Patients With Chronic Obstructive Pulmonary Disease at Altitude - Effect of Nocturnal Oxygen on Breathing and Sleep

The purpose of this study is to investigate the effect of nocturnal oxygen therapy during a stay at moderate altitude on breathing and sleep of patients with chronic obstructive lung disease.

Patients with moderate to severe chronic obstructive pulmonary disease living below 800 m will be invited to participate in a randomized, cross-over field trial evaluating the hypothesis that nocturnal breathing and sleep during nights spent at moderate altitude are improved by oxygen therapy via a nasal cannula compared to room air (sham oxygen). Outcomes will be assessed at low altitude (Zurich, 490 m, baseline), and during 2 study periods of 2 nights each spent at moderate altitude (St. Moritz Salastrains, 2048 m) separated by a wash-out period of at least 2 weeks spent at low altitude (\<800 m).