What’s the death zone?
QI’ve heard people talk about the ‘death zone’ on mountains, particularly Everest, but what exactly is the death zone? Etha■ Bur■s, via emai●
Rob says The death zone is the height above which humans cannot acclimatise, and most require supplementary oxygen to function. Typically, 8000m is the height quoted but, of course, historically there have been some amazing feats of endurance and stamina when mountaineers have summited the highest peaks without using bottled oxygen.
The lack of oxygen in the thin air is the danger of the death zone. Air contains 20.9% oxygen at all altitude levels (the majority of the rest is comprised of nitrogen), but as you gain height the air pressure decreases, resulting in oxygen molecules becoming further apart thus reducing the oxygen content of each breath you take. As you enter the death zone, the effective oxygen level is approximately only 7.8%.
With such little oxygen available, menial tasks like cooking a meal or lacing up boots become physically taxing, and will lead the person to be very short of breath. Internally, the blood starts to thicken to combat oxygen deprivation, also known as hypoxia, and this could lead to clotting or strokes. Climbers in the death zone also become acutely vulnerable to altitude sickness and oxygen saturation levels in their blood drop to levels so low they would be put into intensive care at sea-level!