Preventive strength training improves working ergonomics during welding.

PubMed

Krüger, Karsten; Petermann, Carmen; Pilat, Christian; Schubert, Emil; Pons-Kühnemann, Jörn; Mooren, Frank C

2015-01-01

To investigate the effect of a preventive strength training program on cardiovascular, metabolic and muscular strains during welding. Welders are one of the occupation groups which typically have to work in extended forced postures which are known to be an important reason for musculoskeletal disorders. Subjects (exercise group) accomplished a 12-week strength training program, while another group served as controls (control group). Pre and post training examinations included the measurements of the one repetition maximum and an experimental welding test. Local muscle activities were analysed by surface electromyography. Furthermore, heart rate, blood pressure, lactate and rating of perceived exertion were examined. In the exercise group, strength training lead to a significant increase of one repetition maximum in all examined muscles (p<.05). During the experimental welding test muscle activities of trunk and shoulder muscles and arm muscles were significantly reduced in the exercise group after intervention (p<.05). While no changes of neither cardiovascular nor metabolic parameters were found, subjects of the exercise group rated a significantly decreased rate of perceived exertion welding (p<.05). Effects of strength training can be translated in an improved working ergonomics and tolerance against the exposure to high physical demands at work.

Exercise, an Active Lifestyle, and Obesity. Making the Exercise Prescription Work.

ERIC Educational Resources Information Center

Andersen, Ross E.

1999-01-01

An active lifestyle is important in helping overweight people both lose and manage their weight. Exercise has many health benefits beyond weight control. The traditional exercise prescription of regular bouts of continuous vigorous exercise may need modification to increase rates of adoption and compliance, with people needing encouragement to…

Low-level carbon monoxide exposure and work capacity at 1600 meters

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

Weiser, P.C.; Cropp, G.J.A.; Morrill, C.G.

At sea level, low-level carbon monoxide (CO) exposure impairs exercise performance. To determine if altitude residence at 1600 m augments this CO effect, two studies of graded treadmill work capacity were done. The Initial Study investigated nine, non-smoking male subjects breathing either filtered air (FA) or 28 ppm CO in filtered air. End-exercise carboxyhemoglobin (HbCO) levels averaged 0.9 %HbCO breathing FA and 4.7 %HbCO breathing CO. Total work performance and aerobic work capacity were reduced. Work heart rate was elevated, and post-exercise left ventricular ejection time breathing CO did not shorten to the same degree as with FA exposure. COmore » exposure resulted in a lower anaerobic threshold, and a greater minute ventilation occurred at work rates heavier than the anaerobic threshold due to an increased blood lactate level. The Dose-Response Study exposed twelve subjects to FA or CO such that the end-exercise HbCO levels were 0.7, 3.5, 5.4 and 8.7 %HbCO. Exercise performance and aerobic work capacity were impaired in proportion to the CO exposure. In both studies, maximal cardio-pulmonary responses were not different, but submaximal exercise changes were elevated breathing CO. Thus, in healthy young men residing near 1600 m, an increase in low-level CO exposure produced a linear decrement in maximal aerobic performance similar to that reported at sea level.« less

Symptom-limited exercise testing causes sustained diastolic dysfunction in patients with coronary disease and low effort tolerance.

PubMed

Fragasso, G; Benti, R; Sciammarella, M; Rossetti, E; Savi, A; Gerundini, P; Chierchia, S L

1991-05-01

Exercise stress testing is routinely used for the noninvasive assessment of coronary artery disease and is considered a safe procedure. However, the provocation of severe ischemia might potentially cause delayed recovery of myocardial function. To investigate the possibility that maximal exercise testing could induce prolonged impairment of left ventricular function, 15 patients with angiographically proved coronary disease and 9 age-matched control subjects with atypical chest pain and normal coronary arteries were studied. Radionuclide ventriculography was performed at rest, at peak exercise, during recovery and 2 and 7 days after exercise. Ejection fraction, peak filling and peak emptying rates and left ventricular wall motion were analyzed. All control subjects had a normal exercise test at maximal work loads and improved left ventricular function on exercise. Patients developed 1 mm ST depression at 217 +/- 161 s at a work load of 70 +/- 30 W and a rate-pressure product of 18,530 +/- 4,465 mm Hg x beats/min. Although exercise was discontinued when angina or equivalent symptoms occurred, in all patients diagnostic ST depression (greater than or equal to 1 mm) developed much earlier than symptoms. Predictably, at peak exercise patients showed a decrease in ejection fraction and peak emptying and filling rates. Ejection fraction and peak emptying rate normalized within the recovery period, whereas peak filling rate remained depressed throughout recovery (p less than 0.002) and was still reduced 2 days after exercise (p less than 0.02). In conclusion, in patients with severe impairement of coronary flow reserve, maximal exercise may cause sustained impairement of diastolic function.(ABSTRACT TRUNCATED AT 250 WORDS)

The ventilatory anaerobic threshold is related to, but is lower than, the critical power, but does not explain exercise tolerance at this workrate.

PubMed

Okudan, N; Gökbel, H

2006-03-01

The aim of the present study was to investigate the relationships between critical power (CP), maximal aerobic power and the anaerobic threshold and whether exercise time to exhaustion and work at the CP can be used as an index in the determination of endurance. An incremental maximal cycle exercise test was performed on 30 untrained males aged 18-22 years. Lactate analysis was carried out on capillary blood samples at every 2 minutes. From gas exchange parameters and heart rate and lactate values, ventilatory anaerobic thresholds, heart rate deflection point and the onset of blood lactate accumulation were calculated. CP was determined with linear work-time method using 3 loads. The subjects exercised until they could no longer maintain a cadence above 24 rpm at their CP and exercise time to exhaustion was determined. CP was lower than the power output corresponding to VO2max, higher than the power outputs corresponding to anaerobic threshold. CP was correlated with VO2max and anaerobic threshold. Exercise time to exhaustion and work at CP were not correlated with VO2max and anaerobic threshold. Because of the correlations of the CP with VO2max and anaerobic threshold and no correlation of exercise time to exhaustion and work at the CP with these parameters, we conclude that exercise time to exhaustion and work at the CP cannot be used as an index in the determination of endurance.

Influence of respiratory muscle work on VO(2) and leg blood flow during submaximal exercise.

PubMed

Wetter, T J; Harms, C A; Nelson, W B; Pegelow, D F; Dempsey, J A

1999-08-01

The work of breathing (W(b)) normally incurred during maximal exercise not only requires substantial cardiac output and O(2) consumption (VO(2)) but also causes vasoconstriction in locomotor muscles and compromises leg blood flow (Q(leg)). We wondered whether the W(b) normally incurred during submaximal exercise would also reduce Q(leg). Therefore, we investigated the effects of changing the W(b) on Q(leg) via thermodilution in 10 healthy trained male cyclists [maximal VO(2) (VO(2 max)) = 59 +/- 9 ml. kg(-1). min(-1)] during repeated bouts of cycle exercise at work rates corresponding to 50 and 75% of VO(2 max). Inspiratory muscle work was 1) reduced 40 +/- 6% via a proportional-assist ventilator, 2) not manipulated (control), or 3) increased 61 +/- 8% by addition of inspiratory resistive loads. Increasing the W(b) during submaximal exercise caused VO(2) to increase; decreasing the W(b) was associated with lower VO(2) (DeltaVO(2) = 0.12 and 0.21 l/min at 50 and 75% of VO(2 max), respectively, for approximately 100% change in W(b)). There were no significant changes in leg vascular resistance (LVR), norepinephrine spillover, arterial pressure, or Q(leg) when W(b) was reduced or increased. Why are LVR, norepinephrine spillover, and Q(leg) influenced by the W(b) at maximal but not submaximal exercise? We postulate that at submaximal work rates and ventilation rates the normal W(b) required makes insufficient demands for VO(2) and cardiac output to require any cardiovascular adjustment and is too small to activate sympathetic vasoconstrictor efferent output. Furthermore, even a 50-70% increase in W(b) during submaximal exercise, as might be encountered in conditions where ventilation rates and/or inspiratory flow resistive forces are higher than normal, also does not elicit changes in LVR or Q(leg).

A structure-function analysis of the left ventricle

PubMed Central

Meyer, Leith C. R.; Fuller, Andrea; Haw, Anna; Mitchell, Duncan; Farrell, Anthony P.; Costello, Mary-Ann; Izwan, Adian; Badenhorst, Margaret; Maloney, Shane K.

2016-01-01

This study presents a structure-function analysis of the mammalian left ventricle and examines the performance of the cardiac capillary network, mitochondria, and myofibrils at rest and during simulated heavy exercise. Left ventricular external mechanical work rate was calculated from cardiac output and systemic mean arterial blood pressure in resting sheep (Ovis aries; n = 4) and goats (Capra hircus; n = 4) under mild sedation, followed by perfusion-fixation of the left ventricle and quantification of the cardiac capillary-tissue geometry and cardiomyocyte ultrastructure. The investigation was then extended to heavy exercise by increasing cardiac work according to published hemodynamics of sheep and goats performing sustained treadmill exercise. Left ventricular work rate averaged 0.017 W/cm3 of tissue at rest and was estimated to increase to ∼0.060 W/cm3 during heavy exercise. According to an oxygen transport model we applied to the left ventricular tissue, we predicted that oxygen consumption increases from 195 nmol O2·s−1·cm−3 of tissue at rest to ∼600 nmol O2·s−1·cm−3 during heavy exercise, which is within 90% of the oxygen demand rate and consistent with work remaining predominantly aerobic. Mitochondria represent 21-22% of cardiomyocyte volume and consume oxygen at a rate of 1,150 nmol O2·s−1·cm−3 of mitochondria at rest and ∼3,600 nmol O2·s−1·cm−3 during heavy exercise, which is within 80% of maximum in vitro rates and consistent with mitochondria operating near their functional limits. Myofibrils represent 65–66% of cardiomyocyte volume, and according to a Laplacian model of the left ventricular chamber, generate peak fiber tensions in the range of 50 to 70 kPa at rest and during heavy exercise, which is less than maximum tension of isolated cardiac tissue (120–140 kPa) and is explained by an apparent reserve capacity for tension development built into the left ventricle. PMID:27586835

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.

Preferred Exertion across Three Common Modes of Exercise Training.

ERIC Educational Resources Information Center

Glass, Stephen C.; Chvala, Angela M.

2001-01-01

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

Heart Rate Monitors

NASA Technical Reports Server (NTRS)

1990-01-01

Under a NASA grant, Dr. Robert M. Davis and Dr. William M. Portnoy came up with a new type of electrocardiographic electrode that would enable long term use on astronauts. Their invention was an insulated capacitive electrode constructed of a thin dielectric film. NASA subsequently licensed the electrode technology to Richard Charnitski, inventor of the VersaClimber, who founded Heart Rate, Inc., to further develop and manufacture personal heart monitors and to produce exercise machines using the technology for the physical fitness, medical and home markets. Same technology is on both the Home and Institutional Model VersaClimbers. On the Home Model an infrared heart beat transmitter is worn under exercise clothing. Transmitted heart rate is used to control the work intensity on the VersaClimber using the heart rate as the speedometer of the exercise. This offers advantages to a full range of users from the cardiac rehab patient to the high level physical conditioning of elite athletes. The company manufactures and markets five models of the 1*2*3 HEART RATE monitors that are used wherever people exercise to accurately monitor their heart rate. Company is developing a talking heart rate monitor that works with portable headset radios. A version of the heart beat transmitter will be available to the manufacturers of other aerobic exercise machines.

Cardiorespiratory response to exercise after renal sympathetic denervation in patients with resistant hypertension.

PubMed

Ukena, Christian; Mahfoud, Felix; Kindermann, Ingrid; Barth, Christine; Lenski, Matthias; Kindermann, Michael; Brandt, Mathias C; Hoppe, Uta C; Krum, Henry; Esler, Murray; Sobotka, Paul A; Böhm, Michael

2011-09-06

This study sought to investigate the effects of interventional renal sympathetic denervation (RD) on cardiorespiratory response to exercise. RD reduces blood pressure at rest in patients with resistant hypertension. We enrolled 46 patients with therapy-resistant hypertension as extended investigation of the Symplicity HTN-2 (Renal Denervation With Uncontrolled Hypertension) trial. Thirty-seven patients underwent bilateral RD and 9 patients were assigned to the control group. Cardiopulmonary exercise tests were performed at baseline and 3-month follow-up. In the RD group, compared with baseline examination, blood pressure at rest and at maximum exercise after 3 months was significantly reduced by 31 ± 13/9 ± 13 mm Hg (p < 0.0001) and by 21 ± 20/5 ± 14 mm Hg (p < 0.0001), respectively. Achieved work rate increased by 5 ± 13 W (p = 0.029) whereas peak oxygen uptake remained unchanged. Blood pressure 2 min after exercise was significantly reduced by 29 ± 17/8 ± 15 mm Hg (p < 0.001 for systolic blood pressure; p = 0.002 for diastolic blood pressure). Heart rate at rest decreased after RD (4 ± 11 beats/min; p = 0.028), whereas maximum heart rate and heart rate increase during exercise were not different. Heart rate recovery improved significantly by 4 ± 7 beats/min after renal denervation (p = 0.009). In the control group, there were no significant changes in blood pressure, heart rate, maximum work rate, or ventilatory parameters after 3 months. RD reduces blood pressure during exercise without compromising chronotropic competence in patients with resistant hypertension. Heart rate at rest decreased and heart rate recovery improved after the procedure. (Renal Denervation With Uncontrolled Hypertension; [Symplicity HTN-2]; NCT00888433). Copyright © 2011 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

The relationship between biventricular myocardial performance and metabolic parameters during incremental exercise and recovery in healthy adolescents

PubMed Central

Gowing, Lucy; Forsey, Jonathan; Ramanujam, Paramanantham; Miller, Felicity; Stuart, A Graham; Williams, Craig A.

2015-01-01

Background left ventricular (LV) and right ventricular (RV) myocardial reserve during exercise in adolescents has not been directly characterized. The aim of this study was to quantify myocardial performance response to exercise by using two-dimensional (2-D) speckle tracking echocardiography and describe the relationship between myocardial reserve, respiratory, and metabolic exercise parameters. A total of 23 healthy boys and girls (mean age 13.2 ± 2.7 yr; stature 159.1 ± 16.4 cm; body mass 49.5 ± 16.6 kg; BSA 1.47 ± 0.33 m2) completed an incremental cardiopulmonary exercise test (25 W·3 min increments) with simultaneous acquisition of 2-D transthoracic echocardiography at rest, each exercise stage up to 100 W, and in recovery at 2 min and 10 min. Two-dimensional LV (LV Sl) and RV (RV Sl) longitudinal strain and LV circumferential strain (LV Sc) were analyzed to define the relationship between myocardial performance reserve and metabolic exercise parameters. Participants achieved a peak oxygen uptake (V̇o2peak) of 40.6 ± 8.9 ml·kg−1·min−1 and a work rate of 154 ± 42 W. LV Sl and LV Sc and RV Sl increased significantly across work rates (P < 0.05). LV Sl during exercise was significantly correlated to resting strain, V̇o2peak, oxygen pulse, and work rate (0.530 ≤ r ≤ 0.784, P < 0.05). This study identifies a positive and moderate relationship between LV and RV myocardial performance and metabolic parameters during exercise by using a novel methodology. Relationships detected present novel data directly describing myocardial adaptation at different stages of exercise and recovery that in the future can help directly assess cardiac reserve in patients with cardiac pathology. PMID:26475589

[Cardiovascular recovery during intermittent exercise in highly-adherent partic pants with hypertension and type 2 diabetes mellitus].

PubMed

Cano-Montoya, Johnattan; Álvarez, Cristian; Martínez, Cristian; Salas, Andrés; Sade, Farid; Ramírez-Campillo, Rodrigo

2016-09-01

Despite the evidence supporting metabolic benefits of high intensity interval exercise (HIIT), there is little information about the cardiovascular response to this type of exercise in patients with type 2 diabetes (T2D) and hypertension (HTA). To analyze the changes in heart rate at rest, at the onset and at the end of each interval of training, after twelve weeks of a HIIT program in T2D and HTA patients. Twenty-three participants with T2D and HTA (20 women) participated in a controlled HIIT program. Fourteen participants attended 90% of more session of exercise and were considered as adherent. Adherent and non-adherent participants had similar body mass index (BMI), and blood pressure. A “1x2x10” (work: rest-time: intervals) HIIT exercise protocol was used both as a test and as training method during twelve weeks. The initial and finishing heart rate (HR) of each of the ten intervals before and after the intervention were measured. After twelve weeks of HIIT intervention, adherent participants had a significant reduction in the heart rate at the onset of exercise, and during intervals 4, 5, 8 and 10. A reduction in the final heart rate was observed during intervals 8 and 10. In the same participants the greatest magnitude of reduction, at the onset or end of exercise was approximately 10 beats/min. No significant changes in BMI, resting heart rate and blood pressure were observed. A HIIT program reduces the cardiovascular effort to a given work-load and improves cardiovascular recovery after exercise.

Heat Production During Countermeasure Exercises Planned for the International Space Station

NASA Technical Reports Server (NTRS)

Rapley, Michael G.; Lee, Stuart M. C.; Guilliams, Mark E.; Greenisen, Michael C.; Schneider, Suzanne M.

2004-01-01

This investigation's purpose was to determine the amount of heat produced when performing aerobic and resistance exercises planned as part of the exercise countermeasures prescription for the ISS. These data will be used to determine thermal control requirements of the Node 1 and other modules where exercise hardware might reside. To determine heat production during resistive exercise, 6 subjects using the iRED performed 5 resistance exercises which form the core exercises of the current ISS resistive exercise countermeasures. Each exerciser performed a warm-up set at 50% effort, then 3 sets of increasing resistance. We measured oxygen consumption and work during each exercise. Heat loss was calculated as the difference between the gross energy expenditure (minus resting metabolism) and the work performed. To determine heat production during aerobic exercise, 14 subjects performed an interval, cycle exercise protocol and 7 subjects performed a continuous, treadmill protocol. Each 30-min. exercise is similar to exercises planned for ISS. Oxygen consumption monitored continuously during the exercises was used to calculate the gross energy expenditure. For cycle exercise, work performed was calculated based on the ergometer's resistance setting and pedaling frequency. For treadmill, total work was estimated by assuming 25% work efficiency and subtracting the calculated heat production and resting metabolic rate from the gross energy expenditure. This heat production needs to be considered when determining the location of exercise hardware on ISS and designing environmental control systems. These values reflect only the human subject s produced heat; heat produced by the exercise hardware also will contribute to the heat load.

V02 'overshoot' during moderate-intensity exercise in endurance-trained athletes: the influence of exercise modality.

PubMed

Kilding, Andrew E; Jones, Andrew M

2008-02-01

The purpose of this study was to investigate the influence of exercise modality on the 'overshoot' in V(O2) that has been reported following the onset of moderate-intensity (below the gas exchange threshold, GET) exercise in endurance athletes. Seven trained endurance cyclists and seven trained endurance runners completed six square-wave transitions to a work-rate or running speed requiring 80% of mode-specific GET during both cycle and treadmill running exercise. The kinetics of V(O2) was assessed using non-linear regression and any overshoot in V(O2) was quantified as the integrated volume (IV) of O(2) consumed above the steady-state requirement. During cycling, an overshoot in V(O2) was evident in all seven cyclists (IV = 136 +/- 41 ml) and in four runners (IV = 81 +/- 94 ml). During running, an overshoot in V(O2) was evident in four runners (IV = 72 +/- 61 ml) but no cyclists. These data challenge the notion that V(O2) always rises towards a steady-state with near-exponential kinetics in this exercise intensity domain. The greater incidence of the V(O2) overshoot during cycling (11/14 subjects) compared to running (4/14 subjects) indicates that the overshoot phenomenon is related to an interaction between high levels of aerobic fitness and exercise modality. We speculate that a transient loss in muscle efficiency as a consequence of a non-constant ATP requirement following the onset of constant-work-rate exercise or an initially excessive recruitment of motor units (relative to the work-rate) might contribute to the overshoot phenomenon.

Effectiveness of exercise-heat acclimation for preventing heat illness in the workplace.

PubMed

Yamazaki, Fumio

2013-09-01

The incidence of heat-related illness in the workplace is linked to whether or not workers have acclimated to a hot environment. Heat acclimation improves endurance work performance in the heat and thermal comfort at a given work rate. These improvements are achieved by increased sweating and skin blood flow responses, better fluid balance and cardiovascular stability. As a practical means of acclimatizing the body to heat stress, daily aerobic exercise training is recommended since thermoregulatory capacity and blood volume increase with physical fitness. In workers wearing personal protective suits in hot environments, however, little psychophysiological benefit is received from short-term exercise training and/or heat acclimation because of the ineffectiveness of sweating for heat dissipation and the aggravation of thermal discomfort with the accumulation of sweat within the suit. For a manual laborer who works under uncompensable heat stress, better management of the work rate, the work environment and health is required.

A systematic review of the safety and efficacy of aerobic exercise during cytotoxic chemotherapy treatment.

PubMed

Cave, J; Paschalis, A; Huang, C Y; West, M; Copson, E; Jack, S; Grocott, M P W

2018-06-24

Aerobic exercise improves prognosis and quality of life (QoL) following completion of chemotherapy. However, the safety and efficacy of aerobic exercise during chemotherapy is less certain. A systematic review was performed of randomised trials of adult patients undergoing chemotherapy, comparing an exercise intervention with standard care. From 253 abstracts screened, 33 unique trials were appraised in accordance with PRISMA guidance, including 3257 patients. Interventions included walking, jogging or cycling, and 23 were of moderate intensity (50-80% maximum heart rate). Aerobic exercise improved, or at least maintained fitness during chemotherapy. Moderately intense exercise, up to 70-80% of maximum heart rate, was safe. Any reported adverse effects of exercise were mild and self-limiting, but reporting was inconsistent. Adherence was good (median 72%). Exercise improved QoL and physical functioning, with earlier return to work. Two out of four studies reported improved chemotherapy completion rates. Four out of six studies reported reduced chemotherapy toxicity. There was no evidence that exercise reduced myelosuppression or improved response rate or survival. Exercise during chemotherapy is safe and should be encouraged because of beneficial effects on QoL and physical functioning. More research is required to determine the impact on chemotherapy completion rates and prognosis.

Effectiveness of an upper extremity exercise device integrated with computer gaming for aerobic training in adolescents with spinal cord dysfunction.

PubMed

Widman, Lana M; McDonald, Craig M; Abresch, R Ted

2006-01-01

To determine whether a new upper extremity exercise device integrated with a video game (GameCycle) requires sufficient metabolic demand and effort to induce an aerobic training effect and to explore the feasibility of using this system as an exercise modality in an exercise intervention. Pre-post intervention. University-based research facility. SUBJECT POPULATION: A referred sample of 8 adolescent subjects with spina bifida (4 girls, 15.5 +/- 0.6 years; 4 boys, 17.5 +/- 0.9 years) was recruited to participate in the project. All subjects had some level of mobility impairment that did not allow them to participate in mainstream sports available to their nondisabled peers. Five subjects used a wheelchair full time, one used a wheelchair occasionally, but walked with forearm crutches, and 2 were fully ambulatory, but had impaired gait. Peak oxygen uptake, maximum work output, aerobic endurance, peak heart rate, rating of perceived exertion, and user satisfaction. Six of the 8 subjects were able to reach a Vo2 of at least 50% of their Vo2 reserve while using the GameCycle. Seven of the 8 subjects reached a heart rate of at least 50% of their heart rate reserve. One subject did not reach either 50% of Vo2 reserve or 50% of heart rate reserve. Seven of the 8 subjects increased their maximum work capability after training with the GameCycle at least 3 times per week for 16 weeks. The data suggest that the GameCycle seems to be adequate as an exercise device to improve oxygen uptake and maximum work capability in adolescents with lower extremity disability caused by spinal cord dysfunction. The subjects in this study reported that the video game component was enjoyable and provided a motivation to exercise.

Continuous vs. intermittent work with Canadian Forces NBC clothing.

PubMed

McLellan, T M; Jacobs, I; Bain, J B

1993-07-01

This study examined the benefits of work and rest schedules on soldiers' work tolerance (WTT) while wearing various levels of nuclear, biological and chemical (NBC) defence protective clothing in a warm environment (30 degrees C and 50% R.H.). Eight unacclimatized males were assigned to exercise at either a light (walking 1.11 m.s-1 0% grade, alternating with lifting 10 kg) or heavy metabolic rate (walking 1.33 m.s-1 7.5% grade, alternating with lifting 20 kg). Subjects were tested wearing three levels of clothing protection: combat clothing (L); combats and a semi-permeable NBC overgarment with the hood down (M); combats and NBC overgarment, gloves, boots and respirator (H). For each clothing configuration, subjects were evaluated using both a "continuous" exercise protocol and an intermittent work and rest schedule. WTT was defined as the time until rectal temperature (Tre) reached 39.3 degrees C, heart rate reached 95% maximum, dizziness or nausea precluded further exercise, or 5 h had elapsed. Assuming a resting VO2 of 4 ml.kg-1 x min-1 an average metabolic rate was calculated for all trials. A decreasing hyperbolic function described the relationship between WTT and metabolic rate for M and H. These relationships facilitate quantification of appropriate work and rest schedules if the metabolic rate of a task is known.

Active workstation allows office workers to work efficiently while sitting and exercising moderately.

PubMed

Koren, Katja; Pišot, Rado; Šimunič, Boštjan

2016-05-01

To determine the effects of a moderate-intensity active workstation on time and error during simulated office work. The aim of the study was to analyse simultaneous work and exercise for non-sedentary office workers. We monitored oxygen uptake, heart rate, sweating stains area, self-perceived effort, typing test time with typing error count and cognitive performance during 30 min of exercise with no cycling or cycling at 40 and 80 W. Compared baseline, we found increased physiological responses at 40 and 80 W, which corresponds to moderate physical activity (PA). Typing time significantly increased by 7.3% (p = 0.002) in C40W and also by 8.9% (p = 0.011) in C80W. Typing error count and cognitive performance were unchanged. Although moderate intensity exercise performed on cycling workstation during simulated office tasks increases working task execution time with, it has moderate effect size; however, it does not increase the error rate. Participants confirmed that such a working design is suitable for achieving the minimum standards for daily PA during work hours. Copyright © 2015 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Accuracy of pulse oximeters in estimating heart rate at rest and during exercise.

PubMed Central

Iyriboz, Y; Powers, S; Morrow, J; Ayers, D; Landry, G

1991-01-01

Pulse oximeters are being widely used for non-invasive, simultaneous assessment of haemoglobin oxygen saturation. They are reliable, accurate, relatively inexpensive and portable. Pulse oximeters are often used for estimating heart rate at rest and during exercise. However, at present the data available to validate their use as heart rate monitors are not sufficient. We evaluated the accuracy of two oximeters (Radiometer, ear and finger probe; Ohmeda 3700, ear probe) in monitoring heart rate during incremental exercise by comparing the pulse oximeters with simultaneous ECG readings. Data were collected on eight men (713 heart rate readings) during graded cycle ergometer and treadmill exercise to volitional fatigue. Analysis by linear regression revealed that general oximeter readings significantly correlated with those of ECG (r = 0.91, P less than 0.0001). However, comparison of heart rate at each level of work showed that oximeter readings significantly (P less than 0.05) under-estimated rates above 155 beats/min. These results indicate that the use of pulse oximeters as heart rate monitors during strenuous exercise is questionable. This inaccuracy may well originate from the instability of the probes, sweating, other artefacts during exercise, and measurement of different components in the cardiovascular cycle. PMID:1777787

Dissociating external power from intramuscular exercise intensity during intermittent bilateral knee‐extension in humans

PubMed Central

Davies, Matthew J.; Benson, Alan P.; Cannon, Daniel T.; Marwood, Simon; Kemp, Graham J.; Rossiter, Harry B.

2017-01-01

Key points Continuous high‐intensity constant‐power exercise is unsustainable, with maximal oxygen uptake (V˙O2 max ) and the limit of tolerance attained after only a few minutes.Performing the same power intermittently reduces the O2 cost of exercise and increases tolerance. The extent to which this dissociation is reflected in the intramuscular bioenergetics is unknown.We used pulmonary gas exchange and 31P magnetic resonance spectroscopy to measure whole‐body V˙O2, quadriceps phosphate metabolism and pH during continuous and intermittent exercise of different work:recovery durations.Shortening the work:recovery durations (16:32 s vs. 32:64 s vs. 64:128 s vs. continuous) at a work rate estimated to require 110% peak aerobic power reduced V˙O2, muscle phosphocreatine breakdown and muscle acidification, eliminated the glycolytic‐associated contribution to ATP synthesis, and increased exercise tolerance.Exercise intensity (i.e. magnitude of intramuscular metabolic perturbations) can be dissociated from the external power using intermittent exercise with short work:recovery durations. Abstract Compared with work‐matched high‐intensity continuous exercise, intermittent exercise dissociates pulmonary oxygen uptake (V˙O2) from the accumulated work. The extent to which this reflects differences in O2 storage fluctuations and/or contributions from oxidative and substrate‐level bioenergetics is unknown. Using pulmonary gas‐exchange and intramuscular 31P magnetic resonance spectroscopy, we tested the hypotheses that, at the same power: ATP synthesis rates are similar, whereas peak V˙O2 amplitude is lower in intermittent vs. continuous exercise. Thus, we expected that: intermittent exercise relies less upon anaerobic glycolysis for ATP provision than continuous exercise; shorter intervals would require relatively greater fluctuations in intramuscular bioenergetics than in V˙O2 compared to longer intervals. Six men performed bilateral knee‐extensor exercise (estimated to require 110% peak aerobic power) continuously and with three different intermittent work:recovery durations (16:32, 32:64 and 64:128 s). Target work duration (576 s) was achieved in all intermittent protocols; greater than continuous (252 ± 174 s; P < 0.05). Mean ATP turnover rate was not different between protocols (∼43 mm min−1 on average). However, the intramuscular phosphocreatine (PCr) component of ATP generation was greatest (∼30 mm min−1), and oxidative (∼10 mm min−1) and anaerobic glycolytic (∼1 mm min−1) components were lowest for 16:32 and 32:64 s intermittent protocols, compared to 64:128 s (18 ± 6, 21 ± 10 and 10 ± 4 mm min−1, respectively) and continuous protocols (8 ± 6, 20 ± 9 and 16 ± 14 mm min−1, respectively). As intermittent work duration increased towards continuous exercise, ATP production relied proportionally more upon anaerobic glycolysis and oxidative phosphorylation, and less upon PCr breakdown. However, performing the same high‐intensity power intermittently vs. continuously reduced the amplitude of fluctuations in V˙O2 and intramuscular metabolism, dissociating exercise intensity from the power output and work done. PMID:28776675

Dietary Nitrate Supplementation Improves Exercise Performance and Decreases Blood Pressure in COPD Patients

PubMed Central

Berry, Michael J.; Justus, Nicholas W.; Hauser, Jordan I.; Case, Ashlee H.; Helms, Christine C.; Basu, Swati; Rogers, Zachary; Lewis, Marc T.; Miller, Gary D.

2014-01-01

Dietary nitrate (NO3−) supplementation via beetroot juice has been shown to increase the exercise capacity of younger and older adults. The purpose of this study was to investigate the effects of acute NO3− ingestion on the submaximal constant work rate exercise capacity of COPD patients. Fifteen patients were assigned in a randomized, single-blind, crossover design to receive one of two treatments (beetroot juice then placebo or placebo then beetroot juice). Submaximal constant work rate exercise time at 75% of the patient’s maximal work capacity was the primary outcome. Secondary outcomes included plasma NO3− and nitrite (NO2−) levels, blood pressure, heart rate, oxygen consumption (VO2), dynamic hyperinflation, dyspnea and leg discomfort. Relative to placebo, beetroot ingestion increased plasma NO3− by 938% and NO2− by 379%. Median (+ interquartile range) exercise time was significantly longer (p = 0.031) following the ingestion of beetroot versus placebo (375.0 + 257.0 vs. 346.2 + 148.0 sec., respectively). Compared to placebo, beetroot ingestion significantly reduced iso-time (p = 0.001) and end exercise (p = 0.008) diastolic blood pressures by 6.4 and 5.6 mmHg, respectively. Resting systolic blood pressure was significantly reduced (p = 0.019) by 8.2 mmHg for the beetroot versus the placebo trial. No other variables were significantly different between the beetroot and placebo trials. These results indicate that acute dietary NO3− supplementation can elevate plasma NO3− and NO2− concentrations, improve exercise performance, and reduce blood pressure in COPD patients. PMID:25445634

Dietary nitrate supplementation improves exercise performance and decreases blood pressure in COPD patients.

PubMed

Berry, Michael J; Justus, Nicholas W; Hauser, Jordan I; Case, Ashlee H; Helms, Christine C; Basu, Swati; Rogers, Zachary; Lewis, Marc T; Miller, Gary D

2015-08-01

Dietary nitrate (NO3(-)) supplementation via beetroot juice has been shown to increase the exercise capacity of younger and older adults. The purpose of this study was to investigate the effects of acute NO3(-) ingestion on the submaximal constant work rate exercise capacity of COPD patients. Fifteen patients were assigned in a randomized, single-blind, crossover design to receive one of two treatments (beetroot juice then placebo or placebo then beetroot juice). Submaximal constant work rate exercise time at 75% of the patient's maximal work capacity was the primary outcome. Secondary outcomes included plasma NO3(-) and nitrite (NO2(-)) levels, blood pressure, heart rate, oxygen consumption (VO2), dynamic hyperinflation, dyspnea and leg discomfort. Relative to placebo, beetroot ingestion increased plasma NO3(-) by 938% and NO2(-) by 379%. Median (+interquartile range) exercise time was significantly longer (p = 0.031) following the ingestion of beetroot versus placebo (375.0 + 257.0 vs. 346.2 + 148.0 s, respectively). Compared with placebo, beetroot ingestion significantly reduced iso-time (p = 0.001) and end exercise (p = 0.008) diastolic blood pressures by 6.4 and 5.6 mmHg, respectively. Resting systolic blood pressure was significantly reduced (p = 0.019) by 8.2 mmHg for the beetroot versus the placebo trial. No other variables were significantly different between the beetroot and placebo trials. These results indicate that acute dietary NO3(-) supplementation can elevate plasma NO3(-) and NO2(-) concentrations, improve exercise performance, and reduce blood pressure in COPD patients. Copyright © 2014 Elsevier Inc. All rights reserved.

Inhaled fentanyl citrate improves exercise endurance during high-intensity constant work rate cycle exercise in chronic obstructive pulmonary disease.

PubMed

Jensen, Dennis; Alsuhail, Abdullah; Viola, Raymond; Dudgeon, Deborah J; Webb, Katherine A; O'Donnell, Denis E

2012-04-01

Activity limitation and dyspnea are the dominant symptoms of chronic obstructive pulmonary disease (COPD). Traditionally, efforts to alleviate these symptoms have focused on improving ventilatory mechanics, reducing ventilatory demand, or both of these in combination. Nevertheless, many patients with COPD remain incapacitated by dyspnea and exercise intolerance despite optimal therapy. To determine the effect of single-dose inhalation of nebulized fentanyl citrate (a μ-opioid agonist drug) on exercise tolerance and dyspnea in COPD. In a randomized, double-blind, placebo-controlled, crossover study, 12 stable patients with COPD (mean ± standard error of the mean post-β(2)-agonist forced expiratory volume in one second [FEV(1)] and FEV(1) to forced vital capacity ratio of 69% ± 4% predicted and 49% ± 3%, respectively) received either nebulized fentanyl citrate (50 mcg) or placebo on two separate days. After each treatment, patients performed pulmonary function tests and a symptom-limited constant work rate cycle exercise test at 75% of their maximum incremental work rate. There were no significant postdose differences in spirometric parameters or plethysmographic lung volumes. Neither the intensity nor the unpleasantness of perceived dyspnea was, on average, significantly different at isotime (5.0 ± 0.6 minutes) or at peak exercise after treatment with fentanyl citrate vs. placebo. Compared with placebo, fentanyl citrate was associated with 1) increased exercise endurance time by 1.30 ± 0.43 minutes or 25% ± 8% (P=0.01); 2) small but consistent increases in dynamic inspiratory capacity by ∼0.10 L at isotime and at peak exercise (both P≤0.03); and 3) no concomitant change in ventilatory demand, breathing pattern, pulmonary gas exchange, and/or cardiometabolic function during exercise. The mean rate of increase in dyspnea intensity (1.2 ± 0.3 vs. 2.9 ± 0.8 Borg units/minute, P=0.03) and unpleasantness ratings (0.5 ± 0.2 vs. 2.9 ± 1.3 Borg units/minute, P=0.06) between isotime and peak exercise was less after treatment with fentanyl citrate vs. placebo. Single-dose inhalation of fentanyl citrate was associated with significant and potentially clinically important improvements in exercise tolerance in COPD. These improvements were accompanied by a delay in the onset of intolerable dyspnea during exercise near the limits of tolerance. Copyright © 2012 U.S. Cancer Pain Relief Committee. Published by Elsevier Inc. All rights reserved.

How to avoid overheating during exercise

MedlinePlus

... is always working to maintain a safe temperature. Sweating helps your body cool down. When you exercise ... your muscles. This increases your heart rate. You sweat a lot, losing fluids in your body. If ...

Feasibility of cardiopulmonary exercise testing and training using a robotics-assisted tilt table in dependent-ambulatory stroke patients.

PubMed

Saengsuwan, Jittima; Huber, Celine; Schreiber, Jonathan; Schuster-Amft, Corina; Nef, Tobias; Hunt, Kenneth J

2015-09-26

We evaluated the feasibility of an augmented robotics-assisted tilt table (RATT) for incremental cardiopulmonary exercise testing (CPET) and exercise training in dependent-ambulatory stroke patients. Stroke patients (Functional Ambulation Category ≤ 3) underwent familiarization, an incremental exercise test (IET) and a constant load test (CLT) on separate days. A RATT equipped with force sensors in the thigh cuffs, a work rate estimation algorithm and real-time visual feedback to guide the exercise work rate was used. Feasibility assessment considered technical feasibility, patient tolerability, and cardiopulmonary responsiveness. Eight patients (4 female) aged 58.3 ± 9.2 years (mean ± SD) were recruited and all completed the study. For IETs, peak oxygen uptake (V'O2peak), peak heart rate (HRpeak) and peak work rate (WRpeak) were 11.9 ± 4.0 ml/kg/min (45 % of predicted V'O2max), 117 ± 32 beats/min (72 % of predicted HRmax) and 22.5 ± 13.0 W, respectively. Peak ratings of perceived exertion (RPE) were on the range "hard" to "very hard". All 8 patients reached their limit of functional capacity in terms of either their cardiopulmonary or neuromuscular performance. A ventilatory threshold (VT) was identified in 7 patients and a respiratory compensation point (RCP) in 6 patients: mean V'O2 at VT and RCP was 8.9 and 10.7 ml/kg/min, respectively, which represent 75 % (VT) and 85 % (RCP) of mean V'O2peak. Incremental CPET provided sufficient information to satisfy the responsiveness criteria and identification of key outcomes in all 8 patients. For CLTs, mean steady-state V'O2 was 6.9 ml/kg/min (49 % of V'O2 reserve), mean HR was 90 beats/min (56 % of HRmax), RPEs were > 2, and all patients maintained the active work rate for 10 min: these values meet recommended intensity levels for bouts of training. The augmented RATT is deemed feasible for incremental cardiopulmonary exercise testing and exercise training in dependent-ambulatory stroke patients: the approach was found to be technically implementable, acceptable to the patients, and it showed substantial cardiopulmonary responsiveness. This work has clinical implications for patients with severe disability who otherwise are not able to be tested.

Effect of different musical tempo on post-exercise recovery in young adults.

PubMed

Savitha, D; Mallikarjuna, Reddy N; Rao, Chythra

2010-01-01

The role of music in increasing the exercise performance is well recognised. There is very little information about effect of music on time taken for post exercise recovery. We examined the effect of music and different musical tempo on post exercise recovery time, following treadmill work. 30 volunteers (15 male, 15 female) subjected to isotonic exercise (submaximal treadmill work) on three consecutive days. They were allowed to rest in silence on the first day, rest by hearing slow music on second day and rest with fast music on third day. Parameters such as Pulse rate, blood pressure, rating of perceived exertion (RPE) were measured at predetermined intervals. Repeated measures ANOVA test showed that with slow music, recovery time of systolic blood pressure (SBP) (7.9 +/- 2.5), diastolic blood pressure (DBP) (5.5 +/- 3.4) pulse rate recovery (PR) (8.0 +/- 2.3) and recovery from exertion (RPE) (7.7 +/- 2.5) were significantly faster when compared to both no music and fast music. The individual music preference made no significant difference in the relaxation time. The study concluded that music hastens post exercise recovery and slow music has greater relaxation effect than fast or no music, recovery time being independent of the gender and individual music preference.

The Influence of Exercise Intensity on Postexercise Baroreflex Sensitivity

ERIC Educational Resources Information Center

Reynolds, Linda J.; De Ste Croix, Mark B. A.; James, David V. B.

2017-01-01

Purpose: The purpose of this study was to investigate the influence of exercise intensity on postexercise supine and tilt baroreflex sensitivity (BRS). Method: Nine healthy, active men performed 2 conditions of interval cycling of 40% maximal work rate (WR[subscript max]) and 75% WR[subscript max] of matched work done and a control condition of no…

Intensity and duration of intermittent exercise and recovery during a soccer match.

PubMed

Orendurff, Michael S; Walker, Jason D; Jovanovic, Mladen; Tulchin, Kirsten L; Levy, Morris; Hoffmann, David K

2010-10-01

Soccer is a sport consisting of high-intensity intermittent exercise, with players making forays across their anaerobic threshold for tactical advantage followed by periods of recovery. The intensity and duration of these work and recovery bouts were defined during a men's soccer match using StepWatch Activity Monitors recording step rate for each 3-second period. The data were coded by custom software to separate work bouts (step rate ≥ 4) from recovery bouts (step rate < 4), and a square wave of the pattern of bouts was plotted for 5 players: center forward, central midfielder, wing midfielder, central defender, and wing defender. Four values were calculated for each work and recovery bout identified: duration, and mean, maximum, and minimum step rate (intensity). This novel technique provided detailed graphical information on the duration and exercise intensity of each position throughout the match. The center midfielder was able to sustain work and recovery bout characteristics throughout the match and appeared to recover at higher intensity levels than other players. The forward showed the consequence of accumulated fatigue late in the match and was unable to sustain the duration of high-intensity work bouts observed earlier in the match. The central defender attenuated the intensity of his work and recovery bouts late in the match staying closer to a more moderate work rate with fewer high- or low-intensity bouts. Having objective data qualifying players' work and recovery bout characteristics might prove valuable for tactical decision making, substitution timing, and for planning future training sessions.

Return to work of cancer patients after a multidisciplinary intervention including occupational counselling and physical exercise in cancer patients: a prospective study in the Netherlands.

PubMed

Leensen, Monique C J; Groeneveld, Iris F; Heide, Iris van der; Rejda, Tomas; van Veldhoven, Peter L J; Berkel, Sietske van; Snoek, Aernout; Harten, Wim van; Frings-Dresen, Monique H W; de Boer, Angela G E M

2017-06-15

To support return to work (RTW) among cancer patients, a multidisciplinary rehabilitation programme was developed which combined occupational counselling with a supervised physical exercise programme during chemotherapy. The aim was to investigate RTW rates of cancer patients and to evaluate changes in work-related quality of life and physical outcomes. Longitudinal prospective intervention study using a one-group design. Two hospitals in the Netherlands. Of the eligible patients, 56% participated; 93 patients with a primary diagnosis of cancer receiving chemotherapy and on sick leave were included. Patients completed questionnaires on RTW, the importance of work, work ability (WAI), RTW self-efficacy, fatigue (MFI), and quality of life (EORTC QLQ C-30) at baseline and 6, 12 and 18 months follow-up. Before and after the exercise programme 1-repetition maximum (1RM) muscle strength and cardiorespiratory fitness (VO 2 peak) were assessed. Six months after the start of a multidisciplinary rehabilitation programme that combined occupational counselling with a supervised physical exercise programme, 59% of the cancer patients returned to work, 86% at 12 months and 83% at 18 months. In addition, significant improvements (p<0.05) in the importance of work, work ability, RTW self-efficacy, and quality of life were observed, whereas fatigue levels were significantly reduced. After completing the exercise programme, 1RM muscle strength was significantly increased but there was no improvement in VO 2 peak level. RTW rates of cancer patients were high after completion of the multidisciplinary rehabilitation programme. A multidisciplinary rehabilitation programme which combines occupational counselling with a supervised physical exercise programme is likely to result in RTW, reduced fatigue and increased importance of work, work ability, and quality of life. © 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.

Return to work of cancer patients after a multidisciplinary intervention including occupational counselling and physical exercise in cancer patients: a prospective study in the Netherlands

PubMed Central

Leensen, Monique C J; Groeneveld, Iris F; van der Heide, Iris; Rejda, Tomas; van Veldhoven, Peter L J; van Berkel, Sietske; Snoek, Aernout; van Harten, Wim; Frings-Dresen, Monique H W; de Boer, Angela G E M

2017-01-01

Objectives To support return to work (RTW) among cancer patients, a multidisciplinary rehabilitation programme was developed which combined occupational counselling with a supervised physical exercise programme during chemotherapy. The aim was to investigate RTW rates of cancer patients and to evaluate changes in work-related quality of life and physical outcomes. Design Longitudinal prospective intervention study using a one-group design. Setting Two hospitals in the Netherlands. Participants Of the eligible patients, 56% participated; 93 patients with a primary diagnosis of cancer receiving chemotherapy and on sick leave were included. Patients completed questionnaires on RTW, the importance of work, work ability (WAI), RTW self-efficacy, fatigue (MFI), and quality of life (EORTC QLQ C-30) at baseline and 6, 12 and 18 months follow-up. Before and after the exercise programme 1-repetition maximum (1RM) muscle strength and cardiorespiratory fitness (VO2 peak) were assessed. Results Six months after the start of a multidisciplinary rehabilitation programme that combined occupational counselling with a supervised physical exercise programme, 59% of the cancer patients returned to work, 86% at 12 months and 83% at 18 months. In addition, significant improvements (p<0.05) in the importance of work, work ability, RTW self-efficacy, and quality of life were observed, whereas fatigue levels were significantly reduced. After completing the exercise programme, 1RM muscle strength was significantly increased but there was no improvement in VO2 peak level. Conclusions RTW rates of cancer patients were high after completion of the multidisciplinary rehabilitation programme. A multidisciplinary rehabilitation programme which combines occupational counselling with a supervised physical exercise programme is likely to result in RTW, reduced fatigue and increased importance of work, work ability, and quality of life. PMID:28619770

Effects of acute hypoxia on the determination of anaerobic threshold using the heart rate-work rate relationships during incremental exercise tests.

PubMed

Ozcelik, O; Kelestimur, H

2004-01-01

Anaerobic threshold which describes the onset of systematic increase in blood lactate concentration is a widely used concept in clinical and sports medicine. A deflection point between heart rate-work rate has been introduced to determine the anaerobic threshold non-invasively. However, some researchers have consistently reported a heart rate deflection at higher work rates, while others have not. The present study was designed to investigate whether the heart rate deflection point accurately predicts the anaerobic threshold under the condition of acute hypoxia. Eight untrained males performed two incremental exercise tests using an electromagnetically braked cycle ergometer: one breathing room air and one breathing 12 % O2. The anaerobic threshold was estimated using the V-slope method and determined from the increase in blood lactate and the decrease in standard bicarbonate concentration. This threshold was also estimated by in the heart rate-work rate relationship. Not all subjects exhibited a heart rate deflection. Only two subjects in the control and four subjects in the hypoxia groups showed a heart rate deflection. Additionally, the heart rate deflection point overestimated the anaerobic threshold. In conclusion, the heart rate deflection point was not an accurate predictor of anaerobic threshold and acute hypoxia did not systematically affect the heart rate-work rate relationships.

Do nonexercisers also share the positive exerciser stereotype?: An elicitation and comparison of beliefs about exercisers.

PubMed

Rodgers, Wendy M; Hall, Craig R; Wilson, Philip M; Berry, Tanya R

2009-02-01

The purpose of this research was to examine whether exercisers and nonexercisers are rated similarly on a variety of characteristics by a sample of randomly selected regular exercisers, nonexercisers who intend to exercise, and nonexercisers with no intention to exercise. Previous research by Martin Ginis et al. (2003) has demonstrated an exerciser stereotype that advantages exercisers. It is unknown, however, the extent to which an exerciser stereotype is shared by nonexercisers, particularly nonintenders. Following an item-generation procedure, a sample of 470 (n=218 men; n=252 women) people selected using random digit dialing responded to a questionnaire assessing the extent to which they agreed that exercisers and nonexercisers possessed 24 characteristics, such as "happy," "fit," "fat," and "lazy." The results strongly support a positive exerciser bias, with exercisers rated more favorably on 22 of the 24 items. The degree of bias was equivalent in all groups of respondents. Examination of the demographic characteristics revealed no differences among the three groups on age, work status, or child-care responsibilities, suggesting that there is a pervasive positive exerciser bias.

Effectiveness of an Upper Extremity Exercise Device Integrated With Computer Gaming for Aerobic Training in Adolescents With Spinal Cord Dysfunction

PubMed Central

Widman, Lana M; McDonald, Craig M; Abresch, R. Ted

2006-01-01

Background/Objective: To determine whether a new upper extremity exercise device integrated with a video game (GameCycle) requires sufficient metabolic demand and effort to induce an aerobic training effect and to explore the feasibility of using this system as an exercise modality in an exercise intervention. Design: Pre-post intervention. Setting: University-based research facility. Subject Population: A referred sample of 8 adolescent subjects with spina bifida (4 girls, 15.5 ± 0.6 years; 4 boys, 17.5 ± 0.9 years) was recruited to participate in the project. All subjects had some level of mobility impairment that did not allow them to participate in mainstream sports available to their nondisabled peers. Five subjects used a wheelchair full time, one used a wheelchair occasionally, but walked with forearm crutches, and 2 were fully ambulatory, but had impaired gait. Main Outcome Measures: Peak oxygen uptake, maximum work output, aerobic endurance, peak heart rate, rating of perceived exertion, and user satisfaction. Results: Six of the 8 subjects were able to reach a Vo2 of at least 50% of their Vo2 reserve while using the GameCycle. Seven of the 8 subjects reached a heart rate of at least 50% of their heart rate reserve. One subject did not reach either 50% of Vo2 reserve or 50% of heart rate reserve. Seven of the 8 subjects increased their maximum work capability after training with the GameCycle at least 3 times per week for 16 weeks. Conclusions: The data suggest that the GameCycle seems to be adequate as an exercise device to improve oxygen uptake and maximum work capability in adolescents with lower extremity disability caused by spinal cord dysfunction. The subjects in this study reported that the video game component was enjoyable and provided a motivation to exercise. PMID:17044386

Increased respiratory neural drive and work of breathing in exercise-induced laryngeal obstruction.

PubMed

Walsted, Emil S; Faisal, Azmy; Jolley, Caroline J; Swanton, Laura L; Pavitt, Matthew J; Luo, Yuan-Ming; Backer, Vibeke; Polkey, Michael I; Hull, James H

2018-02-01

Exercise-induced laryngeal obstruction (EILO), a phenomenon in which the larynx closes inappropriately during physical activity, is a prevalent cause of exertional dyspnea in young individuals. The physiological ventilatory impact of EILO and its relationship to dyspnea are poorly understood. The objective of this study was to evaluate exercise-related changes in laryngeal aperture on ventilation, pulmonary mechanics, and respiratory neural drive. We prospectively evaluated 12 subjects (6 with EILO and 6 healthy age- and gender-matched controls). Subjects underwent baseline spirometry and a symptom-limited incremental exercise test with simultaneous and synchronized recording of endoscopic video and gastric, esophageal, and transdiaphragmatic pressures, diaphragm electromyography, and respiratory airflow. The EILO and control groups had similar peak work rates and minute ventilation (V̇e) (work rate: 227 ± 35 vs. 237 ± 35 W; V̇e: 103 ± 20 vs. 98 ± 23 l/min; P > 0.05). At submaximal work rates (140-240 W), subjects with EILO demonstrated increased work of breathing ( P < 0.05) and respiratory neural drive ( P < 0.05), developing in close temporal association with onset of endoscopic evidence of laryngeal closure ( P < 0.05). Unexpectedly, a ventilatory increase ( P < 0.05), driven by augmented tidal volume ( P < 0.05), was seen in subjects with EILO before the onset of laryngeal closure; there were however no differences in dyspnea intensity between groups. Using simultaneous measurements of respiratory mechanics and diaphragm electromyography with endoscopic video, we demonstrate, for the first time, increased work of breathing and respiratory neural drive in association with the development of EILO. Future detailed investigations are now needed to understand the role of upper airway closure in causing exertional dyspnea and exercise limitation. NEW & NOTEWORTHY Exercise-induced laryngeal obstruction is a prevalent cause of exertional dyspnea in young individuals; yet, how laryngeal closure affects breathing is unknown. In this study we synchronized endoscopic video with respiratory physiological measurements, thus providing the first detailed commensurate assessment of respiratory mechanics and neural drive in relation to laryngeal closure. Laryngeal closure was associated with increased work of breathing and respiratory neural drive preceded by an augmented tidal volume and a rise in minute ventilation.

Employee self-rated productivity and objective organizational production levels: effects of worksite health interventions involving reduced work hours and physical exercise.

PubMed

von Thiele Schwarz, Ulrica; Hasson, Henna

2011-08-01

To investigate how worksite health interventions involving a 2.5-hour reduction of weekly working hours with (PE) or without (RWH) mandatory physical exercise affects productivity. Six workplaces in dental health care were matched and randomized to three conditions (PE, RWH and referents). Employees' (N = 177) self-rated productivity and the workplaces' production levels (number of patients) were examined longitudinally. Number of treated patients increased in all conditions during the intervention year. While RWH showed the largest increase in this measure, PE showed significant increases in self-rated productivity, that is, increased quantity of work and work-ability and decreased sickness absence. A reduction in work hours may be used for health promotion activities with sustained or improved production levels, suggesting an increased productivity since the same, or higher, production level can be achieved with lesser resources.

Recovery from exercise at varying work loads - Time course of responses of heart rate and systolic intervals

NASA Technical Reports Server (NTRS)

Nandi, P. S.; Spodick, D. H.

1977-01-01

The time course of the recovery period was characterized by noninvasive measurements after 4 minute bicycle exercise at 3 separate work loads in volunteers with normal peak responses. Most responses started immediately to return toward resting control values. Left ventricular ejection time and stroke volume change are discussed. Changes in pre-ejection period were determined by changes in isovolume contraction time, and factors affecting the degree and rate of return are considered. The rates of change in the ejection time index and in the ratio pre-ejection period/left ventricular ejection time were virtually independent of load throughout most of recovery.

Oscillation in O2 uptake in impulse exercise.

PubMed

Yano, T; Afroundeh, R; Yamanaka, R; Arimitsu, T; Lian, C S; Shirakawa, K; Yunoki, T

2014-06-01

The purpose of the present study was to examine 1) whether O(2) uptake (VO(2)) oscillates during light exercise and 2) whether the oscillation is enhanced after impulse exercise. After resting for 1 min on a bicycle seat, subjects performed 5-min pre-exercise with 25 watts work load, 10-s impulse exercise with 200 watts work load and 15-min post exercise with 25 watts work load at 80 rpm. VO(2) during pre-exercise significantly increased during impulse exercise and suddenly decreased and re-increased until 23 s after impulse exercise. In the cross correlation between heart rate (HR) and VO(2) after impulse exercise, VO(2) strongly correlated to HR with a time delay of -4 s. Peak of power spectral density (PSD) in HR appeared at 0.0039 Hz and peak of PSD in VO(2) appeared at 0.019 Hz. The peak of the cross power spectrum between VO(2) and HR appeared at 0.0078 Hz. The results suggested that there is an oscillation in O(2) uptake during light exercise that is associated with the oscillation in O(2) consumption in active muscle. The oscillation is enhanced not only by change in O(2) consumption but also by O(2) content transported from active muscle to the lungs.

Feedback-controlled robotics-assisted treadmill exercise to assess and influence aerobic capacity early after stroke: a proof-of-concept study.

PubMed

Stoller, Oliver; Schindelholz, Matthias; Bichsel, Lukas; Schuster, Corina; de Bie, Rob A; de Bruin, Eling D; Hunt, Kenneth J

2014-07-01

The majority of post-stroke individuals suffer from low exercise capacity as a secondary reaction to immobility. The aim of this study was to prove the concept of feedback-controlled robotics-assisted treadmill exercise (RATE) to assess aerobic capacity and guide cardiovascular exercise in severely impaired individuals early after stroke. Subjects underwent constant load and incremental exercise testing using a human-in-the-loop feedback system within a robotics-assisted exoskeleton (Lokomat, Hocoma AG, CH). Inclusion criteria were: stroke onset ≤8 weeks, stable medical condition, non-ambulatory status, moderate motor control of the lower limbs and appropriate cognitive function. Outcome measures included oxygen uptake kinetics, peak oxygen uptake (VO2peak), gas exchange threshold (GET), peak heart rate (HRpeak), peak work rate (Ppeak) and accuracy of reaching target work rate (P-RMSE). Three subjects (18-42 d post-stroke) were included. Oxygen uptake kinetics during constant load ranged from 42.0 to 60.2 s. Incremental exercise testing showed: VO2peak range 19.7-28.8 ml/min/kg, GET range 11.6-12.7 ml/min/kg, and HRpeak range 115-161 bpm. Ppeak range was 55.2-110.9 W and P-RMSE range was 3.8-7.5 W. The concept of feedback-controlled RATE for assessment of aerobic capacity and guidance of cardiovascular exercise is feasible. Further research is warranted to validate the method on a larger scale. Aerobic capacity is seriously reduced in post-stroke individuals as a secondary reaction to immobility. Robotics-assisted walking devices may have substantial clinical relevance regarding assessment and improvement of aerobic capacity early after stroke. Feedback-controlled robotics-assisted treadmill exercise represents a new concept for cardiovascular assessment and intervention protocols for severely impaired individuals.

Arm mechanical efficiency and arm exercise capacity are relatively preserved in chronic obstructive pulmonary disease.

PubMed

Franssen, Frits M E; Wouters, Emiel F M; Baarends, Erica M; Akkermans, Marco A; Schols, Annemie M W J

2002-10-01

Previous studies indicate that energy expenditure related to physical activity is enhanced and that mechanical efficiency of leg exercise is reduced in patients with chronic obstructive pulmonary disease (COPD). However, it is yet unclear whether an inefficient energy expenditure is also present during other activities in COPD. This study was carried out to examine arm efficiency and peak arm exercise performance relative to leg exercise in 33 (23 male) patients with COPD ((mean +/- SEM) age: 61 +/- 2 yr; FEV : 40 +/- 2% of predicted) and 20 sex- and age-matched healthy controls. Body composition, pulmonary function, resting energy expenditure (REE), and peak leg and arm exercise performance were determined. To calculate mechanical efficiency, subjects performed submaximal leg and arm ergometry at 50% of achieved peak loads. During exercise testing, metabolic and ventilatory parameters were measured. In contrast to a reduced leg mechanical efficiency in patients compared with controls (15.6 +/- 0.6% and 22.5 +/- 0.6%, respectively; < 0.001), arm mechanical efficiency was comparable in both groups (COPD: 18.3 +/- 0.9%, controls: 21.0 +/- 1.2%; NS). Arm efficiency was not related to leg efficiency, pulmonary function, work of breathing, or REE. Also, arm exercise capacity was relatively preserved in patients with COPD (ratio arm peak work rate/leg peak work rate in patients: 89% vs 53% in controls; < 0.001). Mechanical efficiency and exercise capacity of the upper and lower limbs are not homogeneously affected in COPD, with a relative preservation of the upper limbs. This may have implications for screening of exercise tolerance and prescription of training interventions in patients with COPD. Future studies need to elucidate the mechanism behind this observation.

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

PubMed

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

2014-06-01

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

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

PubMed

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

2015-01-01

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

Dynamics of chest wall volume regulation during constant work rate exercise in patients with chronic obstructive pulmonary disease

PubMed Central

Takara, L.S.; Cunha, T.M.; Barbosa, P.; Rodrigues, M.K.; Oliveira, M.F.; Nery, L.E.; Neder, J.A.

2012-01-01

This study evaluated the dynamic behavior of total and compartmental chest wall volumes [(VCW) = rib cage (VRC) + abdomen (VAB)] as measured breath-by-breath by optoelectronic plethysmography during constant-load exercise in patients with stable chronic obstructive pulmonary disease. Thirty males (GOLD stages II-III) underwent a cardiopulmonary exercise test to the limit of tolerance (Tlim) at 75% of peak work rate on an electronically braked cycle ergometer. Exercise-induced dynamic hyperinflation was considered to be present when end-expiratory (EE) VCW increased in relation to resting values. There was a noticeable heterogeneity in the patterns of VCW regulation as EEVCW increased non-linearly in 17/30 “hyperinflators” and decreased in 13/30 “non-hyperinflators” (P < 0.05). EEVAB decreased slightly in 8 of the “hyperinflators”, thereby reducing and slowing the rate of increase in end-inspiratory (EI) VCW (P < 0.05). In contrast, decreases in EEVCW in the “non-hyperinflators” were due to the combination of stable EEVRC with marked reductions in EEVAB. These patients showed lower EIVCW and end-exercise dyspnea scores but longer Tlim than their counterparts (P < 0.05). Dyspnea increased and Tlim decreased non-linearly with a faster rate of increase in EIVCW regardless of the presence or absence of dynamic hyperinflation (P < 0.001). However, no significant between-group differences were observed in metabolic, pulmonary gas exchange and cardiovascular responses to exercise. Chest wall volumes are continuously regulated during exercise in order to postpone (or even avoid) their migration to higher operating volumes in patients with COPD, a dynamic process that is strongly dependent on the behavior of the abdominal compartment. PMID:23250012

Cardiopulmonary exercise testing early after stroke using feedback-controlled robotics-assisted treadmill exercise: test-retest reliability and repeatability.

PubMed

Stoller, Oliver; de Bruin, Eling D; Schindelholz, Matthias; Schuster-Amft, Corina; de Bie, Rob A; Hunt, Kenneth J

2014-10-11

Exercise capacity is seriously reduced after stroke. While cardiopulmonary assessment and intervention strategies have been validated for the mildly and moderately impaired populations post-stroke, there is a lack of effective concepts for stroke survivors suffering from severe motor limitations. This study investigated the test-retest reliability and repeatability of cardiopulmonary exercise testing (CPET) using feedback-controlled robotics-assisted treadmill exercise (FC-RATE) in severely motor impaired individuals early after stroke. 20 subjects (age 44-84 years, <6 month post-stroke) with severe motor limitations (Functional Ambulatory Classification 0-2) were selected for consecutive constant load testing (CLT) and incremental exercise testing (IET) within a powered exoskeleton, synchronised with a treadmill and a body weight support system. A manual human-in-the-loop feedback system was used to guide individual work rate levels. Outcome variables focussed on standard cardiopulmonary performance parameters. Relative and absolute test-retest reliability were assessed by intraclass correlation coefficients (ICC), standard error of the measurement (SEM), and minimal detectable change (MDC). Mean difference, limits of agreement, and coefficient of variation (CoV) were estimated to assess repeatability. Peak performance parameters during IET yielded good to excellent relative reliability: absolute peak oxygen uptake (ICC =0.82), relative peak oxygen uptake (ICC =0.72), peak work rate (ICC =0.91), peak heart rate (ICC =0.80), absolute gas exchange threshold (ICC =0.91), relative gas exchange threshold (ICC =0.88), oxygen cost of work (ICC =0.87), oxygen pulse at peak oxygen uptake (ICC =0.92), ventilation rate versus carbon dioxide output slope (ICC =0.78). For these variables, SEM was 4-13%, MDC 12-36%, and CoV 0.10-0.36. CLT revealed high mean differences and insufficient test-retest reliability for all variables studied. This study presents first evidence on reliability and repeatability for CPET in severely motor impaired individuals early after stroke using a feedback-controlled robotics-assisted treadmill. The results demonstrate good to excellent test-retest reliability and appropriate repeatability for the most important peak cardiopulmonary performance parameters. These findings have important implications for the design and implementation of cardiovascular exercise interventions in severely impaired populations. Future research needs to develop advanced control strategies to enable the true limit of functional exercise capacity to be reached and to further assess test-retest reliability and repeatability in larger samples.

Effect of Aerobic Exercise Training on Ventilatory Efficiency and Respiratory Drive in Obese Subjects.

PubMed

Chlif, Mehdi; Chaouachi, Anis; Ahmaidi, Said

2017-07-01

Obese patients show a decline in exercise capacity and diverse degrees of dyspnea in association with mechanical abnormalities, increased ventilatory requirements secondary to the increased metabolic load, and a greater work of breathing. Consequently, obese patients may be particularly predisposed to the development of respiratory muscle fatigue during exercise. The aim of this study was to assess inspiratory muscle performance during incremental exercise in 19 obese male subjects (body mass index 41 ± 6 kg/m 2 ) after aerobic exercise training using the noninvasive, inspiratory muscle tension-time index (T T0.1 ). Measurements performed included anthropometric parameters, lung function assessed by spirometry, rate of perceived breathlessness with the modified Borg dyspnea scale (0-10), breathing pattern, maximal exercise capacity, and inspiratory muscle performance with a breath-by-breath automated exercise metabolic system during an incremental exercise test. T T0.1 was calculated using the equation, T T0.1 = P 0.1 /P Imax × T I /T tot (where P 0.1 represents mouth occlusion pressure, P Imax is maximal inspiratory pressure, and T I /T tot is the duty cycle). At rest, there was no statistically significant difference for spirometric parameters and cardiorespiratory parameters between pre- and post-training. At maximal exercise, the minute ventilation, the rate of exchange ratio, the rate of perceived breathlessness, and the respiratory muscle performance parameters were not significantly different pre- and post-training; in contrast, tidal volume ( P = .037, effect size = 1.51), breathing frequency ( P = .049, effect size = 0.97), power output ( P = .048, effect size = 0.79), peak oxygen uptake ( P = .02, effect size = 0.92) were significantly higher after training. At comparable work load, training induces lower minute ventilation, mouth occlusion pressure, ratio of occlusion pressure to maximal inspiratory pressure, T T0.1 , and rate of perceived breathlessness. Aerobic exercise at ventilatory threshold can induce significant improvement in respiratory muscle strength, maximal exercise capacity, and inspiratory muscle performance and decreased dyspnea perception in obese subjects. Copyright © 2017 by Daedalus Enterprises.

Characteristics and determinants of endurance cycle ergometry and six-minute walk distance in patients with COPD.

PubMed

Andrianopoulos, Vasileios; Wagers, Scott S; Groenen, Miriam T J; Vanfleteren, Lowie E; Franssen, Frits M E; Smeenk, Frank W J M; Vogiatzis, Ioannis; Wouters, Emiel F M; Spruit, Martijn A

2014-05-31

Exercise tolerance can be assessed by the cycle endurance test (CET) and six-minute walk test (6MWT) in patients with Chronic Obstructive Pulmonary Disease (COPD). We sought to investigate the characteristics of functional exercise performance and determinants of the CET and 6MWT in a large clinical cohort of COPD patients. A dataset of 2053 COPD patients (43% female, age: 66.9 ± 9.5 years, FEV1% predicted: 48.2 ± 23.2) was analyzed retrospectively. Patients underwent, amongst others, respiratory function evaluation; medical tests and questionnaires, one maximal incremental cycle test where peak work rate was determined and two functional exercise tests: a CET at 75% of peak work rate and 6MWT. A stepwise multiple linear regression was used to assess determinants. On average, patients had impaired exercise tolerance (peak work rate: 56 ± 27% predicted, 6MWT: 69 ± 17% predicted). A total of 2002 patients had CET time of duration (CET-Tend) less than 20 min while only 51 (2.5%) of the patients achieved 20 min of CET-Tend . In former patients, the percent of predicted peak work rate achieved differed significantly between men (48 ± 21% predicted) and women (67 ± 31% predicted). In contrast, CET-Tend was longer in men (286 ± 174 s vs 250 ± 153 s, p < 0.001). Also, six minute walking distance (6MWD) was higher in men compared to women, both in absolute terms as in percent of predicted (443 m, 67%predicted vs 431 m, 72%predicted, p < 0.05). Gender was associated with the CET-Tend but BMI, FEV1 and FRC were related to the 6MWD highlighting the different determinants of exercise performance between CET and 6MWT. CET-Tend is a valuable outcome of CET as it is related to multiple clinical aspects of disease severity in COPD. Gender difference should temper the interpretation of CET.

Does nebulized fentanyl relieve dyspnea during exercise in healthy man?

PubMed Central

Kotrach, Houssam G.; Bourbeau, Jean

2015-01-01

Few therapies exist for the relief of dyspnea in restrictive lung disorders. Accumulating evidence suggests that nebulized opioids selective for the mu-receptor subtype may relieve dyspnea by modulating intrapulmonary opioid receptor activity. Our respective primary and secondary objectives were to test the hypothesis that nebulized fentanyl (a mu-opioid receptor agonist) relieves dyspnea during exercise in the presence of abnormal restrictive ventilatory constraints and to identify the physiological mechanisms of this improvement. In a randomized, double-blind, placebo-controlled crossover study, we examined the effect of 250 μg nebulized fentanyl, chest wall strapping (CWS), and their interaction on detailed physiological and perceptual responses to constant work rate cycle exercise (85% of maximum incremental work rate) in 14 healthy, fit young men. By design, CWS decreased vital capacity by ∼20% and mimicked the negative consequences of a mild restrictive lung disorder on exercise endurance time and on dyspnea, breathing pattern, dynamic operating lung volumes, and diaphragmatic electromyographic and respiratory muscle function during exercise. Compared with placebo under both unrestricted control and CWS conditions, nebulized fentanyl had no effect on exercise endurance time, integrated physiological response to exercise, sensory intensity, unpleasantness ratings of exertional dyspnea. Our results do not support a role for intrapulmonary opioids in the neuromodulation of exertional dyspnea in health nor do they provide a physiological rationale for the use of nebulized fentanyl in the management of dyspnea due to mild restrictive lung disorders, specifically those arising from abnormalities of the chest wall and not affiliated with airway inflammation. PMID:26031762

[Tolerance for physical loading in relation to arterial hypertension and excess body weight in a population of 11 to 17-year-old schoolchildren].

PubMed

Il'chemko, I N; Tubol, I B; Shal'nova, S A; Zinenko, G M; Likov, A F

1983-01-01

In a cross-sectional epidemiologic study of schoolchildren aged 11-17 years, the cardiac work index at exercise was found to be higher in schoolchildren with arterial hypertension (AH) and excess body weight than in the control group. The duration of an exercise test was similar in the two groups. The higher cardiac work index at exercise may be explained by considerably higher systolic blood pressure in schoolchildren with AH and by higher heart rates in those with excess body weight.

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.

The anticipatory regulation of performance: the physiological basis for pacing strategies and the development of a perception-based model for exercise performance.

PubMed

Tucker, R

2009-06-01

During self-paced exercise, the exercise work rate is regulated by the brain based on the integration of numerous signals from various physiological systems. It has been proposed that the brain regulates the degree of muscle activation and thus exercise intensity specifically to prevent harmful physiological disturbances. It is presently proposed how the rating of perceived exertion (RPE) is generated as a result of the numerous afferent signals during exercise and serves as a mediator of any subsequent alterations in skeletal muscle activation levels and exercise intensity. A conceptual model for how the RPE mediates feedforward, anticipatory regulation of exercise performance is proposed, and this model is applied to previously described research studies of exercise in various conditions, including heat, hypoxia and reduced energy substrate availability. Finally, the application of this model to recent novel studies that altered pacing strategies and performance is described utilising an RPE clamp design, central nervous system drugs and the provision of inaccurate duration or distance feedback to exercising athletes.

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

PubMed

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

2015-12-15

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

A Pilot Study of Women’s Affective Responses to Common and Uncommon Forms of Aerobic Exercise

PubMed Central

Stevens, Courtney J.; Smith, Jane Ellen; Bryan, Angela D.

2015-01-01

Objective To test the extent to which participants exposed to an uncommon versus common exercise stimulus would result in more favourable affect at post task. Design Experimental design. Participants, (N = 120) American women aged 18–45 years, were randomly assigned to complete 30-minutes of either the uncommon (HOOP; n = 58) or common (WALK; n = 62) exercise stimulus. Main Outcome Measures Self-reported affect and intentions for future exercise were measured before and after the 30-minute exercise bout. Results Analyses of covariance (ANCOVA) were run to compare post-task affect across the HOOP and WALK conditions. At post-task, participants assigned to HOOP reported more positively valenced affect, higher ratings of positive activated affect, lower ratings of negative deactivated affect, and stronger intentions for future aerobic exercise compared to participants assigned to WALK. Conclusions Participants who completed an uncommon bout of aerobic exercise (HOOP) reported more favourable affect post-exercise, as well as stronger intentions for future exercise, compared to participants who completed a common bout of aerobic exercise (WALK). Future work using a longitudinal design is needed to understand the relationships between familiarity with an exercise stimulus, affective responses to exercise, motivation for future exercise behaviour, and exercise maintenance over time. PMID:26394246

Exercise science: research to sustain and enhance performance

NASA Astrophysics Data System (ADS)

Wingo, Jonathan E.

2013-05-01

Cardiovascular adjustments accompanying exercise in high ambient temperatures are likely responsible for diminished aerobic capacity and performance in such conditions. These adjustments include a phenomenon known as cardiovascular drift in which heart rate rises and stroke volume declines progressively over time during constant-rate exercise. A variety of factors modulate the magnitude of cardiovascular drift, e.g., elevated core and skin temperatures, dehydration, and exercise intensity. Regardless of the mode of manipulation, decreases in stroke volume associated with cardiovascular drift result in directionally and proportionally similar decreases in maximal aerobic capacity. Maximal aerobic capacity is determined by maximal heart rate, maximal tissue oxygen extraction, and maximal stroke volume. Because maximal heart rate and maximal tissue oxygen extraction are unaffected during exercise in the heat, decreased stroke volume associated with cardiovascular drift likely persists during maximal efforts and explains the decrease in maximal aerobic capacity. Decreased maximal aerobic capacity results in a greater perceptual and physiological strain accompanying any given level of work. Therefore, sustaining and enhancing performance involves sophisticated monitoring of physiological strain combined with development of countermeasures that mitigate the magnitude of deleterious phenomena like cardiovascular drift.

Pedaling rate is an important determinant of human oxygen uptake during exercise on the cycle ergometer

PubMed Central

Formenti, Federico; Minetti, Alberto E; Borrani, Fabio

2015-01-01

Estimation of human oxygen uptake () during exercise is often used as an alternative when its direct measurement is not feasible. The American College of Sports Medicine (ACSM) suggests estimating human during exercise on a cycle ergometer through an equation that considers individual's body mass and external work rate, but not pedaling rate (PR). We hypothesized that including PR in the ACSM equation would improve its prediction accuracy. Ten healthy male participants’ (age 19–48 years) were recruited and their steady-state was recorded on a cycle ergometer for 16 combinations of external work rates (0, 50, 100, and 150 W) and PR (50, 70, 90, and 110 revolutions per minute). was calculated by means of a new equation, and by the ACSM equation for comparison. Kinematic data were collected by means of an infrared 3-D motion analysis system in order to explore the mechanical determinants of . Including PR in the ACSM equation improved the accuracy for prediction of sub-maximal during exercise (mean bias 1.9 vs. 3.3 mL O2 kg−1 min−1) but it did not affect the accuracy for prediction of maximal (P > 0.05). Confirming the validity of this new equation, the results were replicated for data reported in the literature in 51 participants. We conclude that PR is an important determinant of human during cycling exercise, and it should be considered when predicting oxygen consumption. PMID:26371230

Comparison of rehydration regimens for rehabilitation of firefighters performing heavy exercise in thermal protective clothing: a report from the fireground rehab evaluation (FIRE) trial.

PubMed

Hostler, David; Bednez, James C; Kerin, Sarah; Reis, Steven E; Kong, Pui Wah; Morley, Julia; Gallagher, Michael; Suyama, Joe

2010-01-01

Performing fire suppression activities results in cardiovascular stress, hyperthermia, and hypohydration. Fireground rehabilitation (rehab) is recommended to blunt the deleterious effects of these conditions. We tested the hypothesis that three rehydration fluids provided after exercise while wearing thermal protective clothing (TPC) would produce different heart rate or core temperature responses during a second bout of exercise in TPC. On three occasions, 18 euhydrated firefighters (16 men, two women) wearing TPC completed a standardized, 50-minute bout of upper and lower body exercise in a hot room that mimicked the National Fire Protection Association (NFPA) rehabilitation guidelines of "two cylinders before rehab" (20 minutes of work, 10 minutes of recovery, 20 minutes of work). After an initial bout of exercise (bout 1), subjects were randomly assigned water, sport drink, or an intravenous (IV) infusion of normal saline equal to the amount of body mass lost during exercise. After rehydration, the subject performed a second bout of exercise (bout 2). Heart rates, core and skin temperatures, and exercise durations were compared with a two-way analysis of variance (ANOVA). Subjects were firefighters with a mean (+/- standard deviation [SD]) age of 28.2 +/- 11.3 years and a mean peak oxygen consumption (VO(2peak)) of 37.4 +/- 3.4 mL/kg/min. The mean amount of fluid provided during the rehabilitation period was 527 +/- 302 mL. No subject could complete either the pre- or postrehydration 50-minute bout of exercise. The mean (+/-SD) times to exhaustion were longer (p < 0.001) in bout 1 (25.9 +/- 12.9 min, water; 28.0 +/- 14.1 min, sport drink; 27.4 +/- 13.8 min, IV) compared with bout 2 (15.6 +/- 9.6 min, water; 14.7 +/- 8.6 min, sport drink; 15.7 +/- 8.0 min, IV) for all groups but did not differ by intervention. All subjects approached their age-predicted maximum heart rate at the end of bout 1 (180 +/- 11 bpm) and bout 2 (176 +/- 13 bpm). Core temperature rose 1.1 degrees C +/- 0.7 degrees C during bout 1 and 0.5 degrees C +/- 0.4 degrees C during bout 2. Core temperatures, heart rates, and exercise times during bout 2 did not differ between the rehydration fluids. Performances during a second bout of exercise in TPC did not differ when firefighters were rehydrated with water, sport drink, or IV normal saline when full rehydration was provided. Of concern was the inability of all subjects to complete two consecutive periods of heavy exercise in TPC, suggesting that the NFPA's "two cylinders before rehab" guideline may not be appropriate in continuous heavy work scenarios.

Comparison of rehydration regimens for rehabilitation of firefighters performing heavy exercise in thermal protective clothing: A report from the Fireground Rehab Evaluation (FIRE) trial

PubMed Central

Hostler, David; Bednez, James C; Kerin, Sarah; Reis, Steven E; Kong, Pui Wah; Morley, Julia; Gallagher, Michael; Suyama, Joe

2010-01-01

Background: Fire suppression activities results in cardiovascular stress, hyperthermia, and hypohydration. Fireground rehabilitation (rehab) is recommended to blunt the deleterious effects of these conditions. Objective: We tested the hypothesis that three rehydration fluids provided after exercise in thermal protective clothing (TPC) would produce different heart rate or core temperature responses during a second bout of exercise in TPC. Methods: On three occasions, 18 euhydrated firefighters (16 males, 2 females) wearing TPC completed a standardized, 50-minute bout of upper and lower body exercise in a hot room that mimicked the National Fire Protection Association (NFPA) rehabilitation guidelines of “two cylinders before rehab” (20 min work, 10 min recovery, 20 min work). After an initial bout of exercise, subjects were randomly assigned water, sport drink, or an intravenous (IV) infusion of normal saline equal to the amount of body mass lost during exercise. After rehydration, the subject performed a second bout of exercise. Heart rate, core and skin temperature, and exercise duration were compared with a two-way ANOVA. Results: Subjects were firefighters aged 28.2±11.3 years with a VO2peak of 37.4±3.4 ml/kg/min. 527±302 mL of fluid were provided during the rehabilitation period. No subject could complete either the pre- or post-rehydration 50-minute bout of exercise. Mean (SD) time to exhaustion (min) was longer (p<0.001) in bout 1 (25.9±12.9 min. water, 28.0±14.1 min. sport drink, 27.4±13.8 min. IV) compared to bout 2 (15.6±9.6 min. water, 14.7±8.6 min. sport drink, 15.7±8.0 min. IV) for all groups but did not differ by intervention. All subjects approached age predicted maximum heart rate at the end of bout 1 (180±11 bpm) and bout 2 (176±13 bpm). Core temperature rose 1.1±0.7°C during bout 1 and 0.5±0.4°C during bout 2. Core temperature, heart rate, and exercise time during bout 2 did not differ between rehydration fluids. Conclusions: Performance during a second bout of exercise in TPC did not differ when firefighters were rehydrated with water, sport drink, or IV normal saline when full rehydration is provided. Of concern was the inability of all subjects to complete two consecutive periods of heavy exercise in TPC suggesting the NFPA “two cylinders before rehab” guideline may not be appropriate in continuous heavy work scenarios. PMID:20095824

Studies on the exercise physiology of draft horses performed in Japan during the 1950s and 1960s.

PubMed

Hiraga, Atsushi; Sugano, Shigeru

2017-01-01

Although the total number of horses raised in Japan dramatically decreased after World War II, because draft horses were still used for farm work in paddy fields and on farms during the period of the 1950s and 1960s, a performance test for selecting better draft horses was needed. In order to determine the most suitable size of draft horses for Japanese farm conditions, the working power of horses weighing from 185 to 622 kg was evaluated by performing an endurance test, several kinds of working power tests, and maximum pulling power tests. Oxygen consumption during draft exercise was measured by the Douglas bag method in order to evaluate effects of draft workload under the conditions of different types of work (14- and 18-cm plow depths, cultivator, and tillage), traction methods (shoulder traction, shoulder-trunk traction, and chest-trunk traction), walking speeds (40, 60, 80, 100, and 120 m/min), and depths of water (0, 18, 36, and 54 cm) on energy expenditure. The relationship between energy consumption and pulse rate during exercise was also evaluated. A study of a performance test for draft horses was conducted to establish a new approach for evaluating draft horse performance using heart rate as an index. For this study, a beat meter for measuring heart rate was developed, and experimental protocols were used to evaluate the relationship between heart rate and workload. Although the research results obtained from these studies do not have particular relevance in the current day, these studies are valuable for understanding the history of equine exercise physiology in Japan.

Studies on the exercise physiology of draft horses performed in Japan during the 1950s and 1960s

PubMed Central

HIRAGA, Atsushi; SUGANO, Shigeru

2017-01-01

ABSTRACT Although the total number of horses raised in Japan dramatically decreased after World War II, because draft horses were still used for farm work in paddy fields and on farms during the period of the 1950s and 1960s, a performance test for selecting better draft horses was needed. In order to determine the most suitable size of draft horses for Japanese farm conditions, the working power of horses weighing from 185 to 622 kg was evaluated by performing an endurance test, several kinds of working power tests, and maximum pulling power tests. Oxygen consumption during draft exercise was measured by the Douglas bag method in order to evaluate effects of draft workload under the conditions of different types of work (14- and 18-cm plow depths, cultivator, and tillage), traction methods (shoulder traction, shoulder-trunk traction, and chest-trunk traction), walking speeds (40, 60, 80, 100, and 120 m/min), and depths of water (0, 18, 36, and 54 cm) on energy expenditure. The relationship between energy consumption and pulse rate during exercise was also evaluated. A study of a performance test for draft horses was conducted to establish a new approach for evaluating draft horse performance using heart rate as an index. For this study, a beat meter for measuring heart rate was developed, and experimental protocols were used to evaluate the relationship between heart rate and workload. Although the research results obtained from these studies do not have particular relevance in the current day, these studies are valuable for understanding the history of equine exercise physiology in Japan. PMID:28400701

Pulmonary and leg VO2 during submaximal exercise: implications for muscular efficiency

NASA Technical Reports Server (NTRS)

Poole, D. C.; Gaesser, G. A.; Hogan, M. C.; Knight, D. R.; Wagner, P. D.

1992-01-01

Insights into muscle energetics during exercise (e.g., muscular efficiency) are often inferred from measurements of pulmonary gas exchange. This procedure presupposes that changes of pulmonary O2 (VO2) associated with increases of external work reflect accurately the increased muscle VO2. The present investigation addressed this issue directly by making simultaneous determinations of pulmonary and leg VO2 over a range of work rates calculated to elicit 20-90% of maximum VO2 on the basis of prior incremental (25 or 30 W/min) cycle ergometry. VO2 for both legs was calculated as the product of twice one-leg blood flow (constant-infusion thermodilution) and arteriovenous O2 content difference across the leg. Measurements were made 3-5 min after each work rate imposition to avoid incorporation of the VO2 slow component above the lactate threshold. For all 17 subjects, the slope of pulmonary VO2 (9.9 +/- 0.2 ml O2.W-1.min-1) was not different (P greater than 0.05) from that for leg VO2 (9.2 +/- 0.6 ml O2.W-1.min-1). Estimation of "delta" efficiency (i.e., delta work accomplished divided by delta energy expended, calculated from slope of VO2 vs. work rate and a caloric equivalent for O2 of 4.985 cal/ml) using pulmonary VO2 measurements (29.1 +/- 0.6%) was likewise not significantly different (P greater than 0.05) from that made using leg VO2 measurements (33.7 +/- 2.4%). These data suggest that the net VO2 cost of metabolic "support" processes outside the exercising legs changes little over a relatively broad range of exercise intensities. Thus, under the conditions of this investigation, changes of VO2 measured from expired gas reflected closely those occurring within the exercising legs.

Combined short-arm centrifuge and aerobic exercise training improves cardiovascular function and physical working capacity in humans.

PubMed

Yang, Chang-Bin; Zhang, Shu; Zhang, Yu; Wang, Bing; Yao, Yong-Jie; Wang, Yong-Chun; Wu, Yan-Hong; Liang, Wen-Bin; Sun, Xi-Qing

2010-12-01

Musculoskeletal and cardiovascular deconditioning occurring in long-term spaceflight gives rise to the needs to develop new strategies to counteract these adverse effects. Short-arm centrifuge combined with ergometer has been proposed as a strategy to counteract adverse effects of microgravity. This study sought to investigate whether the combination of short-arm centrifuge and aerobic exercise training have advantages over short-arm centrifuge or aerobic exercise training alone. One week training was conducted by 24 healthy men. They were randomly divided into 3 groups: (1) short-arm centrifuge training, (2) aerobic exercise training, 40 W, and (3) combined short-arm centrifuge and aerobic exercise training. Before and after training, the cardiac pump function represented by stroke volume, cardiac output, left ventricular ejection time, and total peripheral resistance was evaluated. Variability of heart rate and systolic blood pressure were determined by spectral analysis. Physical working capacity was surveyed by near maximal physical working capacity test. The 1-week combined short-arm centrifuge and aerobic exercise training remarkably ameliorated the cardiac pump function and enhanced vasomotor sympathetic nerve modulation and improved physical working capacity by 10.9% (P<.05, n=8). In contrast, neither the short-arm centrifuge nor the aerobic exercise group showed improvements in these functions. These results demonstrate that combined short-arm centrifuge and aerobic exercise training has advantages over short-arm centrifuge or aerobic exercise training alone in influencing several physiologically important cardiovascular functions in humans. The combination of short-arm centrifuge and aerobic exercise offers a promising countermeasure to microgravity.

Cardiorespiratory parameters in draught horses before and after short term draught work pulling loads.

PubMed

Pérez, R; Recabarren, S E; Mora, G; Jara, C; Quijada, G; Hetz, E

1992-04-01

In order to establish the relationship between draught force and cardiorespiratory responses to exercise heart rate (HR), respiratory rate (RR), arterial and venous blood gases, pH, hemoglobin concentration and temperature were measured in five draught horses during rest, immediately after exercise and 30 min post-exercise under field conditions. A wagon equipped with an odometer and a hydraulic dynamometer was used for measuring distance and draught force. The wagon was loaded with 946 kg for the low load, 1,979 kg for the medium load and 2,994 kg for the high load, and drawn for a distance of 1,500 m. Draught force and load weight were linearly related. The response of the draught horse to low and medium load exercise was characterized by a moderate increase in HR, RR and temperature with no significant changes in arterial blood gases and pH. An increase in HR, RR and temperature was observed, whereas no changes in arterial PO2 and increases in venous PO2 were noticed after high load exercise. Slight increase in venous lactic acid concentration as a result of high load exercise was observed, suggesting that some anaerobic work was performed. However this was insufficient to produce changes in blood pH. The increase in metabolic requirements during the three levels of draught exercise was associated with increases in arterial hemoglobin concentration and oxygen content of blood.

