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How to Prevent and Treat Altitude Sickness

altitude sickness

A few years ago I took the Salkantay trek to Machu Picchu in Peru. The trek lasts five days and covers mountainous terrain, especially in the early going.

Still not fully acclimatized, I made the mistake of hiking too fast on the first day. When we reached the camp (altitude of 4000m or so), I had a headache, my heart was pounding, and I was lightheaded and dizzy. I decided to pass on dinner and retired to my tent early. I couldn’t fall asleep though, a combination of the cold and my pounding head. I shivered for hours, listening to the wind whip around the Salkantay glacier. I resigned myself to a sleepless night.

Sometime after 3AM I violently shat my pants inside of my sleeping bag, one of the biggest catastrophes I’ve ever had to deal with in my life. But that is a story for another time. Today, I’m going to tell you about altitude sickness and what you can do about it. Altitude sickness may not have directly caused my intestinal ailment, but I don’t doubt that it contributed to it.

The Symptoms

Altitude sickness, also known as acute mountain sickness (AMS), gets cranking once you get 8,000 feet above sea level. Principle symptoms include: headaches, dizziness, and cramps. As it gets worse, altitude sickness can also cause vomiting and dehydration. If things get really bad, confusion, coughing fits and full on dementia are possible.

In severe instances, altitude sickness can lead to death. High altitude pulmonary oedema (HAPE), which involves fluid buildup in the lungs, and high altitude cerebral oedema (HACE), which involves fluid buildup in the brain, can both be fatal. HAPE produces breathlessness, even when at rest. An elevated heart rate and body temperature are also common symptoms. It’s also possible for someone suffering from HAPE to have a cough producing pink or white frothy sputum.

HACE progresses quickly and usually involves symptoms of confusion, drowsiness, vomiting and lethargy. If you are worried that someone has HACE, a good test is to have them walk in a straight line. If they struggle to walk heel to toe in a straight line, they may be suffering from HACE.

Both HAPE and HACE can lead to death. HACE, in particular, can cause death within a matter of hours. While it is not known exactly what causes either condition, it is widely accepted that ascending too quickly is a major factor. It is also thought that HACE or HAPE can occur when a person with severe altitude sickness decides to press on, rather then descend or rest. More information on HAPE and HACE here.

It would be wise to try and prevent altitude sickness from occurring, but if it does, make sure you take steps to treat it instead of exerting yourself further.


Rest at altitude before getting active – If possible, avoid strenuous activity for 24 hours.

Stay hydrated – Dehydration can be exacerbated by altitude sickness. Drink lots of fluids.

Ascend slowly – Many hikers will climb high, but sleep at a lower elevation, and then repeat the process the next day. This helps your body acclimatize.

Medicate – Some drugs, such as acetazolamide, are used for preventing the onset of altitude sickness. For most people, however, this is not necessary. Consult a doctor if you have reason to believe that you are especially susceptible to altitude sickness.


Descend! – The simplest treatment option. You will be surprised how quickly a descent can begin to make you feel better.

Oxygen – Altitude sickness is largely caused by lack of oxygen, and supplemental oxygen can be used to relieve symptoms.

Coca leaves – A treatment used by many indigenous people, chewing coca leaves can also relieve the symptoms of altitude sickness.

Medical attention – If things are really bad (confusion or dementia, for instance) you need to get medical attention immediately.

The Golden Rules

1. If you feel unwell, you have altitude sickness until proven otherwise
2. Do not ascend further if you have symptoms of altitude sickness
3. If you are getting worse then descend immediately

– From Dr. David Shlim

Have you had altitude sickness before? Tell us about it in the comments.

Photo credit: ilkerender

{ 5 comments… add one }

  • ayngelina March 23, 2011, 9:25 pm

    I worked in Cusco for a few weeks and the worst cases often came from people who flew in from another country and did not have time to naturally acclimatize to the altitude.

    I was amazed at how quickly people started feeling better when they chewed (vs. drinking tea) the coca leaves.

    I highly recommend it.

    • admin March 24, 2011, 12:13 am

      Hey Ayngelina,
      Thanks for stopping by 🙂 Yeah, I took it easy when I arrived in Cusco. Coca leaves were a big help for me also. I refused the first couple times they were offered, but by day two of the trek I was practically begging for them. – Phil

  • Sandi April 14, 2011, 2:13 pm

    I arrive to Lim and want to fly into Cusco same day the 26th, I’m wondering is it a good idea to go to cusco and straight to aguas caliente>? that way i avoid the higher levels? i’m really scared of getting sick or dying that i’m thinking of cancelling Peru all together! HELP

    • admin April 14, 2011, 2:36 pm

      Hi Sandi,
      I think you will be fine. When you arrive in Aguas Caliente, just take it easy and rest for a day. Same thing if you go back to Cusco from Aquas Caliente, take a rest day. You don’t need to worry about dying, and if you do feel sick just slow down, drink lots of water, and rest.

  • Mei January 18, 2016, 3:13 pm

    But somebody say if a person descend too fast, it is not good neither. Most people climb Mt. Everest die on the way of descend, not ascend. Is it true, and why?

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