Altitude sickness planner
Pick a high place or type a height, and build a night-by-night plan of where you sleep. Nights that climb too fast are flagged, with the warning signs and when to go down.
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Where are you going?
Cusco: 3,400 m (11,150 ft)11,150 ft (3,400 m)
High (2,500–3,500 m (8,200–11,480 ft)): altitude sickness common if you arrive fastHigh (8,200–11,480 ft (2,500–3,500 m)): altitude sickness common if you arrive fast
Most people fly in from Lima (sea level). Many sleep lower in the Sacred Valley (about 2,900 m (9,510 ft)) first.Most people fly in from Lima (sea level). Many sleep lower in the Sacred Valley (about 9,510 ft (2,900 m)) first.
Warning signs
Acute mountain sickness (AMS)
Headache plus any of: nausea or vomiting, tiredness, dizziness, poor appetite, poor sleep — usually 6–12 hours after going higher.
Don't go higher. Rest at the same height; mild pain relief and fluids. If it gets worse or doesn't ease in a day or two, go down.
High-altitude cerebral oedema (HACE)
Confusion, drowsiness, odd behaviour, or unsteady walking — try walking heel-to-toe in a straight line.
An emergency: go down now, with someone, even at night. Oxygen and medical help if available.
High-altitude pulmonary oedema (HAPE)
Breathless at rest, a cough (sometimes pink froth), a much slower walk than your group, blue lips.
An emergency: go down now, keep warm and do as little effort as possible. Oxygen and medical help if available.
When to go down
- Never go higher with symptoms. Stay put until they're gone, or go down.
- Go down if symptoms get worse while you rest at the same height.
- Go down at once for confusion, clumsiness, breathlessness at rest — even 300–500 m (984–1,640 ft) lower often helps; 1,000 m (3,280 ft) is better.Go down at once for confusion, clumsiness, breathlessness at rest — even 984–1,640 ft (300–500 m) lower often helps; 3,280 ft (1,000 m) is better.
- Never leave someone with symptoms alone, and never send them down alone.
- Altitude sickness doesn't care how fit you are; fit people who climb fast get it too.
Before and during
- Climb high, sleep low: day walks higher than where you sleep help you acclimatise.
- Drink normally (pale urine), eat carbohydrates, go easy on alcohol and sleeping pills for the first nights.
- Preventive medicine (usually acetazolamide) is prescription-only: talk to a doctor or travel clinic before you go, especially if you fly or drive straight to altitude.
- If you've had altitude sickness before, you're likely to get it again at a similar pace — plan slower.
General information, not medical advice. Rules follow the Wilderness Medical Society and CDC travel guidance on preventing altitude illness; heights are rounded (checked 2026-09). Heart or lung conditions, pregnancy and young children need a doctor's advice before going high. Keep your health card up to date and see pharmacy & medicine card for buying medicine abroad.