Effects of physical activity in polluted air on physiological health in healthy populations: A systematic review and meta-analysis of controlled trials

= 74%, k = 5, very low CoE) decreased, whereas results for inflammatory cytokines were inconsistent. Findings for hematological and inflammatory markers should be interpreted cautiously given heterogeneity and generally low certainty of evidence. Overall, these modest but consistent changes suggest that repeated exposure during exercise may accumulate respiratory and cardiovascular risks, underscoring the need to promote activity in cleaner environments to safeguard health benefits.