Hem High Altitude and AMS

High Altitude and AMS

Already at 2500 meters, you will most likely feel the effect of the thinner air. Exactly how this is going to ”hit” you is virtually impossible to know in advance if you have not previously been up at high altitude. Maybe you will be overtaken by large smoking old men going up the mountain, or maybe you yourself will pass even the most fit person.

Mountain Sick on Mount Kenya
Mountain Sick on Mount Kenya
At 2500 – 3500 meters above sea level is also where the risk of altitude sickness (Acute Mountain Sickness-AMS) begins to rise. My experience and lessons learned from guides, doctors and other climbers is that this risk can be minimized or, at best, to completely be avoided if you are careful to follow certain rules.


It’s all about acclimatization – it is about getting your body to “like” being at high altitude.

Go slowly uphill!
Make sure not to gain more than about 300-500 meters height per day. You can of course walk significantly higher in a single day — just make sure not to sleep at more than 300 – 500 meters above the level of the previous night.
Days of Acclimatization!
Stop approximately every 1 000 meters of altitude and rest for a day. This gives your body a chance to acclimatize.
Drink plenty!
The dry air of the high altitude drains you of fluid and you need to replace this. Try to get 3 to 6 liters of ”extra” every day. The dry air also means that the ”natural” thirst is limited – so drink although you’re not thirsty! Also it’s is believed that drinking a lot helps the acclimatization process per se – but that is under debate 
Travel in company!
If, against all odds, you are stricken, you will have invaluable help of not being alone. I have come across several altitude sickness cases and I dare say, that some would have gone south had it not been for the help of travel companions.
Remember your breathing!
A tip I got from a doctor in Nepal was to actively think of your breathing. His experience was that, if one breathed deeply and regularly, this could, to a large extent, minimize the risk of being affected.

It is no wonder that the body freaks out at high altitudes – the oxygen level diminishes disquietingly the higher you get, and you if reach the Earth’s top is down to a modest 33%.

M a s l Oxygen content
Extreme altitude (Zone 4)
Above 7 000
8 850 33 %
Very high altitude (Zone 3)
5 500 – 7 000
7 000 40 %
High altitude (Zone 2)
3 500 – 5 500
5 500
3 500
50 %
68 %
Pretty high altitude (Zone 1)
2 500 – 3 500
2 500 78 %
Sea level (Zone 0)
0 – 2 500
0 100 %

Why altitude sickness?

Altitude sickness is a result of, among other things, the reduced air pressure that impedes the body’s ability to absorb oxygen from the air, this in combination with the fact that the atmospheric oxygen content decreases (the proportion of oxygen, however, is all the time constant) when you go higher. This, in turn leads to a shortage of oxygen supply to the body. This in turn leads to moisture leakage (from the blood to the tissues) which in turn (again) affects the blood volume (which reduces) and blood concentration (which increases). A deep and good breathing brings more oxygen than a short and superficial.

Fluid losses incurred, mainly due to breathing in cold and dry air which your body heats and adds moisture to. Hence to breathe is simply to remove fluid – plenty of fluids from your system every day. At really high altitudes (4 – 5 000 meters and above) you might lose as much as 6-7 liters per day.

Symptoms and consequences

If you take it easy and follow the above advice is the risk small(er). But you should still pay attention to any symptom and what consequences a possible altitude sickness would bring to the party – and act accordingly!

Having said that, it is almost impossible to know how you will be affected or suffer – but generally you can say that the risk is greater:
• the faster you climb
• If you have previously suffered from AMS
• the younger you are

Headaches, sleeping problems and poor appetite are usually the first symptoms of altitude sickness. However, most of us are struck by this at high altitudes and usually this does not implicate that ‘stuff ‘ will get worse. If these symptoms turn really bad – make sure to rest one more day at the same height, or go down until you feel better and stay down there for one night.

Many people are afflicted by someone called Cheyne-Stokes breathing. This is short, but recurrent apnoea. This is not dangerous but is of course slightly uncomfortable. It is also affects your sleeping quality which in turn adds to the feeling of fatigue/exhaustion.

More severe symptoms are severe headaches, balance and coordination problems. Nausea and vomiting are also symptoms that will try to tell you it’s time to go down. If you don’t, that increases the risk of being struck by one of those really unpleasant symptoms such as loss of consciousness, oedema in the face, hands and feet, seizures, retinal hemorrhage and visual disturbances. The very worst symptoms are cerebral and pulmonary edema (HACE – high altitude cerebral oedema – and HAPE — high altitude pulmonary oedema) and blood clots.

What do I do if I suffer from altitude sickness?

If you have the slightest suspicion that you are affected go down!

There’s a lot of ”medications” to take for altitude sickness. However, I recommend to do it the ”natural way” instead, i.e. lose altitude. Drugs that contain acetazolamide, Diamox, for example, stimulates the respiratory ability and do you good in that way. Acetaxolamid helps to maintain the levels of carbon dioxide in the blood. Else the concentration of carbon dioxide will decrease, since ventilation/respiration increases at high altitudes. If you, as I pointed out earlier, concentrate on your breathing you might not have to take any drugs. (However, Diamox also helps you when you are asleep.) Diamox can however have some side effects that you should be aware of – and if you are allergic to sulfa, you cannot use it at all.

Ibuprofen is considered the best substance against headache at high altitude – but none is as good as going down.