Engaging patients in high-quality, compassionate health care

Understanding and Preventing Altitude Sickness

by Eric Zacharias, MD
Internal Medicine Specialist
Boulder Medical Center

Colorado is a great place to visit for mountain activities. Unfortunately, some people experience altitude sickness when traveling to the high county for what they hope will be a fun time. In this post I will summarize information about altitude sickness and how to prevent and treat it.

Three Categories of Altitude Sickness

Altitude sickness is divided into three categories which may coexist. The first, and by far most common, is acute mountain sickness or AMS. This usually occurs 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 as long as 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 the symptoms of AMS, 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 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 tissues of the brain usually 24 to 72 hours after ascending to altitude. In addition to the symptoms of AMS, one may experience profound fatigue, weakness, inability to walk with a normal gait, lack of concentration, confusion, and delirium. HACE is an emergency and warrants immediate descent to lower altitude and emergency medical care.

Treatment and Prevention

A common question from patients is how they can prevent altitude sickness. Most importantly, one can reduce risk by ascending slowly to higher altitudes—a gradual increase in elevation over several days allows the body to acclimate.  Also, you should gradually increase your physical exertion level at altitude for the first few days. Lastly, you should stay well-hydrated and avoid consuming alcohol for the first few days at altitude.

If you have a history of predisposition to altitude sickness or will be ascending to altitude rapidly and exerting yourself vigorously, you can ask your doctor for preventive medications such as acetazolamide (brand name is “Diamox”).

If you develop symptoms of AMS, rest and moving to a lower altitude are the best treatments.  For mild headaches, maintaining hydration and taking headache medications such as acetaminophen or ibuprofen may be helpful.

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

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

About Dr. Eric Zacharias

Dr. Eric Zacharias specializes in Internal Medicine at Boulder Medical Center. In addition to general Internal Medicine expertise, Dr. Zacharias provides updates about preventative interventions such as vaccines for patients who are traveling. He is also a Colorado state-certified Yellow Fever vaccine provider.