Background
Testosterone levels and physical activity (PA) each play important roles in men’s health, but the relationship between the two remains unclear.
Methods
We evaluated the cross-sectional association between self-reported total PA and serum testosterone levels in 738 men (mean age 42.4 yrs, range 20-≥85yrs) who participated in NHANES 1999–2004. We compared geometric mean testosterone concentrations measured by RIA and calculated the odds ratio (OR) of having low or low normal testosterone (≤3.46 ng/mL) across tertiles of total PA in all men, and men stratified by age (20–49, ≥ 50 years), and obesity status (BMI <30, ≥ 30 kg/m2).
Results
The geometric mean testosterone concentration was 5.31 ng/mL; 18.6% of the men had low or low normal serum testosterone levels. PA tertiles were not associated with testosterone levels overall, or when stratified by age or obesity status. Similarly, there was no association between PA tertiles and the odds of low or low normal testosterone, overall or by age. However, among non-obese men, those in the highest PA tertile were significantly less likely to have low or low normal testosterone than those in the lowest tertile (OR 0.50; 95% CI = 0.26–0.95); there was no association among obese men.
Conclusions
Greater PA was not associated with testosterone levels, but may be associated with a reduced odds of low or low normal testosterone in non-obese men, but not in obese men.