Altitude Sickness

Preventing and responding to acute mountain sickness

Step by Step

Above about 2500 meters, altitude itself can cause illness. Acute mountain sickness feels like a bad hangover: headache, nausea, tiredness, and poor sleep, usually starting within hours of arrival. The treatment is to stop ascending, rest, drink fluids, and take simple painkillers; most people recover in a day or two. Descend promptly if symptoms worsen, and descend immediately for any breathlessness at rest, cough, confusion, or loss of coordination, which can signal dangerous brain or lung swelling: these are emergencies, and descent is the only reliable cure. Never ascend to sleep higher with symptoms. Ascend gradually, allow acclimatization days, and consider medication prescribed for prevention if you are prone.