Mount Everest Death Zone Explained

No living thing can survive more than a few days above 26,000' (8000m) also know as the Death Zone. Here Australia's most accomplished mountaineer, Andrew Lock talks about the debilitating effects of high altitude climbing, and trying to survive in the aptly named 'Death Zone'

📼 News Corp Australia

In mountaineering, the death zone refers to altitudes above a certain point where the pressure of oxygen is insufficient to sustain human life for an extended time span. This point is generally tagged as 8,000 m (26,000 ft, less than 356 millibars of atmospheric pressure). The concept was first conceived in 1953 by Edouard Wyss-Dunant, a Swiss doctor, who called it the lethal zone. All 14 peaks above 8000m in the death zones are located in the Himalaya and Karakoram of Asia.

Many deaths in high-altitude mountaineering have been caused by the effects of the death zone, either directly by loss of vital functions or indirectly by wrong decisions made under stress, or physical weakening leading to accidents. An extended stay above 8,000 metres (26,247 ft) without supplementary oxygen will result in deterioration of bodily functions and death.

Physiological background
The human body functions best at sea level where the atmospheric pressure is 101,325 Pa or 1013.25 millibars (or 1 atm, by definition). The concentration of oxygen (O2) in sea level air is 20.9% so the partial pressure of O2 (PO2) is about 21.2 kPa. In healthy individuals, this saturates hemoglobin, the oxygen-binding red pigment in red blood cells.

Atmospheric pressure decreases exponentially with altitude while the O2 fraction remains constant to about 100 km (62 mi), so PO2 decreases exponentially with altitude as well. It is about half of its sea level value at 5,000 m (16,000 ft), the altitude of the Mount Everest base camp, and only a third at 8,848 m (29,029 ft), the summit of Mount Everest.When PO2 drops, the body responds with altitude acclimatization. Additional red blood cells are manufactured; the heart beats faster; non-essential body functions are suppressed, food digestion efficiency declines (as the body suppresses the digestive system in favor of increasing its cardiopulmonary reserves);[9] and one breathes more deeply and more frequently. But acclimatization requires days or even weeks. Failure to acclimatize may result in altitude sickness, including high altitude pulmonary edema (HAPE) or cerebral edema (HACE).

Humans have survived for 2 years at 5,950 m (19,520 ft) [475 millibars of atmospheric pressure], which appears to be near the limit of the permanently tolerable highest altitude. At extreme altitudes, above 7,500 m (24,600 ft) [383 millibars of atmospheric pressure], sleeping becomes very difficult, digesting food is near-impossible, and the risk of HAPE or HACE increases greatly.

Bottled oxygen can help mountaineers survive in the death zone
In the death zone and higher, no human body can acclimatize. The body uses up its store of oxygen faster than it can be replenished. An extended stay in the zone without supplementary oxygen will result in deterioration of body functions, loss of consciousness and, ultimately, death. Scientists at the High Altitude Pathology Institute in Bolivia dispute the existence of a death zone, based on observation of extreme tolerance to hypoxia in patients with chronic mountain sickness and normal fetuses in-utero, both of which present pO2 levels similar to those at the summit of Mount Everest.

Mountaineers use supplemental oxygen in the death zone to reduce deleterious effects. An open-circuit oxygen apparatus was first tested on the 1922 and 1924 British Mount Everest expeditions; the bottled oxygen taken in 1921 was not used (see George Finch and Noel Odell). In 1953 the first assault party of Tom Bourdillon and Charles Evans used closed-circuit oxygen apparatus. The second (successful) party of Ed Hillary and Tenzing Norgay used open-circuit oxygen apparatus; after ten minutes taking photographs on the summit without his oxygen set on, Hillary said he "was becoming rather clumsy-fingered and slow-moving".

Physiologist Griffith Pugh was on the 1952 and 1953 expeditions to study the effects of cold and altitude; he recommended acclimatising above 15,000 feet (4,600 m) for at least 36 days and the use of closed-circuit equipment. He further studied the ability to acclimatise over several months on the 1960-61 Silver Hut expedition to the Himalayas.

#Everest #DeathZone

[PetraKann]

I was thinking about climbing at least one 8, 000m peak but now I think I will stick to peaks located in Australia

[edkiely]

All of that suffering and pain involved, yet thousands have made the endeavor over and over again and again!

[alphaomega]

This would be a great school 🏫 trip for kids. 😳

[missbmissb]

So what's the damn point of doing it 🤦

[anthonyejiofor]

You feel like your dying, and you're actually dying. ForEVER will you REST if you don't make it back down. Its interesting how people will still attempt, Goodluck to them and godspeed.

[abr]

Lol I felt all this climbing snowden in the U.K. felt like Everest for me it was my first ever climb I was smoking weed the night before lol

[gingersam]

You have an oxygen bottle but cannot get enough oxygen. It does not make sense. Something else is in play here.
Can somebody explain it to me?

[jokers]

There are lots of situations in which humans need supplemental oxygen to survive, such as outer space, in the ocean, caves, hospitalization, pilots, etc. High elevation alpine climbing is not special in this way. The problem with high elevation climbing is in the cost of using said supplemental oxygen. The cost is in transporting it. Most climbers are not capable of transporting all of the oxygen equipment they would need to the elevation they would need it, they must rely on poor people to transport it for them and this has limitations. Following this logic, the root problem is capitalism, not the high elevation. It is literally the limitations of the capitalist system which causes so many deaths at high elevation climbing. In a future socialist world hundreds of years from now, the wealth and technology will be much more advanced where supplemental oxygen is readily available and the dangers of high elevation climbing will be minimized if not completely eliminated. I am NOT just talking about oxygen masks for breathing. I am talking about much more advanced pressurized climbing suits, similar to what astronauts use but in the future they will be much more advanced to allow seamless climbing while being safe and pressurized. Sure there are other dangers such as high speed wind, which can also be overcome with technology.

[kevinrice]

Sounds like detoxification from narcotics or worse 🤔 and FU46

[noneyab]

The way he’s describing it, sounds so appealing and really fun. Sign me up. 🏔⛺️😩🥶