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, we go 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) — headache, poor sleep, low appetite — is common and usually fine. The danger is when it progresses. The good news: it's very preventable with the right pace.

How we prevent it

• Slow ascent. We don't gain sleeping altitude too fast. This is why acclimatization days exist — and why we keep them.
• Climb high, sleep low. Rest days aren't idle; we 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 → we descend 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 — which is exactly why travel insurance covering helicopter evacuation is mandatory on my treks.

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