Are Marathons Dangerous?

Special Report: Are Marathons Dangerous?



If running is so good for you, why do people drop dead during marathons every year? A lifelong runner, with help from the experts, finds the encouraging truth behind the scary headlines.


By Amby Burfoot


Image by Matt Mahurin


Grave Concerns


Special Report: Are Marathons Dangerous?


If running is so good for you, why do people drop dead during marathons every year? A lifelong runner, with help from the experts, finds the encouraging truth behind the scary headlines.


By Amby Burfoot


Image by Matt Mahurin


From the December 2008 issue of Runner's World


The Running Effect


"I feel a little awkward about meeting John Fixx," says heart specialist Paul Thompson, M.D. "His father made me famous." It's a gray, drizzly afternoon three days after my run with Steve Blair. Thompson and I are jogging from Hartford Hospital, where he's chief of cardiology, toward nearby Colt Park. I've arranged for Fixx, an old friend, to meet us there for a five-mile run.


A month earlier, Thompson, 61, had finished the Boston Marathon in 3:24:01. He's slight-5'7" and 144 pounds-with a boyish face, a forehead that goes on forever, and a respectful manner. Thompson completed his first Boston 40 years earlier, in 1968 (34th place, 2:49:22), while still a Tufts University undergrad. Several years later, he improved his Boston best to 2:28:25, his PR. He ran 14 straight Bostons, but a move to Pittsburgh, four kids, and increasing hospital responsibilities will put a dent in anyone's schedule. More recently, with the kids grown and a move to Hartford, he's run the last nine Bostons.


By the time of Jim Fixx's death at age 52 in 1984, Thompson had graduated from medical school, done some advanced studies at Stanford, and published two papers on heart-attack deaths in runners. That made him the go-to expert for hundreds of TV, radio, and newspaper reporters chasing down the Fixx story. Over the years, Thompson has remained everyone's favorite expert for insights on exercise and heart disease. He has also worked as a TV commentator at the Seoul Olympics and the New York City Marathon, and his name turns up frequently in publications like The New England Journal of Medicine.


Thompson has had a lifelong fascination with the workings of the heart, in particular its response to exercise. "Sometimes I wish I could read heart studies all day long instead of attending to administration details," he says. "Think about the overweight guy who's totally out of shape until he begins exercising. A couple of months later, he's a different person. The heart is so amazing, and so damned good at what it does."


Thompson runs with the quick, light stride of the veteran marathoner, and has already covered eight miles in the early morning. "It's the one time of day I get to focus on myself," he says. "This makes me a much better person when I get to work and have to focus on staff and patients."


I ask Thompson why some runners keel over and die from heart attacks. He explains, first, that the young ones, mostly under 30 or 35, generally have structural defects in their hearts, such as the heart scarring that apparently led to Ryan Shay's death. These include a bewildering variety of rare conditions, and one-hypertrophic cardiomyopathy-that gets mentioned much more than the others for two reasons. First, it's the most common cause of sudden heart death in young athletes. Second, it results from an enlarged heart. This leads to widespread confusion, because endurance athletes like marathoners also have enlarged hearts. But the two are completely different. The marathoner's heart is large, healthy, and efficient; it's like a car that gets 40 miles per gallon. The hypertrophic cardiomyopathy heart is misshapen, malfunctioning, and dangerous; it results from a physical defect, not from hard endurance training.


When an over-35 exerciser dies on the run, Thompson continues, the cause is almost always artery disease-that is, cholesterol deposits that rupture and provoke a heart attack. He describes it like this: Imagine a garden hose with a modest flow of water moving through it. That's your arteries when you're resting. When you begin to run faster, the flow of blood increases dramatically. The hose begins to twist and flail. You've felt this with your own hose, or noticed how firemen must brace themselves to control a high-pressure hose. "So your arteries are flexing and bending," says Thompson. "Now if you've got a cholesterol deposit in the artery, the movement can crack the deposit open. Your blood mixes with the cholesterol to form a clot that blocks the artery. A few minutes later, you've bought the farm."


In Thompson's classic 1982 study of runners' heart-attack deaths in the state of Rhode Island, he found that a runner's relative risk of dying during a workout was about seven times that of dying in front of the TV. It amounted to one death for every 396,000 hours of running, almost exactly the same rate found decades later in several marathon studies (see "Risk of Death While Marathoning," page 98). This doesn't mean that running caused the deaths. It would be more accurate to say that artery disease caused the deaths, and running was merely the trigger. Here's why: Another Rhode Island study showed that the blizzard of February 1978 touched off a mini-epidemic of snow-shoveling deaths. A week later, however, heart-attack deaths dropped below normal levels. In other words, after all the people with advanced artery disease had died, there were few diseased hearts left.


Like other heart experts, Thompson notes that regular exercise offers no sure protection from heart disease. Three hundred and twenty-five thousand Americans suffer an outside-a-hospital heart attack every year, often without warning, and 40 percent of these events end in sudden death. "Exercise is not a savior," Thompson says. "The risks are very low, the benefits are real, and the benefits outweigh the risks. But there are no guarantees. Regular exercise is like investing in the stock market. You hope that your stock will improve over time, but every once in a while you catch a Bear Stearns."


This can happen even to fit runners with low cholesterol who've passed a stress test in the last 48 hours. Still, the occasional exercise death doesn't change the advice for healthy living. "If you want to live a long, vigorous life, you should do an hour of moderate exercise a day," says Thompson. "If your only goal is to survive the next hour of your life, you should get into bed-alone."