Hyperventilation Versus Exercise Testing Sensitivity in Exercise Induced Asthma

The diagnosis of exercise-induced bronchospasm (EIB) is difficult. The metacholine challenge test is not enough specific for the diagnosis of EIB. The exercise challenge test on a cycle ergometer is often use to diagnose this condition. This test has very high specificity, but not enough sensibility because the ventilation achieved during this test is often not big enough to induce a bronchospasm, especially in trained athletes. Eucapnic voluntary hyperventilation (EVH) is the recommended test of the Olympic National committee to establish the diagnosis of EIB, but there are no study comparing the sensibility and specificity of the cycle ergometer challenge test and the isocapnic hyperventilation in an establish population of asthmatics. The investigators assume that the sensitivity and specificity of EVH are higher than those of the cycle ergometer for the diagnosis of EIB in a population of asthmatics with symptoms suggestive of bronchospasm on exertion. In a population of asthmatics with exercise symptoms, what is the sensitivity and specificity of EVH and exercise challenge on a cycle ergometer for the diagnosis of EIB?