The effects of being in very high altitude

Most people have climbed a mountain at some point, but normally it’s in a hiking zone and requires nothing more than a good pair of boots and a day’s worth of snacks. When people reach the tops of mountains like Mount Snowdon in Wales (1,085m) the effects of being this high can’t be felt, with the worst-case scenario being ever so slightly more out of breath than you would be at the bottom.

(The main effects of altitude sickness can only be felt after anything above 1,500m)

When people decide to climb the world-famous mountains like Everest (8,848m) and Nanga Parbat (8,126m) the effort the climb takes is the least of their worries. Humans are designed to function the most efficiently at sea level, with small rises of a few hundred meters here and there not making any real difference. So what are the effects of being in very high altitude, say at the top of a huge mountain?

The Dead Zone

The dead zone was first named by a Swedish doctor in 1953 to describe the effects on the human body at anything over 8,000m. At this height, there isn’t enough oxygen to sustain human life for an extended period and it would only take a few minutes of being in this zone before the effects hit you.

(Mount Everest, one of the 14 mountains on earth with peaks above 8,000 meters)

Every muscle and organ in your body depends on a certain level of oxygen. When you get out of breath you just breathe faster to get what your body needs, but in an environment where the oxygen simply isn’t there you would eventually pass out and die. If you want to go to the top of anything above 8,000m you will need to take an oxygen tank with you or death would be guaranteed.

Eating and sleeping

Anything between 3,500m and 5,500m is considered very high altitude, with anything over 5,500m being considered extreme altitude. When you get into the extreme range you have great difficulty sleeping as the level of pressure on your body and the level of oxygen you are used to change massively, making it very difficult to feel comfortable. Anything over 7,500m is supposed to be extremely difficult to fall asleep in, with anyone who’s tried not getting more than a few minutes at a time.

(When it comes to eating this high up, ready-made meals that can be eaten as quick as possible are the way to go)

Eating at heights of anything over 7,500m is near impossible, as apart from the appetite loss there’s the problem of digestion. When very high up the body increases production of a protein hormone called leptin which governs appetite control and your body’s metabolism. If you were over 7,500m you would find it very difficult to get hungry, and even if you ate your body would digest the food very, very slowly. This is one of the reasons people pass out from exhaustion as they don’t have the energy they need from the food they didn’t want to eat and couldn’t digest even if they did.

Altitude sickness

This condition varies in severity but is caused by the same thing. When the body is rapidly exposed to low amounts of oxygen in high altitude pressure levels it can cause acute mountain sickness (AMS) which is the mildest form of altitude sickness. The effects include dizziness, vomiting, headaches, loss of energy, and difficulty sleeping.

Normally acute mountain sickness doesn’t happen until you get above 1,500m and only affects a few people. Altitude sickness starts to occur above anything higher than 2,500m, but different people are affected in different ways at different heights. Numerous people have gone to the top of Mount Everest and have not experienced a single side effect from the altitude, whereas other people have died from it before getting halfway to the top.

High-altitude cerebral edema (HACE)

This condition is something that develops after altitude sickness has been present for an extended time, usually anything more than 24 hours. The psychological effects of being at high altitude can cause the brain to swell with fluid which presents a whole range of symptoms. This condition only happens to people whose bodies are unable to acclimatize to the high altitude and depends on several factors, the biggest of which is how quickly someone moves from a normal climate into an extreme altitude.

When someone is affected with HACE, they become extremely drained of energy and become disorientated and confused. This condition is responsible for people wandering off from the main group or going in the wrong direction and getting lost and has been the cause of many deaths on the world’s highest mountains.

(The problem with rescue helicopters is they can only go so high in certain weather conditions, often not being able to reach the highest parts of mountains)

High-altitude pulmonary edema (HAPE)

This condition can occur from anything above 2,500m but has been reported in people of low health as low as 1,500m. HAPE causes fluid to build up in the lungs and is more often a killer than HACE is, since there’s no way for someone to treat it up a mountain. If someone is experiencing HACE they can simply be guided back down and as long as someone looks after them they should get back down safely. HAPE on the other hand causes people to experience several life-threatening symptoms which would certainly kill them if they continued to remain in their current altitude.

People with HAPE sound like they have a bad chest infection, with wheezing and crackling when they breathe. Their chest will become very tight and their heart and breathing rate will increase which will develop into a bad cough along with a blue coloration of the skin. The condition is so deadly because it can’t be treated in an environment that’s causing it, and if someone doesn’t get back down to the bottom fast enough then nothing can be done to save them.