It is climbing season, and many climbers must think about altitude sickness before taking on the next great challenge. Known also as acute mountain sickness, hypobaropathy, Acosta disease, puna, or soroche, altitude illness happens when your body struggles to adjust to lower oxygen levels which happen as you climb higher into the atmosphere. For most, the condition only occurs at 8,000 feet (2,500 meters) or higher, but it really varies from person to person.

Though the condition can become severe quickly, if caught before it becomes life-threatening, it can be treated. However, you will need to recognize the symptoms to avoid complications. “The best and safest way to enjoy the climb or visit to higher altitudes is to be prepared which includes knowledge about the signs and symptoms of altitude sickness and understanding what your health care provider told you to do before the climb and during if symptoms develop,” explained Dr. Albert Rizzo, American Lung Association’s Chief Medical Officer.

Here’s what you should know about altitude sickness to keep you and your loved ones safe.

Who is most at risk?

Altitude sickness occurs because the higher you climb, the thinner the atmosphere gets. This makes breathing in the same amount of air much harder, so you get less oxygen than you would at lower altitudes. If your body is unable to take the time and adjust to the difference in oxygen, altitude sickness occurs.

A person who is not accustomed to high altitudes is more likely to experience symptoms. You are also more likely to develop symptoms if you ascend quickly or stay at a high altitude for a long time. In fact, almost everyone who ascends to 11,000 feet or higher will develop altitude sickness.

The age, weight, blood pressure and respiratory capacity of an individual may also make you more susceptible to developing symptoms. Smoking, alcohol usage and the use of sedatives can also greatly increase the chances of getting altitude sickness. Having a medical diagnosis that affects your breathing can put you at greater risk as well.

What are the symptoms of altitude sickness?

Altitude sickness can cause a variety of symptoms which vary depending upon the severity. The symptoms of acute mountain sickness usually appear within the first day or so of reaching a high altitude. They usually include:

  • Headache
  • Nausea, vomiting or lack of appetite
  • Fatigue and weakness, even while resting
  • Dizzy or lightheadedness
  • Insomnia but tiredness
  • Shortness of breath
  • Swelling of the hands, feet or face

More severe forms of altitude sickness, high altitude pulmonary edema (HAPE) and high-altitude cerebral edema (HACE), may take two to five days to appear. HAPE means that severe altitude sickness has caused your lungs to fill with fluid. A persistent cough, pink or bloody sputum, fever and panting may be signs of HAPE and should be treated as a medical emergency.

If altitude sickness causes your brain to swell, it is called high altitude cerebral edema and is considered the most severe form of the illness. A headache that does not respond to medications for pain management, clumsiness, changes in consciousness and increased vomiting, numbness or dizziness signal this medical emergency.


HAPE can be deadly within 12 hours. HACE can be deadly within 24 hours. If you develop either, go to the emergency room immediately!

How is altitude sickness treated?

It is important to give your healthcare provider a detailed history, particularly about your climbing, if you suspect altitude sickness. This, combined with a physical exam and evaluation of symptoms is the only way to get a definitive diagnosis. The only way to cure altitude sickness is to stop ascending and descend to where you can breathe easier. Stopping and resting is a good idea at the first signs of being affected. If, once you have descended you are still experiencing symptoms, your healthcare provider can help you. Supplemental oxygen, hyperbaric therapy, and medications (specifically acetazolamide, dexamethasone or nifedipine), can all ease symptoms of mild altitude sickness.

Tobacco use of any kind can affect oxygen levels, which is a key concern with altitude sickness, so if you are a smoker, you should consider quitting.
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“Whether you are a regular mountain climber or just plan on visiting an altitude you may not be familiar with such as visiting Denver, Mexico City or Albuquerque, you should plan on speaking to your health care provider before traveling to these altitudes,” said Dr. Rizzo. “This is the best way to prevent or at least lessen the effects of the high altitudes and this is especially important for those who have an underlying lung disease such as asthma, emphysema or pulmonary fibrosis.”

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