1. Department of Respiratory Medicine, Oslo University Hospital, Rikshospitalet, Oslo, Norway;
2. Institute of Clinical Medicine, University of Oslo, Oslo, Norway;
3. Dept of Pediatric Oncology and Haematology, Oslo University Hospital, Rikshospitalet, Oslo, Norway;
4. Department of Cardiology, Oslo University Hospital, Rikshospitalet, Oslo, Norway;
5. The Norwegian School of Sport Sciences, Oslo, Norway;
6. Department of Pulmonary Medicine, Oslo University Hospital, Ullevål, Norway