What Should We Actually Do With Daylight Saving Time?

Summer is firmly in the rearview window, and the Sun is noticeably winding down earlier in the evening. On November 1, most of the United States and parts of Canada will change the clocks to ward off these later sunsets. Specifically, we’ll move back an hour and leave Daylight Saving Time for Standard Time, only to do the reverse come next spring. It’s a twice-yearly ritual that many people tolerate, but few enjoy.

A poll last year, from the AP-NORC Center for Public Affairs Research, found that only 12% of Americans liked the current system of switching clocks twice a year, while 47% outright opposed it (40% were neutral). A different YouGov poll earlier this March found that 64% of U.S. adult citizens were in favor of abolishing the clock switch, while only 16% wanted to hold onto it. And most countries in the world no longer even bother with the time switch.

Things get a bit trickier when trying to figure out how to end this practice, though; that is, whether we should permanently enshrine DST or Standard Time.

Some researchers and organizations have long argued that permanent Standard Time would be better, citing numerous studies suggesting that the switch to DST can have noticeable, if subtle, negative effects on our health, particularly our sleep patterns. Yet lawmakers have often pushed for permanent DST instead. Earlier this year, for example, President Donald Trump endorsed the Sunshine Protection Act, a bill that passed through the U.S. House of Representatives in July but has been stalled in the Senate ever since, following pushback from some Republican senators.

That same YouGov poll, by the way, showed that Americans seem to currently prefer permanent DST over permanent Standard Time, 43% to 28%. Perhaps surprisingly, both Republicans and Democrats support perma-DST by a similar margin.

Given our political gridlock, Daylight Saving Time will probably return next year. But it sure does seem like clock changes will soon sunset for good. Maybe. So for this Giz Asks, we reached out to experts to get their take on whether we should get rid of the clock switch and how it should be done. The following responses have been edited for grammar and clarity.

Ashtaad Dalal

A family and sleep medicine doctor, speaking on behalf of the American Academy of Sleep Medicine (AASM).

The best course of action would be to eliminate the twice-yearly clock changes altogether. The question is: which time standard would best support public health and well-being? From a sleep medicine perspective, it’s clear that permanent standard time is by far the healthier option.

“Fall back” means returning to standard time. “Spring forward” means switching to DST. Twice a year, we adjust our clocks and expect our bodies to follow suit. Yet our internal biological clocks do not reset as easily as our phones or computers.

Our bodies operate on an approximately 24-hour circadian rhythm that regulates sleep, alertness, hormones, metabolism, and cardiovascular function. Light is the most powerful environmental cue for synchronizing this system. Morning light helps align our internal clock with the day, while exposure to light later in the evening can delay the natural timing of sleep. Standard time better aligns with our underlying biology.

The health consequences of disrupting that alignment deserve attention. The spring transition to daylight saving time eliminates an hour of sleep overnight and abruptly shifts our daily schedules. Studies have associated this transition with increased rates of heart attacks, strokes, and hospital admissions. Research has also identified increases in motor vehicle crashes and workplace injuries around the clock change.

The concern extends beyond the twice-yearly transitions. Permanent daylight saving time would leave winter mornings darker, potentially requiring people to wake up, commute to work, and send children to school before sunrise. Insufficient morning light can delay circadian timing, while later evening light can make it difficult to fall asleep at an appropriate hour. Over time, chronic circadian misalignment has been associated with cardiometabolic problems, including cardiovascular disease and metabolic syndrome.

We have already seen how difficult it can be to sustain this approach. In 1974, amid an energy crisis, the United States experimented with year-round daylight saving time. Public opposition grew as children waited for school buses and commuters traveled in darkness. Congress reversed course before the year ended. The experience underscored a basic problem: shifting the clock does not eliminate our biological need for appropriately timed light.

The AASM supports permanent standard time because it most closely aligns human circadian biology with the natural light-dark cycle. That recommendation is grounded in sleep science, not nostalgia or personal preference.

