Why can supplemental oxygen help climbers at very high elevations?

At high elevations, supplemental oxygen is essential for many climbers because of the significant decrease in atmospheric pressure. While the percentage of oxygen in the air remains constant, the lower pressure at high altitudes reduces the partial pressure of oxygen, making it harder for the body to absorb the oxygen it needs through passive diffusion.12

In the "death zone"—typically defined as areas above 25,000 to 26,250 feet (7,600 to 8,000 meters)—this lack of oxygen, or hypoxia, becomes extreme. Without supplemental oxygen, climbers face severe physiological challenges, including:345

• Cognitive and Physical Impairment: Hypoxia can lead to confusion, poor decision-making, and a lack of muscle coordination, which are dangerous in a high-stakes environment.345
• Severe Health Risks: The body may struggle to digest food or sleep, and extreme oxygen deprivation can contribute to life-threatening conditions like high-altitude cerebral edema (HACE) or high-altitude pulmonary edema (HAPE).3

By breathing supplemental oxygen through a mask, climbers can partially alleviate these effects, helping them maintain better physical and mental function during their ascent.3