Central and peripheral adaptations of the gas transport system to one-leg training

1981 ◽  
Vol 59 (11) ◽  
pp. 1146-1154 ◽  
Author(s):  
S. G. Thomas ◽  
D. A. Cunningham ◽  
M. J. Plyley ◽  
D. R. Boughner ◽  
R. A. Cook
Keyword(s):  
Cardiac Output ◽  
Oxygen Uptake ◽  
Endurance Training ◽  
Maximal Oxygen Uptake ◽  
Enzyme Activities ◽  
Cardiovascular Responses ◽  
Cycle Ergometer ◽  
Left Ventricular ◽  
Enzyme Analysis ◽  
Ergometer Exercise

The role of central and peripheral adaptations in the response to endurance training was examined. Changes in cardiac structure and function, oxygen extraction, and muscle enzyme activities following one-leg training were studied.Eleven subjects (eight females, three males) trained on a cycle ergometer 4 weeks with one leg (leg 1), then 4 weeks with the second leg (leg 2). Cardiovascular responses to exercise with both legs and each leg separately were evaluated at entry (T1), after 4 weeks of training (T2), and after a second 4 weeks of training (T3). Peak oxygen uptake ([Formula: see text] peak) during exercise with leg 1 (T1 to T2 increased 19.8% (P < 0.05) and during exercise with leg 2 (T2 to T3 increased 16.9% (P < 0.05). Maximal oxygen uptake with both legs increased 7.9% from T1 to T2 and 9.4% from T2 to T3 (P < 0.05). During exercise at 60% of [Formula: see text] peak, cardiac output [Formula: see text] was increased significantly only when the trained leg was exercised. [Formula: see text] increased 12.2% for leg 1 between T1 and T2 and 13.0% for leg 2 between T2 and T3 (P < 0.05). M-mode echocardiographic assessment of left ventricular internal diameter at diastole and peak velocity of circumferential fibre shortening at rest or during supine cycle ergometer exercise at T1 and T3 revealed no training induced changes in cardiac dimensions or function. Enzyme analysis of muscle biopsy samples from the vastus lateralis (At T1, T2, T3) revealed no consistent pattern of change in aerobic (malate dehydrogenase and 3-hydroxyacyl-CoA dehydrogenase) or anaerobic (phosphofructokinase, lactate dehydroginase, and creatine kinase) enzyme activities. Increases in cardiac output and maximal oxygen uptake which result from short duration endurance training can be achieved, therefore, without measurable central cardiac adaptation. The absence of echocardio-graphically determined changes in cardiac dimensions and contractility and the absence of an increase in cardiac output during exercise with the nontrained leg following training of the contralateral limb support this conclusion.

scholarly journals Determinants of maximal oxygen uptake in severe acute hypoxia

2003 ◽  
Vol 284 (2) ◽  
pp. R291-R303 ◽  
Author(s):  
J. A. L. Calbet ◽  
R. Boushel ◽  
G. Rådegran ◽  
H. Søndergaard ◽  
P. D. Wagner ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Gas Exchange ◽  
Oxygen Uptake ◽  
Maximal Oxygen Uptake ◽  
Acute Hypoxia ◽  
Cycle Ergometer ◽  
Pulmonary Gas Exchange ◽  
Leg Blood Flow ◽  
Ergometer Exercise

To unravel the mechanisms by which maximal oxygen uptake (V˙o 2 max) is reduced with severe acute hypoxia in humans, nine Danish lowlanders performed incremental cycle ergometer exercise to exhaustion, while breathing room air (normoxia) or 10.5% O2 in N2(hypoxia, ∼5,300 m above sea level). With hypoxia, exercise PaO2 dropped to 31–34 mmHg and arterial O2 content (CaO2 ) was reduced by 35% ( P < 0.001). Forty-one percent of the reduction in CaO2 was explained by the lower inspired O2 pressure (Pi O2 ) in hypoxia, whereas the rest was due to the impairment of the pulmonary gas exchange, as reflected by the higher alveolar-arterial O2 difference in hypoxia ( P < 0.05). Hypoxia caused a 47% decrease inV˙o 2 max (a greater fall than accountable by reduced CaO2 ). Peak cardiac output decreased by 17% ( P < 0.01), due to equal reductions in both peak heart rate and stroke volume ( P < 0.05). Peak leg blood flow was also lower (by 22%, P < 0.01). Consequently, systemic and leg O2 delivery were reduced by 43 and 47%, respectively, with hypoxia ( P < 0.001) correlating closely with V˙o 2 max( r = 0.98, P < 0.001). Therefore, three main mechanisms account for the reduction ofV˙o 2 max in severe acute hypoxia: 1) reduction of Pi O2 , 2) impairment of pulmonary gas exchange, and 3) reduction of maximal cardiac output and peak leg blood flow, each explaining about one-third of the loss inV˙o 2 max.