We routinely rely on science and human behavior to guide decisions that shape our daily lives and create systems that better serve people. Timekeeping should follow the same principle. We have the scientific evidence to make a better choice. Rather than repeatedly forcing people to adjust their sleep schedules, we should choose a time standard that best supports our biology.

Mehwish Sajid

A neurologist and physician at the Michigan Medicine Sleep Disorders Centers and Ypsilanti Health Center.

DST introduces a misalignment between the internal circadian rhythm (your internal sleep-wake drive) with the social clock. This misalignment is associated with risks to physical health and public safety. Losing one hour in the spring results in less exposure to light in the morning and greater exposure to evening light and can delay your internal clock.

Teenagers are known to have worsening sleep deprivation during the springtime transition. Adolescents and high school students are potentially more susceptible to the adverse effects of DST, given their early school hours and a natural tendency to maintain a delayed sleep schedule, which often culminates in a sleep-deprived state.

We have ample evidence demonstrating the harms of twice-yearly time switches, especially when we “spring forward” and lose an hour of sleep. The first few days following this springtime change are associated with an increase in heart attacks, strokes, and motor vehicle accidents. A reduction in sleep satisfaction and increase in daytime sleepiness are also reported. We believe this is secondary to acute partial sleep deprivation, increased sympathetic tone (higher blood pressure and heart rate), and release of proinflammatory cytokines.

Adopting a permanent option would reduce these harms. When we look at which form, DST or Standard, would be the preferred permanent option, there is clear, biologically aligned support for adopting permanent Standard time.

Jay Pea

An amateur astronomer, founder, and current president of Save Standard Time, a North American nonprofit organization established in 2019 to support permanent Standard Time.

We should ditch the switch, we should ditch DST, and we should fall back and forget about it and stick to standard.

Standard Time is the more honest clock, set more closely to the sun. I grew up in rural Iowa, my grandparents were farmers, and they taught me to tell the time looking at the sun; when it’s in the south at its highest point, that’s high noon, that’s 12 p.m., and you divide the hours from there. Standard Time approximates solar time to within 30 minutes, ideally. DST was invented as a trick to make people get up earlier.

When you turn your clock ahead and you spring forward, now you have your clock that is an hour fast. And when your clock is an hour fast, that means your alarm clock will sound an hour earlier than it did on Standard time. The reasoning is that, well, in the summer, the sun’s coming up earlier, so it doesn’t make any sense to be doing it right now in October. But it would be terribly nonsensical to be doing it all year round in the winter. Most work and school starts around eight o’clock in the morning in the US, and that is after sunrise year-round on Standard time. But if we were on DST, the sun would be delayed until after 8 a.m. for most of the winter, for three months or longer in most states. You’d even see sunrise past 9 a.m. in eighteen states if we were on permanent DST. And nobody is asking to get up earlier, nobody’s calling up his congressman and saying, “Hey, can you make my alarm clock sound an hour earlier? I want to wake up in the dark and brave those icy roads while I’m still half asleep.”

DST was invented over a century ago. There was Willem Willett, who was an architect who wanted to play more golf after work, and it was promoted by the golf lobby and by the shopping lobby because they thought, “Well, if we make people get up and go earlier, then they’re gonna have more time to spend money in the evening.” But it was originally sold to us as a way for winning World War I, to increase labor, and for saving energy.

We don’t have to keep this thing. It makes us sleep less, which hurts our productivity, our performance at school, and it increases our risks for fatal car accidents and chronic disease. When you’re having too little light in the morning, it’s harder to get up and go. And when you have too much light in the evening, it’s harder to fall asleep. All that leads to long-term wear and tear on the body.

As for why people want to keep DST, I do think some of it is that Standard is a boring name and Daylight Saving sounds more exciting. We’re gonna save that daylight. And there’s also an emotional attachment with summer. A lot of people say, “I don’t know how this works, but I know I like summer. I know I feel better in summer, so can’t we just keep that year round?”

