Abstract des Autors

To study possible effects of pharmacological beta-blockade on the beta-endorphin response, 10 not specific trained male voluteers (age 25.7 +/- 2.9 years) performed an exhausting cycle ergometry with the work load of the individual anaerobic threshold after respective medication of placebo (P) or Metoprolol (M) for 3 weeks. To determine the concentrations of beta-endorphin (E); cortisol (C), adrenaline (A) and noradrenaline (N), venous blood samples were taken before, during, and after exercise. Test duration was 26% less under M (P 89/M 66 min). Maximum levels of E at the end of exercise were under M and P 2.5 times higher than at the beginning. The first increase of E was found under P between the 50th and 75th min, under M between the 25th and 50th min. Among the catecholamines A was significantly higher under M in the 50th min, but there was no correlation with the response of E. C showed significant increase under M and P at the end of exercise and a positive correlation with E during the first minutes of the recovery. Conclusion: beta-blockade has no substantial effect on the response of E during endurance exercise. Beta-adrenergic stimulation is of no special importance for the increase of E during physical exercise. Verf.-Referat