Salivary and Serum Concentrations of Cortisol and Testosterone at Rest and in Response to Intense Exercise in Boys Versus Men

Abstract

This study compared salivary and serum concentrations of testosterone and cortisol at rest and in response to intense multitask exercise, in boys and men. Early morning saliva and venous blood samples were obtained pre- and 15 min post-exercise from 30 competitive swimmers (15 boys, 14.3±1.9y; 15 men, 21.7±3.1y). Exercise included a swim-bench maximal strength task, an all-out 200m swim, followed by a high-intensity interval swimming protocol (5 x 100m, 5 x 50m, and 5 x 25m). At baseline, fasting testosterone (but not cortisol) concentration was higher in men than boys in serum and saliva (p<0.05). Salivary and serum cortisol increased post-exercise, with a greater increase in men compared with boys (men: 226% and 242%, respectively, boys: 78% and 64%, respectively; group-by-time interaction, p<0.05). Testosterone was reduced post-exercise in serum but not in saliva (men: -14.7% and 0.1%, respectively, boys: -33.9% and - 4.5%, respectively, fluid-by-time interaction, p<0.01). Serum and salivary cortisol (but not testosterone), pre- and post-exercise values were strongly correlated in both men and boys (r=0.79 and 0.82, respectively; p<0.01). In summary, early morning high-intensity exercise results in a decrease in testosterone in serum, but not saliva, and an increase in cortisol irrespective of the fluid used, in both boys and men. When examining immediate post-exercise changes, the lack of correlation in testosterone between saliva and serum suggests that saliva may not be an appropriate fluid to examine changes in testosterone. The high correlation observed between serum and saliva for cortisol indicates that, in both boys and men, saliva may be used to monitor the immediate cortisol response to exercise.