Avoid Altitude Illness While Exercising

Skier in the Mont Blanc region

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If you train at low altitude and plan to exercise at high altitude, the threat of mountain sickness is very real. Learn more about the risks associated with altitude illness and get practical tips and precautions to make your trip to the mountains safe.

What Is Altitude Illness?

Above 8,000 feet (2,424 m), many vacationers suffer from altitude illness or acute mountain sickness (AMS). There are varying degrees of illness and the most common is altitude sickness.

This condition generally occurs between 6,000 and 10,000 feet and causes mild symptoms such as a headache, dizziness, nausea and poor sleep. Symptoms often clear up in a day or two, but if they don't you may need to go to a lower altitude until you feel better. Going from low elevation to high elevation quickly will increase your odds of feeling altitude illness.

Types of Altitude Illness

Other, less common types of altitude illness include high-altitude pulmonary edema (HAPE) and high-altitude cerebral edema (HACE). Symptoms of HAPE include difficulty breathing, chest tightness, cough, and fatigue. Symptoms of HACE include confusion, lack of coordination, stumbling and poor balance.

Both of these conditions occur most often over 10,000 feet and are serious conditions that require immediate medical attention.

Other Risks of High-Altitude Exercise

Those who travel to altitude to exercise may not always experience altitude illness, but there are other risks associated with high-altitude exercise to be aware of.

Decreased Availability of Oxygen

As you move from sea level to higher altitude the air pressure decreases and your ability to easily take in oxygen is reduced. Because it is harder to get oxygen to your lungs, you compensate by increasing your breathing rate, depth, and heart rate. Until you acclimate you may find that what you can easily do at home is more difficult at altitude.


While the reduced availability of oxygen is the primary reason that exercising at altitude is more difficult, another factor that reduces performance and causes altitude illness is dehydration. The lower humidity and increased breathing rate at altitude cause you to lose more moisture with every exhalation than at sea level. Even a slight loss of fluid (2-3 pounds of water lost through sweating and even breathing) can result in a notable decrease in athletic performance.

Dehydration is a culprit in most cases of acute mountain sickness. Symptoms such as a headache, mild dizziness, nausea, insomnia, and irritability can indicate dehydration and should not be ignored.

In many cases, problems can be prevented by taking simple precautions. If you plan to travel to and exercise at, high altitude you should hydrate well by drinking before you feel thirsty. Avoid alcohol and caffeine because they are diuretics that can lead to dehydration.

Heat Illness

Summer in the mountains may not always be cooler than at low elevations. Heat illness falls into several categories including heat cramps, heat exhaustion, and heatstroke.

Heatstroke is a medical emergency. It strikes suddenly and with little warning. Signs of heatstroke can include a core body temperature above 105 F, hot, dry skin, a very fast pulse, and confusion or disorientation.

Stopping the activity and cooling the body are the key treatments for heat exhaustion.

Heat cramps are painful muscle spasms along with faintness/dizziness/weakness. They usually develop after several hours of exertion and sodium (and other electrolytes) depletion. Replacing lost electrolytes and fluids is usually the best treatment.

Increased Sun Exposure

Direct sun exposure at altitude adds to the effects of dehydration and can lead to serious sunburns. Sunburns occur more easily at altitude (especially for the fair-skinned) and sunburn can lower the skin's ability to cool itself.

To protect from the effects of sun exposure, avoid exercising when the sun is at its most intense (from 11-2 PM). If you are out in the middle of the day, protect yourself with appropriate clothing, sunblock (SPF 30 +) and sunglasses.

How to Prevent High Altitude Illness

  • Move to higher altitudes gradually to give your body time to acclimate and adjust. After 8000 feet, ascend no more than 1000 feet per day.
  • Don't go any higher if you have a headache or lack of coordination or other symptoms of altitude illness.
  • Sleep at a lower altitude than you are during the day, if possible.
  • Ask your doctor about medications for altitude illness (acetazolamide (Diamox, Dazamide) would be helpful for you.
  • Carry rain gear/warm clothing because mountain weather can change quickly.
  • Drink plenty of liquids while exercising (16-32 oz/hour or more in hotter weather).
  • Dress in layers, and wear light-colored clothes that wick moisture, like Cool-Max.
  • Use sunscreen to help prevent sunburn.
  • Rest and try to cool off if you feel your performance drops quickly.
  • Do not drink alcohol/caffeine before or immediately after exercising at altitude. Keep in mind that it is easier to prevent many altitude-related symptoms than to treat them once they develop.
7 Sources
Verywell Fit uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By Elizabeth Quinn, MS
Elizabeth Quinn is an exercise physiologist, sports medicine writer, and fitness consultant for corporate wellness and rehabilitation clinics.