On March 31, 2012, ultramarathon runner Micah True—nicknamed “White Horse”—was found dead in the wilderness of southwestern New Mexico. He had left days earlier on a 12-mile run. His body was discovered on the banks of a small stream.
An autopsy found the left side of the 58-year-old man’s heart to be enlarged and scarred. The state’s Office of the Medical Investigator concluded True had idiopathic cardiomyopathy—heart disease of an unknown cause—but the changes suggested True may have suffered heart damage caused by chronic excessive endurance exercise.
Now, a new study by the Mayo Clinic suggests that exercise like marathons and triathlons can cause major damage to a person’s heart. We’ve been told that exercise is good for us, and marathons, in particular, are especially popular in America right now. Is it time to change our thinking?
Benefits of Marathon Running?
According to Stride Nation, the marathon is more popular than ever. Over the past 12 years, there’s been a 47 percent increase in the number of marathon finishers in U.S. races. Approximately 518,000 people finished more than 720 marathons in the U.S. in 2011.
Yet while there are more runners, there are also more deaths. In 2009, four runners died during half-marathons in San Jose, California, and Detroit. In 2011, two runners died at the Philadelphia Marathon, all from apparent sudden heart attacks. And many of us know the tragic story of Jim Fixx, author of The Complete Book of Running and the nation’s leading spokesperson for the health benefits of running, who died tragically of a massive heart attack while running alone on a country road. He was only 52 years old.
What are the benefits of marathon running? A lot of people start training for them with specific goals in mind. Many want to lose weight. Some want to jump-start their exercise programs, and need a specific goal. Many believe it will be good for their health, and win them stronger hearts, leaner bodies, and deeper nights of sleep.
Yet according to the Wall Street Journal, “There’s no evidence that running a marathon leads to lasting weight loss.” In fact, since people tend to eat more during training, and then maintain the calorie-count after the race—but take a break on the running—many actually gain weight after the race is over.
Neither do marathons lead to new exercise habits. In fact, many won’t continue with the running lifestyle because of waning interest, busy schedules, and injuries. “If the marathon movement really got people at large to exercise,” said Steven Blair, professor of public health and University of South Carolina, “we wouldn’t have the problems we do” as a too-sedentary nation.
What the Study Found
Researchers from the Mayo Clinic reviewed the results of over 50 studies published between 1991 and 2012 on the health effects of extreme endurance training and competition. They found that more than an hour of intense aerobic activity per day put runners and cyclers at heightened risk of serious heart problems, including an irregular heartbeat, clogged arteries, and scarring.
Habitual marathon runners and professional cyclists, they noted, were five times more likely to have irregular heartbeats than their less-active peers. Researchers theorized that repeated structural changes to the heart occur during excessive endurance training or competition, and when people take part in these activities multiple times over several years, scar tissue can form and weaken the heart muscle.
In fact, exercise more than an hour, and you experience “diminishing returns,” according to lead author James H. O’Keefe.
How to Keep it Healthy
Of course, this study doesn’t apply to most people who aren’t engaged in regular intensive athletic training. For the majority of Americans, more exercise is in order—not less. The key here is moderate, regular exercise, without extreme durations or intensities. In fact, other studies have shown that running at moderate speeds is linked with a lower risk of death from any cause compared to not running at all.
The message is not to fear exercise, O’Keefe said, but to practice moderation. But if you are engaged in regular running or cycling, how can you tell if you may be at risk?
According to a 15-year observational study of 52,000 adults, the highest degree of survival and health was found for those that:
- Ran less than 20 miles a week
- Ran at speeds of six to seven miles an hour (about a 10-minute mile)
- Ran 2-5 days a week
Those who ran more than this at faster paces had no additional survival benefits.
Other signs that you may be doing more than your body can handle include tendinitis, stress fractures, and other overuse issues. If you’re suffering from any of these, cut back on your miles.
As to how many marathons per year to run, researchers aren’t sure. Where the damage starts to occur depends on the person. Aiming to run three in one year may be too much—O’Keefe suggests against it. One a year may be fine. In fact, a 2010 study in the New England Journal of Medicine noted that the rate of deaths in marathons continues to be very low, between one in every 100,000 and one in every 200,000.
Finishing even just one marathon, however, is associated with temporary damage to a runner’s body. Research shows that 30¬–50 percent of runners showed increased levels of enzymes and biomarkers typically released during heart attacks and associated with heart failure. Usually these go away within a month after the race.
As you’re setting your fitness goals, realize that most likely, marathons, triathlons, and cycling races won’t make you healthier, and may even cause some health damage.
I love the idea of running for hours in the woods. I used to do it.
I’ve run a few trail marathons and a few more road marathons. These days, not as much. It’s not that I don’t like to run as much, or that I’m scared of not being as healthy as I can — it’s just because I don’t have as much time.
The story of Caballo Blanco (Micah True) in “Born to Run” was intriguing and mysterious and his legacy will “ride” for much longer in long distance and ultra-running circles.
But, yes, it’s important to stress that too much of anything, can be too much.
One of my mentors from afar — that I was finally able to meet — Dr. Phil Maffetone has been teaching long distance and endurance athletes to chill out for years. What happened when they did?
Their performance improved.
Maybe this is just the clue that’s needed to keep your exercise routine in balance and your body healthy and happy for many decades to come.
I can’t say I’m done with marathons, but I am done with training more than 25-30 miles a week — for me there’s just not enough time in the week to make that a priority and based on the evidence here (which I already suspected), I probably will be healthier doing other things — like hanging out with family, the new baby, or friends.
Do you run marathons? What do you think of this study?
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Photo courtesy joshhikes via Flickr.com.
Zelie Pollon, “Ultramarathon Runner Micah True Died from Heart Disease: Autopsy,” Reuters, May 8, 2012, http://www.reuters.com/article/2012/05/08/us-usa-marathon-autopsy-idUSBRE8471HR20120508.
Kleph, “The Marathon—More Popular Than Ever,” Stride Nation, February 28, 2012, http://www.stridenation.com/2012/2/28/2830407/the-marathon-more-popular-than-ever.
Kevin Helliker, “The Fleeting Benefits of Marathons,” Wall Street Journal, October 6, 2009, http://online.wsj.com/article/SB10001424052748704252004574455331050172834.html.
Kathleen Doheny, “Can Too Much Exercise Be Harmful?” WebMD, June 4, 2012, http://www.webmd.com/fitness-exercise/news/20120604/can-too-much-exercise-be-harmful.
John Robbins, “What Should We Learn from the Deaths of Fitness Icons,” February 10, 2011, http://www.johnrobbins.info/blog/what-should-we-learn-from-the-deaths-of-fitness-icons/.
Christine S. Moyer, “Too Much Endurance Running, Cycling Might Weaken the Heart,” American Medical Association, June 18, 2012, http://www.ama-assn.org/amednews/2012/06/18/hlsa0618.htm.
Kelly O’Mara, “How Much Running is Bad for Your Heart?” Running Competitor, June 2012, http://running.competitor.com/2012/06/news/how-much-running-is-bad-for-your-heart_54331.