Altitude Sickness: Symptoms, Prevention & Treatment

Instructor: Rachel Torrens

Rachel is a Nurse Practitioner with experience working as a high school teacher, skin surgery center, and as a family NP.

Scaling one of the highest peaks in the world may be on your bucket list, but before climbing, you need to know about altitude sickness (AS). In this lesson, learn all about AS, including symptoms, treatments, and prevention tips.

What Is Altitude Sickness?

As a child, you may have said, 'Mom, I am off to climb Mount Kilimanjaro!' But in all your imaginary expeditions, you probably never encountered altitude sickness (AS). In its mildest form, AS is a manageable condition, but it can rapidly escalate into several life-threatening conditions.

AS is a real danger for any person considering traveling above 8,000 feet. AS occurs because as you increase in elevation, air pressure lowers and the oxygen level in the air decreases. As you know, oxygen is pretty essential for human life. So, if the air you are breathing has less oxygen, your body has less oxygen. Furthermore, when at these high altitudes, individuals are usually performing exercise, such as hiking, which increases the rate of oxygen consumption by the body's tissues.

When you start depriving your body of oxygen, it does not take long for symptoms to occur. With mild AS, people report having a headache and feeling fatigued. Some individuals suffer nausea and may vomit. In fact, many people liken it to having a terrible hangover. For reasons unknown, some cases of AS rapidly progress to life-threatening conditions.

This sign warns hikers of the symptoms associated with altitude sickness.
high elevation warning sign

Complications of Altitude Sickness


This abbreviation stands for high altitude cerebral edema. Edema means there is a lot of fluid in a space in the body where there should be little or no fluid. So, cerebral edema means there is extra fluid in and around the brain. Naturally, this fluid squishes the brain against the skull, increasing intracranial pressure. Thus, the symptoms a person experiences will be neurologic in nature: confusion, difficulty walking properly, and extreme lethargy. If a person develops HACE, he or she must receive treatment within 24 hours or death is extremely likely.


This abbreviation stands for high altitude pulmonary edema. Again, there is fluid build-up, but this time, it is in the lungs. As you are aware, lungs should be filled with oxygen, not fluid. The symptoms of HAPE include difficulty breathing, even at rest, and coughing. A person can die even more quickly from HAPE, sometimes within hours.

This hiker has puffiness of the face, a sign of fluid retention, and of onsetting altitude sickness.
Man with AS at mountain top

Treatment of Altitude Sickness

The most beneficial thing that can be done is to quickly get the person suffering from AS, HACE, or HAPE to a lower altitude. Immediate descent helps to alleviate the symptoms of all these conditions because the air at a lower altitude has a higher percentage of oxygen.

In mild cases of AS, painkillers, such as Tylenol, can be given to help alleviate headache. Anti-nausea medications may also be given to help stomach upset. For moderate to severe cases of AS, or if HACE is suspected, the steroid dexamethasone may be given to rapidly alleviate symptoms. If HAPE is suspected, the drugs nifedipine or any phosphodiesterase-5 inhibitor may be used. Finally, supplemental oxygen, if available, is also helpful in treating AS.

Treatment for altitude sickness includes rapid descent, appropriate medicines, and supplemental oxygen.
Treatment of AS

Prevention of Altitude Sickness

Better than treating a condition, is preventing it in the first place! The following are ways to prevent AS:

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