At What Altitude Do You Need Oxygen When Hiking?

At high altitudes, like the top of Mount Everest, the air becomes thin and oxygen becomes scarce, making the work of climbing and mountaineering that much more challenging. In the worst-case scenario, altitude sickness sets in, bringing with it nausea and problems with motor functions.

If you are planning on hiking at a higher altitude, you need to know whether altitude sickness is a danger you might encounter, and whether or not you need supplemental oxygen with you.

At What Altitude Do You Need Oxygen When Hiking?

You definitely need oxygen if you are hiking in the “Death Zone” – higher than 8000 meters or 26,000 feet. At that level, your body can’t function without supplemental oxygen. However, many people develop the symptoms of altitude sickness much earlier: above 2,500 meters or 8,200 feet.

8,000 meters is really high. For a frame of reference, Mount Everest is 8,839 meters tall.

It is impossible to know in advance whether you will develop altitude sickness, but the risk exists for hikers at relatively low altitudes. Even if altitude sickness is not severe or dangerous at lower elevations, it is an uncomfortable reality for many people.

If you have a lower fitness level, and/or your body is accustomed to a lower elevation, you might need oxygen to treat moderate altitude sickness at altitudes above 2,500 meters, which isn’t that high at all. For a frame of reference, the city of Quito in Ecuador, where people work and live happily, is at an elevation of 2,830 meters.

Experienced climbers, physically fit people, and those who normally live at higher elevations will have an easier time avoiding altitude sickness than inexperienced couch potatoes who live at sea level, and the variance is huge.

For hiking, be cautious and bring oxygen if you worry that you will need it. There is no downside to being prepared.

What is Altitude Sickness?

Altitude sickness is caused by low levels of oxygenation in the blood. The air at higher elevations contains less oxygen, which causes a drop in oxygen levels in the blood.

The human body relies heavily on oxygen to perform several essential functions, so when an oxygen shortage is detected your body starts to function differently to preserve resources. This causes the uncomfortable symptoms we associate with altitude sickness.

Most people experience a sense of fatigue and weariness, possibly accompanied by nausea, a lack of appetite, and motor function difficulties. The symptoms are similar to dehydration, and resting with a drink of water is sufficient in some cases to treat mild altitude sickness.

In more severe cases, in the Death Zone above 8,000 meters, professional climbers (even at peak fitness levels) can experience severe altitude sickness that can require evacuation and hospitalization. Oxygen is a temporary treatment that can alleviate the majority of symptoms.

Can You Train Yourself to Avoid Altitude Sickness?

Yes. There is a reason that the native people of Nepal, the sherpas, are some of the best mountaineers in the world. They were born and raised at high altitudes, and their bodies are both genetically suited and physically trained to hike at elevation.

Even if you never reach sherpa-level, it is possible to train your body to tolerate higher altitudes through exposure.

Several factors affect your vulnerability to altitude sickness:

1. Physical Fitness

Physically fit people process oxygen more efficiently. The better your cardiovascular health, the more easily your body will adjust to the lack of oxygen. From your body’s perspective, there isn’t that much difference between feeling winded during a long run and feeling winded during a slow hike at a high altitude.

The more physically fit you are, the better you will withstand the effects of altitude sickness, and the higher you can climb without a need for supplemental oxygen.

2. Genetics

Some people are just genetically better at tolerating high altitudes, particularly people who come from populations that have lived at high altitudes for hundreds of years. The native people of the Himalayas and the Andes Mountains show higher resistance to altitude sickness, even when controlling for other factors.

You might not know whether you are prone to altitude sickness until you test it by hiking there, but genetics do play a role.

3. Typical Elevation

Where you live normally and spend most of your time is a large factor when it comes to vulnerability to altitude sickness.

If you live in San Diego, your body has spent a long time adjusting to regular oxygen levels at sea level (an elevation of 0 meters). In a way, it has become “spoiled” by high oxygen and it is less prepared to adapt.

In contrast, if you live in Boulder, Colorado, you are already at an elevation of 1,621 meters or 5000 feet. You’re not exactly in mountaineering territory, but your body is used to using less oxygen even in everyday life.

You can train your body to tolerate altitudes better by regularly exercising at higher altitudes. Ideally, if you want to take on a high-altitude hike, you will work your way up by doing several hikes at increased elevations to allow your body to adjust.

Do I Need Oxygen for Hiking?

The answer is an absolute yes for hikes above 8,000 meters or 26,000 feet, but it is harder to calculate for hikes at lower elevations because there are so many factors to consider.

Oxygen is unlikely to be medically necessary for hikes under 6,500 meters, or 22,000 feet. Although many people experience altitude sickness at these elevations, you can treat mild to moderate altitude sickness without oxygen by resting, staying warm, and drinking water. Altitude sickness is usually resolved by sleeping rather than by oxygen.

It’s also worth noting that oxygen isn’t necessarily a panacea; even with supplemental oxygen, some climbers continue to experience the symptoms of altitude sickness.

As a rule of thumb, if you are worried about altitude sickness between elevations of 2,500 meters and 8,000 meters, it might give you peace of mind to bring an oxygen canister. They are lightweight, and even if they are not medically necessary, they can bring you some comfort and relief when you are feeling sick.

Which Popular Mountains Require Climbers to Use Oxygen?

You need oxygen to reach the top of mountains higher than 8,000 meters or 26,000 feet. That includes Mount Everest and K2.

Kilimanjaro and Mt. Denali are both around the 6,000-meter mark, where a majority of climbers will experience some kind of altitude sickness, but not all climbers require oxygen.

Mt. Pajaro in Patagonia and Macchu Picchu in the Andes Mountains are both between 2000 meters and 2500 meters, where altitude sickness is possible but very treatable with rest and fluids.

According to the Cleveland Clinic, at elevations higher than 3000 meters or 10,000 feet, 3/4 of people will experience mild symptoms of altitude sickness, although this doesn’t always require oxygen. Many climbers take oxygen at elevations where there is a significant risk of symptoms and discomfort, even if it is not medically necessary.

How Do You Use Oxygen While Climbing?

Supplemental oxygen comes in small canisters with a mouth attachment. You simply press your face against the mouthpiece and inhale.

The canisters aren’t heavy or expensive. They come in 2-liter, 5-liter, and 10-liter canisters. The 2-liter canister sells for $40.

If you are mountaineering Everest, this will be a necessity, but even if you are just going on a road trip to a city at a higher elevation, supplemental oxygen could help relieve headaches, nausea, and fatigue.

Hiking With Oxygen at High Altitudes

Although you can’t breathe the air at elevations above 8,000 meters, and climbing to the top of Everest or K2 requires oxygen to be able to survive, this is rare and there aren’t many climbs that literally require oxygen.

However, many climbers use supplemental oxygen at lower elevations to treat moderate altitude sickness. Elevations above 2,500 meters can cause shortness of breath, fatigue, and nausea in even experienced hikers.

Although rest and water are proven treatments for acute, mild altitude sickness, oxygen is another helpful tool that can bring more rapid relief.

Most hikers don’t necessarily need supplemental oxygen, but it’s great to have, especially if you are worried about enjoying your hike in an unfamiliar state or country at a higher elevation. Altitude sickness is uncomfortable and can be dangerous, and oxygen canisters are affordable and lightweight gear.

Last Update: 20. May 2022
About the Author

My name is Thomas, and I love the outdoors. I'm currently living in Germany and I would like to encourage my readers to go outside with this blog. Here you can read more about me.