical literature besides case reports. However, this condition can be severe, resulting in hospitalization and IV fluid administration to prevent serious sequelae. This report describes a case of exercise-induced rhabdomyolysis caused by a CrossFit workout. A 31-year-old female presented with 2 days of bilateral upper extremity pain and soreness, which began 2 days after she completed a CrossFit workout. Workup revealed an elevated creatine phosphokinase (CPK) of 18 441 U/L, consistent with exercise-induced rhabdomyolysis, and elevated liver function tests and elevated D-dimer, although her renal function was normal. She was hospitalized for 2 days and treated with IV fluids. This case report demonstrates that CrossFit exercises can lead to rhabdomyolysis, highlighting a condition that may be underdiagnosed and underreported.

Muscle Damage following Maximal Eccentric Knee Extensions in Males and Females

PubMed Central

2016-01-01

Aim To investigate whether there is a sex difference in exercise induced muscle damage. Materials and Method Vastus Lateralis and patella tendon properties were measured in males and females using ultrasonography. During maximal voluntary eccentric knee extensions (12 reps x 6 sets), Vastus Lateralis fascicle lengthening and maximal voluntary eccentric knee extensions torque were recorded every 10° of knee joint angle (20–90°). Isometric torque, Creatine Kinase and muscle soreness were measured pre, post, 48, 96 and 168 hours post damage as markers of exercise induced muscle damage. Results Patella tendon stiffness and Vastus Lateralis fascicle lengthening were significantly higher in males compared to females (p<0.05). There was no sex difference in isometric torque loss and muscle soreness post exercise induced muscle damage (p>0.05). Creatine Kinase levels post exercise induced muscle damage were higher in males compared to females (p<0.05), and remained higher when maximal voluntary eccentric knee extension torque, relative to estimated quadriceps anatomical cross sectional area, was taken as a covariate (p<0.05). Conclusion Based on isometric torque loss, there is no sex difference in exercise induced muscle damage. The higher Creatine Kinase in males could not be explained by differences in maximal voluntary eccentric knee extension torque, Vastus Lateralis fascicle lengthening and patella tendon stiffness. Further research is required to understand the significant sex differences in Creatine Kinase levels following exercise induced muscle damage. PMID:26986066

Pronounced effects of acute endurance exercise on gene expression in resting and exercising human skeletal muscle.

PubMed

Catoire, Milène; Mensink, Marco; Boekschoten, Mark V; Hangelbroek, Roland; Müller, Michael; Schrauwen, Patrick; Kersten, Sander

2012-01-01

Regular physical activity positively influences whole body energy metabolism and substrate handling in exercising muscle. While it is recognized that the effects of exercise extend beyond exercising muscle, it is unclear to what extent exercise impacts non-exercising muscles. Here we investigated the effects of an acute endurance exercise bouts on gene expression in exercising and non-exercising human muscle. To that end, 12 male subjects aged 44-56 performed one hour of one-legged cycling at 50% W(max). Muscle biopsies were taken from the exercising and non-exercising leg before and immediately after exercise and analyzed by microarray. One-legged cycling raised plasma lactate, free fatty acids, cortisol, noradrenalin, and adrenalin levels. Surprisingly, acute endurance exercise not only caused pronounced gene expression changes in exercising muscle but also in non-exercising muscle. In the exercising leg the three most highly induced genes were all part of the NR4A family. Remarkably, many genes induced in non-exercising muscle were PPAR targets or related to PPAR signalling, including PDK4, ANGPTL4 and SLC22A5. Pathway analysis confirmed this finding. In conclusion, our data indicate that acute endurance exercise elicits pronounced changes in gene expression in non-exercising muscle, which are likely mediated by changes in circulating factors such as free fatty acids. The study points to a major influence of exercise beyond the contracting muscle.

A Systematic Review of the Literature on Screening for Exercise-Induced Asthma: Considerations for School Nurses

ERIC Educational Resources Information Center

Worrell, Kelly; Shaw, Michele R.; Postma, Julie; Katz, Janet R.

2015-01-01

Asthma is a major cause of illness, missed school days, and hospitalization in children. One type of asthma common in children is exercise-induced asthma (EIA). EIA causes airway narrowing with symptoms of cough and shortness of breath during exercise. The purpose of this article is to review the literature relevant to screening children and…

Effects of exercise intensity on plasma concentrations of appetite-regulating hormones: Potential mechanisms.

PubMed

Hazell, Tom J; Islam, Hashim; Townsend, Logan K; Schmale, Matt S; Copeland, Jennifer L

2016-03-01

The physiological control of appetite regulation involves circulating hormones with orexigenic (appetite-stimulating) and anorexigenic (appetite-inhibiting) properties that induce alterations in energy intake via perceptions of hunger and satiety. As the effectiveness of exercise to induce weight loss is a controversial topic, there is considerable interest in the effect of exercise on the appetite-regulating hormones such as acylated ghrelin, peptide YY (PYY), glucagon-like peptide-1 (GLP-1), and pancreatic polypeptide (PP). Research to date suggests short-term appetite regulation following a single exercise session is likely affected by decreases in acylated ghrelin and increases in PYY, GLP-1, and PP. Further, this exercise-induced response may be intensity-dependent. In an effort to guide future research, it is important to consider how exercise alters the circulating concentrations of these appetite-regulating hormones. Potential mechanisms include blood redistribution, sympathetic nervous system activity, gastrointestinal motility, cytokine release, free fatty acid concentrations, lactate production, and changes in plasma glucose and insulin concentrations. This review of relevant research suggests blood redistribution during exercise may be important for suppressing ghrelin, while other mechanisms involving cytokine release, changes in plasma glucose and insulin concentrations, SNS activity, and muscle metabolism likely mediate changes in the anorexigenic signals PYY and GLP-1. Overall, changes in appetite-regulating hormones following acute exercise appear to be intensity-dependent, with increasing intensity leading to a greater suppression of orexigenic signals and greater stimulation of anorexigenic signals. However, there is less research on how exercise-induced responses in appetite-regulating hormones differ between sexes or different age groups. A better understanding of how exercise intensity and workload affect appetite across the sexes and life stages will be a powerful tool in developing more successful strategies for managing weight. Copyright © 2015 Elsevier Ltd. All rights reserved.

Concentrically trained cyclists are not more susceptible to eccentric exercise-induced muscle damage than are stretch-shortening exercise-trained runners.

PubMed

Snieckus, Audrius; Kamandulis, Sigitas; Venckūnas, Tomas; Brazaitis, Marius; Volungevičius, Gintautas; Skurvydas, Albertas

2013-03-01

Here, we test the hypothesis that continuous concentric exercise training renders skeletal muscles more susceptible to damage in response to eccentric exercise. Elite road cyclists (CYC; n = 10, training experience 8.1 ± 2.0 years, age 22.9 ± 3.7 years), long-distance runners (LDR; n = 10, 9.9 ± 2.3 years, 24.4 ± 2.5 years), and healthy untrained (UT) men (n = 10; 22.4 ± 1.7 years) performed 100 submaximal eccentric contractions at constant angular velocity of 60° s(-1). Concentric isokinetic peak torque, isometric maximal voluntary contraction (MVC), and electrically induced knee extension torque were measured at baseline and immediately and 48 h after an eccentric exercise bout. Muscle soreness was assessed and plasma creatine kinase (CK) activity was measured at baseline and 48 h after exercise. Voluntary and electrically stimulated knee extension torque reduction were significantly greater (p < 0.05) in UT than in LDR and CYC. Immediately and 48 h after exercise, MVC decreased by 32 % and 20 % in UT, 20 % and 5 % in LDR, and 25 % and 6 % in CYC. Electrically induced 20 Hz torque decreased at the same times by 61 and 29 % in UT, 40 and 17 % in LDR, and 26 and 14 % in CYC. Muscle soreness and plasma CK activity 48 h after exercise did not differ significantly between athletes and UT subjects. In conclusion, even though elite endurance athletes are more resistant to eccentric exercise-induced muscle damage than are UT people, stretch-shortening exercise-trained LDR have no advantage over concentrically trained CYC.

Diet-induced increases in chemerin are attenuated by exercise and mediate the effect of diet on insulin and HOMA-IR.

PubMed

Lloyd, Jesse W; Zerfass, Kristy M; Heckstall, Ebony M; Evans, Kristin A

2015-10-01

Chemerin concentrations are elevated in obesity and associated with inflammation and insulin resistance. Exercise improves insulin sensitivity, which may be facilitated by changes in chemerin. We explored the effects of chronic exercise on chemerin levels in diet-induced obese mice. We divided 40 mice into 4 groups: high-fat diet/exercise, high-fat diet/sedentary, normal diet/exercise, and normal diet/sedentary. A 9-week dietary intervention was followed by a 12-week exercise intervention (treadmill run: 11 m/min for 30 min, 3×/week). We analyzed blood samples before and after the exercise intervention. We used t-tests and linear regression to examine changes in chemerin, insulin resistance, and inflammatory markers, and associations between changes in chemerin and all other biomarkers. Chemerin increased significantly across all mice over the 12-week intervention (mean ± SD = 40.7 ± 77.8%, p = 0.01), and this increase was smaller in the exercise versus sedentary mice (27.2 ± 83.9% versus 54.9 ± 70.5%, p = 0.29). The increase among the high-fat diet/exercise mice was ~44% lower than the increase among the high-fat diet/sedentary mice (55.7 ± 54.9% versus 99.8 ± 57.7%, p = 0.12). The high-fat diet mice showed significant increases in insulin (773.5 ± 1286.6%, p < 0.0001) and homeostatic model assessment of insulin resistance (HOMA-IR; 846.5 ± 1723.3%, p < 0.01). Mediation analyses showed that increases in chemerin explained a substantial amount of the diet-induced increases in insulin and HOMA-IR. Chronic exercise may attenuate diet-driven increases in circulating chemerin, and the insulin resistance associated with a high-fat diet may be mediated by diet-induced increases in chemerin.

Exercise reduces diet-induced cognitive decline and increases hippocampal brain-derived neurotrophic factor in CA3 neurons

PubMed Central

Noble, Emily E.; Mavanji, Vijayakumar; Little, Morgan R.; Billington, Charles J.; Kotz, Catherine M.; Wang, ChuanFeng

2014-01-01

Background Previous studies have shown that a western diet impairs, whereas physical exercise enhances hippocampus-dependent learning and memory. Both diet and exercise influence expression of hippocampal brain-derived neurotrophic factor (BDNF), which is associated with improved cognition. We hypothesized that exercise reverses diet-induced cognitive decline while increasing hippocampal BDNF. Methods To test the effects of exercise on hippocampal-dependent memory, we compared cognitive scores of Sprague-Dawley rats exercised by voluntary running wheel (RW) access or forced treadmill (TM) to sedentary (Sed) animals. Memory was tested by two-way active avoidance test (TWAA), in which animals are exposed to a brief shock in a specific chamber area. When an animal avoids, escapes or has reduced latency to do either, this is considered a measure of memory. In a second experiment, rats were fed either a high-fat diet or control diet for 16 weeks, then randomly assigned to running wheel access or sedentary condition, and TWAA memory was tested once a week for seven weeks of exercise intervention. Results Both groups of exercised animals had improved memory as indicated by reduced latency to avoid and escape shock, and increased avoid and escape episodes (p<0.05). Exposure to a high-fat diet resulted in poor performance during both the acquisition and retrieval phases of the memory test as compared to controls. Exercise reversed high-fat diet-induced memory impairment, and increased brain-derived neurotrophic factor (BDNF) in neurons of the hippocampal CA3 region. Conclusions These data suggest that exercise improves memory retrieval, particularly with respect to avoiding aversive stimuli, and may be beneficial in protecting against diet induced cognitive decline, likely via elevated BDNF in neurons of the CA3 region. PMID:24755094

Exercise reduces diet-induced cognitive decline and increases hippocampal brain-derived neurotrophic factor in CA3 neurons.

PubMed

Noble, Emily E; Mavanji, Vijayakumar; Little, Morgan R; Billington, Charles J; Kotz, Catherine M; Wang, ChuanFeng

2014-10-01

Previous studies have shown that a western diet impairs, whereas physical exercise enhances hippocampus-dependent learning and memory. Both diet and exercise influence expression of hippocampal brain-derived neurotrophic factor (BDNF), which is associated with improved cognition. We hypothesized that exercise reverses diet-induced cognitive decline while increasing hippocampal BDNF. To test the effects of exercise on hippocampal-dependent memory, we compared cognitive scores of Sprague-Dawley rats exercised by voluntary running wheel (RW) access or forced treadmill (TM) to sedentary (Sed) animals. Memory was tested by two-way active avoidance test (TWAA), in which animals are exposed to a brief shock in a specific chamber area. When an animal avoids, escapes or has reduced latency to do either, this is considered a measure of memory. In a second experiment, rats were fed either a high-fat diet or control diet for 16 weeks, then randomly assigned to running wheel access or sedentary condition, and TWAA memory was tested once a week for 7 weeks of exercise intervention. Both groups of exercised animals had improved memory as indicated by reduced latency to avoid and escape shock, and increased avoid and escape episodes (p<0.05). Exposure to a high-fat diet resulted in poor performance during both the acquisition and retrieval phases of the memory test as compared to controls. Exercise reversed high-fat diet-induced memory impairment, and increased brain-derived neurotrophic factor (BDNF) in neurons of the hippocampal CA3 region. These data suggest that exercise improves memory retrieval, particularly with respect to avoiding aversive stimuli, and may be beneficial in protecting against diet induced cognitive decline, likely via elevated BDNF in neurons of the CA3 region. Published by Elsevier Inc.

Exercise-Induced Skeletal Muscle Remodeling and Metabolic Adaptation: Redox Signaling and Role of Autophagy

PubMed Central

Giammarioli, Anna Maria; Chiandotto, Sergio; Spoletini, Ilaria

2014-01-01

Abstract Significance: Skeletal muscle is a highly plastic tissue. Exercise evokes signaling pathways that strongly modify myofiber metabolism and physiological and contractile properties of skeletal muscle. Regular physical activity is beneficial for health and is highly recommended for the prevention of several chronic conditions. In this review, we have focused our attention on the pathways that are known to mediate physical training-induced plasticity. Recent Advances: An important role for redox signaling has recently been proposed in exercise-mediated muscle remodeling and peroxisome proliferator-activated receptor γ (PPARγ) coactivator-1α (PGC-1α) activation. Still more currently, autophagy has also been found to be involved in metabolic adaptation to exercise. Critical Issues: Both redox signaling and autophagy are processes with ambivalent effects; they can be detrimental and beneficial, depending on their delicate balance. As such, understanding their role in the chain of events induced by exercise and leading to skeletal muscle remodeling is a very complicated matter. Moreover, the study of the signaling induced by exercise is made even more difficult by the fact that exercise can be performed with several different modalities, with this having different repercussions on adaptation. Future Directions: Unraveling the complexity of the molecular signaling triggered by exercise on skeletal muscle is crucial in order to define the therapeutic potentiality of physical training and to identify new pharmacological compounds that are able to reproduce some beneficial effects of exercise. In evaluating the effect of new “exercise mimetics,” it will also be necessary to take into account the involvement of reactive oxygen species, reactive nitrogen species, and autophagy and their controversial effects. Antioxid. Redox Signal. 21, 154–176. PMID:24450966

Effects of Hypertension and Exercise on Cardiac Proteome Remodelling

PubMed Central

Petriz, Bernardo A.; Franco, Octavio L.

2014-01-01

Left ventricle hypertrophy is a common outcome of pressure overload stimulus closely associated with hypertension. This process is triggered by adverse molecular signalling, gene expression, and proteome alteration. Proteomic research has revealed that several molecular targets are associated with pathologic cardiac hypertrophy, including angiotensin II, endothelin-1 and isoproterenol. Several metabolic, contractile, and stress-related proteins are shown to be altered in cardiac hypertrophy derived by hypertension. On the other hand, exercise is a nonpharmacologic agent used for hypertension treatment, where cardiac hypertrophy induced by exercise training is characterized by improvement in cardiac function and resistance against ischemic insult. Despite the scarcity of proteomic research performed with exercise, healthy and pathologic heart proteomes are shown to be modulated in a completely different way. Hence, the altered proteome induced by exercise is mostly associated with cardioprotective aspects such as contractile and metabolic improvement and physiologic cardiac hypertrophy. The present review, therefore, describes relevant studies involving the molecular characteristics and alterations from hypertensive-induced and exercise-induced hypertrophy, as well as the main proteomic research performed in this field. Furthermore, proteomic research into the effect of hypertension on other target-demerged organs is examined. PMID:24877123

The endocannabinoid system mediates aerobic exercise-induced antinociception in rats.

PubMed

Galdino, Giovane; Romero, Thiago R L; Silva, José Felipe P; Aguiar, Daniele C; de Paula, Ana Maria; Cruz, Jader S; Parrella, Cosimo; Piscitelli, Fabiana; Duarte, Igor D; Di Marzo, Vincenzo; Perez, Andrea C

2014-02-01

Exercise-induced antinociception is widely described in the literature, but the mechanisms involved in this phenomenon are poorly understood. Systemic (s.c.) and central (i.t., i.c.v.) pretreatment with CB₁ and CB₂ cannabinoid receptor antagonists (AM251 and AM630) blocked the antinociception induced by an aerobic exercise (AE) protocol in both mechanical and thermal nociceptive tests. Western blot analysis revealed an increase and activation of CB₁ receptors in the rat brain, and immunofluorescence analysis demonstrated an increase of activation and expression of CB₁ receptors in neurons of the periaqueductal gray matter (PAG) after exercise. Additionally, pretreatment (s.c., i.t. and i.c.v.) with endocannabinoid metabolizing enzyme inhibitors (MAFP and JZL184) and an anandamide reuptake inhibitor (VDM11) prolonged and intensified this antinociceptive effect. These results indicate that exercise could activate the endocannabinoid system, producing antinociception. Supporting this hypothesis, liquid-chromatography/mass-spectrometry measurements demonstrated that plasma levels of endocannabinoids (anandamide and 2-arachidonoylglycerol) and of anandamide-related mediators (palmitoylethanolamide and oleoylethanolamide) were increased after AE. Therefore, these results suggest that the endocannabinoid system mediates aerobic exercise-induced antinociception at peripheral and central levels. Copyright © 2013 Elsevier Ltd. All rights reserved.

Salivary cortisol and testosterone responses to resistance and plyometric exercise in 12- to 14-year-old boys.

PubMed

Klentrou, Panagiota; Giannopoulou, Angeliki; McKinlay, Brandon J; Wallace, Phillip; Muir, Cameron; Falk, Bareket; Mack, Diane

2016-07-01

This study examined changes in salivary testosterone and cortisol following resistance and plyometric exercise protocols in active boys. In a crossover experimental design, 26 peri-pubertal (12- to 14-year-old) soccer players performed 2 exercise trials in random order, on separate evenings, 1 week apart. Each trial included a 30 min control session followed by 30 min of either resistance or plyometric exercise. Saliva was collected at baseline, post-control (i.e., pre-exercise), and 5 and 30 min post-exercise. There were no significant differences in the baseline hormone concentrations between trials or between weeks (p > 0.05). A significant effect for time was found for testosterone (p = 0.02, [Formula: see text] = 0.14), which increased from pre-exercise to 5 min post-exercise in both the resistance (27% ± 5%) and plyometric (12% ± 6%) protocols. Cortisol decreased to a similar extent in both trials (p = 0.009, [Formula: see text] = 0.19) from baseline to post-control and then to 5 min post-exercise, following its typical circadian decrease in the evening hours. However, a significant protocol-by-time interaction was observed for cortisol, which increased 30 min after the plyometrics (+31% ± 12%) but continued to decrease following the resistance protocol (-21% ± 5%). Our results suggest that in young male athletes, multiple modes of exercise can lead to a transient anabolic state, thus maximizing the beneficial effects on growth and development, when exercise is performed in the evening hours.

Systolic and Diastolic Left Ventricular Mechanics during and after Resistance Exercise.

PubMed

Stöhr, Eric J; Stembridge, Mike; Shave, Rob; Samuel, T Jake; Stone, Keeron; Esformes, Joseph I

2017-10-01

To improve the current understanding of the impact of resistance exercise on the heart, by examining the acute responses of left ventricular (LV) strain, twist, and untwisting rate ("LV mechanics"). LV echocardiographic images were recorded in systole and diastole before, during and immediately after (7-12 s) double-leg press exercise at two intensities (30% and 60% of maximum strength, one-repetition maximum). Speckle tracking analysis generated LV strain, twist, and untwisting rate data. Additionally, beat-by-beat blood pressure was recorded and systemic vascular resistance (SVR) and LV wall stress were calculated. Responses in both exercise trials were statistically similar (P > 0.05). During effort, stroke volume decreased, whereas SVR and LV wall stress increased (P < 0.05). Immediately after effort, stroke volume returned to baseline, whereas SVR and wall stress decreased (P < 0.05). Similarly, acute exercise was accompanied by a significant decrease in systolic parameters of LV muscle mechanics (P < 0.05). However, diastolic parameters, including LV untwisting rate, were statistically unaltered (P > 0.05). Immediately after exercise, systolic LV mechanics returned to baseline levels (P < 0.05) but LV untwisting rate increased significantly (P < 0.05). A single, acute bout of double-leg press resistance exercise transiently reduces systolic LV mechanics, but increases diastolic mechanics after exercise, suggesting that resistance exercise has a differential impact on systolic and diastolic heart muscle function. The findings may explain why acute resistance exercise has been associated with reduced stroke volume but chronic exercise training may result in increased LV volumes.

Effect of short-term training on GLUT-4 mRNA and protein expression in human skeletal muscle.

PubMed

Kraniou, Giorgos N; Cameron-Smith, David; Hargreaves, Mark

2004-09-01

Six untrained, male subjects (23 +/- 1 years old, 84 +/- 5 kg, (O(2)peak)= 3.7 +/- 0.8 l min(-1)) exercised for 60 min at 75 +/- 1%(O(2)peak) on 7 consecutive days. Muscle samples were obtained before the start of cycle exercise training and 24 h after the first and seventh exercise sessions and analysed for citrate synthase activity, glycogen and glucose transporter 4 (GLUT-4) mRNA and protein expression. Exercise training increased (P < 0.05) citrate synthase by approximately 20% and muscle glycogen concentration by approximately 40%. GLUT-4 mRNA levels 24 h after the first and seventh exercise sessions were similar to those measured before the start of exercise training. In contrast, GLUT-4 protein expression was increased after 7 days of exercise training (12.4 +/- 1.5 versus 3.4 +/- 1.0 arbitray units (a.u.), P < 0.05) and although it tended to be higher 24 h after the first exercise session (6.0 +/- 3.0 versus 3.4 +/- 1.0 a.u.), this was not significantly different (P= 0.09). These results support the suggestion that the adaptive increase in skeletal muscle GLUT-4 protein expression with short-term exercise training arises from the repeated, transient increases in GLUT-gene transcription following each exercise bout leading to a gradual accumulation of GLUT-4 protein, despite GLUT-4 mRNA returning to basal levels between exercise stimuli.

Efficacy of a heat exchanger mask in cold exercise-induced asthma.

PubMed

Beuther, David A; Martin, Richard J

2006-05-01

To determine the efficacy of a novel mask device in limiting cold air exercise-induced decline in lung function in subjects with a history of exercise-induced asthma (EIA). In spite of appropriate medical therapy, many asthma patients are limited in cold weather activities. In study 1, 13 asthmatic subjects performed two randomized, single-blind treadmill exercise tests while breathing cold air (- 25 to - 15 degrees C) through a placebo or active heat exchanger mask. In study 2, five subjects with EIA performed three treadmill exercise tests while breathing cold air: one test using the heat exchanger mask, one test without the mask but with albuterol pretreatment, and one test with neither the mask nor albuterol pretreatment (unprotected exercise). For all studies, spirometry was performed before and at 5, 15, and 30 min after exercise challenge. For both studies, a total of 15 subjects with a history of asthma symptoms during cold air exercise were recruited. In study 1, the mean decrease (+/- SE) in FEV1 was 19 +/- 4.9% with placebo, and 4.3 +/- 1.6% with the active device (p = 0.0002). The mean decrease in maximum mid-expiratory flow (FEF(25-75)) was 31 +/- 5.7% with placebo and 4.7 +/- 1.7% with the active device (p = 0.0002). In study 2, the mean decrease in FEV1 was 6.3 +/- 3.9%, 11 +/- 3.7%, and 28 +/- 10% for the heat exchanger mask, albuterol pretreatment, and unprotected exercises, respectively (p = 0.4375 for mask vs albuterol, p = 0.0625 for mask vs unprotected exercise). The mean decrease in FEF(25-75) was 10 +/- 4.8%, 23 +/- 6.0%, and 36 +/- 11%, respectively (p = 0.0625 for mask vs albuterol, p = 0.0625 for mask vs unprotected exercise). This heat exchanger mask blocks cold exercise-induced decline in lung function at least as effectively as albuterol pretreatment.

Head to Head Comparison of Short-Term Treatment with the NAD(+) Precursor Nicotinamide Mononucleotide (NMN) and 6 Weeks of Exercise in Obese Female Mice.

PubMed

Uddin, Golam M; Youngson, Neil A; Sinclair, David A; Morris, Margaret J

2016-01-01

Obesity is well known to be a major cause of several chronic metabolic diseases, which can be partially counteracted by exercise. This is due, in part, to an upregulation of mitochondrial activity through increased nicotinamide adenine dinucleotide (NAD(+)). Recent studies have shown that NAD(+) levels can be increased by using the NAD(+) precursor, nicotinamide mononucleotide (NMN) leading to the suggestion that NMN could be a useful intervention in diet related metabolic disorders. In this study we compared the metabolic, and especially mitochondrial-associated, effects of exercise and NMN in ameliorating the consequences of high-fat diet (HFD) induced obesity in mice. Sixty female 5 week old C57BL6/J mice were allocated across five groups: Chow sedentary: CS; Chow exercise: CEX; HFD sedentary: HS; HFD NMN: HNMN; HFD exercise: HEX (12/group). After 6 weeks of diet, exercise groups underwent treadmill exercise (15 m/min for 45 min), 6 days per week for 6 weeks. NMN or vehicle (500 mg/kg body weight) was injected (i.p.) daily for the last 17 days. No significant alteration in body weight was observed in response to exercise or NMN. The HFD significantly altered adiposity, glucose tolerance, plasma insulin, NADH levels and citrate synthase activity in muscle and liver. HEX and HNMN groups both showed significantly improved glucose tolerance compared to the HS group. NAD(+) levels were increased significantly both in muscle and liver by NMN whereas exercise increased NAD(+) only in muscle. Both NMN and exercise ameliorated the HFD-induced reduction in liver citrate synthase activity. However, exercise, but not NMN, ameliorated citrate synthase activity in muscle. Overall these data suggest that while exercise and NMN-supplementation can induce similar reversal of the glucose intolerance induced by obesity, they are associated with tissue-specific effects and differential alterations to mitochondrial function in muscle and liver.

Single swim sessions in C. elegans induce key features of mammalian exercise.

PubMed

Laranjeiro, Ricardo; Harinath, Girish; Burke, Daniel; Braeckman, Bart P; Driscoll, Monica

2017-04-10

Exercise exerts remarkably powerful effects on metabolism and health, with anti-disease and anti-aging outcomes. Pharmacological manipulation of exercise benefit circuits might improve the health of the sedentary and the aging populations. Still, how exercised muscle signals to induce system-wide health improvement remains poorly understood. With a long-term interest in interventions that promote animal-wide health improvement, we sought to define exercise options for Caenorhabditis elegans. Here, we report on the impact of single swim sessions on C. elegans physiology. We used microcalorimetry to show that C. elegans swimming has a greater energy cost than crawling. Animals that swam continuously for 90 min specifically consumed muscle fat supplies and exhibited post-swim locomotory fatigue, with both muscle fat depletion and fatigue indicators recovering within 1 hour of exercise cessation. Quantitative polymerase chain reaction (qPCR) transcript analyses also suggested an increase in fat metabolism during the swim, followed by the downregulation of specific carbohydrate metabolism transcripts in the hours post-exercise. During a 90 min swim, muscle mitochondria matrix environments became more oxidized, as visualized by a localized mitochondrial reduction-oxidation-sensitive green fluorescent protein reporter. qPCR data supported specific transcriptional changes in oxidative stress defense genes during and immediately after a swim. Consistent with potential antioxidant defense induction, we found that a single swim session sufficed to confer protection against juglone-induced oxidative stress inflicted 4 hours post-exercise. In addition to showing that even a single swim exercise bout confers physiological changes that increase robustness, our data reveal that acute swimming-induced changes share common features with some acute exercise responses reported in humans. Overall, our data validate an easily implemented swim experience as C. elegans exercise, setting the foundation for exploiting the experimental advantages of this model to genetically or pharmacologically identify the exercise-associated molecules and signaling pathways that confer system-wide health benefits.

Parkin is required for exercise-induced mitophagy in muscle: impact of aging.

PubMed

Chen, Chris Chin Wah; Erlich, Avigail T; Crilly, Matthew J; Hood, David A

2018-05-29

The maintenance of muscle health with advancing age is dependent on mitochondrial homeostasis. While reductions in mitochondrial biogenesis have been observed with age, less is known regarding organelle degradation. Parkin is an E3 ubiquitin ligase implicated in mitophagy, but few studies have examined Parkin's contribution to mitochondrial turnover in muscle. Wild type (WT) and Parkin knockout (KO) mice were used to delineate a role for Parkin-mediated mitochondrial degradation in aged muscle, in concurrence with exercise. Aged animals exhibited declines in muscle mass and mitochondrial content, paralleled by a nuclear environment endorsing the transcriptional repression of mitochondrial biogenesis. Mitophagic signaling was enhanced following acute endurance exercise in young WT mice, but was abolished in the absence of Parkin. Basal mitophagy flux of the autophagosomal protein LC3II was augmented in aged animals, but did not increase additionally with exercise when compared to young animals. In the absence of Parkin, exercise increased the nuclear localization of PARIS, corresponding to a decrease in nuclear PGC-1α. Remarkably, exercise enhanced mitochondrial ubiquitination in both young WT and KO animals. This suggested compensation of alternative ubiquitin ligases that were, however, unable to restore the diminished exercise-induced mitophagy in KO mice. Under basal conditions, we demonstrated that Parkin was required for mitochondrial Mfn2 ubiquitination. We also observed an abrogation of exercise-induced mitophagy in aged muscle. Our results demonstrate that acute exercise-induced mitophagy is dependent on Parkin, and attenuated with age, which likely contributes to changes in mitochondrial content and quality in aging muscle.

Endurance exercise modulates levodopa induced growth hormone release in patients with Parkinson's disease.

PubMed

Müller, Thomas; Welnic, Jacub; Woitalla, Dirk; Muhlack, Siegfried

2007-07-11

Acute levodopa (LD) application and exercise release human growth hormone (GH). An earlier trial showed, that combined stimulus of exercise and LD administration is the best provocative test for GH response in healthy participants. Objective was to show this combined effect of LD application and exercise on GH response and to investigate the impact on LD metabolism in 20 previously treated patients with Parkinson's disease (PD). We measured GH- and LD plasma concentrations following soluble 200 mg LD/50 mg benserazide administration during endurance exercise and rest on two separate consecutive days. GH concentrations significantly increased on both days, but GH release was significantly delayed during rest. LD metabolism was not altered due to exercise in a clinical relevant manner. Exercise induced a significant faster LD stimulated GH release in comparison with the rest condition. We did not find the supposed increase of LD induced GH release by endurance exercise. We assume, that only a limited amount of GH is available for GH release in the anterior pituitary following an acute 200 mg LD administration. GH disposal also depends on growth hormone releasing hormone (GHRH), which is secreted into hypothalamic portal capillaries. During the exercise condition, the resulting higher blood pressure supports blood flow and thus GHRH transport towards the GH producing cells in the pituitary. This might additionally have caused the significant faster GH release during exercise.

