Effects Of Lifestyle Modifications On Serum Testosterone Levels In Overweight And Obese Men: 3691 Board #138 June 3 9

PURPOSE: Testosterone is associated with lots of physiological functions in men. Obesity results in reduced serum testosterone levels in men. Previously, we demonstrated that combination of dietary modification and regular aerobic exercise increased serum testosterone levels in overweight/obese men. However, the differences in the effects on serum testosterone levels between dietary modification and regular aerobic exercise are unknown. The aim of this study was to compare the effects of dietary modification and regular aerobic exercise on serum testosterone levels in overweight/obese men. METHODS: Twenty-four overweight/obese men completed 12-week dietary modification class (well balanced 1680 kcal/day diet: diet group) and twenty-seven overweight/obese men completed 12-week regular aerobic exercise intervention (1-3 days/week, 40-60 min/day: exercise group). Before and after the intervention, we measured serum testosterone levels in overweight/obese men. RESULTS: At baseline, there were no significant differences in all parameters between both groups. Body mass was significantly decreased in both groups (both P < 0.01), and the magnitude of weight loss was greater in diet group than exercise group (−7.8 ± 2.0 % vs. −2.1 ± 0.6 %, P < 0.01). While, serum testosterone levels were significantly increased only in exercise group, and we found a significant difference in the percentage change in serum testosterone level (diet group: −0.3 ± 8.6 %, exercise group: 11.6 ± 3.1 %, P < 0.01). Moreover, in diet group, we found a significant correlation between percentage change in body mass and that in serum testosterone levels (r = −0.77, P < 0.001), but not in exercise group (r = −0.16, n.s.). CONCLUSIONS: We demonstrated regular aerobic exercise significantly increased serum testosterone levels, while dietary modification did not change serum testosterone levels in overweight/obese men. Moreover, percentage change in serum testosterone levels did not correlate to that in body mass in exercise group. Thus, these results suggest that regular aerobic exercise increases serum testosterone levels independent of the change in body mass in overweight/obese men. These findings may provide a new insight into the role of regular aerobic exercise for prevention and/or treatment of obesity-induced health disorders.