Cardiovascular responses to treadmill and cycle ergometer exercise in children and adults

1997 ◽  
Vol 83 (3) ◽  
pp. 948-957 ◽  
Author(s):  
Kenneth R. Turley ◽  
Jack H. Wilmore
Keyword(s):  
Stroke Volume ◽  
Peripheral Resistance ◽  
Cardiovascular Responses ◽  
Cycle Ergometer ◽  
Left Ventricular ◽  
Absolute Amount ◽  
Exercise Tests ◽  
Exercise Modality ◽  
Cycle Ergometer Exercise ◽  
Ergometer Exercise

Turley, Kenneth R., and Jack H. Wilmore. Cardiovascular responses to treadmill and cycle ergometer exercise in children and adults. J. Appl. Physiol. 83(3): 948–957, 1997.—This study was conducted to determine whether submaximal cardiovascular responses at a given rate of work are different in children and adults, and, if different, what mechanisms are involved and whether the differences are exercise-modality dependent. A total of 24 children, 7 to 9 yr old, and 24 adults, 18 to 26 yr old (12 males and 12 females in each group), participated in both submaximal and maximal exercise tests on both the treadmill and cycle ergometer. With the use of regression analysis, it was determined that cardiac output (Q˙) was significantly lower ( P ≤ 0.05) at a given O2 consumption level (V˙o 2, l/min) in boys vs. men and in girls vs. women on both the treadmill and cycle ergometer. The lower Q˙ in the children was compensated for by a significantly higher ( P ≤ 0.05) arterial-mixed venous O2difference to achieve the same or similarV˙o 2. Furthermore, heart rate and total peripheral resistance were higher and stroke volume was lower in the children vs. in the adult groups on both exercise modalities. Stroke volume at a given rate of work was closely related to left ventricular mass, with correlation coefficients ranging from r = 0.89–0.92 and r = 0.88–0.93 in the males and females, respectively. It was concluded that submaximal cardiovascular responses are different in children and adults and that these differences are related to smaller hearts and a smaller absolute amount of muscle doing a given rate of work in the children. The differences were not exercise-modality dependent.

Phlebotomy eliminates the maximal cardiac output response to six weeks of exercise training

2014 ◽  
Vol 306 (10) ◽  
pp. R752-R760 ◽  
Author(s):  
Thomas C. Bonne ◽  
Gregory Doucende ◽  
Daniela Flück ◽  
Robert A. Jacobs ◽  
Nikolai B. Nordsborg ◽  
...  
Keyword(s):  
Cardiac Output ◽  
Exercise Training ◽  
Endurance Training ◽  
Blood Volume ◽  
Cycle Ergometer ◽  
Training Period ◽  
Training Intervention ◽  
Functional Changes ◽  
Ergometer Exercise ◽  
Maximal Cardiac Output

With this study we tested the hypothesis that 6 wk of endurance training increases maximal cardiac output (Q̇max) relatively more by elevating blood volume (BV) than by inducing structural and functional changes within the heart. Nine healthy but untrained volunteers (V̇o2max 47 ± 5 ml·min−1·kg−1) underwent supervised training (60 min; 4 times weekly at 65% V̇o2max for 6 wk), and Q̇max was determined by inert gas rebreathing during cycle ergometer exercise before and after the training period. After the training period, blood volume (determined in duplicates by CO rebreathing) was reestablished to pretraining values by phlebotomy and Q̇max was quantified again. Resting echography revealed no structural heart adaptations as a consequence of the training intervention. After the training period, plasma volume (PV), red blood cell volume (RBCV), and BV increased ( P < 0.05) by 147 ± 168 (5 ± 5%), 235 ± 64 (10 ± 3%), and 382 ± 204 ml (7 ± 4%), respectively. V̇o2max was augmented ( P < 0.05) by 10 ± 7% after the training period and decreased ( P < 0.05) by 8 ± 7% with phlebotomy. Concomitantly, Q̇max was increased ( P < 0.05) from 18.9 ± 2.1 to 20.4 ± 2.3 l/min (9 ± 6%) as a consequence of the training intervention, and after normalization of BV by phlebotomy Q̇max returned to pretraining values (18.1 ± 2.5 l/min; 12 ± 5% reversal). Thus the exercise training-induced increase in BV is the main mechanism increasing Q̇max after 6 wk of endurance training in previously untrained subjects.

