How do I breathe in a 1600m run

That makes the height with your body

The heart itself can no longer cope with the adverse conditions and can only beat with a maximum of 120 beats per minute. The average survival time at this level is two to three days.

The senses now simulate wild things under the lack of oxygen. Because the brain is no longer able to process information properly. Mountaineers report how they had the impression of walking next to themselves over 8000 meters or how they saw people who were not there.

Water vapor displaces oxygen

On the summit of Everest, the body consumes large amounts of water through breathing alone. Behind this is a mechanism that the body cannot easily change: The humidification of the breath: While the oxygen partial pressure in the lungs adapts to the external conditions and also falls as the outside air pressure falls, the water vapor partial pressure always remains the same. It stays constant at 47 mmHg, no matter how high you climb - because it only depends on body temperature. The air in the lungs contains more and more water vapor due to the falling oxygen content: from 6.2 percent water vapor at sea level to 19 percent at the summit of Everest.

For the mountaineer this means: the higher it goes, the greater the proportion of water vapor molecules in the lungs. As a result, there is less space for oxygen molecules. The alveoli can absorb even less of it because oxygen comes by less often. However, the lungs want to ensure that more oxygen molecules are in a smaller space so that they can conduct enough of them into the blood. But she can't get rid of the water vapor anyway. So she tries desperately to make room for the oxygen by exhaling more carbon dioxide: The climber is now hyperventilating. That doesn't bring much. Even very fast breathing hardly brings the oxygen volume in the lungs over 13 percent.

Several milliliters of water lost - only through breathing

And now it all comes together: The mountaineer breathes faster because his lungs get less oxygen. So the lungs have to humidify more air in a short time. In the dry, cold air on the mountain, even more water vapor is needed for this. The loss of water as a result is immense: within an hour, the body loses a quarter of a liter of water only through breathing. Those who cannot keep up with drinking increase the risk of thrombosis, frostbite and inflammation. The performance decreases. In addition, the uptake of oxygen molecules is reduced by a good 70 percent due to the low air pressure, which means that the oxygen saturation in the blood drops to 50 percent of its original level. The brain is under-supplied with oxygen and there is a risk of functional disorders. Brain cells can die and brain damage can remain. Quite a few climbers lose toes, fingers or more to frostbite.

In the end, sometimes just giving up helps

The data on successful ascent of Mount Everest are sparse. A 2008 study looked at deaths between 1921 and 2006. The result: the death rate above the base camp, which is just over 5000 meters, was 1.3 percent. From an estimated tens of thousands of attempts at ascent since 1921 until today, around 5000 people have reached the top, some of them several times, as the expedition leader and climber Alan Arnette writes on his blog.

Many of them were helped by oxygen bottles, which most climbers take with them up the mountain to cope with the thin air. Another thing that has already saved the lives of some mountaineers is to turn back when the body no longer participates. The journalist and climber Jon Krakauer has written a book about his ascent to the Everest peak and described cases in which mountaineers turned around a few meters from the summit - and perhaps only because of that survived. In the year when Krakauer conquered the summit, one of the worst disasters occurred on the mountain: a change in the weather locked dozens of climbers on the mountain. More than 30 of them froze to death, fell, died of exhaustion or are otherwise lost.

You cannot climb higher on earth than the summit of Mount Everest. Researchers believe that the absolute height limit for humans is only slightly higher. No human body should be able to withstand an altitude of more than 9,000 meters.