[The effect of physical exercise on the response to exertion in the elderly]

A decrease in adaptation to exertion has been observed as age progresses. Although this decline may also be affected by factors such as health conditions and age, physical inactivity related to sedentary behaviour plays a dominant role.

In order to evaluate the influence of physical activity on cardiovascular response to exertion in the elderly, 4 groups of 22 subjects each were submitted to maximal electrocardiographic exercise test on a cycloergometer (multistage program with 30 Watts x 3 min. steps). All subjects were male. The composition of the groups was as follows: 1) veteran long distance runners (mean age: 71 +/- 5.4); 2) sedentary veterans (mean age: 69.8 +/- 3.9); 3) young long distance runners (mean age: 25.4 +/- 4.3); 4) sedentary young adults (mean age: 25.8 +/- 3.9). The endurance athletes, well fitted to competition, had been practicing sport activity for at least 3 years.

Heart rate, arterial systolic and diastolic blood pressure were recorded; mean blood pressure and double product were calculated at baseline and at the climax of the stress test; furthermore, total and maximal watts were recorded. For each of the parameters, Student's t test for non-paired observations were used to evaluate statistical differences amongst the four groups. The most interesting result arises in the comparison between veteran long distance runners and sedentary young adults: between the two groups no statistically significant differences in workload, expressed as total watts (1649.55 +/- 296.32 vs 1650.00 +/- 446.32; p = NS) and maximal watts (175.91 +/- 19.19 vs 173.18 +/- 24.38; p = N.S.), were observed. On the contrary, highly significant differences in both total (p < 0.01) and maximal (p < 0.01) watts were noticed by comparing long distance runners and sedentary subjects of the same age.

These data support the hypothesis that the progressive reduction in physical activity, which is usually observed in aging, is the major determinant of exercise deconditioning in the elderly.