airway remodeling and inflammation in competitive swimmers training in indoor chlorinated swimming pools background airway disorders are common in regular chlorinated swimming pool attendees particularly competitive athletes but the impact of intense swimming training on airway function and structure remains unclearobjective this study aimed to evaluate airway inflammation and remodeling in elite swimmersmethods twentythree elite swimmers were tested during offtraining season all had exhaled nitric oxide measurement methacholine test eucapnic voluntary hyperpnea challenge allergy skin prick tests and bronchoscopy with bronchial biopsies clinical data and tissues from 10 agematched mildasthmatic and 10 healthy nonallergic subjects were used for comparisonresults swimmers had increased airway mucosa eosinophil and mast cell counts than did controls p 05 they had more goblet cell hyperplasia and higher mucin expression than did healthy or asthmatic subjects p 05 a greater submucosal type i and iii collagen expression and tenascin deposition was also observed in swimmers than in controls p 05 neither exhaled nitric oxide nor airway responsiveness to methacholine or eucapnic voluntary hyperpnea challenge correlated with these inflammatory and remodeling changesconclusion intense longterm swimming training in indoor chlorinated swimming pools is associated with airway changes similar to those seen in mild asthma but with higher mucin expression these changes were independent from airway hyperresponsiveness the longterm physiological and clinical consequences of these changes remain to be clarified