Changes in extracellular muscle volume affect heart rate and blood pressure responses to static exercise

NASA Astrophysics Data System (ADS)

Baum, K.; Essfeld, D.; Stegemann, J.

To investigate the effect of μg-induced peripheral extracellular fluid reductions on heart rate and blood pressure during isometric exercise, six healthy male subjects performed three calf ergometer test with different extracellular volumes of working muscles. In all tests, body positions during exercise were identical (supine with the knee joint flexed to 900). After a pre-exercise period of 25 min, during which calf volumes were manipulated, subjects had to counteract an external force of 180 N for 5 min. During the pre-exercise period three different protocols were applied. Test A: Subjects rested in the exercise position; test B: Body position was the same as in A but calf volume was increased by venous congestion (cuffs inflated to 80 mm Hg); test C: Calf volumes were decreased by a negative hydrostatic pressure (calves about 40 cm above heart level with the subjects supine). To clamp the changed calf volumes in tests B and C, cuffs were inflated to 300 mm Hg 5 min before the onset of exercise. This occlusion was maintained until termination of exercise. Compared to tests A and B, the reduced volume of test C led to significant increases in heart rate and blood pressure during exercise. Oxygen uptake did not exceed resting levels in B and C until cuffs were deflated, indicating that exclusively calf muscles contributed to the neurogenic peripheral drive. It is concluded that changes in extracellular muscle volume have to be taken into account when comparing heart rate and blood pressure during lg- and μg- exercise.

Effects of pre-cooling procedures on intermittent-sprint exercise performance in warm conditions.

PubMed

Duffield, Rob; Marino, Frank E

2007-08-01

The aim of this study was to determine whether pre-cooling procedures improve both maximal sprint and sub-maximal work during intermittent-sprint exercise. Nine male rugby players performed a familiarisation session and three testing sessions of a 2 x 30-min intermittent sprint protocol, which consisted of a 15-m sprint every min separated by free-paced hard-running, jogging and walking in 32 degrees C and 30% humidity. The three sessions included a control condition, Ice-vest condition and Ice-bath/Ice-vest condition, with respective cooling interventions imposed for 15-min pre-exercise and 10-min at half-time. Performance measures of sprint time and % decline and distance covered during sub-maximal exercise were recorded, while physiological measures of core temperature (T (core)), mean skin temperature (T (skin)), heart rate, heat storage, nude mass, rate of perceived exertion, rate of thermal comfort and capillary blood measures of lactate [La(-)], pH, Sodium (Na(+)) and Potassium (K(+)) were recorded. Results for exercise performance indicated no significant differences between conditions for the time or % decline in 15-m sprint efforts or the distance covered during sub-maximal work bouts; however, large effect size data indicated a greater distance covered during hard running following Ice-bath cooling. Further, lowered T (core), T (skin), heart rate, sweat loss and thermal comfort following Ice-bath cooling than Ice-vest or Control conditions were present, with no differences present in capillary blood measures of [La(-)], pH, K(+) or Na(+). As such, the ergogenic benefits of effective pre-cooling procedures in warm conditions for team-sports may be predominantly evident during sub-maximal bouts of exercise.

On the kinetics of anaerobic power

PubMed Central

2012-01-01

Background This study investigated two different mathematical models for the kinetics of anaerobic power. Model 1 assumes that the work power is linear with the work rate, while Model 2 assumes a linear relationship between the alactic anaerobic power and the rate of change of the aerobic power. In order to test these models, a cross country skier ran with poles on a treadmill at different exercise intensities. The aerobic power, based on the measured oxygen uptake, was used as input to the models, whereas the simulated blood lactate concentration was compared with experimental results. Thereafter, the metabolic rate from phosphocreatine break down was calculated theoretically. Finally, the models were used to compare phosphocreatine break down during continuous and interval exercises. Results Good similarity was found between experimental and simulated blood lactate concentration during steady state exercise intensities. The measured blood lactate concentrations were lower than simulated for intensities above the lactate threshold, but higher than simulated during recovery after high intensity exercise when the simulated lactate concentration was averaged over the whole lactate space. This fit was improved when the simulated lactate concentration was separated into two compartments; muscles + internal organs and blood. Model 2 gave a better behavior of alactic energy than Model 1 when compared against invasive measurements presented in the literature. During continuous exercise, Model 2 showed that the alactic energy storage decreased with time, whereas Model 1 showed a minimum value when steady state aerobic conditions were achieved. During interval exercise the two models showed similar patterns of alactic energy. Conclusions The current study provides useful insight on the kinetics of anaerobic power. Overall, our data indicate that blood lactate levels can be accurately modeled during steady state, and suggests a linear relationship between the alactic anaerobic power and the rate of change of the aerobic power. PMID:22830586

Measuring the effects of massage on exercise performance and cardiopulmonary response in children with and without heart disease: a pilot study.

PubMed

Beider, Shay; Boulanger, Karen T; Joshi, Milind; Pan, Yann Ping; Chang, Ruey-Kang R

2010-09-28

Congenital heart disease, a common and serious birth defect, affects 8 per 1000 live-born infants. Decreased exercise capacity and development of obesity is common in this population. These children may benefit from therapies, such as massage therapy, that could enhance cardiovascular and skeletal muscle function when they exercise. A pilot study conducted at the pediatric cardiology clinic of the Mattel Children's Hospital of the University of California-Los Angeles examined the safety and feasibility of measuring the effects of pre-exercise massage on exercise performance and cardiopulmonary response in children with and without heart disease. SIXTEEN CHILDREN (MEAN AGE: 9.2 ± 2.2 years) participated in the study. Ten participants had various forms of heart disease, and six children were healthy. A female certified massage therapist with specialized training in pediatric massage provided a 30-minute massage to the participants. Using a standard protocol, each participant underwent two exercise tests: one test with and one without pre-exercise massage. Heart rate, blood pressure, and oxygen uptake (VO(2)) were measured in the participants. All recruited participants completed the study. No adverse events occurred during any of the exercise tests or massage sessions. Measurements during exercise with or without a preceding massage were compared, and the pre-exercise massage condition yielded a significantly higher heart rate and higher minute ventilation. Measurements during exercise in children with heart disease and in healthy participants showed no significant differences in peak heart rate, blood pressure, peak VO(2), peak work rate, minute ventilation, or respiratory quotient. In this study, peak heart rate, peak VO(2), and peak minute ventilation were higher when children received a massage before exercise testing. Larger studies will be needed to investigate the strength of this finding. Future studies should include measurements of anxiety and psychological factors in addition to cardiopulmonary measures.

Work-rate-guided exercise testing in patients with incomplete spinal cord injury using a robotics-assisted tilt-table.

PubMed

Laubacher, Marco; Perret, Claudio; Hunt, Kenneth J

2015-01-01

Robotics-assisted tilt-table (RTT) technology allows neurological rehabilitation therapy to be started early thus alleviating some secondary complications of prolonged bed rest. This study assessed the feasibility of a novel work-rate-guided RTT approach for cardiopulmonary training and assessment in patients with incomplete spinal cord injury (iSCI). Three representative subjects with iSCI at three distinct stages of primary rehabilitation completed an incremental exercise test (IET) and a constant load test (CLT) on a RTT augmented with integrated leg-force and position measurement and visual work rate feedback. Feasibility assessment focused on: (i) implementation, (ii) limited efficacy testing, (iii) acceptability. (i) All subjects were able follow the work rate target profile by adapting their volitional leg effort. (ii) During the IETs, peak oxygen uptake above rest was 304, 467 and 1378 ml/min and peak heart rate (HR) was 46, 32 and 65 beats/min above rest (subjects A, B and C, respectively). During the CLTs, steady-state oxygen uptake increased by 42%, 38% and 162% and HR by 12%, 20% and 29%. (iii) All exercise tests were tolerated well. The novel work-rate guided RTT intervention is deemed feasible for cardiopulmonary training and assessment in patients with iSCI: substantial cardiopulmonary responses were observed and the approach was found to be tolerable and implementable. Implications for Rehabilitation Work-rate guided robotics-assisted tilt-table technology is deemed feasible for cardiopulmonary assessment and training in patients with incomplete spinal cord injury. Robotics-assisted tilt-tables might be a good way to start with an active rehabilitation as early as possible after a spinal cord injury. During training with robotics-assisted devices the active participation of the patients is crucial to strain the cardiopulmonary system and hence gain from the training.

Hemodynamic responses to small muscle mass exercise in heart failure patients with reduced ejection fraction

PubMed Central

Barrett-O'Keefe, Zachary; Lee, Joshua F.; Berbert, Amanda; Witman, Melissa A. H.; Nativi-Nicolau, Jose; Stehlik, Josef; Richardson, Russell S.

2014-01-01

To better understand the mechanisms responsible for exercise intolerance in heart failure with reduced ejection fraction (HFrEF), the present study sought to evaluate the hemodynamic responses to small muscle mass exercise in this cohort. In 25 HFrEF patients (64 ± 2 yr) and 17 healthy, age-matched control subjects (64 ± 2 yr), mean arterial pressure (MAP), cardiac output (CO), and limb blood flow were examined during graded static-intermittent handgrip (HG) and dynamic single-leg knee-extensor (KE) exercise. During HG exercise, MAP increased similarly between groups. CO increased significantly (+1.3 ± 0.3 l/min) in the control group, but it remained unchanged across workloads in HFrEF patients. At 15% maximum voluntary contraction (MVC), forearm blood flow was similar between groups, while HFrEF patients exhibited an attenuated increase at the two highest intensities compared with controls, with the greatest difference at the highest workload (352 ± 22 vs. 492 ± 48 ml/min, HFrEF vs. control, 45% MVC). During KE exercise, MAP and CO increased similarly across work rates between groups. However, HFrEF patients exhibited a diminished leg hyperemic response across all work rates, with the most substantial decrement at the highest intensity (1,842 ± 64 vs. 2,675 ± 81 ml/min; HFrEF vs. control, 15 W). Together, these findings indicate a marked attenuation in exercising limb perfusion attributable to impairments in peripheral vasodilatory capacity during both arm and leg exercise in patients with HFrEF, which likely plays a role in limiting exercise capacity in this patient population. PMID:25260608

[Health behaviors by job stress level in large-sized company with male and female workers].

PubMed

Park, Hyunju; Jung, Hye-Sun

2010-12-01

This study was done to investigate differences in health behaviors by job stress level in male and female workers in a large-sized company. Participants were 576 male and 228 female workers who completed questionnaires. Job stress was measured using the 'Short Form Korean Occupational Stress Scale (SF-KOSS)'. Health behaviors included smoking, alcohol consumption, regular exercise, and diet. Frequency, mean, SD, chi-square test, and multivariate logistic regression using SAS version 9.1 were used to analyze data. Smoking, drinking and regular exercise rates were not different by job stress level in male or female workers. Only regular diet was significantly different by job stress level in male and female workers. From multivariate analysis, the alcohol consumption rates for female workers differed by marital status. Regular exercise rate was significantly related to age for male workers and type of employment for female workers. After adjusting for demographic and work-related characteristics, regular diet significantly differed by shift work for male workers and marital status and shift work for female workers. The findings of the study indicate that nursing interventions should be developed to manage job stress to improve diet habits for male and female workers in large-sized companies.

The effect of endurance training on the ventilatory response to exercise in elite cyclists.

PubMed

Hoogeveen, A R

2000-05-01

The purpose of this study was to investigate the effects of endurance training on the ventilatory response to acute incremental exercise in elite cyclists. Fifteen male elite cyclists [mean (SD) age 24.3 (3.3) years, height 179 (6) cm, body mass 71.1 (7.6) kg, maximal oxygen consumption (VO2max) 69 (7) ml x min(-1) x kg(-1)] underwent two exercise tests on a cycle ergometer. The first test was assessed in December, 6 weeks before the beginning of the cycling season. The second test was performed in June, in the middle of the season. During this period the subjects were expected to be in a highly endurance-trained state. The ventilatory response was assessed during an incremental exercise test (20 W x min(-1)). Oxygen consumption (VO2), carbon dioxide production (VCO2), minute ventilation (VE), and heart rate (HR) were assessed at the following points during the test: at workloads of 200 W, 250 W, 300 W, 350 W, 400 W and at the subject's maximal workload, at a respiratory exchange ratio (R) of 1, and at the ventilatory threshold (Th(vent)) determined using the V-slope-method. Post-training, the mean (SD) VO2max was increased from the pre-training level of 69 (7) ml x min(-1) x kg(-1) (range 61.4-78.6) to 78 (6) ml x min(-1) x kg(-1) (range 70.5-86.3). The mean post-training VO2 was significantly higher than the pre training value (P < 0.01) at all work rates, at Th(vent) and at R = 1. VO2 was also higher at all work rates except for 200 W and 250 W. VE was significantly higher at Th(vent) and R = 1. Training had no effect on HR at all workloads examined. An explanation for the higher VO2 cost for the same work rate may be that in the endurance-trained state, the adaptation to an exercise stimulus with higher intensity is faster than for the less-trained state. Another explanation may be that at the same work rate, in the less-endurance-trained state power is generated using a significantly higher anaerobic input. The results of this study suggest the following practical recommendations for training management in elite cyclists: (1) the VO2 for a subject at the same work rate may be an indicator of the endurance-trained state (i.e., the higher the VO2, the higher the endurance-trained capacity), and (2) the need for multiple exercise tests for determining the HR at Th(vent) during a cycling season is doubtful since at Th(vent) this parameter does not differ much following endurance training.

Effect of Exercise Training and +Gz Acceleration Training on Men

NASA Technical Reports Server (NTRS)

Greenleaf, John E.; Simonson, Shawn R.; Stocks, Jodie M.; Evans, Joyce; Knapp, Charles F.; Cowell, Stephenie A.; Pemberton, Kendra N.; Wilson, Heather W.; Vener, Jamie M.; Evetts, Simon N.

2001-01-01

Countermeasures for reduction in work capacity (maximal oxygen uptake and strength) during spaceflight and enhanced orthostatic intolerance during re-entry, landing and egress from the return vehicle are continuing problems. The purpose for this study was to test the hypothesis that passive-acceleration training; supine, interval, exercise plus acceleration training and exercise combined with acceleration training would improve orthostatic tolerance in ambulatory men; and that addition of the aerobic exercise conditioning would not alter this improved tolerance from that of passive-acceleration training. Seven men (24-38 yr) underwent "Passive" training on the Ames human-powered centrifuge (HPC) for 30 min, "Exercise" training on the cycle ergometer with constant +Gz acceleration; and "Combined" exercise training at 40% to 90% of the HPC +Gz(max) exercise level. Maximal supine exercise loads increased significant (P<0.05) by 8.3% (Passive), 12.6% (Exercise), and by 15.4% (Combined) after training, but their post-training maximal oxygen uptakes and maximal heart rates were unchanged. Maximal time to fatigue (endurance) was unchanged with Passive was increased (P<0.05) with Exercise and Combined training. Thus, the exercise in the Exercise and Combined training Phases resulted in greater maximal loads and endurance without effect on maximal oxygen uptake or heart rate. There was a 4% to 6% increase (P<0.05) in all four quadriceps muscle volumes (right and left) after post-Combined training. Resting pre-tilt heart rate was elevated by 12.9% (P<0.05) only after Passive training suggesting that the exercise training attenuated the HR response. Plasma volume (% Delta) was uniformly decreased by 8% to 14% (P<0.05) at tilt-tolerance pre- vs. post-training indicating essentially no effect of training on the level of hypovolemia. Post-training tilt-tolerance time and heart rate were increased (P<0.05) only with Passive training by 37.8% and by 29.1%, respectively. Thus, addition of exercise training appeared to attenuate the increased Passive tilt-tolerance.

Effect of beta-adrenergic blockade with timolol on myocardial blood flow during exercise after myocardial infarction in the dog.

PubMed

Herzog, C A; Aeppli, D P; Bache, R J

1984-12-01

The effect of beta-adrenergic blockade with timolol (40 micrograms/kg) on myocardial blood flow during rest and graded treadmill exercise was assessed in 12 chronically instrumented dogs 10 to 14 days after myocardial infarction was produced by acute left circumflex coronary artery occlusion. During exercise at comparable external work loads, the heart rate-systolic blood pressure product was significantly decreased after timilol, with concomitant reductions of myocardial blood flow in normal, border and central ischemic areas (p less than 0.001) and increases in subendocardial/subepicardial blood flow ratios (p less than 0.05). In addition to the blunted chronotropic response to exercise, timolol exerted an effect on myocardial blood flow that was not explained by changes in heart rate or blood pressure. At comparable rate-pressure products during exercise, total myocardial blood flow was 24% lower after timolol (p less than 0.02) and flow was redistributed from subepicardium to subendocardium in all myocardial regions. Thus, timolol altered myocardial blood flow during exercise by two separate mechanisms: a negative chronotropic effect, and a significant selective reduction of subepicardial perfusion independent of changes in heart rate or blood pressure with transmural redistribution of flow toward the subendocardium.

The Digital Astronaut Project Bone Remodeling Model

NASA Technical Reports Server (NTRS)

Pennline, James A.; Mulugeta, Lealem; Lewandowski, Beth E.; Thompson, William K.; Sibonga, Jean D.

2014-01-01

Under the conditions of microgravity, astronauts lose bone mass at a rate of 1% to 2% a month, particularly in the lower extremities such as the proximal femur: (1) The most commonly used countermeasure against bone loss has been prescribed exercise, (2) However, current exercise countermeasures do not completely eliminate bone loss in long duration, 4 to 6 months, spaceflight, (3,4) leaving the astronaut susceptible to early onset osteoporosis and a greater risk of fracture later in their lives. The introduction of the Advanced Resistive Exercise Device, coupled with improved nutrition, has further minimized the 4 to 6 month bone loss. But further work is needed to implement optimal exercise prescriptions, and (5) In this light, NASA's Digital Astronaut Project (DAP) is working with NASA physiologists to implement well-validated computational models that can help understand the mechanisms of bone demineralization in microgravity, and enhance exercise countermeasure development.

Oxygen Uptake Responses to Submaximal Exercise Loads Do Not Change During Long-Duration Space Flight

NASA Technical Reports Server (NTRS)

Moore, Alan D., Jr.; Evetts, Simon N.; Feiveson, Alan H.; Lee, S. M. C.; McCleary, Frank A.; Platts, Steven H.; Ploutz-Snyder, Lori

2011-01-01

In previous publications we have reported that the heart rate (HR) responses to graded submaximal exercise tests are elevated during long-duration International Space Station (ISS) flights. Furthermore, the elevation in HR appears greater earlier, rather than later, during the missions. A potential confounder in the interpretation of HR results from graded exercise tests on ISS is that the cycle ergometer used (CEVIS) is vibration-isolated from the station structure. This feature causes the CEVIS assembly to sway slightly during its use and debriefing comments by some crewmembers indicate that there is a "learning curve" associated with CEVIS use. Therefore, one could not exclude the possibility that the elevated HRs experienced in the early stages of ISS missions were related to a lowered metabolic efficiency of CEVIS exercise that would raise the submaximal oxygen uptake (VO2) associated with graded exercise testing work rates.

Effect of spinning workouts on affect.

PubMed

Szabo, Attila; Gáspár, Zoltán; Kiss, Nikolett; Radványi, Alexandra

2015-06-01

Numerous physical exercises trigger positive changes in affect after relatively short workouts. Spinning, also known as indoor-cycling, is a very popular form of exercise, especially among women, but its impact on affect have not been examined to date. The purpose of the current work was to investigate the possible benefits of spinning on affect in self-controlled and in instructor-led exercise sessions. Using baseline measures and pre- to post-exercise design with a psychometrically validated questionnaire, the net effects of spinning (without music) on positive- and negative-affect were measured in two exercise conditions: (1) self-controlled workout (i.e. without an instructor) and (2) instructor-led workout. After both conditions, 18 women rated the extent which they enjoyed the exercise session on a 10-point Likert scale. The findings revealed that positive affect increased while negative affect decreased after both workouts. Exerted effort, measured through the heart rate, did not differ between the two conditions. However, participants enjoyed more the instructor-led exercise session than the self-regulated workout (effect size, Cohen's d = 0.93). This research reveals that spinning improves post-exercise affect, even without music and regardless of instructor's presence. Therefore, it demonstrates the net benefits of this popular exercise on affect.

Rate of utilization of a given fraction of W' (the curvature constant of the power-duration relationship) does not affect fatigue during severe-intensity exercise.

PubMed

de Souza, Kristopher Mendes; Dekerle, Jeanne; Salvador, Paulo Cesar do Nascimento; de Lucas, Ricardo Dantas; Guglielmo, Luiz Guilherme Antonacci; Greco, Camila Coelho; Denadai, Benedito Sérgio

2016-04-01

What is the central question of this study? Does the rate of utilization of W' (the curvature constant of the power-duration relationship) affect fatigue during severe-intensity exercise? What is the main finding and its importance? The magnitude of fatigue after two severe-intensity exercises designed to deplete the same fraction of W' (70%) at two different rates of utilization (fast versus slow) was similar after both exercises. Moreover, the magnitude of fatigue was related to critical power (CP), supporting the contention that CP is a key determinant in fatigue development during high-intensity exercise. Thus, the CP model is a suitable approach to investigate fatigue mechanisms during high-intensity exercise. The depletion of W' (the curvature constant of the power-duration relationship) seems to contribute to fatigue during severe-intensity exercise. Therefore, the aim of this study was to determine the effect of a fast versus a slow rate of utilization of W' on the occurrence of fatigue within the severe-intensity domain. Fifteen healthy male subjects performed tests to determine the critical power, W' and peak torque in the control condition (TCON ) and immediately after two fatiguing work rates (THREE and TEN) set to deplete 70% W' in either 3 (TTHREE ) or 10 min (TTEN ). The TTHREE and TTEN were significantly reduced (F = 19.68, P = 0.01) in comparison to TCON . However, the magnitude of reduction in peak torque (TTHREE  = -19.8 ± 10.1% versus TTEN  = -16.8 ± 13.3%) was the same in the two fatiguing exercises (t = -0.76, P = 0.46). There was a significant inverse relationship between the critical power and the reduction in peak torque during both THREE (r = -0.49, P = 0.03) and TEN (r = -0.62, P = 0.02). In contrast, the W' was not significantly correlated with the reduction in peak torque during both THREE (r = -0.14, P = 0.33) and TEN (r = -0.30, P = 0.10). Thus, fatigue following severe-intensity exercises performed at different rates of utilization of W' was similar when the same work was done above the critical power (i.e. same amount of W' used). © 2016 The Authors. Experimental Physiology © 2016 The Physiological Society.

Sweat Rates During Continuous and Interval Aerobic Exercise: Implications for NASA Multipurpose Crew Vehicle (MPCV) Missions

NASA Technical Reports Server (NTRS)

Ryder, Jeffrey W.; Scott, Jessica; Ploutz-Snyder, Robert; Ploutz-Snyder, Lori L.

2016-01-01

Aerobic deconditioning is one of the effects spaceflight. Impaired crewmember performance due to loss of aerobic conditioning is one of the risks identified for mitigation by the NASA Human Research Program. Missions longer than 8 days will involve exercise countermeasures including those aimed at preventing the loss of aerobic capacity. The NASA Multipurpose Crew Vehicle (MPCV) will be NASA's centerpiece architecture for human space exploration beyond low Earth orbit. Aerobic exercise within the small habitable volume of the MPCV is expected to challenge the ability of the environmental control systems, especially in terms of moisture control. Exercising humans contribute moisture to the environment by increased respiratory rate (exhaling air at 100% humidity) and sweat. Current acceptable values are based on theoretical models that rely on an "average" crew member working continuously at 75% of their aerobic capacity (Human Systems Integration Requirements Document). Evidence suggests that high intensity interval exercise for much shorter durations are equally effective or better in building and maintaining aerobic capacity. This investigation will examine sweat and respiratory rates for operationally relevant continuous and interval aerobic exercise protocols using a variety of different individuals. The results will directly inform what types of aerobic exercise countermeasures will be feasible to prescribe for crewmembers aboard the MPCV.

Health-related effects of worksite interventions involving physical exercise and reduced workhours.

PubMed

von Thiele Schwarz, Ulrica; Lindfors, Petra; Lundberg, Ulf

2008-06-01

This study examined the health-related effects of two worksite interventions, physical exercise and reduced workhours, on women employed in dentistry. Six workplaces were randomized to one of the following three conditions: (i) 2.5 hours of weekly, mandatory physical exercise of middle-to-high intensity to be performed during workhours (N=62), (ii) a reduction of full-time weekly workhours from 40 to 37.5 hours (N=50), and (iii) reference. In all, 177 women participated. Biomarkers and self-ratings in questionnaires were obtained before the intervention (T (1)), and six (T (2)) and 12 months (T (3)) after the intervention. The results showed increased levels of physical activity and exercise in all of the groups, the level of physical exercise being significantly greater in the physical exercise group. Repeated-measures analyses of variance using data from T (1)and T (3)for biological measures and all three time points for self-ratings produced significant interaction effects for glucose, waist-to-hip ratio, and work ability and clear trends for general symptoms and upper-extremity disorders. Posthoc analyses showed that the results of the health-related measures differed between the interventions, decreased glucose and upper-extremity disorders in the exercise group, and increased high-density lipoprotein and waist-to-hip ratio among those working reduced hours. These results show that the two interventions had small and varied effects on biomarkers and self-reports of different aspects of health among women. It is suggested that interventions involving a modest reduction in workhours seem to be more effective if these hours are used for physical exercise.

Effect of workplace- versus home-based physical exercise on pain in healthcare workers: study protocol for a single blinded cluster randomized controlled trial

PubMed Central

2014-01-01

Background The prevalence and consequences of musculoskeletal pain is considerable among healthcare workers, allegedly due to high physical work demands of healthcare work. Previous investigations have shown promising results of physical exercise for relieving pain among different occupational groups, but the question remains whether such physical exercise should be performed at the workplace or conducted as home-based exercise. Performing physical exercise at the workplace together with colleagues may be more motivating for some employees and thus increase adherence. On the other hand, physical exercise performed during working hours at the workplace may be costly for the employers in terms of time spend. Thus, it seems relevant to compare the efficacy of workplace- versus home-based training on musculoskeletal pain. This study is intended to investigate the effect of workplace-based versus home-based physical exercise on musculoskeletal pain among healthcare workers. Methods/Design This study was designed as a cluster randomized controlled trial performed at 3 hospitals in Copenhagen, Denmark. Clusters are hospital departments and hospital units. Cluster randomization was chosen to increase adherence and avoid contamination between interventions. Two hundred healthcare workers from 18 departments located at three different hospitals is allocated to 10 weeks of 1) workplace based physical exercise performed during working hours (using kettlebells, elastic bands and exercise balls) for 5 × 10 minutes per week and up to 5 group-based coaching sessions, or 2) home based physical exercise performed during leisure time (using elastic bands and body weight exercises) for 5 × 10 minutes per week. Both intervention groups will also receive ergonomic instructions on patient handling and use of lifting aides etc. Inclusion criteria are female healthcare workers working at a hospital. Average pain intensity (VAS scale 0-10) of the back, neck and shoulder (primary outcome) and physical exertion during work, social capital and work ability (secondary outcomes) is assessed at baseline and 10-week follow-up. Further, postural balance and mechanical muscle function is assessed during clinical examination at baseline and follow-up. Discussion This cluster randomized trial will investigate the change in self-rated average pain intensity in the back, neck and shoulder after either 10 weeks of physical exercise at the workplace or at home. Trial registration ClinicalTrials.gov (NCT01921764). PMID:24708570

Effect of workplace- versus home-based physical exercise on pain in healthcare workers: study protocol for a single blinded cluster randomized controlled trial.

PubMed

Jakobsen, Markus D; Sundstrup, Emil; Brandt, Mikkel; Kristensen, Anne Zoëga; Jay, Kenneth; Stelter, Reinhard; Lavendt, Ebbe; Aagaard, Per; Andersen, Lars L

2014-04-07

The prevalence and consequences of musculoskeletal pain is considerable among healthcare workers, allegedly due to high physical work demands of healthcare work. Previous investigations have shown promising results of physical exercise for relieving pain among different occupational groups, but the question remains whether such physical exercise should be performed at the workplace or conducted as home-based exercise. Performing physical exercise at the workplace together with colleagues may be more motivating for some employees and thus increase adherence. On the other hand, physical exercise performed during working hours at the workplace may be costly for the employers in terms of time spend. Thus, it seems relevant to compare the efficacy of workplace- versus home-based training on musculoskeletal pain. This study is intended to investigate the effect of workplace-based versus home-based physical exercise on musculoskeletal pain among healthcare workers. This study was designed as a cluster randomized controlled trial performed at 3 hospitals in Copenhagen, Denmark. Clusters are hospital departments and hospital units. Cluster randomization was chosen to increase adherence and avoid contamination between interventions. Two hundred healthcare workers from 18 departments located at three different hospitals is allocated to 10 weeks of 1) workplace based physical exercise performed during working hours (using kettlebells, elastic bands and exercise balls) for 5 × 10 minutes per week and up to 5 group-based coaching sessions, or 2) home based physical exercise performed during leisure time (using elastic bands and body weight exercises) for 5 × 10 minutes per week. Both intervention groups will also receive ergonomic instructions on patient handling and use of lifting aides etc. Inclusion criteria are female healthcare workers working at a hospital. Average pain intensity (VAS scale 0-10) of the back, neck and shoulder (primary outcome) and physical exertion during work, social capital and work ability (secondary outcomes) is assessed at baseline and 10-week follow-up. Further, postural balance and mechanical muscle function is assessed during clinical examination at baseline and follow-up. This cluster randomized trial will investigate the change in self-rated average pain intensity in the back, neck and shoulder after either 10 weeks of physical exercise at the workplace or at home. ClinicalTrials.gov (NCT01921764).

Comparison of arterial potassium and ventilatory dynamics during sinusoidal work rate variation in man.

PubMed Central

Casaburi, R; Stringer, W W; Singer, E

1995-01-01

1. The mechanisms underlying the exercise hyperpnoea have been difficult to define. Recently it has been suggested that exercise ventilation (VE) changes in proportion to changes in arterial potassium concentration ([K+]a). Similar VE and [K+]a time courses following work rate changes have been cited as supporting evidence. This study compared [K+]a and VE dynamics during moderate exercise in man. 2. We observed VE and gas exchange responses in five healthy men to sinusoidal work rate variation between 25 and approximately 105 W. Tests of approximately 30 min duration were performed at sinusoidal periods of 9, 6 and 3 min and in the steady state. In each test, during two or three sine periods, arterial blood was sampled (24 per test) and analysed for [K+] and blood gases. Response amplitude and phase (relative to work rate) were determined for each variable. 3. [K+]a fluctuated in response to sinusoidal work rate forcing with mean-to-peak amplitude averaging 0.15 mmol 1(-1). However, among tests, VE amplitude and phase were not highly correlated with [K+]a (r = 0.36 and 0.67, respectively). Further, average [K+]a amplitude in the 9 and 6 min sinusoidal studies tended to exceed the steady-state amplitude, while average VE amplitude fell progressively with increasing forcing frequency. The dissimilar dynamics of [K+]a and VE seem inconsistent with a major role for [K+]a as a proportional controller of ventilation during non-steady state moderate exercise in man. 4. Among tests, VE and CO2 output (VCO2) amplitude and phase were closely correlated (r = 0.87 and 0.94, respectively). Further, arterial CO2 pressure (Pa,CO2) and arterial pH(pHa) did not fluctuate significantly in ten of twenty and thirteen of twenty studies, respectively. In tests where sinusoidal fluctuation was detected, amplitude averaged 1.1 mmHg and 0.008 units, respectively. Thus VE demonstrated a close dynamic coupling to CO2 output, with consequent tight regulation of Pa,CO2 and pHa. PMID:7666376

Post-exercise ketosis.

PubMed Central

Koeslag, J H; Noakes, T D; Sloan, A W

1980-01-01

1. The effect of exercise on blood ketone body concentrations was studied in trained athletes and in sedentary subjects pedalling a bicycle ergometer. 2. Although the untrained subjects had higher heart rates and blood lactate concentrations at the same work load as the athletes, neither group developed ketonaemia even after intense or prolonged exercise. 3. Older subjects developed post-exercise ketonaemia, reaching maximum about 3 hr after exercise. 4. A high-carbohydrate diet before the exercise could prevent the onset of post-exercise ketonaemia and a low-carbohydrate diet enhanced it. The highest post-exercise blood ketone levels were recorded in marathon runners after a "glycogen-stripping' regimen. 5. Concentrations of free fatty acids, glucose, growth hormone and insulin in blood after exercise followed different patterns from that of ketones. 6. Post-exercise ketosis, when it occurs in untrained subjects, may be due to a lower carbohydrate intake than that of athletes. PMID:6997456

Heat exposure increases circulating fatty acids but not lipid oxidation at rest and during exercise.

PubMed

O'Hearn, Katharine; Tingelstad, Hans Christian; Blondin, Denis; Tang, Vera; Filion, Lionel G; Haman, François

2016-01-01

Alterations in lipid oxidation during exercise have been well studied, but limited data exists on the effects of passive heat exposure and exercise in the heat on changes in lipid oxidation. This study was designed to examine: (1) the effects of heat exposure on lipid metabolism during passive heating and subsequent exercise in the heat by focusing on changes in whole-body lipid oxidation and plasma lipid concentrations, and (2) the effects of extended passive pre-heating on exercise performance in the heat. Male participants (n=8) were passively heated for 120 min at 42 °C, then exercised on a treadmill in the same temperature at 50% V̇O2 max for 30 min (HEAT). This same procedure was followed on a separate occasion at 23 °C (CON). Results showed that lipid oxidation rates were not different between HEAT and CON during passive heating or exercise. However, non-esterified fatty acid (NEFA) concentrations were significantly higher following passive heating (618 µM, 95% CI: 479-757) compared to CON (391 µM, 95% CI: 270-511). The same trend was observed following exercise (2036 µM, 95% CI: 1604-2469 for HEAT and 1351 µM, 95% CI: 1002-1699). Triacylglycerol, phospholipid and cholesterol levels were not different between HEAT and CON at any point. Four of 8 participants could not complete 30 min of exercise in HEAT, resulting in a 14% decline in total external work. Rate of perceived exertion over the final 5 min of exercise was higher in HEAT (9.5) than CON (5). We conclude that: (1) heat exposure results in increased circulating NEFA at rest and during exercise without changes in whole-body lipid utilization, and (2) passive pre-heating reduces work capacity during exercise in the heat and increases the perceived intensity of a given workload. Copyright © 2015 Elsevier Ltd. All rights reserved.

Role of right ventricle and dynamic pulmonary hypertension on determining ΔVO2/ΔWork Rate flattening: insights from cardiopulmonary exercise test combined with exercise echocardiography.

PubMed

Bandera, Francesco; Generati, Greta; Pellegrino, Marta; Donghi, Valeria; Alfonzetti, Eleonora; Gaeta, Maddalena; Villani, Simona; Guazzi, Marco

2014-09-01

Several cardiovascular diseases are characterized by an impaired O2 kinetic during exercise. The lack of a linear increase of Δoxygen consumption (VO2)/ΔWork Rate (WR) relationship, as assessed by expired gas analysis, is considered an indicator of abnormal cardiovascular efficiency. We aimed at describing the frequency of ΔVO2/ΔWR flattening in a symptomatic population of cardiac patients, characterizing its functional profile, and testing the hypothesis that dynamic pulmonary hypertension and right ventricular contractile reserve play a major role as cardiac determinants. We studied 136 patients, with different cardiovascular diseases, referred for exertional dyspnoea. Cardiopulmonary exercise test combined with simultaneous exercise echocardiography was performed using a symptom-limited protocol. ΔVO2/ΔWR flattening was observed in 36 patients (group A, 26.5% of population) and was associated with a globally worse functional profile (reduced peak VO2, anaerobic threshold, O2 pulse, impaired VE/VCO2). At univariate analysis, exercise ejection fraction, exercise mitral regurgitation, rest and exercise tricuspid annular plane systolic excursion, exercise systolic pulmonary artery pressure, and exercise cardiac output were all significantly (P<0.05) impaired in group A. The multivariate analysis identified exercise systolic pulmonary artery pressure (odds ratio, 1.06; confidence interval, 1.01-1.11; P=0.01) and exercise tricuspid annular plane systolic excursion (odds ratio, 0.88; confidence interval, 0.80-0.97; P=0.01) as main cardiac determinants of ΔVO2/ΔWR flattening; female sex was strongly associated (odds ratio, 6.10; confidence interval, 2.11-17.7; P<0.01). In patients symptomatic for dyspnea, the occurrence of ΔVO2/ΔWR flattening reflects a significantly impaired functional phenotype whose main cardiac determinants are the excessive systolic pulmonary artery pressure increase and the reduced peak right ventricular longitudinal systolic function. © 2014 American Heart Association, Inc.

Oxidative stress response in trained men following repeated squats or sprints.

PubMed

Bloomer, Richard J; Falvo, Michael J; Fry, Andrew C; Schilling, Brian K; Smith, Webb A; Moore, Christopher A

2006-08-01

The purpose of this investigation was to measure the oxidative stress response to similarly matched work bouts of squat and sprint exercise. Twelve anaerobically trained men performed six 10-s sprints and, on a separate occasion, repeated barbell squats to approximately equal the amount of work performed during the sprints. Blood lactate, heart rate, and perceived exertion was measured before and following each exercise bout. Muscle soreness, muscle force, and creatine kinase activity was determined preexercise and through 48 h of recovery. Desmin cytoskeletal protein was determined via muscle biopsy of the vastus lateralis before and at 24 h following each exercise. Plasma protein carbonyls (PC) and malondialdehyde (MDA) were measured as biomarkers of oxidative stress. Heart rate and perceived exertion was not different between exercise sessions (P > 0.05), although lactate was higher following sprinting compared with squatting (P = 0.002). Muscle soreness was greater for squatting than sprinting (P = 0.003) and reached a peak immediately postexercise for both sessions (P = 0.0003). Muscle force was unaffected by either exercise session (P > 0.05), and creatine kinase activity was elevated to a similar extent following both sessions. Desmin-negative fibers were virtually nonexistent after either exercise bout, indicating no loss of this cytoskeletal protein. Neither PC nor MDA was affected by the exercise (P > 0.05). These results suggest that in anaerobically trained men, the oxidative stress and muscle injury response to similarly matched anaerobic exercise bouts is minimal, and not different between exercise modes. Furthermore, when compared with previous literature on untrained subjects, the response is significantly attenuated, possibly because of adaptations occurring as a result of chronic, strenuous anaerobic training.

Combined effects of mild-to-moderate obesity and asthma on physiological and sensory responses to exercise.

PubMed

Cortés-Télles, Arturo; Torre-Bouscoulet, Luis; Silva-Cerón, Monica; Mejía-Alfaro, Roberto; Syed, Nafeez; Zavorsky, Gerald S; Guenette, Jordan A

2015-11-01

Despite the close link between asthma and obesity, there are no studies that have evaluated the sensory and physiological responses to exercise in obese asthmatics. We recently demonstrated that normal weight asthmatics with well controlled disease have preserved cardiorespiratory and sensory responses to exercise relative to non-asthmatic controls. However, these similarities may not hold true in patients with combined obesity and asthma. Accordingly, we sought to determine if combined asthma and obesity was associated with deleterious effects on cardiorespiratory fitness, exercise performance, dyspnoea, and physiological responses to exercise. Fourteen well-controlled obese asthmatics and fourteen age-matched normal weight asthmatics performed routine spirometry and underwent an incremental cardiopulmonary cycle test to assess the ventilatory, pulmonary gas exchange, cardiovascular, and sensory responses to exercise. Groups were well matched for age, height, spirometry, and asthma control. Obese asthmatics had a significantly greater body mass index (33 ± 3 vs. 23 ± 1 kg/m(2), p < 0.001) and lower self-reported activity levels by 47 % relative to normal weight asthmatics (p < 0.05). Obese asthmatics had a significantly lower maximal oxygen uptake (VO(2)) (82 ± 14 vs. 92 ± 10 %predicted) and work rate (75 ± 8 vs. 89 ± 13 %predicted) relative to normal weight asthmatics (p < 0.05). The anaerobic threshold occurred at a lower VO(2) in obese asthmatics vs. normal weight asthmatics (54 ± 15 vs. 66 ± 16 %predicted, p < 0.05). Ventilatory responses were superimposed throughout exercise with no evidence of a ventilatory limitation in either group. Cardiovascular responses were normal in both groups. Dyspnoea responses were similar but the obese asthmatics experienced greater leg fatigue ratings at submaximal work rates. In conclusion, obese individuals with well controlled asthma have reduced cardiorespiratory fitness and greater leg fatigue ratings relative to normal weight asthmatics. The relatively reduced cardiorespiratory fitness and exercise performance in obese compared to normal weight asthmatics is most likely driven by their more sedentary lifestyle and resultant deconditioning rather than due to respiratory factors. Copyright © 2015 Elsevier Ltd. All rights reserved.

Validity of a heart rate monitor during work in the laboratory and on the Space Shuttle

NASA Technical Reports Server (NTRS)

Moore, A. D. Jr; Lee, S. M.; Greenisen, M. C.; Bishop, P.

1997-01-01

Accurate heart rate measurement during work is required for many industrial hygiene and ergonomics situations. The purpose of this investigation was to determine the validity of heart rate measurements obtained by a simple, lightweight, commercially available wrist-worn heart rate monitor (HRM) during work (cycle exercise) sessions conducted in the laboratory and also during the particularly challenging work environment of space flight. Three different comparisons were made. The first compared HRM data to simultaneous electrocardiogram (ECG) recordings of varying heart rates that were generated by an ECG simulator. The second compared HRM data to ECG recordings collected during work sessions of 14 subjects in the laboratory. Finally, ECG downlink and HRM data were compared in four astronauts who performed cycle exercise during space flight. The data were analyzed using regression techniques. The results were that the HRM recorded virtually identical heart rates compared with ECG recordings for the data set generated by an ECG simulator. The regression equation for the relationship between ECG versus HRM heart rate data during work in the laboratory was: ECG HR = 0.99 x (HRM) + 0.82 (r2 = 0.99). Finally, the agreement between ECG downlink data and HRM data during space flight was also very high, with the regression equation being: Downlink ECG HR = 1.05 x (HRM) -5.71 (r2 = 0.99). The results of this study indicate that the HRM provides accurate data and may be used to reliably obtain valid data regarding heart rate responses during work.

How much work is expended for respiration?

PubMed

Johnson, A T

1993-01-01

The rate of work expended to move air in the respiratory system has been determined for five different airflow waveshapes, a non-linear respiratory model and five exercise levels. As expected, the rectangular waveshape was the most efficient. Model conditions were then changed one a time: (i) starting lung volume was allowed to vary, (ii) exhalation flow limitation was added, (iii) respiration was considered to be a metabolic burden determining part of the ventilation requirement and (iv) a respirator mask was added. Although there is no direct work advantage to varying initial lung volume, such volume changes appear to be dictated by the asymmetry of lung recoil pressure about the lung relaxation volume; allowing the work of respiration to become a metabolic burden clearly shows why respiratory waveforms change from rest to exercise; and, adding a respirator imposes a severe respiratory burden on the wearer engaging in moderate, heavy and very heavy exercise.

Effects of a helium/oxygen mixture on individuals' lung function and metabolic cost during submaximal exercise for participants with obstructive lung diseases.

PubMed

Häussermann, Sabine; Schulze, Anja; Katz, Ira M; Martin, Andrew R; Herpich, Christiane; Hunger, Theresa; Texereau, Joëlle

2015-01-01

Helium/oxygen therapies have been studied as a means to reduce the symptoms of obstructive lung diseases with inconclusive results in clinical trials. To better understand this variability in results, an exploratory physiological study was performed comparing the effects of helium/oxygen mixture (78%/22%) to that of medical air. The gas mixtures were administered to healthy, asthmatic, and chronic obstructive pulmonary disease (COPD) participants, both moderate and severe (6 participants in each disease group, a total of 30); at rest and during submaximal cycling exercise with equivalent work rates. Measurements of ventilatory parameters, forced spirometry, and ergospirometry were obtained. There was no statistical difference in ventilatory and cardiac responses to breathing helium/oxygen during submaximal exercise. For asthmatics, but not for the COPD participants, there was a statistically significant benefit in reduced metabolic cost, determined through measurement of oxygen uptake, for the same exercise work rate. However, the individual data show that there were a mixture of responders and nonresponders to helium/oxygen in all of the groups. The inconsistent response to helium/oxygen between individuals is perhaps the key drawback to the more effective and widespread use of helium/oxygen to increase exercise capacity and for other therapeutic applications.

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

PubMed Central

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

2013-01-01

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

The role of exercise and gender for physical self-perceptions and importance ratings in Swedish university students.

PubMed

Lindwall, Magnus; Hassmén, Peter

2004-12-01

The purpose of this study was to investigate how scores on the Physical Self-Perception Profile (PSPP), including scores on the Perceived Importance Profile (PIP), were related to self-reported exercise frequency, duration, and gender in sample of Swedish university students. A total of 164 participants completed the PSPP, PIP, and a questionnaire focusing on frequency and duration of exercise. Exercise frequency, duration, and gender predicted best the PSPP sub-domains of Sport Competence and Physical Conditioning. Exercising more frequently, and for a longer time on each occasion was associated with higher PSPP and PIP scores. Women generally displayed lower PSPP scores than men. These results suggest that exercise professionals need to master a range of appropriate exercise strategies, since doubts concerning self-presentation may work against establishing a regular exercise routine.

Haemoglobin saturation during incremental arm and leg exercise.

PubMed Central

Powers, S. K.; Dodd, S.; Woodyard, J.; Beadle, R. E.; Church, G.

1984-01-01

There are few reports concerning the alterations in the percent of haemoglobin saturated with oxygen (%SO2) during non-steady state incremental exercise. Further, no data exist to describe the %SO2 changes during arm exercise. Therefore, the purpose of this study was made to assess the dynamic changes in %SO2 during incremental arm and leg work. Nine trained subjects (7 males and 2 females) performed incremental arm and leg exercise to exhaustion on an arm crank ergometer and a cycle ergometer, respectively. Ventilation and gas exchange measurements were obtained minute by minute via open circuit spirometry and changes in %SO2 were recorded via an ear oximeter. No significant difference (p greater than 0.05) existed between arm and leg work in end-tidal oxygen (PETO2), end-tidal carbon dioxide (PETCO2), or %SO2 when compared as a function of percent VO2 max. These results provide evidence that arterial O2 desaturation occurs in a similar fashion in both incremental arm and leg work with the greatest changes in %SO2 occurring at work rates greater than 70% VO2 max. PMID:6435715

Cardiovascular and Muscular Consequences of Work-Matched Interval-Type of Concentric and Eccentric Pedaling Exercise on a Soft Robot.

PubMed

Flück, Martin; Bosshard, Rebekka; Lungarella, Max

2017-01-01

Eccentric types of endurance exercise are an acknowledged alternative to conventional concentric types of exercise rehabilitation for the cardiac patient, because they reduce cardiorespiratory strain due to a lower metabolic cost of producing an equivalent mechanical output. The former contention has not been tested in a power- and work-matched situation of interval-type exercise under identical conditions because concentric and eccentric types of exercise pose specific demands on the exercise machinery, which are not fulfilled in current practice. Here we tested cardiovascular and muscular consequences of work-matched interval-type of leg exercise (target workload of 15 sets of 1-min bipedal cycles of knee extension and flexion at 30 rpm with 17% of maximal concentric power) on a soft robotic device in healthy subjects by concomitantly monitoring respiration, blood glucose and lactate, and power during exercise and recovery. We hypothesized that interval-type of eccentric exercise lowers strain on glucose-related aerobic metabolism compared to work-matched concentric exercise, and reduces cardiorespiratory strain to levels being acceptable for the cardiac patient. Eight physically active male subjects (24.0 years, 74.7 kg, 3.4 L O2 min -1 ), which power and endurance performance was extensively characterized, completed the study, finalizing 12 sets on average. Average performance was similar during concentric and eccentric exercise ( p = 0.75) but lower than during constant load endurance exercise on a cycle ergometer at 75% of peak aerobic power output (126 vs. 188 Watt) that is recommended for improving endurance capacity. Peak oxygen uptake (-17%), peak ventilation (-23%), peak cardiac output (-16%), and blood lactate (-37%) during soft robotic exercise were lower during eccentric than concentric exercise. Glucose was 8% increased after eccentric exercise when peak RER was 12% lower than during concentric exercise. Muscle power and RFD were similarly reduced after eccentric and concentric exercise. The results highlight that the deployed interval-type of eccentric leg exercise reduces metabolic strain of the cardiovasculature and muscle compared to concentric exercise, to recommended levels for cardio-rehabilitation (i.e., 50-70% of peak heart rate). Increases in blood glucose concentration indicate that resistance to contraction-induced glucose uptake after the deployed eccentric protocol is unrelated to muscle fatigue.

Cardiovascular and Muscular Consequences of Work-Matched Interval-Type of Concentric and Eccentric Pedaling Exercise on a Soft Robot

PubMed Central

Flück, Martin; Bosshard, Rebekka; Lungarella, Max

2017-01-01

Eccentric types of endurance exercise are an acknowledged alternative to conventional concentric types of exercise rehabilitation for the cardiac patient, because they reduce cardiorespiratory strain due to a lower metabolic cost of producing an equivalent mechanical output. The former contention has not been tested in a power- and work-matched situation of interval-type exercise under identical conditions because concentric and eccentric types of exercise pose specific demands on the exercise machinery, which are not fulfilled in current practice. Here we tested cardiovascular and muscular consequences of work-matched interval-type of leg exercise (target workload of 15 sets of 1-min bipedal cycles of knee extension and flexion at 30 rpm with 17% of maximal concentric power) on a soft robotic device in healthy subjects by concomitantly monitoring respiration, blood glucose and lactate, and power during exercise and recovery. We hypothesized that interval-type of eccentric exercise lowers strain on glucose-related aerobic metabolism compared to work-matched concentric exercise, and reduces cardiorespiratory strain to levels being acceptable for the cardiac patient. Eight physically active male subjects (24.0 years, 74.7 kg, 3.4 L O2 min−1), which power and endurance performance was extensively characterized, completed the study, finalizing 12 sets on average. Average performance was similar during concentric and eccentric exercise (p = 0.75) but lower than during constant load endurance exercise on a cycle ergometer at 75% of peak aerobic power output (126 vs. 188 Watt) that is recommended for improving endurance capacity. Peak oxygen uptake (−17%), peak ventilation (−23%), peak cardiac output (−16%), and blood lactate (−37%) during soft robotic exercise were lower during eccentric than concentric exercise. Glucose was 8% increased after eccentric exercise when peak RER was 12% lower than during concentric exercise. Muscle power and RFD were similarly reduced after eccentric and concentric exercise. The results highlight that the deployed interval-type of eccentric leg exercise reduces metabolic strain of the cardiovasculature and muscle compared to concentric exercise, to recommended levels for cardio-rehabilitation (i.e., 50–70% of peak heart rate). Increases in blood glucose concentration indicate that resistance to contraction-induced glucose uptake after the deployed eccentric protocol is unrelated to muscle fatigue. PMID:28912726

Hypothalamic, rectal, and muscle temperatures in exercising dogs - Effect of cooling

NASA Technical Reports Server (NTRS)

Kruk, B.; Kaciuba-Uscilko, H.; Nazar, K.; Greenleaf, J. E.; Kozlowski, S.

1985-01-01

An experimental investigation of the mechanisms of performance prolongation during exercise is presented. Measurements were obtained of the rectal, muscle, and hypothalamic temperature of dogs during treadmill exercise at an ambient temperature of 22 + or - 1 C, with and without cooling by use of ice packs. In comparison with exercise without cooling, exercise with cooling was found to: (1) increase exercise duration from 90 + or - 14 to 145 + or - 15 min; (2) attenuate increases in hypothalamic, rectal and muscle temperature; (3) decrease respiratory and heart rates; and (4) lower blood lactic acid content. It is shown that although significant differences were found between the brain, core, and muscle temperatures during exercise with and without cooling, an inverse relation was observed between muscle temperature and the total duration of exercise. It is suggested that sustained muscle hyperthermia may have contributed to the limitation of working ability in exercise with and without cooling.

Fluid-electrolyte shifts and thermoregulation - Rest and work in heat with head cooling

NASA Technical Reports Server (NTRS)

Greenleaf, J. E.; Van Beaumont, W.; Brock, P. J.; Montgomery, L. D.; Morse, J. T.; Shvartz, E.; Kravik, S.

1980-01-01

The effects of head cooling on thermoregulation and associated plasma fluid and electrolyte shifts during rest and submaximal exercise in the heat are investigated. Thermoregulatory responses and plasma volume were measured in four male subjects fitted with liquid-cooled neoprene headgear during 60 min of rest, 60 min of ergometer exercise at 45% maximal oxygen uptake and 30 min of recovery in the supine position at 40.1 C and 40% relative humidity. It is found that, compared to control responses, head cooling decreased thigh sweating and increased mean skin temperature at rest and attenuated increases in thigh sweating, heart rate, rectal temperature and ventilation during exercise. During recovery, cooling is observed to facilitate decreases in sweat rate, heart rate, rectal temperature and forearm blood flow and enhance the increase in average temperature. Cooling had no effect on plasma protein, osmotic or electrolyte shifts, and decreased plasma volume losses. The findings indicate the effectiveness of moderate head cooling for the improvement of human performance during exercise in heat.

Exercise-induced quadriceps muscle fatigue in men and women: effects of arterial oxygen content and respiratory muscle work.

PubMed

Dominelli, Paolo B; Molgat-Seon, Yannick; Griesdale, Donald E G; Peters, Carli M; Blouin, Jean-Sébastien; Sekhon, Mypinder; Dominelli, Giulio S; Henderson, William R; Foster, Glen E; Romer, Lee M; Koehle, Michael S; Sheel, A William

2017-08-01

High work of breathing and exercise-induced arterial hypoxaemia (EIAH) can decrease O 2 delivery and exacerbate exercise-induced quadriceps fatigue in healthy men. Women have a higher work of breathing during exercise, dedicate a greater fraction of whole-body V̇O2 towards their respiratory muscles and develop EIAH. Despite a greater reduction in men's work of breathing, the attenuation of quadriceps fatigue was similar between the sexes. The degree of EIAH was similar between sexes, and regardless of sex, those who developed the greatest hypoxaemia during exercise demonstrated the most attenuation of quadriceps fatigue. Based on our previous finding that women have a greater relative oxygen cost of breathing, women appear to be especially susceptible to work of breathing-related changes in quadriceps muscle fatigue. Reducing the work of breathing or eliminating exercise-induced arterial hypoxaemia (EIAH) during exercise decreases the severity of quadriceps fatigue in men. Women have a greater work of breathing during exercise, dedicate a greater fraction of whole-body V̇O2 towards their respiratory muscles, and demonstrate EIAH, suggesting women may be especially susceptible to quadriceps fatigue. Healthy subjects (8 male, 8 female) completed three constant load exercise tests over 4 days. During the first (control) test, subjects exercised at ∼85% of maximum while arterial blood gases and work of breathing were assessed. Subsequent constant load exercise tests were iso-time and iso-work rate, but with EIAH prevented by inspiring hyperoxic gas or work of breathing reduced via a proportional assist ventilator (PAV). Quadriceps fatigue was assessed by measuring force in response to femoral nerve stimulation. For both sexes, quadriceps force was equally reduced after the control trial (-27 ± 2% baseline) and was attenuated with hyperoxia and PAV (-18 ± 1 and -17 ± 2% baseline, P < 0.01, respectively), with no sex difference. EIAH was similar between the sexes, and regardless of sex, subjects with the lowest oxyhaemoglobin saturation during the control test had the greatest quadriceps fatigue attenuation with hyperoxia (r 2  = 0.79, P < 0.0001). For the PAV trial, despite reducing the work of breathing to a greater degree in men (men: 60 ± 5, women: 75 ± 6% control, P < 0.05), the attenuation of quadriceps fatigue was similar between the sexes (36 ± 4 vs. 37 ± 7%). Owing to a greater relative V̇O2 of the respiratory muscles in women, less of a change in work of breathing is needed to reduce quadriceps fatigue. © 2017 The Authors. The Journal of Physiology © 2017 The Physiological Society.

Pedaling rate is an important determinant of human oxygen uptake during exercise on the cycle ergometer.

PubMed

Formenti, Federico; Minetti, Alberto E; Borrani, Fabio

2015-09-01

Estimation of human oxygen uptake (V˙o2) during exercise is often used as an alternative when its direct measurement is not feasible. The American College of Sports Medicine (ACSM) suggests estimating human V˙o2 during exercise on a cycle ergometer through an equation that considers individual's body mass and external work rate, but not pedaling rate (PR). We hypothesized that including PR in the ACSM equation would improve its V˙o2 prediction accuracy. Ten healthy male participants' (age 19-48 years) were recruited and their steady-state V˙o2 was recorded on a cycle ergometer for 16 combinations of external work rates (0, 50, 100, and 150 W) and PR (50, 70, 90, and 110 revolutions per minute). V˙o2 was calculated by means of a new equation, and by the ACSM equation for comparison. Kinematic data were collected by means of an infrared 3-D motion analysis system in order to explore the mechanical determinants of V˙o2. Including PR in the ACSM equation improved the accuracy for prediction of sub-maximal V˙o2 during exercise (mean bias 1.9 vs. 3.3 mL O2 kg(-1) min(-1)) but it did not affect the accuracy for prediction of maximal V˙o2 (P > 0.05). Confirming the validity of this new equation, the results were replicated for data reported in the literature in 51 participants. We conclude that PR is an important determinant of human V˙o2 during cycling exercise, and it should be considered when predicting oxygen consumption. © 2015 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.

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.

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

PubMed

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

2016-10-14

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

The Effects of Exercising in Different Natural Environments on Psycho-Physiological Outcomes in Post-Menopausal Women: A Simulation Study.

PubMed

White, Mathew P; Pahl, Sabine; Ashbullby, Katherine J; Burton, Francesca; Depledge, Michael H

2015-09-23

The current study examined potential psycho-physiological benefits from exercising in simulated natural environments among a sample of post-menopausal women using a laboratory based protocol. Participants cycled on a stationary exercise bike for 15 min while facing either a blank wall (Control) or while watching one of three videos: Urban (Grey), Countryside (Green), Coast (Blue). Blood pressure, heart rate and affective responses were measured pre-post. Heart rate, affect, perceived exertion and time perception were also measured at 5, 10 and 15 min during exercise. Experience evaluation was measured at the end. Replicating most earlier findings, affective, but not physiological, outcomes were more positive for exercise in the simulated Green and, for the first time, Blue environment, compared to Control. Moreover, only the simulated Blue environment was associated with shorter perceived exercise duration than Control and participants were most willing to repeat exercise in the Blue setting. The current research extended earlier work by exploring the effects of "blue exercise" and by using a demographic with relatively low average levels of physical activity. That this sample of postmenopausal women were most willing to repeat a bout of exercise in a simulated Blue environment may be important for physical activity promotion in this cohort.

Revisiting the relationship between exercise heart rate and music tempo preference.

PubMed

Karageorghis, Costas I; Jones, Leighton; Priest, David-Lee; Akers, Rose I; Clarke, Adam; Perry, Jennifer M; Reddick, Benjamin T; Bishop, Daniel T; Lim, Harry B T

2011-06-01

In the present study, we investigated a hypothesized quartic relationship (meaning three inflection points) between exercise heart rate (HR) and preferred music tempo. Initial theoretical predictions suggested a positive linear relationship (Iwanaga, 1995a, 1995b); however, recent experimental work has shown that as exercise HR increases, step changes and plateaus that punctuate the profile of music tempo preference may occur (Karageorghis, Jones, & Stuart, 2008). Tempi bands consisted of slow (95-100 bpm), medium (115-120 bpm), fast (135-140 bpm), and very fast (155-160 bpm) music. Twenty-eight active undergraduate students cycled at exercise intensities representing 40, 50, 60, 70, 80, and 90% of their maximal HR reserve while their music preference was assessed using a 10-point scale. The Exercise Intensity x Music Tempo interaction was significant, F(6.16, 160.05) = 7.08, p < .001, 7,2 = .21, as was the test for both cubic and quartic trajectories in the exercise HR-preferred-music-tempo relationship (p < .001). Whereas slow tempo music was not preferred at any exercise intensity, preference for fast tempo increased, relative to medium and very fast tempo music, as exercise intensity increased. The implications for the prescription of music in exercise and physical activity contexts are discussed.

Immediate Effects of Smoking on Cardiorespiratory Responses During Dynamic Exercise: Arm Vs. Leg Ergometry.

PubMed

Chen, Chien-Liang; Tang, Jing-Shia; Li, Ping-Chia; Chou, Pi-Ling

2015-01-01

This study compared the immediate effects of smoking on cardiorespiratory responses to dynamic arm and leg exercises. This randomized crossover study recruited 14 college students. Each participant underwent two sets of arm-cranking (AC) and leg-cycling (LC) exercise tests. The testing sequences of the control trial (participants refrained from smoking for 8 h before testing) and the experimental trial (participants smoked two cigarettes immediately before testing) were randomly chosen. We observed immediate changes in pulmonary function and heart rate variability after smoking and before the exercise test. The participants then underwent graded exercise tests of their arms and legs until reaching exhaustion. We compared the peak work achieved and time to exhaustion during the exercise tests with various cardiorespiratory indices [i.e., heart rate, oxygen consumption (VO2), minute ventilation (VE)]. The differences between the smoking and control trials were calculated using paired t-tests. For the exercise test periods, VO2, heart rate, and VE values were calculated at every 10% increment of the maximal effort time. The main effects of the time and trial, as well as their trial-by-time (4 × 10) interaction effects on the outcome measures, were investigated using repeated measure ANOVA with trend analysis. 5 min after smoking, the participants exhibited reduced forced vital capacities and forced expiratory volumes in the first second (P < 0.05), in addition to elevated resting heart rates (P < 0.001). The high-frequency, low-frequency, and the total power of the heart rate variability were also reduced (P < 0.05) at rest. For the exercise test periods, smoking reduced the time to exhaustion (P = 0.005) and the ventilatory threshold (P < 0.05) in the LC tests, whereas no significant effects were observed in the AC tests. A trend analysis revealed a significant trial-by-time interaction effect for heart rate, VO2, and VE during the graded exercise test (all P < 0.001). Lower VO2 and VE levels were exhibited in the exercise response of the smoking trial than in those of the control LC trials, whereas no discernable inter-trial difference was observed in the AC trials. Moreover, the differences in heart rate and VE response between the LC and AC exercises were significantly smaller after the participants smoked. This study verified that smoking significantly decreased performance and cardiorespiratory responses to leg exercises. However, the negative effects of smoking on arm exercise performance were not as pronounced.

Speckle Tracking Imaging in Normal Stress Echocardiography.

PubMed

Leitman, Marina; Tyomkin, Vladimir; Peleg, Eli; Zyssman, Izhak; Rosenblatt, Simcha; Sucher, Edgar; Gercenshtein, Vered; Vered, Zvi

2017-04-01

Exercise stress echocardiography is a widely used modality for the diagnosis and follow-up of patients with coronary artery disease. During the last decade, speckle tracking imaging has been used increasingly for accurate evaluation of cardiac function. This work aimed to assess speckle-tracking imaging parameters during nonischemic exercise stress echocardiography. During 2011 to 2014 we studied 46 patients without history of coronary artery disease, who completed exercise stress echocardiography protocol, had normal left ventricular function, a nonischemic response, and satisfactory image quality. These exams were analyzed with speckle-tracking imaging software at rest and at peak exercise. Peak strain and time-to-peak strain were measured at rest and after exercise. Clinical follow-up included a telephone contact 1 to 3 years after stress echo exam, confirming freedom from coronary events during this time. Global and regional peak strain increased following exercise. Time-to-peak global and regional strain and time-to-peak strain adjusted to the heart rate were significantly shorter in all segments after exercise. Rest-to-stress ratio of time-to-peak strain adjusted to the heart rate was 2.0 to 2.8. Global and regional peak strain rise during normal exercise echocardiography. Peak global and regional strain occur before or shortly after aortic valve closure at rest and after exercise, and the delay is more apparent at the basal segments. Time-to-peak strain normally shortens significantly during exercise; after adjustment to heart rate it shortens by a ratio of 2.0 to 2.8. These data may be useful for interpretation of future exercise stress speckle-tracking echocardiography studies. © 2016 by the American Institute of Ultrasound in Medicine.

Absolute hypoxic exercise training enhances in vitro thrombin generation by increasing procoagulant platelet-derived microparticles under high shear stress in sedentary men.

PubMed

Chen, Yu-Wen; Chen, Yi-Ching; Wang, Jong-Shyan

2013-05-01

HS (high shear) stress associated with artery stenosis facilitates TG (thrombin generation) by increasing the release of procoagulant PDMPs (platelet-derived microparticles). Physical exercise and hypoxia may paradoxically modulate vascular thrombotic risks. The aim of the present study was to investigate how exercise training with/without hypoxia affected TG mediated by PDMPs under physio-pathological shear flows. A total of 75 sedentary males were randomly divided into five groups (n=15 in each group): 21% O2 [NC (normoxic control)] or 15% O2 [HC (hypoxic control)] at rest or were trained at 50% of peak work rate under 21% O2 [NT (normoxic training)] or 15% O2 [HAT (hypoxic-absolute training)], or 50% of HR (heart rate) reserve under 15% O2 [HRT (hypoxic-relative training)] for 30 min/day, 5 days/week for 4 weeks. The PDMP characteristics and dynamic TG were measured by flow cytometry and thrombinography respectively. Before the intervention, strenuous exercise markedly increased the PDMP count (14.8%) and TG rate (19.5%) in PDMP-rich plasma at 100 dynes/cm2 of shear stress (P<0.05). After the interventions, both NT and HRT significantly attenuated the enhancement of HS-induced PDMPs (4.7 and 4.9%) and TG rate (3.8 and 3.0%) (P<0.05) by severe exercise. Conversely, HAT notably promoted the PDMP count (37.3%) and TG rate (38.9%) induced by HS (P<0.05), concurrent with increasing plasma TF (tissue factor) and coagulation factor V levels at rest or following exercise. We conclude that both HRT and NT depress similarly HS-mediated TG during exercise, but HAT accelerates the prothrombotic response to vigorous exercise. These findings provide new insights into how exercise training under a hypoxic condition influences the risk of thrombosis associated with stenotic arteries.

Endurance Performance during Severe-Intensity Intermittent Cycling: Effect of Exercise Duration and Recovery Type.

PubMed

Barbosa, Luis F; Denadai, Benedito S; Greco, Camila C

2016-01-01

Slow component of oxygen uptake (VO 2 SC) kinetics and maximal oxygen uptake (VO 2 max) attainment seem to influence endurance performance during constant-work rate exercise (CWR) performed within the severe intensity domain. In this study, it was hypothesized that delaying the attainment of VO 2 max by reducing the rates at which VO 2 increases with time (VO 2 SC kinetics) would improve the endurance performance during severe-intensity intermittent exercise performed with different work:recovery duration and recovery type in active individuals. After the estimation of the parameters of the VO 2 SC kinetics during CWR exercise, 18 males were divided into two groups (Passive and Active recovery) and performed at different days, two intermittent exercises to exhaustion (at 95% IVO 2 max, with work: recovery ratio of 2:1) with the duration of the repetitions calculated from the onset of the exercise to the beginning of the VO 2 SC (Short) or to the half duration of the VO 2 SC (Long). The active recovery was performed at 50% IVO 2 max. The endurance performance during intermittent exercises for the Passive (Short = 1523 ± 411; Long = 984 ± 260 s) and Active (Short = 902 ± 239; Long = 886 ± 254 s) groups was improved compared with CWR condition (Passive = 540 ± 116; Active = 489 ± 84 s). For Passive group, the endurance performance was significantly higher for Short than Long condition. However, no significant difference between Short and Long conditions was found for Active group. Additionally, the endurance performance during Short condition was higher for Passive than Active group. The VO 2 SC kinetics was significantly increased for CWR (Passive = 0.16 ± 0.04; Active = 0.16 ± 0.04 L.min -2 ) compared with Short (Passive = 0.01 ± 0.01; Active = 0.03 ± 0.04 L.min -2 ) and Long (Passive = 0.02 ± 0.01; Active = 0.01 ± 0.01 L.min -2 ) intermittent exercise conditions. No significant difference was found among the intermittent exercises. It can be concluded that the endurance performance is negatively influenced by active recovery only during shorter high-intensity intermittent exercise. Moreover, the improvement in endurance performance seems not be explained by differences in the VO 2 SC kinetics, since its values were similar among all intermittent exercise conditions.

A randomised control trial of physical activity in a perceived environment on self-esteem and mood in UK adolescents.

PubMed

Wood, Carly; Angus, Caroline; Pretty, Jules; Sandercock, Gavin; Barton, Jo

2013-01-01

This study assessed whether exercising whilst viewing natural or built scenes affected self-esteem (SE) and mood in adolescents. Twenty-five adolescents participated in three exercise tests on consecutive days. A graded exercise test established the work rate equivalent to 50% heart rate reserve for use in subsequent constant load tests (CLTs). Participants undertook two 15-min CLTs in random order viewing scenes of either natural or built environments. Participants completed Rosenberg's SE scale and the adolescent profile of mood states questionnaire pre- and post-exercise. There was a significant main effect for SE (F(1) = 6.10; P < 0.05) and mood (F(6) = 5.29; P < 0.001) due to exercise, but no effect of viewing different environmental scenes (P > 0.05). Short bouts of moderate physical activity can have a positive impact on SE and mood in adolescents. Future research should incorporate field studies to examine the psychological effects of contact with real environments.

Effects of cigarette smoking on cardiac autonomic function during dynamic exercise.

PubMed

Mendonca, Goncalo V; Pereira, Fernando D; Fernhall, Bo

2011-06-01

The purpose of this study was to investigate the acute effect of cigarette smoking on cardiac autonomic function in young adult smokers during dynamic exercise. Fourteen healthy young smokers (21.4 ± 3.4 years) performed peak and submaximal exercise protocols under control and smoking conditions. Resting and submaximal beat-to-beat R-R series were recorded and spectrally decomposed using the fast Fourier transformation. Smoking resulted in a significant decrease in work time, VO(2peak) and peak O(2) pulse (P < 0.05). Heart rate increased at rest and during submaximal exercise after smoking (P < 0.05). The raw high frequency and low frequency power were significantly reduced by smoking, both at rest and during exercise (P < 0.05). The low to high frequency ratio was higher after smoking (P < 0.05). The normalised low frequency power was also significantly increased by smoking, but only at rest (P < 0.05). These data demonstrate that the tachycardic effect elicited by smoking is accompanied by acute changes in heart rate spectral components both at rest and during exercise. Therefore, the cardiac autonomic control is altered by smoking not only at rest, but also during exercise, resulting in reduced vagal modulation and increased sympathetic dominance.

Cardiac autonomic response following high-intensity running work-to-rest interval manipulation.

PubMed

Cipryan, Lukas; Laursen, Paul B; Plews, Daniel J

2016-10-01

The cardiorespiratory, cardiac autonomic (via heart rate variability (HRV)) and plasma volume responses to varying sequences of high-intensity interval training (HIT) of consistent external work were investigated. Twelve moderately trained males underwent three HIT bouts and one control session. The HIT trials consisted of warm-up, followed by 12 min of 15 s, 30 s or 60 s work:relief HIT sequences at an exercise intensity of 100% of the individual velocity at [Formula: see text]O2max (v[Formula: see text]O2max), interspersed by relief intervals at 60% [Formula: see text]O2max (work/relief ratio = 1). HRV was evaluated via the square root of the mean sum of the squared differences between R-R intervals (rMSSD) before, 1 h, 3 h and 24 h after the exercise. Plasma volume was assessed before, immediately after, and 3 h and 24 h after. There were no substantial between-trial differences in acute cardiorespiratory responses. The rMSSD values remained decreased 1 h after the exercise cessation in all exercise groups. The rMSSD subsequently increased between 1 h and 3 h after exercise, with the most pronounced change in the 15/15 group. There were no relationships between HRV and plasma volume. All HIT protocols resulted in similar cardiorespiratory responses with slightly varying post-exercise HRV responses, with the 30/30 protocol eliciting the least disruption to post-exercise HRV. These post-exercise HRV findings suggest that the 30/30 sequence may be the preferable HIT prescription when the between-training period is limited.

Potential benefits of maximal exercise just prior to return from weightlessness

NASA Technical Reports Server (NTRS)

Convertino, Victor A.

1987-01-01

The purpose of this study was to determine whether performance of a single maximal bout of exercise during weightlessness within hours of return to earth would enhance recovery of aerobic fitness and physical work capacities under a 1G environment. Ten healthy men were subjected to a 10-d bedrest period in the 6-deg headdown position. A graded maximal supine cycle ergometer test was performed before and at the end of bedrest to simulate exercise during weightlessness. Following 3 h of resumption of the upright posture, a second maximal exercise test was performed on a treadmill to measure work capacity under conditions of 1G. Compared to before bedrest, peak oxygen consumption, V(O2), decreased by 8.7 percent and peak heart rate (HR) increased by 5.6 percent in the supine cycle test at the end of bedrest. However, there were no significant changes in peak V(O2) and peak HR in the upright treadmill test following bedrest. These data suggest that one bout of maximal leg exercise prior to return from 10 d of weightlessness may be adequate to restore preflight aerobic fitness and physical work capacity.

Effect of an aerobic exercise intervention on cardiac autonomic regulation: A worksite RCT among cleaners.

PubMed

Hallman, David M; Holtermann, Andreas; Søgaard, Karen; Krustrup, Peter; Kristiansen, Jesper; Korshøj, Mette

2017-02-01

The aim of this randomized controlled trial (RCT) was to determine whether aerobic exercise during work hours affects cardiac autonomic regulation in cleaners characterized by high levels of occupational physical activity and poor cardiorespiratory fitness. Eligible cleaners (n=116) were randomized to an aerobic exercise group (n=59) or a reference group (n=57) with lectures. The intervention group received two 30-min sessions per week of supervised aerobic exercise over 4months. Diurnal measurements of heart rate variability (HRV) and physical activity (accelerometry) were obtained at baseline and at 4-month follow-up. Time and frequency domain indices of HRV were derived during work, leisure time and sleep to evaluate cardiac autonomic regulation. Linear mixed models were used to determine the effect of the intervention on HRV indices, with adjustment for age, gender and daily use of antihypertensive and/or heart medication. Compared with the reference group, the exercise group increased all HRV indices apart from a reduction in LF/HF ratio from baseline to follow-up both during work (p<0.05) and leisure (p<0.05). In contrast, during sleep, the HRV indices tended to decrease in the exercise group compared with the reference group from baseline to follow-up, being significant for the HF spectral component (p=0.03). Among cleaners, a worksite aerobic exercise intervention improved cardiac autonomic regulation during work and leisure, but not during sleep. The health effect of this contrasting change in autonomic regulation needs further investigation. Copyright © 2016 Elsevier Inc. All rights reserved.

Gender- and hydration- associated differences in the physiological response to spinning.

PubMed

Ramos-Jiménez, Arnulfo; Hernández-Torres, Rosa Patricia; Wall-Medrano, Abraham; Torres-Durán, Patricia Victoria; Juárez-Oropeza, Marco Antonio; Viloria, María; Villalobos-Molina, Rafael

2014-03-01

There is scarce and inconsistent information about gender-related differences in the hydration of sports persons, as well as about the effects of hydration on performance, especially during indoor sports. To determine the physiological differences between genders during in indoor physical exercise, with and without hydration. 21 spinning sportspeople (12 men and 9 women) participated in three controlled, randomly assigned and non-sequential hydration protocols, including no fluid intake and hydration with plain water or a sports drink (volume adjusted to each individual every 15 min), during 90 min of spinning exercise. The response variables included body mass, body temperature, heart rate and blood pressure. During exercise without hydration, men and women lost ~2% of body mass, and showed higher body temperature (~0.2°C), blood pressure (~4 mmHg) and heart rate (~7 beats/min) compared to exercises with hydration. Body temperature and blood pressure were higher for men than for women during exercise without hydration, differences not observed during exercise with hydration. Between 42-99% of variance in body temperature, blood pressure and heart rate could be explained by the physical characteristics of subjects and the work done. During exercise with hydration (either with water or sport drink), the physiological response was similar for both genders. Exercise without hydration produced physical stress, which could be prevented with either of the fluids (plain water was sufficient). Gender differences in the physiological response to spinning (body temperature, mean blood pressure and heart rate) can be explained in part by the distinct physical characteristics of each individual. Copyright AULA MEDICA EDICIONES 2014. Published by AULA MEDICA. All rights reserved.

Fluid-electrolyte shifts and thermoregulation: Rest and work in heat with head cooling.

PubMed

Greenleaf, J E; Van Beaumont, W; Brock, P J; Montgomery, L D; Morse, J T; Shvartz, E; Kravik, S

1980-08-01

Plasma volume and thermoregulatory responses were measured, during head and neck cooling with a liquid-cooled neoprene headgear, in four men (21-43 years old) during 60 min of rest, 60 min of ergometer exercise (45% VO2 max), and 30 min of recovery in the supine position at 40.1 degrees C DBT and 40% rh. Compared with control (noncooling) responses, cooling decreased thigh sweating and increased mean skin temperature (Tsk) at rest, and attenuated the increases in thigh sweating by 0.26 mg/min x cm2 (-22.4%, p < 0.05), heart rate by 10 b/min (-8.5%, N.S.), rectal temperature (Tre) by 0.3 degrees C (N.S.), and ventilation by 12.5% (N.S.) during exercise. In recovery, cooling facilitated the decreases in thigh sweat rate, heart rate, Tre, and forearm blood flow, and enhanced the increase in Tsk toward control levels. Cooling had no effect upon plasma protein, osmotic, or electrolyte shifts during rest, exercise, or recovery. Plasma volume (PV) loss during exercise was 11.2% without cooling and 10.9% with cooling. Cooling increased PV by 3% (p < 0.05) during rest, and this differential was maintained throughout the exercise and recovery periods.

Exercise Holds Immediate Benefits for Affect and Cognition in Younger and Older Adults

PubMed Central

Hogan, Candice L.; Mata, Jutta; Carstensen, Laura L.

2013-01-01

Physical activity is associated with improved affective experience and enhanced cognitive processing. Potential age differences in the degree of benefit, however, are poorly understood because most studies examine either younger or older adults. The present study examined age differences in cognitive performance and affective experience immediately following a single bout of moderate exercise. Participants (144 community members aged 19 to 93) were randomly assigned to one of two experimental conditions: (a) exercise (15 min of moderate intensity stationary cycling) or (b) control (15 min completing ratings of neutral IAPS images). Before and after the manipulation, participants completed tests of working memory and momentary affect experience was measured. Results suggest that exercise is associated with increased levels of high-arousal positive affect (HAP) and decreased levels of low-arousal positive affect (LAP) relative to control condition. Age moderated the effects of exercise on LAP, such that younger age was associated with a drop in reported LAP postexercise, whereas the effects of exercise on HAP were consistent across age. Exercise also led to faster RTs on a working memory task than the control condition across age. Self-reported negative affect was unchanged. Overall, findings suggest that exercise may hold important benefits for both affective experience and cognitive performance regardless of age. PMID:23795769

The rate of phosphocreatine hydrolysis and resynthesis in exercising muscle in humans using 31P-MRS.

PubMed

Yoshida, Takayoshi

2002-09-01

Time-resolved 31-phosphorus nuclear magnetic resonance spectroscopy (31P-MRS) of the biceps femoris muscles was performed during exercise and recovery in six healthy sedentary male subjects (maximal oxygen uptake; 46.6 +/- 1.7 (SEM) ml.kg-1.min-1), 5 male sprinters (56.2 +/- 2.5), and 5 male long-distance runners (73.6 +/- 2.2). Each performed 4 min of knee flexion exercises at absolute values of 1.63 W and 4.90 W, followed by 5 min of recovery in a prone position in a 2.1 T superconducting magnet with a 67 cm bore. 31P-MRS spectra were recorded every 12.8 s during the rest-exercise-recovery sequence. Computer-aided contour analysis and pixel imaging of phosphocreatine peaks (PCr) and inorganic phosphate (Pi) were performed. The work loads in the present study were selected as mild exercise (1.63 W) and heavy exercise (4.90 W), corresponding to 18-23% and 54-70% of maximal exercise intensity. Long-distance runners showed a significantly smaller decrement in PCr and less acidification at a given exercise intensity compared to those shown by sedentary subjects. The transient responses of PCr and Pi during recovery were characterized by first-order kinetics. After exercise, the recovery rates of PCr and Pi were significantly faster in long-distance runners than in sedentary subjects (P < 0.05). Since it is postulated that PCr resynthesis is controlled by aerobic metabolism and mitochondrial creatine kinase, it is suggested that the faster PCr and Pi recovery rates and decreased acidification seen in long-distance runners during and after exercise might be attributed to their greater capacity for aerobic metabolism.

The Effects of Exercising in Different Natural Environments on Psycho-Physiological Outcomes in Post-Menopausal Women: A Simulation Study

PubMed Central

White, Mathew P.; Pahl, Sabine; Ashbullby, Katherine J.; Burton, Francesca; Depledge, Michael H.

2015-01-01

The current study examined potential psycho-physiological benefits from exercising in simulated natural environments among a sample of post-menopausal women using a laboratory based protocol. Participants cycled on a stationary exercise bike for 15 min while facing either a blank wall (Control) or while watching one of three videos: Urban (Grey), Countryside (Green), Coast (Blue). Blood pressure, heart rate and affective responses were measured pre-post. Heart rate, affect, perceived exertion and time perception were also measured at 5, 10 and 15 min during exercise. Experience evaluation was measured at the end. Replicating most earlier findings, affective, but not physiological, outcomes were more positive for exercise in the simulated Green and, for the first time, Blue environment, compared to Control. Moreover, only the simulated Blue environment was associated with shorter perceived exercise duration than Control and participants were most willing to repeat exercise in the Blue setting. The current research extended earlier work by exploring the effects of “blue exercise” and by using a demographic with relatively low average levels of physical activity. That this sample of postmenopausal women were most willing to repeat a bout of exercise in a simulated Blue environment may be important for physical activity promotion in this cohort. PMID:26404351

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

PubMed

Iscoe, K E; Riddell, M C

2011-07-01

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

Common and specific process factors in cardiac rehabilitation: independent and interactive effects of the working alliance and self-efficacy.

PubMed

Burns, John W; Evon, Donna

2007-11-01

Therapeutic processes in cardiac rehabilitation programs are virtually unexamined. Models were tested by which changes in the working alliance between patient and staff (agreement on goals/tasks; emotional bond) may affect outcomes in conjunction with changes in patient self-efficacy to change their diets and increase exercise. Cardiac patients (n = 79) participated in a 12-week program, and completed assessments at early, mid, and late treatment. Changes in cardiac depression, physical health, perceived exertion during exercise, rate/pressure product at submaximal exercise tolerance, weight loss, return to work, total fat intake. Early-treatment changes in agreement on goals/tasks were related to changes in psychosocial factors and perceived exertion during exercise independent of effects of changes in self-efficacy. Early-treatment changes in goals/tasks and self-efficacy interacted to predict changes in cardiorespiratory fitness, weight loss, and return to work such that patients high on both goals/tasks and self-efficacy showed the most gains. Sound therapeutic relationships between patients and staff may play an important role in facilitating the achievement of a wide-range of salutary outcomes during cardiac rehabilitation. (PsycINFO Database Record (c) 2007 APA, all rights reserved).

Ground reaction forces and heart rate profile of aerobic dance instructors during a low and high impact exercise programme.

PubMed

Rousanoglou, E N; Boudolos, K D

2005-06-01

The magnitude of ground reaction forces (GRF) has been associated, although never verified, with the high incidence of lower extremities injuries in aerobic dance (AD) instructors. Moreover, during their working activities AD instructors have demonstrated HR levels, such as 70% HRmax, values, more in training rather in working status. This study was designed to investigate GRF and heart rate (HR) exhibited by AD instructors of both genders, during a simulated AD instruction, from the perspective of accepted occupational workloads. Fourteen females and 14 males instructors performed a 35 min AD exercise programme (warm up--low impact (LI) interval--in high impact (HI) interval--cool down). Four GRF measurements were taken during LI and HI time intervals, respectively. HR was recorded throughout the whole experimental procedure and was synchronised to GRF measurements. All GRF and HR values were significantly increased in HI exercise (p<0.05) with a non significant (p>0.05) time effect for GRF. In both LI and HI exercises, females demonstrated significantly higher vertical but lower lateral GRF (p<0.05) and significantly shorter cycles of movement (p<0.05) while in HI exercise they had significant longer flight times (p<0.05). For both genders, HR was kept at 70% and 80% of HR(max-calc) and RHR was 60% and 70%, during LI and HI intervals respectively, with females showing a trend, though non-significant, for higher HR values. The gender specificity of the significant vertical and lateral GRF pattern differences, may possibly be associated with the significant anthropometric differences of male and female AD instructors. HR(max-calc) and RHR exceeded the accepted occupational levels rising to training status levels. We suggest that AD instructors take up such instructing methods which allow them to minimize the magnitude or the rate of GRF, as well as HR levels, developed in the course of their working hour.

Oxygen Consumption in the First Stages of Strenuous Work as a Function of Prior Exercise.

ERIC Educational Resources Information Center

Gutin, Bernard; And Others

This study examined the extent to which 10 minutes of prior exercise (PE) at a workload adjusted to maintain a heart rate (HR) of 140 beats per minute could facilitate the mobilization of the oxygen transport system in a strenuous criterion task (CT). The control treatment involved completion of the CT following 10 minutes of rest on the…

Effect of cooling during inter-exercise periods on subsequent intramuscular water movement and muscle performance.

PubMed

Yanagisawa, O; Otsuka, S; Fukubayashi, T

2014-02-01

To evaluate the effects of cooling between exercise sessions on intramuscular water movement and muscle performance, the lower extremities of nine untrained men were assigned to either a cooling protocol (20-min water immersion, 15 °C) or a noncooling protocol. Each subject performed two exercise sessions involving maximal concentric knee extension and flexion (three repetitions, 60°/s; followed by 50 repetitions, 180°/s). The peak torque at 60°/s and total work, mean power, and decrease rate of torque value at 180°/s were evaluated. Axial magnetic resonance diffusion-weighted images of the mid-thigh were obtained before and after each exercise session. Apparent diffusion coefficient (ADC) values for the quadriceps and hamstrings were calculated for evaluating intramuscular water movement. Both groups exhibited significantly increased ADC values for the quadriceps and hamstrings after each exercise session. These ADC values returned to the pre-exercise level after water immersion. No significant difference was observed in muscle performance from first exercise session to the next in either group, except for increased total work and mean power in knee flexion in the cooled group. Cooling intervention between exercise sessions decreased exercise-induced elevation of intramuscular water movement and had some beneficial effects on muscle endurance of knee flexors, but not knee extensors. © 2012 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Athletes at altitude

PubMed Central

Pugh, L. G. C. E.

1967-01-01

1. Six international middle-distance runners were investigated during 4 weeks in England and during a similar period in Mexico City (2270 m (7450 ft.)) 2. In 3-mile (4828 m) time trials at 2270 m the increase in time taken by four subjects compared with sea level was 8·5% on the 4th day and 5·7% on the 29th day. There was thus a gain of 2·8% or 20 sec in time associated with acclimatization. 3. In 1-mile (1609 m) time trials the times were increased by 3·6% in the first week at altitude and by 1·5% in the 4th week. The improvement amounted to 2·1%, or 4·9 sec. 4. In 5 min maximum exercise on the ergometer maximum O2 intake for six subjects at altitude was reduced by 14·6% on the 2nd day and 9·5% on the 27th. Only one subject showed no change in maximum oxygen intake (V̇O2, max) with time spent at altitude. 5. Although V̇O2, max was persistently reduced at altitude work rates finally exceeded sea-level values, owing to increased over-all efficiency. 6. Forty-minute recovery O2 intakes after 5 min maximum exercise averaged 17·35 l. at sea level and 17·53 l. at altitude. Mean values from 40th to 50th min were within ± 7% of pre-exercise values. 7. Serial tests at increasing loads yielded a straight-line relation between O2 intake and work rate over a wide range of work rates at sea level and at altitude. Heart rate and ventilation for given work intensity were maximal in the first 2-10 days at altitude and thereafter declined. 8. Capillary HbO2 saturation fell from 93% at rest to 87% in maximum exercise. The corresponding alveolar gas tensions were PA, O2 89 mm Hg, PA, CO2 24 mm Hg. About half the total unsaturation in maximum exercise was explained by the Bohr effect. 9. In six of eight pairs of determinations V̇O2, max measured on the ergometer was within ± 0·15 l./min of V̇O2, max measured on the running track. Nevertheless, it was not possible to predict running performance from ergometer measurements. PMID:6058997

Low-Load High Volume Resistance Exercise Stimulates Muscle Protein Synthesis More Than High-Load Low Volume Resistance Exercise in Young Men

PubMed Central

Burd, Nicholas A.; West, Daniel W. D.; Staples, Aaron W.; Atherton, Philip J.; Baker, Jeff M.; Moore, Daniel R.; Holwerda, Andrew M.; Parise, Gianni; Rennie, Michael J.; Baker, Steven K.; Phillips, Stuart M.

