Salivary and Serum Concentrations of Cortisol and Testosterone at Rest and in Response to Intense Exercise in Boys and Men
This study compared salivary and serum concentrations of testosterone and cortisol at rest and in response to high-intensity exercise, in boys and men. Early morning saliva and venous blood samples were obtained pre- and 15 min post-exercise from 31 competitive swimmers (15 boys, 14.3±1.8y; 16 men, 21.6±3.1y). Exercise included an all-out 200 m swim, followed by a high-intensity interval swimming protocol (5 x 100m, 5 x 50m, and 5 x 25m). Testosterone (but not cortisol) concentration was higher in men than boys in serum and saliva (p<0.05). Cortisol concentration was higher in serum compared with saliva (p<0.01). Salivary and serum cortisol increased post-exercise, with a greater increase in men compared with boys (group-by-time interaction, p<0.001). Serum testosterone declined post-exercise in serum but not in saliva (medium-by-time interaction, p<0.01). Serum and salivary cortisol (but not testosterone) were strongly correlated in both men and boys, as evidenced by the high intraclass correlation coefficients (ICC=0.86 and 0.90, respectively; p<0.001). 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 medium used, in both boys and men. The lack of correlation in testosterone between media suggests that saliva may not be an appropriate medium to examine changes in testosterone following intense exercise. The high ICC observed between serum and saliva cortisol indicates that, in both boys and men, saliva may be used to monitor the cortisol response to exercise.