Comparison of decreases in (A) HOMA-IR, and serum levels of (B) IL-1, (C) hs-CRP, (D) TNF-α and (E) IL-8 in different groups of patients with MS. The decrease in HOMA-IR score increased along with the increase in swimming time per session. No significant differences in HOMA-IR were detected among groups A-D, while the score significantly increased in group E compared with group A. Decreases in serum levels of IL-1, hs-CRP, TNF-α and IL-8 were significantly higher in groups B-E compared with group A. *P<0.05. HOMA-IR, homeostatic model assessment of β-cell function and insulin resistance; IL, interleukin; hs-CRP, high sensitivity C-reactive protein; TNF-α, tumor necrosis factor α; group A, metabolic syndrome with no swimming intervention; groups B-E, swimming intervention for 15, 30, 45 and 60 min per session, respectively.