2010-01-01

Background We aimed to determine the effect of resistance exercise intensity (% 1 repetition maximum—1RM) and volume on muscle protein synthesis, anabolic signaling, and myogenic gene expression. Methodology/Principal Findings Fifteen men (21±1 years; BMI = 24.1±0.8 kg/m2) performed 4 sets of unilateral leg extension exercise at different exercise loads and/or volumes: 90% of repetition maximum (1RM) until volitional failure (90FAIL), 30% 1RM work-matched to 90%FAIL (30WM), or 30% 1RM performed until volitional failure (30FAIL). Infusion of [ring-13C6] phenylalanine with biopsies was used to measure rates of mixed (MIX), myofibrillar (MYO), and sarcoplasmic (SARC) protein synthesis at rest, and 4 h and 24 h after exercise. Exercise at 30WM induced a significant increase above rest in MIX (121%) and MYO (87%) protein synthesis at 4 h post-exercise and but at 24 h in the MIX only. The increase in the rate of protein synthesis in MIX and MYO at 4 h post-exercise with 90FAIL and 30FAIL was greater than 30WM, with no difference between these conditions; however, MYO remained elevated (199%) above rest at 24 h only in 30FAIL. There was a significant increase in AktSer473 at 24h in all conditions (P = 0.023) and mTORSer2448 phosphorylation at 4 h post-exercise (P = 0.025). Phosporylation of Erk1/2Tyr202/204, p70S6KThr389, and 4E-BP1Thr37/46 increased significantly (P<0.05) only in the 30FAIL condition at 4 h post-exercise, whereas, 4E-BP1Thr37/46 phosphorylation was greater 24 h after exercise than at rest in both 90FAIL (237%) and 30FAIL (312%) conditions. Pax7 mRNA expression increased at 24 h post-exercise (P = 0.02) regardless of condition. The mRNA expression of MyoD and myogenin were consistently elevated in the 30FAIL condition. Conclusions/Significance These results suggest that low-load high volume resistance exercise is more effective in inducing acute muscle anabolism than high-load low volume or work matched resistance exercise modes. PMID:20711498

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

PubMed

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

2008-08-01

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

The effect of fatigue and training status on firefighter performance.

PubMed

Dennison, Katie J; Mullineaux, David R; Yates, James W; Abel, Mark G

2012-04-01

Firefighting is a strenuous occupation that requires optimal levels of physical fitness. The National Fire Protection Association suggests that firefighters should be allowed to exercise on duty to maintain adequate fitness levels. However, no research has addressed the effect of exercise-induced fatigue on subsequent fire ground performance. Therefore, the primary purpose of this study was to determine the effect that a single exercise session had on the performance of a simulated fire ground test (SFGT). Secondarily, this study sought to compare the effect of physical training status (i.e., trained vs. untrained firefighters) on the performance of an SFGT. Twelve trained (age: 31.8 ± 6.9 years; body mass index [BMI]: 27.7 ± 3.3 kg·m(-2); VO2peak: 45.6 ± 3.3 ml·kg(-1)·min(-1)) and 37 untrained (age: 31.0 ± 9.0 years; BMI: 31.3 ± 5.2 kg·m(-2); VO2peak: 40.2 ± 5.2 ml·kg(-1)·min(-1)) male career firefighters performed a baseline SFGT. The trained firefighters performed a second SFGT after an exercise session. Time to complete the SFGT, heart rate, and blood lactate were compared between baseline and exercise SFGT (EX-SFGT) conditions. In the trained firefighters, time to complete the SFGT (9.6% increase; p = 0.002) and heart rate (4.1% increase; p = 0.032) were greater during the EX-SFGT compared with baseline, with no difference in post-SFGT blood lactate (p = 0.841). The EX-SFGT time of the trained firefighters was faster than approximately 70% of the untrained firefighters' baseline SFGT time. In addition, the baseline SFGT time of the trained firefighters was faster than 81% of the untrained firefighters. This study demonstrated that on-duty exercise training reduced the work efficiency in firefighters. However, adaptations obtained through regular on-duty exercise training may limit decrements in work efficiency because of acute exercise fatigue and allow for superior work efficiency compared with not participating in a training program.

Effects of Twice-Weekly Intense Aerobic Exercise in Early Subacute Stroke: A Randomized Controlled Trial.

PubMed

Sandberg, Klas; Kleist, Marie; Falk, Lars; Enthoven, Paul

2016-08-01

To examine the effects of 12 weeks of twice-weekly intensive aerobic exercise on physical function and quality of life after subacute stroke. Randomized controlled trial. Ambulatory care. Patients (N=56; 28 women) aged ≥50 years who had a mild stroke (98% ischemic) and were discharged to independent living and enrolled 20 days (median) after stroke onset. Sixty minutes of group aerobic exercise, including 2 sets of 8 minutes of exercise with intensity up to exertion level 14 or 15 of 20 on the Borg rating of perceived exertion scale, twice weekly for 12 weeks (n=29). The nonintervention group (n=27) received no organized rehabilitation or scheduled physical exercise. Primary outcome measures included aerobic capacity on the standard ergometer exercise stress test (peak work rate) and walking distance on the 6-minute walk test (6MWT). Secondary outcome measures included maximum walking speed for 10m, balance on the timed Up and Go (TUG) test and single leg stance (SLS), health-related quality of life on the European Quality of Life Scale (EQ-5D), and participation and recovery after stroke on the Stroke Impact Scale (SIS) version 2.0 domains 8 and 9. Participants were evaluated pre- and postintervention. Patient-reported measures were also evaluated at 6-month follow-up. The following improved significantly more in the intervention group (pre- to postintervention): peak work rate (group × time interaction, P=.006), 6MWT (P=.011), maximum walking speed for 10m (P<.001), TUG test (P<.001), SLS right and left (eyes open) (P<.001 and P=.022, respectively), and SLS right (eyes closed) (P=.019). Aerobic exercise was associated with improved EQ-5D scores (visual analog scale, P=.008) and perceived recovery (SIS domain 9, P=.002). These patient-reported improvements persisted at 6-month follow-up. Intensive aerobic exercise twice weekly early in subacute mild stroke improved aerobic capacity, walking, balance, health-related quality of life, and patient-reported recovery. Copyright © 2016 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Active Video Games as a Training Tool for Individuals With Chronic Respiratory Diseases: A SYSTEMATIC REVIEW.

PubMed

Butler, Stacey J; Lee, Annemarie L; Goldstein, Roger S; Brooks, Dina

2018-02-26

Exercise is an effective treatment for reducing symptom severity and improving quality of life for patients with chronic respiratory diseases. Active video games offer a new and enjoyable way to exercise and have gained popularity in a rehabilitation setting. However, it is unclear whether they achieve comparable physiological and clinical effects as traditional exercise training. A systematic literature search was performed to identify studies that included an active video game component as a form of exercise training and a comparator group in chronic respiratory disease. Two assessors independently reviewed study quality using the Cochrane risk of bias tool and extracted data for exercise capacity, quality of life, and preference of exercise model. Six studies were included in this review. Because of the heterogeneity of the populations, study designs, length of intervention, and outcome measures, meta-analysis could not be performed. Active video game training resulted in comparable training maximal heart rate and dyspnea levels to those achieved when exercising using a treadmill or cycle (n = 5). There was insufficient evidence (n = 3) to determine whether active video game training improved exercise capacity as measured by 6-min walk test or treadmill endurance walking. Although the quality of evidence was low, in a small number of studies active video games induced peak heart rates and dyspnea levels comparable with traditional exercise training. Larger and longer-term randomized controlled trials are needed to establish the impact of video game training for individuals with chronic respiratory diseases.This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal.

Acceptance and commitment therapy improves exercise tolerance in sedentary women.

PubMed

Ivanova, Elena; Jensen, Dennis; Cassoff, Jamie; Gu, Fei; Knäuper, Bärbel

2015-06-01

To test the efficacy of an acute intervention derived from acceptance and commitment therapy (ACT) for increasing high-intensity constant work rate (CWR) cycle exercise tolerance in a group of low-active women age 18-45 yr. The secondary goals were to examine whether ACT would reduce perceived effort and improve in-task affect during exercise and increase postexercise enjoyment. In a randomized controlled trial, 39 women were randomized to either the experimental (using ACT-based cognitive techniques and listening to music during the CWR exercise tests) or a control group (listening to music during the CWR exercise tests). Before (CWR-1) and after the intervention (CWR-2), participants completed a CWR cycle exercise test at 80% of maximal incremental work rate (Wmax) until volitional exhaustion. On average, ACT (n = 18) and control (n = 21) groups were matched for age, body mass index, weekly leisure activity scores, and Wmax (all P > 0.05). Exercise tolerance time (ETT) increased by 15% from CWR-1 to CWR-2 for the ACT group (392.05 ± 146.4 vs 459.39 ± 209.3 s; mean ± SD) and decreased by 8% (384.71 ± 120.1 vs 353.86 ± 127.9 s) for the control group (P = 0.008). RPE were lower (e.g., by 1.5 Borg 6-20 scale units at 55% of ETT, P ≤ 0.01) during CWR-2 in the ACT versus that in the control group. By contrast, ACT had no effect on in-task affect. Exercise enjoyment was higher after CWR-2 in the ACT group versus that in the control group (P < 0.001). An acute ACT intervention increased high-intensity ETT and postexercise enjoyment and reduced perceived effort in low-active women. Further investigations of ACT as an effective intervention for enhancing the established health benefits of high-intensity exercise need to be provided.

Cycle-Powered Short Radius (1.9 m) Centrifuge: Effect of Exercise Versus Passive Acceleration on Heart Rate in Humans

NASA Technical Reports Server (NTRS)

Greenleaf, J. E.; Gundo, D. P.; Watenpaugh, D. E.; Mulenburg, G. M.; Mckenzie, M. A.; Looft-Wilson, R.; Hargens, A. R.

1997-01-01

In addition to extensive use of lower extremity physical exercise training as a countermeasure for the work capacity component of spaceflight deconditioning, some form of additional head-to-foot (+Gz) gravitational (orthostatic) stress may be required to further attenuate or prevent the signs and symptoms (nausea, vertigo, instability, fatigue) of the general reentry syndrome (GRS) that can reduce astronaut performance during landing. Orthostatic (head-to-foot) stress can be induced by standing, by lower body negative pressure, and by +Gz acceleration. One important question is whether acceleration training alone or with concurrent leg exercise would provide sufficient additive stimulation to attenuate the GRS. Use of a new human-powered centrifuge may be the answer. Thus, the purpose for this study was to compare heart rate (HR), i.e., a stress response during human-powered acceleration, in four men (35-62 yr) and two women (30-31 yr) during exercise acceleration versus passive acceleration (by an off-board operator) at 100% (maximal acceleration = A(max)), and at 25%, 50%, and 75% of A(max). Mean (+/-SE) A(max) was 43.7 +/- 1.3 rpm (+3.9 +/- 0.2Gz). Mean HR at exercise A(max) was 189 +/- 13 b/min (50-70 sec run time), and 142 +/- 22 b/min at passive A(max) (40-70 sec run time). Regression of mean HR on the various +Gz levels indicated explained variance (correlations squared) of r(exp 2) = 0.88 (exercise) and r(exp 2) = 0.96 (passive): exercise HR of 107 +/- 4 (25%) to 189 +/- 13 (100%) b/min were 43-50 b/min higher (p less than 0.05) than comparable passive HR of 64 +/- 2 to 142 +/- 22 b/min. Thus, exercise adds significant physiological stress during +Gz acceleration. Inflight use of this combined exercise and acceleration countermeasure may maintain work capacity as well as normalize acceleration and orthostatic tolerances which could attenuate or perhaps eliminate the GRS.

Patterning of physiological and affective responses in older active adults during a maximal graded exercise test and self-selected exercise.

PubMed

Smith, Ashleigh E; Eston, Roger; Tempest, Gavin D; Norton, Belinda; Parfitt, Gaynor

2015-09-01

The American College of Sports Medicine has highlighted the importance of considering the physiological and affective responses to exercise when setting exercise intensity. Here, we examined the relationship between exercise intensity and physiological and affective responses in active older adults. Eighteen participants (60-74 years; 64.4 ± 3.9; 8 women) completed a maximal graded exercise test (GXT) on a treadmill. Since time to exhaustion in the GXT differed between participants, heart rate (HR), oxygen consumption (VO2), affective valence (affect) and rating of perceived exertion (RPE) were expressed relative to the individually determined ventilatory threshold (%atVT). During the GXT, VO2, HR and RPE increased linearly (all P < 0.01). Affect declined initially (but remained positive) (P = 0.03), stabilised around VT (still positive) (P > 0.05) and became negative towards the end of the test (P < 0.01). In a subsequent session, participants completed a 20-min bout of self-selected exercise (at a preferred intensity). Initially, participants chose to exercise below VT (88.2 ± 17.4 %VO2atVT); however, the intensity was adjusted to work at, or above VT (107.7 ± 19.9 %VO2atVT) after 10 min (P < 0.001), whilst affect remained positive. Together, these findings indicate that exercise around VT, whether administered during an exercise test, or self-selected by the participant, is likely to result in positive affective responses in older adults.

Improving the health of mental health staff through exercise interventions: a systematic review.

PubMed

Fibbins, Hamish; Ward, Philip B; Watkins, Andrew; Curtis, Jackie; Rosenbaum, Simon

2018-04-01

Exercise interventions are efficacious in reducing cardiometabolic risk and improving symptoms in people with severe mental illness, yet evidence guiding the implementation and scalability of such efforts is lacking. Given increasing efforts to address the disparity in physical health outcomes facing people with a mental illness, novel approaches to increasing adoption of effective interventions are required. Exercise interventions targeting mental health staff may improve staff health while also creating more positive attitudes towards the role of lifestyle interventions for people experiencing mental illness. We aimed to determine the feasibility, acceptability and effectiveness of exercise interventions delivered to staff working in mental health services. A systematic review was conducted from database inception, until November 2017. Studies recruiting staff participants to receive an exercise intervention were eligible for inclusion. Five studies met the inclusion criteria. Physical health interventions for mental health staff were feasible and acceptable with low dropout rates. Reductions in anthropometric measures and work-related stress were reported. Limited evidence suggests that exercise interventions targeting mental health staff are feasible and acceptable. Further research is required to determine the efficacy of such interventions and the impact such strategies may have on staff culture and patient outcomes.

Evidence of cardiac functional reserve upon exhaustion during incremental exercise to determine VO2max.

PubMed

Elliott, Adrian D; Skowno, Justin; Prabhu, Mahesh; Noakes, Timothy David; Ansley, Les

2015-01-01

There remains considerable debate regarding the limiting factor(s) for maximal oxygen uptake (VO2max). Previous studies have shown that the central circulation may be the primary limiting factor for VO2max and that cardiac work increases beyond VO2max. We sought to evaluate whether the work of the heart limits VO2max during upright incremental cycle exercise to exhaustion. Eight trained men completed two incremental exercise trials, each terminating with exercise at two different rates of work eliciting VO2max (MAX and SUPRAMAX). During each exercise trial we continuously recorded cardiac output using pulse-contour analysis calibrated with a lithium dilution method. Intra-arterial pressure was recorded from the radial artery while pulmonary gas exchange was measured continuously for an assessment of oxygen uptake. The workload during SUPRAMAX (mean±SD: 346.5±43.2 W) was 10% greater than that achieved during MAX (315±39.3 W). There was no significant difference between MAX and SUPRAMAX for Q (28.7 vs 29.4 L/min) or VO2 (4.3 vs 4.3 L/min). Mean arterial pressure was significantly higher during SUPRAMAX, corresponding to a higher cardiac power output (8.1 vs 8.5 W; p<0.06). Despite similar VO2 and Q, the greater cardiac work during SUPRAMAX supports the view that the heart is working submaximally at exhaustion during an incremental exercise test (MAX). 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.

A preliminary investigation on exercise intensities of gardening tasks in older adults.

PubMed

Park, Sin-Ae; Shoemaker, Candice A; Haub, Mark D

2008-12-01

Heart rate (HR) was measured continuously while men (n=6) and women (n=2) ages 71 to 85 years (M=77.4, SD=4.1) completed nine gardening tasks. HR and VO2 from a submaximal graded exercise test were used to estimate gardening VO2, energy expenditure, % HRmax, and metabolic equivalents (METs). Tasks were low to moderate intensity physical activity (1.6-3.6 METs); those which worked the upper and lower body were moderate intensity physical activity while those that worked primarily the upper body were low intensity physical activity.

Cardiorespiratory effects of inelastic chest wall restriction.

PubMed

Miller, Jordan D; Beck, Kenneth C; Joyner, Michael J; Brice, A Glenn; Johnson, Bruce D

2002-06-01

We examined the effects of chest wall restriction (CWR) on cardiorespiratory function at rest and during exercise in healthy subjects in an attempt to approximate the cardiorespiratory interactions observed in clinical conditions that result in restrictive lung and/or chest wall changes and a reduced intrathoracic space. Canvas straps were applied around the thorax and abdomen so that vital capacity was reduced by >35%. Data were acquired at rest and during cycle ergometry at 25 and 45% of peak workloads. CWR elicited significant increases in the flow-resistive work performed on the lung (160%) and the gastric pressure-time integral (>400%) at the higher workload, but it resulted in a decrease in the elastic work performed on the lung (56%) compared with control conditions. With CWR, heart rate increased and stroke volume (SV) fell, resulting in >10% fall in cardiac output at rest and during exercise at matched workloads (P < 0.05). Blood pressure and catecholamines were significantly elevated during CWR exercise conditions (P < 0.05). We conclude that CWR significantly impairs SV during exercise and that a compensatory increase in heart rate does not prevent a significant reduction in cardiac output. O(2) consumption appears to be maintained via increased extraction and a redistribution of blood flow via sympathetic activation.

Within-session responses to high-intensity interval training in spinal cord injury.

PubMed

Astorino, Todd Anthony; Thum, Jacob S

2018-02-01

Completion of high-intensity interval training (HIIT) increases maximal oxygen uptake and health status, yet its feasibility in persons with spinal cord injury is unknown. To compare changes in cardiorespiratory and metabolic variables between two interval training regimes and moderate intensity exercise. Nine adults with spinal cord injury (duration = 6.8 ± 6.2 year) initially underwent determination of peak oxygen uptake. During subsequent sessions, they completed moderate intensity exercise, HIIT, or sprint interval training. Oxygen uptake, heart rate, and blood lactate concentration were measured. Oxygen uptake and heart rate increased (p < 0.05) during both interval training sessions and were similar (p > 0.05) to moderate intensity exercise. Peak oxygen uptake and heart rate were higher (p < 0.05) with HIIT (90% peak oxygen uptake and 99% peak heart rate) and sprint interval training (80% peak oxygen uptake and 96% peak heart rate) versus moderate intensity exercise. Despite a higher intensity and peak cardiorespiratory strain, all participants preferred interval training versus moderate exercise. Examining long-term efficacy and feasibility of interval training in this population is merited, considering that exercise intensity is recognized as the most important variable factor of exercise programming to optimize maximal oxygen uptake. Implications for Rehabilitation Spinal cord injury (SCI) reduces locomotion which impairs voluntary physical activity, typically resulting in a reduction in peak oxygen uptake and enhanced chronic disease risk. In various able-bodied populations, completion of high-intensity interval training (HIIT) has been consistently reported to improve cardiorespiratory fitness and other health-related outcomes, although its efficacy in persons with SCI is poorly understood. Data from this study in 9 men and women with SCI show similar changes in oxygen uptake and heart in response to HIIT compared to a prolonged bout of aerobic exercise, although peak values were higher in response to HIIT. Due to the higher peak metabolic strain induced by HIIT as well as universal preference for this modality versus aerobic exercise as reported in this study, further work testing utility of HIIT in this population is merited.

Exercise holds immediate benefits for affect and cognition in younger and older adults.

PubMed

Hogan, Candice L; Mata, Jutta; Carstensen, Laura L

2013-06-01

Physical activity is associated with improved affective experience and enhanced cognitive processing. Potential age differences in the degree of benefit, however, are poorly understood because most studies examine either younger or older adults. The present study examined age differences in cognitive performance and affective experience immediately following a single bout of moderate exercise. Participants (144 community members aged 19 to 93) were randomly assigned to one of two experimental conditions: (a) exercise (15 min of moderate intensity stationary cycling) or (b) control (15 min completing ratings of neutral IAPS images). Before and after the manipulation, participants completed tests of working memory and momentary affect experience was measured. Results suggest that exercise is associated with increased levels of high-arousal positive affect (HAP) and decreased levels of low-arousal positive affect (LAP) relative to control condition. Age moderated the effects of exercise on LAP, such that younger age was associated with a drop in reported LAP postexercise, whereas the effects of exercise on HAP were consistent across age. Exercise also led to faster RTs on a working memory task than the control condition across age. Self-reported negative affect was unchanged. Overall, findings suggest that exercise may hold important benefits for both affective experience and cognitive performance regardless of age. PsycINFO Database Record (c) 2013 APA, all rights reserved.

Cortisol and interleukin-6 responses during intermittent exercise in two different hot environments with equivalent WBGT.

PubMed

Wright, Heather E; McLellan, Tom M; Stapleton, Jill M; Hardcastle, Stephen G; Kenny, Glen P

2012-01-01

Blood marker concentrations such as cortisol (COR) and interleukin (IL)-6 are commonly used to evaluate the physiological strain associated with work in the heat. It is unclear, however, if hot environments of an equivalent thermal stress, as defined by a similar wet bulb globe temperature (WBGT), result in similar response patterns. This study examined markers of neuroendocrine (COR) and immune (IL-6) responses, as well as the cardiovascular and thermal responses, relative to changes in body heat content measured by whole-body direct calorimetry during work in two different hot environments with equivalent WBGT. Eight males performed a 2-hr heavy intermittent exercise protocol (six 15-min bouts of cycling at a constant rate of metabolic heat production (360W) interspersed by 5-min rest periods) in Hot/Dry (46°C, 10% relative humidity [RH]) and Warm/Humid (33°C, 60% RH) conditions (WBGT ∼ 29°C). Whole-body evaporative and dry heat exchange, change in body heat content (ΔH(b)), rectal temperature (T(re)), and heart rate were measured continuously. Venous blood was obtained at rest (PRE) and the end of each exercise bout for the measurement of changes in plasma volume (PV), plasma protein (an estimate of plasma water changes), COR, and IL-6. Ratings of perceived exertion and thermal sensation were measured during the last minute of each exercise bout. No differences existed for ΔH(b), heart rate, T(re),%ΔPV, plasma protein concentration, perceptual strain (thermal sensation, perceived exertion), and COR between the Hot/Dry and Warm/Humid conditions. IL-6 exhibited an interaction effect (p = 0.041), such that greater increases were observed in the Hot/Dry (Δ = 1.61 pg·mL(-1)) compared with the Warm/Humid (Δ = 0.64 pg·mL(-1)) environment. These findings indicate that work performed in two different hot environments with equivalent WBGT resulted in similar levels of thermal, cardiovascular, and perceptual strain, which support the use of the WBGT stress index. However, the greater IL-6 response in the Hot/Dry requires further research to elucidate the effects of different hot environments and work intensities.

Muscle fatigue during intermittent exercise in individuals with mental retardation.

PubMed

Zafeiridis, Andreas; Giagazoglou, Paraskevi; Dipla, Konstantina; Salonikidis, Konstantinos; Karra, Chrisanthi; Kellis, Eleftherios

2010-01-01

This study examined fatigue profile during intermittent exercise in 10 men with mild to moderate mental retardation (MR) and 10 men without mental retardation (C). They performed 4 x 30s maximal knee extensions and flexions with 1-min rest on an isokinetic dynamometer. Peak torque of flexors (PTFL) and extensors (PTEX), total work (TW), and lactate were measured. Fatigue was calculated as the magnitude of decline (%) in PTFL, PTEX, and TW and as rate of decline (linear slope) in TW from 1st to 4th set. MR had lower PTFL, PTEX, TW, and lactate throughout the protocol than C, while pre-motor time was greater in MR vs. C (p<0.05). MR demonstrated a delayed pattern of reduction in muscular performance. Lower values were observed in MR vs. C in the magnitude of decline for PTEX and TW and the rate of decline for TW. In conclusion, MR exhibit a different fatigue profile during intermittent exercise than C. The lower magnitude and decline rate in neuromuscular performance in MR during intermittent exercise is associated with their lower peak strength, short-term anaerobic capacity, and lactate accumulation. Rehabilitation and sport professionals should consider the differences in fatigue profile when designing intermittent exercise programs for MR. Copyright 2009 Elsevier Ltd. All rights reserved.

Attentional bias to emotional stimuli is altered during moderate- but not high-intensity exercise.

PubMed

Tian, Qu; Smith, J Carson

2011-12-01

Little is known regarding how attention to emotional stimuli is affected during simultaneously performed exercise. Attentional biases to emotional face stimuli were assessed in 34 college students (17 women) using the dot-probe task during counterbalanced conditions of moderate- (heart rate at 45% peak oxygen consumption) and high-intensity exercise (heart rate at 80% peak oxygen consumption) compared with seated rest. The dot-probe task consisted of 1 emotional face (pleasant or unpleasant) paired with a neutral face for 1,000 ms; 256 trials (128 trials for each valence) were presented during each condition. Each condition lasted approximately 10 min. Participants were instructed to perform each trial of the dot-probe task as quickly and accurately as possible during the exercise and rest conditions. During moderate-intensity exercise, participants exhibited significantly greater attentional bias scores to pleasant compared with unpleasant faces (p < .01), whereas attentional bias scores to emotional faces did not differ at rest or during high-intensity exercise (p > .05). In addition, the attentional bias to unpleasant faces was significantly reduced during moderate-intensity exercise compared with that during rest (p < .05). These results provide behavioral evidence that during exercise at a moderate intensity, there is a shift in attention allocation toward pleasant emotional stimuli and away from unpleasant emotional stimuli. Future work is needed to determine whether acute exercise may be an effective treatment approach to reduce negative bias or enhance positive bias in individuals diagnosed with mood or anxiety disorders, or whether attentional bias during exercise predicts adherence to exercise. (c) 2011 APA, all rights reserved.

A study of intensity, fatigue and precision in two specific interval trainings in young tennis players: high-intensity interval training versus intermittent interval training

PubMed Central

Suárez Rodríguez, David; del Valle Soto, Miguel

2017-01-01

Background The aim of this study is to find the differences between two specific interval exercises. We begin with the hypothesis that the use of microintervals of work and rest allow for greater intensity of play and a reduction in fatigue. Methods Thirteen competition-level male tennis players took part in two interval training exercises comprising nine 2 min series, which consisted of hitting the ball with cross-court forehand and backhand shots, behind the service box. One was a high-intensity interval training (HIIT), made up of periods of continuous work lasting 2 min, and the other was intermittent interval training (IIT), this time with intermittent 2 min intervals, alternating periods of work with rest periods. Average heart rate (HR) and lactate levels were registered in order to observe the physiological intensity of the two exercises, along with the Borg Scale results for perceived exertion and the number of shots and errors in order to determine the intensity achieved and the degree of fatigue throughout the exercise. Results There were no significant differences in the average heart rate, lactate or the Borg Scale. Significant differences were registered, on the other hand, with a greater number of shots in the first two HIIT series (series 1 p>0.009; series 2 p>0.056), but not in the third. The number of errors was significantly lower in all the IIT series (series 1 p<0.035; series 2 p<0.010; series 3 p<0.001). Conclusion Our study suggests that high-intensity intermittent training allows for greater intensity of play in relation to the real time spent on the exercise, reduced fatigue levels and the maintaining of greater precision in specific tennis-related exercises. PMID:29021912

Effects of exercise and conditioning on clotting and fibrinolytic activity in men

NASA Technical Reports Server (NTRS)

Ferguson, Earl W.; Bernier, Lani L.; Banta, Guy R.; Yu-Yahiro, Janet; Schoomaker, Eric B.

1987-01-01

Blood clotting and fibrinolytic activity in three groups of nonsmoking, nonobese, healthy men ranging from 19 to 59 years are studied. The groups consisted of (1) marathoners (men running more than 50 miles/week); (2) joggers (men running 5-15 miles/week; and (3) sedentary subjects (men who did not exercise routinely). It is observed that the rate of blood clotting is accelerated by exercise; marathoners had greater increases in fibrinolytic activity than the other two groups; and fibrin degradation products increased with exercise. The data reveal that the changes in clotting assays with exercise do not correlate with changes in whole blood lactate, blood pyruvate, or rectal temperatures. It is noted that the level of acceleration for fibrinolytic activity is directly related to the maximum aerobic capacity and work load of the individual, and that conditioning enhances the fibrinolytic response to exercise.

Effects of body position on the ventilatory response following an impulse exercise in humans.

PubMed

Haouzi, Philippe; Chenuel, Bruno; Chalon, Bernard

2002-04-01

The aim of this study was to identify some of the mechanisms that could be involved in blunted ventilatory response (VE) to exercise in the supine (S) position. The contribution of the recruitment of different muscle groups, the activity of the cardiac mechanoreceptors, the level of arterial baroreceptor stimulation, and the hemodynamic effects of gravity on the exercising muscles was analyzed during upright (U) and S exercise. Delayed rise in VE and pulmonary gas exchange following an impulselike change in work rate (supramaximal leg cycling at 240 W for 12 s) was measured in seven healthy subjects and six heart transplant patients both in U and S positions. This approach allows study of the relationship between the rise in VE and O2 uptake (VO2) without the confounding effects of contractions of different muscle groups. These responses were compared with those triggered by an impulselike change in work rate produced by the arms, which were positioned at the same level as the heart in S and U positions to separate effects of gravity on postexercising muscles from those on the rest of the body. Despite superimposable VO2 and CO2 output responses, the delayed VE response after leg exercise was significantly lower in the S posture than in the U position for each control subject and cardiac-transplant patient (-2.58 +/- 0.44 l and -3.52 +/- 1.11 l/min, respectively). In contrast, when impulse exercise was performed with the arms, reduction of ventilatory response in the S posture reached, at best, one-third of the deficit after leg exercise and was always associated with a reduction in VO2 of a similar magnitude. We concluded that reduction in VE response to exercise in the S position is independent of the types (groups) of muscles recruited and is not critically dependent on afferent signals originating from the heart but seems to rely on some of the effects of gravity on postexercising muscles.

Effects of Strength Training Sessions Performed with Different Exercise Orders and Intervals on Blood Pressure and Heart Rate Variability.

PubMed

Lemos, Sandro; Figueiredo, Tiago; Marques, Silvio; Leite, Thalita; Cardozo, Diogo; Willardson, Jeffrey M; Simão, Roberto

2018-01-01

This study compared the effect of a strength training session performed at different exercise orders and rest intervals on blood pressure and heart rate variability (HRV). Fifteen trained men performed different upper body exercise sequences [large to small muscle mass (SEQA) and small to large muscle mass (SEQB)] in randomized order with rest intervals between sets and exercises of 40 or 90 seconds. Fifteen repetition maximum loads were tested to control the training intensity and the total volume load. The results showed, significant reductions for systolic blood pressure (SBP) for all sequences compared to baseline and, post-exercise: SEQA90 at 20, 30, 40, 50 and 60 minutes; SEQA40 and SEQB40 at 20 minutes and SEQB90 at 10, 20, 30, 40, 50 and 60 minutes. For diastolic blood pressure (DBP), significant reductions were found for three sequences compared to baseline and, post-exercise: SEQA90 and SEQA40 at 50 and 60 minutes; SEQB40 at 10, 30 and 60 minutes. For HRV, there were significant differences in frequency domain for all sequences compared to baseline. In conclusion, when performing upper body strength training sessions, it is suggested that 90 second rest intervals between sets and exercises promotes a post-exercise hypotensive response in SBP. The 40 second rest interval between sets and exercises was associated with greater cardiac stress, and might be contraindicated when working with individuals that exhibit symptoms of cardiovascular disease.

One-minute heart rate recovery after cycloergometer exercise testing as a predictor of mortality in a large cohort of exercise test candidates: substantial differences with the treadmill-derived parameter.

PubMed

Gaibazzi, Nicola; Petrucci, Nicola; Ziacchi, Vigilio

2004-03-01

Previous work showed a strong inverse association between 1-min heart rate recovery (HRR) after exercising on a treadmill and all-cause mortality. The aim of this study was to determine whether the results could be replicated in a wide population of real-world exercise ECG candidates in our center, using a standard bicycle exercise test. Between 1991 and 1997, 1420 consecutive patients underwent ECG exercise testing performed according to our standard cycloergometer protocol. Three pre-specified cut-point values of 1-min HRR, derived from previous studies in the medical literature, were tested to see whether they could identify a higher-risk group for all-cause mortality; furthermore, we tested the possible association between 1-min HRR as a continuous variable and mortality using logistic regression. Both methods showed a lack of a statistically significant association between 1-min HRR and all-cause mortality. A weak trend toward an inverse association, although not statistically significant, could not be excluded. We could not validate the clear-cut results from some previous studies performed using the treadmill exercise test. The results in our study may only "not exclude" a mild inverse association between 1-min HRR measured after cycloergometer exercise testing and all-cause mortality. The 1-min HRR measured after cycloergometer exercise testing was not clinically useful as a prognostic marker.

The role of physical activity and heart rate variability for the control of work related stress.

PubMed

Tonello, Laís; Rodrigues, Fábio B; Souza, Jeniffer W S; Campbell, Carmen S G; Leicht, Anthony S; Boullosa, Daniel A

2014-01-01

Physical activity (PA) and exercise are often used as tools to reduce stress and therefore the risk for developing cardiovascular diseases (CVD). Meanwhile, heart rate variability (HRV) has been utilized to assess both stress and PA or exercise influences. The objective of the present review was to examine the current literature in regards to workplace stress, PA/exercise and HRV to encourage further studies. We considered original articles from known databases (PubMed, ISI Web of Knowledge) over the last 10 years that examined these important factors. A total of seven studies were identified with workplace stress strongly associated with reduced HRV in workers. Longitudinal workplace PA interventions may provide a means to improve worker stress levels and potentially cardiovascular risk with mechanisms still to be clarified. Future studies are recommended to identify the impact of PA, exercise, and fitness on stress levels and HRV in workers and their subsequent influence on cardiovascular health.

Effect of Fontan geometry on exercise haemodynamics and its potential implications.

PubMed

Tang, Elaine; Wei, Zhenglun Alan; Whitehead, Kevin K; Khiabani, Reza H; Restrepo, Maria; Mirabella, Lucia; Bethel, James; Paridon, Stephen M; Marino, Bradley S; Fogel, Mark A; Yoganathan, Ajit P

2017-11-01

Exercise intolerance afflicts Fontan patients with total cavopulmonary connections (TCPCs) causing a reduction in quality of life. Optimising TCPC design is hypothesised to have a beneficial effect on exercise capacity. This study investigates relationships between TCPC geometries and exercise haemodynamics and performance. This study included 47 patients who completed metabolic exercise stress test with cardiac magnetic resonance (CMR). Phase-contrast CMR images were acquired immediately following supine lower limb exercise. Both anatomies and exercise vessel flow rates at ventilatory anaerobic threshold (VAT) were extracted. The vascular modelling toolkits were used to analyse TCPC geometries. Computational simulations were performed to quantify TCPC indexed power loss (iPL) at VAT. A highly significant inverse correlation was found between the TCPC diameter index, which factors in the narrowing of TCPC vessels, with iPL at VAT (r=-0.723, p<0.001) but positive correlations with exercise performance variables, including minute oxygen consumption (VO 2 ) at VAT (r=0.373, p=0.01), VO 2 at peak exercise (r=0.485, p=0.001) and work at VAT/weight (r=0.368, p=0.01). iPL at VAT was negatively correlated with VO 2 at VAT (r=-0.337, p=0.02), VO 2 at peak exercise (r=-0.394, p=0.007) and work at VAT/weight (r=-0.208, p=0.17). Eliminating vessel narrowing in TCPCs and reducing elevated iPL at VAT could enhance exercise tolerance for patients with TCPCs. These findings could help plan surgical or catheter-based strategies to improve patients' exercise capacity. © 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.

Faster heart rate and muscular oxygen uptake kinetics in type 2 diabetes patients following endurance training.

PubMed

Koschate, Jessica; Drescher, Uwe; Brinkmann, Christian; Baum, Klaus; Schiffer, Thorsten; Latsch, Joachim; Brixius, Klara; Hoffmann, Uwe

2016-11-01

Cardiorespiratory kinetics were analyzed in type 2 diabetes patients before and after a 12-week endurance exercise-training intervention. It was hypothesized that muscular oxygen uptake and heart rate (HR) kinetics would be faster after the training intervention and that this would be detectable using a standardized work rate protocol with pseudo-random binary sequences. The cardiorespiratory kinetics of 13 male sedentary, middle-aged, overweight type 2 diabetes patients (age, 60 ± 8 years; body mass index, 33 ± 4 kg·m -2 ) were tested before and after the 12-week exercise intervention. Subjects performed endurance training 3 times a week on nonconsecutive days. Pseudo-random binary sequences exercise protocols in combination with time series analysis were used to estimate kinetics. Greater maxima in cross-correlation functions (CCF max ) represent faster kinetics of the respective parameter. CCF max of muscular oxygen uptake (pre-training: 0.31 ± 0.03; post-training: 0.37 ± 0.1, P = 0.024) and CCF max of HR (pre-training: 0.25 ± 0.04; post-training: 0.29 ± 0.06, P = 0.007) as well as peak oxygen uptake (pre-training: 24.4 ± 4.7 mL·kg -1 ·min -1 ; post-training: 29.3 ± 6.5 mL·kg -1 ·min -1 , P = 0.004) increased significantly over the course of the exercise intervention. In conclusion, kinetic responses to changing work rates in the moderate-intensity range are similar to metabolic demands occurring in everyday habitual activities. Moderate endurance training accelerated the kinetic responses of HR and muscular oxygen uptake. Furthermore, the applicability of the used method to detect these accelerations was demonstrated.

Changes in technique and efficiency after high-intensity exercise in cross-country skiers.

PubMed

Åsan Grasaas, Christina; Ettema, Gertjan; Hegge, Ann Magdalen; Skovereng, Knut; Sandbakk, Øyvind

2014-01-01

This study investigated changes in technique and efficiency after high-intensity exercise to exhaustion in elite cross-country skiers. Twelve elite male skiers completed 4 min submaximal exercise before and after a high-intensity incremental test to exhaustion with the G3 skating technique on a 5% inclined roller-ski treadmill. Kinematics and kinetics were monitored by instrumented roller skis, work rate was calculated as power against roller friction and gravity, aerobic metabolic cost was determined from gas exchange, and blood lactate values indicated the anaerobic contribution. Gross efficiency was the work rate divided by aerobic metabolic rate. A recovery period of 10 min between the incremental test and the posttest was included to allow the metabolic values to return to baseline. Changes in neuromuscular fatigue in upper and lower limbs before and after the incremental test were indicated by peak power in concentric bench press and squat-jump height. From pretest to posttest, cycle length decreased and cycle rate increased by approximately 5% (P < 0.001), whereas the amount of ski forces did not change significantly. Oxygen uptake increased by 4%, and gross efficiency decreased from 15.5% ± 0.7% to 15.2% ± 0.5% from pretest to posttest (both P < .02). Correspondingly, blood lactate concentration increased from 2.4 ± 1.0 to 6.2 ± 2.5 mmol/L (P < .001). Bench-press and squat-jump performance remained unaltered. Elite cross-country skiers demonstrated a less efficient technique and shorter cycle length during submaximal roller-ski skating after high-intensity exercise. However, there were no changes in ski forces or peak power in the upper and lower limbs that could explain these differences.

Norepinephrine spillover at rest and during submaximal exercise in young and old subjects.

PubMed

Mazzeo, R S; Rajkumar, C; Jennings, G; Esler, M

1997-06-01

Aging is associated with elevations in plasma norepinephrine concentrations. The purpose of this investigation was to examine total body and regional norepinephrine spillover as an indicator of sympathetic nerve activity. Eight young (26 +/- 3 yr) and seven old (69 +/- 5 yr) male subjects were studied at rest and during 20 min of submaximal cycling exercise at 50% of peak work capacity. Norepinephrine spillover was determined by continuous intravenous infusion of [3H]norepinephrine. Arterial norepinephrine concentrations were significantly greater at rest for old vs. young subjects (280 +/- 36 vs. 196 +/- 27 ng/ml, respectively). Whereas total norepinephrine spillover did not differ between groups at rest, hepatomesenteric norepinephrine spillover was 50% greater in old subjects compared with their young counterparts (51 +/- 7 vs. 34 +/- 5 ng/min, respectively). Additionally, norepinephrine clearance rates at rest were significantly lower for the old subjects (-23%). During exercise, plasma norepinephrine concentrations increased compared with rest, with old subjects again demonstrating greater values than the young group. Hepatomesenteric norepinephrine spillover was significantly greater (+36%) during exercise for old subjects compared with young; however, no difference was found for whole body spillover rates between age groups. Norepinephrine clearance rates remained depressed (-80%) in the old subjects during exercise. Clearance of epinephrine mirrored that for norepinephrine both at rest and during exercise across age groups. It was concluded that in old subjects, a reduction in norepinephrine clearance and an increase in regional norepinephrine spillover can account for the higher plasma norepinephrine concentrations observed at rest. This relationship is not exacerbated by the stress imposed during an acute bout of exercise.

Effect of altered arterial perfusion pressure on vascular conductance and muscle blood flow dynamic response during exercise in humans.

PubMed

Villar, Rodrigo; Hughson, Richard L

2013-03-01

Changes in vascular conductance (VC) are required to counter changes in muscle perfusion pressure (MPP) to maintain muscle blood flow (MBF) during exercise. We investigated the recruitment of VC as a function of peak VC measured in three body positions at two different work rates to test the hypothesis that adaptations in VC compensated changes in MPP at low-power output (LPO), but not at high-power output (HPO). Eleven healthy volunteers exercised at LPO and HPO (repeated plantar flexion contractions at 20-30% maximal voluntary contraction, respectively) in horizontal (HOR), 35° head-down tilt (HDT), and 45° head-up tilt (HUT). Muscle blood flow velocity and popliteal diameter were measured by ultrasound to determine MBF, and VC was estimated by dividing MBF flow by MPP. Peak VC was unaffected by body position. The rates of increase in MBF and VC were significantly faster in HUT and slower in HDT than HOR, and rates were faster in LPO than HPO. During LPO exercise, the increase in, and steady-state values of, MBF were less for HUT and HDT than HOR; the increase in VC was less in HUT than HOR and HDT. During HPO exercise, MBF in the HDT was reduced compared with HOR and HUT, even though VC reached 92% VC peak, which was greater than HOR, which was, in turn, greater than HUT. Reduced MBF during HPO HDT exercise had the functional consequence of a significant increase in muscle electromyographic index, revealing the effects of MPP on O2 delivery during exercise.

The effect of a walking program on perceived benefits and barriers to exercise in postmenopausal African American women.

PubMed

Williams, Bernadette R; Bezner, Janet; Chesbro, Steven B; Leavitt, Ronnie

2006-01-01

Rates of exercise participation among African Americans is low. Identifying and overcoming perceived benefits/ barriers unique to African American women (AAW) may increase their exercise participation. The purpose of this study was to describe perceived benefits/barriers to exercise in AAW before and after participation in a walking program. Thirty-five postmenopausal AAW participated in a 7-week structured walking program with 2 walking goals. Perceived benefits and barriers to exercise were assessed using the Exercise Benefits/Barriers Scale at the beginning and end of the program. Participants engaged in a postintervention interview to further assess benefits/barriers to exercise participation. Perceived benefits/barriers to exercise did not change significantly with participation in a walking program. Lack of time due to work and family responsibilities affected achievement of the brisk walking goal. Postmenopausal AAW in this study strongly believed in the benefits of exercising and had increased levels of participation in a walking program when lack of time was not a barrier. Overcoming this barrier is the true challenge to health care professionals.

An Examination of the Counting Talk Test's Ability to Discern Individual Variability in Exercise-Induced Metabolic Stress

ERIC Educational Resources Information Center

Bonafiglia, Jacob T.; Sawula, Laura J.; Gurd, Brendon J.

2018-01-01

The purpose of this study was to determine if the counting talk test can be used to discern whether an individual is exercising above or at/below maximal lactate steady state. Twenty-two participants completed VO[subscript 2]peak and counting talk test incremental step tests followed by an endurance test at 65% of work rate at VO[subscript 2]peak…

Assessment of physical demands and fluid balance in elite female handball players during a 6-day competitive tournament.

PubMed

Cunniffe, Brian; Fallan, Carissa; Yau, Adora; Evans, Gethin H; Cardinale, Marco

2015-02-01

Little data exists on drinking behavior, sweat loss, and exercise intensity across a competitive handball tournament in elite female athletes. Heart rate (HR), fluid balance and sweat electrolyte content were assessed on 17 international players across a 6-day tournament involving 5 games and 2 training sessions played indoors (23 ± 2 °C, 30 ± 2% relative humidity). Active play (effective) mean HR was 155 ± 14 bpm (80 ± 7.5% HRmax) with the majority of time (64%) spent exercising at intensities >80% HRmax. Mean (SD) sweat rates during games were 1.02 ± 0.07 L · h⁻¹ and on 56% of occasions fluid intake matched or exceeded sweat loss. A significant relationship was observed between estimated sweat loss and fluid intake during exercise (r² = .121, p = .001). Mean sweat sodium concentration was 38 ± 10 mmol · L⁻¹, with significant associations observed between player sweat rates and time spent exercising at intensities >90% HRmax (r² = .181, p = .001). Fluid and electrolyte loss appear to be work rate dependent in elite female handball players, whom appear well capable of replacing fluids lost within a tournament environment. Due to large between-athlete variations, a targeted approach may be warranted for certain players only.

Effect of work intensity on time delay in mediation of ventilation by arterial carbon dioxide during recovery from impulse exercise.

PubMed

Afroundeh, R; Arimitsu, T; Yamanaka, R; Lian, C S; Shirakawa, K; Yunoki, T; Yano, T

2014-01-01

Time delay in the mediation of ventilation (V(.)E) by arterial CO(2) pressure (PaCO(2)) was studied during recovery from short impulse-like exercises with different work loads of recovery. Subjects performed two tests including 10-s impulse like exercise with work load of 200 watts and 15-min recovery with 25 watts in test one and 50 watts in test two. V(.)E, end tidal CO(2) pressure (PETCO(2)) and heart rate (HR) were measured continuously during rest, warming up, exercise and recovery. PaCO(2) was estimated from PETCO(2) and tidal volume (V(T)). Results showed that predicted arterial CO(2) pressure (PaCO(2 pre)) increased during recovery in both tests. In both tests, V(.)E increased and peaked at the end of exercise. V(.)E decreased in the first few seconds of recovery but started to increase again. The highest correlation coefficient between PaCO(2 pre) and V(.)E was obtained in the time delay of 7 s (r=0.854) in test one and in time delays of 6 s (r=0.451) and 31 s (r=0.567) in test two. HR was significantly higher in test two than in test one. These results indicate that PaCO(2 pre) drives V(.)E with a time delay and that higher work intensity induces a shorter time delay.

Misremembering Past Affect Predicts Adolescents' Future Affective Experience During Exercise.

PubMed

Karnaze, Melissa M; Levine, Linda J; Schneider, Margaret

2017-09-01

Increasing physical activity among adolescents is a public health priority. Because people are motivated to engage in activities that make them feel good, this study examined predictors of adolescents' feelings during exercise. During the 1st semester of the school year, we assessed 6th-grade students' (N = 136) cognitive appraisals of the importance of exercise. Participants also reported their affect during a cardiovascular fitness test and recalled their affect during the fitness test later that semester. During the 2nd semester, the same participants rated their affect during a moderate-intensity exercise task. Affect reported during the moderate-intensity exercise task was predicted by cognitive appraisals of the importance of exercise and by misremembering affect during the fitness test as more positive than it actually was. This memory bias mediated the association between appraising exercise as important and experiencing a positive change in affect during the moderate-intensity exercise task. These findings highlight the roles of both cognitive appraisals and memory as factors that may influence affect during exercise. Future work should explore whether affect during exercise can be modified by targeting appraisals and memories related to exercise experiences.

Misremembering Past Affect Predicts Adolescents’ Future Affective Experience during Exercise

PubMed Central

Karnaze, Melissa M.; Levine, Linda J.; Schneider, Margaret

2018-01-01

Purpose Increasing physical activity among adolescents is a public health priority. Because people are motivated to engage in activities that make them feel good, this study examined predictors of adolescents’ feelings during exercise. Method During the first semester of the school year, we assessed sixth grade students’ (N = 136) cognitive appraisals of the importance of exercise. Participants also reported their affect during a cardiovascular fitness test, and recalled their affect during the fitness test later that semester. During the second semester, the same participants rated their affect during a moderate-intensity exercise task. Results Affect reported during the moderate-intensity exercise task was predicted by cognitive appraisals of the importance of exercise, and by misremembering affect during the fitness test as more positive than it actually was. This memory bias mediated the association between appraising exercise as important and experiencing a positive change in affect during the moderate-intensity exercise task. Conclusion These findings highlight the roles of both cognitive appraisals and memory as factors that may influence affect during exercise. Future work should explore whether affect during exercise can be modified by targeting appraisals and memories related to exercise experiences. PMID:28494196

NIRS and indocyanine-green-determined muscle blood flow during exercise in humans

NASA Astrophysics Data System (ADS)

Boushel, Robert; Ide, Kojiro; Moller-Sorensen, Hasse; Fernandes, Alvito; Pott, Frank; Secher, Niels H.

1998-01-01

We present a method for determination of muscle blood flow (MBF) using near infrared spectroscopy (NIRS) with indocyanine green (ICG) as the tracer. MBF was quantified using the integrated arterial [ICG] and the accumulation of ICG in muscle. MBF was determined together with ICG-assessed cardiac output (CO) at rest and during incremental cycling. To further modify CO, the same work loads were performed after cardio-selective beta blockade by metoprolol. In one subject both MBF (9 to 110 ml (DOT) 100 g-1 (DOT) min-1) and CO increased linearly with work rate (8 to 19 l (DOT) min-1). Under beta blockade, both the increase in MBF and CO were lower: 5 to 70 ml (DOT) 100 g-1 (DOT) min-1 and 5 to 161 DOT min-1, respectively. During exercise with and without beta blockade, MBF increased with work load to represent a larger proportion of CO. Also, NIRS could detect an attenuated increase in MBF manifest by the restrained CO during leg exercise after cardio-selective beta blockade. Both observations indicate that NIRS detection of indocyanine green provides an estimate of muscle blood flow over the range from rest to intense exercise.

NIRS and indocyanine-green-determined muscle blood flow during exercise in humans

NASA Astrophysics Data System (ADS)

Boushel, Robert; Ide, Kojiro; Moller-Sorensen, Hasse; Fernandes, Alvito; Pott, Frank; Secher, Niels H.

1997-12-01

We present a method for determination of muscle blood flow (MBF) using near infrared spectroscopy (NIRS) with indocyanine green (ICG) as the tracer. MBF was quantified using the integrated arterial [ICG] and the accumulation of ICG in muscle. MBF was determined together with ICG-assessed cardiac output (CO) at rest and during incremental cycling. To further modify CO, the same work loads were performed after cardio-selective beta blockade by metoprolol. In one subject both MBF (9 to 110 ml (DOT) 100 g-1 (DOT) min-1) and CO increased linearly with work rate (8 to 19 l (DOT) min-1). Under beta blockade, both the increase in MBF and CO were lower: 5 to 70 ml (DOT) 100 g-1 (DOT) min-1 and 5 to 161 DOT min-1, respectively. During exercise with and without beta blockade, MBF increased with work load to represent a larger proportion of CO. Also, NIRS could detect an attenuated increase in MBF manifest by the restrained CO during leg exercise after cardio-selective beta blockade. Both observations indicate that NIRS detection of indocyanine green provides an estimate of muscle blood flow over the range from rest to intense exercise.

A peripheral governor regulates muscle contraction.

PubMed

MacIntosh, Brian R; Shahi, M Reza S

2011-02-01

Active skeletal muscles are capable of keeping the global [adenosine triphosphate (ATP)] reasonably constant during exercise, whether it is mild exercise, activating a few motor units, or all-out exercise using a substantial mass of muscle. This could only be accomplished if there were regulatory processes in place not only to replenish ATP as quickly as possible, but also to modulate the rate of ATP use when that rate threatens to exceed the rate of ATP replenishment, a situation that could lead to metabolic catastrophe. This paper proposes that there is a regulatory process or "peripheral governor" that can modulate activation of muscle to avoid metabolic catastrophe. A peripheral governor, working at the cellular level, should be able to reduce the cellular rate of ATP hydrolysis associated with muscle contraction by attenuating activation. This would necessarily cause something we call peripheral fatigue (i.e., reduced contractile response to a given stimulation). There is no doubt that peripheral fatigue occurs. It has been demonstrated in isolated muscles, in muscles in situ with no central nervous system input, and in intact human subjects performing voluntary exercise with small muscle groups or doing whole-body exercise. The regulation of muscle activation is achieved in at least 3 ways (decreasing membrane excitability, inhibiting Ca2+ release through ryanodine receptors, and decreasing the availability of Ca2+ in the sarcoplasmic reticulum), making this a highly redundant control system. The peripheral governor attenuates cellular activation to reduce the metabolic demand, thereby preserving ATP and the integrity of the cell.

Exercise Training During +Gz Acceleration

NASA Technical Reports Server (NTRS)

Greenleaf, J. E.; Chou, J. L.; Simonson, S. R.; Jackson, C. G. R.; Barnes, P. R.

1999-01-01

The overall purpose is to study the effect of passive (without exercise) and active (with exercise) +Gz (head-to-foot) acceleration training, using a short-arm (1.9m radius) centrifuge, on post- training maximal oxygen uptake (VO2 max, work capacity) and 70 deg head-up tilt (orthostatic) tolerance in ambulatory subjects to test the hypothesis that (a) both passive and active acceleration training will improve post-training tilt-tolerance, and (b) there will be no difference in tilt-tolerance between passive and active exercise acceleration training because increased hydrostatic and blood pressures, rather than increased muscular metabolism, will provide the major adaptive stimulus. The purpose of the pilot study was to test the hypothesis that there would be no significant difference in the metabolic responses (oxygen uptake, heart rate, pulmonary ventilation, or respiratory exchange ratio) during supine exercise with moderate +Gz acceleration.

Impaired oxidative metabolism increases adenine nucleotide breakdown in McArdle's disease.

PubMed

Sahlin, K; Areskog, N H; Haller, R G; Henriksson, K G; Jorfeldt, L; Lewis, S F

1990-10-01

Two patients with muscle phosphorylase deficiency [McArdle's disease (McA)] were studied during bicycle exercise at 40 (n = 2) and 60 W (n = 1). Peak heart rate was 170 and 162 beats/min, corresponding to approximately 90% of estimated maximal heart rate. Muscle samples were taken at rest and immediately after exercise from the quadriceps femoris. Lactate content remained low in both muscle and blood. Acetylcarnitine, which constitutes a readily available form of acetyl units and thus a substrate for the tricarboxylic acid cycle, was very low in McA patients both at rest and during exercise, corresponding to approximately 17 and 11%, respectively, of that in healthy subjects. Muscle NADH was unchanged during exercise in McA patients in contrast to healthy subjects, in whom NADH increases markedly at high exercise intensities. Despite low lactate levels, arterial plasma NH3 and muscle inosine 5'-monophosphate increased more steeply relative to work load in McA patients than in healthy subjects. The low postexercise levels of lactate, acetylcarnitine, and NADH in McA patients support the idea that exercise performance is limited by the availability of oxidative fuels. Increases in muscle inosine 5'-monophosphate and plasma NH3 indicate that lack of glycogen as an oxidative fuel is associated with adenine nucleotide breakdown and increased deamination of AMP. It is suggested that the early onset of fatigue in McA patients is caused by an insufficient rate of ADP phosphorylation, resulting in transient increases in ADP.

Ice cooling vest on tolerance for exercise under uncompensable heat stress.

PubMed

Kenny, Glen P; Schissler, Andrew R; Stapleton, Jill; Piamonte, Matthew; Binder, Konrad; Lynn, Aaron; Lan, Christopher Q; Hardcastle, Stephen G

2011-08-01

This study was conducted to evaluate the effectiveness of a commercial, personal ice cooling vest on tolerance for exercise in hot (35°C), wet (65% relative humidity) conditions with a nuclear biological chemical suit (NBC). On three separate occasions, 10 male volunteers walked on a treadmill at 3 miles per hour and 2% incline while (a) seminude (denoted CON), (b) dressed with a nuclear, biological, chemical (NBC) suit with an ice vest (V) worn under the suit (denoted NBCwV); or (c) dressed with an NBC suit but without an ice vest (V) (denoted NBCwoV). Participants exercised for 120 min or until volitional fatigue, or esophageal temperature reached 39.5°C. Esophageal temperature (T(es)), heart rate (HR), thermal sensation, and ratings of perceived exertion were measured. Exercise time was significantly greater in CON compared with both NBCwoV and NBCwV (p < 0.05), whereas T(es), thermal sensation, heart rate, and rate of perceived exertion were lower (p < 0.05). Wearing the ice vest increased exercise time (NBCwoV, 103.6 ± 7.0 min; NBCwV, 115.9 ± 4.1 min) and reduced the level of thermal strain, as evidenced by a lower T(es) at end-exercise (NBCwoV, 39.03 ± 0.13°C; NBCwV, 38.74 ± 0.13°C) and reduced thermal sensation (NBCwoV, 6.4 ± 0.4; NBCwV, 4.8 ± 0.6). This was paralleled by a decrease in rate of perceived exertion (NBCwoV, 14.7 ± 1.6; NBCwV, 12.4 ± 1.6) (p < 0.05) and heat rate (NBCwoV, 169 ± 6; NBCwV, 159 ± 7) (p < 0.05). We show that a commercially available cooling vest can significantly reduce the level of thermal strain during work performed in hot environments.

Loss of capacity to recover from acidosis on repeat exercise in chronic fatigue syndrome: a case-control study.

PubMed

Jones, David E J; Hollingsworth, Kieren G; Jakovljevic, Djordje G; Fattakhova, Gulnar; Pairman, Jessie; Blamire, Andrew M; Trenell, Michael I; Newton, Julia L

2012-02-01

Chronic fatigue syndrome (CFS) patients frequently describe difficulties with repeat exercise. Here, we explore muscle bioenergetic function in response to three bouts of exercise. A total of 18 CFS (CDC 1994) patients and 12 sedentary controls underwent assessment of maximal voluntary contraction (MVC), repeat exercise with magnetic resonance spectroscopy and cardio-respiratory fitness test to determine anaerobic threshold. Chronic fatigue syndrome patients undertaking MVC fell into two distinct groups: 8 (45%) showed normal PCr depletion in response to exercise at 35% of MVC (PCr depletion >33%; lower 95% CI for controls); 10 CFS patients had low PCr depletion (generating abnormally low MVC values). The CFS whole group exhibited significantly reduced anaerobic threshold, heart rate, VO(2) , VO(2) peak and peak work compared to controls. Resting muscle pH was similar in controls and both CFS patient groups. However, the CFS group achieving normal PCr depletion values showed increased intramuscular acidosis compared to controls after similar work after each of the three exercise periods with no apparent reduction in acidosis with repeat exercise of the type reported in normal subjects. This CFS group also exhibited significant prolongation (almost 4-fold) of the time taken for pH to recover to baseline. When exercising to comparable levels to normal controls, CFS patients exhibit profound abnormality in bioenergetic function and response to it. Although exercise intervention is the logical treatment for patients showing acidosis, any trial must exclude subjects who do not initiate exercise as they will not benefit. This potentially explains previous mixed results in CFS exercise trials. © 2011 The Authors. European Journal of Clinical Investigation © 2011 Stichting European Society for Clinical Investigation Journal Foundation.

Effects of movement and work load in patients with congenital central hypoventilation syndrome.

PubMed

Hager, Alfred; Koch, Walter; Stenzel, Heike; Hess, John; Schöber, Johannes

2007-04-01

Patients with congenital central hypoventilation syndrome lack ventilatory chemosensitivity and depend at least in part on the ergoreceptor function during exercise. In these patients a substantial increase of ventilation has been reported for passive movement during sleep as well as active movement on a treadmill. The aim of the study was to investigate ventilatory response to an increasing work load with constant movement. Eighteen patients and 17 healthy volunteers performed a cardiopulmonary exercise test on a bicycle pedaling at a constant rate of about 60 revolutions per minute throughout the entire test. The patients were able to exercise adequately and showed normal peak oxygen uptake. There was a steep rise in minute ventilation in both groups at the start of exercise, yet there was only a minor increase in both groups during the increase of workload up to the anaerobic threshold. After the anaerobic threshold, there was again an increase in ventilation in both groups, but the increase was less prominent in the patient group. Ventilation in patients with congenital central hypoventilation syndrome is increased during exercise caused both by movement (mechanoreceptors) and by anaerobic workload. This facilitates a normal ventilatory drive up to the anaerobic threshold and a normal exercise capacity in these patients.

Test-retest reliability and four-week changes in cardiopulmonary fitness in stroke patients: evaluation using a robotics-assisted tilt table.

PubMed

Saengsuwan, Jittima; Berger, Lucia; Schuster-Amft, Corina; Nef, Tobias; Hunt, Kenneth J

2016-09-06

Exercise testing devices for evaluating cardiopulmonary fitness in patients with severe disability after stroke are lacking, but we have adapted a robotics-assisted tilt table (RATT) for cardiopulmonary exercise testing (CPET). Using the RATT in a sample of patients after stroke, this study aimed to investigate test-retest reliability and repeatability of CPET and to prospectively investigate changes in cardiopulmonary outcomes over a period of four weeks. Stroke patients with all degrees of disability underwent 3 separate CPET sessions: 2 tests at baseline (TB1 and TB2) and 1 test at follow up (TF). TB1 and TB2 were at least 24 h apart. TB2 and TF were 4 weeks apart. A RATT equipped with force sensors in the thigh cuffs, a work rate estimation algorithm and a real-time visual feedback system was used to guide the patients' exercise work rate during CPET. Test-retest reliability and repeatability of CPET variables were analysed using paired t-tests, the intraclass correlation coefficient (ICC), the coefficient of variation (CoV), and Bland and Altman limits of agreement. Changes in cardiopulmonary fitness during four weeks were analysed using paired t-tests. Seventeen sub-acute and chronic stroke patients (age 62.7 ± 10.4 years [mean ± SD]; 8 females) completed the test sessions. The median time post stroke was 350 days. There were 4 severely disabled, 1 moderately disabled and 12 mildly disabled patients. For test-retest, there were no statistically significant differences between TB1 and TB2 for most CPET variables. Peak oxygen uptake, peak heart rate, peak work rate and oxygen uptake at the ventilatory anaerobic threshold (VAT) and respiratory compensation point (RCP) showed good to excellent test-retest reliability (ICC 0.65-0.94). For all CPET variables, CoV was 4.1-14.5 %. The mean difference was close to zero in most of the CPET variables. There were no significant changes in most cardiopulmonary performance parameters during the 4-week period (TB2 vs TF). These findings provide the first evidence of test-retest reliability and repeatability of the principal CPET variables using the novel RATT system and testing methodology, and high success rates in identification of VAT and RCP: good to excellent test-retest reliability and repeatability were found for all submaximal and maximal CPET variables. Reliability and repeatability of the main CPET parameters in stroke patients on the RATT were comparable to previous findings in stroke patients using standard exercise testing devices. The RATT has potential to be used as an alternative exercise testing device in patients who have limitations for use of standard exercise testing devices.

Effects of bench step exercise intervention on work ability in terms of cardiovascular risk factors and oxidative stress: a randomized controlled study.

PubMed

Ohta, Masanori; Eguchi, Yasumasa; Inoue, Tomohiro; Honda, Toru; Morita, Yusaku; Konno, Yoshimasa; Yamato, Hiroshi; Kumashiro, Masaharu

2015-01-01

Work ability is partly determined by physical and mental fitness. Bench step exercise can be practiced anywhere at any time. The aim of this study was to determine the effects of a bench step exercise on work ability by examining cardiovascular risk factors and oxidative stress. Thirteen volunteers working in a warehousing industry comprised the bench step exercise group (n=7) and the control group (n=6). The participants in the step exercise group were encouraged to practice the step exercise at home for 16 weeks. The step exercise improved glucose metabolism and antioxidative capacity and increased work ability by reducing absences from work and improving the prognosis of work ability. The improvement in work ability was related to a reduction in oxidative stress. These results suggest that a bench step exercise may improve work ability by reducing cardiovascular risk factors and oxidative stress.

Peak Cardiorespiratory Responses of Patients with Subacute Stroke During Land and Aquatic Treadmill Exercise.

PubMed

Lee, Yong Ki; Kim, Bo Ryun; Han, Eun Young

2017-05-01

The aim of this work was to investigate the cardiorespiratory responses of patients with subacute stroke to exercise stress tests with aquatic and land treadmills. Twenty-one consecutive patients who presented with first-ever subacute stroke in 2013-2015. All subjects underwent symptom-limited incremental exercise testing with aquatic and land treadmills. Land treadmill speed started at 1.5 km/h and increased 0.5 km/h every 1 to 2 minutes until maximal tolerable speed was achieved. Thereafter, the grade was elevated by 2% every 2 minutes. In the aquatic treadmill test, subjects were submerged to the xiphoid in 28°C water. Treadmill speed started at 1.5 km/h and was increased 0.5 km/h every 2 minutes thereafter. Cardiorespiratory responses were recorded with aquatic and land treadmills. Compared to land treadmill exercise, aquatic treadmill exercise achieved significantly better peak VO2 (22.0 vs 20.0; P = 0.02), peak metabolic equivalents (6.3 vs 5.8; P = 0.02), and peak rating of perceived exertion (17.6 vs 18.4, P = 0.01). Heart rate and VO2 correlated significantly during both tests (land treadmill: r = 0.96, P < 0.001; aquatic treadmill: r = 0.99, P < 0.001). Aquatic treadmill exercise elicited significantly better peak cardiorespiratory responses than land treadmill exercise and may be as effective for early intensive aerobic training in subacute stroke patients.

Exercise training utilizing body weight-supported treadmill walking with a young adult with cerebral palsy who was non-ambulatory.

PubMed

DiBiasio, Paula A; Lewis, Cynthia L

2012-11-01

The purpose of this case report is to determine the effects of exercise training using body weight-supported treadmill walking (BWSTW) with an 18-year-old male diagnosed with Cerebral palsy (CP) who was non-ambulatory and not receiving physical therapy. Outcome measures included the Pediatric Quality of Life Inventory (PedsQL), the Pediatric Evaluation of Disability Inventory (PEDI), heart rate (HR), rate of perceived exertion, 3-minute walk test and physiological cost index (PCI). BWSTW sessions took place twice a week for 6 weeks with a reduction of approximately 40% of the patient's weight. Over-ground 3-minute walk test distance and PCI were essentially unchanged. BWSTW exercise time increased by 67% with a 43% increase in speed while average working HR decreased by 8%. BWSTW PCI decreased by 26%. PedsQL parent report improved in all domains. PedsQL self-report demonstrated a mild decrease. PEDI showed improvements in self-care and mobility. Exercise utilizing BWSTW resulted in a positive training effect for this young adult with CP who was non-ambulatory. Developing effective and efficient protocols for exercise training utilizing BWSTW may aid in the use of this form of exercise and further quantify outcomes. Ensuring that young adults with CP have safe and feasible options to exercise and be physically active on a regular basis is an important role of a physical therapist.

Comparison of estimated core body temperature measured with the BioHarness and rectal temperature under several heat stress conditions.

PubMed

Seo, Yongsuk; DiLeo, Travis; Powell, Jeffrey B; Kim, Jung-Hyun; Roberge, Raymond J; Coca, Aitor

2016-08-01

Monitoring and measuring core body temperature is important to prevent or minimize physiological strain and cognitive dysfunction for workers such as first responders (e.g., firefighters) and military personnel. The purpose of this study is to compare estimated core body temperature (Tco-est), determined by heart rate (HR) data from a wearable chest strap physiology monitor, to standard rectal thermometry (Tre) under different conditions.  Tco-est and Tre measurements were obtained in thermoneutral and heat stress conditions (high temperature and relative humidity) during four different experiments including treadmill exercise, cycling exercise, passive heat stress, and treadmill exercise while wearing personal protective equipment (PPE).  Overall, the mean Tco-est did not differ significantly from Tre across the four conditions. During exercise at low-moderate work rates under heat stress conditions, Tco-est was consistently higher than Tre at all-time points. Tco-est underestimated temperature compared to Tre at rest in heat stress conditions and at a low work rate under heat stress while wearing PPE. The mean differences between the two measurements ranged from -0.1 ± 0.4 to 0.3 ± 0.4°C and Tco-est correlated well with HR (r = 0.795 - 0.849) and mean body temperature (r = 0.637 - 0.861).  These results indicate that, the comparison of Tco-est to Tre may result in over- or underestimation which could possibly lead to heat-related illness during monitoring in certain conditions. Modifications to the current algorithm should be considered to address such issues.

The Effect of Breakfast Prior to Morning Exercise on Cognitive Performance, Mood and Appetite Later in the Day in Habitually Active Women

PubMed Central

Veasey, Rachel C.; Haskell-Ramsay, Crystal F.; Kennedy, David O.; Tiplady, Brian; Stevenson, Emma J.

2015-01-01

Pre-exercise nutritional practices for active females exercising for mood, cognitive and appetite benefits are not well established. Results from an initial field pilot study showed that higher energy intake at breakfast was associated with lower fatigue and higher overall mood and alertness post-exercise (all p < 0.05). In a follow-up, randomised, controlled trial, 24 active women completed three trials in a balanced, cross-over design. At 0815 h participants completed baseline cognitive tasks, mood and appetite visual analogue scales (VAS) and were administered a cereal breakfast (providing 118 or 236 kcal) or no breakfast. After 45 min, they completed a 30 min run at 65% heart rate reserve (HRR). Parameters were re-assessed immediately after exercise, then hourly until lunch (~1240 h), immediately post-lunch and at 1500 and 1900 h via a mobile phone. Breakfast enhanced feelings of relaxation before lunch (p < 0.05, d > 0.40), though breakfast was detrimental for working memory mid-afternoon (p = 0.019, d = 0.37) and mental fatigue and tension later in the day (all p < 0.05, d > 0.038). Breakfast was also beneficial for appetite control before lunch irrespective of size (all p < 0.05, d > 0.43). These data provide information on pre-exercise nutritional practices for active females and suggest that a small breakfast eaten prior to exercise can benefit post-exercise mood and subjective appetite ratings. PMID:26184302

The Effect of Breakfast Prior to Morning Exercise on Cognitive Performance, Mood and Appetite Later in the Day in Habitually Active Women.

PubMed

Veasey, Rachel C; Haskell-Ramsay, Crystal F; Kennedy, David O; Tiplady, Brian; Stevenson, Emma J

2015-07-14

Pre-exercise nutritional practices for active females exercising for mood, cognitive and appetite benefits are not well established. Results from an initial field pilot study showed that higher energy intake at breakfast was associated with lower fatigue and higher overall mood and alertness post-exercise (all p < 0.05). In a follow-up, randomised, controlled trial, 24 active women completed three trials in a balanced, cross-over design. At 0815 h participants completed baseline cognitive tasks, mood and appetite visual analogue scales (VAS) and were administered a cereal breakfast (providing 118 or 236 kcal) or no breakfast. After 45 min, they completed a 30 min run at 65% heart rate reserve (HRR). Parameters were re-assessed immediately after exercise, then hourly until lunch (~1240 h), immediately post-lunch and at 1500 and 1900 h via a mobile phone. Breakfast enhanced feelings of relaxation before lunch (p < 0.05, d > 0.40), though breakfast was detrimental for working memory mid-afternoon (p = 0.019, d = 0.37) and mental fatigue and tension later in the day (all p < 0.05, d > 0.038). Breakfast was also beneficial for appetite control before lunch irrespective of size (all p < 0.05, d > 0.43). These data provide information on pre-exercise nutritional practices for active females and suggest that a small breakfast eaten prior to exercise can benefit post-exercise mood and subjective appetite ratings.

The slow component of O(2) uptake is not accompanied by changes in muscle EMG during repeated bouts of heavy exercise in humans.

PubMed

Scheuermann, B W; Hoelting, B D; Noble, M L; Barstow, T J

2001-02-15

1. We hypothesized that either the recruitment of additional muscle motor units and/or the progressive recruitment of less efficient fast-twitch muscle fibres was the predominant contributor to the additional oxygen uptake (VO2) observed during heavy exercise. Using surface electromyographic (EMG) techniques, we compared the VO2 response with the integrated EMG (iEMG) and mean power frequency (MPF) response of the vastus lateralis with the VO2 response during repeated bouts of moderate (below the lactate threshold, < LT) and heavy (above the lactate threshold, > LT) intensity cycle ergometer exercise. 2. Seven male subjects (age 29 +/- 7 years, mean +/- S.D.) performed three transitions to a work rate (WR) corresponding to 90 % LT and two transitions to a work rate that would elicit a VO2 corresponding to 50 % of the difference between peak VO2 and the LT (i.e. Delta50 %, > LT1 and > LT2). 3. The VO2 slow component was significantly reduced by prior heavy intensity exercise (> LT1, 410 +/- 196 ml min(-1); > LT2, 230 +/- 191 ml min-1). The time constant (tau), amplitude (A) and gain (DeltaVO2/DeltaWR) of the primary VO2 response (phase II) were not affected by prior heavy exercise when a three-component, exponential model was used to describe the V2 response. 4. Integrated EMG and MPF remained relatively constant and at the same level throughout both > LT1 and > LT2 exercise and therefore were not associated with the VO2 slow component. 5. These data are consistent with the view that the increased O2 cost (i.e. VO2 slow component) associated with performing heavy exercise is coupled with a progressive increase in ATP requirements of the already recruited motor units rather than to changes in the recruitment pattern of slow versus fast-twitch motor units. Further, the lack of speeding of the kinetics of the primary VO2 component with prior heavy exercise, thought to represent the initial muscle VO2 response, are inconsistent with O2 delivery being the limiting factor in V > O2 kinetics during heavy exercise.

Postexercise cold-water immersion improves intermittent high-intensity exercise performance in normothermia.

PubMed

McCarthy, Avina; Mulligan, James; Egaña, Mikel

2016-11-01

A brief cold water immersion between 2 continuous high-intensity exercise bouts improves the performance of the latter compared with passive recovery in the heat. We investigated if this effect is apparent in normothermic conditions (∼19 °C), employing an intermittent high-intensity exercise designed to reflect the work performed at the high-intensity domain in team sports. Fifteen young active men completed 2 exhaustive cycling protocols (Ex1 and Ex2: 12 min at 85% ventilatory threshold (VT) and then an intermittent exercise alternating 30-s at 40% peak power (P peak ) and 30 s at 90% P peak to exhaustion) separated by 15 min of (i) passive rest, (ii) 5-min cold-water immersion at 8 °C, and (iii) 10-min cold-water immersion at 8 °C. Core temperature, heart rate, rates of perceived exertion, and oxygen uptake kinetics were not different during Ex1 among conditions. Time to failure during the intermittent exercise was significantly (P < 0.05) longer during Ex2 following the 5- and 10-min cold-water immersions (7.2 ± 3.5 min and 7.3 ± 3.3 min, respectively) compared with passive rest (5.8 ± 3.1 min). Core temperature, heart rate, and rates of perceived exertion were significantly (P < 0.05) lower during most periods of Ex2 after both cold-water immersions compared with passive rest. The time constant of phase II oxygen uptake response during the 85% VT bout of Ex2 was not different among the 3 conditions. A postexercise, 5- to 10-min cold-water immersion increases subsequent intermittent high-intensity exercise compared with passive rest in normothermia due, at least in part, to reductions in core temperature, circulatory strain, and effort perception.

The effect of a short-term high-intensity circuit training program on work capacity, body composition, and blood profiles in sedentary obese men: a pilot study.

PubMed

Miller, Matthew B; Pearcey, Gregory E P; Cahill, Farrell; McCarthy, Heather; Stratton, Shane B D; Noftall, Jennifer C; Buckle, Steven; Basset, Fabien A; Sun, Guang; Button, Duane C

2014-01-01

The objective of this study was to determine how a high-intensity circuit-training (HICT) program affects key physiological health markers in sedentary obese men. Eight obese (body fat percentage >26%) males completed a four-week HICT program, consisting of three 30-minute exercise sessions per week, for a total of 6 hours of exercise. Participants' heart rate (HR), blood pressure (BP), rating of perceived exertion, total work (TW), and time to completion were measured each exercise session, body composition was measured before and after HICT, and fasting blood samples were measured before throughout, and after HICT program. Blood sample measurements included total cholesterol, triacylglycerides, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, glucose, and insulin. Data were analyzed by paired t-tests and one-way ANOVA with repeated measures. Statistical significance was set to P < 0.05. Data analyses revealed significant (P < 0.05) improvements in resting HR (16% decrease), systolic BP (5.5% decrease), TW (50.7%), fat tissue percentage (3.6%), lean muscle tissue percentage (2%), cholesterol (13%), triacylglycerol (37%), and insulin (18%) levels from before to after HICT program. Overall, sedentary obese males experienced a significant improvement in biochemical, physical, and body composition characteristics from a HICT program that was only 6 hours of the total exercise.

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

PubMed

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

2017-07-01

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

Carotid Baroreflex Function During Prolonged Exercise

NASA Technical Reports Server (NTRS)

Raven, P. B.

1999-01-01

Astronauts are often required to work (exercise) at moderate to high intensities for extended periods while performing extra-vehicular activities (EVA). Although the physiologic responses associated with prolonged exercise have been documented, the mechanisms involved in blood pressure regulation under these conditions have not yet been fully elucidated. An understanding of this issue is pertinent to the ability of humans to perform work in microgravity and complies with the emphasis of NASA's Space Physiology and Countermeasures Program. Prolonged exercise at a constant workload is know to result in a progressive decrease in mean arterial pressure (MAP) concomitant with a decrease in stroke volume and a compensatory increase in heart rate. The continuous decrease in MAP during the exercise, which is related to the thermoregulatory redistribution of circulating blood volume to the cutaneous circulation, raises the question as to whether there is a loss of baroreflex regulation of arterial blood pressure. We propose that with prolongation of the exercise to 60 minutes, progressive increases on central command reflect a progressive upward resetting of the carotid baroreflex (CBR) such that the operating point of the CBR is shifted to a pressure below the threshold of the reflex rendering it ineffectual in correcting the downward drift in MAP. In order to test this hypothesis, experiments have been designed to uncouple the global hemodynamic response to prolonged exercise from the central command mediated response via: (1) continuous maintenance of cardiac filling volume by intravenous infusion of a dextran solution; and (2) whole body surface cooling to counteract thermoregulatory cutaneous vasodialation. As the type of work (exercise) performed by astronauts is inherently arm and upper body dependent, we will also examine the physiologic responses to prolonged leg cycling and arm ergometry exercise in the supine positions with and without level lower body negative pressure (-10 torr) to mimic spaceflight- related decreases in cardiac filling volumes.

Carbohydrate Dependence During Prolonged, Intense Endurance Exercise.

PubMed

Hawley, John A; Leckey, Jill J

2015-11-01

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

Dual-cycle ergometry as an exercise modality during prebreathe with 100 percent oxygen

NASA Technical Reports Server (NTRS)

Heaps, Cristine L.; Fischer, Michele D.; Webb, James T.

1994-01-01

In an effort to reduce prebreathe time requirements prior to extravehicular activities and high-altitude flights, a combined arm and leg exercise task proposes to enhance denitrogenation by incorporation of both upper and lower body musculature at a moderately high work intensity during prebreathe with 100% oxygen. Preliminary findings indicated peak oxygen consumption (VO2peak) levels attained on the dual-cycle ergometer do not differ significantly from those levels attained on the treadmill. Eight male subjects were exercised to VO2peak using leg-only cycle ergometry and dual-cycle ergometry on separate days. Preliminary data during dual-cycle ergometry showed arm work equaling 30% of the leg workrate at each stage of the incremental test resulted in arm fatigue in several subjects and a reduced VO2peak compared to dual-cycle ergometry with arm work at 20%. Thus, the 20% workrate was used during the dual-cycle VO2peak trial. On a third experimental day, subjects performed a 10 minute exercise test at a workrate required to elicit 75% of VO2peak for each subject on the dual-cycle ergometer. Blood lactate response to the exercise was monitored as an objective measure of fatigue. Peak VO2 levels attained on the leg-only and the dual-cycle ergometry tasks were not significantly different. Blood lactate levels were significantly elevated following the dual-cycle ergometry at 75% VO2peak. However, lactate levels show the expected rate of decline during recovery and, as demonstrated in the literature, should return to baseline levels within 30 minutes following exercise cessation. Thus, dual-cycle ergometry at 75% VO2peak appears to be a valid exercise for use during prebreathe and should not contribute to fatigue during subsequent EVA's.

Exercising at work: barriers to women's participation.

PubMed

Verhoef, M J; Hamm, R D; Love, E J

1993-06-01

Only a minority of women in an urban random sample have the opportunity to exercise at work, and even fewer women use these opportunities. Lack of time and inconvenient times are the major reasons for not participating in exercise programs at work. Exercise programs at work are used by women who are already physically active, suggesting that workplace exercise programs do not serve the needs of women who may need exercise programs most. Multivariate analysis shows that age, having children, lack of energy, and lack of support are significant barriers to women's exercise participation at work. The results of this study suggest a leadership opportunity for on site occupational health nurses in addressing these barriers to workplace exercise.

Acute and Post-Exercise Physiological Responses to High-Intensity Interval Training in Endurance and Sprint Athletes.

PubMed

Cipryan, Lukas; Tschakert, Gerhard; Hofmann, Peter

2017-06-01

The purpose of the presented study was to compare acute and post-exercise differences in cardiorespiratory, metabolic, cardiac autonomic, inflammatory and muscle damage responses to high-intensity interval exercise (HIIT) between endurance and sprint athletes. The study group consisted of sixteen highly-trained males (age 22.1 ± 2.5 years) participating in endurance (n = 8) or sprint (n = 8) sporting events. All the participants underwent three exercise sessions: short HIIT (work interval duration 30s), long HIIT (3min) and constant load exercise (CE). The exercise interventions were matched for mean power, total time and in case of HIIT interventions also for work-to-relief ratio. The acute cardiorespiratory (HR, V̇ O 2 , RER) and metabolic (lactate) variables as well as the post-exercise changes (up to 3 h) in the heart rate variability, inflammation (interleukin-6, leucocytes) and muscle damage (creatine kinase, myoglobin) were monitored. Endurance athletes performed exercise interventions with moderately (CE) or largely (both HIIT modes) higher mean V̇ O 2 . These differences were trivial/small when V̇ O 2 was expressed as a percentage of V̇ O 2max . Moderately to largely lower RER and lactate values were found in endurance athletes. Markers of cardiac autonomic regulation, inflammation and muscle damage did not reveal any considerable differences between endurance and sprint athletes. In conclusions, endurance athletes were able to perform both HIIT formats with increased reliance on aerobic metabolic pathways although exercise intensity was identical in relative terms for all the participants. However, other markers of the acute and early post-exercise physiological response to these HIIT interventions indicated similarities between endurance and sprint athletes.

PoleStriding exercise and vitamin E for management of peripheral vascular disease.

PubMed

Collins, Eileen G; Edwin Langbein, W; Orebaugh, Cynthia; Bammert, Christine; Hanson, Karla; Reda, Domenic; Edwards, Lonnie C; Littooy, Fred N

2003-03-01

The purpose of this investigation was to evaluate the efficacy of PoleStriding exercise (a form of walking that uses muscles of the upper and lower body in a continuous movement similar to cross-country skiing) and vitamin E (alpha-tocopherol) to improve walking ability and perceived quality of life (QOL) of patients with claudication pain secondary to peripheral arterial disease (PAD). Fifty-two subjects were randomized into four groups: PoleStriding with vitamin E (N = 13), PoleStriding with placebo (N= 14), vitamin E without exercise (N= 13), and placebo without exercise (N = 12). The dose of vitamin E was 400 IU daily. Only the PoleStriding with vitamin E and PoleStriding with placebo groups received PoleStriding instruction and training. Assignment to vitamin E or placebo was double blind. Subjects trained three times weekly for 30-45 min (rest time excluded). Individuals in vitamin E and placebo groups came to the laboratory biweekly for ankle blood-pressure measurements. Results of this randomized clinical trial provide strong evidence that PoleStriding significantly (P< 0.001) improved exercise tolerance on the constant work-rate and incremental treadmill tests. Ratings of perceived claudication pain were significantly less after the PoleStriding training program (P= 0.02). In contrast, vitamin E did not have a statistically significant effect on the subjects' ratings of perceived leg pain (P= 0.35) or treadmill walking duration ( P= 0.36). Perceived distance and walking speed (Walking Impairment Questionnaire) and perceived physical function (Rand Short Form-36) improved in the PoleStriding trained group only (P< 0.001, 0.022 and 0.003, respectively). PoleStriding effectively improved the exercise tolerance and perceived QOL of patients with PAD. Little additional benefit to exercise capacity was realized from vitamin E supplementation.

Step climbing capacity in patients with pulmonary hypertension.

PubMed

Fox, Benjamin Daniel; Langleben, David; Hirsch, Andrew; Boutet, Kim; Shimony, Avi

2013-01-01

Patients with pulmonary hypertension (PH) typically have exercise intolerance and limitation in climbing steps. To explore the exercise physiology of step climbing in PH patients, on a laboratory-based step test. We built a step oximetry system from an 'aerobics' step equipped with pressure sensors and pulse oximeter linked to a computer. Subjects mounted and dismounted from the step until their maximal exercise capacity or 200 steps was achieved. Step-count, SpO(2) and heart rate were monitored throughout exercise and recovery. We derived indices of exercise performance, desaturation and heart rate. A 6-min walk test and serum NT-proBrain Natriuretic Peptide (BNP) level were measured. Lung function tests and hemodynamic parameters were extracted from the medical record. Eighty-six subjects [52 pulmonary arterial hypertension (PAH), 14 chronic thromboembolic PH (CTEPH), 20 controls] were recruited. Exercise performance (climbing time, height gained, velocity, energy expenditure, work-rate and climbing index) on the step test was significantly worse with PH and/or worsening WHO functional class (ANOVA, p < 0.001). There was a good correlation between exercise performance on the step and 6-min walking distance-climb index (r = -0.77, p < 0.0001). The saturation deviation (mean of SpO(2) values <95 %) on the step test correlated with diffusion capacity of the lung (ρ = -0.49, p = 0.001). No correlations were found between the step test indices and other lung function tests, hemodynamic parameters or NT-proBNP levels. Patients with PAH/CTEPH have significant limitation in step climbing ability that correlates with functional class and 6-min walking distance. This is a significant impediment to their daily activities.

Control of the exercise hyperpnoea in humans: a modeling perspective.

PubMed

Ward, S A

2000-09-01

Models of the exercise hyperpnoea have classically incorporated elements of proportional feedback (carotid and medullary chemosensory) and feedforward (central and/or peripheral neurogenic) control. However, the precise details of the control process remain unresolved, reflecting in part both technical and interpretational limitations inherent in isolating putative control mechanisms in the intact human, and also the challenges to linear control theory presented by multiple-input integration, especially with regard to the ventilatory and gas-exchange complexities encountered at work rates which engender a metabolic acidosis. While some combination of neurogenic, chemoreflex and circulatory-coupled processes are likely to contribute to the control, the system appears to evidence considerable redundancy. This, coupled with the lack of appreciable error signals in the mean levels of arterial blood gas tensions and pH over a wide range of work rates, has motivated the formulation of innovative control models that reflect not only spatial interactions but also temporal interactions (i.e. memory). The challenge is to discriminate between robust competing control models that: (a) integrate such processes within plausible physiological equivalents; and (b) account for both the dynamic and steady-state system response over a range of exercise intensities. Such models are not yet available.

Effects of graded load of artificial gravity on cardiovascular functions in humans.

