The human body functions best at sea level due to the sufficient oxygen density in the air for our brain and lungs to operate. Conversely, at much higher altitudes, our bodies struggle to function normally as the oxygen density becomes too thin.
Accordingly, climbers wishing to conquer Mount Everest, the highest peak in the world at an elevation of 8,848 meters above sea level, must bravely navigate what is known as the “Death Zone.”
“Running on a treadmill while breathing through a straw”
The Death Zone refers to areas above 8,000 meters, where the oxygen is so scarce that cells in the body begin to fade minute by minute. In the Death Zone, climbers experience oxygen deprivation in their brains and lungs, increasing the risk of heart attacks and strokes, while their judgment capabilities deteriorate rapidly.
“Your body is breaking down and is essentially dying. [The climb] suddenly becomes a race against time,” Shaunna Burke, a climber who reached the summit of Everest in 2005, told Business Insider.
The team conquering the roof of the world – (Photo: Internet).
In 2019, at least 11 people died on Mount Everest, most of whom spent too long 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% oxygen. However, at altitudes above 3.6 kilometers, the oxygen level is over 40% lower than the average at sea level. According to Jeremy Windsor, a doctor who climbed to the summit of Everest in 2007, blood samples taken from four climbers in the Death Zone showed they survived with only one-fourth of the oxygen they needed to survive at sea level.
“These numbers can be compared to those of patients nearing death,” Windsor said.
At an altitude of 8 kilometers above sea level, the oxygen in the air is so diluted that even with supplemental oxygen tanks, climbers feel like they are “running on a treadmill while breathing through a straw“, according to filmmaker and climber David Breashears.
Mount Everest – (Photo: Internet).
Adapting to Oxygen Deprivation
The lack of oxygen leads to numerous health risks. When your blood oxygen levels drop below a certain point, your heart rate can spike up to 140 beats per minute, increasing the risk of heart attack.
Climbers must give their bodies time to adapt to the harsh conditions of the Himalayas before attempting to reach the summit of Everest. Expedition teams typically make at least three trips up the mountain from Base Camp Everest (at an altitude of 5.3 kilometers, higher than almost any mountain in Europe). Each climbing team will successively move up to the next three camps before making the final ascent to the summit. At the fourth camp, most teams begin their summit attempt at midnight.
During the weeks spent at high altitude, the body starts to produce more hemoglobin (the protein in red blood cells that carries oxygen from the lungs to the rest of the body) to compensate.
However, too much hemoglobin can thicken the blood, making it harder for the heart to pump blood throughout the body. This can lead to strokes or fluid accumulation in the lungs. On Everest, a condition known as High Altitude Pulmonary Edema (HAPE) is quite common. A quick check with a stethoscope can detect unusual sounds when fluid leaks into the lungs.
Base Camp Everest – Photo: Nat Geo.
Other symptoms include fatigue, a feeling of suffocation at night, weakness, and persistent coughing producing white or frothy fluid. Sometimes the coughing can be so severe that it can crack or dislocate ribs. Climbers suffering from HAPE always feel short of breath, even at rest.
Additionally, if the brain does not receive enough oxygen, it can start to swell, leading to a condition called High Altitude Cerebral Edema (HACE).
This swelling in the brain can cause nausea, difficulty thinking and reasoning. An oxygen-deprived brain can make climbers forget where they are and fall into a delirious state that some experts consider a form of altitude-induced mental disorder. The judgment abilities of oxygen-deprived climbers deteriorate, and they are known to engage in bizarre behaviors such as starting to undress or talking to imaginary friends.
The journey to conquer Everest remains one of the most challenging endeavors – (Photo: Internet).
Other dangers may include insomnia, snow blindness, and vomiting. Climber Burke reported that during her ascent, she suffered from constant coughing.
“With every second or third breath, your body gasps for air, waking you up,” she said. The air was so thin that she couldn’t sleep well.
“The condition of the human body will start to deteriorate,” Hackett added. “Sleep becomes an issue. Muscle wasting occurs. Weight loss occurs.”
Nausea and vomiting from altitude-related illnesses, including HAPE and HACE, also diminish appetite. The blinding light from the glaring ice and snow can cause snow blindness – temporary loss of vision, or even burst blood vessels in the eyes.
Any exposed skin freezes instantly. Loss of blood circulation to climbers’ fingers and toes can lead to frostbite, and in severe cases – if the skin and underlying tissues die – necrosis. Necrotic tissue often needs to be surgically removed. All of this physical weakening and poor vision can lead to fatal falls.
Making wrong decisions can also lead climbers to forget safety harnesses, stray from the path, or improperly prepare essential safety equipment such as oxygen tanks.
Despite this, the harsh conditions of the Death Zone cannot deter the determined individuals seeking to conquer the roof of the world. In fact, history remembers many names who consider Everest their second home: Lhakpa Sherpa has reached the summit of Everest nine times, making her the only woman in history to achieve such a remarkable feat.
As science and technology have advanced, the journey to climb Everest has become safer than ever. The cold and oxygen deprivation can now be countered with warm clothing and oxygen tanks; the path to conquer Everest is much easier than before.
However, no matter how easy it may seem, the journey to conquer Everest remains one of the harshest trials a person can endure. Individuals successful in reaching the summit of Everest can proudly say: I have overcome the Death Zone to stand on top of the world.
