The Secret to a Healthy Heart May Lie in the Genes of Elite AthletesCaroline Chen
Elite athletes’ spit may hold the key to better health.
The world’s finest endurance performers are giving saliva samples for DNA analysis to Stanford University researchers, who hope to find new drugs, perfect training methods, and improve exercise and heart health for the merely normal.
At Euan Ashley’s lab in Palo Alto, the director of Stanford’s Center for Inherited Cardiovascular Disease has gathered DNA from 200 world-class runners, skiers and other athletes after hooking them up to a brutal exercise test to separate the best. He plans to eventually sequence DNA from more than a thousand of the world’s fittest people.
“As a cardiologist, I deal with a lot of heart failure,” said Ashley in an interview at Stanford. “I’m interested in the limits of human performance and if the extremely fit groups can help us with the other end.”
Daniel Hansson and Kristin Larsson, a fit, blond Swedish couple, arrived at Stanford’s medical center ready for a workout. They were hooked up to a mask and a treadmill that forced them to run harder and harder while tracking oxygen consumption. The couple competes in adventure and endurance races that can last as long as 7 days with little rest. In 2012, they were the top international competitors in a 40-mile race on the lower slopes of Mount Everest.
Top athletes may have genes that help their hearts pump stronger, their lungs take in more oxygen, or that give them stronger muscles or blood that’s more efficient at transferring oxygen, Ashley said. On the opposite spectrum are people whose hearts are failing, or whose ability to transport oxygen in the blood has weakened by disease. Studying the elite may reveal a pathway for future treatments.
“If the results from this study can help average people increase their health, and learn how to do the right training, if I can help contribute to the health of everyone, I’m happy to do it,” Hansson said in an interview at Stanford.
It’s a strategy that already has at least one real-world success. A rare gene mutation is the basis of a new generation of cholesterol treatments under development by Sanofi, Amgen Inc. and other drugmakers.
The drugs are named after a gene called PCSK9. In normal people, PCSK9 creates a protein that disrupts the ability of liver cells to remove bad cholesterol from the blood. In one aerobics instructor, however, researchers found the she’d inherited a mutation to PCSK9 from both parents, allowing huge amounts of cholesterol to be swept away.
With no PCSK9 protein in her bloodstream, the aerobic instructor’s bad cholesterol levels were between 13 milligrams and 24 milligrams per deciliter. Below 100 is considered good for adults. Drugs based on the mutation are projected by analysts to sell billions of dollars a year.
The cutoff point for athletes to participate in Ashley’s study is high. The researchers are using a fitness measurement called maximal oxygen consumption, or VO2-max, which measures the body’s rate of oxygen consumption based on body weight.
An average healthy, untrained man has a VO2-max of 30 milliliters per kilogram per minute, and a woman’s is normally 25 ml/kg/min. To be in the study, male athletes have to have a VO2-max of more than 75, and women of 63.
In the VO2 test, Larsson, 32, just made the cutoff. Hansson, 37, while quick enough to run the fastest-ever time by a non-Nepalese in the Everest race, barely missed it. Instead, he’ll be studied in a separate group of athletes with lower scores, which the researchers said will need to be included to hit their target of more than 1,000 total people.
Ashley says the cutoff needs to be so high because it is often in outliers that new genetic pathways are discovered.
The researchers also believe the DNA testing may help them discover groups of endurance athletes whose fitness profiles correlate with certain genes. The profiles may help identify what sort of training or exercise may best improve heart health.
“The hypothesis is that the athletes have reached the super-high level with different genetic profiles, but also that they have trained differently to get to the top,” said Carl Mikael Mattsson, a visiting assistant professor at Stanford who is helping to run the study. “Some respond well to a lot of training but others respond better to shorter and harder training.”
Ashley says it’s unlikely that any one gene or even series of genes can predict the next Olympic winner. Any test that claims to predict a gold medal is “a lot of junk science.”
Hansson and Larsson say they’d be interested in any findings that can help them train better, but they don’t care to know about their 8-month-old son’s DNA, no matter his athletic potential. “We don’t want to know before he is 18, then it is his choice,” said Hansson.