Exercise induces cerebral VEGF and angiogenesis via the lactate receptor HCAR1

PubMed Central

Morland, Cecilie; Andersson, Krister A.; Haugen, Øyvind P.; Hadzic, Alena; Kleppa, Liv; Gille, Andreas; Rinholm, Johanne E.; Palibrk, Vuk; Diget, Elisabeth H.; Kennedy, Lauritz H.; Stølen, Tomas; Hennestad, Eivind; Moldestad, Olve; Cai, Yiqing; Puchades, Maja; Offermanns, Stefan; Vervaeke, Koen; Bjørås, Magnar; Wisløff, Ulrik; Storm-Mathisen, Jon; Bergersen, Linda H.

2017-01-01

Physical exercise can improve brain function and delay neurodegeneration; however, the initial signal from muscle to brain is unknown. Here we show that the lactate receptor (HCAR1) is highly enriched in pial fibroblast-like cells that line the vessels supplying blood to the brain, and in pericyte-like cells along intracerebral microvessels. Activation of HCAR1 enhances cerebral vascular endothelial growth factor A (VEGFA) and cerebral angiogenesis. High-intensity interval exercise (5 days weekly for 7 weeks), as well as L-lactate subcutaneous injection that leads to an increase in blood lactate levels similar to exercise, increases brain VEGFA protein and capillary density in wild-type mice, but not in knockout mice lacking HCAR1. In contrast, skeletal muscle shows no vascular HCAR1 expression and no HCAR1-dependent change in vascularization induced by exercise or lactate. Thus, we demonstrate that a substance released by exercising skeletal muscle induces supportive effects in brain through an identified receptor. PMID:28534495

Exercise induces cerebral VEGF and angiogenesis via the lactate receptor HCAR1.

PubMed

Morland, Cecilie; Andersson, Krister A; Haugen, Øyvind P; Hadzic, Alena; Kleppa, Liv; Gille, Andreas; Rinholm, Johanne E; Palibrk, Vuk; Diget, Elisabeth H; Kennedy, Lauritz H; Stølen, Tomas; Hennestad, Eivind; Moldestad, Olve; Cai, Yiqing; Puchades, Maja; Offermanns, Stefan; Vervaeke, Koen; Bjørås, Magnar; Wisløff, Ulrik; Storm-Mathisen, Jon; Bergersen, Linda H

2017-05-23

Physical exercise can improve brain function and delay neurodegeneration; however, the initial signal from muscle to brain is unknown. Here we show that the lactate receptor (HCAR1) is highly enriched in pial fibroblast-like cells that line the vessels supplying blood to the brain, and in pericyte-like cells along intracerebral microvessels. Activation of HCAR1 enhances cerebral vascular endothelial growth factor A (VEGFA) and cerebral angiogenesis. High-intensity interval exercise (5 days weekly for 7 weeks), as well as L-lactate subcutaneous injection that leads to an increase in blood lactate levels similar to exercise, increases brain VEGFA protein and capillary density in wild-type mice, but not in knockout mice lacking HCAR1. In contrast, skeletal muscle shows no vascular HCAR1 expression and no HCAR1-dependent change in vascularization induced by exercise or lactate. Thus, we demonstrate that a substance released by exercising skeletal muscle induces supportive effects in brain through an identified receptor.

The Prevalence of Exercise Prescription-Related Course Offerings in United States Pharmacy School Curricula: Exercise is Medicine

ERIC Educational Resources Information Center

Dirks-Naylor, Amie J.; Griffiths, Carrie L.; Gibson, Jacob L.; Luu, Jacqueline A.

2016-01-01

Exercise training has proven to be beneficial in the prevention of disease. In addition, exercise can improve the pathogenesis and symptoms associated with a variety of chronic disease states and can attenuate drug-induced adverse effects. Exercise is a drug-free polypill. Because the benefits of exercise are clear and profound, Exercise is…

Sudden cardiac death: the pro-arrhythmic interaction of an acute loading with an underlying substrate.

PubMed

Sutherland, George R

2017-10-21

Sudden cardiac death (SCD) is a complex phenomenon, occurring either in apparently normal individuals or in those where there is a recognized underlying cardiac abnormality. In both groups, the lethal arrhythmia has frequently been related to the physiologic trigger of either exercise or stress. Prior research into SCD has focused mainly on a combination of identifying either vulnerable myocardial substrates; pharmacological approaches to altering electrical activation/repolarisation in substrates; or the suppression of induced lethal arrhythmias with implantable defibrillators. However, it has been suggested that in a significant number of cases, the interaction of a transient induced trigger with a pre-existing electrical or mechanical substrate is the basis for the induction of the sustained lethal arrhythmia. In this manuscript we will discuss the precise mechanisms whereby one of such potential physiologic trigger: an acute change in systolic blood pressure, can induce a sequence of alterations in global and local cardiac mechanics which in turn result in regional left ventricular post-systolic deformation which, mediated (through stretch-induced changes in local mechano-electrical coupling) provokes local electrical after-depolarisations which can spill over into complex runs of premature ventricular beats. These local acute pressure/stretch induced runs of ventricular ectopy originate in either basal or apical normal myocardium and, in combination with a co-existing distal pro-arrhymic substrate, can interact to induce a lethal arrhythmia. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2016. For Permissions, please email: journals.permissions@oup.com.

Effects of naloxone opiate blockade on the immunomodulation induced by exercise in rats.

PubMed

Bouix, O; elMezouini, M; Orsetti, A

1995-01-01

The purpose of this study was to examine the possible involvement of the endogenous opiate system in the changes in immune competence induced by isolated exercise. Male untrained rats were subjected to a 2.5 hours swimming exercise bout. Animals were killed 15 min after the end of the exercise. The concentration of leukocytes, lymphocytes, monocytes and granulocytes and T4 (T-helper), T8 (T-suppressor/cytotoxic), interleukin-2 receptor (IL-2R) and transferrin receptor (TrfR) positive lymphocytes were determined both in peripheral blood and spleen by flow cytometric analysis. Exercise resulted in a significant decrease in 1) blood lymphocyte and splenic granulocyte number (p < 0.05), 2) blood and splenic T4 positive lymphocytes and T4/T8 ratio (p < 0.05), and 3) blood and splenic IL-2R and TrfR positive lymphocytes (p < 0.05). The injection of the opiate blocker naloxone to exercising rats induced a decrease in the concentration and proportion of T8 positive lymphocytes, thereby restoring a normal T4/T8 ratio both in peripheral blood and spleen. Naloxone had no effect in control animals. The concentration and proportion of IL-2R and TrfR positive lymphocytes were not affected by naloxone. The mechanisms of the immunomodulation induced by isolated intense exercise are unclear. These data suggest that endogenous opiates participate in the alteration of cell-mediated immunity associated with exercise by modulating the T8 (suppressor/cytotoxic)-cell activity.

PGC-1α and exercise intensity dependent adaptations in mouse skeletal muscle

PubMed Central

Dethlefsen, Maja Munk; Bangsbo, Jens; Pilegaard, Henriette

2017-01-01

The aim of the present study was to examine the role of PGC-1α in intensity dependent exercise and exercise training-induced metabolic adaptations in mouse skeletal muscle. Whole body PGC-1α knockout (KO) and littermate wildtype (WT) mice performed a single treadmill running bout at either low intensity (LI) for 40 min or moderate intensity (MI) for 20 min. Blood and quadriceps muscles were removed either immediately after exercise or at 3h or 6h into recovery from exercise and from resting controls. In addition PGC-1α KO and littermate WT mice were exercise trained at either low intensity (LIT) for 40 min or at moderate intensity (MIT) for 20 min 2 times pr. day for 5 weeks. In the first and the last week of the intervention period, mice performed a graded running endurance test. Quadriceps muscles were removed before and after the training period for analyses. The acute exercise bout elicited intensity dependent increases in LC3I and LC3II protein and intensity independent decrease in p62 protein in skeletal muscle late in recovery and increased LC3II with exercise training independent of exercise intensity and volume in WT mice. Furthermore, acute exercise and exercise training did not increase LC3I and LC3II protein in PGC-1α KO. In addition, exercise-induced mRNA responses of PGC-1α isoforms were intensity dependent. In conclusion, these findings indicate that exercise intensity affected autophagy markers differently in skeletal muscle and suggest that PGC-1α regulates both acute and exercise training-induced autophagy in skeletal muscle potentially in a PGC-1α isoform specific manner. PMID:29049322

Exercise-induced brachial artery vasodilation: effects of antioxidants and exercise training in elderly men

PubMed Central

Donato, Anthony J.; Uberoi, Abhimanyu; Bailey, Damian M.; Walter Wray, D.

2010-01-01

Aging, vascular function, and exercise are thought to have a common link in oxidative stress. Of the 28 subjects studied (young, 26 ± 2 yr; old, 71 ± 6 yr), 12 took part in a study to validate an antioxidant cocktail (AOC: vitamins C, E, and α-lipoic acid), while the remaining 8 young and 8 old subjects performed submaximal forearm handgrip exercise with placebo or AOC. Old subjects repeated forearm exercise with placebo or AOC following knee-extensor (KE) exercise training. Brachial arterial diameter and blood velocity (Doppler ultrasound) were measured at rest and during exercise. During handgrip exercise, brachial artery vasodilation in the old subjects was attenuated compared with that in young subjects following placebo (maximum = ∼3.0 and ∼6.0%, respectively). In contrast to the previously documented attenuation in exercise-induced brachial artery vasodilation in the young group with AOC, in the old subjects the AOC restored vasodilation (maximum = ∼7.0%) to match the young. KE training also improved exercise-induced brachial artery vasodilation. However, in the trained state, AOC administration no longer augmented brachial artery vasodilation in the elderly, but rather attenuated it. These data reveal an age-related pro-/antioxidant imbalance that impacts vascular function and show that exercise training is capable of restoring equilibrium such that vascular function is improved and the AOC-mediated reduction in free radicals now negatively impacts brachial artery vasodilation, as seen in the young. PMID:19966056

The Exercise-Induced Irisin Is Associated with Improved Levels of Glucose Homeostasis Markers in Pregnant Women Participating in 8-Week Prenatal Group Fitness Program: A Pilot Study

PubMed Central

Worska, Aneta; Piernicka, Magdalena; Kortas, Jakub; Jastrzębski, Zbigniew; Radzimiński, Łukasz; Jaworska, Joanna; Micielska, Katarzyna

2017-01-01

Background Both exercise and pregnancy influence serum irisin concentration. Aim To determine how the interaction of pregnancy and exercise affects irisin level and whether various patterns of exercise adherence had different effect on irisin concentration. Methods It was a one-group pretest-posttest study among 9 Caucasian nulliparous healthy women in normal pregnancy (age 23 ± 3 years, 21 ± 2 weeks of gestation; mean ± SD) who participated in 8-week group fitness program. Before and after exercise intervention, we determined serum concentrations of irisin and selected parameters of lipid profile and glucose homeostasis markers. Results In active women, irisin slightly decreased with the development of pregnancy. After 8 weeks of exercising, irisin correlated negatively with fasting glucose (R = −0.922; p = 0.001), glycated hemoglobin (R = −0.784; p = 0.012), and insulin concentrations (R = −0.845; p = 0.004). In women exercising below recommended level, we observed a significant drop in irisin concentration, whereas in women exercising at least three times a week this myokine slightly increased (31% difference; 90% confidence limits ±28; a large, clear effect). Conclusions Irisin stimulated by prenatal exercise may improve glucose homeostasis markers in healthy women and compensate for metabolic changes induced by pregnancy. Moreover, the frequency of exercise may regulate the changes in exercise-induced irisin concentration. PMID:29226153

Induced Electrical Transients Observed in the TALOS-W Adaption Kit

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morgan, G.E.

1959-09-01

An undesirable electrical transient signal had been found to appear in the Mk 5 Mod 0 adaption kit at the time of a TALOS-W missile power changeover. A description of the transient, suggested cause, and cure were discussed.

Transient Anosmia Induces Depressive-like and Anxiolytic-like Behavior and Reduces Amygdalar Corticotropin-Releasing Hormone in a ZnSO4-Induced Mouse Model.

PubMed

Ahn, Sangzin; Choi, Mooseok; Kim, Hyunju; Yang, Eun-Jeong; Mahmood, Usman; Kang, Seong-Il; Shin, Hyun-Woo; Kim, Dae Woo; Kim, Hye-Sun

2018-04-23

Olfactory loss is known to affect both mood and quality of life. Transient anosmia was induced in mice to study the resulting changes in mood, behavior, and on a molecular level. Transient anosmia was induced by a single intranasal instillation of ZnSO4 in BALB/c mice. Hematoxylin and eosin (HE) staining, and potato chip finding test were performed to confirm olfactory loss. Tail suspension, forced swim, and splash tests were performed to evaluate depression-related behavior; while the open field, and elevated plus maze tests were used to evaluate anxiety-related behavior. The mRNA levels of amygdalar corticotropin-releasing hormone (CRH) and hypothalamic glucocorticoid receptor (GR) were quantified using real-time PCR to confirm relevant molecular change. Olfactory loss was confirmed 1-2.5 weeks after induction, and this loss was subsequently reversed over time. The results of the behavioral tests indicated increased depression-like and reduced anxiety-like behavior at week 1. Accordingly, PCR data identified decreased amygdalar CRH expression at week 1. These results suggest that transient anosmia induces both depressive and anxiolytic behavior as a result of decreased amygdalar CRH in a mouse model of anosmia.

Should ovulation be induced in women recovering from an eating disorder or who are compulsive exercisers?

PubMed

Abraham, S; Mira, M; Llewellyn-Jones, D

1990-03-01

The eating and exercise history of women with secondary amenorrhea and failure of ovulation using CC was studied in 14 consecutive women on a GnRH-a program. All had a history of an eating or exercise disorder. At the time of the interview, 7 women continued to have an eating or exercise disorder. There were 15 pregnancies (12 women) with 12 live births, of which 4 weighed less than 2,500 g. Infertility specialists should inquire routinely about a woman's body weight and eating and exercise behaviors, and consider treatment for these before prescribing drugs to induce ovulation.

Exercise and Cardiac Preconditioning Against Ischemia Reperfusion Injury

PubMed Central

Quindry, John C; Hamilton, Karyn L

2013-01-01

Cardiovascular disease (CVD), including ischemia reperfusion (IR) injury, remains a major cause of morbidity and mortality in industrialized nations. Ongoing research is aimed at uncovering therapeutic interventions against IR injury. Regular exercise participation is recognized as an important lifestyle intervention in the prevention and treatment of CVD and IR injury. More recent understanding reveals that moderate intensity aerobic exercise is also an important experimental model for understanding the cellular mechanisms of cardioprotection against IR injury. An important discovery in this regard was the observation that one-to-several days of exercise will attenuate IR injury. This phenomenon has been observed in young and old hearts of both sexes. Due to the short time course of exercise induced protection, IR injury prevention must be mediated by acute biochemical alterations within the myocardium. Research over the last decade reveals that redundant mechanisms account for exercise induced cardioprotection against IR. While much is now known about exercise preconditioning against IR injury, many questions remain. Perhaps most pressing, is what mechanisms mediate cardioprotection in aged hearts and what sex-dependent differences exist. Given that that exercise preconditioning is a polygenic effect, it is likely that multiple mediators of exercise induced cardioprotection have yet to be uncovered. Also unknown, is whether post translational modifications due to exercise are responsible for IR injury prevention. This review will provide an overview the major mechanisms of IR injury and exercise preconditioning. The discussion highlights many promising avenues for further research and describes how exercise preconditioning may continue to be an important scientific paradigm in the translation of cardioprotection research to the clinic. PMID:23909636

Platelet activating factor induces transient blood-brain barrier opening to facilitate edaravone penetration into the brain.

PubMed

Fang, Weirong; Zhang, Rui; Sha, Lan; Lv, Peng; Shang, Erxin; Han, Dan; Wei, Jie; Geng, Xiaohan; Yang, Qichuan; Li, Yunman

2014-03-01

The blood-brain barrier (BBB) greatly limits the efficacy of many neuroprotective drugs' delivery to the brain, so improving drug penetration through the BBB has been an important focus of research. Here we report that platelet activating factor (PAF) transiently opened BBB and facilitated neuroprotectant edaravone penetration into the brain. Intravenous infusion with PAF induced a transient BBB opening in rats, reflected by increased Evans blue leakage and mild edema formation, which ceased within 6 h. Furthermore, rat regional cerebral blood flow (rCBF) declined acutely during PAF infusion, but recovered slowly. More importantly, this transient BBB opening significantly increased the penetration of edaravone into the brain, evidenced by increased edaravone concentrations in tissue interstitial fluid collected by microdialysis and analyzed by Ultra-performance liquid chromatograph combined with a hybrid quadrupole time-of-flight mass spectrometer (UPLC-MS/MS). Similarly, incubation of rat brain microvessel endothelial cells monolayer with 1 μM PAF for 1 h significantly increased monolayer permeability to (125)I-albumin, which recovered 1 h after PAF elimination. However, PAF incubation with rat brain microvessel endothelial cells for 1 h did not cause detectable cytotoxicity, and did not regulate intercellular adhesion molecule-1, matrix-metalloproteinase-9 and P-glycoprotein expression. In conclusion, PAF could induce transient and reversible BBB opening through abrupt rCBF decline, which significantly improved edaravone penetration into the brain. Platelet activating factor (PAF) transiently induces BBB dysfunction and increases BBB permeability, which may be due to vessel contraction and a temporary decline of regional cerebral blood flow (rCBF) triggered by PAF. More importantly, the PAF induced transient BBB opening facilitates neuroprotectant edaravone penetration into brain. The results of this study may provide a new approach to improve drug delivery into the brain. © 2013 International Society for Neurochemistry.

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...

A multi-component parallel-plate flow chamber system for studying the effect of exercise-induced wall shear stress on endothelial cells.

PubMed

Wang, Yan-Xia; Xiang, Cheng; Liu, Bo; Zhu, Yong; Luan, Yong; Liu, Shu-Tian; Qin, Kai-Rong

2016-12-28

In vivo studies have demonstrated that reasonable exercise training can improve endothelial function. To confirm the key role of wall shear stress induced by exercise on endothelial cells, and to understand how wall shear stress affects the structure and the function of endothelial cells, it is crucial to design and fabricate an in vitro multi-component parallel-plate flow chamber system which can closely replicate exercise-induced wall shear stress waveforms in artery. The in vivo wall shear stress waveforms from the common carotid artery of a healthy volunteer in resting and immediately after 30 min acute aerobic cycling exercise were first calculated by measuring the inner diameter and the center-line blood flow velocity with a color Doppler ultrasound. According to the above in vivo wall shear stress waveforms, we designed and fabricated a parallel-plate flow chamber system with appropriate components based on a lumped parameter hemodynamics model. To validate the feasibility of this system, human umbilical vein endothelial cells (HUVECs) line were cultured within the parallel-plate flow chamber under abovementioned two types of wall shear stress waveforms and the intracellular actin microfilaments and nitric oxide (NO) production level were evaluated using fluorescence microscope. Our results show that the trends of resting and exercise-induced wall shear stress waveforms, especially the maximal, minimal and mean wall shear stress as well as oscillatory shear index, generated by the parallel-plate flow chamber system are similar to those acquired from the common carotid artery. In addition, the cellular experiments demonstrate that the actin microfilaments and the production of NO within cells exposed to the two different wall shear stress waveforms exhibit different dynamic behaviors; there are larger numbers of actin microfilaments and higher level NO in cells exposed in exercise-induced wall shear stress condition than resting wall shear stress condition. The parallel-plate flow chamber system can well reproduce wall shear stress waveforms acquired from the common carotid artery in resting and immediately after exercise states. Furthermore, it can be used for studying the endothelial cells responses under resting and exercise-induced wall shear stress environments in vitro.

Central and peripheral cardiovascular responses to electrically induced and voluntary leg exercise

NASA Technical Reports Server (NTRS)

Saltin, B.; Strange, S.; Bangsbo, J.; Kim, C. K.; Duvoisin, M.; Hargens, A.; Gollnick, P. D.

1990-01-01

With long missions in space countermeasures have to be used to secure safe operations in space and a safe return to Earth. Exercises of various forms have been used, but the question has arisen whether electrically induced contractions of muscle especially sensitive to weightlessness and crucial for man's performance would aid in maintaining their optimal function. The physiological responses both to short term and prolonged dynamic exercise performed either voluntarily or induced by electrical stimulation were considered. The local and systemic circulatory responses were similar for the voluntary and electrically induced contractions. The metabolic response was slightly more pronounced with electrical stimulation. This could be a reflection of not only slow twitch (type 1) but also fast twitch (type 2) fibers being recruited when the contractions were induced electrically. Intramuscular pressure recordings indicated that the dominant fraction of the muscle group was engaged regardless of mode of activation. Some 70 percent of the short term peak voluntary exercise capacity could be attained with electrical stimulation. Thus, electrically induced contractions of specific muscle groups should indeed be considered as an efficient countermeasure.

A Comparison of Exercise-Induced Muscle Damage Following Maximal Eccentric Contractions in Men and Boys.

PubMed

Deli, Chariklia K; Fatouros, Ioannis G; Paschalis, Vassilis; Georgakouli, Kalliopi; Zalavras, Athanasios; Avloniti, Alexandra; Koutedakis, Yiannis; Jamurtas, Athanasios Z

2017-08-01

Research regarding exercise-induced muscle-damage mainly focuses on adults. The present study examined exercise-induced muscle-damage responses in adults compared with children. Eleven healthy boys (10-12 y) and 15 healthy men (18-45 y) performed 5 sets of 15 maximal eccentric contractions of the knee extensors. Range of motion (ROM), delayed onset muscle soreness (DOMS) during squat and walking, and peak isometric, concentric and eccentric torque were assessed before, post, 24, 48, 72, and 96 hr postexercise. Creatine kinase (CK) activity was assessed before and 72 hr postexercise. Eccentric exercise resulted in DOMS during squat that persisted for up to 96h in men, and 48 hr in boys (p < .05), and DOMS during walking that persisted for up to 72 hr in men, and 48 hr in boys (p < .01). The ROM was lower in both age groups 48 hr postexercise (p < .001). Isometric (p < .001), concentric (p < .01) and eccentric (p < .01) force decreased post, and up to 48 hr postexercise in men. Except for a reduction in isometric force immediately after exercise, no other changes occurred in boys' isokinetic force. CK activity increased in men at 72 hr postexercise compared with pre exercise levels (p = .05). Our data provide further confirmation that children are less susceptible to exercise-induced muscle damage compared with adults.

Passive smoking reduces and vitamin C increases exercise-induced oxidative stress: does this make passive smoking an anti-oxidant and vitamin C a pro-oxidant stimulus?

PubMed

Theodorou, Anastasios A; Paschalis, Vassilis; Kyparos, Antonios; Panayiotou, George; Nikolaidis, Michalis G

2014-11-07

The current interpretative framework states that, for a certain experimental treatment (usually a chemical substance) to be classified as "anti-oxidant", it must possess the property of reducing (or even nullifying) exercise-induced oxidative stress. The aim of the study was to compare side by side, in the same experimental setup, redox biomarkers responses to an identical acute eccentric exercise session, before and after chronic passive smoking (considered a pro-oxidant stimulus) or vitamin C supplementation (considered an anti-oxidant stimulus). Twenty men were randomly assigned into either passive smoking or vitamin C group. All participants performed two acute eccentric exercise sessions, one before and one after either exposure to passive smoking or vitamin C supplementation for 12 days. Vitamin C, oxidant biomarkers (F2-isoprostanes and protein carbonyls) and the non-enzymatic antioxidant (glutathione) were measured, before and after passive smoking, vitamin C supplementation or exercise. It was found that chronic exposure to passive smoking increased the level of F2-isoprostanes and decreased the level of glutathione at rest, resulting in minimal increase or absence of oxidative stress after exercise. Conversely, chronic supplementation with vitamin C decreased the level of F2-isoprostanes and increased the level of glutathione at rest, resulting in marked exercise-induced oxidative stress. Contrary to the current scientific consensus, our results show that, when a pro-oxidant stimulus is chronically delivered, it is more likely that oxidative stress induced by subsequent exercise is decreased and not increased. Reversely, it is more likely to find greater exercise-induced oxidative stress after previous exposure to an anti-oxidant stimulus. We believe that the proposed framework will be a useful tool to reach more pragmatic explanations of redox biology phenomena. Copyright © 2014 Elsevier Inc. All rights reserved.

Involvement of bradykinin in acute exercise-induced increase of glucose uptake and GLUT-4 translocation in skeletal muscle: studies in normal and diabetic humans and rats.

PubMed

Taguchi, T; Kishikawa, H; Motoshima, H; Sakai, K; Nishiyama, T; Yoshizato, K; Shirakami, A; Toyonaga, T; Shirontani, T; Araki, E; Shichiri, M

2000-07-01

Acute exercise induces glucose uptake in skeletal muscle in vivo, but the molecular mechanism of this phenomenon remains to be identified. In this study, we evaluated the involvement of bradykinin in exercise-induced glucose uptake in humans and rats. In human studies, plasma bradykinin concentrations increased significantly during an ergometer exercise (20 minutes) in 8 healthy normoglycemic subjects and 6 well-controlled type 2 diabetic patients (mean hemoglobin A1c [HbA1c], 6.4% +/- 0.6%), but not in 6 poorly controlled type 2 diabetics (mean HbA1c, 11.6% +/- 2.6%). In rat studies, plasma bradykinin concentrations also significantly increased after 1 hour of swimming in nondiabetic and mildly diabetic (streptozotocin [STZ] 45 mg/kg intravenously [IV]) rats, but not in rats with severe diabetes (STZ 65 mg/kg IV). Glucose influx (maximum velocity [Vmax]) and GLUT-4 translocation in skeletal muscle of nondiabetic rats significantly increased after 1 hour of swimming, but these increases were abrogated by subcutaneous infusion of bradykinin B2 receptor antagonist HOE-140 (400 microg x kg(-1) x d(-1)). Insulin-stimulated tyrosine phosphorylation and phosphatidylinositol (PI) 3-kinase activity in response to insulin injection (20 U/kg IV) in the portal vein were significantly attenuated in exercised rats pretreated with HOE-140 compared with saline-treated exercised rats. Our results suggest that plasma bradykinin concentrations increase in response to acute exercise and this increase is affected by blood glucose status in diabetic patients. Moreover, the exercise-induced increase in bradykinin may be involved in modulating exercise-induced glucose transport through an increase of GLUT-4 translocation, as well as enhancement of the insulin signal pathway, during the postexercise period in skeletal muscle, resulting in a decrease of blood glucose.

One nuclear calcium transient induced by a single burst of action potentials represents the minimum signal strength in activity-dependent transcription in hippocampal neurons.

PubMed

Yu, Yan; Oberlaender, Kristin; Bengtson, C Peter; Bading, Hilmar

2017-07-01

Neurons undergo dramatic changes in their gene expression profiles in response to synaptic stimulation. The coupling of neuronal excitation to gene transcription is well studied and is mediated by signaling pathways activated by cytoplasmic and nuclear calcium transients. Despite this, the minimum synaptic activity required to induce gene expression remains unknown. To address this, we used cultured hippocampal neurons and cellular compartment analysis of temporal activity by fluorescence in situ hybridization (catFISH) that allows detection of nascent transcripts in the cell nucleus. We found that a single burst of action potentials, consisting of 24.4±5.1 action potentials during a 6.7±1.9s depolarization of 19.5±2.0mV causing a 9.3±0.9s somatic calcium transient, is sufficient to activate transcription of the immediate early gene arc (also known as Arg3.1). The total arc mRNA yield produced after a single burst-induced nuclear calcium transient was very small and, compared to unstimulated control neurons, did not lead to a significant increase in arc mRNA levels measured using quantitative reverse transcriptase PCR (qRT-PCR) of cell lysates. Significantly increased arc mRNA levels became detectable in hippocampal neurons that had undergone 5-8 consecutive burst-induced nuclear calcium transients at 0.05-0.15Hz. These results indicate that a single burst-induced nuclear calcium transient can activate gene expression and that transcription is rapidly shut off after synaptic stimulation has ceased. Copyright © 2017 Elsevier Ltd. All rights reserved.

Exercise intensity and oxygen uptake kinetics in African-American and Caucasian women.

PubMed

Lai, Nicola; Tolentino-Silva, Fatima; Nasca, Melita M; Silva, Marco A; Gladden, L Bruce; Cabrera, Marco E

2012-03-01

The effect of exercise intensity on the on- and off-transient kinetics of oxygen uptake (VO(2)) was investigated in African American (AA) and Caucasian (C) women. African American (n = 7) and Caucasian (n = 6) women of similar age, body mass index and weight, performed an incremental test and bouts of square-wave exercise at moderate, heavy and very heavy intensities on a cycle ergometer. Gas exchange threshold (LT(GE)) was lower in AA (13.6 ± 2.3 mL kg(-1) min(-1)) than C (18.6 ± 5.6 mL kg(-1) min(-1)). The dynamic exercise and recovery VO(2) responses were characterized by mathematical models. There were no significant differences in (1) peak oxygen uptake (VO(2peak)) between AA (28.5 ± 5 mL kg(-1) min(-1)) and C (31.1 ± 6.6 mL kg(-1) min(-1)) and (2) VO(2) kinetics at any exercise intensity. At moderate exercise, the on- and off- VO(2) kinetics was described by a monoexponential function with similar time constants τ (1,on) (39.4 ± 12.5; 38.8 ± 15 s) and τ (1,off) (52.7 ± 10.1; 40.7 ± 4.4 s) for AA and C, respectively. At heavy and very heavy exercise, the VO(2) kinetics was described by a double-exponential function. The parameter values for heavy and very heavy exercise in the AA group were, respectively: τ (1,on) (47.0 ± 10.8; 44.3 ± 10 s), τ (2,on) (289 ± 63; 219 ± 90 s), τ (1,off) (45.9 ± 6.2; 50.7 ± 10 s), τ (2,off) (259 ± 120; 243 ± 93 s) while in the C group were, respectively: τ (1,on) (41 ± 12; 43.2 ± 15 s); τ (2, on) (277 ± 81; 215 ± 36 s), τ (1,off) (40.2 ± 3.4; 42.3 ± 7.2 s), τ (2,off) (215 ± 133; 228 ± 64 s). The on- and off-transients were symmetrical with respect to model order and dependent on exercise intensity regardless of race. Despite similar VO(2) kinetics, LT(GE) and gain of the VO(2) on-kinetics at moderate intensity were lower in AA than C. However, generalization to the African American and Caucasian populations is constrained by the small subject numbers.

Mechanisms of Transient Signaling via Short and Long Prolactin Receptor Isoforms in Female and Male Sensory Neurons*

PubMed Central

Belugin, Sergei; Diogenes, Anibal R.; Patil, Mayur J.; Ginsburg, Erika; Henry, Michael A.; Akopian, Armen N.

