Aerobic exercise training in healthy postmenopausal women: effects of hormone therapy

OBJECTIVE: We investigated the influence of hormone therapy (HT) on submaximal central and peripheral function in healthy postmenopausal women after 12 weeks of endurance training. METHODS: A randomized, double-blind, placebo-controlled study in a research and clinical facility was conducted. All participants (N = 23) underwent 12 weeks of aerobic exercise training (walking 5 d/wk at 70%-80% peak heart rate [HR]). Eleven participants received HT; 12 received placebo. HT consisted of daily 17beta-estradiol (1 mg) with cyclic micronized progesterone (200 mg) or placebo for 10 days per month. Participants were tested before and after exercise training. Primary outcome measures were submaximal stroke volume, cardiac output, and total peripheral resistance measured during cycling at 30W, 45W, and 60W. Secondary outcome measures were ventilatory threshold, peak oxygen uptake (VO2 peak), and resting and peak-ischemic calf blood flow. RESULTS: At baseline, HT and placebo groups were similar (P > 0.05) in age (mean +/- SEM, 57 +/- 1 y), height (162 +/- 2 cm), weight (72 +/- 4 kg), VO2 peak (21.5 +/- 1.4 mL . kg . min), and all cardiovascular measures. Posttraining oxygen consumption and HR decreased (P < 0.05) within groups during each submaximal exercise workload. Stroke volume, cardiac output, and total peripheral resistance remained unaltered (P > 0.05). VO2 peak and oxygen consumption at the ventilatory threshold increased (P < 0.05) within groups. Resting and postischemic blood flow were unaltered. HT did not influence any of the cardiovascular responses. CONCLUSIONS: These findings suggest that in healthy postmenopausal women, 12 weeks of aerobic training is effective in eliciting favorable cardiovascular adaptations, regardless of the presence of short-term HT.