Effects of Exercise Training on Resting Testosterone Concentrations in Insufficiently Active Men: A Systematic Review and Meta-Analysis

Potter, NJ, Tomkinson, GR, Dufner, TJ, Walch, TJ, Roemmich, JN, Wilson, PB, and Fitzgerald, JS. Effects of exercise training on resting testosterone concentrations in insufficiently active men: a systematic review and meta-analysis. J Strength Cond Res 35(12): 3521-3528, 2021-The anabolic hormone testosterone plays a pivotal role in the healthy aging of men and tends to decline with age. The aims of this systematic review and meta-analysis were 2-fold: (a) to evaluate the effect of exercise training on resting total testosterone concentration in insufficiently active, apparently healthy men and (b) to determine whether the effects of exercise training differed by training mode, age, body mass status, or testosterone measure. Electronic databases (MEDLINE, Scopus, CINAHL, and SPORTDiscus) were systematically searched (up to and including October 22, 2020) for peer-reviewed randomized controlled trials (RCTs) meeting the following criteria: population (insufficiently active, apparently healthy men aged >= 18 years), intervention (exercise training [any modality at intensity of >= 4 metabolic equivalents] lasting a minimum of 4 weeks), control (insufficiently active men), and outcome (resting total testosterone concentration). Intervention effects, weighted by the inverse of the pooled variance, were calculated relative to the control group as standardized mean differences (SMDs). Eleven RCTs, representing 421 insufficiently active, apparently healthy men aged 19-75 years across 16 intervention groups who participated in aerobic, resistance, or combined training lasting a median of 12 weeks, were included in the analysis. Overall, exercise training had a negligible effect on resting total testosterone concentration (mean SMD [95% CI]: 0.00 [-0.20 to 0.20]). Subgroup analyses indicated that the effect of exercise training was not significantly affected by training mode, age, body mass status, or testosterone measure. Exercise training does not seem to affect resting total or free testosterone concentration in insufficiently active, eugonadal men.