The Sports Gene: Inside the Science of Extraordinary Athletic Performance

Epstein opens Chapter 15 with a heartfelt personal story about a high school friend, Kevin Richards, who died suddenly while crossing the finish line after a race. Richards had, unbeknownst to him, a genetic disease called hypertrophic cardiomyopathy (HCM) that caused his heart to fail and that “is the most common cause of sudden death in young athletes” (245). As of 2002, “18 different genes and 1,452 different mutations” have been identified as causes of HCM (247). People who suspect a mutation runs in their family can get tested; athletes, too, can opt to test themselves (but the Genetic Information Nondiscrimination Act passed by Congress in 2008 makes it illegal for employers to demand genetic information). Doctors who test for HCM mutations face the dilemma of clearing young athletes for participation in sports.

Epstein wonders, “What if the athlete was just at risk of damage? Sports are inherently risky […] what if scientists could tell that some athletes are at greater risk than others?” (252). Epstein launches this inquiry into risk factors by examining the ApoE gene, which is involved in brain health and memory. The ApoE4 variant of the gene appears to influence Alzheimer’s, dementia, and the ability to recover from head trauma. This gene is relevant to athletes in sports like hockey and football in which head injury is common, as an ApoE4 variant combined with a career in a rigorous contact sport means compounded danger. Epstein surveys opinions about whether individual athletes would want, or not want, to get tested for the ApoE4 gene, especially when “there is no proven remedy for delaying the onset of Alzheimer’s” (257). Athletes can also test for mutations in the genes that influence collagen, some of which make a person more prone to tendon and ligament injury.

Finally, Epstein discusses how genes influence pain perception. Some gene mutations block pain perception entirely; others influence how sensitive or tolerant a person is to pain. Furthermore, “genes involved in emotion might alter pain sensation” (262). The brain can also mute pain signals in moments of fight-or-flight—this is meant as a survival mechanism, but it’s also activated in games and competitions, causing some athletes to literally not feel pain until the game is over. Still, one study of dogs that were completely isolated and didn’t process pain revealed that pain must be learned. Epstein closes the chapter wondering if it’s useful to seek out an “athlete gene” considering that genetics and environment are so “intertwined as to become a single vine” (265).

Epstein travels to the far north of Finland to meet Olympic cross-country skier Eero Mäntyranta and his family. In addition to a colorful description of his trip and his personal impressions of Mäntyranta, Epstein details Mäntyranta’s biography, which began in rural poverty. Mäntyranta developed focus as a way to block out the stimulus in a crowded household. As a child, he skated across a frozen lake and cross-country skied to school. He evacuated Finland with his family during World War II and, as a young man, trained to join the Finnish Olympic team as a means to a job as a border patrol guard. He went on to race in four Olympics, win seven medals, and place in 500 races in his career.

Mäntyranta has a genetic disorder that causes him to have “extraordinarily high levels of hemoglobin, the oxygen-carrying protein in red blood cells” (274). Rumors of doping circulated during Mäntyranta’s career, but a genetic test revealed that a “minuscule alteration” in “position 6,002” of one EPOR gene (the gene that tells the body how to build a hormone receptor on bone marrow cells, which produce red blood cells) caused Mäntyranta to have a massively high amount of hemoglobin. This genetic mutation came with no consequences to his health and constituted a huge advantage in the endurance sport that he entered merely to get a better job, but for which he became world-famous.

Epstein catalogues the results of genetic testing done on Mäntyranta’s extended family, looking for other carriers of the gene and other great skiers. He interviews Mäntyranta, who believes it was his mind and not his body that led him to athletic glory, but experts in the science of his genes disagree.

Epstein opens the Epilogue by re-examining the case of Eero Mäntyranta and the way that nature and nurture interplayed in his extraordinary athletic success. Certainly he had a genetic gift, which Chapter 16 explored in detail, but Epstein emphasizes that “he needed to train assiduously to alchemize that talent into Olympic gold” (282). The fact of innate talent and genetic advantage does not detract, Epstein believes, from an athlete’s hard work. Using Michael Jordan as an example, Epstein argues that his “obvious gift of height” does nothing to lessen the awe-worthiness of his achievements (283).

As for the challenges presented by future genetic research in sports, Epstein says:

It is increasing clear that many traits are influenced by the interplay of large numbers of DNA variations. Thus, studies will require hundreds or even thousands of subjects to get at the genetic root of such traits. But there aren’t thousands of elite 100-meter runners in the world. Additionally, the gene variants that make one sprinter fast may be completely distinct from those that make her competitor in the next lane fast (285).

In identifying 23 genes that influence endurance, researchers have made statistical projections that show that a “perfect” endurance athlete is unlikely to exist in the entire global population. Instead, “essentially everybody falls in or near the muddled middle, differing by only a handful of genes” (287). Even children born of two athlete parents are less likely to “get as lucky as a very lucky parent” with traits that require the interplay of more than one gene (288).

Epstein closes by voicing an appreciation for the beauty of the genetic diversity on the planet and for the way sports acts as a showcase for that diversity. He emphasizes that different bodies benefit from different training, but all people benefit in some way from exercise. Thus, he signs off with an encouragement to his reader to participate in exercise or sports, saying, “Happy training.”