Altitude sickness on Nepal treks: a guide’s protocol

Short version: Altitude sickness is manageable, not mysterious. Climb slowly, sleep low, drink 4 litres a day, and treat any warning sign seriously. I carry a pulse oximeter on every trek and I have one unbreakable rule: if it's getting worse, I take you down. Altitude always wins an argument.

What it is

Above roughly 2,500m your body has less oxygen to work with. Mild acute mountain sickness (AMS) brings a headache, poor sleep and low appetite. At that level it's common and fine. The danger is when it progresses. The good news is that it's very preventable with the right pace.

How I prevent it

• Slow ascent. I don't push your sleeping altitude up too fast. This is why acclimatisation days exist, and why I keep them.
• Climb high, sleep low. Rest days aren't idle. You hike up and come back down to sleep.
• Hydration. Around 4 litres of water a day. Alcohol stays off the menu up high.
• Daily monitoring. I carry a pulse oximeter and check oxygen saturation, especially above 4,000m.

When to take Diamox

Carry it on every high trek even if you don't plan to use it. Many trekkers start a preventive dose before the highest days; I'll advise based on how you're acclimatising. It's a help, not a substitute for a sensible pace.

The rule I never break

Severe headache that won't clear, loss of coordination, or confusion means I bring you down immediately. No summit, no pass, is worth it, and coming down almost always fixes it fast. I also carry emergency contacts and know the evacuation options on every route. That's exactly why travel insurance covering helicopter evacuation is mandatory on my treks.

The acclimatisation day that prevents most of this is built into my 13-day Manaslu Circuit at USD 960.

Worried about altitude on your trek? Message me on WhatsApp. I'll talk you through the plan honestly.