[Performance modification in sports by beta receptor blockers]

Abstract

Beta-adrenoceptor-blockers modify the physical performance due to their haemodynamic and metabolic effects. Additionally, these substances influence the concentration of serum-potassium and the thermoregulation. The reduction in heart rate yields to a diminished cardiac output resulting in a restricted muscular blood flow at submaximal and maximal exercise. After beta-blockade, O2-uptake at submaximal work load as well as maximal aerobic capacity is slightly reduced. Lipolysis is restricted by acute beta-blockade, but this effect can be compensated for by enhancement of catecholamine-independent lipolysis during chronic treatment with beta-adrenoceptor blockers. At submaximal loads, glycogenolysis is not influenced; at maximal exercise, glycogenolysis is reduced by non-selective beta-blockers but not by beta 1-specific ones. Arterial peak lactate concentration usually is diminished. After beta-adrenoceptor-blockade, the concentration of serum-potassium increases slightly, and sweat production is enhanced. Beta-adrenoceptor-blockers influence the performance in different sports to a various extent, due to the multitude of the different effects they take.