LYMPHOCYTES AND NK CELL-ACTIVITY DURING REPEATED BOUTS OF MAXIMAL EXERCISE

Effects on the immune system of 6-min ''all-out'' ergometer rowing wer e investigated over 2 days (2 x 3 bouts) in eight male oarsmen with a maximal oxygen uptake of 5.5 +/- 0.1. l/min (mean +/- SE). Blood sampl es mere obtained before, during, and 2 h after each bout and on the da y after the last bout. Compared with levels at rest, the first bout of exercise increased the concentration of leukocytes (2-fold); neutroph ilic granulocytes (2-fold); lymphocytes (2-fold); monocytes (a-fold); the blood mononuclear cell (BMNC) subsets CD3(+) (2-fold), CD4(+) (2-f old), CD8(+) (3-fold), CD16(+) (8-fold), CD19(+) (2-fold), and CD14(+) (2-fold); the NK cell activity (2-fold); and plasma interleukin-6 (3- fold) (P < 0.05). During the last bout even higher levels were noted f or leukocytes (3-fold); neutrophilic granulocytes (3-fold); lymphocyte s (4-fold); the BMNC subsets CD4(+) (3-fold), CD8(+) (5-fold), CD16(+) (13-fold), CD19(+) (5-fold), and CD14(+) (3-fold); and for the NK cel l activity (4-fold) (P < 0.05). During the recovery periods all values were at or above the level at rest, and elevated concentrations of le ukocytes (38%), neutrophilic granulocytes (48%), and lymphocytes (46%) reflected in the BMNC subsets and increased NK cell activity (119%) w ere also noted on the day after the last bout (P < 0.05). The results show that maximal exercise with large muscle groups provokes higher im mune responses during repetitive bouts.