High altitude sickness can happen to anybody regardless of age and physical condition. In this post, I provide some facts and advice on how to deal with it.
In summer 2014, I performed a simple experiment in mountains. I was at a peak a bit above 3000 meters and had an empty plastic juice bottle with me. It was intact, I opened it and then closed firmly. That was all I did.
Later in Belgium (at just a few tens of meters above the sea level), I took the bottle from my rucksack, and it was in the shape which you may see on this picture.
So what happened with the bottle?
When I closed it at 3000 meters, the pressure from outside was the same as the pressure inside, the bottle was intact. When I went home, nearly at sea level, the outside pressure was by almost 30 percent higher.
So the necessity for the balance of pressures outside and inside caused the shape of the bottle as it is on the picture. The balance was established and the bottle became crushed.
Why was this happening?
Do you still remember from school the famous experiment with Magdeburg hemispheres? In short, two empty hemispheres were just put together, the air was pumped out, so there 
was a vacuum inside and only the atmospheric pressure kept them together. But they were so well-kept that several teams of horses, pulling in opposite direction, were not able to split them away. That is the power of pressure.
Now back to my bottle. The pressure with altitude changes by following the well-known barometric formula. It decreases exponentially. So when I closed the bottle at the mountain top, I fixed its inside pressure. As I was descending, the outside pressure was becoming higher, the body of the bottle could not resist it, and it was becoming more and more crashed, getting its final shape as seen in the picture.
Now imagine that I was going to the Dead Sea shore in Israel, which is 429 meters below the world sea level. The pressure there is around 790 mmHg, which is higher than the average 760 mmHg (this is called 1 atmosphere) at the world sea level. Obviously, the bottle would be far more crashed.
This demonstrates the effects of decreased air density with altitude. The air is a mixture of various molecules. The amount of oxygen in the air is about 21 percent, and this relative ratio remains nearly the same with altitude. This is why people have the problem with breathing at higher altitudes, and this may develop in what is known as acute mountain sickness (AMS).
Normally you do not feel this in an airplane because it is artificially pressurized to the level which is roughly similar to conditions on a mountain of around 2000-2500 meters. This is usually good enough because of minimal movement we perform on a board of a plane, but if you would start exercising you would feel the difference immediately.
More serious levels of altitude sickness are known as high altitude cerebral edema (HACE), and high-altitude pulmonary edema (HAPE).
HACE is the excess of fluid in the brain, resulting in confusion, laziness, and emotional behavior. It can be fatal. I have read that about 1% of people ascending above 3000 meters get HACE, and it can develop even at around 2100 m, such cases have been reported. In general, the faster you go up, the more likely it is that HACE will happen.
HAPE is a build-up of fluid in the lungs that prevents the air spaces from opening up and filling with fresh air with each breath. This can be fatal within hours. HAPE usually develops after 2 or 3 days at altitudes above 2500 m. People suffering from HAPE are breathless, they cough and this is accompanied by a pink frothy sputum, heart rate is faster, the lips are blue, the temperature is high.
There is no clear formula which would determine at which altitude the sickness happens, or how to avoid it. Typically, in the literature, you may see that symptoms may develop above 2400 meters. I myself have been above 4000 meters and did not have any particular problems except for slight dizziness. However, already above 2000 meters, I can feel some slight difference, as if something is missing when I breathe, and this sometimes accompanied by slight heart arrhythmia.
So in general, the symptoms are totally individual, and they may appear with anybody, regardless if you are a trained sportsman or not. Fitness or gender plays no role at all.
The most common symptoms of AMS are:
- Headache
- Lack of need to eat
- Vomiting
- Lethargy
- General weakness
- Dizziness.
In more serious cases lungs and brain are affected, the sick person cannot walk, the lips are gray, heavy breath.
What to do in the case of AMS?
Here one simple sentence only: descending immediately, there is no alternative.
How to avoid altitude sickness?
Give your body time to acclimatize and gain altitude slowly if you are on a several-day trek, like climbing Kilimanjaro. It may take weeks to acclimatize if you go really high. The golden rule is well known, climb high and sleep low. It is recommended that above 3000 m you should do no more than 300 m per day, and this in such a way that you rest one day every third day.
But I do not believe many people obey such rules. For typical altitudes in the Alps, you may speak about one week of proper acclimatization.
Here are a few data showing the change of oxygen with altitude:
- 2000 meters – 80 percents (%)
- 3000 m – 71 %
- 4000 m – 63 %
- 5000 m – 55 %
- 6000 m – 49 %
- 7000 – 43 %
- 8800 -33 %.
Just to put this into a perspective, here are some mountains so you may see how much oxygen you may expect once you climb them: Lagginhorn is 4010 m, Mont Blanc is 4807 m, Kilimanjaro is 5895 m, Mount McKinley 6,194 m, Aconcagua (6962m), Mount Everest 8.850 m.
Knowing these facts, one can only be astonished by what R. Messner has achieved by climbing all 8000-ers without oxygen. This man has obviously moved boundaries of human capabilities.
When I was climbing Mount Fuji in Japan, I have seen some elderly people using Teide, which is here at hand on Tenerife island.
I would conclude this review by saying that it is quite normal to feel tired when you are close to 3000 meters in the Alps, every step you make there is heavy. It may also be normal to feel some slight dizziness in such an environment, in my case sometimes this is partly due to the fact that I do night climbing, and I am simply tired.
But if you feel more than these symptoms, then it is best that you descend. The situation can hardly improve if you stay at the same altitude.
