Altitude Sickness

Altitude sickness can affect even the most seasoned climbers when they're trekking in the Himalayas. In its most severe forms it is a life-threatening illness, and must be treated immediately by descent to a lower altitude.

Ascent to an altitude of 6,000 to 8,000 feet or higher puts trekkers and other tourists at risk. Flights to Lukla or to Lhasa (Tibet) take travelers to very high altitudes with no time for their systems to adjust, and treks through high mountain passes can have the same effect. Susceptibility to altitude sickness is not affected by training or physical fitness.

Altitude sickness is divided into three syndromes: acute mountain sickness (AMS), high-altitude cerebral edema (HACE), and high-altitude pulmonary edema (HAPE). Symptoms of AMS can include headache, fatigue, loss of appetite, nausea and occasionally vomiting; they may clear up if affected travelers remain at the same altitude to acclimatize. HACE and HAPE are more severe conditions, marked by lethargy, confusion and/or shortness of breath. Anyone displaying these symptoms should descend to a lower altitude without delay, and report to a medical professional as soon as possible.