Does exercise beneficially affect sex hormones when added to hypo-caloric diets in adults with overweight or obesity? A systematic review and meta-analysis of controlled clinical trials.

OBJECTIVE: There is no consensus of opinion if exercise beneficially affects sex hormones if added to weight-loss diets. The purpose of this study was to perform a systematic review and meta-analysis of controlled clinical trials to evaluate the effect of adding exercise to a hypo-caloric diet during a weight-loss program, on serum testosterone, estradiol, and sex hormone-binding globulin (SHBG) in adults with overweight/obesity. DESIGN: Systematic review and meta-analysis of the literature. METHODS: Online databases including PubMed/MEDLINE, EMBASE, Scopus, ISI Web of Science, and Google Scholar were searched up to April 2021. A random-effects model was applied to compare mean changes in sex hormones and SHBG between participants undergoing a hypo-caloric diet with or without exercise. RESULTS: In total, 9 eligible clinical trials with 462 participants were included. Out of these, seven, three, and four studies illustrated changes in testosterone, estradiol, and SHBG, respectively. The meta-analysis revealed that exercise had no significant effect on circulating testosterone (WMD = -0.03 nmol/L, 95% CI: -0.11, 0.06, P = 0.51), estradiol (WMD = -0.46 pg/mL, 95% CI: -1.57, 0.65, P = 0.42), and SHBG (WMD = 0.54 nmol/L, 95% CI: -2.63, 3.71, P = 0.74) when added to low-calorie diets. CONCLUSION: The addition of exercise to a hypo-caloric diet provided no additional improvement in sex hormone profiles. Further, well-designed randomized controlled trials with longer follow-up periods in both sexes are recommended to confirm and expand the current results.