Corticotroph axis sensitivity after exercise: Comparison between elite athletes and sedentary subjects

Strenuous exercise activates the hypothalamic-pituitary-adrenal ( HPA) axis. Several reports showed that physical training is associated with a decreased efficiency of the feedback control of HPA axis. The aims of the present study were: 1) to evaluate the differences in the mechanical , hormonal , and lactate responses to a high-intensity isokinetic exercise among different groups of competitive athletes ( CA , no.=20) of power and endurance disciplines and sedentary controls ( SED , no.=10) ; 2) to determine the effects of the training status on the HPA axis responsiveness following exercise , as indirectly evaluated by the rates of ACTH , cortisol , and DHEA recovery after exercise. CA and SED fulfilled eight sets of twenty concentric contractions of the knee extensors at 180°/sec angular velocity throughout a constant range of motion ( 100°). There was a rest period of 30 sec between each set and a 3-min rest period between the two legs. Before , immediately after the isokinetic exercise and at different times in the subsequent 120 min of recovery , blood and saliva were sampled to determine plasma ACTH , salivary cortisol , serum DHEA , and serum lactate concentrations. CA showed a higher cortisol response to exercise than SED , whereas no differences were found in the responses of ACTH , DHEA and lactate. In the athlete group the exercise-induced increases of ACTH , cortisol , and lactate were higher in power athletes with respect to endurance athletes. No differences were observed between athletes and SED in the rates of hormonal recovery after exercise: this finding does not support the concept that a reduced feedback control of HPA axis can represent a feature of trained individuals.