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The International Olympic Committee Medical Commission (IOC-MC) requires athletes to provide the result of an objective test to support a diagnosis of asthma or exercise-induced bronchoconstriction (EIB) if they want to inhale a beta-2-agonist. The purpose of the study was to evaluate the airway response to a methacholine challenge and to hyperpnea induced by exercise in the field and in the laboratory or that induced voluntarily by eucapnic hyperpnea in a group of female elite swimmers.Sixteen female nonasthmatic elite swimmers performed a eucapnic voluntary hyperpnea (EVH) test, a field-based exercise test (FBT), a laboratory-based exercise test (LBT), and a methacholine challenge. The criteria suggested by the IOC-MC were used to define a positive response to the challenges (EVH, field test, and laboratory test: minimum 10% decrease in FEV1; methacholine: PD20or = 2 micromol).Eight swimmers (50%) had at least one positive test to hyperpnea. Five were identified with the EVH test, four with FBT, and four with LBT. None were identified using methacholine. Three swimmers with airway hyperresponsiveness to exercise would have been identified using a higher cutoff for methacholine (PD20or = 8 micromol).The EVH test is the test that diagnoses most swimmers with an abnormal response to hyperpnea, but not all cases of EIB are identified with the EVH test. Performing a methacholine test using IOC-MC's cutoff value does not improve the chances of diagnosing EIB. We recommend performing the EVH test when diagnosing and evaluating EIB in elite swimmers and if EVH test negative then proceeding to a strenuous LBT.

In 70-80% of asthmatic patients, an attack of asthma will follow 6-10 min of strenuous exercise. The increase in airway resistance is accompanied by hyperinflation and arterial hypoxemia and makes it difficult to continue or resume exercise. The past 10 yr have seen major advances in the prevention and treatment of exercise-induced asthma (EIA). The beta-sympathomimetic drugs, when administered as aerosols, have been shown to be most effective in reversing the airway obstruction, hyperinflation, and exercise-induced hypoxemia in patients with asthma. When administered as aerosols prior to exercise, the increase in airways resistance, hyperinflation, and hypoxemia are blocked in about 90% of patients. In addition to the sympathomimetic agents, sodium cromoglycate will also ameliorate or prevent EIA in 60-70% of patients. Oral administration of beta-sympathomimetics or methylxanthines is less efficacious in the prevention or treatment of EIA. Delay in absorption from the gastrointestinal tract requires at least 1-2 h before a significant response is observed. Prevention of EIA requires an adequate blood level, possibly because a high concentration of the drug does not reach the airway when the drug is given by the oral route. More importantly, aerosol administration prevents EIA at a fraction of the dose required orally. The side effects, such as nausea, tachycardia, and skeletal muscle tremor commonly observed following oral bronchodilator administration are rare with aerosol therapy.