As the altitude increases, the air becomes thinner; from about 2, 500 meters threatens the altitude sickness. Even at an altitude of 3, 000 meters, you have 40 percent less oxygen to breathe. Headache, loss of appetite, nausea, vomiting, tiredness, shortness of breath and dizziness are among the first signs of altitude sickness. The most important rule is: rise slowly. Every year, half a million high-altitude tourists visit the Himalayas, the Andes, Elbrus in Kauskasus or Mount Kilimanjaro.
The altitude sickness
As sublime as you can feel at altitude, extreme mountaineering also has its downsides: "On every tenth 'summit winner' comes a dead man, " writes Reinhold Messner about tourism on Mount Everest in Explorer Magazine.
"At the top, not only does our judgment, and ultimately the overview, vanish. Willfulness, bloodlessness and apathy slow the mind down in the death zone." "Controlling our breathing is not designed for extreme heights, " says Klaus Mees, a Munich professor at the Department of Otolaryngology at Klinikum Grosshadern. He must know because Mees has been exploring altitude sickness over 7, 000m several times in the death zone of Mount Everest - a suffering that costs more climbers their lives than rockfalls, storms and avalanches combined.
Symptoms of altitude sickness
The altitude sickness has many facets. Even when climbing high mountains from about 2, 000 m, the first signs can appear.
The main symptoms of altitude sickness are:
- a headache
- loss of appetite
- difficulty in breathing
- difficulty sleeping
- reduced water and salt excretion.
Tourists who travel from the lowlands into the mountains and go on big tours on the first day often complain about it. If these symptoms do not disappear after some time and breaks, you should turn back, because the higher you go, the worse the discomfort will be.
The cause of the complaints
As the altitude increases, the air pressure decreases, and so does the partial pressure of oxygen (that is, the proportionate oxygen pressure). At 5, 500 m, the oxygen partial pressure has already been reduced by 50 percent and at 8, 000 m it is only about 35 percent. Up to the highest peak on earth, Mount Everest (8, 850 m), the air pressure drops by two-thirds. As a result, the lungs absorb less oxygen and an oxygen deficiency, known as hypotoxia, occurs.
The result: Above 7, 000 m, around 80%, at Everest height, almost 100% of people become unconscious within 2 to 3 minutes and die shortly thereafter, when they do not receive additional oxygen.
The body's own breathing control is mainly based on the carbon dioxide content of the blood, which does not increase with decreasing air pressure - the body can adapt to this situation by increasing the number of red blood cells. In order to climb the highest mountain in the world, it takes about five weeks to get used to the body slowly to the height.
Dangers in thin air
The main danger of low air pressure is fluid accumulation (edema) in the lungs and other body tissues (for example the brain). They arise as a result of an increase in blood pressure.
If one notices acute symptoms of altitude sickness when climbing the mountain, one should begin the descent; If only 1 or 2 symptoms appear, many consider acclimatization at the same level to be sufficient.
In severe cases, the person affected must be evacuated to lower heights. A further increase is life-threatening, and even when staying at the same level, the symptoms usually amplify and lead to death in extreme cases.