PubMed

Iwase, Satoshi; Fu, Qi; Narita, Kenichi; Morimoto, Eiichi; Takada, Hiroki; Mano, Tadaaki

2002-12-01

An artificial gravity and ergometric exercise loading device for human use was manufactured. It has the capacity of a max 2 G-load at the heart level, and a max 150 W of work-load. Eight subjects (six completed) were subjected to four repeated trials with or without 20 W ergometric exercise. Anti-G score, defined as the G-load x running time to the endpoint, was significantly higher in the exercise trials than standing trials. Heart rate (HR), mean arterial pressure (MAP), thoracic fluid index (TFI) were significantly superior during the exercise trials. Artificial gravity by centrifuge at 1.2 or 1.4 G with 40 or 60 W of ergometric workload may be an excellent countermeasure against cardiovascular deconditioning after long exposure to microgravity.

Physiological responses during graded treadmill exercise in chemical-resistant personal protective equipment.

PubMed

Northington, William E; Suyama, Joe; Goss, Fredric L; Randall, Colby; Gallagher, Michael; Hostler, David

2007-01-01

As the likelihood of terrorist acts increases, prehospital personnel have been forced to train in the proper use of chemical-resistant personal protective equipment (PPE). This protective ensemble has been reported to be physiologically taxing for the wearer, imposing an additional thermal load resulting in hypohydration, hyperthermia, and reduced work time. Victim extrication, the rescue-the-rescuer role of the rapid intervention team and rapid self-extrication, typically requires high-intensity work that can be maintained only for short time intervals. The additional physiological burden imparted by the level C PPE during high-intensity work is unknown. We hypothesized that the added thermal burden resulting from work in PPE would shorten work time and result in a higher core temperature during incremental treadmill exercise. In this prospective, crossover, laboratory study, EMS providers (n = 8, 5 male) completed a Bruce treadmill test on two occasions: once in a chemical-resistant coverall and air-purifying respirator (PPE) and once in shorts and t-shirt (CON). Oxygen consumption, vital signs, core and skin temperature, and perceptual measures of exertion, thermal sensation, and comfort were monitored throughout the test. Subjects achieved maximal oxygen consumption and more than 90% of age-predicted maximum heart rate in both conditions. Heart rate, skin temperature, and measures of perceived exertion, comfort, and thermal sensation increased during the treadmill exercise but did not differ between the PPE and CON conditions. Core temperature increased in both the CON and PPE conditions (0.8 +/- 0.5 vs. 0.7 +/- 0.3, p = 0.40). High-intensity work in level C PPE is primarily limited by cardiovascular capacity. The thermal burden associated with this short bout of work in PPE (approximately 10 minutes) is not different than high-intensity work in short pants and cotton t-shirt. Consideration should be given to cardiorespiratory fitness when assigning providers to work in chemical-resistant PPE, especially on tasks that require high-intensity work.

Carnitine Acetyltransferase Mitigates Metabolic Inertia and Muscle Fatigue during Exercise.

PubMed

Seiler, Sarah E; Koves, Timothy R; Gooding, Jessica R; Wong, Kari E; Stevens, Robert D; Ilkayeva, Olga R; Wittmann, April H; DeBalsi, Karen L; Davies, Michael N; Lindeboom, Lucas; Schrauwen, Patrick; Schrauwen-Hinderling, Vera B; Muoio, Deborah M

2015-07-07

Acylcarnitine metabolites have gained attention as biomarkers of nutrient stress, but their physiological relevance and metabolic purpose remain poorly understood. Short-chain carnitine conjugates, including acetylcarnitine, derive from their corresponding acyl-CoA precursors via the action of carnitine acetyltransferase (CrAT), a bidirectional mitochondrial matrix enzyme. We show here that contractile activity reverses acetylcarnitine flux in muscle, from net production and efflux at rest to net uptake and consumption during exercise. Disruption of this switch in mice with muscle-specific CrAT deficiency resulted in acetyl-CoA deficit, perturbed energy charge, and diminished exercise tolerance, whereas acetylcarnitine supplementation produced opposite outcomes in a CrAT-dependent manner. Likewise, in exercise-trained compared to untrained humans, post-exercise phosphocreatine recovery rates were positively associated with CrAT activity and coincided with dramatic shifts in muscle acetylcarnitine dynamics. These findings show acetylcarnitine serves as a critical acetyl buffer for working muscles and provide insight into potential therapeutic strategies for combatting exercise intolerance. Copyright © 2015 Elsevier Inc. All rights reserved.

A study on the relationship between compulsive exercise, depression and anxiety

PubMed Central

Weinstein, Aviv; Maayan, Gavriel; Weinstein, Yitzhak

2015-01-01

Background and Aims Exercise and physical activity are beneficial both physically and psychologically but a few individuals use exercise excessively resulting in physical and even psychological damage. There is evidence for bi-directional relationship between exercise with depression and anxiety showing that exercise can reduce anxiety and depression, whereas a lack of exercise is associated with higher levels of anxiety and depression. Methods This study used questionnaires assessing compulsive exercise, anxiety and depression among 20 professional regular exercisers and 51 recreational regular exercisers. Results Results showed that ratings of compulsive exercise were associated with ratings of anxiety and depression among individuals who exercise for professional and recreational purpose. Secondly, individuals who exercise for professional purpose were more depressed than individuals who exercise for recreational purpose, but did not exhibit higher trait anxiety ratings. Thirdly, individuals who exercise for recreational purpose showed an association between ratings of compulsive exercise and depression but not with ratings of trait anxiety. Discussion Individuals who exercise for professional and recreational purpose may use it as a means for alleviating depression and anxiety although this small sample of recreational and professional sportsmen showed clinical levels of anxiety and depression that may require further clinical treatment. PMID:26690627

A study on the relationship between compulsive exercise, depression and anxiety.

PubMed

Weinstein, Aviv; Maayan, Gavriel; Weinstein, Yitzhak

2015-12-01

Exercise and physical activity are beneficial both physically and psychologically but a few individuals use exercise excessively resulting in physical and even psychological damage. There is evidence for bi-directional relationship between exercise with depression and anxiety showing that exercise can reduce anxiety and depression, whereas a lack of exercise is associated with higher levels of anxiety and depression. This study used questionnaires assessing compulsive exercise, anxiety and depression among 20 professional regular exercisers and 51 recreational regular exercisers. Results showed that ratings of compulsive exercise were associated with ratings of anxiety and depression among individuals who exercise for professional and recreational purpose. Secondly, individuals who exercise for professional purpose were more depressed than individuals who exercise for recreational purpose, but did not exhibit higher trait anxiety ratings. Thirdly, individuals who exercise for recreational purpose showed an association between ratings of compulsive exercise and depression but not with ratings of trait anxiety. Individuals who exercise for professional and recreational purpose may use it as a means for alleviating depression and anxiety although this small sample of recreational and professional sportsmen showed clinical levels of anxiety and depression that may require further clinical treatment.

South Asians have elevated postexercise blood pressure and myocardial oxygen consumption compared to Europeans despite equivalent resting pressure.

PubMed

Chaturvedi, Nish; Bathula, Rajaram; Shore, Angela C; Panerai, Ronney; Potter, John; Kooner, Jaspal; Chambers, John; Hughes, Alun D

2012-10-01

Stroke mortality rate is higher in South Asians than in Europeans, despite equivalent or lower resting blood pressure (BP). Elevated recovery BP after exercise predicts stroke, independently of resting values. We hypothesized that South Asians would have adverse postexercise hemodynamics and sought explanations for this. A population-based sample of 147 European and 145 South Asian middle-aged men and women performed the Dundee 3-minute step test. Cardiovascular risk factors were measured. BP, heart rate, and rate-pressure product, a measure of myocardial oxygen consumption, were compared. With 90% power and 5% significance, we could detect a difference of 0.38 of a standard deviation in any outcome measure. Resting systolic BP was similar in South Asians (144 mm Hg) and Europeans (142 mm Hg) (P=0.2), as was exercise BP (P=0.4). However, recovery systolic BP at 3 minutes after exercise was higher in South Asians by 4.3 mm Hg (95% confidence interval [CI], 0.2 to 8.3 mm Hg; P=0.04). This effect persisted when adjusted for exercise BP and work effort (5.4 mm Hg [95% CI, 2.2 to 8.7 mm Hg; P=0.001]). Adjustment for baroreflex insensitivity and greater aortic stiffness in South Asians contributes greatly to attenuating this ethnic difference (1.9 mm Hg [95% CI, -0.9 to 4.6 mm Hg; P=0.4]). Similarly, rate-pressure product recovery after exercise was impaired in South Asians by 735 mm Hg/min (95% CI, 137 to 1334 mm Hg/min; P=0.02); again, adjustment for baroreflex insensitivity and aortic stiffness attenuated this difference (261 mm Hg/min [95% CI, -39 to 561 mm Hg/min; P=0.3]). Postexercise recovery of BP and rate-pressure product is impaired in South Asians compared to Europeans even though resting and exercise BP are similar. This is associated with the autonomic dysfunction and aortic stiffness in South Asians.

The respiration pattern as an indicator of the anaerobic threshold.

PubMed

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

2015-08-01

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

Human thermoregulatory function during exercise and immersion after 35 days of horizontal bed-rest and recovery.

PubMed

Mekjavic, Igor B; Golja, Petra; Tipton, Michael J; Eiken, Ola

2005-10-01

The present study evaluated the effect of 35 days of experimental horizontal bed-rest on exercise and immersion thermoregulatory function. Fifteen healthy male volunteers were assigned to either a Control (n = 5) or Bed-rest (n = 10) group. Thermoregulatory function was evaluated during a 30-min bout of submaximal exercise on a cycle ergometer, followed immediately by a 100-min immersion in 28 degrees C water. For the Bed-rest group, exercise and immersion thermoregulatory responses observed post-bed-rest were compared with those after a 5 week supervised active recovery period. In both trials, the absolute work load during the exercise portion of the test was identical. During the exercise and immersion, we recorded skin temperature, rectal temperature, the difference in temperature between the forearm and third digit of the right hand (DeltaT(forearm-fingertip))--an index of skin blood flow, sweating rate from the forehead, oxygen uptake and heart rate at minute intervals. Subjects provided ratings of temperature perception and thermal comfort at 5-min intervals. Exercise thermoregulatory responses after bed-rest and recovery were similar. Subjective ratings of temperature perception and thermal comfort during immersion indicated that subjects perceived similar combinations of Tsk and Tre to be warmer and thermally less uncomfortable after bed-rest. The average (SD) exercise-induced increase in Tre relative to resting values was not significantly different between the Post-bed-rest (0.4 (0.2) degrees C) and Recovery (0.5 (0.2) degrees C) trials. During the post-exercise immersion, the decrease in Tre, relative to resting values, was significantly (P < 0.05) greater in the Post-bed-rest trial (0.9 (0.5) degrees C) than after recovery (0.4 (0.3) degrees C). DeltaT(forearm-fingertip) was 5.2 (0.9) degrees C and 5.8 (1.0) degrees C at the end of the post-bed-rest and recovery immersions, respectively. The gain of the shivering response (increase in VO(2) relative to the decrease in Tre; VO(2)/Tre) was 1.19 l min(-1) degrees C(-1) in the Recovery trial, and was significantly attenuated to 0.51 l min(-1) degrees C(-1) in the Post-bed-rest trial. The greater cooling rate observed in the post-bed-rest trial is attributed to the greater heat loss and reduced heat production. The former is the result of attenuated cold-induced vasoconstriction and enhanced sweating rate, and the latter a result of a lower shivering VO(2) response.

Hemodynamic responses to single sessions of aerobic exercise and resistance exercise in pregnancy.

PubMed

Petrov Fieril, Karolina; Glantz, Anna; Fagevik Olsen, Monika

2016-09-01

Previous research on maternal hemodynamic responses to a single exercise session during pregnancy is sparse, especially considering immediate responses to resistance exercise. The aim of the study was to examine blood pressure, heart rate, body temperature, and Rating of Perceived Exertion in healthy pregnant women during single sessions of continuous submaximal exercise in pregnancy week 21. A cross-over design was used. Twenty healthy pregnant women from four prenatal clinics in Gothenburg, Sweden, were included. On day 1, the women did 30 min of aerobic exercise and on day 3 they did 30 min of resistance exercise. Blood pressure, heart rate, and Rating of Perceived Exertion were measured after 15 and 30 min of exercise. After 15 and 30 min of exercise, there was a significant increase in systolic blood pressure and heart rate (p < 0.001). Diastolic blood pressure increased slightly more after 15 and 30 min of aerobic exercise (p = 0.01) than resistance exercise (p = 0.03). Resistance exercise was perceived as more intense than aerobic exercise after 15 min (p = 0.02) and 30 min (p = 0.001) of exercise. Five minutes after completing the exercise, blood pressure quickly reverted to normal although heart rate was still increased (p = 0.001). There was no correlation between heart rate and Rating of Perceived Exertion (rs  = 0.05-0.43). Maternal hemodynamic responses were essentially the same, regardless of whether the exercise was submaximal aerobic or resistance exercise, although resistance exercise was perceived as more intense. Aerobic and resistance exercise corresponding to "somewhat hard" seems to have no adverse effect with regard to maternal hemodynamic responses in healthy pregnancy. © 2016 Nordic Federation of Societies of Obstetrics and Gynecology.

Submaximal exercise with self-contained breathing apparatus: the effects of hyperoxia and inspired gas density.

PubMed

Eves, Neil D; Petersen, Stewart R; Jones, Richard L

2003-10-01

The self-contained breathing apparatus (SCBA) used by firefighters, and other working in dangerous environments, adds an external resistance to expiration, which increases expiratory work during heavy exercise. Compressed air is typically used with the SCBA and we hypothesized that changing the inspired oxygen concentration and/or gas density with helium would reduce the external expiratory resistance. On separate days, 15 men completed four 30-min bouts of treadmill exercise dressed in protective clothing and breathing the test gases through the SCBA. Four different gas mixtures were assigned in random order: [compressed air (NOX: 21% O2, 79% N2), hyperoxia (HOX: 40% O2, 60% N2), normoxic-helium (HE-OX: 21% O2, 79% He), and helium-hyperoxia (HE-HOX: 40% O2, 60% He)]. Compared with NOX, the two helium mixtures (but not HOX), decreased the external breathing resistance and all three gas mixtures decreased the peak expired mask pressure and the ventilatory mass moved. Both hyperoxic mixtures decreased blood lactate and the rating of perceived exertion was decreased at 30 min with HE-HOX. These results demonstrate that the helium-based gas mixtures, and to a lesser extent HOX, reduce the expiratory work associated with the SCBA during strenuous exercise.

Physical fitness and exercise training of individuals with mental retardation.

PubMed

Fernhall, B

1993-04-01

Recent social policies have focused on reentering persons with mental retardation (MR) into the work force and the mainstream of society. However, as individuals with MR age, their rate of institutionalization greatly outweighs that of the general population as well as children with MR. Health care organizations have expressed serious concern about the impact of an aging population with disabilities, particularly the cost associated with institutionalization. Considering that cardiovascular disorders are more common in population with than without MR, and that physical fitness has been directly related to work productivity among individuals with MR, physical fitness and exercise training have important implications for this population. Yet, available data suggest that individuals with MR have low levels of physical fitness, a higher incidence of obesity, and may respond differently to exercise training than persons without MR. This paper reviews current knowledge of physical fitness status, impact of exercise testing and training, and identifies differences between populations with and without MR, with special emphasis on trends associated with aging. This review is limited to three physical fitness components: obesity, cardiovascular fitness, and muscular strength and endurance, as these components have been shown to impact health and well-being, and are related to work performance of persons with MR. Suggestions for future research are also provided.

Energy expenditure and affect responses to different types of active video game and exercise.

PubMed

Monedero, Javier; Murphy, Enda E; O'Gorman, Donal J

2017-01-01

The purpose of this study was to compare entertainment-themed active video game (AVG) and fitness-themed AVG play with traditional exercise to examine the interaction between physiological and psychological responses. Participants (N = 23) were randomly assigned to 30-min of (i) self-selected intensity exercise (SS-EX), (ii) moderate intensity exercise (MOD-EX), (iii) entertainment-themed video game (ET-VG) and (iv) fitness-themed video game (FT-VG). Physiological and psychological outcomes were recorded before, during and after each trial. All trials met the ACSM criteria for moderate or vigorous physical activity. The [Formula: see text] (68.3±13.9%) and rate of energy expenditure (10.3±3.1kcal/min) was significantly higher in the SS-EX trial with lowest values reported for ET-VG (p<0.05). No differences were found in % heart rate reserve between SS-EX and FT-VG (66.9±12.5% and 67.1±6% respectively). The AVG's were significantly more enjoyable than the exercise trials (p<0.05) and the ET-VG resulted in the highest core flow and psychological well-being (p<0.05). AVG's can elicit physiological responses that meet recommended exercise intensities but are more enjoyable than conventional exercise in young inactive adults. While further work is required, this study highlights the importance of examining the interaction between physiological outcomes and psychological states to increase physical activity and reduce sedentary time.

Using exercises to improve public health preparedness in Asia, the Middle East and Africa

PubMed Central

2014-01-01

Background Exercises are increasingly common tools used by the health sector and other sectors to evaluate their preparedness to respond to public health threats. Exercises provide an opportunity for multiple sectors to practice, test and evaluate their response to all types of public health emergencies. The information from these exercises can be used to refine and improve preparedness plans. There is a growing body of literature about the use of exercises among local, state and federal public health agencies in the United States. There is much less information about the use of exercises among public health agencies in other countries and the use of exercises that involve multiple countries. Results We developed and conducted 12 exercises (four sub-national, five national, three sub-regional) from August 2006 through December 2008. These 12 exercises included 558 participants (average 47) and 137 observers (average 11) from 14 countries. Participants consistently rated the overall quality of the exercises as very good or excellent. They rated the exercises lowest on their ability to identifying key gaps in performance. The vast majority of participants noted that they would use the information they gained at the exercise to improve their organization’s preparedness to respond to an influenza pandemic. Participants felt the exercises were particularly good at raising awareness and understanding about public health threats, assisting in evaluating plans and identifying priorities for improvement, and building relationships that strengthen preparedness and response across sectors and across countries. Participants left the exercises with specific ideas about the most important actions that they should engage in after the exercise such as improved planning coordination across sectors and countries and better training of health workers and response personnel. Conclusions These experiences suggest that exercises can be a valuable, low-burden tool to improve emergency preparedness and response in countries around the world. They also demonstrate that countries can work together to develop and conduct successful exercises designed to improve regional preparedness to public health threats. The development of standardized evaluation methods for exercises may be an additional tool to help focus the actions to be taken as a result of the exercise and to improve future exercises. Exercises show great promise as tools to improve public health preparedness across sectors and countries. PMID:25063987

Exercise modality modulates body temperature regulation during exercise in uncompensable heat stress.

PubMed

Schlader, Zachary J; Raman, Aaron; Morton, R Hugh; Stannard, Stephen R; Mündel, Toby

2011-05-01

This study evaluated exercise modality [i.e. self-paced (SP) or fixed-intensity (FI) exercise] as a modulator of body temperature regulation under uncompensable heat stress. Eight well-trained male cyclists completed (work-matched) FI and SP cycling exercise bouts in a hot (40.6 ± 0.2°C) and dry (relative humidity 23 ± 3%) environment estimated to elicit 70% of [Formula: see text]O(2)max. Exercise intensity (i.e. power output) decreased over time in SP, which resulted in longer exercise duration (FI 20.3 ± 3.4 min, SP 23.2 ± 4.1 min). According to the heat strain index, the modification of exercise intensity in SP improved the compensability of the thermal environment which, relative to FI, was likely a result of the reductions in metabolic heat production (i.e. [Formula: see text]O(2)). Consequently, the rate of rise in core body temperature was higher in FI (0.108 ± 0.020°C/min) than in SP (0.082 ± 0.016°C/min). Interestingly, cardiac output, stroke volume, and heart rate during exercise were independent of exercise modality. However, core body temperature (FI 39.4 ± 0.3°C, SP 39.1 ± 0.4°C), blood lactate (FI 2.9 ± 0.8 mmol/L, SP 2.3 ± 0.7 mmol/L), perceived exertion (FI 18 ± 2, SP 16 ± 2), and physiological strain (FI 9.1 ± 0.9, SP 8.3 ± 1.1) were all higher in FI compared to SP at exhaustion/completion. These findings indicate that, when exercise is SP, behavioral modification of metabolic heat production improves the compensability of the thermal environment and reduces thermoregulatory strain. Therefore, under uncompensable heat stress, exercise modality modulates body temperature regulation.

Exercise promotes positive impression formation towards both men and women.

PubMed

Kanarek, Robin B; Mathes, Wendy Foulds; D'Anci, Kristen E

2012-06-01

Exercise is endorsed for its physiological and psychological benefits, and has been proposed to have positive effects on impression formation. To test this proposal, 62 female and 44 male college students read one of three brief descriptions of either a fictitious male or female "target" student. The descriptions varied only in exercise level: no exercise; moderate exercise and intensive exercise. Participants then rated the fictitious student on 38 personality traits. Ratings of characteristics that are associated with exercise (e.g. athletic; energetic) increased, while ratings associated with the lack of exercise (e.g. lazy; weak) decreased as a function of the reported level of exercise. Exercise level also positively influenced ratings of characteristics not related to exercise. These data show that even minimal information about exercise is an important component of first impressions in both men and women. Copyright © 2012 Elsevier Ltd. All rights reserved.

Randomized Controlled Trial Investigating the Role of Exercise in the Workplace to Improve Work Ability, Performance, and Patient-Reported Symptoms Among Older Workers With Osteoarthritis.

PubMed

Chopp-Hurley, Jaclyn N; Brenneman, Elora C; Wiebenga, Emily G; Bulbrook, Brittany; Keir, Peter J; Maly, Monica R

2017-06-01

The aim of this study was to evaluate the effectiveness of a 12-week workplace exercise program on work ability, performance, and patient-reported symptoms in older university employees with knee and/or hip osteoarthritis. Twenty-four participants with clinical hip and/or knee osteoarthritis were randomized to exercise or no exercise. At baseline and follow-up, several work (work ability, resilience), patient-reported (pain, physical function, depressive symptoms, self-efficacy), and performance outcomes (hip and knee strength, mobility performance) were measured. Significant improvements in work ability (P < 0.049) and patient-reported outcomes (pain, function, depressive symptoms) existed in the exercise group. No improvements were demonstrated in the no exercise group. Exercise in the workplace improved work ability and patient-reported symptoms in older workers with osteoarthritis. The benefits of workplace exercise programs should be studied in a larger sample in which attention is given to improving exercise adherence.

Temporal discounting rates and their relation to exercise behavior in older adults.

PubMed

Tate, Linda M; Tsai, Pao-Feng; Landes, Reid D; Rettiganti, Mallikarjuna; Lefler, Leanne L

2015-12-01

As our nation's population ages, the rates of chronic illness and disability are expected to increase significantly. Despite the knowledge that exercise may prevent chronic disease and promote health among older adults, many still are inactive. Factors related to exercise behaviors have been explored in recent years. However, temporal discounting is a motivational concept that has not been explored in regard to exercise in older adults. Temporal discounting is a decision making process by which an individual chooses a smaller more immediate reward over a larger delayed reward. The aim of this study was to determine if temporal discounting rates vary between exercising and non-exercising older adults. This study used cross-sectional survey of 137 older adults living in the community. Older adults were recruited from 11 rural Arkansas churches. The Kirby delay-discounting Monetary Choice Questionnaire was used to collect discounting rates and then bivariate analysis was performed to compare temporal discounting rate between the exercisers and non-exercisers. Finally, multivariate analysis was used to compare discounting rate controlling for other covariates. The results indicated that exercising older adults display lower temporal discounting rates than non-exercising older adults. After controlling for education, exercisers still have lower temporal discounting rates than non-exercisers (p<0.001). These findings are important as several chronic health conditions relate to lack of exercise especially in older adults. This research suggests that if we can find appropriate incentives for discounting individuals, some type of immediate reward, then potentially we can design programs to engage and retain older adults in exercise. Copyright © 2015 Elsevier Inc. All rights reserved.

The Effects of Metabolic Work Rate and Ambient Environment on Physiological Tolerance Times While Wearing Explosive and Chemical Personal Protective Equipment

PubMed Central

Costello, Joseph T.; Stewart, Kelly L.; Stewart, Ian B.

2015-01-01

This study evaluated the physiological tolerance times when wearing explosive and chemical (>35 kg) personal protective equipment (PPE) in simulated environmental extremes across a range of differing work intensities. Twelve healthy males undertook nine trials which involved walking on a treadmill at 2.5, 4, and 5.5 km·h−1 in the following environmental conditions, 21, 30, and 37°C wet bulb globe temperature (WBGT). Participants exercised for 60 min or until volitional fatigue, core temperature reached 39°C, or heart rate exceeded 90% of maximum. Tolerance time, core temperature, skin temperature, mean body temperature, heart rate, and body mass loss were measured. Exercise time was reduced in the higher WBGT environments (WBGT37 < WBGT30 < WBGT21; P < 0.05) and work intensities (5.5 < 4 < 2.5 km·h−1; P < 0.001). The majority of trials (85/108; 78.7%) were terminated due to participant's heart rate exceeding 90% of their maximum. A total of eight trials (7.4%) lasted the full duration. Only nine (8.3%) trials were terminated due to volitional fatigue and six (5.6%) due to core temperatures in excess of 39°C. These results demonstrate that physiological tolerance times are influenced by the external environment and workload and that cardiovascular strain is the limiting factor to work tolerance when wearing this heavy multilayered PPE. PMID:25866818

Left ventricular oxygen extraction during submaximal and maximal exertion in ponies.

PubMed Central

Manohar, M

1988-01-01

1. Left ventricular (LV) myocardial O2 extraction was studied in five healthy ponies which had catheters implanted in the great cardiac vein and main pulmonary artery 15-30 days before the study. The abdominal aorta was percutaneously catheterized to sample arterial blood. 2. In addition, phasic LV and aortic pressures, LV dP/dtmax and rate-pressure product were also studied; dP/dtmax is the maximal rate of rise of the left ventricular pressure during the isovolumic phase, and is considered an index of myocardial contractility. Measurements were made at rest (control) and during adenosine infusion (3 mumol kg-1 min-1) at rest, moderate exercise (heart rate 169 +/- 10 beats min-1), heavy exercise (heart rate 198 +/- 7 beats min-1), maximal exercise (heart rate 232 +/- 7 beats min-1), and adenosine infusion (3 mumol kg-1 min-1) during maximal exercise (heart rate 230 +/- 6 beats min-1). 3. In resting ponies, LV arterial to coronary venous O2 content difference (delta LVa-v O2) was 8.9 +/- 0.5 ml dl-1 and O2 extraction was 59.9 +/- 2.2%. Adenosine infusion at rest decreased delta LVa-v O2 and O2 extraction precipitously (2.6 ml dl-1 and 14.3 +/- 1.7%, respectively), thereby indicating superfluous LV myocardial perfusion. 4. Moderate, heavy and maximal exercise increased delta LVa-v O2 to 185, 194 and 218% of its control value and O2 extraction rose to 71 +/- 2, 75 +/- 1.5 and 78 +/- 0.9%, respectively. The widening of the delta LVa-v O2 gradient was due to the increased arterial O2 content during exercise. 5. Combining these observations with equine myocardial perfusion, the LV O2 consumption was calculated to be 7.8, 47.9 and 103.6 ml min-1 100 g-1 at rest, moderate and maximal exercise. In order to achieve the 13.4-fold increase in LV O2 consumption, the LV perfusion rose only 6-fold; the rest being met by widening the delta LVa-v O2. 6. Adenosine infusion during maximal exercise decreased delta LVa-v O2 and O2 extraction (10.7 +/- 1 ml dl-1 and 45%, respectively; P less than 0.0001). This indicated that coronary vasodilator capacity was not being completely expended in maximally exercising ponies. It is concluded that coronary circulation is unlikely to be a limiting factor to further exertion in ponies. Organ/tissue perfusion studies in exercising ponies have demonstrated that of all working muscles, the left ventricular (LV) myocardium received the highest level of blood flow.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:3150987

Evidence for metaboreceptor stimulation of sweating in normothermic and heat-stressed humans

NASA Technical Reports Server (NTRS)

Shibasaki, M.; Kondo, N.; Crandall, C. G.

2001-01-01

1. Isometric handgrip (IHG) exercise increases sweat rate and arterial blood pressure, and both remain elevated during post-exercise ischaemia. The purpose of this study was to identify whether the elevation in arterial blood pressure during post-exercise ischaemia contributes to the increase in sweating. 2. In normothermia and during whole-body heating, 2 min IHG exercise at 40% maximal voluntary contraction, followed by 2 min post-exercise ischaemia, was performed with and without bolus intravenous administration of sodium nitroprusside during the ischaemic period. Sodium nitroprusside was administered to reduce blood pressure during post-exercise ischaemia to pre-exercise levels. Sweat rate was monitored over two microdialysis membranes placed in the dermal space of forearm skin. One membrane was perfused with the acetylcholinesterase inhibitor neostigmine, while the other was perfused with the vehicle. 3. In normothermia, IHG exercise increased sweat rate at the neostigmine-treated site but not at the control site. Sweat rate remained elevated during post-exercise ischaemia even after mean arterial blood pressure returned to the pre-IHG exercise baseline. Subsequent removal of the ischaemia stimulus returned sweat rate to pre-IHG exercise levels. Sweat rate during post-exercise ischaemia without sodium nitroprusside administration followed a similar pattern. 4. During whole-body heating, IHG exercise increased sweat rate at both neostigmine-treated and untreated sites. Similarly, regardless of whether mean arterial blood pressure remained elevated or was reduced during post-exercise ischaemia, sweat rate remained elevated during the ischaemic period. 5. These results suggest that sweating in non-glabrous skin during post-IHG exercise ischaemia is activated by metaboreflex stimulation and not via baroreceptor loading.

Pendulum Exercises After Hip Arthroscopy: A Video Technique.

PubMed

Sauber, Ryan; Saborio, George; Nickel, Beth M; Kivlan, Benjamin R; Christoforetti, John J

2016-08-01

Advanced hip joint-preserving arthroscopic techniques have been shown to improve patient-reported functional outcomes with low rates of postoperative complications. Prior work has shown that formation of adhesive scar is a potential source of persistent pain and cause for revision surgery. As resources for postoperative in-studio physical therapy become scarce, a home-based strategy to avoid scar formation without adding formal therapy cost may be beneficial. The purpose of this technical note is to introduce a patient-centered educational video technique for home-caregiver delivery of manual hip pendulum exercises in the postoperative setting. This video technique offers access to our method for pendulum exercise as part of early recovery after advanced hip arthroscopy.

Occupational stress, relaxation therapies, exercise and biofeedback.

PubMed

Stein, Franklin

2001-01-01

Occupational stress is a widespread occurrence in the United States. It is a contributing factor to absenteeism, disease, injury and lowered productivity. In general stress management programs in the work place that include relaxation therapies, exercise, and biofeedback have been shown to reduce the physiological symptoms such as hypertension, and increase job satisfaction and job performance. Strategies to implement a successful stress management program include incorporating the coping activities into one's daily schedule, monitoring one's symptoms and stressors, and being realistic in setting up a schedule that is relevant and attainable. A short form of meditation, daily exercise program and the use of heart rate or thermal biofeedback can be helpful to a worker experiencing occupational stress.

The Exercise–Affect–Adherence Pathway: An Evolutionary Perspective

PubMed Central

Lee, Harold H.; Emerson, Jessica A.; Williams, David M.

2016-01-01

The low rates of regular exercise and overall physical activity (PA) in the general population represent a significant public health challenge. Previous research suggests that, for many people, exercise leads to a negative affective response and, in turn, reduced likelihood of future exercise. The purpose of this paper is to examine this exercise–affect–adherence relationship from an evolutionary perspective. Specifically, we argue that low rates of physical exercise in the general population are a function of the evolved human tendency to avoid unnecessary physical exertion. This innate tendency evolved because it allowed our evolutionary ancestors to conserve energy for physical activities that had immediate adaptive utility such as pursuing prey, escaping predators, and engaging in social and reproductive behaviors. The commonly observed negative affective response to exercise is an evolved proximate psychological mechanism through which humans avoid unnecessary energy expenditure. The fact that the human tendencies toward negative affective response to and avoidance of unnecessary physical activities are innate does not mean that they are unchangeable. Indeed, it is only because of human-engineered changes in our environmental conditions (i.e., it is no longer necessary for us to work for our food) that our predisposition to avoid unnecessary physical exertion has become a liability. Thus, it is well within our capabilities to reengineer our environments to once again make PA necessary or, at least, to serve an immediate functional purpose. We propose a two-pronged approach to PA promotion based on this evolutionary functional perspective: first, to promote exercise and other physical activities that are perceived to have an immediate purpose, and second, to instill greater perceived purpose for a wider range of physical activities. We posit that these strategies are more likely to result in more positive (or less negative) affective responses to exercise, better adherence to exercise programs, and higher rates of overall PA. PMID:27610096

Restoration of plasma volume after 16 days of head-down tilt induced by a single bout of maximal exercise

NASA Technical Reports Server (NTRS)

Convertino, V. A.; Engelke, K. A.; Ludwig, D. A.; Doerr, D. F.

1996-01-01

Seven healthy men performed maximal exercise 24 h before the end of 16 days exposure to 6 degrees head-down tilt (HDT) to test the hypothesis that such an exercise technique could restore plasma volume (PV) at the end of a simulated space mission. Exercise consisted of supine cycling with graded work rates increasing by 16 W/min to volitional fatigue and required an average of 16 min. The experimental protocol was a standard cross-over design in which the order of treatment (exercise or control) was counterbalanced across all seven subjects. PV, fluid intake (ad libitum), urine output, renal function, and hormones associated with fluid homeostasis were measured before HDT, 24 h before the end of HDT just prior to exercise, and at the end of HDT 24 h after exercise. HDT reduced PV by 16% in both control and exercise conditions. Maximal exercise completely restored plasma volume within 24 h to 3.9 +/- 3.2% of pre-HDT levels despite continued HDT. Compared with control, exercise induced a 660-ml larger positive fluid balance because of greater fluid intake and reduced urine volume during the 24 h after exercise. These results suggest that one bout of maximal leg exercise before return from 16 days of spaceflight may be completely effective in stimulating thirst and restoring plasma volume to preflight levels.

The 'Critical Power' Concept: Applications to Sports Performance with a Focus on Intermittent High-Intensity Exercise.

PubMed

Jones, Andrew M; Vanhatalo, Anni

2017-03-01

The curvilinear relationship between power output and the time for which it can be sustained is a fundamental and well-known feature of high-intensity exercise performance. This relationship 'levels off' at a 'critical power' (CP) that separates power outputs that can be sustained with stable values of, for example, muscle phosphocreatine, blood lactate, and pulmonary oxygen uptake ([Formula: see text]), from power outputs where these variables change continuously with time until their respective minimum and maximum values are reached and exercise intolerance occurs. The amount of work that can be done during exercise above CP (the so-called W') is constant but may be utilized at different rates depending on the proximity of the exercise power output to CP. Traditionally, this two-parameter CP model has been employed to provide insights into physiological responses, fatigue mechanisms, and performance capacity during continuous constant power output exercise in discrete exercise intensity domains. However, many team sports (e.g., basketball, football, hockey, rugby) involve frequent changes in exercise intensity and, even in endurance sports (e.g., cycling, running), intensity may vary considerably with environmental/course conditions and pacing strategy. In recent years, the appeal of the CP concept has been broadened through its application to intermittent high-intensity exercise. With the assumptions that W' is utilized during work intervals above CP and reconstituted during recovery intervals below CP, it can be shown that performance during intermittent exercise is related to four factors: the intensity and duration of the work intervals and the intensity and duration of the recovery intervals. However, while the utilization of W' may be assumed to be linear, studies indicate that the reconstitution of W' may be curvilinear with kinetics that are highly variable between individuals. This has led to the development of a new CP model for intermittent exercise in which the balance of W' remaining ([Formula: see text]) may be calculated with greater accuracy. Field trials of athletes performing stochastic exercise indicate that this [Formula: see text] model can accurately predict the time at which W' tends to zero and exhaustion is imminent. The [Formula: see text] model potentially has important applications in the real-time monitoring of athlete fatigue progression in endurance and team sports, which may inform tactics and influence pacing strategy.

Orbital Fitness: An Overview of Space Shuttle Cardiopulmonary Exercise Physiology Findings

NASA Technical Reports Server (NTRS)

Moore, Alan D.

2011-01-01

Limited observations regarding the cardiopulmonary responses to aerobic exercise had been conducted during short-duration spaceflight before the Space Shuttle program. This presentation focuses on the findings regarding changes observed in the cardiopulmonary exercise responses during and following Shuttle flights. During flight, maximum oxygen uptake (VO2max) remained unchanged as did the maximum work rate achievable during cycle exercise testing conducted during the last full flight day. Immediately following flight, the ubiquitous finding, confirmed by investigations conducted during the Spacelab Life Sciences missions 1 and 2 and by NASA Detailed Supplemental Objective studies, indicated that VO2max was reduced; however, the reduction in VO2max was transient and returned to preflight levels within 7 days following return. Studies regarding the influence of aerobic exercise countermeasures performed during flight on postflight performance were mostly limited to the examination of the heart rate (HR) response to submaximal exercise testing on landing day. These studies revealed that exercise HR was elevated in individuals who performed little to no exercise during their missions as compared to individuals who performed regular exercise. In addition, astronauts who performed little to no aerobic exercise during flight demonstrated an increased HR and lowered pulse pressure response to the standard stand test on landing day, indicating a decrease in orthostatic function in these individuals. With regard to exercise modality, four devices were examined during the Shuttle era: two treadmills, a cycle ergometer, and a rowing device. Although there were limited investigations regarding the use of these devices for exercise training aboard the Shuttle, there was no clear consensus reached regarding which proved to be a "superior" device. Each device had a unique operational or physiologic limitation associated with its use. In conclusion, exercise research conducted during the Shuttle Program demonstrated that attenuation of postflight deconditioning was possible through use of exercise countermeasures and the Shuttle served as a test bed for equipment destined for use on the International Space Station. Learning Objective: Overview of the Space Shuttle Program research results related to aerobic capacity and performance, including what was learned from research and effectiveness of exercise countermeasures.

Music in the exercise domain: a review and synthesis (Part I)

PubMed Central

Karageorghis, Costas I.; Priest, David-Lee

2011-01-01

Since a 1997 review by Karageorghis and Terry, which highlighted the state of knowledge and methodological weaknesses, the number of studies investigating musical reactivity in relation to exercise has swelled considerably. In this two-part review paper, the development of conceptual approaches and mechanisms underlying the effects of music are explicated (Part I), followed by a critical review and synthesis of empirical work (spread over Parts I and II). Pre-task music has been shown to optimise arousal, facilitate task-relevant imagery and improve performance in simple motoric tasks. During repetitive, endurance-type activities, self-selected, motivational and stimulative music has been shown to enhance affect, reduce ratings of perceived exertion, improve energy efficiency and lead to increased work output. There is evidence to suggest that carefully selected music can promote ergogenic and psychological benefits during high-intensity exercise, although it appears to be ineffective in reducing perceptions of exertion beyond the anaerobic threshold. The effects of music appear to be at their most potent when it is used to accompany self-paced exercise or in externally valid conditions. When selected according to its motivational qualities, the positive impact of music on both psychological state and performance is magnified. Guidelines are provided for future research and exercise practitioners. PMID:22577472

Music in the exercise domain: a review and synthesis (Part II)

PubMed Central

Karageorghis, Costas I.; Priest, David-Lee

2011-01-01

Since a 1997 review by Karageorghis and Terry, which highlighted the state of knowledge and methodological weaknesses, the number of studies investigating musical reactivity in relation to exercise has swelled considerably. In this two-part review paper, the development of conceptual approaches and mechanisms underlying the effects of music are explicated (Part I), followed by a critical review and synthesis of empirical work (spread over Parts I and II). Pre-task music has been shown to optimise arousal, facilitate task-relevant imagery and improve performance in simple motoric tasks. During repetitive, endurance-type activities, self-selected, motivational and stimulative music has been shown to enhance affect, reduce ratings of perceived exertion, improve energy efficiency and lead to increased work output. There is evidence to suggest that carefully selected music can promote ergogenic and psychological benefits during high-intensity exercise, although it appears to be ineffective in reducing perceptions of exertion beyond the anaerobic threshold. The effects of music appear to be at their most potent when it is used to accompany self-paced exercise or in externally valid conditions. When selected according to its motivational qualities, the positive impact of music on both psychological state and performance is magnified. Guidelines are provided for future research and exercise practitioners. PMID:22577473

Enzymatic capacities of skeletal muscle - Effects of different types of training

NASA Technical Reports Server (NTRS)

Booth, F. W.; Hugman, G. R.

1981-01-01

Long-term adaptation mechanisms to maintain homeostasis at increased levels of exertion such as those caused by regular exercise are described. Mitochondrial changes have been found to be a result of endurance exercises, while mitochondrial responses to other types of exercise are small. Further discussion is devoted to long-term changes in glucose transport, hexokinase, phosphofructokinase, pyruvate kinase, and the increased sensitivity of an endurance trained muscle to insulin. Less lactate has been found to be produced by the skeletal muscles at the same work rate after adaptation to endurance exercise training, and the capacity for the flux of the two-carbon acetyl chain through the citric acid cycle increases in skeletal muscles in response to endurance training. Finally, endurance training is noted to result in glycogen sparing and an increase in the capacity to utilize fatty acids.

A comparison of head motion and prefrontal haemodynamics during upright and recumbent cycling exercise.

PubMed

Tempest, Gavin D; Eston, Roger G; Parfitt, Gaynor

2017-11-01

The aim of this observational study was to compare head motion and prefrontal haemodynamics during exercise using three commercial cycling ergometers. Participants (n = 12) completed an incremental exercise test to exhaustion during upright, recumbent and semi-recumbent cycling. Head motion (using accelerometry), physiological data (oxygen uptake, end-tidal carbon dioxide [P ET CO 2 ] and heart rate) and changes in prefrontal haemodynamics (oxygenation, deoxygenation and blood volume using near infrared spectroscopy [NIRS]) were recorded. Despite no difference in oxygen uptake and heart rate, head motion was higher and P ET CO 2 was lower during upright cycling at maximal exercise (P<0·05). Analyses of covariance (covariates: head motion P>0·05; P ET CO 2 , P<0·01) revealed that prefrontal oxygenation was higher during semi-recumbent than recumbent cycling and deoxygenation and blood volume were higher during upright than recumbent and semi-recumbent cycling (respectively; P<0·05). This work highlights the robustness of the utility of NIRS to head motion and describes the potential postural effects upon the prefrontal haemodynamic response during upright and recumbent cycling exercise. © 2016 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

Anaerobic work calculated in cycling time trials of different length.

PubMed

Mulder, Roy C; Noordhof, Dionne A; Malterer, Katherine R; Foster, Carl; de Koning, Jos J

2015-03-01

Previous research showed that gross efficiency (GE) declines during exercise and therefore influences the expenditure of anaerobic and aerobic resources. To calculate the anaerobic work produced during cycling time trials of different length, with and without a GE correction. Anaerobic work was calculated in 18 trained competitive cyclists during 4 time trials (500, 1000, 2000, and 4000-m). Two additional time trials (1000 and 4000 m) that were stopped at 50% of the corresponding "full" time trial were performed to study the rate of the decline in GE. Correcting for a declining GE during time-trial exercise resulted in a significant (P<.001) increase in anaerobically attributable work of 30%, with a 95% confidence interval of [25%, 36%]. A significant interaction effect between calculation method (constant GE, declining GE) and distance (500, 1000, 2000, 4000 m) was found (P<.001). Further analysis revealed that the constant-GE calculation method was different from the declining method for all distances and that anaerobic work calculated assuming a constant GE did not result in equal values for anaerobic work calculated over different time-trial distances (P<.001). However, correcting for a declining GE resulted in a constant value for anaerobically attributable work (P=.18). Anaerobic work calculated during short time trials (<4000 m) with a correction for a declining GE is increased by 30% [25%, 36%] and may represent anaerobic energy contributions during high-intensity exercise better than calculating anaerobic work assuming a constant GE.

The influence of incline and speed on work rate, gross efficiency and kinematics of roller ski skating.

PubMed

Sandbakk, Øyvind; Ettema, Gertjan; Holmberg, Hans-Christer

2012-08-01

During competitions, elite cross-country skiers produce higher external work rates on uphill than on flat terrain. However, it is not presently known whether this reflects solely higher energy expenditure. Furthermore, the kinematic factors associated with these higher rates of uphill work have not yet been examined. Therefore, in the present investigation the work rate and associated kinematic parameters at similar metabolic rates during roller ski skating on flat and uphill terrains have been compared. Seven elite male skiers performed six 5-min sub-maximal exercise bouts at the same low, moderate and high metabolic rates on 2 and 8% inclines, while roller skiing on a treadmill employing the G3 skating technique. The work rate was calculated as work against gravity and friction, whereas the energetic equivalent of VO(2) was taken as the metabolic rate. Gross efficiency was defined as work rate divided by metabolic rate. Kinematic parameters were analyzed in three dimensions. At the same metabolic rate, the work rate, cycle rate, work per cycle and relative duration of propulsive phases during a cycle of movement were all higher on the 8% than on the 2% incline at all speeds (all P < 0.05). At similar work rates, gross efficiency was greater on the 8% incline (P < 0.05). In conclusion, these elite skiers consistently demonstrated higher work rates on the 8% incline. To achieve the higher work rates on the steeper incline, these elite skiers employed higher cycle rates and performed more work per cycle, in association with a longer relative propulsive phase.

Energy expenditure for massage therapists during performing selected classical massage techniques.

PubMed

Więcek, Magdalena; Szymura, Jadwiga; Maciejczyk, Marcin; Szyguła, Zbigniew; Cempla, Jerzy; Borkowski, Mateusz

2018-04-11

The aim of the study is to evaluate the intensity of the effort and energy expenditure in the course of performing selected classical massage techniques and to assess the workload of a massage therapist during a work shift. Thirteen massage therapists (age: 21.9±1.9 years old, body mass index: 24.5±2.8 kg×m^-2, maximal oxygen consumption × body mass^-1 (VO_{2 max}×BM^-1): 42.3±7 ml×kg^-1×min^-1) were involved in the study. The stress test consisted in performing selected classical massage techniques in the following order: stroking, kneading, shaking, beating, rubbing and direct vibration, during which the cardio-respiratory responses and the subjective rating of perceived exertion (RPE) were assessed. Intensity of exercise during each massage technique was expressed as % VO_{2 max}, % maximal heart rate (HR_max) and % heart rate reserve (HRR). During each massage technique, net energy expenditure (EE) and energy cost of work using metabolic equivalent of task (MET) were determined. The intensity of exercise was 47.2±6.2% as expressed in terms of % VO_{2 max}, and 74.7±3.2% as expressed in terms of % HR_max, while it was 47.8±1.7% on average when expressed in terms of % HRR during the whole procedure. While performing the classical massage, the average EE and MET were 5.6±0.9 kcal×min^-1 and 5.6±0.2, respectively. The average RPE calculated for the entire procedure was 12.1±1.4. During the performance of a classical massage technique for a single treatment during the study, the average total EE was 176.5±29.6 kcal, resulting in an energy expenditure of 336.2±56.4 kcal×h^-1. In the case of the classical massage technique, rubbing was the highest intensity exercise for the masseur who performed the massage (%VO_{2 max} = 57.4±13.1%, HR_max = 79.6±7.7%, HRR = 58.5±13.1%, MET = 6.7±1.1, EE = 7.1±1.4 kcal×min^-1, RPE = 13.4±1.3). In the objective assessment, physical exercise while performing a single classical massage is characterized by hard work. The technique of classical massage during which the masseur performs the highest exercise intensity is rubbing. According to the classification of work intensity based on energy expenditure, the masseur's work is considered heavy during the whole work shift. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

[Leisure-time sport activities and cardiac outpatient therapy in coronary patients].

PubMed

Heitkamp, Hans-Christian; Schimpf, Thomas M; Hipp, Arno; Niess, Andreas

2005-03-01

Exercise intensity in coronary patients is controlled by heart rate measurements. Very few investigations have compared the maximum heart rate in cardiac outpatient groups, in leisure-time sport activities, and especially in swimming. Within different exercise conditions 21 coronary patients, nine in well-compensated cardiac condition joining a training group and twelve joining the exercise group with lower intensity, without signs of heart failure, engaged in an incremental bicycle ergometry. A six-lead ECG was derived at the same time with a 24-h ECG. The performance tolerance was measured by the pulse limit derived in 20 patients; one patient failed to show signs of subjective or objective ischemia. During a 24-h ECG monitoring, the patients took part in a 1-h standardized cardiac outpatient program, a standardized swimming program 4 x 25 m, and a typical self-selected leisure-time activity. The patients showed a peak work capacity of 2.2 W/kg and a symptom-free work capacity of 1.3 W/kg. The derived upper heart rate limit was passed during swimming by 19, during leisure-time activity by 16, and during cardiac outpatient program by two patients. The maximum of the mean overriding the limit occurred in leisure-time activity. Signs of ischemia occurred during ergometry in 15, during swimming training in ten patients, during leisure-time activity in eight, and during cardiac outpatient therapy in one. Arrhythmia < Lown IVa was documented on the ergometer in 15, during leisure-time sport activity in 15, during cardiac outpatient therapy in 17, and during swimming in eight patients. Arrhythmia Lown IVa occurred in one patient each during ergometry, leisure sports, and during the night. Coronary patients are in danger to exercise beyond the pulse limit during swimming and other leisure-time sports and not during cardiac outpatient therapy. The upper heart rate limit should be observed during swimming and other endurance leisure-time activities, and is of little importance during cardiac outpatient therapy.

Facilitators and barriers to exercise adherence in patients with osteopenia and osteoporosis: a systematic review.

PubMed

Rodrigues, I B; Armstrong, J J; Adachi, J D; MacDermid, J C

2017-03-01

The aim of this study was to categorize the facilitators and barriers of exercise and identify methods to promote exercise adherence in the osteoporosis population. Despite the fair methodological quality of included randomized controlled trials (RCTs), less than 75 % identified facilitators and barriers to exercise. Methods to promote and measure exercise adherence were poorly reported. Several studies have shown exercise to be successful in maintaining or increasing BMD in individuals with low bone mass. Yet, adherence to exercise is poor, with 50 % of those registered in an exercise program dropping out within the first 6 months, lack of time being the number one barrier in many populations. However, in the osteoporosis population, the main facilitator and barrier to exercise is still unclear. The aim of this study is to examine the extent to which RCTs reported the facilitators and the barriers to exercise and identified methods to promote adherence to an exercise program. PubMed, CINHAL, EMBASE, and the Cochrane Review were queried using a predefined search criterion, and the resulting citations were imported into DistillerSR. Screening was carried out by two independent reviewers, and articles were included in the analysis by consensus. The methodological quality of included studies was assessed using the PEDro scale. Fifty-four RCTs examining exercise interventions in patients with osteopenia or osteoporosis were included. A spectrum of facilitators and barriers to exercise for osteoporotic patients were identified; however, no one facilitator was more frequently reported than the other. The most commonly reported barriers were lack of time and transportation. In most RCTs, methods to promote and measure exercise adherence were unsatisfactory. Of the 54 papers, 72 % reported an adherence rate to an exercise program; the lowest reported rate was 51.7 %, and the highest 100 %. Most RCTs found were of fair quality; however, less than three quarters identified facilitators and barriers to exercise. Reporting of methods to promote and measure exercise adherence were low. Future work should be directed toward identifying major facilitators and barriers to exercise adherence within RCTs. Only then can methods be identified to leverage facilitators and overcome barriers, thus strengthening the evidence for efficacy of optimal interventional exercise programs. This review has been registered in PROSPERO under registration number CRD42016039941.

Metoprolol vs ivabradine in patients with mitral stenosis in sinus rhythm.

PubMed

Agrawal, Vikas; Kumar, Niraj; Lohiya, Balalji; Sihag, Bhupendra K; Prajapati, Rajpal; Singh, T B; Subramanian, Geetha

2016-10-15

Severe mitral stenosis is usually symptomatic and is treated by BMV or surgery, whereas mild to moderate mitral stenosis is usually asymptomatic or mildly symptomatic and managed medically. Patients in the later group may become symptomatic during episodes of exercise and increased heart rate. Beta-blockers are frequently used in patients with mitral stenosis to control the heart rate and alleviate exercise-related symptoms. The objective of our study was to investigate the comparative efficacy of ivabradine versus metoprolol in patients with mitral stenosis in sinus rhythm. We studied 97 patients of mitral stenosis in sinus rhythm presented with exertional symptoms. The effectiveness of Metoprolol was compared with ivabradine in alleviating these exertional symptoms in a randomized, open label non crossover study. We also assessed various stress ECG parameters, 24 hour Holter parameters and 2D Echo parameters to objectively compare the effects of ivabradine and metoprolol in these patients. Ivabradine and metoprolol both were effective in controlling exertional symptoms. Significant improvement in objective parameters like TMT (work capacity, baseline heart rate and maximal heart rate) and 2D echocardiography (right ventricular systolic pressure) are seen with both drugs. Ivabradine controls the exertional symptoms significantly more than metoprolol. On head to head comparison there was a significant benefit of working capacity and heart rate at maximal exercise in favour of ivabradine. Ivabradine should be strongly considered in medical management of mitral stenosis patients where beta blockers are contraindicated such as reactive airway disease. The cost of ivabradine is higher than metoprolol which might possess constraints as most of the rheumatic heat disease patients belong to low socio economic status. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Effects of normoxic and hypoxic exercise regimens on monocyte-mediated thrombin generation in sedentary men.

PubMed

Wang, Jong-Shyan; Chang, Ya-Lun; Chen, Yi-Ching; Tsai, Hsing-Hua; Fu, Tieh-Cheng

2015-08-01

Exercise and hypoxia paradoxically modulate vascular thrombotic risks. The shedding of procoagulant-rich microparticles from monocytes may accelerate the pathogenesis of atherothrombosis. The present study explores the manner in which normoxic and hypoxic exercise regimens affect procoagulant monocyte-derived microparticle (MDMP) formation and monocyte-promoted thrombin generation (TG). Forty sedentary healthy males were randomized to perform either normoxic (NET; 21% O2, n=20) or hypoxic (HET; 15% O2, n=20) exercise training (60% VO(2max)) for 30 min/day, 5 days/week for 5 weeks. At rest and immediately after HET (100 W under 12% O2 for 30 min), the MDMP characteristics and dynamic TG were measured by flow cytometry and thrombinography respectively. The results demonstrated that acute 12% O2 exercise (i) increased the release of coagulant factor V (FV)/FVIII-rich, phosphatidylserine (PS)-exposed and tissue factor (TF)-expressed microparticles from monocytes, (ii) enhanced the peak height and rate of TG in monocyte-rich plasma (MRP) and (iii) elevated concentrations of norepinephrine/epinephrine, myeloperoxidase (MPO) and interleukin-6 (IL-6) in plasma. Following the 5-week intervention, HET exhibited higher enhancements of peak work-rate and cardiopulmonary fitness than NET did. Moreover, both NET and HET decreased the FV/FVIII-rich, PS-exposed and TF-expressed MDMP counts and the peak height and rate of TG in MRP following the HET. However, HET elicited more suppression for the HE (hypoxic exercise)-enhanced procoagulant MDMP formation and dynamic TG in MPR and catecholamine/peroxide/pro-inflammatory cytokine levels in plasma than NET. Hence, we conclude that HET is superior to NET for enhancing aerobic capacity. Furthermore, HET effectively suppresses procoagulant MDMP formation and monocyte-mediated TG under severe hypoxic stress, compared with NET.

Circadian variation in sports performance.

PubMed

Atkinson, G; Reilly, T

1996-04-01

Chronobiology is the science concerned with investigations of time-dependent changes in physiological variables. Circadian rhythms refer to variations that recur every 24 hours. Many physiological circadian rhythms at rest are endogenously controlled, and persist when an individual is isolated from environmental fluctuations. Unlike physiological variables, human performance cannot be monitored continuously in order to describe circadian rhythmicity. Experimental studies of the effect of circadian rhythms on performance need to be carefully designed in order to control for serial fatigue effects and to minimise disturbances in sleep. The detection of rhythmicity in performance variables is also highly influenced by the degree of test-retest repeatability of the measuring equipment. The majority of components of sports performance, e.g. flexibility, muscle strength, short term high power output, vary with time of day in a sinusoidal manner and peak in the early evening close to the daily maximum in body temperature. Psychological tests of short term memory, heart rate-based tests of physical fitness, and prolonged submaximal exercise performance carried out in hot conditions show peak times in the morning. Heart rate-based tests of work capacity appear to peak in the morning because the heart rate responses to exercise are minimal at this time of day. Post-lunch declines are evident with performance variables such as muscle strength, especially if measured frequently enough and sequentially within a 24-hour period to cause fatigue in individuals. More research work is needed to ascertain whether performance in tasks demanding fine motor control varies with time of day. Metabolic and respiratory rhythms are flattened when exercise becomes strenuous whilst the body temperature rhythm persists during maximal exercise. Higher work-rates are selected spontaneously in the early evening. At present, it is not known whether time of day influences the responses of a set training regimen (one in which the training stimulus does not vary with time of day) for endurance, strength, or the learning of motor skills. The normal circadian rhythms can be desynchronised following a flight across several time zones or a transfer to nocturnal work shifts. Although athletes show all the symptoms of 'jet lag' (increased fatigue, disturbed sleep and circadian rhythms), more research work is needed to identify the effects of transmeridian travel on the actual performances of elite sports competitors. Such investigations would need to be chronobiological, i.e. monitor performance at several times on several post-flight days, and take into account direction of travel, time of day of competition and the various performance components involved in a particular sport. Shiftwork interferes with participation in competitive sport, although there may be greater opportunities for shiftworkers to train in the hours of daylight for individual sports such as cycling and swimming. Studies should be conducted to ascertain whether shiftwork-mediated rhythm disturbances affect sports performance. Individual differences in performance rhythms are small but significant. Circadian rhythms are larger in amplitude in physically fit individuals than sedentary individuals. Athletes over 50 years of age tend to be higher in 'morningness', habitually scheduling relatively more training in the morning and selecting relatively higher work-rates during exercise compared with young athletes. These differences should be recognised by practitioners concerned with organising the habitual regimens of athletes.

A computerized recognition system for the home-based physiotherapy exercises using an RGBD camera.

PubMed

Ar, Ilktan; Akgul, Yusuf Sinan

2014-11-01

Computerized recognition of the home based physiotherapy exercises has many benefits and it has attracted considerable interest among the computer vision community. However, most methods in the literature view this task as a special case of motion recognition. In contrast, we propose to employ the three main components of a physiotherapy exercise (the motion patterns, the stance knowledge, and the exercise object) as different recognition tasks and embed them separately into the recognition system. The low level information about each component is gathered using machine learning methods. Then, we use a generative Bayesian network to recognize the exercise types by combining the information from these sources at an abstract level, which takes the advantage of domain knowledge for a more robust system. Finally, a novel postprocessing step is employed to estimate the exercise repetitions counts. The performance evaluation of the system is conducted with a new dataset which contains RGB (red, green, and blue) and depth videos of home-based exercise sessions for commonly applied shoulder and knee exercises. The proposed system works without any body-part segmentation, bodypart tracking, joint detection, and temporal segmentation methods. In the end, favorable exercise recognition rates and encouraging results on the estimation of repetition counts are obtained.

The relationship between heart rate recovery and brain natruretic Peptide in patients with chest discomfort: a study for relationship between heart rate recovery and pre-exercise, post-exercise levels of brain natruretic Peptide in patients with normal systolic function and chest discomfort.

PubMed

Lee, Jae Eun; Kim, Bum Soo; Park, Wan; Huh, Jung Kwon; Kim, Byung Jin; Sung, Ki Chul; Kang, Jin Ho; Lee, Man Ho; Park, Jung Ro

2010-04-01

The correlation between brain natruretic peptide (BNP) level and cardiac autonomic function has been studied in type 2 diabetic patients. However, there is limited data from patients with normal systolic function. We evaluated the association between heart rate recovery (HRR) representing autonomic dysfunction and three plasma BNP levels: pre-exercise, post-exercise, and change during exercise in patients with normal systolic function. Subjects included 105 patients with chest pain and normal systolic function. HRR was defined as the difference between the peak heart rate and the rate measured two minutes after completion of a treadmill exercise test. We measured plasma BNP levels before exercise, 5 minutes after completion of exercise, and during exercise (absolute value of difference between pre- and post-exercise BNP levels). Patients with abnormal HRR values (

Non-invasive ventilation abolishes the IL-6 response to exercise in muscle-wasted COPD patients: a pilot study.

PubMed

Hannink, J D C; van Hees, H W H; Dekhuijzen, P N R; van Helvoort, H A C; Heijdra, Y F

2014-02-01

Systemic inflammation in patients with chronic obstructive pulmonary disease (COPD) has been related to the development of comorbidities. The level of systemic inflammatory mediators is aggravated as a response to exercise in these patients. The aim of this study was to investigate whether unloading of the respiratory muscles attenuates the inflammatory response to exercise in COPD patients. In a cross-over design, eight muscle-wasted stable COPD patients performed 40 W constant work-rate cycle exercise with and without non-invasive ventilation support (NIV vs control). Patients exercised until symptom limitation for maximally 20 min. Blood samples were taken at rest and at isotime or immediately after exercise. Duration of control and NIV-supported exercise was similar, both 12.9 ± 2.8 min. Interleukin- 6 (IL-6) plasma levels increased significantly by 25 ± 9% in response to control exercise, but not in response to NIV-supported exercise. Leukocyte concentrations increased similarly after control and NIV-supported exercise by ∼15%. Plasma concentrations of C-reactive protein, carbonylated proteins, and production of reactive oxygen species by blood cells were not affected by both exercise modes. This study demonstrates that NIV abolishes the IL-6 response to exercise in muscle-wasted patients with COPD. These data suggest that the respiratory muscles contribute to exercise-induced IL-6 release in these patients. © 2012 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Exercise physiology with a left ventricular assist device: Analysis of heart-pump interaction with a computational simulator.

PubMed

Fresiello, Libera; Rademakers, Frank; Claus, Piet; Ferrari, Gianfranco; Di Molfetta, Arianna; Meyns, Bart

2017-01-01

Patients with a Ventricular Assist Device (VAD) are hemodynamically stable but show an impaired exercise capacity. Aim of this work is to identify and to describe the limiting factors of exercise physiology with a VAD. We searched for data concerning exercise in heart failure condition and after VAD implantation from the literature. Data were analyzed by using a cardiorespiratory simulator that worked as a collector of inputs coming from different papers. As a preliminary step the simulator was used to reproduce the evolution of hemodynamics from rest to peak exercise (ergometer cycling) in heart failure condition. Results evidence an increase of cardiac output of +2.8 l/min and a heart rate increase to 67% of the expected value. Then, we simulated the effect of a continuous-flow VAD at both rest and exercise. Total cardiac output increases of +3.0 l/min (+0.9 l/min due to the VAD and +2.1 l/min to the native ventricle). Since the left ventricle works in a non-linear portion of the diastolic stiffness line, we observed a consistent increase of pulmonary capillary wedge pressure (from 14 to 20 mmHg) for a relatively small increase of end-diastolic volume (from 182 to 189 cm3). We finally increased VAD speed during exercise to the maximum possible value and we observed a reduction of wedge pressure (-4.5 mmHg), a slight improvement of cardiac output (8.0 l/min) and a complete unloading of the native ventricle. The VAD can assure a proper hemodynamics at rest, but provides an insufficient unloading of the left ventricle and does not prevent wedge pressure from rising during exercise. Neither the VAD provides major benefits during exercise in terms of total cardiac output, which increases to a similar extend to an unassisted heart failure condition. VAD speed modulation can contribute to better unload the ventricle but the maximal flow reachable with the current devices is below the cardiac output observed in a healthy heart.

Neural Basis of Working Memory Enhancement after Acute Aerobic Exercise: fMRI Study of Preadolescent Children.

PubMed

Chen, Ai-Guo; Zhu, Li-Na; Yan, Jun; Yin, Heng-Chan

2016-01-01

Working memory lies at the core of cognitive function and plays a crucial role in children's learning, reasoning, problem solving, and intellectual activity. Behavioral findings have suggested that acute aerobic exercise improves children's working memory; however, there is still very little knowledge about whether a single session of aerobic exercise can alter working memory's brain activation patterns, as assessed by functional magnetic resonance imaging (fMRI). Therefore, we investigated the effect of acute moderate-intensity aerobic exercise on working memory and its brain activation patterns in preadolescent children, and further explored the neural basis of acute aerobic exercise on working memory in these children. We used a within-subjects design with a counterbalanced order. Nine healthy, right-handed children were scanned with a Siemens MAGNETOM Trio 3.0 Tesla magnetic resonance imaging scanner while they performed a working memory task (N-back task), following a baseline session and a 30-min, moderate-intensity exercise session. Compared with the baseline session, acute moderate-intensity aerobic exercise benefitted performance in the N-back task, increasing brain activities of bilateral parietal cortices, left hippocampus, and the bilateral cerebellum. These data extend the current knowledge by indicating that acute aerobic exercise enhances children's working memory, and the neural basis may be related to changes in the working memory's brain activation patterns elicited by acute aerobic exercise.

Recovery from Short Term Intense Exercise: Its Relation to Capillary Supply and Lactate Release,

DTIC Science & Technology

1982-01-01

accumulate at a higher rate in fast twitch (FT or Type II) than in slow twitch (ST or Type I) fibers of exercised muscles . Lactate form- ed and accumulated...is made up by a high percentage of FT fibers than can be expected in a " slow twitch " muscle . Moreover, the over-all metabolic profile of the ST fiber...local muscular fatigue. Eur. J. Appl. Physiol. 38, 9-15 (1978b) Baldwin, K.M., Tipton, C.M.: Work and metabolic patterns of fast and slow twitch

Body heat storage during intermittent work in hot-dry and warm-wet environments.

PubMed

Stapleton, Jill M; Wright, Heather E; Hardcastle, Stephen G; Kenny, Glen P

2012-10-01

We examined heat balance using an American Conference of Governmental Industrial Hygienists threshold limit value allocated exercise protocol in hot-dry (HD; 46 °C, 10% relative humidity (RH)) and warm-wet (WW; 33 °C, 60% RH) environments of equivalent WBGT (29 °C) for different clothing ensembles. Whole-body heat exchange and changes in body heat content (ΔH(b)) were measured using simultaneous direct whole-body and indirect calorimetry. Eight males performed six 15-min cycling periods at a constant rate of metabolic heat production (360 W) interspersed by 5-min rest periods for six experimental trials: HD and WW environments for a seminude control (CON), modified work uniform (MWU, moisture permeable top and work pants), and standard work uniform (SWU, work coveralls and cotton undergarments). Whole-body evaporative and dry heat exchange, rectal temperature (T(re)), and heart rate were measured continuously. The cumulative ΔH(b) during the 2 h intermittent exercise protocol was similar between HD and WW environments for each of the clothing ensembles (CON, 387 ± 55 vs. 435 ± 49 kJ; MWU, 485 ± 58 vs. 531 ± 61 kJ; SWU, 585 ± 74 vs. 660 ± 54 kJ, respectively). Similarly, no differences in T(re) (CON, 37.67 ± 0.07 vs. 37.48 ± 0.08 °C; MWU, 37.73 ± 0.08 vs. 37.53 ± 0.09 °C; SWU, 38.01 ± 0.09 vs. 37.94 ± 0.05 °C) or heat rate (CON, 93 ± 3 vs. 84 ± 3 beats·min⁻¹; MWU, 102 ± 5 vs. 95 ± 9 beats·min⁻¹; SWU, 119 ± 8 vs. 110 ± 9 beats·min⁻¹) were observed at the end of the 2 h intermittent exercise protocol in HD vs. WW environments, respectively. We showed similar levels of thermal and cardiovascular strain for intermittent work performed in high heat stress conditions of varying environmental conditions but similar WBGT.

Experimental protocol of a randomized controlled clinical trial investigating the effects of personalized exercise rehabilitation on kidney transplant recipients' outcomes.

PubMed

Kastelz, Alexandra; Tzvetanov, Ivo G; Fernhall, Bo; Shetty, Aneesha; Gallon, Lorenzo; West-Thielke, Patricia; Hachaj, Greg; Grazman, Mark; Benedetti, Enrico

2015-11-01

This randomized controlled trial (RCT) will investigate the effects of a personalized exercise rehabilitation regimen on return to work and find work rate, vascular health, functional capacity, quality of life, kidney function, and body composition in kidney transplant (KT) recipients. This RCT will recruit 120 men and/or women who have had a KT to participate in a 12 month exercise intervention or control (standard clinical care only) group. The 12 month exercise intervention will consist of one-on-one, progressive exercise rehabilitation sessions twice a week, for 60 min each session. The control group will continue standard clinical care as recommended by their post-transplant medical team without any intervention. The primary outcomes will be assessments of vascular structure and function, walking and strength measures to assess functional capacity, blood markers to assess kidney function, questionnaires to assess quality of life, DXA body scan to assess body composition, and a 1-week free living physical activity assessment. Additionally, employment status will be assessed. These assessments will be performed at baseline, 6 months, and 12 months. This investigation will increase the understanding of the role exercise rehabilitation has on managing the physiological and psychological health of the individual as well as on the individual's personal economic impact (via employment status). This study design has the potential to assist in constructing an effective exercise rehabilitation program that can be incorporated into part of standard post-transplant care. Copyright © 2015 Elsevier Inc. All rights reserved.

Effects of active recovery on autonomic and haemodynamic responses after aerobic exercise.

PubMed

Soares, Antonio H G; Oliveira, Tiago P; Cavalcante, Bruno R; Farah, Breno Q; Lima, Aluísio H R A; Cucato, Gabriel G; Cardoso, Crivaldo G; Ritti-Dias, Raphael M

2017-01-01

The aim of this study was to examine the effect of active recovery on autonomic and haemodynamic responses after exercise in healthy adults. Nineteen healthy young male individuals underwent two experimental sessions: exercise with active recovery (AR) and exercise with passive recovery (PR). The exercise sessions comprised three phases: warm-up (5 min), exercise phase (cycle ergometer, 30 min, intensity between 60 and 70% of the heart rate reserve) and recovery (5 min). In the AR, the subjects remained cycling in the recovery phase at intensity between 30% and 35% of heart rate reserve, while in the PR, the subjects stopped the exercise after finishing the exercise phase. Blood pressure and heart rate were measured before and over the 30 min after the interventions. There were no differences for systolic and diastolic blood pressures, heart rate and rate pressure product between active and passive recovery sessions. Also, all heart rate variability parameters changed similarly after exercise with passive or active recovery sessions. In summary, exercise with active recovery does not affect the autonomic and haemodynamic responses after moderate-intensity aerobic exercise in healthy young male individuals. © 2015 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

Skylab experiment M-171 'Metabolic Activity' - Results of the first manned mission

NASA Technical Reports Server (NTRS)

Michel, E. L.; Rummel, J. A.; Sawin, C. F.

1975-01-01

The experiment was performed to ascertain whether man's ability to perform mechanical work would be altered as a result of exposure to the weightless environment. Skylab II crewmen were exercised on a bicycle ergometer at loads approximating 25%, 50%, and 75% of their maximum oxygen uptake while their physiological responses were monitored. The results of these tests indicate that the crewmen had no significant decrement in their response to exercise during their exposure to zero gravity. Immediately postflight, however, all crewmen demonstrated an inability to perform the programmed exercise with the same metabolic effectiveness as they did both preflight and inflight. The most significant changes were elevated heart rates for the same work load and oxygen consumption (decreased oxygen pulse), decreased stroke volume, and decreased cardiac output at the same oxygen consumption level. It is apparent that the changes occurred inflight, but did not manifest themselves until the crewmen attempted to readapt to the 1-G environment.

Specific Circuit Training in Young Judokas: Effects of Rest Duration

ERIC Educational Resources Information Center

Baudry, Stephane; Roux, Patrick

2009-01-01

Ten adolescent judokas performed circuit training consisting of six 40-s periods of judo exercises separated by 40 s (CT1:1), 120 s (CT1:3), or 200 s (CT1:5) of rest. Heart rate, blood lactate concentration, and the number of repetitions were recorded. Heart rate reached [approximately]180 beats[middle dot]min-1 at the end of work periods, with…

Child Care: States Exercise Flexibility in Setting Reimbursement Rates and Providing Access for Low-Income Children. Report to Congressional Requesters.

ERIC Educational Resources Information Center

Shaul, Marnie S.

In order to promote low-income parents' job preparation and work efforts, states were given greater flexibility to design programs using federal funds to subsidize child care for low-income families. At Congressional request, this report from the General Accounting Office describes how states set reimbursement rates and calculates the extent to…

Effect of endurance exercise on respiratory muscle function in patients with cystic fibrosis.

PubMed

Reilly, Charles C; Ward, Katie; Jolley, Caroline J; Frank, Lucy A; Elston, Caroline; Moxham, John; Rafferty, Gerrard F

2012-03-15

During exercise, patients with cystic fibrosis (CF) dynamically hyperinflate, which imposes both elastic and threshold loads on the inspiratory muscles and places them at a mechanical disadvantage due to muscle shortening. Conversely, dynamic hyperinflation imposes a progressively resistive load and lengthens the expiratory muscles potentially increasing their susceptibility to develop low frequency fatigue (LFF). The aim of the study was to determine whether high intensity endurance exercise leads to the development of LFF in either the diaphragm or expiratory abdominal wall muscles in patients with CF. Ten patients and ten healthy individuals were studied. Twitch transdiaphragmatic pressure (TwP(di)) and twitch abdominal pressure (TwT(10)) were measured before and after exhaustive endurance cycle exercise at 80% of their previously determined maximum work rate. There was no difference in TwP(di) or TwT(10) at 20, 40 or 60 min post exercise compared to pre-exercise resting values in any of the participants, indicating that overt LFF of the respiratory muscles did not develop. Copyright © 2012 Elsevier B.V. All rights reserved.

Separate aftereffects of morning and evening exercise on ambulatory blood pressure in prehypertensive men.

PubMed

Brito, Leandro C; Rezende, Rafael A; Mendes, Caroline; Silva-Junior, Natan D; Tinucci, Taís; Cipolla-Neto, José; de Moraes Forjaz, Cláudia L

2018-01-01

Clinic postexercise hypotension (PEH) is different after aerobic exercise performed in the morning and in the evening. Thus, ambulatory PEH should also differ after exercises conducted at different times of day. However, because of the circadian pattern of blood pressure (BP), ambulatory PEH should be assessed considering a control condition. Thus, this study was designed to verify the effects of morning and evening exercises on postexercise ambulatory BP averages and circadian parameters by comparing responses obtained at each time of day after an exercise and a control session. Thirteen prehypertensive men underwent four sessions (randomized order): two in the morning (9 am) and two in the evening (6:30 pm). At each time of day, a control (C) and an exercise (E: cycle ergometer 45 min, 50% VO2peak) sessions were performed. After the sessions, an ambulatory BP and heart rate (HR) monitoring was started for 24 h. Paired t-test or Wilcoxon Signed Rank Test were used to compare the E and the C sessions at each time of day. In the morning, 24 h, daytime and nighttime HR were higher after the E than the C session. In the evening, nighttime systolic BP (116±11 vs. 120±10 mmHg, P=0.04) and rate pressure product (7981±1294 vs. 8583±1523 mmHg.bpm, P=0.04), as well as MESOR (128±11 vs. 130±10 mmHg, P=0.03) were lower in the E than the C session. In prehypertensive men, morning exercise increased ambulatory HR, while evening exercise decreased nighttime BP and cardiac work, reducing the MESOR of systolic BP.

Impact of aerobic exercise on haemostatic indices in paediatric patients with haemophilia.

PubMed

Kumar, Riten; Bouskill, Vanessa; Schneiderman, Jane E; Pluthero, Fred G; Kahr, Walter H A; Craik, Allison; Clark, Dewi; Whitney, Karen; Zhang, Christine; Rand, Margaret L; Carcao, Manuel

2016-06-02

This study investigated the impact of aerobic exercise on laboratory assessments of haemostatic activity in boys (5-18 years of age) with haemophilia A (HA) or B (HB), examining the hypothesis that laboratory coagulation parameters temporarily improve with exercise. Thirty subjects meeting eligibility criteria (19 HA; 11 HB; mean age: 12.8 years) were invited to participate. They underwent a replacement factor washout period and were advised against strenuous activity for three days prior to the planned intervention. At study visit, baseline blood samples were drawn prior to exercise on a stationary cycle ergometer, aiming to attain 3 minutes (min) of cycling at 85 % of predicted maximum heart rate. Blood work was repeated 5 min (t5) and 60 min (t60) post exercise completion. Samples were assessed for platelet count (PC), factor VIII activity ( C), von Willebrand antigen (VWF:Ag), ristocetin cofactor activity (VWF:RCo) and platelet function analysis (PFA-100); maximum rate of thrombus generation (MRTG) in blood was measured via thromboelastography and plasma peak thrombin generation (PTG) via calibrated automated thrombography. Mean duration of exercise was 13.9 (± 2.6) min. On average, t5 samples showed significant elevation, relative to baseline in PC, FVIII:C, VWF:Ag, VWF:RCo and PTG, while C, VWF:Ag, VWF:RCo and MRTG were significantly elevated in t60 samples. Within the cohort, participants with severe HA showed no change in C levels with exercise. The greatest improvement in haemostatic indices was observed in post-adolescent males with mild-moderate HA, who thus represent the group most likely to benefit from a reduction of bleeding risk in the setting of exercise.

Does Pre-Cooling With Whole-Body Immersion Affect Thermal Sensation or Perceived Exertion?: A Critically-Appraised Topic.

PubMed

Wohlfert, Timothy M; Miller, Kevin C

2018-02-21

Clinical Scenario: Exertional heat stroke (EHS) is a potentially deadly heat illness and poses a significant health risk to athletes; EHS survival rates are near 100% if properly recognized and treated. 1 Whole body cold water immersion (CWI) is the most effective method of lowering body core temperature. 2 Precooling (PC) with CWI before exercise may prevent severe hyperthermia and/or EHS by increasing the body's overall heat-storage capacity. 3 However, PC may also alter athletes' perception of how hot they feel or how hard they are exercising. Consequently, they may be unable to accurately perceive their body core temperature or how hard they are working which may predispose them to severe hyperthermia or EHS. Does PC with whole-body CWI affect thermal sensation (TS) or rating of perceived exertion (RPE) during exercise in the heat? In four studies, 4-7 RPE during exercise ranged from 12 ± 2 to 20 ± 3 with no clinically meaningful differences between PC and control trials. Thermal sensation scores ranged from 2 ± 1 to 8 ± 0.5 in control trials and from 2 ± 1 to 7.5 ± 0.5 during PC trials. Clinical Bottom Line: Precooling did not cause clinically-meaningful differences in RPE or TS during exercise. It is unlikely PC would predispose athletes to EHS by altering perceptions of exercise intensity or body core temperature. Strength of Recommendation: None of the reviewed studies 4-7 (all level 2 studies with PEDro scores ≥5) suggest PC with CWI influences RPE or TS in exercising males.

Attenuation of Exaggerated Exercise Blood Pressure Response in African-American Women by Regular Aerobic Physical Activity

PubMed Central

Bond, Vernon; Millis, Richard M.; Adams, R. George; Oke, Luc M.; Enweze, Larry; Blakely, Raymond; Banks, Marshall; Thompson, Terry; Obisesan, Thomas; Sween, Jennifer C.

2011-01-01

Introduction A hyperreactive blood pressure response to exercise is a predictor of developing hypertension. The present study determined the influence of physical activity on an exaggerated exercise blood pressure response (EEBPR) in normotensive African-American women. Methods We screened 36 women 18–26 years of age for EEBPR defined as a ≥50 mm Hg difference in systolic blood pressure at rest and during exercise at 50% peak oxygen uptake (VO2peak). Seven subjects demonstrated an EEBPR and participated in the study. Study participants trained for eight weeks on a bicycle ergometer at a work intensity of 70% VO2peak. Blood pressure, heart rate, cardiac output (CO), stroke volume (SV), and total peripheral vascular resistance (TPR) were determined at baseline and during submaximal exercise at power outputs of 30 W and 50% VO2peak. Subjects served as their own controls, and data were evaluated by using a paired t test at P<.05. Results Effectiveness of the intervention was shown by a significantly greater VO2peak associated with significant decrements in systolic and mean arterial pressures at power outputs of 30 W and 50% VO2peak. A significant decrement in heart rate was observed during exercise at 30 W. Significant increments in CO and SV and decrement in TPR were found during exercise at 50% VO2peak. Conclusion The reduction in TPR associated with regular aerobic physical activity may attenuate the EEBPR and decrease the risk for hypertension in normotensive, young-adult, African-American women. PMID:16315376

Effects of respiratory muscle work on respiratory and locomotor blood flow during exercise.

PubMed

Dominelli, Paolo B; Archiza, Bruno; Ramsook, Andrew H; Mitchell, Reid A; Peters, Carli M; Molgat-Seon, Yannick; Henderson, William R; Koehle, Michael S; Boushel, Robert; Sheel, A William

2017-11-01

What is the central question of this study? Does manipulation of the work of breathing during high-intensity exercise alter respiratory and locomotor muscle blood flow? What is the main finding and its importance? We found that when the work of breathing was reduced during exercise, respiratory muscle blood flow decreased, while locomotor muscle blood flow increased. Conversely, when the work of breathing was increased, respiratory muscle blood flow increased, while locomotor muscle blood flow decreased. Our findings support the theory of a competitive relationship between locomotor and respiratory muscles during intense exercise. Manipulation of the work of breathing (WOB) during near-maximal exercise influences leg blood flow, but the effects on respiratory muscle blood flow are equivocal. We sought to assess leg and respiratory muscle blood flow simultaneously during intense exercise while manipulating WOB. Our hypotheses were as follows: (i) increasing the WOB would increase respiratory muscle blood flow and decrease leg blood flow; and (ii) decreasing the WOB would decrease respiratory muscle blood flow and increase leg blood flow. Eight healthy subjects (n = 5 men, n = 3 women) performed a maximal cycle test (day 1) and a series of constant-load exercise trials at 90% of peak work rate (day 2). On day 2, WOB was assessed with oesophageal balloon catheters and was increased (via resistors), decreased (via proportional assist ventilation) or unchanged (control) during the trials. Blood flow was assessed using near-infrared spectroscopy optodes placed over quadriceps and the sternocleidomastoid muscles, coupled with a venous Indocyanine Green dye injection. Changes in WOB were significantly and positively related to changes in respiratory muscle blood flow (r = 0.73), whereby increasing the WOB increased blood flow. Conversely, changes in WOB were significantly and inversely related to changes in locomotor blood flow (r = 0.57), whereby decreasing the WOB increased locomotor blood flow. Oxygen uptake was not different during the control and resistor trials (3.8 ± 0.9 versus 3.7 ± 0.8 l min -1 , P > 0.05), but was lower on the proportional assist ventilator trial (3.4 ± 0.7 l min -1 , P < 0.05) compared with control. Our findings support the concept that respiratory muscle work significantly influences the distribution of blood flow to both respiratory and locomotor muscles. © 2017 The Authors. Experimental Physiology © 2017 The Physiological Society.

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

Effect of breathing oxygen-enriched air on exercise performance in patients with precapillary pulmonary hypertension: randomized, sham-controlled cross-over trial.

PubMed

Ulrich, Silvia; Hasler, Elisabeth D; Saxer, Stéphanie; Furian, Michael; Müller-Mottet, Séverine; Keusch, Stephan; Bloch, Konrad E

2017-04-14

The purpose of the current trial was to test the hypothesis that breathing oxygen-enriched air increases exercise performance of patients with pulmonary arterial or chronic thrombo-embolic pulmonary hypertension (PAH/CTEPH) and to investigate involved mechanisms. Twenty-two patients with PAH/CTEPH, eight women, means ± SD 61 ± 14 years, resting mPAP 35 ± 9mmHg, PaO2 ambient air >7.3 kPa, underwent four bicycle ergospirometries to exhaustion on different days, while breathing oxygen-enriched (FiO2 0.50, hyperoxia) or ambient air (FiO2 0.21, normoxia) using progressively increased or constant load protocols (with 75% maximal work rate under FiO2 0.21), according to a randomized, sham-controlled, single-blind, cross-over design. ECG, pulmonary gas-exchange, arterial blood gases, cerebral and quadriceps muscle tissue oxygenation (CTO and QMTO) by near-infrared spectroscopy were measured. In ramp exercise, maximal work rate increased from 113 ± 38 W with normoxia to 132 ± 48 W with hyperoxia, mean difference 19.7 (95% CI 10.5-28.9) W, P < 0.001. Constant load exercise endurance increased from 571 ± 443 to 1242 ± 514 s, mean difference 671 (95% CI 392-951) s, P < 0.001. At end-exercise with hyperoxia PaO2, CTO, QMTO, and PaCO2 were increased, and ventilatory equivalents for CO2 were reduced while the physiological dead space/tidal volume ratio remained unchanged. In patients with PAH/CTEPH, breathing oxygen-enriched air provides major increases in exercise performance. This is related to an improved arterial oxygenation that promotes oxygen availability in muscles and brain and to a reduction of the excessive ventilatory response to exercise thereby enhancing ventilatory efficiency. Patients with PAH/CTEPH may therefore benefit from oxygen therapy during daily physical activities and training. clinicaltrials.gov Identifier: NCT01748474. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2017. For permissions, please email: journals.permissions@oup.com.

Construction of an isokinetic eccentric cycle ergometer for research and training.

PubMed

Elmer, Steven J; Martin, James C

2013-08-01

Eccentric cycling serves a useful exercise modality in clinical, research, and sport training settings. However, several constraints can make it difficult to use commercially available eccentric cycle ergometers. In this technical note, we describe the process by which we built an isokinetic eccentric cycle ergometer using exercise equipment modified with commonly available industrial parts. Specifically, we started with a used recumbent cycle ergometer and removed all the original parts leaving only the frame and seat. A 2.2 kW electric motor was attached to a transmission system that was then joined with the ergometer. The motor was controlled using a variable frequency drive, which allowed for control of a wide range of pedaling rates. The ergometer was also equipped with a power measurement device that quantified work, power, and pedaling rate and provided feedback to the individual performing the exercise. With these parts along with some custom fabrication, we were able to construct an isokinetic eccentric cycle ergometer suitable for research and training. This paper offers a guide for those individuals who plan to use eccentric cycle ergometry as an exercise modality and wish to construct their own ergometer.

Application of machine learning techniques to analyse the effects of physical exercise in ventricular fibrillation.

PubMed

Caravaca, Juan; Soria-Olivas, Emilio; Bataller, Manuel; Serrano, Antonio J; Such-Miquel, Luis; Vila-Francés, Joan; Guerrero, Juan F

2014-02-01

This work presents the application of machine learning techniques to analyse the influence of physical exercise in the physiological properties of the heart, during ventricular fibrillation. To this end, different kinds of classifiers (linear and neural models) are used to classify between trained and sedentary rabbit hearts. The use of those classifiers in combination with a wrapper feature selection algorithm allows to extract knowledge about the most relevant features in the problem. The obtained results show that neural models outperform linear classifiers (better performance indices and a better dimensionality reduction). The most relevant features to describe the benefits of physical exercise are those related to myocardial heterogeneity, mean activation rate and activation complexity. © 2013 Published by Elsevier Ltd.

Ingestion of High Molecular Weight Carbohydrate Enhances Subsequent Repeated Maximal Power: A Randomized Controlled Trial

PubMed Central

Oliver, Jonathan M.; Almada, Anthony L.; Van Eck, Leighsa E.; Shah, Meena; Mitchell, Joel B.; Jones, Margaret T.; Jagim, Andrew R.; Rowlands, David S.

