The Effect of Exercise Training on Inflammatory Markers in Patient with Metabolic Syndrome: A Systematic Review and Meta-analysis

Introduction: Metabolic syndrome is associated with an increase in chronic inflammation, in which exercise training may be an effective intervention for the improvement of inflammatory markers. Accordingly, this study aimed to investigate the effect of exercise training on the inflammatory markers of interleukin 6 (IL-6), tumor necrosis factor alpha (TNF-α), and C-reactive protein (CRP) in patients with metabolic syndrome. Materials and Methods: In this study, the PubMed, Scopus, and Web of Science databases were searched during June 2022 for studies addressing the effects of exercise training versus control on inflammatory factors, including IL-6, TNF-α, and CRP. The search keywords were exercise training, inflammation, and metabolic syndrome. Standardized mean difference (SMD) and 95% confidence interval were used to determine the effect size using CMA2. Results: Twenty-two studies including 779 subjects with metabolic syndrome were included in the meta-analysis. Exercise training significantly decreased TNF-α [-0.74 (CI: -0.24 to -1.24), p=0.003] and CRP [-0.56 (CI: -0.25 to 0.87, p=0.001); however, the effect of exercise training on the decrease of IL-6 was not significant [-0.32 (CI: 0.20 to -0.85), p=0.22]. Conclusion: Exercise training decreases inflammatory markers in patients with metabolic syndrome, which may be a reason for the positive effects of exercise training on improving the metabolic status and cardiovascular health in such patients.