In October 1973, five oil-producing countries imposed an embargo on oil exports to the United States, causing gas prices to soar. Scarce supplies led to long lines at filling stations. The economy slid into recession.
On November 7, President Nixon proposed emergency measures that included year-round daylight-saving time, which the Interior Dept. estimated would conserve the equivalent of 95,000 barrels of oil per day. Congress quickly approved the time change. America moved clocks ahead one hour on January 6, 1974, with a plan to keep them there for two years.
Within weeks, however, public opinion had soured on winter Daylight Saving Time. (It’s “saving” although it’s often pronounced “savings.”) It was judged a failure and abandoned. This debacle, mostly forgotten today, is of more than historical interest now, as the nation ends daylight saving time and returns to standard time on Sunday, November 1.
Now, the idea of observing DST year-round—permanently, this time—is gaining ground across the nation, even though history and recent scientific discoveries suggest we would be better off ditching DST completely and sticking to standard time. Nevertheless, 13 states from Florida to Washington have enacted legislation since 2018 to put themselves on permanent DST. At least 26 more states were considering the move this year.
None has been able to put it into effect, however, because it’s not an option under the Uniform Time Act, which established national DST in 1966. Until then, states and even cities decided what the time would be within their jurisdictions, resulting in all the inconsistency and confusion you would expect, particularly for railroads, which pushed for uniformity. The 1966 law imposed order by allowing states to stay on standard time, like Hawaii and most of Arizona do, but requiring states that opt for daylight saving to observe it on the same schedule, which Congress has gradually lengthened to eight months, March to November.
To the rescue has come Sen. Marco Rubio of Florida. His Sunshine Protection Act would put an end to changing clocks twice a year anywhere in the U.S. The bill also would advance each U.S. time zone by one hour. Presto! The equivalent of daylight time becomes the new national standard, year-round.
Rubio’s bill has attracted bipartisan support in Congress. Joe Biden has not staked out a public position, but President Trump tweeted his endorsement, for what that’s worth. And although Rubio’s bill has languished in a Senate Commerce subcommittee without a hearing, the well-hydrated senator is undaunted. In September, he introduced a bill to extend DST temporarily until November 2021 as a COVID-19 relief measure. “Our government has asked a lot of the American people over the past seven months,” he tweeted, “and keeping the nation on Daylight Saving Time is just one small step we can take to help ease the burden.”
Rubio’s persistence may pay off in the long run. As more state legislatures register a preference for year-round DST, pressure may build on Congress to act. But the arguments commonly made for permanent DST rest on dubious assumptions, cherry-picking of evidence, and outright distortion. Supporters of permanent DST can sound like they’re recruiting for a cult. They promise longer days, less energy use, improved moods, diminished crime.
A brief on Rubio’s Senate website, for example, claims delaying sunset with DST “reduces car crashes and car accidents involving pedestrians,” ignoring studies that found the opposite. A 2017 review of two dozen studies concluded that the accumulated research “should not be used to support or refute the assertion that shifts in time-zones can have a road safety benefit.” Similarly, Rubio says year-round DST “benefits the economy” by boosting consumer spending. As evidence, he cites a JP Morgan Chase study that actually concludes the data “does not support consumer spending claims of DST advocates.”
As we’ll see, advocates also ignore recent scientific discoveries in neurobiology and epidemiology—findings that have led many scientists to conclude DST is bad for our health and would be even more so if observed year-round. Also conveniently overlooked are the lessons from past experience with year-round DST.
Seasons in the Sun
Moving clocks forward in 1974 was intended to conserve energy, but results in this regard were paltry. Subsequent research has confirmed that the energy saved during DST is minimal.
Ineffectiveness, however, was not the biggest problem with DST in the winter of ’74. The biggest problem was immediately apparent because almost nothing else was visible. “Daylight Saving Puts Most in Dark as Week Opens,” read the headline on the New York Times story about the first weekday of daylight time, or rather no-daylight-in-the-morning time:
Commuter trains from New Jersey were delayed, many school children missed their free breakfasts, some workers walked to subways and buses with trepidation, and many people felt strange yesterday as the day began an hour earlier for most in eerie darkness.
Sunrise was delayed everywhere, but the change must have been especially jarring in northern latitudes, where winter days are shorter, and on the west side of time zones, where daybreak is later. January sunrise did not arrive until about 9 a.m., daylight time, across much of the Upper Midwest and Pacific Northwest. Two days into DST, The Seattle Times ran a front-page photo of students arriving for school in darkness. The caption: “It Seems Like Night School.”