High-intensity endurance training in 20- to 30- and 60- to 70-yr-old healthy men

1990 ◽  
Vol 69 (5) ◽  
pp. 1792-1798 ◽  
Author(s):  
L. Makrides ◽  
G. J. Heigenhauser ◽  
N. L. Jones
Keyword(s):  
Cardiac Output ◽  
Stroke Volume ◽  
Endurance Training ◽  
High Intensity ◽  
Cycle Ergometer ◽  
Short Term ◽  
Vascular Conductance ◽  
Isokinetic Test ◽  
Ergometer Exercise ◽  
Young Subjects

Factors contributing to maximal incremental and short-term exercise capacity were measured before and after 12 wk of high-intensity endurance training in 12 old (60-70 yr) and 10 young (20-30 yr) sedentary healthy males. Peak O2 uptake in incremental cycle ergometer exercise increased from 1.60 +/- 0.073 to 2.21 +/- 0.073 (SE) l/min (38% increase) in the old subjects and from 2.54 +/- 0.141 to 3.26 +/- 0.181 l/min (29%) in the young subjects. Peak cardiac output, estimated by extrapolation from a series of submaximal measurements by the CO2 rebreathing method, increased by 30% (from 12.7 to 16.5 l/min) in the old subjects, associated with a 6% increase (from 126 to 135 ml/l) in arteriovenous O2 difference; in the young subjects there were equal 14% increases in both variables (18.0 to 20.5 l/min and 140 to 159 ml/l, respectively). Submaximal mean arterial pressure and cardiac output were lower posttraining in the old subjects; total vascular conductance and cardiac stroke volume increased. Although peak power at the start of a short-term maximal isokinetic test did not change, total work accomplished in 30 s at a pedaling frequency of 110 revolutions/min increased in both groups, from 11.2 to 12.6 kJ and from 15.7 to 16.9 kJ in the old and young, respectively; fatigue during the 30-s test was less, and postexercise plasma lactate concentrations were lower. In older subjects, increases in aerobic power after high-intensity endurance training are at least as large as in younger subjects and are associated with increases in vascular conductance, maximal cardiac output, and stroke volume.

Acute and chronic effects of exercise on leptin levels in humans

1997 ◽  
Vol 83 (1) ◽  
pp. 5-10 ◽  
Author(s):  
Louis Pérusse ◽  
Gregory Collier ◽  
Jacques Gagnon ◽  
Arthur S. Leon ◽  
D. C. Rao ◽  
...  
Keyword(s):  
Exercise Training ◽  
Oxygen Uptake ◽  
Endurance Training ◽  
Body Fat ◽  
Fat Mass ◽  
Maximal Oxygen Uptake ◽  
Cycle Ergometer ◽  
Chronic Effects ◽  
Before And After ◽  
Acute And Chronic Effects

Pérusse, Louis, Gregory Collier, Jacques Gagnon, Arthur S. Leon, D. C. Rao, James S. Skinner, Jack H. Wilmore, André Nadeau, Paul Z. Zimmet, and Claude Bouchard. Acute and chronic effects of exercise on leptin levels in humans. J. Appl. Physiol. 83(1): 5–10, 1997.—The acute (single bout of exercise) and chronic (exercise training) effects of exercise on plasma leptin were investigated in 97 sedentary adult men ( n = 51) and women ( n = 46) participating in the HERITAGE Family Study. Exercise training consisted of a standardized 20-wk endurance training program performed in the laboratory on a computer-controlled cycle ergometer. Maximal oxygen uptake, body composition assessed by hydrostatic weighing, and fasting insulin level were also measured before and after training. Pre- and posttraining blood samples were obtained before and after completion of a maximal exercise test on the cycle ergometer. Exercise training resulted in significant changes in maximal oxygen uptake (increase in both genders) and body compostion (reduction of fat mass in men and increase in fat-free mass in women). There were considerable interindividual differences in the leptin response to acute and chronic effects of exercise, some individuals showing either increase or reduction in leptin, others showing almost no change. On average, leptin levels were not acutely affected by exercise. After endurance training was completed, leptin levels decreased significantly in men (from 4.6 to 3.9 ng/ml; P = 0.004) but not in women. However, after the training-induced changes in body fat mass were accounted for, the effects of exercise training were no longer significant. Most of the variation observed in leptin levels after acute exercise or endurance training appears to be within the confidence intervals of the leptin assay. We conclude that there are no meaningful acute or chronic effects of exercise, independent of the amount of body fat, on leptin levels in humans.