2016-01-01

Athletes in sports demanding repeat maximal work outputs frequently train concurrently utilizing sequential bouts of intense endurance and resistance training sessions. On a daily basis, maximal work within subsequent bouts may be limited by muscle glycogen availability. Recently, the ingestion of a unique high molecular weight (HMW) carbohydrate was found to increase glycogen re-synthesis rate and enhance work output during subsequent endurance exercise, relative to low molecular weight (LMW) carbohydrate ingestion. The effect of the HMW carbohydrate, however, on the performance of intense resistance exercise following prolonged-intense endurance training is unknown. Sixteen resistance trained men (23±3 years; 176.7±9.8 cm; 88.2±8.6 kg) participated in a double-blind, placebo-controlled, randomized 3-way crossover design comprising a muscle-glycogen depleting cycling exercise followed by ingestion of placebo (PLA), or 1.2 g•kg•bw-1 of LMW or HMW carbohydrate solution (10%) with blood sampling for 2-h post-ingestion. Thereafter, participants performed 5 sets of 10 maximal explosive repetitions of back squat (75% of 1RM). Compared to PLA, ingestion of HMW (4.9%, 90%CI 3.8%, 5.9%) and LMW (1.9%, 90%CI 0.8%, 3.0%) carbohydrate solutions substantially increased power output during resistance exercise, with the 3.1% (90% CI 4.3, 2.0%) almost certain additional gain in power after HMW-LMW ingestion attributed to higher movement velocity after force kinematic analysis (HMW-LMW 2.5%, 90%CI 1.4, 3.7%). Both carbohydrate solutions increased post-exercise plasma glucose, glucoregulatory and gut hormones compared to PLA, but differences between carbohydrates were unclear; thus, the underlying mechanism remains to be elucidated. Ingestion of a HMW carbohydrate following prolonged intense endurance exercise provides superior benefits to movement velocity and power output during subsequent repeated maximal explosive resistance exercise. This study was registered with clinicaltrials.gov (NCT02778373). PMID:27636206

Ingestion of High Molecular Weight Carbohydrate Enhances Subsequent Repeated Maximal Power: A Randomized Controlled Trial.

PubMed

Oliver, Jonathan M; Almada, Anthony L; Van Eck, Leighsa E; Shah, Meena; Mitchell, Joel B; Jones, Margaret T; Jagim, Andrew R; Rowlands, David S

2016-01-01

Athletes in sports demanding repeat maximal work outputs frequently train concurrently utilizing sequential bouts of intense endurance and resistance training sessions. On a daily basis, maximal work within subsequent bouts may be limited by muscle glycogen availability. Recently, the ingestion of a unique high molecular weight (HMW) carbohydrate was found to increase glycogen re-synthesis rate and enhance work output during subsequent endurance exercise, relative to low molecular weight (LMW) carbohydrate ingestion. The effect of the HMW carbohydrate, however, on the performance of intense resistance exercise following prolonged-intense endurance training is unknown. Sixteen resistance trained men (23±3 years; 176.7±9.8 cm; 88.2±8.6 kg) participated in a double-blind, placebo-controlled, randomized 3-way crossover design comprising a muscle-glycogen depleting cycling exercise followed by ingestion of placebo (PLA), or 1.2 g•kg•bw-1 of LMW or HMW carbohydrate solution (10%) with blood sampling for 2-h post-ingestion. Thereafter, participants performed 5 sets of 10 maximal explosive repetitions of back squat (75% of 1RM). Compared to PLA, ingestion of HMW (4.9%, 90%CI 3.8%, 5.9%) and LMW (1.9%, 90%CI 0.8%, 3.0%) carbohydrate solutions substantially increased power output during resistance exercise, with the 3.1% (90% CI 4.3, 2.0%) almost certain additional gain in power after HMW-LMW ingestion attributed to higher movement velocity after force kinematic analysis (HMW-LMW 2.5%, 90%CI 1.4, 3.7%). Both carbohydrate solutions increased post-exercise plasma glucose, glucoregulatory and gut hormones compared to PLA, but differences between carbohydrates were unclear; thus, the underlying mechanism remains to be elucidated. Ingestion of a HMW carbohydrate following prolonged intense endurance exercise provides superior benefits to movement velocity and power output during subsequent repeated maximal explosive resistance exercise. This study was registered with clinicaltrials.gov (NCT02778373).

Identifying potential barriers to physical activity adherence: anxiety sensitivity and body mass as predictors of fear during exercise.

PubMed

Smits, Jasper A J; Tart, Candyce D; Presnell, Katherine; Rosenfield, David; Otto, Michael W

2010-01-01

A growing body of work suggests that obese adults are less likely to adhere to exercise than normal-weight adults because they experience greater levels of discomfort and distress during exercise sessions. The present study introduces and provides a preliminary test of the hypothesis that the distress experienced during exercise among persons with elevated body mass index is particularly high among those who fear somatic arousal (i.e. elevated anxiety sensitivity [AS]). Young adults were randomly assigned to complete 20 min of treadmill exercise (at 70% of their age-adjusted predicted maximum heart rate) or 20 min of rest. Body mass, AS, and negative affect were measured at baseline, and fear was measured at 4-min intervals during the experimental phase. Consistent with the authors' hypothesis, there was a significant Exercise x BMI x ASI interaction (sr(2) = .08), suggesting that the greatest fear levels during exercise were observed among participants with high body mass, but only if they also had elevated AS. These findings offer a new approach for identifying specific vulnerable individuals and have clear clinical implications, given that the amplification factor of AS can be modified with clinical intervention.

Voluntary Wheel Running Induces Exercise-Seeking Behavior in Male Rats: A Behavioral Study.

PubMed

Naghshvarian, Mojtaba; Zarrindast, Mohammad-Reza; Sajjadi, Seyedeh Fatemeh

2017-12-01

Research evidence shows that exercise is associated with positive physical and mental health. Moreover, exercise and wheel running in rats activate overlapping neural systems and reward system. The most commonly used models for the study of rewarding and aversive effects of exercise involve using treadmill and wheel running paradigms in mice or rats. The purpose of our experiment was to study the influence of continuous voluntary exercise on exercise-seeking behavior. In this experimental study, we used 24 adult male Sprague-Dawley rats weighing 275-300 g on average. Rats were divided into 3 experimental groups for 4 weeks of voluntary wheel running. Each rat ran in the cage equipped with a wheel during 24 hours. A within-subject repeated measure design was employed to evaluate the trend of running and running rates. We found that time and higher levels of exercise will increase exercise tendency. Our results also show that the interaction of exercise within 4 weeks and different levels of exercise can significantly promote rats' exercise-seeking behavior (F = 5.440; df = 2.08; P < 0.001). Our data suggest that voluntary wheel running can increase the likelihood of extreme and obsessive exercising which is a form of non-drug addiction. 2017 The Author(s). This is an open-access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Alkalosis increases muscle K+ release, but lowers plasma [K+] and delays fatigue during dynamic forearm exercise

PubMed Central

Sostaric, Simon M; Skinner, Sandford L; Brown, Malcolm J; Sangkabutra, Termboon; Medved, Ivan; Medley, Tanya; Selig, Steve E; Fairweather, Ian; Rutar, Danny; McKenna, Michael J

2006-01-01

Alkalosis enhances human exercise performance, and reduces K+ loss in contracting rat muscle. We investigated alkalosis effects on K+ regulation, ionic regulation and fatigue during intense exercise in nine untrained volunteers. Concentric finger flexions were conducted at 75% peak work rate (∼3 W) until fatigue, under alkalosis (Alk, NaHCO3, 0.3 g kg−1) and control (Con, CaCO3) conditions, 1 month apart in a randomised, double-blind, crossover design. Deep antecubital venous (v) and radial arterial (a) blood was drawn at rest, during exercise and recovery, to determine arterio-venous differences for electrolytes, fluid shifts, acid–base and gas exchange. Finger flexion exercise barely perturbed arterial plasma ions and acid–base status, but induced marked arterio-venous changes. Alk elevated [HCO3−] and PCO2, and lowered [H+] (P < 0.05). Time to fatigue increased substantially during Alk (25 ± 8%, P < 0.05), whilst both [K+]a and [K+]v were reduced (P < 0.01) and [K+]a-v during exercise tended to be greater (P= 0.056, n = 8). Muscle K+ efflux at fatigue was greater in Alk (21.2 ± 7.6 µmol min−1, 32 ± 7%, P < 0.05, n = 6), but peak K+ uptake rate was elevated during recovery (15 ± 7%, P < 0.05) suggesting increased muscle Na+,K+-ATPase activity. Alk induced greater [Na+]a, [Cl−]v, muscle Cl− influx and muscle lactate concentration ([Lac−]) efflux during exercise and recovery (P < 0.05). The lower circulating [K+] and greater muscle K+ uptake, Na+ delivery and Cl− uptake with Alk, are all consistent with preservation of membrane excitability during exercise. This suggests that lesser exercise-induced membrane depolarization may be an important mechanism underlying enhanced exercise performance with Alk. Thus Alk was associated with improved regulation of K+, Na+, Cl− and Lac−. PMID:16239279

Effect of dietary nitrate supplementation on conduit artery blood flow, muscle oxygenation, and metabolic rate during handgrip exercise.

PubMed

Craig, Jesse C; Broxterman, Ryan M; Smith, Joshua R; Allen, Jason David; Barstow, Thomas J

2018-05-03

Dietary nitrate supplementation has positive effects on mitochondrial and muscle contractile efficiency during large muscle mass exercise in humans, and on skeletal muscle blood flow (Q̇) in rats. However, concurrent measurement of these effects has not been performed in humans. Therefore, we assessed the influence of nitrate supplementation on Q̇ and muscle oxygenation characteristics during moderate (40%peak) and severe (85%peak) intensity handgrip exercise in a randomized, double-blind, crossover-design. Nine healthy men (age: 25{plus minus}2 yrs) completed four constant-power exercise tests (two per intensity) randomly assigned to condition (nitrate-rich (Nitrate) or nitrate-poor (Placebo) beetroot supplementation) and intensity (40%peak or 85%peak). Resting mean arterial pressure was lower after Nitrate compared to Placebo (84{plus minus}4 vs 89{plus minus}4 mmHg; p<0.01). All subjects were able to sustain 10 min of exercise at 40%peak in both conditions. Nitrate had no effect on exercise tolerance during 85%peak (Nitrate: 358{plus minus}29, Placebo: 341{plus minus}34 s; p=0.3). Brachial artery Q̇ was not different after Nitrate at rest or any time during exercise. Deoxygenated-[hemoglobin+myoglobin] was not different for 40%peak (p>0.05), but was elevated throughout 85%peak (p<0.05) after Nitrate. The metabolic cost (V̇O2) was not different at end exercise, however, the V̇O 2 primary amplitude at the onset of exercise was elevated after Nitrate for the 85%peak work rate (96{plus minus}20 vs 72{plus minus}12 ml/min; p<0.05) and had a faster response. These findings suggest that an acute dose of Nitrate reduces resting blood pressure and speeds V̇O 2 kinetics in young adults, but does not augment Q̇ or reduce steady-state V̇O 2 during small muscle mass handgrip exercise.

Beneficial effects of training at the anaerobic threshold in addition to pharmacotherapy on weight loss, body composition, and exercise performance in women with obesity.

PubMed

Ozcelik, Oguz; Ozkan, Yusuf; Algul, Sermin; Colak, Ramis

2015-01-01

The aim of this study was to determine and compare the effects of weight loss achieved through orlistat therapy alone or a combination of orlistat and an aerobic exercise training program on aerobic fitness and body composition in obese females. Twenty-eight obese patients were randomly assigned to receive 12-week treatment with hypocaloric diet-orlistat or diet-orlistat-exercise. Each participant performed an incremental ramp exercise test every 4 weeks to measure aerobic fitness. Fourteen participants performed continuous exercise (approximately 45 minutes per session) at a work rate corresponding to the anaerobic threshold three times per week. A decrease in the fat mass to body weight ratio of 3.8% (P=0.006) was observed at the end of the 12 weeks in the orlistat group, while a decrease of 9.5% (P=0.001) was seen in the orlistat-exercise group. Maximal exercise capacity increased by 46.5% in the orlistat-exercise group and by 19.5% in the orlistat group. While orlistat therapy resulted in an improvement in body composition and aerobic fitness at the end of the 12-week period, its combination with exercise training provided improvements in the same parameters within the first 4 weeks of the study. These additional beneficial effects of combining aerobic exercise with orlistat therapy are important with regards to obesity-associated risk factors.

Self-paced exercise program for office workers: impact on productivity and health outcomes.

PubMed

Low, David; Gramlich, Martha; Engram, Barbara Wright

2007-03-01

The impact of a self-paced exercise program on productivity and health outcomes of 32 adult workers in a large federal office complex was investigated during 3 months. Walking was the sole form of exercise. The first month, during which no walking occurred, was the control period. The second and third months were the experimental period. Participants were divided into three levels based on initial weight and self-determined walking distance goals. Productivity (using the Endicott Work Productivity Scale), walking distance (using a pedometer), and health outcomes (blood pressure, weight, pulse rate, and body fat percentage) were measured weekly. Results from this study, based on a paired t test analysis, suggest that although the self-paced exercise program had no impact on productivity, it lowered blood pressure and promoted weight loss. Further study using a larger sample and a controlled experimental design is recommended to provide conclusive evidence.

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

PubMed Central

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

2008-01-01

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

Dynamic water exercise in individuals with late poliomyelitis.

PubMed

Willén, C; Sunnerhagen, K S; Grimby, G

2001-01-01

To evaluate the specific effects of general dynamic water exercise in individuals with late effects of poliomyelitis. Before-after tests. A university hospital department. Twenty-eight individuals with late effects of polio, 15 assigned to the training group (TG) and 13 to the control group (CG). The TG completed a 40-minute general fitness training session in warm water twice weekly. Assessment instruments included the bicycle ergometer test, isokinetic muscle strength, a 30-meter walk indoors, Berg balance scale, a pain drawing, a visual analog scale, the Physical Activity Scale for the Elderly, and the Nottingham Health Profile (NHP). Peak load, peak work load, peak oxygen uptake, peak heart rate (HR), muscle function in knee extensors and flexors, and pain dimension of the NHP. The average training period was 5 months; compliance was 75% (range, 55-98). No negative effects were seen. The exercise did not influence the peak work load, peak oxygen uptake, or muscle function in knee extensors compared with the controls. However, a decreased HR at the same individual work load was seen, as well as a significantly lower distress in the dimension pain of the NHP. Qualitative aspects such as increased well-being, pain relief, and increased physical fitness were reported. A program of nonswimming dynamic exercises in heated water has a positive impact on individuals with late effects of polio, with a decreased HR at exercise, less pain, and a subjective positive experience. The program was well tolerated (no adverse effects were reported) and can be recommended for this group of individuals.

Do clinicians prescribe exercise similarly in patients with different cardiovascular diseases? Findings from the EAPC EXPERT working group survey.

PubMed

Hansen, Dominique; Rovelo Ruiz, Gustavo; Doherty, Patrick; Iliou, Marie-Christine; Vromen, Tom; Hinton, Sally; Frederix, Ines; Wilhelm, Matthias; Schmid, Jean-Paul; Abreu, Ana; Ambrosetti, Marco; Garcia-Porrero, Esteban; Coninx, Karin; Dendale, Paul

2018-05-01

Background Although disease-specific exercise guidelines for cardiovascular disease (CVD) are widely available, it remains uncertain whether these different exercise guidelines are integrated properly for patients with different CVDs. The aim of this study was to assess the inter-clinician variance in exercise prescription for patients with various CVDs and to compare these prescriptions with recommendations from the EXercise Prescription in Everyday practice and Rehabilitative Training (EXPERT) tool, a digital decision support system for integrated state-of-the-art exercise prescription in CVD. Design The study was a prospective observational survey. Methods Fifty-three CV rehabilitation clinicians from nine European countries were asked to prescribe exercise intensity (based on percentage of peak heart rate (HR peak )), frequency, session duration, programme duration and exercise type (endurance or strength training) for the same five patients. Exercise prescriptions were compared between clinicians, and relationships with clinician characteristics were studied. In addition, these exercise prescriptions were compared with recommendations from the EXPERT tool. Results A large inter-clinician variance was found for prescribed exercise intensity (median (interquartile range (IQR)): 83 (13) % of HR peak ), frequency (median (IQR): 4 (2) days/week), session duration (median (IQR): 45 (18) min/session), programme duration (median (IQR): 12 (18) weeks), total exercise volume (median (IQR): 1215 (1961) peak-effort training hours) and prescription of strength training exercises (prescribed in 78% of all cases). Moreover, clinicians' exercise prescriptions were significantly different from those of the EXPERT tool ( p < 0.001). Conclusions This study reveals significant inter-clinician variance in exercise prescription for patients with different CVDs and disagreement with an integrated state-of-the-art system for exercise prescription, justifying the need for standardization efforts regarding integrated exercise prescription in CV rehabilitation.

Work related and individual predictors for incident neck pain among office employees working with video display units

PubMed Central

Korhonen, T; Ketola, R; Toivonen, R; Luukkonen, R; Hakkanen, M; Viikari-Juntura, E

2003-01-01

Aims: To investigate work related and individual factors as predictors for incident neck pain among office employees working with video display units (VDUs). Methods: Employees in three administrative units of a medium sized city in Finland (n = 515) received mailed questionnaires in the baseline survey in 1998 and in the follow up survey in 1999. Response rate for the baseline was 81% (n = 416); respondents who reported neck pain for less than eight days during the preceding 12 months were included into the study cohort as healthy subjects (n = 232). The follow up questionnaire 12 months later was completed by 78% (n = 180). Incident neck cases were those reporting neck pain for at least eight days during the preceding 12 months. Results: The annual incidence of neck pain was 34.4% (95% CI 25.5 to 41.3). Poor physical work environment and poor placement of the keyboard increased the risk of neck pain. Among the individual factors, female sex was a strong predictor. Smoking showed a tendency for an increased risk of neck pain. There was an interaction between mental stress and physical exercise, those with higher mental stress and less physical exercise having especially high risk. Conclusion: In the prevention of neck disorders in office work with a high frequency of VDU tasks, attention should be given to the work environment in general and to the more specific aspects of VDU workstation layout. Physical exercise may prevent neck disorders among sedentary employees. PMID:12819280

Benefits of pulmonary rehabilitation in patients with COPD and normal exercise capacity.

PubMed

Lan, Chou-Chin; Chu, Wen-Hua; Yang, Mei-Chen; Lee, Chih-Hsin; Wu, Yao-Kuang; Wu, Chin-Pyng

2013-09-01

Pulmonary rehabilitation (PR) is beneficial for patients with COPD, with improvement in exercise capacity and health-related quality of life. Despite these overall benefits, the responses to PR vary significantly among different individuals. It is not clear if PR is beneficial for patients with COPD and normal exercise capacity. We aimed to investigate the effects of PR in patients with normal exercise capacity on health-related quality of life and exercise capacity. Twenty-six subjects with COPD and normal exercise capacity were studied. All subjects participated in 12-week, 2 sessions per week, hospital-based, out-patient PR. Baseline and post-PR status were evaluated by spirometry, the St George's Respiratory Questionnaire, cardiopulmonary exercise test, respiratory muscle strength, and dyspnea scores. The mean FEV1 in the subjects was 1.29 ± 0.47 L/min, 64.8 ± 23.0% of predicted. After PR there was significant improvement in maximal oxygen uptake and work rate. Improvements in St George's Respiratory Questionnaire scores of total, symptoms, activity, and impact were accompanied by improvements of exercise capacity, respiratory muscle strength, maximum oxygen pulse, and exertional dyspnea scores (all P < .05). There were no significant changes in pulmonary function test results (FEV1, FVC, and FEV1/FVC), minute ventilation, breathing frequency, or tidal volume at rest or exercise after PR. Exercise training can result in significant improvement in health-related quality of life, exercise capacity, respiratory muscle strength, and exertional dyspnea in subjects with COPD and normal exercise capacity. Exercise training is still indicated for patients with normal exercise capacity.

The "Chaos Theory" and nonlinear dynamics in heart rate variability analysis: does it work in short-time series in patients with coronary heart disease?

PubMed

Krstacic, Goran; Krstacic, Antonija; Smalcelj, Anton; Milicic, Davor; Jembrek-Gostovic, Mirjana

2007-04-01

Dynamic analysis techniques may quantify abnormalities in heart rate variability (HRV) based on nonlinear and fractal analysis (chaos theory). The article emphasizes clinical and prognostic significance of dynamic changes in short-time series applied on patients with coronary heart disease (CHD) during the exercise electrocardiograph (ECG) test. The subjects were included in the series after complete cardiovascular diagnostic data. Series of R-R and ST-T intervals were obtained from exercise ECG data after sampling digitally. The range rescaled analysis method determined the fractal dimension of the intervals. To quantify fractal long-range correlation's properties of heart rate variability, the detrended fluctuation analysis technique was used. Approximate entropy (ApEn) was applied to quantify the regularity and complexity of time series, as well as unpredictability of fluctuations in time series. It was found that the short-term fractal scaling exponent (alpha(1)) is significantly lower in patients with CHD (0.93 +/- 0.07 vs 1.09 +/- 0.04; P < 0.001). The patients with CHD had higher fractal dimension in each exercise test program separately, as well as in exercise program at all. ApEn was significant lower in CHD group in both RR and ST-T ECG intervals (P < 0.001). The nonlinear dynamic methods could have clinical and prognostic applicability also in short-time ECG series. Dynamic analysis based on chaos theory during the exercise ECG test point out the multifractal time series in CHD patients who loss normal fractal characteristics and regularity in HRV. Nonlinear analysis technique may complement traditional ECG analysis.

Cardio-respiratory and plasma lactate responses to exercise with low draught resistances in standardbred trotters.

PubMed

Gottlieb-Vedi, M; Essén-Gustavsson, B; Lindholm, A

1996-12-01

Five Standardbred trotters performed treadmill exercise with incrementally increasing trotting velocities for 2 min intervals in three different tests until fatigue. Each test was performed with draught loads of either 10, 20 or 30 kilopond (kp). Each trotting interval was followed by 2 min periods at a walk without draught load. Recordings were made of heart rate (HR), respiratory rate (RR), plasma lactate (PLA) and stride frequency (SF) at the end of each trotting interval. The HR increased to average values of 191 +/- 10,203 +/- 10 and 214 +/- 7 bpm and PLA increased to 3.8 +/- 0.7, 7.3 +/- 3.8 and 10.8 +/- 6.4 mmol/l at 9 m/s in the three tests, respectively. The HR response to exercise was significantly higher with increasing draught loads, and PLA was significantly higher with 30 kp compared to 10 kp draught resistance. The lowest respiratory rate was seen in the test with 30 kp loading. Peak oxygen uptake (VO2peak) was measured in a separate test on a sloped treadmill with increasing velocities without draught load and averaged 70.4 +/- 9.11/min. Muscle biopsies were taken from the gluteus muscle. Individual variations were seen in VO2peak, muscle fibre composition and HR and PLA responses to exercise. In conclusion, at a certain velocity a small increase in draught resistance from 10 to 30 kp significantly increases both the HR and PLA responses. At comparable work intensities the horses differed in circulatory and metabolic responses to exercise.

Mindful2Work: Effects of Combined Physical Exercise, Yoga, and Mindfulness Meditations for Stress Relieve in Employees. A Proof of Concept Study.

PubMed

de Bruin, Esther I; Formsma, Anne R; Frijstein, Gerard; Bögels, Susan M

2017-01-01

Work-related stress and associated illness and burnout is rising in western society, with now as much as almost a quarter of European and half of USA's employees estimated to be at the point of burnout. Mindfulness meditation, yoga, and physical exercise have all shown beneficial effects for work-related stress and illness. This proof of concept study assessed the feasibility, acceptability, and preliminary effects of the newly developed Mindful2Work training, a combination of physical exercise, restorative yoga, and mindfulness meditations, delivered in six weekly group sessions plus a follow-up session. Participants ( n  = 26, four males), referred by company doctors with (work-related) stress and burnout complaints, completed measurements pre and post the intervention, as well as at 6-week (FU1) and 6-month (FU2) follow-up. Results showed very high feasibility and acceptability of the Mindful2Work training. The training and trainers were rated with an 8.1 and 8.4 on a 1-10 scale, respectively, and training dropout rate was zero. Significant improvements with (very) large effect sizes were demonstrated for the primary outcome measures of physical and mental workability, and for anxiety, depression, stress, sleep quality, positive and negative affect, which remained (very) large and mostly increased further over time. Risk for long-term dropout from work (checklist individual strength [CIS]) was 92 % at pre-test, reduced to 67 % at post-test, to 44 % at FU1, and 35 % at FU2, whereas employees worked (RTWI) 65 % of their contract hours per week at pre-test, which increased to 73 % at post-test, 81 % at FU1 and 93 % at FU2. Intensity of home practice or number of attended sessions were not related to training effects. To conclude, the newly developed Mindful2Work training seems very feasible, and acceptable, and although no control group was included, the large effects of Mindful2Work are highly promising.

[Status quo of lifestyle among women of five occupations in six provinces of China].

PubMed

Pang, Jing; Li, Ying-hua; Yang, Chong; Nie, Xue-qiong; Tao, Mao-xuan

2012-10-01

To learn the status quo of lifestyle among women of five occupations in six provinces of China. A questionnaire was administered among 7416 women from five occupations (civil servants, teachers of elementary and high schools, technical staff, enterprise managers and physical laborers) in Beijing, Hebei, Jilin, Hubei, Ningxia and Gansu of China. The sample was selected by multi-stage stratified cluster random sampling method from December 2009 to June 2010. The questionnaire information included demographic characteristics, diet, sleep habit, smoking, physical exercise. The χ(2) test was used to analyze the different in life style of different occupations. There were 7416 valid questionnaires received, and the valid rate of the questionnaires was 97.58% (7416/7682). About 38.00% (2818/7416) respondents preferred to bland diet and 28.44% (2109/7416) preferred to salty and oily food and 33.56% (2489/7416) had no preference. The proportion of sleep time between seven and eight hours per day was highest (accounting for 56.23%, 4154/7416), 25.27% (1867/7416) with sleep time less than seven hours. Among the population who had the sleep time less seven hours, teacher that had the highest rate accounted for 33.19% (531/1607) and technical staff had the lowest rate accounted for 21.05% (301/1401) (P < 0.01). Most of respondents were non-smokers, accounting for 93.10% (6869/7416). 22.73% (1671/7416) respondents passively smoked. The proportion of always passive smoking was highest among civil servants and lowest among teachers, accounting for 26.60% (404/1531) and 18.71% (298/1607), respectively. The proportion of having no physical exercises was highest, accounting for 62.87% (4637/7416). The proportion of having three times physical exercises per week was 12.68% (935/7416). The proportion of having no physical exercises among physical laborers (66.42%, 912/1386), enterprise managers (66.64%, 987/1491) and teachers (62.40%, 999/1607) were higher than others and the proportion of having physical exercises per week among technical staff was 40.83% (569/1401), higher than others (P < 0.01). The proportion of person who worked in sitting quietly beyond six hours per day was 42.62% (3146/7416). The technical staff had the higher rate than other occupational populations (P < 0.01), accounting for 57.83% (809/1401). The female occupational population had some unhealthy lifestyles, such as taking in high salt food, lacking of sleep, smoking and passive smoking, lacking of physical exercises and working in sitting quietly. Different occupational populations had different unhealthy lifestyles.

Metabolic rate measurements comparing supine with upright upper-body exercises

NASA Technical Reports Server (NTRS)

Fortney, Suzanne M.; Greenisen, Michael C.; Loftin, Karin C.; Beene, Donya; Freeman-Perez, Sondra; Hnatt, Linda

1993-01-01

The ground-based study that tested the hypothesis that metabolic rates during supine and upright upper-body exercises are similar (mean value of 200 kcal/h) is presented. Six subjects each performed supine or upright exercise at three exercise stations, a hand-cycle ergometer, a rope-pull device, and a torque wrench. After a baseline measurement of the metabolic rate at rest, the metabolic rate was measured twice at each exercise station. The mean metabolic rates (kcal/h) during supine (n = 6) and upright control (n = 4) exercise stations were not significantly different except for the rope-pull station, 153.5 +/- 16.6 (supine) as compared to 247.0 +/- 21.7 (upright), p is less than 0.05. This difference may be due in part to an increased mechanical efficiency of supine exercises (15.0 +/- 0.7 percent) as compared to that of upright exercises (11.0 +/- 1.08 percent), p is less than 0.05. The net energy input was significantly smaller for the supine rope-pull exercise (64 +/- 18) as compared to upright (176 +/- 20). The relationship between best-rest exercises, metabolic rates, and the incidence of decompression sickness (DCS) should be examined to determine the true risk of DCS in spaceflight extravehicular activities.

Distribution and predictors of exercise habits among pregnant women in the Danish National Birth Cohort.

PubMed

Juhl, M; Madsen, M; Andersen, A-M N; Andersen, P K; Olsen, J

2012-02-01

Physical activity is recommended during pregnancy, although strong evidence on reproductive health is lacking. We present exercise habits and predictors of exercise during pregnancy. From the Danish National Birth Cohort (1996-2002), 88,200 singleton pregnancies were analyzed in logistic regression. About one-third of the women exercised in early/mid pregnancy and slightly less in late pregnancy. Bicycling, swimming, and low-impact activities were most common. Exercising more than three times per week was strongly correlated with older age, being a student or out of work, eating disorders, moderate alcohol consumption, and a healthy diet. Multiparity, a normal or less good self-rated health, smoking, and a less health conscious diet were the strongest predictors of not doing exercise. Women of 25 years or older, with metabolic or psychiatric disorders, or who had received subfecundity treatment were more likely to increase their activity level substantially from early to late pregnancy than comparison groups. In conclusion, exercising during pregnancy correlated with a number of maternal characteristics. The findings may be used to identify pregnant women not likely to exercise, to target activities that may fit their needs, and, for research purposes, to identify adjustment variables or guide sensitivity analyses when data on confounders are lacking. © 2010 John Wiley & Sons A/S.

An Introductory Interprofessional Exercise for Healthcare Students

PubMed Central

Rege, Saumitra V.; Misto, Kara; Dollase, Richard; George, Paul

2012-01-01

Objective. To evaluate healthcare students’ perceptions of an introductory interprofessional exercise and their team dynamics. Design. A workshop was developed, combining second-year medical students, fourth-year nursing students, and third-year pharmacy students to work as an interdisciplinary team. The teams alternated between working together on patient cases focusing on chronic obstructive pulmonary disease and asthma, and on the evaluation of standardized pneumonia patients. Teams were given the patients' health information and no other instructions. A faculty member and the standardized patient evaluated the students using a teamwork global rating scale. Assessment. Student survey results showed a positive response to interprofessional teamwork. The faculty members and standardized patients reported that the students worked as a cohesive unit and demonstrated good team communication. Conclusions. This introductory interprofessional experience had a positive impact on the students’ understanding of collaboration and teamwork. This type of experience will help students foster future collaborations as healthcare providers. PMID:23129853

Clinical Effects of a Dietary Antioxidant Silicate Supplement, Microhydrin((R)), on Cardiovascular Responses to Exercise.

PubMed

Purdy Lloyd, Kimberly L.; Wasmund, Wendy; Smith, Leonard; Raven, Peter B.

2001-01-01

Amorphous silicate minerals, often described as rock flour, were once common in natural water sources and abundant in glacial stream waters. Not only do the silica mineral particles bond water and other elements for transport; they also can be adsorbed with reduced hydrogen, which releases electrons, providing antioxidant or reducing potential to surrounding fluids. The purpose of this investigation was to examine the cardiovascular responses during exercise after consumption of a dietary silicate mineral antioxidant supplement, Microhydrin((R)) (Royal BodyCare, Inc., Irving, TX). A clinical trial incorporating a double-blind, placebo-controlled, crossover experimental design was employed. Subjects received either active agent or placebo, four capsules per day, for 7 days before the trial. The trial evaluated six exercise bicycle-trained subjects performing a 40-km bicycling time trial. Ratings of perceived exertion and measurements of oxygen uptake, heart rate, performance workload, and preexercise and postexercise blood lactate concentrations were obtained. Although there were no differences (P >/=.05) in work performed, heart rate, oxygen uptake, and ratings of perceived exertion during the time trial, the postexercise blood lactate concentrations were significantly lower (P

Association of heart rate profile during exercise with the severity of coronary artery disease.

PubMed

Cay, Serkan; Ozturk, Sezgin; Biyikoglu, Funda; Yildiz, Abdulkadir; Cimen, Tolga; Uygur, Belma; Tuna, Funda

2009-05-01

Coronary artery disease is the leading cause of morbidity and mortality around the world. Autonomic nervous system abnormalities are associated with coronary artery disease and its complications. Exercise stress tests are routinely used for the detection of the presence of coronary artery disease. In this study, we observed the association between heart rate profile during exercise and the severity of coronary artery disease. One hundred and sixty patients with abnormal exercise treadmill test (> or =1 mm horizontal or downsloping ST-segment depression; 119 men, 41 women; mean age = 57 +/- 9 years) were included in the study. Use of any drug affecting heart rate was not permitted. Resting heart rate before exercise, maximum heart rate during exercise, and resting heart rate after exercise (5 min later) were measured and two parameters were calculated: heart rate increment (maximum heart rate - resting heart rate before exercise) and heart rate decrement (maximum heart rate - resting heart rate after exercise). All patients underwent selective coronary angiography and subclassified into two groups according to stenotic lesion severity. Group 1 had at least 50% of stenotic lesion and group 2 had less than 50%. Patients in the first group had increased resting heart rate, decreased maximum heart rate, decreased heart rate increment, and decreased heart rate decrement compared with second group. All patients were classified into tertiles of resting heart rate, heart rate increment, and heart rate decrement level to evaluate whether these parameters were associated with severity of coronary artery stenosis in the study. The multiple-adjusted odds ratio of the risk of severe coronary atherosclerosis was 21.888 (95% confidence interval 6.983-68.606) for the highest tertile of resting heart rate level compared with the lowest tertile. In addition, the multiple-adjusted odds ratio of the risk of severe coronary atherosclerosis was 20.987 (95% confidence interval 6.635-66.387) for the lowest tertile of heart rate increment level compared with the highest tertile and 2.360 (95% confidence interval 1.004-5.544) for the lowest tertile of heart rate decrement level compared with the highest tertile. Altered autonomic nervous system regulation affects heart rate profile, increased resting heart rate, decreased heart rate increment, and decreased heart rate decrement, during exercise and this effect is strongly and independently associated with the severity of coronary artery disease.

Longitudinal associations between exercise identity and exercise motivation: A multilevel growth curve model approach.

PubMed

Ntoumanis, N; Stenling, A; Thøgersen-Ntoumani, C; Vlachopoulos, S; Lindwall, M; Gucciardi, D F; Tsakonitis, C

2018-02-01

Past work linking exercise identity and exercise motivation has been cross-sectional. This is the first study to model the relations between different types of exercise identity and exercise motivation longitudinally. Understanding the dynamic associations between these sets of variables has implications for theory development and applied research. This was a longitudinal survey study. Participants were 180 exercisers (79 men, 101 women) from Greece, who were recruited from fitness centers and were asked to complete questionnaires assessing exercise identity (exercise beliefs and role-identity) and exercise motivation (intrinsic, identified, introjected, external motivation, and amotivation) three times within a 6 month period. Multilevel growth curve modeling examined the role of motivational regulations as within- and between-level predictors of exercise identity, and a model in which exercise identity predicted exercise motivation at the within- and between-person levels. Results showed that within-person changes in intrinsic motivation, introjected, and identified regulations were positively and reciprocally related to within-person changes in exercise beliefs; intrinsic motivation was also a positive predictor of within-person changes in role-identity but not vice versa. Between-person differences in the means of predictor variables were predictive of initial levels and average rates of change in the outcome variables. The findings show support to the proposition that a strong exercise identity (particularly exercise beliefs) can foster motivation for behaviors that reinforce this identity. We also demonstrate that such relations can be reciprocal overtime and can depend on the type of motivation in question as well as between-person differences in absolute levels of these variables. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Analyzing Exercise Training Effect and Its Impact on Cardiorespiratory and Cardiovascular Fitness

ERIC Educational Resources Information Center

Laumakis, Paul J.; McCormack, Kevin

2014-01-01

This paper provides a statistical investigation of the impact of heart rate levels on training effect for a specific exercise regimen, including an analysis of post-exercise heart rate recovery. Results indicate optimum target values for both average and maximum heart rate during exercise in order to improve both cardiorespiratory and…

Dietary sodium and plasma volume levels with exercise.

PubMed

Luetkemeier, M J; Coles, M G; Askew, E W

1997-05-01

Sodium is the major cation of the extracellular fluid and has a potent influence on fluid movement. Sodium has been likened to a sponge that draws fluids into the extracellular space, including the plasma volume, to equalize gradients in concentration. Conventional wisdom suggests limiting dietary intake of Na+ to decrease risk of hypertension. However, there are some extreme occupational or exercise-related conditions where sweat losses are great and Na+ losses may exceed normal dietary intake. This can occur acutely such as in an ultra-endurance event or chronically as in hard manual work in the hear. In such cases, additional Na+ in the form of a higher Na+ diet or adding Na+ to beverages used for fluid replacement may be warranted. A higher Na+ diet also appears to accelerate the cardiovascular and thermoregulatory adaptations that accompany heat acclimation or short term exercise training. Saline ingestion before exercise causes an expansion of plasma volume at rest and throughout the subsequent exercise bout. This expansion of plasma volume alters cardiovascular and thermoregulatory responses to exercise in ways that may lead to beneficial changes in endurance exercise performance. Plasma volume expansion also occurs with saline infusion during exercise, but exercise performance advantages have yet to be reported. The purpose of this article is to review the literature concerning dietary sodium and its influence on fluid balance, plasma volume and thermoregulation during exercise. It contains 2 major sections. First, we will discuss manipulations in daily Na+ intake initiated before or throughout an exercise regime. Second, we will examine studies where an acute Na+ load was administered immediately before or during an exercise trial. The dependent variables that we will discuss pertain to: (i) body water compartments, i.e. plasma volume; (ii) thermoregulatory variables, i.e. core temperature and sweat rate; (iii) cardiovascular variables, i.e. heart rate and stroke volume; and (iv) performance, i.e. time trial performance and time to exhaustion. Particular attention will be given to the route by which Na+ was administered, the environmental conditions, the level of acclimation of the participants and specifics relating to Na+ administration such as the osmolality of the Na(+)-containing beverage.

Design of a consensus-derived synoptic operative report for lung cancer surgery.

PubMed

Schneider, Laura; Shargall, Yaron; Schieman, Colin; Seely, Andrew J; Srinathan, Sadeesh; Malthaner, Richard A; Pierre, Andrew F; Safieddine, Najib; Vaillancourt, Rosaire; Plourde, Madelaine; Bond, James; Johnson, Scott; Smith, Shona E; Finley, Christian J

2014-04-01

For lung cancer surgery, a narrative operative report is the standard reporting procedure, whereas a synoptic-style report is increasingly utilized by healthcare professionals in various specialties with great success. A synoptic operative report more succinctly and accurately captures vital information and is rapidly generated with good intraobserver reliability. The objective of this study was to systematically develop a synoptic operative report for lung cancer surgery following a modified Delphi consensus model with the support of the Canadian thoracic surgery community. Using online survey software, thoracic surgeons and related physicians were asked to suggest and rate data elements for a synoptic report following the modified Delphi consensus model. The consensus exercise-derived template was forwarded to a small working group, who further refined the definition and priority designation of elements until the working group had reached a satisfactory consensus. In all, 139 physicians were invited to participate in the consensus exercise, with 36.7%, 44.6%, and 19.5% response rates, respectively, in the three rounds. Eighty-nine elements were agreed upon at the conclusion of the exercise, but 141 elements were forwarded to the working group. The working group agreed upon a final data set of 180 independently defined data elements, with 72 mandatory and 108 optional elements for implementation in the final report. This study demonstrates the process involved in developing a multidisciplinary, consensus-based synoptic lung cancer operative report. This novel report style is a quality improvement initiative to improve the capture, dissemination, readability, and potential utility of critical surgical information. Copyright © 2014 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Junior Army Officer Retention Intentions: A Path Analytic Model

DTIC Science & Technology

1991-07-01

theoretically useful only if they explain behavior that cannot be predicted within traditional expectancy and equity based motivational models. Scholl (1981), in...argue that long-tenured employees need to justify their behavioral commitment to the organization. They do this by developing more positive attitudes...good" to "very poor" scale to rate opportunities for intrinsic work satisfaction (learn/ develop skills, do interesting work, exercise initiative) in

Influence of energy drinks and alcohol on post-exercise heart rate recovery and heart rate variability.

PubMed

Wiklund, Urban; Karlsson, Marcus; Oström, Mats; Messner, Torbjörn

2009-01-01

Media have anecdotally reported that drinking energy drinks in combination with alcohol and exercise could cause sudden cardiac death. This study investigated changes in the electrocardiogram (ECG) and heart rate variability after intake of an energy drink, taken in combination with alcohol and exercise. Ten healthy volunteers (five men and five women aged 19-30) performed maximal bicycle ergometer exercise for 30 min after: (i) intake of 0.75 l of an energy drink mixed with alcohol; (ii) intake of energy drink; and, (iii) no intake of any drink. ECG was continuously recorded for analysis of heart rate variability and heart rate recovery. No subject developed any clinically significant arrhythmias. Post-exercise recovery in heart rate and heart rate variability was slower after the subjects consumed energy drink and alcohol before exercise, than after exercise alone. The healthy subjects developed blunted cardiac autonomic modulation after exercising when they had consumed energy drinks mixed with alcohol. Although they did not develop any significant arrhythmia, individuals predisposed to arrhythmia by congenital or other rhythm disorders could have an increased risk for malignant cardiac arrhythmia in similar situations.

Not sending the message: A low prevalence of strength-based exercise participation in rural and regional Central Queensland.

PubMed

Dalbo, Vincent J; Czerepusko, James B; Tucker, Patrick S; Kingsley, Michael I; Moon, Jordan R; Young, Kaelin; Scanlan, Aaron T

2015-10-01

The primary aim of this study was to determine the prevalence of current strength-based exercise in rural and regional populations of Central Queensland. The secondary aim was to examine the proportion of residents from various demographic groups who currently partake in strength-based exercise to allow for targeted strength training campaigns. A cross-sectional, survey-based experimental design was followed. Rural and regional Australia. Rural and regional community-dwelling individuals living in Central Queensland and aged 18 years and older. Survey data was collected in October and November 2010 as part of the Central Queensland University Social Survey. Strength-based exercise participation, gender, age, income, years of education, self-reported physical activity and perception of health. Participation in strength-based exercise was 13.2%. Women were less likely to partake in strength-based exercise than male, and ≥55 year old adults were less likely to partake in strength-based exercise than 18-34 year old adults. Participation in strength-based exercise was found to increase with years of education, self-reported physical activity and self-rated health. The prevalence of adults in rural and regional Central Queensland engaging in strength-based exercise is low. Exercise physiologists, clinicians and government officials must work together to ensure that this form of exercise is acknowledged as a vital component of health in rural and regional areas. © 2015 National Rural Health Alliance Inc.

Feasibility and safety of virtual-reality-based early neurocognitive stimulation in critically ill patients.

PubMed

Turon, Marc; Fernandez-Gonzalo, Sol; Jodar, Mercè; Gomà, Gemma; Montanya, Jaume; Hernando, David; Bailón, Raquel; de Haro, Candelaria; Gomez-Simon, Victor; Lopez-Aguilar, Josefina; Magrans, Rudys; Martinez-Perez, Melcior; Oliva, Joan Carles; Blanch, Lluís

2017-12-01

Growing evidence suggests that critical illness often results in significant long-term neurocognitive impairments in one-third of survivors. Although these neurocognitive impairments are long-lasting and devastating for survivors, rehabilitation rarely occurs during or after critical illness. Our aim is to describe an early neurocognitive stimulation intervention based on virtual reality for patients who are critically ill and to present the results of a proof-of-concept study testing the feasibility, safety, and suitability of this intervention. Twenty critically ill adult patients undergoing or having undergone mechanical ventilation for ≥24 h received daily 20-min neurocognitive stimulation sessions when awake and alert during their ICU stay. The difficulty of the exercises included in the sessions progressively increased over successive sessions. Physiological data were recorded before, during, and after each session. Safety was assessed through heart rate, peripheral oxygen saturation, and respiratory rate. Heart rate variability analysis, an indirect measure of autonomic activity sensitive to cognitive demands, was used to assess the efficacy of the exercises in stimulating attention and working memory. Patients successfully completed the sessions on most days. No sessions were stopped early for safety concerns, and no adverse events occurred. Heart rate variability analysis showed that the exercises stimulated attention and working memory. Critically ill patients considered the sessions enjoyable and relaxing without being overly fatiguing. The results in this proof-of-concept study suggest that a virtual-reality-based neurocognitive intervention is feasible, safe, and tolerable, stimulating cognitive functions and satisfying critically ill patients. Future studies will evaluate the impact of interventions on neurocognitive outcomes. Trial registration Clinical trials.gov identifier: NCT02078206.

Validation of the Pulmonary Function System for Use on the International Space Station

NASA Technical Reports Server (NTRS)

McCleary, Frank A.; Moore, Alan D., Jr.; Hagan, R. Donald

2007-01-01

Aerobic deconditioning occurs during long duration space flight despite the use of exercise countermeasures (Convertino, 1996). As a part of International Space Station (ISS) medical operations, periodic tests designed to estimate aerobic capacity are performed to track changes in aerobic fitness and to determine the effectiveness of exercise countermeasures. These tests are performed prior to, during, and after missions of greater than 30 days in duration. Crewmembers selected for missions aboard the ISS perform a graded exercise test on a cycle ergometer approximately 270 days prior to their scheduled launch date in order to measure peak oxygen consumption (VO2PK) and peak heart rate (HRpk). Approximately 30 to 45 days prior to launch, crewmembers perform a submaximal cycle ergometer test at work rates set to elicit 25, 50 and 75% of their pre-flight VO2PK. This test, known as the Periodic Fitness Evaluation (PFE), serves as a baseline measure to which subsequent in-and post-flight exercise tests are compared. While onboard the ISS, crewmembers are normally scheduled to perform the PFE beginning with flight day (FD) 14 and every 30 days thereafter. The PFE is also conducted 5 and 30 days following flight. Using PFE data, aerobic fitness is estimated by quantifying the VO2 vs. HR relationship using linear regression and calculating the VO2 that would occur at the crewmember s previously measured HRpk. Currently, for data collected during flight, this technique assumes that the pre- vs. in-flight oxygen consumption per given cycle workload is similar. However, the validity of this assumption is based upon a sparse amount of data collected during the Skylab era (Michel, et al. 1977). The method of using heart rate and cycle ergometer work rates has been used to estimate aerobic fitness in normal gravity (Astrand and Ryhming, 1954; Lee, 1993). Due to spaceflight induced physiological alterations, such as shifts in extracellular fluid (e.g. plasma) volume, this method may not be valid during space flight. In addition, the ergometer onboard ISS is vibration-isolated and moves with the astronaut s application of force into the pedals. The effect of this movement on the VO2 of cycle exercise on ISS has not been quantified.

Effects of 12 weeks combined aerobic and resistance exercise on heart rate variability in type 2 diabetes mellitus patients.

PubMed

Kang, Seol-Jung; Ko, Kwang-Jun; Baek, Un-Hyo

2016-07-01

[Purpose] This study evaluated the effects of 12 weeks combined aerobic and resistance exercise on heart rate variability in patients with Type 2 diabetes mellitus. [Subjects and Methods] The subjects were 16 female patients with Type 2 diabetes mellitus selected among the participants of a chronic disease management exercise class at C Region Public Health Center in South Korea. Subjects were randomly assigned to the exercise group (n=8; age, 55.97 ± 7.37) or the control group (n=8; age, 57.53 ± 4.63) The exercise group performed aerobic and resistance exercises for 60 minutes per day, 3 times per week for 12 weeks. Anthropometric measurements, biochemical markers, physical fitness, and heart rate variability were examined. [Results] After 12 weeks of exercise, weight, body fat percentage, waist circumference, blood glucose, insulin resistance, glycated hemoglobin level, systolic blood pressure, and diastolic blood pressure significantly decreased and cardiorespiratory fitness and muscular strength significantly increased in the exercise group. Although heart rate variability measures showed favorable changes with the exercise program, none were significant. [Conclusion] Although the exercise program did not show notable changes in heart rate variability in patients with Type 2 diabetes within the timeframe of the study, exercise may contribute to the prevention and control of cardiovascular autonomic neuropathy.

Space exercise and Earth benefits.

PubMed

Macias, Brandon R; Groppo, Eli R; Eastlack, Robert K; Watenpaugh, Donald E; Lee, Stuart M C; Schneider, Suzanne M; Boda, Wanda L; Smith, Scott M; Cutuk, Adnan; Pedowitz, Robert A; Meyer, R Scott; Hargens, Alan R

2005-08-01

The detrimental impact of long duration space flight on physiological systems necessitates the development of exercise countermeasures to protect work capabilities in gravity fields of Earth, Moon and Mars. The respective rates of physiological deconditioning for different organ systems during space flight has been described as a result of data collected during and after missions on the Space Shuttle, International Space Station, Mir, and bed rest studies on Earth. An integrated countermeasure that simulates the body's hydrostatic pressure gradient, provides mechanical stress to the bones and muscles, and stimulates the neurovestibular system may be critical for maintaining health and well being of crew during long-duration space travel, such as a mission to Mars. Here we review the results of our studies to date of an integrated exercise countermeasure for space flight, lower body negative pressure (LBNP) treadmill exercise, and potential benefits of its application to athletic training on Earth. Additionally, we review the benefits of Lower Body Positive Pressure (LBPP) exercise for rehabilitation of postoperative patients. Presented first are preliminary data from a 30-day bed rest study evaluating the efficacy of LBNP exercise as an integrated exercise countermeasure for the deconditioning effects of microgravity. Next, we review upright LBNP exercise as a training modality for athletes by evaluating effects on the cardiovascular system and gait mechanics. Finally, LBPP exercise as a rehabilitation device is examined with reference to gait mechanics and safety in two groups of postoperative patients.

Circulatory and muscle metabolic responses to draught work compared to increasing trotting velocities.

PubMed

Gottlieb, M; Essén-Gustavsson, B; Lindholm, A; Persson, S G

1988-11-01

Circulatory and muscle metabolic responses were studied in 10 horses which all performed incremental draught work at a low trotting speed on a treadmill (D-test) and also exercise with gradually increasing velocities (S-test). Exercise was continued until the horses could no longer maintain the weights above the floor or maintain speed trotting without changing gait to a gallop. Muscle biopsies were taken from the gluteus and the semitendinosus muscles before, and immediately after, exercise. The heart rate (HR) increased linearly with both increasing draught resistance and velocity and reached mean values of 212 and 203 beats/min, respectively. Blood lactate levels increased exponentially to mean values of 12.9 and 7.9 mmol/litre in the two tests. Both HR and blood lactate levels were significantly higher at the cessation of work in the D-test compared to the S-test. The relationship between HR and blood lactate response in the S-test was similar to that in the D-test. The red cell volume was determined after a standardised exercise tolerance test and was significantly correlated both to the weightloading and to the velocity, producing a HR of 200 beats/min. The changes seen in muscle glycogen and glucose-6-phosphate were similar in the two tests, whereas significantly higher lactate levels and lower creatine phosphate and adenosine triphosphate levels were seen in the D-test compared to the S-test. It was concluded that high oxidative capacity is of importance both for fast trotting and for draught work.(ABSTRACT TRUNCATED AT 250 WORDS)

Diagnostic accuracy of heart-rate recovery after exercise in the assessment of diabetic cardiac autonomic neuropathy.

PubMed

Sacre, J W; Jellis, C L; Coombes, J S; Marwick, T H

2012-09-01

Poor prognosis associated with blunted post-exercise heart-rate recovery may reflect autonomic dysfunction. This study sought the accuracy of post-exercise heart-rate recovery in the diagnosis of cardiac autonomic neuropathy, which represents a serious, but often unrecognized complication of Type 2 diabetes. Clinical assessment of cardiac autonomic neuropathy and maximal treadmill exercise testing for heart-rate recovery were performed in 135 patients with Type 2 diabetes and negative exercise echocardiograms. Cardiac autonomic neuropathy was defined by abnormalities in ≥ 2 of 7 autonomic function markers, including four cardiac reflex tests and three indices of short-term (5-min) heart-rate variability. Heart-rate recovery was defined at 1-, 2- and 3-min post-exercise. Patients with cardiac autonomic neuropathy (n = 27; 20%) had lower heart-rate recovery at 1-, 2- and 3-min post-exercise (P < 0.01). Heart-rate recovery demonstrated univariate associations with autonomic function markers (r-values 0.20-0.46, P < 0.05). Area under the receiver-operating characteristic curve revealed good diagnostic performance of all heart-rate recovery parameters (range 0.80-0.83, P < 0.001). Optimal cut-offs for heart-rate recovery at 1-, 2- and 3-min post-exercise were ≤ 28 beats/min (sensitivity 93%, specificity 69%), ≤ 50 beats/min (sensitivity 96%, specificity 63%) and ≤ 52 beats/min (sensitivity 70%, specificity 84%), respectively. These criteria predicted cardiac autonomic neuropathy independently of relevant clinical and exercise test information (adjusted odds ratios 7-28, P < 0.05). Post-exercise heart-rate recovery provides an accurate diagnostic test for cardiac autonomic neuropathy in Type 2 diabetes. The high sensitivity and modest specificity suggests heart-rate recovery may be useful to screen for patients requiring clinical autonomic evaluation. © 2012 The Authors. Diabetic Medicine © 2012 Diabetes UK.

T wave alternans during exercise and atrial pacing in humans

NASA Technical Reports Server (NTRS)

Hohnloser, S. H.; Klingenheben, T.; Zabel, M.; Li, Y. G.; Albrecht, P.; Cohen, R. J.

1997-01-01

INTRODUCTION: Evidence is accumulating that microvolt T wave alternans (TWA) is a marker of increased risk for ventricular tachyarrhythmias. Initially, atrial pacing was used to elevate heart rate and elicit TWA. More recently, a noninvasive approach has been developed that elevates heart rate using exercise. METHODS AND RESULTS: In 30 consecutive patients with a history of ventricular tachyarrhythmias, the spectral method was used to detect TWA during both atrial pacing and submaximal exercise testing. The concordance rate for the presence or absence of TWA using the two measurement methods was 84%. There was a patient-specific heart rate threshold for the detection of TWA that averaged 100 +/- 14 beats/min during exercise compared with 97 +/- 9 beats/min during right atrial pacing (P = NS). Beyond this threshold, there was a significant and comparable increase in level of TWA with decreasing pacing cycle length and increasing exercise heart rates. CONCLUSIONS: The present study is the first to demonstrate that microvolt TWA can be assessed reliably and noninvasively during exercise stress. There is a patient-specific heart rate threshold beyond which TWA continues to increase with increasing heart rates. Heart rate thresholds for the onset of TWA measured during atrial pacing and exercise stress were comparable, indicating that heart rate alone appears to be the main factor of determining the onset of TWA during submaximal exercise stress.

Respiratory weight losses during exercise.

NASA Technical Reports Server (NTRS)

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

1972-01-01

Evaporative water loss from the respiratory tract was determined over a wide range of exercise. The absolute humidity of the expired air was the same at all levels of exercise and equal to that measured at rest. The rate of respiratory water loss during exercise was found to be 0.019 of the oxygen uptake times (44 minus water vapor pressure). The rate of weight loss during exercise due to CO2-O2 exchange was calculated. For exercise at oxygen consumption rates exceeding 1.5 L/min in a dry environment with a water vapor pressure of 10 mm Hg, the total rate of weight loss via the respiratory tract is on the order of 2-5 g/min.

A five-week exercise program can reduce falls and improve obstacle avoidance in the elderly.

PubMed

Weerdesteyn, Vivian; Rijken, Hennie; Geurts, Alexander C H; Smits-Engelsman, Bouwien C M; Mulder, Theo; Duysens, Jacques

2006-01-01

Falls in the elderly are a major health problem. Although exercise programs have been shown to reduce the risk of falls, the optimal exercise components, as well as the working mechanisms that underlie the effectiveness of these programs, have not yet been established. To test whether the Nijmegen Falls Prevention Program was effective in reducing falls and improving standing balance, balance confidence, and obstacle avoidance performance in community-dwelling elderly people. A total of 113 elderly with a history of falls participated in this study (exercise group, n = 79; control group, n = 28; dropouts before randomization, n = 6). Exercise sessions were held twice weekly for 5 weeks. Pre- and post-intervention fall monitoring and quantitative motor control assessments were performed. The outcome measures were the number of falls, standing balance and obstacle avoidance performance, and balance confidence scores. The number of falls in the exercise group decreased by 46% (incidence rate ratio (IRR) 0.54, 95% confidence interval (CI) 0.36-0.79) compared to the number of falls during the baseline period and by 46% (IRR 0.54, 95% CI 0.34-0.86) compared to the control group. Obstacle avoidance success rates improved significantly more in the exercise group (on average 12%) compared to the control group (on average 6%). Quiet stance and weight-shifting measures did not show significant effects of exercise. The exercise group also had a 6% increase of balance confidence scores. The Nijmegen Falls Prevention Program was effective in reducing the incidence of falls in otherwise healthy elderly. There was no evidence of improved control of posture as a mechanism underlying this result. In contrast, an obstacle avoidance task indicated that subjects improved their performance. Laboratory obstacle avoidance tests may therefore be better instruments to evaluate future fall prevention studies than posturographic balance assessments. Copyright (c) 2006 S. Karger AG, Basel.

Fitting a single-phase model to the post-exercise changes in heart rate and oxygen uptake.

PubMed

Stupnicki, R; Gabryś, T; Szmatlan-Gabryś, U; Tomaszewski, P

2010-01-01

The kinetics of post-exercise heart rate (HR) and oxygen consumption (EPOC) was studied in 10 elite cyclists subjected to four laboratory cycle ergometer maximal exercises lasting 30, 90, 180 or 360 s. Heart rate and oxygen uptake (VO2) were recorded over a period of 6 min after the exercise. By applying the logit transformation to the recorded variables and relating them to the decimal logarithm of the recovery time, uniform single-phase courses of changes were shown for both variables in all subjects and exercises. This enabled computing half-recovery times (t(1/2)) for both variables. Half-time for VO2 negatively correlated with square root of exercise duration (within-subject r = -0.629, p < 0.001), the total post-exercise oxygen uptake till t(1/2) was thus constant irrespectively of exercise intensity. The method is simple and enables reliable comparisons of various modes of exercise with respect to the rate of recovery.

Maximal Oxygen Uptake, Sweating and Tolerance to Exercise in the Heat

NASA Technical Reports Server (NTRS)

Greenleaf, J. E.; Castle, B. L.; Ruff, W. K.

1972-01-01

The physiological mechanisms that facilitate acute acclimation to heat have not been fully elucidated, but the result is the establishment of a more efficient cardiovascular system to increase heat dissipation via increased sweating that allows the acclimated man to function with a cooler internal environment and to extend his performance. Men in good physical condition with high maximal oxygen uptakes generally acclimate to heat more rapidly and retain it longer than men in poorer condition. Also, upon first exposure trained men tolerate exercise in the heat better than untrained men. Both resting in heat and physical training in a cool environment confer only partial acclimation when first exposed to work in the heat. These observations suggest separate additive stimuli of metabolic heat from exercise and environmental heat to increase sweating during the acclimation process. However, the necessity of utilizing physical exercise during acclimation has been questioned. Bradbury et al. (1964) have concluded exercise has no effect on the course of heat acclimation since increased sweating can be induced by merely heating resting subjects. Preliminary evidence suggests there is a direct relationship between the maximal oxygen uptake and the capacity to maintain thermal regulation, particularly through the control of sweating. Since increased sweating is an important mechanism for the development of heat acclimation, and fit men have high sweat rates, it follows that upon initial exposure to exercise in the heat, men with high maximal oxygen uptakes should exhibit less strain than men with lower maximal oxygen uptakes. The purpose of this study was: (1) to determine if men with higher maximal oxygen uptakes exhibit greater tolerance than men with lower oxygen uptakes during early exposure to exercise in the heat, and (2) to investigate further the mechanism of the relationship between sweating and maximal work capacity.

Effects of prior warm-up regime on severe-intensity cycling performance.

PubMed

Burnley, Mark; Doust, Jonathan H; Jones, Andrew M

2005-05-01

The purpose of the present study was to determine the effect of three different warm-up regimes on cycling work output during a 7-min performance trial. After habituation to the experimental methods, 12 well-trained cyclists completed a series of 7-min performance trials, involving 2 min of constant-work rate exercise at approximately 90% VO2max and a further 5 min during which subjects attempted to maximize power output. This trial was performed without prior intervention and 10 min after bouts of moderate, heavy, or sprint exercise in a random order. Pulmonary gas exchange was measured breath by breath during all performance trials. At the onset of the performance trial, baseline blood [lactate] was significantly elevated after heavy and sprint but not moderate exercise (mean +/- SD: control, 1.0 +/- 0.3 mM; moderate, 1.0 +/- 0.2 mM; heavy, 3.0 +/- 1.1 mM; sprint, 5.9 +/- 1.5 mM). All three interventions significantly increased the amplitude of the primary VO2 response (control, 2.59 +/- 0.28 L x min(-1); moderate, 2.69 +/- 0.27 L x min(-1); heavy, 2.78 +/- 0.26 L x min(-1); sprint, 2.78 +/- 0.30 L x min(-1)). Mean power output was significantly increased by prior moderate and heavy exercise but not significantly reduced after sprint exercise (control, 330 +/- 42 W; moderate, 338 +/- 39 W; heavy, 339 +/- 42 W; sprint, 324 +/- 45 W). These data indicate that priming exercise performed in the moderate- and heavy-intensity domains can improve severe-intensity cycling performance by ~2-3%, the latter condition doing so despite a mild lactacidosis being present at exercise onset.

Influence of aerobic exercise intensity on myofibrillar and mitochondrial protein synthesis in young men during early and late postexercise recovery.

PubMed

Di Donato, Danielle M; West, Daniel W D; Churchward-Venne, Tyler A; Breen, Leigh; Baker, Steven K; Phillips, Stuart M

2014-05-01

Aerobic exercise is typically associated with expansion of the mitochondrial protein pool and improvements in muscle oxidative capacity. The impact of aerobic exercise intensity on the synthesis of specific skeletal muscle protein subfractions is not known. We aimed to study the effect of aerobic exercise intensity on rates of myofibrillar (MyoPS) and mitochondrial (MitoPS) protein synthesis over an early (0.5-4.5 h) and late (24-28 h) period during postexercise recovery. Using a within-subject crossover design, eight males (21 ± 1 yr, Vo2peak 46.7 ± 2.0 ml·kg(-1)·min(-1)) performed two work-matched cycle ergometry exercise trials (LOW: 60 min at 30% Wmax; HIGH: 30 min at 60% Wmax) in the fasted state while undergoing a primed constant infusion of l-[ring-(13)C6]phenylalanine. Muscle biopsies were obtained at rest and 0.5, 4.5, 24, and 28 h postexercise to determine both the "early" and "late" response of MyoPS and MitoPS and the phosphorylation status of selected proteins within both the Akt/mTOR and MAPK pathways. Over 24-28 h postexercise, MitoPS was significantly greater after the HIGH vs. LOW exercise trial (P < 0.05). Rates of MyoPS were increased equivalently over 0.5-4.5 h postexercise recovery (P < 0.05) but remained elevated at 24-28 h postexercise only following the HIGH trial. In conclusion, an acute bout of high- but not low-intensity aerobic exercise in the fasted state resulted in a sustained elevation of both MitoPS and MyoPS at 24-28 h postexercise recovery.

Reduced levels of skeletal muscle Na+K+ -ATPase in McArdle disease

NASA Technical Reports Server (NTRS)

Haller, R. G.; Clausen, T.; Vissing, J.; Blomqvist, C. G. (Principal Investigator)

1998-01-01

We evaluated the hypothesis that impaired sarcolemmal function associated with exaggerated potassium release, impaired potassium uptake, or both may contribute to exertional fatigue and abnormal circulatory responses to exercise in McArdle disease (MD). The cellular mechanism of exertional fatigue and muscle injury in MD is unknown but likely involves impaired function of the ATPases that couple ATP hydrolysis to cellular work, including the muscle sodium potassium pump (Na+K+-ATPase). However, the concentration of muscle Na+K+ pumps in MD is not known, and no studies have related exercise increases in blood potassium concentrations to muscle Na+K+ pump levels. We measured muscle Na+K+ pumps (3H-ouabain binding) and plasma K+ in response to 20 minutes of cycle exercise in six patients with MD and in six sex-, age-, and weight-matched sedentary individuals. MD patients had lower levels of 3H-ouabain binding (231 +/- 18 pmol/g w.w., mean +/- SD, range, 210 to 251) than control subjects (317 +/- 37, range, 266 to 371, p < 0.0004), higher peak increases in plasma potassium in response to 45 +/- 7 W cycle exercise (MD, 1.00 +/- 0.15 mmol/L; control subjects, 0.48 +/- 0.09; p < 0.0001), and mean exercise heart rate responses to exercise that were 45 +/- 12 bpm greater than control subjects. Our results indicate that Na+K+ pump levels are low in MD patients compared with healthy subjects and identify a limitation of potassium reuptake that could result in sarcolemmal failure during peak rates of membrane activation and may promote exaggerated potassium-activated circulatory responses to submaximal exercise. The mechanism of the low Na+K+ pump concentrations in MD is unknown but may relate to deconditioning or to disruption of a close functional relationship between membrane ion transport and glycolysis.

Influence of aerobic exercise intensity on myofibrillar and mitochondrial protein synthesis in young men during early and late postexercise recovery

PubMed Central

Di Donato, Danielle M.; West, Daniel W. D.; Churchward-Venne, Tyler A.; Breen, Leigh; Baker, Steven K.

2014-01-01

Aerobic exercise is typically associated with expansion of the mitochondrial protein pool and improvements in muscle oxidative capacity. The impact of aerobic exercise intensity on the synthesis of specific skeletal muscle protein subfractions is not known. We aimed to study the effect of aerobic exercise intensity on rates of myofibrillar (MyoPS) and mitochondrial (MitoPS) protein synthesis over an early (0.5–4.5 h) and late (24–28 h) period during postexercise recovery. Using a within-subject crossover design, eight males (21 ± 1 yr, V̇o2peak 46.7 ± 2.0 ml·kg−1·min−1) performed two work-matched cycle ergometry exercise trials (LOW: 60 min at 30% Wmax; HIGH: 30 min at 60% Wmax) in the fasted state while undergoing a primed constant infusion of l-[ring-13C6]phenylalanine. Muscle biopsies were obtained at rest and 0.5, 4.5, 24, and 28 h postexercise to determine both the “early” and “late” response of MyoPS and MitoPS and the phosphorylation status of selected proteins within both the Akt/mTOR and MAPK pathways. Over 24–28 h postexercise, MitoPS was significantly greater after the HIGH vs. LOW exercise trial (P < 0.05). Rates of MyoPS were increased equivalently over 0.5–4.5 h postexercise recovery (P < 0.05) but remained elevated at 24–28 h postexercise only following the HIGH trial. In conclusion, an acute bout of high- but not low-intensity aerobic exercise in the fasted state resulted in a sustained elevation of both MitoPS and MyoPS at 24–28 h postexercise recovery. PMID:24595306

Effects of aerobic exercise on the resting heart rate, physical fitness, and arterial stiffness of female patients with metabolic syndrome.

PubMed

Kang, Seol-Jung; Kim, Eon-Ho; Ko, Kwang-Jun

2016-06-01

[Purpose] The purpose of this study was to investigate the effects of aerobic exercise on the resting heart rate, physical fitness, and arterial stiffness or female patients with metabolic syndrome. [Subjects and Methods] Subjects were randomly assigned to an exercise group (n=12) or a control group (n=11). Subjects in the exercise group performed aerobic exercise at 60-80% of maximum heart rate for 40 min 5 times a week for 12 weeks. The changes in metabolic syndrome risk factors, resting heart rate, physical fitness, and arterial stiffness were measured and analyzed before and after initiation of the exercise program to determine the effect of exercise. Arterial stiffness was assessed based on brachial-ankle pulse wave velocity (ba-PWV). [Results] Compared to the control group; The metabolic syndrome risk factors (weight, % body fat, waist circumference, systolic blood pressure, diastolic blood pressure, and HDL-Cholesterol) were significantly improved in the exercise: resting heart rate was significantly decreased; VO2max, muscle strength and muscle endurance were significantly increased; and ba-PWV was significantly decreased. [Conclusion] Aerobic exercise had beneficial effects on the resting heart rate, physical fitness, and arterial stiffness of patients with metabolic syndrome.

Relationship between oxygen uptake slow component and surface EMG during heavy exercise in humans: influence of pedal rate.

PubMed

Vercruyssen, Fabrice; Missenard, Olivier; Brisswalter, Jeanick

2009-08-01

The aim of this study was to test the hypothesis that extreme pedal rates contributed to the slow component of oxygen uptake (VO(2) SC) in association with changes in surface electromyographic (sEMG) during heavy-cycle exercise. Eight male trained cyclists performed two square-wave transitions at 50 and 110 rpm at a work rate that would elicit a VO(2) corresponding to 50% of the difference between peak VO(2) and the ventilatory threshold. Pulmonary gas exchange was measured breath-by-breath and sEMG was obtained from the vastus lateralis and medialis muscles. Integrated EMG flow (QiEMG) and mean power frequency (MPF) were computed. The relative amplitude of the VO(2) SC was significantly higher during the 110-rpm bout (556+/-186 ml min(-1), P<0.05) with compared to the 50-rpm bout (372+/-227 ml min(-1)). QiEMG values increased throughout exercise only during the 110-rpm bout and were associated with the greater amplitude of the VO(2) SC observed for this condition (P<0.05). MPF values remained relatively constant whatever the cycle bout. These findings indicated a VO(2) SC at the two pedal rates but the association with sEMG responses was observed only at high pedal rate. Possible changes in motor units recruitment pattern, muscle energy turnover and muscle temperature have been suggested to explain the different VO(2) SC to heavy pedal rate bouts.

Effectiveness of ice-vest cooling in prolonging work tolerance time during heavy exercise in the heat for personnel wearing Canadian forces chemical defense ensembles

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

Bain, B.

Effectiveness of a portable, ice-pack cooling vest (Steelevest) in prolonging work tolerance time in chemical defense clothing in the heat (33 C dry bulb, 33% relative humidity or 25 C WBGT) was evaluated while subjects exercised at a metabolic rate of approx. 700 watts. Subjects were six male volunteers. The protocol consisted of a 20 minute treadmill walk at 1.33 m/s. and 7.5% grade, followed by 15 minutes of a lifting task, 5 minutes rest, then another 20 minutes of lifting task for a total of one hour. The lifting task consisted of lifting of 20 kg box, carrying itmore » 3 meters and setting it down. This was followed by a 6 m walk (3m back to the start point and 3 m back to the box) 15 sec after which the lifting cycle began again. The work was classified as heavy as previously defined. This protocol was repeated until the subjects were unable to continue or they reached a physiological endpoint. Time to voluntary cessation or physiological endpoint was called the work tolerance time. Physiological endpoints were rectal temperature of 39 C, heart rate exceeding 95% of maximum for two consecutive minutes or visible loss of motor control or nausea. The cooling vest had no effect on work tolerance time, rate of rise of rectal temperature or sweat loss. It was concluded that the Steelvest ice-vest is ineffective in prolonging work tolerance time and preventing increases in rectal temperature while wearing chemical protective clothing.« less

Progressive Resistance and Balance Training for Falls Prevention in Long-Term Residential Aged Care: A Cluster Randomized Trial of the Sunbeam Program.

PubMed

Hewitt, Jennifer; Goodall, Stephen; Clemson, Lindy; Henwood, Timothy; Refshauge, Kathryn

2018-04-01

Falls prevention is an international priority, and residents of long-term aged care fall approximately 3 times more often than community dwellers. There is a relative scarcity of published trials in this setting. Our objective was to undertake a randomized controlled trial to test the effect of published best practice exercise in long-term residential aged care. The trial was designed to determine if combined high level balance and moderate intensity progressive resistance training (the Sunbeam Program) is effective in reducing the rate of falls in residents of aged care facilities. A cluster randomized controlled trial of 16 residential aged care facilities and 221 participants was conducted. The broad inclusion criterion was permanent residents of aged care. Exclusions were diagnosed terminal illness, no medical clearance, permanent bed- or wheelchair-bound status, advanced Parkinson's disease, or insufficient cognition to participate in group exercise. Assessments were taken at baseline, after intervention, and at 12 months. Randomization was performed by computer-generated sequence to receive either the Sunbeam program or usual care. A cluster refers to an aged care facility. The program consisted of individually prescribed progressive resistance training plus balance exercise performed in a group setting for 50 hours over a 25-week period, followed by a maintenance period for 6 months. The primary outcome measure was the rate of falls (number of falls and days followed up). Secondary outcomes included physical performance (Short Physical Performance Battery), quality of life (36-item Short-Form Health Survey), functional mobility (University of Alabama Life Space Assessment), fear of falling (Falls Efficacy Scale International), and cognition (Addenbrooke's Cognitive Evaluation-revised). The rate of falls was reduced by 55% in the exercise group (incidence rate ratio = 0.45, 95% confidence interval 0.17-0.74); an improvement was also seen in physical performance (P = .02). There were no serious adverse events. The Sunbeam Program significantly reduced the rate of falls and improved physical performance in residents of aged care. This finding is important as prior work in this setting has returned inconsistent outcomes, resulting in best practice guidelines being cautious about recommending exercise in this setting. This work provides an opportunity to improve clinical practice and health outcomes for long-term care residents. Copyright © 2017 AMDA – The Society for Post-Acute and Long-Term Care Medicine. Published by Elsevier Inc. All rights reserved.

Environmental and policy factors related to physical activity in rural white women.

PubMed

Eyler, Amy A; Vest, Joshua R

2002-01-01

Physical activity is an important aspect of health promotion and disease prevention. However, women often have lower rates of physical activity than men. The purpose of this study was to identify environmental and policy determinants to physical activity among rural white women. Six focus groups were conducted with women aged 20-50 years who were not currently regular exercisers. Women reported that the social environment had a strong impact on physical activity level. Factors of the social environment included guilt, family responsibility, and social support. Environmental and policy barriers such as lack of access to places to exercise and safety concerns were also discussed. Intervention suggestions included family exercise and work-site programs. Information gained from this study can be used to fuel further research and inform future physical activity interventions.

The association between different types of exercise and energy expenditure in young nonoverweight and overweight adults

PubMed Central

Drenowatz, Clemens; Hand, Gregory A.; Shook, Robin P.; Jakicic, John M.; Hebert, James R.; Burgess, Stephanie; Blair, Steven N.

2015-01-01

With decades of trends for decreasing activity during work and travel, exercise becomes an important contributor to total physical activity (PA) and energy expenditure. The purpose of this study was to examine the contribution of different types of exercise to the variability in energy expenditure and time spent at different PA intensities in young adults. Four hundred and seventeen adults (49.9% male; 46.2 overweight/obese) between 21 and 36 years of age provided valid objective PA and energy expenditure data, assessed via the SenseWear Armband (BodyMedia Inc.). Frequency and duration of participation in various exercise types was self-reported. Weight status was based on body mass index (BMI) (kg/m2) with body weight and height being measured according to standard procedures. Eighty-four percent of the participants reported regular exercise engagement with no difference in participation rate by sex or BMI category. Exercise time along with sex and ethnicity explained roughly 60% of the variability in total daily energy expenditure (TDEE) while the association between exercise and time spent in moderate to vigorous PA or being sedentary was low or nonsignificant. Engagement in endurance exercise and sports contributed predominantly to the variability in energy expenditure and PA in nonoverweight participants. In overweight/obese participants engagement in resistance exercise and swimming contributed significantly to variability in TDEE. Current exercise recommendations focus primarily on aerobic exercise, but results of the present study suggest that nonweight-bearing exercises, such as resistance exercise and swimming, contribute significantly to the variability in TDEE in overweight/obese adults, which would make these types of activities viable options for exercise interventions. PMID:25647557

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.

Fatigue Analysis Before and After Shaker Exercise: Physiologic Tool for Exercise Design

PubMed Central

White, Kevin T.; Easterling, Caryn; Roberts, Niles; Shaker, Reza

2016-01-01

Recent studies suggest that the Shaker exercise induces fatigue in the upper esophageal sphincter (UES) opening muscles and sternocleidomastoid (SCM), with the SCMs fatiguing earliest. The aim of this study was to measure fatigue induced by the isometric portion of the Shaker exercise by measuring the rate of change in the median frequency (MF rate) of the power spectral density (PSD) function, which is interpreted as proportional to the rate of fatigue, from surface electromyography (EMG) of suprahyoid (SHM), infrahyoid (IHM), and SCM. EMG data compared fatigue-related changes from 20-, 40-, and 60-s isometric hold durations of the Shaker exercise. We found that fatigue-related changes were manifested during the 20-s hold. The findings confirm that the SCM fatigues initially and as fast as or faster than the SHM and IHM. In addition, upon completion of the exercise protocol, the SCM had a decreased MF rate, implying improved fatigue resistance, while the SHM and IHM showed increased MF rates, implying that these muscles increased their fatiguing effort. We conclude that the Shaker exercise initially leads to increased fatigue resistance of the SCM, after which the exercise loads the less fatigue-resistant SHM and IHM, potentiating the therapeutic effect of the Shaker exercise regimen with continued exercise performance. PMID:18369673

Psychophysiological effects of audiovisual stimuli during cycle exercise.

PubMed

Barreto-Silva, Vinícius; Bigliassi, Marcelo; Chierotti, Priscila; Altimari, Leandro R

2018-05-01

Immersive environments induced by audiovisual stimuli are hypothesised to facilitate the control of movements and ameliorate fatigue-related symptoms during exercise. The objective of the present study was to investigate the effects of pleasant and unpleasant audiovisual stimuli on perceptual and psychophysiological responses during moderate-intensity exercises performed on an electromagnetically braked cycle ergometer. Twenty young adults were administered three experimental conditions in a randomised and counterbalanced order: unpleasant stimulus (US; e.g. images depicting laboured breathing); pleasant stimulus (PS; e.g. images depicting pleasant emotions); and neutral stimulus (NS; e.g. neutral facial expressions). The exercise had 10 min of duration (2 min of warm-up + 6 min of exercise + 2 min of warm-down). During all conditions, the rate of perceived exertion and heart rate variability were monitored to further understanding of the moderating influence of audiovisual stimuli on perceptual and psychophysiological responses, respectively. The results of the present study indicate that PS ameliorated fatigue-related symptoms and reduced the physiological stress imposed by the exercise bout. Conversely, US increased the global activity of the autonomic nervous system and increased exertional responses to a greater degree when compared to PS. Accordingly, audiovisual stimuli appear to induce a psychophysiological response in which individuals visualise themselves within the story presented in the video. In such instances, individuals appear to copy the behaviour observed in the videos as if the situation was real. This mirroring mechanism has the potential to up-/down-regulate the cardiac work as if in fact the exercise intensities were different in each condition.

Influence of Exercise on Patients with Guillain-Barré Syndrome: A Systematic Review

PubMed Central

Vincent, Pierre-Olivier; Yu, Bai He Shen; Bastien, Robin; Sweeney, Aaron

2016-01-01

Purpose: To evaluate the effects of exercise interventions on improving physical outcomes in patients with Guillain-Barré syndrome (GBS). Methods: The PubMed database was searched for articles published up to and including February 2015. Randomized controlled trials (RCTs), case reports, and quasi-experimental and single-subject designs published in English-language, peer-reviewed journals that assessed the impact of physical exercise on patients with GBS were included; study quality was assessed using Sackett's rules of evidence. Data are presented qualitatively and quantitatively using numerical values and percentages. Results: Seven articles were included in the systematic review. One RCT showed that high-intensity relative to lower intensity exercise significantly reduced disability in patients with GBS, as measured with the FIM (p<0.005, r=0.71). Overall, various types of exercise programmes improve physical outcomes such as functional mobility, cardiopulmonary function, isokinetic muscle strength, and work rate and reduce fatigue in patients with GBS. Conclusion: Because of insufficient high-quality literature, making confident conclusions about the effects of exercise interventions on physical outcomes in patients with GBS is not possible. Future research should consider using higher quality study designs to confirm the results outlined in this article. PMID:27904236

Can supine recovery mitigate the exercise intensity dependent attenuation of post-exercise heat loss responses?

PubMed

Kenny, Glen P; Gagnon, Daniel; Jay, Ollie; McInnis, Natalie H; Journeay, W Shane; Reardon, Francis D

2008-08-01

Cutaneous vascular conductance (CVC) and sweat rate are subject to non-thermal baroreflex-mediated attenuation post-exercise. Various recovery modalities have been effective in attenuating these decreases in CVC and sweat rate post-exercise. However, the interaction of recovery posture and preceding exercise intensity on post-exercise thermoregulation remains unresolved. We evaluated the combined effect of supine recovery and exercise intensity on post-exercise cardiovascular and thermal responses relative to an upright seated posture. Seven females performed 15 min of cycling ergometry at low- (LIE, 55% maximal oxygen consumption) or high-(HIE, 85% maximal oxygen consumption) intensity followed by 60 min of recovery in either an upright seated or supine posture. Esophageal temperature, CVC, sweat rate, cardiac output, stroke volume, heart rate, total peripheral resistance, and mean arterial pressure (MAP) were measured at baseline, at end-exercise, and at 2, 5, 12, 20, and every 10 min thereafter until the end of recovery. MAP and stroke volume were maintained during supine recovery to a greater extent relative to an upright seated recovery following HIE (p

Post-exercise heart rate recovery in healthy, obeses, and COPD subjects: relationships with blood lactic acid and PaO2 levels.

PubMed

Ba, Abdoulaye; Delliaux, Stephane; Bregeon, Fabienne; Levy, Samuel; Jammes, Yves

2009-01-01

Because blood acidosis and arterial oxygenation (PaO(2)) play key roles in the chemoreflex control of cardiac activity, we hypothesized that heart rate (HR) decay rate after maximal exercise may be linked to post-exercise increase in blood lactate (LA) level and/or the resting PaO(2). Twenty healthy subjects and thirty five patients at risks of cardiovascular diseases (20 obeses; 15 patients with chronic obstructive pulmonary disease, COPD) performed a maximal cycling exercise. During the recovery period, HR was continuously measured for consecutive 10-s epochs allowing to compute linear or second order polynomial equations and to calculate every minute HR variations compared to peak HR value (DeltaHR). PaO(2) was measured at rest and post-exercise maximal LA level was determined. A second order polynomial equation (y = a(2) x (2) + b(2) x + c) best fitted the post-exercise HR decay rate. The a(2) and b(2) coefficients and DeltaHR did not depend on age, sex, and body mass index. Despite a large scattering of HR decay rate, even present in healthy subjects, a(2) and DeltaHR were significantly lower in obeses and COPDs. In the whole population, both a(2) coefficient and DeltaHR were negatively correlated with maximal post-exercise LA level. DeltaHR was lowered in hypoxemic patients. Thus, the slowest post-exercise HR decay rate was measured in subjects having the highest peak LA increase or hypoxemia. Thus, even in healthy subjects, the post-exercise HR decay rate is lowered in individuals having an accentuated exercise-induced LA increase and/or hypoxemia. The mechanisms of delayed post-exercise HR recovery are only suspected because significant correlations cannot assess cause-to-effect relationships.

Perceived correlates of domain-specific physical activity in rural adults in the Midwest.

PubMed

Chrisman, Matthew; Nothwehr, Faryle; Yang, Jingzen; Oleson, Jacob

2014-01-01

In response to calls for more specificity when measuring physical activity, this study examined perceived correlates of this behavior in rural adults separately by the domain in which this behavior occurs (ie, home care, work, active living, and sport). A cross-sectional survey was completed by 407 adults from 2 rural towns in the Midwest. The questionnaire assessed the perceived social and physical environment, including neighborhood characteristics, as well as barriers to being active. The Kaiser Physical Activity Survey captured domain-specific activity levels. The response rate was 25%. Multiple regression analyses were conducted to examine the associations between social and physical environment factors and domain-specific physical activity. Having a favorable attitude toward using government funds for exercise and activity-friendly neighborhood characteristic were positively associated with active living. Friends encouraging exercise was positively associated with participation in sport. Barriers were inversely associated with active living and sport. Total physical activity was positively associated with workplace incentives for exercise, favorable policy attitudes toward supporting physical education in schools and supporting the use of government funds for biking trails, and it was inversely associated with barriers. There were no factors associated with physical activity in the domains of work or home care. Correlates of physical activity are unique to the domain in which this behavior occurs. Programs to increase physical activity in rural adults should target policy attitudes, neighborhood characteristics, and social support from friends while also working to decrease personal barriers to exercise. © 2014 National Rural Health Association.

Perceived Correlates of Domain-Specific Physical Activity in Rural Adults in the Midwest

PubMed Central

Chrisman, Matthew; Nothwehr, Faryle; Yang, Jingzen; Oleson, Jacob

2014-01-01

Purpose In response to calls for more specificity when measuring physical activity, this study examined perceived correlates of this behavior in rural adults separately by the domain in which this behavior occurs (ie, home care, work, active living, and sport). Methods A cross-sectional survey was completed by 407 adults from 2 rural towns in the Midwest. The questionnaire assessed the perceived social and physical environment, including neighborhood characteristics, as well as barriers to being active. The Kaiser Physical Activity Survey captured domainspecific activity levels. The response rate was 25%. Multiple regression analyses were conducted to examine the associations between social and physical environment factors and domain-specific physical activity. Findings Having a favorable attitude toward using government funds for exercise and activity-friendly neighborhood characteristic were positively associated with active living. Friends encouraging exercise was positively associated with participation in sport. Barriers were inversely associated with active living and sport. Total physical activity was positively associated with workplace incentives for exercise, favorable policy attitudes toward supporting physical education in schools and supporting the use of government funds for biking trails, and it was inversely associated with barriers. There were no factors associated with physical activity in the domains of work or home care. Conclusions Correlates of physical activity are unique to the domain in which this behavior occurs. Programs to increase physical activity in rural adults should target policy attitudes, neighborhood characteristics, and social support from friends while also working to decrease personal barriers to exercise. PMID:24576053

Cardiorespiratory response to exercise testing in individuals with Alzheimer’s disease

PubMed Central

Billinger, Sandra A.; Vidoni, Eric D.; Honea, Robyn A.; Burns, Jeffrey M.

2011-01-01

Objective To exercise testing in AD and possible disease-related change over time. Though physical activity and fitness are receiving increased attention as a possible adjunct treatment for Alzheimer’s disease (AD), relatively little work has been done characterizing their physiologic response to exercise Design Retrospective assessment of a 2-year, observational study Setting University medical center Participants 50 nondemented individuals and 31 with AD Interventions None Main Outcome Measures Participants underwent a clinical dementia evaluation and performed an incremental exercise test using a treadmill and the modified Bruce protocol at baseline and at a two year follow-up. We examined oxygen consumption, minute ventilation, heart rate and ventilatory equivalents for oxygen and carbon dioxide at submaximal and peak exercise intensities to determine if the measures were different between groups or over time. Results AD and nondemented participants performed similarly at submaximal effort and both groups showed similar change in exercise response over 2 years. However, nondemented individuals had consistently higher values of oxygen consumption (p≤0.02) and minute ventilation at peak effort at baseline (p=0.003). Conclusions Individuals with AD demonstrate physiologic responses to submaximal exercise effort that are not significantly different than individuals without dementia. However, differences are apparent at the extreme of effort. PMID:22133248

[Evaluation of benefits of the course of positive pressure breathing training on exercise performance].

PubMed

Medvedev, D V; Gorbaneva, E P; Iumatova, S N; Kuznetsova, T Iu; Solopov, I N; Katuntsev, V P

2007-01-01

The purpose was to evaluate effects of muscle training combined with positive pressure breathing on exercise performance of 16 runners at the age of 18-20. All subjects had the first or second-class sport qualification. The 4-wk. training course for the experimental group (n=11) included 20-25% of exercises performed in an aperture mask creating an inspiration-expiration resistance of 8-10 mm H2O. The control group (n=5) worked on the same training course but w/o positive pressure breathing. The course began and ended with the PWC170 test in order to evaluate exercise performance. Indices of external respiration and gas exchange were determined on metabolograph Ergooxyscreen (Jaeger) and lung-tester Spirosift-3000 (Fukuda). Inspiration and expiration force of the breathing muscles (mm Hg) was measured isometrically with the help of a pneumomanometer. Heart rate was calculated from ECG R-R intervals. It was stated that positive pressure breathing during muscle training increases significantly sportsmen's exercise performance due to growth of the body spare capacities, and optimization of the body systems dependence structure and efficiency.

The Effects of Heat Adaptation on Physiology, Perception and Exercise Performance in the Heat: A Meta-Analysis.

