Influence of fitness on the integrated neuroendocrine response to aerobic exercise until exhaustion.
A group of trained and sedentary men performed an incremental graded exercise-test to exhaustion in order to assess the organic response of the two main stress-activated systems: the sympathetic nervous system with its endocrine component (the adrenal medulla), and the hypothalamic-pituitary-adrenal (HPA) axis. Maximal plasma concentrations of ACTH, cortisol and endogenous opioids (beta-endorphins) were obtained at the end of the exercise-test in the trained group. Thus ACTH increased from basal value of 21.25 +/- 2.5 pg/ml to 88.78 +/- 11.8 pg/ml at the end of the exercise (p<0.01); cortisol, from 16.56 microg/dl +/- 4.94 microg/dl to 23.80 +/- 4.57 microg/dl in min 15 of the recovery period (p<0.001); and beta-endorphin from 21.80 +/- 8.33 pmol/ml to 64.36 +/- 9.8 pmol/ml in min 3 of the recovery period (p<0.05). Catecholamine levels were increased from initial values at the end of the effort test in both control and trained groups. Control subjects exhibited a higher responsiveness compared to trained and showed superior intrinsic stimulation of the sympathetic nervous system. These results reveal a different response according to fitness in a physical stress situation.
de Diego Acosta
A M
AM
Escuela de Medicina de la Educación Física y el Deporte, Universidad de Málaga, Spain. amda@uma.es
García
J C
JC
Fernández-Pastor
V J
VJ
Perán
S
S
Ruiz
M
M
Guirado
F
F
D000313:Adrenal Medulla / Q000378:metabolism*; D000324:Adrenocorticotropic Hormone / Q000097:blood; D000328:Adult; D002395:Catecholamines / Q000097:blood; D015444:Exercise / Q000502:physiology*; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D007030:Hypothalamo-Hypophyseal System / Q000378:metabolism*; D008297:Male; D010101:Oxygen Consumption; D010807:Physical Endurance; D010809:Physical Fitness; D010913:Pituitary-Adrenal System / Q000378:metabolism*; D001615:beta-Endorphin / Q000097:blood
D002395:Catecholamines; D001615:beta-Endorphin; D000324:Adrenocorticotropic Hormone; D006854:Hydrocortisone