7 Rules to Help keep Acute Mountain Sickness at bay

One of the biggest challenges which make the completion of your trek uncertain is the possibility of being struck by Acute Mountain Sickness (AMS). I’ll start with a quick background on altitude sickness.

As one climbs above 8,000 feet, the atmospheric pressure starts to fall noticeably. With every breath you take, less oxygen reaches your blood.  Your body copes by breathing harder and longer. When you are climbing this case is acute. Persistent short breathing builds up carbon dioxide in the blood.

As you climb higher your body acclimatizes naturally to the decreasing oxygen levels. Your body builds up a ‘zone of tolerance’ – where it can function normally even with the decreased oxygen. This zone of tolerance moves up as your body acclimatizes to the higher altitudes. However, when the build-up of carbon dioxide is beyond your zone of tolerance the body reacts and you fall sick. This is high altitude sickness.

It is accompanied by symptoms of feeling lightheaded, nausea and an unbearable headache. Acute Mountain Sickness can escalate quickly which can be fatal if not treated in time.

I have been trekking in the Himalayas for close to three decades across my 50 years of living. Having done the basic mountaineering course from Himalayan Mountaineering Insititute and an emergency medicine course from Red Cross, I have listed some ways in which I’ve learnt to prevent high altitude sickness.

1.  The Fitness Paradox about Acute Mountain Sickness

Statistically,  it is observed that fitter trekkers are more likely to be affected by Acute Mountain Sickness. However, the bottom line is that physical fitness (cardio and muscle endurance) is critical to completing a trek while enjoying it.

There is actually a deep reasoning behind it. Fit trekkers think they can gain altitude much faster than what their body can humanly tolerate.

The general thumb rule is that you should not gain more than 1000 ft/day.

I have got a few more tips for you:

a. Gain an average of only 100 ft per hour: If on a given day, the route demands a gain of 1000 ft, the total time between the campsites should be about 10 hours including breaks along the way. Therefore it is mandatory to start early.

b. Take a 15 min break after gaining every 300 ft. The breaks should include deep breathing, hydration, as well as some high energy snacks such as dry fruits, energy bar, etc.

2. The Pee colour test

At higher altitudes, especially if the trek is on a cold and dry day, the body loses an enormous amount of water through perspiration which is not really visible. The cold temperatures, on the other hand, inhibit the sensation of thirst. The resultant dehydration can trigger symptoms of Acute Mountain Sickness. Therefore to prevent this, I came up with a very simple run-time test.

a. On the trek, continuously monitor the colour of your urine. If it is clear white to pale yellow, you are fine. If it starts to turn yellowish en-route, the body is getting dehydrated. Immediately start a cycle of hydration. Remember that gulping down litres of water in one go is not a good idea. Sip your water gradually and for a longer duration for it to absorb effectively.

b. The hydration cycle that works for me is having one glass of water every 15-20 minutes spread over 1.5 – 2 hours. I have found that without exception, this gets the body adequately hydrated and back to normal.

3. The Englishman diet

The body is stressed at very high levels on multiple fronts on a high altitude trek. It is not the best of times to stress it by incorrect food choices.  You should eat a proper breakfast, lunch, evening snack and dinner- in addition to energy bars/dry fruits along the way. Read this article for more food ideas.

Food should be low in fat, preferably bland and have easily digestible carbs.

Avoid using chilli – it improves the taste but induces artificial perspiration which is dehydrating. What you can use instead are spices. Use a slight bit of turmeric, asafoetida, and fennel seeds. Our modern Englishman has been influenced by Indian Ayurveda.


Trekkers cooking their own food on a trek. Picture By: Milind Tambe

4. A Big NO to Alcohol and Smoking

Alcohol and smoking have the potential to induce both Acute Mountain Sickness as well as hypothermia. They are both potentially fatal on a high-altitude trek. Check out this video below to learn why we ask trekkers to refrain from such choices.

5. Mineral Balance

Trekking is a strenuous activity that goes on for multiple days. Medical reports suggest a significant change in mineral levels in the body during an extended high altitude trek, which could trigger Acute Mountain Sickness.

My tasty solution has been to consume ORS every day. I have always carried Electral powder with me and I drink 1 litre of water spruced with Electral every day.

6. The Golden Pace Rule

Every person has a natural rhythm and pace in their walk. I call this the golden pace. This is normally independent of their athletic ability. I have friends who are marathon runners but when it comes to walking have a golden pace of mere 5 km per hour. They can certainly walk faster as they are fit. However, any walking pace faster than the golden pace would tire the person out quickly. A tired body is vulnerable to altitude sickness.

Trekkers marching their way up in snow Picture By: Reyan Hazra

Therefore, I have found that trekking at the golden pace is better than competing with fellow trekkers. My wife is not an athlete. But she has done Roopkund and Kuari Pass without any issues. It is because she walks at her golden pace which is much different than my pace.

If you walk at the golden pace, there should be no breathlessness or feeling of exhaustion and only mild sweating. You need to change your pace if you feel tired or exhausted.

Climbing and trekking are supposed to be team-building sports. There are no individual prizes or victories. It is about the experience. Yet I have seen that trekkers very often get subconsciously psyched into meaningless races and timings.

7. Dry and then warm yourself at campsites

The Shea Goru campsite at Hampta Pass. PC: Venkatesh Allu.

Immediately after reaching the campsite, it is important to change from your sweaty clothes (including undergarments) into dry clothes. Sweaty clothes in cold campsites lead to hypothermia conditions or an upset stomach due to indigestion. Layer appropriately according to the temperature and wind conditions. This is among the first things to do and certainly before the well-deserved break.

I have observed trekkers catch a serious respiratory infection which is not good in a situation of reduced atmospheric oxygen. My general rule has been to set up the tent, change, and then do anything else. One should perform deep breathing exercises before going to sleep. It helps in boosting the oxygen saturation.

These are the rules I follow to keep Acute Mountain Sickness at bay. I hope you’ll find them useful for your next trek! If you think I have missed out on any point, do share in the comments below.

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11 thoughts on “7 Rules to Help keep Acute Mountain Sickness at bay

  1. Absolutely agree about the fact that trekking is a lonely sport and that trekkers should refrain from treating it like a ‘running race’. Trekkers need to find the pace that THEY are comfortable with and not look at others to decide how fast they should be moving. I don’t see any point being on the mountains if one doesn’t stop to admire the view that is on offer. People should go to the mountains not to ‘compete’, but to get away from competition.

  2. Wow……
    Very well written and all these things should be followed by every trekker :).

    I like the lines “……There are no prizes or victories. It is about the experience.”…..and yes many times I have seen a meaningless “Rat Race” between trekkers….to reach next campsite first rather then experience and enjoy the nature .

    Almost every thing fine including personal tricks …..

    I would be more better if you include an important part of every organised trek, even for many not less then a phobia , i.e. “Consumption of Dimox”.
    Very few trekkers know about its working, possible side effects and precautions while taking it.

    Even it creates confusion many times …..”all are on Dimox medication …what will happen with me if I would not take it”

    1. The working, possible side effects and precautions while taking Diamox are all published adequately and further advise can be sought from a general physician.

      Diamox (and its equivalents) work in two ways:
      1. As a preventive: Here it is taken regularly from the start of the trek (at low altitude) in low doses. As a preventive, Diamox reduces the chances of AMS, all other things remaining the same.

      2. As a curative: While there is no real cure for AMS except loosing altitude, Diamox as a curative is taken at almost double the preventive dose, once AMS has set. Here it slows the progress of AMS, giving the trekker adequate window to make a safe descend.

      First and foremost: ALWAYS carry Diamox (or equivalent) with you, because you never know when you or someone with you may need it as a curative.

      The real question is, should Diamox be used as a preventive.
      1. If completing a set trail is of paramount importance, then the preventive course should be taken.
      2. If one believes that trekking is not just a path between a pre-decided start and finish, then whenever the trekker is feeling ill, or the weather is turning in, there is always the option to turn back (or camp additional days if soloing like me). In such situations, Diamox as a preventive is not needed. Life is long, and one can always come back.
      3. If the highest point of the trail goes above 17000 ft, then also a preventive course may be needed. However, very few trek routes touch this altitude, as it gets technical.

      Frankly, I do not think that there exists a correct answer to the question if Diamox should be taken as a preventive. It depends on the trekker. Most trek organizers recommend Diamox as a preventive, as many trekkers view a trek as being successful only if they reached the intended destination campsite – hook or crook.

  3. Well written article! There’s another point I wish to add, using the right pair of sun glasses are crucial to prevent snow blindness which can sensitize one to AMS. You’ve rightly pointed out to diet as a factor! It’s important to eat well on the trek especially the early days to provide energy reserves that would be crucial in preventing AMS during summit attempts!

  4. Very useful tips, although on organised treks by India Hikes, the altitude gain tip can’t be followed, since there are often days with over 3,000 feet gain at lower altitudes…I guess they plan it keeping in mind that such gain is ok at a lower altitude (6,000-10,000 feet) but this is the part that always worries me..
    Additional point I don’t like to make as someone whose golden pace is a little slower: it might get difficult on an organised trek to maintain your golden pace if you are being pushed to go faster all the time cause you’re at the end, but I’m not one to walk at any pace that isn’t comfortable to me, so I just compensate by starting a little earlier than the group, so that I don’t slow them down..

  5. It’s a good and essential read and to remember the same…..
    and to follow instruction and watch out for the untoward

  6. Yes , I had a bout of AMS . I faced it . It is very dangerous . It makes a treker absolutely a nothing . I lost every sense of my surroundings . A voidness , a hollowness took control of me . Strange part is that It happened while descending a slope . In Beluni top . It was for an hour or two that I passed thru it . As soon as I descended a considerable height to Kanthalia and in safe place , it was gone . I was fit . It may be that my anxiety due to the white out along with a drizzling triggered it . We lost our way also .
    This is good writing by the good Doctor and every mountaingoer should make it golden rule . Please remember , a mistake in the mountain will not be pardoned .

  7. Please change the font.
    All ‘e’s are looking like ‘c’s and its difficult to read.

    Is a tingling sensation in the tongue a sign of AMS?

  8. I have found this information on Acute Mountain Sickness very useful and would like to appreciate the writer. I will also refer one website here which has been created for a social cause to educate the people complete information about Acute Mountain Sickness