2013-01-01

Prolactin (PRL) regulates activity of nociceptors and causes hyperalgesia in pain conditions. PRL enhances nociceptive responses by rapidly modulating channels in nociceptors. The molecular mechanisms underlying PRL-induced transient signaling in neurons are not well understood. Here we use a variety of cell biology and pharmacological approaches to show that PRL transiently enhanced capsaicin-evoked responses involve protein kinase C ϵ (PKCϵ) or phosphatidylinositol 3-kinase (PI3K) pathways in female rat trigeminal (TG) neurons. We next reconstituted PRL-induced signaling in a heterologous expression system and TG neurons from PRL receptor (PRLR)-null mutant mice by expressing rat PRLR-long isoform (PRLR-L), PRLR-short isoform (PRLR-S), or a mix of both. Results show that PRLR-S, but not PRLR-L, is capable of mediating PRL-induced transient enhancement of capsaicin responses in both male and female TG neurons. However, co-expression of PRLR-L with PRLR-S (1:1 ratio) leads to the inhibition of the transient PRL actions. Co-expression of PRLR-L deletion mutants with PRLR-S indicated that the cytoplasmic site adjacent to the trans-membrane domain of PRLR-L was responsible for inhibitory effects of PRLR-L. Furthermore, in situ hybridization and immunohistochemistry data indicate that in normal conditions, PRLR-L is expressed mainly in glia with little expression in rat sensory neurons (3–5%) and human nerves. The predominant PRLR form in TG neurons/nerves from rats and humans is PRLR-S. Altogether, PRL-induced transient signaling in sensory neurons is governed by PI3K or PKCϵ, mediated via the PRLR-S isoform, and transient effects mediated by PRLR-S are inhibited by presence of PRLR-L in these cells. PMID:24142695

Mechanisms of transient signaling via short and long prolactin receptor isoforms in female and male sensory neurons.

PubMed

Belugin, Sergei; Diogenes, Anibal R; Patil, Mayur J; Ginsburg, Erika; Henry, Michael A; Akopian, Armen N

2013-11-29

Prolactin (PRL) regulates activity of nociceptors and causes hyperalgesia in pain conditions. PRL enhances nociceptive responses by rapidly modulating channels in nociceptors. The molecular mechanisms underlying PRL-induced transient signaling in neurons are not well understood. Here we use a variety of cell biology and pharmacological approaches to show that PRL transiently enhanced capsaicin-evoked responses involve protein kinase C ε (PKCε) or phosphatidylinositol 3-kinase (PI3K) pathways in female rat trigeminal (TG) neurons. We next reconstituted PRL-induced signaling in a heterologous expression system and TG neurons from PRL receptor (PRLR)-null mutant mice by expressing rat PRLR-long isoform (PRLR-L), PRLR-short isoform (PRLR-S), or a mix of both. Results show that PRLR-S, but not PRLR-L, is capable of mediating PRL-induced transient enhancement of capsaicin responses in both male and female TG neurons. However, co-expression of PRLR-L with PRLR-S (1:1 ratio) leads to the inhibition of the transient PRL actions. Co-expression of PRLR-L deletion mutants with PRLR-S indicated that the cytoplasmic site adjacent to the trans-membrane domain of PRLR-L was responsible for inhibitory effects of PRLR-L. Furthermore, in situ hybridization and immunohistochemistry data indicate that in normal conditions, PRLR-L is expressed mainly in glia with little expression in rat sensory neurons (3-5%) and human nerves. The predominant PRLR form in TG neurons/nerves from rats and humans is PRLR-S. Altogether, PRL-induced transient signaling in sensory neurons is governed by PI3K or PKCε, mediated via the PRLR-S isoform, and transient effects mediated by PRLR-S are inhibited by presence of PRLR-L in these cells.

Lightning induced currents in aircraft wiring using low level injection techniques

NASA Technical Reports Server (NTRS)

Stevens, E. G.; Jordan, D. T.

1991-01-01

Various techniques were studied to predict the transient current induced into aircraft wiring bundles as a result of an aircraft lightning strike. A series of aircraft measurements were carried out together with a theoretical analysis using computer modeling. These tests were applied to various aircraft and also to specially constructed cylinders installed within coaxial return conductor systems. Low level swept frequency CW (carrier waves), low level transient and high level transient injection tests were applied to the aircraft and cylinders. Measurements were made to determine the transfer function between the aircraft drive current and the resulting skin currents and currents induced on the internal wiring. The full threat lightning induced transient currents were extrapolated from the low level data using Fourier transform techniques. The aircraft and cylinders used were constructed from both metallic and CFC (carbon fiber composite) materials. The results show the pulse stretching phenomenon which occurs for CFC materials due to the diffusion of the lightning current through carbon fiber materials. Transmission Line Matrix modeling techniques were used to compare theoretical and measured currents.

FOOD-DEPENDENT EXERCISE-INDUCED ANAPHYLAXIS DUE TO INGESTION OF MIKAN (CITRUS UNSHIU).

PubMed

Tanaka, Yutaka; Sugihara, Marie; Tsumagari, Shuntaro; Takamatsu, Nobue; Kurihara, Kazuyuki

A 12-year-old girl was referred to our hospital owing to repeated anaphylactic reactions induced by exercise after meals. Food-dependent exercise-induced anaphylaxis (FDEIAn) was suspected. However, sequential tests of typical foods, including egg, milk, soy, and wheat, in combination with exercise, were all negative.The results of the skin prick test (SPT) for Citrus unshiu and specific IgE test for orange and grapefruit were positive. Although no symptoms were noted after an exercise challenge combined with the ingestion of only Citrus unshiu, an anaphylactic reaction was induced by additional acetyl-salicylic acid. From these results, she was diagnosed with FDEIAn due to the ingestion of Citrus unshiu. Because the SPT results for other citrus fruits (including orange, grapefruit, lemon, yuzu, sudachi, ponkan, and iyokan) were all positive, it was suggested that these fruits demonstrate cross-reactivity with each other. Since the girl eliminated citrus fruits from her diet, she has not developed any anaphylactic symptoms. Citrus fruits are not known to cause FDEIAn, but the findings of this case suggest that it is necessary to recognize them as a causative allergen of FDEIAn.

Exploring the Mechanisms of Exercise-Induced Hypoalgesia Using Somatosensory and Laser Evoked Potentials

PubMed Central

Jones, Matthew D.; Taylor, Janet L.; Booth, John; Barry, Benjamin K.

2016-01-01

Exercise-induced hypoalgesia is well described, but the underlying mechanisms are unclear. The aim of this study was to examine the effect of exercise on somatosensory evoked potentials, laser evoked potentials, pressure pain thresholds and heat pain thresholds. These were recorded before and after 3-min of isometric elbow flexion exercise at 40% of the participant's maximal voluntary force, or an equivalent period of rest. Exercise-induced hypoalgesia was confirmed in two experiments (Experiment 1–SEPs; Experiment 2–LEPs) by increased pressure pain thresholds at biceps brachii (24.3 and 20.6% increase in Experiment 1 and 2, respectively; both d > 0.84 and p < 0.001) and first dorsal interosseous (18.8 and 21.5% increase in Experiment 1 and 2, respectively; both d > 0.57 and p < 0.001). In contrast, heat pain thresholds were not significantly different after exercise (forearm: 10.8% increase, d = 0.35, p = 0.10; hand: 3.6% increase, d = 0.06, p = 0.74). Contrasting effects of exercise on the amplitude of laser evoked potentials (14.6% decrease, d = −0.42, p = 0.004) and somatosensory evoked potentials (10.9% increase, d = −0.02, p = 1) were also observed, while an equivalent period of rest showed similar habituation (laser evoked potential: 7.3% decrease, d = −0.25, p = 0.14; somatosensory evoked potential: 20.7% decrease, d = −0.32, p = 0.006). The differential response of pressure pain thresholds and heat pain thresholds to exercise is consistent with relative insensitivity of thermal nociception to the acute hypoalgesic effects of exercise. Conflicting effects of exercise on somatosensory evoked potentials and laser evoked potentials were observed. This may reflect non-nociceptive contributions to the somatosensory evoked potential, but could also indicate that peripheral nociceptors contribute to exercise-induced hypoalgesia. PMID:27965587

Temporal characteristics of exercise-induced diaphragmatic fatigue.

PubMed

Archiza, Bruno; Welch, Joseph F; Geary, Caitlin M; Allen, Grayson P; Borghi-Silva, Audrey; Sheel, A William

2018-04-01

There is evidence suggesting diaphragmatic fatigue (DF) occurs relatively early during high-intensity exercise; however, studies investigating the temporal characteristics of exercise-induced DF are limited by incongruent methodology. Eight healthy adult males (25 ± 5 yr) performed a maximal incremental exercise test on a cycle ergometer on day 1. A constant-load time-to-exhaustion (TTE) exercise test was conducted on day 2 at 60% delta between the calculated gas exchange threshold and peak work rate. Two additional constant-load exercise tests were performed at the same intensity on days 3 and 4 in a random order to either 50 or 75% TTE. DF was assessed on days 2, 3, and 4 by measuring transdiaphragmatic twitch pressure (P di,tw ) in response to cervical magnetic stimulation. DF was present after 75 and 100% TTE (≥20% decrease in P di,tw ). The magnitude of fatigue was 15.5 ± 5.7%, 23.6 ± 6.4%, and 35.0 ± 12.1% at 50, 75, and 100% TTE, respectively. Significant differences were found between 100 to 75 and 50% TTE (both P < 0.01), and 75 to 50% TTE ( P < 0.01). There was a significant relationship between the magnitude of fatigue and cumulative diaphragm force output ( r = 0.785; P < 0.001). Ventilation, the mechanical work of breathing (WOB), and pressure-time products were not different between trials ( P > 0.05). Our data indicate that exercise-induced DF presents a relatively late onset and is proportional to the cumulative WOB; thus the ability of the diaphragm to generate pressure progressively declines throughout exercise. NEW & NOTEWORTHY The notion that diaphragmatic fatigue (DF) occurs relatively early during exercise is equivocal. Our results indicate that DF occurs during high-intensity endurance exercise in healthy men and its magnitude is strongly related to the amount of pressure and work generated by respiratory muscles. Thus we conclude that the work of breathing is the major determinant of exercise-induced DF.

Pronounced Effects of Acute Endurance Exercise on Gene Expression in Resting and Exercising Human Skeletal Muscle

PubMed Central

Catoire, Milène; Mensink, Marco; Boekschoten, Mark V.; Hangelbroek, Roland; Müller, Michael; Schrauwen, Patrick; Kersten, Sander

2012-01-01

Regular physical activity positively influences whole body energy metabolism and substrate handling in exercising muscle. While it is recognized that the effects of exercise extend beyond exercising muscle, it is unclear to what extent exercise impacts non-exercising muscles. Here we investigated the effects of an acute endurance exercise bouts on gene expression in exercising and non-exercising human muscle. To that end, 12 male subjects aged 44–56 performed one hour of one-legged cycling at 50% Wmax. Muscle biopsies were taken from the exercising and non-exercising leg before and immediately after exercise and analyzed by microarray. One-legged cycling raised plasma lactate, free fatty acids, cortisol, noradrenalin, and adrenalin levels. Surprisingly, acute endurance exercise not only caused pronounced gene expression changes in exercising muscle but also in non-exercising muscle. In the exercising leg the three most highly induced genes were all part of the NR4A family. Remarkably, many genes induced in non-exercising muscle were PPAR targets or related to PPAR signalling, including PDK4, ANGPTL4 and SLC22A5. Pathway analysis confirmed this finding. In conclusion, our data indicate that acute endurance exercise elicits pronounced changes in gene expression in non-exercising muscle, which are likely mediated by changes in circulating factors such as free fatty acids. The study points to a major influence of exercise beyond the contracting muscle. PMID:23226462

New perspectives concerning feedback influences on cardiorespiratory control during rhythmic exercise and on exercise performance.

PubMed

Dempsey, Jerome A

2012-09-01

The cardioaccelerator and ventilatory responses to rhythmic exercise in the human are commonly viewed as being mediated predominantly via feedforward 'central command' mechanisms, with contributions from locomotor muscle afferents to the sympathetically mediated pressor response. We have assessed the relative contributions of three types of feedback afferents on the cardiorespiratory response to voluntary, rhythmic exercise by inhibiting their normal 'tonic' activity in healthy animals and humans and in chronic heart failure. Transient inhibition of the carotid chemoreceptors during moderate intensity exercise reduced muscle sympathetic nerve activity (MSNA) and increased limb vascular conductance and blood flow; and reducing the normal level of respiratory muscle work during heavier intensity exercise increased limb vascular conductance and blood flow. These cardiorespiratory effects were prevented via ganglionic blockade and were enhanced in chronic heart failure and in hypoxia. Blockade of μ opioid sensitive locomotor muscle afferents, with preservation of central motor output via intrathecal fentanyl: (a) reduced the mean arterial blood pressure (MAP), heart rate and ventilatory responses to all steady state exercise intensities; and (b) during sustained high intensity exercise, reduced O(2) transport, increased central motor output and end-exercise muscle fatigue and reduced endurance performance. We propose that these three afferent reflexes - probably acting in concert with feedforward central command - contribute significantly to preserving O(2) transport to locomotor and to respiratory muscles during exercise. Locomotor muscle afferents also appear to provide feedback concerning the metabolic state of the muscle to influence central motor output, thereby limiting peripheral fatigue development.

Risk stratification for large artery or chronic coronary artery disease-related ischemic stroke in octogenarians undergoing exercise stress myocardial perfusion imaging: A cohort study.

PubMed

Katsikis, Athanasios; Theodorakos, Athanasios; Drosatos, Alexandros; Konstantinou, Konstantinos; Papaioannou, Spyridon; Koutelou, Maria

2017-04-01

To test, if in octogenarians, treadmill exercise with myocardial perfusion imaging (exercise-MPI) can risk stratify for large artery or chronic CAD-related ischemic stroke (LACCIS). Exercise-MPI-related data of 237 octogenarians (55% prior MI or revascularization) without previous stroke were registered and prospective follow-up was performed to document LACCIS. LACCIS was defined as acute onset of neurological symptoms with CT/MRI findings of non-lacunar-type infarcts in the absence of atrial fibrillation or intracardiac embolic sources. After 7.3 years, 10 LACCIS were documented. SSS [HR 1.08 (1.02-1.13 95% CIs), SDS [HR 1.1 (1.04-1.16 95% CIs)], and non-sustained VT or transient AV block during exercise [HR 3.9 (1.7-9.0 95% CIs)] were predictors of LACCIS (P < .01 for all). A SSS threshold of 16 had 81% specificity for identification of future LACCIS and risk groups formed according to this cut-off had significantly different LACCIS-free survival (P = .015). Exercise-MPI in octogenarians can provide risk stratification markers for LACCIS.

Psychobiological mechanisms of exercise dependence.

PubMed

Hamer, Mark; Karageorghis, Costas I

2007-01-01

Exercise dependence (ED) is characterised by an obsessive and unhealthy preoccupation with exercise. Previous research has focused largely on identifying behavioural aspects of ED, although the biological mechanisms remain unknown and are under researched. We review various ED hypotheses including affect regulation, anorexia analogue, sympathetic arousal and beta-endorphin. We also present a novel hypothesis pertaining to ED and interleukin (IL)-6, which combines previous hypotheses with literature from the field of psycho-neuroimmunology. We explore the notion that IL-6 provides a link from the periphery to the brain, which may mediate the underlying features of ED. We propose a conceptual model indicating that, in individuals prone to ED, exercise results in a transient reduction in negative affect, but concurrently results in excessive production of IL-6 and the activation of neuroendocrine pathways, which are associated with behavioural and psychological disturbances of exercise withdrawal. Our intention is for this model to serve as a basis for further research in the area of ED, which may eventually lead to the development of successful treatment strategies. Recent developments in methods to reliably assess these biological markers from blood and saliva samples should encourage such research to be undertaken in exercise settings.

Methamphetamine-induced neurotoxicity disrupts pharmacologically evoked dopamine transients in the dorsomedial and dorsolateral striatum.

PubMed

Robinson, John D; Howard, Christopher D; Pastuzyn, Elissa D; Byers, Diane L; Keefe, Kristen A; Garris, Paul A

2014-08-01

Phasic dopamine (DA) signaling, during which burst firing by DA neurons generates short-lived elevations in extracellular DA in terminal fields called DA transients, is implicated in reinforcement learning. Disrupted phasic DA signaling is proposed to link DA depletions and cognitive-behavioral impairment in methamphetamine (METH)-induced neurotoxicity. Here, we further investigated this disruption by assessing effects of METH pretreatment on DA transients elicited by a drug cocktail of raclopride, a D2 DA receptor antagonist, and nomifensine, an inhibitor of the dopamine transporter (DAT). One advantage of this approach is that pharmacological activation provides a large, high-quality data set of transients elicited by endogenous burst firing of DA neurons for analysis of regional differences and neurotoxicity. These pharmacologically evoked DA transients were measured in the dorsomedial (DM) and dorsolateral (DL) striatum of urethane-anesthetized rats by fast-scan cyclic voltammetry. Electrically evoked DA levels were also recorded to quantify DA release and uptake, and DAT binding was determined by means of autoradiography to index DA denervation. Pharmacologically evoked DA transients in intact animals exhibited a greater amplitude and frequency and shorter duration in the DM compared to the DL striatum, despite similar pre- and post-drug assessments of DA release and uptake in both sub-regions as determined from the electrically evoked DA signals. METH pretreatment reduced transient activity. The most prominent effect of METH pretreatment on transients across striatal sub-region was decreased amplitude, which mirrored decreased DAT binding and was accompanied by decreased DA release. Overall, these results identify marked intrastriatal differences in the activity of DA transients that appear independent of presynaptic mechanisms for DA release and uptake and further support disrupted phasic DA signaling mediated by decreased DA release in rats with METH-induced neurotoxicity.

METHAMPHETAMINE-INDUCED NEUROTOXICITY DISRUPTS PHARMACOLOGICALLY EVOKED DOPAMINE TRANSIENTS IN THE DORSOMEDIAL AND DORSOLATERAL STRIATUM

PubMed Central

Robinson, John D.; Howard, Christopher D.; Pastuzyn, Elissa D.; Byers, Diane L.; Keefe, Kristen A.; Garris, Paul A.

2014-01-01

Phasic dopamine (DA) signaling, during which burst firing by dopamine neurons generates short-lived elevations in extracellular DA in terminal fields called DA transients, is implicated in reinforcement learning. Disrupted phasic DA signaling is proposed to link DA depletions and cognitive-behavioral impairment in methamphetamine (METH)-induced neurotoxicity. Here we further investigated this disruption by assessing effects of METH pretreatment on DA transients elicited by a drug cocktail of raclopride, a D2 DA receptor antagonist, and nomifensine, an inhibitor of the dopamine transporter (DAT). One advantage of this approach is that pharmacological activation provides a large, high-quality data set of transients elicited by endogenous burst firing of DA neurons for analysis of regional differences and neurotoxicity. These pharmacologically evoked DA transients were measured in the dorsomedial (DM) and dorsolateral (DL) striatum of urethane-anesthetized rats by fast-scan cyclic voltammetry. Electrically evoked DA levels were also recorded to quantify DA release and uptake, and DAT binding was determined by autoradiography to index DA denervation. Pharmacologically evoked DA transients in intact animals exhibited a greater amplitude and frequency and shorter duration in the DM compared to the DL striatum, despite similar pre- and post-drug assessments of DA release and uptake in both sub-regions as determined from the electrically evoked DA signals. METH pretreatment reduced transient activity. The most prominent effect of METH pretreatment on transients across striatal sub-region was decreased amplitude, which mirrored decreased DAT binding and was accompanied by decreased DA release. Overall, these results identify marked intrastriatal differences in the activity of DA transients that appear independent of presynaptic mechanisms for DA release and uptake and further support disrupted phasic DA signaling mediated by decreased DA release in rats with METH-induced neurotoxicity. PMID:24562969

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-Induced Bronchospasm

MedlinePlus

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In Healthy Young Men, a Short Exhaustive Exercise Alters the Oxidative Stress Only Slightly, Independent of the Actual Fitness.

PubMed

Finkler, Maya; Hochman, Ayala; Pinchuk, Ilya; Lichtenberg, Dov

2016-01-01

The aim of the present study was to evaluate the apparent disagreement regarding the effect of a typical cycling progressive exercise, commonly used to assess VO2max, on the kinetics of ex vivo copper induced peroxidation of serum lipids. Thirty-two (32) healthy young men, aged 24-30 years, who do not smoke and do not take any food supplements, participated in the study. Blood was withdrawn from each participant at three time points (before the exercise and 5 minutes and one hour after exercise). Copper induced peroxidation of sera made of the blood samples was monitored by spectrophotometry. For comparison, we also assayed TBARS concentration and the activity of oxidation-related enzymes. The physical exercise resulted in a slight and reversible increase of TBARS and slight changes in the activities of the studied antioxidant enzymes and the lag preceding peroxidation did not change substantially. Most altered parameters returned to baseline level one hour after exercise. Notably, the exercise-induced changes in OS did not correlate with the physical fitness of the subjects, as evaluated in this study (VO2max = 30-60 mL/min/kg). We conclude that in healthy young fit men a short exhaustive exercise alters only slightly the OS, independent of the actual physical fitness.

Inflammatory modulation of exercise salience: using hormesis to return to a healthy lifestyle

PubMed Central

2010-01-01

Most of the human population in the western world has access to unlimited calories and leads an increasingly sedentary lifestyle. The propensity to undertake voluntary exercise or indulge in spontaneous physical exercise, which might be termed "exercise salience", is drawing increased scientific attention. Despite its genetic aspects, this complex behaviour is clearly modulated by the environment and influenced by physiological states. Inflammation is often overlooked as one of these conditions even though it is known to induce a state of reduced mobility. Chronic subclinical inflammation is associated with the metabolic syndrome; a largely lifestyle-induced disease which can lead to decreased exercise salience. The result is a vicious cycle that increases oxidative stress and reduces metabolic flexibility and perpetuates the disease state. In contrast, hormetic stimuli can induce an anti-inflammatory phenotype, thereby enhancing exercise salience, leading to greater biological fitness and improved functional longevity. One general consequence of hormesis is upregulation of mitochondrial function and resistance to oxidative stress. Examples of hormetic factors include calorie restriction, extreme environmental temperatures, physical activity and polyphenols. The hormetic modulation of inflammation, and thus, exercise salience, may help to explain the highly heterogeneous expression of voluntary exercise behaviour and therefore body composition phenotypes of humans living in similar obesogenic environments. PMID:21143891

Inhibition of Glutathione Synthesis Induced by Exhaustive Running Exercise via the Decreased Influx Rate of L-Cysteine in Rat Erythrocytes.

PubMed

Xiong, Yanlian; Xiong, Yanlei; Zhou, Shuai; Yu, Zhenhai; Zhao, Dongmei; Wang, Zhiqiang; Li, Yuling; Yan, Jingtong; Cai, Yu; Zhang, Wenqian

2016-01-01

The main purpose of this study was to investigate the effect of exhaustive exercise on L-cysteine uptake and its effect on erythrocyte glutathione (GSH) synthesis and metabolism. Rats were divided into three groups: sedentary control (C), exhaustive running exercise (ERE) and moderate running exercise (MRE) (n=12 rats/group). We determined the L-cysteine efflux and influx in vitro in rat erythrocytes and its relationship with GSH synthesis. Total anti-oxidant potential of plasma was measured in terms of the ferric reducing ability of plasma (FRAP) values for each exercise group. In addition, the glucose metabolism enzyme activity of erythrocytes was also measured under in vitro incubation conditions. Biochemical studies confirmed that exhaustive running exercise significantly increased oxidative damage parameters in thiobarbituric acid reactive substances (TBARS) and methemoglobin levels. Pearson correlation analysis suggested that L-cysteine influx was positively correlated with erythrocyte GSH synthesis and FRAP values in both the control and exercise groups. In vitro oxidation incubation significantly decreased the level of glucose metabolism enzyme activity in the control group. We presented evidence of the exhaustive exercise-induced inhibition of GSH synthesis due to a dysfunction in L-cysteine transport. In addition, oxidative stress-induced changes in glucose metabolism were the driving force underlying decreased L-cysteine uptake in the exhaustive exercise group. © 2016 The Author(s) Published by S. Karger AG, Basel.

The TreadWheel: Interval Training Protocol for Gently Induced Exercise in Drosophila melanogaster.

PubMed

Lowman, Kelsey E; Wyatt, Brélahn J; Cunneely, Owen P; Reed, Laura K

2018-06-08

The incidence of complex metabolic diseases has increased as a result of a widespread transition towards lifestyles of increased caloric intake and lowered activity levels. These multifactorial diseases arise from a combination of genetic, environmental, and behavioral factors. One such complex disease is Metabolic Syndrome (MetS), which is a cluster of metabolic disorders, including hypertension, hyperglycemia, and abdominal obesity. Exercise and dietary intervention are the primary treatments recommended by doctors to mitigate obesity and its subsequent metabolic diseases. Exercise intervention, in particular aerobic interval training, stimulates favorable changes in the common risk factors for Type 2 Diabetes Mellitus (T2DM), Cardiovascular Disease (CVD), and other conditions. With the influx of evidence describing the therapeutic effect exercise has on metabolic health, establishing a system that models exercise in a controlled setting provides a valuable tool for assessing the effects of exercise in an experimental context. Drosophila melanogaster is a great tool for investigating the physiological and molecular changes that result from exercise intervention. The flies have short lifespans and similar mechanisms of metabolizing nutrients when compared to humans. To induce exercise in Drosophila, we developed a machine called the TreadWheel, which utilizes the fly's innate, negative geotaxis tendency to gently induce climbing. This enables researchers to perform experiments on large cohorts of genetically diverse flies to better understand the genotype-by-environment interactions underlying the effects of exercise on metabolic health.

Oxygen uptake kinetics of constant-load work - Upright vs. supine exercise

NASA Technical Reports Server (NTRS)

Convertino, V. A.; Goldwater, D. J.; Sandler, H.

1984-01-01

Supine and upright positions were used in a comparitive study of the effects of constant load exercise on oxygen uptake (VO2), O2 deficit, steady-state VO2 and VO2 following recovery from constant load work. Ten male subjects (36-40 yr.) performed one submaximal exercise test in the supine and one test in the upright position consisting of 5 min rest and 5 min cycle ergometer exercise at 700 kg/min followed by ten minutes of recovery. It is found that the significant difference in VO2 kinetics during exercise in the upright compared to supine position resulted from changes in oxygen transport and utilization mechanisms rather than changes in mechanical efficiency. To the extent that data measured in the supine position can be used to estimate physiological responses to zero gravity, it is suggested that limitation of systemic O2 consumption may be the result of slow rates of oxygen uptake during transient periods of muscular work. Significant reductions in the rate of steady-state VO2 attainment at submaximal work intensities may produce an onset of muscle fatigue and exhaustion.

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.

Thermoregulatory responses in exercising rats: methodological aspects and relevance to human physiology.

PubMed

Wanner, Samuel Penna; Prímola-Gomes, Thales Nicolau; Pires, Washington; Guimarães, Juliana Bohnen; Hudson, Alexandre Sérvulo Ribeiro; Kunstetter, Ana Cançado; Fonseca, Cletiana Gonçalves; Drummond, Lucas Rios; Damasceno, William Coutinho; Teixeira-Coelho, Francisco

2015-01-01

Rats are used worldwide in experiments that aim to investigate the physiological responses induced by a physical exercise session. Changes in body temperature regulation, which may affect both the performance and the health of exercising rats, are evident among these physiological responses. Despite the universal use of rats in biomedical research involving exercise, investigators often overlook important methodological issues that hamper the accurate measurement of clear thermoregulatory responses. Moreover, much debate exists regarding whether the outcome of rat experiments can be extrapolated to human physiology, including thermal physiology. Herein, we described the impact of different exercise intensities, durations and protocols and environmental conditions on running-induced thermoregulatory changes. We focused on treadmill running because this type of exercise allows for precise control of the exercise intensity and the measurement of autonomic thermoeffectors associated with heat production and loss. Some methodological issues regarding rat experiments, such as the sites for body temperature measurements and the time of day at which experiments are performed, were also discussed. In addition, we analyzed the influence of a high body surface area-to-mass ratio and limited evaporative cooling on the exercise-induced thermoregulatory responses of running rats and then compared these responses in rats to those observed in humans. Collectively, the data presented in this review represent a reference source for investigators interested in studying exercise thermoregulation in rats. In addition, the present data indicate that the thermoregulatory responses of exercising rats can be extrapolated, with some important limitations, to human thermal physiology.

Effect of different exercise protocols on metabolic profiles and fatty acid metabolism in skeletal muscle in high-fat diet-fed rats.

PubMed

Shen, Youqing; Xu, Xiangfeng; Yue, Kai; Xu, Guodong

2015-05-01

To evaluate the efficacy of mild-intensity endurance, high-intensity interval, and concurrent exercise on preventing high-fat diet-induced obesity. Male rats were divided into five groups, control diet/sedentary group, high-fat diet/sedentary, high-fat diet/endurance exercise, high-fat diet/interval exercise (HI), and high-fat diet/concurrent exercise. All exercise groups were made to exercise for 10 weeks, with matched running distances. Body weight, fat content, blood metabolites, quantitative insulin sensitivity check index (QUICKI), and adipocyte and liver lipid droplet size were assessed, and the expression of fatty acid metabolism-related genes was quantified. All exercise protocols reduced body weight, adiposity, serum triglycerides, and fasting glucose and also improved QUICKI to some extent. However, only HI prevented obesity and its associated pathologies completely. The expression of stearoyl-coenzyme A desaturase-1 was elevated in all rats fed a high-fat diet whereas carnitine palmitoyltransferase 1 (CPT1) expression was increased with exercise. Rev-erbα expression was elevated only in the HI group, which also had the highest level of CPT1 expression. The HI-induced increase in Rev-erbα and CPT1 expression was associated with the complete prevention of diet-induced obesity. Moreover, the increased caloric expenditure achieved with this protocol was preferential over other exercise regimens, and might be used to improve lipid metabolism. © 2015 The Obesity Society.

Lack of desensitization of the cough reflex in ovalbumin-sensitized rabbits during exercise.

PubMed

Tiotiu, Angelica; Chenuel, Bruno; Foucaud, Laurent; Demoulin, Bruno; Demoulin-Alexikova, Silvia; Christov, Christo; Poussel, Mathias

2017-01-01

Cough is a major symptom of asthma frequently experienced during exercise but little is known about interactions between cough and exercise. The goal of our study was to clarify the potential modulation of the cough reflex (CR) by exercise in a spontaneously breathing anaesthetized animal model of airway eosinophilic inflammation. Ten ovalbumin (OVA) sensitized adult rabbits and 8 controls were studied. The ventilatory response to direct tracheal stimulation, performed both at rest and during exercise was determined to quantify the incidence and the sensitivity of the CR. Broncho-alveolar lavages (BAL) and cell counts were performed to assess the level of the airway inflammation following OVA-induced sensitization. Exercise was mimicked by Electrically induced hindlimb Muscular Contractions (EMC). Among 494 tracheal stimulations, 261 were performed at rest and 233 at exercise. OVA challenges in sensitized rabbits caused a significant increase in the percentage of eosinophils (p = 0.008) in BAL. EMC increased minute ventilation by 36% and 35% in OVA and control rabbits respectively, compared to rest values. The sensitivity of the CR decreased during exercise compared to baseline in control rabbits (p = 0.0313) while it remained unchanged in OVA rabbits. The desensitization of the CR during exercise in control rabbits was abolished in OVA rabbits. The precise role of airway inflammation in this lack of CR desensitization needs to be further investigated but it might contribute to the exercise-induced cough in asthmatics.

