Altitude Sickness - Sali Trekking Archives Altitude Sickness - Sali Trekking Archives

Altitude Sickness

Altitude sickness is the human body’s reaction to atmospheric pressure and a reduction of the concentration of oxygen present in the air. As you climb higher into the mountains, your body gradually adapts to the reduced amount of oxygen in the air. The appearance of altitude sickness symptoms shows that your body has increased its altitude level faster than it can acclimatize to the corresponding change in atmospheric pressure and reduction in oxygen. In trekking, altitude acclimatization processes are different for each trekker.

Whilst trekking in Nepal anyone can fall ill with high altitude sickness regardless of their body shape, experience and previous mountain trekking experience. There’s no need to fear high altitude sickness, but it’s very important that you know how to avoid it, how to recognize it and how to act correctly in the event that you encounter symptoms of altitude sickness.

In rare cases, symptoms of altitude sickness may begin to appear starting from 2,400 meters above sea level, but an increased risk of high altitude sickness sets in starting from the 3,500 meter mark. The high risk or mountain zone starts from 5,500 meters. This is why mountain airports in Nepal like Lukla and Jomsom are located at an altitude of 2,700 -2,900 meters.

The primary symptoms of Acute Mountain Sickness (AMS) are:

-Loss of appetite
-Fatigue and weakness
-Restless sleep
-Shortness of breath
-Swelling of the face and hands.

Mild altitude sickness symptoms are experienced by about up to 20% of trekkers at altitudes of up to 3,000 meters above sea level.

At extreme altitudes, above 4,500 meters, Acute Mountain Sickness can turn into High Altitude Pulmonary Edema (HAPE) or High Altitude Cerebral Edema (HACE) which are both very serious.

High Altitude Pulmonary Edema (HAPE) symptoms include: serious fatigue, shortness of breath and dry cough, shortness of breath at rest, rapid and shallow breath, frothy or pink mucus possible, gurgling, rasping sound when breathing, pressure, heavy feeling in the chest, restlessness, rapid pulse, possible fever, cyanosis – blue or gray lips and indescribable lethargy.

High Altitude Cerebral Edema (HACE) symptoms include: powerful headache which doesn’t pass using painkillers, loss of coordination (ataxia), vomiting, apathy, fatigue, indifference, walks as if drunk, behavioral changes, confusion, hallucinations, cramping fits, short-term blindness and numbness or paralysis of individual body part.

HACE is the most dangerous form of high altitude sickness. It progresses rapidly and requires quick action to prevent the trekker’s death. You may only have a few hours time to successfully implement rescue measures depending on the degree of seriousness of HACE.


Ascending slowly is the best way to avoid altitude sickness. Avoiding strenuous activity in the first 24 hours at high altitude reduces the symptoms of AMS. When trekking above 3,000 meters be sure to give yo
urself extra days to acclimitize which will allow your body to adjust to the changes in atomospheric pressure and oxygen. Alcohol and sleeping pills are respiratory depressants, and thus slows down the acclimatization process and should be avoided. Alcohol also tends to cause dehydration and exacerbates AMS. Diamox is a drug that can be taken before you begin trekking to help with altitude sickness symptoms. Please speak to a doctor to learn more about Diamox.


The best way to treat altitude sickness symptoms is to descend. With Acute Mountain Sickeness it is best to descend at least 400-500 meters or to the previous altitude at which there were no symptoms. With HAPE
and HACE, one should descend immediately at least 500-1,000 meters. Trekkers should rest for a day or two and drink lots of fluids. If sysmptoms have completely disappeared, the trekker can ascend again. If symptoms continue to worsen the victim should continue to descend or be evacuated.

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