Hundreds of men, including some of the fittest in the world, have taken their last breaths wearing running shoes. This is a story about how to outsmart the Grim Reaper.
A man goes for a run. Just 6 kilometers—nothing special, really, for a trained marathon runner who usually runs more than 15km a day, 7 days a week. No one knows why he stops just a few dozen meters from his front door—perhaps to check his pulse, perhaps because his shoelaces have come undone—but everyone knows what happens to Jim Fixx, the 52-year-old champion of running. He dies.
You have probably heard that story. But you may not know about Edmund Burke, who was as passionate about cycling as Fixx was about running. He died on a training ride last fall at the age of 53.
You have almost certainly never heard of Frederick Montz, David Nagey or Jeffery Williams, three brilliant physicists at Johns Hopkins University who died while running. The oldest of the three was 51.
You would think these models of physical fitness would live to be 100. Yet every year, some of them drop dead barely halfway to a hundred.
This raises 2 questions. The first is obvious: why do the hearts of such highly trained men fail during exercise that is supposed to strengthen them? The second is so radical that it could be considered a betrayal of fitness and healthy living: is there something wrong with our understanding of endurance training as a way to improve health and extend life?
I have been skeptical about aerobic exercise for years. But the answers surprised even me. Make sure you are sitting down—you will need something solid beneath you as you read what follows.
The road to nowhere
Just a generation ago, the idea that a well-trained endurance athlete could simply drop dead was inconceivable. Dr. Thomas Bassler went so far as to claim that anyone who could complete a marathon in less than 4 hours should have no heart problems at all. He conducted a study of 14 marathon runners who had died of cardiovascular disease and found that all of them were malnourished. Unfortunately, he reported his views in the July 27, 1984 issue of the Journal of the American Medical Association. Fixx had died 7 days earlier.
Today, no one believes that endurance training provides immunity against anything, whether sudden death from heart disease or a stroke. Every time you lace up your running shoes, there is a chance you will never come home. Every expert knows this.
“I think the risk is unavoidable, and it is greater than we realize,” says Paul Thompson, head of preventive cardiology at the University of Hartford and a researcher studying the links between exercise and sudden death. One of Dr. Thompson’s studies found that 10% of the heart attacks treated at that hospital were associated with exercise. “These attacks tend to happen to people who are out of shape,” he says. “But unfortunately, that does not mean they are the only people affected. There are also those incredibly fit guys who go for a run and drop dead.”
Research by Dr. Thompson and others shows that about 1 in every 15–18 thousand people who exercise dies each year. That works out to 1 death per 1.5 million workouts. Strangely, those who train the hardest are at the greatest risk. Here is a brief breakdown based on a frequently cited study published in 1982 in the New England Journal of Medicine.
1 death per 17,000 men who exercise for 1–19 minutes a week
1 death per 23,000 men who exercise for 20–139 minutes a week.
1 death per 13,000 men who exercise for 140 or more minutes a week
I had to look at these figures twice to take in what they showed: the death rate is highest among those who exercise long and hard, and far higher than among those who exercise briefly and intensely. Worse still, even those who do almost nothing have a much lower risk of sudden death.
Yet thousands of studies have shown that aerobic training leads to a healthier heart and a longer life.
It makes you wonder why doing more of something healthy is worse than doing less.
A look back
A 1970 study of San Francisco dockworkers provided strong evidence for the theory that physical activity helps prevent heart disease. Dockworkers in supervisory roles, whose jobs were largely sedentary, had 25% more heart disease than those doing the manual labor.
An important point about this study and others like it: the participants were not doing steady-paced endurance work. They walked, stopped, picked things up, put them down and so on.
Numerous studies followed, attempting to establish how much physical activity, and at what intensity, was needed to prevent heart disease. The Harvard Alumni study showed that heart disease risk began to fall when weekly energy expenditure exceeded 500 calories and continued to decline up to 2000 calories. Beyond that, it leveled off: more exercise offered no additional protection.
The lower figure does not represent a particularly demanding training load: a 90kg man walking for 2 hours a week at 5km/h burns 600 calories. The upper figure is not especially demanding either. Just 7 hours of walking will do it. (Lighter people burn fewer calories; heavier people burn more.)
Intensity is a separate issue: some studies show that moderate-intensity exercise, such as walking, bowling and golf, is good for the heart, while others suggest it is less beneficial.
Some studies also measure the relationship between heart disease risk and activity levels, with some interesting results: at a training load of 75% of the maximum—that is, among people who exercise more than the other 75% of the population—exercise offers no protection against heart disease. In fact, the risk even increases slightly among those who exercise the hardest. In other words, the extremely active are more likely to die than the less active.
