A product of the collaboration between a sports physiologist and mountain sports enthusiast and one of the world’s most distinguished mountain-sport athletes, this study examines the main body systems involved in exercise at high altitudes, discussing their capacity for adaptation and their limits. It looks at some of the common problems that affect high-altitude athletes, including bronchial hyperresponsiveness, hypoxia, and oxidative stress, and presents essential anatomical and physiological elements clearly and concisely through annotations and full-color photographs and figures. Each chapter also features Kilian Jornet’s comments on his strategy for dealing with his own body’s limitations and his training regimen, which he supplements with physiological data.