How to Prevent AMS (Acute Mountain Sickness)

Acute Mountain Sickness (AMS) or altitude sickness is a condition that can be easily prevented or cured and yet many people die from it just because of lack of information. Therefore, it is very important to know about it. Especially, if you are an adventure lover planning to go trekking or skiing. If you or anyone you know will be travelling to altitude above 2400m, tell them what AMS is and how to prevent AMS.

What is Acute Mountain Sickness (AMS)?

Doctors believe that AMS is our bodies’ response to the lower air pressure and lower level of oxygen at higher altitude. It is marked by a slight headache along with at least one of other symptoms- nausea, loss of appetite, lethargy, vomiting, shortness of breath even when resting and/or increased heart rate. Anyone travelling above 2400m are susceptible to AMS. However, it is not sure who are more susceptible. A healthy and fit person may succumb to altitude sickness while a less healthy partner may be fine. Therefore, when you recognize the signs of AMS, you should not try to ‘get over’ or ‘brave’ it and should try to prevent further development by taking proper measures. If neglected, AMS can develop into more fatal forms like High Altitude Pulmonary Edema (HAPE) and High Altitude Cerebral Edema (HACE).

How to prevent AMS or Altitude Sickness

So, how can we prevent AMS? We can take following measures.

Ascend Gradually

The severity of AMS is proportional to altitude gained and the speed of climb. The higher we go, thinner the air is. The amount of oxygen in the air is same in percentage but we take in lesser oxygen particles. This causes AMS and we can prevent it by gradually becoming used to that condition. We call it acclimatizing. Acclimatization is the process in which an individual organism adjusts to a gradual change in its environment. Therefore, we should climb slowly. High altitude trekking itineraries have acclimatization days to prevent AMS. It means to spend a day (two nights) at a place every few hundred meters higher.   It is suggested to take an acclimatization day at an ‘intermediate’ elevation below 3,000m and after every 300-500m altitude gain above 3,000m.

Climb High Sleep Low

‘Climb High, Sleep Low’ is another approach to acclimatizing.  This exercise helps our body adjust to the low level of oxygen.


Keep Yourself Hydrated

We should drink a lot of water before starting the climb and drink a lot during. The goal is to stay hydrated because dehydration thickens blood which means it circulates slower which, in turn, means that oxygen is not being properly transferred to all parts of our body. This is when we are already taking in lesser oxygen. Therefore, dehydration makes us weaker against altitude sickness. Hydration, on the other hand, makes the blood more mobile and keeps us active. Over hydration, however, has no benefit.

Eat Properly

It is necessary to stay healthy and nourished. Eat well. Studies have shown that foods high in carbohydrate alleviates AMS symptoms. Thus potato, rice, breads, pastas, fruits etc. are good for travelling to higher altitude. This probably has something to do with the relation of sugar level in blood and oxygen. Thus, eat high carbohydrate diets during acclimatization.

What to Avoid

There are certain things we must avoid to prevent AMS like alcohol and too much salt. Both alcohol and intake of too much salt cause dehydration. Remember that it is important to stay hydrated. We lose a lot of moisture through trekking alone. So substances like alcohol and salt should be avoided. Sleeping pills should also be avoided as they are respiratory depressants (alcohol too) and can slow the process of acclimatization.


Acetazolamide (Diamox) is the popular drug known to prevent AMS. Other herbal remedies like chewing on coca leaves or root tissue of Radix Rhodiola did not prove effective in clinical study. Do not depend on them to work. Take Diamox instead.

These are some ways to prevent altitude sickness. Prevention is always better than care. However, if you do start to feel the effect of AMS, do not take it lightly. Immediately stop climbing higher. Descending rapidly (but carefully) helps. Also, some people take longer to acclimatize so do not rush it. Take extra rest day if required.

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