It is commonly repeated in the world of exercise science that there is no real danger presented to a person with normal health by working at or near one’s maximum heart rate. Yet, every year otherwise seemingly healthy people die (apparently) from overexertion – from shoveling snow, say. So does high levels of exertion present a risk factor to some people? Why, precisely? Do these people all have some underlying heart disease that is exacerbated by the sudden hard work?
People die when their heart can’t deliver. I don’t think it matters if they are having sex, shoveling snow, or eating pizza.
I think part of it is because there is a difference between “working out” and performing a task.
Exercise is a voluntary activity; it’s something you do on your own time, at your own pace, beginning and ending when you choose. Shoveling snow OTOH, is a task. It’s something you *have *to do to either comply with local laws (clearing the sidewalk), or more typically so you can go about your normal day (digging out your car/driveway so you can leave the house), and it ain’t done until it’s done. You can’t just decide to only shovel halfway down the driveway and then still go out. So people will push themselves too far, overexert themselves and start having problems.
I would imagine that even a perfectly healthy and physically strong person can potentially damage themselves if they are performing at or near their maximum heartrate for an extended period of time. However, I’d also imagine that yes, some underlying medical condition, known or unknown to the individuals that experience these issues while shoveling snow plays a large part in the majority of these occurrences.
It’s a real phenomenon. See this article. What I’m wondering about is the specific relationship between exertion and heart disease. According to my understanding, the mechanism of most heart attacks doesn’t have much to do with heart rate. But I’m obviously wrong.
Eta: this was a response to post #2
I suspect that deaths caused by shoveling snow has little to do with heart rate. The heart attack is triggered when increased exertion, and the raised blood pressure and blood flow that accompanies it, causes a plaque rupture, which then causes a blood clot and an occluded artery.
I think there has to be some underlying condition present (i.e. arrythmia, peripheral clots, Marfans and Ehlers-Danlos syndromes, undetected hypertension or silent heart attacks) that makes a drop-dead-while-shoveling-snow event more likely. I can cycle 20 miles with my heart rate near maximum for certain periods and I’m not dead yet. OTOH, Jim Fixx (running guru of the 70s and 80s) died relatively young despite running marathon-length distances. The difference could be that he had an underlying condition that caught up with him that I don’t have, or that I don’t have yet.
Bingo. Well, phrased like that, it may be an overstatement, but yes, shoveling snow is a classic over-exertion activity for those with cardiovascular disease (CVD). Case reports of heart attacks during or soon after snow-shoveling are documented back to 1964 (Burgess, 1965).
Extreme exertion as a trigger for heart attacks is not limited to snow shoveling, either; 45% of on-duty firefighter deaths are due to myocardial infarctions. Multiple recent studies of the latter agree these deaths were initiated by emergency calls and occurred in firefighters with underlying CVD (e.g.:Kales, Soteriades, Christoudias, Christiani, 2003; Geibe, Holder, Peeples, Kinney, et al., 2008).
Any type of extreme exertion in a person with risk factors like hypertension, CVD, atherosclerosis, chronic smoking, etc., poses a risk of sudden cardiac death (Mittleman, Siscovick, 1993). One study (Mittleman, Maclure, Tofler, Sherwood, et al., 1993) noted a heavy physical exertion raised the risk of a heart attack by 5.9 percent. It further noted that those that don’t regularly exercise have a much higher risk of heart attacks in or soon after exertion.
The factors that DcinDC identified explain some socially-controlling factors for why we only hear about this during snow shoveling. Simply put, it is a type of activity most likely to push a person into extreme exertion against their better judgment.
It is also a type of extreme exertion that is that occurs in a broad section of the population but in a narrowly-restricted time and geography, and the deaths occur in public. Some guy dropping on a treadmill, while it does happen, happens inside his gym or health club, away from the general notice of passers-by, among a narrow section of the population, in a broadly-dispersed time and geographic pattern. The former will gather attention, the latter will only be noticed by those involved or direct spectators.
When you are shoveling snow, you don’t realize how much your body is being taxed. I have noted when I’m doing it that I don’t seem to have done all that much and yet my heart rate has gone up more than if I was exercising full out on a treadmill. You’re lifting a lot of weight – probably more than you’d lift using an exercise machine – and you tend to think “just a few more shovels and I’ll be done” instead of “Jesus I’m getting out of breath; I’d better quit.”
If you have an underlying condition, snow shoveling is the perfect way to bring it out, even if you’ve never showed any signs of it before.
FWIW, this happened a few years ago at the gym I was going to at the time. I was in the locker room getting dressed when folks started coming into the locker room talking about a guy on the gym room floor with EMTs working on him. By the time I finished getting dressed and walked out the EMTs were still working on him but had that “well, this is a waste of time but the specs say we have to keep trying for another two minutes” look about them.
The next day I asked the staff what happened, and they told me that a 45-year-old man simply collapsed near one of the weight machines and couldn’t be revived. Apparent heart attack, cause unknown (by the gym staff), did not survive. Never made the papers.
