Glucocorticoid response to exercise as measured by serum and salivary cortisol

Summary Serum and salivary cortisol concentrations were studied in 78 elite athletes engaged in different sports, by subjecting them to high-intensity laboratory exercise. The mean difference in the pre-exercise cortisol concentrations in the seven groups studied were more marked in serum (from 311 to 768 nmol · l^–1) than in saliva (from 17.9 to 22.7 nmol · 1^–1, only one group reaching 40 nmol ·^–1). Judging from the correlation coefficients based on total variances, the post-/pre-exercise differences in cortisol concentrations in serum depended chiefly on pre-exercise values, while those in saliva tended to depend more on the postexercise concentrations. The coefficients of correlation between that difference and either the pre- or postexercise values were –0.71 and 0.47, respectively, for serum, and –0.51 and 0.58, respectively, for saliva. This would suggest that salivary cortisol concentration might be a more suitable variable for assessing glucocorticoid activity in exercise than serum cortisol concentration, probably being less sensitive to pre-exercise emotional state.