Acute Mountain Sickness

By Marisa Ramiccio. May 7th 2016

Adventurers and thrill seekers alike enjoy scaling the tallest mountains and hiking the toughest terrain just to push their limits and do what’s never been done. But that exciting rush can easily turn into danger if acute mountain sickness, or AMS, sets in. In this article, you’ll find helpful information on AMS for your visit to higher altitudes.


Acute mountain sickness is an illness that can affect mountain climbers, hikers, skiers and people who travel at high altitudes. The symptoms can be mild or life-threatening and will surely stop mountaineers from reaching their destination.


Acute mountain sickness is brought on by a mixture of low pressure and low oxygen levels, which are found at high altitudes. Those who ascend to a higher altitude too quickly or exert themselves too much while doing so are at a higher risk of developing acute mountain sickness.

Those who live at or near sea level or who have had acute mountain sickness before are also more likely to develop it.

It’s important for those who are mountain climbing, hiking or skiing at high altitudes to acclimate to the elevation. If they can ascend slowly and let their bodies get used to the altitude change, there’s a lesser chance that they’ll develop serious symptoms of acute mountain sickness.


The symptoms of acute mountain sickness can range from mild to severe but in most cases the symptoms tend to range from mild to moderate. Those symptoms include:

  • Headache
  • Dizziness or lightheadedness
  • Fatigue
  • Difficulty sleeping
  • Loss of appetite
  • Rapid heartbeat
  • Nausea or vomiting
  • Difficulty breathing
  • Decreased coordination

These symptoms can show after 12-24 hours of ascent. The symptoms usually worsen at night but should dissipate after about three days. Those with mild acute mountain sickness should be able to get rid of the symptoms by taking medication. However, those who display moderate symptoms will need to descend a few hundred to a few thousand feet and take an advanced medication.

In some cases, acute mountain sickness will be severe enough that a person may display the following symptoms in addition to the ones already mentioned:

  • Inability to walk
  • Shortness of breath while at rest
  • Fluid buildup in the lungs
  • Decreased consciousness or confusion
  • Pale complexion or a bluish tint to the skin
  • Coughing, chest tightness or congestion
  • Coughing-up blood

Severe acute mountain sickness should be treated as a medical emergency and immediate medical attention, as well as a hasty descent of two to four thousand feet, should be sought.


A good test for checking for moderate acute mountain sickness is the sobriety test of walking in a straight line. If the person cannot walk in a straight line, or cannot walk at all, it’s time to make a quick descent so they can seek medical treatment.

Once the person is in the care of a doctor, the doctor will listen to the lungs with a stethoscope to check for any fluid buildup. In some cases, a chest X-ray may be requested.


The best way to cure any of the symptoms of acute mountain sickness is to descend as quickly as possible. Ascending any higher will only make the symptoms worse. The best time to descend to a lower altitude is at the first signs of acute mountain sickness. The earlier this illness is detected, the easier it is to treat.

For mild and moderate acute mountain sickness, the following treatments can help to ease the symptoms:

  • Ibuprofen – Can help headaches dissipate.
  • Diamox – This medication can help ease both mild and moderate symptoms. It will help increase respiration, which will increase oxygen intake, thereby reducing symptoms caused by lack of oxygen. Like any medication, Diamox can cause side effects such as tingling of the lips and finger tips, blurred vision and altered taste. It can also cause an allergic reaction in those who have not taken it before.
  • Extra oxygen – This can also reduce the symptoms caused by lack of oxygen.

For severe acute mountain sickness, these treatments may be needed:

  • Dexamethasone – This medication can help decrease any swelling in the brain.
  • Extra oxygen – This can also treat patients who have fluid in their lungs.
  • Nifedipine – This medication will lower blood pressure.
  • Breathing machines – They may be used if the patient is having difficulty breathing.


There are quite a few precautions that hikers and climbers can take when ascending a mountain.

For instance, many mountain climbers now take a portable hyperbaric chamber, known as a Gamow Bag, with them when they climb. The Gamow Bag is inflatable and big enough to fit a person inside. So if a climber begins to feel ill and need to acclimatize, they can get inside the bag, which creates its own atmosphere that feels about 3,000 to 5,000 feet closer to the ground.

Climbers can also avoid acute mountain sickness by climbing gradually, taking frequent breaks and sleeping at a lower altitude when possible. Most importantly, climbers should familiarize themselves with the symptoms of acute mountain sickness. If they don’t know what to look for, their situation can easily change from thrilling to life-threatening.


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