Effect of exercise on serum sex hormones in men: A 12-month randomized clinical trial. Med Sci Sports Exerc

Purpose—The effect of exercise on androgens in middle-aged to older men is poorly understood, and it could have implications for several aspects of health. This analysis was conducted to examine the effects of long-term aerobic exercise on serum sex hormones in middle-aged to older men. Methods—One hundred two sedentary men, ages 40–75 yr, were randomly assigned to a 12-month exercise intervention or a control group (no change in activity). The combined facility- and home-based exercise program consisted of moderate/vigorous-intensity aerobic activity for 60 min·d−1, 6 d·wk−1. Serum concentrations of testosterone, free testosterone, dihydrotestosterone (DHT), 3α-androstanediol glucuronide (3α-Diol-G), estradiol, free estradiol, and sex hormone– binding globulin (SHBG) were measured at baseline, 3, and 12 months. Results—Exercisers trained a mean of 370 min·wk−1 (102 % of goal), with only two dropouts. Cardiopulmonary fitness (V̇O2max) increased 10.8 % in exercisers and decreased by 1.8 % in controls (P < 0.001). DHT increased 14.5 % in exercisers versus 1.7 % in controls at 3 months (P = 0.04); at 12 months, it remained 8.6 % above baseline in exercisers versus a 3.1 % decrease i