EFFECTS OF A LONG-TERM TRAINING-PROGRAM OF INCREASING INTENSITY ON THE IMMUNE FUNCTION OF INDOOR OLYMPIC CYCLISTS

We have studied, on blood samples, the level of immunocompetence (conc entration of immune cells, phagocytic process of polymorphonuclear neu trophils, proliferative response of lymphocytes to mitogens), the asco rbic acid content of such immunocompetent cells and the ''stress hormo ne'' status (cortisol, ACTH and beta-endorphin) of 10 cyclists, member s of the Spanish Indoor Olympic Team and participants in the Olympic G ames of Barcelona '92. The study was performed twice during their trai ning for such an event: during the third year of the program (February , 1991) and immediately before the Games (June, 1992). As regards the phagocytic process of neutrophils, we studied the different steps of t his proces: adherence to endothelium, directed mobility or chemotaxis, ingestion of latex beads and superoxide anion production measured by the nitroblue tetrazolium (NBT) reduction test. We observed a statisti cally significant increase in chemotaxis and NBT redution activity jus t before the Games as compared to the third year of the program, where as variations were not found in the other parameters. The values of th e proliferative capacity of lymphocytes were slightly higher in June ' 92 than in February '91, but no statistically significant differences were found. The ascorbic acid content decreased strikingly (especially in lymphocytes) immediately before the Games. Regarding the stress ho rmones and neuropeptides (cortisol, ACTH and beta-endorphin), we obser ved an increase in serum ACTH and beta-endorphin levels in the last de termination (June '92) in comparison to the first one (February '91). These results suggest that, at the end of a long-term training program , no immunosuppression occurs, although an important increase in the c oncentration of stress hormones (ACTH and beta-endorphin) is found. Th is is probably caused by the psychological stress associated to the pa rtiipation in such an important event as the Olympic Games.