Maximal and submaximal aerobic fitness in postmenopausal women: influence of hormone-replacement therapy

The purpose of this study was to examine whether maximal and submaximal aerobic fitness parameters ( peak oxygen consumption and ventilatory threshold, respectively) are affected by hormone-replacement therapy (HRT) in moderately active postmenopausal women. Forty healthy, active, postmenopausal women ( 21 taking HRT, mean age 62 +/- 5 years; 19 not taking HRT, mean age 62 +/- 7 years) met the peak oxygen consumption criteria during a cycle ergometer test ( 15 W ramp) and achieved volitional fatigue. Breath-by-breath measurement was used to determine peak oxygen consumption and to estimate ventilatory threshold. There were no differences in characteristics ( age, body mass, height, body mass index, leisure-time physical activity) between the non-HRT and HRT groups, nor were there any differences in responses to maximal exercise, with an observed peak oxygen consumption (mL.kg(-1) min(-1)) of 22.9 +/- 3.8 in the non-HRT group and 22.0 +/- 4.7 in the HRT group. There was also no difference in submaximal aerobic capacity, with ventilatory threshold values (mL.kg(-1) min(-1)) of 16.7 +/- 3.4 in the non-HRT group and 15.6 +/- 3.2 in the HRT group. In a sample of healthy moderately active postmenopausal women, there was no difference in maximal or submaximal aerobic fitness parameters beteen the HRT and non-HRT groups.