1. Department of Medicine, University of Utah, Salt Lake City, Utah;
2. Faculty of Health and Life Sciences, Northumbria University, Newcastle, United Kingdom;
3. School of Sport and Service Management, University of Brighton, Eastbourne, United Kingdom;
4. Altitude Research Center, Department of Emergency Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado;
5. Department of Biology, University of Colorado, Colorado Springs, Colorado; and
6. Department of Human Physiology, University of Oregon, Eugene, Oregon