The Senate Just Voted for You to Get Less Sleep, Expert Says

The world’s greatest deliberative body skipped the deliberations on Monday afternoon and rushed to make daylight saving time permanent. The bill cleared the Senate without a hearing or debate — just a unanimous voice vote. “Let me make it clear to anybody who’s watching that they just saw this measure pass,” Sen. Sheldon Whitehouse (D-R.I.), one of the bill’s co-sponsors, crowed from the Senate floor. “We have just passed the bill to end the return from daylight saving time.”

The urge to end the biannual clock switch comes up like clockwork in each Congress, with each attempt backed by a coalition of strange bedfellows. The bill has long been a pet project of Sen. Marco Rubio (R-Fla.), whose state has already moved to adopt daylight saving time year-round but cannot do so without Congressional approval. “Pardon the pun, but this is an idea whose time has come,” Rubio said upon the bill’s passage yesterday. Sen. Ed Markey (D-Mass.), who pushed to extend the daylight saving time period in 2005, celebrated his win with a video of himself grooving to “Walking On Sunshine” outside the U.S. Capitol building. “More sunshine, better health, and the end of a tired tradition,” he wrote in a subsequent tweet.

A tired tradition, indeed: Roughly 75 percent percent of Americans want to stop changing their clocks, according to an October 2021 poll conducted by the Associated Press-NORC Center for Public Affairs Research. As for better health, however, the best available research on sleep and human circadian rhythms doesn’t bear that out, says Beth Malow, a professor of neurology and the director of the sleep division at Vanderbilt Medical Center. Malow gave testimony before a House Energy and Commerce subcommittee last week urging lawmakers to consider making standard time, not daylight saving time, permanent instead. “People are emailing me saying, ‘Yay, you testified and look what you did!’ ” Malow says of the Senate’s move. “Well, it’s the opposite of what I testified.”

Scientists broadly agree that switching the clocks back and forth leads to poor health outcomes. The shift affects both the amount of sleep and one’s ability to maintain a consistent sleep schedule, “which can have a detrimental effect on our overall health,” says Anita Shelgikar, an associate professor of neurology and director of the sleep medicine fellowship at the University of Michigan. But, like Malow, Shelgikar says that standard time, not daylight saving, should be the standard. “Permanent standard time best aligns our internal clock with sunlight, which has benefits for individual and public health,” Shelgikar says.

Standard time is the “more natural time,” Malow explains, because the additional sun in the morning tells human brains it’s time to wake up, while the lack of evening light encourages sleep. During daylight saving time, “you’re getting too much light in the evening and not enough in the morning,” she says, which particularly affects people who have to be at work and school early in the day. On average, people sleep 40 minutes less per night during daylight saving time, says Erik Herzog, a chronobiologist at Washington University in St. Louis. “That’s a big deal, and a lot of people discount that.”

The shift in time isn’t only about sleep, Herzog adds. “You have a daily rhythm in every hormone in your body, independent of whether you’re sleeping or not,” he explains. Humans’ natural internal clock is a little longer than the Earth’s 24 hours, and “that light in the morning is really important for the human circadian clock to adjust to the 24-hour clock.” Otherwise, people experience circadian disruptions correlated with many negative effects. Herzog notes studies indicating higher rates of cancer and obesity in people who live at the western edges of time zones, who already suffer from some aspects of this. Encouraging that circadian disruption all year long could compound those negative health consequences. “Think of it as being a shift worker for your whole life,” Herzog says.

Should the Senate’s bill become the law of the land, its places like Rubio’s Florida that stand to gain. “It’s a state at the start of a time zone and as far south as you can get, so the sunrise and sunset times don’t vary as much,” Herzog explains. So, too, would the golf lobby, which has long viewed a bump in afternoon sunlight as a boon for the industry. But teenagers would be chief among the victims, Herzog says, because their brains require morning sunlight to wake up. People who live in northern states, where the sun rises later, would also struggle. “It’s a very different scenario depending on where you live,” Herzog says. As for the political incentives, “it boils down to economics — not health, not safety, not crime,” he adds.

Early indications suggest the bill won’t have such an easy time clearing the House. Several lawmakers, such as Rep. Fred Upton (R-Mich.), prefer legislation that would allow states to opt into permanent daylight-saving shifts. Rep. Debbie Lesko (R-Ariz.), whose state does not currently observe daylight saving time, raised concerns about how Arizona’s construction workers already take pains to avoid afternoon heat, which permanent daylight saving time, she argued, could worsen. “Please don’t mess with Arizona, we’ve been doing this for 40 years,” she said during last week’s hearing. (Sen. Kyrsten Sinema, for her part, appeared to exclaim “Oh, I love it,” upon the Senate’s passage of the bill, Politico reported.)

Rep. Jan Schakowsky (D-Ill.), who chairs the House subcommittee that held last week’s hearing, shared concern about clock-switching but voiced ambivalence over whether daylight saving time or standard time should be made permanent. The Chicago area, which Schakowsky represents, wrestles with its own time zone woes: Chicago and its suburbs across Illinois and Indiana are on Central time, while much of the rest of Indiana is on Eastern time. In a statement to Rolling Stone, Schakowsky said “there are many reasons we should seriously consider this” and that she will work with her subcommittee colleagues “to determine our next steps.” The House has not yet announced any plans to take up the Senate’s bill.

Experts now hope the House will take its time to think through the health consequences. “I feel like people voted for it and didn’t really understand it,” Malow says. “They were buying into the idea that they weren’t going back and forth anymore.”