Why sleep scientists think Standard Time is best

People love the extra hour of sunlight at night, but there’s a cost to that

By Nicole Karlis

Senior Writer

Published March 12, 2023 1:48PM (EDT)

Sleeping man disturbed by alarm clock early in the morning (Getty Images/South_agency)
Sleeping man disturbed by alarm clock early in the morning (Getty Images/South_agency)

As spring nears, longer and sunnier days are ahead — until next November, of course.

Thanks to provisions of the Energy Policy Act of 2005, Daylight Saving Time commences on March 12 of this year. As our clocks perform their annual "spring ahead" dance in a majority of the U.S. (Arizona and Hawaii don't participate), most people look forward to livelier, and sunnier, evenings. For many, strolling outside under the sun at nearly 9pm is a hallmark of summer. The extra hour of daylight is so popular, there's even been a proposed legislation — the Sunshine Protection Act — to savor it permanently throughout the year, which an estimated 59 percent of Americans support. As DST is upon us, and yet another opportunity to make it permanent looms, sleep scientists are speaking out against the possibility as research suggests that the negative effects of DST on our collective health outweigh the benefits of longer daylight hours.

"Permanent Standard Time is better for human health," Dr. Anita Shelgikar, a professor of neurology at the University of Michigan Medical School told Salon. "And the reason for that is because Standard Time best aligns our internal clock with the world around us, and so the closer those two things can be aligned, the better for many, many health outcomes."

Specifically, Shelgikar said that when the time shift happens there's a "more exaggerated" mismatch between circadian rhythms and the world around us. When the clocks change and the times spring ahead, work and school responsibilities don't change and that can lead to sleep deprivation because it's harder to go to bed and wake up earlier.

Want more health and science stories in your inbox? Subscribe to Salon's weekly newsletter The Vulgar Scientist.

"Sleep deprivation can affect our mood, can affect our attention, and our decision making and ability to learn," Shelgikar said. "And those are things that can be adversely impacted by the time change."

"Permanent Standard Time is better for human health."

While people usually think that our bodies adjust to the time change, one study that surveyed 55,000 people suggested otherwise. Researchers found that people followed the seasonal progression of dawn, even on their days off when they could sleep in, and not the time on their clocks suggesting that a person cannot "trick" the body's natural sleep rhythms, which are based on the intensity of sunlight, by merely changing the clock.

Christopher Barnes, professor of organizational behavior, at the University of Washington's Michael G. Foster School of Business, told Salon he agrees that permanent Standard Time is best. In his own research he looked at the transitions in and out of changing clocks and found that when we spring ahead, people experience a "sleepy Monday."

"We experience the change on the weekend, but people tend to have a bit more flexibility in their weekend schedules, so it's not usually until that Sunday night and Monday morning where they experience some sleep deprivation," Barnes told Salon. "So Monday, they come in with a bit less sleep— one of my papers finds that it's somewhere around 40 minutes less."

Perhaps as a result of that sleep deprivation, the paper Barnes is referring to finds that the lack of sleep is associated with a 5.6 percent increase in work injuries.

"It's not a change in the daylight that's influencing the work directly, but it appears to be most likely tied to their sleep circadian rhythm disruptions," Barnes said. "So, transitioning into daylight saving time in the spring produces a spike in workplace injuries — in the fall, we do not see any benefits from the switch."

Barnes said based on research outside his own, there is a scientific consensus that humans are better off with extra hours of light in the morning instead of the evening.

"People imagine themselves having an extra hour to sit on their deck and maybe have a barbecue with their friends, and so that image is quite lovely," Barnes said. "But people don't understand the price they're paying for having that extra hour of light in the evening."

"People don't understand the price they're paying for having that extra hour of light in the evening."

Barnes compared the extra hour to permanently, and voluntarily, "inducing ourselves with an hour of jetlag."

In 2020, the American Academy of Sleep Medicine published a position statement opposing the Sunshine Protection Act, which would make Daylight Saving Times permanent. More medical groups around the world where the movement has also gained popularity have opposed it, too. Notably, if passed, this wouldn't be the first time the U.S. tried permanent DST.

"Congress enacted legislation to make Daylight Saving Time permanent 1974, and then repealed it less than a year later because what was happening was a number of children were getting struck by cars making their way to school in the dark,"  Dr. Pedram Navab, a neurologist, sleep medicine specialist and author of "Sleep Reimagined: The Fast Track to a Revitalized Life," told Salon. "People are partying more, they're going out more, but what they don't see is the indirect costs of that."

Navab said there are mental health consequences to permanent DST, too.

"You're not going to sleep as well, and it's worse for those who already have insomnia, and so they may not get up to go to work, and that's work productivity that's lost," Navab said. "People who have Seasonal Affective Disorder are at a disadvantage with permanent Daylight Saving Time because they need that sun in the morning to feel good to reset their circadian rhythm, and if they're getting that later on in the day, that's going to that's going to cause more anxiety or depression."

But there's no changing what's about to happen. If this article has raised concerns about the clock change, sleep scientists say there are ways to ease the transition.

"Try to go to bed and waking up 15 minutes earlier, rather than having one abrupt hour-long change, making small incremental changes in the days leading up can ease that transition," Shelgikar said. "It is also really important to expose your eyes to light in the morning."

By Nicole Karlis

Nicole Karlis is a senior writer at Salon, specializing in health and science. Tweet her @nicolekarlis.

MORE FROM Nicole Karlis

Related Topics ------------------------------------------

Daylight Saving Time Reporting Standard Time