Image: Marathon
David Banks  /  Getty Images file
Thousands of runners participate in the Bank of America Chicago Marathon on Oct. 12, 2008, in Chicago, Ill.
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updated 11/1/2008 10:59:37 AM ET 2008-11-01T14:59:37

On the first Monday of November 1994, if you happened to be in Ardmore, Pennsylvania — actually, anywhere near 7 East Athens Avenue — at about 8:30 in the morning, you would have heard the following sound coming from an aging red-brick apartment building.

Thud. Arghh. Thud. Arghh...

Ax murder? Not exactly. No, this was the sad, solitary sound of me, walking down three flights of steps the morning after running the New York City Marathon. As my feet landed on each step, pain spiked into my race-fatigued thighs. By the time I reached the bottom, 48 steps later, I was so exhausted that all I wanted to do was go back to bed.

But that would have required climbing back up three flights of steps. I drove to work and slept at my desk instead.

New York '94 was my third and last marathon. Since then I've downgraded my running efforts to more manageable distances like the half marathon and 10K. Secretly, I've come to wonder if I didn't do damage to myself in each of the marathons I ran. I don't have any scars or permanent injuries (that I know of), but where pain and exhaustion typically fade from memory, my postmarathon distress is as vivid to me now as it was on that horrific morning after.

Which is why it's kind of strange, you'll have to agree, that lately I've found myself wanting to run another one.

Over the course of a generation, the marathon has undergone a startling change in status. What was once a loopy stunt attempted by only a few weirdos is now a rite of passage for many, the coolest test out there of fitness and health.

My buddy McDade actually put running a marathon on his list of "Things a Man Must Do in His Lifetime," right there alongside reading "War and Peace" and seeing the Grateful Dead. (This was before Jerry Garcia croaked.) McDade is hardly alone. Last year, nearly 400,000 runners finished marathons in the United States, up from 300,000 in 2000 and a mere 25,000 in 1976.

On one level, you can file our current marathon mania under "extremely good news," since there's little doubt that training for the race is one of the best ways to improve your health and fitness. Over the years, studies have shown that regular exercise decreases everything from high LDL cholesterol to high blood pressure.

Risks of running a marathon
The problem? Lately, evidence has begun to mount that running the race is, as I've feared, anything but good for your health. Not only did two high-profile marathon deaths occur in fall 2007 (one in Chicago, the other at the Olympic trials in New York), but recent studies have shown that pushing your body to run 26.2 miles can cause at least minor injury to your heart.

"We didn't find any gross injuries, such as blocked arteries or blood leakage. But we did find some enzymes leaking through the heart membrane, which is consistent with significant stress on the heart," says Malissa Wood, M.D., the lead author of a 2006 study in the journal Circulation.

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Now, hardly anyone is suggesting it's time to pull the plug on America's marathon obsession. A handful of deaths versus hundreds of thousands of happy survivors every year aren't horrible odds. (And a new study found that closing roads for marathons prevents more traffic deaths than the running causes.) Even Dr. Wood remains an active marathoner. But if you're one of those with "run a marathon" on a current to-do list (or, like me, on a "maybe-do-again" list), the latest news should definitely give you pause. Could the race you're running as a demonstration of your health and fitness actually make you unhealthy? Or, to put a finer point on it: Could this stunt you're attempting in order to give meaning to your life end your life?

The Chicago marathon and Olympic Trials in 2007 weren't the only races marred by casualties in the past couple of years. There have been several others, including the Little Rock Marathon in March 2008, the London Marathon in 2007, and the Tucson, Twin Cities, and Marine Corps Marathons in 2006. (Also in 2006, two runners died at the Los Angeles Marathon.) And that's not counting the races during which runners suffered cardiac arrest but managed to survive.

Any historian of running will tell you there's nothing new about death and the marathon. Legend has it, remember, that the original marathoner, Pheidippides — the Greek courier who ran 25 miles to deliver news of victory at the Battle of Marathon — dropped dead immediately after his job was done. At the inaugural Boston Marathon in 1897, authorities were so concerned about fatalities that they had two attendants on bicycles trailing closely behind each of the runners — all 15 of them.

The body's reaction
It's a risk that has persisted through the decades. "There was actually a cardiac arrest at one of the first Boston Marathons I ran, in the 1970s," says Arthur Siege, M.D., director of internal medicine at Harvard's McLean Hospital in Belmont, Massachusetts. In addition to running the Boston race some 20 times, Dr. Siege has published many studies on the health consequences of marathons. It's late on a Tuesday afternoon, and I've come to visit him (He's an engaging man in his late 60s with white hair and a round belly) for one simple reason: to understand what exactly happens to a man's body when he forces it to run 26.2 miles.

Researchers have identified a number of physical effects of running a marathon, including changes in immune system and kidney function. But Dr. Siege says the brunt of the damage falls exactly where you'd expect: on your muscles. As the miles pass, skeletal muscles stiffen and leak injury-signaling enzymes into the blood.

Now, a certain inability to (ahem) walk down steps the next day notwithstanding, this may not seem like such a big deal, particularly given that the damage is self-inflicted. But your body's internal balance is deeply affected. As Dr. Siege puts it, "Your body doesn't know whether you've run a marathon... or been hit by a truck." This is why, as you go deeper into the race, your body reacts to injury by mounting an emergency-repair response. Your adrenal glands and brain produce the stress hormones cortisol and vasopressin; your damaged muscles churn out proteins called cytokines, which trigger your liver to start producing C-reactive protein.

