1. Medical Department B, Section of Aviation Medicine, Copenhagen University Hospital, DK-2100 Copenhagen, Denmark;
2. Institute of Aerospace Medicine, Deutsche Forschungsanstalt für Luft und Raumfahrt, Cologne, Germany;
3. Department of Medical Physiology, University of Copenhagen, DK-2200 Copenhagen;
4. Department of Physiology and Pharmacology, University of Southern Denmark, DK-5000 Odense; and
5. Department of Internal Medicine and Endocrinology, Herlev University Hospital, DK-2730 Herlev, Denmark