Two observational studies examined the acute effect of a single-session exercise on inflammatory cytokine (e.g., IL-6) in patients with RA; one of the studies found no significant change in IL-6 (86), whereas the other observed IL-6 level sharply increased in the first one hour, then gradually decreased, and returned to pre-exercise level in 24 hours (87). This evidence concerns the gene IL6 and rheumatoid arthritis.