Harald Engan1,2, Alexander Patrician3,4, Erika Schagatay3,5. 1. Environmental Physiology Group, Department of Health Sciences, Mid Sweden University, Östersund, Sweden. Harald.Kare.Engan@unicare.no. 2. Unicare Rehabilitation Norway, Oslo, Norway. Harald.Kare.Engan@unicare.no. 3. Environmental Physiology Group, Department of Health Sciences, Mid Sweden University, Östersund, Sweden. 4. Centre for Heart, Lung and Vascular Health, University of British Columbia Okanagan, Kelowna, Canada. 5. Swedish Winter Sports Research Centre, Mid Sweden University, Östersund, Sweden.