How Acute Mountain Sickness Causes Headaches

No one wants a headache to ruin their much-anticipated vacation exploring the South American Andes or skiing in the Rocky Mountains. Yet, within 6 to 12 hours of reaching a high altitude, people can develop acute mountain sickness — which is classically characterized by a headache and other unpleasant symptoms.

Let's learn more about the headache and other symptoms of acute mountain sickness, and how you can prevent it and get on with your lovely travels.

Tourist admiring the view from the top of a mountain in Loen, Norway
© Marco Bottigelli / Getty Images


According to the American Headache Society, almost one in four people who ascend to 2,600 meters or 8,500 feet above sea level will develop symptoms of acute mountain sickness — of which, headache, especially migraines and tension headaches, are a dominant symptom. Besides headache, other symptoms of acute mountain sickness include:

  • loss of appetite
  • nausea or vomiting
  • feeling dizzy or light-headed
  • sleeping difficulties
  • fatigue or weakness

The symptoms of acute mountain sickness may be mild and resolve on their own or progress to an even more serious, potentially fatal illness called high-altitude cerebral edema. This condition is characterized by confusion and difficulty with balance, due to brain swelling.

Another high-altitude illness that can develop is called high-altitude pulmonary edema. This condition is characterized by symptoms like difficulty breathing, cough, and chest tightness or congestion — all related to fluid buildup in a person's lungs.

Headache of Acute Mountain Sickness

According to the American Headache Society, the headache in someone with acute mountain sickness is generally throbbing, like a migraine, and located all over a person's head or on the forehead. It may develop within 6 hours to 4 days after reaching a high altitude and can last up to 5 days. The headache is usually worse with exertion, coughing, straining, or lying flat. Other symptoms that may be associated with the headache include:

  • flushing of the face
  • redness of the eyes
  • photophobia (i.e., sensitivity to light)

While the headache of acute mountain sickness is classically attributed to low oxygen levels, there appears to be more factors involved, as oxygen does not alleviate the headache.


Having designated rest days and ascending slowly are the best ways to prevent acute mountain sickness. In terms of medication for prevention, a healthcare provider may prescribe acetazolamide (Diamox). It's usually taken at least one day prior to ascending and continued until a person reaches their highest altitude. Acetazolamide may cause numbness and tingling and an aversion to carbonated drinks. Also, it should not be taken by people who are allergic to sulfa.

Other measures to prevent acute mountain sickness include:

  • drinking ample water to avoid dehydration
  • sleeping in lower elevations (i.e., at night, sleep in lodging at a lower elevation than the mountain you are hiking or skiing on during the day)


The headache of acute mountain sickness usually responds to ibuprofen or sumatriptan, especially if it resembles a migraine.

Take Away Message

The key to enjoying your high-altitude vacation is prevention. Water, rest, and a reasonable travel plan is your best bet here. Also, talk with your healthcare provider about whether you should take preventive medication, like acetazolamide.

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  • Dodick DW. (2008). Altitude, Acute Mountain Sickness, and Headache.

  • Fiore DC, Hall S, Shoja P. Altitude illness: risk factors, prevention, presentation, and treatment. Am Fam Physician. 2010;82(9):1103-10.

By Colleen Doherty, MD
 Colleen Doherty, MD, is a board-certified internist living with multiple sclerosis.