| What it is | Bottled O2 via mask & regulator |
| Used above | ~7,000-8,000 m |
| Reduces | Altitude illness, frostbite risk |
| Difficulty | Advanced (expedition) |
Supplemental oxygen is bottled oxygen, delivered through a mask and regulator, that high-altitude climbers breathe to offset the thin air on the world’s highest peaks. Used widely above about 7,000-8,000 metres, it reduces the risk of altitude illness and frostbite and aids performance, though some climbers ascend the 8,000ers without it.
Why and where
It effectively lowers the altitude the body feels, easing altitude illness and frostbite risk — essential for most in the death zone during a summit bid.
Without oxygen
A small elite climbs the 8,000ers without it — far riskier, demanding exceptional acclimatization.
Frequently asked questions
Why do climbers use supplemental oxygen?
Because at extreme altitude there's far too little oxygen to sustain effort or even survive long. Bottled oxygen effectively lowers the altitude the body experiences, reducing the risk of altitude illness and frostbite, improving warmth and judgment, and making summiting the highest peaks far more achievable and survivable.
At what altitude do climbers use oxygen?
On the highest peaks, most climbers start using supplemental oxygen somewhere above about 7,000-8,000 m — particularly in the death zone above 8,000 m, where the body cannot acclimatize and deteriorates rapidly. Below that, climbers generally rely on acclimatization.
Can you climb Everest without oxygen?
Yes — it was first done by Reinhold Messner and Peter Habeler in 1978, and a small number of elite climbers still summit the 8,000ers without bottled oxygen. It is far more dangerous, demands exceptional acclimatization and fitness, and carries higher risks of frostbite and altitude illness.
Sources
- High-altitude physiology — Wilderness Medical Society
- Extreme altitude — UIAA Medical Commission