This study aims to address potential effects from Atrovent in patients with E-ILO verified during a continuous laryngoscopy exercise (CLE) test. The study will primarily include 20 patients consecutively referred to our clinic for EIIS and diagnosed with E-ILO during a routine CLE test. Requirement for inclusion will be a CLE score ≥ 3. The primary endpoint will be the laryngeal response to maximal exercise, described quantitatively by a blinded observer using the CLE score system. Two CLE tests will be performed in each subject, one with - and one without - prior treatment with Atrovent. The patient will thus serve as her/his own control. Half the patients will receive Atrovent before the first study test (at T1), the other half before the second (at T2).