Death by exercise

Reposted from Men’s Health:  Hundreds of guys — including some of the world’s fittest men — have taken their final breaths while wearing running shoes. Here’s how to outsmart the reaper –

Guy goes out for a run. It’s just a 4-miler–nothing, really, to a seasoned marathoner who usually runs 10 miles a day, 7 days a week. Nobody knows why he stops 40 or 50 yards short of his front door–maybe he’s checking his pulse, maybe he’s tying a shoe–but everybody knows what happens next to Jim Fixx, the 52-year-old patron saint of running: He dies.

You’ve heard that story. But you may not know about Edmund Burke, Ph.D., who was to serious endurance cycling what Fixx was to running. He died on a training ride last fall, at age 53.

And you almost certainly haven’t heard of Frederick Montz, David Nagey, or Jeffrey Williams, three brilliant physicians at Johns Hopkins University who died while running. The oldest of the three was 51.

You’d think that exercise icons should live to be 100. And yet, every year, a few of them go permanently offline at half that age.

Two questions arise. The first is obvious: Why do the hearts of such highly conditioned men fail during exercise designed to make their hearts stronger? The second is so radical it borders on treason against the health and fitness cause: Is there something wrong with the entire notion of endurance exercise as a healthy, life-extending activity?

I’ve been skeptical about the benefits of aerobic exercise for years. But the answers surprised even me. Pull up a chair–you’ll want to be sitting down when you read this.

The Road to Nowhere

The idea that a well-trained endurance athlete could just drop dead was unfathomable a generation ago. Thomas Bassler, M.D., went so far as to say that anyone who could finish a marathon in less than 4 hours could not have serious heart problems. He conducted a study on 14 marathoners who had died of cardiovascular disease, and concluded that all were malnourished. Unfortunately, he reported this conclusion in the July 27, 1984, edition of the Journal of the American Medical Association. Fixx had died 7 days earlier.

Nobody today believes that endurance training confers immunity to anything, whether it’s sudden death from heart disease or the heartbreak of psoriasis. Every time you lace up your running shoes, there’s a chance your final kick will involve a bucket, and every expert knows this.

“I think the risk is inescapable, and it’s bigger than we’re letting on,” says Paul Thompson, M.D., director of preventive cardiology at Hartford Hospital in Connecticut and a researcher who studies sudden death and exercise. One of Dr. Thompson’s studies showed that 10 percent of the heart attacks treated at his hospital were exercise related. “Those heart attacks tend to be in people who aren’t fit,” he says. “But that doesn’t mean that’s the only group that gets it, unfortunately. There are these very fit guys who go out for a run and drop dead.”

Dr. Thompson’s studies and others show that the chances of sudden death are about one in every 15,000 to 18,000 exercisers per year. That comes to one death for every 1.5 million exercise bouts. Curiously, the most serious endurance athletes seem to be at the greatest risk. Here’s how it breaks down, according to an often-cited 1982 study published in the New England Journal of Medicine: <* />

One death per 17,000 men who exercise vigorously 1 to 19 minutes a week

One death per 23,000 men who exercise vigorously 20 to 139 minutes a week

One death per 13,000 men who exercise vigorously 140 or more minutes a week

I had to look at the chart twice to see its startling conclusion: The highest death rate is among the men who exercise long and hard, and is much higher than that of the men who exercise short and hard. Worse, the guys who do hardly any vigorous exercise had a lower death rate than the guys who do the most.

About a zillion studies — I lost count in the millions — have shown that aerobic exercise leads to a healthier heart and a longer life.

So I have to wonder why more of such a healthy activity is worse, rather than better.

Sweatin’ to the Oldies

In 1970, a study of San Francisco longshoremen made a strong argument that physical activity helps prevent heart disease. The longshoremen who got promoted to mostly sedentary management positions developed heart disease 25 percent more often than those who worked on their feet.

An important note about this study, and similar ones that preceded it: The subjects weren’t doing formal, steady-pace endurance exercise. They were walking and stopping, lifting things up and putting them down.

Numerous formal exercise studies followed, many of them attempting to quantify how much physical activity is needed to prevent heart disease, and at what intensity levels. The Harvard Alumni Health Study found that heart-disease risk starts going down when you expend more than 500 calories a week and continues to decrease until you get to 2,000 calories a week. Then things level off–more exercise doesn’t offer more protection.

The bottom number isn’t much exercise; a 200-pound man walking 2 hours a week at 3 mph will burn 600 calories. And the top number isn’t particularly intimidating, either. Our 200-pounder would have to run about 16  miles at a 12-minute-mile pace to burn 2,000 calories a week. (Lighter guys will burn fewer calories per minute or mile; bigger men will burn more.)

Intensity is a separate issue, with some studies showing that moderate-intensity exercise (walking, bowling, playing golf) helps your heart, and others showing little benefit until you start cranking (running, lifting serious iron, playing basketball or soccer).

Still other studies measure heart-disease risk by activity level, and these show something really interesting: Once you get past the 75th percentile of physical activity–guys who exercise more than three-quarters of the population–protection against heart disease levels off. In fact, among the most active, it actually declines slightly, according to a review in Medicine & Science in Sports & Exercise. In other words, the superactive are more likely to die than the merely active.

Snow Problem

One reason it’s so hard to understand the whole death-by-exercise phenomenon is that so few people die during formal exercise–there are only about 100 cases per year. So it helps to look at those who suffer heart attacks during heavy physical exertion in general, rather than fitness activities in particular. One important study, published in the New England Journal of Medicine in 1993, looked at 1,228 nonfatal heart attacks, 54 of which occurred during or soon after serious exertion. (The cutoff point was 6 metabolic units, or METs. This means the exertion was greater than or equal to six times the energy required by a body at rest. Heavy strength training is considered a 6-MET activity, as are wood chopping and snow shoveling; running 12-minute miles racks up 8 METs.)

The researchers divided the cases into three categories and found that about 18 percent of the exercise-induced heart attacks occurred during lifting and pushing, 30 percent during jogging or sports (racquet sports in particular), and 52 percent during yard work, such as splitting wood.

And that brings us to a major cause of death by exertion: snow shoveling.

A researcher at William Beaumont Hospital in Royal Oak, Michigan, tallied 36 snow-related deaths in the Detroit area following two heavy storms. (Curiously, several of the victims were using snowblowers.)

It’s easy to see why frozen precipitation scores such a high body count. “Heart rates go up like a maximal treadmill test,” says Barry Franklin, Ph.D., director of cardiac rehabilitation and exercise laboratories at the Beaumont hospital. “Combine that with cold weather, which constricts arteries, and you have a prescription for disaster.”

An interesting point: The men who shovel off to meet their makers following a snowstorm, or who have to call an EMT after putting ax to wood, aren’t doing aerobic activities. There’s no endurance component. Snow shoveling and wood chopping are anaerobic activities–strenuous efforts that can’t be continued longer than a few minutes without stopping to rest.

In other words, these activities resemble strength training and are very different from running or cycling. So you’d probably guess that weight lifting also has a pumped-up body count.

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