Oral estrogen therapy may mitigate the effects of aerobic training on cardiorespiratory fitness in postmenopausal women

Abstract

The aim of this study was to evaluate the isolated and associated effects of oral estrogen therapy and aerobic training on cardiorespiratory fitness in postmenopausal women. Forty-two hysterectomized healthy postmenopausal women were randomly divided (in a double-blind manner) into four groups: placebo-control (n = 9), estrogen therapy-control (n = 12), placebo-aerobic training (PLA-AT; n = 11), and estrogen therapy-aerobic training (ET-AT; n = 10). The estrogen therapy groups received estradiol valerate (1 mg/day) and the aerobic training groups trained on a cycle ergometer three times per week at moderate intensity. Before and 6 months after the interventions, all women underwent a maximal cardiopulmonary exercise test on a cycle ergometer. Regardless of hormone therapy, aerobic training increased oxygen uptake at anaerobic threshold (P = 0.001), oxygen uptake at respiratory compensation point (P = 0.043), and oxygen uptake at peak exercise (P = 0.020). The increases at respiratory compensation point and peak exercise were significantly greater in the groups receiving placebo than in the groups receiving estrogen (oxygen uptake at respiratory compensation point: PLA-AT +5.3 [2.8] vs ET-AT +3.0 [2.5] mL kg(-1) min(-1), P = 0.04; oxygen uptake at peak exercise: PLA-AT +5.8 [3.4] vs ET-AT +2.8 [1.4] mL kg(-1) min(-1), P = 0.02). Oral estrogen therapy may mitigate the cardiorespiratory fitness increase induced by aerobic training in hysterectomized healthy postmenopausal women.