This study examined the influence of 10 days of intensified training on salivary cortisol and testosterone responses to 30-min, high-intensity cycling (55/80) in a group of male elite triathletes.
Seven elite male triathletes (age 19 ± 1 y, V̇O2max 67.6 ± 4.5 mL · kg–1 · min–1) completed the study. Swim distances increased by 45%. Running and cycling training hours increased by 25% and 229%, respectively. REST-Q questionnaires assessed mood status before, during, and after the training period. Unstimulated saliva samples were collected before, after, and 30 min after a continuous, high-intensity exercise test. Salivary cortisol and testosterone concentrations were assessed.
Compared with pretraining, blunted exercise-induced salivary testosterone responses to the posttraining 55/80 were found (P = .004). The absolute response of salivary testosterone concentrations to the 55/80 decreased pretraining to posttraining from 114% to 85%. No changes were found in exercise-induced salivary cortisol concentration responses to the 55/80. REST-Q scores indicated no changes in the participants’ psychological stress–recovery levels over the training camp.
The blunted exercise-induced salivary testosterone is likely due to decreased testicular testosterone production and/or secretion, possibly attributable to hypothalamic dysfunction or reduced testicular blood flow. REST-Q scores suggest that the triathletes coped well with training-load elevations, which could account for the finding of no change in the exercise-induced salivary cortisol concentration. Overall, these findings suggest that the 55/80 can detect altered exercise-induced salivary testosterone concentrations in an elite athletic population due to increased training stress. However, this alteration occurs independently of a perceived elevation of training stress.