Daylight-saving time is literally killing us

The reason that springing the clocks forward can kill us comes down to interrupted sleep schedules.

Daylight-saving time is a killer.

The annual ritual in which we “gain” an hour of evening light by pushing the clocks forward may seem like a harmless shift. But each year, on the Monday after the springtime switch, hospitals report a 24% spike in heart attack visits around the country.


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Just a coincidence? Probably not. Doctors see the opposite trend in the fall: The day after we turn back the clocks, heart attack visits drop 21% as people enjoy a little extra pillow time.

“That’s how fragile and susceptible your body is to even just one hour of lost sleep,” sleep expert Matthew Walker, author of How We Sleep, previously told Business Insider.

The reason that springing the clocks forward can kill us comes down to interrupted sleep schedules. This Sunday, March 10, instead of the clock turning from 1:59 to 2:00 a.m. as usual, it will tick to 3:00 a.m. instead.

For those of us who will be asleep in bed, researchers estimate we’ll all deprive ourselves of an extra 40 minutes of sleep because of the clock change. And night-shift workers will only get paid for seven hours of work instead of the usual eight, according to federal law.

Walker said daylight-saving time (DST) is a kind of “global experiment” we perform twice a year. And the results show just how sensitive our bodies are to the whims of changing schedules: In the fall, the shift is a blessing, and in the spring, it’s a fatal curse.

In addition to the tragic heart-attack trend, which lasts about a day, researchers estimate that car crashes caused by drivers who were sleepy after clocks changed likely cost an 30 extra people in the US their lives over the nine-year period from 2002-2011.

“The brain, by way of attention lapses and micro-sleeps, is just as sensitive as the heart to very small perturbations of sleep,” Walker explains in his book.

The problems don’t stop there. DST also causes more reports of injuries at work, more strokes, and may lead to a temporary increase in suicides. Our bodies may not fully recover from the springtime bump for weeks.

Why we ‘save’ daylight for the later hours of the day

Daylight-saving time was originally concocted as a way to save energy in the evening, and was implemented during World War I in Germany. But more recent research suggests it’s probably not saving us any megawatts of power at all. There is some evidence, however, that extra evening light can reduce crime and increase the time people spend exercising, at least in certain climates.

Worldwide, fewer than half of all countries participate in this biannual clock-changing ritual.

Not everyone in the US follows it either. Hawaii and Arizona ignore DST, since it makes less sense to shift the clocks when you live near the equator, where the sun rises and sets at roughly the same time every day.

Residents and lawmakers in California and Florida are also trying to ditch the switch. Voters in the Golden State opted to get rid of the annual clock change in the 2018 midterm elections, and Florida lawmakers enacted the “Sunshine Protection Act” aimed at doing the same thing last March.

Pennsylvania, Texas, Washington, and Idaho are all angling to do the same, with proposed legislation in the works. But the shift to a permanent daylight-saving time plan isn’t something states can decide for themselves: the measures require a green light from Congress in order to take effect, something both California and Florida have yet to receive.

Meanwhile, the tradition inevitably costs some people their lives. So while you might enjoy the extra daylight next week, be mindful about your heart and your driving.

This article first appeared in Business Insider


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