Pro- and anti-inflammatory cytokine balance in strenuous exercise in humans

1. The present study investigates to what extent and by which time course p rolonged strenuous exercise influences the plasma concentration of pro-infl ammatory and inflammation responsive cytokines as well as cytokine inhibito rs and anti-inflammatory cytokines. 2. Ten male subjects (median age 27.5 years, range 24-37) completed the? Co penhagen Marathon 1997 (median running time 3:26 (h:min), range 2:40-4:20). Blood samples were obtained before, immediately after and then every 30 mi n in a 4 h post-exercise recovery period. 3. The plasma concentrations of tumour necrosis factor (TNF)alpha, interleu kin (IL)-1 beta, IL-6, IL-1ra, sTNF-r1, sTNF-r2 and IL-10 mere measured by enzyme-linked immunosorbent assay (ELISA). The highest concentration of IL- 6 was found immediately after the race, whereas IL-1ra peaked Ih post exerc ise (128-fold and 39-fold increase, respectively, as compared with the pre- exercise values). The plasma level of IL-1 beta, TNF alpha, sTNF-r1 and sTN P-r2 peaked in the first hour after the exercise (2.1-, 2.3-, 2.7- and 1.6- fold, respectively). The plasma level of IL-10 showed a 27-fold increase im mediately post exercise. 4. In conclusion, strenuous exercise induces an increase in the pro-inflamm atory cytokines TNF alpha and IL-1 beta and a dramatic increase in the infl ammation responsive cytokine IL-B. This is balanced by the release of cytok ine inhibitors (IL-1ra, sTNF-r1 and sTNF-r2) and the anti-inflammatory cyto kine IL-10. The study suggests that cytokine inhibitors and antiinflammator y cytokines restrict time magnitude and duration of the inflammatory respon se to exercise.