This section is only an aid to summarize the key elements related to high altitude trekking. It is essential to consult your doctor for precautions and measures regarding acute mountain sickness, each case being different.

The main danger trekkers in high altitude usually face is acute mountain sickness (AMS) and its complications. In fact, 15% of hikers feel its effects after 2000m above sea level and around 60% will be affected from 4000m and up.

It is important to know that age is not a factor: AMS affects both young and old people, and that physical fitness does not prevent its occurrence. All can be affected. And as gaining altitude slowly and gradually is vital to avoid AMS’s symptoms, young athletic people are often victim of their overconfidence.

Fortunately, there are several precautions to take before and during the trek to avoid this high altitude induced syndrome that can escalate very quickly.

Basic rules to avoid AMS:

  • Gain altitude slowly. It is recommended to at least take a one day break to acclimatize at 3000m, and then one for every 400-500m elevation gain.
  • Drink a lot of water. A lot, I couldn’t stress this enough.
  • Maximize your acclimatization days. One way to make the most of these rest days is to gain some altitude during the day only to come back down and sleep at a lower elevation (ex.: get on top of a small summit/hill or go hiking around for a few hours).
  • Take medication prescribed by your doctor to prevent AMS or to reduce its symptoms (ex.: Diamox).
  • Stop gaining altitude when the first symptoms appear (and go back down if they get worse or don’t diminish in the next 24 hours).

Still, even if you have been extremely cautious, you might be affected by AMS at one time or another during a trek in high altitude. It is then extremely important to know how to recognize the symptoms, to communicate them quickly and to stop the climb.

The first symptoms of AMS:

  • General fatigue
  • Headache
  • Dizziness/vertigo
  • Loss of appetite and/or nausea
  • Difficulty to sleep
  • Confusion

Again, this page is only an aid to simplify the understanding of the measures to be taken when hiking at high altitude and to facilitate the preparation of such a trek. Consulting your doctor is necessary.