RELATIONSHIPS BETWEEN TESTOSTERONE, CORTISOL AND PERFORMANCE IN PROFESSIONAL CYCLISTS

In the literature the use of plasma levels of cortisol and the testost erone and testosterone:cortisol ratio for training management is encou raged. Decreased levels of testosterone and increased levels of cortis ol are suggested to be indicative for a disturbance in the anabolic-ca tabolic balance, which may express itself in decreased performance. Th e purpose of the study was to examine if the acute hormonal response t o a bout of exercise and the resting levels of testosterone, luteinizi ng hormone (LH) and cortisol are correlated to performance in cyclists . In addition,the effect of training on this correlation was studied. Ten professional cyclists participated and measurements took place bef ore and after a defined period of training. Maximum workload (Pmax), d etermined on a cycle-ergometer with a slowly increasing protocol, incr eased by 30 watt (p < 0.001). Workload ata lactate level of 4 mmol/l ( P4) increased by 18 watt (p < 0.05). Post training, resting testostero ne levels decreased from 28.8 +/- 74 nmol/l to 24.6 +/- 90 nmol/l (p < 0.05), Resting cortisol levels increased from 272 +/- 110 nmol/l pre training to 379 +/- 242 nmol/l post training (p < 0.05). These results indicate an increased catabolic state. The acute hormonal response an d the resting levels of LH were not changed post training, The resting levels of testosterone and cortisol and the acute response to exercis e showed no correlation with performance pre and post training. In spi te of an increased catabolic state post training there was an increase in performance, These results suggest that in endurance trained cycli sts, decreased testosterone levels, increased cortisol levels and a de creased testosterone:cortisol ratio does not automatically lead to a d ecrease in performance or a state of overtraining.