1. Sports
Send to a Friend via Email
You can opt-out at any time. Please refer to our privacy policy for contact information.

All About Acute Mountain Sickness

How to Avoid High Altitude Illness


Climbers descend Crestone Needle in the Sangre de Cristo Mountains, Colorado.

If you develop symptoms of AMS, descend to a lower altitude and you'll feel lots better.

Photograph © Spencer Swanger

Mike, a climbing partner who just moved back to Colorado from Seattle three weeks ago, and I were in Rocky Mountain National Park in Colorado a couple days ago. Our plan was to climb the sweeping northeast face of Spearhead, a dramatic 12,575-foot-high fin of granite in upper Glacier Gorge below Longs Peak. We left the parking lot early in the morning and hiked a quick five miles to Black Lake, and then started up the last uphill mile to the upper basin. As we hiked, Mike began lagging farther and farther behind me.

Classic Acute Mountain Sickness Symptoms

When Mike finally reached me below the cliff at almost 12,000 feet, he complained about shortness of breath, a headache, and a touch of nausea. All are classic symptoms of acute mountain sickness (AMS), the most common and least serious form of altitude-induced illness.

Thin Air Causes Hypoxia

As we climb to higher elevations, the air pressure and the amount of oxygen in the thinning air decreases and forces us to breathe harder and deeper to inhale enough oxygen. Available oxygen at 18,000 feet is 50% less than that at sea level. When we can't get enough oxygen, we develop hypoxia or insufficient oxygen in our red blood cells for normal functioning. AMS, the first stage of altitude illness, primarily affects the brain.

Headaches are Most Common Symptom

Acute mountain sickness symptoms, which can occur within an hour of arriving at a high altitude, includes headache, nausea, vomiting, insomnia, loss of appetite, fatigue, and general lethargy. Headaches, the most common AMS symptom, occur in 90% of people that travel to altitudes above 8,000 feet from lower elevations like sea level. The symptoms usually take four to eight hours to develop. Neither age nor general fitness is a factor in the development of AMS. It can strike anyone who travels to a higher elevation. Symptoms may be worse at night.

AMS Symptoms are Non-Specific

AMS symptoms are not specific, so it can be difficult to assess the patient. If he is, however, complaining of the usual symptoms and has recently arrived at a high altitude, then it's a good bet that he is suffering from acute mountain sickness.

Treat AMS Promptly

Whenever you're climbing in the high mountains, pay attention to both yourself and your climbing partners for signs of acute mountain sickness. While AMS by itself does not lead to health issues, if it is ignored and untreated it can lead to more serious and potentially life-threatening medical problems like high altitude pulmonary edema (HAPE) and high altitude cerebral edema (HACE). If AMS is promptly treated, the symptoms will go away and the patient will require no medical attention.

Follow these specific treatments to manage acute mountain sickness:

  • Descend to a lower elevation. A quick descent is the fastest way to alleviate AMS symptoms.
  • Don't climb higher until you feel better.
  • Sleep low. Climb high. Follow this old climber's adage to avoid AMS.
  • Drink plenty of liquids to stay hydrated.
  • Eat well with carbohydrates comprising 70% of your diet.
  • Avoid strenuous exercise like rock climbing or hard hiking.
  • Stay alert for AMS symptoms to avoid complications.
  • Take over-the-counter medications like ibuprofen to manage headaches and other symptoms.
  1. About.com
  2. Sports
  3. Climbing
  4. Stay Safe Climbing
  5. All About Acute Mountain Sickness -- How to Avoid High Altitude Illness

©2014 About.com. All rights reserved.