The Sports Gene: Inside the Science of Extraordinary Athletic Performance (23 page)

The amount of oxygen in the blood is determined by two factors: how much hemoglobin one has and its “oxygen saturation,” or how much oxygen that hemoglobin is carrying. Because there is so little oxygen in their air, many of the hemoglobin molecules in the blood of the Andean highlanders rush through the body without a full load of oxygen—like roller coaster cars with few passengers. But the Andeans make up for it by having many more cars. This is not necessarily good from an athletic standpoint. Andeans have so much hemoglobin that their blood can become viscous and unable to circulate well, and some Andeans develop chronic mountain sickness.

Nineteenth-century scientists also saw that Europeans who traveled from sea level to altitude responded the same way, by producing more hemoglobin. So the book on altitude adaptation was closed for almost a century—until the 1970s, when Nepal and Tibet began to open to foreigners.

Cynthia Beall, an anthropology professor at Case Western Reserve University in Cleveland, started visiting to study Tibetans and Nepalese Sherpas who can live as high as eighteen thousand feet. To her surprise, Beall found that Tibetans had normal, sea-level hemoglobin
values, and low oxygen saturation, lower than people at sea level.
Few roller coaster cars, and many of them weren’t full.

Most Tibetans have a special version of a gene, EPAS1, that acts as a gauge, sensing the available oxygen and regulating the production of red blood cells so that the blood does not become dangerously thick. But it also means Tibetans don’t have the increase in oxygen-carrying hemoglobin that Andeans do.
“So, how exactly are they surviving here?” Beall asked herself. “The oxygen in their blood seems very low, but they’re somehow delivering enough to function normally.”

Eventually, Beall determined that Tibetans survive by having extremely high levels of nitric oxide in their blood. Nitric oxide cues blood vessels in the lungs to relax and widen for blood flow. “The Tibetans have 240 times as much nitric oxide in the blood as we do,” Beall says. “That’s more than in people at sea level who have sepsis,” a life-threatening medical condition. So Tibetans adapted by having very high blood flow in their lungs, and they also breathe deeper and faster than native lowlanders, as if they’re in a constant state of hyperventilation. “They’re spending more energy doing that,” Beall says.

In 1995, Beall and a team moved on to the remaining population in the world that has lived at high altitude for thousands of years: Ethiopians, and specifically the Amhara ethnic group living at 11,600 feet along the Rift Valley. Yet again, she found an altitude biology unique in the world. The Amhara people had normal, sea-level allotments of hemoglobin and normal, sea-level oxygen saturation.
The same number of roller coaster cars as sea-level natives and nearly all of them were filled, just as in sea-level natives.
“If we didn’t know we were at altitude, I would’ve said we were looking at sea-level people,” Beall says. It’s not entirely clear how the Amhara pull this trick off. But Beall has preliminary data on Amhara Ethiopians that shows they move oxygen unusually rapidly from the tiny air sacs in their lungs into their blood.

New Zealand’s Peter Snell, former mile world record holder turned medical researcher, theorized that enhanced transfer of oxygen from the lungs to the blood might be an advantage for people with altitude
ancestry when they came to run at sea level. “It’s possible,” Beall says of that prospect. She once raised it in a paper, but she’s adamant that nobody really knows. Plus, she saw the enhanced oxygen diffusion in her Amhara data, and most of the top Ethiopian runners are Oromo. An Oromo man holds the world records in the 5K and 10K, and an Oromo woman holds the women’s 5K record. (Scientists tracked the Oromo man, Kenenisa Bekele, over two runs at 6:30-per-mile pace, one at just under five thousand feet, and one above ten thousand feet. Astoundingly, his average heart rate only increased from 139 beats per minute to 141 on the higher run.)

Unlike the Amhara, who have been at altitude for thousands of years, Beall says that the pastoralist Oromo moved up from sea level just five hundred years ago. A foreigner would not distinguish Amhara and Oromo people on sight, but in terms of their altitude response, Beall would never confuse them.

Beall tested Oromo people living at about the altitude of Denver, “so you wouldn’t expect to see much,” she says, in terms of elevated hemoglobin. “But they already had more than a gram of hemoglobin more than the Amhara at a comparable altitude.” And the hemoglobin was packed with oxygen. “Their hemoglobin level was definitely higher than you would expect from a random group of lowlanders,” she says. Whereas the Amhara had low hemoglobin even at high altitudes, the Oromo had high hemoglobin even at moderate altitudes.

