How to Treat and Prevent Altitude Sickness

December 05, 2023

Whether a hitting the slopes or scaling new heights while hiking, heading for the mountains often means leaving behind the higher concentrations of oxygen found in the air at lower elevations. If you’re not careful, a case of altitude sickness could ruin your trip. Fortunately, there are many ways to treat and prevent common symptoms.

What Is Altitude Sickness?

Altitude sickness, also called elevation sickness mountain sickness, occurs when you move to a higher altitude too quickly. The higher you go, the thinner the air gets, meaning it has less oxygen. If your body has difficulty adjusting to the reduced oxygen, you can experience a number of unpleasant and even life-threatening symptoms.

Symptoms usually begin at elevations of 8,000 feet above sea level. At this level, each breath you take contains 75% of the amount of oxygen you get at sea level. Even if you’re fit, you can experience shortness of breath if you’re not used to the elevation. As you move higher, the mountain air contains less and less oxygen. At 12,000 feet, you’re only getting 60% of the oxygen at sea level.

Mild Altitude Sickness: Acute Mountain Sickness

The mildest and most common form of altitude sickness is called acute mountain sickness (AMS). This condition is characterized by a number of unpleasant but non-life-threatening symptoms, including:

Nausea/vomiting
Headache that is not relieved by over-the-counter pain medicine
Dizziness or lightheadedness
Fatigue/weakness
Loss of appetite
Trouble sleeping

The first thing to do if you experience symptoms of AMS is either stop ascending or, when possible, descend to a lower elevation and rest until your symptoms resolve.

A prescription medication called acetazolamide (Diamox) may be used to speed your recovery or prevent symptoms in the first place. Acetazolamide makes you breathe faster and metabolize more oxygen, which raises your blood oxygen. This altitude sickness medication is particularly helpful at night when respiration naturally slows down.

More Serious Forms of Altitude Sickness

AMS should always be taken seriously, since sometimes it can develop into more serious forms of altitude sickness, namely high altitude pulmonary edema (HAPE) and high altitude cerebral edema (HACE).

HAPE occurs when altitude sickness causes your lungs to fill with fluid. This condition is a life-threatening emergency that requires immediate medical attention. Symptoms of HAPE include:

Chest tightness or fullness
Shortness of breath, even while resting
Excessive fatigue
Blue or gray lips and fingernails
Coughing, which may produce a frothy, pink fluid
Rattling, gurgling or other noises when breathing
Fever (a temperature above normal but less than 101° Fahrenheit)
Death, in advanced cases

HACE, the most severe form of altitude sickness, happens when altitude sickness causes the brain to swell. As such, HACE is a highly dangerous condition that requires emergency care. Symptoms of HACE include:

Worsening headache and vomiting
Loss of coordination (ataxia)
Rapid heart beat
Exhaustion
Disorientation, memory loss and visual hallucinations
Slurred speech
Loss of consciousness
Blurred vision
Coma and death, in advanced cases

If you ignore the milder symptoms of AMS, your condition can develop into either HAPE and/or HACE, which can be fatal within 12-24 hours. As a result, identifying and treating even mild cases of altitude sickness is important to prevent more severe illness and complications.

Prevention Is Better Than Cure

The good news is that altitude sickness is very preventable. If you make gradual changes in altitude, you’ll help your body adjust to the thinner air and reduce your chances of developing symptoms. You can also take acetazolamide to help prevent the onset of altitude sickness symptoms.

Not everyone adapts to changes in elevation in the same way, but four tips can help prevent or reduce symptoms:

Increase your altitude by less than 1,000 feet a night. Try staying somewhere for a day to give your body time to adjust.
Every time you ascend an additional 3,000 feet, spend a second night at that elevation before resuming your climb.
Try to limit physical exertion during your first few days at higher altitudes.
Stay well hydrated the entire time you are at higher altitudes.

And remember, if you experience symptoms of altitude sickness, you can prevent them from getting worse by stopping your climb up that mountain.