The End of Daylight Saving Time Can Be Bad for Your Health—Here's How

Here are 4 ways "falling back" or gaining an hour can negatively affect your health and safety.

Daylight saving time ends on the first Sunday in November at exactly 2 a.m. local time. Most Americans "fall back" by one hour and notice the sun sets a little earlier as standard time resumes. Many of us look forward to gaining that extra hour of sleep but, as it turns out, those extra ZZZs may not be as beneficial as we think.

Daylight saving time began in 1918 as a wartime conservation effort. After WWI ended, the practice fell out of style as it was incredibly unpopular, according to, especially with farmers. Daylight saving returned during WWII and then, in 1966, the U.S. government passed the Uniform Time Act, which finally standardized daylight saving time for nearly every state.

Now, onto the risks this over-100-year practice poses to your health.

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A 2016 Danish study that examined 185,419 diagnoses of depression between 1995 and 2012 found an 8 percent rise in depression in the days following the time change in the fall.

"We are relatively certain that it is the transition from daylight saving time to standard time that causes the increase in the number of depression diagnoses and not, for example, the change in the length of the day or bad weather," wrote Søren D. Østergaard, one of the five researchers behind the study. "In fact, we take these phenomena into account in our analyses."

"Our results should give rise to increased awareness of depression in the weeks following the transition to standard time. This is especially true for people with a tendency toward depression—as well as their relatives." Østergaard continued. "Furthermore, the healthcare professionals who diagnose and treat depression should also take our results into consideration."

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Traffic Accidents

Gaining an extra hour of rest may sound beneficial, but it could cause us to be groggy, which isn't ideal for getting behind the wheel. According to a 2001 study, the risk of traffic accidents increases on the Saturday night before switching back to standard time as more people are on the roads later than usual.

"The behavioral adaptation anticipating the longer day on Sunday of the shift from DST in the fall leads to an increased number of accidents" the study concluded, "suggesting an increase in late night (early Sunday morning) driving when traffic-related fatalities are high possibly related to alcohol consumption and driving while sleepy. Public health educators should probably consider issuing warnings both about the effects of sleep loss in the spring shift and possible behaviors such as staying out later, particularly when consuming alcohol in the fall shift."

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According to a Finnish study reported by WebMD, the national incidence of stroke rises by about 8 percent over the two days following daylight saving time transitions. As to why that happens, it all comes down to messing with our circadian sleep rhythms.

"Sleep is associated with many physiological changes that are normally thought of as being relatively protective against stroke, like lower blood pressure," said Dr. Andrew Lim, a neurologist at Sunnybrook Health Sciences Center who was not involved in the study.

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Apparently, getting a bit more sleep inspires people to commit crimes. According to a 2017 study by University of Pennsylvania scientists who specialize in criminology, psychiatry, and psychology, the assault rate spikes just after the clocks fall back.

"Sleep problems have previously been associated with increased antisocial and criminal behavior, so we were surprised to find that increased sleep was associated with increased offending," study author Adrian Raine said in press release. "This discrepancy is likely due to the fact that 40 to 60 minutes of lost sleep in one night is just not the same as months, or even years, of poor sleep."

Maybe Arizona and Hawaii are really onto something by forgoing daylight saving after all.

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  1. Varughese J, Allen RP. Fatal accidents following changes in daylight savings time: the American experience. Sleep Med. 2001;2(1):31-36. doi:10.1016/s1389-9457(00)00032-0

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