Thermoregulatory responses in exercising rats: methodological aspects and relevance to human physiology

PubMed Central

Wanner, Samuel Penna; Prímola-Gomes, Thales Nicolau; Pires, Washington; Guimarães, Juliana Bohnen; Hudson, Alexandre Sérvulo Ribeiro; Kunstetter, Ana Cançado; Fonseca, Cletiana Gonçalves; Drummond, Lucas Rios; Damasceno, William Coutinho; Teixeira-Coelho, Francisco

2015-01-01

Rats are used worldwide in experiments that aim to investigate the physiological responses induced by a physical exercise session. Changes in body temperature regulation, which may affect both the performance and the health of exercising rats, are evident among these physiological responses. Despite the universal use of rats in biomedical research involving exercise, investigators often overlook important methodological issues that hamper the accurate measurement of clear thermoregulatory responses. Moreover, much debate exists regarding whether the outcome of rat experiments can be extrapolated to human physiology, including thermal physiology. Herein, we described the impact of different exercise intensities, durations and protocols and environmental conditions on running-induced thermoregulatory changes. We focused on treadmill running because this type of exercise allows for precise control of the exercise intensity and the measurement of autonomic thermoeffectors associated with heat production and loss. Some methodological issues regarding rat experiments, such as the sites for body temperature measurements and the time of day at which experiments are performed, were also discussed. In addition, we analyzed the influence of a high body surface area-to-mass ratio and limited evaporative cooling on the exercise-induced thermoregulatory responses of running rats and then compared these responses in rats to those observed in humans. Collectively, the data presented in this review represent a reference source for investigators interested in studying exercise thermoregulation in rats. In addition, the present data indicate that the thermoregulatory responses of exercising rats can be extrapolated, with some important limitations, to human thermal physiology. PMID:27227066

Tumor vessel normalization after aerobic exercise enhances chemotherapeutic efficacy.

PubMed

Schadler, Keri L; Thomas, Nicholas J; Galie, Peter A; Bhang, Dong Ha; Roby, Kerry C; Addai, Prince; Till, Jacob E; Sturgeon, Kathleen; Zaslavsky, Alexander; Chen, Christopher S; Ryeom, Sandra

2016-10-04

Targeted therapies aimed at tumor vasculature are utilized in combination with chemotherapy to improve drug delivery and efficacy after tumor vascular normalization. Tumor vessels are highly disorganized with disrupted blood flow impeding drug delivery to cancer cells. Although pharmacologic anti-angiogenic therapy can remodel and normalize tumor vessels, there is a limited window of efficacy and these drugs are associated with severe side effects necessitating alternatives for vascular normalization. Recently, moderate aerobic exercise has been shown to induce vascular normalization in mouse models. Here, we provide a mechanistic explanation for the tumor vascular normalization induced by exercise. Shear stress, the mechanical stimuli exerted on endothelial cells by blood flow, modulates vascular integrity. Increasing vascular shear stress through aerobic exercise can alter and remodel blood vessels in normal tissues. Our data in mouse models indicate that activation of calcineurin-NFAT-TSP1 signaling in endothelial cells plays a critical role in exercise-induced shear stress mediated tumor vessel remodeling. We show that moderate aerobic exercise with chemotherapy caused a significantly greater decrease in tumor growth than chemotherapy alone through improved chemotherapy delivery after tumor vascular normalization. Our work suggests that the vascular normalizing effects of aerobic exercise can be an effective chemotherapy adjuvant.

Exercise Prevents Cardiac Injury and Improves Mitochondrial Biogenesis in Advanced Diabetic Cardiomyopathy with PGC-1α and Akt Activation.

PubMed

Wang, Hui; Bei, Yihua; Lu, Yan; Sun, Wei; Liu, Qi; Wang, Yalong; Cao, Yujie; Chen, Ping; Xiao, Junjie; Kong, Xiangqing

2015-01-01

Diabetic cardiomyopathy (DCM) represents the major cause of morbidity and mortality among diabetics. Exercise has been reported to be effective to protect the heart from cardiac injury during the development of DCM. However, the potential cardioprotective effect of exercise in advanced DCM remains unclear. Seven-week old male C57BL/6 wild-type or db/db mice were either subjected to a running exercise program for 15 weeks or kept sedentary. Cardiac function, myocardial apoptosis and fibrosis, and mitochondrial biogenesis were examined for evaluation of cardiac injury. A reduction in ejection fraction and fractional shortening in db/db mice was significantly reversed by exercise training. DCM induced remarkable cardiomyocyte apoptosis and increased ratio of Bax/Bcl-2 at the protein level. Meanwhile, DCM caused slightly myocardial fibrosis with elevated mRNA levels of collagen I and collagen III. Also, DCM resulted in a reduction of mitochondrial DNA (mtDNA) replication and transcription, together with reduced mtDNA content and impaired mitochondrial ultrastructure. All of these changes could be abolished by exercise training. Furthermore, DCM-associated inhibition of PGC-1α and Akt signaling was significantly activated by exercise, indicating that exercise-induced activation of PGC-1α and Akt signaling might be responsible for mediating cardioprotective effect of exercise in DCM. Exercise preserves cardiac function, prevents myocardial apoptosis and fibrosis, and improves mitochondrial biogenesis in the late stage of DCM. Exercise-induced activation of PGC-1α and Akt signaling might be promising therapeutic targets for advanced DCM. © 2015 S. Karger AG, Basel.

Acute exhaustive rowing exercise reduces skin microvascular dilator function in young adult rowing athletes.

PubMed

Stupin, Marko; Stupin, Ana; Rasic, Lidija; Cosic, Anita; Kolar, Luka; Seric, Vatroslav; Lenasi, Helena; Izakovic, Kresimir; Drenjancevic, Ines

2018-02-01

The effect of acute exhaustive exercise session on skin microvascular reactivity was assessed in professional rowers and sedentary subjects. A potential involvement of altered hemodynamic parameters and/or oxidative stress level in the regulation of skin microvascular blood flow by acute exercise were determined. Anthropometric, biochemical, and hemodynamic parameters were measured in 18 young healthy sedentary men and 20 professional rowers who underwent a single acute exercise session. Post-occlusive reactive hyperemia (PORH), endothelium-dependent acetylcholine (ACh), and endothelium-independent sodium nitroprusside (SNP) microvascular responses were assessed by laser Doppler flowmetry in skin microcirculation before and after acute exercise. Serum lipid peroxidation products and plasma antioxidant capacity were measured using spectrophotometry. At baseline, rowers had significantly lower diastolic blood pressure (DBP) and heart rate (HR), and higher stroke volume (SV), PORH, and endothelium-dependent vasodilation than sedentary. Acute exercise caused a significant increase in systolic blood pressure, DBP, HR, and SV and a decrease in total peripheral resistance in both groups. Acute exercise induced a significant impairment in PORH and ACh-induced response in rowers, but not in sedentary, whereas the SNP-induced vasodilation was not affected by acute exercise in any group. Antioxidant capacity significantly increased only in sedentary after acute exercise. Single acute exercise session impaired microvascular reactivity and endothelial function in rowers but not in sedentary, possibly due to (1) more rowing grades and higher exercise intensity achieved by rowers; (2) a higher increase in arterial pressure in rowers than in sedentary men; and (3) a lower antioxidant capacity in rowers.

Black tea high-molecular-weight polyphenol stimulates exercise training-induced improvement of endurance capacity in mouse via the link between AMPK and GLUT4.

PubMed

Eguchi, Tomoaki; Kumagai, Chiaki; Fujihara, Takashi; Takemasa, Thoru; Ozawa, Tetsuo; Numata, Osamu

2013-01-01

Aerobic exercise can promote "fast-to-slow transition" in skeletal muscles, i.e. an increase in oxidative fibers, mitochondria, and myoglobin and improvement in glucose and lipid metabolism. Here, we found that mice administered Mitochondria Activation Factor (MAF) combined with exercise training could run longer distances and for a longer time compared with the exercise only group; MAF is a high-molecular-weight polyphenol purified from black tea. Furthermore, MAF intake combined with exercise training increased phosphorylation of AMPK and mRNA level of glucose transporter 4 (GLUT4). Thus, our data demonstrate for the first time that MAF activates exercise training-induced intracellular signaling pathways that involve AMPK, and improves endurance capacity.

Repeated high-intensity interval exercise shortens the positive effect on executive function during post-exercise recovery in healthy young males.

PubMed

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

2016-06-01

A single bout of aerobic exercise improves executive function (EF), but only for a short period. Compared with a single bout of aerobic exercise, we recently found that high-intensity interval exercise (HIIE) could maintain a longer improvement in EF. However, the mechanism underlying the effect of different exercise modes on the modifications of EF remains unclear. The purpose of the current investigation was to test our hypothesis that the amount of exercise-induced lactate production and its accumulation affects human brain function during and after exercise, thereby affecting post-exercise EF. Ten healthy male subjects performed cycle ergometer exercise. The HIIE protocol consisted of four 4-min bouts at 90% peak VO2 with a 3-min active recovery period at 60% peak VO2. The amount of lactate produced during exercise was manipulated by repeating the HIIE twice with a resting period of 60min between the 1st HIIE and 2nd HIIE. To evaluate EF, a color-word Stroop task was performed, and reverse-Stroop interference scores were obtained. EF immediately after the 1st HIIE was significantly improved compared to that before exercise, and the improved EF was sustained during 40min of the post-exercise recovery. However, for the 2nd HIIE, the improved EF was sustained for only 10min of the post-exercise recovery period, despite the performance of the same exercise. In addition, during and following HIIE, the glucose and lactate accumulation induced by the 2nd HIIE was significantly lower than that induced by the 1st HIIE. Furthermore, there was an inverse relationship between lactate and EF by plotting the changes in lactate levels against changes in EF from pre-exercise during the late phase of post-exercise recovery. These findings suggested the possibility that repeated bouts of HIIE, which decreases lactate accumulation, may dampen the positive effect of exercise on EF during the post-exercise recovery. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Preliminary Results for the OECD/NEA Time Dependent Benchmark using Rattlesnake, Rattlesnake-IQS and TDKENO

DOE Office of Scientific and Technical Information (OSTI.GOV)

DeHart, Mark D.; Mausolff, Zander; Weems, Zach

2016-08-01

One goal of the MAMMOTH M&S project is to validate the analysis capabilities within MAMMOTH. Historical data has shown limited value for validation of full three-dimensional (3D) multi-physics methods. Initial analysis considered the TREAT startup minimum critical core and one of the startup transient tests. At present, validation is focusing on measurements taken during the M8CAL test calibration series. These exercises will valuable in preliminary assessment of the ability of MAMMOTH to perform coupled multi-physics calculations; calculations performed to date are being used to validate the neutron transport solver Rattlesnake\\cite{Rattlesnake} and the fuels performance code BISON. Other validation projects outsidemore » of TREAT are available for single-physics benchmarking. Because the transient solution capability of Rattlesnake is one of the key attributes that makes it unique for TREAT transient simulations, validation of the transient solution of Rattlesnake using other time dependent kinetics benchmarks has considerable value. The Nuclear Energy Agency (NEA) of the Organization for Economic Cooperation and Development (OECD) has recently developed a computational benchmark for transient simulations. This benchmark considered both two-dimensional (2D) and 3D configurations for a total number of 26 different transients. All are negative reactivity insertions, typically returning to the critical state after some time.« less

Absolute versus relative intensity of physical activity in a dose-response context.

PubMed

Shephard, R J

2001-06-01

To examine the importance of relative versus absolute intensities of physical activity in the context of population health. A standard computer-search of the literature was supplemented by review of extensive personal files. Consensus reports (Category D Evidence) have commonly recommended moderate rather than hard physical activity in the context of population health. Much of the available literature provides Category C Evidence. It has often confounded issues of relative intensity with absolute intensity or total weekly dose of exercise. In terms of cardiovascular health, there is some evidence for a threshold intensity of effort, perhaps as high as 6 METs, in addition to a minimum volume of physical activity. Decreases in blood pressure and prevention of stroke seem best achieved by moderate rather than high relative intensities of physical activity. Many aspects of metabolic health depend on the total volume of activity; moderate relative intensities of effort are more effective in mobilizing body fat, but harder relative intensities may help to increase energy expenditures postexercise. Hard relative intensities seem needed to augment bone density, but this may reflect an associated increase in volume of activity. Hard relative intensities of exercise induce a transient immunosuppression. The optimal intensity of effort, relative or absolute, for protection against various types of cancer remains unresolved. Acute effects of exercise on mood state also require further study; long-term benefits seem associated with a moderate rather than a hard relative intensity of effort. The importance of relative versus absolute intensity of effort depends on the desired health outcome, and many issues remain to be resolved. Progress will depend on more precise epidemiological methods of assessing energy expenditures and studies that equate total energy expenditures between differing relative intensities. There is a need to focus on gains in quality-adjusted life expectancy.

The Effects of Acute Dopamine Precursor Depletion on the Reinforcing Value of Exercise in Anorexia Nervosa.

PubMed

O'Hara, Caitlin B; Keyes, Alexandra; Renwick, Bethany; Leyton, Marco; Campbell, Iain C; Schmidt, Ulrike

2016-01-01

This study investigated whether dopaminergic systems are involved in the motivation to engage in behaviours associated with anorexia nervosa (AN), specifically, the drive to exercise. Women recovered from AN (AN REC, n = 17) and healthy controls (HC, n = 15) were recruited. The acute phenylalanine/tyrosine depletion (APTD) method was used to transiently decrease dopamine synthesis and transmission. The effect of dopamine precursor depletion on drive to exercise was measured using a progressive ratio (PR) exercise breakpoint task. Both groups worked for the opportunity to exercise, and, at baseline, PR breakpoint scores were higher in AN REC than HC. Compared to values on the experimental control session, APTD did not decrease PR breakpoint scores in AN REC, but significantly decreased scores in HC. These data show that women recovered from AN are more motivated to exercise than HC, although in both groups, activity is more reinforcing than inactivity. Importantly, decreasing dopamine does not reduce the motivation to exercise in people recovered from AN, but in contrast, does so in HC. It is proposed that in AN, drive to exercise develops into a behaviour that is largely independent of dopamine mediated reward processes and becomes dependent on cortico-striatal neurocircuitry that regulates automated, habit- or compulsive-like behaviours. These data strengthen the case for the involvement of reward, learning, habit, and dopaminergic systems in the aetiology of AN.

Effect of aerobic exercise on hunger feelings and satiety regulating hormones in obese teenage girls.

PubMed

Prado, Wagner L; Balagopal, P Babu; Lofrano-Prado, Mara C; Oyama, Lila M; Tenório, Thiago Ricardo; Botero, João Paulo; Hill, James O

2014-11-01

Exercise is implicated in modifying subsequent energy intake (EI) through alterations in hunger and/or satiety hormones. Our aim was to examine the effects of aerobic exercise on hunger, satiety regulatory peptides, and EI in obese adolescents. Nine obese girls (age: 13-18 years old, BMI: 33.74 ± 4.04 kg/m2) participated in this randomized controlled crossover study. Each participant randomly underwent 2 experimental protocols: control (seated for 150 min) and exercise (exercised for 30 min on a treadmill performed at ventilatory threshold [VT] intensity and then remained seated for 120 min). Leptin, peptide YY(3-36) (PYY(3-36)), and subjective hunger were measured at baseline as well as 30 min and 150 min, followed by 24-hr EI measurement. Exercise session resulted in an acute increase in PYY(3-36) (p < .01) without changes in leptin and/or hunger scores. The control session increased hunger scores (p < .01) and decreased circulating leptin levels (p = .03). There was a strong effect size for carbohydrate intake (d = 2.14) and a modest effect size for protein intake (d = 0.61) after the exercise compared with the control session. Exercise performed at VT intensity in this study appears to provoke a state of transient anorexia in obese girls. These changes may be linked to an increase in circulating PYY3-36 and maintenance of leptin levels.

Immediate effect of exercise on achilles tendon properties: systematic review.

PubMed

Obst, Steven J; Barrett, Rod S; Newsham-West, Richard

2013-08-01

Understanding the mechanical and morphological adaptation of the Achilles tendon (AT) in response to acute exercise could have important implications for athletic performance, injury prevention, and rehabilitation. The purpose of this study was to conduct a systematic review and critical evaluation of the literature to determine the immediate effect of a single bout of exercise on the mechanical and morphological properties of the AT in vivo. Five electronic research databases were systematically searched for intervention-based studies reporting mechanical and morphological properties of the AT after a single bout of exercise. Searches revealed 3292 possible articles; 21 met the inclusion criteria. There is evidence that maximal isometric contractions and prolonged static stretching (>5 min) of the triceps surae complex cause an immediate decrease in AT stiffness, whereas prolonged running and hopping have minimal effect. Limited but consistent evidence exists, indicating that AT hysteresis is reduced after prolonged static stretching. Consistent evidence supports a reduction in free AT diameter (anterior-posterior) after dynamic ankle exercise, and this change appears most pronounced in the healthy tendon and after eccentric exercise. The mechanical and morphological properties of the AT in vivo are affected by acute exercise in a mode- and dose-dependent manner. Transient changes in AT stiffness, hysteresis, and diameter after unaccustomed exercise modes and doses may expose the tendon to increased risk of strain injury and impact on the mechanical function of the triceps surae muscle-tendon unit.

The Effects of Acute Dopamine Precursor Depletion on the Reinforcing Value of Exercise in Anorexia Nervosa

PubMed Central

O’Hara, Caitlin B.; Keyes, Alexandra; Renwick, Bethany; Leyton, Marco; Campbell, Iain C.; Schmidt, Ulrike

2016-01-01

This study investigated whether dopaminergic systems are involved in the motivation to engage in behaviours associated with anorexia nervosa (AN), specifically, the drive to exercise. Women recovered from AN (AN REC, n = 17) and healthy controls (HC, n = 15) were recruited. The acute phenylalanine/tyrosine depletion (APTD) method was used to transiently decrease dopamine synthesis and transmission. The effect of dopamine precursor depletion on drive to exercise was measured using a progressive ratio (PR) exercise breakpoint task. Both groups worked for the opportunity to exercise, and, at baseline, PR breakpoint scores were higher in AN REC than HC. Compared to values on the experimental control session, APTD did not decrease PR breakpoint scores in AN REC, but significantly decreased scores in HC. These data show that women recovered from AN are more motivated to exercise than HC, although in both groups, activity is more reinforcing than inactivity. Importantly, decreasing dopamine does not reduce the motivation to exercise in people recovered from AN, but in contrast, does so in HC. It is proposed that in AN, drive to exercise develops into a behaviour that is largely independent of dopamine mediated reward processes and becomes dependent on cortico-striatal neurocircuitry that regulates automated, habit- or compulsive-like behaviours. These data strengthen the case for the involvement of reward, learning, habit, and dopaminergic systems in the aetiology of AN. PMID:26808920

Ingestion of an Amino Acid Electrolyte Beverage during Resistance Exercise Does Not Impact Fluid Shifts into Muscle or Performance

PubMed Central

Smith, JohnEric W.; Krings, Ben M.; Peterson, Timothy J.; Rountree, Jaden A.; Zak, Roksana B.; McAllister, Matthew J.

2017-01-01

The purpose of this study was to investigate the impact of ingesting an amino acid-electrolyte (AAE) beverage during upper body resistance exercise on transient muscle hypertrophy, exercise performance, markers of muscle damage, and recovery. Participants (n = 15) performed three sets of six repetitions—bench press, lat pull down, incline press, and seated row—followed by three sets of eight repetitions at 75% of the estimated 1 repetition maximum—triceps kickback, hammer curl, triceps push down, and preacher curl—with 90 s of rest between sets. The final set of the push down/preacher curl was performed to failure. Prior to and immediately post-exercise, as well as 24, 48, and 72 h post exercise, cross-sectional muscle thickness was measured. Blood samples were collected prior to exercise, as well as 24, 48, and 72 h post-exercise for serum creatine kinase (CK) analysis. No treatment effect was found for muscle cross-sectional area, repetitions to failure, or serum CK. A main effect (p < 0.001) was observed in the change in serum CK levels in the days following the resistance exercise session. The findings of this study suggest that the acute ingestion of a AAE beverage does not alter acute muscle thickness, performance, perceived soreness and weakness, or markers of muscle damage.

Eating meals before wheel-running exercise attenuate high fat diet-driven obesity in mice under two meals per day schedule.

PubMed

Sasaki, Hiroyuki; Hattori, Yuta; Ikeda, Yuko; Kamagata, Mayo; Shibata, Shigenobu

2015-06-01

Mice that exercise after meals gain less body weight and visceral fat compared to those that exercised before meals under a one meal/exercise time per day schedule. Humans generally eat two or three meals per day, and rarely have only one meal. To extend our previous observations, we examined here whether a "two meals, two exercise sessions per day" schedule was optimal in terms of maintaining a healthy body weight. In this experiment, "morning" refers to the beginning of the active phase (the "morning" for nocturnal animals). We found that 2-h feeding before 2-h exercise in the morning and evening (F-Ex/F-Ex) resulted in greater attenuation of high fat diet (HFD)-induced weight gain compared to other combinations of feeding and exercise under two daily meals and two daily exercise periods. There were no significant differences in total food intake and total wheel counts, but feeding before exercise in the morning groups (F-Ex/F-Ex and F-Ex/Ex-F) increased the morning wheel counts. These results suggest that habitual exercise after feeding in the morning and evening is more effective for preventing HFD-induced weight gain. We also determined whether there were any correlations between food intake, wheel rotation, visceral fat volume and skeletal muscle volumes. We found positive associations between gastrocnemius muscle volumes and morning wheel counts, as well as negative associations between morning food intake volumes/body weight and morning wheel counts. These results suggest that morning exercise-induced increase of muscle volume may refer to anti-obesity. Evening exercise is negatively associated with fat volume increases, suggesting that this practice may counteract fat deposition. Our multifactorial analysis revealed that morning food intake helps to increase exercise, and that evening exercise reduced fat volumes. Thus, exercise in the morning or evening is important for preventing the onset of obesity.

Preventive and therapeutic effect of treadmill running on chronic stress-induced memory deficit in rats.

PubMed

Radahmadi, Maryam; Alaei, Hojjatallah; Sharifi, Mohammad Reza; Hosseini, Nasrin

2015-04-01

Previous results indicated that stress impairs learning and memory. In this research, the effects of preventive, therapeutic and regular continually running activity on chronic stress-induced memory deficit in rats were investigated. 70 male rats were randomly divided into seven groups as follows: Control, Sham, Stress-Rest, Rest-Stress, Stress-Exercise, Exercise-Stress and Exercise-Stress & Exercise groups. Chronic restraint stress was applied 6 h/day for 21days and treadmill running 1 h/day. Memory function was evaluated by the passive avoidance test. The results revealed that running activities had therapeutic effect on mid and long-term memory deficit and preventive effects on short and mid-term memory deficit in stressed rats. Regular continually running activity improved mid and long-term memory compared to Exercise-Stress group. The beneficial effects of exercise were time-dependent in stress conditions. Finally, data corresponded to the possibility that treadmill running had a more important role on treatment rather than on prevention on memory impairment induced by stress. Copyright © 2014 Elsevier Ltd. All rights reserved.

A Role for Exercise in Attenuating Unhealthy Food Consumption in Response to Stress

PubMed Central

Leow, Shina; Jackson, Ben; Alderson, Jacqueline A.; Guelfi, Kym J.; Dimmock, James A.

2018-01-01

It is well established that both acute and chronic stress can be detrimental to health and wellbeing by directly increasing the risk of several chronic diseases and related health problems. In addition, stress may contribute to ill-health indirectly via its downstream effects on individuals’ health-related behaviour, such as promoting the intake of unhealthy palatable foods high in fat and sugar content. This paper reviews (a) the research literature on stress-models; (b) recent research investigating stress-induced eating and (c) the potential physiological and psychological pathways contributing to stress-induced eating. Particular attention is given to (d) the role of physical exercise in attenuating acute stress, with exploration of potential mechanisms through which exercise may reduce unhealthy food and drink consumption subsequent to stressor exposure. Finally, exercise motivation is discussed as an important psychological influence over the capacity for physical exercise to attenuate unhealthy food and drink consumption after exposure to stressors. This paper aims to provide a better understanding of how physical exercise might alleviate stress-induced unhealthy food choices. PMID:29415424

A Role for Exercise in Attenuating Unhealthy Food Consumption in Response to Stress.

PubMed

Leow, Shina; Jackson, Ben; Alderson, Jacqueline A; Guelfi, Kym J; Dimmock, James A

2018-02-06

It is well established that both acute and chronic stress can be detrimental to health and wellbeing by directly increasing the risk of several chronic diseases and related health problems. In addition, stress may contribute to ill-health indirectly via its downstream effects on individuals' health-related behaviour, such as promoting the intake of unhealthy palatable foods high in fat and sugar content. This paper reviews (a) the research literature on stress-models; (b) recent research investigating stress-induced eating and (c) the potential physiological and psychological pathways contributing to stress-induced eating. Particular attention is given to (d) the role of physical exercise in attenuating acute stress, with exploration of potential mechanisms through which exercise may reduce unhealthy food and drink consumption subsequent to stressor exposure. Finally, exercise motivation is discussed as an important psychological influence over the capacity for physical exercise to attenuate unhealthy food and drink consumption after exposure to stressors. This paper aims to provide a better understanding of how physical exercise might alleviate stress-induced unhealthy food choices.

Mechanisms of force depression caused by different types of physical exercise studied by direct electrical stimulation of human quadriceps muscle.

PubMed

Skurvydas, Albertas; Mamkus, Gediminas; Kamandulis, Sigitas; Dudoniene, Vilma; Valanciene, Dovile; Westerblad, Håkan

2016-12-01

Force production frequently remains depressed for several hours or even days after various types of strenuous physical exercise. We hypothesized that the pattern of force changes during the first hour after exercise can be used to reveal muscular mechanisms likely to underlie the decline in muscle performance during exercise as well as factors involved in the triggering the prolonged force depression after exercise. Nine groups of recreationally active male volunteers performed one of the following types of exercise: single prolonged or repeated short maximum voluntary contractions (MVCs); single or repeated all-out cycling bouts; repeated drop jumps. The isometric force of the right quadriceps muscle was measured during stimulation with brief 20 and 100 Hz trains of electrical pulses given before and at regular intervals for 60 min after exercise. All exercises resulted in a prolonged force depression, which was more marked at 20 Hz than at 100 Hz. Short-lasting (≤2 min) MVC and all-out cycling exercises showed an initial force recovery (peak after ~ 5 min) followed by a secondary force depression. The repeated drop jumps, which involve eccentric contractions, resulted in a stable force depression with the 20 Hz force being markedly more decreased after 100 than 10 jumps. In accordance with our hypothesis, the results propose at least three different mechanisms that influence force production after exercise: (1) a transiently recovering process followed by (2) a prolonged force depression after metabolically demanding exercise, and (3) a stable force depression after mechanically demanding contractions.

Exercise training improves function of circulating angiogenic cells in patients with chronic heart failure.

PubMed

Van Craenenbroeck, Emeline M; Hoymans, Vicky Y; Beckers, Paul J; Possemiers, Nadine M; Wuyts, Kurt; Paelinck, Bernard P; Vrints, Christiaan J; Conraads, Viviane M

2010-09-01

Alterations in circulating angiogenic cells (CAC) and endothelial progenitor cells (EPC), known to contribute to endothelial repair, could explain the reversal of endothelial function in response to exercise training. Moreover, training-induced vascular remodeling might affect the acute response of EPC and CAC following a single exercise bout. We studied the impact of exercise training on CAC function and numbers of CD34(+)/KDR(+) EPC in patients with chronic heart failure (CHF) and we assessed the effect of acute exercise on CAC and EPC in sedentary and trained patients. Twenty-one sedentary CHF patients underwent 6-month exercise training and were compared to a non-trained control group (n = 17) and 10 healthy age-matched subjects. At baseline and follow-up, flow-mediated dilation was assessed and graded exercise testing (GXT) was performed. Before and immediately after GXT, CAC migratory capacity was assessed in vitro and circulating CD34(+)/KDR(+) EPC were quantified using flow cytometry. At baseline, CAC migration was significantly impaired in sedentary CHF patients but normalized acutely after GXT. Training corrected endothelial dysfunction, which coincided with a 77% increase in CAC migration (P = 0.0001). Moreover, the GXT-induced improvement detected at baseline was no longer observed after training. Numbers of CD34(+)/KDR(+) EPC increased following 6-month exercise training (P = 0.021), but were not affected by GXT, either prior or post-training. In conclusion, the present findings demonstrate for the first time that exercise training in CHF reverses CAC dysfunction and increases numbers of CD34(+)/KDR(+) EPC, which is accompanied by improvement of peripheral endothelial function. The acute exercise-induced changes in CAC function wane with exercise training, suggesting that repetitive exercise bouts progressively lead to functional endothelial repair.

Left ventricular dyssynchrony in patients with normal ventricular systolic function referred for exercise echocardiography.

PubMed

Bernheim, Alain M; Nakajima, Yoshie; Pellikka, Patricia A

2008-10-01

Exercise testing is often normal despite the presence of exertional symptoms. We hypothesized that left ventricular (LV) dyssynchrony might occur in some patients in the absence of ischemia, LV dysfunction, or wide QRS, and might contribute to exertional symptoms and diminished exercise capacity. Echocardiographic parameters were assessed before and with exercise in 40 patients (age 62 +/- 8 years, 27 with exertional symptoms). All had normal clinically indicated exercise echocardiograms and narrow QRS. The time to peak systolic velocity (Ts) was measured in 12 segments to calculate the standard deviation (Ts-SD) and the maximal difference (Ts-diff). At rest, 25 patients (63%) had dyssynchrony by Ts-SD. With exercise, mean Ts-SD did not increase significantly (34.9 +/- 19.3 ms vs 39.5 +/- 27.2 ms, P = .28). However, Ts-SD increased by greater than 40% in 15 patients (37.5%), remained stable in 19 patients (47.5%), and decreased by greater than 40% in 6 patients (15%). Similar responses were observed for Ts-diff. Patients with exercise-induced dyssynchrony were not more likely to have symptoms. Exercise capacity was inversely correlated with resting Ts-SD (r = -0.37, P = .02) and resting Ts-diff (r = -0.38, P = .02), but not with exercise-induced changes in dyssynchrony. Patients with resting dyssynchrony had higher resting heart rate (73 +/- 12 vs 63 +/- 11 beats/min, P = .02). LV dyssynchrony may occur more frequently than previously thought and may develop with exercise in the absence of ischemia. Exercise-induced LV dyssynchrony was not related to exertional symptoms or exercise capacity. Patients with dyssynchrony at rest had a higher resting heart rate and achieved a lower workload; this may indicate early myocardial impairment.

Excessive exercise habits of runners as new signs of hypertension and arrhythmia.

PubMed

Kim, Young-Joo; Kim, Chul-Hyun; Park, Kyoung-Min

2016-08-15

Excessive exercise may induce arrhythmia, and this risk is higher in middle-aged people. The study aim was to compare the exercise characteristics of middle-aged runners participating in excessive endurance exercise. The subjects of this study were 552 runners (mean age; 49.0±7.4years) without structural heart disease who performed exercise at least twice per week, had consistently exercised for at least three years, and had finished at least five marathons. The arrhythmia runner group (ARG, n=14) and normal runner group (NRG, n=538) were compared with regard to hemodynamic response, cardiorespiratory fitness level, training history, number of finished races, finishing times, and exercise habits. The mean resting systolic (134.0±15.8mmHg) and diastolic (85.8±10.9mmHg) blood pressure values indicated pre-hypertension, while the mean maximal SBP (213.7±27.4mmHg) values indicated exercise-induced hypertension. The VO2max was significantly higher and the maximal DBP was significantly lower in the ARG than in the NRG (p<0.05). Training history was significantly longer in the ARG than in the NRG (p<0.05), while the number of finished marathons, the finishing times in marathons and the exercise frequency per week didn't differ significantly between the two groups. Exercise intensity was significantly higher in the ARG than in the NRG (p<0.01). Middle-aged long-distance runners showed pre-hypertension and exercise-induced hypertension, and the ARG had higher VO2max values, greater exercise intensities, and longer training histories than the NRG. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Effects of Methane-Rich Saline on the Capability of One-Time Exhaustive Exercise in Male SD Rats

PubMed Central

Xin, Lei; Sun, Xuejun; Lou, Shujie

2016-01-01

Purpose To explore the effects of methane-rich saline (CH4 saline) on the capability of one-time exhaustive exercise in male SD rats. Methods Thirty rats were equally divided into to three groups at random: control group (C), placebo group (P) and methane saline group (M). Rats in M group underwent intraperitoneal injection of CH4 saline, and the other two groups simultaneously underwent intraperitoneal injection of normal saline. Then, the exercise capability of rats was tested through one-time exhaustive treadmill exercise except C group. Exercise time and body weight were recorded before and after one-time exhaustive exercise. After exhaustive exercise, the blood and gastrocnemius samples were collected from all rats to detect biochemical parameters in different methods. Results It was found that the treadmill running time was significantly longer in rats treated with CH4 saline. At the same time, CH4 saline reduced the elevation of LD and UN in blood caused by one-time exhaustive exercise. The low level of blood glucose induced by exhaustive exercise was also normalized by CH4 saline. Also CH4 saline lowered the level of CK in plasma. Furthermore, this research indicated that CH4 saline markedly increased the volume of T-AOC in plasma and alleviated the peak of TNF-α in both plasma and gastrocnemius. From H&E staining, CH4 saline effectively improved exercise-induced structural damage in gastrocnemius. Conclusions CH4 saline could enhance exercise capacity in male SD rats through increase of glucose aerobic oxidation, improvement of metabolic clearance and decrease of exhaustive exercise-induced gastrocnemius injury. PMID:26942576

Influence of artistic gymnastics on iron nutritional status and exercise-induced hemolysis in female athletes.