Then there are lobbyists. When we had a hearing in 2025 before the Senate Commerce Committee, there was Dr. Karin Johnson from the AASM speaking up for permanent standard time, and then there was Mr. Jay Karen from the National Golf Course Owners Association saying that they would make more money with permanent DST.

Interestingly enough, Donald Trump, when he was president elect in 2024, he initially said we should eliminate DST, that it’s costly and inconvenient, and it only serves special interests. And he was right to say that. Unfortunately, in April of the following year, after the golf people testified for permanent DST, President Trump started saying we need permanent Daylight. Now, President Trump owns, I think, 11 or 12 golf courses in the United States, and 16 overall across the globe. So there might be a connection there.

I don’t think we should be having government put the thumb on the scale. And if we’re favoring evening businesses with permanent DST, then we’re going to be hurting morning businesses with that added darkness. Morning business matters, too. You need your school bus driver, your snow plow driver, the groundskeepers, the security guards, etc., to have that morning light. So I think the best objective way is to just set our clocks to the sun, which is Standard Time.

[Author’s note: William Willet advocated for DST in the early 20th century to play golf later in the day; and Donald Trump has shifted his stance on DST.]

Ashley Nixon

A sleep and circadian rhythm researcher at the University of Ottawa. Nixon is also a member of the Canadian Sleep Research Consortium.

For a long time, the debate around DST transitions has been about abolishing the twice-a-year switching of the clocks. With general agreement now that the switching should stop, the conversation has turned to which clock we should keep. Most sleep researchers would agree that standard time, which more closely matches the sun, is the healthy choice.

To clarify a few things up front, neither option gives us more daylight. The clock only decides when that light falls in our schedule. Permanent DST would move an hour of light from the morning to the evening, all year long. But research shows that morning light is crucial for our body clock, which tends to run slightly longer than 24 hrs. It needs something to reset it every day, and that something is morning light, which keeps it on track. On the other hand, evening light pushes it later. On permanent DST, we move morning light to the evening, so our body clock drifts later, and we want to go to bed later and wake up later. This drift creates a clock mismatch, since work and school times don’t change. This mismatch between our body clock and our social clock (the schedule set by school and work) is what researchers call social jetlag. Permanent DST would worsen this mismatch and result in ongoing sleep loss.

Permanent DST is especially troublesome for teens, night owls, and those who live on the western edge of a time zone. Teenagers’ body clocks shift later during puberty, but school still starts early. Night owls also experience this delayed bedtime but, for the most part, don’t have the luxury of waking up when their body needs to because of work, resulting in sleep loss. In cities on the western side of a time zone, such as Grand Rapids and Indianapolis, where the sun already rises later, permanent DST would push winter sunrise past 9 a.m. That means eating breakfast and going to school or work in the dark for months. In studies of people living on either side of a time zone border, those on the western side (later sunrise and sunset) slept less and had higher rates of obesity, diabetes, and heart disease. It is also well documented that sleep deprivation is linked to depression, some cancers, weakened immune function, and impaired attention and learning. It is thus no surprise that past attempts at permanent DST were reversed.

I understand why permanent DST is appealing for the additional evening light in the winter; however, the trade-off of sleeping less and its negative consequences may not be worth it. If we’re going to pick one time to keep year-round, it makes sense to choose the one that keeps our body clock and social clock aligned. Our bodies need to follow the sun, and standard time is the clock that keeps us in sync and helps us get the sleep we need.

Carla Finklestein

A professor at Virginia Tech’s Fralin Biomedical Research Institute and an expert in circadian biology.

We tend to argue about DST as though it were a scheduling preference, a matter of whether we’d rather have light in the morning or the evening. That framing misses what’s actually happening. We are not moving daylight around. We are moving ourselves, and our biology does not come along.

It helps to think of three clocks. There’s the sun clock, set by the earth turning. There’s the body clock, an internal timer running in essentially every cell we have. And there’s the social clock, the one on the wall that we all agree to live by. Under Standard Time, these three sit reasonably close together. When we spring forward, we move only the social clock, and the other two stay where they were.

