Exercise as a treatment for inflammation [1]

Regular physical activity is reported to decrease markers of inflammation, although the correlation is imperfect and seems to reveal differing results contingent upon training intensity. For instance, while baseline measurements of circulating inflammatory markers do not seem to differ greatly between healthy trained and untrained adults, long-term training may help reduce chronic low-grade inflammation. On the other hand, levels of the anti-inflammatory cytokine IL-6 (interleukin 6) remained elevated longer into the recovery period following an acute bout of exercise in patients with inflammatory diseases, relative to the recovery of healthy controls. It may well be that low-intensity training can reduce resting pro-inflammatory markers (CRP, IL-6), while moderate-intensity training has milder and less-established anti-inflammatory benefits. There is a strong relationship between exhaustive exercise and chronic low-grade inflammation. Marathon running may enhance IL-6 levels as much as 100 times over normal and increases total leuckocyte count and neturophil mobilization.

Regarding the above, IL-6 had previously been classified as a pro-inflam- matory cytokine. Therefore, it was first thought that the exercise-induced IL-6 response was related to muscle damage. However, it has become evident that eccentric exercise is not associated with a larger increase in plasma IL-6 than exercise involving concentric “nondamaging” muscle contractions. This finding clearly demonstrates that muscle damage is not required to provoke an increase in plasma IL-6 during exercise. As a matter of fact, eccentric exercise may result in a delayed peak and a much slower decrease of plasma IL-6 during recovery.