Altitude Sickness

Altitude Sickness” refers to a group of illnesses that result from a lack of oxygen when someone is at high altitude. The most common form is acute mountain sickness (AMS).

What are the symptoms of Altitude Sickness?

If you have AMS, you can experience headache, insomnia, tiredness, and shortness of breath for two to five days while your body is getting used to being at high altitude. AMS is a warning signal. More serious conditions, involving fluid in the lungs or on the brain, can be fatal within hours.

How can I get Altitude Sickness?

AMS is rare below 2,400 meters, but you should be aware of it if you will be ascending above 2,000 meters. High altitude and rapid ascent increase the incidence and severity of AMS. It occurs in 40 percent of those who ascend rapidly to 3,000 meters and in 75 percent of those who ascend rapidly to 4,500 meters.

How can I prevent Altitude Sickness?

Rapid ascent increases your risk of developing symptoms. Once you are above 2,000 meters, ascend gradually.

“Climb high and sleep low.” You can climb more than 500 meters in a day as long as you come back down and sleep at an altitude no more than 300 meters higher than the altitude of the previous night.

Stay well hydrated and eat a diet high in carbohydrates and low in salt.

  • People who have chronic conditions like obstructive airway disease, congestive heart failure, pulmonary hypertension, or sickle-cell anemia can experience severe medical complications at high altitude. Those who have epilepsy, cardiac arrhythmia, or sleep apnea should also be cautious. Pregnant women should not ascend beyond 3,500 meters.
  • If you will be flying directly into a location at high altitude, speak with your travel medicine specialist about taking Diamox® as a preventative medication.

What is the treatment for Altitude Sickness?

Do not ascend further while you are experiencing AMS. Rest, over-the-counter painkillers like ibuprofen or aspirin, and plenty of fluids are usually sufficient to help you with symptoms while your body adapts to the altitude. In more serious cases, some people may need supplemental oxygen and to descend to a lower altitude. Avoid alcohol and other sedatives.

Acetazolamide (Diamox®) is a prescription medicine that can reduce the incidence and severity of AMS by helping you acclimatize faster. It does not mask the symptoms of AMS and can cause some minor side effects (e.g. frequent urination, tingling lips, fingers, and toes). It does not prevent AMS from becoming more serious if you continue to ascend while you still have symptoms.

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