Department of Exercise and Sport Sciences, University of Copenhagen, Copenhagen, Denmark; Laboratoire Performance et Santé en Altitude, Université de Perpignan, Font-Romeu, France; Zürich Center for Integrative Human Physiology (ZIHP), University of Zürich, Zürich, Switzerland; Ecole Nationale des Sports de Montagne, site de l'Ecole Nationale de Ski et d'Alpinisme, Chamonix, France; Laboratoire de Pharm-Ecologie Cardiovasculaire, Université d'Avignon, Avignon, France; Zürich Center for Integrative Human Physiology (ZIHP), University of Zürich, Zürich, Switzerland; Food & Nutrition & Sport Science, Gothenburg University, Sweden carsten.lundby@access.uzh.ch.