Isegoria

Kenya’s long-distance runners live at altitude, David Epstein notes (in The Sports Gene), but some people ask, “If it’s just the altitude, where are the runners from Nepal?”:

The “Nepali runners” question, though, is actually irrelevant to the Kenyan and Ethiopian running phenomena, and not only because the Himalayan climate does not foster a narrow body type. One clear point of science is that the genetic means by which people in different altitudinous regions of the world have adapted to life at low oxygen are completely distinct. In each of the planet’s three major civilizations that have resided at high altitude for thousands of years, the same problem of survival is met with different biological solutions.

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By the late nineteenth century, scientists figured they understood altitude adaptation. They had studied native Bolivians, living in the Andes at higher than thirteen thousand feet. At that altitude, there are only around 60 percent as many oxygen molecules in each breath of air as at sea level. In order to compensate for the scarce oxygen, Andeans have profuse portions of red blood cells and, within them, oxygen-carrying hemoglobin.

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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.

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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.

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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.

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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.

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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.

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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.

David Epstein explores (in The Sports Gene) Kenya’s dominance in long-distance running:

In the 1964 Olympics, just the third ever in which Kenya competed, a Kipsigis runner named Wilson Kiprugut won bronze in the 800-meters. Four years later, in the altitude of Mexico City, Kenya was the dominant distance running power, winning seven medals in middle- and long-distance events.

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“The conventional wisdom was that blacks could sprint, but that anything that required tactical sophistication, or discipline, or training,” he says, “this was the white man’s province.”

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The 4.9 million Kalenjin people represent about 12 percent of Kenya’s population, but more than three quarters of the country’s top runners.

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Manners wrote that a part of traditional life for Kalenjin warriors was the practice of cattle raiding. Essentially, it entailed stealthily running and walking into the land of neighboring tribes, rounding up cattle, and escorting them back to Kalenjin land as quickly as possible. Cattle raiding was not considered theft so long as the raiders weren’t filching the cattle from the same subtribe within the Kalenjin. “The raids were conducted largely at night,” Manners wrote, “and sometimes ranged over distances as great as 100 miles! Most raiding parties were group ventures but each muren [or warrior] was expected to at least do his share.”

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A muren who brought back a large number of cattle from a raid was hailed as a courageous and athletic warrior and could use his cattle and prestige to acquire wives.

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Korir was thrust into the 3,000-meter steeplechase — a race just shy of two miles that includes hurdles — and in his third-ever attempt at the event won the national junior college championship. Four years later, Korir was the third-ranked steeplechase runner in the world.

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Or the one about Julius Randich, who arrived at Lubbock Christian University in Texas a heavy smoker with no competitive running background. By the end of his first year, 1991–92, Randich was the national small-colleges (NAIA) champion in the 10K. The following year, Randich set NAIA records in the 5K and 10K and was named the outstanding athlete in any sport in the NAIA.

Kalenjin runners became all the rage among NAIA coaches, and several others would win the 10K national championships after Randich, including his younger brother Aron Rono, who won it four straight times.

Rotich, the son of a prosperous Kalenjin farmer, arrived at South Plains Junior College in Texas in 1988, having lived a “comfortably sedentary” life, as Manners describes it. Rotich, a stout 5’8″ and 190 pounds, quickly burned through most of the $10,000 his father had given him for two years of living expenses and tuition. “But rather than return home in disgrace,” Manners wrote, “Paul . . . decided to train in hopes of earning a track scholarship.” Rotich trained at night to avoid the embarrassment of being seen. That concern would be short-lived, as he made the national junior college cross-country championships in his first season. He went on to become a ten-time All-American in cross-country and indoor and outdoor track. As Manners reported, when Rotich returned to Kenya and detailed his running exploits to a cousin, the cousin replied: “So, it is true. If you can run, any Kalenjin can run.”

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Consider this: seventeen American men in history have run a marathon faster than 2:10 (or a 4:58 per mile pace); thirty-two Kalenjin men did it just in October 2011.

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For example: five American high-schoolers have run under four minutes in the mile in history; St. Patrick’s High School, in the Kalenjin training town of Iten, once had four sub–four milers in school at the same time.

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Wilson Kipketer, a former St. Patrick’s student who became a Danish citizen and held the 800-meter world record from 1997 to 2010, does not hold his own high school’s record.

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The kids in his time trials generally come from elite, highly selective, government-funded boarding schools, and essentially none of them have any racing experience.

