Effect of training status on the sympathoadrenal activity during a supramaximal exercise in human

Background. The study investigated the concentrations of plasma catecholami ne, adrenaline (A) and noradrenaline (NA), and the adrenal medulla responsi veness to the sympathetic nervous activity in sprinters (S), endurance runn ers (E) and untrained subjects (U) during a supramaximal exercise (the Wing ate-test). Methods. A group of 19 men took part in the tests: 6 S (20.5 +/-0.7 years), 6 E (21.0 +/-1.0 years) and 7 U (20.9 +/-0.4 years). The maximal power (Wm ax) and the mean power (W) were determined from the Wingate-test on a cycle ergometer. The plasma lactate, A and NA were analysed at rest (La-0, A(0) and NA(0)), immediately at the end of the exercise (A(max) and NA(max)) and after 5 min recovery (La-max, A(5) and NA(5)). The disappearance of A and NA was judged by the difference between the maximal values and those determ ined after 5 min recovery (A(max)-A(5) and NA(max)-NA(5)) and the ratio A/N A was considered as an index of the adrenal medulla responsiveness to the s ympathetic nervous activity. Results. During the Wingate-test S exhibited higher performances and higher La-max than the two other groups. At the end of the Wingate-test the NA(ma x) values were similar in the three, groups whereas the A(max) values were significantly higher in S than in E and U (8.00 +/-0.5 nmol.l(-1) in S vs 3 .47 +/-0.30 nmol.l(-1) and 3.29 +/-1.14 nmol.l(-1) respectively in E and U) . This leads to a higher A(max)/NA(max) ratio for S compared to the other t wo groups (0.77 +/-0.10 in S vs 0.23 +/-0.03 and 0.28 +/-0.05, respectively in E and U). As the disappearance of A (Amax-A5) was significantly higher in S (6.80 +/-0.47 nmol.l(-1) in S vs 2.64 +/-0.19 nmol.l(-1) and 1.64 +/-1 .37 nmol.l(-1), respectively in E and U), the higher values of A(max) in S could be explained by an increase of the adrenal medullary secretory capaci ty in this group. Conclusions. It was concluded that essentially short term and intense exerc ises as sprint ones or interval-training may alter the adrenal medulla resp onsiveness to supramaximal exercise but not long duration exercises.