How to Prepare for a High-Altitude Trek

Hiking · Hiking, trekking and nature · 2 min read · Researched guide · Last updated 2026-10-23

In short: Altitude sickness typically occurs above 2,500 m and fitness does not protect you. Ascend gradually (not more than about 300 m a day of sleeping height), avoid alcohol and sleeping pills early on, and descend if symptoms worsen. Severe signs such as breathlessness at rest or confusion are emergencies.

Quick facts

Know the symptoms

Acute mountain sickness (AMS) shows as headache with nausea, fatigue, dizziness, confusion or poor sleep. Fitness does not lower the risk. The life-threatening forms are HAPE (fluid in the lungs: breathlessness at rest, persistent dry cough) and HACE (brain swelling: severe headache, unsteady walking, confusion).

Prevention

• Ascend gradually and add rest days.
• Avoid strenuous activity in the first 24 hours at altitude.
• Avoid alcohol and sleeping pills for the first 24 to 48 hours.
• Drink enough, but not excessively.
• Do not ascend with symptoms.

If symptoms worsen

Descending to a lower altitude is the only definite treatment for severe AMS, HAPE and HACE. Medicines such as acetazolamide are sometimes used, but ask a doctor; do not self-prescribe from a blog.

Plan the trek

Choose an itinerary that builds height slowly, with a guide and a communication plan. See Himalayan driving and altitude, first-aid planning and examples such as Hampta Pass or Sandakphu.

Check before you go

This is a researched guide, not medical, legal or mechanical advice. Rules, permits, closures and fees change. Confirm locally before you travel.

Frequently asked questions

Read next

Rules, closures, fees and conditions change. Confirm with the relevant authority before you travel, and treat this guide as planning help, not a substitute for local advice.