Effect of long-term physical training on plasma testosterone, androstenedione, luteinizing hormone and sex-hormone-binding globulin capacity.

The effect of 6-months' physical training on plasma testosterone, androstenedione and luteinizing hormone levels and the binding capacity of sex-hormone-binding globulin (SHBG capacity) were studied in thirty-nine army recruits. Highly significant increases in mean plasma testosterone (21%), androstenedione (25%) and LH (25%) were observed during the training period and were associated with a mean 16% increase in the estimated maximal oxygen uptake. The mean increases in hormone levels tended to be greater in the well conditioned group than in the poorly conditioned group. The mean ratio of testosterone to SHBG capacity increased by 32% (P less than 0.05), which may be in relationship with the various training-induced effects.