Comparison of cardiovascular adaptations to long-term arm and leg exercise in wheelchair athletes versus long-distance runners.

The effect of long-term arm exercise on cardiac morphology and function is unknown. To study these effects, highly trained wheelchair athletes were compared with long-distance runners and controls. In addition, the wheelchair athletes were compared with the long-distance runners to determine if long-term leg exercise confers a training effect during the performance of dynamic arm exercise. The study included 31 male subjects (mean age of 33+/-5 years), who comprised 3 groups matched for age and weight: wheelchair athletes (n = 9), long-distance runners (n = 12), and healthy controls (n = 10). All underwent echocardiography at rest and arm ergometry exercise testing with expiratory gas analysis. The peak work rate during arm exercise was highest among the wheelchair athletes, and was significantly higher in both groups of trained athletes compared with the control group (p<0.001). Runners demonstrated a significantly lower submaximal heart rate response to arm exercise compared with wheelchair and control subjects. Wheelchair athletes had increased left ventricular (LV) volume and mass by echocardiography compared with controls, but not to the same degree as that of runners. Although chamber dimensions and wall thickness did not differ among the groups, the LV volume index tended to be largest in the runners. Doppler indexes of diastolic LV filling were similar between the trained and untrained subjects. These data demonstrate that both long-term arm and leg exercise yield increases in LV volume and mass compared with untrained control subjects, although to a lesser degree in arm-trained athletes. Runners demonstrated a transfer of training effect in the performance of dynamic arm exercise, as demonstrated by their ability to achieve a higher peak work rate than controls, and showed a lower heart rate response to submaximal exercise than the wheelchair athletes and control subjects.