Do athletes have “the athlete heart?”

Yoga versus physical exercise for cardio-respiratory fitness in adolescent school children: a randomized controlled trial

Background Yoga is very effective in improving health especially cardio-respiratory fitness and also overall performance in adolescents. There are no large numbers of randomized controlled studies conducted on comparing yoga with physical activity for cardio-respiratory fitness in adolescent school children with large sample size. Objective Aerobic training is known to improve physical and cardio-respiratory fitness in children. Cardio-respiratory fitness is an important indicator of health in children. In this study we evaluate the effects of yoga versus physical exercise training on cardio-respiratory fitness in adolescent school children. Subjects Eight hundred two school students from 10 schools across four districts were recruited for this study. Methods In this prospective two arm RCT around 802 students were randomized to receive daily one hour yoga training (n = 411) or physical exercise (n = 391) over a period of two months. VO2 max was estimated using 20 m shuttle run test. However, yoga (n = 377) and physical exercise (n = 371) students contributed data to the analyses. Data was analysed using students t test. Results There was a significant improvement in VO2 max using 20 m Shuttle run test in both yoga (p < 0.001) and exercise (p < 0.001) group following intervention. There was no significant change in VO2 max between yoga and physical exercise group following intervention. However, in the subgroup with an above median cut-off of VO2 max; there was a significant improvement in yoga group compared to control group following intervention (p = 0.03). Conclusion The results suggest yoga can improve cardio-respiratory fitness and aerobic capacity as physical exercise intervention in adolescent school children.

Myocardial function and aerobic fitness in adolescent females

A recent report indicated that variations in myocardial functional (systolic and diastolic) responses to exercise do not contribute to inter-individual differences in aerobic fitness (peak VO(2)) among young males. This study was designed to investigate the same question among adolescent females. Thirteen highly fit adolescent football (soccer) players (peak VO(2) 43.5 ± 3.4 ml kg(-1) min(-1)) and nine untrained girls (peak VO(2) 36.0 ± 5.1 ml kg(-1) min(-1)) matched for age underwent a progressive cycle exercise test to exhaustion. Cardiac variables were measured by standard echocardiographic techniques. Maximal stroke index was greater in the high-fit group (50 ± 5 vs. 41 ± 4 ml m(-2)), but no significant group differences were observed in maximal heart rate or arterial venous oxygen difference. Increases in markers of both systolic (ejection rate, tissue Doppler S') and diastolic (tissue Doppler E', mitral E velocity) myocardial functions at rest and during the acute bout of exercise were similar in the two groups. This study suggests that among healthy adolescent females, like young males, myocardial systolic and diastolic functional capacities do not contribute to inter-individual variability in physiologic aerobic fitness.

Influence of sex on the "Athlete's Heart" in trained cyclists

Compared to females, male endurance athletes have generally been considered to demonstrate greater values of cardiac mass and volume (the "athlete's heart"). However, studies addressing this issue have frequently failed to match training volumes between groups or provided inadequate adjustment of variables for body size and composition. This study compared echocardiographic anatomic features in 8 female and 8 male competitive cyclists with a similar training history. Conforming to most previous reports, left ventricular mass and end diastolic dimension, adjusted for fat free body mass and body surface area, respectively, were greater in the males (3.56+/-0.83gkg(-1) versus 2.50+/-0.38gkg(-1); 41.7+/-2.2mm and 37.4+/-2.5mm per BSA(0.5)). This study indicated that when training volume as well as body size and composition are considered, male endurance athletes exhibit greater cardiac dimensions and mass compared to their female counterparts.

Left ventricular response to dynamic exercise in young cyclists

PURPOSE

The purpose of this study was to compare cardiac physiological and dimensional responses to exercise in highly trained young male cyclists (mean age 13.7 +/- 1.0 yr) with those of nontrained boys.

METHODS

Ventricular systolic and diastolic dimensions were measured by two-dimensional echocardiography, and stroke volume was estimated by Doppler echocardiography during a progressive maximal upright cycle test.

RESULTS

At rest, the cyclists demonstrated larger left ventricular dimensions relative to body size than the nonathletes. Maximal stroke index and cardiac index were significantly greater in the cyclists. The pattern of stroke volume response to exercise was similar in the two groups, with an early rise and then plateau to exhaustion. Left ventricular diastolic dimension increased slightly at onset of exercise and then gradually declined as workload increased in both groups.

CONCLUSION

Factors responsible for the greater maximal stroke volume in young endurance athletes involve those variables that contribute to resting left ventricular diastolic filling (preload).