It also has systems to cope with extreme altitude, but, as climbers know, you have to approach things in the right way or things can quickly go wrong.
Everest is the ultimate test. To take the body to 8,848 metres pushes the human body to the absolute limit. On the summit there is just 30% of the oxygen we normally breathe. This puts the whole body under pressure:
- Cells cannot rebuild and repair themselves.
- Mental ability and decision making is severely impaired.
- The lungs and brain may suffer catastrophic effects ... namely water build up and subsequent failure.
- The blood may become so thick it causes strokes or even a heart attack.
So, what is the secret? How do Everest climbers manage to adapt?
The answer is to go as slowly as possible, gaining height in a series of gradual stages (with rest days built in) so that the body can produce more red blood cells to cope with the gradually thinning air. The climber's motto is ‘climb high, sleep low,’ pushing the body as hard as possible during the day by gaining perhaps 500 metres or even 1,000 metres of height then dropping back down and sleeping at a lower altitude.
Using this system, it takes about two weeks to be able to live at base camp level, at 5,400 metres.
Even so, sleeplessness, headache, loss of appetite and nausea may still occur. Even the most experienced climbers get these symptoms from time to time.
If you rush to high altitude and get sick there is only one solution: go down as fast as possible. The thicker air will quickly restore normal bodily functions.
On Everest most climbers resort to using supplementary oxygen above 8,000 metres. Fed from a tank, a trickle of air helps the climber to gain height while still remaining warm and strong.