[Conjugated plasma catecholamines are lower in power athletes at rest and in physical work than in untrained...

Lower levels of free plasma catecholamines, noradrenaline and adrenaline were recently described in statically trained athletes under identical work loads during incremental cycling as compared with untrained control subjects. These differences point to a control of sympathetic activity by static training. Theme of the presented investigation is the question of additional training-dependent alterations of the conjugated plasma catecholamines in statically trained athletes. Eight competition weight lifters (21 +/- 2 years of age; 73 +/- 10 kg body weight) and seven untrained healthy control subjects (26 +/- 6 years; 75 +/- 4 kg) were investigated. The conjugated catecholamines were radioenzymatically determined as the difference between total and free catecholamines. The investigated subjects performed an incremental, exhaustive bicycle ergometric test in an upright body position. Before exercise, the levels of conjugated plasma dopamine (P less than 0.10), of conjugated noradrenaline (P less than 0.001) and conjugated adrenaline (P less than 0.10) are 2-3 times lower in statically trained athletes than those of the control subjects. The conjugated catecholamines did not show any significant changes during exercise, the significant differences between both groups (P less than 0.05-P less than 0.01) were therefore also observed during exercise. In contrast to the free plasma catecholamine responses, the conjugated catecholamine fractions are seen as indicators of long term alterations of the sympathetic activity.