For one, these differences emphasize the diversity of physiology between peoples who have lived at altitude for different spans of history, and for whom evolution has landed on novel genetic solutions. Himalayans and Amhara Ethiopians are thought to have lived at altitude for thousands and perhaps tens of thousands of years, and Andeans for a shorter span, which may explain why Andeans are not yet fully adapted to their extraordinarily high homeland—and why they greatly elevate hemoglobin, just as lowlanders who go to altitude. (Like the Oromo, Kenya’s Kalenjin are relatively new altitude dwellers, having settled at altitude no more than two thousand years ago.)

As for Beall’s data from the Oromo—the ethnic group of the majority of top Ethiopian runners—they smack of altitude
responders.
The Oromo she tested increased their hemoglobin markedly even at altitudes below a mile high. And not only do different ethnic groups respond biologically to altitude in unique ways, there is also tremendous variation among individuals from the same ethnic group.

In 2003, a team of scientists from Norway and Texas exposed athletes to 9,200 feet of altitude for one day and looked at changes in the levels of the hormone EPO—which spurs the body to produce red blood cells. (Cheating endurance athletes inject EPO in an effort to force their bodies to produce more red blood cells.) The variation ranged from an athlete whose EPO levels declined, to another whose levels increased more than 400 percent.

In separate work on runners who trained for a month at altitude, those whose supply of red blood cells increased 8 percent on average improved their 5K time by thirty-seven seconds upon returning to sea level, whereas those who had no increase in red blood cells did slightly worse than they had previously in the 5K when they returned to sea level. As with other forms of training—and all manner of medicine—altitude training is most effective if tailored to each athlete’s unique physiology.

The idea of individualized responses to altitude rings true to Bob Larsen, who coached Americans Deena Kastor and Meb Keflezighi—winners, respectively, of a bronze and a silver medal in the 2004 Olympic marathon. “We have some evidence that some people have to be there for a long time,” Larsen says. “It really took Deena about two years of being at altitude. Meb was quick. He was a little flat his second week at altitude, but after about six weeks he set the American record [in the 10K].”

Even with individual variation in altitude response, there seems to be a rough “sweet spot” for training, an altitude where red blood cell production increases, but not too much. Where the air is thin, but not too thin. Andeans and Himalayans live far above it. Anecdotally, the
sweet spot is around six to nine thousand feet, high enough to cause physiological changes, but not so high that the air is too thin for hard training.

As it happens, the ridges of the Rift Valley in Ethiopia and Kenya are plumb in the sweet spot. The foremost training bases in Kenya: Eldoret, 6,890 feet. Iten: 7,545 feet. Kapsabet: 6,395 feet. Kaptagat: 7,870 feet. Nyahururu: 7,215 feet. The major training cities in Ethiopia, Addis Ababa and Bekoji, both have running sites around 8,000 to 9,000 feet. In the United States, pro endurance athletes hunting for the sweet spot train in Mammoth Lakes, California: 7,880 feet. Or Flagstaff, Arizona: 7,000 feet.

Preferable to moving to altitude to train is being born there. Altitude natives who are born and go through childhood at elevation tend to have proportionally larger lungs than sea-level natives, and large lungs have large surface areas that permit more oxygen to pass from the lungs into the blood. This cannot be the result of altitude ancestry that has altered genes over generations, because it occurs not only in natives of the Himalayas, but also among American children who do not have altitude ancestry but who grow up high in the Rockies. Once childhood is gone, though, so too is the chance for this adaptation. It is not genetic, but neither is it alterable after adolescence.

No scientist contends that altitude alone forges tireless runners or that it is impossible to become a great distance runner without altitude training. But some, like Pitsiladis, say that it’s simply far less likely. A helpful combination, perhaps, is to have sea-level ancestry—so that hemoglobin can elevate quickly upon training at altitude—but to be born at altitude, in order to develop larger lung surface area, and then to live and train in the sweet spot. This is exactly the story of legions of Kalenjin Kenyans and Oromo Ethiopians.

Coincidentally, or maybe not, Shalane Flanagan, the fastest current American female marathoner—and daughter of a former marathon world record holder—was born and spent part of her childhood in the foothills of the Rockies, in Boulder, Colorado, above a mile
high. Ryan Hall, the fastest current male American marathon runner, was raised in Big Bear Lake, California: seven thousand feet, and up.

