Exercise-induced bronchoconstriction in marathon runners is associated with higher nasal neutrophilic infiltrate after marathon

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Exercise-induced bronchoconstriction (EIB) is a transient airway narrowing associated with physical activity, being more common among endurance athletes. Injury to the airway epithelium and greater airway eosinophilia have been found to be distinctive immunopathologic features of asthma with EIB, demonstrating an inflammatory basis of EIB A. In this context we aimed to investigate the association between EIB with airway inflammation in non-asthmatic marathon runners before and after a marathon race. There were recruited 39 volunteers and EIB was determined through spirometry test, before and after maximum effort. Groups were divided in EIB+ (n=9) and EIB- (n=28). The study of upper airway was by the count of neutrophils obtained by a nasal swab. Neutrophil % in nasal swab significantly increased after running in EIB+ subjects (p=0.036), whereas nasal swab in EIB- subjects showed decreased neutrophil counts after the race (p=0.007). The comparison between groups showed a difference in neutrophil percentage immediately after the marathon race (p=0.01). Lymphocyte percentage tended to decrease in EIB- subjects (p=0.052) but was stable in EIB+ subjects (p=0.7). In contrast, epithelial cells increased significantly in EIB- subjects (p<0.001) but remained stable in EIB+ subjects (p=0.527). The nasal neutrophil count, could also reflect neutrophil increase in the lower airways, as observed in elite athletes after intense exercise. In EIB- subjects, running a marathon increased nasal epithelial cell count, which could reflect epithelial shedding and suggesting that inflammation is an important mechanism linked to the pathogenesis of EIB without asthma.

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