Look at it this way: trees occasionally fall down during calm weather, but they generally fall down during a storm. Hearts generally fail when they’re under stress.
If you don’t exercise regularly and then suddenly exert yourself, your chance of heart attack increases by almost 700%.
It’s even worse for snow shoveling since the cold environment tends to constrict many of the body’s blood vessels. That in turn causes a bigger strain on the heart since it then has to pump blood into a narrowed (i.e. constricted), and thus high pressure, circuit.
In addition to the above, snow shoveling (and other strenuous exercise) is a good way of unmasking not just “typical” atherosclerosis and coronary artery disease but other acquired, serious problems such as cardiomyopathy, and related heart disorders including those due to heart muscle inflammation such as a viral infection.
Almost everybody in a snow region shovels snow at times. A good percentage of people do absolutely no exercise during the year. Some of these, generally older, go out in the cold heavily dressed to shovel the snow. Snow can be heavy. The shoveling process can be repetitive. These same people have no practice and an inefficient shoveling form. Even a little snow puts heavy stress on the core areas of the stomach and back. The blood flow required to support the process is demanding. Those few folks on the marginal side of heart capacity succumb to demand with a heart attack. Sometimes, the heart attack is not directly related to clogged arteries. It can be from a temporary cramping of the arteries, for lack of a better term. Or they could have an undiagnosed arrhythmia that suddenly surfaces.
PS. People with diminished heart function who never exercise may not notice symptoms until they get down to 15-20% function. Those who are regular heavy exercisers will get clues much earlier and hopefully get treatment.
Also, this sort of death makes the news when it happens because at that time, everyone else in the area has just been shoveling snow too, so it provides a hook to interest a lot of people. It’s not just “Man dies,” it’s “Man dies doing what you were just doing; look at the bullet you just dodged.”
My late husband had his heart attack while shoveling snow at age 33. He “died” in that he had to be resuscitated a number of times while EMTs fought through a blizzard to get him to a hospital, then his heart stopped a number of times once in the hospital.
As KarlGauss said, it’s a combination of cold weather, poor condition, rare exercise, severe exertion, etc.
The act of shoveling puts enormous strains on the area at and around the heart muscles. This makes for a much higher rate of possible cardiomyopathy when persons in poor shape to begin with, over-exert their musculature and circulation around the heart.
Isometric exercise, even when non-aerobic, puts a large strain on the heart. I suspect for most out-of-shape snow shovelers, it is a fairly aerobic exercise anyway, with marked elevations of heart rate and blood pressure as they clear the snow.
Folks who have heart attacks shoveling snow almost always have underlying atherosclerosis. The added strain of shoveling outstrips the occluded heart vessel’s ability to supply blood and the individual infarcts.
There are other factors. One is that snow shoveling often occurs in the morning, already a time of increased heart attack risk for various reasons. Another reason is that there is a defined amount of work to be done–often in a hurry–so it’s not like an optional exercise run where you can quit when your body starts warning you. Shoveling snow after a big storm feels like an emergency to the shoveler, who goes out there and digs in until he is dug out. It’s sort of like putting a person on a treadmill for maximum exercise without the option of quitting.
There is, by the way, a very large danger of people with “normal health” working out to their maximum potential if by “normal health” you mean “asymptomatic health.” Unrecognized coronary artery disease is a major reason for sudden death, and a frequent precipitant is new, maximum exertion such as snow shoveling or intercourse with a new mistress. This is why nearly any exercise program will advise a middle-aged guy to “check with your doctor” prior to beginning a potentially strenuous exercise program.
I have been an EMT for over 30 years and remember many many more snow shoveling related emergency’s than sex relater ones. and it only snow in a few months for the most part.
I do not get excited about shoveling snow because I know how stressful it is.
Think about it this way.
If you have to stop 1/2 way through tieing your boots to catch your breath, you should know to take it very easy with the snow shoveling or like me, hire a young kid to do it for you.
There are very few good snow shovels to pick from, even though the stores are full of them. For me ( I am 5 1/2’-10") I remove the short handle from the old fashion Grain Scoop and add a long one so that I do not have to bend down so far to get a scoop full.
I suspect overdressing & overheating has a lot to do with it.
We normally only get one shovel-worthy snow per season here. Last time wife & I went out to shovel in 25F temps I wore a t-shirt & windbreaker. I got winded but not overheated. Wife did the usual dress-for-casual-walking-in-25F & got winded too, but also waaay too hot & sweaty for safety. Lesson (re-)learned.
When I went out yesterday morning to dig the car out, I was offered help by a young woman whose father had died shoveling earlier in the season. She was going around the neighborhood after this last big snowstorm and offering help to “older people”. (I suppressed a glare…hey, she was offering help with the absolute most-hated chore in my life!)
Fixx definitely had problems and is likely to have died a decade earlier if not for his running. According to Wikipedia