Even in the South, winter DST soon was blamed for almost every pedestrian traffic accident in the a.m. A Florida TV commentator dubbed it “daylight disaster time” after eight children in the state, far more than in the same period a year earlier, were struck and killed in roadway accidents as they walked to school in the winter gloom. Across the country, morning mishaps sparked public anxiety and prompted many schools to delay their start times, upsetting parents’ schedules.
Few saw much compensating benefit in the afternoon, as the winter sun still set before 6 p.m. in most places. By early February, many governors were calling for the repeal of year-round DST. Congress relented. The U.S. returned to standard time in autumn and resumed switching to and from daylight time seasonally.
This turnabout should not have been too surprising in light of the nation’s one previous experience with year-round DST. Americans put up with it during World War II as one more sacrifice needed to help defeat the Axis powers. But there was no support for continuing War Time, as it was called, in peacetime. Congress repealed it a few weeks after V-J Day.
Outside the U.S. also, year-round DST has been tried and abandoned. Britain experimented with it in the late 1960s, but Parliament voted 366 to 81 to return to seasonal DST after complaints from groups that spend early mornings outdoors—such as farmers, builders, and postal workers—and from Scotland, where sunrise came latest. In 2014, opposition from northern regions similarly prompted Russia to renounce year-round DST after three years.
Which raises the question: Why, despite its history of failure, is permanent DST suddenly a U.S. trend?
Walking on Sunshine
The idea has a superficial appeal. The annual onset of DST heralds the approach of longer days and better weather. Why not enjoy more of it all year?
Advancing clocks by one hour does not protect sunshine, of course. Daylight saving doesn’t even save daylight but delays it. (Although as a brand, “daylight delaying time” lacks something.) Extending the time change to winter will not make the season less cold and dark.
The most compelling argument for year-round DST—and the primary impetus for legislation, other than annoyance over the chore of changing clocks—has to do with health problems associated with the spring onset of DST. A shocking array of problems—such as sleep deprivation, heart attacks, stroke, inflammatory bowel diseases, and even suicide—all apparently increase after clocks spring forward, but not after they fall back in autumn. These vernal problems are reasons to “ditch the switch,” say proponents of year-round DST. They blame the springtime clock change, which deprives us of an hour’s sleep.
Yet, while some of these problems dissipate a few days after the time change, others linger at elevated rates long past March, which suggests that our bodies never fully adjust to DST. Based on a growing body of research in neurobiology and epidemiology, a scientific consensus has emerged that time switching, although irksome, is less problematic than DST itself. “It’s not one hour twice a year. It’s a misalignment of our biologic clocks for eight months of the year,” says Beth Ann Malow, professor of neurology and pediatrics at Vanderbilt University.
Time Out of Time
In the 1970s, scientists knew little about circadian rhythms. Seasonal affective disorder, for example, was not identified in the scientific literature until 1984. Now, we know it can arise from reduced exposure to morning light in winter. Exposure helps wake us up by suppressing the hormone melatonin, which makes us sleepy, and elevating the hormone cortisol, which keys us up to meet the day’s challenges.
Because delayed sunrise can prolong elevated melatonin levels, scientists worry permanent DST would spread and intensify sleepiness, winter blahs, and seasonal depression. High cortisol levels, postponed by delayed sunrise and prolonged by later sunset, could at least partially explain why the start of DST in the spring brings a rise in reports of disturbed sleep. “We have an epidemic of sleep deprivation, and daylight saving time makes it worse,” says Nathaniel Watson, professor of neurology at the University of Washington.
Other problems also may be linked to circadian disruption caused by DST. Biologic clocks regulate our physiology and influence our behavior in innumerable ways. Among the most important: body clocks control immune response and DNA repair, both crucial to getting and staying well. Recent research has shown that these processes can be impaired by things like jetlag and what physiologists call social jetlag, such as working the night shift, sleeping in late on weekends—and DST.
Its abolition is now recommended by a growing chorus of scientific societies. The American Academy of Sleep Medicine published a position statement on the subject in October. “Permanent, year-round standard time is the best choice to most closely match our circadian sleep-wake cycle,” said lead author M. Adeel Rishi, a specialist at the Mayo Clinic.
The scientific case against DST also is detailed in a position paper adopted in June 2019 by the Society for Research on Biological Rhythms, an international organization of scientists and clinicians. Even deeper dives, drawing the same conclusions, were published in 2019 in the journal Frontiers of Physiology and by an international panel of nine scientists in the European Journal of Internal Medicine.
