Altitude for first-timers
What AMS can feel like, who should stay lower, and why descend is the rule — not a slogan.
Altitude is the part of Nepal that does not care how fit you are. Acute mountain sickness (AMS) can start above about 2,500 m. It often feels like a hangover you did not earn: headache, nausea, no appetite, poor sleep. That is a signal to stop going up, not to “push through.” People with significant heart or lung disease, recent surgery, or a pregnancy should talk to a doctor who understands altitude before they book a high trek. This page is not a diagnosis and not a prescription. Acetazolamide (Diamox) is a conversation with a clinician, not a trail snack. Some travelers use it; some should not. We will not tell you to take it. The rule that actually keeps people alive is simple: if symptoms get worse as you go higher, you go down. Guides cancel summit days for this reason. A first trek can stay lower — Poon Hill, Ghorepani, or a hotel-based trip — and still be Nepal.
What it can feel like
Headache, queasiness, dizziness, and sleeping badly. Worse: confusion, a wet cough, or you cannot walk a straight line. Those are emergency signs. Descend and get help.
Who should not go high first
If a doctor has told you to avoid altitude, believe them. There are excellent Nepal trips that never sleep above Pokhara.
Descend is the rule
Rest days are built into good itineraries. Extra rest is not weakness. Walking down with a headache is competence.