What follows is a light problem more than a time problem. Morning sunlight is the main signal that holds the body clock to local time, and DST takes an hour of it away. The same shift hands us an extra hour of light in the evening, which pushes the clock later still. Both effects run in the same direction. The body clock drifts, mornings get harder, falling asleep gets harder, and because work and school hours do not move, the result is chronic sleep loss and a mismatch we call social jetlag. Populations carrying more of that mismatch show higher rates of diabetes, obesity, heart disease, depression, and some cancers. I’d phrase that carefully, since most of this evidence is observational and shows these things traveling together rather than proving one causes the other. The pattern across many populations is consistent enough to take seriously.

On the question of whether the harm comes from the switching or from which time we lock in, I’d say both, and they aren’t the same kind of harm. The spring transition produces a visible, short-lived spike. Sleep shortens, performance drops, heart attacks tick up in the days that follow. The deeper problem is the months afterward, when the body clock stays out of step with the clock on the wall. Ending the switch removes the spike. Locking in the wrong time leaves the chronic mismatch in place permanently.

Which is why permanent DST would be the worst available option. It would stretch the misalignment across winter, when mornings are already dark and getting up is already hard. We have actually run this experiment. The U.S. adopted permanent DST in 1974, support collapsed after a single winter of dark mornings, the promised energy savings never materialized, and Congress repealed it before the trial finished.

So, abolish the switch. Then settle on permanent Standard Time, which is simply the arrangement where the clock on the wall most closely matches the sun.

Patricia Lakin-Thomas

An expert on biological clocks and circadian rhythmicity at York University in Toronto, Canada.

We should definitely scrap the practice of switching clocks twice a year. And when I’m speaking, I’m speaking on behalf of the Canadian Society for Chronobiology, of which I’m a board member, and I am also speaking on behalf of a consortium of scientific societies across Canada who are sleep researchers, there’s a sleep consortium. And this is also the consensus opinion across North American scientific societies and European scientific societies.

We’re all agreed that switching clocks twice a year is the worst system of dealing with the time problem. And we know this because we can see increases in acute health events and accidents in the spring.

When we spring forward, we are losing an hour of sleep. And we’re all sleep deprived anyway, so that’s bad for us. Plus, we’re moving out of what we would consider more natural Standard Time and we’re moving into DST. So after the spring switch, we see increases in acute events like heart attacks and strokes, and we see more car accidents and industrial accidents. But we don’t see those increases in the fall, when we fall back into Standard Time and we gain an hour of sleep. Our circadian clocks are better aligned with the sun time and our wake-up times, and we don’t see those effects of increased acute health events and accidents.

That tells us it’s not just the irritation and disruption of changing a clock that’s harmful, but that it really matters what direction you’re going when you change the clock.

So the conclusion should be: Get rid of the switch and have it be year-round Standard Time.

Jessica Farrell

An assistant professor of biomedical sciences at Northeast Ohio Medical University who has studied how time changes affect our circadian rhythms.

Most of us recognize the immediate effects of DST in the spring because we feel abrupt changes in our sleep and alertness. The springtime switch to DST results in an average loss of 40 minutes of sleep, which affects reaction times and levels of stress hormones like cortisol. In the immediate days following the clock change, traffic accidents, workplace accidents, and hospitalizations due to heart attack and stroke increase. These negative effects only occur during the “spring forward” entry to DST and are reversed when we “fall back” to Standard Time.

What many people don’t realize is that DST negatively affects our health in the long-term. Early morning light is the most important “wake-up” signal for our internal circadian clock. During DST, our exposure to this signal is delayed by 1 hour. Conditions like Seasonal Affective Disorder (SAD) would affect more people, and those already experiencing SAD can expect worsening symptoms. Similarly, the late sunsets of DST delay the release of melatonin and other hormones, causing us to sleep less from March to November. Lack of morning light, extra evening light, and sleep loss combined can make us feel groggy in the morning, with reduced focus, reduced productivity, and impaired reaction time throughout DST.

