Anti-Inflammatory Effects of Exercise on Metabolic Syndrome Patients: A Systematic Review and Meta-Analysis

BACKGROUND: Increments in inflammatory indicators and low levels of physical activity are correlated to the expansion of the metabolic syndrome (MetS). OBJECTIVE: The purpose of this study was to establish if exercise training ameliorates inflammatory status in MetS patients. DATA SOURCES: PubMed, CINAHL, and Medline, Google Scholar, and Scopus databases and reference lists of included studies were searched. STUDY SELECTION: Twenty randomized controlled trials (RCTs) of exercise-training impact on inflammatory markers (tumor necrosis factor (TNF) α, C-reactive protein (CRP), interleukin (IL) 6, IL-8, IL-10, and IL-18) with concurrent control groups were included in this analysis. RESULTS: Results demonstrated an overall significant decrease in serum levels of TNF-α (mean difference (MD): -1.21 pg/ml; 95% confidence interval (CI): -1.77, -0.66), CRP (MD: -0.52 mg/l; 95% CI: -0.79, -0.25), IL-8 (MD: -1.31 pg/ml; 95% CI: -2.57, -0.06), and a significant increase in IL-10 (MD: 0.48 pg/ml; 95% CI: 0.10, 0.86). But exercise training did not change the level of IL-6 (MD: -0.69 pg/ml; 95% CI: -1.53, 0.14) and IL-18 (MD: -53.01 pg/ml; 95% CI: -166.64, 60.62). CONCLUSION: Exercise training improves TNF-α, CRP, IL-8, and IL-10 levels in patients with MetS. For some variables, isolated aerobic exercise, and combined aerobic and resistance exercise appears to be optimal. Future research is needed to clarify the mechanisms underlying exercise training's effect on this population's inflammatory markers. More studies are required to confirm these findings.