Effects of "lifelong" physical training on functional aging in men.

Functional aging was examined in a cross-sectional study of 22 habitually trained and 22 sedentary men (aged 34 to 70 and 33 to 68, respectively) by using various physiological, psychophysiological, and anthropometric measurements. Compared to the control group, the trained subjects had significantly higher maximal oxygen uptake, vertical velocity, maximal breathing capacity, percentage of slow twitch muscle fibers, and muscle isocitrate dehydrogenase activity, in addition to lower values in body weight, systolic as well as diastolic blood pressure, patellar reflex time, serum triglycerides, and fast twitch muscle fibers (particularly glycolytic fibers). The results showed that the effects of endurance training are largely limited to functions which are apparently relevant to physical performance. The age regression lines were parallel or as in some of the variables influenced by training, even slightly steeper for the trained versus the untrained group. It is suggested that the aging process itself is not retarded by habitual physical training. Great differences between the two groups in muscle fiber composition and maximal oxygen uptake indicate that endurance-active people are also selected on the basis of inherited structural and functional properties.