Skenderi, K. P., Tsironi, M., Papastamataki, M., Moshoyianni, H., Kavouras, S. A., Papassotiriou, I., & Chrousos, G. (2008). Suppression and partial recovery of hypothalamic-pituitary-testicular axis hormones in ultraendurance athletes. ACSM 55th Annual Meeting Indianapolis, Presentation Number, 2483.

"In men, the hypothalamic-pituitary-testicular axis controls the secretion of testosterone, which is a major anabolic hormone. Physical exercise affects the entire axis and suppresses testosterone concentrations by complex, multilevel mechanisms. These involve hormones of the hypothalamic-pituitary-adrenal axis such as corticotropin-releasing hormone (CRH), beta-endorphin, and cortisol. After the exercise, the hypothalamic-pituitary-testicular axis recovers, however the time course and degree of recovery is not known. This is particularly relevant to the evaluation of athletes for possible doping when examined during and after a bout of strenuous exercise".

This study examined the influence of a long distance, endurance exercise on the hypothalamic-pituitary-adrenal axis and the secretion of testosterone. It was conducted to estimate their influence when evaluating athletes for doping. Males (N = 16) participating in the ultradistance foot race of the 246 Km “Spartathlon” (continuous, prolonged, brisk ambulation for up to 36 hours), were measured for circulating concentrations of testosterone, DHEAS, FSH, LH, and cortisol before and at the end of the race and 48 hours postrace.

Testosterone, FSH, and LH decreased dramatically at the end of the race, compared with before-race levels. Testosterone only partially recovered 48 hours postrace to about half the prerace values. The hypothalamic-pituitary-adrenal axis hormone DHEAS and cortisol levels increased significantly at the end of the race and returned to normal 48 hours postrace.

Implication. Observations of hypothalamic-pituitary-testicular axis hormones in ultramarathon runners, showed that prolonged exercise suppresses testosterone which remains partially suppressed for at least 48 hours, even after the hypothalamic-pituitary-adrenal axis recovered. This suggests that the type of exercise has a distinct pattern of hormonal response and recovery and should be taken into account when evaluating athletes for doping. The application of single value standards to all participants in all activities will lead to erroneous conclusions about doping-test results.

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