Altitude sickness (Acute Mountain Sickness or AMS) is the most common health concern for trekkers in Nepal. It can affect anyone above 2,500 meters, regardless of age or fitness level. Proper acclimatization is the best prevention.
What Is Altitude Sickness?
At high altitudes, the air contains less oxygen. Your body needs time to adjust to reduced oxygen levels. If you ascend too quickly, you may develop symptoms ranging from mild headache to life-threatening conditions.
Symptoms of AMS
Mild AMS
- Headache (the most common symptom)
- Nausea or loss of appetite
- Fatigue and weakness
- Dizziness or lightheadedness
- Difficulty sleeping
Severe AMS — Seek Immediate Help
- Severe headache not relieved by painkillers
- Persistent vomiting
- Confusion or disorientation
- Loss of coordination (ataxia)
- Breathlessness at rest
- Gurgling or crackling sound when breathing (signs of HACE or HAPE)
Prevention — The Golden Rules
- Ascend gradually: Above 3,000m, gain no more than 300-500m of sleeping altitude per day
- Take rest days: Every 3rd day, or after every 1,000m gain, stay at the same altitude for an extra night
- Climb high, sleep low: Take day hikes to higher elevations but return to sleep at a lower altitude
- Stay hydrated: Drink 3-4 liters of water per day at altitude
- Avoid alcohol and sleeping pills: Both suppress breathing at altitude
- Listen to your body: Never ascend with symptoms of AMS
Treatment
- Mild symptoms: Rest at the same altitude until symptoms resolve. Take ibuprofen or paracetamol for headache. Stay hydrated.
- Moderate symptoms: Descend 500-1,000m immediately. Do not continue ascending.
- Severe symptoms (HACE/HAPE): Descend immediately. Administer supplemental oxygen if available. Emergency helicopter evacuation may be needed.
Diamox (Acetazolamide)
Diamox is a prescription medication that helps prevent altitude sickness by stimulating breathing. Many trekkers take it as a preventive measure. Consult your doctor before the trip — Diamox is not suitable for everyone and may cause side effects including tingling in fingers and toes, increased urination, and altered taste.
Which Nepal Treks Have Altitude Risk?
| Trek | Max Altitude | AMS Risk |
|---|---|---|
| Everest Base Camp | 5,364m | High |
| Three Passes Trek | 5,545m | Very High |
| Annapurna Base Camp | 4,130m | Moderate |
| Langtang Valley | 3,870m | Moderate |
| Poon Hill Trek | 3,210m | Low |
| Upper Mustang | 3,800m | Moderate |
How Eco Holiday Asia Manages Altitude Safety
- All itineraries include proper acclimatization days built into the schedule
- Licensed guides are trained in altitude sickness recognition and emergency response
- First-aid kits with basic altitude medications on every trek
- Emergency coordination for helicopter evacuation when needed
- Pre-trek briefing covers altitude awareness for every trekker
Important: Travel insurance covering helicopter evacuation above 4,000m is required for all treks with Eco Holiday Asia.
Contact us to discuss altitude preparation for your specific trek. Our guides are happy to answer questions about acclimatization schedules.
More resources: Trekking in Nepal | Best Time to Trek
