When David Epstein was a sophomore-year varsity runner at Columbia University, his former training partner, a few years his junior, collapsed and died suddenly during a high school track meet.
"Normally, a fallen runner draws only slight curiosity from a track-savvy crowd," Epstein writes in his new book The Sports Gene. "But Kevin was a state champion, and the dusty, green rubber floor of the track was no place for a state champion to be lying on his back, shuddering." Kevin Richards, it was later discovered, had a genetic disease called hypertrophic cardiomyopathy—the most common cause of natural sudden death among athletes.
As Epstein tried to make sense of Kevin's death, he also became "really, really curious": Were DNA patterns truly so powerful that they could seemingly preordain some athletes for superstardom while they destined his friend for tragedy?
Now a senior writer for Sports Illustrated, Epstein has been investigating the effects of genes on athletic ability ever since. His book examines whether it's genetics or training that most affects who becomes a sports legend and who becomes a recreational player, and closely inspects common, often misconstrued theories about gender, race, and just how many hours it takes to master a craft.
Epstein talked to me recently about why Usain Bolt is so fast, a little-discussed reason so many boxers and football players end up with brain injuries, and why it's dangerous to believe that intellect and athleticism—brains and brawn—are mutually exclusive.
Responses have been edited for clarity and length.
You've written about sports medicine and sports science before. At what point did you say to yourself, "Well, this is becoming a book"?
I started thinking about these things, not quite in genetics terms but in nature-vs.-nurture terms, back when I was in high school. We had a big Jamaican population in my high school, and that made track and field a really popular sport. That phenomenon made me curious. And later, I was running in college at Columbia against a lot of Kenyan guys—who I discovered were largely from the same part of Kenya. And since I would do the same training as the guys I was running with, I would have expected that we would all cross the line in the race at more or less the same time. But it wasn't like that at all: Instead, it would get more and more different. I started to marvel at that, and I got interested in training theology and those things.
Then, my sophomore year of college, my former training partner dropped dead during a track meet. It turned out he had this genetic disease related to sudden cardiac death, and that's what got me into writing about sports science in the first place—wanting to write about sudden cardiac death in athletes.
Your book lays out a lot of heavy-duty science, but what's so effective about it, I think, is that it also puts a memorable, sometimes already-recognizable human face on it. You talked to so many athletes and read up on so much research—which one of these cases you studied taught you the most?
Ooh. The contrast between Donald Thomas and Stefan Holm, the high jumpers, probably—that really stuck with me.
Stefan Holm is this highly dedicated Swedish high jumper who had started inching up year after year after year until he was a world champion and an Olympic gold medalist. I think most people think of jumping as a thing you either have or you don't, but the degree to which he transformed himself, I didn't know was possible. He was this epitome of the "nurture" approach. He had some talent innately, just not as much you'd have thought.
And then to see him get beat by Donald Thomas in 2007, a guy who doesn't even really like the high jump, who had only been doing it for about a year, but who's just got the right genes and the right build to respond incredibly well to training. It just made me realize that there are so many different paths to the same basic physical outcome.
One of the most intriguing things you talk about in The Sports Gene is why it seems like Jamaican runners just seem to be really fast.
So there's a nature and nurture aspect to Jamaica. Early on, I just looked back through pictures of the Olympics and it dawned on me that, in the last couple of years, Jamaicans are ludicrously overrepresented in world-class sprinting—and especially because of Usain Bolt, more people have realized. It's a small country, so to see them dominate world sprinting is just kind of unbelievable.
As I started tracing some of the backgrounds of these athletes, where they were coming from, it was interesting: These athletes of Jamaican descent were coming from many different countries—the Netherlands, Portugal, Nigeria. But their ancestries were always traceable to what's actually a small region of Western Africa, the Bight of Biafra. It has some of the world's highest malaria rates. African Americans and West Africans who are from—or whose ancestors are from the same small area in West Africa where Jamaicans were captured and then taken from in the 17th century, these incredibly high malaria zones—are actually incredibly under-represented in endurance events. These athletes are really over-represented in explosive running, but their national marathon records are awful!
Turns out that West Africans and people of West African descent have low hemoglobin—low levels of this protein that carries oxygen that's really important for endurance running.
For a long time, it was thought to be a nutritional problem: They weren't getting enough iron, some people thought. Some of that was because doctors often looked at basic medical norms that came from white people and compared everyone to those, so that would have implied that if you didn't match that, something was wrong with you. But the fact is, people from malarial regions just have lower hemoglobin. It's a genetic adaptation: People with lower hemoglobin are less likely to get malaria.
There was some evidence, too, to suggest that because they have less capability to produce energy with oxygen, there was a shift in their metabolism, in their forms of energy production. And another part of it is that people with ancestries that predispose them to having long limbs, that's better for running. All other things being equal, having longer legs relatively helps a lot.
But today, I think the particular difference with Jamaicans is this: They have this population that has a lot of talented individuals, but they also have this amazing town sprinting program. It's very much like what we do for college football in the U.S.—we have people who are out of their minds over their local college football team, over their school. Only there it's high-school track.
When I went to the National High School Championships in Jamaica, I started talking to the coaches who were there at the warmup track. I kept asking them about their recruiting. I kept asking, "Well, what do you do? Are you allowed to go meet their parents? Do you talk to the kids?"