Abstract des Autors

The concentrations of plasma catecholamines at rest, the density of alpha-adrenoceptors on platelets and of betaadrenoceptors on lymphocytes as well as important postreceptor mechanisms have been determined after periods of endurance and high intensity training in highly trained swimmers (S) and long distance runners (R) in comparison to untrained subjects (UT). The sympathetic activity at rest was reduced after both training periods in S and R. However, the regulation of the adrenoceptor system seemed to be different: Training building up endurance led to a lower beta-receptor density (S=1100, R=1466 rec./cell) and -responsiveness compared with UT. High intensity training including anaerobic exercises resulted in an upregulation of the beta-receptor density at rest (S=2168, R=1989 rec./cell) and, therefore, in an increased responsiveness of betaadrenergic mechanisms. The NE/E ratio might be important for the regulation of the adrenoceptor system at rest. Verf.-Referat