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Drive north toward the Sangre de Cristo Mountains, to the point where the black asphalt disappears beneath a wash of brown rock and dirt, and you will be in Truchas, New Mexico, at eight thousand feet.

Not long before the road vanishes, on the left just past a cattle gate, is a low-slung adobe house with a yellow school bus in the yard. The bus hasn’t moved in decades. In the alfalfa field out back, eighty-five-year-old Presiliano Sandoval is working in the heat. His fingers, which haven’t been parallel since before the school bus worked, are curled around the wooden handle of a shovel.

In the adobe house, Presiliano raised the greatest American athlete no one remembers. Even now, Anthony Sandoval lives just an hour’s drive to the southwest, in Los Alamos. Anthony was one of six children, but Presiliano could tell that he was different. Presiliano remembers Anthony, at eight years old, was content to walk alone in the winter into the mountains with a hammer and wedge to split frost-hardened piñon trees.

By the summer of sixth grade, three times a week Anthony was taking his father’s cows several miles into the mountains so they could graze. “It was never less than two hours of walking,” with sporadic running mixed in, Anthony says. He had always been a good runner, but when he returned from that summer, he was by far the fastest boy in school.

Presiliano yearned for his son to get an education that Truchas could not provide, so he enrolled him at Los Alamos High School an hour away, where Anthony was surrounded by the sons and daughters of the physicists and nuclear engineers who worked at Los Alamos National Lab, birthplace of the atomic bomb. The locale was so secretive during World War II that babies born in Los Alamos had “P.O. Box 1663” listed as the city of record on their birth certificates.

At the start of Sandoval’s freshman year, a friend suggested he go out for cross country. “I said, ‘What’s cross country?’” Sandoval recalls. “But I went out that year, and ended up second in the state. And then I never lost another race after that in high school.” In his junior year, Sandoval ran farther than 12.5 miles in 60 minutes, setting the under-twenty world record for a one-hour run. In 1972, his senior year, then 5'6" and 98 pounds, Sandoval won the junior national championships in cross-country.

The Sandovals had no phone in the adobe home in Truchas, but reams of recruiting letters were mailed straight to Los Alamos High School. The boy whose aunts and uncles had been shepherds and uranium miners would go to Stanford. In Palo Alto, Sandoval excelled in class, earning admission to med school while training sixty to seventy miles a week.

At the Pac-8 championships in 1976, his senior year of college, Sandoval won the 10K, just ahead of three Kenyans running for Washington State, one of whom would later set the world record. And then, off his college track training, Sandoval jumped into the 1976 Olympic marathon trials. He finished fourth, one minute and one spot off the Olympic team. So away he went to med school, figuring he would have other chances at the Olympics, when he could actually train for the marathon distance.

But Sandoval was insatiably interested in serving people and in medicine, so he pursued cardiology, a study-intensive specialty that did not accommodate marathon training. Still, Sandoval’s ability was evident. In 1979, immersed in his medical studies, Sandoval managed just thirty-five miles per week of training. It was enough for him to run a 2:14 marathon, an utterly preposterous result given what was essentially a jogger’s training regimen. (A baseball fan might think of this as akin to a guy who takes batting practice in his local beer league and then hits .300 against major league pitchers.)

In 1980, with the Olympics again approaching and still deep in med school, Sandoval carved out a few months of rigorous training. It
was enough. At mile 23 of the Olympic Trials in Buffalo, he simply ran away. He finished in 2:10:19, a U.S. Olympic Trials record that stood for twenty-seven years. “Tony was, at that point, probably the fastest runner in the world,” says Frank Shorter, the last American man to win gold in the Olympic marathon.

But it was the year of the Moscow Olympic Games, and President Jimmy Carter decreed that the U.S. would lead sixty-four countries in an Olympic boycott to protest the Soviet invasion of Afghanistan. Sandoval, like 465 other American athletes, was forced to stay home.

As he embarked on his career as a cardiologist, Sandoval began a pattern that would last more than a decade: he would try, but struggle, to ramp up his training each time the Olympics approached. In 1984, he finished sixth at the trials. In 1988, in the middle of a cardiology fellowship, he finished twenty-seventh.