Serum cortisol response to incremental work in experienced and naive subjects.

Twelve experienced and seven naive male subjects with a similar Vo2max, performed an incremental work test on an electronically braked bicycle until exhaustion. High venous lactate concentrations were recorded in both groups (naive-11.74 +/- 2.43, experienced-13.96 +/- 2.36 mmol/liter). No significant relationship could be demonstrated between Vo2max, venous lactate concentration, Borg ratings of perceived exertion, and the serum cortisol response. The postexercise increase in serum cortisol was significant in both experienced (59%) and naive (138%) groups, and was significantly greater in the naive as compared to the experienced subjects. The present results indicate that the psychoendocrine response to a novel situation was a major determinant of the serum cortisol response to maximum work.