Practical Management: PDF OnlyHydration Strategies for Physical Activity and Endurance Events at High (>2500 m) Altitude A Practical Management ArticleTrease, Larissa FACSEP*,†; Singleman, Glenn MBBS, DipComm*; Windsor, Jeremy MB ChB, MD, DCH‡; Allan, Stuart BMBS, BMedSci, MRCGP, DiMM, DTM&H§; Albert, Edi MB ChB, MSc, MRCGP, DIMM*,¶Author Information *University of Tasmania, School of Medicine, Healthcare in Remote and Extreme Environments (HREE) Program, Tasmania, Australia; †Orthopaedics ACT, Woden, Australia; †Chesterfield Royal Hospital, Chesterfield Derbyshire, United Kingdom; ‡Faculty, Diploma in Mountain Medicine, United Kingdom; and §Alice Springs, Northern Territory, Australia Corresponding Author: Larissa Trease, BMedSci (Hons), MBBS (Hons), FACSEP, University of Tasmania, School of Medicine, Healthcare in Remote and Extreme Environments (HREE) Program, Tasmania, Australia ([email protected]). The authors report no conflicts of interest. Received September 28, 2020 Accepted January 11, 2021 Clinical Journal of Sport Medicine: March 01, 2021 - Volume Publish Ahead of Print - Issue - doi: 10.1097/JSM.0000000000000919 Buy PAP Metrics Abstract A growing number of adventurous athletes are seeking new challenges through endurance events or physical activities held at high altitude (>2500 m). This coincides with a significant increase in the numbers of trekkers who ascend into the world's mountains. Altitude itself influences and complicates the athlete's effective and safe hydration. This article considers the physiology of adaptation to altitude and the effects on hydration at altitude compared with sea level, reviews the “ad libitum versus programmed hydration” controversy in conventional endurance event hydration, examines the evidence for extrapolation of sea level hydration strategies to the high-altitude environment, and synthesizes these disparate factors into a set of practical recommendations for hydration management during high-altitude physical activity. The guidelines will be relevant to participants of physical activity at altitude and health care staff who may care for them in the preparation or performance phases of their adventure. Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.