Is it possible to ascend Mount Everest without oxygen and how does oxygen affect the ascent time?

Yes, it is possible to ascend Mount Everest without oxygen, although it is a challenging and physically demanding feat. Most climbers use supplementary oxygen above 6500 meters (21325 feet) to prevent the effects of severe hypoxia [1]. However, there have been climbers who have successfully reached the summit without the use of supplemental oxygen canisters.

Reinhold Messner and Peter Habeler were the first climbers to reach the summit of Everest without oxygen in 1978 [2]. Since then, fewer than 200 people have accomplished this feat out of the more than 4,000 individuals who have climbed Mount Everest [2]. Adrian Ballinger and Cory Richards, for example, are two climbers who aspire to reach the summit without oxygen and have attempted to do so [2].

The use of supplemental oxygen can significantly affect the ascent time on Mount Everest. The atmosphere at Everest's summit is so thin that it can only support a human at rest [2]. Climbing without oxygen at extreme altitudes presents a significant physiological challenge due to the reduced oxygen availability. It requires the body to adapt to the low oxygen levels and cope with the effects of severe hypoxia.

Here is how oxygen affects the ascent time on Mount Everest:

1. Oxygen supplementation helps climbers maintain higher oxygen levels in their blood, reducing the risk of severe hypoxia and altitude sickness.
2. With supplemental oxygen, climbers can maintain a higher level of physical performance and endurance, allowing for a faster ascent.
3. Climbers using oxygen can experience reduced fatigue and improved mental clarity, which can contribute to a faster and safer ascent.
4. The use of supplemental oxygen can also help climbers recover more quickly during rest periods, allowing for shorter breaks and a faster overall ascent time.

Learn more:

1. ABC of oxygen: Oxygen at high altitude - PMC - NCBI
2. Interview with Climbers About Reaching Mount Everest Summit Without Oxygen
3. NOVA Online | Everest | First Without Oxygen