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 cardiovascular system were determined in 10 elderly subjects [age 62 +/- 2 yr, pretraining maximal oxygen consumption (VO2 max)/kg = 25 +/- 2 ml . min-1 . kg-1 body wt]. They trained on a cycloergometer 3 times/wk for 16 wk (50-80% VO2 max, then 80-85% VO2 max). They were checked at 8 wk, 16 wk, and 4 mo after detraining. Training improved VO2 max (+16%) and induced plasma volume expansion (+11%). No change in total body water, extracellular 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 increased fractional shortening and ejection fraction and decreased left ventricular end-systolic dimension (P < 0.05). Blood volume expansion correlates with cardiac contractility and has an impact on cardiac function. These improvements are precarious, however, and are completely lost after 4 mo of detraining, when elderly subjects lose the constraints and the social stimulation of the imposed protocol.