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Each year, about half of the boys in the time trial will run faster than 5 minutes and 20 seconds in the 1,500-meter time trial, on a shoddy dirt track, above seven thousand feet. (The 1,500 is about 100 meters shy of a mile, and 5:20 translates to a mile time just over 5:40.)

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In the tryout in 2005, a boy named Peter Kosgei ran 4:15 with no real training. Kosgei was accepted to Hamilton College in Clinton, New York, and quickly became the best athlete in the college’s history. In his freshman year, Kosgei won the Division III 3,000-meter steeplechase national title. By the end of his junior year, he had compiled eight more national titles in cross-country and track.

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Evans Kosgei — no relation to Peter — held down a 3.8 GPA in computer science and engineering at Lehigh University and, after adjusting to life in America for a year, decided to go out for cross-country in his sophomore year. He struggled even to finish his five-mile tryout. But, in short order, Kosgei was running at the Division I national championships in both cross-country and track. In 2012, he was named Lehigh’s Graduating Scholar-Athlete of the Year.

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As expected from their latitudes of ancestry, though, the Kalenjin and Danish boys did display body type differences. A greater portion of the body length of the Kalenjin boys was composed of legs. The Kalenjin boys were, on average, two inches shorter than the Danish boys, but had legs that were about three quarters of an inch longer.

The scientists’ most unique finding, though, was not the length of the legs, but their girth. The volume and average thickness of the lower legs of the Kalenjin boys was 15 to 17 percent less than in the Danish boys. The finding is substantial because the leg is akin to a pendulum, and the greater the weight at the end of the pendulum, the more energy is required to swing it.

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Compared with the Danish runners, the Kalenjin runners tested by the Danish scientists had nearly a pound less weight in their lower legs. The scientists calculated the energy savings at 8 percent per kilometer.

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Some anthropologists actually refer to the extreme of a slender body build as the Nilotic type — “Nilotic” refers to a set of related ethnic groups residing in the Nile Valley — and, it so happens, the Kalenjin are a Nilotic people.

The Nilotic body type evolved in low latitude environments that are both hot and dry, because the long, thin proportions are better for cooling.

(Conversely, the extreme of the short, stocky build was historically known as the Eskimo type, though the term “Eskimo” has been replaced in some countries, where it is considered derogatory.)

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Anthropologist Vincent Sarich used world cross-country championship results to calculate that Kenyan runners outperformed all other nations by 1,700-fold. Sarich made a statistical projection that about 80 out of every 1 million Kenyan men have world-class running talent, compared with about 1 out of every 20 million men in the rest of the world.

A 1992 Runner’s World article noted, based purely on population percentages, the statistical chances of Kenyan men having won the medals they did at the 1988 Olympics was 1 in 1,600,000,000.

Allen’s rule of body proportions dictates that people from low latitudes and warm climates have long limbs, and Bergmann’s rule dictates that they have narrower builds with slimmer pelvic bones, David Epstein explains (in The Sports Gene), but there’s another, less anatomical reason for western African sprinting dominance:

In 2006, Morrison, with Patrick Cooper, proposed in the West Indian Medical Journal that rampant malaria along the west coast of Africa, from where slaves were taken, led to specific genetic and metabolic alterations beneficial for sprint and power sports. The hypothesis: that malaria in western Africa forced the proliferation of genes that protect against it, and that those genes, which reduce an individual’s ability to make energy aerobically, led to a shift to more fast-twitch muscle fibers, which are less dependent upon oxygen for energy production. Morrison helped with the biology details, but the fundamental idea originally came from Cooper, a writer and childhood friend of Morrison’s.

Cooper was a polymath who had professional success in jobs ranging from music recording to writing speeches for Norman Manley, an architect of Jamaica’s independence, and then for his son, Prime Minister Michael Manley. Early in his career, Cooper had been a reporter for The Gleaner, Jamaica’s largest newspaper. Working at The Gleaner’s sports desk, he first surmised that white athletes had historically dominated sprint and power sports only by systematically excluding or dodging black athletes, like boxing champion Jack Johnson. In later writing, Cooper meticulously documented the fact that athletes with western African heritage become highly overrepresented in sprint and power sports almost immediately once they are allowed a fraction of their white counterparts’ access to sports.

At every Olympics after the U.S. boycott of 1980, every single finalist in the men’s Olympic 100-meters, despite homelands that span from Canada to the Netherlands, Portugal, and Nigeria, has his recent ancestry in sub-Saharan West Africa.

(The same has been true for women at the last two Olympics, and all but one female winner since the U.S.-boycotted 1980 Games has been of recent western African descent.)

