RESUMO
OBJECTIVE: To compare the rate and magnitude of physiologic and psychologic adaptations to aerobic training between middle-age and older men, to assess their interest in continued participation (> 6 months) in a supervised high-intensity training program, and to evaluate the safety of high-intensity training for older people. DESIGN: Before-after intervention trial. SETTING: Medical center in a Midwestern metropolitan city. PARTICIPANTS: Thirteen middle-age (35-50 years) and 14 older (60-71 years) normal men. INTERVENTION: Subjects trained on treadmills and leg cycle ergometers for 40 minutes 3 times per week. The intensity was increased to 85% of peak heart rate (HR) within the first 3 weeks of training. MEASUREMENT: Peak oxygen consumption, HR at submaximal work rates, three psychological tests, and election to continue in the supervised program. RESULTS: At 6 months of training, peak oxygen consumption had increased by 12% and 11% in the middle-aged and older groups, respectively, with 86% and 100% of this increase occurring within the first 3 months. Both groups showed comparable decreases in HR at submaximal work rates after 3 months of training with no further significant change from 3 to 6 months. None of the psychologic parameters evaluated changed significantly with 3 or 6 months of training in either group. More of the older (71%) than middle-aged (45%) men elected to continue in the supervised program after 6 months. CONCLUSIONS: The results of this study involving small groups of carefully screened middle-aged and older men suggest that the time course and magnitude of physiologic adaptations to aerobic training are similar between age groups when the training regimen is the same. Neither age group showed alterations in psychologic parameters nor experienced orthopedic injuries with training. The older group showed greater interest in continued participation in a supervised exercise program.