Prolonged exercise increases peripheral plasma ACTH, CRH, and AVP in male athletes

Abstract

We wished to determine whether the increased ACTH during prolonged exercise was associated with changes in peripheral corticotropin-releasing hormone (CRH) and/or arginine vasopressin (AVP). Six male triathletes were studied during exercise: 1 h at 70% maximal oxygen consumption, followed by progressively increasing work rates until exhaustion. Data obtained during the exercise session were compared with a nonexercise control session. Venous blood was sampled over a 2-h period for cortisol, ACTH, CRH, AVP, renin, glucose, and plasma osmolality. There were significant increases by ANOVA on log-transformed data in plasma cortisol (P = 0.002), ACTH (P < 0.001), CRH (P < 0.001), and AVP (P < 0.03) during exercise compared with the control day. A variable increase in AVP was observed after the period of high-intensity exercise. Plasma osmolality rose with exercise (P < 0.001) and was related to plasma AVP during submaximal exercise (P < 0.03) but not with the inclusion of data that followed the high-intensity exercise. This indicated an additional stimulus to the secretion of AVP. The mechanism by which ACTH secretion occurs during exercise involves both CRH and AVP. We hypothesize that high-intensity exercise favors AVP release and that prolonged duration favors CRH release.