Altitude Sickness: When Your Body Rebels at Over 5,000 Feet

The Beautiful (and very high) Rocky Mountains
Copyright: Elizabeth R. Rose

When it comes to traveling to high-altitude destinations like Denver and Aspen, Colorado, or the Swiss Alps, altitude sickness affects almost one out of three people.

Generally speaking, this temporary illness occurs when a person quickly travels from a place with a low elevation to one with a high elevation—or vice verse. This usually occurs above 5,000 feet, though some might not experience altitude sickness until at least 10,000 feet in elevation.

Ultimately, altitude sickness is unpredictable. It can affect anyone from the young, fit hiker to the elderly traveler, and those who suffer from it one trip may not get sick the next time. Knowing how to prevent altitude sickness before it starts and how to detect it once it sets in can go a long way in making your trip to a high-elevation destination more comfortable and enjoyable.

Definition and Symptoms of Altitude Sickness

The first step in understanding altitude sickness is to be able to define what it is. According to WebMD,

"Altitude sickness occurs when you cannot get enough oxygen from the air at high altitudes. This causes symptoms such as a headache and not feeling like eating. It happens most often when people who are not used to high altitudes go quickly from lower altitudes to 8,000 feet or higher. For example, you may get a headache when you drive over a high mountain pass, hike to a high altitude, or arrive at a mountain resort." 

While altitude sickness may not set in at the same altitude for all people, most experiencing this unique high-elevation illness typically experience the same symptoms:

  • Frequent headaches
  • Queasiness and lack of appetite
  • Shortness of breath
  • Nausea
  • Fatigue
  • Dizziness
  • Trouble sleeping or waking frequently

You may have altitude sickness yet not have all of these symptoms.

Some people may experience a general lethargy or get tired more easily at higher elevations due to a minor case of altitude sickness just because you can't get enough oxygen from the air.

Preventing and Treating Typical Altitude Sickness

Whether or not you are prone to altitude sickness, there are a few precautions you should take when climbing thousands of feet in elevation in a short amount of time. Taking these quick steps can help you prevent the possibility of experiencing this ailment when you arrive at your destination.

  • Drink plenty of water to prevent dehydration.
  • Ascend and descend gradually, maybe over a day or two.
  • Spend a day or the first night at an altitude slightly lower than where you plan to be active.
  • Take preventive medications that might help with altitude sickness.
  • Limit alcoholic beverages.

The first step to treating altitude sickness, if you do get it, is to acknowledge that this is what's affecting your body. Once you first feel the symptoms, you should immediately increase your intake of fluids and avoid strenuous activity. Within a day, you should acclimate to the altitude and be able to resume normal activities, but you might still want to avoid too much hiking and remember to get plenty of rest.

If you already have heart or lung problems, experience debilitating symptoms, or become concerned about your body’s response to high altitudes, be sure and contact a medical professional. This information is meant as an informal guide to altitude sickness and not medical advice.

High Altitude in the United States

If you're planning on traveling to a high-altitude destination in the United States, it may be a good idea to prepare for your trip by taking some of the above preventative measures so that you can avoid getting altitude sickness when you arrive at your destination. You might want to alter your travel plans to prepare your body for a trip to a very high altitude place by staying in a slightly lower city first. For example, if you're traveling to Aspen, you might first want to spend a day or two in Denver before continuing on to Aspen.

​If you live at or close to sea level (0 feet elevation), you may want to be prepared for altitude sickness when traveling to these destinations:

  • Leadville, Colorado: 10,430 feet
  • Aspen, Colorado: 7,900 feet
  • Santa Fe, New Mexico: 7,000 feet
  • Mount Mitchell, North Carolina: 6,684 feet
  • Jackson Hole, Wyoming: 6,500 feet
  • Denver, Colorado: 5,280 feet