BASAL REPRODUCTIVE HORMONAL PROFILES ARE ALTERED IN ENDURANCE-TRAINEDMEN

Objective. The purpose was to examine the basal reproductive hormonal profiles in age-matched groups of endurance trained (ET) and sedentary (SED) men under controlled conditions. Experimental design. Resting b asal blood samples were obtained from groups of ET and SED men after a 24-hr control period. Blood specimens were analyzed for testosterone (T), free-testosterone (fT), sex-hormone binding globulin (SHBG), lute inizing hormone (LH), cortisol, and prolactin. The design of the study was retrospective and cross-sectional in nature. Setting. Laboratory setting at the University of North Carolina, North Carolina USA. Parti cipants. ET men (n=53) who had been involved with chronic endurance ex ercise training for greater than or equal to 5 years. SED men (n=35) w ere selected of comparable ages and the fact that they had done no for mal exercise training. Results. Results indicated that the basal T and fT of the ET men were significantly (p<0.01) lower than that of the S ED men. The levels of these hormones in the ET men where in the normal clinical range, but represented only 55% to 85% of those seen in the SED men. For SHBG, LH, cortisol, and prolactin, no significant differe nces (p>0.05) were found between the ET and SED men. Conclusions. ET m en have lowered basal T and fT levels and this suppression may be rela ted to an alteration in the hypothalamic-pituitary-testicular regulato ry axis since the LH of the ET was not elevated. Whether these hormona l changes have any significant beneficial(i.e., protective cardiovascu lar) or negative (i.e., decrease anabolic-androgenic processes) physio logic consequences remains to be determined.