On Sunday, all U.S. states (with the exception of Hawaii and Arizona) resumed daylight saving time (DST), moving their clocks forward by one hour. But thanks to a new Senate decision, this might not happen again. On Tuesday, the Senate passed legislation that would make DST permanent from 2023, meaning we would no longer need to change our clocks twice a year. The bill, titled The Sunshine Protection Act, was passed by unanimous consent (when the legislative process is accelerated through the agreement of all representatives or senators). The House of Representatives still needs to pass the bill before it is given to President Biden for sign-off. There is still no word from the White House on whether the President is in favor of the bill.
DST was rolled out 1966 as a means to conserve energy by allowing for more daylight in the evening. But over the years, health experts, sleep advocates, and the general public have pushed for there to be a year-round time due to the sudden time change having a range of potential adverse impacts, including more traffic accidents and even a link to increased heart health issues. According to an Associated Press-National Opinion Research Center poll in 2019, 38% of people aged 45 and older and 22% of people under 45 said they would rather not change their clocks and would prefer year-round daylight savings. Between 2015 and 2019, 29 states introduced legislation to scrap the twice-annual changing of clocks. Last week, the House of Representatives Committee on Energy and Commerce held a hearing on the matter. “It’s a weekend that makes a lot of us unhappy. The loss of that one hour of sleep seems to impact us for days afterwards. It also can cause havoc on the sleeping patterns of our kids and our pets. This is all an inconvenience, but unfortunately the changing of our clocks can have impacts on our health,” said committee chairman Frank Pallone.
But is this true? Does changing the clocks really have a significant impact on our health? We spoke to Lourdes DelRosso, MD, a board-certified sleep physician and associate professor at the University of Washington, to find out more. There’s significant scientific evidence pointing to daylight saving time increasing the odds of issues like cardiovascular emergencies, traffic accidents, and emergency department visits, Dr. DelRosso tells SELF. In 2020, the University of Colorado published a study in Current Biology analyzing 732,835 fatal car accidents in the U.S. from 1996 to 2017, ultimately finding that the risk of fatal car accidents rose by 6% in the five workdays after the spring DST transition. The risk was highest in the morning and in western states. “Our results support the theory that abolishing time changes completely, would improve public health and reduce geographical health disparities,” the researchers concluded. And a 2018 study in the Journal of the American Heart Association analyzed hospital admissions for atrial fibrillation (an irregular, rapid heartbeat that can lead to blood clots in the heart) from 2009 to 2016, finding a significant link between the beginning of DST and increased hospital admissions for this health issue.
The reason why these negative impacts can stem from the changing of the clocks may come down to “circadian misalignment contributing to sleep debt,” Dr. DelRosso tells SELF. Circadian misalignment refers to a disconnect with the sleep-wake cycle (our biological patterns of sleeping for around eight hours a night and having around 16 hours of being awake). Your circadian rhythm governs a lot of physiological processes, so this misalignment can potentially have a big impact, as the data show. And sleep debt happens when you don’t get enough sleep over multiple days, so the lack of sleep starts building up over time, the Centers for Disease Control and Prevention (CDC) explains. According to the CDC, as sleep debt builds, the normal functioning of the body and brain “deteriorate,” which helps to explain the increased number of traffic accidents which occur after the clocks change (along with less dire but still important issues like generally feeling exhausted).
Ultimately, it’s not yet clear how likely the U.S. is to do away with changing our clocks twice a year. But moving to a year-round national clock would mean one less factor to disrupt people’s sleep-wake cycles, which experts hope will make life safer overall.