EFFECTS OF ENDURANCE TRAINING ON THE CARDIOVASCULAR-SYSTEM AND WATER COMPARTMENTS IN ELDERLY SUBJECTS

The effects of endurance training on the water compartments and the ca rdiovascular system were determined in 10 elderly subjects [age 62 +/- 2 yr, pretraining maximal oxygen consumption ((V) over dotO(2max))/kg = 25 +/- 2 ml.min(-1).kg(-1) body wt]. They trained on a cycloergomet er 3 times/wk for 16 wk (50-80% (V) over dotO(2max), then 80-85% (V) o ver dotO(2max)). They were checked at 8 wk, 16 wk, and 4 mo after detr aining. Training improved (V) over dotO(2max) (+16%) and induced plasm a volume expansion (+11%). No change in total body water, extracellula r fluid, interstitial and intracellular fluid volumes, fat-free mass, and body weight was detected in this small sample with training. Body fat mass decreased(-2.1 +/- 2.2 kg). Echocardiography at rest showed i ncreased fractional shortening and ejection fraction and decreased lef t ventricular end-systolic dimension (P < 0.05). Blood volume expansio n correlates with cardiac contractility and has an impact on cardiac f unction. These improvements are precarious, however, and are completel y lost after 4 mo of detraining, when elderly subjects lose the constr aints and the social stimulation of the imposed protocol.