SHORT-TERM CHANGES IN THE IMMUNE-SYSTEM OF ELITE SWIMMERS UNDER COMPETITION CONDITIONS - DIFFERENT IMMUNOMODULATION INDUCED BY VARIOUS TYPES OF SPORT

This study was designed to investigate changes in the immune system of elite swimmers compared with well-conditioned age- and sex-matched co ntrols in relation to a competition swim (field study). Furthermore, t he aim was to reveal possible differences in immune system changes dep ending on the type of sport performed by comparing with an earlier stu dy of similar design, from the same laboratory that tested elite runne rs in relation to a competition run. The swimmers were tested before, immediately after and 2 h and 24 h after a competition swim. Lymphocyt e subsets (CD5, CD3, HLA-DR, CD4, CD8, CD19, CD3/CD16+56, CD57, CD18, CD16/CD122) all increased after the run, decreased to normal or subnor mal levels after 2 h, and returned to normal after 24 h (absolute numb ers). The findings were identical for the swimmers and the age- and se x-matched control group. No change in polymorphonuclear granulocyte mi gration was found. The lymphocyte proliferative responses decreased 2 h after the exercise. No changes were seen in plasma cytokine levels ( interleukin-1 beta (IL-1 beta), interleukin-6 (IL-6), and tumor necros is factor or (TNF-alpha)) in relation to exercise, but significantly l ower baseline values for IL-6 were observed in the swimmers. An increa se in total natural killer cell activity immediately after exercise, f ollowed after 2 h by a decrease, was seen in both swimmers and control s. Finally, no complement activation was detected. Compared with an ea rlier study of elite runners, differences were seen in granulocyte che motactic response, TNF-alpha plasma activity and the lymphocyte prolif erative response to mitogen. These differences might be explained by t he degree of immune system activation following muscle damage during e xercise, inducing an increase in cytokines, which are known to activat e and modulate both lymphocytes and granulocyte function. Our findings demonstrate identical exercise-induced, immune system changes in elit e swimmers and well conditioned controls, and furthermore, the finding s suggest that different types of sport performed at maximum intensity induce different immune system changes.