1. National Institute for Health Research Oxford Biomedical Research Centre, University of Oxford, Oxford, United Kingdom
2. Oxford Centre for Respiratory Medicine, Oxford University Hospitals NHS Foundation Trust, Oxford, United Kingdom
3. Department of Pulmonology and Sleep Disorders Centre, University Hospital of Zurich, Zurich, Switzerland
4. Centre for Integrative Human Physiology, University of Zurich, Zurich, Switzerland; and
5. Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom