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      A Good Head for Heights: Recognizing and Preventing Altitude Illness

      Love mountains? Our NOLS Wilderness Medicine Institute classes about high-altitude medicine are often the students' favorites, as every class contains at least a few aspiring mountaineers.

      Lurking behind every mandatory summit photo, though, can be a heap of pain and adversity. Hypothermia, frostbite, deli belly, blisters, sore muscles, bad weather, falling rocks and ice, sometimes falling people—there's a whole array of potential obstacles aligned against you.

      And the higher you climb the thinner the air gets, leaving you vulnerable to altitude illness. You can beat many of the obstacles with guts and persistence, but the only way to beat altitude illness is by being smart. If you try to grit through altitude sickness, you can get into deep trouble. Sometimes you die.

      Altitude illness

      It's about oxygen, you see. You need oxygen to live; it's the most basic thing, and when you climb into the thin air you rob yourself of this life-giving element.

      Most people will tolerate a sudden trip to 10,000' without difficulty, but higher than that your body needs time to adapt. Your heart rate and breathing will speed up, and your blood will develop higher-than-normal amounts of red blood cells. The rest of your cells slowly change too, so that they use oxygen more efficiently.

      The Wilderness Medicine Society advises that in order to stay at "low risk", climbers should move camp no more than 500m (1,640') higher every subsequent day after climbing to 3,000m, (approx. 10,000') to allow for their biology to catch up with the mountain's physics.

      The mild form of altitude illness is called AMS, or acute mountain sickness. It's a headache, plus other symptoms that resemble the flu or maybe a hangover: nausea, fatigue, loss of appetite, difficulty sleeping, etc.

      AMS isn't dangerous, but it should signal a clear warning to the climber to stop climbing. AMS means you are ascending faster than you can adapt, and it's time to pause until feeling better. Most AMS sufferers (who stop climbing) feel better in a day. If the symptoms don't improve in 24 hours, you should head down into thicker air. 

      The serious forms of altitude sickness, the deadly ones, carry the impressive acronyms HACE and HAPE. They stand for high-altitude cerebral edema and high-altitude pulmonary edema—brain swelling and lungs filling with fluid. Not good, either one, and both are treated by a rapid descent to lower elevations until symptoms improve.

      AMS sufferers resting

      HACE, the brain swelling, is identified early as a worsening headache that begins to affect the climber's sense of balance. If someone cannot walk a straight line, heel to toe, or balance on one foot, then they need to start descending immediately before the HACE progresses to vision problems, blindness, confusion, seizures and death.

      HAPE starts as shortness of breath accompanied by a dry cough. As the lungs continue to fill with fluid, the shortness of breath will worsen, the climber will develop a wet, gurgly cough, collapse and eventually die.

      Note that HACE and HAPE are independent problems, and either one requires an immediate descent. People tend to ignore their symptoms, however, whether from summit fever, or not wanting to appear weak, or misdiagnosis. They continue to climb, which only makes these problems worse. HACE and HAPE will not go away without descent.

      If you're planning on climbing a high mountain, then make sure you have time to spare on your agenda and climb at a safe rate. Up to 3,000m first, then 500m per day after. Your doctor might prescribe Diamox for you, which can offer some protection against AMS, but it's not a miracle drug by any means. Oxygen is still oxygen, and you still need to breathe it.

      If you want to learn more about these conditions, a good starting point is the Wilderness Medicine Society's consensus paper on the topic. Even better, sign up for a NOLS WMI class. We'll study and practice dealing with all the medical challenges you might face on your next adventure.

      Bottom line, it always feels great to have the confidence that comes from knowing you're well prepared.

      Top photo by Steve Hicks/Flickr; bottom photo by Jeferonix/Flickr.

      Posted on at 12:45 PM

      Tagged: AMS, HACE, HAPE, WMI of NOLS, Wilderness Medicine Institute, altitude sickness and mountaineering

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