The snow problem
One reason the phenomenon of exercising yourself to death is difficult to understand is that few people whose deaths may have been caused by training actually die while training—there are only about 100 such cases a year. We therefore need to take a broader view and look at cases in which people die during physical exertion. A 1993 study examined 1228 nonfatal heart attacks, 54 of which occurred during or immediately after physical exertion. (The threshold was 6MET = 6 x the energy expenditure required at rest. Activities classified as 6MET include strenuous strength training, chopping wood and shoveling snow. Jogging = 8MET.)
The researchers divided the cases into three categories and found that 18% of heart attacks were associated with lifting and pushing, 30% with either running or sports (especially racket sports), and 52% with household chores such as chopping wood.
That brings us to the leading physical activity associated with sudden death: shoveling snow.
A researcher at William Beumont Hospital identified 36 deaths in the Detroit area associated with clearing snow after two major snowstorms. (Some of those who died had been using a snowblower.)
It is not hard to see why cold conditions lead to so many deaths. “Your heart rate shoots up as high as it does when sprinting on a treadmill. Combine that with cold weather, which constricts your arteries, and you have a perfect recipe for disaster.”
An interesting observation: men who shovel snow or chop wood are not doing aerobic activity. These tasks lack an endurance component. Shoveling snow and chopping wood are anaerobic activities—strenuous tasks you cannot sustain for more than a few minutes without resting.
In other words, they are more like strength training and bear no resemblance whatsoever to running or cycling. That immediately raises the question: does strength training also lead to death?
NO. In fact, there are almost no known deaths. A couple of men die each year after lowering a barbell onto their throat, and there are a couple of documented accounts of strokes, but you have to look very hard to find cases of sudden death associated with strength training. Patients who have survived cardiac arrest undergo strength training as part of their rehabilitation, and there have been no reports of any of them dying as a result.
Strength training protects your heart in two ways. First, says Franklin, it produces a predictable rise in diastolic blood pressure, which indicates the pressure at which blood returns to the coronary artery. (If your blood pressure is 120/80, your diastolic pressure is 80.) This differs from aerobic exercise, where systolic blood pressure (the 1st number) rises while diastolic pressure stays the same or tends to fall. Both readings rise to some extent during strength training, meaning that the pressure difference driving blood back to your heart remains similar to what it is at rest.
Second, most of us tend to hold our breath when lifting. This raises blood pressure considerably and used to be a major concern for doctors, who feared it could cause an aneurysm. Recent studies, however, show that briefly holding your breath creates counterpressure on the blood vessels within your body, neutralizing the rise in blood pressure. The aneurysm is averted.
In other words, your body seems designed to protect itself during brief bouts of maximum exertion, and men who work out at the gym should not have to worry about the Grim Reaper lurking there.
The final lesson
Still, you should not count on that. The fact that few deaths from strength training have been reported does not mean they cannot happen. Barry Franklin points out that most men who die suddenly as a result of exercise are middle-aged, whereas most men in gyms are young. Older men have started going to gyms too, but the research used in this article dates from the 80s and early 90s, when gray hair was a rare sight in the gym. If a middle-aged man exercised, he probably ran or cycled.
Older people now regularly attend health clubs too, and you can be sure that, for some, their final cooldown will take place in the morgue. Franklin recently investigated deaths at the largest health club chains. Using membership card records, he found that 71 deaths had occurred on the gym floor over 183 million visits. Unfortunately, there is no information on which exercises people were doing when they died, so no firm conclusions can be drawn.
But Franklin found 2 interesting trends in the data. The average age of club members was 32. The average age of the 71 people who died was 53. Those 71 people also averaged just 2 gym visits a month. They may have exercised outside the gym, but Franklin doubts it. If they had, most of them would probably still be alive.
That is also the most logical explanation here: the best way to avoid dying during exercise is to exercise. “The people at greatest risk are habitual couch potatoes with either known or undiagnosed coronary artery problems.”
You do not have to become a marathon runner (that can be dangerous), but you should exercise frequently; many studies show that what counts is the amount of time you spend being active each day. (Moving around and getting things done.)
Some endurance training is perfectly OK if you enjoy it. Strength training is probably more than OK: it prepares your body for brief, strenuous tasks such as shoveling snow, which is one of the activities most likely to kill you if your body is not ready for it.
We cannot offer specific strength training recommendations to prevent sudden death, but we do know that it is extremely difficult to kill yourself doing it. For example, even if we assume that every death in a gym was associated with strength training, that still gives us just 1 death per 2.5 million workouts, a considerably lower rate than the figure of 1.5 million for aerobic training.
But every time you exercise and push yourself hard, whether on a running track or in a power rack, you take a small risk in the face of a major threat. “It is like investing in stocks,” Thompson comments. “You invest your money for long-term gains, but a small crash can dash all your hopes. Everything carries some risk.”
Author: Lou Schuler/menshealt.com
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