EFFECTS OF AN INTENSIVE 12-WK TRAINING-PROGRAM BY ELITE SWIMMERS ON NEUTROPHIL OXIDATIVE ACTIVITY

The effects of an intensive 12-wk training program by 12 national-leve l swimmers on neutrophil oxidative activity were studied. Eleven seden tary (untrained) subjects (6 males and 5 females) served as environmen tal controls. Blood samples (10 ml) were taken at rest from an antecub ital vein and neutrophils isolated by standard separation techniques. The oxidative burst activity of isolated neutrophils was assessed with an in vitro flow cytometric assay that used the fluorescent probe dih ydrorhodamine 123. Two-way ANOVA (repeated measures) showed that oxida tive activity was lower (P < 0.05) in the elite swimmers compared with the sedentary control group across the 12-wk period. Analysis of cell s from swimmers in training was made: repeated measures ANOVA provided evidence of a significant decline (P < 0.05) in the number of cells r esponding positively to in vitro challenge. Despite this decline, ther e was no significant difference in self-reported upper respiratory tra ct infection rate between the swimmers and sedentary individuals. Thes e data show that: (i) elite swimmers undertaking intensive training ha ve a significantly lower neutrophil oxidative activity at rest than do age- and sex-matched sedentary individuals; (ii) aspects of oxidative activity in swimmers are further suppressed during periods of strenuo us training, and (iii) the extent of the suppression does not appear t o be of clinical significance.