Even if you have followed all recommendations, you can still altitude sickness to get. Some people are very sensitive to that. In this article we will discuss the symptoms and measures that you can take against it. Acute altitude sickness (Acute Mountain Sickness or AMS) is possible (certainly not) due to fluid retention by the body and the discharge of fluid from the blood vessels caused by oxygen deficiency. This sounds rather dramatic, but in the small extent to which it usually occurs, you notice little or nothing of it. But that doesn't always apply. Acute altitude sickness is common above 2500 meters. Between 2000 and 2500 meters you sometimes see mild forms of acute altitude sickness, but almost never severe forms.
As you rise faster and sleep higher, the risk of complaints increases and these percentages rise. About 25-50% of all people who rise above 2500 meters. Gets light or severe forms of acute altitude sickness within 12 hours of reaching this altitude.
Top 10 complaints with acute altitude sickness
Below is an overview of complaints that were common in a group of 147 tractors in the Himalayas, where heights of 2500 to around 5000 meters were reached.
1. Headache - 96%
2. Insomnia - 70%
3. Lack of appetite - 38%
4. Nausea - 35%
5. Dizziness - 27%
6. Headache that does not respond to painkillers - 26%
7. Severe fatigue - 25%
8. Less urine excretion - 19%
9. Vomiting - 14%
10. Slowness - 13%
The most common complaint about (usually mild) altitude sickness is headache. During a well-organized trip, a good guide will often ask you if it is bothering you. Slight headache that only occurs during the day and responds well to painkillers is not very important. Even if the headache does not respond (sufficiently) to painkillers and you have no further symptoms or symptoms, that is difficult but not disturbing. It is better not to continue climbing with it immediately; often the pain will go away after one or two days at a height and then continued climbing is not a problem. If the headache does not disappear with rest, further climbing is dangerous. Sometimes severe headache is also accompanied by 'hypersensitivity' to light and complaints about being able to see less clearly. Since it takes a few hours after a climb before the first symptoms occur, we often see that these occur during the night. Headache that starts at night and / or in the early morning is the worst and does not respond to painkillers, you should therefore take it seriously: this almost always indicates incipient altitude sickness. Incidentally, this calls for planning a trip in such a way that you arrive at your destination early in the afternoon, so that you can still descend by light when serious complaints arise. No headache while climbing is considered a sign of good height adjustment, but it is not proof that you do not have altitude sickness or that you still cannot get it.
Sleeping problems are also high on the complaints list. Many people notice that they sometimes have crazy and / or vivid dreams. The cause is not known, but it certainly does not awaken you. This is the case with people who suffer more than average from the irregular and less frequent breathing at night at altitude. This is because the brain centers that control breathing become less sensitive and therefore respond to a need for oxygen later than normal. The already lower oxygen concentration in your blood then drops even more. You then wake up more often because the oxygen supply to your brain is not optimally uniform. Sometimes you see yourself as a shock to your sleeping companion a very irregular breathing and it seems that he / she does not breathe for quite a long time and then suddenly wakes up short of breath. However, this is (in this case) quite harmless and requires no specific attention.
A reduced appetite also occurs in many people. Make sure you eat enough, because your body needs a lot of extra energy because of the physical efforts you have to make. Many climbers come home with kilos lighter than they left.
A slight nausea is the following, also regularly observed phenomenon. This may be caused by your body trying to send more blood and therefore oxygen to the vital organs (heart, lungs, brain), which is at the expense of the blood supply to the stomach and intestines. Sometimes the nausea is accompanied by vomiting. In that case you have to drink extra much to compensate for the loss of moisture.
More than normal fatigue with a certain amount of exercise is seen quite often. This in itself is not a cause for concern, but in certain cases it may be a signal that there is (starting) pulmonary edema and then there is indeed a life-threatening situation. In some cases, despite acute loss of height, despite the loss of fluid, fluid retention can be seen in the legs and arms and in the face. That moisture is there, but not 'usable' for your body.
A light feeling in the head and sometimes a little dizziness are less common, but also indicate possible altitude sickness. The brain is very sensitive to oxygen deficiency. The brain function is therefore relatively often less optimal. The calculation and, for example, the repetition of long and complicated sentences are no longer without mistakes. Usually you don't even notice that yourself, only at a very high altitude (6000m) can it sometimes get so bad that it stands out. If this remains the case, this is not a problem. After descent, the brain function fully recovers
Some people think that diarrhea is also an expression of altitude sickness. That is not the case. Unfortunately, diarrhea increases the risk of altitude sickness or exacerbates an existing altitude sickness because you lose a lot of fluid. If you have diarrhea, then you have to drink even more than you already did.
Author: Han Willems - More info about altitude sickness