Lifestyle modification-induced increase in serum testosterone and SHBG decreases arterial stiffness in overweight and obese men

Background: Arterial stiffness-a risk factor for cardiovascular diseases-is more frequently observed in obese men. Moreover, the male sex hormone testosterone has an anti-atherogenic effect. Serum testosterone levels are found to be lower in obese men than in age-matched normal-weight men. However, the effect of lifestyle modification on testosterone in obese men has not been elucidated. Here, we examined the effect of lifestyle modifications on serum testosterone levels and arterial stiffness in overweight and obese men. Methods: Eleven overweight and obese men (mean age: 53 ± 3 years) completed a 12-week lifestyle modification program. Before and after the program, we measured the mean blood pressure (MBP), carotid-femoral pulse wave velocity (cfPWV; as an index of arterial stiffness), and the serum total testosterone levels in all participants. Results: We observed a significant weight loss after the 12-week lifestyle modification program. After the program, MBP and cfPWV significantly decreased and serum testosterone levels significantly increased. Moreover, we observed a negative relationship between the change in serum testosterone levels and that in cfPWV, although this relationship was affected by change in MBP. Conclusions: Lifestyle modification increased the serum testosterone levels in overweight and obese men. The increase in serum testosterone levels was associated with a corresponding reduction in MBP and arterial stiffness. These results suggest that an increase in the testosterone levels may be an important mechanism underlying the beneficial effect of lifestyle modification on arterial stiffness. However, the association may not be direct, but may be mediated by a change in the MBP.