Posted by Dave on June 24, 2011 | 4 CommentsJim Fixx was an overnight sensation as a recreational runner who had worked himself into shape and written a book about the health benefits of running. But when he died of a heart attack shortly after a run at age
Even so, a quarter-century after Fixx’s death, the relationship between running and heart disease remains difficult to decipher. There is little doubt that moderate exercise paired with other healthy habits can do a lot to stave off heart disease and myriad other health problems. But what about extreme exercise? As hundreds of thousands of runners go beyond merely jogging and enter in ever-greater numbers into exhausting half-marathons, full marathons, and even ultramarathons, could this seemingly benign hobby actually be harmful?
I’ve been a runner all my life, but like many people my age (44), I’ve recently become much more intense runner, building over two years from 15 miles or so in a typical week up to nearly 70 some weeks. I’ve run my first two marathons, and I’m planning on running more. In my marathons, I’ve approached total exhaustion, unable to pull myself up from the ground after sitting down to rest in the finish area. Could this kind of abuse be detrimental to my long-term health?
I’m going to write a couple of posts on this topic, so I can’t give a full answer just yet, but I thought I’d start by discussing an intriguing 2009 study led by Frank Breuckmann. The team of German researchers recruited 102 male marathoners age 50 or older who had run at least five marathons. They matched them with a control group of non-runners with a similar age profile, who didn’t participate in endurance sports. Neither group had a history of heart disease.
However, in this case the LGE of only five of those runners was the type that predicts heart disease. This, it turns out, was not a statistically significant result. In other words, scientifically, we can’t say anything about the LGE levels in marathoners versus non-runners.
But the researchers also followed up with both groups for nearly two years to see if one group actually had more heart attacks and other “cardiac events.” Here, the results were significant: Three runners experienced cardiac events, compared to just one non-runner.
Does this mean that marathoning causes heart attacks? While the results of this study are shocking, it’s not reasonable to jump directly to that conclusion. One possible explanation for the non-significant but higher incidence of LGE in the runners is that running actually delays the onset of heart disease. Remember, people who’ve had heart attacks were excluded from the study; it could be that in the control population, men who were likely to have heart attacks would have already had them. In this scenario, being a marathoner, far from hurting you, can actually help defer heart attacks. It’s also possible that while running is generally beneficial, it might be harmful in cases where there are other indicators of heart disease like smoking or a family history. Indeed, over 50 percent of the marathoners in the study were former smokers, so that could have had a big influence on the results.
What does this mean for you?
If you’re a man over 40 and you have other risk factors for heart disease, this study suggests you might want to get a thorough heart-health evaluation if you run or plan to run significant distances (like marathons, or heavy training upwards of 40 miles a week). Of course, if you’re already at risk for heart disease, this sort of evaluation wouldn’t be a bad idea in any case. If you run less than that, this research probably doesn’t apply to you at all, and other research suggests moderate exercise almost certainly is good for you. Either way, the study is too small to show a genuine risk from marathon running. This study on its own isn’t enough to make the claim that people shouldn’t be running marathons—and of course it doesn’t apply to women at all!