Human bodies function best at sea level. Down here, oxygen levels are sufficient for our brain and lungs. At much higher altitudes, our bodies cannot function properly.
But if climbers want to summit Everest, the world’s highest peak at 29,029 feet (8,848 meters or 5.5 miles) above sea level, they must brave what is known as the “death zone.”
This is the area with an altitude of over 8,000 meters, where there is so little oxygen that the body begins to die minute by minute and cell by cell.
In the death zone, climbers’ brains and lungs are deprived of oxygen, the risk of heart attack and stroke increases, and their judgment rapidly weakens.
“Your body breaks down and basically dies,” Shaunna Burke, a climber who climbed Mount Everest in 2005, told Business Insider. “It’s a race against time.”
In 2019, at least 11 people died on Everest, almost all of whom spent time in the death zone. It became one of the deadliest seasons on Everest in recent memory.
Some expedition companies blamed these deaths on overcrowding, noting that the peak was so choked with climbers during a rare spell of good weather that people were stuck in the death zone for too long.
On May 22, 2019, 250 climbers attempted to reach the summit, the Kathmandu Post reported, and many climbers had to wait in line to ascend and descend.
These extra, unscheduled hours in the death zone may have put the 11 people who died at higher risk, although it is difficult to determine the specific causes of each death.
One mountaineer said climbing Mount Everest is like ‘running on a treadmill and breathing through a straw’
At sea level, air contains about 21 percent oxygen. But at altitudes above 12,000 feet, oxygen levels are 40 percent lower.
Jeremy Windsor, a doctor who climbed Everest in 2007 as part of the Caudwell Xtreme Everest expedition, told Everest blogger Mark Horrell that blood samples taken from four climbers in the death zone revealed the climbers were surviving on just a quarter of the oxygen that they had. required at sea level.
“These were comparable to the evidence found in terminally ill patients,” Windsor said.
Five miles above sea level, the air has so little oxygen that even with supplemental air tanks, it can feel like “running on a treadmill and breathing through a straw,” according to climber and filmmaker David Breashears.
Climbers must acclimatize to the lack of oxygen
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 jumps to 140 beats per minute, increasing the risk of a heart attack.
Climbers must give their bodies time to acclimatize to the lung-crushing conditions in the Himalayas before attempting to summit Everest.
Expeditions generally make at least three trips up the mountain from Everest Base Camp (which is the highest of almost any mountain in Europe at 17,600 feet), going a few thousand feet higher with each successive trip before making a summit push.
During these weeks at high altitudes, 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 your blood, making it harder for the heart to pump blood around the body. This can lead to a stroke or a build-up of fluid in your lungs.
On Everest, a condition called high-altitude pulmonary edema (HAPE) is common – a quick check with a stethoscope can reveal a popping sound as the fluid leaking into the lungs rattles around.
Other symptoms include fatigue, a feeling of impending suffocation at night, weakness, and a persistent cough that produces white, wet, or frothy fluid. Sometimes the cough is so intense that it can crack or split ribs.
Mountaineers with HAPE are always short of breath, even when resting.
In the death zone, your brain can begin to swell, which can lead to nausea and a form of psychosis
Acclimatization to the altitudes of the death zone simply isn’t possible, high-altitude expert and physician Peter Hackett told PBS.
One of the biggest risk factors at 26,000 feet is hypoxia, the lack of adequate oxygen circulation to organs like your brain. If the brain doesn’t get enough oxygen, it can begin to swell, causing a condition called high-altitude cerebral edema (HACE). Essentially, it is HAPE for the brain.
This swelling can cause nausea, vomiting, and difficulty thinking and reasoning.
An oxygen-starved brain can cause climbers to forget where they are and enter a delirium that some experts consider a form of high-altitude psychosis.
Hypoxic climbers’ judgment is impaired and they have been known to do strange things like start shedding their clothes or talk to imaginary friends.
Other potential hazards include insomnia, snow blindness, and vomiting
Burke said that during the climb she suffered from a constant, relentless cough.
“Every second or third breath, your body gasps for air and you wake yourself up,” he said.
The air was so thin that he could not sleep properly.
“People will start to wear out,” Hackett added. “Sleep becomes a problem. Muscle loss occurs. Weight loss occurs.”
Nausea and vomiting from altitude-related illnesses, including HAPE and HACE, also cause a decrease in appetite. The glare from endless snow and ice can cause snow blindness – temporary loss of vision or burst blood vessels in your eyes.
Temperatures in the death zone never exceed zero degrees Fahrenheit. “Any exposed skin freezes immediately,” Burke said.
Loss of blood circulation to climbers’ fingers and toes can cause frostbite and in severe cases – if the skin and underlying tissues die – gangrene. Gangrenous tissue often needs amputation.
All this physical impairment and impaired vision can lead to accidental falls. Fatigue is always present, according to Burke.
“It takes everything to put one foot in front of the other,” he said.
Poor decision-making can also lead climbers to forget to re-clip a safety rope, wander off route, or fail to properly prepare life-saving equipment such as oxygen tanks.
Climbers climb the death zone in a day, but can wait in line for hours
Climbing the death zone is “a living hell,” Everest climber and 1998 NOVA expedition member David Carter told PBS.
Typically, climbers attempting the summit attempt to ascend and descend it in one day, spending as little time as possible in the death zone before returning to safer altitudes. But that frantic push to the finish line comes at the end of weeks of climbing.
Lakpa Sherpa, who has reached the summit of Everest nine times (more than any other woman on Earth), told Business Insider that the day a team attempts to reach Everest is by far the most difficult part of the trek.
To reach the top successfully, everything has to go right. Around 10 p.m., climbers leave Camp Four at 26,000 feet. The first part of their climb is done in the dark, illuminated by starlight and searchlights.
About seven hours later, climbers usually reach the summit. After a short rest full of celebrations and photos, the missions turn around, making the 12-hour journey back to safety and arriving (ideally) before nightfall.
This article was originally published by Business Insider.
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