How to Prevent Altitude Sickness

 How to Prevent Altitude Sickness

Let’s imagine for a moment that we are climbing a mountain. The higher up the mountain that we go, the less oxygen that is in the air. As a species, humans are pretty good at adjusting to different altitudes up to around 8,000 feet providing we do it gradually. If we go higher than 8,000 feet, we put ourselves in danger of developing symptoms from the change in altitude.

There are two different types of symptoms regarding altitude sickness; non-life-threatening and life-threatening. The non-life-threatening symptoms are what is known as acute mountain sickness and will improve if you descend quickly. At the same time, simply having a rest can clear the symptoms and allow a climber to continue on their ascent.

The life-threatening symptoms are the ones that develop at high altitudes and can develop into fatal illnesses if they are not taken seriously. Some of these possible illnesses include:

  • High-altitude cerebral edema (HACE) – the brain swells with extra fluid which means the brain is unable to function properly
  • High-altitude pulmonary edema (HAPE) – fluid accumulates in the lungs
  • High-altitude retinal hemorrhage (HARH) – can cause eye damage
  • Coma and death are the most serious consequences

What are the Symptoms of Altitude Sickness?

If we take what we have learned above, we can break this down to better show what symptoms accompany which illness. While some symptoms can be of no concern, there are some that you must take very seriously as I have explained. The most serious symptoms are caused by the lack of oxygen in the blood.

The symptoms of acute mountain sickness usually occur 8-36 hours after ascent and can include:

  1. Headache
  2. Nausea or vomiting
  3. Dizziness
  4. Fatigue
  5. Trouble sleeping
  6. Loss of appetite

High-altitude cerebral edema will usually develop after the symptoms of acute mountain sickness above. The symptoms are not always immediately noticed and they may not be seen as severe as they are due to it affecting the brain. In many cases, it is a companion that notices the symptoms in their friend. The symptoms of high-altitude cerebral edema include:

  1. Strong headache and vomiting
  2. Staggered walking
  3. Confusion
  4. Exhaustion
  5. Hallucinations
  6. Unable to think clearly
  7. Changes in behavior
  8. Coma

As a climber reaches higher altitudes and the lungs receive less oxygen, it can cause the blood vessels in the lungs to constrict which leads to higher pressure in the arteries. Because of this, fluid leaks from these vessels into the lungs. The symptoms of high-altitude pulmonary edema include:

  1. Tight chest
  2. Extreme fatigue
  3. Unable to catch your breath
  4. Blue/gray lips and fingernails
  5. Coughing – possibly producing frothy fluid
  6. Fever
  7. Rattling or gurgling noises when breathing

In terms of high-altitude retinal hemorrhage, the main symptom is blurred vision although this is rarely noticed unless the area of the eye that provides the most detailed vision (the macula) is involved.

How to Diagnose Altitude Sickness

The key to preventing a serious illness is to recognize the early symptoms. Failure to do so can be life-threatening. The most obvious of these early symptoms is a headache. In many cases, a headache can be relieved by resting and taking a mild pain reliever. If the headache does not go away or you are showing signs of other symptoms of acute mountain sickness, the illness can be diagnosed without any tests.

If the person is hallucinating, having difficulty walking a straight path, or trouble thinking, you should assume that they have high-altitude cerebral edema. These climbers should descend straight away and seek medical care. Once in medical care, an MRI scan may be done to confirm the suspicions as these can show swelling of the brain.

Sometimes, the hardest to diagnose early is high-altitude pulmonary edema as the only early symptom present maybe fatigue. It should be a cause for concern if symptoms such as a rapid heart rate, shortness of breath while resting, and difficulty exercising are shown. Once in medical care, an X-ray would be taken which would show any signs of fluid in the lungs.

High-altitude retinal hemorrhage can be diagnosed by a doctor who examines the eye with a hand-held instrument called an ophthalmoscope.

How to Prevent Altitude Sickness

As I mentioned at the start of the article we are fairly good at adapting to the changes in oxygen but we must ensure that these changes occur gradually. Doing so will reduce the chances of any altitude sickness from developing. Altitude sickness usually gets worse at night when you’re sleeping. It’s a good idea to do a higher climb during the day and then return to a lower altitude to sleep, especially if you plan on climbing more than 1,000 feet in one day.

There are generally four guidelines that you must remember if you are planning a climb above 10,000 feet. These are:

  1. Never climb more than 1,000 feet in altitude per night
  2. Spend a second night at an elevation every time that you have increased altitude by 3,000 feet
  3. During the first few days of the climb, limit your physical exertion
  4. Drink plenty of fluids throughout the climb

As soon as you start to feel any symptoms, stop immediately, assess the situation, and descend if needed. If all that you are feeling is a slight headache then a short rest and ibuprofen will usually be enough to clear it up.

Treating Altitude Sickness

If you are experiencing symptoms of acute mountain sickness you should stop until the symptoms clear up. If the symptoms are more severe and point towards a more severe illness, you need to reduce altitude as quickly as you can safely do so. The longer that you remain at this altitude, the worse the symptoms will get and it could be fatal. Avoid anything that may slow your breathing such as alcohol, sleeping pills, or narcotic pain medications. Once you have descended you should seek medical care immediately.

Final Thoughts

Different people will react differently to the changes in altitude which makes it hard to predict exactly how an individual may react. Remember to take it slow. Don’t try climbing too high in a short amount of time and if you have any existing medical conditions, talk to your doctor before attempting to climb.


  2. Healthline

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