Does Daylight Savings Cause Heart Attacks?

If someone told you that daylight savings could cause heart attacks, would you believe it? Would you fear that you make never wake up just because we set our clocks an hour forward? Would you move to Asia, South America, or any place where daylight savings isn’t observed in order to avoid it? Studies show that the rate of heart attacks increase by 25% the following Monday when daylight savings occurred compared to every other Monday of the year. But how does something that we do twice a year, that we have all accepted as “law of nature”, could potentially be life threatening?

There are two times when daylight savings occur: the spring daylight savings where you turn your clocks an hour forward and the fall daylight savings where you turn your clocks an hour backwards. Studies show that the daylight savings that turn your clocks an hour forward increased risk of a heart attack by 25%. The daylight savings which we turn our clocks an hour backwards does not increase risk of a heart attack. On the contrary, researchers found that turning our clocks an hour back lowered the number of heart attacks by a whole 21%.

Daylight savings don’t directly cause heart attacks. The reason why there is an increased rate of heart attacks the Monday after daylight savings is because it disrupted your sleep schedule. Daylight savings cause disruptions in your biological processes. Our bodies have a “biological clock.” If you sleep at the same time every night and wake up to your 8:00 AM alarm every morning, your body gets accustomed to that time frame. When daylight savings occur, that 8:00 AM alarm becomes 7:00 AM, disrupting your biological clock.

Sleep deprivation is linked to an increased risk of heart attack. People who get less than 6 hours of sleep a night has a higher risk of heart disease, diabetes, and stroke. People have more heart attacks because they get one less hour of sleep. When sleeping, your body conducts a lot of biological processes such as glucose metabolism, blood pressure regulation, etc. Because you woke up an hour before your usual time, your body’s processes got disrupted, hence you become more prone to a heart attack. This is especially worse if you have a heart disease or don’t sleep a healthy amount only lose one more hour due to daylight savings.

Cardiology fellow, Dr. Amneet Sandhu, M.D., conducted a study examining 42,000 hospital admissions in Michigan. He found out the average number of heart attack patients on Mondays is 32. On the Monday following daylight savings however, there was an average of 8 additional heart attacks. The study is large enough to say that this is no coincidence or that it is very difficult to say that this is pure chance.

It is clear that people prone to heart attacks should take extra caution around the time of the spring daylight savings. If daylight savings causes an increased risk of heart attack, should we not have daylight savings at all? I’d rather have the sky become dark by 4pm in the winter than have a heart attack, no? Another way to prevent having a heart attack on daylight savings Monday would be to prepare for it in advance. A week or two before daylight savings occur, sleep a few minutes earlier and wake up a few minutes earlier than usual. For example, if you sleep at 10:00 PM and wake up at 7:00AM, try sleeping at 9:50PM and waking up at 6:50AM. The goal is to shift your sleep schedule an hour back slowly. By the time the day of daylight savings comes, your sleep schedule will be 9:00PM to 6:00AM. That way, when the time changes, it will become 10:00PM to 7:00AM again. Small increments of change is less impactful than suddenly missing a whole hour. So the next time someone tries to wake you up earlier than usual, you can tell them, “Don’t wake me up early or else I might have a heart attack.”

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