The science behind sleeping at altitude

Simulated altitude sleep is based on the well-established Live High / Train Low model: athletes spend extended time in a reduced-oxygen environment to stimulate altitude-related adaptations, while continuing to complete key training sessions at lower altitude where intensity and power output can be maintained.

The studies below include foundational Live High / Train Low research, controlled simulated-altitude sleep studies, haemoglobin mass research, elite-athlete altitude interventions, Olympic-performance reviews and broader physiological reviews. Together, they show that when altitude exposure is applied consistently and at an appropriate dose, it can support endurance-related adaptations including increased haemoglobin mass, red cell volume, oxygen-carrying capacity, VO₂max and, in some studies, improved race or time-trial performance.

Haemoglobin mass is especially important because it helps determine how much oxygen the blood can carry. Several altitude studies show that increases in haemoglobin mass are associated with improvements in aerobic capacity. However, VO₂max and performance are influenced by more than haemoglobin alone, including cardiac output, plasma volume, muscle oxygen extraction, training quality, recovery, sleep quality, iron status and individual response.

Individual responses vary. The research does not suggest that altitude exposure is a shortcut or a guaranteed performance boost; rather, it supports altitude sleep as a validated tool within a structured endurance-training and recovery program.

Key findings from the research

Neya et al., 2013 reported that 21 nights of simulated altitude exposure at approximately 3000 m produced meaningful endurance-related adaptations, including increased haemoglobin mass and improved aerobic capacity.

Levine & Stray-Gundersen, 1997 helped establish the Live High / Train Low model, showing that living at altitude while training lower can improve aerobic capacity while preserving training quality.

Gore et al., 2013 reviewed altitude training and haemoglobin mass using the optimised carbon monoxide rebreathing method. The key takeaway is that altitude exposure can increase haemoglobin mass, although the magnitude of response depends on the altitude dose, athlete status and methodology used.

Wehrlin et al., 2006 found that 24 days of Live High / Train Low increased haemoglobin mass, red cell volume and VO₂max in elite endurance athletes, reinforcing the link between repeated altitude exposure and improved oxygen-carrying capacity.

Garvican-Lewis et al., 2013 adds further evidence from simulated Live High / Train Low research, showing how controlled hypoxic exposure can be used with athletes in practical training environments without requiring permanent relocation to natural altitude.

Chapman et al., 2023 reviewed 25 years of Live High / Train Low implementation in the context of Olympic medal performance, providing a modern overview of how altitude strategies have evolved and why altitude exposure remains relevant for elite endurance preparation.

The Live High / Train Low physiological and performance review brings the evidence together, highlighting the main mechanisms and practical considerations: improved oxygen transport, potential VO₂max and endurance-performance benefits, variability between responders and non-responders, and the importance of applying the correct altitude dose over enough time.

Research catalogue