GASP! Take a (Very) Deep Breath! The Deadly Effects of Altitude and How to Fight Back!

The human body has incredible capabilities. It can adapt to deep sea pressure, it can survive extremes of heat and cold. It can rebuild after disease and famine.
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 tests 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 climbers 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 be experienced. 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. 
1. Which mountain range has the greatest acclimatisation challenges for climbers?
2. Heights above 8,000 metres are the most severe the human body can encounter. How many 8,000-metre peaks are there on planet earth? 
3. Have any human beings climbed all of the world’s 8,000-metre peaks? Any British climbers? 
4. Climbing 8,000-metre peaks without supplementary oxygen is the ultimate challenge. Has any climber done all of them in this way?
The human body starts to acclimatise at 2,500 metres above sea level ... roughly the altitude of this first trekking day. © Matt Dickinson   
Crossing a suspension bridge at 3,000 metres. At this altitude trekkers begin to lose their appetite and may feel breathless. © Matt Dickinson  
4,000 metres on the way to Everest. By now teams might be experiencing headaches and nausea. Keeping hydrated is vital. © Matt Dickinson  
At 5,000 metres the altitude is enough to provoke serious illness. Going slowly and staying several days at the same height is the right way to adapt. © Matt Dickinson  
As the human body ascends to 6,000 metres, the blood begins to thicken. More red blood cells are being produced to help the body cope with the thin air. © Matt Dickinson  
Everest climbers repeatedly climb up sections of the mountain to continue to adapt to the thin air. At least six weeks of preparation is necessary to go above 8, 000 metres. © Matt Dickinson  
Matt's video blogs from Jagged Globe's Everest expedition are now available on YouTube and Vimeo