Age attenuated response to aerobic conditioning in postmenopausal women.

The decline in aerobic capacity does not appear to be linear across age. To explore this relationship, we examined the maximal cardiorespiratory response of 251 postmenopausal women to 6 months of exercise training: control (no exercise), or exercise at 4, 8, or 12 kcal/kg/week (KKW). Exercise intensity was set at a heart rate associated with 50% of peak VO(2peak) and women were stratified by age into three groups: <55 years, 55-59 years, >60 years. Differences in outcomes among groups were tested by ANOVA and the results were presented as adjusted least squares means with confidence intervals. At baseline participants who were >60 years had a lower VO(2peak) than those <55 years [mean (SD) 1.44 (0.24) vs. 1.20 (0.20) L/min, P < 0.04). Following exercise training, we observed an attenuated training response due to age within the 8 and 12 KKW groups (both, P for trend 0.001). For the 8 KKW group, changes in VO(2peak) were [mean, (95% CI)]: <55 years [0.18 (0.12, 0.24) L/min], <55 years, 55-59 years [0.08 (0.02, 0.15) L/min], and >60 years [0.02 (-0.03, 0.08)]. For 12 KKW group, the changes were: <55 years [0.19 (0.15, 0.24) L/min], 55-59 years [0.13 (0.08, 0.18) L/min], and >60 years [0.05 (-0.01, 0.10)]. Our data show that despite similar exercise intensities, age plays a significant role in the maximal cardiorespiratory response to exercise training regardless of training volume in women who have completed menopause.