Altitude and Acclimatization on the Upper Mustang Trek

Elevations Along the Route

The ascent profile is gradual on the trekking route, which is one of its advantages over faster overland options. Trekkers gain elevation slowly over 5–6 days from Jomsom to Lo Manthang, which allows the body to adapt. The 4WD Overland Tour covers the same distance faster, so those itineraries include deliberate acclimatization stops.

AMS: What It Is and What to Watch For

Acute Mountain Sickness is caused by reduced oxygen availability at altitude. It's not a matter of fitness – strong, fit people can develop AMS just as readily as unfit ones. The key variables are rate of ascent and individual physiology, which you can't predict from previous trekking experience at lower altitudes.

Early AMS symptoms include headache (the most common indicator), fatigue beyond what the day's walking warrants, loss of appetite, nausea, dizziness, and disturbed sleep. These symptoms appearing together above 2,500m are a clear signal to stop ascending.

High Altitude Pulmonary Edema (HAPE) and High Altitude Cerebral Edema (HACE) are the dangerous progressions. HAPE symptoms include a persistent cough, breathlessness at rest, and chest tightness. HACE presents as severe headache unresponsive to ibuprofen, loss of coordination (ataxia), and altered consciousness. Both require immediate descent – not rest, not water, not Diamox. Descent.

Acclimatization Rules for the Upper Mustang Trek

Above 3,000m, don't ascend your sleeping altitude by more than 300–500m per day, and build in a rest day for every 1,000m gained. The trekking itinerary for the Tiji Festival Trek respects this. Don't try to shortcut it.

Drink 3 to 4 litres of water per day. Mustang is extremely dry and dehydration compounds altitude effects. Avoid alcohol in the first few days above Kagbeni – it accelerates dehydration and masks AMS symptoms.

Diamox (acetazolamide) is commonly used as a prophylactic. Dosage is typically 125–250mg twice daily, starting 24 hours before ascending above 2,500m. It works by stimulating faster breathing, increasing oxygen saturation. Side effects include tingling in the extremities and increased urination. It's preventive, not a treatment for severe AMS. Consult your doctor before the trek.

Emergency Protocol and Evacuation

Your guide carries a pulse oximeter on our treks and monitors oxygen saturation at each camp. If your SpO2 drops below 80% at rest with symptoms, or if HACE or HAPE is suspected, evacuation is initiated immediately. Don't argue with your guide about this.

Helicopter evacuation from Lo Manthang to Pokhara takes approximately 45 minutes. Evacuation by jeep to Jomsom is an option in less acute cases. Adequate travel insurance covering high-altitude helicopter evacuation is a requirement for booking with us. An uninsured evacuation runs into thousands of dollars.

Learn more about what to pack including a basic altitude first-aid kit. Read our Best Time to Visit guide for how season affects altitude conditions.