Altitude sickness and how to avoid it
Altitude sickness strikes in the mountains when you climb too fast. Symptoms, how to prevent it through acclimatization, and when you absolutely must descend.
Cusco, La Paz, Everest, or any mountain city: climbing to high altitude can gift you incredible landscapes… and a headache that ruins the trip. Altitude sickness, or soroche, is very common and, although usually mild, it’s worth knowing how to prevent it and how to recognize when it becomes dangerous.
What altitude sickness is
Altitude sickness appears when the body doesn’t adapt fast enough to the smaller amount of oxygen at high elevations. Above about 2,400–2,500 meters (roughly 8,000 ft), the air has less oxygen, and the body needs time to adjust. If you climb too fast, you don’t give it that time and symptoms appear.
The cause, then, isn’t “the cold” or “the effort,” but the lack of oxygen (hypoxia) combined with too rapid an ascent.
The symptoms
Mild altitude sickness (acute mountain sickness) usually causes, as the MSD Manual notes:
- Headache (the most typical symptom).
- Nausea or loss of appetite.
- Dizziness and fatigue.
- Trouble sleeping.
- Shortness of breath on exertion.
It usually appears 6 to 24 hours after arriving at altitude and, in mild cases, improves on its own within a day or two.
How to prevent it
The key word is acclimatization: giving the body time. The most effective recommendations are:
- Climb slowly: if you can, gain altitude gradually and don’t sleep much higher each night.
- Rest on the first day after arriving; avoid intense exercise.
- Hydrate well and drink plenty of water.
- Avoid alcohol and tobacco the first few days.
- Eat light and carbohydrate-rich meals.
- In the Andes, many people use coca leaf tea as a traditional remedy to ease symptoms.
In some cases, a doctor may prescribe preventive medication (such as acetazolamide) for trips to high altitude.
When it’s an emergency
Most cases are mild, but altitude sickness can worsen. You must descend immediately and seek medical help if severe signs appear:
- Intense headache that won’t go away.
- Confusion, difficulty walking, or loss of coordination.
- Shortness of breath at rest.
- Coughing up frothy fluid or blue lips/nails.
These can be signs of edema (fluid buildup in the lungs or brain), which is an emergency. The golden rule: if you get worse, go down.
Enjoying the heights with a clear head
Altitude sickness shouldn’t scare you, but it does deserve respect. With a gradual climb, good hydration, and a little patience on the first day, most travelers avoid it or get through it without problems. Listen to your body, don’t push the pace, and remember the mountain’s most important rule: when in doubt, descending is always the right call.