Daylight saving time doesn't just cost you sleep -- there may be hidden health hazards too

The Health Risks Associated With Daylight Saving Time

People complain about Daylight Saving Time, approaching Sunday at 2 a.m. Eastern, because they lose an hour of sleep. But a recent study found the change in time can also pose serious health risks.

The study, published to the American Academy of Neurology on Feb. 29, found that DST may be associated with a higher risk of an ischemic stroke (blood clot in the brain).

READ MORE: What Is Daylight Saving Time? The History Behind Why We Set Our Clocks Forward and Back

"Previous studies have shown that disruptions in a person's circadian rhythm, also called an internal body clock, increase the risk of ischemic stroke, so we wanted to find out if daylight saving time was putting people at risk," the study's author Jori Ruuskanen, MD, PhD, of the University of Turku in Turku, Finland, said.

The research found that the rate of ischemic stroke in Finland was 8% higher within the two days following DST — but the rates lowered once those two days passed, suggesting it had something to do with the transition.

Another eye raising result of the study was that people with cancer were 25% more likely to have a stroke during daylight saving time compared to other time periods, and those over 65 years old were 20% more likely to have a stroke.

Learn more about daylight saving time:

Daylight Saving Time Facts
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Daylight saving time doesn't just cost you sleep -- there may be hidden health hazards too
Benjamin Franklin essentially came up with this glorious time exchange in 1741, when he was an ambassador for Paris.Though it wasn't until World War I that Europe truly started to implement Daylight Saving Time in order to bolster their war efforts.

DST before 2007 used to fall a few days before Halloween, but since the holiday tends to come with increased accidents it was moved to the first Sunday in November, according to Acurite.

Though, some dispute that the change was made to allow Trick or Treaters to stay out longer. 

Circa 1955: Silhouette of a witch on a broomstick flying over the skyline of New York City, Halloween.

(Photo by Lambert/Getty Images)

Arizona and Hawaii are the only two U.S. states that don't observe Daylight Saving Time. Pro: they don't have to worry about changing their clocks. Con: they never 'gain an hour.'

When World War II came around-- saving time was fashionable again and everyone wanted to get their hands on daylight saving time. However, it was near complete confusion in the United States-- there was no uniformity. According to Live Science, "One 35-mile bus ride from Moundsville, W.Va., to Steubenville, Ohio, took riders through no less than seven different time changes."

It was officially adopted by the U.S. in 1966. 

DST can affect the time you're born-- on paper that is. A baby could be born at 1:55 a.m. during daylight saving time, with another born ten minutes later, marked as 1:05 a.m.

Freaky, huh?

We hate to be that person-- but Daylight Saving Time is not plural, though many say and spell it as such. So, if you want to be that person you can spend the day correcting all of your friends when they say "daylight savings time."
Many countries near the equator do not adjust their clocks for daylight saving. Japan and China don't observe DST at all, and Antarctica doesn't either.

READ MORE: Will My Phone Automatically Change for Daylight Saving Time? Here's How You Can Be Sure

"Further studies must now be done to better understand the relationship between these transitions and stroke risk and to find out if there are ways to reduce that risk," Ruuskanen said.

"Stroke risk is highest in the morning hours," Ruuskanen told CNN. "Previous studies have also shown that the disruption of the circadian clock due to other reasons (e.g. due to rotating shift work) and sleep fragmentation are associated with an increased risk of stroke.

Ruuskanen stressed that the data shows correlation, not causation. "However, we did not know whether stroke risk is affected by DST transitions. What is common in these situations is the disturbed sleep cycle, while the immediate mechanisms for the increased risk are unknown at the moment."

Past studies have shown a correlation between DST and increased health risks as well. A 2014 study at the University of Michigan showed a 24% increase in those admitted to Blue Cross Blue Shield of Michigan Cardiovascular Consortium database for heart attacks during weeks following DST in the spring but a 21% decrease in the weeks following fall DST (when we gain back the hour of sleep).

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Similarly, a 2012 study at the University of Alabama at Birmingham showed a 10% increase in heart attacks following DST. But, again, the rate decreased by 10 percent after DST in the fall, so DST hasn't been shown to affect the overall rate of heart attacks.

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