Scary things that happen to the human body in the 'death zone' of Mount Everest

The human body functions best at sea level because the oxygen density in the air is sufficient for our brains and lungs to function. Conversely, at much higher altitudes, our bodies cannot function properly when the oxygen density is too thin.

Accordingly, climbers who want to conquer Mount Everest, the highest mountain in the world at 8,848 meters above sea level, will bravely cross the so-called "death zone".

"Running on the treadmill and breathing through a straw"

The death zone is an area above 8,000 meters where there is so little oxygen that the body's cells die by the minute. In the death zone, climbers' brains and lungs become starved of oxygen, their risk of heart attacks and strokes increases, and their judgment rapidly deteriorates.

" Your body is breaking down and basically dying. [The climb] suddenly becomes a race against time ," Shaunna Burke, a climber who conquered Everest in 2005, told Business Insider.

Group of people conquering the roof of the world - (Photo: Internet).

In 2019, at least 11 people died on Everest, most of them spending too much time in the death zone. It became one of the deadliest climbing seasons on Everest in recent years.

At sea level, the air contains about 21 percent oxygen. But above 12,000 feet, oxygen levels are 40 percent lower than average at sea level. Blood samples taken from four climbers in the death zone showed they survived on just a quarter of the oxygen they needed to survive at sea level, according to Jeremy Windsor, a doctor who climbed Everest in 2007.

' These numbers are comparable to those seen in patients near death ,' Windsor said.

At 8 kilometers above sea level, the oxygen in the air is so thin that even with supplemental oxygen tanks, climbers feel like they are " running on a treadmill and breathing through a straw ," according to filmmaker and climber David Breashears.

Mount Everest - (Photo: Internet).

Must adapt to hypoxia

Lack of oxygen leads to a myriad of health risks. When the amount of oxygen in your blood drops below a certain level, your heart rate spikes to as high as 140 beats per minute, increasing your risk of a heart attack.

Climbers must allow their bodies time to acclimatize to the harsh conditions of the Himalayas before attempting to summit Everest. Expeditions typically make at least three trips up the mountain from Everest Base Camp (at 18,000 feet, higher than almost any mountain in Europe). Each expedition moves to the next three camps, before making the final climb to the summit. At the fourth camp, most Everest expeditions begin their journey at midnight.

During the weeks at high altitude, the body begins to produce more hemoglobin (the protein in red blood cells that helps carry oxygen from the lungs to the rest of the body) to compensate.

But too much hemoglobin can thicken a person's blood , making it harder for the heart to pump blood around the body. That can lead to a stroke or fluid buildup in the lungs. On Everest, a condition called high-altitude pulmonary edema (HAPE) is common. A quick check with a stethoscope can detect strange sounds as fluid leaks into the lungs.

Everest Base Camp - Photo: Nat Geo.

Other symptoms include fatigue, a feeling of suffocation at night, weakness, and a persistent cough that produces white or frothy fluid. Sometimes the coughing is so severe that it can crack or dislocate ribs. Climbers with HAPE are always short of breath, even when resting.

Additionally, if the brain doesn't get enough oxygen, it can start to swell, causing a condition called high altitude cerebral edema (HACE).

This swelling of the brain can cause nausea and difficulty thinking and reasoning. An oxygen-deprived brain can cause climbers to forget where they are and fall into a state of delirium, which some experts consider a form of high-altitude psychosis. Hypoxic climbers' judgment becomes impaired and they have been known to act strangely, such as taking off their clothes or talking to imaginary friends.

Conquering Everest is still one of the most worthwhile challenges - (Photo: Internet).

Other dangers can include insomnia, snow blindness and vomiting. Climber Burke said she developed a persistent cough while climbing.

' Every second or third breath, your body gasps and you wake yourself up, ' she said. The air was so thin that she couldn't sleep well.

' The human body starts to deteriorate ,' Hackett added. 'Sleep becomes an issue. Muscle wasting happens. Weight loss happens .'

Nausea and vomiting from altitude sickness, including HAPE and HACE, also reduce appetite. The glare from snow and ice as far as the eye can see can cause snow blindness - temporary loss of vision - or even burst blood vessels in the eyes.

Any exposed skin freezes instantly. The loss of blood circulation to a climber's fingers and toes can cause frostbite, and in severe cases—if the skin and underlying tissue die—gangrene. The necrotic tissue often needs to be amputated. All of this physical weakness and poor vision can lead to fatal falls.

Poor decision making can also cause climbers to forget to clip their safety ropes, stray from the route, or fail to properly prepare life-saving equipment such as oxygen tanks.

However, the harsh conditions of the death zone cannot discourage the determination of those who are determined to conquer the roof of the world. In fact, history remembers many names that consider Mount Everest as a second home: Ms. Lhakpa Sherpa has climbed Mount Everest 9 times, she is the only woman in history to conquer Everest with an impressive number of times.

As technology has improved, climbing Everest has become safer than ever. The cold and lack of oxygen can now be compensated for with warm clothing and oxygen tanks; the journey to conquer Everest has become much easier than before.

But no matter how easy it is, the journey to conquer Everest is still the most severe test that a human can undergo. Individuals who have successfully conquered Mount Everest can proudly say: I have overcome the death zone, to stand on the top of the world.