Effect of exercise interventions on cytokines and myokines in human tobacco smokers A systematic review

Abstract

Tobacco smoking causes ongoing low-level inflammation, shown by higher levels of pro-inflammatory cytokines like CRP, IL-6, and TNF-alpha. Physical exercise can help reduce inflammation, but its effects in human smokers remain unclear. Objective: This review aimed to identify and assess studies published from 2000 to 2026 involving human smokers, using exercise as the primary intervention, and measuring at least one cytokine or myokine. Methods: We searched five databases following PRISMA 2020 guidelines. Studies had to include human smokers, use exercise as the main intervention, and measure at least one cytokine or myokine. Systematic reviews and meta-analyses were excluded. Eight studies met these criteria and were rated for quality using the PEDro scale. Results: The eight included studies (n = 346 smokers; 2006–2022; Australia, Iran, New Zealand) examined training programs (4–12 weeks) or single exercise sessions. They measured TNF-alpha, IL-6, CRP, IL-10, IL-1beta, IL-1ra, MCP-1, CC16, and SP-D. Aerobic training lowered TNF-alpha and IL-6 in male smokers, but CRP results varied by sex and smoking type. Acute exercise increased TNF-α and IL-6 more in smokers than in non-smokers. IL-10 increased after training. Aerobic training with vitamin D reduced lung-specific proteins (CC16, SP-D). Conclusion: Within a small, heterogeneous evidence base, aerobic training appears to lower pro-inflammatory cytokines, particularly TNF-alpha and IL-6, in male smokers. CRP results are mixed and seem to depend on sex and smoking type. Acute exercise may amplify cytokine responses, possibly reflecting tobacco-related immune changes. These findings are preliminary and more large studies are needed to confirm them.