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% V̇O2max. 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 post-exercise
recovery period were decreased activity of the pituitary-adrenocortical system and
delayed normalization of aldosterone level.
Key words
Dynamics of hormone responses - exercise - hormone - intra-individual variability
- threshold duration of exercise - training
