1. Zurich Center for Integrative Human Physiology, Institute of Physiology, University of Zurich, Zurich, Switzerland;
2. Swiss Federal Institute of Sports, Magglingen, Switzerland;
3. Foeto-Maternal Haematology Group, Department of Obstetrics, University Hospital of Zurich, Zurich, Switzerland;
4. Intensive Care Unit, University Hospital of Zurich, Zurich, Switzerland;
5. Department of Environmental Physiology, School of Technology and Health, Royal Institute of Technology, Solna, Sweden