Altitude Sickness in Nepal: Symptoms, Prevention, and the Golden Rules for Trekkers

Direct answer: Altitude sickness (acute mountain sickness, AMS) in Nepal is caused by ascending too fast above ~2,500 m. Prevent it by climbing high but sleeping low, gaining no more than ~500 m of sleeping altitude per day above 3,000 m, and drinking 3–4 litres of water daily. The golden rule: if symptoms worsen, do not go higher — descend immediately.

What altitude sickness is

At altitude, air pressure and oxygen drop. Above roughly 2,500 m the body may struggle to adapt, causing AMS. Severe forms — HAPE (fluid in lungs) and HACE (brain swelling) — are medical emergencies. Lukla (2,860 m), Namche (3,440 m), and Everest Base Camp (5,364 m) all sit in the danger zone.

Early symptoms to watch

• Headache (the most common sign)
• Nausea or loss of appetite
• Fatigue, dizziness
• Trouble sleeping
• Shortness of breath at rest (in severe cases)

How to prevent AMS

1. Acclimatize: include rest days (e.g. Namche, Dingboche).
2. Climb gradually: ≤500 m sleeping gain/day above 3,000 m.
3. Hydrate: 3–4 L water/day; avoid alcohol early on.
4. Eat well: carbohydrates fuel altitude exertion.
5. Consider medication: acetazolamide (Diamox) — only with a doctor’s advice.

The golden rules

• Do not ascend with symptoms.
• Descend if symptoms worsen — even 500 m helps.
• Never leave a sick person alone.
• Know the evacuation plan (heli, insurance) before you start.

Frequently asked questions

Does fitness prevent altitude sickness?
No. Even elite athletes get AMS. Pace, not fitness, is the protection.

Is Diamox required?
No, but it aids acclimatization for some. Consult a physician before your trip.

How fast should I descend?
At the first sign of severe symptoms, descend at least 500–1,000 m without delay.

Key takeaways

• AMS hits above ~2,500 m from ascending too fast.
• Prevent with gradual ascent, acclimatization days, hydration.
• If symptoms worsen — stop, descend, get help.

Published by the TravellingNepal Editorial Desk. Health guidance summarized from standard wilderness-medicine acclimatization principles; consult a travel-medicine doctor before high-altitude treks.