PubMed

Sureira, Thaiz Mattos; Amancio, Olga Silverio; Pellegrini Braga, Josefina Aparecida

2012-08-01

This study evaluates the relationship between body iron losses and gains in artistic gymnastics female athletes. It shows that despite the low iron intake and exercise-induced hemolysis, iron deficiency or iron-deficiency anemia does not occur, but partial changes in the hematological profile do. The hypothesis that gymnasts' nutritional behavior contributes to anemia, which may be aggravated by exercise-induced hemolysis, led to this cross-sectional study, conducted with 43 female artistic gymnasts 6-16 yr old. The control group was formed by 40 nontraining girls, paired by age. Hemogram, serum iron, ferritin, soluble transferrin receptor, haptoglobin, total and fractional bilirubin, Type I urine, and parasitologic and occult fecal blood tests were evaluated. The athletes presented mean hematimetric and serum iron values (p = .020) higher than those of the control group. The bilirubin result discarded any hemolytic alteration in both groups. The haptoglobin results were lower in the athlete group (p = .002), confirming the incidence of exercise-induced hemolysis. Both groups presented low iron intake. The results suggest that artistic gymnastics practice leads to exercise-induced hemolysis and partially changes the hematological profile, although not causing iron deficiency or iron-deficiency anemia, even in the presence of low iron intake.

Exercise-induced rhabdomyolysis - a patient series.

PubMed

Tazmini, Kiarash; Schreiner, Christoffer; Bruserud, Sidsel; Raastad, Truls; Solberg, Erik Ekker

2017-11-14

No guidelines are available for the treatment and follow up of exercise-induced rhabdomyolysis. The purpose of this study was to describe the treatment, complications and follow-up of patients with exercise-induced rhabdomyolysis at Diakonhjemmet Hospital. A retrospective observational study from 2011 up to and including 2015 of patients with exercise-induced rhabdomyolysis ≥ 18 years and with creatine kinase > 5 000 IU/l. We registered a total of 42 patients and obtained informed consent from 31. Twenty were treated as inpatients with a median hospitalisation time of 2.5 (1–6) days. Median creatine kinase was 36 797 (17 172–53 548) IU/l upon admission and 16 051 (11 845–26 505) IU/l at discharge. Median intravenous fluid volume was 6 000 (1 000–27 700) ml. Eleven patients underwent urinary alkalinisation. None developed severe kidney injury or other serious complications such as electrolyte imbalance, compartment syndrome or disseminated intravascular coagulation, either during hospitalisation or in the course of the study period. Healthy persons with exercise-induced rhabdomyolysis have a very low risk of complications. Our patients are treated as outpatients or considered for discharge with creatine kinase < 40 000 IU/l measured at least three days after their workout, and if they have no risk factors or other complications.

Pregnancy-associated transient osteoporosis of the hip: results of a case-control study.

PubMed

Hadji, Peyman; Boekhoff, Jelena; Hahn, Melitta; Hellmeyer, Lars; Hars, Olaf; Kyvernitakis, Ioannis

2017-12-01

The etiology and underlying mechanisms of transient of osteoporosis of the hip (TOH) during pregnancy are still unclear, since no systematic analyses exist. Our results support the hypothesis that TOH is a multifactorial disease, which is associated with immobility, dental problems, and lack of exercise in childhood. Pregnancy-associated transient osteoporosis of the hip (TOH) is a rare but severe form of osteoporosis, which may affect a subgroup of women in the last trimester of pregnancy or immediately postpartum. Common symptoms include acute pain of the hip(s) due to bone marrow edema or even hip fractures. The exact underlining mechanisms of this disorder are still unknown since no published systematic analyses exist. Out of a total of 52 TOH patients, 33 TOH patients could be matched with 33 healthy controls according to age, region, and gravity. The aim of this retrospective case-control study was to evaluate the risk factors for TOH in a homogenous population of women. The baseline characteristics of the two study groups were similar. Overall, 12.1% of the TOH patients sustained a hip fracture. Expectedly, 90.9% of the TOH patients complained about pain of the hip (p ≤ 0.001). TOH patients suffered more frequently from severe dental problems during childhood (p = 0.023) and performed less often sports before and after puberty (p ≤ 0.001), whereas the frequency of immobilization during pregnancy was threefold higher compared to the control group (p = 0.007). We found a significant increase of the TOH risk in patients with dental problems in childhood (OR 3.7; CI 1.3-10.7) as well as in patients with lack of exercise during childhood (OR 4.2; CI 1.3-12.9). Our results support the hypothesis that pregnancy-associated TOH is a multifactorial disease, to which several individual factors may contribute. Hereby, we found significant associations with immobility, dental problems, and lack of exercise in childhood.

Unraveling the Primary Isomerization Dynamics in Cyanobacterial Phytochrome Cph1 with Multi-pulse Manipulations.

PubMed

Kim, Peter W; Rockwell, Nathan C; Freer, Lucy H; Chang, Che-Wei; Martin, Shelley S; Lagarias, J Clark; Larsen, Delmar S

2013-07-20

The ultrafast mechanisms underlying the initial photoisomerization (P r → Lumi-R) in the forward reaction of the cyanobacterial photoreceptor Cph1 were explored with multipulse pump-dump-probe transient spectroscopy. A recently postulated multi-population model was used to fit the transient pump-dump-probe and dump-induced depletion signals. We observed dump-induced depletion of the Lumi-R photoproduct, demonstrating that photoisomerization occurs via evolution on both the excited- and ground-state electronic surfaces. Excited-state equilibrium was not observed, as shown via the absence of a dump-induced excited-state "Le Châtelier redistribution" of excited-state populations. The importance of incorporating the inhomogeneous dynamics of Cph1 in interpreting measured transient data is discussed.

Unraveling the Primary Isomerization Dynamics in Cyanobacterial Phytochrome Cph1 with Multi-pulse Manipulations

PubMed Central

Kim, Peter W.; Rockwell, Nathan C.; Freer, Lucy H.; Chang, Che-Wei; Martin, Shelley S.; Lagarias, J. Clark; Larsen, Delmar S.

2013-01-01

The ultrafast mechanisms underlying the initial photoisomerization (Pr → Lumi-R) in the forward reaction of the cyanobacterial photoreceptor Cph1 were explored with multipulse pump-dump-probe transient spectroscopy. A recently postulated multi-population model was used to fit the transient pump-dump-probe and dump-induced depletion signals. We observed dump-induced depletion of the Lumi-R photoproduct, demonstrating that photoisomerization occurs via evolution on both the excited- and ground-state electronic surfaces. Excited-state equilibrium was not observed, as shown via the absence of a dump-induced excited-state “Le Châtelier redistribution” of excited-state populations. The importance of incorporating the inhomogeneous dynamics of Cph1 in interpreting measured transient data is discussed. PMID:24143267

Effects of caffeine on the inflammatory response induced by a 15-km run competition.

PubMed

Tauler, Pedro; Martínez, Sonia; Moreno, Carlos; Monjo, Marta; Martínez, Pau; Aguiló, Antoni

2013-07-01

The objective of this study is as follows: 1) to determine the effects of caffeine supplementation on the inflammatory response (IL-6 and IL-10 levels and leukocyte numbers) induced by a 15-km run competition and 2) to examine the effect of caffeine supplementation on the energetic metabolites as well as on the exercise-induced oxidative stress. A double-blinded study of supplementation with caffeine was performed. Athletes participating in the study (n = 33) completed a 15-km run competition. Before competition, athletes took 6 mg · kg(-1) body weight of caffeine (caffeine group, n = 17) or a placebo (placebo group, n = 16). Blood samples were taken before and after competition (immediately and after 2-h recovery). Leukocyte numbers were determined in blood. Concentrations of oxidative stress markers, antioxidants, interleukins (IL-6 and IL-10), caffeine, adrenaline, and energetic metabolites were measured in plasma or serum. Caffeine supplementation induced higher increases in circulating total leukocytes and neutrophils, with significant differences between groups after recovery. Adrenaline, glucose, and lactate levels increased after exercise, with higher increases in the caffeine group. Exercise induced significant increases in IL-6 and IL-10 plasma levels, with higher increases in the caffeine group. Caffeine supplementation induced higher increases in oxidative stress markers after the competition. Caffeine supplementation induced higher levels of IL-6 and IL-10 in response to exercise, enhancing the anti-inflammatory response. The caffeine-induced increase in adrenaline could be responsible for the higher increase in IL-6 levels, as well as for the increased lactate levels. Furthermore, caffeine seems to enhance oxidative stress induced by exercise.

Moderate physical exercise induces the oxidation of human blood protein thiols.

PubMed

Inayama, Takayo; Oka, Jun; Kashiba, Misato; Saito, Makoto; Higuchi, Mitsuru; Umegaki, Keizo; Yamamoto, Yorihiro; Matsuda, Mitsuo

2002-03-15

Exercise is known to induce the oxidation of blood low-molecular-weight (LMW) thiols such as reduced glutathione (GSH). We previously reported that full-marathon running induced a decrease in human plasma levels of protein-bound sulfhydryl groups (p-SHs). Moderate exercise, a 30-min running at the intensity of the individual ventilatory threshold, performed by untrained healthy females caused a significant decrease in erythrocyte levels of p-SHs (mostly hemoglobin cysteine residues) and LMW thiols, but their levels returned to each baseline by 2 h. No significant change in plasma LMW thiols was observed. However, plasma levels of p-SHs significantly decreased after running and remained unchanged after 24 h. These results suggest that moderate exercise causes the oxidation of blood thiols, especially protein-bound thiols.

Radon inhalation protects against transient global cerebral ischemic injury in gerbils.

PubMed

Kataoka, Takahiro; Etani, Reo; Takata, Yuji; Nishiyama, Yuichi; Kawabe, Atsushi; Kumashiro, Masayuki; Taguchi, Takehito; Yamaoka, Kiyonori

2014-10-01

Although brain disorders are not the main indication for radon therapy, our previous study suggested that radon inhalation therapy might mitigate brain disorders. In this study, we assessed whether radon inhalation protects against transient global cerebral ischemic injury in gerbils. Gerbils were treated with inhaled radon at a concentration of 2,000 Bq/m(3) for 24 h. After radon inhalation, transient global cerebral ischemia was induced by bilateral occlusion of the common carotid artery. Results showed that transient global cerebral ischemia induced neuronal damage in hippocampal CA1, and the number of damaged neurons was significantly increased compared with control. However, radon treatment inhibited ischemic damage. Superoxide dismutase (SOD) activity in the radon-treated gerbil brain was significantly higher than that in sham-operated gerbils. These findings suggested that radon inhalation activates antioxidative function, especially SOD, thereby inhibiting transient global cerebral ischemic injury in gerbils.

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)

AT1 and aldosterone receptors blockade prevents the chronic effect of nandrolone on the exercise-induced cardioprotection in perfused rat heart subjected to ischemia and reperfusion.

PubMed

Marques-Neto, Silvio Rodrigues; Ferraz, Emanuelle Baptista; Rodrigues, Deivid Carvalho; Njaine, Brian; Rondinelli, Edson; Campos de Carvalho, Antônio Carlos; Nascimento, Jose Hamilton Matheus

2014-04-01

Myocardial tolerance to ischaemia/reperfusion (I/R) injury is improved by exercise training, but this cardioprotection is impaired by the chronic use of anabolic androgenic steroids (AAS). The present study evaluated whether blockade of angiotensin II receptor (AT1-R) with losartan and aldosterone receptor (mineralocorticoid receptor, MR) with spironolactone could prevent the deleterious effect of AAS on the exercise-induced cardioprotection. Male Wistar rats were exercised and treated with either vehicle, nandrolone decanoate (10 mg/kg/week i.m.) or the same dose of nandrolone plus losartan or spironolactone (20 mg/kg/day orally) for 8 weeks. Langendorff-perfused hearts were subjected to I/R and evaluated for the postischaemic recovery of left ventricle (LV) function and infarct size. mRNA and protein expression of angiotensin II type 1 receptor (AT1-R), mineralocorticoid receptor (MR), and KATP channels were determined by reverse-transcriptase polymerase chain reaction and Western blotting. Postischaemic recovery of LV function was better and infarct size was smaller in the exercised rat hearts than in the sedentary rat hearts. Nandrolone impaired the exercise-induced cardioprotection, but this effect was prevented by losartan (AT1-R antagonist) and spironolactone (MR antagonist) treatments. Myocardial AT1-R and MR expression levels were increased, and the expression of the KATP channel subunits SUR2a and Kir6.1 was decreased and Kir6.2 increased in the nandrolone-treated rat hearts. The nandrolone-induced changes of AT1-R, MR, and KATP subunits expression was normalized by the losartan and spironolactone treatments. The chronic nandrolone treatment impairs the exercise-induced cardioprotection against ischaemia/reperfusion injury by activating the cardiac renin-angiotensin-aldosterone system and downregulating KATP channel expression.

Time-course effects of aerobic physical training in the prevention of cigarette smoke-induced COPD.

PubMed

Toledo-Arruda, Alessandra C; Vieira, Rodolfo P; Guarnier, Flávia A; Suehiro, Camila L; Caleman-Neto, Agostinho; Olivo, Clarice R; Arantes, Petra M M; Almeida, Francine M; Lopes, Fernanda D T Q S; Ramos, Ercy M C; Cecchini, Rubens; Lin, Chin Jia; Martins, Milton Arruda

2017-09-01

A previous study by our group showed that regular exercise training (ET) attenuated pulmonary injury in an experimental model of chronic exposure to cigarette smoke (CS) in mice, but the time-course effects of the mechanisms involved in this protection remain poorly understood. We evaluated the temporal effects of regular ET in an experimental model of chronic CS exposure. Male C57BL/6 mice were divided into four groups: Control (sedentary + air), Exercise (aerobic training + air), Smoke (sedentary + smoke), and Smoke + Exercise (aerobic training + smoke). Mice were exposed to CS and ET for 4, 8, or 12 wk. Exercise protected mice exposed to CS from emphysema and reductions in tissue damping and tissue elastance after 12 wk ( P < 0.01). The total number of inflammatory cells in the bronchoalveolar lavage increased in the Smoke group, mainly due to the recruitment of macrophages after 4 wk, neutrophils and lymphocytes after 8 wk, and lymphocytes and macrophages after 12 wk ( P < 0.01). Exercise attenuated this increase in mice exposed to CS. The protection conferred by exercise was mainly observed after exercise adaptation. Exercise increased IL-6 and IL-10 in the quadriceps and lungs ( P < 0.05) after 12 wk. Total antioxidant capacity and SOD was increased and TNF-α and oxidants decreased in lungs of mice exposed to CS after 12 wk ( P < 0.05). The protective effects of exercise against lung injury induced by cigarette smoke exposure suggests that anti-inflammatory mediators and antioxidant enzymes play important roles in chronic obstructive pulmonary disease development mainly after the exercise adaptation. NEW & NOTEWORTHY These experiments investigated for the first time the temporal effects of regular moderate exercise training in cigarette smoke-induced chronic obstructive pulmonary disease. We demonstrate that aerobic conditioning had a protective effect in emphysema development induced by cigarette smoke exposure. This effect was most likely secondary to an effect of exercise on oxidant-antioxidant balance and anti-inflammatory mediators. Copyright © 2017 the American Physiological Society.

The effect of exercise frequency on neuropathic pain and pain-related cellular reactions in the spinal cord and midbrain in a rat sciatic nerve injury model

PubMed Central

Sumizono, Megumi; Otsuka, Shotaro; Terashi, Takuto; Nakanishi, Kazuki; Ueda, Koki; Takada, Seiya; Kikuchi, Kiyoshi

2018-01-01

Background Exercise regimens are established methods that can relieve neuropathic pain. However, the relationship between frequency and intensity of exercise and multiple cellular responses of exercise-induced alleviation of neuropathic pain is still unclear. We examined the influence of exercise frequency on neuropathic pain and the intracellular responses in a sciatic nerve chronic constriction injury (CCI) model. Materials and methods Rats were assigned to four groups as follows: CCI and high-frequency exercise (HFE group), CCI and low-frequency exercise (LFE group), CCI and no exercise (No-Ex group), and naive animals (control group). Rats ran on a treadmill, at a speed of 20 m/min, for 30 min, for 5 (HFE) or 3 (LFE) days a week, for a total of 5 weeks. The 50% withdrawal threshold was evaluated for mechanical sensitivity. The activation of glial cells (microglia and astrocytes), expression of brain-derived neurotrophic factor (BDNF) and μ-opioid receptor in the spinal dorsal horn and endogenous opioid in the midbrain were examined using immunohistochemistry. Opioid receptor antagonists (naloxone) were administered using intraperitoneal injection. Results The development of neuropathic pain was related to the activation of glial cells, increased BDNF expression, and downregulation of the μ-opioid receptor in the ipsilateral spinal dorsal horn. In the No-Ex group, neuropathic pain showed the highest level of mechanical hypersensitivity at 2 weeks, which improved slightly until 5 weeks after CCI. In both exercise groups, the alleviation of neuropathic pain was accelerated through the regulation of glial activation, BDNF expression, and the endogenous opioid system. The expression of BDNF and endogenous opioid in relation to exercise-induced alleviation of neuropathic pain differed in the HFE and LFE groups. The effects of exercise-induced alleviation of mechanical hypersensitivity were reversed by the administration of naloxone. Conclusion The LFE and HFE program reduced neuropathic pain. Our findings indicated that aerobic exercise-induced alleviated neuropathic pain through the regulation of glial cell activation, expression of BDNF in the ipsilateral spinal dorsal horn, and the endogenous opioid system. PMID:29445295

Impact of oxidative stress on exercising skeletal muscle.

PubMed

Steinbacher, Peter; Eckl, Peter

2015-04-10

It is well established that muscle contractions during exercise lead to elevated levels of reactive oxygen species (ROS) in skeletal muscle. These highly reactive molecules have many deleterious effects, such as a reduction of force generation and increased muscle atrophy. Since the discovery of exercise-induced oxidative stress several decades ago, evidence has accumulated that ROS produced during exercise also have positive effects by influencing cellular processes that lead to increased expression of antioxidants. These molecules are particularly elevated in regularly exercising muscle to prevent the negative effects of ROS by neutralizing the free radicals. In addition, ROS also seem to be involved in the exercise-induced adaptation of the muscle phenotype. This review provides an overview of the evidences to date on the effects of ROS in exercising muscle. These aspects include the sources of ROS, their positive and negative cellular effects, the role of antioxidants, and the present evidence on ROS-dependent adaptations of muscle cells in response to physical exercise.

Why do individuals not lose more weight from an exercise intervention at a defined dose? An energy balance analysis

PubMed Central

Thomas, D. M.; Bouchard, C.; Church, T.; Slentz, C.; Kraus, W. E.; Redman, L. M.; Martin, C. K.; Silva, A. M.; Vossen, M.; Westerterp, K.; Heymsfield, S. B.

2013-01-01

Summary Weight loss resulting from an exercise intervention tends to be lower than predicted. Modest weight loss can arise from an increase in energy intake, physiological reductions in resting energy expenditure, an increase in lean tissue or a decrease in non-exercise activity. Lower than expected, weight loss could also arise from weak and invalidated assumptions within predictive models. To investigate these causes, we systematically reviewed studies that monitored compliance to exercise prescriptions and measured exercise-induced change in body composition. Changed body energy stores were calculated to determine the deficit between total daily energy intake and energy expenditures. This information combined with available measurements was used to critically evaluate explanations for low exercise-induced weight loss. We conclude that the small magnitude of weight loss observed from the majority of evaluated exercise interventions is primarily due to low doses of prescribed exercise energy expenditures compounded by a concomitant increase in caloric intake. PMID:22681398

Voluntary exercise and increased food intake after mild chronic stress improve social avoidance behavior in mice.

PubMed

Otsuka, Airi; Shiuchi, Tetsuya; Chikahisa, Sachiko; Shimizu, Noriyuki; Séi, Hiroyoshi

2015-11-01

It is well-established that exercise can influence psychological conditions, cognitive function, and energy metabolism in peripheral tissues including the skeletal muscle. However, it is not clear whether exercise can influence social interaction with others and alleviate defeat stress. This study investigated the effect of voluntary wheel running on impaired social interaction induced by chronic social defeat stress (SDS) using the resident-intruder social defeat model. Mice were divided into three groups: control, stress alone, and stress+exercise. SDS was performed by exposing C57BL/6 mice to retired ICR mice for 2.5 min. The C57BL/6 mice were continuously defeated by these resident (aggressor) mice and, following 5 days of SDS, experienced 2 days of rest with no SDS. Mice in the stress+exercise group were allowed to voluntarily run on a wheel for 2h after every SDS exposure. Two weeks later, compared to the control group, the stress group showed a higher ratio of time spent in the corner zone of a social interaction paradigm even though SDS did not elicit depressive- and anxiety-like behaviors. We also observed that voluntary exercise, which did not affect muscle weight and gene expression, decreased social avoidance behavior of stressed mice without clear changes in brain monoamine levels. Interestingly, food intake in the stress+exercise group was the greatest among the three groups. To test the effect of the exercise-induced increase in food intake on social behavior, we set up a pair-fed group where food intake was restricted. We then compared these mice to mice in the stress alone group. We found that the ratio of time spent in the corner zone of the social interaction test was not different between ad libitum- and pair-fed groups, although pair-fed mice spent more time in the corner zone when an aggressor mouse was present than when it was absent. In addition, pair-feeding did not show exercise-induced reductions of adrenal gland weight and enhanced the loss of body fat. Our findings indicate that voluntary exercise reduces social avoidance behavior induced by SDS. Further, we determined that SDS and exercise-induced increases in food intake partially influence energy metabolism and social avoidance behavior. Copyright © 2015 Elsevier Inc. All rights reserved.

Mechanisms underlying odorant-induced and spontaneous calcium signals in olfactory receptor neurons of spiny lobsters, Panulirus argus.

PubMed

Tadesse, Tizeta; Derby, Charles D; Schmidt, Manfred

2014-01-01

We determined if a newly developed antennule slice preparation allows studying chemosensory properties of spiny lobster olfactory receptor neurons under in situ conditions with Ca(2+) imaging. We show that chemical stimuli reach the dendrites of olfactory receptor neurons but not their somata, and that odorant-induced Ca(2+) signals in the somata are sufficiently stable over time to allow stimulation with a substantial number of odorants. Pharmacological manipulations served to elucidate the source of odorant-induced Ca(2+) transients and spontaneous Ca(2+) oscillations in the somata of olfactory receptor neurons. Both Ca(2+) signals are primarily mediated by an influx of extracellular Ca(2+) through voltage-activated Ca(2+) channels that can be blocked by CoCl2 and the L-type Ca(2+) channel blocker verapamil. Intracellular Ca(2+) stores contribute little to odorant-induced Ca(2+) transients and spontaneous Ca(2+) oscillations. The odorant-induced Ca(2+) transients as well as the spontaneous Ca(2+) oscillations depend on action potentials mediated by Na(+) channels that are largely TTX-insensitive but blocked by the local anesthetics tetracaine and lidocaine. Collectively, these results corroborate the conclusion that odorant-induced Ca(2+) transients and spontaneous Ca(2+) oscillations in the somata of olfactory receptor neurons closely reflect action potential activity associated with odorant-induced phasic-tonic responses and spontaneous bursting, respectively. Therefore, both types of Ca(2+) signals represent experimentally accessible proxies of spiking.

Diet-induced increases in chemerin are attenuated by exercise and mediate the effect of diet on insulin and HOMA-IR

PubMed Central

Lloyd, Jesse W.; Zerfass, Kristy M.; Heckstall, Ebony M.; Evans, Kristin A.

2015-01-01

Objectives: Chemerin concentrations are elevated in obesity and associated with inflammation and insulin resistance. Exercise improves insulin sensitivity, which may be facilitated by changes in chemerin. We explored the effects of chronic exercise on chemerin levels in diet-induced obese mice. Methods: We divided 40 mice into 4 groups: high-fat diet/exercise, high-fat diet/sedentary, normal diet/exercise, and normal diet/sedentary. A 9-week dietary intervention was followed by a 12-week exercise intervention (treadmill run: 11 m/min for 30 min, 3×/week). We analyzed blood samples before and after the exercise intervention. We used t-tests and linear regression to examine changes in chemerin, insulin resistance, and inflammatory markers, and associations between changes in chemerin and all other biomarkers. Results: Chemerin increased significantly across all mice over the 12-week intervention (mean ± SD = 40.7 ± 77.8%, p = 0.01), and this increase was smaller in the exercise versus sedentary mice (27.2 ± 83.9% versus 54.9 ± 70.5%, p = 0.29). The increase among the high-fat diet/exercise mice was ~44% lower than the increase among the high-fat diet/sedentary mice (55.7 ± 54.9% versus 99.8 ± 57.7%, p = 0.12). The high-fat diet mice showed significant increases in insulin (773.5 ± 1286.6%, p < 0.0001) and homeostatic model assessment of insulin resistance (HOMA-IR; 846.5 ± 1723.3%, p < 0.01). Mediation analyses showed that increases in chemerin explained a substantial amount of the diet-induced increases in insulin and HOMA-IR. Conclusion: Chronic exercise may attenuate diet-driven increases in circulating chemerin, and the insulin resistance associated with a high-fat diet may be mediated by diet-induced increases in chemerin. PMID:26445641

Weight Loss Behaviors Used by Active Duty Air Force Personnel to Maintain Compliance with Weight Control Standards

DTIC Science & Technology

1997-05-01

lose weight. The methods of weight loss reported were exercising , skipping meals, using diet pills, and self- induced vomiting. In each case, females...Restrictive Diet Popular Diet Self- induced Vomifing Laxatives Diuretics Diet Pills Exercise Other Note- N = frequency of resf were allowed to...Rate 69 Demographic Data 69 Exercise 70 Weight Loss Beliefs and Practices 71 Additional Data Collected 76 Implications for Military Health Care

Irisin is a pro-myogenic factor that induces skeletal muscle hypertrophy and rescues denervation-induced atrophy.

PubMed

Reza, Musarrat Maisha; Subramaniyam, Nathiya; Sim, Chu Ming; Ge, Xiaojia; Sathiakumar, Durgalakshmi; McFarlane, Craig; Sharma, Mridula; Kambadur, Ravi

2017-10-24

Exercise induces expression of the myokine irisin, which is known to promote browning of white adipose tissue and has been shown to mediate beneficial effects following exercise. Here we show that irisin induces expression of a number of pro-myogenic and exercise response genes in myotubes. Irisin increases myogenic differentiation and myoblast fusion via activation of IL6 signaling. Injection of irisin in mice induces significant hypertrophy and enhances grip strength of uninjured muscle. Following skeletal muscle injury, irisin injection improves regeneration and induces hypertrophy. The effects of irisin on hypertrophy are due to activation of satellite cells and enhanced protein synthesis. In addition, irisin injection rescues loss of skeletal muscle mass following denervation by enhancing satellite cell activation and reducing protein degradation. These data suggest that irisin functions as a pro-myogenic factor in mice.

Basic guidelines to introduce electric circuit simulation software in a general physics course

NASA Astrophysics Data System (ADS)

Moya, A. A.

2018-05-01

The introduction of electric circuit simulation software for undergraduate students in a general physics course is proposed in order to contribute to the constructive learning of electric circuit theory. This work focuses on the lab exercises based on dc, transient and ac analysis in electric circuits found in introductory physics courses, and shows how students can use the simulation software to do simple activities associated with a lab exercise itself and with related topics. By introducing electric circuit simulation programs in a general physics course as a brief activitiy complementing lab exercise, students develop basic skills in using simulation software, improve their knowledge on the topology of electric circuits and perceive that the technology contributes to their learning, all without reducing the time spent on the actual content of the course.

Exercise-induced bronchospasm.

PubMed

Storms, William W

2009-01-01

Exercise-induced bronchospasm (EIB) is a relatively common condition that affects both recreational and elite athletes. The latest data suggest that it is an inflammatory process, especially in elite athletes. Proper diagnosis is important to differentiate EIB from other respiratory conditions. Effective treatment usually controls this condition.

Strain and thermally induced magnetic dynamics and spin current in magnetic insulators subject to transient optical grating

NASA Astrophysics Data System (ADS)

Wang, Xi-Guang; Chotorlishvili, Levan; Berakdar, Jamal

2017-07-01

We analyze the magnetic dynamics and particularlythe spin current in an open-circuit ferromagnetic insulator irradiated by two intense, phase-locked laser pulses. The interference of the laser beams generates a transient optical grating and a transient spatio-temporal temperature distribution. Both effects lead to elastic and heat waves at the surface and into the bulk of the sample. The strain induced spin current as well as the thermally induced magnonic spin current are evaluated numerically on the basis of micromagnetic simulations using solutions of the heat equation. We observe that the thermo-elastically induced magnonic spin current propagates on a distance larger than the characteristic size of thermal profile, an effect useful for applications in remote detection of spin caloritronics phenomena. Our findings point out that exploiting strain adds a new twist to heat-assisted magnetic switching and spin-current generation for spintronic applications.

Calculi and memory.

PubMed

Kettaneh, A; Gobron, C; Fain, O; Mohib, S; Thomas, M

2001-03-01

We describe a case of transient global amnesia related to symptomatic renal stones. Transient global amnesia has been related to intense emotional or painful experiences, such as sexual intercourse, cold water bathing and trigeminal stimulation. Renal stones may be at the origin of a painful experience and thus may induce transient global amnesia.

