3 Myths—and 1 Truth—About Running and Your Health

Every person who takes up running has, at one time or another, been confronted by a helpful critic who is more than happy to reel off the reasons running will ruin your life. It will cripple you in your later years; you might drop dead in the middle of a marathon; and on and on. As an avid runner, I have a lot riding on whether or not these ideas about the sport are true. Here is a look at four questionable claims about running and health, including results from a new study looking at running, longevity, and disability.

1. Running will give you a heart attack or other heart problems. It is true that exercise temporarily raises the odds of a heart attack while you're mid-workout, but doing it consistently reduces that risk over the long haul, leading to a net benefit. Some researchers have questioned whether marathon running, especially in people who haven't trained a lot, might cause heart damage, at least temporarily. But there's no evidence that it causes long-term harm or actually leads to heart attacks. Even athletes with enlarged hearts—if they're healthy hearts—aren't, as once feared, at risk of early death. The bottom line: Simply going for a run most days of the week is doing far more good than bad for your heart.

2. Running will ruin your bones and joints. A study in the August issue of the American Journal of Preventive Medicine found no evidence of accelerated rates of osteoarthritis among long-distance runners when compared with healthy nonrunners. "We used to say that osteoarthritis came from wear and tear. That's now revised to say that is can result from tear but not wear," says James Fries, emeritus professor of medicine at the Stanford University School of Medicine and senior author of the study. Moreover, weight-bearing exercise like running helps stave off osteoporosis by maintaining bone mineral density.

3. Running can increase your odds of skin cancer. This one appears to be true: A 2006 study found that white marathon runners had more abnormal moles and lesions than nonrunners and were at a higher risk of both melanoma and nonmelanoma skin cancer. (Marathoner Deena Kastor, representing the United States in the Olympics, has had skin cancers removed.) The more miles run per week, the more likely a runner in the study was to be referred for surgical treatment, suggesting the length of sun exposure is a factor. The solutions: Wear sunscreen, no matter what time of day you run. (Only 56 percent of the runners in the study used sunscreen.) Don't run when the sun is strongest—go early in the morning or later in the afternoon or evening. And cover up if you can, by wearing a hat and protecting as much of your skin with clothing as you can stand. (For information on how to spot skin cancer before it becomes deadly, see this guide by my colleague Adam Voiland.)

4. Running will kill you before your time. According to a study published this week in the Archives of Internal Medicine, running and other vigorous exercise in middle age is associated with a longer life. Not only that, it will make your later years more pleasant by reducing disability. After tracking runners and healthy nonrunners for 21 years, starting when they were at least 50 years old, a research team led by Stanford's Fries found that the ability to perform activities of daily life like getting out of a chair and walking was better among runners than nonrunners. And 19 years into the study, 15 percent of the runners had died, compared with 34 percent of the nonrunners.