Pre-flight Evaluation of Adult Patients With Cystic Fibrosis

The purpose of the study is to investigate the relationship between hypoxemia achieved during Hypoxia Altitude Simulation test and sea level values of pulmonary function, arterial blood gases, pulse oximetry and cardiopulmonary exercise test variables. In addition, to study the effect of slow walk in a hypoxic environment, comparable to slow walking along the aisle.