Stability and Variability in Hormonal Responses to Prolonged Exercise

Abstract

To study the dynamics of alterations in blood hormones and their individual variability during prolonged exercise, changes in plasma levels of corticotropin, cortisol, aldosterone, testosterone, progesterone, somatotropin, insulin and C-peptide were recorded in 32 endurance athletes and 50 untrained persons during a 2-hour exercise on a cycle ergometer at 60% VO2max. Common changes were activation of the pituitary corticotropin function, mostly at the end of exercise, rises in aldosterone and somatotropin concentrations and decreases in insulin and C-peptide levels during exercise. The activation of pituitary-adrenocortical system and the decrease of insulin but not C-peptide levels were more pronounced in athletes than in untrained persons. A large inter-individual variability existed in changes of cortisol, testosterone and progesterone in both groups. Five variants were found in the dynamics of cortisol concentration. Whereas the alterations of corticotropin were characterized mainly by a biphasic increase, the dynamics of corticotropin and cortisol coincided only in one variant out of five. Most characteristic for the postexercise recovery period were decreased activity of the pituitary-adrenocortical system and delayed normalization of aldosterone level.

Dexamethasone in resting and exercising men. II. Effects on adrenocortical hormones

“…Considering the fact that ACTH does not respond immediately at the onset of exercise (27,31), these theoretical values are certainly overestimated, and it is not surprising that in this study the cortisol level remained unchanged during exercise, because the delay necessary to obtain a significant response for cortisol was not reached. This may explain the controversial results found in the literature: some authors described a regular rise during the V O 2 max test (20); others reported a plateau, if not a fall, depending on individuals (30). In fact, the cortisol increase reported for all kinds of tests of short duration (Ͻ15 min) could simply arise from an anticipation stress, such as can be observed in situations of psychological stress without exercise (4).…”

“…For cortisol, which is the most reactive hormone after stress, postexercise levels can be twice as high as rest levels, as generally reported in the literature (20,30). To maintain such a level with a constant MCR, the PR must be doubled.…”

Acute changes in endocrine and fluid balance markers during high-intensity, steady-state, and prolonged endurance running: unexpected increases in oxytocin and brain natriuretic peptide during exercise

“…The statistically significant increase in the secretion of the mineralocorticoid hormone, [aldosterone] P , following all three running conditions is a welldocumented physiological response (39) (Fig. 2c).…”

Research Methodology: Endocrinologic Measurements in Exercise Science and Sports Medicine

“…A modified approach may be necessary, such as limiting recovery to 8 or 12 hours, somewhat preventing stress and anxiety (which, as noted earlier, can themselves affect the endocrine system) as a result of missing less training time. 1,[72][73][74] A powerful influence on resting and exercise hormonal response of a participant is the exercise training status: trained versus sedentary. Better-trained participants typically display greater effects on the neuroendocrine system response.…”