Both history and science show us that permanent DST would be even worse than the seasonal clock changes we observe now. The United States adopted permanent DST in 1974, with much of the public supporting the change. However, the later sunrises caused by observing DST during winter increased morning traffic accidents and deaths, including 8 children whose deaths were attributed to going to school in early morning darkness. Public support plummeted, and after only 6 months permanent DST was reversed back to the seasonal DST we observe now.

Related to health, we know that DST not only causes us to sleep less, but it shifts the timing of our sleep and makes it harder to fall asleep and wake up on time. In the first few weeks of DST, we lose anywhere from 25 to 60 minutes of sleep each night, and there’s an ongoing average sleep loss of about 19 minutes per night throughout DST. While this sleep loss may seem small, certain populations are more vulnerable to sleep deprivation, including children and teenagers. Permanent DST would extend this sleep loss year-round and lead to even further detrimental effects: risk of developing cancer, obesity, high blood pressure, and heart disease are all increased with chronic sleep deprivation.

Medical and scientific evidence overwhelmingly points to Standard Time as the preferred permanent option. Permanent Standard Time is endorsed by the National Sleep Foundation, the Sleep Research Society, the American Academy of Sleep Medicine, the National Safety Council, and the National Parent-Teacher Association, among many other reputable organizations.

It’s also the easiest option because Congress already permits states to opt out of DST and adopt permanent Standard Time at any time. Permanent Daylight Saving Time is federally prohibited and requires rewriting or repealing the Uniform Time Act. Most people want to end seasonal clock change, and restoring permanent Standard Time can be done immediately and without wasting legislative effort and taxpayer dollars.

Emily Manoogian

A chronobiologist and senior staff scientist at the Salk Institute for Biological Studies.

Changing our clocks twice a year disrupts sleep and increases health and safety risks. I think we all agree that switching our clocks is annoying and we want it to stop. But ending the clock changes is only part of the issue. We also need to choose the right time to switch to, and that is Standard Time.

Light is the primary cue our bodies use to tell time. Morning light helps align our circadian rhythms with our daily schedules, supporting sleep and daytime alertness. Light later in the evening can delay those rhythms, making us ready for sleep later. When school and work still require us to wake at the same time, that can mean less sleep. The timing of light matters for our health, and Standard Time provides a better alignment between our biological clocks and our work and school schedules.

The spring clock change provides a clear example of the risks of disrupting this alignment. A study of more than 730,000 fatal crashes found a 6% increase in fatal crash risk during the workweek after the spring transition, representing an estimated 28 additional fatal crashes each year. The increase was greater in the morning, and the study found no corresponding increase after the fall return to Standard Time. Studies have also reported increases in heart attacks after the spring transition.

One of my biggest concerns about permanent DST is what it would mean for winter mornings, particularly for children. Sunrise would be an hour later on the clock. In parts of Michigan, sunrise on January 10 would be after 9:30 a.m. under permanent DST. Many more of us would wake up and commute in the dark, and our children would be walking to school, waiting for buses, and even starting classes before sunrise. Permanent DST would also work against efforts to support adolescent sleep through later school start times by shifting morning light an hour later. We already tried year-round DST in 1974. Dark winter mornings were so unpopular, particularly because of concerns about children traveling to school, that Congress restored winter Standard Time that October, less than ten months after the experiment began.

Golf course owners and convenience-store industry groups have supported daylight saving time because later evening light creates more opportunities for recreation and spending. Those industries’ economic benefits do not outweigh the health and safety concerns associated with darker mornings. Permanent Standard Time would eliminate seasonal clock changes while preserving earlier winter morning light. It is the better choice for sleep, health, and the children and adults who need to start their day early.

As we turn our clocks back this fall, we have an opportunity to think beyond the next time change. Adopting permanent Standard Time would put sleep, health, and safety first—not just for one season, but year-round.

Giz Asks is a recurring Gizmodo series in which experts answer big questions in their own words, offering a range of perspectives on the ideas, discoveries, and debates that affect our lives and shape our understanding of the world.