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The dark side of daylight saving time

Coming March 11, roughly 1.6 billion people will move their clocks forward one hour and pour themselves an extra cup of coffee to make up the hour of sleep lost due to daylight saving time.

Back in 1784, Benjamin Franklin suggested a way to save sunlight and use fewer candles during the winter months. However, it took until March 1918 for a plan to be adopted that established daylight saving time in the U.S. that would preserve daylight and provide standard time.

Even though DST has become the norm, there are many adverse health effects that are brought on by this sudden time adjustment. The “circadian rhythm” is the natural rhythm the body goes through in a period of 24 hours, and several studies have shown that DST can harmfully disrupt this rhythm.

An article by the New England Journal of Medicine found that this loss of sleep can trigger stress hormones in the body that can cause inflammation. This raises the percentage of heart attacks in people already at risk of having cardiovascular issues.

A study by the Finnish Cardiac Society done in 2016 researched how the time transition led to an increased risk of a stroke.

“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,” said the Finnish study author Jori Ruuskanen.

The researchers took a decade of stroke data in Finland to find the average rate of stokes throughout the year. They then took the rate of 3,033 people who were hospitalized by strokes in the week following DST and compared it to 11,801 people who were hospitalized in the weeks after the time change. The research led them to discover that there was an eight percent raise in the first two days after the transition.

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