Effect of Ipratropium Bromide on EILO

Inclusion Criteria: * Patients must be diagnosed with EILO confirmed by Continuous Laryngoscopy During Exercise * Patients must be able to complete exercise testing * Patients must report dyspnea * Patients must have given assent with parental consent, understand all study procedures, and comply with them for the entire length of the study. Exclusion Criteria: * Patients that do not have EILO. * Patients who did not undergo diagnostic CPET with CLE. * Patients with hypersensitivity to atropine or its derivatives due to structural similarity with ipratropium bromide. * Patients with a history of atrial flutter and/or fibrillation * Patients taking anticholinergic medications that cannot be paused for 24 hours. * Unable to perform exercise tests * Current drug or alcohol use or dependence that, in the opinion of the site investigator, would interfere with adherence to study requirements. * Inability or unwillingness of patient or parent/legally authorized representative to give written informed consent.