Airway responsiveness and inflammation in adolescent elite swimmers

Abstract

Background Whereas increased airway hyperresponsiveness (AHR) and airway inflammation are well documented in adult elite athletes, it remains uncertain whether the same airway changes are present in adolescents involved in elite sport. Objective To investigate airway responsiveness and airway inflammation in adolescent elite swimmers. Methods We performed a cross-sectional study on adolescent elite swimmers (n = 33) and 2 control groups: unselected adolescents (n = 35) and adolescents with asthma (n = 32). The following tests were performed: questionnaire, exhaled nitric oxide (FeNO), spirometry, induced sputum, methacholine challenge, eucapnic voluntary hyperpnea (EVH) test, and exhaled breath condensate pH. Results There were no differences in FeNO, exhaled breath condensate pH, cellular composition in sputum, or prevalence of AHR to either EVH or methacholine among the 3 groups. When looking at airway responsiveness as a continuous variable, the swimmers were more responsive to EVH than unselected subjects, but less responsive to methacholine compared with subjects with asthma. We found no differences in the prevalence of respiratory symptoms between the swimmers and the unselected adolescents. There was no difference in FeNO, cellular composition of sputum, airway reactivity, or prevalence of having AHR to methacholine and/or EVH between swimmers with and without respiratory symptoms. Conclusion Adolescent elite swimmers do not have significant signs of airway damage after only a few years of intense training and competition. This leads us to believe that elite swimmers do not have particularly susceptible airways when they take up competitive swimming when young, but that they develop respiratory symptoms, airway inflammation, and AHR during their swimming careers.