Airway remodeling and inflammation in competitive swimmers training in indoor chlorinated swimming pools

J Allergy Clin Immunol. 2012 Feb;129(2):351-8, 358.e1. doi: 10.1016/j.jaci.2011.11.010. Epub 2011 Dec 22.


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 unclear.

Objective: This study aimed to evaluate airway inflammation and remodeling in elite swimmers.

Methods: Twenty-three elite swimmers were tested during off-training 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 age-matched mild-asthmatic and 10 healthy nonallergic subjects were used for comparison.

Results: 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 changes.

Conclusion: Intense, long-term 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 long-term physiological and clinical consequences of these changes remain to be clarified.

Publication types

  • Controlled Clinical Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Airway Remodeling* / immunology
  • Allergens / immunology
  • Asthma / immunology
  • Asthma / pathology*
  • Asthma / physiopathology
  • Bronchi / immunology
  • Bronchi / metabolism
  • Bronchi / pathology
  • Bronchial Provocation Tests
  • Bronchoconstrictor Agents
  • Cell Count
  • Chlorine / adverse effects*
  • Eosinophils / immunology
  • Female
  • Humans
  • Inflammation / immunology
  • Inflammation / pathology*
  • Inflammation / physiopathology
  • Male
  • Mast Cells / immunology
  • Methacholine Chloride
  • Mucins / metabolism
  • Neutrophils / immunology
  • Nitric Oxide / metabolism
  • Skin Tests
  • Spirometry
  • Swimming Pools
  • Swimming*
  • T-Lymphocytes / immunology
  • Young Adult


  • Allergens
  • Bronchoconstrictor Agents
  • Mucins
  • Methacholine Chloride
  • Nitric Oxide
  • Chlorine