Local vibration enhanced the efficacy of passive exercise on mitigating bone loss in hindlimb unloading rats

NASA Astrophysics Data System (ADS)

Huang, Yunfei; Luan, Huiqin; Sun, Lianwen; Bi, Jingfang; Wang, Ying; Fan, Yubo

2017-08-01

Spaceflight induced bone loss is seriously affecting astronauts. Mechanical stimulation from exercise has been shown to restrain bone resorption as well as improve bone formation. Current exercise countermeasures in space cannot prevent it completely. Active exercise may convert to passive exercise in some ways because of the loss of gravity stimulus and inertia of exercise equipment. The aim of this study was to compare the efficacy of passive exercise or/and local vibration on counteracting the deterioration of the musculoskeletal system, including bone, muscle and tendons in tail-suspended rats. We hypothesized that local vibration could enhance the efficacy of passive exercise on countering bone loss. 40 Sprague Dawley rats were randomly distributed into five groups (n = 8, each): tail-suspension (TS), TS+35 Hz vibration (TSV), TS + passive exercise (TSP), TS + passive exercise coupled with 35 Hz vibration (TSPV) and control (CON). Passive exercise or/and local vibration was performed for 21 days. On day 0 and 21, bone mineral density (BMD) was observed by dual energy X-ray absorptiometry (DXA), and trabecular microstructure was evaluated by microcomputer tomography (μCT) analysis in vivo. Mechanical properties of tibia and tendon were determined by a mechanical testing system. Soleus and bone ash weight was tested by an electronic balance. Results showed that the passive exercise could not prevent the decrease of trabecular BMD, microstructure and bone ash weight induced by TS, whereas vibration and passive exercise coupled with local vibration (PV) could. Biomechanical properties of the tibia and tendon in TSPV group significantly increased compared with TS group. In summary, PV in this study was the best method in preventing weightlessness-induced bone loss. Consistent with our hypothesis, local vibration partly enhanced the effect of passive exercise. Furthermore, this study will be useful in improving countermeasure for astronauts, but also for the rehabilitation of disused or aged osteoporosis.

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.

The Impact of Central and Peripheral Cyclooxygenase Enzyme Inhibition on Exercise-Induced Elevations in Core Body Temperature.

PubMed

Veltmeijer, Matthijs T W; Veeneman, Dineke; Bongers, Coen C C W; Netea, Mihai G; van der Meer, Jos W; Eijsvogels, Thijs M H; Hopman, Maria T E

2017-05-01

Exercise increases core body temperature (T C ) due to metabolic heat production. However, the exercise-induced release of inflammatory cytokines including interleukin-6 (IL-6) may also contribute to the rise in T C by increasing the hypothalamic temperature set point. This study investigated whether the exercise-induced increase in T C is partly caused by an altered hypothalamic temperature set point. Fifteen healthy, active men age 36 ± 14 y were recruited. Subjects performed submaximal treadmill exercise in 3 randomized test conditions: (1) 400 mg ibuprofen and 1000 mg acetaminophen (IBU/APAP), (2) 1000 mg acetaminophen (APAP), and (3) a control condition (CTRL). Acetaminophen and ibuprofen were used to block the effect of IL-6 at a central and peripheral level, respectively. T C , skin temperature, and heart rate were measured continuously during the submaximal exercise tests. Baseline values of T C , skin temperature, and heart rate did not differ across conditions. Serum IL-6 concentrations increased in all 3 conditions. A significantly lower peak T C was observed in IBU/APAP (38.8°C ± 0.4°C) vs CTRL (39.2°C ± 0.5°C, P = .02) but not in APAP (38.9°C ± 0.4°C) vs CTRL. Similarly, a lower ΔT C was observed in IBU/APAP (1.7°C ± 0.3°C) vs CTRL (2.0°C ± 0.5°C, P < .02) but not in APAP (1.7°C ± 0.5°C) vs CTRL. No differences were observed in skin temperature and heart-rate responses across conditions. The combined administration of acetaminophen and ibuprofen resulted in an attenuated increase in T C during exercise compared with a CTRL. This observation suggests that a prostaglandin-E2-induced elevated hypothalamic temperature set point may contribute to the exercise-induced rise in T C .

Long-Term Exercise Is a Potent Trigger for ΔFosB Induction in the Hippocampus along the dorso–ventral Axis

PubMed Central

Nishijima, Takeshi; Kawakami, Masashi; Kita, Ichiro

2013-01-01

Physical exercise improves multiple aspects of hippocampal function. In line with the notion that neuronal activity is key to promoting neuronal functions, previous literature has consistently demonstrated that acute bouts of exercise evoke neuronal activation in the hippocampus. Repeated activating stimuli lead to an accumulation of the transcription factor ΔFosB, which mediates long-term neural plasticity. In this study, we tested the hypothesis that long-term voluntary wheel running induces ΔFosB expression in the hippocampus, and examined any potential region-specific effects within the hippocampal subfields along the dorso–ventral axis. Male C57BL/6 mice were housed with or without a running wheel for 4 weeks. Long-term wheel running significantly increased FosB/ΔFosB immunoreactivity in all hippocampal regions measured (i.e., in the DG, CA1, and CA3 subfields of both the dorsal and ventral hippocampus). Results confirmed that wheel running induced region-specific expression of FosB/ΔFosB immunoreactivity in the cortex, suggesting that the uniform increase in FosB/ΔFosB within the hippocampus is not a non-specific consequence of running. Western blot data indicated that the increased hippocampal FosB/ΔFosB immunoreactivity was primarily due to increased ΔFosB. These results suggest that long-term physical exercise is a potent trigger for ΔFosB induction throughout the entire hippocampus, which would explain why exercise can improve both dorsal and ventral hippocampus-dependent functions. Interestingly, we found that FosB/ΔFosB expression in the DG was positively correlated with the number of doublecortin-immunoreactive (i.e., immature) neurons. Although the mechanisms by which ΔFosB mediates exercise-induced neurogenesis are still uncertain, these data imply that exercise-induced neurogenesis is at least activity dependent. Taken together, our current results suggest that ΔFosB is a new molecular target involved in regulating exercise-induced hippocampal plasticity. PMID:24282574

The opposite effects of nandrolone decanoate and exercise on anxiety levels in rats may involve alterations in hippocampal parvalbumin–positive interneurons

PubMed Central

Selakovic, Dragica; Joksimovic, Jovana; Zaletel, Ivan; Puskas, Nela; Matovic, Milovan

2017-01-01

The aim of this study was to evaluate the behavioral effects of chronic (six weeks) nandrolone decanoate (ND, 20 mg/kg, s.c., weekly in single dose) administration (in order to mimic heavy human abuse), and exercise (swimming protocol of 60 minutes a day, five days in a row/two days break), applied alone and simultaneously with ND, in male rats (n = 40). Also, we evaluated the effects of those protocols on hippocampal parvalbumin (PV) content and the possible connection between the alterations in certain parts of hippocampal GABAergic system and behavioral patterns. Both ND and exercise protocols induced increase in testosterone, dihydrotestosterone and estradiol blood levels. Our results confirmed anxiogenic effects of ND observed in open field (OF) test (decrease in the locomotor activity, as well as in frequency and cumulative duration in the centre zone) and in elevated plus maze (EPM) test (decrease in frequency and cumulative duration in open arms, and total exploratory activity), that were accompanied with a mild decrease in the number of PV interneurons in hippocampus. Chronic exercise protocol induced significant increase in hippocampal PV neurons (dentate gyrus and CA1 region), followed by anxiolytic-like behavioral changes, observed in both OF and EPM (increase in all estimated parameters), and in evoked beam-walking test (increase in time to cross the beam), compared to ND treated animals. The applied dose of ND was sufficient to attenuate beneficial effects of exercise in rats by means of decreased exercise-induced anxiolytic effect, as well as to reverse exercise-induced augmentation in number of PV immunoreactive neurons in hippocampus. Our results implicate the possibility that alterations in hippocampal PV interneurons (i.e. GABAergic system) may be involved in modulation of anxiety level induced by ND abuse and/or extended exercise protocols. PMID:29232412

The opposite effects of nandrolone decanoate and exercise on anxiety levels in rats may involve alterations in hippocampal parvalbumin-positive interneurons.

PubMed

Selakovic, Dragica; Joksimovic, Jovana; Zaletel, Ivan; Puskas, Nela; Matovic, Milovan; Rosic, Gvozden

2017-01-01

The aim of this study was to evaluate the behavioral effects of chronic (six weeks) nandrolone decanoate (ND, 20 mg/kg, s.c., weekly in single dose) administration (in order to mimic heavy human abuse), and exercise (swimming protocol of 60 minutes a day, five days in a row/two days break), applied alone and simultaneously with ND, in male rats (n = 40). Also, we evaluated the effects of those protocols on hippocampal parvalbumin (PV) content and the possible connection between the alterations in certain parts of hippocampal GABAergic system and behavioral patterns. Both ND and exercise protocols induced increase in testosterone, dihydrotestosterone and estradiol blood levels. Our results confirmed anxiogenic effects of ND observed in open field (OF) test (decrease in the locomotor activity, as well as in frequency and cumulative duration in the centre zone) and in elevated plus maze (EPM) test (decrease in frequency and cumulative duration in open arms, and total exploratory activity), that were accompanied with a mild decrease in the number of PV interneurons in hippocampus. Chronic exercise protocol induced significant increase in hippocampal PV neurons (dentate gyrus and CA1 region), followed by anxiolytic-like behavioral changes, observed in both OF and EPM (increase in all estimated parameters), and in evoked beam-walking test (increase in time to cross the beam), compared to ND treated animals. The applied dose of ND was sufficient to attenuate beneficial effects of exercise in rats by means of decreased exercise-induced anxiolytic effect, as well as to reverse exercise-induced augmentation in number of PV immunoreactive neurons in hippocampus. Our results implicate the possibility that alterations in hippocampal PV interneurons (i.e. GABAergic system) may be involved in modulation of anxiety level induced by ND abuse and/or extended exercise protocols.

Exercise aggravates cardiovascular risks and mortality in rats with disrupted nitric oxide pathway and treated with recombinant human erythropoietin.

PubMed

Meziri, Fayçal; Binda, Delphine; Touati, Sabeur; Pellegrin, Maxime; Berthelot, Alain; Touyz, Rhian M; Laurant, Pascal

2011-08-01

Chronic administration of recombinant human erythropoietin (rHuEPO) can generate serious cardiovascular side effects such as arterial hypertension (HTA) in clinical and sport fields. It is hypothesized that nitric oxide (NO) can protect from noxious cardiovascular effects induced by chronic administration of rHuEPO. On this base, we studied the cardiovascular effects of chronic administration of rHuEPO in exercise-trained rats treated with an inhibitor of NO synthesis (L-NAME). Rats were treated or not with rHuEPO and/or L-NAME during 6 weeks. During the same period, rats were subjected to treadmill exercise. The blood pressure was measured weekly. Endothelial function of isolated aorta and small mesenteric arteries were studied and the morphology of the latter was investigated. L-NAME induced hypertension (197 ± 6 mmHg, at the end of the protocol). Exercise prevented the rise in blood pressure induced by L-NAME (170 ± 5 mmHg). However, exercise-trained rats treated with both rHuEPO and L-NAME developed severe hypertension (228 ± 9 mmHg). Furthermore, in these exercise-trained rats treated with rHuEPO/L-NAME, the acetylcholine-induced relaxation was markedly impaired in isolated aorta (60% of maximal relaxation) and small mesenteric arteries (53%). L-NAME hypertension induced an internal remodeling of small mesenteric arteries that was not modified by exercise, rHuEPO or both. Vascular ET-1 production was not increased in rHuEPO/L-NAME/training hypertensive rats. Furthermore, we observed that rHuEPO/L-NAME/training hypertensive rats died during the exercise or the recovery period (mortality 51%). Our findings suggest that the use of rHuEPO in sport, in order to improve physical performance, represents a high and fatal risk factor, especially with pre-existing cardiovascular risk.

Exercise-induced dehydration alters pulmonary function but does not modify airway responsiveness to dry air in athletes with mild asthma

PubMed Central

Romer, L. M.

2017-01-01

Local airway water loss is the main physiological trigger for exercise-induced bronchoconstriction (EIB). Our aim was to investigate the effects of whole body water loss on airway responsiveness and pulmonary function in athletes with mild asthma and/or EIB. Ten recreational athletes with a medical diagnosis of mild asthma and/or EIB completed a randomized, crossover study. Pulmonary function tests, including spirometry, whole body plethysmography, and diffusing capacity of the lung for carbon monoxide (DlCO), were conducted before and after three conditions: 1) 2 h of exercise in the heat with no fluid intake (dehydration), 2) 2 h of exercise with ad libitum fluid intake (control), and 3) a time-matched rest period (rest). Airway responsiveness was assessed 2 h postexercise/rest via eucapnic voluntary hyperpnea (EVH) to dry air. Exercise in the heat with no fluid intake induced a state of mild dehydration, with a body mass loss of 2.3 ± 0.8% (SD). After EVH, airway narrowing was not different between conditions: median (interquartile range) maximum fall in forced expiratory volume in 1 s was 13 (7–15)%, 11 (9–24)%, and 12 (7–20)% in dehydration, control, and rest conditions, respectively. Dehydration caused a significant reduction in forced vital capacity (300 ± 190 ml, P = 0.001) and concomitant increases in residual volume (260 ± 180 ml, P = 0.001) and functional residual capacity (260 ± 250 ml, P = 0.011), with no change in DlCO. Mild exercise-induced dehydration does not exaggerate airway responsiveness to dry air in athletes with mild asthma/EIB but may affect small airway function. NEW & NOTEWORTHY This study is the first to investigate the effect of whole body dehydration on airway responsiveness. Our data suggest that the airway response to dry air hyperpnea in athletes with mild asthma and/or exercise-induced bronchoconstriction is not exacerbated in a state of mild dehydration. On the basis of alterations in lung volumes, however, exercise-induced dehydration appears to compromise small airway function. PMID:28280109

Exercise-induced dehydration alters pulmonary function but does not modify airway responsiveness to dry air in athletes with mild asthma.

PubMed

Simpson, A J; Romer, L M; Kippelen, P

2017-05-01

Local airway water loss is the main physiological trigger for exercise-induced bronchoconstriction (EIB). Our aim was to investigate the effects of whole body water loss on airway responsiveness and pulmonary function in athletes with mild asthma and/or EIB. Ten recreational athletes with a medical diagnosis of mild asthma and/or EIB completed a randomized, crossover study. Pulmonary function tests, including spirometry, whole body plethysmography, and diffusing capacity of the lung for carbon monoxide (Dl CO ), were conducted before and after three conditions: 1 ) 2 h of exercise in the heat with no fluid intake (dehydration), 2 ) 2 h of exercise with ad libitum fluid intake (control), and 3 ) a time-matched rest period (rest). Airway responsiveness was assessed 2 h postexercise/rest via eucapnic voluntary hyperpnea (EVH) to dry air. Exercise in the heat with no fluid intake induced a state of mild dehydration, with a body mass loss of 2.3 ± 0.8% (SD). After EVH, airway narrowing was not different between conditions: median (interquartile range) maximum fall in forced expiratory volume in 1 s was 13 (7-15)%, 11 (9-24)%, and 12 (7-20)% in dehydration, control, and rest conditions, respectively. Dehydration caused a significant reduction in forced vital capacity (300 ± 190 ml, P = 0.001) and concomitant increases in residual volume (260 ± 180 ml, P = 0.001) and functional residual capacity (260 ± 250 ml, P = 0.011), with no change in Dl CO Mild exercise-induced dehydration does not exaggerate airway responsiveness to dry air in athletes with mild asthma/EIB but may affect small airway function. NEW & NOTEWORTHY This study is the first to investigate the effect of whole body dehydration on airway responsiveness. Our data suggest that the airway response to dry air hyperpnea in athletes with mild asthma and/or exercise-induced bronchoconstriction is not exacerbated in a state of mild dehydration. On the basis of alterations in lung volumes, however, exercise-induced dehydration appears to compromise small airway function. Copyright © 2017 the American Physiological Society.

The impact of exercise-induced core body temperature elevations on coagulation responses.

PubMed

Veltmeijer, Matthijs T W; Eijsvogels, Thijs M H; Barteling, Wideke; Verbeek-Knobbe, Kitty; van Heerde, Waander L; Hopman, Maria T E

2017-02-01

Exercise induces changes in haemostatic parameters and core body temperature (CBT). We aimed to assess whether exercise-induced elevations in CBT induce pro-thrombotic changes in a dose-dependent manner. Observational study. CBT and haemostatic responses were measured in 62 participants of a 15-km road race at baseline and immediately after finishing. As haemostasis assays are routinely performed at 37°C, we corrected the assay temperature for the individual's actual CBT at baseline and finish in a subgroup of n=25. All subjects (44±11 years, 69% male) completed the race at a speed of 12.1±1.8km/h. CBT increased significantly from 37.6±0.4°C to 39.4±0.8°C (p<0.001). Post-exercise, haemostatic activity was increased, as expressed by accelerated thrombin generation and an attenuated plasmin response. Synchronizing assay temperature to the subjects' actual CBT resulted in additional differences and stronger acceleration of thrombin generation parameters. This study demonstrates that exercise induces a prothrombotic state, which might be partially dependent on the magnitude of the exercise-induced CBT rise. Synchronizing the assay temperature to approximate the subject's CBT is essential to obtain more accurate insight in the haemostatic balance during thermoregulatory challenging situations. Finally, this study shows that short-lasting exposure to a CBT of 41.2°C does not result in clinical symptoms of severe coagulation. We therefore hypothesize that prolonged exposure to a high CBT or an individual-specific CBT threshold needs to be exceeded before derailment of the haemostatic balance occurs. Copyright © 2016 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

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.

Effect of exercise training and food restriction on endothelium-dependent relaxation in the Otsuka Long-Evans Tokushima Fatty rat, a model of spontaneous NIDDM.

PubMed

Sakamoto, S; Minami, K; Niwa, Y; Ohnaka, M; Nakaya, Y; Mizuno, A; Kuwajima, M; Shima, K

1998-01-01

We investigated whether endothelial function may be impaired in the Otsuka Long-Evans Tokushima Fatty (OLETF) rat, a model of spontaneous NIDDM. The effect of exercise training and food restriction on endothelial function was also studied. OLETF rats were divided into three groups at age 16 weeks: sedentary, exercise trained, and food restricted (70% of the food intake of sedentary rats). Otsuka Long-Evans Tokushima rats were used as the age-matched nondiabetic controls. Endothelium-dependent relaxation of the thoracic aorta induced by histamine was significantly attenuated in the sedentary or food-restricted rats, and exercise training improved endothelial function. Relaxation induced by sodium nitroprusside, a donor of nitric oxide, did not differ significantly among groups. Both exercise training and food restriction significantly suppressed plasma levels of glucose and insulin and serum levels of triacylglycerol and cholesterol and reduced the accumulation of abdominal fat. Insulin sensitivity, as measured by the hyperinsulinemic-euglycemic clamp technique, was significantly decreased in sedentary rats but was enhanced in exercise-trained and food-restricted rats. The urinary excretion of nitrite was significantly decreased in sedentary and food-restricted rats compared with nondiabetic rats and was significantly increased in exercise-trained rats. These results indicate that exercise training, but not food restriction, prevents endothelial dysfunction in NIDDM rats, presumably due to the exercise-induced increase in the production of nitric oxide.

Resistance to exercise-induced weight loss: compensatory behavioral adaptations.

PubMed

Melanson, Edward L; Keadle, Sarah Kozey; Donnelly, Joseph E; Braun, Barry; King, Neil A

2013-08-01

In many interventions that are based on an exercise program intended to induce weight loss, the mean weight loss observed is modest and sometimes far less than what the individual expected. The individual responses are also widely variable, with some individuals losing a substantial amount of weight, others maintaining weight, and a few actually gaining weight. The media have focused on the subpopulation that loses little weight, contributing to a public perception that exercise has limited utility to cause weight loss. The purpose of the symposium was to present recent, novel data that help explain how compensatory behaviors contribute to a wide discrepancy in exercise-induced weight loss. The presentations provide evidence that some individuals adopt compensatory behaviors, that is, increased energy intake and/or reduced activity, that offset the exercise energy expenditure and limit weight loss. The challenge for both scientists and clinicians is to develop effective tools to identify which individuals are susceptible to such behaviors and to develop strategies to minimize their effect.

Resistance to exercise-induced weight loss: compensatory behavioral adaptations

PubMed Central

Melanson, Edward L.; Keadle, Sarah Kozey; Donnelly, Joseph E.; Braun, Barry; King, Neil A.

2013-01-01

In many interventions that are based on an exercise program intended to induce weight loss, the mean weight loss observed is modest and sometimes far less than the individual expected. The individual responses are also widely variable, with some individuals losing a substantial amount of weight, others maintaining weight, and a few actually gaining weight. The media have focused on the sub-population that loses little weight, contributing to a public perception that exercise has limited utility to cause weight loss. The purpose of the symposium was to present recent, novel data that help explain how compensatory behaviors contribute to a wide discrepancy in exercise-induced weight loss. The presentations provide evidence that some individuals adopt compensatory behaviors, i.e. increased energy intake and/or reduced activity, that offset the exercise energy expenditure and limit weight loss. The challenge for both scientists and clinicians is to develop effective tools to identify which individuals are susceptible to such behaviors, and to develop strategies to minimize their impact. PMID:23470300

Exercise promotes alpha7 integrin gene transcription and protection of skeletal muscle.

PubMed

Boppart, Marni D; Volker, Sonja E; Alexander, Nicole; Burkin, Dean J; Kaufman, Stephen J

2008-11-01

The alpha7beta1 integrin is increased in skeletal muscle in response to injury-producing exercise, and transgenic overexpression of this integrin in mice protects against exercise-induced muscle damage. The present study investigates whether the increase in the alpha7beta1 integrin observed in wild-type mice in response to exercise is due to transcriptional regulation and examines whether mobilization of the integrin at the myotendinous junction (MTJ) is a key determinant in its protection against damage. A single bout of downhill running exercise selectively increased transcription of the alpha7 integrin gene in 5-wk-old wild-type mice 3 h postexercise, and an increased alpha7 chain was detected in muscle sarcolemma adjacent to tendinous tissue immediately following exercise. The alpha7B, but not alpha7A isoform, was found concentrated and colocalized with tenascin-C in muscle fibers lining the MTJ. To further validate the importance of the integrin in the protection against muscle damage following exercise, muscle injury was quantified in alpha7(-/-) mice. Muscle damage was extensive in alpha7(-/-) mice in response to both a single and repeated bouts of exercise and was largely restricted to areas of high MTJ concentration and high mechanical force near the Achilles tendon. These results suggest that exercise-induced muscle injury selectively increases transcription of the alpha7 integrin gene and promotes a rapid change in the alpha7beta integrin at the MTJ. These combined molecular and cellular alterations are likely responsible for integrin-mediated attenuation of exercise-induced muscle damage.

Resistance exercise-induced fluid shifts: change in active muscle size and plasma volume

NASA Technical Reports Server (NTRS)

Ploutz-Snyder, L. L.; Convertino, V. A.; Dudley, G. A.

1995-01-01

The purpose of this study was to test the hypothesis that the reduction in plasma volume (PV) induced by resistance exercise reflects fluid loss to the extravascular space and subsequently selective increase in cross-sectional area (CSA) of active but not inactive skeletal muscle. We compared changes in active and inactive muscle CSA and PV after barbell squat exercise. Magnetic resonance imaging (MRI) was used to quantify muscle involvement in exercise and to determine CSA of muscle groups or individual muscles [vasti (VS), adductor (Add), hamstring (Ham), and rectus femoris (RF)]. Muscle involvement in exercise was determined using exercise-induced contrast shift in spin-spin relaxation time (T2)-weighted MR images immediately postexercise. Alterations in muscle size were based on the mean CSA of individual slices. Hematocrit, hemoglobin, and Evans blue dye were used to estimate changes in PV. Muscle CSA and PV data were obtained preexercise and immediately postexercise and 15 and 45 min thereafter. A hierarchy of muscle involvement in exercise was found such that VS > Add > Ham > RF, with the Ham and RF showing essentially no involvement. CSA of the VS and Add muscle groups were increased 10 and 5%, respectively, immediately after exercise in each thigh with no changes in Ham and RF CSA. PV was decreased 22% immediately following exercise. The absolute loss of PV was correlated (r2 = 0.75) with absolute increase in muscle CSA immediately postexercise, supporting the notion that increased muscle size after resistance exercise reflects primarily fluid movement from the vascular space into active but not inactive muscle.

Ventilatory and circulatory responses at the onset of exercise in man following heart or heart-lung transplantation.

PubMed Central

Banner, N; Guz, A; Heaton, R; Innes, J A; Murphy, K; Yacoub, M

1988-01-01

1. Ventilatory and cardiovascular responses to the onset of voluntary and electrically induced leg exercise were studied in six patients following heart transplantation and five following heart-lung transplantation; the results were compared between the patient groups and also with responses from a group of normal subjects. 2. Oxygen consumption, carbon dioxide production and ventilation and its components were measured over two 30 s periods prior to, and two 30 s periods following, the onset of exercise. Relative changes in stroke volume and cardiac output were derived from ensemble-averaged Doppler measurements of ascending aortic blood velocity over the same 30 s periods. 3. None of the groups of subjects showed any significant differences in responses to voluntary exercise compared to electrically induced exercise of similar work pattern and intensity. 4. Compared to normal controls, the transplanted subjects showed higher resting heart rates which did not increase at the onset of exercise; stroke volume increased, but less than in the normal subjects. The resulting cardiac output increases in the transplanted subjects were minimal compared to the normal subjects. 5. Ventilation and oxygen uptake increased immediately and with similar magnitude in all three groups. 6. These results show that in the same individual it is possible to have an appropriate ventilatory response to the onset of exercise in the presumed absence of a normal corticospinal input to the exercising muscles (electrically induced exercise) and afferent neural information from the lungs and heart, and in the absence of a normal circulatory response to exercise. The mechanisms underlying this ventilatory response remain undetermined. PMID:3136247

Sex and Exercise Interact to Alter the Expression of Anabolic Androgenic Steroid-Induced Anxiety-Like Behaviors in the Mouse

PubMed Central

Onakomaiya, Marie M.; Porter, Donna M.; Oberlander, Joseph G.; Henderson, Leslie P.

2014-01-01

Anabolic androgenic steroids (AAS) are taken by both sexes to enhance athletic performance and body image, nearly always in conjunction with an exercise regime. Although taken to improve physical attributes, chronic AAS use can promote negative behavior, including anxiety. Few studies have directly compared the impact of AAS use in males versus females or assessed the interaction of exercise and AAS. We show that AAS increase anxiety-like behaviors in female but not male mice and that voluntary exercise accentuates these sex-specific differences. We also show that levels of the anxiogenic peptide corticotrophin releasing factor (CRF) are significantly greater in males, but that AAS selectively increase CRF levels in females, thus abrogating this sex-specific difference. Exercise did not ameliorate AAS-induced anxiety or alter CRF levels in females. Exercise was anxiolytic in males, but this behavioral outcome did not correlate with CRF levels. Brain-derived neurotrophic factor (BDNF) has also been implicated in the expression of anxiety. As with CRF, levels of hippocampal BDNF mRNA were significantly greater in males than females. AAS and exercise were without effect on BDNF mRNA in females. In males, anxiolytic effects of exercise correlated with increased BDNF mRNA, however AAS-induced changes in BDNF mRNA and anxiety did not. In sum, we find that AAS elicit sex-specific differences in anxiety and that voluntary exercise accentuates these differences. In addition, our data suggest that these behavioral outcomes may reflect convergent actions of AAS and exercise on a sexually differentiated CRF signaling system within the extended amygdala. PMID:24768711

High fat diet and exercise lead to a disrupted and pathogenic DNA methylome in mouse liver.

PubMed

Zhou, Dan; Hlady, Ryan A; Schafer, Marissa J; White, Thomas A; Liu, Chen; Choi, Jeong-Hyeon; Miller, Jordan D; Roberts, Lewis R; LeBrasseur, Nathan K; Robertson, Keith D

2017-01-02

High-fat diet consumption and sedentary lifestyle elevates risk for obesity, non-alcoholic fatty liver disease, and cancer. Exercise training conveys health benefits in populations with or without these chronic conditions. Diet and exercise regulate gene expression by mediating epigenetic mechanisms in many tissues; however, such effects are poorly documented in the liver, a central metabolic organ. To dissect the consequences of diet and exercise on the liver epigenome, we measured DNA methylation, using reduced representation bisulfite sequencing, and transcription, using RNA-seq, in mice maintained on a fast food diet with sedentary lifestyle or exercise, compared with control diet with and without exercise. Our analyses reveal that genome-wide differential DNA methylation and expression of gene clusters are induced by diet and/or exercise. A combination of fast food and exercise triggers extensive gene alterations, with enrichment of carbohydrate/lipid metabolic pathways and muscle developmental processes. Through evaluation of putative protective effects of exercise on diet-induced DNA methylation, we show that hypermethylation is effectively prevented, especially at promoters and enhancers, whereas hypomethylation is only partially attenuated. We assessed diet-induced DNA methylation changes associated with liver cancer-related epigenetic modifications and identified significant increases at liver-specific enhancers in fast food groups, suggesting partial loss of liver cell identity. Hypermethylation at a subset of gene promoters was associated with inhibition of tissue development and promotion of carcinogenic processes. Our study demonstrates extensive reprogramming of the epigenome by diet and exercise, emphasizing the functional relevance of epigenetic mechanisms as an interface between lifestyle modifications and phenotypic alterations.

Platelet activation in essential hypertension during exercise: pre- and post-treatment changes with an angiotensin II receptor blocker.

PubMed

Gkaliagkousi, Eugenia; Gavriilaki, Eleni; Yiannaki, Efi; Markala, Dimitra; Papadopoulos, Nikolaos; Triantafyllou, Areti; Anyfanti, Panagiota; Petidis, Konstantinos; Garypidou, Vasileia; Doumas, Michael; Ferro, Albert; Douma, Stella

2014-04-01

Acute exercise may exert deleterious effects on the cardiovascular system through a variety of pathophysiological mechanisms, including increased platelet activation. However, the degree of exercise-induced platelet activation in untreated hypertensive (UH) individuals as compared with normotensive (NT) individuals has yet to be established. Furthermore, the effect of antihypertensive treatment on exercise-induced platelet activation in essential hypertension (EH) remains unknown. Study 1 consisted of 30 UH and 15 NT subjects. UH subjects who received treatment were included in study 2 and were followed-up after a 3-month treatment period with an angiotensin II receptor blocker (ARB; valsartan). Circulating monocyte-platelet aggregates (MPA) and platelet P-selectin were measured as platelet activation markers at baseline, immediately after a treadmill exercise test, and 10, 30, and 90 minutes later. Maximal platelet activation was observed at 10 minutes after peak exercise in both groups. In UH subjects, MPA levels remained increased at 30 minutes after peak exercise, despite BP fall to baseline levels. MPA levels were significantly higher in UH subjects than NT subjects at maximal exercise and at 10 and 30 minutes of recovery. Post-treatment MPA levels increased significantly only at 10 minutes into recovery and were similar to those of NT subjects. Acute high-intensity exercise exaggerates platelet activation in untreated patients with EH compared with NT individuals. Angiotensin II receptor blockade with adequate BP control greatly improves exercise-induced platelet activation in EH. Further studies are needed to clarify whether this phenomenon depends purely on BP lowering or benefits also from the pleiotropic effects of ARBs.

Changes in fMRI activation in anterior hippocampus and motor cortex during memory retrieval after an intense exercise intervention.

PubMed

Wagner, Gerd; Herbsleb, Marco; de la Cruz, Feliberto; Schumann, Andy; Köhler, Stefanie; Puta, Christian; Gabriel, Holger W; Reichenbach, Jürgen R; Bär, Karl-Jürgen

2017-03-01

Strong evidence indicates that regular aerobic training induces beneficial effects on cognitive functions. The present controlled fMRI study was designed to investigate the impact of a short-term intense aerobic exercise on the pattern of functional activation during the retrieval of learned pair-associates in 17 young and healthy male adults compared to 17 matched control subjects. We further aimed to relate putative changes in hippocampal activation to postulated changes in the exercised-induced brain derived neurotrophic factor (BDNF). The supervised exercise program was performed on a bicycle ergometer and lasted six weeks, with three aerobic sessions per week. We found profound improvement of physical fitness in most subjects indicated by the target parameter 'individual anaerobic threshold'. Significant improvements in the cognitive performance were detected in the exercise group, but also in the control group. We observed significant differences in the activation pattern of the left anterior hippocampus during the pair-associates task after the intervention. We could also show a significant positive correlation between changes in exercise-induced BDNF and left anterior hippocampal activation. Moreover, we observed the brain's motor network to be significantly stronger activated after the exercise intervention. Thus, our results suggest BDNF dependent activation changes of the hippocampus in addition to previously described structural changes after exercise. Copyright © 2017 Elsevier B.V. All rights reserved.

