Effects of estrogen therapy and aerobic training on sympathetic activity and hemodynamics in healthy postmenopausal women: a double-blind randomized trial.

Objective: The aim of this study was to evaluate the isolated and associated effects of aerobic training and estrogen therapy on sympathetic nerve activity and hemodynamics in healthy postmenopausal women. Methods: Forty-five postmenopausal women (mean [SD] age, 51 [3] y) were randomly divided into four groups: sedentary-placebo (SED-PLA; n = 11), sedentaryYestrogen therapy (SED-ET; n = 14), aerobic trainingYplacebo (AT-PLA; n = 12), and aerobic trainingYestrogen therapy (AT-ET; n = 8). The ET groups received oral estradiol valerate (1 mg/d), whereas the PLA groups received placebo. The AT groups performed aerobic exercise three times a week on a cycle ergometer for 50 minutes, whereas the SED groups remained sedentary. All participants were evaluated before and after 6 months. Muscle sympathetic nerve activity (MSNA; microneurography), forearm blood flow (plethysmography), blood pressure (oscillometry), and heart rate (HR) were measured at rest for 10 minutes. Data were analyzed by three-way analysis of variance. Results: Estrogen administration itself did not change any of the studied parameters. AT improved forearm blood flow (AT-PLA, 2.02 [0.85] vs 2.92 [1.65] mL min j1 100 mL j1 , P = 0.03; AT-ET, 1.68 [1.11] vs 2.27 [0.76] mL min j1 100 mL j1 , P = 0.03), reduced MSNA in the AT-PLA group (39 [6] vs 34 [5] bursts/min, P = 0.01), and decreased HR in the AT-ET group (65 [8] vs 62 [7] beats/min, P =0 .01). Conclusions: AT reduces sympathetic nerve activity and improves muscle blood flow in healthy hysterectomized postmenopausal women. Moreover, AT decreases HR when combined with ET. However, ET abolishes the reducing effect of AT on MSNA.