The prevalence of airway hyperresponsiveness (AHR) is very high in elite swimmers, reaching 80% in certain studies. Repeated Chlorine-derivatives exposure may be a major causative factor for its development. Asthma diagnosis is generally made on the basis of clinical characteristics. The demonstration of a variable bronchial obstruction through positive expiratory flow reversibility to a bronchodilator, spontaneous variations of airway obstruction or a positive provocation test (methacholine, eucapnic voluntary hyperpnoea…) is necessary to avoid false diagnosis. Currently asthma treatment in swimmers is the same as in the general population. A short-acting bronchodilator is often prescribed to avoid occasional symptoms, combined with an inhaled corticosteroid or an antagonist of Leukotriene if asthma symptoms are persistent. Previous studies have shown a reduced efficiency for asthma medication in elite athletes compared with non-athletes. The specific response to different medications remains to be studied in athletes. The effects of a short-acting bronchodilator in swimmers with AHR, especially when asymptomatic, on pulmonary function and performance have not yet been studied. Moreover, the significance of a positive bronchial provocation test remains to be studied in asymptomatic swimmers with AHR.

Our hypothesis is that swimmers with a positive bronchial provocation challenge have not necessarily an exercise-induced bronchoconstriction during swimming and the use of a bronchodilator will be unnecessary. Chlorine-derivatives exposure may be responsible for a weakness of the epithelium layer but warm and humid atmosphere of the swimming-pools may be protective for the development of a bronchoconstriction. Thus we also hypothesis that during a field test outside the swimming pool, swimmers will develop an exercise-induced asthma, and will need to take a bronchodilator in prevention.

Inclusion Criteria:

• Swimmer (at least 10h/week) aged from at least 14 years.

Exclusion Criteria:

• Smoker, obese or other disease which may interfere with the study. Some parts of the study may exclude swimmers taking inhaled corticosteroids.