[Free and conjugated plasma catecholamines, lactate behavior and oxygen uptake at rest and in staged physical exertion as well as alpha receptor density in intact thrombocytes in trained athletes].

The influence of chronic static training on free and conjugated plasma catecholamines was investigated in 8 statically trained athletes (21 +/- 2 years of age) at rest and during incremental ergometric cycling. Plasma catecholamines are seen as biochemical indicators of the over-all sympathetic activity. Alpha-2-adrenoreceptors were additionally determined as one parameter of the organism's sensitivity to catecholamines. During modest and heavy exercise, free plasma noradrenaline and adrenaline are comparably low in statically and endurance trained athletes. They are lower than in untrained subjects. During exhaustion, however, free adrenaline responses of the statically trained athletes only amount to 30-50% of the concentrations observed in endurance trained athletes and untrained subjects. Free plasma dopamine and conjugated plasma catecholamines do not show any significant changes during ergometric exercise. Free and conjugated catecholamines correlate positively. Positive correlations are also observed between blood pressure and plasma catecholamines. These correlations however are clearer between conjugated catecholamines and blood pressure. This is also recognizable for the negative correlation between alpha-2-receptor density on intact platelets (1078 +/- 323 binding sites per cell) and conjugated catecholamines. In conclusion, statically trained athletes also show an alteration of sympathetic tone (catecholamines) comparable to that observed in endurance trained athletes. Maximal adrenaline responses however are lower in statically trained athletes than in endurance trained or untrained subjects. The alpha-adrenoreceptor density on intact thrombocytes seems to be increased in statically trained athletes.