And there has not been a white NFL player at cornerback, football’s speediest position, in more than a decade.

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Cooper found the famous body types study of 1968 Olympians, and he latched on to a curious side note recorded by the scientists. The researchers had been surprised to find that “a sizeable number of Negroid Olympic athletes manifested the sickle-cell trait.”

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In 1975, the year after the Mexico City Olympics data was published, another study appeared that Cooper would dissect two decades later, this one showing naturally low hemoglobin levels in African Americans.

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Using data from nearly 30,000 people in ten different states, with ages ranging from the first year to the ninth decade, it reported that African Americans have lower hemoglobin levels at every stage of life than white Americans, even when socioeconomic status and diet are matched.

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Like sickle-cell trait, genetically low hemoglobin — all else being equal — is a genetic disadvantage for endurance sports. Runners of recent western African descent are very much underrepresented at high levels of distance running. (The Jamaican record in the 10K would not even have qualified for the 2012 Olympics)

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And then Cooper found just the potential “compensatory mechanism” he was looking for, in a 1986 study from Laval University in Quebec published in the Journal of Applied Physiology and coauthored by Claude Bouchard, who would go on to become the most influential figure in the field of exercise genetics, and the leader of the HERITAGE Family Study that documented aerobic trainability differences among families.

Bouchard and colleagues took muscle samples from the thighs of two dozen sedentary Laval students, primarily from countries in western Africa, as well as from two dozen sedentary white students, who were identical to the African students in age, height, and weight. The researchers reported that a higher proportion of muscle in the African students was composed of fast-twitch muscle fibers, and a lower proportion was slow-twitch muscle fibers compared with the white students. The African students also had significantly higher activity in the metabolic pathways that rely less on oxygen to create energy and that are engaged during an all-out sprint.

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In his 2003 book, Black Superman: A Cultural and Biological History of the People Who Became the World’s Greatest Athletes, and then in his 2006 paper with Morrison, Cooper first made the argument that West Africans evolved characteristics like a high prevalence of the sickle-cell gene mutation and other gene mutations that cause low hemoglobin for protection from malaria, and that an increase in fast-twitch muscle fibers followed from that, providing more energy production from a pathway that does not rely primarily on oxygen, for people who have reduced capacity to produce energy with oxygen.

The former part of Cooper’s hypothesis — that sickle-cell trait and low hemoglobin are evolutionary adaptations to malaria — now seems undeniable.

In 1954, the same year Sir Roger Bannister broke the four-minute mile, British physician and biochemist Anthony C. Allison, who had been raised on a farm in Kenya, showed that sub-Saharan Africans with sickle-cell trait have far fewer malaria parasites in their blood than inhabitants of the same region who do not have sickle-cell trait.

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Cooper and Morrison’s suggestion that low hemoglobin in African Americans and Afro-Caribbeans is a second adaptation to malaria has been proven true as well, in a deadly manner.

Even as evidence mounted that low hemoglobin levels in Africans native to malarial zones is at least partly genetic, aid workers in Africa looked upon low hemoglobin as a sign purely of a diet with too little iron. In 2001, the United Nations General Assembly charged the world with reducing iron deficiency among children in developing nations. And so, in a well-intended effort to improve nutrition, health-care providers descended on Africa with iron supplements, which raise the hemoglobin levels of those who consume them.

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The problem was that doctors who studied malarial regions saw increased cases of severe malaria wherever iron supplements were dispensed. Since the 1980s, scientists working in Africa and Asia had documented lower rates of malaria death in people with low hemoglobin levels. In 2006, following a large, randomized, placebo-controlled study in Zanzibar that reported a stark increase in malaria illness and death among children given iron supplements, the World Health Organization issued a statement backtracking from the earlier UN position and cautioning health workers about giving iron supplements in areas with high malaria risk. Low hemoglobin, like sickle-cell trait, is apparently protective against malaria.

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About 12 percent of Ivorian citizens are sickle-cell carriers, and in the early 1980s Le Gallais noticed that the top three female Ivorian high jumpers (one of whom won the African championship) became abnormally exhausted during workouts. Le Gallais tested the athletes and found — “surprisingly,” he wrote in an e-mail — “these three athletes were sickle cell trait carriers, despite originating from different ethnic groups in the country.”

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In 1998, he reported that nearly 30 percent of 122 Ivorian national champions in explosive jumping and throwing events were sickle-cell trait carriers, and that they collectively accounted for thirty-seven national records. The top male and female in the group were both sickle-cell carriers.