The effects of aerobic exercise training on inflammatory markers in adult tobacco smokers: A systematic review and meta-analysis of randomized controlled trials

Introduction

Aerobic exercise training may reduce systemic inflammation, but the effects of this on systemic inflammatory markers in adult tobacco smokers has not been systematically reviewed. Therefore, we evaluated the effects of aerobic exercise training on C-reactive protein (CRP) and tumor necrosis factor-α (TNF-α) in adult tobacco smokers using a systematic review and meta-analysis of randomized controlled trials.

Methods

A comprehensive literature search was carried out using PubMed/Medline, Web of Science, EMBASE, Google Scholar, and hand search of bibliographies of the retrieved English or Persian articles up to August 2023. This review only included randomized controlled trials which investigated the effect of aerobic exercise training on CRP and TNF-α in adult smokers, based on a predefined inclusion and exclusion criteria.

Results

A total of 1641 articles were identified. Six studies were included in the review and four evaluated CRP and two evaluated TNF-α in only males. The meta-analysis demonstrated that aerobic exercise training significantly decreased TNF-α concentrations in males (MD = −6.68, 95 % CI = −13.90 to −0.54, P = 0.05). CRP concentrations did not decrease significantly when the data from the four studies were pooled (MD = −0.17, 95 % CI = −0.37 to 0.03, P = 0.09).

Conclusion

Aerobic exercise training may reduce the concentration of TNF-α in male smokers, but it does not have a significant effect on CRP concentrations. However, these findings are based upon a small number of studies, that enrolled either exclusively male or female participants, and further investigation is necessary to increase statistical inference.