In the Genes: Mountaineer Built for Peak Performance
for National Geographic News
|November 22, 2004|
Most mountaineers who traipse above elevations of 23,000 feet (7,000
meters) or so opt for bottled oxygen. It helps them stay alert and
focused on reaching the summit, not to mention more fundamental
objectives, such as returning to base camp alive.
At high altitude, oxygen is less dense. As Robert Schoene, an expert on high-altitude pulmonary medicine at the University of California, San Diego, noted, "In order to obtain the amount of oxygen that you need for energy combustion or generation, you need to breathe a lot more."
Ed Viesturs, a Seattle, Washington-based climber, is a rare exception. He has summitted, without the aid of supplemental oxygen, 13 of the 14 highest mountains in the world. The peaks rise more than 8,000 meters (26,250 feet) above sea level.
Next year Viesturs aims to summit the last unclimbed mountain on his list, Annapurna. The mountain rises 8,091 meters (26,545 feet) in the Nepalese Himalaya.
If successful, Viesturs will close the book on Endeavor 8,000, his quest to become the second person in the world, and the first American, to climb the 14 highest peaks on Earth without the use of supplemental oxygen.
"It was a challenge to see if I could climb mountains for what they are," Viesturs said.
Schoene said Viesturs's unique blend of physical characteristics and mountain savvy allow him to take on such a challenge: Physically, Viesturs has aerobic abilities on par with the world's elite athletes. Mentally, he's among the most efficient mountaineers in the business.
Viesturs got serious about mountaineering in the late 1970s while a college student at the University of Washington in Seattle.
"As I was climbing early on, I would notice at the end of the day that I performed better than the other folks I was with," he said. "I felt better during the climb, and as I went higher and higher, it wasn't as big a deal to me as to other people."
In 1997 Schoene performed a series of physiological tests on Viesturs and found the mountaineer has a high VO2 max, a measure of the amount of oxygen the body can take in and use each minute. Only world-class endurance athletes such as cyclist Lance Armstrong have a higher VO2 max than Viesturs, Schoene said.
Viesturs also has an anaerobic threshold of about 90 percent, meaning he can climb for hours on end using 90 percent of his maximum exercise capacity without collapsing. Most people collapse at levels around 60 percent.
But more than this physiology, Schoene said, Viesturs moves with incredible efficiency. At extreme altitude, any exertion, even getting out of a sleeping bag, leaves climbers short of breath. Efficient movement is essential, Schoene said.
This efficiencycombined with training, mountain savvy, and a desire to succeedputs Viesturs on top of the world time and again. He reached the summit of Mount Everest for the sixth time in May.
"I picked the right sport," Viesturs said.
While Viesturs does excel at high-altitude climbing, not even he can fly from his home in sea-level Seattle to Nepal and climb Everest the very next day. "For anybody to do anything at these altitudes, the body needs to adapt," Schoene said.
The body's task is to deliver oxygen from the air to mitochondria in the cells of muscle tissue, where it is turned into energy, Schoene explained. Getting the oxygen to the mitochondria, however, is a step-by-step process, each step affected by a change in altitude.
A person at high altitude will first notice an increase in their breathing rate. This reflects the need to get more air into their lungs. Their heart has to pump more blood to pick up and deliver oxygen from their lungs to body tissues where cells reside. There, oxygen must diffuse from tiny blood vessels to cells, where the gas can be metabolized by mitochondria.
"Everyone is a little bit different in terms of speed of acclimation and in terms of coping," Schoene said. A general rule of thumb for mountain climbers is to spend two nights at the same elevation for every 3,000 feet (915 meters) gained above about 10,000 feet (3,000 meters).
People who ascend too high too quickly may experience what is known as acute mountain sickness. Common symptoms are shortness of breath, headaches, loss of appetite, and insomnia, which Schoene said are all related to the lack of oxygen at altitude.
Once climbers venture above about 20,000 feet (6,000 meters), they enter what is known as the death zone. It is the point at which mountaineers can no longer escape the effects of altitude and can only hope to minimize them.
Above the death zone is where many mountaineers begin to lose their focus and make fatal errors of judgment, an affliction that Viesturs escapes.
"I do really well with less oxygen," he said. "I've gone to the top of Everest without oxygen and sat on top for an hour and had lunch. I was not crawling on my hands and knees."
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