PubMed

Tyler, Christopher J; Reeve, Tom; Hodges, Gary J; Cheung, Stephen S

2016-11-01

Exercise performance and capacity are impaired in hot, compared to temperate, conditions. Heat adaptation (HA) is one intervention commonly adopted to reduce this impairment because it may induce beneficial exercise performance and physiological and perceptual adaptations. A number of investigations have been conducted on HA but, due to large methodological differences, the effectiveness of different HA regimens remain unclear. (1) To quantify the effect of different HA regimens on exercise performance and the physiological and perceptual responses to subsequent heat exposure. (2) To offer practical HA recommendations and suggestions for future HA research based upon a systematic and quantitative synthesis of the literature. PubMed was searched for original research articles published up to, and including, 16 February 2016 using appropriate first- and second-order search terms. English-language, peer-reviewed, full-text original articles using human participants were reviewed using the four-stage process identified in the PRISMA statement. Data for the following variables were obtained from the manuscripts by at least two of the authors: participant sex, maximal oxygen consumption and age; HA duration, frequency, modality, temperature and humidity; exercise performance and capacity; core and skin temperature; heart rate, stroke volume, cardiac output, skin blood flow, sweat onset temperature, body mass loss, sweat rate, perception of thirst, volitional fluid consumption, plasma volume changes; sweat concentrations of sodium, chloride and potassium; aldosterone, arginine vasopressin, heat shock proteins (Hsp), ratings of perceived exertion (RPE) and thermal sensation. Data were divided into three groups based upon the frequency of the HA regimen. Performance and capacity data were also divided into groups based upon the type of HA used. Hedges' g effect sizes and 95 % confidence intervals were calculated. Correlations were run where appropriate. Ninety-six articles were reviewed. The most common duration was 7-14 days and the most common method of HA was the controlled work-rate approach. HA had a moderately beneficial effect on exercise capacity and performance in the heat irrespective of regimen; however, longer regimens were more effective than shorter approaches. HA had a moderate-to-large beneficial effect on lowering core body temperature before and during exercise, maintaining cardiovascular stability, and improving heat-loss pathways. Data are limited but HA may reduce oxygen consumption during subsequent exercise, improve glycogen sparing, increase the power output at lactate threshold, reduce lactate concentrations during exercise, have a trivial effect on increasing extracellular concentrations of Hsp, and improve perceived ratings of exertion and thermal sensation. HA regimens lasting <14 days induce many beneficial physiological and perceptual adaptations to high ambient temperatures, and improve subsequent exercise performance and capacity in the heat; however, the extent of the adaptations is greatest when HA regimens lasting longer than 14 days are adopted. Large methodological differences in the HA literature mean that there is still uncertainty regarding the magnitude and time course of potential adaptation for a number of physiological and perceptual variables.

Heart rate recovery after maximal exercise is blunted in hypertensive seniors.

PubMed

Best, Stuart A; Bivens, Tiffany B; Dean Palmer, M; Boyd, Kara N; Melyn Galbreath, M; Okada, Yoshiyuki; Carrick-Ranson, Graeme; Fujimoto, Naoki; Shibata, Shigeki; Hastings, Jeffrey L; Spencer, Matthew D; Tarumi, Takashi; Levine, Benjamin D; Fu, Qi

2014-12-01

Abnormal heart rate recovery (HRR) after maximal exercise may indicate autonomic dysfunction and is a predictor for cardiovascular mortality. HRR is attenuated with aging and in middle-age hypertensive patients, but it is unknown whether HRR is attenuated in older-age adults with hypertension. This study compared HRR among 16 unmedicated stage 1 hypertensive (HTN) participants [nine men/seven women; 68 ± 5 (SD) yr; awake ambulatory blood pressure (BP) 149 ± 10/87 ± 7 mmHg] and 16 normotensive [control (CON)] participants (nine men/seven women; 67 ± 5 yr; 122 ± 4/72 ± 5 mmHg). HR, BP, oxygen uptake (V̇o2), cardiac output (Qc), and stroke volume (SV) were measured at rest, at two steady-state work rates, and graded exercise to peak during maximal treadmill exercise. During 6 min of seated recovery, the change in HR (ΔHR) was obtained every minute and BP every 2 min. In addition, HRR and R-R interval (RRI) recovery kinetics were analyzed using a monoexponential function, and the indexes (HRRI and RRII) were calculated. Maximum V̇o2, HR, Qc, and SV responses during exercise were not different between groups. ΔHR was significantly different (P < 0.001) between the HTN group (26 ± 8) and the CON group (36 ± 12 beats/min) after 1 min of recovery but less convincing at 2 min (P = 0.055). BP recovery was similar between groups. HRRI was significantly lower (P = 0.016), and there was a trend of lower RRII (P = 0.066) in the HTN group compared with the CON group. These results show that in older-age adults, HRR is attenuated further with the presence of hypertension, which may be attributable to an impairment of autonomic function. Copyright © 2014 the American Physiological Society.

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

PubMed

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

2017-07-19

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

Heart rate recovery after maximal exercise is blunted in hypertensive seniors

PubMed Central

Best, Stuart A.; Bivens, Tiffany B.; Dean Palmer, M.; Boyd, Kara N.; Melyn Galbreath, M.; Okada, Yoshiyuki; Carrick-Ranson, Graeme; Shibata, Shigeki; Hastings, Jeffrey L.; Spencer, Matthew D.; Tarumi, Takashi; Levine, Benjamin D.; Fu, Qi

2014-01-01

Abnormal heart rate recovery (HRR) after maximal exercise may indicate autonomic dysfunction and is a predictor for cardiovascular mortality. HRR is attenuated with aging and in middle-age hypertensive patients, but it is unknown whether HRR is attenuated in older-age adults with hypertension. This study compared HRR among 16 unmedicated stage 1 hypertensive (HTN) participants [nine men/seven women; 68 ± 5 (SD) yr; awake ambulatory blood pressure (BP) 149 ± 10/87 ± 7 mmHg] and 16 normotensive [control (CON)] participants (nine men/seven women; 67 ± 5 yr; 122 ± 4/72 ± 5 mmHg). HR, BP, oxygen uptake (V̇o2), cardiac output (Qc), and stroke volume (SV) were measured at rest, at two steady-state work rates, and graded exercise to peak during maximal treadmill exercise. During 6 min of seated recovery, the change in HR (ΔHR) was obtained every minute and BP every 2 min. In addition, HRR and R-R interval (RRI) recovery kinetics were analyzed using a monoexponential function, and the indexes (HRRI and RRII) were calculated. Maximum V̇o2, HR, Qc, and SV responses during exercise were not different between groups. ΔHR was significantly different (P < 0.001) between the HTN group (26 ± 8) and the CON group (36 ± 12 beats/min) after 1 min of recovery but less convincing at 2 min (P = 0.055). BP recovery was similar between groups. HRRI was significantly lower (P = 0.016), and there was a trend of lower RRII (P = 0.066) in the HTN group compared with the CON group. These results show that in older-age adults, HRR is attenuated further with the presence of hypertension, which may be attributable to an impairment of autonomic function. PMID:25301897

The effects of recovery duration during high-intensity interval exercise on time spent at high rates of oxygen consumption, oxygen kinetics and blood lactate.

PubMed

Smilios, Ilias; Myrkos, Aristides; Zafeiridis, Andreas; Toubekis, Argyris; Spassis, Apostolos; Tokmakidis, Savas P

2017-03-13

The recovery duration and the work to recovery ratio are important aspects to consider when designing a high-intensity aerobic interval exercise (HIIE). This study examined the effects of recovery duration on total exercise time performed above 80, 90 and 95% of maximum oxygen consumption (VO2max) and heart rate (HRmax) during a single-bout HIIE. We also evaluated the effects on VO2 and HR kinetics, blood lactate concentration and rating of perceived exertion (RPE). Eleven moderately trained males (22.1±1 yrs.) executed, on three separate sessions, 4×4-min runs at 90% of maximal aerobic velocity (MAV) with 2-min, 3-min and 4-min of active recovery. Recovery duration did not affect the percentage of VO2max attained and the total exercise time above 80, 90 and 95% of VO2max. Exercise time above 80 and 90% of HRmax was longer with 2 and 3 min (p<0.05) as compared with the 4-min recovery. Oxygen uptake and HR amplitude were lower, mean response time slower (p<0.05), and blood lactate and RPE higher with 2-min compared to 4-min recovery (p<0.05). In conclusion, aerobic metabolism attains its upper functional limits with either 2, or 3 or 4 min of recovery during the 4×4 min HIIE; thus, all rest durations could be used for the enhancement of aerobic capacity in sports, fitness, and clinical settings. The short (2 min) compared to longer (4 min) recovery, however, evokes greater cardiovascular and metabolic stress, and activates to a greater extent anaerobic glycolysis, and hence, could be used by athletes to induce greater overall physiological challenge.

Reduced Tic Symptomatology in Tourette Syndrome After an Acute Bout of Exercise: An Observational Study.

PubMed

Nixon, Elena; Glazebrook, Cris; Hollis, Chris; Jackson, Georgina M

2014-03-01

In light of descriptive accounts of attenuating effects of physical activity on tics, we used an experimental design to assess the impact of an acute bout of aerobic exercise on tic expression in young people (N = 18) with Tourette Syndrome (TS). We compared video-based tic frequency estimates obtained during an exercise session with tic rates obtained during pre-exercise (baseline) and post-exercise interview-based sessions. Results showed significantly reduced tic rates during the exercise session compared with baseline, suggesting that acute exercise has an attenuating effect on tics. Tic rates also remained reduced relative to baseline during the post-exercise session, likely reflecting a sustained effect of exercise on tic reduction. Parallel to the observed tic attenuation, exercise also had a beneficial impact on self-reported anxiety and mood levels. The present findings provide novel empirical evidence for the beneficial effect of exercise on TS symptomatology bearing important research and clinical implications. © The Author(s) 2014.

Cardiorespiratory demand of acute voluntary cycling with functional electrical stimulation in individuals with multiple sclerosis with severe mobility impairment.

PubMed

Edwards, Thomas; Motl, Robert W; Pilutti, Lara A

2018-01-01

Exercise training is one strategy for improving cardiorespiratory fitness (CRF) in multiple sclerosis (MS); however, few modalities are accessible for those with severe mobility impairment. Functional electrical stimulation (FES) cycling is an adapted exercise modality with the potential for improving CRF in people with severe MS. The objective of this study was to characterize the cardiorespiratory response of acute voluntary cycling with FES in people with MS with severe mobility impairment, and to compare this response to passive leg cycling. Eleven participants with MS that required assistance for ambulation completed a single bout of voluntary cycling with FES or passive leg cycling. Oxygen consumption, heart rate (HR), work rate (WR), and ratings of perceived exertion (RPE) were recorded throughout the session. For the FES group, mean exercising oxygen consumption was 8.7 ± 1.8 mL/(kg·min) -1 , or 63.5% of peak oxygen consumption. Mean HR was 102 ± 9.7 bpm, approximately 76.4% of peak HR. Mean WR was 27.0 ± 9.2 W, or 57.3% of peak WR, and median RPE was 13.5 (interquartile range = 5.5). Active cycling with FES was significantly (p < 0.05) more intense than passive leg cycling based on oxygen consumption, HR, WR, and RPE during exercise. In conclusion, voluntary cycling with FES elicited an acute response that corresponded with moderate-to vigorous-intensity activity, suggesting that active cycling with FES can elicit a sufficient stimulus for improving CRF.

Characterization of Cardiopulmonary Exercise Testing Variables in Patients with Endomyocardial Fibrosis after Endocardial Resection

PubMed Central

Sayegh, Ana Luiza C.; dos Santos, Marcelo R.; de Oliveira, Patricia; Fernandes, Fábio; Rondon, Eduardo; de Souza, Francis R.; Salemi, Vera M. C.; Alves, Maria Janieire de N. N.; Mady, Charles

2017-01-01

Background Endomyocardial fibrosis (EMF) is a rare disease, characterized by diastolic dysfunction which leads to reduced peak oxygen consumption (VO2). Cardiopulmonary exercise testing (CPET) has been proved to be a fundamental tool to identify central and peripheral alterations. However, most studies prioritize peak VO2 as the main variable, leaving aside other important CPET variables that can specify the severity of the disease and guide the clinical treatment. Objective The aim of this study was to evaluate central and peripheral limitations in symptomatic patients with EMF by different CPET variables. Methods Twenty-six EMF patients (functional class III, NYHA) were compared with 15 healthy subjects (HS). Functional capacity was evaluated using CPET and diastolic and systolic functions were evaluated by echocardiography. Results Age and gender were similar between EMF patients and HS. Left ventricular ejection fraction was normal in EMF patients, but decreased compared to HS. Peak heart rate, peak workload, peak VO2, peak oxygen (O2) pulse and peak pulmonary ventilation (VE) were decreased in EMF compared to HS. Also, EMF patients showed increased Δ heart rate /Δ oxygen uptake and Δ oxygen uptake /Δ work rate compared to HS. Conclusion Determination of the aerobic capacity by noninvasive respiratory gas exchange during incremental exercise provides additional information about the exercise tolerance in patients with EMF. The analysis of different CPET variables is necessary to help us understand more about the central and peripheral alterations cause by both diastolic dysfunction and restrictive pattern. PMID:29364349

TROIKA: a general framework for heart rate monitoring using wrist-type photoplethysmographic signals during intensive physical exercise.

PubMed

Zhang, Zhilin; Pi, Zhouyue; Liu, Benyuan

2015-02-01

Heart rate monitoring using wrist-type photoplethysmographic signals during subjects' intensive exercise is a difficult problem, since the signals are contaminated by extremely strong motion artifacts caused by subjects' hand movements. So far few works have studied this problem. In this study, a general framework, termed TROIKA, is proposed, which consists of signal decomposiTion for denoising, sparse signal RecOnstructIon for high-resolution spectrum estimation, and spectral peaK trAcking with verification. The TROIKA framework has high estimation accuracy and is robust to strong motion artifacts. Many variants can be straightforwardly derived from this framework. Experimental results on datasets recorded from 12 subjects during fast running at the peak speed of 15 km/h showed that the average absolute error of heart rate estimation was 2.34 beat per minute, and the Pearson correlation between the estimates and the ground truth of heart rate was 0.992. This framework is of great values to wearable devices such as smartwatches which use PPG signals to monitor heart rate for fitness.

Let me take the wheel: Illusory control and sense of agency

PubMed Central

Tobias-Webb, Juliette; Limbrick-Oldfield, Eve H.; Gillan, Claire M.; Moore, James W.; Aitken, Michael R. F.; Clark, Luke

2017-01-01

ABSTRACT Illusory control refers to an effect in games of chance where features associated with skilful situations increase expectancies of success. Past work has operationalized illusory control in terms of subjective ratings or behaviour, with limited consideration of the relationship between these definitions, or the broader construct of agency. This study used a novel card-guessing task in 78 participants to investigate the relationship between subjective and behavioural illusory control. We compared trials in which participants (a) had no opportunity to exercise illusory control, (b) could exercise illusory control for free, or (c) could pay to exercise illusory control. Contingency Judgment and Intentional Binding tasks assessed explicit and implicit sense of agency, respectively. On the card-guessing task, confidence was higher when participants exerted control than in the baseline condition. In a complementary model, participants were more likely to exercise control when their confidence was high, and this effect was accentuated in the pay condition relative to the free condition. Decisions to pay were positively correlated with control ratings on the Contingency Judgment task, but were not significantly related to Intentional Binding. These results establish an association between subjective and behavioural illusory control and locate the construct within the cognitive literature on agency. PMID:27376771

Back to the future! Revisiting the physiological cost of negative work as a team-based activity for exercise physiology students.

PubMed

Kilgas, Matthew A; Elmer, Steven J

2017-03-01

We implemented a team-based activity in our exercise physiology teaching laboratory that was inspired from Abbott et al.'s classic 1952 Journal of Physiology paper titled "The physiological cost of negative work." Abbott et al. connected two bicycles via one chain. One person cycled forward (muscle shortening contractions, positive work) while the other resisted the reverse moving pedals (muscle lengthening contractions, negative work), and the cost of work was compared. This study was the first to link human whole body energetics with isolated muscle force-velocity characteristics. The laboratory activity for our students ( n = 35) was designed to reenact Abbott et al.'s experiment, integrate previously learned techniques, and illustrate differences in physiological responses to muscle shortening and lengthening contractions. Students (11-12 students/laboratory section) were split into two teams (positive work vs. negative work). One student from each team volunteered to cycle against the other for ~10 min. The remaining students in each team were tasked with measuring: 1 ) O 2 consumption, 2 ) heart rate, 3 ) blood lactate, and 4 ) perceived exertion. Students discovered that O 2 consumption during negative work was about one-half that of positive work and all other physiological parameters were also substantially lower. Muscle lengthening contractions were discussed and applied to rehabilitation and sport training. The majority of students (>90%) agreed or strongly agreed that they stayed engaged during the activity and it improved their understanding of exercise physiology. All students recommended the activity be performed again. This activity was engaging, emphasized teamwork, yielded clear results, was well received, and preserved the history of classic physiological experiments. Copyright © 2017 the American Physiological Society.

Randomized Controlled Trial of Exercise for ADHD and Disruptive Behavior Disorders

PubMed Central

Bustamante, Eduardo E.; Davis, Catherine L.; Frazier, Stacy L.; Rusch, Dana; Fogg, Louis F.; Atkins, Marc S.; Marquez, David X.

2016-01-01

Purpose To test feasibility and impact of a 10-week after-school exercise program for children with ADHD and/or disruptive behavior disorders (DBD) living in an urban poor community. Methods Children were randomized to exercise (n=19) or a comparable but sedentary attention control program (n=16). Cognitive and behavioral outcomes were collected pre-post. Intent-to-treat mixed models tested group × time and group × time × attendance interactions. Effect sizes were calculated within and between groups. Results Feasibility was evidenced by 86% retention, 60% attendance, and average 75% maximum heart rate. Group × time results were null on the primary outcome, parent-reported executive function. Among secondary outcomes, between-group effect sizes favored exercise on hyperactive symptoms (d=0.47) and verbal working memory (d=0.26), and controls on visuospatial working memory (d=-0.21) and oppositional defiant symptoms (d=-0.37). In each group, within-group effect sizes were moderate-large on most outcomes (d=0.67 to 1.60). A group × time × attendance interaction emerged on visuospatial working memory (F[1,33]=7.42, p<.05), such that attendance to the control program was related to greater improvements (r=.72, p<.01) while attendance to the exercise program was not (r=.25, p=.34). Conclusions While between-group findings on the primary outcome, parent-reported executive function, were null, between-group effect sizes on hyperactivity and visuospatial working memory may reflect adaptations to the specific challenges presented by distinct formats. Both groups demonstrated substantial within-group improvements on clinically relevant outcomes. Findings underscore the importance of programmatic features such as routines, engaging activities, behavior management strategies, and adult attention; and highlight the potential for after-school programs to benefit children with ADHD and DBD living in urban poverty where health needs are high and services resources few. PMID:26829000

Recovery of the immune system after exercise.

PubMed

Peake, Jonathan M; Neubauer, Oliver; Walsh, Neil P; Simpson, Richard J

2017-05-01

The notion that prolonged, intense exercise causes an "open window" of immunodepression during recovery after exercise is well accepted. Repeated exercise bouts or intensified training without sufficient recovery may increase the risk of illness. However, except for salivary IgA, clear and consistent markers of this immunodepression remain elusive. Exercise increases circulating neutrophil and monocyte counts and reduces circulating lymphocyte count during recovery. This lymphopenia results from preferential egress of lymphocyte subtypes with potent effector functions [e.g., natural killer (NK) cells, γδ T cells, and CD8 + T cells]. These lymphocytes most likely translocate to peripheral sites of potential antigen encounter (e.g., lungs and gut). This redeployment of effector lymphocytes is an integral part of the physiological stress response to exercise. Current knowledge about changes in immune function during recovery from exercise is derived from assessment at the cell population level of isolated cells ex vivo or in blood. This assessment can be biased by large changes in the distribution of immune cells between blood and peripheral tissues during and after exercise. Some evidence suggests that reduced immune cell function in vitro may coincide with changes in vivo and rates of illness after exercise, but more work is required to substantiate this notion. Among the various nutritional strategies and physical therapies that athletes use to recover from exercise, carbohydrate supplementation is the most effective for minimizing immune disturbances during exercise recovery. Sleep is an important aspect of recovery, but more research is needed to determine how sleep disruption influences the immune system of athletes. Copyright © 2017 the American Physiological Society.

Stair ascending–descending exercise accelerates the decrease in postprandial hyperglycemia more efficiently than bicycle exercise

PubMed Central

Takaishi, Tetsuo

2017-01-01

Objective Stair climbing–descending exercise (ST-EX) is a convenient method to increase exercise intensity. We compared the acute effect of ST-EX on lowering postprandial hyperglycemia with that of constant bicycle exercise (BI-EX) performed at the same heart rate (HR). Research design and methods Seven people with type 2 diabetes and seven with impaired glucose tolerance volunteered for this study. The step rate for ST-EX and work rate for BI-EX were individually determined to correspond to high-moderate to low-vigorous intensity (HR ~130 beats per minute). For the ST-EX trial, the subjects performed 16 repetitions of walking down one flight of stairs followed by climbing up to the starting point (~8 min in duration) 90 min after consuming a test meal. For the BI-EX trial, the subjects performed a constant pedaling exercise for the same duration at the same time after the meal. Results The reduction in blood glucose (BG) level between 90 and 105 min after a meal was significantly greater for ST-EX (–4.0±0.7mmol/L) than for BI-EX (–2.7±0.9mmol/L). The net reduction in BG between 90 and 105 min was also significantly greater for ST-EX (–3.2±0.7mmol/L) than for BI-EX (–2.0±0.6mmol/L). Serum insulin levels did not differ between the groups. Oxygen consumption for ST-EX was higher than that for BI-EX, but the blood lactate level and respiratory exchange ratio (RER) for ST-EX were lower than those for BI-EX. Conclusions Compared with BI-EX performed at the same HR, ST-EX more rapidly decreased postprandial BG level with lower blood lactate and RER responses. A short bout of ST-EX may be clinically useful to acutely ameliorate BG levels after meals. PMID:29071088

Estimation of Energy Expenditure during Treadmill Exercise via Thermal Imaging.

PubMed

Jensen, Martin Møller; Poulsen, Mathias Krogh; Alldieck, Thiemo; Larsen, Ryan Godsk; Gade, Rikke; Moeslund, Thomas Baltzer; Franch, Jesper

2016-12-01

Noninvasive imaging of oxygen uptake may provide a useful tool for the quantification of energy expenditure during human locomotion. A novel thermal imaging method (optical flow) was validated against indirect calorimetry for the estimation of energy expenditure during human walking and running. Fourteen endurance-trained subjects completed a discontinuous incremental exercise test on a treadmill. Subjects performed 4-min intervals at 3, 5, and 7 km·h (walking) and at 8, 10, 12, 14, 16, and 18 km·h (running) with 30 s of rest between intervals. Heart rate, gas exchange, and mean accelerations of ankle, thigh, wrist, and hip were measured throughout the exercise test. A thermal camera (30 frames per second) was used to quantify optical flow, calculated as the movements of the limbs relative to the trunk (internal mechanical work) and vertical movement of the trunk (external vertical mechanical work). Heart rate, gross oxygen uptake (mL·kg·min) together with gross and net energy expenditure (J·kg·min) rose with increasing treadmill velocities, as did optical flow measurements and mean accelerations (g) of ankle, thigh, wrist, and hip. Oxygen uptake was linearly correlated with optical flow across all exercise intensities (R = 0.96, P < 0.0001; V˙O2 [mL·kg·min] = 7.35 + 9.85 × optical flow [arbitrary units]). Only 3-4 s of camera recording was required to estimate an optical flow value at each velocity. Optical flow measurements provide an accurate estimation of energy expenditure during horizontal walking and running. The technique offers a novel experimental method of estimating energy expenditure during human locomotion, without use of interfering equipment attached to the subject.

Effect of recovery duration from prior exhaustive exercise on the parameters of the power-duration relationship.

PubMed

Ferguson, C; Rossiter, H B; Whipp, B J; Cathcart, A J; Murgatroyd, S R; Ward, S A

2010-04-01

The physiological equivalents of the curvature constant (W') of the high-intensity power-duration (P-t(LIM)) relationship are poorly understood, although they are presumed to reach maxima/minima at exhaustion. In an attempt to improve our understanding of the determinants of W', we therefore aimed to determine its recovery kinetics following exhaustive exercise (which depletes W') concomitantly with those of O(2) uptake (V(O(2)), a proxy for the kinetics of phosphocreatine replenishment) and blood lactate concentration ([L(-)]). Six men performed cycle-ergometer exercise to t(LIM): a ramp and four constant-load tests, at different work rates, for estimation of lactate threshold, W', critical power (CP), and maximum V(O(2)). Three further exhausting tests were performed at different work rates, each preceded by an exhausting "conditioning" bout, with intervening recoveries of 2, 6, and 15 min. Neither prior exhaustion nor recovery duration altered V(O(2)) or [L(-)] at t(LIM). Postconditioning, the P-t(LIM) relationship remained well characterized by a hyperbola, with CP unchanged. However, W' recovered to 37 +/- 5, 65 +/- 6, and 86 +/- 4% of control following 2, 6, and 15 min of intervening recovery, respectively. The W' recovery was curvilinear [interpolated half time (t(1/2)) = 234 +/- 32 s] and appreciably slower than V(O(2)) recovery (t(1/2) = 74 +/- 2 s) but faster than [L(-)] recovery (t(1/2) = 1,366 +/- 799 s). This suggests that W' determines supra-CP exercise tolerance, its restitution kinetics are not a unique function of phosphocreatine concentration or arterial [L(-)], and it is unlikely to simply reflect a finite energy store that becomes depleted at t(LIM).

Poor glycaemic control is associated with reduced exercise performance and oxygen economy during cardio-pulmonary exercise testing in people with type 1 diabetes.

PubMed

Moser, Othmar; Eckstein, Max L; McCarthy, Olivia; Deere, Rachel; Bain, Stephen C; Haahr, Hanne L; Zijlstra, Eric; Bracken, Richard M

2017-01-01

To explore the impact of glycaemic control (HbA 1c ) on functional capacity during cardio-pulmonary exercise testing in people with type 1 diabetes. Sixty-four individuals with type 1 diabetes (age: 34 ± 8 years; 13 females, HbA 1c : 7.8 ± 1% (62 ± 13 mmol/mol), duration of diabetes: 17 ± 9 years) performed a cardio-pulmonary cycle ergometer exercise test until volitional exhaustion. Stepwise linear regression was used to explore relationships between HbA 1c and cardio-respiratory data with p ≤ 0.05. Furthermore, participants were divided into quartiles based on HbA 1c levels and cardio-respiratory data were analysed by one-way ANOVA. Multiple regression analysis was performed to explore the relationships between changes in time to exhaustion and cardio-respiratory data. Data were adjusted for confounder. HbA 1c was related to time to exhaustion and oxygen consumption at the power output elicited at the sub-maximal threshold of the heart rate turn point (r = 0.47, R 2  = 0.22, p = 0.03). Significant differences were found at time to exhaustion between Q I vs. Q IV and at oxygen consumption at the power output elicited at the heart rate turn point between Q I vs. Q II and Q I vs. Q IV (p < 0.05). Changes in oxygen uptake, power output and in oxygen consumption at the power output elicited at the heart rate turn point and at maximum power output explained 55% of the variance in time to exhaustion ( r  = 0.74, R 2  = 0.55, p < 0.01). Poor glycaemic control is related to less economical use of oxygen at sub-maximal work rates and an earlier time to exhaustion during cardio-pulmonary exercise testing. However, exercise training could have the same potential to counteract the influence of poor glycaemic control on functional capacity. Trial registration NCT01704417. Date of registration: October 11, 2012.

Ginseng supplementation does not change lactate threshold and physical performances in physically active Thai men.

PubMed

Kulaputana, Onanong; Thanakomsirichot, Siriwan; Anomasiri, Wilai

2007-06-01

Ginseng has been one of the most popular herbs said to improve human exercise performance. Unclear and anecdotal information is known about the effect of ginseng on lactate threshold and aerobic performance in humans. The purpose of the present study was to investigate the effect of ginseng supplementation on lactate threshold in physically active young men. Sixty men from the Naval Medical Corps, Royal Thai Navy, aged 17- 22 years old, were randomized into either the ginseng (n = 30) or placebo (n = 30) group. The ginseng group took 3 grams of 100% ginseng orally, while the placebo group took an equal amount of lactose powder each day, for 8 weeks. Blood lactic acid levels for determination of lactate threshold (LT) were measured during an incremental cycle ergometer work. LT exercise performance, and heart rate (HR) responses to exercise were determined at baseline and after 8 weeks of ginseng and placebo consumption. Substrate oxidation rates during steady state exercise were assessed upon study completion. Selected markers for liver and kidney functions, including serum aspartate aminotransferase, alanine aminotransferase, blood urea nitrogen, and creatinine were monitored for possible side effects of ginseng. L T before and after 8 weeks of supplementation in the ginseng group (164.5 +/- 32.8 and 170.9 +/- 26.4 watts), and in the placebo group (163.7 + 25.1 and 163.7 + 17.3 watts) were not different (p = 0.448). Both groups had a similar pattern of exercise heart rate (p = 0.918), total exercise time (p = 0.241), and peak power output (p = 0.411). After 8 weeks, the magnitude of difference between ginseng and placebo groups on oxidation rates of fat (3.82 +/- 10.0 cal. kg(-1). min(-1), p = 0.704) or carbohydrate (4.36 +/- 12.6 cal. kg(-1). min(-1), p = 0.731) was not statistically significant. There were no abnormal changes of markers of liver and renal functions after ginseng administration. Daily administration of 3 g of ginseng for an 8-week period did not improve LT nor did it affect physical performances. Therefore, ginseng supplementation did not exert an ergogenic property on aerobic fitness enhancement in well-fit individuals.

[Heart rate variability and physical exercise. Current status].

PubMed

Hottenrott, Kuno; Hoos, Olaf; Esperer, Hans Dieter

2006-09-01

Heart rate variability (HRV) has long been used in risk stratification for sudden cardiac death and diabetic autonomic neuropathy. In recent years, both time and frequency domain indices of HRV also gained increasing interest in sports and training sciences. In these fields, HRV is currently used for the noninvasive assessment of autonomic changes associated with short-term and long-term endurance exercise training in both leisure sports activity and high-performance training. Furthermore, HRV is being investigated as a diagnostic marker of overreaching and overtraining.A large body of evidence shows that, in healthy subjects and cardiovascular patients of all ages (up to an age of 70 years), regular aerobic training usually results in a significant improvement of overall as well as instantaneous HRV. These changes, which are accompanied by significant reductions in heart rates both at rest and during submaximal exercise, reflect an increase in autonomic efferent activity and a shift in favor of enhanced vagal modulation of the cardiac rhythm. Regular aerobic training of moderate volume and intensity over a minimum period of 3 months seems to be necessary to ensure these effects, which might be associated with a prognostic benefit regarding overall mortality.At present, available data does not allow for final conclusions with respect to the usefulness of traditional HRV indices in assessing an individual's exercise performance and monitoring training load. The discrepant results published so far are due to several factors including insufficient study size and design, and different HRV methods. Large-sized and prospectively designed studies are necessary for clarification. It also remains to be seen, whether the traditional HRV indices prove useful in the diagnosis of overreaching and overtraining. Preliminary results, though promising, need to be confirmed in larger cohorts.A basic problem in HRV analysis is nonstationarity of the heart rate signal, which holds particularly true for exercise conditions. Whether, in these conditions, more robust nonlinear HRV methods offer a benefit has to be established in further work.

Effects of a Short-Term High-Nitrate Diet on Exercise Performance

PubMed Central

Porcelli, Simone; Pugliese, Lorenzo; Rejc, Enrico; Pavei, Gaspare; Bonato, Matteo; Montorsi, Michela; La Torre, Antonio; Rasica, Letizia; Marzorati, Mauro

2016-01-01

It has been reported that nitrate supplementation can improve exercise performance. Most of the studies have used either beetroot juice or sodium nitrate as a supplement; there is lack of data on the potential ergogenic benefits of an increased dietary nitrate intake from a diet based on fruits and vegetables. Our aim was to assess whether a high-nitrate diet increases nitric oxide bioavailability and to evaluate the effects of this nutritional intervention on exercise performance. Seven healthy male subjects participated in a randomized cross-over study. They were tested before and after 6 days of a high (HND) or control (CD) nitrate diet (~8.2 mmol∙day−1 or ~2.9 mmol∙day−1, respectively). Plasma nitrate and nitrite concentrations were significantly higher in HND (127 ± 64 µM and 350 ± 120 nM, respectively) compared to CD (23 ± 10 µM and 240 ± 100 nM, respectively). In HND (vs. CD) were observed: (a) a significant reduction of oxygen consumption during moderate-intensity constant work-rate cycling exercise (1.178 ± 0.141 vs. 1.269 ± 0.136 L·min−1); (b) a significantly higher total muscle work during fatiguing, intermittent sub-maximal isometric knee extension (357.3 ± 176.1 vs. 253.6 ± 149.0 Nm·s·kg−1); (c) an improved performance in Repeated Sprint Ability test. These findings suggest that a high-nitrate diet could be a feasible and effective strategy to improve exercise performance. PMID:27589795

High intensity interval exercise is an effective alternative to moderate intensity exercise for improving glucose tolerance and insulin sensitivity in adolescent boys.

PubMed

Cockcroft, Emma J; Williams, Craig A; Tomlinson, Owen W; Vlachopoulos, Dimitris; Jackman, Sarah R; Armstrong, Neil; Barker, Alan R

2015-11-01

High-intensity interval exercise (HIIE) may offer a time efficient means to improve health outcomes compared to moderate-intensity exercise (MIE). This study examined the acute effect of HIIE compared to a work-matched bout of MIE on glucose tolerance, insulin sensitivity (IS), resting fat oxidation and exercise enjoyment in adolescent boys. Within-measures design with counterbalanced experimental conditions. Nine boys (14.2 ± 0.4 years) completed three conditions on separate days in a counterbalanced order: (1) HIIE; (2) work matched MIE, both on a cycle ergometer; and (3) rest (CON). An oral glucose tolerance test (OGTT) was performed after exercise or rest and the area under curve (AUC) responses for plasma [glucose] and [insulin] were calculated, and IS estimated (Cederholm index). Energy expenditure and fat oxidation were measured following the OGTT using indirect calorimetry. Exercise enjoyment was assessed using the Physical Activity Enjoyment Scale. The incremental AUC (iAUC) for plasma [glucose] was reduced following both MIE (-23.9%, P = 0.013, effect size [ES] = -0.64) and HIIE (-28.9%, P=0.008, ES = -0.84) compared to CON. The iAUC for plasma [insulin] was lower for HIIE (-24.2%, P = 0.021, ES = -0.71) and MIE (-29.1%, P = 0.012, ES = -0.79) compared to CON. IS increased by 11.2% after HIIE (P = 0.03, ES = 0.76) and 8.4% after MIE (P = 0.10, ES = 0.58). There was a trend for an increase in fat oxidation following HIIE (P = 0.097, ES = 0.70). Both HIIE and MIE were rated as equally enjoyable (P > 0.05, ES < 0.01). A single bout of time efficient HIIE is an effective alternative to MIE for improving glucose tolerance and IS in adolescent boys immediately after exercise. Copyright © 2014 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Effects of Aerobic Exercise Based upon Heart Rate at Aerobic Threshold in Obese Elderly Subjects with Type 2 Diabetes

PubMed Central

Donini, Lorenzo Maria

2015-01-01

In obese diabetic subjects, a correct life style, including diet and physical activity, is part of a correct intervention protocol. Thus, the aim of this study was to evaluate the effects of aerobic training intervention, based on heart rate at aerobic gas exchange threshold (AerTge), on clinical and physiological parameters in obese elderly subjects with type 2 diabetes (OT2DM). Thirty OT2DM subjects were randomly assigned to an intervention (IG) or control group (CG). The IG performed a supervised aerobic exercise training based on heart rate at AerTge whereas CG maintained their usual lifestyle. Anthropometric measures, blood analysis, peak oxygen consumption (V˙O2peak), metabolic equivalent (METpeak), work rate (WRpeak), and WRAerTge were assessed at baseline and after intervention. After training, patients enrolled in the IG had significantly higher (P < 0.001) V˙O2peak, METpeak, WRpeak, and WRAerTge and significantly lower (P < 0.005) weight, BMI, %FM, and waist circumference than before intervention. Both IG and CG subjects had lower glycated haemoglobin levels after intervention period. No significant differences were found for all the other parameters between pre- and posttraining and between groups. Aerobic exercise prescription based upon HR at AerTge could be a valuable physical intervention tool to improve the fitness level and metabolic equilibrium in OT2DM patients. PMID:26089890

Influence of work clothing on physiological responses and performance during treadmill exercise and the Wildland Firefighter Pack Test.

PubMed

Phillips, Devin B; Ehnes, Cameron M; Welch, Bradley G; Lee, Lauren N; Simin, Irina; Petersen, Stewart R

2018-04-01

This study investigated physiological responses and performance during three separate exercise challenges (Parts I, II, and III) with wildland firefighting work clothing ensemble (boots and coveralls) and a 20.4 kg backpack in four conditions: U-EX (no pack, exercise clothing); L-EX (pack, exercise clothing); U-W (no pack, work clothing); and, L-W (pack and work clothing). Part I consisted of randomly-ordered graded exercise tests, on separate days, in U-EX, L-EX and L-W conditions. Part II consisted of randomly-ordered bouts of sub-maximal treadmill exercise in the four conditions. In Part III, subjects completed, in random-order on separate days, 4.83 km Pack Tests in L-EX or L-W conditions. In Part I, peak oxygen uptake was reduced (p < .05) in L-W. In Part II, mass-specific oxygen uptake was significantly higher in both work clothing conditions. In Part III, Pack Test time was slower (p < .05) in L-W. These results demonstrate the negative impact of work clothing and load carriage on physiological responses to exercise and performance. Copyright © 2017 Elsevier Ltd. All rights reserved.

Exercise following Mental Work Prevented Overeating.

PubMed

Neumeier, William H; Goodner, Emily; Biasini, Fred; Dhurandhar, Emily J; Menear, Kristi S; Turan, Bulent; Hunter, Gary R

2016-09-01

Mental work may promote caloric intake, whereas exercise may offset positive energy balance by decreasing energy intake and increasing energy expenditure. This study aimed to replicate previous findings that mental work increases caloric intake compared with a rest condition and assess whether exercise after mental work can offset this effect. Thirty-eight male and female university students were randomly assigned to mental work + rest (MW + R) or mental work + exercise (MW + E). Participants also completed a baseline rest (BR) visit consisting of no mental work or exercise. Visit order was counterbalanced. During the MW + R or MW + E visit, participants completed a 20-min mental task and either a 15-min rest (MW + R) or a 15-min interval exercise (MW + E). Each visit ended with an ad libitum pizza lunch. A two-way repeated-measures ANOVA was used to compare eating behavior between groups. Participants in the MW + R condition consumed an average of 100 more kilocalories compared with BR (633.3 ± 72.9 and 533.9 ± 67.7, respectively, P = 0.02), and participants in MW + E consumed an average of 25 kcal less compared with BR (432.3 ± 69.2 and 456.5 ± 64.2, respectively, P > 0.05). When including the estimated energy expenditure of exercise in the MW + E conditions, participants were in negative energy balance by an average of 98.5 ± 41.5 kcal, resulting in a significant difference in energy balance between the two groups (P = 0.001). An acute bout of interval exercise after mental work resulted in significantly decreased food consumption compared with a nonexercise condition. These results suggest that an acute bout of exercise may be used to offset positive energy balance induced by mental tasks.

Results of Skylab medical experiment M171: Metabolic activity

NASA Technical Reports Server (NTRS)

Michel, E. L.; Rummel, J. A.; Sawin, C. F.; Buderer, M. C.; Lem, J. D.

1974-01-01

The experiment was conducted to establish whether man's ability to perform mechanical work would be progressively altered as a result of exposure to the weightless environment of space flight. The Skylab crewmen exercised on a bicycle ergometer at workloads approximating 25, 50, and 75 percent of their maximum aerobic capacity. The physiological parameters monitored were respiratory gas exchange, blood pressure, and vectorcardiogram/heart rate. The results of these tests indicate that the crewmen had no significant decrement in their responses to exercise during their exposure to zero gravity. The results of the third manned Skylab mission (Skylab 4) are presented and a comparison is made of the overall results obtained from the three successively longer Skylab manned missions. The Skylab 4 crewmembers' 84-day in-flight responses to exercise were no worse and were probably better than the responses of the crewmen on the first two Skylab missions. Indications that exercise was an important contributing factor in maintaining this response are discussed.

Exercise Responses after Inactivity

NASA Technical Reports Server (NTRS)

Convertino, Victor A.

1986-01-01

The exercise response after bed rest inactivity is a reduction in the physical work capacity and is manifested by significant decreases in oxygen uptake. The magnitude of decrease in maximal oxygen intake V(dot)O2max is related to the duration of confinement and the pre-bed-rest level of aerobic fitness; these relationships are relatively independent of age and gender. The reduced exercise performance and V(dot)O2max following bed rest are associated with various physiological adaptations including reductions in blood volume, submaximal and maximal stroke volume, maximal cardiac output, sceletal muscle tone and strength, and aerobic enzyme capacities, as well as increases in venous compliance and submaximal and maximal heart rate. This reduction in physiological capacity can be partially restored by specific countermeasures that provide regular muscular activity or orhtostatic stress or both during the bed rest exposure. The understanding of these physiological and physical responses to exercise following bed rest inactivity has important implications for the solution to safety and health problems that arise in clinical medicine, aerospace medicine, sedentary living, and aging.

Variability in heart rate recovery measurements over 1 year in healthy, middle-aged adults.

PubMed

Mellis, M G; Ingle, L; Carroll, S

2014-02-01

This study assessed the longer-term (12-month) variability in post-exercise heart rate recovery following a submaximal exercise test. Longitudinal data was analysed for 97 healthy middle-aged adults (74 male, 23 female) from 2 occasions, 12 months apart. Participants were retrospectively selected if they had stable physical activity habits, submaximal treadmill fitness and anthropometric measurements between the 2 assessment visits. A submaximal Bruce treadmill test was performed to at least 85% age-predicted maximum heart rate. Absolute heart rate and Δ heart rate recovery (change from peak exercise heart rate) were recorded for 1 and 2 min post-exercise in an immediate supine position. Heart rate recovery at both time-points was shown to be reliable with intra-class correlation coefficient values ≥ 0.714. Absolute heart rate 1-min post-exercise showed the strongest agreement between repeat tests (r = 0.867, P < 0.001). Lower coefficient of variation (≤ 10.2%) and narrower limits of agreement were found for actual heart rate values rather than Δ heart rate recovery, and for 1-min rather than 2-min post-exercise recovery time points. Log-transformed values generated better variability with acceptable coefficient of variation for all measures (2.2-10%). Overall, 1 min post-exercise heart rate recovery data had least variability over the 12-month period in apparently healthy middle-aged adults. © Georg Thieme Verlag KG Stuttgart · New York.

Muscle metabolic and neuromuscular determinants of fatigue during cycling in different exercise intensity domains

PubMed Central

Black, Matthew I.; Jones, Andrew M.; Blackwell, Jamie R.; Bailey, Stephen J.; Wylie, Lee J.; McDonagh, Sinead T. J.; Thompson, Christopher; Kelly, James; Sumners, Paul; Mileva, Katya N.; Bowtell, Joanna L.

2017-01-01

Lactate or gas exchange threshold (GET) and critical power (CP) are closely associated with human exercise performance. We tested the hypothesis that the limit of tolerance (Tlim) during cycle exercise performed within the exercise intensity domains demarcated by GET and CP is linked to discrete muscle metabolic and neuromuscular responses. Eleven men performed a ramp incremental exercise test, 4–5 severe-intensity (SEV; >CP) constant-work-rate (CWR) tests until Tlim, a heavy-intensity (HVY; GET) CWR test until Tlim, and a moderate-intensity (MOD; 0.05) muscle metabolic milieu (i.e., low pH and [PCr] and high [lactate]) was attained at Tlim (approximately 2–14 min) for all SEV exercise bouts. The muscle metabolic perturbation was greater at Tlim following SEV compared with HVY, and also following SEV and HVY compared with MOD (all P < 0.05). The normalized M-wave amplitude for the vastus lateralis (VL) muscle decreased to a similar extent following SEV (−38 ± 15%), HVY (−68 ± 24%), and MOD (−53 ± 29%), (P > 0.05). Neural drive to the VL increased during SEV (4 ± 4%; P < 0.05) but did not change during HVY or MOD (P > 0.05). During SEV and HVY, but not MOD, the rates of change in M-wave amplitude and neural drive were correlated with changes in muscle metabolic ([PCr], [lactate]) and blood ionic/acid-base status ([lactate], [K+]) (P < 0.05). The results of this study indicate that the metabolic and neuromuscular determinants of fatigue development differ according to the intensity domain in which the exercise is performed. NEW & NOTEWORTHY The gas exchange threshold and the critical power demarcate discrete exercise intensity domains. For the first time, we show that the limit of tolerance during whole-body exercise within these domains is characterized by distinct metabolic and neuromuscular responses. Fatigue development during exercise greater than critical power is associated with the attainment of consistent “limiting” values of muscle metabolites, whereas substrate availability and limitations to muscle activation may constrain performance at lower intensities. PMID:28008101

Effect of a moderate caffeine dose on endurance cycle performance and thermoregulation during prolonged exercise in the heat.

PubMed

Beaumont, Ross E; James, Lewis J

2017-11-01

This study investigated the influence of a moderate caffeine dose on endurance cycle performance and thermoregulation during prolonged exercise in high ambient temperature. Double-blind cross-over study. Eight healthy, recreationally active males (mean±SD; age: 22±1 years; body mass: 71.1±8.5kg; VO 2peak : 55.9±5.8mLkg -1 min -1 ; W max : 318±37W) completed one VO 2peak test, one familiarisation trial and two experimental trials. After an overnight fast, participants ingested a placebo or a 6mgkg -1 caffeine dose 60min before exercise. The exercise protocol consisted of 60min of cycle exercise at 55% W max , followed by a 30min performance task (total kJ produced) in 30°C and 50% RH. Performance was enhanced (Cohen's d effect size=0.22) in the caffeine trial (363.8±47.6kJ) compared with placebo (353.0±49.0kJ; p=0.004). Caffeine did not influence core (p=0.188) or skin temperature (p=0.577) during exercise. Circulating prolactin (p=0.572), cortisol (p=0.842) and the estimated rates of fat (p=0.722) and carbohydrate oxidation (p=0.454) were also similar between trial conditions. Caffeine attenuated perceived exertion during the initial 60min of exercise (p=0.033), with no difference in thermal stress across trials (p=0.911). Supplementation with 6mgkg -1 caffeine improved endurance cycle performance in a warm environment, without differentially influencing thermoregulation during prolonged exercise at a fixed work-rate versus placebo. Therefore, moderate caffeine doses which typically enhance performance in temperate environmental conditions also appear to benefit endurance performance in the heat. Copyright © 2017 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Activity restriction in mild COPD: a challenging clinical problem

PubMed Central

O’Donnell, Denis E; Gebke, Kevin B

2014-01-01

Dyspnea, exercise intolerance, and activity restriction are already apparent in mild chronic obstructive pulmonary disease (COPD). However, patients may not seek medical help until their symptoms become troublesome and persistent and significant respiratory impairment is already present; as a consequence, further sustained physical inactivity may contribute to disease progression. Ventilatory and gas exchange impairment, cardiac dysfunction, and skeletal muscle dysfunction are present to a variable degree in patients with mild COPD, and collectively may contribute to exercise intolerance. As such, there is increasing interest in evaluating exercise tolerance and physical activity in symptomatic patients with COPD who have mild airway obstruction, as defined by spirometry. Simple questionnaires, eg, the modified British Medical Research Council dyspnea scale and the COPD Assessment Test, or exercise tests, eg, the 6-minute or incremental and endurance exercise tests can be used to assess exercise performance and functional status. Pedometers and accelerometers are used to evaluate physical activity, and endurance tests (cycle or treadmill) using constant work rate protocols are used to assess the effects of interventions such as pulmonary rehabilitation. In addition, alternative outcome measurements, such as tests of small airway dysfunction and laboratory-based exercise tests, are used to measure the extent of physiological impairment in individuals with persistent dyspnea. This review describes the mechanisms of exercise limitation in patients with mild COPD and the interventions that can potentially improve exercise tolerance. Also discussed are the benefits of pulmonary rehabilitation and the potential role of pharmacologic treatment in symptomatic patients with mild COPD. PMID:24940054

Effect of exercise on cigarette cravings and ad libitum smoking following concurrent stressors.

PubMed

Fong, Angela J; De Jesus, Stefanie; Bray, Steven R; Prapavessis, Harry

2014-10-01

The health consequences of smoking are well documented, yet quit rates are modest. While exercise has supported decreased cravings and withdrawal symptoms in temporarily abstinent smokers, it has yet to be applied when smokers are experiencing concurrent stressors. This study examined the effect of an acute bout of moderate intensity exercise on cravings (primary outcome) and ad libitum smoking (secondary outcome) following concurrent stressors (i.e., temporary abstinence and environmental manipulation-Stroop cognitive task+cue-elicited smoking stimuli). Twenty-five smokers (>10cig/day; Mean age=37.4years) were randomized into either exercise (n=12) or passive sitting conditions. A repeated measure (RM) ANOVA showed that psychological withdrawal symptoms (a measure of distress) were significantly exacerbated after temporary abstinence and then again after the environmental manipulation for all participants (p<.0001, η(2)=.50). Furthermore, a treatment by time RM ANOVA revealed decreases in psychological withdrawal symptoms for only the exercise condition (p<.001, η(2)=.42). A treatment by time RM ANOVA also revealed craving reductions for only the exercise condition (p<.0001, η(2)=.82). Exercise had no effect on ad libitum smoking. This is the first study to use a lab-based scenario with high ecological validity to show that an acute bout of exercise can reduce cravings following concurrent stressors. Future work is now needed where momentary assessment is used in people's natural environment to examine changes in cigarette cravings following acute bouts of exercise. Copyright © 2014 Elsevier Ltd. All rights reserved.

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

PubMed

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

2015-11-01

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

Exercise/recreation facility for a Lunar or Mars analog

NASA Technical Reports Server (NTRS)

1991-01-01

Discussed here is a project to design an exercise/recreation station for an earth based simulator of a lunar or Martian habitat. Specifically, researchers designed a stationary bicycle that will help people keep fit and prevent muscular atrophy while stationed in space. To help with motivation and provide an element of recreation during the workout, the bicycle is enhanced by a virtual reality system. The system will simulate various riding situations and the choice of mountain bike or road bike. The bike employs a magnetic brake that provides continuously changing tension to simulate actual riding conditions. This braking system will be interfaced directly with the virtual reality system. Also integrated into the virtual reality system will be a monitoring system that regulates heart rate, work rate, and other functions during the course of the session.

Review of attrition and adherence in exercise studies following hematopoietic stem cell transplantation.

PubMed

Hacker, Eileen Danaher; Mjukian, Maral

2014-04-01

Implementing exercise programs in people receiving high-dose chemotherapy followed by bone marrow (BMT) or hematopoietic stem cell transplantation (SCT) presents unique challenges. This review examines subject attrition rates and reasons for attrition as well as adherence to exercise interventions following BMT/SCT. Studies published between January 1985 and December 2012 that prospectively tested an exercise intervention following BMT or SCT were included in the review. Evaluation criteria included: (1) exercise modality; (2) the amount of supervision required to implement the intervention; (3) timing of the intervention; (4) subject attrition rates and reasons for attrition; and (5) exercise adherence rates. Of the 20 studies reviewed, most tested an aerobic exercise intervention or a combination of aerobic and strength training. Supervised exercise sessions were more commonly used than unsupervised sessions. The overall attrition rate was 18% for the 998 subjects enrolled in the studies. Major reasons for attrition included death, change in health status, protocol issues, personal issues with subjects, and lost to follow-up/no reason provided. Authors of supervised exercise programs rarely published exercise adherence information. Unsupervised exercise programs relied mainly on self-report to document adherence. Exercise research following BMT/SCT is becoming more sophisticated as researchers build upon the expanding literature base. Questions regarding subject attrition and adherence to exercise interventions must be addressed to identify interventions that are likely to be successful when translated into clinical practice. Subject attrition from exercise studies following BMT/SCT is relatively low. Adherence information for exercise interventions needs to be regularly addressed. Copyright © 2013 Elsevier Ltd. All rights reserved.

Long-term exercise adherence after public health training in at-risk adults.

PubMed

Saida, Trine Gro Riktrup Hansen; Juul Sørensen, Tina; Langberg, Henning

2017-07-01

Sustainment of healthy exercise behavior is essential in preventing cardiovascular disease and diabetes. Few studies have explored long-term exercise adherence after an exercise referral scheme. The objective of this study was to examine 12-month exercise adherence after an exercise intervention program. This was a pragmatic follow-up study in at-risk people performed between June 2012 and January 2014. The main outcome measure was self-reported single-item exercise adherence. Secondary outcomes were change in exercise level, quality of life rated on a visual analog scale and self-rated health. Predictors of long-term exercise adherence were assessed by logistic regression, estimating crude odds-ratios (OR) and 95% confidence intervals (95% CIs) and adjusting for age, gender, education, smoking, moderate and vigorous exercise. In total, 214 adults (mean age 58.8±11.97 years, 71% women) participated in the study and received a 12-week training intervention: 62% had hypertension, 64% dyslipidemia and 15% impaired glucose tolerance. Attrition rate was 84% (n=179). During the 12-month follow-up, 48% (n=85) reported long-term exercise adherence. The main predictors of long-term exercise adherence were participation in sport activities at baseline (adjusted odds-ratio [aOR] 4.22, 95% CI 1.72-10.40), self-rated health (aOR 2.60, 1.00-6.75) and quality of life (aOR 2.39, 1.03-5.54). Long-term non-adherence was associated with low education (<10 years; aOR 3.27, 1.14-9.43) and age<50 years (aOR 3.53, 1.32-9.43). In this pragmatic study, long-term exercise adherence was associated with participation in sport activities and self-rated health at baseline. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Electric motor assisted bicycle as an aerobic exercise machine.

PubMed

Nagata, T; Okada, S; Makikawa, M

2012-01-01

The goal of this study is to maintain a continuous level of exercise intensity around the aerobic threshold (AT) during riding on an electric motor assisted bicycle using a new control system of electrical motor assistance which uses the efficient pedaling rate of popular bicycles. Five male subjects participated in the experiment, and the oxygen uptake was measured during cycling exercise using this new pedaling rate control system of electrical motor assistance, which could maintain the pedaling rate within a specific range, similar to that in previous type of electrically assisted bicycles. Results showed that this new pedaling rate control system at 65 rpm ensured continuous aerobic exercise intensity around the AT in two subjects, and this intensity level was higher than that observed in previous type. However, certain subjects were unable to maintain the expected exercise intensity because of their particular cycling preferences such as the pedaling rate. It is necessary to adjust the specific pedaling rate range of the electrical motor assist control according to the preferred pedaling rate, so that this system becomes applicable to anyone who want continuous aerobic exercise.

Work volume and strength training responses to resistive exercise improve with periodic heat extraction from the palm.

PubMed

Grahn, Dennis A; Cao, Vinh H; Nguyen, Christopher M; Liu, Mengyuan T; Heller, H Craig

2012-09-01

Body core cooling via the palm of a hand increases work volume during resistive exercise. We asked: (a) "Is there a correlation between elevated core temperatures and fatigue onset during resistive exercise?" and (b) "Does palm cooling between sets of resistive exercise affect strength and work volume training responses?" Core temperature was manipulated by 30-45 minutes of fixed load and duration treadmill exercise in the heat with or without palm cooling. Work volume was then assessed by 4 sets of fixed load bench press exercises. Core temperatures were reduced and work volumes increased after palm cooling (Control: Tes = 39.0 ± 0.1° C, 36 ± 7 reps vs. Cooling: Tes = 38.4 ± 0.2° C, 42 ± 7 reps, mean ± SD, n = 8, p < 0.001). In separate experiments, the impact of palm cooling on work volume and strength training responses were assessed. The participants completed biweekly bench press or pull-up exercises for multiple successive weeks. Palm cooling was applied for 3 minutes between sets of exercise. Over 3 weeks of bench press training, palm cooling increased work volume by 40% (vs. 13% with no treatment; n = 8, p < 0.05). Over 6 weeks of pull-up training, palm cooling increased work volume by 144% in pull-up experienced subjects (vs. 5% over 2 weeks with no treatment; n = 7, p < 0.001) and by 80% in pull-up naïve subjects (vs. 20% with no treatment; n = 11, p < 0.01). Strength (1 repetition maximum) increased 22% over 10 weeks of pyramid bench press training (4 weeks with no treatment followed by 6 weeks with palm cooling; n = 10, p < 0.001). These results verify previous observations about the effects of palm cooling on work volume, demonstrate a link between core temperature and fatigue onset during resistive exercise, and suggest a novel means for improving strength and work volume training responses.

Effect of energy drink dose on exercise capacity, heart rate recovery and heart rate variability after high-intensity exercise.

PubMed

An, Sang Min; Park, Jong Suk; Kim, Sang Ho

2014-03-01

The purpose of this research was to investigate the effects of exercise capacity, heart rate recovery and heart rate variability after high-intensity exercise on caffeine concentration of energy drink. The volunteers for this study were 15 male university student. 15 subjects were taken basic physical examinations such as height, weight and BMI before the experiment. Primary tests were examined of VO2max per weight of each subjects by graded exercise test using Bruce protocol. Each of five subject was divided 3 groups (CON, ECGⅠ, ECGⅡ) by matched method based on weight and VO2max per weight what gained of primary test for minimize the differences of exercise capacity and ingestion of each groups. For the secondary tests, the groups of subjects were taken their materials before and after exercise as a blind test. After the ingestion, subjects were experimented on exercise test of VO2max 80% by treadmill until the all-out. Heart rate was measured by 1minute interval, and respiratory variables were analyzed VO2, VE, VT, RR and so on by automatic respiratory analyzer. And exercise exhaustion time was determined by stopwatch. Moreover, HRV was measured after exercise and recovery 3 min. Among the intake groups, ECGⅡ was showed the longest of exercise exhaustion time more than CON group (p = .05). Result of heart rate during exercise according to intake groups, there was significant differences of each time (p < .001), however, not significant differences of each groups and group verse time (p > .05). Result of RPE during exercise according to intake groups, there was significant differences of each time (p < .001), however, not significant differences of each groups and group verse time (p > .05). In conclusion, EDGⅡ showed the significant increase of exercise exhaustion time more than CON group (p=.05) and not significant differences in HR, RPE, RER, HRV, HRR, blood pressure (p > .05). Therefore, 2.5 mg/kg(-1) ingestion of energy drink might be positive effect to increase exercise performance capacity without side-effect in cardiovascular disease.

The Effects of the Nintendo Wii Exercise Program on Chronic Work-related Low Back Pain in Industrial Workers.

PubMed

Park, Ji-Hyuk; Lee, Sang-Heon; Ko, Dae-Sik

2013-08-01

[Purpose] The purpose of this study was to investigate the effects of a Nintendo Wii exercise program on chronic work-related LBP compared with stability exercise. [Methods] Twenty-four workers participated in this study. All of the participants were diagnosed with chronic LBP by a physician. Participants were randomly assigned to three groups: a control group (CG), lumbar stabilization exercise group (LSE), and Nintendo Wii exercise group (NWE). Participants were treated 3 times a week for 8 weeks. Each session lasted 30 minutes. [Results] The results demonstrated that exercise programs improved significantly physical functions related to LBP. In health-related QOL, the Nintendo Wii exercise program significantly improved both the mental and physical health composites, but other groups had significant improvement only in the physical health composite. [Conclusion] The Nintendo Wii exercise program could be a biopsychosocial intervention for work-related LBP in factory workers.

The Effects of the Nintendo Wii Exercise Program on Chronic Work-related Low Back Pain in Industrial Workers

PubMed Central

Park, Ji-Hyuk; Lee, Sang-Heon; Ko, Dae-Sik

2013-01-01

[Purpose] The purpose of this study was to investigate the effects of a Nintendo Wii exercise program on chronic work-related LBP compared with stability exercise. [Methods] Twenty-four workers participated in this study. All of the participants were diagnosed with chronic LBP by a physician. Participants were randomly assigned to three groups: a control group (CG), lumbar stabilization exercise group (LSE), and Nintendo Wii exercise group (NWE). Participants were treated 3 times a week for 8 weeks. Each session lasted 30 minutes. [Results] The results demonstrated that exercise programs improved significantly physical functions related to LBP. In health-related QOL, the Nintendo Wii exercise program significantly improved both the mental and physical health composites, but other groups had significant improvement only in the physical health composite. [Conclusion] The Nintendo Wii exercise program could be a biopsychosocial intervention for work-related LBP in factory workers. PMID:24259899

Investigating the exercise-prescription practices of nurses working in inpatient mental health settings.

PubMed

Stanton, Robert; Happell, Brenda; Reaburn, Peter

2015-04-01

Nurses working in mental health are well positioned to prescribe exercise to people with mental illness. However, little is known regarding their exercise-prescription practices. We examined the self-reported physical activity and exercise-prescription practices of nurses working in inpatient mental health facilities. Thirty-four nurses completed the Exercise in Mental Illness Questionnaire - Health Practitioner Version. Non-parametric bivariate statistics revealed no relationship between nurses' self-reported physical activity participation and the frequency of exercise prescription for people with mental illness. Exercise-prescription parameters used by nurses are consistent with those recommended for both the general population and for people with mental illness. A substantial number of barriers to effective exercise prescription, including lack of training, systemic issues (such as prioritization and lack of time), and lack of consumer motivation, impact on the prescription of exercise for people with mental illness. Addressing the barriers to exercise prescription could improve the proportion of nurses who routinely prescribe exercise. Collaboration with exercise professionals, such as accredited exercise physiologists or physiotherapists, might improve knowledge of evidence-based exercise-prescription practices for people with mental illness, thereby improving both physical and mental health outcomes for this vulnerable population. © 2015 Australian College of Mental Health Nurses Inc.

Load Variation Influences on Joint Work During Squat Exercise in Reduced Gravity

NASA Technical Reports Server (NTRS)

DeWitt, John K.; Fincke, Renita S.; Logan, Rachel L.; Guilliams, Mark E.; Ploutz-Snyder, Lori L.

2011-01-01

Resistance exercises that load the axial skeleton, such as the parallel squat, are incorporated as a critical component of a space exercise program designed to maximize the stimuli for bone remodeling and muscle loading. Astronauts on the International Space Station perform regular resistance exercise using the Advanced Resistive Exercise Device (ARED). Squat exercises on Earth entail moving a portion of the body weight plus the added bar load, whereas in microgravity the body weight is 0, so all load must be applied via the bar. Crewmembers exercising in microgravity currently add approx.70% of their body weight to the bar load as compensation for the absence of the body weight. This level of body weight replacement (BWR) was determined by crewmember feedback and personal experience without any quantitative data. The purpose of this evaluation was to utilize computational simulation to determine the appropriate level of BWR in microgravity necessary to replicate lower extremity joint work during squat exercise in normal gravity based on joint work. We hypothesized that joint work would be positively related to BWR load.

The effect of acute aerobic and resistance exercise on working memory.

PubMed

Pontifex, Matthew B; Hillman, Charles H; Fernhall, Bo; Thompson, Kelli M; Valentini, Teresa A

2009-04-01

The goal of this investigation was to assess the influence of acute bouts of aerobic versus resistance exercise on the executive control of working memory. Twenty-one young adult participants completed a cardiorespiratory fitness test and maximal strength tests. On subsequent days, task performance measures of reaction time (RT) and accuracy were collected while participants completed a modified Sternberg working memory task before the start of, immediately after, and 30 min after an intervention consisting of 30 min of either resistance or aerobic exercise and a seated rest control. Findings indicated shorter RT immediately and 30 min after acute aerobic exercise relative to the preexercise baseline with no such effects observed after resistance exercise or seated rest. Further, in the aerobic condition, a larger reduction in RT from the baseline occurred during task conditions requiring increased working memory capacity. Again, no effect was observed in the resistance exercise or the seated rest conditions. These data extend the current knowledge base by indicating that acute exercise-induced changes in cognition are disproportionately related to executive control and may be specific to the aerobic exercise domain.

Prognostic capacity of a clinically indicated exercise test for cardiovascular mortality is enhanced by combined analysis of exercise capacity, heart rate recovery and T-wave alternans.

PubMed

Minkkinen, Mikko; Nieminen, Tuomo; Verrier, Richard L; Leino, Johanna; Lehtimäki, Terho; Viik, Jari; Lehtinen, Rami; Nikus, Kjell; Kööbi, Tiit; Turjanmaa, Väinö; Kähönen, Mika

2015-09-01

Exercise capacity, heart rate recovery and T-wave alternans are independent predictors of cardiovascular mortality. We tested whether these parameters contain supplementary prognostic information. A total of 3609 consecutive patients (2157 men) referred for a routine, clinically indicated bicycle exercise test were enrolled in the Finnish Cardiovascular Study (FINCAVAS). Exercise capacity was measured in metabolic equivalents, heart rate recovery as the decrease in heart rate from maximum to one minute post-exercise, and T-wave alternans by time-domain Modified Moving Average method. During 57-month median follow-up (interquartile range 35-78 months), 96 patients died of cardiovascular causes (primary endpoint) and 233 from any cause. All three parameters were independent predictors of cardiovascular mortality when analysed as continuous variables. Adding metabolic equivalents (p < 0.001), heart rate recovery (p = 0.002) or T-wave alternans (p = 0.01) to the linear model improved its predictive power for cardiovascular mortality. The combination of low exercise capacity (<6 metabolic equivalents), reduced heart rate recovery (≤12 beats/min) and elevated T-wave alternans (≥60 μV) yielded the highest hazard ratio for cardiovascular mortality of 16.5 (95% confidence interval 4.0-67.7, p < 0.001). Harrell's C index was 0.719 (confidence interval 0.665-0.772) for cardiovascular mortality with previously defined cutpoints (<8 units for metabolic equivalents, ≤18 beats/min for heart rate recovery and ≥60 μV for T-wave alternans). The prognostic capacity of the clinical exercise test is enhanced by combined analysis of exercise capacity, heart rate recovery and T-wave alternans. © The European Society of Cardiology 2014.

14 CFR 61.3 - Requirement for certificates, ratings, and authorizations.

Code of Federal Regulations, 2012 CFR

2012-01-01

... with a glider category rating, a balloon class rating, or glider or balloon privileges; (ii) Is... than glider or balloon privileges and holds a U.S. driver's license; (iii) Is exercising the privileges... exercising the privileges of a sport pilot certificate with glider or balloon privileges; (v) Is exercising...

14 CFR 61.3 - Requirement for certificates, ratings, and authorizations.

Code of Federal Regulations, 2013 CFR

2013-01-01

... with a glider category rating, a balloon class rating, or glider or balloon privileges; (ii) Is... than glider or balloon privileges and holds a U.S. driver's license; (iii) Is exercising the privileges... exercising the privileges of a sport pilot certificate with glider or balloon privileges; (v) Is exercising...

14 CFR 61.3 - Requirement for certificates, ratings, and authorizations.

Code of Federal Regulations, 2011 CFR

2011-01-01

... with a glider category rating, a balloon class rating, or glider or balloon privileges; (ii) Is... than glider or balloon privileges and holds a U.S. driver's license; (iii) Is exercising the privileges... exercising the privileges of a sport pilot certificate with glider or balloon privileges; (v) Is exercising...

Constant-load versus heart rate-targeted exercise - Responses of systolic intervals

NASA Technical Reports Server (NTRS)

Lance, V. Q.; Spodick, D. H.

1975-01-01

Various systolic intervals were measured prior to and during heart rate-targeted bicycle ergometer exercise. There were striking similarities within each matched exercise set for Q-Im, isovolumetric contraction time, preejection period (PEP), and PEP/left ventricular ejection time (LVET). LVET was significantly shorter for rate-targeted exercise. It is concluded that either constant-load or rate-targeted bicycle ergometry may be used with the choice of method determined by the purpose of the protocol, and that systolic intervals (except LVET) should not be much altered owing to the method chosen.

Impact of Age and Aerobic Exercise Training on Conduit Artery Wall Thickness: Role of the Shear Pattern.

PubMed

Tanahashi, Koichiro; Kosaki, Keisei; Sawano, Yuriko; Yoshikawa, Toru; Tagawa, Kaname; Kumagai, Hiroshi; Akazawa, Nobuhiko; Maeda, Seiji

2017-01-01

Hemodynamic shear stress is the frictional force of blood on the arterial wall. The shear pattern in the conduit artery affects the endothelium and may participate in the development and progression of atherosclerosis. We investigated the role of the shear pattern in age- and aerobic exercise-induced changes in conduit artery wall thickness via cross-sectional and interventional studies. In a cross-sectional study, we found that brachial shear rate patterns and brachial artery intima-media thickness (IMT) correlated with age. Additionally, brachial artery shear rate patterns were associated with brachial artery IMT in 102 middle-aged and older individuals. In an interventional study, 39 middle-aged and older subjects were divided into 2 groups: control and exercise. The exercise group completed 12 weeks of aerobic exercise training. Aerobic exercise training significantly increased the antegrade shear rate and decreased the retrograde shear rate and brachial artery IMT. Moreover, changes in the brachial artery antegrade shear rate and the retrograde shear rate correlated with the change in brachial artery IMT. The results of the present study indicate that changes in brachial artery shear rate patterns may contribute to age- and aerobic exercise training-induced changes in brachial artery wall thickness. © 2017 S. Karger AG, Basel.

Do 'mind over muscle' strategies work? Examining the effects of attentional association and dissociation on exertional, affective and physiological responses to exercise.

PubMed

Lind, Erik; Welch, Amy S; Ekkekakis, Panteleimon

2009-01-01

Despite the well established physical and psychological benefits derived from leading a physically active life, rates of sedentary behaviour remain high. Dropout and non-compliance are major contributors to the problem of physical inactivity. Perceptions of exertion, affective responses (e.g. displeasure or discomfort), and physiological stress could make the exercise experience aversive, particularly for beginners. Shifting one's attentional focus towards environmental stimuli (dissociation) instead of one's body (association) has been theorized to enhance psychological responses and attenuate physiological stress. Research evidence on the effectiveness of attentional focus strategies, however, has been perplexing, covering the entire gamut of possible outcomes (association and dissociation having been shown to be both effective and ineffective). This article examines the effects of manipulations of attentional focus on exertional and affective responses, as well as on exercise economy and tolerance. The possible roles of the characteristics of the exercise stimulus (intensity, duration) and the exercise participants, methodological issues, and limitations of experimental designs are discussed. In particular, the critical role of exercise intensity is emphasized. Dissociative strategies may be more effective in reducing perceptions of exertion and enhancing affective responses at low to moderate exercise intensities, but their effectiveness may be diminished at higher and near-maximal levels, at which physiological cues dominate. Conversely, associative strategies could enable the exerciser to regulate intensity to avoid injury or overexertion. Thus, depending on intensity, both strategies have a place in the 'toolbox' of the public health or exercise practitioner as methods of enhancing the exercise experience and promoting long-term compliance.

Cognitive function at rest and during exercise following breakfast omission.

PubMed

Komiyama, Takaaki; Sudo, Mizuki; Okuda, Naoki; Yasuno, Tetsuhiko; Kiyonaga, Akira; Tanaka, Hiroaki; Higaki, Yasuki; Ando, Soichi

2016-04-01

It has been suggested that breakfast omission, as opposed to breakfast consumption, has the detrimental effects on cognitive function. However, the effects of acute exercise following breakfast omission on cognitive function are poorly understood, particularly during exercise. The purpose of this study was to examine the interactive effects of breakfast and exercise on cognitive function. Ten participants completed cognitive tasks at rest and during exercise in the breakfast consumption or omission conditions. Blood glucose concentration was measured immediately after each cognitive task. We used cognitive tasks to assess working memory [Spatial Delayed Response (DR) task] and executive function [Go/No-Go (GNG) task]. The participants cycled ergometer for 30 min while keeping their heart rate at 140 beats·min(-1). Accuracy of the GNG task was lower at rest in the breakfast omission condition than that in the breakfast consumption condition (Go trial: P=0.012; No-Go trial: P=0.028). However, exercise improved accuracy of the Go trial in the breakfast omission condition (P=0.013). Reaction time in the Go trial decreased during exercise relative to rest in both conditions (P=0.002), and the degree of decreases in reaction time was not different between conditions (P=0.448). Exercise and breakfast did not affect the accuracy of the Spatial DR task. The present results indicate that breakfast omission impairs executive function, but acute exercise improved executive function even after breakfast omission. It appears that beneficial effects of acute exercise on cognitive function are intact following breakfast omission. Copyright © 2016 Elsevier Inc. All rights reserved.

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

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

Rhesus monkey heart rate during exercise

NASA Technical Reports Server (NTRS)

Delorge, J.; Thach, J. S., Jr.

1972-01-01

Various schedules of reinforcement and their relation to heart rates of rhesus monkeys during exercise are described. All the reinforcement schedules produced 100 per cent or higher increments in the heart rates of the monkeys during exercise. Resting heart rates were generally much lower than those previously reported, which was attributed to the lack of physical restraint of the monkeys during recording.

Software tools for interactive instruction in radiologic anatomy.

PubMed

Alvarez, Antonio; Gold, Garry E; Tobin, Brian; Desser, Terry S

2006-04-01

To promote active learning in an introductory Radiologic Anatomy course through the use of computer-based exercises. DICOM datasets from our hospital PACS system were transferred to a networked cluster of desktop computers in a medical school classroom. Medical students in the Radiologic Anatomy course were divided into four small groups and assigned to work on a clinical case for 45 minutes. The groups used iPACS viewer software, a free DICOM viewer, to view images and annotate anatomic structures. The classroom instructor monitored and displayed each group's work sequentially on the master screen by running SynchronEyes, a software tool for controlling PC desktops remotely. Students were able to execute the assigned tasks using the iPACS software with minimal oversight or instruction. Course instructors displayed each group's work on the main display screen of the classroom as the students presented the rationale for their decisions. The interactive component of the course received high ratings from the students and overall course ratings were higher than in prior years when the course was given solely in lecture format. DICOM viewing software is an excellent tool for enabling students to learn radiologic anatomy from real-life clinical datasets. Interactive exercises performed in groups can be powerful tools for stimulating students to learn radiologic anatomy.

Myocardial work during endurance training and resistance training: a daily comparison, from workout session 1 through completion of cardiac rehabilitation

PubMed Central

Hubbard, Matthew; McCullough-Shock, Tiffany; Simms, Kay; Cheng, Dunlei; Hartman, Julie; Strauss, Danielle; Anderson, Valerie; Lawrence, Anne; Malorzo, Emily

2010-01-01

Patients in cardiac rehabilitation are typically advised to complete a period of supervised endurance training before beginning resistance training. In this study, however, we compared the peak rate-pressure product (RPP, a calculated indicator of myocardial work) of patients during two types of exercise—treadmill walking and chest press—from workout session 1 through completion of cardiac rehabilitation. Twenty-one patients (4 women and 17 men, aged 35 to 70 years) were enrolled in the study; they were referred for cardiac rehabilitation after myocardial infarction, percutaneous coronary intervention, or both. The participants did treadmill walking and chest press exercises during each workout session. Peak values for heart rate (HR) and systolic blood pressure (SBP) were recorded, and the peak RPP was calculated (peak HR ⊠ peak SBP). Paired t tests were used to compare the data collected during the two types of exercise across 19 workout sessions. The mean peak values for HR, SBP, and RPP were lower during resistance training than during endurance training; the differences were statistically significant (P < 0.05), with only one exception (the SBP for session 1). Across all 19 workout sessions, the participants performed more myocardial work, as indicated by the peak RPP, during treadmill walking than during the chest press. PMID:20396420

Comparison between Nintendo Wii Fit aerobics and traditional aerobic exercise in sedentary young adults.

PubMed

Douris, Peter C; McDonald, Brittany; Vespi, Frank; Kelley, Nancy C; Herman, Lawrence

2012-04-01

Exergaming is becoming a popular recreational activity for young adults. The purpose was to compare the physiologic and psychological responses of college students playing Nintendo Wii Fit, an active video game console, vs. an equal duration of moderate-intensity brisk walking. Twenty-one healthy sedentary college-age students (mean age 23.2 ± 1.8 years) participated in a randomized, double cross-over study, which compared physiologic and psychological responses to 30 minutes of brisk walking exercise on a treadmill vs. 30 minutes playing Nintendo Wii Fit "Free Run" program. Physiologic parameters measured included heart rate, rate pressure product, respiratory rate, and rating of perceived exertion. Participants' positive well-being, psychological distress, and level of fatigue associated with each exercise modality were quantified using the Subjective Exercise Experience Scale. The mean maximum heart rate (HRmax) achieved when exercising with Wii Fit (142.4 ± 20.5 b·min(-1)) was significantly greater (p = 0.001) compared with exercising on the treadmill (123.2 ± 13.7 b·min(-1)). Rate pressure product was also significantly greater (p = 0.001) during exercise on the Wii Fit. Participants' rating of perceived exertion when playing Wii Fit (12.7 ± 3.0) was significantly greater (p = 0.014) when compared with brisk walking on the treadmill (10.1 ± 3.3). However, psychologically when playing Wii Fit, participants' positive well-being decreased significantly (p = 0.018) from preexercise to postexercise when compared with exercising on the treadmill. College students have the potential to surpass exercise intensities achieved when performing a conventional standard for moderate-intensity exercise when playing Nintendo Wii Fit "Free Run" with a self-selected intensity. We concluded that Nintendo Wii Fit "Free Run" may act as an alternative to traditional moderate-intensity aerobic exercise in fulfilling the American College of Sports Medicine requirements for physical activity.

The Relation of Arm Exercise Peak Heart Rate to Stress Test Results and Outcome.

PubMed

Xian, Hong; Liu, Weijian; Marshall, Cynthia; Chandiramani, Pooja; Bainter, Emily; Martin, Wade H

2016-09-01

Arm exercise is an alternative to pharmacologic stress testing for >50% of patients unable to perform treadmill exercise, but no data exist regarding the effect of attained peak arm exercise heart rate on test sensitivity. Thus, the purpose of this investigation was to characterize the relationship of peak arm exercise heart rate responses to abnormal stress test findings, coronary revascularization, and mortality in patients unable to perform leg exercise. From 1997 until 2002, arm cycle ergometer stress tests were performed in 443 consecutive veterans age 64.1 yr (11.0 yr) (mean (SD)), of whom 253 also underwent myocardial perfusion imaging (MPI). Patients were categorized by frequency distributions of quartiles of percentage age-predicted peak heart rate (APPHR), heart rate reserve (HRR), and peak heart rate-systolic blood pressure product (PRPP). Exercise-induced ST-segment depression, abnormal MPI findings, coronary revascularization, and 12.0-yr (1.3 yr) Kaplan-Meier all-cause and cardiovascular mortality plots were then characterized by quartiles of APPHR, HRR, and PRPP. A reduced frequency of abnormal arm exercise ECG results was associated only with the lowest quartile of APPHR (≤69%) and HRR (≤43%), whereas higher frequency of abnormal MPI findings exhibited an inverse relationship trend with lower APPHR (P = 0.10) and HRR (P = 0.12). There was a strong inverse association of APPHR, HRR, and PRPP with all-cause (all P ≤ 0.01) and cardiovascular (P < 0.05) mortality. The frequency of coronary revascularization was unrelated to APPHR or HRR. Arm exercise ECG stress test sensitivity is only reduced at ≤69% APPHR or ≤43% HRR, whereas arm exercise MPI sensitivity and referral for coronary revascularization after arm exercise stress testing are not adversely affected by even a severely blunted peak heart rate. However, both all-cause mortality and cardiovascular mortality are strongly and inversely related to APPHR and HRR.

Effects of Endurance and Endurance Strength Training on Body Composition and Physical Capacity in Women with Abdominal Obesity.

PubMed

Skrypnik, Damian; Bogdański, Paweł; Mądry, Edyta; Karolkiewicz, Joanna; Ratajczak, Marzena; Kryściak, Jakub; Pupek-Musialik, Danuta; Walkowiak, Jarosław

2015-01-01

To compare the effects of endurance training with endurance strength training on the anthropometric, body composition, physical capacity, and circulatory parameters in obese women. 44 women with abdominal obesity were randomized into groups A and B, and asked to perform endurance (A) and endurance strength training (B) for 3 months, 3 times/week, for 60 min. Dual-energy X-ray absorptiometry and Graded Exercise Test were performed before and after training. Significant decreases in body mass, BMI, total body fat, total body fat mass, and waist and hip circumference were observed after both types of intervention. Marked increases in total body lean and total body fat-free mass were documented in group B. In both groups, significant increases in peak oxygen uptake, time to exhaustion, maximal work rate, and work rate at ventilatory threshold were accompanied by noticeably decreased resting heart rate, resting systolic blood pressure, and resting and exercise diastolic blood pressure. No significant differences were noticed between groups for the investigated parameters. Our findings demonstrate evidence for a favorable and comparable effect of 3-month endurance and endurance strength training on anthropometric parameters, body composition, physical capacity, and circulatory system function in women with abdominal obesity. © 2015 S. Karger GmbH, Freiburg.

Effects of Endurance and Endurance Strength Training on Body Composition and Physical Capacity in Women with Abdominal Obesity

PubMed Central

Skrypnik, Damian; Bogdański, Paweł; Mądry, Edyta; Karolkiewicz, Joanna; Ratajczak, Marzena; Kryściak, Jakub; Pupek-Musialik, Danuta; Walkowiak, Jarosław

2015-01-01

Aims To compare the effects of endurance training with endurance strength training on the anthropometric, body composition, physical capacity, and circulatory parameters in obese women. Methods 44 women with abdominal obesity were randomized into groups A and B, and asked to perform endurance (A) and endurance strength training (B) for 3 months, 3 times/week, for 60 min. Dual-energy X-ray absorptiometry and Graded Exercise Test were performed before and after training. Results Significant decreases in body mass, BMI, total body fat, total body fat mass, and waist and hip circumference were observed after both types of intervention. Marked increases in total body lean and total body fat-free mass were documented in group B. In both groups, significant increases in peak oxygen uptake, time to exhaustion, maximal work rate, and work rate at ventilatory threshold were accompanied by noticeably decreased resting heart rate, resting systolic blood pressure, and resting and exercise diastolic blood pressure. No significant differences were noticed between groups for the investigated parameters. Conclusion Our findings demonstrate evidence for a favorable and comparable effect of 3-month endurance and endurance strength training on anthropometric parameters, body composition, physical capacity, and circulatory system function in women with abdominal obesity. PMID:25968470

Individual preferences for physical exercise as secondary prevention for non-specific low back pain: A discrete choice experiment

PubMed Central

Hagberg, Jan; Axén, Iben; Kwak, Lydia; Lohela-Karlsson, Malin; Skillgate, Eva; Dahlgren, Gunilla; Jensen, Irene

2017-01-01

Background Exercise is effective in improving non-specific low back pain (LBP). Certain components of physical exercise, such as the type, intensity and frequency of exercise, are likely to influence participation among working adults with non-specific LBP, but the value and relative importance of these components remain unknown. The study’s aim was to examine such specific components and their influence on individual preferences for exercise for secondary prevention of non-specific LBP among working adults. Methods In a discrete choice experiment, working individuals with non-specific LBP answered a web-based questionnaire. Each respondent was given ten pairs of hypothetical exercise programs and asked to choose one option from each pair. The choices comprised six attributes of exercise (i.e., type of training, design, intensity, frequency, proximity and incentives), each with either three or four levels. A conditional logit regression that reflected the random utility model was used to analyze the responses. Results The final study population consisted of 112 participants. The participants’ preferred exercise option was aerobic (i.e., cardiovascular) rather than strength training, group exercise with trainer supervision, rather than individual or unsupervised exercise. They also preferred high intensity exercise performed at least once or twice per week. The most popular types of incentive were exercise during working hours and a wellness allowance rather than coupons for sports goods. The results show that the relative value of some attribute levels differed between young adults (age ≤ 44 years) and older adults (age ≥ 45 years) in terms of the level of trainer supervision required, exercise intensity, travel time to exercise location and financial incentives. For active study participants, exercise frequency (i.e., twice per week, 1.15; CI: 0.25; 2.06) influenced choice of exercise. For individuals with more than one child, travel time (i.e., 20 minutes, -0.55; CI: 0.65; 3.26) was also an influential attribute for choice of exercise, showing that people with children at home preferred to exercise close to home. Conclusions This study adds to our knowledge about what types of exercise working adults with back pain are most likely to participate in. The exercise should be a cardiovascular type of training carried out in a group with trainer supervision. It should also be of high intensity and preferably performed twice per week during working hours. Coupons for sports goods do not appear to motivate physical activity among workers with LBP. The findings of the study could have a substantial impact on the planning and development of exercise provision and promotion strategies to improve non-specific LBP. Providers and employers may be able to improve participation in exercise programs for adults with non-specific LBP by focusing on the exercise components which are the most attractive. This in turn would improve satisfaction and adherence to exercise interventions aimed at preventing recurrent non-specific LBP. PMID:29244841

Individual preferences for physical exercise as secondary prevention for non-specific low back pain: A discrete choice experiment.

PubMed

Aboagye, Emmanuel; Hagberg, Jan; Axén, Iben; Kwak, Lydia; Lohela-Karlsson, Malin; Skillgate, Eva; Dahlgren, Gunilla; Jensen, Irene

2017-01-01

Exercise is effective in improving non-specific low back pain (LBP). Certain components of physical exercise, such as the type, intensity and frequency of exercise, are likely to influence participation among working adults with non-specific LBP, but the value and relative importance of these components remain unknown. The study's aim was to examine such specific components and their influence on individual preferences for exercise for secondary prevention of non-specific LBP among working adults. In a discrete choice experiment, working individuals with non-specific LBP answered a web-based questionnaire. Each respondent was given ten pairs of hypothetical exercise programs and asked to choose one option from each pair. The choices comprised six attributes of exercise (i.e., type of training, design, intensity, frequency, proximity and incentives), each with either three or four levels. A conditional logit regression that reflected the random utility model was used to analyze the responses. The final study population consisted of 112 participants. The participants' preferred exercise option was aerobic (i.e., cardiovascular) rather than strength training, group exercise with trainer supervision, rather than individual or unsupervised exercise. They also preferred high intensity exercise performed at least once or twice per week. The most popular types of incentive were exercise during working hours and a wellness allowance rather than coupons for sports goods. The results show that the relative value of some attribute levels differed between young adults (age ≤ 44 years) and older adults (age ≥ 45 years) in terms of the level of trainer supervision required, exercise intensity, travel time to exercise location and financial incentives. For active study participants, exercise frequency (i.e., twice per week, 1.15; CI: 0.25; 2.06) influenced choice of exercise. For individuals with more than one child, travel time (i.e., 20 minutes, -0.55; CI: 0.65; 3.26) was also an influential attribute for choice of exercise, showing that people with children at home preferred to exercise close to home. This study adds to our knowledge about what types of exercise working adults with back pain are most likely to participate in. The exercise should be a cardiovascular type of training carried out in a group with trainer supervision. It should also be of high intensity and preferably performed twice per week during working hours. Coupons for sports goods do not appear to motivate physical activity among workers with LBP. The findings of the study could have a substantial impact on the planning and development of exercise provision and promotion strategies to improve non-specific LBP. Providers and employers may be able to improve participation in exercise programs for adults with non-specific LBP by focusing on the exercise components which are the most attractive. This in turn would improve satisfaction and adherence to exercise interventions aimed at preventing recurrent non-specific LBP.

Control group design, contamination and drop-out in exercise oncology trials: a systematic review.

PubMed

Steins Bisschop, Charlotte N; Courneya, Kerry S; Velthuis, Miranda J; Monninkhof, Evelyn M; Jones, Lee W; Friedenreich, Christine; van der Wall, Elsken; Peeters, Petra H M; May, Anne M

2015-01-01

Important considerations for exercise trials in cancer patients are contamination and differential drop-out among the control group members that might jeopardize the internal validity. This systematic review provides an overview of different control groups design characteristics of exercise-oncology trials and explores the association with contamination and drop-out rates. Randomized controlled exercise-oncology trials from two Cochrane reviews were included. Additionally, a computer-aided search using Medline (Pubmed), Embase and CINAHL was conducted after completion date of the Cochrane reviews. Eligible studies were classified according to three control group design characteristics: the exercise instruction given to controls before start of the study (exercise allowed or not); and the intervention the control group was offered during (any (e.g., education sessions or telephone contacts) or none) or after (any (e.g., cross-over or exercise instruction) or none) the intervention period. Contamination (yes or no) and excess drop-out rates (i.e., drop-out rate of the control group minus the drop-out rate exercise group) were described according to the three design characteristics of the control group and according to the combinations of these three characteristics; so we additionally made subgroups based on combinations of type and timing of instructions received. 40 exercise-oncology trials were included based on pre-specified eligibility criteria. The lowest contamination (7.1% of studies) and low drop-out rates (excess drop-out rate -4.7±9.2) were found in control groups offered an intervention after the intervention period. When control groups were offered an intervention both during and after the intervention period, contamination (0%) and excess drop-out rates (-10.0±12.8%) were even lower. Control groups receiving an intervention during and after the study intervention period have lower contamination and drop-out rates. The present findings can be considered when designing future exercise-oncology trials.