The result is what Dr. Siege calls "an inflammatory storm" throughout your body, one that sets the stage for some potentially adverse consequences. Early on, marathon researchers weren't sure if the heart was among the muscles being stressed, but in recent years they've confirmed that it most definitely is. In a 2001 study published in the American Journal of Cardiology, Dr. Siege and his colleagues analyzed the blood of marathoners less than 24 hours after a race and found high levels of inflammatory and coagulation markers that are also associated with heart attacks.

Then came the 2006 Circulation study, led by Dr. Wood, which upped the ante. Using ultrasounds and blood tests of 60 marathon finishers, the researchers found that after the race, some runners' hearts experienced difficulty refilling chambers. The researchers also noticed abnormalities in how blood was pumped from the right side of the heart to the lungs.

Benefits of proper training
Before you go into full freak-out mode, there is some good news. First, proper training seems to go a long way toward protecting you from heart injury during the race. The Circulation study found that people who'd averaged at least 45 miles a week in training were significantly less likely to suffer heart damage than those who ran 35 miles a week or less. That makes sense to Dr. Siege, who notes that training is an injury-and-repair process: Your body suffers damage when you exert yourself during training but then repairs itself and becomes stronger. So runners who log lots of training miles are able to withstand more punishment during the race than those who train less.

The other piece of good news is that even among marathoners who were undertrained, heart damage didn't appear to be permanent. Within a month, all the runners in the study showed relatively normal cardiac function. "There is no data to suggest that any long-term aftereffects were caused by the changes," says Dr. Wood.

But blocking out that dose of sunshine is still a very dark cloud: During the race and for several hours afterward, the systemic inflammation significantly increases your risk of a cardiac event, particularly if you're middle-aged and have some silent coronary-artery disease. (Men in their 40s and 50s form the biggest cluster of marathon fatalities.) Two things happen: First, inflammatory mediators released during muscle injury may make the thin, fibrous plaque that lines your artery walls more likely to rupture; second, this inflammation can lead to an imbalance of coagulation factors, making blood more susceptible to clots. The result: a heart attack.

The paradox is that marathoners' training puts them at an overall lower risk of heart trouble. But when you start doing the event for which you've been training, your relative risk increases. To oversimplify: At the starting line, you're Lance Armstrong; at the finish line, you're Louie Anderson.

"Marathon running may be regarded as a dose of exercise that pushes you past the zone of cardioprotective benefit into one of enhanced risk," says Dr. Siege, who stopped running marathons more than a decade ago, partly because of the risks involved. If you want to be smart, he suggests, do all the training for a marathon... and then watch the race from the sidelines.

But, well, what fun is that, right?

A sense of accomplishment
The reason most people suffer through all those dreary training miles is for the thrill of the race. Take away that carrot, and many marathoners would be on the couch munching Pringles and watching "American Gladiators." Eliminate the risk and you inadvertently eliminate an incentive.

My motivations: I liked to run. I knew I'd be in kick-ass shape. And my buddy McDade was doing it, so I felt some camaraderie and competition. As it turns out, I'm pretty typical. A study of motivation in the Journal of Sport Behavior found that most runners have multiple reasons for participating in the sport, from improving their health to socializing to competing. "People might have started with one motivation — say, becoming fit — but when they got into it, they found all these other side benefits," says one of the study authors, Ohio University psychologist Benjamin Ogles, Ph.D.

While women were most likely to cite weight control and socializing as reasons for running marathons, men were more into achievement and competition, either with themselves or others. It is, I suppose, easy to mock this as typical lunkheaded guy behavior: Me tough guy. Me run marathon. But Ogles says there are definite mental health benefits to setting and meeting a challenge.

"Running a marathon brings a great sense of accomplishment," he says. Citing research that dates back decades, he adds, "This need for us to have success at things can be a strong motivational force. Even young kids can be motivated by successful mastery of basic skills — [researchers] talk about the gratification that comes from learning how to walk." Mastering a skill is crucial, he says: "When there are problems with self-mastery, you end up with problems like depression."

To put it another way, we seem to have an innate need to do things simply for the sake of doing them or to see if we can do them. What makes me and half a million other people want to run a marathon, even though we know it might not be good for us? Maybe it's the same things that drive people to climb Mt. Everest or drove Leo Tolstoy to write a 1,400-page epic about Russia in the time of the Napoleonic wars.

Because it's there. Because we can.

Which brings us back to the dilemma at hand: Is the satisfaction that comes from running a marathon worth the risk?

Dr. Siege hopes that studies may someday show that "drugs that undermine inflammation, such as aspirin or statins, may protect runners during the transition from low to high risk during and after races." In the meantime, if you're planning to run a marathon, you should have some respect for what you're getting yourself into. That means training properly — a minimum of 45 miles a week. It also means understanding that there is some risk involved.

"People choose all the time to do risky things, like mountain climbing and scuba diving," says Dr. Siege. "Thrill seekers are well advised to understand the risks involved to limit any adverse consequences. Marathon running is potentially dangerous for susceptible individuals. Pheidippides is still out there."

Well, actually, he isn't. He's dead. And that's a message I'm going to remember as I lace up my running shoes and start training for an event that, for some reason, I just can't seem to resist.

© 2012 Rodale Inc. All rights reserved.

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