Exercise-induced bronchoconstriction and airway inflammation in elite long distance runners

Background: Exercise-induced bronchoconstriction (EIB) is highly prevalent in elite athletes and its pathogenesis involves airway inflammation, which has been well described in swimmers and winter endurance athletes; however, the prevalence of EIB and inflammatory profile of elite runners remains unknown. Objective: The aim of this study was to assess the prevalence of EIB and bronchial hyperresponsiveness (BHR) in elite long distance runners and to investigate airway inflammation. Methods: This cross sectional study enrolled 40 male non-asthmatic elite long distance runners (31.2±5.4 years; VO2=66.6±3.1 mL/Kg/min). All athletes underwent eucapnic voluntary hyperventilation test (EVH) to be diagnosed with EIB and were submmited to the following measurements: i) bronchial hyperresponiveness (methacoline provocation test), ii) airway inflammation (induced sputum and exhaled nitric oxide, FENO) and iii) maximal aerobic capacity (cardiopulmonary exercise testing). Informations about experience and volume of training were also obtained. Student t-test was used to compare EIB+ and EIB- athletes and the significance level was set at 5%. Results: The prevalence of EIB was 27.5% (11/40 athletes) and BHR was observed in 7.5% (3/40 athletes). Comparison between EIB+ and EIB- athletes showed that there was no difference neither in aerobic capacity nor in experience and volume of training; however, EIB+ athletes presented higher percentage of sputum eosinophils (p<0.001) and levels of FENO (p<0.001) compared to EIB- athletes. Conclusion: Our study demonstrated that elite long distance runners without asthma have eosinophilic airway inflammation and high prevalence of EIB and levels of FENO.