I shall be happy to read your comments on this text.
shelby says
Hey there! I found your picture and description of the water bottle to be very helpful in understanding altitude pressure, and why so many people suffer from altitude sickness. I have had altitude sickness on several occasions; although usually not bad enough to stop me from whatever I was doing. The personal oxygen tank is a great idea!
Jovo says
Thank you Shelby, great to hear from you. This sickness is indeed unpredictable. I climbed Teide 5 times with just normal symptoms, but in my 6th climb I hardly managed. I used to go to much higher altitudes elsewhere without issues. So you never know how the body will react. Those oxygen bottles I saw first time on Mount Fuji, some elderly people were using them. Obviously useful.
Boniface says
Hi Jovo
Great post that one is. It is educative too. I have never never had the opportunity to climb any high mountain despite being near two high ones- Mt Kenya and Mt Kilimanjaro. I hope to one day at least climb Mt Kenya like one of my old friends.
I like the information you’ve given on acclimatization. Surely that seems like the real backbone of the process of mountain climbing that that can that can never that can never be ignored.
Again, thanks a lot!
Jovo says
Hi Boniface, one of dreams is to climb Kili. Not sure if this will ever happen, but I want this since the moment I saw its picture. Yes, for these two mountains you definitely need acclimatization. Good luck if you ever go, and let me know…
Tyler says
The fact that you’re an experienced climber makes your website that much better! People are much more likely to listen and read from someone with experience. Great setup and niche selection.
With the personal oxygen supply, would this be recommended for those first starting off in climbing as a necessity than gradually work away from it as we become more experienced? I’m thinking the body will become more conditioned over time.
Thanks for sharing!
Jovo says
Hy Tyler. Thank you for the comment. You do not need to think about the altitude sickness too much in advance. You will see how your body react, this is very individual and unpredictable, it does not depend on your physical condition. This is just the matter of acclimatization. Some people need more time, some less, no rule at all. I have never used personal oxygen supply for typical altitudes in the Alps.
Don says
Hi Jovo,
It is very common that people suffer from this as it is a difference if you are at 1,000 meters or 5,000 meters. I have also some friends who love climbing the mountains and told me about that. That’s why I was so interested in you explanation and it’s really interesting.
I think the better people are trained for this the better it is and the less problems they have.
Cheers
Don
Jovo says
Thank you Don, great to read your comment. Yes symptoms of high altitude sickness are always present, and this is very individual and hard to predict. Acclimatization is the only way to cope with this.
Kush1000 says
Hey! Great post you have created here. Interesting stuff with plastic bottle, I will definitely try this when I climb to a mountain. People forget how beautiful mountains are.
I’m sure many people will find this article useful and interesting as I did.
Thanks for sharing this and have a great day!
Cheers and good luck
Jovo says
Many thanks Kush, great that you like my text. I hope it has been useful. Best luck.
renan says
Hi Jovo,
I know you can have complications when climbing a mountain but here you affirm and demonstrate how a climber could have more serious difficulties than one can imagine. Thank you very much very illustrative and reliable information to consider and prepare well before you start to climb.
renan
Jovo says
Hi Renan, thank you for the comment. High altitude sickness is something one must count on, not possible to predict regardless how fit one is physically.
Gary says
You have written a very interesting article. I noticed some altitude effects when I moved from Phoenix Az (330 meters) to Flagstaff Az (2150 meters). Normally I didn’t notice it at all, but if I had to work in the yard or walk up a steep grade in the mountains I certainly noticed it a lot.
I’ve read some articles about the Tibetan people who live quite comfortably above 4000 meters. It was thought that they adapted to that altitude over time. It turns out there is more to that story.
40,000 years ago there were three human races that we know of, the modern human (us), the Neanderthal, and the Denisovan. Two have gone extinct but not before cross breeding and giving the ancestors of the Tibetan people a unique gene that aids them at high altitudes. Only a few percent of the Han Chinese in the lowlands have this particular gene.
It’s funny that when the Chinese government took over Tibet they moved many Han to the mountain for political reasons. Very few of them can function at that altitude which is a continuing problem for the government.
Gary
Jovo says
Thank you Gary for such a great comment. I have learned new things from what you write here. I have read some recent stories about Denisovans and where their genes were spread. It is fascinating to read about this. Thank you again.
Chris says
Funnily enough my uncle was on about something like this about a month back – he’s an avid mountain walker in south Wales ( where I live ). He believes there is a connection between smoking and this sort of sickness – since he went on the e-cigs he feels altitude is not a problem any longer ( he also advised drinking lots of fluid ). What are your views on this?
Jovo says
Hi Chris, thank you for the comment. I guess quitting smoking is good in any case. Drinking liquids is surely advised at high altitude. So I would say your uncle is doing it right.
Claire says
Hi Jovo – I read this piece with interest. As a skier, I feel the effects of high altitude at around 2700M – it’s hard work on your body exercising at that level. You’re right when you say it affects others differently, as none of my group complain until we get a bit higher, but I am considerably smaller than the guys I ride with, so I guess that’s why.
I tweeted this for you 🙂
Claire
Jovo says
Hi Claire, thanks for the comment. It does not matter if you are smaller, it is completely individual how the body reacts. Cannot be predicted. Jovo
Lynn says
Oh I remember when I first had altitude sickness. WOW it took me by surprise and I wasn’t really sure what it was. Great website!
Jovo says
I always feel slight symptoms above 3500 m, but never anything serious. This is completely individual, and can affect anybody. Jovo