Effects of caffeinated chewing gum on muscle pain during submaximal isometric exercise in individuals with fibromyalgia.

PubMed

Umeda, Masataka; Kempka, Laura; Weatherby, Amy; Greenlee, Brennan; Mansion, Kimberly

2016-04-01

Physical activity is important to manage symptom of fibromyalgia (FM); however, individuals with FM typically experience augmented muscle pain during exercise. This study examined the effects of caffeinated chewing gum on exercise-induced muscle pain in individuals with FM. This study was conducted with a double-blind, placebo-controlled, cross-over design. Twenty-three patients with FM completed a caffeine condition where they consumed a caffeinated chewing gum that contains 100mg of caffeine, and a placebo condition where they consumed a non-caffeinated chewing gum. They completed isometric handgrip exercise at 25% of their maximal strength for 3 min, and muscle pain rating (MPR) was recorded every 30s during exercise. Clinical pain severity was assessed in each condition using a pain questionnaire. The order of the two conditions was randomly determined. MPR increased during exercise, but caffeinated chewing gum did not attenuate the increase in MPR compared to placebo gum. Clinical pain severity was generally associated with the average MPR and the caffeine effects on MPR, calculated as difference in the average MPR between the two conditions. The results suggest that more symptomatic individuals with FM may experience greater exercise-induced muscle pain, but benefit more from caffeinated chewing gum to reduce exercise-induced muscle pain. Copyright © 2016 Elsevier Inc. All rights reserved.

In Healthy Young Men, a Short Exhaustive Exercise Alters the Oxidative Stress Only Slightly, Independent of the Actual Fitness

PubMed Central

Finkler, Maya; Hochman, Ayala; Pinchuk, Ilya; Lichtenberg, Dov

2016-01-01

The aim of the present study was to evaluate the apparent disagreement regarding the effect of a typical cycling progressive exercise, commonly used to assess VO2max, on the kinetics of ex vivo copper induced peroxidation of serum lipids. Thirty-two (32) healthy young men, aged 24–30 years, who do not smoke and do not take any food supplements, participated in the study. Blood was withdrawn from each participant at three time points (before the exercise and 5 minutes and one hour after exercise). Copper induced peroxidation of sera made of the blood samples was monitored by spectrophotometry. For comparison, we also assayed TBARS concentration and the activity of oxidation-related enzymes. The physical exercise resulted in a slight and reversible increase of TBARS and slight changes in the activities of the studied antioxidant enzymes and the lag preceding peroxidation did not change substantially. Most altered parameters returned to baseline level one hour after exercise. Notably, the exercise-induced changes in OS did not correlate with the physical fitness of the subjects, as evaluated in this study (VO2max = 30–60 mL/min/kg). We conclude that in healthy young fit men a short exhaustive exercise alters only slightly the OS, independent of the actual physical fitness. PMID:26989456

Voluntary Exercise Preconditioning Activates Multiple Antiapoptotic Mechanisms and Improves Neurological Recovery after Experimental Traumatic Brain Injury

PubMed Central

Zhao, Zaorui; Sabirzhanov, Boris; Wu, Junfang; Faden, Alan I.

2015-01-01

Abstract Physical activity can attenuate neuronal loss, reduce neuroinflammation, and facilitate recovery after brain injury. However, little is known about the mechanisms of exercise-induced neuroprotection after traumatic brain injury (TBI) or its modulation of post-traumatic neuronal cell death. Voluntary exercise, using a running wheel, was conducted for 4 weeks immediately preceding (preconditioning) moderate-level controlled cortical impact (CCI), a well-established experimental TBI model in mice. Compared to nonexercised controls, exercise preconditioning (pre-exercise) improved recovery of sensorimotor performance in the beam walk task, as well as cognitive/affective functions in the Morris water maze, novel object recognition, and tail-suspension tests. Further, pre-exercise reduced lesion size, attenuated neuronal loss in the hippocampus, cortex, and thalamus, and decreased microglial activation in the cortex. In addition, exercise preconditioning activated the brain-derived neurotrophic factor pathway before trauma and amplified the injury-dependent increase in heat shock protein 70 expression, thus attenuating key apoptotic pathways. The latter include reduction in CCI-induced up-regulation of proapoptotic B-cell lymphoma 2 (Bcl-2)-homology 3–only Bcl-2 family molecules (Bid, Puma), decreased mitochondria permeabilization with attenuated release of cytochrome c and apoptosis-inducing factor (AIF), reduced AIF translocation to the nucleus, and attenuated caspase activation. Given these neuroprotective actions, voluntary physical exercise may serve to limit the consequences of TBI. PMID:25419789

Exercise-induced muscle glucose uptake in mice with graded, muscle-specific GLUT-4 deletion.

PubMed

Howlett, Kirsten F; Andrikopoulos, Sofianos; Proietto, Joseph; Hargreaves, Mark

2013-08-01

To investigate the importance of the glucose transporter GLUT-4 for muscle glucose uptake during exercise, transgenic mice with skeletal muscle GLUT-4 expression approximately 30-60% of normal (CON) and approximately 5-10% of normal (KO) were generated using the Cre/Lox system and compared with wild-type (WT) mice during approximately 40 min of treadmill running (KO: 37.7 ± 1.3 min; WT: 40 min; CON: 40 min, P = 0.18). In WT and CON animals, exercise resulted in an overall increase in muscle glucose uptake. More specifically, glucose uptake was increased in red gastrocnemius of WT mice and in the soleus and red gastrocnemius of CON mice. In contrast, the exercise-induced increase in muscle glucose uptake in all muscles was completely abolished in KO mice. Muscle glucose uptake increased during exercise in both red and white quadriceps of WT mice, while the small increases in CON mice were not statistically significant. In KO mice, there was no change at all in quadriceps muscle glucose uptake. No differences in muscle glycogen use during exercise were observed between any of the groups. However, there was a significant increase in plasma glucose levels after exercise in KO mice. The results of this study demonstrated that a reduction in skeletal muscle GLUT-4 expression to approximately 10% of normal levels completely abolished the exercise-induced increase in muscle glucose uptake.

Peripheral Vasoconstriction and Abnormal Parasympathetic Response to Sighs and Transient Hypoxia in Sickle Cell Disease

PubMed Central

Sangkatumvong, Suvimol; Khoo, Michael C. K.; Kato, Roberta; Detterich, Jon A.; Bush, Adam; Keens, Thomas G.; Meiselman, Herbert J.; Wood, John C.

2011-01-01

Rationale: Sickle cell disease is an inherited blood disorder characterized by vasoocclusive crises. Although hypoxia and pulmonary disease are known risk factors for these crises, the mechanisms that initiate vasoocclusive events are not well known. Objectives: To study the relationship between transient hypoxia, respiration, and microvascular blood flow in patients with sickle cell. Methods: We established a protocol that mimics nighttime hypoxic episodes and measured microvascular blood flow to determine if transient hypoxia causes a decrease in microvascular blood flow. Significant desaturations were induced safely by five breaths of 100% nitrogen. Measurements and Main Results: Desaturation did not induce change in microvascular perfusion; however, it induced substantial transient parasympathetic activity withdrawal in patients with sickle cell disease, but not controls subjects. Marked periodic drops in peripheral microvascular perfusion, unrelated to hypoxia, were triggered by sighs in 11 of 11 patients with sickle cell and 8 of 11 control subjects. Although the sigh frequency was the same in both groups, the probability of a sigh inducing a perfusion drop was 78% in patients with sickle cell and 17% in control subjects (P < 0.001). Evidence for sigh-induced sympathetic nervous system dominance was seen in patients with sickle cell (P < 0.05), but was not significant in control subjects. Conclusions: These data demonstrate significant disruption of autonomic nervous system balance, with marked parasympathetic withdrawal in response to transient hypoxia. They draw attention to an enhanced autonomic nervous system–mediated sigh–vasoconstrictor response in patients with sickle cell that could increase red cell retention in the microvasculature, promoting vasoocclusion. PMID:21616995

Acylcarnitines as markers of exercise-associated fuel partitioning, xenometabolism, and potential signals to muscle afferent neurons.

PubMed

Zhang, Jie; Light, Alan R; Hoppel, Charles L; Campbell, Caitlin; Chandler, Carol J; Burnett, Dustin J; Souza, Elaine C; Casazza, Gretchen A; Hughen, Ronald W; Keim, Nancy L; Newman, John W; Hunter, Gary R; Fernandez, Jose R; Garvey, W Timothy; Harper, Mary-Ellen; Fiehn, Oliver; Adams, Sean H

2017-01-01

What is the central question of this study? Does improved metabolic health and insulin sensitivity following a weight-loss and fitness intervention in sedentary, obese women alter exercise-associated fuel metabolism and incomplete mitochondrial fatty acid oxidation (FAO), as tracked by blood acylcarnitine patterns? What is the main finding and its importance? Despite improved fitness and blood sugar control, indices of incomplete mitochondrial FAO increased in a similar manner in response to a fixed load acute exercise bout; this indicates that intramitochondrial muscle FAO is inherently inefficient and is tethered directly to ATP turnover. With insulin resistance or type 2 diabetes mellitus, mismatches between mitochondrial fatty acid fuel delivery and oxidative phosphorylation/tricarboxylic acid cycle activity may contribute to inordinate accumulation of short- or medium-chain acylcarnitine fatty acid derivatives [markers of incomplete long-chain fatty acid oxidation (FAO)]. We reasoned that incomplete FAO in muscle would be ameliorated concurrent with improved insulin sensitivity and fitness following a ∼14 week training and weight-loss intervention in obese, sedentary, insulin-resistant women. Contrary to this hypothesis, overnight-fasted and exercise-induced plasma C4-C14 acylcarnitines did not differ between pre- and postintervention phases. These metabolites all increased robustly with exercise (∼45% of pre-intervention peak oxygen consumption) and decreased during a 20 min cool-down. This supports the idea that, regardless of insulin sensitivity and fitness, intramitochondrial muscle β-oxidation and attendant incomplete FAO are closely tethered to absolute ATP turnover rate. Acute exercise also led to branched-chain amino acid acylcarnitine derivative patterns suggestive of rapid and transient diminution of branched-chain amino acid flux through the mitochondrial branched-chain ketoacid dehydrogenase complex. We confirmed our prior novel observation that a weight-loss/fitness intervention alters plasma xenometabolites [i.e. cis-3,4-methylene-heptanoylcarnitine and γ-butyrobetaine (a co-metabolite possibly derived in part from gut bacteria)], suggesting that host metabolic health regulated gut microbe metabolism. Finally, we considered whether acylcarnitine metabolites signal to muscle-innervating afferents; palmitoylcarnitine at concentrations as low as 1-10 μm activated a subset (∼2.5-5%) of these neurons ex vivo. This supports the hypothesis that in addition to tracking exercise-associated shifts in fuel metabolism, muscle acylcarnitines act as signals of exertion to short-loop somatosensory-motor circuits or to the brain. © 2016 The Authors. Experimental Physiology © 2016 The Physiological Society.

Physical exercise prevents short and long-term deficits on aversive and recognition memory and attenuates brain oxidative damage induced by maternal deprivation.

PubMed

Neves, Ben-Hur; Menezes, Jefferson; Souza, Mauren Assis; Mello-Carpes, Pâmela B

2015-12-01

It is known from previous research that physical exercise prevents long-term memory deficits induced by maternal deprivation in rats. But we could not assume similar effects of physical exercise on short-term memory, as short- and long-term memories are known to result from some different memory consolidation processes. Here we demonstrated that, in addition to long-term memory deficit, the short-term memory deficit resultant from maternal deprivation in object recognition and aversive memory tasks is also prevented by physical exercise. Additionally, one of the mechanisms by which the physical exercise influences the memory processes involves its effects attenuating the oxidative damage in the maternal deprived rats' hippocampus and prefrontal cortex.

Circulating T-Regulatory Cells, Exercise and the Elite Adolescent Swimmer

PubMed Central

Wilson, Lori D.; Zaldivar, Frank P.; Schwindt, Christina D.; Wang-Rodriguez, Jessica; Cooper, Dan M.

2014-01-01

Brief high intensity exercise induces peripheral leukocytosis possibly leading to a higher incidence of allergic symptoms in athletes undergoing excessive training. We studied the exercise-induced alternation of circulating Tregs and FoxP3+ Tregs due to acute intense swim exercise in elite swimmers (n = 22, 12 males, age = 15.4 yrs). Twelve had prior or current rhinitis or asthma and 10 had no current or prior allergy or asthma. Circulating Tregs increased significantly (p < .001) following exercise (pre = 133 ± 11.2, post = 196 ± 17.6) as did FoxP3+ cells (pre = 44, post = 64 cells/µl). Increases in Tregs and FoxP3+ Tregs occurred to the same extent in both groups of adolescent swimmers. PMID:19827454

The L-Z complexity of exercise-induced muscle fatigue based on acoustic myographye

NASA Astrophysics Data System (ADS)

Yijian, Min; Xinyuan, Liu; Tingting, Wang

2014-01-01

The mechanism of exercise fatigue was investigated during exercise using L-Z complexity of non-linear analysis. Muscle fatigue was induced in the sitting position by lifting the heel under a load. An acoustic myogram of the gastrocnemius was obtained until exhaustion. The different modes of the speed responses were calculated using the L-Z complexity method, which analyzes muscle fibers participation, while the exercise is in progress. The L-Z complexity decreased incrementally with decreases in muscle strength, reaching a minimum value when the muscle was exhausted. Our data indicate that the L-Z complexity method is easy to use and effective at revealing the dynamic characteristics and variations of exercise fatigue. This method could be used to monitor sports training.

Protective effects of aerobic exercise on acute lung injury induced by LPS in mice

PubMed Central

2012-01-01

Introduction The regular practice of physical exercise has been associated with beneficial effects on various pulmonary conditions. We investigated the mechanisms involved in the protective effect of exercise in a model of lipopolysaccharide (LPS)-induced acute lung injury (ALI). Methods Mice were divided into four groups: Control (CTR), Exercise (Exe), LPS, and Exercise + LPS (Exe + LPS). Exercised mice were trained using low intensity daily exercise for five weeks. LPS and Exe + LPS mice received 200 µg of LPS intratracheally 48 hours after the last physical test. We measured exhaled nitric oxide (eNO); respiratory mechanics; neutrophil density in lung tissue; protein leakage; bronchoalveolar lavage fluid (BALF) cell counts; cytokine levels in BALF, plasma and lung tissue; antioxidant activity in lung tissue; and tissue expression of glucocorticoid receptors (Gre). Results LPS instillation resulted in increased eNO, neutrophils in BALF and tissue, pulmonary resistance and elastance, protein leakage, TNF-alpha in lung tissue, plasma levels of IL-6 and IL-10, and IL-1beta, IL-6 and KC levels in BALF compared to CTR (P ≤0.02). Aerobic exercise resulted in decreases in eNO levels, neutrophil density and TNF-alpha expression in lung tissue, pulmonary resistance and elastance, and increased the levels of IL-6, IL-10, superoxide dismutase (SOD-2) and Gre in lung tissue and IL-1beta in BALF compared to the LPS group (P ≤0.04). Conclusions Aerobic exercise plays important roles in protecting the lungs from the inflammatory effects of LPS-induced ALI. The effects of exercise are mainly mediated by the expression of anti-inflammatory cytokines and antioxidants, suggesting that exercise can modulate the inflammatory-anti-inflammatory and the oxidative-antioxidative balance in the early phase of ALI. PMID:23078757

Individual variability in compensatory eating following acute exercise in overweight and obese women.

PubMed

Hopkins, Mark; Blundell, John E; King, Neil A

2014-10-01

While compensatory eating following acute aerobic exercise is highly variable, little is known about the underlying mechanisms that contribute to the alterations in exercise-induced eating behaviour. Overweight and obese women (body mass index=29.6±4.0 kg/m(2)) performed a bout of cycling individually tailored to expend 400 kcal (EX) or a time-matched no exercise control condition in a randomised, counter-balanced order. 60 min after the cessation of exercise, an ad libitum test meal was provided. Substrate oxidation and subjective appetite ratings were measured during exercise/time-matched rest, and during the period between the cessation of exercise and food consumption. While ad libitum energy intake (EI) did not differ between EX and the control condition (666.0±203.9 vs 664.6±174.4 kcal, respectively; ns), there was a marked individual variability in compensatory EI. The difference in EI between EX and the control condition ranged from -234.3 to 278.5 kcal. Carbohydrate oxidation during exercise was positively associated with postexercise EI, accounting for 37% of the variance in EI (r=0.57; p=0.02). These data indicate that the capacity of acute exercise to create a short-term energy deficit in overweight and obese women is highly variable. Furthermore, exercise-induced CHO oxidation can explain a part of the variability in acute exercise-induced compensatory eating. Postexercise compensatory eating could serve as an adaptive response to facilitate the restoration of carbohydrate balance. 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.

Brain-Derived Neurotrophic Factor Val66Met Human Polymorphism Impairs the Beneficial Exercise-Induced Neurobiological Changes in Mice.

PubMed

Ieraci, Alessandro; Madaio, Alessandro I; Mallei, Alessandra; Lee, Francis S; Popoli, Maurizio

2016-12-01

Several studies have shown that exercise improves cognitive functions and emotional behaviors. Positive effects of exercise have been associated with enhanced brain plasticity, adult hippocampal neurogenesis, and increased levels of brain-derived neurotrophic factor (BDNF). However, a substantial variability of individual response to exercise has been described, which may be accounted for by individual genetic variants. Here, we have assessed whether and how the common human BDNF Val66Met polymorphism influences the neurobiological effects modulated by exercise in BDNF Val66Met knock-in male mice. Wild-type (BDNF Val/Val ) and homozygous BDNF Val66Met (BDNF Met/Met ) male mice were housed in cages equipped with or without running wheels for 4 weeks. Changes in behavioral phenotype, hippocampal adult neurogenesis, and gene expression were evaluated in exercised and sedentary control mice. We found that exercise reduced the latency to feed in the novelty suppressed feeding and the immobility time in the forced swimming test in BDNF Val/Val but not in BDNF Met/Met mice. Hippocampal neurogenesis was reduced in BDNF Met/Met mice compared with BDNF Val/Val mice. BDNF Met/Met mice had lower basal BDNF protein levels in the hippocampus, which was not recovered following exercise. Moreover, exercise-induced expression of total BDNF, BDNF splice variants 1, 2, 4, 6 and fibronectin type III domain-containing protein 5 (FNDC5) mRNA levels were absent or reduced in the dentate gyrus of BDNF Met/Met mice. Exercise failed to enhance PGC-1α and FNDC5 mRNA levels in the BDNF Met/Met muscle. Overall these results indicate that, in adult male mice, the BDNF Val66Met polymorphism impairs the beneficial behavioral and neuroplasticity effects induced by physical exercise.

Blood flow patterns during incremental and steady-state aerobic exercise.

PubMed

Coovert, Daniel; Evans, LeVisa D; Jarrett, Steven; Lima, Carla; Lima, Natalia; Gurovich, Alvaro N

2017-05-30

Endothelial shear stress (ESS) is a physiological stimulus for vascular homeostasis, highly dependent on blood flow patterns. Exercise-induced ESS might be beneficial on vascular health. However, it is unclear what type of ESS aerobic exercise (AX) produces. The aims of this study are to characterize exercise-induced blood flow patterns during incremental and steady-state AX. We expect blood flow pattern during exercise will be intensity-dependent and bidirectional. Six college-aged students (2 males and 4 females) were recruited to perform 2 exercise tests on cycleergometer. First, an 8-12-min incremental test (Test 1) where oxygen uptake (VO2), heart rate (HR), blood pressure (BP), and blood lactate (La) were measured at rest and after each 2-min step. Then, at least 48-hr. after the first test, a 3-step steady state exercise test (Test 2) was performed measuring VO2, HR, BP, and La. The three steps were performed at the following exercise intensities according to La: 0-2 mmol/L, 2-4 mmol/L, and 4-6 mmol/L. During both tests, blood flow patterns were determined by high-definition ultrasound and Doppler on the brachial artery. These measurements allowed to determine blood flow velocities and directions during exercise. On Test 1 VO2, HR, BP, La, and antegrade blood flow velocity significantly increased in an intensity-dependent manner (repeated measures ANOVA, p<0.05). Retrograde blood flow velocity did not significantly change during Test 1. On Test 2 all the previous variables significantly increased in an intensity-dependent manner (repeated measures ANOVA, p<0.05). These results support the hypothesis that exercise induced ESS might be increased in an intensity-dependent way and blood flow patterns during incremental and steady-state exercises include both antegrade and retrograde blood flows.

Brain-Derived Neurotrophic Factor Val66Met Human Polymorphism Impairs the Beneficial Exercise-Induced Neurobiological Changes in Mice

PubMed Central

Ieraci, Alessandro; Madaio, Alessandro I; Mallei, Alessandra; Lee, Francis S; Popoli, Maurizio

2016-01-01

Several studies have shown that exercise improves cognitive functions and emotional behaviors. Positive effects of exercise have been associated with enhanced brain plasticity, adult hippocampal neurogenesis, and increased levels of brain-derived neurotrophic factor (BDNF). However, a substantial variability of individual response to exercise has been described, which may be accounted for by individual genetic variants. Here, we have assessed whether and how the common human BDNF Val66Met polymorphism influences the neurobiological effects modulated by exercise in BDNF Val66Met knock-in male mice. Wild-type (BDNFVal/Val) and homozygous BDNF Val66Met (BDNFMet/Met) male mice were housed in cages equipped with or without running wheels for 4 weeks. Changes in behavioral phenotype, hippocampal adult neurogenesis, and gene expression were evaluated in exercised and sedentary control mice. We found that exercise reduced the latency to feed in the novelty suppressed feeding and the immobility time in the forced swimming test in BDNFVal/Val but not in BDNFMet/Met mice. Hippocampal neurogenesis was reduced in BDNFMet/Met mice compared with BDNFVal/Val mice. BDNFMet/Met mice had lower basal BDNF protein levels in the hippocampus, which was not recovered following exercise. Moreover, exercise-induced expression of total BDNF, BDNF splice variants 1, 2, 4, 6 and fibronectin type III domain-containing protein 5 (FNDC5) mRNA levels were absent or reduced in the dentate gyrus of BDNFMet/Met mice. Exercise failed to enhance PGC-1α and FNDC5 mRNA levels in the BDNFMet/Met muscle. Overall these results indicate that, in adult male mice, the BDNF Val66Met polymorphism impairs the beneficial behavioral and neuroplasticity effects induced by physical exercise. PMID:27388329

Diagnosis and Management of Exercise-Induced Asthma.

ERIC Educational Resources Information Center

Rupp, Ned T.

1996-01-01

Exercise-induced asthma (EIA) affects 12-15% of the population. This comprehensive guide suggests that nearly all individuals with EIA can be active, highlighting both pharmacologic and nonpharmacologic management of asthma and stressing the importance of rigorous patient education in controlling underlying asthma and EIA. (SM)

Coping with Exercise-Induced Asthma in Sports.

ERIC Educational Resources Information Center

Katz, Roger M.

1987-01-01

This article reviews the history of research on exercise-induced asthma (EIA) and the pathophysiology of the condition, including its development and influencing factors. Four groups of drugs that are effective against EIA--theopyhlline, beta-adrenergic agents, cromolyn sodium, and anticholinergics--are discussed. (Author/CB)

EXERCISE-INDUCED PULMONARY HEMORRHAGE AFTER RUNNING A MARATHON

EPA Science Inventory

We report on a healthy 26-year-old male who had an exercise-induced pulmonary hemorrhage (EIPH) within 24 hours of running a marathon. There were no symptoms, abnormalities on exam, or radiographic infiltrates. He routinely participated in bronchoscopy research and the EIPH was e...

Update on the Mechanisms of Pulmonary Inflammation and Oxidative Imbalance Induced by Exercise.

PubMed

Araneda, O F; Carbonell, T; Tuesta, M

2016-01-01

The mechanisms involved in the generation of oxidative damage and lung inflammation induced by physical exercise are described. Changes in lung function induced by exercise involve cooling of the airways, fluid evaporation of the epithelial surface, increased contact with polluting substances, and activation of the local and systemic inflammatory response. The present work includes evidence obtained from the different types of exercise in terms of duration and intensity, the effect of both acute performance and chronic performance, and the influence of special conditions such as cold weather, high altitude, and polluted environments. Levels of prooxidants, antioxidants, oxidative damage to biomolecules, and cellularity, as well as levels of soluble mediators of the inflammatory response and its effects on tissues, are described in samples of lung origin. These samples include tissue homogenates, induced sputum, bronchoalveolar lavage fluid, biopsies, and exhaled breath condensate obtained in experimental protocols conducted on animal and human models. Finally, the need to simultaneously explore the oxidative/inflammatory parameters to establish the interrelation between them is highlighted.

Update on the Mechanisms of Pulmonary Inflammation and Oxidative Imbalance Induced by Exercise

PubMed Central

Araneda, O. F.; Carbonell, T.; Tuesta, M.

2016-01-01

The mechanisms involved in the generation of oxidative damage and lung inflammation induced by physical exercise are described. Changes in lung function induced by exercise involve cooling of the airways, fluid evaporation of the epithelial surface, increased contact with polluting substances, and activation of the local and systemic inflammatory response. The present work includes evidence obtained from the different types of exercise in terms of duration and intensity, the effect of both acute performance and chronic performance, and the influence of special conditions such as cold weather, high altitude, and polluted environments. Levels of prooxidants, antioxidants, oxidative damage to biomolecules, and cellularity, as well as levels of soluble mediators of the inflammatory response and its effects on tissues, are described in samples of lung origin. These samples include tissue homogenates, induced sputum, bronchoalveolar lavage fluid, biopsies, and exhaled breath condensate obtained in experimental protocols conducted on animal and human models. Finally, the need to simultaneously explore the oxidative/inflammatory parameters to establish the interrelation between them is highlighted. PMID:26881028

The preventive effect of nedocromil or furosemide alone or in combination on exercise-induced asthma in children.

PubMed

Novembre, E; Frongia, G; Lombardi, E; Veneruso, G; Vierucci, A

1994-08-01

Recent evidence suggests that inhaled nedocromil and furosemide are effective in preventing asthma by ultrasonically nebulized distilled water, allergen, and exercise. There are, however, no studies that compare the effects of these two drugs. The aim of this study was to investigate the effect of inhaled furosemide (30 mg), nedocromil (4 mg), the combination of these two drugs, and placebo aerosol in preventing exercise-induced asthma. Twenty-four children with exercise-induced asthma, aged 6 to 16 years, performed a treadmill test before and 20 minutes after a single dose of drug(s) in a double-blind trial. Lung function measurements were taken before drug administration, before the exercise test (20 minutes after drug administration), and then 2, 4, 6, 8, 10, 15, 20, and 30 minutes after the exercise test. Both active drugs performed significantly better than placebo. In fact, the exercise challenge resulted in a mean maximum fall in forced expiratory volume in 1 second of 28.46% +/- 13.84% after administration of placebo, but of only 15.42% +/- 8.35% after administration of nedocromil (p < 0.001) and of 11.37% +/- 9.14% after administration of furosemide (p < 0.001). When the two drugs were given together, there was a statistically significant additive effect because the mean maximum fall in forced expiratory volume in 1 second was 5.75% +/- 3.57% (nedocromil vs nedocromil + fluorsemide: p < 0.001; furosemide vs nedocromil + furosemide: p < 0.01). This study suggests that nedocromil and furosemide provide a comparable effect in preventing exercise-induced asthma in children. The combined administration of the two drugs significantly increases the protective effects, suggesting a potential therapeutic use.

The effects of post-extinction exercise on cocaine-primed and stress-induced reinstatement of cocaine seeking in rats.

PubMed

Ogbonmwan, Yvonne E; Schroeder, Jason P; Holmes, Philip V; Weinshenker, David

2015-04-01

Voluntary aerobic exercise has shown promise as a treatment for substance abuse, reducing relapse in cocaine-dependent people. Wheel running also attenuates drug-primed and cue-induced reinstatement of cocaine seeking in rats, an animal model of relapse. However, in most of these studies, wheel access was provided throughout cocaine self-administration and/or extinction and had effects on several parameters of drug seeking. Moreover, the effects of exercise on footshock stress-induced reinstatement have not been investigated. The purposes of this study were to isolate and specifically examine the protective effect of exercise on relapse-like behavior elicited by a drug prime or stress. Rats were trained to self-administer cocaine at a stable level, followed by extinction training. Once extinction criteria were met, rats were split into exercise (24 h, continuous access to running wheel) and sedentary groups for 3 weeks, after which, drug-seeking behavior was assessed following a cocaine prime or footshock. We also measured galanin messenger RNA (mRNA) in the locus coeruleus and A2 noradrenergic nucleus. Exercising rats ran ∼4-6 km/day, comparable to levels previously reported for rats without a history of cocaine self-administration. Post-extinction exercise significantly attenuated cocaine-primed, but not footshock stress-induced, reinstatement of cocaine seeking, and increased galanin mRNA expression in the LC but not A2. These results indicate that chronic wheel running can attenuate some forms of reinstatement, even when initiated after the cessation of cocaine self-administration, supporting the idea that voluntary exercise programs may help maintain abstinence in clinical populations.

Gene expression profiling in human skeletal muscle during recovery from eccentric exercise

PubMed Central

Mohoney, D. J.; Safdar, A.; Parise, G.; Melov, S.; Fu, Minghua; MacNeil, L.; Kaczor, J.; Payne, E. T.; Tarnopolsky, M. A.

2009-01-01

We used cDNA microarrays to screen for differentially expressed genes during recovery from exercise-induced muscle damage in humans. Male subjects (n = 4) performed 300 maximal eccentric contractions, and skeletal muscle biopsy samples were analyzed at 3 h and 48 h after exercise. In total, 113 genes increased 3 h postexercise, and 34 decreased. At 48 h postexercise, 59 genes increased and 29 decreased. On the basis of these data, we chose 19 gene changes and conducted secondary analyses using real-time RT-PCR from muscle biopsy samples taken from 11 additional subjects who performed an identical bout of exercise. Real-time RT-PCR analyses confirmed that exercise-induced muscle damage led to a rapid (3 h) increase in sterol response element binding protein 2 (SREBP-2), followed by a delayed (48 h) increase in the SREBP-2 gene targets Acyl CoA:cholesterol acyltransferase (ACAT)-2 and insulin-induced gene 1 (insig-1). The expression of the IL-1 receptor, a known regulator of SREBP-2, was also elevated after exercise. Taken together, these expression changes suggest a transcriptional program for increasing cholesterol and lipid synthesis and/or modification. Additionally, damaging exercise induced the expression of protein kinase H11, capping protein Z alpha (capZα), and modulatory calcineurin-interacting protein 1 (MCIP1), as well as cardiac ankryin repeat protein 1 (CARP1), DNAJB2, c-myc, and junD, each of which are likely involved in skeletal muscle growth, remodeling, and stress management. In summary, using DNA microarrays and RT-PCR, we have identified novel genes that respond to skeletal muscle damage, which, given the known biological functions, are likely involved in recovery from and/or adaptation to damaging exercise. PMID:18321953

Basic Guidelines to Introduce Electric Circuit Simulation Software in a General Physics Course

ERIC Educational Resources Information Center

Moya, A. A.

