Overreaching, a consequence of intensified training, is used by athletes to enhance performance. A blunted hormonal response to a 30-min interval exercise stress test (55/80) has been shown in males after intensified training, highlighting cortisol and testosterone as potential biomarkers of overreaching. Despite accounting for ~50% of the population, studies into hormonal responses to exercise in females are lacking. The menstrual cycle and oral contraceptives profoundly affect hormonal responses, necessitating separate investigations into the female response to the same exercise-stress test. On three separate visits, 13 females (6 oral contraceptive users, 7 eumenorrheic) completed a VO2max test, resting control trial, and 55/80 stress test. The 55/80 involves alternating between 1 min at 55% VO2max and 4 min at 80% VO2max. Blood and saliva were collected pre, post, and 30 min post-55/80, and at coinciding time points during the resting control trial. Plasma progesterone, estrogen, and plasma and salivary cortisol and testosterone were analyzed via ELISA. A significant elevation of salivary and plasma cortisol (~141% and ~87%, respectively, p < 0.001), salivary testosterone (~93%, p < 0.001), and plasma progesterone (~58%, p = 0.004) were evident from pre- to post-55/80. Plasma testosterone remained unchanged. Hormonal responses were attenuated in oral contraceptive users. The 55/80 induces hormonal elevations in females, similar in magnitude as males.
Keywords: biomarker; female; hormone; intensified training; overreaching.
© 2024 The Author(s). Physiological Reports published by Wiley Periodicals LLC on behalf of The Physiological Society and the American Physiological Society.