The fundamental idea is that we tend to do well when our body clock and social clock—the official time in our time zone—are in synch. That is, when noon on the social clock coincides with solar noon, the moment when the Sun reaches its highest point in the sky where we are. If the two clocks diverge, trouble ensues. Additional, startling evidence for this has come from recent findings in geographical epidemiology—specifically, from mapping health outcomes within time zones.
Time is on My Side
Time zone borders are drawn inconsistently, often according to political boundaries and patterns of commerce. But U.S. zones are each roughly 15 longitudinal degrees wide, so that the Sun, as it appears to travel from east to west at a rate of one degree every four minutes, passes over one zone per hour and reaches its highest point above the middle of a zone around noon, standard time, in that zone.
The synchronization is imperfect. Toward a zone’s eastern edge, solar noon will tend to arrive a little before noon, standard time. Toward the western edge, the opposite; solar noon—and body clocks, therefore—will lag a little. But by and large, U.S. zones are configured to keep body clocks and the social clock in close harmony.
On standard time, that is. On DST, not so much.
DST shifts the social clock forward an hour for most of the year, leaving solar noon lagging behind, especially on the west side of time zones. For example, in Detroit, on the western edge of the Eastern time zone, solar noon lags even on standard time, but DST widens the gap. If DST were year-round, Detroit would never see solar noon before 1:15 p.m. and some days not until 1:46 p.m.
Here’s why this matters: Scientists say lagging body clocks, left behind by DST, are why people living on the west side of U.S. time zones, like Detroiters, tend to be less healthy, have higher cancer rates, and die sooner. (Of course, Detroiters and Michiganders have contended with everything from lead in the water (Flint) to homicides (Detroit) to deindustrialization (pretty much statewide). Still, health status gets progressively worse, no matter what city, the farther west it is within a zone.
Many studies have confirmed this finding nationwide. “Risk increased from east to west within a time zone for total and for many specific cancers,” concluded scientists at the National Cancer Institute in 2017. The reason is “circadian misalignment,” said a team of Harvard public-health researchers in 2018.
One way such circadian disruption may make people sick is through sleep deprivation, a known killer. The Sun sets last on the west side of time zones. Later sunsets may prompt people, via hormonal and social cues, to stay up later. And they may then sleep less overall, as work and school have set start times in the morning. Indeed, economists who analyzed data from the Bureau of Labor Statistics, which collects detailed diaries of how Americans spend their time, found those living on the west side of time zones get an average of roughly 115 hours less sleep per year.
Bear in mind that if delayed sunsets do trigger a cascade of ill effects, then west-siders are the most affected, but not the only ones. Pushing off sunset for everyone, wherever we live, is the whole point of DST.
Which is bad news especially for night owls—what physiologists call late chronotypes, whose body clocks lag more than most and lag even more during DST. Researchers suspect this is why night owls are less healthy than morning larks/early chronotypes.
Teenagers, too, may be especially vulnerable. Research has found they tend to be night owls because their melatonin kicks in later in the evening. To counter chronic sleep deprivation in students, many schools have delayed their morning start times—in effect, moving the school clock back. But DST negates this move for five months of the school year. Year-round DST would negate it all year.
Time After Time
The scientific case against DST has emerged mostly in the past few years, and lawmakers considering the issue seem to be blithely unaware of it. Hearings tend to be cursory, maybe because year-round DST usually has no fiscal impact and because it is moot unless and until Congress acts. Debate tends to be lighthearted, even flippant. The Salt Lake Tribune reported on preliminary approval of a permanent DST bill in the Utah Senate:
Monday’s 28-1 vote followed a brief and semi-serious debate, in which senators questioned whether setting a consistent time year-round would affect the growth of flowers, dedicated their votes to individual constituents, warned against the health dangers of traveling between time zones, and asked whether passing the bill would end what has become a perennial debate on Capitol Hill.
“If we pass this, can you guarantee us it will stop coming back every session?” said Sen. Todd Weiler, R-Woods Cross.
As the U.S. moves toward advancing clocks permanently, the biomedical evidence has Europe headed in the opposite direction. In 2019, the European Union voted to scrap summer DST after three scientific societies jointly urged the adoption of year-round standard time.
Scientific opinion may carry less weight in the U.S. But if permanent DST goes into effect, the smart bet is that it will prove temporary. As in 1974, its popular appeal will not survive winter. And once the unpleasant reality of it hits again, Americans may decide to pay more attention to our body clocks than to politicians’ fads.