PMN CELL COUNTS AND PHAGOCYTIC-ACTIVITY OF HIGHLY TRAINED ATHLETES DEPEND ON TRAINING PERIOD

We tested the hypothesis that polymorphonuclear leukocyte (PMN) cell c ounts and phagocytic activity determined by latex ingestion and supero xide anion production are influenced by different training periods. We investigated long distance runners before and up to 24 h after a grad ed exercise test to exhaustion during moderate training (MT) and inten se training (IT) and compared them with untrained (control) subjects. Cell counts and phagocytic activity at rest and after exercise did not differ significantly between MT and control. On the contrary, IT show ed a significant (P less than or equal to 0.05) decrease in PMN cell c ount at rest (2.55 +/- 0.3 cells/nl) compared with MT (3.63 +/- 0.2 ce lls/nl) and control (3.41 +/- 0.8 cells/nl). Furthermore, phagocytic a ctivity was significantly reduced (P less than or equal to 0.05) in IT at rest and after exercise compared with MT and control. A strong inv erse correlation (r = -0.75; P less than or equal to 0.01) between epi nephrine and superoxide anion production was found. These results prov ide evidence that the phagocytic activity depends on the training peri od and indicate impaired PMN functions during IT, which might lead to increased susceptibility to infection.