scholarly journals How to Be 80 Year Old and Have a VO2maxof a 35 Year Old

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Trine Karlsen ◽  
Ingeborg Megård Leinan ◽  
Fredrik Hjulstad Bækkerud ◽  
Kari Margrethe Lundgren ◽  
Atefe Tari ◽  
...  
Keyword(s):  
Physical Activity ◽  
Oxygen Uptake ◽  
Maximal Oxygen Uptake ◽  
Left Ventricular ◽  
Left Ventricular Filling ◽  
Maximal Heart Rate ◽  
Cardiopulmonary Fitness ◽  
Systolic And Diastolic Function ◽  
High Level ◽  
Ventricular Filling

Background. To discuss the cardiovascular and pulmonary physiology and common risk factors of an 80-year-old man with a world record maximal oxygen uptake of 50 mL·kg−1·min−1.Methods. Case report.Results. His maximal oxygen uptake of 3.31 L·min−1, maximal heart rate of 175 beats·min−1, and maximal oxygen pulse of 19 mL·beats−1are high. He is lean (66.6 kg) and muscular (49% skeletal muscle mass). His echo parameters of mitral flow (left ventricular filling,E= 82 cm·s−1andE/A= 1.2) were normal for 40- to 60-year-old men. Systolic and diastolic function increased adequately during exercise, with no increase in left ventricular filling pressure. He has excellent pulmonary function (FVC = 4.31 L, FEV1 = 3.41, FEV1/FVC = 0.79, and DLCO = 12.0 Si1) and normal FMD and blood volumes (5.8 L). He has a high level of daily activity (10,900 steps·day−1and 2:51 hours·day−1of physical activity) and a lifelong history of physical activity.Conclusion. The man is in excellent cardiopulmonary fitness and is highly physically active. His cardiac and pulmonary functions are above expectations for his age, and his VO2maxis comparable to that of an inactive 25-year-old and of a normal, active 35-year-old Norwegian man.

Polarized Versus High-Intensity Multimodal Training in Recreational Runners

2019 ◽  
Vol 14 (1) ◽  
pp. 105-112 ◽  
Author(s):  
Andrew J. Carnes ◽  
Sara E. Mahoney
Keyword(s):  
Body Composition ◽  
Oxygen Uptake ◽  
Endurance Training ◽  
Maximal Oxygen Uptake ◽  
High Intensity ◽  
Time Trial ◽  
Lower Volume ◽  
High Zone ◽  
Multimodal Training ◽  
Recreational Runners

Purpose: This study longitudinally compared changes in running performance (5-km time trial) and fitness (maximal oxygen uptake [VO2max] and body composition [BC]) between polarized training and CrossFit Endurance (CFE) in recreational runners. Methods: Participants (N = 21) completed 12 wk of CFE or polarized endurance training (POL). Both groups trained 5 d·wk−1. POL ran 5 d·wk−1, whereas CFE ran 3 d·wk−1 and performed CrossFit 3 d·wk−1 (run + CrossFit 1 d·wk−1). Intensity was classified as low, moderate, or high (zone 1, 2, or 3) according to ventilatory thresholds. POL was prescribed greater volume (295 [67] min·wk−1), distributed as 85%/5%/10% in Z1/Z2/Z3. CFE emphasized a lower volume (110 [18] min·wk−1) distribution of 48%/8%/44%. Results: POL ran 283 (75.9) min·wk−1 and 47.3 (11.6) km·wk−1, both exceeding the 117 (32.2) min·wk−1 and 19.3 (7.17) km·wk−1 in CFE (P < .001). The POL distribution (74%/11%/15%) had greater total and percentage Z1 (P < .001) than CFE (46%/15%/39%), which featured higher percentage Z3 (P < .001). Time trial improved −93.8 (40.4) s (−6.21% [2.16%]) in POL (P < .001) and −84.2 (65.7) s (−5.49% [3.56%]) in CFE (P = .001). BC improved by −2.45% (2.59%) fat in POL (P = .02) and −2.62% (2.53%) in CFE (P = .04). The magnitude of improvement was not different between groups for time trial (P = .79) or BC (P = .88). Both groups increased VO2max (P ≤ .01), but with larger magnitude (P = .04, d = 0.85) in POL (4.3 [3.6] mL·kg·min−1) than CFE (1.78 [1.9] mL·kg·min−1). Conclusions: Recreational runners achieved similar improvement in 5-km performance and BC through polarized training or CFE, but POL yielded a greater increase in VO2max. Extrapolation to longer distances requires additional research.

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