Plasma and salivary steroid hormone responses of men to high-intensity cycling and resistance exercise

Abstract

Hormonal responses to exercise could be used as a marker of overreaching. A short exercise protocol that induces robust hormonal elevations in a normal trained state should be able to highlight hormonal changes during overreaching. This study compared plasma and salivary cortisol and testosterone responses to 4 exercise trials; these were (a) continuous cycle to fatigue at 75% peak power output (Wmax) (FAT); (b) 30-minute cycle alternating 1-minute 60% and 1 minute 90% Wmax (60/90); (c) 30-minute cycle alternating 1-minute 55% and 4-minute 80% Wmax (55/80); and (d) Squatting 8 sets of 10 repetitions at 10 repetition maximum (RESIST). Blood and saliva samples were collected pre-exercise and at 0, 10, 20, 30, 40, 50, and 60 minute postexercise. Pre- to postexercise plasma cortisol increased in all exercise trials, except 60/90. Increases in 55/80 remained above pre-exercise levels for the entire postexercise period. Salivary cortisol increased from pre- to postexercise in FAT and 55/80 trials only. Once elevated after 55/80, it remained so for the postexercise period. Plasma testosterone increased from pre- to postexercise in all trials except 55/80. Saliva testosterone increased from pre- to postexercise in all trials with the longest elevation occurring after 55/80. Area under the curve analysis indicated that the exercise response of salivary hormones was greater in all cycle trials (cortisol) and in the 60/90 and 55/80 trials (testosterone) compared with the other trials. This study indicates that the 55/80 cycle protocol induces a prolonged salivary and plasma cortisol and salivary testosterone response compared with the other trials and so may be a useful diagnostic tool of overreaching.