Most visitors fly into Leh, which sits at about 3,500 metres. Your body has had no time to adjust, and almost everyone feels the altitude on the first day: a headache, breathlessness on the stairs, poor sleep. With a few simple rules it passes, and you can go on to cross 5,000 m passes safely.
This article is general information, not medical advice. Talk to your doctor before travelling to high altitude, especially if you have a heart or lung condition or are pregnant.
What is acute mountain sickness (AMS)?
AMS happens when you go up faster than your body can adapt to the lower oxygen in the air. It can affect anyone, however fit. Common symptoms are:
- headache, often with one of the following
- nausea or loss of appetite
- tiredness and weakness
- dizziness
- trouble sleeping
Mild AMS is common and gets better with rest at the same altitude. Two rare but serious forms need immediate descent and medical help: HAPE (fluid on the lungs: breathlessness at rest, a wet cough) and HACE (swelling of the brain: confusion, clumsiness, extreme drowsiness).
How to acclimatise in Leh
- Rest completely for the first 24 hours. Sleep, read, drink tea. Don't explore Leh's steep lanes on day one.
- Take it easy on day two. A short, gentle walk to Shanti Stupa or the old town is fine.
- Spend at least two nights in Leh before going higher: no Khardung La, Pangong or Tso Moriri in the first 48 hours.
- Drink plenty of water (3–4 litres a day) and avoid alcohol and smoking for the first few days.
- Go up gradually. Once above 3,000 m, try not to raise your sleeping altitude by more than 300–500 m a night, and add a rest day every few days.
- Climb high, sleep low. A day trip to a pass is better than sleeping just below it on your first visit.
All our treks and mountaineering expeditions are designed around these rules, with acclimatisation days built into the itinerary.
Should I take Diamox?
Acetazolamide (Diamox) can help prevent AMS and is widely used in Ladakh. It's a prescription medicine with side effects, such as tingling fingers and frequent urination, and it is not suitable for everyone. Ask your doctor before your trip. It is not a replacement for acclimatising slowly.
When to go down
The one rule that matters most: if symptoms get worse while you rest, go down, even a few hundred metres. Never go higher with symptoms of AMS. Our guides carry oxygen and a first-aid kit, and check everyone's oxygen levels on high-altitude trips. In Leh, the SNM Hospital has experience treating altitude illness.