2018-01-01

The introduction of electric circuit simulation software for undergraduate students in a general physics course is proposed in order to contribute to the constructive learning of electric circuit theory. This work focuses on the lab exercises based on dc, transient and ac analysis in electric circuits found in introductory physics courses, and…

The influence of transient change of total body water on relative body fats based on three bioelectrical impedance analyses methods. Comparison between before and after exercise with sweat loss, and after drinking.

PubMed

Demura, S; Yamaji, S; Goshi, F; Nagasawa, Y

2002-03-01

The purpose of this study was to clarify the influence of change of total body water caused by exercise and drinking, on relative body fat (%BF) based on three bioelectrical impedance analyses (BIA) methods, between hand and foot (H-F), between hand and hand (H-H), and between foot and foot (F-F). The subjects were 30 Japanese healthy young adults aged 18 to 23 years (15 males, 15 females). Measurements were made three times for each BIA method; before and after exercise with sweat, and after drinking, and also twice according to the under water weighing (UW) method, before exercise and after drinking. A pedaling exercise, with a bicycle ergometer, was used for 60 minutes as the exercise. The relationship of %BF between the UW method and each BIA method was mid-range or more (r=0.765-0.839). However, %BF based on the H-F and F-F BIA methods were higher than that based on the UW method. After drinking, %BF of all the BIA methods were higher than the UW method. %BF of the BIA methods after exercise indicated values lower than those before exercise. %BF of the H-F and H-H BIA methods after drinking were a little higher than those before exercise, indicating that those measurements reflect a slight change of body water. It was demonstrated that %BF of any BIA method reflect the change of body water caused by exercise, sweating, and drinking.

New perspectives concerning feedback influences on cardiorespiratory control during rhythmic exercise and on exercise performance

PubMed Central

Dempsey, Jerome A

2012-01-01

The cardioaccelerator and ventilatory responses to rhythmic exercise in the human are commonly viewed as being mediated predominantly via feedforward ‘central command’ mechanisms, with contributions from locomotor muscle afferents to the sympathetically mediated pressor response. We have assessed the relative contributions of three types of feedback afferents on the cardiorespiratory response to voluntary, rhythmic exercise by inhibiting their normal ‘tonic’ activity in healthy animals and humans and in chronic heart failure. Transient inhibition of the carotid chemoreceptors during moderate intensity exercise reduced muscle sympathetic nerve activity (MSNA) and increased limb vascular conductance and blood flow; and reducing the normal level of respiratory muscle work during heavier intensity exercise increased limb vascular conductance and blood flow. These cardiorespiratory effects were prevented via ganglionic blockade and were enhanced in chronic heart failure and in hypoxia. Blockade of μ opioid sensitive locomotor muscle afferents, with preservation of central motor output via intrathecal fentanyl: (a) reduced the mean arterial blood pressure (MAP), heart rate and ventilatory responses to all steady state exercise intensities; and (b) during sustained high intensity exercise, reduced O2 transport, increased central motor output and end-exercise muscle fatigue and reduced endurance performance. We propose that these three afferent reflexes – probably acting in concert with feedforward central command – contribute significantly to preserving O2 transport to locomotor and to respiratory muscles during exercise. Locomotor muscle afferents also appear to provide feedback concerning the metabolic state of the muscle to influence central motor output, thereby limiting peripheral fatigue development. PMID:22826128

The mechanism of bradykinin-induced endothelium-dependent contraction and relaxation in the porcine interlobar renal artery

PubMed Central

Ihara, Eikichi; Hirano, Katsuya; Derkach, Dmitry N; Nishimura, Junji; Nawata, Hajime; Kanaide, Hideo

2000-01-01

The mechanism of endothelium-dependent regulation of vascular tone of bradykinin was investigated by simultaneously monitoring the changes in the cytosolic Ca2+ concentration and the force of smooth muscle in fura-2-loaded strips of the porcine renal artery with endothelium. During phenylephrine-induced sustained contraction, bradykinin (>3×10−9 M) caused endothelium-dependent triphasic changes in the force of the strips, composed of an initial relaxation, a subsequent transient contraction and a late sustained relaxation. At low concentrations (10−10–10−9 M), bradykinin caused an endothelium-dependent biphasic relaxation with no contraction. A thromboxane A2 (TXA2)/prostaglandin H2 (PGH2) receptor antagonist (10−5 M ONO-3708) completely inhibited, while a TXA2 synthase inhibitor (10−5 M OKY-046) only partially inhibited, the transient contraction induced by bradykinin. Under conditions where the bradykinin-induced contraction was inhibited by ONO-3708 during the phenylephrine-induced contraction, bradykinin induced only a transient relaxation in the presence of NΩ-nitro-L-arginine methyl ester (L-NAME). This transient relaxation was inhibited when the precontraction was initiated by phenylephrine plus 40 mM extracellular K+. The removal of L-NAME from this condition caused a partial reappearance of the initial relaxation and a complete reappearance of the sustained relaxation. In conclusion, bradykinin caused the endothelium-dependent triphasic regulation of vascular tone in the porcine renal artery. The concentrations of bradykinin required to induce a contraction was higher than that required to induce relaxation. Both TXA2 and PGH2 were involved in the bradykinin-induced contraction. The initial relaxation was mediated by nitric oxide and hyperpolarizing factors while the sustained relaxation depended on nitric oxide. PMID:10696094

Elevated central venous pressure: a consequence of exercise training-induced hypervolemia?

NASA Technical Reports Server (NTRS)

Convertino, V. A.; Mack, G. W.; Nadel, E. R.

1991-01-01

Resting blood volumes and arterial and central venous pressures (CVP) were measured in 14 men before and after exercise training to determine whether training-induced hypervolemia is accompanied by a change in total vascular capacitance. In addition, resting levels of plasma arginine vasopressin (AVP), atrial natriuretic peptide (ANP), aldosterone (Ald), and norepinephrine (NE) were measured. The same measurements were conducted in seven subjects who did not undergo exercise and acted as controls. Exercise training consisted of 10 wk of controlled cycle exercise for 30 min/day, 4 days/wk at 75-80% of maximal O2 uptake (VO2max). A training effect was verified by a 20% increase in VO2max, a resting bradycardia, and a 9% increase in blood volume. Mean arterial blood pressure was unaltered by exercise training, but resting CVP increased by 16% (P less than 0.05). The percent change in blood volume from before to after training was linearly related to the percent change in CVP (r = 0.903, P less than 0.05). As a consequence of elevations in both blood volume and CVP, the volume-to-pressure ratio was unchanged after exercise training. Plasma AVP, ANP, Ald, and NE were unaltered. Our results indicate that elevated CVP is a consequence of training-induced hypervolemia without alteration in total effective venous capacitance.

Muscle sympathetic nerve responses to physiological changes in prostaglandin production in humans

NASA Technical Reports Server (NTRS)

Doerzbacher, K. J.; Ray, C. A.

2001-01-01

Previous studies suggest that prostaglandins may contribute to exercise-induced increases in muscle sympathetic nerve activity (MSNA). To test this hypothesis, MSNA was measured at rest and during exercise before and after oral administration of ketoprofen, a cyclooxygenase inhibitor, or placebo. Twenty-one subjects completed two bouts of graded dynamic and isometric handgrip to fatigue. Each exercise bout was followed by 2 min of postexercise muscle ischemia. The second exercise bouts were performed after 60 min of rest in which 11 subjects were given ketoprofen (300 mg) and 10 subjects received a placebo. Ketoprofen significantly lowered plasma thromboxane B(2) in the drug group (from 36 +/- 6 to 22 +/- 3 pg/ml, P < 0.04), whereas thromboxane B(2) in the placebo group increased from 40 +/- 5 to 61 +/- 9 pg/ml from trial 1 to trial 2 (P < 0.008). Ketoprofen and placebo did not change sympathetic and cardiovascular responses to dynamic handgrip, isometric handgrip, and postexercise muscle ischemia. There was no relationship between thromboxane B(2) concentrations and MSNA or arterial pressure responses during both exercise modes. The data indicate that physiological increases or decreases in prostaglandins do not alter exercise-induced increases in MSNA and arterial pressure in humans. These findings suggest that contraction-induced metabolites other than prostaglandins mediate MSNA responses to exercise in humans.

Effect of Exercise and Calorie Restriction on Tissue Acylcarnitines, Tissue Desaturase Indices, and Fat Accumulation in Diet-Induced Obese Rats

PubMed Central

Gopalan, Venkatesh; Michael, Navin; Ishino, Seigo; Lee, Swee Shean; Yang, Adonsia Yating; Bhanu Prakash, K. N.; Yaligar, Jadegoud; Sadananthan, Suresh Anand; Kaneko, Manami; Zhou, Zhihong; Satomi, Yoshinori; Hirayama, Megumi; Kamiguchi, Hidenori; Zhu, Bin; Horiguchi, Takashi; Nishimoto, Tomoyuki; Velan, S. Sendhil

2016-01-01

Both exercise and calorie restriction interventions have been recommended for inducing weight-loss in obese states. However, there is conflicting evidence on their relative benefits for metabolic health and insulin sensitivity. This study seeks to evaluate the differential effects of the two interventions on fat mobilization, fat metabolism, and insulin sensitivity in diet-induced obese animal models. After 4 months of ad libitum high fat diet feeding, 35 male Fischer F344 rats were grouped (n = 7 per cohort) into sedentary control (CON), exercise once a day (EX1), exercise twice a day (EX2), 15% calorie restriction (CR1) and 30% calorie restriction (CR2) cohorts. Interventions were carried out over a 4-week period. We found elevated hepatic and muscle long chain acylcarnitines with both exercise and calorie restriction, and a positive association between hepatic long chain acylcarnitines and insulin sensitivity in the pooled cohort. Our result suggests that long chain acylcarnitines may not indicate incomplete fat oxidation in weight loss interventions. Calorie restriction was found to be more effective than exercise in reducing body weight. Exercise, on the other hand, was more effective in reducing adipose depots and muscle triglycerides, favorably altering muscle/liver desaturase activity and improving insulin sensitivity. PMID:27197769

Attenuation of endothelial dysfunction by exercise training in STZ-induced diabetic rats.

PubMed

Chakraphan, Daroonwan; Sridulyakul, Patarin; Thipakorn, Bundit; Bunnag, Srichitra; Huxley, Virginia H; Patumraj, Suthiluk

2005-01-01

The protective effects of exercise training on the diabetic-induced endothelial cell (EC) dysfunction were determined using intravital fluorescent microscopy. Male Sprague-Dawley rats were divided into three groups of control (Con), diabetes (DM), and diabetes with exercise--training (DM+Ex). Diabetes was induced by single intravenous injection of streptozotocin (STZ; 50 mg/kg BW). The exercise training protocol consisted of treadmill running, 5 times/week with the velocity of 13-15 m/min, 30 min/day periods for 12 and 24 weeks (wks). 24 wks after the STZ injection, blood glucose (BG), glycosylated hemoglobin (HbA1C), mean arterial blood pressure (MAP) and heart weight (HW) were significantly higher in DM rats (p < 0.001). However, DM+Ex rats had reduced the abnormalities of MAP (p < 0.01) and HW (p < 0.05) compared with DM rats. Furthermore, there was a significant decrease in heart rate (HR) of DM+Ex rats (p < 0.05) relative to Con rats. To examine the influence of exercise training on EC dysfunction, leukocyte-EC interactions in mesenteric venules and vascular reactivity responses to vasodilators in mesenteric arterioles were monitored by using intravital fluorescence microscopy. The diabetic state enhanced leukocyte adhesion in mesenteric postcapillary venules (p < 0.001). Moreover, an impaired vasodilatory response to the EC-dependent vasodilator, acetylcholine (Ach), not to sodium nitroprusside (SNP), was found in 12- and 24-wk diabetic rats (p < 0.01). The leukocyte adhesion and the impairment of EC-dependent vasodilation to Ach were attenuated by exercise training (p < 0.05). In addition, exercise training was also shown to have favorable preventive effects on hyperglycemia induced oxidative stress, as lower malondialdehyde (MDA) levels were observed from both groups of 12 and 24 weeks DM+Ex compared with DM (p < 0.01). In conclusion, our findings indicate that the endothelial dysfunction of diabetic rats could be characterized by increased leukocyte adhesion and impaired endothelium-dependent relaxation. Regular low intensity exercise training could improve both indices of endothelial dysfunction through amelioration of diabetic-induced oxidant/antioxidant levels. These findings support the notion that regular exercise training could be a fundamental form of therapy in preventing diabetic cardiovascular complications potentiated by endothelial dysfunction.

Effect of acute moderate exercise on induced inflammation and arterial function in older adults.

PubMed

Ranadive, Sushant Mohan; Kappus, Rebecca Marie; Cook, Marc D; Yan, Huimin; Lane, Abbi Danielle; Woods, Jeffrey A; Wilund, Kenneth R; Iwamoto, Gary; Vanar, Vishwas; Tandon, Rudhir; Fernhall, Bo

2014-04-01

Acute inflammation reduces flow-mediated vasodilatation and increases arterial stiffness in young healthy individuals. However, this response has not been studied in older adults. The aim of this study, therefore, was to evaluate the effect of acute induced systemic inflammation on endothelial function and wave reflection in older adults. Furthermore, an acute bout of moderate-intensity aerobic exercise can be anti-inflammatory. Taken together, we tested the hypothesis that acute moderate-intensity endurance exercise, immediately preceding induced inflammation, would be protective against the negative effects of acute systemic inflammation on vascular function. Fifty-nine healthy volunteers between 55 and 75 years of age were randomized to an exercise or a control group. Both groups received a vaccine (induced inflammation) and sham (saline) injection in a counterbalanced crossover design. Inflammatory markers, endothelial function (flow-mediated vasodilatation) and measures of wave reflection and arterial stiffness were evaluated at baseline and at 24 and 48 h after injections. There were no significant differences in endothelial function and arterial stiffness between the exercise and control group after induced inflammation. The groups were then analysed together, and we found significant differences in the inflammatory markers 24 and 48 h after induction of acute inflammation compared with sham injection. However, flow-mediated vasodilatation, augmentation index normalized for heart rate (AIx75) and β-stiffness did not change significantly. Our results suggest that acute inflammation induced by influenza vaccination did not affect endothelial function in older adults.

Repeated bouts of exhaustive exercise increase circulating cell free nuclear and mitochondrial DNA without development of tolerance in healthy men

PubMed Central

Stawski, Robert; Walczak, Konrad; Kosielski, Piotr; Meissner, Pawel; Budlewski, Tomasz; Padula, Gianluca; Nowak, Dariusz

2017-01-01

Objective Acute single strenuous exercise increases circulating cell free DNA (cf DNA). We tested whether three repeated bouts of exhaustive exercise induced the cf DNA response without development of tolerance in healthy men. Methods Eleven average-trained men (age 34.0±5.2 years, body mass index 26.2±3.1 kg/m2, maximal oxygen consumption—VO2max 49.6±4.5 ml/kg*min) performed three treadmill exercise tests to exhaustion at speed corresponding to 70% VO2max separated by 72 hours of resting. Blood was collected before and after each bout of exercise for determination of cell free nuclear and mitochondrial DNA (cf n-DNA, cf mt-DNA) by real-time PCR, selected markers of muscle damage, and blood cell count. Results Each bout induced the increase (p<0.05) in plasma cf n-DNA: from 3.4±1.4 to 38.5±27.5, from 4.1±3.3 to 48.5±26.2, and 3.1±1.6 to 53.8±39.9 ng/mL after the first, second, and third exercise, respectively. In a congruent way, cf mt-DNA rose significantly after the second (from 229±216 to 450±228*103 GE/mL) and third bout of exercise (from 173±120 to 462±314*103 GE/mL). Pre-exercise cf mt-DNA decreased (p<0.05) by 2-times (from 355±219 before the first bout to 173±120*103 GE/mL before the third bout) over the study period and were accompanied by significant increase in white blood cells, platelets, creatine kinase, creatinine and lactate after each bout. However, the exercise induced percentage increment of cf n-DNA was always many times higher than corresponding increments of the afore-mentioned markers at any occasion. Conclusions Repeated bouts of exhaustive exercise induced remarkable increase in circulating cf n-DNA without signs of tolerance development. Baseline cf mt-DNA decreased in response to series of strenuous exercise. Since percentage increments of cf n-DNA in response to exercise were many times higher than those observed for other markers, measurement of circulating cf n-DNA could be a sensitive tool for monitoring acute exercise effects in human body. PMID:28542490

Exercise training in obese older adults prevents increase in bone turnover and attenuates decrease in hip BMD induced by weight loss despite decline in bone-active hormones*

PubMed Central

Shah, Krupa; Armamento-Villareal, Reina; Parimi, Nehu; Chode, Suresh; Sinacore, David R.; Hilton, Tiffany N.; Napoli, Nicola; Qualls, Clifford; Villareal, Dennis T.

2011-01-01

Weight-loss therapy to improve health in obese older adults is controversial because it causes further bone loss. Therefore, it is recommended that weight-loss therapy should include an intervention to minimize bone loss such as exercise training (ET). The purpose of this study was to determine the independent and combined effects of weight loss and ET on bone metabolism in relation to bone mineral density (BMD) in obese older adults. One-hundred-seven older (age >65 yrs) obese (BMI ≥30 kg/m2) adults were randomly assigned to a control group, diet group, exercise group, and diet-exercise group for 1 year. Body weight decreased in the diet (−9.6%) and diet-exercise (−9.4%) groups, not in the exercise (−1%) and control (−0.2%) groups (between-group P<.001). However, despite comparable weight loss, bone loss at the total hip was relatively less in the diet-exercise group (−1.1%) than in the diet group (−2.6%), whereas BMD increased in the exercise group (1.5%) (between-group P<.001) Serum C-terminal telopeptide (CTX) and osteocalcin concentrations increased in the diet group (31% and 24%) while they decreased in the exercise group (−13% and −15%) (between-group P<.001). In contrast, similar to the control group, serum CTX and osteocalcin concentrations did not change in the diet-exercise group. Serum procollagen propeptide concentrations decreased in the exercise group (−15%) compared with the diet group (9%) (P=.04). Serum leptin and estradiol concentrations decreased in the diet (−25% and −15%) and diet-exercise (−38% and −13%) groups, not in the exercise and control groups (between-group P=.001). Multivariate analyses revealed that changes in lean body mass (β=.33), serum osteocalcin (β= −.24), and 1-RM strength (β=.23) were independent predictors of changes in hip BMD (all P<.05). In conclusion, the addition of ET to weight-loss therapy among obese older adults prevents weight-loss-induced increase in bone turnover and attenuates weight-loss-induced reduction in hip BMD despite weight-loss-induced decrease in bone-active hormones. PMID:21786319

Exercise-induced amenorrhea and bone health in the adolescent athlete.

PubMed

Warren, Michelle P; Chua, Abigail T

2008-01-01

Female participation in high school athletics has increased 800% in the last 30 years. The problem of exercise-induced amenorrhea was initially thought to be analogous to hypoestrogenism, but recent studies suggest that nutritional issues underlie most of the pathophysiology and that the mechanism is different from that seen in the primary hypogonadal state. Exercise-induced amenorrhea can be an indicator of an energy drain, and the presence of the other components of the female athlete triad-bone density loss and eating disorders-must be determined as well. Addressing skeletal problems related to nutritional and hormonal deficiencies in this population is of very high priority.

Autophagy activation, not peroxisome proliferator-activated receptor γ coactivator 1α, may mediate exercise-induced improvements in glucose handling during diet-induced obesity.

PubMed

Rosa-Caldwell, Megan E; Brown, Jacob L; Lee, David E; Blackwell, Thomas A; Turner, Kyle W; Brown, Lemuel A; Perry, Richard A; Haynie, Wesley S; Washington, Tyrone A; Greene, Nicholas P

2017-09-01

What is the central question of this study? What are the individual and combined effects of muscle-specific peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) overexpression and physical activity during high-fat feeding on glucose and exercise tolerance? What is the main finding and its importance? Our main finding is that muscle-specific PGC-1α overexpression provides no protection against lipid-overload pathologies nor does it enhance exercise adaptations. Instead, physical activity, regardless of PGC-1α content, protects against high-fat diet-induced detriments. Activation of muscle autophagy was correlated with exercise protection, suggesting that autophagy might be a mediating factor for exercise-induced protection from lipid overload. The prevalence of glucose intolerance is alarmingly high. Efforts to promote mitochondrial biogenesis through peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) to mitigate glucose intolerance have been controversial. However, physical activity remains a primary means to alleviate the condition. The aim of this study was to determine the combined effects of muscle-specific overexpression of PGC-1α and physical activity on glucose handling during diet-induced obesity. Wild-type (WT, ∼20) and PGC-1α muscle transgenic (MCK-PGC-1α, ∼20) mice were given a Western diet (WD) at 8 weeks age and allowed to consume food ab libitum throughout the study. At 12 weeks of age, all animals were divided into sedentary (SED) or voluntary wheel running (VWR) interventions. At 7, 11 and 15 weeks of age, animals underwent glucose tolerance tests (GTT) and graded exercise tests (GXT). At 16 weeks of age, tissues were collected. At 11 weeks, the MCK-PGC-1α animals had 50% greater glucose tolerance integrated area under the curve compared with WT. However, at 15 weeks, SED animals also had greater GTT integrated area under the curve compared with VWR, regardless of genotype; furthermore, SED animals demonstrated reduced exercise capacity compared with earlier time points, which was not seen in VWR animals. Voluntary distance run per day was correlated with GTT in VWR-WT, but not VWR-MCK-PGC-1α mice. Voluntary wheel running and genotype independently resulted in a greater LC3II/LC3I ratio, suggesting enhanced autophagosome formation, which was correlated with exercise-induced improvements in GTT. In conclusion, artificially increasing mitochondrial content does not protect from lipid-induced pathologies nor does it augment exercise adaptations. Physical activity ameliorates the effects of lipid overload-induced glucose intolerance, an effect that appears to be related to enhanced activation of autophagy. © 2017 The Authors. Experimental Physiology © 2017 The Physiological Society.

Wearing lower-body compression garment with medium pressure impaired exercise-induced performance decrement during prolonged running

PubMed Central

Mizuno, Sahiro

2017-01-01

Objective To investigate the effect of wearing a lower body compression garment (CG) exerting different pressure levels during prolonged running on exercise-induced muscle damage and the inflammatory response. Methods Eight male participants completed three exercise trials in a random order. The exercise consisted of 120 min of uphill running at 60% of VO2max. The exercise trials included 1) wearing a lower-body CG with 30 mmHg pressure [HIGH]; 2) wearing a lower-body CG with 15 mmHg pressure [MED]; and 3) wearing a lower-body garment with < 5 mmHg pressure [CON]. Heart rate (HR), and rate of perceived exertion for respiration and legs were monitored continuously during exercise. Time-course change in jump height was evaluated before and immediately after exercise. Blood samples were collected to determine blood glucose, lactate, serum creatine kinase, myoglobin, free fatty acids, glycerol, cortisol, and plasma interleukin-6 (IL-6) concentrations before exercise, 60 min of the 120 min exercise period, immediately after exercise, and 60 min after exercise. Results Jump height was significantly higher immediately after the exercise in the MED trial compared with that in the HIGH trial (P = 0.04). Mean HR during the 120 min exercise was significantly lower in the MED trial (162 ± 4 bpm) than that in the CON trial (170 ± 4 bpm, P = 0.01). Plasma IL-6 concentrations increased significantly with exercise in all trials, but the area under the curve during exercise was significantly lower in the MED trial (397 ± 58 pg/ml·120 min) compared with that in the CON trial (670 ± 86 pg/ml·120 min, P = 0.04). Conclusion Wearing a lower body CG exerting medium pressure (approximately 15 mmHg) significantly attenuated decrease in jump performance than that with wearing a lower body CG exerting high pressure (approximately 30 mmHg). Furthermore, exercise-induced increases in HR and the inflammatory response were significantly smaller with CG exerted 15mmHg than that with garment exerted < 5 mmHg. PMID:28562650

Arm and Intensity-Matched Leg Exercise Induce Similar Inflammatory Responses.

PubMed

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

2016-06-01

The amount of active muscle mass can influence the acute inflammatory response to exercise, associated with reduced risk for chronic disease. This may affect those restricted to upper body exercise, for example, due to injury or disability. The purpose of this study was to compare the inflammatory responses for arm exercise and intensity-matched leg exercise. Twelve male individuals performed three 45-min constant load exercise trials after determination of peak oxygen uptake for arm exercise (V˙O2peak A) and cycling (V˙O2peak C): 1) arm cranking exercise at 60% V˙O2peak A, 2) moderate cycling at 60% V˙O2peak C, and 3) easy cycling at 60% V˙O2peak A. Cytokine, adrenaline, and flow cytometric analysis of monocyte subsets were performed before and up to 4 h postexercise. Plasma IL-6 increased from resting concentrations in all trials; however, postexercise concentrations were higher for arm exercise (1.73 ± 1.04 pg·mL) and moderate cycling (1.73 ± 0.95 pg·mL) compared with easy cycling (0.87 ± 0.41 pg·mL; P < 0.04). Similarly, the plasma IL-1ra concentration in the recovery period was higher for arm exercise (325 ± 139 pg·mL) and moderate cycling (316 ± 128 pg·mL) when compared with easy cycling (245 ± 77 pg·mL, P < 0.04). Arm exercise and moderate cycling induced larger increases in monocyte numbers and larger increases of the classical monocyte subset in the recovery period than easy cycling (P < 0.05). The postexercise adrenaline concentration was lowest for easy cycling (P = 0.04). Arm exercise and cycling at the same relative exercise intensity induces a comparable acute inflammatory response; however, cycling at the same absolute oxygen uptake as arm exercise results in a blunted cytokine, monocyte, and adrenaline response. Relative exercise intensity appears to be more important to the acute inflammatory response than modality, which is of major relevance for populations restricted to upper body exercise.

Examination of mechanisms (E-MECHANIC) of exercise-induced weight compensation: study protocol for a randomized controlled trial.

PubMed

Myers, Candice A; Johnson, William D; Earnest, Conrad P; Rood, Jennifer C; Tudor-Locke, Catrine; Johannsen, Neil M; Cocreham, Shannon; Harris, Melissa; Church, Timothy S; Martin, Corby K

2014-06-07

Weight loss induced only by exercise is frequently less than expected, possibly because of compensatory changes in energy intake and/or energy expenditure. The purpose of the Examination of Mechanisms (E-MECHANIC) of Exercise-Induced Weight Compensation trial is to examine whether increased energy intake and/or reduced spontaneous activity or energy expenditure (outside of structured exercise) account for the less than expected, exercise-associated weight loss. E-MECHANIC is a three-arm, 6-month randomized (1:1:1) controlled trial. The two intervention arms are exercise doses that reflect current recommendations for (1) general health (8 kcal/kg body weight per week (8 KKW), about 900 kcal/wk) and (2) weight loss (20 KKW, about 2,250 kcal/wk). The third arm, a nonexercise control group, will receive health information only. The sample will include a combined total of 198sedentary, overweight or obese (body mass index: ≥25 kg/m² to ≤45 kg/m²) men and women ages 18 to 65 years. The exercise dose will be supervised and tightly controlled in an exercise training laboratory. The primary outcome variables are energy intake, which will be measured using doubly labeled water (adjusted for change in energy stores) and laboratory-based food intake tests, and the discrepancy between expected weight loss and observed weight loss. Secondary outcomes include changes in resting metabolic rate (adjusted for change in body mass), activity levels (excluding structured exercise) and body composition. In an effort to guide the development of future interventions, the participants will be behaviorally phenotyped and defined as those who do compensate (that is, fail to lose the amount of weight expected) or do not compensate (that is, lose the amount of weight expected or more). In this study, we will attempt to identify underlying mechanisms to explain why exercise elicits less weight loss than expected. This information will guide the development of interventions to increase exercise-induced weight loss and maximize weight loss retention and related health benefits. ClinicalTrials.gov ID: NCT01264406 (registration date: 20 December 2010).

The Impaired Function of Macrophages Induced by Strenuous Exercise Could Not Be Ameliorated by BCAA Supplementation

PubMed Central

Xiao, Weihua; Chen, Peijie; Liu, Xiaoguang; Zhao, Linlin

2015-01-01

The aim of this study was to evaluate the effect of strenuous exercise on the functions of peritoneal macrophages in rats and to test the hypothesis that branched-chain amino acid (BCAA) supplementation will be beneficial to the macrophages of rats from strenuous exercise. Forty male Wistar rats were randomly divided into five groups: (C) Control, E) Exercise, (E1) Exercise with one week to recover, (ES) Exercise + Supplementation and (ES1) Exercise + Supplementation with 1 week to recover. All rats except those of the sedentary control were subjected to four weeks of strenuous exercise. Blood hemoglobin, serum testosterone and BCAA levels were tested. Peritoneal macrophages functions were also determined at the same time. The data showed that hemoglobin, testosterone, BCAA levels, and body weight in group E decreased significantly as compared with that of group C. Meanwhile, phagocytosis capacity (decreased by 17.07%, p = 0.031), reactive oxygen species (ROS) production (decreased by 26%, p = 0.003) and MHC II mRNA (decreased by 22%, p = 0.041) of macrophages decreased in the strenuous exercise group as compared with group C. However, the chemotaxis of macrophages did not change significantly. In addition, BCAA supplementation could slightly increase the serum BCAA levels of rats from strenuous exercise (increased by 6.70%, p > 0.05). Moreover, the body weight, the blood hemoglobin, the serum testosterone and the function of peritoneal macrophages in group ES did not change significantly as compared with group E. These results suggest that long-term intensive exercise impairs the function of macrophages, which is essential for microbicidal capability. This may represent a novel mechanism of immunosuppression induced by strenuous exercise. Moreover, the impaired function of macrophage induced by strenuous exercise could not be ameliorated by BCAA supplementation in the dosing and timing used for this study. PMID:26506374

The Impaired Function of Macrophages Induced by Strenuous Exercise Could Not Be Ameliorated by BCAA Supplementation.

PubMed

Xiao, Weihua; Chen, Peijie; Liu, Xiaoguang; Zhao, Linlin

2015-10-21

The aim of this study was to evaluate the effect of strenuous exercise on the functions of peritoneal macrophages in rats and to test the hypothesis that branched-chain amino acid (BCAA) supplementation will be beneficial to the macrophages of rats from strenuous exercise. Forty male Wistar rats were randomly divided into five groups: (C) Control, E) Exercise, (E1) Exercise with one week to recover, (ES) Exercise + Supplementation and (ES1) Exercise + Supplementation with 1 week to recover. All rats except those of the sedentary control were subjected to four weeks of strenuous exercise. Blood hemoglobin, serum testosterone and BCAA levels were tested. Peritoneal macrophages functions were also determined at the same time. The data showed that hemoglobin, testosterone, BCAA levels, and body weight in group E decreased significantly as compared with that of group C. Meanwhile, phagocytosis capacity (decreased by 17.07%, p = 0.031), reactive oxygen species (ROS) production (decreased by 26%, p = 0.003) and MHC II mRNA (decreased by 22%, p = 0.041) of macrophages decreased in the strenuous exercise group as compared with group C. However, the chemotaxis of macrophages did not change significantly. In addition, BCAA supplementation could slightly increase the serum BCAA levels of rats from strenuous exercise (increased by 6.70%, p > 0.05). Moreover, the body weight, the blood hemoglobin, the serum testosterone and the function of peritoneal macrophages in group ES did not change significantly as compared with group E. These results suggest that long-term intensive exercise impairs the function of macrophages, which is essential for microbicidal capability. This may represent a novel mechanism of immunosuppression induced by strenuous exercise. Moreover, the impaired function of macrophage induced by strenuous exercise could not be ameliorated by BCAA supplementation in the dosing and timing used for this study.