I’ve always heard/been told to be careful while shoveling snow, that you’re more likely to have a heart attack. Why would I be more likely then as opposed to exerting myself during normal temperatures?
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Adding to everyone else’s point that it is more exercise than many people get, it is also surprisingly strenuous exercise. People don’t often think shoveling snow is hard work but it is. Snow is much heavier than people think it is. In addition few people own a shovel that allows for proper leverage which means they are exerting even more force to lift and move the snow all the way out at the end of the shovel. If they are bending to get better leverage they are engaging several muscle groups, many of which may not routinely get good use in the person’s daily life. And since you exert high effort in short bursts many people don’t pause to recover properly as they go.
Shoveling snow is not just going out and pushing some light fluff around. It can be a full body rigorous workout.
One way heart attacks happen is when stuff in your blood vessels (plaque, clots) gets lodged in the most important tubes going into the heart. It’s kind of like stepping on a hose that’s turned on. The water stops coming out.
Well, in the heart’s case, it’s blood, and the heart needs that blood to keep coming in to pump it out.
When you’re shoveling snow, your body is pumping blood harder and faster both for warmth and to feed your muscles that are doing a lot of work. When the heart is pumping harder and faster, there’s a bigger chance of the tubes getting jammed, and then – bam – heart attack.
Current med student here, and we literally covered this exact subject in this morning’s lecture (going to med school in Wisconsin so it’s pretty relevant here).
A little bit of necessary background: plaques build up in arteries over the years, which reduce the effective size of the inside of the artery and thus reduce blood flow. When this happens in the arteries that supply blood to the heart, it can cause pain (called angina) when oxygen demand in the heart increases, usually due to increased physical activity. In more severe cases, the blood flow to the heart can be reduced enough to actually kill part of the heart muscle when oxygen demand increases, this is one type of heart attack (NSTEMI, this part isn’t ELI5-appropriate I’ve just provided it so you can look it up if you want to). Another consequence of the plaques in the arteries is the formation of blood clots on them called thrombi. These thrombi cause even further blockage of the artery and reduce blood flow even more. The most dangerous part about a thrombus, though, is that it can break off and travel to a smaller artery where it can cause complete blockage of that artery. This process is called thromboebolism. If a clot breaks off and travels into one of the arteries that supply the heart, it can completely cut off blood supply to the part of the heart that is fed by that artery. This is another type of heart attack that is even more serious than the one mentioned above. Probably the worst-case scenario is if it blocks the left descending artery, which supplied the strongest and hardest working muscle in the heart, the left ventricle. This leads to the worst type of heart attack (STEMI, again, not ELI5-appropriate), and when it happens in this part of the heart it is nicknamed “the widowmaker” because it is so commonly fatal.
As to why these events commonly happen when people are shoveling snow, that’s mostly due to the fact that it can be pretty strenuous physical work and is often the first significant physical activity that people have had in several months if not longer. This leads to the heart working much harder than it has in a long time, meaning it requires more oxygen than it has in a long time and potentially more oxygen than the arteries are now capable of delivering. It also means an increased chance of a thrombus that may have formed elsewhere in the body breaking loose and potentially blocking one of the arteries to the heart.
Adding to what others have said, doing any strenuous activity in the morning increases your chances of having a heart attack. We have a spike on cortisol levels right before we wake up, as a way to prepare our body for the coming increase in activity. This paired with a sedentary lifestyle and the cold weather can increase the chances enough so that it is statistically relevant
Usually it is in the morning when heart attack risk is highest. This is usually among the elderly and unfit. Also, because it’s cold outside, there’s also a vasoconstriction effect (narrower blood vessels) It’s heavy exertion for which people aren’t fit to handle basically, at the worst time, and under awful weather conditions. Just keep fit year-round and keep active, you’ll live better and live longer.
Simply put, a heart attack is caused by a clot in one of the arteries that bring fresh, oxygenated, blood to the heart. It starts as plaque building along the walls of the arteries. That plaque eventually breaks free and becomes a clot. The clot lodges itself in the artery and prevents anything downstream from receiving fresh blood. When tissue stops receiving fresh blood (specifically, oxygen that the blood is carrying), it starts to die. When the tissue dies, it is no longer functioning.
When heart tissue dies, it no longer contracts. Which means it’s no longer helping pump blood to the rest of the body. If the rest of the body isn’t getting enough fresh blood, *those* tissues start to die too. Then everything comes crashing down.
That’s about the easiest way to explain what a heart attack is and why it’s bad.
Now, there are plenty of risk factors for cardiovascular disease (the general term meaning something wrong with your cardiovascular system). The short version of it is that these all make cardiac events more likely to happen by making these plaque build ups more common and make it easier for them to break off and form clots.
The body reacts to exertion (cells needing more oxygen) by increasing the heart rate. That in turn, increases your blood pressure. High blood pressure is one of the first diagnoses in the cardiovascular disease pathway. So if you already have high blood pressure, usually from poor diet and lack of exertion, and then suddenly you exert yourself, causing your HR to increase and thus your BP, you’re now at even greater risk.
All that pressure pushing through your arteries and then it finds one of these plaque deposits. It knocks it loose, turning it into a clot. The clot travels downstream until it gets stuck. It gets stuck and cuts off blood flow. Now the heart has all this increased demand for oxygen (it has to work harder) and parts of the heart are suffocating and thus dying.
It’s a downward spiral that often ends in death. Cardiovascular disease is usually #1 in causes of death in adults, year after year.
ELI5: You know when you’re washing dishes and there’s that real tough, stuck on, piece of food? How do you get that food off? You increase the water pressure coming out of the nozzle.
Shoveling snow, or having sex (maybe not ELI5), or any other physical exertion, in a person who usually does not exert themselves, cause the water pressure to go up.
Eventually the food (the plaque / clot) breaks free and goes down the drain. Except when it goes down the drain, it clogs it. If you don’t clear it quickly, your sink stops working because it’s overflowing.
So you call a plumber (911) to come to your house immediately, and pour some drain cleaner (thrombolytics to dissolve the clot) to clear it, and if that doesn’t work, they snake it (cardiac cath). If *that* doesn’t work, they might have to open up the cabinet and cut out the bad piece and replace it (Coronary Bypass Surgery).
All the while, the sink is running and making a mess. And you as the homeowner? You’re dying.
This is why rapid recognition is vital. The faster you get treatment, the faster that clot is cleared, the less tissue is damaged.
Time is tissue.
You’re not *likely,* it’s exertion which puts everyone more at risk of a heart attack. Whether you have one or not has a lot to do with your health but even healthy as an ox people die from simple exertion like shoveling a driveway or swinging a golf club. Don’t let that discourage you from cardio health though that’s very important and the biggest variable when it comes to heart attack risk.
Ironically shoveling your driveway is exercise and does get your heart rate going for a period of time so it’s literally the exercise that you need in order to lower your risk of having a heart attack while shoveling. 🙂
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You actually have a higher chance of having a medical issue while snow blowing. Most snow blowers are large and cause a significant amount of vibration to be transferred into the person running the blower. The vibration can cause plaque or a blockage in your body to become dislodged and travel somewhere worse like going into the heart, brain, or lungs causing a blockage / heart attack / stroke / ect. As you age, if you are physically capable of doing so, you should consider shoveling rather than snow blowing for this reason.
1. It’s high intensity without much warm-up, often done by people who are not athletic at all
2. Cold constricts your blood vessels, making it more likely for a clot to block off a whole artery than if they were larger
3. Cold also makes some components of your blood more viscous, resulting in incrementally more common clotting
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