Effect of resistance training on inflammatory markers of older adults: A meta-analysis

Introduction: Low-grade inflammation is associated with several deleterious health outcomes and may aggravate sarcopenia and dynapenia during aging. A strategy to alleviate these conditions is resistance training (RT). Thus, the aim was to critically examine the effects of regular RT on inflammatory markers of older adults from previous studies.

Methods: The search was conducted on MEDLINE, July 2017. Only randomized controlled trials (RCTs) testing RT effects on C-reactive protein (CRP), tumor necrosis factor-α (TNF-α) and/or interleukin-6 (IL-6) of adults over 50 years-of-age were selected by two independent reviewers.

Results: The main meta-analyses showed RT reduced CRP in older adults (standard mean difference [SMD] = -0.61, 95%CI = -0.83; -0.31, p < 0.001), tended to reduce IL-6 (SMD = -0.19, 95%CI = -0.42; 0.02, p = 0.07) and did not change TNF-α. Further exploratory sub-group analyses showed a potential association of muscle mass for both CRP and TNF-α changes. Reductions in CRP and TNF-α only occurred in RCTs performing a higher number of exercises (>8), higher weekly frequency (3 times/week) and longer durations than 12 weeks.

Conclusions: Anti-inflammatory effects of RT were significant only for CRP with a tendency for a decrease in IL-6 as well. The exploratory analyses suggested the reduction in inflammatory markers could be dependent on increases in muscle mass and higher volume of RT protocols. These potential mediators of RT anti-inflammatory effects should be addressed in future meta-analyses to clarify the effects of RT on inflammatory markers of older adults with very specific conditions and larger numbers of studies.