Influence of different modes of exercise training on inflammatory markers in older adults with and without chronic diseases: A systematic review and meta-analysis

Ageing can be accompanied by increased inflammation, which contributes to the development of sarcopenia. Exercise training could be effective for preventing sarcopenia and mitigate inflammation and thus a viable intervention in ageing. Therefore, we performed a systematic review and meta-analysis to investigate the effects of exercise training on markers of inflammation including interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and C-reactive protein (CRP) in older adults (≥65 years). Exercise-based interventions are most successful in preventing the decline in skeletal muscle mass and in preserving or ameliorating functional capacities with increasing age. PubMed and Web of Science were searched through to December 2021 using "exercise", "inflammatory markers", "elderly", and "randomized controlled trial" to identify randomized trials evaluating the effects of exercise training versus control groups on IL-6, TNF-α, and CRP in older adults with mean ages ≥ 65 yrs. Standardized mean differences (SMD) and 95% confidence intervals (95% CIs) were determined using random effects models. Forty studies involving 49 trials and 1,898 older adults were included in the meta-analysis. Overall, exercise training reduced IL-6 [−0.17 (95% CI −0.32 to −0.02), p = 0.02], TNF-α [−0.30 (95% CI −0.46 to −0.13), p = 0.001], and CRP [−0.45 (95% CI −0.61 to −0.29), p = 0.001]. Subgroup analyses showed that IL-6 was reduced significantly by combined training, TNF-α by aerobic training, and CRP by aerobic, resistance, and combined training. In addition, exercise training reduced IL-6 and TNF-α in older adults with chronic diseases, and CRP in older adults with and without chronic diseases. The current results highlight that exercise training, regardless of exercise type, has small to moderate beneficial effects on markers of inflammation in older adults, particularly in those with chronic diseases.