Hypoxic Training Systems for Climbing at Extremely High Altitude: A Survey of Current Practice.

Zachar, Cormac, Colin K. Grissom, Scott E. McIntosh, and Andrew M. Luks. Hypoxic training systems for climbing at extremely high altitude: A survey of current practice. High Alt Med Biol. 00:00-00, 2025. Background: Anecdotal report suggests increasing numbers of climbers are using hypoxic training systems to prepare for expeditions to extremely high elevations but there is little systematic information regarding their incorporation into training approaches. Methods: An anonymous survey of mountaineers who have attempted to climb mountains >6,000 m in the past 20 years. Results: Responses from 385 individuals were included in the analysis; the majority reside in North America. In total, 24.6% of respondents have used a hypoxic training system during sleep or exercise training. Climbers who use these systems cite multiple reasons for their use, including reducing the risk of acute altitude illness, improving exercise capacity at high altitude, and increasing the odds of summit success. Climbers obtain information on employing these systems from multiple and varied sources. Perceptions about the utility of hypoxic training systems are more positive among people who use the systems for sleep or exercise training compared with those who do not. Conclusions: Nearly 25% of climbers in our survey used hypoxic training systems to prepare for mountains >6,000 m and hold generally positive views of the utility of these systems. Further research is warranted to assess their effectiveness and refine protocols for incorporation into training programs.