Plasma variations in testicular and adrenal androgens during prolonged physical exercise in man.

The evolution of the relationship between cortisol and testicular androgens was verified on two teams of respectively 10 and 9 male subjects (average age 34) running 100 km races in an average time of 14 hours. When compared to a control population of the same age, these trained athletes exhibited reduced testicular androgen levels (T and DHT) and increased adrenal androgen (delta 4) and cortisol levels with no significant alteration of LH. The period of recovery is characterized by rapid return to normal of the hormonal parameters whereas testosterone levels continue to increase in the following days. This hormonal picture, which reappears under certain pathological situations or when subjects are exposed to heavy stresses, seems to prove that the testicular androgens could be, both by their metabolic and psychic action, one of the limiting factors of physical aptitude to sustained effort.