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How to Prevent Altitude Sickness

Colorado is a great place to live and visit for anyone who enjoys mountain activities. Unfortunately, if you don’t let your body adjust when traveling to higher elevations, you may experience altitude sickness.

Three Types of Altitude Sickness

Altitude sickness is divided into three categories that may coexist. The first, and by far most common, is acute mountain sickness or AMS, typically occurring within 1 to 24 hours of ascending to altitude. Common symptoms include headache, fatigue or exhaustion, lightheadedness, loss of appetite, insomnia or restless sleeping, and nausea. The duration of these symptoms generally is 24 to 48 hours and will usually improve if one does not ascend any higher.

The second category is high altitude pulmonary edema, also known as “HAPE.” With HAPE, one develops fluid in the lungs, usually 24 to 72 hours after ascending to altitude. In addition to AMS symptoms, one may experience severe coughing, shortness of breath that is out of proportion to exertion level, and a fullness sensation in the chest. HAPE is an urgent medical problem requiring immediate descent to a lower altitude and seeking medical care.

The third category of altitude sickness is high altitude cerebral edema, also known as “HACE.” With HACE, one develops swelling of the brain’s tissues, usually 24 to 72 hours after ascending to altitude. In addition to AMS symptoms, one may experience profound fatigue, weakness, inability to walk with a normal gait, lack of concentration, confusion, and delirium. HACE requires immediate descent to a lower altitude and emergency medical care.

Treatment and Prevention

A common question from patients is how they can prevent altitude sickness. Here are a few tips:

  • Reduce risk by ascending slowly to higher altitudes. Gradual increase in elevation over several days allows the body to acclimate;
  • Increase your physical exertion gradually as you go higher in elevation;
  • Stay well-hydrated and avoid consuming alcohol for the first few days at altitude.

If you are predisposed to altitude sickness or are ascending to altitude rapidly and exerting yourself vigorously, ask your doctor for preventive medications such as acetazolamide (the brand name is “Diamox”).

Rest and moving to a lower altitude are the best treatments for developing AMS symptoms. In addition, hydrating and taking headache medications such as acetaminophen or ibuprofen may be helpful for mild headaches.

If you develop symptoms concerning HAPE or HACE, seek emergency medical assistance.

Traveling to Colorado and enjoying the mountains can be great fun. However, you can make your trip more pleasant by gradually increasing your elevation and activity level, maintaining good hydration, avoiding alcohol, and seeking immediate medical attention if you develop concerning symptoms.


Felicia Longenecker, MD
Internal Medicine

As a board-certified Internal Medicine physician, Dr. Longenecker focuses on preventative medicine. Her goal is to keep patients in their best possible health to enjoy life, which means addressing diet, exercise habits, and mental health.

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