REPRODUCIBILITY OF LOW RESTING TESTOSTERONE CONCENTRATIONS IN ENDURANCE-TRAINED MEN

Previous reports indicate endurance trained (ET) men have low resting testosterone concentrations without any significant increases in their luteinizing hormone (LH) concentrations. The purpose of this study wa s to examine the reproducibility of these resting hormonal findings in ET men. Resting blood samples were collected at three separate trials (2 weeks apart) in groups of ET men (n = 15) and age-matched, untrain ed (UT, n = 13) men. Blood specimens were analyzed for total testoster one, LH, cortisol and prolactin. Results indicated that testosterone w as significantly (p < 0.01) lower in ET than UT at each of the three t rials. LH, cortisol, and prolactin were not different (p > 0.05) betwe en the groups at any trial. These results confirm earlier findings rep orted for ET men. Furthermore, the results indicate the resting reprod uctive hormonal status (i.e., low testosterone) of ET men is reproduci ble and does not appear to be an artifact of the timing of the blood s ampling methodology used.