Introduction: Obesity and inactivity are associated with erectile dysfunction and hypogonadism.

Aim: To compare the effects of low volume (LV) and high volume (HV) of moderate-intensity exercise on sexual function, testosterone, lower urinary tract symptoms (LUTS), endothelial function, and quality of life (QoL) in obese men.

Main outcome measures: Weight, waist circumference (WC), body composition, International Index of Erectile Function 5-item (IIEF-5), International Prostate Symptom Scale (IPSS) (for LUTS), and 36-item Short Form Survey version 2 Instrument (SF-36) (for QoL) scores, plasma testosterone, sex-hormone binding globulin, glucose, insulin and lipids, and endothelial function (by Reactive Hyperaemia Index [RHI] using finger plethysmography) were measured at baseline and 24 weeks.

Methods: Ninety abdominally obese (body mass index > 27.5 kg/m(2), WC > 90 cm), sedentary (exercise ≈ 80 minutes/week) Asian men (mean age 43.6 years, range 30-60) were prescribed a diet to reduce daily intake by ≈ 400 kcal below calculated requirement and randomized to perform moderate-intensity exercise of LV (<150 minutes/week) or HV (200-300 minutes/week) (n = 45 each) for 24 weeks. Seventy-five men (83.3%) completed the study.

Results: Weekly exercise volume was significantly greater in the HV (236 ± 9 minutes) than the LV (105 ± 9 minutes) group. The HV group had significantly greater increases in IIEF-5 score (2.6 ± 0.5 points) and testosterone (2.06 ± 0.46 nmol/L) and reductions in weight (-5.9 ± 0.7 kg, -6.2%), WC (-4.9 ± 0.8 cm, -4.9%), and fat mass (-4.7 ± 1.0 kg, -14.5%) than the LV group (-2.9 ± 0.7 kg, -3.0%; -2.7 ± 0.7 cm, -2.5%; -1.1 ± 0.8 kg, -3.2%; 0.79 ± 0.46 nmol/L; and 1.8 ± 0.5 points). Improvements in IPSS and SF-36 scores, and RHI, were similar.

Conclusions: Moderate-intensity HV aerobic exercise > 200 minutes/week produces greater improvements in sexual function, testosterone, weight, WC, and fat mass than smaller exercise volume.