[Using Interdisciplinary Cooperation to Improve the Rate of Proper Performance of a Hand Exercise Among Hemodialysis Patients With Arteriovenous Fistula Construction].

PubMed

Hsiao, Ya-Hsin; Shin, Miao-Ling; Huang, Cyong-Pei; Chen, Siang-Jyun; Huang, Tsuey-Yuan

2017-06-01

Patients who undergo new arteriovenous fistula (AVF) construction as part of their hemodialysis treatment program are required to perform hand exercises properly in order to maintain AVF function. However, poor performance of these hand exercises currently results in the failure of many patients to preserve AVF function. To increase the rate of performing this hand exercise properly from 55% to 80%. A comprehensive investigation identified the following five main problems: (a) Insufficient muscular endurance; (b) Resistance was not labeled on the ball; (c) Difficulties with maintaining a grip on the ball during the exercise; (d) Lack of standardized education procedures; and (e) Nurses lack latest knowledge on the hand exercise. The strategies used to improve the situation included: (a) Interdisciplinary team cooperation with physiotherapists to design individualized resistance training regimens; (b) Exercise tool improvement; (c) Standardized AVF care; (d) Continuous education for nursing staffs; and (e) Seed teacher program for hand exercise. The rate of proper hand exercise performance increased from 55% to 93%. This nursing project involved an interdisciplinary team that included physiotherapists in order to successfully improve the rate at which the hand exercise was performed properly. This positive experience may be applied to other hemodialysis departments in the treatment of patients with AVF.

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

PubMed

Wang, Xiao-Qin; Wang, Gong-Wu

2016-03-15

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

Effect of set configuration on hemodynamics and cardiac autonomic modulation after high-intensity squat exercise.

PubMed

Iglesias-Soler, Eliseo; Boullosa, Daniel A; Carballeira, Eduardo; Sánchez-Otero, Tania; Mayo, Xian; Castro-Gacio, Xabier; Dopico, Xurxo

2015-07-01

The aim of this study was to compare the effect of two different high-intensity resistance exercise (RE) set configurations on the following: systolic blood pressure (SBP), rate pressure product (RPP), heart rate (HR) variability (HRV), and HR complexity (HRC). Ten well-trained males performed three parallel squat sets until failure (traditional training; TT) with the four repetitions maximum load (4RM), and a rest of 3 min between sets. Thereafter, participants performed a cluster training session (CT) of equated load but with resting time distributed between each repetition. Dependent variables were recorded before, during, and after RE. Mean SBP (25·7 versus 10·9% percentage increase; P = 0·016) and RPP (112·5 versus 69·9%; P = 0·01) were significantly higher in TT. The decrease in HRV after exercise and the drop of HRC during exercise were similar in CT and TT. Change of standard deviation of normal RR intervals after TT correlated with change in SBP (r = 0·803; P = 0·009) while the change of Sample Entropy during exercise correlated with the increment of RPP during CT (ρ = -0·667; P = 0·05). This study suggests that set configuration influences acute cardiovascular responses during RE. When intensity, volume and work-to-rest ratio are equated, CT is less demanding in terms of SBP and RPP. A greater hemodynamic response during exercise would be associated with a faster parasympathetic recovery. © 2014 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

Physiological effects of hydrogen sulfide inhalation during exercise in healthy men.

PubMed

Bhambhani, Y; Singh, M

1991-11-01

Occupational exposure to hydrogen sulfide (H2S) is prevalent in a variety of industries. H2S when inhaled 1) is oxidized into a sulfate or a thiosulfate by oxygen bound to hemoglobin and 2) suppresses aerobic metabolism by inhibiting cytochrome oxidase (c and aa3) activity in the electron transport chain. The purpose of this study was to examine the acute effects of oral inhalation of H2S on the physiological responses during graded cycle exercise performed to exhaustion in healthy male subjects. Sixteen volunteers were randomly exposed to 0 (control), 0.5, 2.0, and 5.0 ppm H2S on four separate occasions. Compared with the control values, the results indicated that the heart rate and expired ventilation were unaffected as a result of the H2S exposures during submaximal and maximal exercise. The oxygen uptake had a tendency to increase, whereas carbon dioxide output had a tendency to decrease as a result of the H2S exposures, but only the 5.0 ppm exposure resulted in a significantly higher maximum oxygen uptake. Blood lactate concentrations increased significantly during submaximal and maximal exercise as a result of the 5.0 ppm exposure. Despite these large increases in lactate concentration, the maximal power output of the subjects was not significantly altered as a result of the 5.0 ppm H2S exposure. It was concluded that healthy young male subjects could safely exercise at their maximum metabolic rates while breathing 5.0 ppm H2S without experiencing a significant reduction in their maximum physical work capacity during short-term incremental exercise.

Work capacity and oxygen uptake abnormalities in hyperthyroidism.

PubMed

Irace, L; Pergola, V; Di Salvo, G; Perna, B; Tedesco, M A; Ricci, C; Tuccillo, B; Iacono, A

2006-06-01

The aim of our study was to evaluate the haemodynamic and the respiratory response to exercise in patients with hyperthyroidism before and 30 days after normalized thyroid hormones levels. These findings were compared with those of 10 control patients. Thirty patients (23 women, aged 34.3 +/- 12 years) with untreated hyperthyroidism were studied. Twenty-four patients were treated with methimazole, 13 of which were also treated with propranolol. Six patients underwent surgery. A symptom-limited cardiopulmonary exercise test and an echocardiography were performed in all patients. At rest patients with hyperthyroidism showed at echocardiography an increased cardiac index (P = 0.006 vs euthyroid, P = 0.007 vs normal) and a higher ejection fraction (P = 0.008 vs euthyroid, P = 0.007 vs normal). The duration of the exercise was lower in hyperthyroid patients (P = 0.006 vs euthyroid; P = 0.0068 vs normal). Anaerobic threshold was reached at 49.6% of peak VO2 during hyperthyroidism, at 60.8% during euthyroidism (P = 0.01) and at 62% in normal (P = 0.01). Work rate was lower in patients with hyperthyroidism at anaerobic threshold (P = 0.01 vs euthyroid, P = 0.03 vs normal) and at maximal work (P = 0.001 vs euthyroid, P = 0.01 vs normal). Patients in hyperthyroidism showed a lower increment of heart rate between rest and anaerobic threshold (P = 0.021 vs euthyroid, P < 0.0001 vs normal) and a lower VO2 at anaerobic threshold (P = 0.03 vs euthyroid; P = 0.04 vs normal). Oxygen pulse at anaerobic threshold was significantly reduced in hyperthyroidism (P = 0.04 vs euthyroid, P = 0.005 vs normal). The mean result is that after only 30 days of appropriate antithyroid treatment there was an appreciable improvement of exertion capacity.

Music Attenuated a Decrease in Parasympathetic Nervous System Activity after Exercise.

PubMed

Jia, Tiantian; Ogawa, Yoshiko; Miura, Misa; Ito, Osamu; Kohzuki, Masahiro

2016-01-01

Music and exercise can both affect autonomic nervous system activity. However, the effects of the combination of music and exercise on autonomic activity are poorly understood. Additionally, it remains unknown whether music affects post-exercise orthostatic tolerance. The aim of this study was to evaluate the effects of music on autonomic nervous system activity in orthostatic tolerance after exercise. Twenty-six healthy graduate students participated in four sessions in a random order on four separate days: a sedentary session, a music session, a bicycling session, and a bicycling with music session. Participants were asked to listen to their favorite music and to exercise on a cycle ergometer. We evaluated autonomic nervous system activity before and after each session using frequency analysis of heart rate variability. High frequency power, an index of parasympathetic nervous system activity, was significantly increased in the music session. Heart rate was increased, and high frequency power was decreased, in the bicycling session. There was no significant difference in high frequency power before and after the bicycling with music session, although heart rate was significantly increased. Additionally, both music and exercise did not significantly affect heart rate, systolic blood pressure or also heart rate variability indices in the orthostatic test. These data suggest that music increased parasympathetic activity and attenuated the exercise-induced decrease in parasympathetic activity without altering the orthostatic tolerance after exercise. Therefore, music may be an effective approach for improving post-exercise parasympathetic reactivation, resulting in a faster recovery and a reduction in cardiac stress after exercise.

Efficacy of exercise therapy in workers with rotator cuff tendinopathy: a systematic review

PubMed Central

Desmeules, François; Boudreault, Jennifer; Dionne, Clermont E.; Frémont, Pierre; Lowry, Véronique; MacDermid, Joy C.; Roy, Jean-Sébastien

2016-01-01

Objective: To perform a systematic review of randomized controlled trials (RCTs) on the efficacy of therapeutic exercises for workers suffering from rotator cuff (RC) tendinopathy. Methods: A literature search in four bibliographical databases (Pubmed, CINAHL, EMBASE, and PEDro) was conducted from inception up to February 2015. RCTs were included if participants were workers suffering from RC tendinopathy, the outcome measures included work-related outcomes, and at least one of the interventions under study included exercises. The methodological quality of the studies was evaluated with the Cochrane Risk of Bias Assessment tool. Results: The mean methodological score of the ten included studies was 54.4%±17.2%. Types of workers included were often not defined, and work-related outcome measures were heterogeneous and often not validated. Three RCTs of moderate methodological quality concluded that exercises were superior to a placebo or no intervention in terms of function and return-to-work outcomes. No significant difference was found between surgery and exercises based on the results of two studies of low to moderate methodological quality. One study of low methodological quality, comparing a workplace-based exercise program focusing on the participants' work demands to an exercise program delivered in a clinical setting, concluded that the work-based intervention was superior in terms of function and return-to-work outcomes. Conclusion: There is low to moderate-grade evidence that therapeutic exercises provided in a clinical setting are an effective modality to treat workers suffering from RC tendinopathy and to promote return-to-work. Further high quality studies comparing different rehabilitation programs including exercises in different settings with defined workers populations are needed to draw firm conclusions on the optimal program to treat workers. PMID:27488037

Efficacy of exercise therapy in workers with rotator cuff tendinopathy: a systematic review.

PubMed

Desmeules, François; Boudreault, Jennifer; Dionne, Clermont E; Frémont, Pierre; Lowry, Véronique; MacDermid, Joy C; Roy, Jean-Sébastien

2016-09-30

To perform a systematic review of randomized controlled trials (RCTs) on the efficacy of therapeutic exercises for workers suffering from rotator cuff (RC) tendinopathy. A literature search in four bibliographical databases (Pubmed, CINAHL, EMBASE, and PEDro) was conducted from inception up to February 2015. RCTs were included if participants were workers suffering from RC tendinopathy, the outcome measures included work-related outcomes, and at least one of the interventions under study included exercises. The methodological quality of the studies was evaluated with the Cochrane Risk of Bias Assessment tool. The mean methodological score of the ten included studies was 54.4%±17.2%. Types of workers included were often not defined, and work-related outcome measures were heterogeneous and often not validated. Three RCTs of moderate methodological quality concluded that exercises were superior to a placebo or no intervention in terms of function and return-to-work outcomes. No significant difference was found between surgery and exercises based on the results of two studies of low to moderate methodological quality. One study of low methodological quality, comparing a workplace-based exercise program focusing on the participants' work demands to an exercise program delivered in a clinical setting, concluded that the work-based intervention was superior in terms of function and return-to-work outcomes. There is low to moderate-grade evidence that therapeutic exercises provided in a clinical setting are an effective modality to treat workers suffering from RC tendinopathy and to promote return-to-work. Further high quality studies comparing different rehabilitation programs including exercises in different settings with defined workers populations are needed to draw firm conclusions on the optimal program to treat workers.

The Effects of Exercise Intensity vs. Metabolic State on the Variability and Magnitude of Left Ventricular Twist Mechanics during Exercise

PubMed Central

Armstrong, Craig; Samuel, Jake; Yarlett, Andrew; Cooper, Stephen-Mark; Stembridge, Mike; Stöhr, Eric J.

2016-01-01

Increased left ventricular (LV) twist and untwisting rate (LV twist mechanics) are essential responses of the heart to exercise. However, previously a large variability in LV twist mechanics during exercise has been observed, which complicates the interpretation of results. This study aimed to determine some of the physiological sources of variability in LV twist mechanics during exercise. Sixteen healthy males (age: 22 ± 4 years, V˙O2peak: 45.5 ± 6.9 ml∙kg-1∙min-1, range of individual anaerobic threshold (IAT): 32–69% of V˙O2peak) were assessed at rest and during exercise at: i) the same relative exercise intensity, 40%peak, ii) at 2% above IAT, and, iii) at 40%peak with hypoxia (40%peak+HYP). LV volumes were not significantly different between exercise conditions (P > 0.05). However, the mean margin of error of LV twist was significantly lower (F2,47 = 2.08, P < 0.05) during 40%peak compared with IAT (3.0 vs. 4.1 degrees). Despite the same workload and similar LV volumes, hypoxia increased LV twist and untwisting rate (P < 0.05), but the mean margin of error remained similar to that during 40%peak (3.2 degrees, P > 0.05). Overall, LV twist mechanics were linearly related to rate pressure product. During exercise, the intra-individual variability of LV twist mechanics is smaller at the same relative exercise intensity compared with IAT. However, the absolute magnitude (degrees) of LV twist mechanics appears to be associated with the prevailing rate pressure product. Exercise tests that evaluate LV twist mechanics should be standardised by relative exercise intensity and rate pressure product be taken into account when interpreting results. PMID:27100099

The Effects of Exercise Intensity vs. Metabolic State on the Variability and Magnitude of Left Ventricular Twist Mechanics during Exercise.

PubMed

Armstrong, Craig; Samuel, Jake; Yarlett, Andrew; Cooper, Stephen-Mark; Stembridge, Mike; Stöhr, Eric J

2016-01-01

Increased left ventricular (LV) twist and untwisting rate (LV twist mechanics) are essential responses of the heart to exercise. However, previously a large variability in LV twist mechanics during exercise has been observed, which complicates the interpretation of results. This study aimed to determine some of the physiological sources of variability in LV twist mechanics during exercise. Sixteen healthy males (age: 22 ± 4 years, [Formula: see text]O2peak: 45.5 ± 6.9 ml∙kg-1∙min-1, range of individual anaerobic threshold (IAT): 32-69% of [Formula: see text]O2peak) were assessed at rest and during exercise at: i) the same relative exercise intensity, 40%peak, ii) at 2% above IAT, and, iii) at 40%peak with hypoxia (40%peak+HYP). LV volumes were not significantly different between exercise conditions (P > 0.05). However, the mean margin of error of LV twist was significantly lower (F2,47 = 2.08, P < 0.05) during 40%peak compared with IAT (3.0 vs. 4.1 degrees). Despite the same workload and similar LV volumes, hypoxia increased LV twist and untwisting rate (P < 0.05), but the mean margin of error remained similar to that during 40%peak (3.2 degrees, P > 0.05). Overall, LV twist mechanics were linearly related to rate pressure product. During exercise, the intra-individual variability of LV twist mechanics is smaller at the same relative exercise intensity compared with IAT. However, the absolute magnitude (degrees) of LV twist mechanics appears to be associated with the prevailing rate pressure product. Exercise tests that evaluate LV twist mechanics should be standardised by relative exercise intensity and rate pressure product be taken into account when interpreting results.

Human Cardiac 31P-MR Spectroscopy at 3 Tesla Cannot Detect Failing Myocardial Energy Homeostasis during Exercise.

PubMed

Bakermans, Adrianus J; Bazil, Jason N; Nederveen, Aart J; Strijkers, Gustav J; Boekholdt, S Matthijs; Beard, Daniel A; Jeneson, Jeroen A L

2017-01-01

Phosphorus-31 magnetic resonance spectroscopy ( 31 P-MRS) is a unique non-invasive imaging modality for probing in vivo high-energy phosphate metabolism in the human heart. We investigated whether current 31 P-MRS methodology would allow for clinical applications to detect exercise-induced changes in (patho-)physiological myocardial energy metabolism. Hereto, measurement variability and repeatability of three commonly used localized 31 P-MRS methods [3D image-selected in vivo spectroscopy (ISIS) and 1D ISIS with 1D chemical shift imaging (CSI) oriented either perpendicular or parallel to the surface coil] to quantify the myocardial phosphocreatine (PCr) to adenosine triphosphate (ATP) ratio in healthy humans ( n = 8) at rest were determined on a clinical 3 Tesla MR system. Numerical simulations of myocardial energy homeostasis in response to increased cardiac work rates were performed using a biophysical model of myocardial oxidative metabolism. Hypertrophic cardiomyopathy was modeled by either inefficient sarcomere ATP utilization or decreased mitochondrial ATP synthesis. The effect of creatine depletion on myocardial energy homeostasis was explored for both conditions. The mean in vivo myocardial PCr/ATP ratio measured with 3D ISIS was 1.57 ± 0.17 with a large repeatability coefficient of 40.4%. For 1D CSI in a 1D ISIS-selected slice perpendicular to the surface coil, the PCr/ATP ratio was 2.78 ± 0.50 (repeatability 42.5%). With 1D CSI in a 1D ISIS-selected slice parallel to the surface coil, the PCr/ATP ratio was 1.70 ± 0.56 (repeatability 43.7%). The model predicted a PCr/ATP ratio reduction of only 10% at the maximal cardiac work rate in normal myocardium. Hypertrophic cardiomyopathy led to lower PCr/ATP ratios for high cardiac work rates, which was exacerbated by creatine depletion. Simulations illustrated that when conducting cardiac 31 P-MRS exercise stress testing with large measurement error margins, results obtained under pathophysiologic conditions may still lie well within the 95% confidence interval of normal myocardial PCr/ATP dynamics. Current measurement precision of localized 31 P-MRS for quantification of the myocardial PCr/ATP ratio precludes the detection of the changes predicted by computational modeling. This hampers clinical employment of 31 P-MRS for diagnostic testing and risk stratification, and warrants developments in cardiac 31 P-MRS exercise stress testing methodology.

Human Cardiac 31P-MR Spectroscopy at 3 Tesla Cannot Detect Failing Myocardial Energy Homeostasis during Exercise

PubMed Central

Bakermans, Adrianus J.; Bazil, Jason N.; Nederveen, Aart J.; Strijkers, Gustav J.; Boekholdt, S. Matthijs; Beard, Daniel A.; Jeneson, Jeroen A. L.

2017-01-01

Phosphorus-31 magnetic resonance spectroscopy (31P-MRS) is a unique non-invasive imaging modality for probing in vivo high-energy phosphate metabolism in the human heart. We investigated whether current 31P-MRS methodology would allow for clinical applications to detect exercise-induced changes in (patho-)physiological myocardial energy metabolism. Hereto, measurement variability and repeatability of three commonly used localized 31P-MRS methods [3D image-selected in vivo spectroscopy (ISIS) and 1D ISIS with 1D chemical shift imaging (CSI) oriented either perpendicular or parallel to the surface coil] to quantify the myocardial phosphocreatine (PCr) to adenosine triphosphate (ATP) ratio in healthy humans (n = 8) at rest were determined on a clinical 3 Tesla MR system. Numerical simulations of myocardial energy homeostasis in response to increased cardiac work rates were performed using a biophysical model of myocardial oxidative metabolism. Hypertrophic cardiomyopathy was modeled by either inefficient sarcomere ATP utilization or decreased mitochondrial ATP synthesis. The effect of creatine depletion on myocardial energy homeostasis was explored for both conditions. The mean in vivo myocardial PCr/ATP ratio measured with 3D ISIS was 1.57 ± 0.17 with a large repeatability coefficient of 40.4%. For 1D CSI in a 1D ISIS-selected slice perpendicular to the surface coil, the PCr/ATP ratio was 2.78 ± 0.50 (repeatability 42.5%). With 1D CSI in a 1D ISIS-selected slice parallel to the surface coil, the PCr/ATP ratio was 1.70 ± 0.56 (repeatability 43.7%). The model predicted a PCr/ATP ratio reduction of only 10% at the maximal cardiac work rate in normal myocardium. Hypertrophic cardiomyopathy led to lower PCr/ATP ratios for high cardiac work rates, which was exacerbated by creatine depletion. Simulations illustrated that when conducting cardiac 31P-MRS exercise stress testing with large measurement error margins, results obtained under pathophysiologic conditions may still lie well within the 95% confidence interval of normal myocardial PCr/ATP dynamics. Current measurement precision of localized 31P-MRS for quantification of the myocardial PCr/ATP ratio precludes the detection of the changes predicted by computational modeling. This hampers clinical employment of 31P-MRS for diagnostic testing and risk stratification, and warrants developments in cardiac 31P-MRS exercise stress testing methodology. PMID:29230178

Effects of Pilates Exercise on Salivary Secretory Immunoglobulin A Levels in Older Women.

PubMed

Hwang, Yoonyoung; Park, Jonghoon; Lim, Kiwon

2016-07-01

We examined the effects of a Pilates exercise program on the mucosal immune function in older women. The study population comprised 12 older women who were divided into a Pilates group (PG, n = 6) and a control group (CG, n = 6). Saliva samples were obtained from both groups before and after the experimental period for salivary secretory immunoglobulin A level measurement. In addition, acute high-intensity exercises were performed before and after the three-month Pilates exercise program. After three months, salivary flow was significantly higher in the PG than in the CG. After the acute high-intensity exercises were performed following the three-month Pilates exercise program, the salivary flow rate was significantly higher at all time points. The S-IgA secretion rate significantly increased 30 min after acute high-intensity exercise performed following the three-month Pilates exercise program. This study suggests that regular participation in a moderate-intensity Pilates exercise program can increase salivary flow rate and S-IgA secretion in older women.

Possible Link between Medical Students' Motivation for Academic Work and Time Engaged in Physical Exercise

ERIC Educational Resources Information Center

Aung, Myo Nyein; Somboonwong, Juraiporn; Jaroonvanichkul, Vorapol; Wannakrairot, Pongsak

2016-01-01

Physical exercise results in an active well-being. It is likely that students' engagement in physical exercise keeps them motivated to perform academic endeavors. This study aimed to assess the relation of time engaged in physical exercise with medical students' motivation for academic work. Prospectively, 296 second-year medical students…

Importance of heart rate during exercise for response to cardiac resynchronization therapy.

PubMed

Maass, Alexander H; Buck, Sandra; Nieuwland, Wybe; Brügemann, Johan; van Veldhuisen, Dirk J; Van Gelder, Isabelle C

2009-07-01

Cardiac resynchronization therapy (CRT) is an established therapy for patients with severe heart failure and mechanical dyssynchrony. Response is only achieved in 60-70% of patients. To study exercise-related factors predicting response to CRT. We retrospectively examined consecutive patients in whom a CRT device was implanted. All underwent cardiopulmonary exercise testing prior to implantation and after 6 months. The occurrence of chronotropic incompetence and heart rates exceeding the upper rate of the device, thereby compromising biventricular stimulation, was studied. Response was defined as a decrease in LVESV of 10% or more after 6 months. We included 144 patients. After 6 months 86 (60%) patients were responders. Peak VO2 significantly increased in responders. Chronotropic incompetence was more frequently seen in nonresponders (21 [36%] vs 9 [10%], P = 0.03), mostly in patients in SR. At moderate exercise, defined as 25% of the maximal exercise tolerance, that is, comparable to daily life exercise, nonresponders more frequently went above the upper rate of the device (13 [22%] vs 2 [3%], P < 0.0001), most of whom were patients in permanent AF. Multivariate analysis revealed heart rates not exceeding the upper rate of the device during moderate exercise (OR 15.8 [3.3-76.5], P = 0.001) and nonischemic cardiomyopathy (OR 2.4 [1.0-5.7], P = 0.04) as predictive for response. Heart rate exceeding the upper rate during moderate exercise is an independent predictor for nonresponse to CRT in patients with AF, whereas chronotropic incompetence is a predictor for patients in SR.

The Accuracy and Validity of iOS-Based Heart Rate Apps During Moderate to High Intensity Exercise.

PubMed

Bouts, Alexa M; Brackman, Lauren; Martin, Elizabeth; Subasic, Adam M; Potkanowicz, Edward S

2018-01-01

People use their smartphones for everything from web browsing to tracking fitness metrics. However, it is unclear whether smartphone-based apps that use photoplethysmography to measure heart rate are an accurate or valid measure of exercise intensity. Purpose was to determine the accuracy and validity of two iOS-based heart rate monitors, Runtastic Heart Rate Monitor and Pulse Tracker PRO by Runtastic (Runtastic) and Instant Heart Rate+: Heart Rate and Pulse Monitor by Azumio (Instant Heart Rate), when compared to the electrocardiogram (ECG) and Polar® T31 uncoded heart rate monitor from moderate to vigorous intensity exercise. Participants were 15 male and female regularly active college students. Pre-exercise heart rate and blood pressure were recorded and then participants exercised on a stationary bike at a pedal rate of between 50-60 rpms. After completing a warm-up stage at 40% of age estimated maximum heart rate (AEMHR), exercise intensity progressed from 50% of AEMHR through to 85% of AEMHR in eight, 5-minute stages. At the end of each stage, and having achieved steady-state, heart rates were recorded from each apparatus. After completing the final stage, participants completed a cooldown at 40% of their AEMHR. Post-exercise heart rate and blood pressure were also recorded to ensure full recovery to baseline. There was a strong positive correlation between the Polar® monitor and the ECG during all stages. However, there were not strong correlations for either of the smartphone-based apps at any time point. Although there were weak correlations between the smartphone-based apps and ECG and Polar®, further studies need to be conducted to determine if inaccuracy is due to user error (finger placement, finger temperature, etc.) or the technology behind the apps.

The Accuracy and Validity of iOS-Based Heart Rate Apps During Moderate to High Intensity Exercise

PubMed Central

BOUTS, ALEXA M.; BRACKMAN, LAUREN; MARTIN, ELIZABETH; SUBASIC, ADAM M.; POTKANOWICZ, EDWARD S.

2018-01-01

People use their smartphones for everything from web browsing to tracking fitness metrics. However, it is unclear whether smartphone-based apps that use photoplethysmography to measure heart rate are an accurate or valid measure of exercise intensity. Purpose was to determine the accuracy and validity of two iOS-based heart rate monitors, Runtastic Heart Rate Monitor and Pulse Tracker PRO by Runtastic (Runtastic) and Instant Heart Rate+: Heart Rate and Pulse Monitor by Azumio (Instant Heart Rate), when compared to the electrocardiogram (ECG) and Polar® T31 uncoded heart rate monitor from moderate to vigorous intensity exercise. Participants were 15 male and female regularly active college students. Pre-exercise heart rate and blood pressure were recorded and then participants exercised on a stationary bike at a pedal rate of between 50–60 rpms. After completing a warm-up stage at 40% of age estimated maximum heart rate (AEMHR), exercise intensity progressed from 50% of AEMHR through to 85% of AEMHR in eight, 5-minute stages. At the end of each stage, and having achieved steady-state, heart rates were recorded from each apparatus. After completing the final stage, participants completed a cooldown at 40% of their AEMHR. Post-exercise heart rate and blood pressure were also recorded to ensure full recovery to baseline. There was a strong positive correlation between the Polar® monitor and the ECG during all stages. However, there were not strong correlations for either of the smartphone-based apps at any time point. Although there were weak correlations between the smartphone-based apps and ECG and Polar®, further studies need to be conducted to determine if inaccuracy is due to user error (finger placement, finger temperature, etc.) or the technology behind the apps. PMID:29541341

Constrained choices? Linking employees' and spouses' work time to health behaviors.

PubMed

Fan, Wen; Lam, Jack; Moen, Phyllis; Kelly, Erin; King, Rosalind; McHale, Susan

2015-02-01

There are extensive literatures on work conditions and health and on family contexts and health, but less research asking how a spouse or partners' work conditions may affect health behaviors. Drawing on the constrained choices framework, we theorized health behaviors as a product of one's own time and spouses' work time as well as gender expectations. We examined fast food consumption and exercise behaviors using survey data from 429 employees in an Information Technology (IT) division of a U.S. Fortune 500 firm and from their spouses. We found fast food consumption is affected by men's work hours-both male employees' own work hours and the hours worked by husbands of women respondents-in a nonlinear way. The groups most likely to eat fast food are men working 50 h/week and women whose husbands work 45-50 h/week. Second, exercise is better explained if work time is conceptualized at the couple, rather than individual, level. In particular, neo-traditional arrangements (where husbands work longer than their wives) constrain women's ability to engage in exercise but increase odds of men exercising. Women in couples where both partners are working long hours have the highest odds of exercise. In addition, women working long hours with high schedule control are more apt to exercise and men working long hours whose wives have high schedule flexibility are as well. Our findings suggest different health behaviors may have distinct antecedents but gendered work-family expectations shape time allocations in ways that promote men's and constrain women's health behaviors. They also suggest the need to expand the constrained choices framework to recognize that long hours may encourage exercise if both partners are looking to sustain long work hours and that work resources, specifically schedule control, of one partner may expand the choices of the other. Copyright © 2014 Elsevier Ltd. All rights reserved.

Constrained Choices? Linking Employees' and Spouses' Work Time to Health Behaviors

PubMed Central

Fan, Wen; Lam, Jack; Moen, Phyllis; Kelly, Erin; King, Rosalind; McHale, Susan

2014-01-01

There are extensive literatures on work conditions and health and on family contexts and health, but less research asking how a spouse or partners' work conditions may affect health behaviors. Drawing on the constrained choices framework, we theorized health behaviors as a product of one's own time and spouses' work time as well as gender expectations. We examined fast food consumption and exercise behaviors using survey data from 429 employees in an Information Technology (IT) division of a U.S. Fortune 500 firm and from their spouses. We found fast food consumption is affected by men's work hours—both male employees' own work hours and the hours worked by husbands of women respondents—in a nonlinear way. The groups most likely to eat fast food are men working 50 hours/week and women whose husbands work 45-50 hours/week. Second, exercise is better explained if work time is conceptualized at the couple, rather than individual, level. In particular, neo-traditional arrangements (where husbands work longer than their wives) constrain women's ability to engage in exercise but increase odds of men exercising. Women in couples where both partners are working long hours have the highest odds of exercise. In addition, women working long hours with high schedule control are more apt to exercise and men working long hours whose wives have high schedule flexibility are as well. Our findings suggest different health behaviors may have distinct antecedents but gendered work-family expectations shape time allocations in ways that promote men's and constrain women's health behaviors. They also suggest the need to expand the constrained choices framework to recognize that long hours may encourage exercise if both partners are looking to sustain long work hours and that work resources, specifically schedule control, of one partner may expand the choices of the other. PMID:25531550

Influence of Upper-Body Exercise on the Fatigability of Human Respiratory Muscles

PubMed Central

TILLER, NICHOLAS B.; CAMPBELL, IAN G.; ROMER, LEE M.

2017-01-01

ABSTRACT Purpose Diaphragm and abdominal muscles are susceptible to contractile fatigue in response to high-intensity, whole-body exercise. This study assessed whether the ventilatory and mechanical loads imposed by high-intensity, upper-body exercise would be sufficient to elicit respiratory muscle fatigue. Methods Seven healthy men (mean ± SD; age = 24 ± 4 yr, peak O2 uptake [V˙O2peak] = 31.9 ± 5.3 mL·kg−1·min−1) performed asynchronous arm-crank exercise to exhaustion at work rates equivalent to 30% (heavy) and 60% (severe) of the difference between gas exchange threshold and V˙O2peak. Contractile fatigue of the diaphragm and abdominal muscles was assessed by measuring pre- to postexercise changes in potentiated transdiaphragmatic and gastric twitch pressures (Pdi,tw and Pga,tw) evoked by supramaximal magnetic stimulation of the cervical and thoracic nerves, respectively. Results Exercise time was 24.5 ± 5.8 min for heavy exercise and 9.8 ± 1.8 min for severe exercise. Ventilation over the final minute of heavy exercise was 73 ± 20 L·min−1 (39% ± 11% maximum voluntary ventilation) and 99 ± 19 L·min−1 (53% ± 11% maximum voluntary ventilation) for severe exercise. Mean Pdi,tw did not differ pre- to postexercise at either intensity (P > 0.05). Immediately (5–15 min) after severe exercise, mean Pga,tw was significantly lower than pre-exercise values (41 ± 13 vs 53 ± 15 cm H2O, P < 0.05), with the difference no longer significant after 25–35 min. Abdominal muscle fatigue (defined as ≥15% reduction in Pga,tw) occurred in 1/7 subjects after heavy exercise and 5/7 subjects after severe exercise. Conclusions High-intensity, upper-body exercise elicits significant abdominal, but not diaphragm, muscle fatigue in healthy men. The increased magnitude and prevalence of fatigue during severe-intensity exercise is likely due to additional (nonrespiratory) loading of the thorax. PMID:28288012

Influence of Upper-Body Exercise on the Fatigability of Human Respiratory Muscles.

PubMed

Tiller, Nicholas B; Campbell, Ian G; Romer, Lee M

2017-07-01

Diaphragm and abdominal muscles are susceptible to contractile fatigue in response to high-intensity, whole-body exercise. This study assessed whether the ventilatory and mechanical loads imposed by high-intensity, upper-body exercise would be sufficient to elicit respiratory muscle fatigue. Seven healthy men (mean ± SD; age = 24 ± 4 yr, peak O2 uptake [V˙O2peak] = 31.9 ± 5.3 mL·kg·min) performed asynchronous arm-crank exercise to exhaustion at work rates equivalent to 30% (heavy) and 60% (severe) of the difference between gas exchange threshold and V˙O2peak. Contractile fatigue of the diaphragm and abdominal muscles was assessed by measuring pre- to postexercise changes in potentiated transdiaphragmatic and gastric twitch pressures (Pdi,tw and Pga,tw) evoked by supramaximal magnetic stimulation of the cervical and thoracic nerves, respectively. Exercise time was 24.5 ± 5.8 min for heavy exercise and 9.8 ± 1.8 min for severe exercise. Ventilation over the final minute of heavy exercise was 73 ± 20 L·min (39% ± 11% maximum voluntary ventilation) and 99 ± 19 L·min (53% ± 11% maximum voluntary ventilation) for severe exercise. Mean Pdi,tw did not differ pre- to postexercise at either intensity (P > 0.05). Immediately (5-15 min) after severe exercise, mean Pga,tw was significantly lower than pre-exercise values (41 ± 13 vs 53 ± 15 cm H2O, P < 0.05), with the difference no longer significant after 25-35 min. Abdominal muscle fatigue (defined as ≥15% reduction in Pga,tw) occurred in 1/7 subjects after heavy exercise and 5/7 subjects after severe exercise. High-intensity, upper-body exercise elicits significant abdominal, but not diaphragm, muscle fatigue in healthy men. The increased magnitude and prevalence of fatigue during severe-intensity exercise is likely due to additional (nonrespiratory) loading of the thorax.

Taking a "Giant Tour" to Explore the Human Body

ERIC Educational Resources Information Center

Davies, Dan

2013-01-01

Helping children to visualise what is inside them and how their bodies work can be a challenge, since teachers are often reliant on secondary sources or investigations that can only measure outward signs (such as pulse rate). Another way is to involve the children in an imaginative role-play exercise where they explore the insides of a…

[Associations of the work duration, sleep duration and number of holidays with an exaggerated blood pressure response during an exercise stress test among workers].

PubMed

Michishita, Ryoma; Ohta, Masanori; Ikeda, Masaharu; Jiang, Ying; Yamato, Hiroshi

2016-01-01

It has been reported that an exaggerated systolic blood pressure (ESBP) response during exercise, even if resting blood pressure is normal, is associated with an increased risk of future hypertension and cardiovascular disease (CVD). This study was designed to investigate the relationships of work duration, sleep duration and number of holidays with blood pressure response during an exercise stress test among normotensive workers. The subjects were 362 normotensive workers (79 males and 283 females; age, 49.1 years). A multi-stage graded submaximal exercise stress test was performed on each subject using an electric bicycle ergometer. The workload was increased every 3 minutes, and blood pressure was measured at rest and during the last 1 minute of each stage. In this study, an ESBP response during exercise was defined according to the criteria of the Framingham Study (peak systolic blood pressure ≥210 mmHg in males, or ≥190 mmHg in females). Working environments, work duration, sleep duration, number of holidays, and physical activity during commuting and work, and leisure time exercise duration were evaluated using a questionnaire. An ESBP response during exercise was observed in 94 (26.0%) workers. The adjusted odds ratio for the prevalence of an ESBP response during exercise was found to be significantly higher with an increase in work duration, decreases in sleep duration and number of holidays (p<0.05, respectively). Moreover, the highest work duration with lowest sleep duration and number of holidays groups had significantly higher adjusted odds ratio for the prevalence of an ESBP response during exercise than the lowest work duration with highest sleep duration and number of holidays groups (p<0.05, respectively). Based on our results, we consider that the assessment of blood pressure response during exercise and daily life are necessary to prevent the incidence of future hypertension, CVD and death due to overwork in workers with long-work duration, short sleep duration and small number of holidays.

Clinical usefulness of end-tidal CO2 profiles during incremental exercise in patients with chronic thromboembolic pulmonary hypertension.

PubMed

Ramos, R P; Ferreira, E V M; Valois, F M; Cepeda, A; Messina, C M S; Oliveira, R K; Araújo, A T V; Teles, C A; Neder, J A; Nery, L E; Ota-Arakaki, J S

2016-11-01

Great ventilation to carbon dioxide output (ΔV˙E/ΔV˙CO 2 ) and reduced end-tidal partial pressures for CO 2 (PetCO 2 ) during incremental exercise are hallmarks of chronic thromboembolic pulmonary hypertension (CTEPH) and idiopathic pulmonary arterial hypertension (IPAH). However, CTEPH is more likely to involve proximal arteries, which may lead to poorer right ventricle-pulmonary vascular coupling and worse gas exchange abnormalities. Therefore, abnormal PetCO 2 profiles during exercise may be more prominent in patients with CTEPH and could be helpful to indicate disease severity. Seventy patients with CTEPH and 34 with IPAH underwent right heart catheterization and cardiopulmonary exercise testing. According to PetCO 2 pattern during exercise, patients were classified as having an increase or stabilization in PetCO 2 up to the gas exchange threshold (GET), an abrupt decrease in the rest-exercise transition or a progressive and slow decrease throughout exercise. A subgroup of patients with CTEPH underwent a constant work rate exercise test to obtain arterial blood samples during steady-state exercise. Multivariate logistic regression analyses showed that progressive decreases in PetCO 2 and SpO 2 were better discriminative parameters than ΔV˙E/ΔV˙CO 2 to distinguish CTEPH from IPAH. This pattern of PetCO 2 was associated with worse functional impairment and greater reduction in PaCO 2 during exercise. Compared to patients with IPAH, patients with CTEPH present more impaired gas exchange during exercise, and PetCO 2 abnormalities may be used to identify more clinically and hemodynamically severe cases. Copyright © 2016 Elsevier Ltd. All rights reserved.

Measurement of Functional Capacity Requirements of Farmers: IMPLICATIONS FOR A CARDIAC REHABILITATION TRAINING PROGRAM.

PubMed

Jordan, Shannon; Karcher, Justin; Rogers, Rebecca; Kennedy, Kathleen; Lawrence, Anne; Adams, Jenny

2017-03-01

Updated cardiac rehabilitation (CR) and return-to-work guidelines from the American College of Sports Medicine (ACSM) now include specificity of training for industrial athletes (exercise training that involves the muscle groups, movements, and energy systems that these patients use during occupational tasks). However, many CR facilities do not apply this principle, relying instead on the traditional protocol that consists primarily of aerobic exercise. This study was conducted to measure the metabolic cost of typical farming tasks and to compare 2 methods of calculating training intensities. Metabolic data were collected from 28 participants (23 men and 5 women, aged 18 to 57 years) while they loaded 10 hay bales, dug a fence posthole, filled 8 seed hoppers, and shoveled grain. Mean metabolic equivalent levels during these activities were 5.9 to 7.6 and participants reached 60% to 70% of heart rate reserve (HRR). By comparison, their mean resting heart rate + 30 beats per minute (RHR+30, a traditional CR intensity level) represented only 28% of HRR. Participants in the current study performed farming tasks within the ACSM's recommended range of 40% to 80% of HRR, and the results suggest that training at RHR+30 would have been inadequate for helping a farmer return to work after a cardiac event. Using the study tasks as a basis, we described exercises that would be appropriate for the supervised resistance training of farmers in a CR setting.

Psychosocial benefits of workplace physical exercise: cluster randomized controlled trial.

PubMed

Jakobsen, Markus D; Sundstrup, Emil; Brandt, Mikkel; Andersen, Lars L

2017-10-10

While benefits of workplace physical exercise on physical health is well known, little is known about the psychosocial effects of such initiatives. This study evaluates the effect of workplace versus home-based physical exercise on psychosocial factors among healthcare workers. A total of 200 female healthcare workers (Age: 42.0, BMI: 24.1) from 18 departments at three hospitals were cluster-randomized to 10 weeks of: 1) home-based physical exercise (HOME) performed alone during leisure time for 10 min 5 days per week or 2) workplace physical exercise (WORK) performed in groups during working hours for 10 min 5 days per week and up to 5 group-based coaching sessions on motivation for regular physical exercise. Vitality and mental health (SF-36, scale 0-100), psychosocial work environment (COPSOQ, scale 0-100), work- and leisure disability (DASH, 0-100), control- (Bournemouth, scale 0-10) and concern about pain (Pain Catastrophizing Scale, scale 0-10) were assessed at baseline and at 10-week follow-up. Vitality as well as control and concern about pain improved more following WORK than HOME (all p < 0.05) in spite of increased work pace (p < 0.05). Work- and leisure disability, emotional demands, influence at work, sense of community, social support and mental health remained unchanged. Between-group differences at follow-up (WORK vs. HOME) were 7 [95% confidence interval (95% CI) 3 to 10] for vitality, -0.8 [95% CI -1.3 to -0.3] for control of pain and -0.9 [95% CI -1.4 to -0.5] for concern about pain, respectively. Performing physical exercise together with colleagues during working hours was more effective than home-based exercise in improving vitality and concern and control of pain among healthcare workers. These benefits occurred in spite of increased work pace. NCT01921764 at ClinicalTrials.gov . Registered 10 August 2013.

Changes in muscle activation patterns and subjective low back pain ratings during prolonged standing in response to an exercise intervention.

PubMed

Nelson-Wong, Erika; Callaghan, Jack P

2010-12-01

Low back pain (LBP) development has been associated with occupational standing. Increased hip and trunk muscle co-activation is considered to be predisposing for LBP development during standing in previously asymptomatic individuals. The purpose of this work was to investigate muscle activation and LBP responses to a prescribed exercise program. Pain-developing (PD) individuals were expected to have decreased LBP and muscle co-activation following exercise intervention. Electromyography (EMG) data were recorded from trunk and hip muscle groups during 2-h of standing. An increase of >10mm on visual analog scale (VAS) during standing was threshold for PD categorization. Participants were assigned to progressive exercise program with weekly supervision or control (usual activity) for 4 weeks then re-tested. Forty percent were categorized as PD on day 1, VAS=24.2 (±4.0)mm. PD exercisers (PDEX) had lower VAS scores (8.93±3.66 mm) than PD control (PDCON) (16.5±6.3 mm) on day 2 (p=0.007). Male PDEX had decreased gluteus medius co-activation levels (p<0.05) on day 2. The exercise program proved beneficial in reducing LBP during standing. There were changes in muscle activation patterns previously associated with LBP. Predisposing factors for LBP during standing were shown to change positively with appropriate exercise intervention. Copyright © 2010 Elsevier Ltd. All rights reserved.

Caffeine Increases Work Done above Critical Power, but Not Anaerobic Work.

PubMed

Silveira, Rodrigo; Andrade-Souza, Victor Amorim; Arcoverde, Lucyana; Tomazini, Fabiano; Sansonio, André; Bishop, David John; Bertuzzi, Romulo; Lima-Silva, Adriano Eduardo

2018-01-01

The assumption that the curvature constant (W') of the power-duration relationship represents anaerobic work capacity is a controversial, unresolved question. We investigated if caffeine ingestion could increase total work done above critical power (CP), and if this would be accompanied by greater anaerobic energy expenditure and by an enhanced maintenance of maximal oxidative metabolic rate. Nine men (26.6 ± 5.3 yr, V˙O2max 40.6 ± 5.8 mL·kg·min) cycled until exhaustion at different exercise intensities on different days to determine the CP and W'. On separated days, participants cycled until exhaustion in the severe-intensity domain (136% ± 7% of CP) after ingesting either caffeine (5 mg·kg body mass) or a placebo. Time to exhaustion was 34% longer with caffeine compared with placebo, and this was accompanied by a greater work done above CP (23.7 ± 5.7 vs 17.5 ± 3.6 kJ; 130% ± 30% vs 95% ± 14% of W', P < 0.01). Caffeine increased the aerobic energy expenditure (296.4 ± 91.0 vs 210.2 ± 71.9 kJ, P < 0.01), but not anaerobic lactic, anaerobic alactic, and total anaerobic (lactic + alactic) energy expenditure. The end values of heart rate and ventilation were higher with caffeine, but the V˙O2 end was similar between conditions and was not different from V˙O2max. Caffeine did not change time to reach V˙O2max but increased time maintained at V˙O2max (199.3 ± 105.9 vs 111.9 ± 87.1 s, P < 0.05). Caffeine increased total work done above CP, but this was not associated with greater anaerobic work. Rather, this was associated with a higher tolerance to maintain exercise at maximal oxidative metabolic rate.

Self-Reported Participation in Sport/Exercise Among Adolescents and Young Adults With and Without Mild to Moderate Intellectual Disability.

PubMed

Robertson, Janet; Emerson, Eric; Baines, Susannah; Hatton, Chris

2018-04-01

Physical inactivity is a leading risk factor for mortality. Adults with intellectual disability are extremely inactive, but less is known about physical activity levels in children and youth with intellectual disability. This paper examines the participation by adolescents and young adults with and without mild to moderate intellectual disability in sport/exercise. Secondary analysis was undertaken of Next Steps, an annual panel study that followed a cohort from early adolescence into adulthood. Participants with mild to moderate intellectual disability were identified through data linkage with educational records. Sport/exercise participation rates were consistently lower for adolescents and young people with mild to moderate intellectual disability than for their peers without intellectual disability. Matching participants on between-group differences in exposure to extraneous risk factors did not impact on these between-group differences in participation in sport/exercise. The results support limited existing evidence regarding the low level of participation of children and young people with intellectual disability in sport/exercise compared with their peers. Future work on promoting sport/exercise and physical activity in children and young people with intellectual disability may play a role in helping to reduce the health inequalities experienced by people with intellectual disability.

Effects of reading health and appearance exercise magazine articles on perceptions of attractiveness and reasons for exercise.

PubMed

Pankratow, Melanie; Berry, Tanya R; McHugh, Tara-Leigh F

2013-01-01

To examine the effects of reading exercise-related magazine articles (health, appearance, or control) and the moderating effects of exercise self-identity on reasons for exercise and perceptions of attractiveness, among women in first year university. An additional purpose was to use a thought listing technique, the results of which were examined for evidence of internalization of the exercise-related messages. Female students in their first year of studies between September 2010 and April 2011 (N = 173; mean age = 19.31 years, mean body mass index = 22.01). Participants read a health, appearance, or control article, listed thoughts, and completed questionnaires measuring reasons for exercising, physical self-perception, and exercise self-identity. Participants in the health condition rated exercise for health significantly higher than control condition participants. Participants with high exercise self-identity rated attractiveness as a reason for exercising significantly higher than low exercise self-identity participants in both the health and appearance conditions. Participants with higher internalization scores (i.e., accepted societal norms of appearance) reported exercising for attractiveness reasons more so than participants with lower internalization scores. The good news is that health messages may be influential and result in wanting to exercise for health purposes. However, exercising for attractiveness was rated highly by participants with high exercise identity who read either the health or appearance articles. Health and appearance are not necessarily distinct concepts for female undergraduate students and the media may influence cited reasons for exercise.

Under Construction: An Experiential Exercise Illustrating Elements of Work Design

ERIC Educational Resources Information Center

Donovan, Kimberly M.; Fluegge-Woolf, Erin R.

2015-01-01

The Under Construction Exercise was developed by the authors to highlight key factors of work design that when implemented among the work group or entire organization can lead to an environment conducive to fostering satisfaction and motivation. In the exercise, groups are assigned to one of four different conditions that are designed to emulate…

Exercise thermoregulation in men after 6 hours of immersion

NASA Technical Reports Server (NTRS)

Greenleaf, J. E.; Spaul, W. A.; Kravik, S. E.; Wong, N.; Elder, C. A.

1985-01-01

The present investigation is concerned with thermoregulation at rest and during exercise after water-immersion deconditioning, giving particular attention to the effects of fluid shifts and negative water balance on sweat rate and rectal temperature. Six healthy males 20-35 years old were used in the experiments. Rectal and mean skin temperature, skin heat conductance, heart rate, and total body sweat rate were measured during 70 min of supine leg exercise at 50 percent of peak O2 uptake. The data were taken after a 6-h control period in air and after immersion to the neck in water (34.5 C) for 6 h after overnight food and fluid restriction. Attention is given to end exercise heart rates and data during exercise. The obtained results suggest that, compared with control responses, the equilibrium level of core temperature during submaximal exercise is regulated at a higher level after immersion.

Validation of Heart Rate Monitor Polar RS800 for Heart Rate Variability Analysis During Exercise.

PubMed

Hernando, David; Garatachea, Nuria; Almeida, Rute; Casajús, Jose A; Bailón, Raquel

2018-03-01

Hernando, D, Garatachea, N, Almeida, R, Casajús, JA, and Bailón, R. Validation of heart rate monitor Polar RS800 for heart rate variability analysis during exercise. J Strength Cond Res 32(3): 716-725, 2018-Heart rate variability (HRV) analysis during exercise is an interesting noninvasive tool to measure the cardiovascular response to the stress of exercise. Wearable heart rate monitors are a comfortable option to measure interbeat (RR) intervals while doing physical activities. It is necessary to evaluate the agreement between HRV parameters derived from the RR series recorded by wearable devices and those derived from an electrocardiogram (ECG) during dynamic exercise of low to high intensity. Twenty-three male volunteers performed an exercise stress test on a cycle ergometer. Subjects wore a Polar RS800 device, whereas ECG was also recorded simultaneously to extract the reference RR intervals. A time-frequency spectral analysis was performed to extract the instantaneous mean heart rate (HRM), and the power of low-frequency (PLF) and high-frequency (PHF) components, the latter centered on the respiratory frequency. Analysis was done in intervals of different exercise intensity based on oxygen consumption. Linear correlation, reliability, and agreement were computed in each interval. The agreement between the RR series obtained from the Polar device and from the ECG is high throughout the whole test although the shorter the RR is, the more differences there are. Both methods are interchangeable when analyzing HRV at rest. At high exercise intensity, HRM and PLF still presented a high correlation (ρ > 0.8) and excellent reliability and agreement indices (above 0.9). However, the PHF measurements from the Polar showed reliability and agreement coefficients around 0.5 or lower when the level of the exercise increases (for levels of O2 above 60%).

Comparison of three methods to identify the anaerobic threshold during maximal exercise testing in patients with chronic heart failure.

PubMed

Beckers, Paul J; Possemiers, Nadine M; Van Craenenbroeck, Emeline M; Van Berendoncks, An M; Wuyts, Kurt; Vrints, Christiaan J; Conraads, Viviane M

2012-02-01

Exercise training efficiently improves peak oxygen uptake (V˙O2peak) in patients with chronic heart failure. To optimize training-derived benefit, higher exercise intensities are being explored. The correct identification of anaerobic threshold is important to allow safe and effective exercise prescription. During 48 cardiopulmonary exercise tests obtained in patients with chronic heart failure (59.6 ± 11 yrs; left ventricular ejection fraction, 27.9% ± 9%), ventilatory gas analysis findings and lactate measurements were collected. Three technicians independently determined the respiratory compensation point (RCP), the heart rate turning point (HRTP) and the second lactate turning point (LTP2). Thereafter, exercise intensity (target heart rate and workload) was calculated and compared between the three methods applied. Patients had significantly reduced maximal exercise capacity (68% ± 21% of predicted V˙O2peak) and chronotropic incompetence (74% ± 7% of predicted peak heart rate). Heart rate, workload, and V˙O2 at HRTP and at RCP were not different, but at LTP2, these parameters were significantly (P < 0.0001) higher. Mean target heart rate and target workload calculated using the LTP2 were 5% and 12% higher compared with those calculated using HRTP and RCP, respectively. The calculation of target heart rate based on LTP2 was 5% and 10% higher in 12 of 48 (25%) and 6 of 48 (12.5%) patients, respectively, compared with the other two methods. In patients with chronic heart failure, RCP and HRTP, determined during cardiopulmonary exercise tests, precede the occurrence of LTP2. Target heart rates and workloads used to prescribe tailored exercise training in patients with chronic heart failure based on LTP2 are significantly higher than those derived from HRTP and RCP.

Acute and Post-Exercise Physiological Responses to High-Intensity Interval Training in Endurance and Sprint Athletes

PubMed Central

Cipryan, Lukas; Tschakert, Gerhard; Hofmann, Peter

2017-01-01

The purpose of the presented study was to compare acute and post-exercise differences in cardiorespiratory, metabolic, cardiac autonomic, inflammatory and muscle damage responses to high-intensity interval exercise (HIIT) between endurance and sprint athletes. The study group consisted of sixteen highly-trained males (age 22.1 ± 2.5 years) participating in endurance (n = 8) or sprint (n = 8) sporting events. All the participants underwent three exercise sessions: short HIIT (work interval duration 30s), long HIIT (3min) and constant load exercise (CE). The exercise interventions were matched for mean power, total time and in case of HIIT interventions also for work-to-relief ratio. The acute cardiorespiratory (HR, V̇O2, RER) and metabolic (lactate) variables as well as the post-exercise changes (up to 3 h) in the heart rate variability, inflammation (interleukin-6, leucocytes) and muscle damage (creatine kinase, myoglobin) were monitored. Endurance athletes performed exercise interventions with moderately (CE) or largely (both HIIT modes) higher mean V̇O2. These differences were trivial/small when V̇O2 was expressed as a percentage of V̇O2max. Moderately to largely lower RER and lactate values were found in endurance athletes. Markers of cardiac autonomic regulation, inflammation and muscle damage did not reveal any considerable differences between endurance and sprint athletes. In conclusions, endurance athletes were able to perform both HIIT formats with increased reliance on aerobic metabolic pathways although exercise intensity was identical in relative terms for all the participants. However, other markers of the acute and early post-exercise physiological response to these HIIT interventions indicated similarities between endurance and sprint athletes. Key points The manner in which each training background (endurance vs. sprint) influences the response to HIIT is not well known. Despite the identical exercise intensity in relative terms, endurance athletes are able to perform HIIT with increased reliance on aerobic metabolic pathways when compared to sprint athletes. The mean V̇O2 (% V̇O2max) and HR as well as markers of the cardiac autonomic regulation, systemic inflammation and muscle damage monitored during the early recovery phase did not demonstrate any differences between endurance and sprint trained individuals. PMID:28630575

The role of exercise in fall prevention for older adults.

PubMed

Rose, Debra J; Hernandez, Danielle

2010-11-01

This article reviews the evidence for the effectiveness of stand-alone exercise interventions and multifactorial intervention strategies that include exercise in lowering fall incidence rates and/or fall risk among older adults residing in the community, acute, subacute, and long-term care settings. Stand-alone exercise programs that emphasize multiple exercise categories are effective in reducing fall rates and fall risk in community-residing older adults, and may also be effective when conducted for a sufficient duration with older adult patients in subacute settings. In contrast, multifactorial fall risk reduction programs that include exercise as a component and are delivered by a multidisciplinary team are more effective in lowering fall rates in long-term care settings. Copyright © 2010 Elsevier Inc. All rights reserved.

The Effects of Supplementation with a Vitamin and Mineral Complex with Guaraná Prior to Fasted Exercise on Affect, Exertion, Cognitive Performance, and Substrate Metabolism: A Randomized Controlled Trial.

PubMed

Veasey, Rachel C; Haskell-Ramsay, Crystal F; Kennedy, David O; Wishart, Karl; Maggini, Silvia; Fuchs, Caspar J; Stevenson, Emma J

2015-07-27

Exercise undertaken in a fasted state can lead to higher post-exercise mental fatigue. The administration of a vitamin and mineral complex with guaraná (MVM + G) has been shown to attenuate mental fatigue and improve performance during cognitively demanding tasks. This placebo-controlled, double-blind, randomized, balanced cross-over study examined the effect of MVM + G consumed prior to morning exercise on cognitive performance, affect, exertion, and substrate metabolism. Forty active males (age 21.4 ± 3.0 year; body mass index (BMI) 24.0 ± 2.4 kg/m2; maximal oxygen consumption (V̇O2max) 57.6 ± 7.3 mL/min/kg) completed two main trials, consuming either MVM + G or placebo prior to a 30-min run at 60% V̇O2max. Supplementation prior to exercise led to a small but significant reduction in Rating of Perceived Exertion (RPE) during exercise compared to the placebo. The MVM + G combination also led to significantly increased accuracy of numeric working memory and increased speed of picture recognition, compared to the placebo. There were no significant effects of supplementation on any other cognitive or mood measures or on substrate metabolism during exercise. These findings demonstrate that consuming a vitamin and mineral complex containing guaraná, prior to exercise, can positively impact subsequent memory performance and reduce perceived exertion during a moderate-intensity run in active males.

The Effects of Supplementation with a Vitamin and Mineral Complex with Guaraná Prior to Fasted Exercise on Affect, Exertion, Cognitive Performance, and Substrate Metabolism: A Randomized Controlled Trial

PubMed Central

Veasey, Rachel C.; Haskell-Ramsay, Crystal F.; Kennedy, David O.; Wishart, Karl; Maggini, Silvia; Fuchs, Caspar J.; Stevenson, Emma J.

2015-01-01

Exercise undertaken in a fasted state can lead to higher post-exercise mental fatigue. The administration of a vitamin and mineral complex with guaraná (MVM + G) has been shown to attenuate mental fatigue and improve performance during cognitively demanding tasks. This placebo-controlled, double-blind, randomized, balanced cross-over study examined the effect of MVM + G consumed prior to morning exercise on cognitive performance, affect, exertion, and substrate metabolism. Forty active males (age 21.4 ± 3.0 year; body mass index (BMI) 24.0 ± 2.4 kg/m2; maximal oxygen consumption (V̇O2max) 57.6 ± 7.3 mL/min/kg) completed two main trials, consuming either MVM + G or placebo prior to a 30-min run at 60% V̇O2max. Supplementation prior to exercise led to a small but significant reduction in Rating of Perceived Exertion (RPE) during exercise compared to the placebo. The MVM + G combination also led to significantly increased accuracy of numeric working memory and increased speed of picture recognition, compared to the placebo. There were no significant effects of supplementation on any other cognitive or mood measures or on substrate metabolism during exercise. These findings demonstrate that consuming a vitamin and mineral complex containing guaraná, prior to exercise, can positively impact subsequent memory performance and reduce perceived exertion during a moderate-intensity run in active males. PMID:26225993

Health, lifestyle and employment beyond state-pension age.

PubMed

Demou, Evangelia; Bhaskar, Abita; Xu, Taoye; Mackay, Daniel F; Hunt, Kate

2017-12-20

The factors influencing one's choice to retire vary, with financial and health considerations being some of the main factors impacting or associated with people's timing of retirement. The aim of the study is to investigate the differences in current health and health-related behaviours, such as smoking, drinking and exercising, between people who kept on working beyond state-pension age and those who retired before or at state-pension age. Data from six waves (2003, 2008-2012) of the Scottish Health Survey (SHeS) are used. Descriptive analyses were used to characterise the population. Multivariate logistic regression was undertaken to analyse the relationship between retirement groups and gender, age, deprivation, marital status, housing tenure, general health, longstanding illness, cigarette smoking status, amount of exercise and mental health, using Stata. Reporting poor self-rated health or having a long-standing illness was associated with increased odds of retiring before state pension age (SPA) in groups with a medium deprivation profile in almost all the survey years. For the least deprived there was little evidence of an association between poor health and extended-working-life, while significant associations were observed for the most deprived. An increasing trend was observed for both genders in the number of people extending their working life. Similar associations between reporting poorer self-rated health and extended working lives were observed for men and women. Distinct gender differences were observed for the associations with reporting poor mental health and no exercise. In the adjusted models, both were significantly associated with retiring at or before SPA in almost every year for women, whereas no significant associations were observed (except in 1 year) for men. This study shows an increasing trend in the number of people extending their working lives and demonstrates significant associations between health and lifestyle behaviours and employment status past SPA. The results suggest that good health - both physically and mentally - along with either a need or a want to stay in employment could be important reasons for continuing to work beyond SPA.

Perceived Exercise Benefits and Barriers of Non-Exercising Female University Students in the United Kingdom

PubMed Central

Lovell, Geoff P; Ansari, Walid El; Parker, John K

2010-01-01

Many individuals do not engage in sufficient physical activity due to low perceived benefits and high perceived barriers to exercise. Given the increasing incidence of obesity and obesity related health disorders, this topic requires further exploration. We used the Exercise Benefits/Barriers Scale to assess perceived benefit and barrier intensities to exercise in 200 non-exercising female university students (mean age 19.3 years, SD = 1.06) in the UK. Although our participants were selected because they self reported themselves to be non-exercising, however they reported significantly higher perceived benefits from exercise than perceived barriers to exercise [t(199) = 6.18, p < 0.001], and their perceived benefit/barrier ratio was 1.33. The greatest perceived benefit from exercise was physical performance followed by the benefits of psychological outlook, preventive health, life enhancement, and then social interaction. Physical performance was rated significantly higher than all other benefits. Psychological outlook and preventive health were not rated significantly different, although both were significantly higher than life enhancement and social interaction. Life enhancement was also rated significantly higher than social interaction. The greatest perceived barrier to exercise was physical exertion, which was rated significantly higher than time expenditure, exercise milieu, and family discouragement barriers. Implications from this investigation for the design of physical activity programmes include the importance, for females, of a perception of high benefit/barrier ratio that could be conducive to participation in exercise. Applied interventions need to assist female students to ‘disengage’ from or overcome any perceived ‘unpleasantness’ of physical exertion during physical activity (decrease their perceived barriers), and to further highlight the multiple health and other benefits of regular exercising (increase their perceived benefits). PMID:20617003

Perceived exercise benefits and barriers of non-exercising female university students in the United Kingdom.

PubMed

Lovell, Geoff P; El Ansari, Walid; Parker, John K

2010-03-01

Many individuals do not engage in sufficient physical activity due to low perceived benefits and high perceived barriers to exercise. Given the increasing incidence of obesity and obesity related health disorders, this topic requires further exploration. We used the Exercise Benefits/Barriers Scale to assess perceived benefit and barrier intensities to exercise in 200 non-exercising female university students (mean age 19.3 years, SD = 1.06) in the UK. Although our participants were selected because they self reported themselves to be non-exercising, however they reported significantly higher perceived benefits from exercise than perceived barriers to exercise [t(199) = 6.18, p < 0.001], and their perceived benefit/barrier ratio was 1.33. The greatest perceived benefit from exercise was physical performance followed by the benefits of psychological outlook, preventive health, life enhancement, and then social interaction. Physical performance was rated significantly higher than all other benefits. Psychological outlook and preventive health were not rated significantly different, although both were significantly higher than life enhancement and social interaction. Life enhancement was also rated significantly higher than social interaction. The greatest perceived barrier to exercise was physical exertion, which was rated significantly higher than time expenditure, exercise milieu, and family discouragement barriers. Implications from this investigation for the design of physical activity programmes include the importance, for females, of a perception of high benefit/barrier ratio that could be conducive to participation in exercise. Applied interventions need to assist female students to 'disengage' from or overcome any perceived 'unpleasantness' of physical exertion during physical activity (decrease their perceived barriers), and to further highlight the multiple health and other benefits of regular exercising (increase their perceived benefits).

Revisiting the Pink Triangle Exercise: An Exploration of Experiential Learning in Graduate Social Work Education

ERIC Educational Resources Information Center

Pugh, Greg L.

2014-01-01

The pink triangle exercise is an example of an experiential learning exercise that creates cognitive dissonance and deep learning of unrealized internalized biases among social work students. Students wear a button with a pink triangle on it for 1 day and write a reflection paper. The exercise increases self-awareness, cultural competence, and the…

Hand therapist management of the lateral epicondylosis: a survey of expert opinion and practice patterns.

PubMed

MacDermid, Joy C; Wojkowski, Sarah; Kargus, Cristin; Marley, Meghan; Stevenson, Emily

2010-01-01

Lateral epicondylosis (LE) is a common condition. Knowledge on practice patterns underlies identification of knowledge to practice gaps. The purpose was to determine the practice patterns and beliefs of hand therapists in managing LE. The study design used was a descriptive survey. A survey of Certified Hand Therapists and members of the American Society of Hand Therapists was conducted (n=693). Questions were framed around frequency and perceived effectiveness of interventions, examination techniques, outcome measures, and prognostic factors. More than 80% of therapists use education/activity modification, home exercise, LE orthoses, and stretching for both the acute and chronic LE. Therapists perceive education, orthoses and home exercise are the most effective for acute cases, whereas in chronic cases, orthoses dropped to ninth in ranked perceived effectiveness. Grip strength (80%) and numeric pain rating (71%) were the most commonly used outcome measures. Most (>70%) therapists perceived occupation and duration of symptoms are prognostic in terms of resolution of symptoms, whereas compliance with exercise (78%) and work factors are important for return to work. Therapists rely on impairment measures to evaluate hand therapy outcomes in patients with LE. Hand therapists are aligned with a number of recommendations from the available systematic reviews, although the use of outcome measures and optimal definition of education and exercise exhibit evidence to practice gaps. Level 5. Copyright (c) 2010 Hanley & Belfus. Published by Elsevier Inc. All rights reserved.

Barriers to performing stretching exercises among Korean-Chinese female migrant workers in Korea.

PubMed

Lee, Hyeonkyeong; Wilbur, JoEllen; Chae, Duckhee; Lee, Kyongeun; Lee, Meenhye

2015-01-01

The purpose of this study was to investigate the barriers to performing stretching exercise experienced by Korean-Chinese female migrant workers during a community-based 12-week stretching exercise intervention trial. Qualitative secondary data analysis was conducted using telephone counseling interview transcripts from 27 middle-aged, Korean-Chinese migrant women workers. A semistructured interview question asking barriers to performing stretching exercise was given to women who did not adhere to recommended stretching exercise. During the 12-week home-based stretching exercise intervention trial, six telephone calls were made to participants biweekly to elicit barriers to performing stretching exercise. Directed content analysis approach was utilized using three barrier categories: intrapersonal, interpersonal, and work-related environmental factors based on the ecological model. Participants experienced an average of 2.5 barriers during the study period. Intrapersonal barriers included lack of time and lack of motivation, and interpersonal barriers included no family to provide support and also a feeling resistance from coworkers. Work-related environmental barriers included frequent job changes, long working hours, lack of rest time, and unpredictable job demands. The findings highlight that migrant workers in Korea face unique work-related difficulties which present barriers to exercise. © 2014 Wiley Periodicals, Inc.

Effect of exercise type on smoking cessation: a meta-analysis of randomized controlled trials.

PubMed

Klinsophon, Thaniya; Thaveeratitham, Premtip; Sitthipornvorakul, Ekalak; Janwantanakul, Prawit

2017-09-06

Exercise is one choice of additional treatment for smoking cessation by relieving nicotine withdrawal symptoms and smoking craving. The possible mechanism of the effect of exercise on relieving nicotine withdrawal symptoms and smoking craving is including affect, biological, and cognitive hypotheses. Evidence suggests that different types of exercise have different effects on these mechanisms. Therefore, type of exercise might have effect on smoking cessation. The purpose of this study is to systematically review randomized controlled trials to gain insight into which types of exercise are effective for smoking cessation. Publications were systemically searched up to November 2016 in several databases (PubMed, ScienceDirect, PEDro, Web of Science, Scopus and Cochrane Library), using the following keywords: "physical activity", "exercise", "smoking", "tobacco" and "cigarette". The methodological quality was assessed independently by two authors. Meta-analysis was conducted to examine the effectiveness of the type of exercise on smoking cessation. The quality of the evidence was assessed and rated according to the GRADE approach. 20 articles on 19 studies were judged to meet the selection criteria (seven low-risk of bias RCTs and 12 high-risk of bias RCTs). The findings revealed low quality evidence for the effectiveness of yoga for smoking cessation at the end of the treatment. The evidence found for no effect of aerobic exercise, resisted exercise, and a combined aerobic and resisted exercise program on smoking cessation was of low to moderate quality. Furthermore, very low to low quality evidence was found for no effect of physical activity on smoking cessation. There was no effect of aerobic exercise, resisted exercise, physical activity and combined aerobic and resisted exercise on smoking cessation. There was a positive effect on smoking cessation at the end of treatment in the program where yoga plus cognitive-behavioral therapy (CBT) was used. However, which of the two work is still to be studied.

Reference values for blood pressure response to cycle ergometry in the first two decades of life: comparison with patients with a repaired coarctation of the aorta.

PubMed

Kaafarani, Mirna; Schroer, Christian; Takken, Tim

2017-12-01

Hemodynamic responses to exercise are used as markers of diagnosis for cardiac diseases, systolic blood pressure (SBP) especially. However, the reference values for SBP in children at peak exertion level are outdated. This study aimed to establish current reference values for SBP, rate pressure product (RPP), and circulatory power (CircP). Data from children who previously underwent cardiopulmonary exercise testing were categorized as healthy (N = 184; age 12.6 ± 2.9 years), and CoA patients (N = 25; age 13.0 ± 3.2 years). With the Lambda-Mu-Sigma (LMS) method, percentile curves were made for SBP, CircP, and RPP in function of peak work rate (Wpeak). Data of CoA patients were used to validate the reference values. Wpeak was the best predictor of peak SBP during exercise. The prediction equations for SBP, CircP and RPP were: (0.2853 x Wpeak) + 111.46; (10.56 x Wpeak) + 2550.2 and (61.879 x Wpeak) + 19.887, respectively. CoA patients showed significantly increased values for peak SBP (Z-score 1.063 ± 1.347). This study provides reference values for SBP, RPP, and CircP at peak exercise. These values can be used for objective evaluation of participants 6-18 years of age in a Dutch population.

Participation in and Satisfaction With an Exercise Program for Inpatient Mental Health Consumers.

PubMed

Stanton, Robert; Donohue, Trish; Garnon, Michelle; Happell, Brenda

2016-01-01

This study examines attendance at, and satisfaction with, a group exercise program in an inpatient mental health setting. Thirty-two inpatients completed discharge surveys to evaluate group activities. Data were analyzed for participation and satisfaction. More inpatients (n = 16, 50%) rated exercise as "excellent" compared with all other activities. Nonattendance rates were lowest for cognitive behavioral therapy (n = 2, 6.3%), highest for the relaxation group (n = 6, 18.8%), and 12.5% (n = 4) for the group exercise program. Group exercise programs delivered by highly trained personnel are well attended and achieve high satisfaction ratings by inpatient mental health consumers. © 2015 Wiley Periodicals, Inc.

Influence of music on maximal self-paced running performance and passive post-exercise recovery rate.

PubMed

Lee, S; Kimmerly, D

2014-10-30

The purpose of this study was to examine the influence of fast tempo music (FM) on self--paced running performance (heart rate, running speed, ratings of perceived exertion), and slow tempo music (SM) on post--exercise heart rate and blood lactate recovery rates. Twelve participants (5 Women) completed three randomly assigned conditions: static noise (control), FM and SM. Each condition consisted of self--paced treadmill running, and supine post--exercise recovery periods (20 min each). Average running speed, heart rate (HR) and ratings of perceived exertion (RPE) were measured during the treadmill running period, while HR and blood lactate were measured during the recovery period. Listening to FM during exercise resulted in a faster self--selected running speed (10.8 ± 1.7 vs. 9.9 ± 1.4 km•hour--1, p<0.001) and higher peak HR (184 ± 12 vs. 177 ± 17 beats•min--1, p< 0.01) without a corresponding difference in peak RPE (FM, 16.8 ± 1.8 vs. SM 15.7 ± 1.9, p= 0.10). Listening to SM during the post--exercise period reduced HR throughout (main effect p<0.001) and blood lactate at the end of recovery (2.8 ± 0.4 vs. 4.7 ± 0.8 mmol•L--1, p<0.05). Listening to FM during exercise can increase self--paced intensity without altering perceived exertion levels while listening to SM after exercise can accelerate the recovery rate back to resting levels.

Exercise/recreation facility for a lunar or Mars analog

NASA Technical Reports Server (NTRS)

1991-01-01

The University of Idaho, NASA/USRA project for the 1990-91 school year is an exercise/recreation station for an Earth-based simulator of a lunar or martian habitat. Specifically, a stationary bicycle that will help people keep fit and prevent muscular atrophy while stationed in space was designed. To help with motivation and provide an element of recreation during the workout, the bicycle is to be enhanced by a virtual reality system. The system simulates various riding situations, including the choice of a mountain bike or a road bike. The bike employs a magnetic brake that provides continuously changing tension to simulate actual riding conditions. This braking system is interfaced directly with the virtual reality system. Also, integrated into the virtual reality display will be a monitoring system that regulates heart rate, work rate, and other functions during the course of the session.

MRS evidence of adequate O2 supply in human skeletal muscle at the onset of exercise

PubMed Central

Richardson, Russell S.; Wary, Claire; Wray, D. Walter; Hoff, Jan; Rossiter, Harry; Layec, Gwenael; Carlier, Pierre G.

2015-01-01

Purpose At exercise onset, intramuscular oxidative energy production responds relatively slowly in comparison to the change in ATP demand. To determine if the slow kinetics of oxidative ATP production is due to inadequate O2 supply or metabolic inertia we studied the kinetics of intramyocellular deoxygenation (deoxy-myoglobin, Mb) and metabolism (phosphocreatine, PCr), using proton (1H) and phosphorus (31P) magnetic resonance spectroscopy (MRS) in 6 healthy subjects (33 ± 5 yrs). Methods Specifically, utilizing dynamic plantar flexion exercise, rest to exercise and recovery was assessed at both 60% of maximum work rate (WRmax) (moderate intensity) and 80% of WRmax (heavy intensity). Results At exercise onset [PCr] fell without delay and with a similar time constant (τ) at both exercise intensities (~33 s). In contrast, the increase in deoxy-Mb was delayed at exercise onset by 5–7 s, after which it increased with kinetics (moderate τ = 37 ± 9 s, and heavy τ = 29 ± 6 s) that were not different from τPCr (p > 0.05). At cessation, deoxy-Mb recovered without a time delay and more rapidly (τ ~20 s) than PCr (τ ~33 s) (p < 0.05). Conclusion using a unique combination of in vivo MRS techniques with high time-resolution, this study revealed a delay in intramuscular de-oxygenation at the onset of exercise, and rapid re-oxygenation kinetics upon cessation. Together these data imply that intramuscular substrate-enzyme interactions, and not O2 availability, determine the exercise onset kinetics of oxidative metabolism in healthy human skeletal muscle. PMID:25830362

Prescribing water-based exercise from treadmill and arm ergometry in cardiac patients.

PubMed

Fernhall, B; Manfredi, T G; Congdon, K

1992-01-01

This study investigated the appropriateness of prescribing upright water-based exercise from treadmill and arm ergometry in uncomplicated, trained patients with cardiovascular disease (CVD) who were accustomed to water-based activities. Ten male patients with established CVD (mean age 59.4 +/- 8.7 yr) underwent maximal treadmill and arm ergometry in randomized counterbalanced order (half of the patients completed the treadmill test first and the other half completed the arm ergometer test first). Electrocardiographic (ECG), rating of perceived exertion (RPE), and oxygen uptake (VO2) measurements were made during both tests. Patients performed upright water-based exercise at 60, 70, and 80% of their maximal treadmill heart rate for 6 min at each intensity in a heated pool with a water temperature of 28-30 degrees C. They also performed an easy tethered swim, defined as performing at a comfortable exercise intensity, eliciting a heart rate of 86% of the treadmill maximum. VO2 and RPE were collected for all water-based exercise. To compare the RPE and VO2 between water-based, treadmill, and arm ergometry exercise, individual regression equations were constructed between heart rate, VO2, and RPE for both treadmill and arm ergometry tests. VO2 and RPE were then compared at the same heart rates between the three exercise modes. At 60% intensity, treadmill exercise exhibited a higher VO2 than water-based and arm ergometry exercise (P less than 0.05) but similar RPE. At 70%, treadmill exercise still yielded higher VO2, but also lower RPE than (P less than 0.05) and arm ergometry exercise (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Active play exercise intervention in children with asthma: a PILOT STUDY

PubMed Central

Westergren, Thomas; Fegran, Liv; Nilsen, Tonje; Haraldstad, Kristin; Kittang, Ole Bjørn; Berntsen, Sveinung

2016-01-01

Objective Increased physical activity (PA) may be beneficial for children with asthma. Knowledge about how to intervene and encourage children with asthma to be physically active is required. In the present study, we aimed to pilot a 6-week exercise intervention designed as active play and examine attendance rate, exercise intensity and children's perceptions of participating. Methods 6 children with asthma (4 boys, 2 girls) aged 10–12 years, participated in 60 min of active play exercise twice weekly. A mixed-methods design was applied. The data analysed included attendance rate, exercise intensity assessed by heart rate (HR) monitoring during exercise sessions, registration and description of the active play exercise programme, 3 semistructured focus groups, field observations of 5 exercise sessions, and preintervention and postintervention testing. Findings The average attendance rate was 90%. Intensity ≥80% of maximal HR (HRmax) was recorded for a median (IQR) time of 22 (8) out of 60 min per session. Median (IQR) HR during the sessions was 146 (9; 74% of HRmax) bpm. Children reported increased health-related quality of life (HRQoL) post-test compared with baseline. Children enjoyed participating and reported no limitations by asthma or serious asthma attacks. Instead, they perceived that their asthma and fitness had improved after the programme. The instructors created an inclusive atmosphere that was characterised by easy-to-master games, fair competition, humour and mutual participation. Conclusions The exercise intervention pilot focusing on active play had a high attendance rate, relatively high exercise intensity, and satisfaction; the children perceived that their fitness and asthma had improved, and reported increased HRQoL. A randomised controlled trial of active play exercise including children with asthma should be conducted to evaluate effect on PA level, physical fitness, asthma control and HRQoL. PMID:26733570

Myocardial blood flow and its transit time, oxygen utilization, and efficiency of highly endurance-trained human heart.

PubMed

Heinonen, Ilkka; Kudomi, Nobuyuki; Kemppainen, Jukka; Kiviniemi, Antti; Noponen, Tommi; Luotolahti, Matti; Luoto, Pauliina; Oikonen, Vesa; Sipilä, Hannu T; Kopra, Jaakko; Mononen, Ilkka; Duncker, Dirk J; Knuuti, Juhani; Kalliokoski, Kari K

2014-07-01

Highly endurance-trained athlete's heart represents the most extreme form of cardiac adaptation to physical stress, but its circulatory alterations remain obscure. In the present study, myocardial blood flow (MBF), blood mean transit time (MTT), oxygen extraction fraction (OEF) and consumption (MVO2), and efficiency of cardiac work were quantified in highly trained male endurance athletes and control subjects at rest and during supine cycling exercise using [(15)O]-labeled radiotracers and positron emission tomography. Heart rate and MBF were lower in athletes both at rest and during exercise. OEF increased in response to exercise in both groups, but was higher in athletes (70 ± 21 vs. 63 ± 11 % at rest and 86 ± 13 vs. 73 ± 10 % during exercise). MTT was longer and vascular resistance higher in athletes both at rest and during exercise, but arterial content of 2,3-diphosphoglycerate (oxygen affinity) was unchanged. MVO2 per gram of myocardium trended (p = 0.08) lower in athletes both at rest and during exercise, while myocardial efficiency of work and MVO2 per beat were not different between groups. Arterial levels of free fatty acids were ~twofold higher in athletes likely leading to higher myocardial fatty acid oxidation and hence oxygen cost, which may have blunted the bradycardia-induced decrease in MVO2. Finally, the observed group differences in MBF, OEF, MTT and vascular resistance remained significant also after they were controlled for differences in MVO2. In conclusion, in highly endurance-trained human heart, increased myocardial blood transition time enables higher oxygen extraction levels with a lower myocardial blood flow and higher vascular resistance. These physiological adaptations to exercise training occur independently of the level of oxygen consumption and together with training-induced bradycardia may serve as mechanisms to increase functional reserve of the human heart.

Neurobiological mechanisms of exercise and psychotherapy in depression: The SPeED study-Rationale, design, and methodological issues.

PubMed

Heinzel, Stephan; Rapp, Michael A; Fydrich, Thomas; Ströhle, Andreas; Terán, Christina; Kallies, Gunnar; Schwefel, Melanie; Heissel, Andreas

2018-02-01

Even though cognitive behavioral therapy has become a relatively effective treatment for major depressive disorder and cognitive behavioral therapy-related changes of dysfunctional neural activations were shown in recent studies, remission rates still remain at an insufficient level. Therefore, the implementation of effective augmentation strategies is needed. In recent meta-analyses, exercise therapy (especially endurance exercise) was reported to be an effective intervention in major depressive disorder. Despite these findings, underlying mechanisms of the antidepressant effect of exercise especially in combination with cognitive behavioral therapy have rarely been studied to date and an investigation of its neural underpinnings is lacking. A better understanding of the psychological and neural mechanisms of exercise and cognitive behavioral therapy would be important for developing optimal treatment strategies in depression. The SPeED study (Sport/Exercise Therapy and Psychotherapy-evaluating treatment Effects in Depressive patients) is a randomized controlled trial to investigate underlying physiological, neurobiological, and psychological mechanisms of the augmentation of cognitive behavioral therapy with endurance exercise. It is investigated if a preceding endurance exercise program will enhance the effect of a subsequent cognitive behavioral therapy. This study will include 105 patients diagnosed with a mild or moderate depressive episode according to the Diagnostic and Statistical Manual of Mental Disorders (4th ed.). The participants are randomized into one of three groups: a high-intensive or a low-intensive endurance exercise group or a waiting list control group. After the exercise program/waiting period, all patients receive an outpatient cognitive behavioral therapy treatment according to a standardized therapy manual. At four measurement points, major depressive disorder symptoms (Beck Depression Inventory, Hamilton Rating Scale for Depression), (neuro)biological measures (neural activations during working memory, monetary incentive delay task, and emotion regulation, as well as cortisol levels and brain-derived neurotrophic factor), neuropsychological test performance, and questionnaires (psychological needs, self-efficacy, and quality of life) are assessed. In this article, we report the design of the SPeED study and refer to important methodological issues such as including both high- and low-intensity endurance exercise groups to allow the investigation of dose-response effects and physiological components of the therapy effects. The main aims of this research project are to study effects of endurance exercise and cognitive behavioral therapy on depressive symptoms and to investigate underlying physiological and neurobiological mechanisms of these effects. Results may provide important implications for the development of effective treatment strategies in major depressive disorder, specifically concerning the augmentation of cognitive behavioral therapy by endurance exercise.

Physical Activity and Exercise Interventions in the Workplace Impacting Work Outcomes: A Stakeholder-Centered Best Evidence Synthesis of Systematic Reviews.

PubMed

White, M I; Dionne, C E; Wärje, O; Koehoorn, M; Wagner, S L; Schultz, I Z; Koehn, C; Williams-Whitt, K; Harder, H G; Pasca, R; Hsu, V; McGuire, L; Schulz, W; Kube, D; Wright, M D

2016-04-01

The prevention of work disability is beneficial to employees and employers, and mitigates unnecessary societal costs associated with social welfare. Many service providers and employers have initiated workplace interventions designed to reduce unnecessary work disability. To conduct a best-evidence synthesis of systematic reviews on workplace interventions that address physical activities or exercise and their impact on workplace absence, work productivity or financial outcomes. Using a participatory research approach, academics and stakeholders identified inclusion and exclusion criteria, built an abstraction table, evaluated systematic review quality and relevance, and interpreted the combined findings. A minimum of two scientists participated in a methodological review of the literature followed by a consensus process. Stakeholders and researchers participated as a collaborative team. 3363 unique records were identified, 115 full text articles and 46 systematic reviews were included, 18 assessed the impact of physical fitness or exercise interventions. 11 focused on general workers rather than workers who were absent from work at baseline; 16 of the reviews assessed work absence, 4 assessed productivity and 6 assessed financial impacts. The strongest evidence supports the use of short, simple exercise or fitness programs for both workers at work and those absent from work at baseline. For workers at work, simple exercise programs (1-2 modal components) appear to provide similar benefits to those using more complex multimodal interventions. For workers off-work with subacute low back pain, there is evidence that some complex exercise programs may be more effective than simple exercise interventions, especially if they involve workplace stakeholder engagement, communication and coordination with employers and other stakeholders. The development and utilization of standardized definitions, methods and measures and blinded evaluation would improve research quality and strengthen stakeholder-centered guidance.

Supported treadmill ambulation for amyotrophic lateral sclerosis: a pilot study.

PubMed

Sanjak, Mohammed; Bravver, Elena; Bockenek, William L; Norton, H James; Brooks, Benjamin R

2010-12-01

To determine the feasibility, tolerability, safety, and exercise treatment-effect size of repetitive rhythmic exercise mediated by supported treadmill ambulation training (STAT) for patients with amyotrophic lateral sclerosis (ALS). Interventional with repeated-measures design. Multidisciplinary ALS clinic at academic medical center. Convenience sample of patients with ALS (N=9) who were ambulatory with assistive devices (Sinaki-Mulder stages II-III). Repetitive rhythmic exercise-STAT (30min total; 5min of exercise intercalated with 5min of rest) performed 3 times a week for 8 weeks. ALS Functional Rating Scale-Revised (ALSFRS-R), percentage of predicted vital capacity (VC), total lower-extremities manual muscle test (MMT), rate of perceived exertion (RPE), Fatigue Severity Scale (FSS), and maximum voluntary isometric contraction (MVIC) in 10 lower and 10 upper extremities. Gait performance, which included walking distance, speed, steps, and stride length, was evaluated during treadmill and ground 6-minute walk tests (6MWTs) and 25-foot walk test (25FWT). Feasibility issues decreased screened participants by 4 patients (31%). Nine patients were enrolled, but 6 patients (67%) completed the study and 3 (23% of original cohort; 33% of enrolled cohort) could not complete the exercise intervention because of non-ALS-related medical problems. Tolerability of the intervention measures during the treadmill 6MWT showed improvement in RPE (P≤.05) and FSS score (P≥.05). Safety measures (ALSFRS-R, VC, MMT) showed no decrease and showed statistical improvement in ALSFRS-R score (P≤.05) during the study interval. Exercise treatment-effect size showed variable improvements. Gait speed, distance, and stride length during the treadmill 6MWT improved significantly (P≤.05) after 4 weeks and improvements were maintained after 8 weeks compared with baseline. Walking distance during the ground 6MWT increased significantly after 4 weeks and was maintained after 8 weeks compared with baseline (P≤.05). Walking speed during the 25FWT and lower-extremity MVIC improved, but were not statistically significant. Repetitive rhythmic exercise-STAT is feasible, tolerated, and safe for patients with ALS. Repetitive rhythmic exercise-STAT treatment-effect size across a number of ALS-related measures was consistent with improved work capacity and gait function in patients with ALS who are dependent on assistive devices for ambulation. Repetitive rhythmic exercise-STAT should be evaluated further in larger studies to determine the stability of this improved function in relation to the rate of progression of the underlying ALS. Copyright © 2010 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Appropriateness of the metabolic equivalent (MET) as an estimate of exercise intensity for post-myocardial infarction patients.

PubMed

Woolf-May, Kate; Meadows, Steve

2016-01-01

To explore: (1) whether during exercise metabolic equivalents (METs) appropriately indicate the intensity and/or metabolic cost for post-myocardial infarction (MI) males and (2) whether post-exercise VO 2 parameters provide insight into the intensity and/or metabolic cost of the prior exercise. 15 male phase-IV post-MIs (64.4±6.5 years) and 16 apparently healthy males (63.0±6.4 years) participated. Participants performed a graded cycle ergometer test (CET) of 50, 75 and 100 W, followed by 10 min active recovery (at 50 W) and 22 min seated recovery. Participants' heart rate (HR, bpm), expired air parameters and ratings of perceived exertion (exercise only) were measured. General linear model analysis showed throughout significantly lower HR values in post-MI participants that were related to β-blocker medication ( F (2,5) =18.47, p<0.01), with significantly higher VCO 2 /VO 2 ( F (2,5) =11.25, p<0.001) and gross kcals/LO 2 /min ( F (2,5) =11.25, p<0.001). Analysis comparing lines of regression showed, during the CET: post-MI participants worked at higher percentage of their anaerobic threshold (%AT)/MET than controls ( F (2,90) =18.98, p<0.001), as well as during active recovery (100-50 W) ( F (2,56) =20.81, p<0.001); during seated recovery: GLM analysis showed significantly higher values of VCO 2 /VO 2 for post-MI participants compared with controls ( F (2,3) =21.48, p=0.001) as well as gross kcals/LO 2 /min ( F (2,3) =21.48, p=0.001). Since METs take no consideration of any anaerobic component, they failed to reflect the significantly greater anaerobic contribution during exercise per MET for phase-IV post-MI patients. Given the anaerobic component will be greater for those with more severe forms of cardiac disease, current METs should be used with caution when determining exercise intensity in any patient with cardiac disease.

