Previous results from endurance training in women have been discrepant in regard to
influences on basal and maximum adrenocorticotropin (ACTH) and β-endorphin (β-EP)
concentrations before and after exhaustive exercise. A group of 23 untrained young
women ran 3 times a week for 30 min at an individual specific intensity corresponding
to their respective anaerobic threshold, derived from the lactate performance curve
obtained from prior treadmill testing. ACTH and β-EP were measured at rest, as well
as 5 and 30 min after exhaustive progressive spiroergometric treadmill running, both
before and after the 8 week endurance training program. Basal b-EP did not change
after training, but less elevated concentrations were measured both 5 (p < 0.05) and
30 min (p < 0.05) after exercise, after the training program. In contrast, the resting
concentration of ACTH increased significantly; the respective maximum concentration
was less elevated after 5 min and much less elevated 30 min after the exercise (p
< 0.05). Positive correlations were found after the exhaustive exercise between β-EP
and ACTH, as well as between maximum lactate and ACTH. Training was associated with
significant changes in maximum running speed (p < 0.01), maximum oxygen uptake (p
< 0.01) and the running speed at the anaerobic threshold (p < 0.05). Maximum lactate
and the level of perceived exertion remained unchanged, showing a similar level of
exhaustion. Our results indicate that endurance training modulates the hormonal responses
of β-EP and ACTH to comparable workloads of high intensity. After the training program
the maximum concentrations are significantly lower during the recovery period. The
tendency to elevated basal ACTH, and thus elevated Cortisol, might be a new factor
to consider in evaluation of endurance training induced hormonal disturbances in women.
Key words
β-Endorphin - ACTH - endurance training - women
