Abstract des Autors

We studied 15 young, well trained athletes (age 12-14 years) by Montoye Step-Test (MST). The electrocardiogram (ECG) was monitored by an ergometric computerized system plotting by averaging the heart rate-time curve. The velocity of heart rate recovery during the first minute after MST was determined by monoexponential fitting. Plasmatic levels of beta-endorphin were measured by RIA at rest, at the first recovery minute and 30 min later. Plasmatic levels of BEP immediately after MST were significantly higher than basal (12.14+/-3.09 vs 3.37+/-1.57 pg/ml; p<0.009) whereas BEP values at 30 minutes were close to those in basal conditions (5.41+/-2.08 pg/ml). BEP release was closely related to the velocity of decrease of heart rate in the first recovery minute by simple linear regression analysis (Y = -324.145 +121.402 x, p<0.0005). Our data suggest that the release of BEP after MST is related to the fall of adrenergic tone and to rebound hypervagotonia considering the inhibitory effect of the endogenous opioid peptides on sympathetic discharge. Further investigations are needed however to support this research hypothesis. Verf.-Referat