Travelers going by plane from sea level to high elevations such as Denver, Aspen, or Mexico City may suddenly experience shortness of breath, fatigue, headaches, nausea, and other symptoms resembling flu. This condition, called acute mountain sickness (AMS), is the most common type of altitude sickness. It can occur at elevations as low as 5,000 feet, where it is likely to last only a day or so, but is more common above 8,000 feet. At elevations over 10,000 feet, three out of four people will have symptoms.

Not everyone feels sick at higher altitudes, and there is no way to predict a person’s highest comfortable altitude. Being physically fit is not necessarily a protection. Indeed, athletes accustomed to working out daily at low altitudes may be the first to become ill if they continue intense workouts at high altitudes.

Susceptibility to AMS is greater in those under 40 years of age, perhaps because they are more likely to exert themselves at high altitudes. Skiers, hikers and others who go above 8,000 feet risk getting more severe symptoms of AMS.

At higher altitudes, a serious medical emergency known as high-altitude pulmonary edema (HAPE) may develop. This life-threatening condition is due to an accumulation of fluids in the lungs and can lead to death if not treated immediately. Those afflicted must immediately descend at least 2,000 to 3,000 feet and then be treated in a medical facility.

Symptoms of Altitude Sickness

  • Increased rate of breathing
  • Headache
  • Lethargy
  • Fatigue and insomnia
  • Loss of appetite
  • Dizziness and nausea
  • Vomiting
  • Shortness of breath and rapid heartbeat accompanying physical exertion
  • Impaired thinking. Symptoms usually begin 12 to 24 hours after arrival, are worse at night when respiration slows down, and typically decrease in severity by the third day.

What Causes Altitude Sickness?

As mountain climbers know, altitude sickness results from a lack of oxygen caused by going too high, too fast. Barometric pressure decreases as you go higher—that is, the air gets thinner—and you inhale less oxygen per usual breath. Trying to compensate for this, you breathe more deeply. The likelihood of symptoms increases the higher you go.

What If You Do Nothing?

Most people who develop acute mountain sickness will feel well within two to three days by taking it easy and avoiding strenuous activity. However, if you go up to 10,000 feet and higher and exert yourself without adequate acclimation, the more serious high-altitude pulmonary edema (HAPE) can develop.

Home Remedies for Altitude Sickness

If you are going to the Rocky Mountains or another high-altitude region, you can probably alleviate symptoms of AMS quickly by taking the following measures.

  • Acclimatize and take it easy. Spend your first day at high altitudes relaxing. Avoid even moderate exercise until you get accustomed to the new heights.
  • Do not smoke and avoid drinking alcohol. Smoking and alcohol consumption increase the risk of dehydration and decrease respiration rate during sleep and can worsen symptoms of altitude sickness.
  • Drink extra water. Drink as much as you can to remain properly hydrated, at least three to four quarts. Your urine should be clear and copious. Avoid alcoholic beverages. The fast, deep breathing you must do at higher altitudes will tend to dehydrate you, an effect that alcohol intensifies.
  • Eat foods that are high in carbohydrates.
  • Get headache relief. Acetaminophen or an NSAID (such as ibuprofen) can be taken for headache.
  • Don’t go up until symptoms go down. If you start showing symptoms of moderate altitude sickness, don’t go any higher until they decrease—or descend a few hundred feet to a lower altitude.


The only established preventive strategy is to prepare for destinations above 8,000 feet. Spend a day acclimatizing at a lower level, or climb to a new level at a rate of 500 to 1,000 feet daily with an occasional day of rest. This allows the body to operate with decreased oxygen by increasing its depth of respiration, releasing more red blood cells to carry oxygen, and producing more of a particular enzyme that helps trigger the release of oxygen from hemoglobin to the body tissues.

Beyond Home Remedies: When To Call Your Doctor

It’s a good idea to seek medical advice in advance if you are planning to travel to extreme altitudes (8,000 feet or higher), particularly if you will be exerting yourself.

What Your Doctor Will Do

If you are affected by altitude sickness and/or if acclimatization takes too long or is not effective, your doctor may recommend acetazolamide (Diamox), a prescription medication that may reduce the incidence and severity of altitude sickness by as much as 75 percent. The drug improves pulmonary function and allows you to breathe faster and to obtain more oxygen without the adverse effects of breathing too strenuously.


The Complete Home Wellness Handbook

John Edward Swartzberg, M.D., F.A.C.P., Sheldon Margen, M.D., and the editors of the UC Berkeley Wellness Letter

Updated by Remedy Health Media

Publication Review By: the Editorial Staff at

Published: 19 Oct 2011

Last Modified: 10 Mar 2015