Physiological Comparison of Concentric and Eccentric Arm Cycling in Males and Females

PubMed Central

Beaven, C. Martyn; Willis, Sarah J.; Cook, Christian J.; Holmberg, Hans-Christer

2014-01-01

Lower body eccentric exercise is well known to elicit high levels of muscular force with relatively low cardiovascular and metabolic strain. As a result, eccentric exercise has been successfully utilised as an adaptive stressor to improve lower body muscle function in populations ranging from the frail and debilitated, to highly-trained individuals. Here we investigate the metabolic, cardiorespiratory, and energy costs of upper body eccentric exercise in a healthy population. Seven men and seven women performed 4-min efforts of eccentric (ECC) or concentric (CON) arm cycling on a novel arm ergometer at workloads corresponding to 40, 60, and 80% of their peak workload as assessed in an incremental concentric trial. The heart rate, ventilation, cardiac output, respiratory exchange ratio, and blood lactate concentrations were all clearly greater in CON condition at all of the relative workloads (all p<0.003). Effect size calculations demonstrated that the magnitude of the differences in VO2 and work economy between the ECC and CON exercise ranged from very large to extremely large; however, in no case did mechanical efficiency (ηMECH) differ between the conditions (all p>0.05). In contrast, delta efficiency (ηΔ), as previously defined by Coyle and colleagues in 1992, demonstrated a sex difference (men>women; p<0.05). Sex differences were also apparent in arteriovenous oxygen difference and heart rate during CON. Here, we reinforce the high-force, low cost attributes of eccentric exercise which can be generalised to the muscles of the upper body. Upper body eccentric exercise is likely to form a useful adjunct in debilitative, rehabilitative, and adaptive clinical exercise programs; however, reports of a shift towards an oxidative phenotype should be taken into consideration by power athletes. We suggest delta efficiency as a sensitive measure of efficiency that allowed the identification of sex differences. PMID:25372404

A Cycling Movement Based System for Real-Time Muscle Fatigue and Cardiac Stress Monitoring and Analysis

PubMed Central

Chen, Szi-Wen; Liaw, Jiunn-Woei; Chang, Ya-Ju; Chan, Hsiao-Lung; Chiu, Li-Yu

2015-01-01

In this study, we defined a new parameter, referred to as the cardiac stress index (CSI), using a nonlinear detrended fluctuation analysis (DFA) of heart rate (HR). Our study aimed to incorporate the CSI into a cycling based fatigue monitoring system developed in our previous work so the muscle fatigue and cardiac stress can be both continuously and quantitatively assessed for subjects undergoing the cycling exercise. By collecting electrocardiogram (ECG) signals, the DFA scaling exponent α was evaluated on the RR time series extracted from a windowed ECG segment. We then obtained the running estimate of α by shifting a one-minute window by a step of 20 seconds so the CSI, defined as the percentage of all the less-than-one α values, can be synchronously updated every 20 seconds. Since the rating of perceived exertion (RPE) scale is considered as a convenient index which is commonly used to monitor subjective perceived exercise intensity, we then related the Borg RPE scale value to the CSI in order to investigate and quantitatively characterize the relationship between exercise-induced fatigue and cardiac stress. Twenty-two young healthy participants were recruited in our study. Each participant was asked to maintain a fixed pedaling speed at a constant load during the cycling exercise. Experimental results showed that a decrease in DFA scaling exponent α or an increase in CSI was observed during the exercise. In addition, the Borg RPE scale and CSI were positively correlated, suggesting that the factors due to cardiac stress might also contribute to fatigue state during physical exercise. Since the CSI can effectively quantify the cardiac stress status during physical exercise, our system may be used in sports medicine, or used by cardiologists who carried out stress tests for monitoring heart condition in patients with heart diseases. PMID:26115515

[Effects of long-term Tai Ji Quan exercise on automatic nervous modulation in the elderly].

PubMed

Guo, Feng

2015-03-01

To examine the effects of long-term Tai Ji Quan (Chinnese Traditional Exercise) on automatic nervous modulation in the elders. The 18 subjects from Tai Ji Quan exercise class in Liaoning University of Retired Veteran Cadres were assigned into long-term Tai Ji Quan exercise group including 10 subjects and novice group including 8 subjects. Electrocardiography, respiratory and blood pressure data were collected on the following time points: at rest before Tai Ji Qhuan exercise and 30 min or 60 min after Tai Ji Quan exercise. The subjects at rest state in the long-term Tai Ji Quan exercise group showed higher than the subjects in the novice group in resperitory rate (RR), standard deviations of normal to normal intervals (SDNN), total power (TP), low frequency power (LFP), high frequency power (HFP), normalized high frequency power (nHFP), but lower in LFP/HFP, systolic and diastolic blood pressure, and heart rate. At rest state the respiratory rate of subjects in long-term Tai Ji Quan exercise group was significantly lower than the novices. After Tai Ji Quan exercise, TP, nHFP, LFP/HFP, heart rate and systolic pressure showed significantly changes, and the change level of Tai Ji Quan on these indices was larger in Tai Ji Quan exercise group than that in the novice group. Long-term Tai Ji Quan exercise can improve vagal modulations, and tend to reduce the sympathetic modulations.

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.

Entrepreneurs' self-reported health, social life, and strategies for maintaining good health.

PubMed

Gunnarsson, Kristina; Josephson, Malin

2011-01-01

This study investigated the association between self-reported good health and self-valued good social life. An additional aim was to examine entrepreneur's strategies for maintaining good health. The study design included a two-wave questionnaire, with five years between the surveys (2001 and 2006), and qualitative interviews. The study group consisted of 246 entrepreneurs from the central region of Sweden and represented ten different trades. Entrepreneurs reporting good health in both 2001 and 2006 were compared with entrepreneurs reporting poor health on both occasions or with inconsistent answers. Six of the entrepreneurs were strategically chosen for the interview study. Consistent good health was reported by 56% of the entrepreneurs. Good social life in 2001 was associated with an increased odds ratio (OR) for consistent good health when the analyses were adjusted for physical work conditions and job satisfaction (OR 2.12, 95% CI 1.07-4.17). Findings for good leisure time, weekly moderate physical exercise, and a rating of work being less or equally important as other life areas, were similar but not statistically significant when job satisfaction was considered in the analyses. Strategies for maintaining good health included good planning and control over work, flexibility at work, good social contact with family, friends and other entrepreneurs, and regular physical exercise. This study demonstrated an association between self-reported good health and good social life for entrepreneurs in small-scale enterprises. In addition, the entrepreneurs emphasised strategies such as planning and control over work and physical exercise are important for maintaining good health.

Effect of gender on fatigue and recovery following maximal intensity repeated sprint performance.

PubMed

Laurent, C M; Green, J M; Bishop, P A; Sjökvist, J; Schumacker, R E; Richardson, M T; Curtner-Smith, M

2010-09-01

This study investigated the effects of gender on repeated, maximal-intensity intermittent sprint exercise following variable day-to-day recovery periods. Sixteen volunteers (8 men, 8 women) performed four trials of high-intensity intermittent sprint exercise consisting of three bouts of eight 30 m sprints (total of 24 sprints). Following completion of the baseline trial, in repeated-measures design, participants were assigned, in counter-balanced order, variable recovery periods of 24, 48, and 72 h whereupon they repeated an identical exercise trial. Results from a series of 4 (trial) x 3 (bout) repeated measures ANOVAs revealed men produced significantly (P < 0.01) faster times throughout all bouts and trials of repeated sprint exercise. Additionally, women exhibited significantly lower (P < 0.05) blood lactate concentration and significantly lower (P < 0.05) decrement in performance, indicating increased resistance to fatigue during repeated exercise sessions. There were no significant differences (P > 0.05) between genders for heart rate or rating of perceived exertion during or following trials. There were no significant differences for overall sprint performance within either gender among trials. These results indicate men, while able to produce higher absolute power outputs (i.e., lower sprint time), demonstrate higher decrement scores within a trial compared to women, thus suggesting women may recover faster and fatigue less. Also, gender differences affecting recovery within in a trial were observed to be diminished between trials (i.e., day-to-day recovery) of maximal intermittent sprint work evidenced by the observed stability of performance between trials following various recovery durations.

The relationship between different exercise modes and visuospatial working memory in older adults: a cross-sectional study.

PubMed

Guo, Wei; Wang, Biye; Lu, Yue; Zhu, Qin; Shi, Zhihao; Ren, Jie

2016-01-01

The purpose of the study was to investigate the relationship between different exercise modes and visuospatial working memory in healthy older adults. A cross-sectional design was adopted. A total of 111 healthy older adults were enrolled in the study. They were classified by the exercise-related questionnaire to be in an open-skill group, closed-skill group or sedentary group. In experiment 1, the participants performed a visuospatial working memory task. The results indicated that both closed-skill (p < 0.05) and open-skill (p < 0.01) groups reached a higher accuracy than the sedentary group. Experiment 2 examined whether the exercise-induced benefit of working memory was manifested in passive maintenance or active manipulation of working memory which was assessed by visuospatial short-term memory task and visuospatial mental rotation task, respectively. The results showed that the open-skill (p < 0.01) group was more accurate than the sedentary group in the visuospatial short-term memory task, whereas the group difference in the visuospatial mental rotation task was not significant. These findings combined to suggest that physical exercise was associated with better visuospatial working memory in older adults. Furthermore, open-skill exercises that demand higher cognitive processing showed selective benefit for passive maintenance of working memory.

Neck strength recovery after a single bout of specific strengthening exercise.

PubMed

Netto, Kevin; Carstairs, Greg; Kidgell, Dawson; Aisbett, Brad

2010-08-01

To determine the level of neck strength decrement and the rate of strength recovery of the neck muscles after a single bout of specific neck conditioning exercise in both males and females. A decrement in neck strength may be evident after a bout of strengthening exercise. Intervention study with pre-and-post design. Biomechanics laboratory. Twenty healthy participants (10 male and 10 female, mean +/- standard deviation age 22 +/- 1.2 years). Participants performed a single bout of neck strengthening exercise. Neck strength testing using an isokinetic dynamometer was performed pre and at five time points (1 h, one, three, five and seven days) post-exercise to assess the level of neck strength decrement and neck strength recovery rate from pre-exercise levels. Statistically significant (p > or = 0.036) decreases in neck extension strength were recorded in all participants 1 h and one day post-exercise. The level of neck extension strength returned to pre-exercise levels three days post-exercise and surpassed pre-exercise levels five and seven days post-exercise. The male participants' neck flexion strength decrement and recovery followed a similar pattern to that displayed in neck extension but more variability in neck flexion strength recovery rates were recorded in the female participants in this study. The consistent strength recovery times for the male participants recorded in this study idealise the prescription of neck strengthening exercises in a periodised fashion. More investigation needs to be instigated for the female neck musculature as consistent strength recovery rates were not identified in this study. 2010 Elsevier Ltd. All rights reserved.

Effects of isotonic and isometric exercises with mist sauna bathing on cardiovascular, thermoregulatory, and metabolic functions

NASA Astrophysics Data System (ADS)

Iwase, Satoshi; Kawahara, Yuko; Nishimura, Naoki; Nishimura, Rumiko; Sugenoya, Junichi; Miwa, Chihiro; Takada, Masumi

2014-08-01

To clarify the effects of isometric and isotonic exercise during mist sauna bathing on the cardiovascular function, thermoregulatory function, and metabolism, six healthy young men (22 ± 1 years old, height 173 ± 4 cm, weight 65.0 ± 5.0 kg) were exposed to a mist sauna for 10 min at a temperature of 40 °C, and relative humidity of 100 % while performing or not performing ˜30 W of isometric or isotonic exercise. The effect of the exercise was assessed by measuring tympanic temperature, heart rate, systolic and diastolic blood pressure, chest sweat rate, chest skin blood flow, and plasma catecholamine and cortisol, glucose, lactate, and free fatty acid levels. Repeated measures ANOVA showed no significant differences in blood pressure, skin blood flow, sweat rate, and total amount of sweating. Tympanic temperature increased more during isotonic exercise, and heart rate increase was more marked during isotonic exercise. The changes in lactate indicated that fatigue was not very great during isometric exercise. The glucose level indicated greater energy expenditure during isometric exercise. The free fatty acid and catecholamine levels indicated that isometric exercise did not result in very great energy expenditure and stress, respectively. The results for isotonic exercise of a decrease in lactate level and an increase in plasma free fatty acid level indicated that fatigue and energy expenditure were rather large while the perceived stress was comparatively low. We concluded that isotonic exercise may be a more desirable form of exercise during mist sauna bathing given the changes in glucose and free fatty acid levels.

Endometrial cancer survivors' assessment of the benefits of exercise.

PubMed

Lukowski, Jessica; Gil, Karen M; Jenison, Eric; Hopkins, Michael; Basen-Engquist, Karen

2012-03-01

The majority of women who have had endometrial cancer remain at risk for obesity related diseases. The social cognitive theory was used to explore their beliefs about exercise to aid in the development of effective interventions. Women who had been treated for Stage I endometrial cancer were asked about their level of exercise to determine if they had been exercising regularly for more than 6 months (exercisers vs non-exercisers). They were asked to rate the likelihood that exercise would result in various health outcomes (expectations) and to rate the importance of these outcomes (expectancies). Scores for how likely exercise would result in an outcome of importance were calculated. Height and weight were obtained from nurses for calculation of BMI. Statistics were conducted using SPSS v 15. There were 106 valid questionnaires (86% participation rate); 41% were exercisers. Mean BMI was significantly lower in exercisers (31.6 ± 1.2 vs. 37.3 ± 1.2, p=0.001); a significantly greater proportion reported not having diabetes, heart disease or hypertension (69.8% vs. 49.2%, p=0.035). Exercisers were significantly more likely to report that feeling better physically and emotionally versus reducing the risk of diseases were likely and important outcomes of exercise (18.2 ± 0.8 vs 15.0 ± 1.0, p=0.002). Exercisers identified outcomes of exercise that are more immediate and subjective as being important and likely outcomes of exercise. Focusing on these aspects of exercise (feeling better physically and emotionally) may aid in the development of effective interventions for non-exercisers. Copyright © 2011. Published by Elsevier Inc.

Effects of Reading Health and Appearance Exercise Magazine Articles on Perceptions of Attractiveness and Reasons for Exercise

PubMed Central

Pankratow, Melanie; Berry, Tanya R.; McHugh, Tara-Leigh F.

2013-01-01

Objective To examine the effects of reading exercise-related magazine articles (health, appearance, or control) and the moderating effects of exercise self-identity on reasons for exercise and perceptions of attractiveness, among women in first year university. An additional purpose was to use a thought listing technique, the results of which were examined for evidence of internalization of the exercise-related messages. Participants Female students in their first year of studies between September 2010 and April 2011 (N = 173; mean age = 19.31 years, mean body mass index = 22.01). Methods Participants read a health, appearance, or control article, listed thoughts, and completed questionnaires measuring reasons for exercising, physical self-perception, and exercise self-identity. Results Participants in the health condition rated exercise for health significantly higher than control condition participants. Participants with high exercise self-identity rated attractiveness as a reason for exercising significantly higher than low exercise self-identity participants in both the health and appearance conditions. Participants with higher internalization scores (i.e., accepted societal norms of appearance) reported exercising for attractiveness reasons more so than participants with lower internalization scores. Conclusions The good news is that health messages may be influential and result in wanting to exercise for health purposes. However, exercising for attractiveness was rated highly by participants with high exercise identity who read either the health or appearance articles. Health and appearance are not necessarily distinct concepts for female undergraduate students and the media may influence cited reasons for exercise. PMID:23630618

Exercise and vitamin D in fall prevention among older women: a randomized clinical trial.

PubMed

Uusi-Rasi, Kirsti; Patil, Radhika; Karinkanta, Saija; Kannus, Pekka; Tokola, Kari; Lamberg-Allardt, Christel; Sievänen, Harri

2015-05-01

While vitamin D supplementation and exercise are recommended for prevention of falls for older people, results regarding these 2 factors are contradictory. To determine the effectiveness of targeted exercise training and vitamin D supplementation in reducing falls and injurious falls among older women. A 2-year randomized, double-blind, placebo-controlled vitamin D and open exercise trial conducted between April 2010 and March 2013 in Tampere, Finland. Participants were 409 home-dwelling women 70 to 80 years old. The main inclusion criteria were at least 1 fall during the previous year, no use of vitamin D supplements, and no contraindication to exercise. Four study groups, including placebo without exercise, vitamin D (800 IU/d) without exercise, placebo and exercise, and vitamin D (800 IU/d) and exercise. The primary outcome was monthly reported falls. Injurious falls and the number of fallers and injured fallers were reported as secondary outcomes. In addition, bone density, physical functioning (muscle strength, balance, and mobility), and vitamin D metabolism were assessed. Intent-to-treat analyses showed that neither vitamin D nor exercise reduced falls. Fall rates per 100 person-years were 118.2, 132.1, 120.7, and 113.1 in the placebo without exercise, vitamin D without exercise, placebo and exercise, and vitamin D and exercise study groups, respectively; however, injurious fall rates were 13.2, 12.9, 6.5, and 5.0, respectively. Hazard ratios for injured fallers were significantly lower among exercisers with vitamin D (0.38; 95% CI, 0.17-0.83) and without vitamin D (0.47; 95% CI, 0.23-0.99). Vitamin D maintained femoral neck bone mineral density and increased tibial trabecular density slightly. However, only exercise improved muscle strength and balance. Vitamin D did not enhance exercise effects on physical functioning. The rate of injurious falls and injured fallers more than halved with strength and balance training in home-dwelling older women, while neither exercise nor vitamin D affected the rate of falls. Exercise improved physical functioning. Future research is needed to determine the role of vitamin D in the enhancement of strength, balance, and mobility. clinicaltrials.gov Identifier: NCT00986466.

Effects of posture on exercise performance - Measurement by systolic time intervals.

NASA Technical Reports Server (NTRS)

Spodick, D. H.; Quarry-Pigott, V. M.

1973-01-01

Because posture significantly influences cardiac performance, the effects of moderate supine and upright ergometer exercise were compared on the basis of proportional (+37%) rate increments over resting control. Supine exercise produced significant decreases in left ventricular ejection time (LVET), pre-ejection period (PEP), and isovolumic contraction time (IVCT). Ejection time index (ETI) and corrected ejection time (LVETc) did not change significantly. Upright exercise produced greater decreases in PEP and LVET, but despite the rate increase there was no change in LVET, which resulted in sharp increases in ETI and LVETc. The discordant directional effects on LVET and its rate-correcting indices between the two postures were consistent with hemodynamic studies demonstrating lack of stroke volume change during supine exercise and increased stroke volume over control during light to moderate upright exercise.

Cardiovascular mortality prediction in veterans with arm exercise vs pharmacologic myocardial perfusion imaging.

PubMed

Martin, Wade H; Xian, Hong; Chandiramani, Pooja; Bainter, Emily; Klein, Andrew J P

2015-08-01

No data exist comparing outcome prediction from arm exercise vs pharmacologic myocardial perfusion imaging (MPI) stress test variables in patients unable to perform treadmill exercise. In this retrospective study, 2,173 consecutive lower extremity disabled veterans aged 65.4 ± 11.0years (mean ± SD) underwent either pharmacologic MPI (1730 patients) or arm exercise stress tests (443 patients) with MPI (n = 253) or electrocardiography alone (n = 190) between 1997 and 2002. Cox multivariate regression models and reclassification analysis by integrated discrimination improvement (IDI) were used to characterize stress test and MPI predictors of cardiovascular mortality at ≥10-year follow-up after inclusion of significant demographic, clinical, and other variables. Cardiovascular death occurred in 561 pharmacologic MPI and 102 arm exercise participants. Multivariate-adjusted cardiovascular mortality was predicted by arm exercise resting metabolic equivalents (hazard ratio [HR] 0.52, 95% CI 0.39-0.69, P < .001), 1-minute heart rate recovery (HR 0.61, 95% CI 0.44-0.86, P < .001), and pharmacologic and arm exercise delta (peak-rest) heart rate (both P < .001). Only an abnormal arm exercise MPI prognosticated cardiovascular death by multivariate Cox analysis (HR 1.98, 95% CI 1.04-3.77, P < .05). Arm exercise MPI defect number, type, and size provided IDI over covariates for prediction of cardiovascular mortality (IDI = 0.074-0.097). Only pharmacologic defect size prognosticated cardiovascular mortality (IDI = 0.022). Arm exercise capacity, heart rate recovery, and pharmacologic and arm exercise heart rate responses are robust predictors of cardiovascular mortality. Arm exercise MPI results are equivalent and possibly superior to pharmacologic MPI for cardiovascular mortality prediction in patients unable to perform treadmill exercise. Published by Elsevier Inc.

The effect of exercise mode and intensity of sub-maximal physical activities on salivary testosterone to cortisol ratio and α-amylase in young active males

PubMed Central

AZARBAYJANI, MOHAMMAD ALI; FATOLAHI, HOSEYN; RASAEE, MOHAMMAD JAVAD; PEERI, MAGHSOD; BABAEI, ROHOLAH

2011-01-01

We examined the effect of exercise intensity and mode on the acute responses of free testosterone to cortisol ratio and salivary α-amylase. We also evaluated the relationship between cortisol and salivary α-amylase. Ten healthy young active males participated voluntarily in this study in six single sessions. They exercised on a cycle ergo meter, treadmill, and elliptical instrument at intensities of 70% and 85% maximum heart rate for 25 minutes. Saliva samples were collected 5 minutes before and 5 minutes after each exercise session. No significant changes were observed for cortisol. Free testosterone to cortisol ratio increased during each exercise session (F5, 45=3.15, P=0.02). However, these changes are only significant after exercise on the treadmill at 70% maximum heart rate (t=2.94, P=0.02) and 85% maximum heart rate (t=0.53, P=0.03). Salivary α-amylase significantly varied among exercise sessions (F5, 45=3.97, P=0.005), and a significant decline was observed after exercise on the elliptical instrument (t=2.38, P=0.04) and treadmill (t=3.55, P=0.006) at 85% maximum heart rate. We found that the free testosterone to cortisol ratio is dependent on the exercise mode, while the salivary α-amylase response is dependent on the intensity of exercise. The increase of free testosterone to cortisol ratio in this study may indicate lower physiological stress in response to performing these exercises. Applying muscular strength with moderate intensity weight-bearing exercises possibly activates the anabolic pathways. Although the cortisol and salivary α-amylase responses were opposite in the majority of the exercise sessions, no significant inverse relationship was observed. PMID:27182369

The effect of exercise mode and intensity of sub-maximal physical activities on salivary testosterone to cortisol ratio and α-amylase in young active males.

PubMed

Azarbayjani, Mohammad Ali; Fatolahi, Hoseyn; Rasaee, Mohammad Javad; Peeri, Maghsod; Babaei, Roholah

We examined the effect of exercise intensity and mode on the acute responses of free testosterone to cortisol ratio and salivary α-amylase. We also evaluated the relationship between cortisol and salivary α-amylase. Ten healthy young active males participated voluntarily in this study in six single sessions. They exercised on a cycle ergo meter, treadmill, and elliptical instrument at intensities of 70% and 85% maximum heart rate for 25 minutes. Saliva samples were collected 5 minutes before and 5 minutes after each exercise session. No significant changes were observed for cortisol. Free testosterone to cortisol ratio increased during each exercise session (F 5, 45 =3.15, P=0.02) . However, these changes are only significant after exercise on the treadmill at 70% maximum heart rate ( t=2.94, P=0.02 ) and 85% maximum heart rate ( t=0.53, P=0.03 ). Salivary α-amylase significantly varied among exercise sessions (F 5, 45 =3.97, P=0.005), and a significant decline was observed after exercise on the elliptical instrument (t=2.38, P=0.04) and treadmill ( t=3.55, P=0.006 ) at 85% maximum heart rate. We found that the free testosterone to cortisol ratio is dependent on the exercise mode, while the salivary α-amylase response is dependent on the intensity of exercise. The increase of free testosterone to cortisol ratio in this study may indicate lower physiological stress in response to performing these exercises. Applying muscular strength with moderate intensity weight-bearing exercises possibly activates the anabolic pathways. Although the cortisol and salivary α-amylase responses were opposite in the majority of the exercise sessions, no significant inverse relationship was observed.

Eating and Exercise

MedlinePlus

... or drinking carbohydrates before exercise can improve workout performance and may allow you to work out for a longer duration or higher intensity. ... on which pre- and post-exercise eating habits work best for you. Consider keeping a journal to monitor how ... Kenney WL, et al. Body composition and nutrition ...

Effects of respirators under heat/work conditions

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

James, R.; Dukes-Dobos, F.; Smith, R.

Physiological responses and perceived strain of five unacclimatized male subjects were studied. The subjects were exposed to heat during an exercise task and were evaluated while wearing half and full facepiece, cartridge-type, air-purifying respirators, and without a respirator. The exercise consisted of walking on a treadmill for a period of 1 hour in a controlled environmental chamber at each of two different energy expenditure levels (200 and 400 kcal/hr)(approx. = 58 and 116 Watts) and two different heat exposures (air temperatures of 25/sup 0/C and 43.3./sup 0/C). The results indicated that wearing a full facepiece respirator imposed significant physiological strainmore » added to that caused by the heat and workloads used in the study. Five of the six physiological measures show this increased physiological strain: (1) heart rate; (2) minute ventilation; (3) oxygen consumption; (4) energy expenditure; and (5) oral temperature. There was no detectable effect on sweat rate. Although subjective ratings indicated more discomfort with increasing physiological strain, the observed correlations between such measures were low (T/sub b/ < .60). The net consequence of the significant effects indicates that workers' tolerance to moderate or high levels of work under hot conditions while wearing a respirator is reduced. The reduction is more pronounced when wearing a full mask than when wearing a half mask. Changes in respirator design which minimize respiratory dead space are suggested to alleviate this problem. Otherwise, prevention of excessive physiological strain from respirator use when working at moderate or higher levels at hot job sites could necessitate more rest breaks or limiting work time under such conditions.« less

Exercise and sleep predict personal resources in employees' daily lives.

PubMed

Nägel, Inga J; Sonnentag, Sabine

2013-11-01

The present study investigates the interaction of exercise and sleep on state-like personal resources in employees' daily lives. Further, the study examines the association between state-like personal resources and emotional exhaustion. We conducted a diary study over five consecutive working days (total of 443 days) with 144 employees who answered daily online surveys after work and before bedtime. Multilevel modeling showed that exercise after work was positively related to the next day's personal resources when sleep duration during the night time was longer compared to other nights. Furthermore, personal resources positively related to lower emotional exhaustion after work on the next day. This study demonstrates that exercise and sleep may help to renew personal resources. Results stress the importance of balancing exercise and sleep in daily life. © 2013 The International Association of Applied Psychology.

Biochemical and physiological parameters and estimated work output in draught horses pulling loads for long periods.

PubMed

Perez, R; Recabarren, S E; Valdes, P; Hetz, E

1992-01-01

A study was undertaken in five draught horses of 648 +/- 33 kg body weight to find the effects of continuously pulling loads on their cardiovascular, respiratory and metabolic responses. A cart equipped with an odometer, for measuring distance, and a hydraulic dynamometer, for measuring draught force, was used. Heart and respiration rates and rectal temperatures were recorded. Blood samples for measuring arterial and venous pH and blood gases, haemoglobin, glucose and lactic acid concentrations and the serum activity of the enzymes creatine phosphokinase (CK), lactate dehydrogenase, aspartate aminotransferase and alkaline phosphatase were taken before exercise and immediately after each journey (morning and afternoon) of the daily work. Draught exercise, with loads which generated forces of between 0.57 and 0.59 kN, at speeds of 1.60 to 2.11 m/s, for 8 h daily for five consecutive days, with resting intervals of 10 min each hour, was well tolerated. Exercise tolerance was evaluated from the recovery from the changes observed in the biochemical and physiological parameters induced by the work. The analysis of these showed that, when the horses were subjected to prolonged periods of resting, their loss of fitness for work was shown by significant increases in the serum activity of muscle-derived enzymes and in blood lactate concentrations during the first day of work. However, over the following days the horses adapted to the work, so that the decreases in serum enzyme activities and blood lactate concentrations were reduced. Since similar observations have been described for racehorses, the determination of blood lactate concentrations and the serum activities of muscle-derived enzymes, specifically CK, seem to be good indicators of fitness in draught horses.

Physical activity and cancer prevention : pathways and targets for intervention.

PubMed

Rogers, Connie J; Colbert, Lisa H; Greiner, John W; Perkins, Susan N; Hursting, Stephen D

2008-01-01

The prevalence of obesity, an established epidemiological risk factor for many cancers, has risen steadily for the past several decades in the US and many other countries. Particularly alarming are the increasing rates of obesity among children, portending continuing increases in the rates of obesity and obesity-related cancers for many years to come. Modulation of energy balance, via increased physical activity, has been shown in numerous comprehensive epidemiological reviews to reduce cancer risk. Unfortunately, the effects and mechanistic targets of physical activity interventions on the carcinogenesis process have not been thoroughly characterized. Studies to date suggest that exercise can exert its cancer-preventive effects at many stages during the process of carcinogenesis, including both tumour initiation and progression. As discussed in this review, exercise may be altering tumour initiation events by modifying carcinogen activation, specifically by enhancing the cytochrome P450 system and by enhancing selective enzymes in the carcinogen detoxification pathway, including, but not limited to, glutathione-S-transferases. Furthermore, exercise may reduce oxidative damage by increasing a variety of anti-oxidant enzymes, enhancing DNA repair systems and improving intracellular protein repair systems. In addition to altering processes related to tumour initiation, exercise may also exert a cancer-preventive effect by dampening the processes involved in the promotion and progression stages of carcinogenesis, including scavenging reactive oxygen species (ROS); altering cell proliferation, apoptosis and differentiation; decreasing inflammation; enhancing immune function; and suppressing angiogenesis. A paucity of data exists as to whether exercise may be working as an anti-promotion strategy via altering ROS in initiated or preneoplastic models; therefore, no conclusions can be made about this possible mechanism. The studies directly examining cell proliferation and apoptosis have shown that exercise can enhance both processes, which is difficult to interpret in the context of carcinogenesis. Studies examining the relationship between exercise and chronic inflammation suggest that exercise may reduce pro-inflammatory mediators and reduce the state of low-grade, chronic inflammation. Additionally, exercise has been shown to enhance components of the innate immune response (i.e. macrophage and natural killer cell function). Finally, only a limited number of studies have explored the relationship between exercise and angiogenesis; therefore, no conclusions can be made currently about the role of exercise in the angiogenesis process as it relates to tumour progression. In summary, exercise can alter biological processes that contribute to both anti-initiation and anti-progression events in the carcinogenesis process. However, more sophisticated, detailed studies are needed to examine each of the potential mechanisms contributing to an exercise-induced decrease in carcinogenesis in order to determine the minimum dose, duration and frequency of exercise needed to yield significant cancer-preventive effects, and whether exercise can be used prescriptively to reverse the obesity-induced physiological changes that increase cancer risk.

Exercise and Physical Fitness: MedlinePlus Health Topic

MedlinePlus

... Learn to love exercise Make time to move Outdoor fitness routine Physical activity Working with a personal trainer Yoga for health Show More Show Less Related Health Topics Benefits of Exercise Exercise for Children Exercise for Seniors ...

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.

Assessment and exercise in low back pain. With special reference to the management of pain and disability following first time lumbar disc surgery.

PubMed

Manniche, C

1995-09-01

Eight articles including 555 low back pain patients have been published. They included the following topics: 1) A ratio interval rating scale (Low Back Pain Rating Scale (RS)) was introduced. The possibility of registering the actual status in low back pain patients including; Back Pain, Sciatica, Functional Disability and Physical Impairment was studied. Methods of evaluating index-scales developed in the field of psychometry were applied in the validation process of RS. RS was found to be both valid and user friendly. 2) Using Low Back Pain Rating Scale the general outcome following first-time lumbar disc surgery was analysed through a survey. The results showed that more than half of the patients still suffered from considerable Back Pain, Sciatica, and Functional Disabilities. Approximately 25% of the patients risked reduced work capabilities, and many receive pensions. 3) By means of a comprehensive statistical analysis of 18 studied preoperative demographic and physical findings, sex, hypoalgesia, smoking and Finneson-index were found to have prognostic value. 4) Attempts at influencing the results obtained from lumbar disc surgery have been tested in 3 randomized trials, including back training and peroperative glucocorticoid administration. 5) Three randomized trials including patients suffering from chronic low back pain (with or without previous lumbar disc surgery) attempted to convey which elements of a training programme provide patients with the greatest effect and the least risk of side-effects. It was concluded that Low Back Pain Rating Scale is a useable assessment instrument in both clinical trials and as a daily quality control instrument of back patients. There is a need of increased patient scrutiny in patient selection prior to lumbar disc surgery. Postoperative rehabilitation should include intensive back training, which has been shown to be of value in behavioural support and restoration of functional deficits. This has resulted in increased work capacities for disc operated patients. The exercise programmes are generally free of side-effects. As regards chronic back pain patients with or without previous lumbar surgery, high dosage exercises with training periods lasting at least 12 to 16 sessions are of crucial importance for success. Exercises should be dynamic and full-range, and carried out following the adage "Don't let the pain be your guide.

Periosteal Electrical Dry Needling as an Adjunct to Exercise and Manual Therapy for Knee Osteoarthritis: A Multi-Center Randomized Clinical Trial.

PubMed

Dunning, James; Butts, Raymond; Young, Ian; Mourad, Firas; Galante, Victoria; Bliton, Paul; Tanner, Michelle; Fernández-de-Las-Peñas, César

2018-05-28

To compare the effects of adding electrical dry needling into a manual therapy and exercise program on pain, stiffness, function, and disability in individuals with painful knee osteoarthritis (OA). Two hundred and forty-two participants (n=242) with painful knee OA were randomized to receive 6 weeks of electrical dry needling, manual therapy and exercise (n=121) or manual therapy and exercise (n=121). The primary outcome was related-disability as assessed by the Western Ontario and McMaster Universities (WOMAC) Osteoarthritis Index at 3 months. Individuals receiving the combination of electrical dry needling, manual therapy and exercise experienced significantly greater improvements in related-disability (WOMAC: F=35.504; P<0.001) than those receiving manual therapy and exercise alone at 6 weeks and 3 months. Patients receiving electrical dry needling were 1.7 times more likely to have completely stopped taking medication for their pain at 3 months than individuals receiving manual therapy and exercise (OR: 1.6; 95%CI: 1.24-2.01; P=0.001). Based on the cutoff score of +5 on the Global Rating of Change (GROC), significantly (X =14.887; P<0.001) more patients (n=91, 75%) within the dry needling group achieved a successful outcome compared to the manual therapy and exercise group (n=22, 18%) at 3 months. Effect sizes were large (SMD>0.82) for all outcome measures in favor of the electrical dry needling group at 3 months. The inclusion of electrical dry needling into a manual therapy and exercise program was more effective for improving pain, function and related-disability than the application of manual therapy and exercise alone in individuals with painful knee OA. Therapy, Level 1b. Prospectively registered February 10, 2015 on http://www.clinicaltrials.gov (NCT02373631)This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal. http://creativecommons.org/licenses/by-nc-nd/4.0/.

Changes in force, surface and motor unit EMG during post-exercise development of low frequency fatigue in vastus lateralis muscle.

PubMed

de Ruiter, C J; Elzinga, M J H; Verdijk, P W L; van Mechelen, W; de Haan, A

2005-08-01

We investigated the effects of low frequency fatigue (LFF) on post-exercise changes in rectified surface EMG (rsEMG) and single motor unit EMG (smuEMG) in vastus lateralis muscle (n = 9). On two experimental days the knee extensors were fatigued with a 60-s-isometric contraction (exercise) at 50% maximal force capacity (MFC). On the first day post-exercise (15 s, 3, 9, 15, 21 and 27 min) rsEMG and electrically-induced (surface stimulation) forces were investigated. SmuEMG was obtained on day two. During short ramp and hold (5 s) contractions at 50% MFC, motor unit discharges of the same units were followed over time. Post-exercise MFC and tetanic force (100 Hz stimulation) recovered to about 90% of the pre-exercise values, but recovery with 20 Hz stimulation was less complete: the 20-100 Hz force ratio (mean +/- SD) decreased from 0.65+/-0.06 (pre-exercise) to 0.56+/-0.04 at 27 min post-exercise (P<0.05), indicative of LFF. At 50% MFC, pre-exercise rsEMG (% pre-exercise maximum) and motor unit discharge rate were 51.1 +/- 12.7% and 14.1 +/- 3.7 (pulses per second; pps) respectively, 15 s post-exercise the respective values were 61.4 +/- 15.4% (P<0.05) and 13.2 +/- 5.6 pps (P>0.05). Thereafter, rsEMG (at 50% MFC) remained stable but motor unit discharge rate significantly increased to 17.7 +/- 3.9 pps 27 min post-exercise. The recruitment threshold decreased (P<0.05) from 27.7 +/- 6.6% MFC before exercise to 25.2 +/- 6.7% 27 min post-exercise. The increase in discharge rate was significantly greater than could be expected from the decrease in recruitment threshold. Thus, post-exercise LFF was compensated by increased motor unit discharge rates which could only partly be accounted for by the small decrease in motor unit recruitment threshold.

Inducible laryngeal obstruction during exercise: moving beyond vocal cords with new insights.

PubMed

Olin, James Tod; Clary, Matthew S; Deardorff, Emily H; Johnston, Kristina; Morris, Michael J; Sokoya, Mofiyinfolu; Staudenmayer, Herman; Christopher, Kent L

2015-02-01

Exercise as an important part of life for the health and wellness of children and adults. Inducible laryngeal obstruction (ILO) is a consensus term used to describe a group of disorders previously called vocal cord dysfunction, paradoxical vocal fold motion, and numerous other terms. Exercise-ILO can impair one's ability to exercise, can be confused with asthma, leading to unnecessary prescription of asthma controller and rescue medication, and results in increased healthcare resource utilization including (rarely) emergency care. It is characterized by episodic shortness of breath and noisy breathing that generally occurs at high work rates. The present diagnostic gold standard for all types of ILO is laryngoscopic visualization of inappropriate glottic or supraglottic movement resulting in airway narrowing during a spontaneous event or provocation challenge. A number of different behavioral techniques, including speech therapy, biofeedback, and cognitive-behavioral psychotherapy, may be appropriate to treat individual patients. A consensus nomenclature, which will allow for better characterization of patients, coupled with new diagnostic techniques, may further define the epidemiology and etiology of ILO as well as enable objective evaluation of therapeutic modalities.

A novel simulation model for minimally invasive spine surgery.

PubMed

Walker, James B; Perkins, Eddie; Harkey, H Louis

2009-12-01

Minimally invasive spine surgery (MISS) is among the fastest growing technologies in general neurosurgical practice. In addition, great demand exists to teach these skills to neurosurgery residents. With newly enforced work hour restrictions, opportunities to acquire these skills are limited, necessitating development of alternative strategies of education. We describe a novel simulation model for MISS supplemented by resident self-assessment analysis and evaluation. The simulator was constructed using a nontransparent Plexiglas frame supplemented with a modified halo frame on which to affix spine specimens. Interchangeable copper tubing was affixed to a 360-degree pivot system to replicate a working portal. Deer skulls and spines were then collected and prepared accordingly. Laboratory exercises were based on the resident's level of training with emphasis on proper drilling techniques. Eight neurosurgery residents were asked to complete the exercises and complete a self-assessment survey regarding their competence level on a scale of 0 to 5, both before and after completing the skill sets. Additionally, they were asked to complete an exit survey that was used to assess the simulation exercises. All exercises were completed successfully with the exception of placing 2 separate pedicle screws through the same portal, which posed difficulty on some specimens because of the of lack of lordosis of the specimens, leading to unfavorable trajectories using a free-hand technique. With regard to the resident self-assessment analysis, the mean confidence rating for performing an MISS laminectomy improved by a difference of 1.25 points (n = 8; 95% confidence interval, 0.66-1.84; P = 0.0015), from 2.50 to 3.75 before and after simulation exercises, respectively, and reached statistical significance. For the senior-level residents, the mean confidence rating for performing MISS placement of pedicle screws using a free-hand technique improved by a difference of 1.00 (n = 3; 95% confidence interval, -1.48-3.48; P = 0.225), from 3.33 to 4.33 before and after simulation exercises, respectively. Results of the exit survey were encouraging. The MISS simulator is a feasible, inexpensive, and reproducible adjunct to neurosurgery resident training and provides a new teaching method for spine surgery. Further investigation of this technology is warranted, although multicenter, randomized, controlled trials assessing its validity may not be practical because of ethical constraints with regard to patient safety.

Potentially conflicting metabolic demands of diving and exercise in seals.

PubMed

Castellini, M A; Murphy, B J; Fedak, M; Ronald, K; Gofton, N; Hochachka, P W

1985-02-01

Metabolic replacement rates (Ra) for glucose and free fatty acids (FFA) were determined during rest, exercise, and diving conditions in the gray seal using bolus injections of radiotracers. In the exercise experiments the seal swam at a metabolic rate elevated twofold over resting Ra for glucose and FFA while resting were similar to values found in terrestrial mammals and other marine mammal species. During exercise periods glucose turnover increased slightly while FFA turnover changes were variable. However, the energetic demands of exercise could not be met by the increase in the replacement rates of glucose or FFA even if both were completely oxidized. Under diving conditions the tracer pool displayed radically different specific activity curves indicative of the changes in perfusion and metabolic rate associated with a strong dive response. Since the radiotracer curves during exercise and diving differed qualitatively and quantitatively, it is possible that similar studies on freely diving animals can be used to assess the role of the diving response during underwater swimming in nature.

Operational Implementation of a 2-Hour Prebreathe Protocol for International Space Station

NASA Technical Reports Server (NTRS)

Waligora, James M.; Conkin, J.; Foster, P. P.; Schneider, S.; Loftin, Karin C.; Gernhardt, Michael L.; Vann, R.

2000-01-01

Procedures, equipment, and analytical techniques were developed to implement the ground tested 2-hour protocol in-flight operations. The methods are: 1) The flight protocol incorporates additional safety margin over the ground tested protocol. This includes up to 20 min of additional time on enriched O2 during suit purge and pressure check, increased duration of extravehicular activity (EVA) preparation exercise during O2 prebreathing (up to 90 min vs; the tested 24 min), and reduced rates of depressurization. The ground test observations were combined with model projections of the conservative measures (using statistical models from Duke University and NASA JSQ to bound the risk of Type I and Type II decompression sickness (DCS). 2) An inflight exercise device using the in-flight ergometer and elastic tubes for upper body exercise was developed to replicate the dual cycle exercise in the ground trials. 3) A new in-flight breathing system was developed and man-tested. 4) A process to monitor inflight experience with the protocol, including the use of an in-suit Doppler bubble monitor when available, was developed. The results are: 1) The model projections of the conservative factors of the operational protocol were shown to reduce the risk of DCS to levels consistent with the observations of no DCS to date in the shuttle program. 2) Cross over trials of the dual cycle ergometer used in ground tests and the in-flight exercise system verified that02consumption and the % division of work between upper and lower body was not significantly different at the p= 0.05 level. 3) The in-flight breathing system was demonstrated to support work rates generating 75% O2(max) in 95 percentile subjects. 4) An in-flight monitoring plan with acceptance criteria was put in place for the 2-hour prebreathe protocol. And the conclusions are: The 2-hour protocol has been approved for flight, and all implementation efforts are in place to allow use of the protocol as early as flight ISS 7A, now scheduled in November of 2000.

Magnetic resonance spectroscopy in congenital heart disease.

PubMed Central

Miall-Allen, V. M.; Kemp, G. J.; Rajagopalan, B.; Taylor, D. J.; Radda, G. K.; Haworth, S. G.

1996-01-01

OBJECTIVE: To determine the feasibility of studying myocardial and skeletal muscle bioenergetics using 31P magnetic resonance spectroscopy (MRS) in babies and young children with congenital heart disease. SUBJECTS: 16 control subjects aged 5 months to 24 years and 18 patients with CHD, aged 7 months to 23 years, of whom 11 had cyanotic CHD, five had cardiac failure, and two had had a Senning procedure. DESIGN: 31P MRS was carried out using a 1.9 Tesla horizontal 65 cm bore whole body magnet to study the myocardium in 10 patients and skeletal muscle (gastrocnemius) in 14 patients, eight of whom were exercised, together with appropriate controls. RESULTS: In hypoxaemic patients, in skeletal muscle at rest intracellular pH (pHi) was abnormally high [7.06 (SEM 0.04) v 7.04 (0.05), P < 0.01] and showed a positive correlation with haemoglobin (P < 0.03). On exercise, hypoxaemic patients fatigued more quickly but end-exercise pHi and phosphocreatine recovery were normal, implying that an equivalent but smaller amount of work had been performed. End-exercise ADP concentration was lower. On recovery, the initial rate of phosphocreatine resynthesis was low. Skeletal muscle bioenergetics were within normal limits in those in heart failure. In the myocardium, the phosphocreatine/ATP ratio was similar in controls and hypoxaemic subjects, but low in those in heart failure. CONCLUSIONS: In heart failure, the myocardial phosphocreatine/ATP ratio was reduced, as in adults, while resting skeletal muscle studies were normal. By contrast, hypoxaemic children had normal myocardial bioenergetics, but showed skeletal muscle alkalinity, and energy reserves were more readily depleted on exercise. On recovery, the initially slow phosphocreatine resynthesis rate reflects a low rate of mitochondrial ATP synthesis, probably due to an inadequate oxygen supply. 31P MRS offers a safe, non-invasive method of studying myocardial and skeletal muscle bioenergetics in children as young as 5 months. PMID:8697167

Physiological measures in participants with chronic fatigue syndrome, multiple sclerosis and healthy controls following repeated exercise: a pilot study.

PubMed

Hodges, L D; Nielsen, T; Baken, D

2017-08-07

To compare physiological responses of chronic fatigue syndrome (CFS/ME), multiple sclerosis (MS) and healthy controls (HC) following a 24-h repeated exercise test. Ten CFS, seven MS and 17 age- and gender-matched healthy controls (10, CFS HC; and seven, MS HC) were recruited. Each participant completed a maximal incremental cycle exercise test on day 1 and again 24 h later. Heart rate (HR), blood pressure (BP), rating of perceived exertion (RPE), oxygen consumption (V˙O2), carbon dioxide production and workload (WL) were recorded. Data analysis investigated these responses at anaerobic threshold (AT) and peak work rate (PWR). On day 2, both CFS and MS had significantly reduced max workload compared to HC. On day 2, significant differences were apparent in WL between CFS and CFS HC (93 ± 37 W, 132 ± 42 W, P<0·042). CFS workload decreased on day 2, alongside a decrease in HR but with an increase in V˙O2 (ml   kg   min -1 ). This was in comparison with an increase in WL, HR and V˙O2 for CFS HC. MS demonstrated a decreased WL compared to MS HC on both days of the study (D1 81 ± 30 W, 116 ±30 W; D2 84 ± 29 W, 118 ± 36 W); however, patients with MS were able to achieve a higher WL on day 2 alongside MS HC. These results suggest that exercise exhibits a different physiological response in MS and CFS/ME, demonstrating repeated cardiovascular exercise testing as a valid measure for differentiating between fatigue conditions. © 2017 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

Advancing non-directive pregnancy options counseling skills: A pilot Study on the use of blended learning with an online module and simulation.

PubMed

Lupi, Carla; Ward-Peterson, Melissa; Chang, Winnie

2016-10-01

Limitations on didactic time pose barriers to teaching non-directive pregnancy options counseling. This study set out to explore the use of an online module to support trainee performance in a pregnancy options counseling standardized-patient exercise implemented among third-year medical students, and to examine the effect of clinical experience on student performance. An online module was developed. A convenience sample of forty-six student performances in a family medicine clerkship participated in a standardized patient exercise. Trained faculty rated performances. Students completed a self-assessment and provided feedback on the online module. Chi-square and Mann-Whitney-U tests were used to analyze data. Three coders qualitatively examined narrative student comments. Thirty-four students passed, 11 achieved a minimal pass, and one failed. The mean global rating from faculty was 2.8 (pass). Students with prior clinical experience significantly outperformed those without on the global rating scale with mean scores of 3.1 compared to 2.7, respectively (p=.044). All students agreed that the online module helped prepare them for the exercise. Qualitative analysis of students' feedback on the module revealed strengths in content and pedagogy. In their self-assessments, all but two students referred to content explicitly conveyed in the module. All students agreed that an online module supported their performance of non-directive pregnancy options counseling skills. Prior clinical experience was associated with improved performance. This module, along with the simulated exercise, can be implemented as a blended learning exercise without additional faculty teaching effort in standardized patient resource centers. Students agreed that an online module facilitates simulated performance of non-directive pregnancy options counseling skills. Future work should compare the impact of this approach to others, and explore the additional training needed to maintain and build on initial learning. Copyright © 2016 Elsevier Inc. All rights reserved.

Skeletal muscle fatigue precedes the slow component of oxygen uptake kinetics during exercise in humans.

PubMed

Cannon, Daniel T; White, Ailish C; Andriano, Melina F; Kolkhorst, Fred W; Rossiter, Harry B

2011-02-01

The mechanisms determining exercise intolerance are poorly understood. A reduction in work efficiency in the form of an additional energy cost and oxygen requirement occurs during high-intensity exercise and contributes to exercise limitation. Muscle fatigue and subsequent recruitment of poorly efficient muscle fibres has been proposed to mediate this decline. These data demonstrate in humans, that muscle fatigue, generated in the initial minutes of exercise, is correlated with the increasing energy demands of high-intensity exercise. Surprisingly, however, while muscle fatigue reached a plateau, oxygen uptake continued to increase throughout 8 min of exercise. This suggests that additional recruitment of inefficient muscle fibres may not be the sole mechanism contributing to the decline in work efficiency during high-intensity exercise.

The Effects of a Ketogenic Diet on Exercise Metabolism and Physical Performance in Off-Road Cyclists

PubMed Central

Zajac, Adam; Poprzecki, Stanisław; Maszczyk, Adam; Czuba, Miłosz; Michalczyk, Małgorzata; Zydek, Grzegorz

2014-01-01

The main objective of this research was to determine the effects of a long-term ketogenic diet, rich in polyunsaturated fatty acids, on aerobic performance and exercise metabolism in off-road cyclists. Additionally, the effects of this diet on body mass and body composition were evaluated, as well as those that occurred in the lipid and lipoprotein profiles due to the dietary intervention. The research material included eight male subjects, aged 28.3 ± 3.9 years, with at least five years of training experience that competed in off-road cycling. Each cyclist performed a continuous exercise protocol on a cycloergometer with varied intensity, after a mixed and ketogenic diet in a crossover design. The ketogenic diet stimulated favorable changes in body mass and body composition, as well as in the lipid and lipoprotein profiles. Important findings of the present study include a significant increase in the relative values of maximal oxygen uptake (VO2max) and oxygen uptake at lactate threshold (VO2 LT) after the ketogenic diet, which can be explained by reductions in body mass and fat mass and/or the greater oxygen uptake necessary to obtain the same energy yield as on a mixed diet, due to increased fat oxidation or by enhanced sympathetic activation. The max work load and the work load at lactate threshold were significantly higher after the mixed diet. The values of the respiratory exchange ratio (RER) were significantly lower at rest and during particular stages of the exercise protocol following the ketogenic diet. The heart rate (HR) and oxygen uptake were significantly higher at rest and during the first three stages of exercise after the ketogenic diet, while the reverse was true during the last stage of the exercise protocol conducted with maximal intensity. Creatine kinase (CK) and lactate dehydrogenase (LDH) activity were significantly lower at rest and during particular stages of the 105-min exercise protocol following the low carbohydrate ketogenic diet. The alterations in insulin and cortisol concentrations due to the dietary intervention confirm the concept that the glucostatic mechanism controls the hormonal and metabolic responses to exercise. PMID:24979615

The effects of a ketogenic diet on exercise metabolism and physical performance in off-road cyclists.

PubMed

Zajac, Adam; Poprzecki, Stanisław; Maszczyk, Adam; Czuba, Miłosz; Michalczyk, Małgorzata; Zydek, Grzegorz

2014-06-27

The main objective of this research was to determine the effects of a long-term ketogenic diet, rich in polyunsaturated fatty acids, on aerobic performance and exercise metabolism in off-road cyclists. Additionally, the effects of this diet on body mass and body composition were evaluated, as well as those that occurred in the lipid and lipoprotein profiles due to the dietary intervention. The research material included eight male subjects, aged 28.3 ± 3.9 years, with at least five years of training experience that competed in off-road cycling. Each cyclist performed a continuous exercise protocol on a cycloergometer with varied intensity, after a mixed and ketogenic diet in a crossover design. The ketogenic diet stimulated favorable changes in body mass and body composition, as well as in the lipid and lipoprotein profiles. Important findings of the present study include a significant increase in the relative values of maximal oxygen uptake (VO2max) and oxygen uptake at lactate threshold (VO2 LT) after the ketogenic diet, which can be explained by reductions in body mass and fat mass and/or the greater oxygen uptake necessary to obtain the same energy yield as on a mixed diet, due to increased fat oxidation or by enhanced sympathetic activation. The max work load and the work load at lactate threshold were significantly higher after the mixed diet. The values of the respiratory exchange ratio (RER) were significantly lower at rest and during particular stages of the exercise protocol following the ketogenic diet. The heart rate (HR) and oxygen uptake were significantly higher at rest and during the first three stages of exercise after the ketogenic diet, while the reverse was true during the last stage of the exercise protocol conducted with maximal intensity. Creatine kinase (CK) and lactate dehydrogenase (LDH) activity were significantly lower at rest and during particular stages of the 105-min exercise protocol following the low carbohydrate ketogenic diet. The alterations in insulin and cortisol concentrations due to the dietary intervention confirm the concept that the glucostatic mechanism controls the hormonal and metabolic responses to exercise.

Automatic Evaluations and Exercising: Systematic Review and Implications for Future Research.

PubMed

Schinkoeth, Michaela; Antoniewicz, Franziska

2017-01-01

The general purpose of this systematic review was to summarize, structure and evaluate the findings on automatic evaluations of exercising. Studies were eligible for inclusion if they reported measuring automatic evaluations of exercising with an implicit measure and assessed some kind of exercise variable. Fourteen nonexperimental and six experimental studies (out of a total N = 1,928) were identified and rated by two independent reviewers. The main study characteristics were extracted and the grade of evidence for each study evaluated. First, results revealed a large heterogeneity in the applied measures to assess automatic evaluations of exercising and the exercise variables. Generally, small to large-sized significant relations between automatic evaluations of exercising and exercise variables were identified in the vast majority of studies. The review offers a systematization of the various examined exercise variables and prompts to differentiate more carefully between actually observed exercise behavior (proximal exercise indicator) and associated physiological or psychological variables (distal exercise indicator). Second, a lack of transparent reported reflections on the differing theoretical basis leading to the use of specific implicit measures was observed. Implicit measures should be applied purposefully, taking into consideration the individual advantages or disadvantages of the measures. Third, 12 studies were rated as providing first-grade evidence (lowest grade of evidence), five represent second-grade and three were rated as third-grade evidence. There is a dramatic lack of experimental studies, which are essential for illustrating the cause-effect relation between automatic evaluations of exercising and exercise and investigating under which conditions automatic evaluations of exercising influence behavior. Conclusions about the necessity of exercise interventions targeted at the alteration of automatic evaluations of exercising should therefore not be drawn too hastily.

Automatic Evaluations and Exercising: Systematic Review and Implications for Future Research

PubMed Central

Schinkoeth, Michaela; Antoniewicz, Franziska

2017-01-01

The general purpose of this systematic review was to summarize, structure and evaluate the findings on automatic evaluations of exercising. Studies were eligible for inclusion if they reported measuring automatic evaluations of exercising with an implicit measure and assessed some kind of exercise variable. Fourteen nonexperimental and six experimental studies (out of a total N = 1,928) were identified and rated by two independent reviewers. The main study characteristics were extracted and the grade of evidence for each study evaluated. First, results revealed a large heterogeneity in the applied measures to assess automatic evaluations of exercising and the exercise variables. Generally, small to large-sized significant relations between automatic evaluations of exercising and exercise variables were identified in the vast majority of studies. The review offers a systematization of the various examined exercise variables and prompts to differentiate more carefully between actually observed exercise behavior (proximal exercise indicator) and associated physiological or psychological variables (distal exercise indicator). Second, a lack of transparent reported reflections on the differing theoretical basis leading to the use of specific implicit measures was observed. Implicit measures should be applied purposefully, taking into consideration the individual advantages or disadvantages of the measures. Third, 12 studies were rated as providing first-grade evidence (lowest grade of evidence), five represent second-grade and three were rated as third-grade evidence. There is a dramatic lack of experimental studies, which are essential for illustrating the cause-effect relation between automatic evaluations of exercising and exercise and investigating under which conditions automatic evaluations of exercising influence behavior. Conclusions about the necessity of exercise interventions targeted at the alteration of automatic evaluations of exercising should therefore not be drawn too hastily. PMID:29250022

The Acute Effects of Aerobic Exercise on Cognitive Flexibility and Task-Related Heart Rate Variability in Children With ADHD and Healthy Controls.

PubMed

Ludyga, Sebastian; Gerber, Markus; Mücke, Manuel; Brand, Serge; Weber, Peter; Brotzmann, Mark; Pühse, Uwe

2018-02-01

To investigate cognitive flexibility and task-related heart rate variability following moderately intense aerobic exercise and after watching a video in both children with ADHD and healthy controls. Using a cross-over design, participants completed cognitive assessments following exercise and a physically inactive control condition. Behavioral performance was assessed using the Alternate Uses task. Heart rate variability was recorded via electrocardiography during the cognitive task. The statistical analysis revealed that in comparison with the control condition, both groups showed higher cognitive flexibility following aerobic exercise. Moreover, decreased low frequency and high frequency power was observed in the exercise condition. The findings suggest that exercise elicits similar benefits for cognitive flexibility in children with ADHD and healthy controls, partly due to an increase in arousal induced by parasympathetic withdrawal.

Evaluation of left ventricular performance during supine exercise by transoesophageal M-mode echocardiography in normal subjects.

PubMed Central

Matsumoto, M; Hanrath, P; Kremer, P; Tams, C; Langenstein, B A; Schlüter, M; Weiter, R; Bleifeld, W

1982-01-01

In order to evaluate left ventricular function during dynamic exercise transoesophageal M-mode recordings of the left ventricle were carried out with a newly developed transducer gastroscope system. Twelve healthy subjects performed a graded supine bicycle exercise test. Stable and good quality images of the left ventricle at rest and during exercise at different steps up to a maximum workload of 100 watts were obtained in all patients. Isotonic maximum exercise resulted in a significant increase in fractional shortening of the left ventricle, peak shortening rate, and peak lengthening rate of the left ventricular minor axis. Left ventricular end-diastolic dimension decreased significantly. With increasing workload the pressure rate product increased significantly. It is concluded that transoesophageal M-mode echocardiography is a useful method of evaluating left ventricular performance during dynamic exercise. Images PMID:7082515

Effects of 4 month exercise on left ventricular remodeling and autonomic nervous system in hypertensive patients.

PubMed

Zheng, Huan; Xie, Nanzi; Xu, Huifeng; Huang, Junling; Xie, Xiaoyun; Luo, Ming

2016-03-01

We sought to investigate effects of supervised exercise training on left ventricular remodeling, left ventricular function and autonomic nervous system of hypertensive patients without medication. Fifty borderline and mildly hypertensive patients were enrolled and randomly divided into 2 groups (25 in each). Exercise group received a 4 months' exercise program, prescribed according to their first cardiopulmonary exercise tests, while the control group received routine dietary recommendation. All patients underwent noradrenalin assay, cardiopulmonary exercise tests and echocardiographic studies at enrollment and 4 month follow-up. At baseline no statistically difference between the two groups were observed in clinical characteristics, echographic variants or cardiopulmonary test index. Four months later, exercise group showed higher values of VO2peak, Powermax (max workload), AT (anaerobic threshold), VO2AT (VO2 at anaerobic threshold), tAT (time from beginning to anaerobic threshold) and heart rate recovery compared to the control group (P<0.05). Additionally, systolic/diastolic blood pressure decreased significantly in the exercise group compared to the control group (P<0.05). Moreover, there was significant reduction in left ventricular mass index in the exercise group (P<0.01), and there was also an inverse correlation between changes in left ventricular mass index and heart rate recovery (r=-0.52, P<0.01). Four-month exercise training in borderline and mildly hypertensive patients not only decreased their blood pressure levels, but also induced an improvement of exercise capability, left ventricular remodeling and heart rate recovery. Heart rate recovery improvement was significantly associated with decrease of left ventricular mass index, which indicated that favorable adjustment in autonomic nervous system of exercise training might be an important pathway to reverse left ventricular remodeling.

The General Adaptation Syndrome: Potential misapplications to resistance exercise.

PubMed

Buckner, Samuel L; Mouser, J Grant; Dankel, Scott J; Jessee, Matthew B; Mattocks, Kevin T; Loenneke, Jeremy P

2017-11-01

Within the resistance training literature, one of the most commonly cited tenets with respect to exercise programming is the "General Adaptation Syndrome" (GAS). The GAS is cited as a central theory behind the periodization of resistance exercise. However, after examining the original stress research by Hans Selye, the applications of GAS to resistance exercise may not be appropriate. To examine the original work of Hans Selye, as well as the original papers through which the GAS was established as a central theory for periodized resistance exercise. We conducted a review of Selye's work on the GAS, as well as the foundational papers through which this concept was applied to resistance exercise. The work of Hans Selye focused on the universal physiological stress responses noted upon exposure to toxic levels of a variety of pharmacological agents and stimuli. The extrapolations that have been made to resistance exercise appear loosely based on this concept and may not be an appropriate basis for application of the GAS to resistance exercise. Copyright © 2017 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Mechanical ventilatory constraints during incremental cycle exercise in human pregnancy: implications for respiratory sensation

PubMed Central

Jensen, Dennis; Webb, Katherine A; Davies, Gregory A L; O'Donnell, Denis E

2008-01-01

The aim of this study was to identify the physiological mechanisms of exertional respiratory discomfort (breathlessness) in pregnancy by comparing ventilatory (breathing pattern, airway function, operating lung volumes, oesophageal pressure (Poes)-derived indices of respiratory mechanics) and perceptual (breathlessness intensity) responses to incremental cycle exercise in 15 young, healthy women in the third trimester (TM3; between 34 and 38 weeks gestation) and again 4–5 months postpartum (PP). During pregnancy, resting inspiratory capacity (IC) increased (P < 0.01) and end-expiratory lung volume decreased (P < 0.001), with no associated change in total lung capacity (TLC) or static respiratory muscle strength. This permitted greater tidal volume (VT) expansion throughout exercise in TM3, while preserving the relationship between contractile respiratory muscle effort (tidal Poes swing expressed as a percentage of maximum inspiratory pressure (PImax)) and thoracic volume displacement (VT expressed as a percentage of vital capacity) and between breathlessness and ventilation (V̇E). At the highest equivalent work rate (HEWR = 128 ± 5 W) in TM3 compared with PP: V̇E, tidal Poes/PImax and breathlessness intensity ratings increased by 10.2 l min−1 (P < 0.001), 8.8%PImax (P < 0.05) and 0.9 Borg units (P < 0.05), respectively. Pulmonary resistance was not increased at rest or during exercise at the HEWR in TM3, despite marked increases in mean tidal inspiratory and expiratory flow rates, suggesting increased bronchodilatation. Dynamic mechanical constraints on VT expansion (P < 0.05) with associated increased breathlessness intensity ratings (P < 0.05) were observed near peak exercise in TM3 compared with PP. In conclusion: (1) pregnancy-induced increases in exertional breathlessness reflected the normal awareness of increased V̇E and contractile respiratory muscle effort; (2) mechanical adaptations of the respiratory system, including recruitment of resting IC and increased bronchodilatation, accommodated the increased VT while preserving effort–displacement and breathlessness–V̇E relationships; and (3) dynamic mechanical ventilatory constraints contributed to respiratory discomfort near the limits of tolerance in late gestation. PMID:18687714

Exercise Capacity and Selected Physiological Factors by Ancestry and Residential Altitude: Cross-Sectional Studies of 9–10-Year-Old Children in Tibet

PubMed Central

Berntsen, Sveinung; Andersen, Lars Bo; Stigum, Hein; Ouzhuluobu; Nafstad, Per; Wu, Tianyi; Bjertness, Espen

2014-01-01

Abstract Bianba, Sveinung Bernsten, Lars Bo Andersen, Hein Stegum, Ouzhuluobu, Per Nafstad, Tianyi Wu, and Espen Bjertness. Exercise capacity and selected physiological factors by ancestry and residential altitude—Cross-sectional studies of 9–10-year-old children in Tibet. High Alt Med Biol. 15:162–169, 2014.—Aim: Several physiological compensatory mechanisms have enabled Tibetans to live and work at high altitude, including increased ventilation and pulmonary diffusion capacity, both of which serve to increase oxygen transport in the blood. The aim of the present study was to compare exercise capacity (maximal power output) and selected physiological factors (arterial oxygen saturation and heart rate at rest and during maximal exercise, resting hemoglobin concentration, and forced vital capacity) in groups of native Tibetan children living at different residential altitudes (3700 vs. 4300 m above sea level) and across ancestry (native Tibetan vs. Han Chinese children living at the same altitude of 3700 m). Methods: A total of 430 9–10-year-old native Tibetan children from Tingri (4300 m) and 406 native Tibetan- and 406 Han Chinese immigrants (77% lowland-born and 33% highland-born) from Lhasa (3700 m) participated in two cross-sectional studies. The maximal power output (Wmax) was assessed using an ergometer cycle. Results: Lhasa Tibetan children had a 20% higher maximal power output (watts/kg) than Tingri Tibetan and 4% higher than Lhasa Han Chinese. Maximal heart rate, arterial oxygen saturation at rest, lung volume, and arterial oxygen saturation were significantly associated with exercise capacity at a given altitude, but could not fully account for the differences in exercise capacity observed between ancestry groups or altitudes. Conclusions: The superior exercise capacity in native Tibetans vs. Han Chinese may reflect a better adaptation to life at high altitude. Tibetans at the lower residential altitude of 3700 m demonstrated a better exercise capacity than residents at a higher altitude of 4300 m when measured at their respective residential altitudes. Such altitude- or ancestry-related difference could not be fully attributed to the physiological factors measured. PMID:24836751

Assessment of protein synthesis in highly aerobic canine species at the onset and during exercise training.

PubMed

Miller, Benjamin F; Ehrlicher, Sarah E; Drake, Joshua C; Peelor, Frederick F; Biela, Laurie M; Pratt-Phillips, Shannon; Davis, Michael; Hamilton, Karyn L

2015-04-01

Canis lupus familiaris, the domesticated dog, is capable of extreme endurance performance. The ability to perform sustained aerobic exercise is dependent on a well-developed mitochondrial reticulum. In this study we examined the cumulative muscle protein and DNA synthesis in groups of athletic dogs at the onset of an exercise training program and following a strenuous exercise training program. We hypothesized that both at the onset and during an exercise training program there would be greater mitochondrial protein synthesis rates compared with sedentary control with no difference in mixed or cytoplasmic protein synthesis rates. Protein synthetic rates of three protein fractions and DNA synthesis were determined over 1 wk using (2)H2O in competitive Alaskan Huskies and Labrador Retrievers trained for explosive device detection. Both groups of dogs had very high rates of skeletal muscle protein synthesis in the sedentary state [Alaskan Huskies: Mixed = 2.28 ± 0.12, cytoplasmic (Cyto) = 2.91 ± 0.10, and mitochondrial (Mito) = 2.62 ± 0.07; Labrador Retrievers: Mixed = 3.88 ± 0.37, Cyto = 3.85 ± 0.06, and Mito = 2.92 ± 0.20%/day]. Mitochondrial (Mito) protein synthesis rates did not increase at the onset of an exercise training program. Exercise-trained dogs maintained Mito protein synthesis during exercise training when mixed (Mixed) and cytosolic (Cyto) fractions decreased, and this coincided with a decrease in p-RpS6 but also a decrease in p-ACC signaling. Contrary to our hypothesis, canines did not have large increases in mitochondrial protein synthesis at the onset or during an exercise training program. However, dogs have a high rate of protein synthesis compared with humans that perhaps does not necessitate an extra increase in protein synthesis at the onset of aerobic exercise training. Copyright © 2015 the American Physiological Society.

Core Stability Exercise Versus General Exercise for Chronic Low Back Pain.

PubMed

Coulombe, Brian J; Games, Kenneth E; Neil, Elizabeth R; Eberman, Lindsey E

2017-01-01

Reference: Wang XQ, Zheng JJ, Yu ZW, et al. A meta-analysis of core stability exercise versus general exercise for chronic low back pain. PLoS One. 2012;7(12):e52082. Clinical Questions: Is core stability exercise more effective than general exercise in the treatment of patients with nonspecific low back pain (LBP)?  The authors searched the following databases: China Biological Medicine disc, Cochrane Library, Embase, and PubMed from 1970 through 2011. The key medical subject headings searched were chronic pain, exercise, LBP, lumbosacral region, and sciatica.  Randomized controlled trials comparing core stability exercise with general exercise in the treatment of chronic LBP were investigated. Participants were male and female adults with LBP for at least 3 months that was not caused by a specific known condition. A control group receiving general exercise and an experimental group receiving core stability exercise were required for inclusion in the meta-analysis. Core stability was defined as the ability to ensure a stable neutral spine position, but the type of exercise was not specified. Outcome measures of pain intensity, back-specific functional status, quality of life, and work absenteeism were recorded at 3-, 6-, and 12-month intervals.  The study design, participant information, description of interventions in the control and experimental groups, outcome measures, and follow-up period were extracted. The mean difference (MD) and 95% confidence interval (CI) were calculated to evaluate statistical significance. Risk of bias was assessed using the Cochrane Collaboration Recommendations, and all articles were rated as high risk for other bias with no further explanation given.  Five studies involving 414 patients were included. Four studies assessed pain intensity using the visual analog scale or numeric rating scale. In the core stability exercise group, the reduction in pain was significant at 3 months (MD = -1.29, 95% CI = -2.47, -0.11; P = .003) but not at 6 months (MD = -0.50, 95% CI = -1.36, 0.35; P = .26). Functional status was improved at 3 months (MD = -7.14, 95% CI = -11.64, -2.65; P = .002) but not at 6 months (MD = -0.50, 95% CI = 0.36, 0.35; P = .26) or 12 months (MD = -0.32, 95% CI = -0.87, 0.23; P = .25). All of the included studies assessed back-specific functional status: 4 used the Oswestry Disability Index and 1 used the Roland-Morris Disability Questionnaire. Patients in the core stability exercise groups experienced improved functional status versus the general exercise group at 3 months (MD = -7.14, 95% CI = -11.64, -2.65; P = .002); no results were recorded at 6 or 12 months.  In the short term, core stability exercise was more effective than general exercise for decreasing pain and increasing back-specific functional status in patients with LBP.

Sing Me the Creation: A Sourcebook for Poets and Teachers, and for All Who Wish To Develop the Life of the Imagination.

ERIC Educational Resources Information Center

Matthews, Paul

This resource book contains over 300 exercises and games for individual and group work in creative writing. Though the book's exercises are intended for group work with adults, teachers of children will encounter many new ideas for the classroom, and individuals working alone will have no difficulty adapting the exercises to their needs. The…

Exercise therapy in oncology rehabilitation in Australia: A mixed-methods study.

PubMed

Dennett, Amy M; Peiris, Casey L; Shields, Nora; Morgan, Delwyn; Taylor, Nicholas F

2017-10-01

Oncology rehabilitation improves outcomes for cancer survivors but little is known about program availability in Australia. The aims of this study were: to describe oncology rehabilitation programs in Australia: determine whether the exercise component of programs is consistent with guidelines: and to explore barriers and facilitators to program implementation. A sequential, explanatory mixed-methods study was completed in two phases: (1) a survey of Australian oncology rehabilitation programs; and (2) purposively sampled follow-up semistructured interviews with senior clinicians working in oncology rehabilitation who were involved with exercise prescription. Hospitals and/or cancer centers from 42 public hospital health networks (representing 163 hospitals) and 39 private hospitals were contacted to identify 31 oncology rehabilitation programs. All 31 surveys were returned (100% response rate). Programs were typically multidisciplinary, ran twice weekly, provided education and exercise and included self-management strategies. Exercise prescription and progression was patient centered and included a combination of resistance and aerobic training supplemented by balance, pelvic floor, and core stability exercises. Challenges to implementation included a lack of awareness of programs in the community and organizational barriers such as funding. Strong links with oncologists facilitated program referrals. Despite evidence to support oncology rehabilitation, there are few programs in Australia and there are challenges that limit it becoming part of standard practice. Programs that exist are multidisciplinary with a focus on exercise with the majority of programs following a cardiac rehabilitation model of care. © 2016 John Wiley & Sons Australia, Ltd.

Effect of hypoxia and hyperoxia on exercise performance in healthy individuals and in patients with pulmonary hypertension: a systematic review.

PubMed

Ulrich, Silvia; Schneider, Simon R; Bloch, Konrad E

2017-12-01

Exercise performance is determined by oxygen supply to working muscles and vital organs. In healthy individuals, exercise performance is limited in the hypoxic environment at altitude, when oxygen delivery is diminished due to the reduced alveolar and arterial oxygen partial pressures. In patients with pulmonary hypertension (PH), exercise performance is already reduced near sea level due to impairments of the pulmonary circulation and gas exchange, and, presumably, these limitations are more pronounced at altitude. In studies performed near sea level in healthy subjects, as well as in patients with PH, maximal performance during progressive ramp exercise and endurance of submaximal constant-load exercise were substantially enhanced by breathing oxygen-enriched air. Both in healthy individuals and in PH patients, these improvements were mediated by a better arterial, muscular, and cerebral oxygenation, along with a reduced sympathetic excitation, as suggested by the reduced heart rate and alveolar ventilation at submaximal isoloads, and an improved pulmonary gas exchange efficiency, especially in patients with PH. In summary, in healthy individuals and in patients with PH, alterations in the inspiratory Po 2 by exposure to hypobaric hypoxia or normobaric hyperoxia reduce or enhance exercise performance, respectively, by modifying oxygen delivery to the muscles and the brain, by effects on cardiovascular and respiratory control, and by alterations in pulmonary gas exchange. The understanding of these physiological mechanisms helps in counselling individuals planning altitude or air travel and prescribing oxygen therapy to patients with PH.

Omega-3 fatty acid supplementation enhances stroke volume and cardiac output during dynamic exercise.

PubMed

Walser, Buddy; Stebbins, Charles L

2008-10-01

Docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) have beneficial effects on cardiovascular function. We tested the hypotheses that dietary supplementation with DHA (2 g/day) + EPA (3 g/day) enhances increases in stroke volume (SV) and cardiac output (CO) and decreases in systemic vascular resistance (SVR) during dynamic exercise. Healthy subjects received DHA + EPA (eight men, four women) or safflower oil (six men, three women) for 6 weeks. Both groups performed 20 min of bicycle exercise (10 min each at a low and moderate work intensity) before and after DHA + EPA or safflower oil treatment. Mean arterial pressure (MAP), heart rate (HR), SV, CO, and SVR were assessed before exercise and during both workloads. HR was unaffected by DHA + EPA and MAP was reduced, but only at rest (88 +/- 5 vs. 83 +/- 4 mm Hg). DHA + EPA augmented increases in SV (14.1 +/- 6.3 vs. 32.3 +/- 8.7 ml) and CO (8.5 +/- 1.0 vs. 10.3 +/- 1.2 L/min) and tended to attenuate decreases in SVR (-7.0 +/- 0.6 vs. -10.1 +/- 1.6 mm Hg L(-1) min(-1)) during the moderate workload. Safflower oil treatment had no effects on MAP, HR, SV, CO or SVR at rest or during exercise. DHA + EPA-induced increases in SV and CO imply that dietary supplementation with these fatty acids can increase oxygen delivery during exercise, which may have beneficial clinical implications for individuals with cardiovascular disease and reduced exercise tolerance.

Phosphocreatine resynthesis during recovery in different muscles of the exercising leg by 31P-MRS.

PubMed

Yoshida, T; Abe, D; Fukuoka, Y

2013-10-01

To investigate the high-energy phosphate metabolism by (31) P-nuclear magnetic resonance spectroscopy during off-transition of exercise in different muscle groups, such as calf muscles and biceps femoris muscles, seven male long-distance runners (LDR) and nine untrained males (UT) performed both submaximal constant and incremental exercises. The relative exercise intensity was set at 60% of the maximal work rate (60%W max) during both knee flexion and plantar flexion submaximal constant load exercises. The relative areas under the inorganic phosphate (Pi ) and phosphocreatine (PCr) peaks were determined. During the 5-min recovery following the 60%W max, the time constant for the PCr off-kinetics was significantly faster in the plantar flexion (LDR: 17.3 ± 3.6 s, UT: 26.7 ± 6.7 s) than in the knee flexion (LDR: 29.7 ± 4.7 s, UT: 42.7 ± 2.8 s, P < 0.05). In addition, a significantly faster PCr off-kinetics was observed in LDR than in UT for both exercises. The ratio of Pi to PCr (Pi /PCr) during exercise was significantly lower during the plantar flexion than during the knee flexion (P < 0.01). These findings indicated that the calf muscles had relatively higher potential for oxidative capacity than that of biceps femoris muscles with an association of training status. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Separate and combined effects of exercise training and weight loss on exercise efficiency and substrate oxidation.

PubMed

Amati, Francesca; Dubé, John J; Shay, Chris; Goodpaster, Bret H

2008-09-01

Perturbations in body weight have been shown to affect energy expenditure and efficiency during physical activity. The separate effects of weight loss and exercise training on exercise efficiency or the proportion of energy derived from fat oxidation during physical activity, however, are not known. The purpose of this study was to determine the separate and combined effects of exercise training and weight loss on metabolic efficiency, economy (EC), and fat oxidation during steady-state moderate submaximal exercise. Sixty-four sedentary older (67 +/- 0.5 yr) overweight to obese (30.7 +/- 0.4 kg/m(2)) volunteers completed 4 mo of either diet-induced weight loss (WL; n = 11), exercise training (EX; n = 36), or the combination of both interventions (WLEX; n = 17). Energy expenditure, gross efficiency (GE), EC, and proportion of energy expended from fat (EF) were determined during a 1-h submaximal (50% of peak aerobic capacity) cycle ergometry exercise before the intervention and at the same absolute work rate after the intervention. We found that EX increased GE by 4.7 +/- 2.2%. EC was similarly increased by 4.2 +/- 2.1% by EX. The addition of concomitant WL to EX (WLEX) resulted in greater increases in GE (9.0 +/- 3.3%) compared with WL alone but not compared with EX alone. These effects remained after adjusting for changes in lean body mass. The proportion of energy derived from fat during the bout of moderate exercise increased with EX and WLEX but not with WL. From these findings, we conclude that exercise training, either alone or in combination with weight loss, increases both exercise efficiency and the utilization of fat during moderate physical activity in previously sedentary, obese older adults. Weight loss alone, however, significantly improves neither efficiency nor utilization of fat during exercise.

Ergogenic effects of beetroot juice supplementation during severe-intensity exercise in obese adolescents.

PubMed

Rasica, Letizia; Porcelli, Simone; Marzorati, Mauro; Salvadego, Desy; Vezzoli, Alessandra; Agosti, Fiorenza; De Col, Alessandra; Tringali, Gabriella; Jones, Andrew M; Sartorio, Alessandro; Grassi, Bruno

2018-04-25

Previous studies showed a higher O 2 cost of exercise, and therefore a reduced exercise tolerance, in obese patients during constant work rate (CWR) exercise compared to healthy subjects. Among the ergogenic effects of dietary nitrate (NO 3 -) supplementation in sedentary healthy subjects, a reduced O 2 cost and enhanced exercise tolerance have often been demonstrated. The aim of this study was to evaluate the effects of beetroot juice supplementation, rich in NO 3 -, on physiological variables associated with exercise tolerance in obese adolescents. In a double-blind, randomized, crossover study, ten obese adolescents (8F, 2M; age=16{plus minus}1 yr; BMI=35.2{plus minus}5.0 kg.m -2 ) were tested after 6 days of supplementation with beetroot juice (5 mmol NO 3 - per day) (BR) or placebo (PLA). Following each supplementation period, patients carried out two repetitions of 6-min moderate-intensity CWR exercise and one severe-intensity CWR exercise until exhaustion. Plasma NO 3 - concentration was significantly higher in BR vs. PLA (108{plus minus}37 vs. 15{plus minus}5 μM, P<0.0001). The O 2 cost of moderate-intensity exercise was not different in BR vs. PLA (13.3{plus minus}1.7 vs. 12.9{plus minus}1.1 mL.min -1 .W -1 , P=0.517). During severe-intensity exercise, signs of a reduced amplitude of the O 2 uptake slow component were observed in BR, in association with a significantly longer time to exhaustion (561{plus minus}198 s in BR vs. 457{plus minus}101 s in PLA, P=0.0143). In obese adolescents, short-term dietary NO 3 - supplementation is effective in improving exercise tolerance during severe-intensity exercise. This may prove to be useful in contrasting early fatigue and reduced physical activity in this at-risk population.

Cardiorespiratory endurance evaluation using heart rate analysis during ski simulator exercise and the Harvard step test in elementary school students.

PubMed

Lee, Hyo Taek; Roh, Hyo Lyun; Kim, Yoon Sang

2016-01-01

[Purpose] Efficient management using exercise programs with various benefits should be provided by educational institutions for children in their growth phase. We analyzed the heart rates of children during ski simulator exercise and the Harvard step test to evaluate the cardiopulmonary endurance by calculating their post-exercise recovery rate. [Subjects and Methods] The subjects (n = 77) were categorized into a normal weight and an overweight/obesity group by body mass index. They performed each exercise for 3 minutes. The cardiorespiratory endurance was calculated using the Physical Efficiency Index formula. [Results] The ski simulator and Harvard step test showed that there was a significant difference in the heart rates of the 2 body mass index-based groups at each minute. The normal weight and the ski-simulator group had higher Physical Efficiency Index levels. [Conclusion] This study showed that a simulator exercise can produce a cumulative load even when performed at low intensity, and can be effectively utilized as exercise equipment since it resulted in higher Physical Efficiency Index levels than the Harvard step test. If schools can increase sport durability by stimulating students' interests, the ski simulator exercise can be used in programs designed to improve and strengthen students' physical fitness.

Implementing 'The Math You Need' in an Introductory Physical Geology Course at California State University East Bay

NASA Astrophysics Data System (ADS)

Moran, J. E.

2011-12-01

The wide range of abilities in the student population at California State University East Bay, with a significant fraction of students under-prepared and requiring mathematics remediation, is a challenge to including mathematical concepts and exercises in our introductory geoscience courses. Student expectations that a geoscience course will not include quantitative work may result in math-phobics choosing the course and resisting quantitative work when presented with it. Introductory courses that are required for Geology and Environmental Science majors are also designated as General Education, which gives rise to a student group with a wide range of abilities and expectations. This presentation will focus on implementation of a series of online math tutorials for students in introductory geoscience courses called 'The Math You Need' (TMYN; http://serc.carleton.edu/mathyouneed/index.html). The program is implemented in a Physical Geology course, in which 2/3 of the students are typically non-majors. The Physical Geology course has a three hour lab each week and the lab exercises and lab manual offer several opportunities for application of TMYN. Many of the lab exercises include graphing, profiling, working with map scales, converting units, or using equations to calculate some parameter or solve for an unknown. Six TMYN modules covering topics using density calculations as applied to mineral properties and isostasy, graphing as applied to rock properties, earthquake location, and radiometric dating, and calculation of rates as applied to plate movement, stream discharge, and groundwater flow, are assigned as pre-labs to be completed before lab classes. TMYN skills are reinforced during lectures and lab exercises, as close in time as possible to students' exposure via TMYN. Pre- and post-tests give a measure of the effectiveness of TMYN in improving students' quantitative literacy.

An exercise protocol designed to control energy expenditure for long-term space missions.

PubMed

Matsuo, Tomoaki; Ohkawara, Kazunori; Seino, Satoshi; Shimojo, Nobutake; Yamada, Shin; Ohshima, Hiroshi; Tanaka, Kiyoji; Mukai, Chiaki

2012-08-01

Astronauts experience weight loss during spaceflight. Future space missions require a more efficient exercise program not only to maintain work efficiency, but also to control increased energy expenditure (EE). When discussing issues concerning EE incurred through exercise, excess post-exercise energy expenditure (EPEE) must also be considered. The aim of this study was to compare the total EE, including EPEE, induced by two types of interval cycling protocols with the total EE of a traditional, continuous cycling protocol. There were 10 healthy men, ages 20 to 31 yr, who completed 3 exercise sessions: sprint interval training (SIT) consisting of 7 sets of 30-s cycling at 120% VO2max with a 15-s rest between each bout; high-intensity interval aerobic training (HIAT) consisting of 3 sets of 3-min cycling at 80-90% VO2max with a 2-min active rest at 50% VO2max; and continuous aerobic training (CAT) consisting of 40 min of cycling at 60-65% VO2max. During each session, resting metabolic rate, exercise EE, and a 180-min post-exercise EE were measured. The EPEEs during the SIT, HIAT, and CAT averaged 32 +/- 19, 21 +/- 16, and 13 +/- 13 kcal, and the total EE for an entire exercise/ rest session averaged 109 +/- 20, 182 +/- 17, and 363 +/- 45 kcal, respectively. While the EPEE after the CAT was significantly less than after the SIT, the total EE with the CAT was the greatest of the three. The SIT and HIAT would be potential protocols to control energy expenditure for long space missions.

Prior exercise speeds pulmonary oxygen uptake kinetics and increases critical power during supine but not upright cycling.

PubMed

Goulding, Richie P; Roche, Denise M; Marwood, Simon

2017-09-01

What is the central question of this study? Critical power (CP) represents the highest work rate for which a metabolic steady state is attainable. The physiological determinants of CP are unclear, but research suggests that CP might be related to the time constant of phase II oxygen uptake kinetics (τV̇O2). What is the main finding and its importance? We provide the first evidence that τV̇O2 is mechanistically related to CP. A reduction of τV̇O2 in the supine position was observed alongside a concomitant increase in CP. This effect may be contingent on measures of oxygen availability derived from near-infrared spectroscopy. Critical power (CP) is a fundamental parameter defining high-intensity exercise tolerance and is related to the time constant of phase II pulmonary oxygen uptake kinetics (τV̇O2). To test the hypothesis that this relationship is causal, we determined the impact of prior exercise ('priming') on CP and τV̇O2 in the upright and supine positions. Seventeen healthy men were assigned to either upright or supine exercise groups, whereby CP, τV̇O2 and muscle deoxyhaemoglobin kinetics (τ [HHb] ) were determined via constant-power tests to exhaustion at four work rates with (primed) and without (control) priming exercise at ∼31%Δ. During supine exercise, priming reduced τV̇O2 (control 54 ± 18 s versus primed 39 ± 11 s; P < 0.001), increased τ [HHb] (control 8 ± 4 s versus primed 12 ± 4 s; P = 0.003) and increased CP (control 177 ± 31 W versus primed 185 ± 30 W, P = 0.006) compared with control conditions. However, priming exercise had no effect on τV̇O2 (control 37 ± 12 s versus primed 35 ± 8 s; P = 0.82), τ [HHb] (control 10 ± 5 s versus primed 14 ± 10 s; P = 0.10) or CP (control 235 ± 42 W versus primed 232 ± 35 W; P = 0.57) during upright exercise. The concomitant reduction of τV̇O2 and increased CP following priming in the supine group, effects that were absent in the upright group, provide the first experimental evidence that τV̇O2 is mechanistically related to critical power. The increased τ [HHb+Mb] suggests that this effect was mediated, at least in part, by improved oxygen availability. © 2017 The Authors. Experimental Physiology © 2017 The Physiological Society.