Effects of Maximal Exercise on Nonspecific Immunity in Athletes under Trained and Detrained Conditions

Abstract

1755 Very few studies have examined the effect of maximal exercise on nonspecific immunity in athletes under trained and detrained conditions. PURPOSE: To investigate both the acute effects of maximal exercise and the chronic effects of training on nonspecific immunity in winter-sports athletes during different training periods. METHODS: In 15 winter-sports athletes, these acute and chronic effects were investigated during different training periods: (a) in summer, when the athletes were enhancing their aerobic capacity through extensive endurance training; (b) during the winter sports season, in early winter, when both endurance and athletic training were being undertaken; and (c) in spring, when the athletes were resting (detraining for a month). RESULTS: The mean value ± standard deviation) of the maximal oxygen uptake in each of the three training periods (a, b and c) were 65.4 ± 4.6 mL·kg−1·min−1, 63.1 ± 5.5 mL·kg−1·min−1, and 58.3 ± 5.8 mL·kg−1·min−1, respectively. Following maximal exercise, acute peripheral leukocytosis due to lymphocytosis and neutrophila was observed in all three periods. The capacity of isolated and stimulated neutrophils to produce reactive oxygen species as measured by luminol-dependent chemiluminescence (LDCL) was significantly enhanced after maximal exercise before and during the athletic season, but decreased during after-season detraining, suggesting that the conditioning state affected the exercise-induced changes in neutrophil functional status. Serum opsonic activity also showed a similar pattern. As for the chronic effects of training, a significant decline was particularly seen in the resting values of the segmented neutrophil count, the neutrophil LDCL response and the serum IgG level, in the pre-season training period. CONCLUSION: The nonspecific immune status of the subjects might have been partially compromised due to chronic overload while engaged in exhaustive endurance training under heat exposure.