Study suggests most Americans would be healthier without daylight saving time (2025)

https://med.stanford.edu/news/all-news/2025/09/daylight-saving-time.html

by andsoitis • 23 days ago

112 149 23 days ago

med.stanford.edu

kgwxd• 23 days ago

Assuming they don't get hit by a car walking to school.

_ZeD_• 23 days ago

And the rest of the world people? would it be healthier? the doubt is striking me

plugger2• 23 days ago

I live in Western Australia. for 3 years we trialed DST from 2006 to 2009. It was a nightmare personally, I was a sysadmin at the time and enterprise management tools were expensive and crap so we had to roll out DST file changes across our fleet manually. And because the change to allow DST for our region was a rushed job we then had to roll back after the 3 year unsuccessful trial.

Honestly, it was super stressful at the time. And DST that doesn't exist doesn't bother you in the slightest. Every day ends and flows into the next like the last. But the stress of a clock change twice a year doesn't have to happen, it's a choice.

ssl-36• 23 days ago

The US extended DST by 4 weeks in 2007. We managed that well-enough. We can manage a similarly-sweeping change again.

(Sorry about your nightmare. It was easy on the systems I took care of at that time.)

mikestorrent3• 23 days ago

Are you Yanks seriously not going to get this sorted out before winter? BC has moved - can at least the rest of Cascadia get their asses in gear? Come on, California, I do not want to be dealing with a north-south time zone difference with my coworkers

frollogaston4• 23 days ago

Then get BC to change it back

mikestorrent3• 22 days ago

Hell no. Never going back.

ssl-36• 23 days ago

Yes, we won't. It turns out that we're way too terrible at being rational way too much of the time.

For DST in particular: Even discussions where the participants manage to form something resembling a quorum to stop changing the clocks twice every year somehow manage to unilaterally get sucked into a seemingly-inescapable quagmire of differing opinions, wherein: The decision of whether to use standard time and stick with it or to stick with DST instead becomes an intractable impasse.

Accordingly, nothing ever gets done.

I have every expectation that I will be dead and buried before this issue is resolved.

evilfred• 23 days ago

I think US states aren't allowed to switch unless the feds decide to allow it

kortilla4• 23 days ago

Arizona doesn’t have it

mixologic• 23 days ago

US States aren't allowed to have permanent DST, but they can have permanent standard time.

wpm3• 23 days ago

Tough shit. I live on the eastern edge of Central Time, I don't want to be dealing with 3PM sunsets in December.

mikestorrent3• 22 days ago

Who gives a shit what time it happens at? It's not like you're actually making the day shorter or longer, man.

nerdsniper2• 23 days ago

We don’t really get much of anything sorted these days.

kuboble2• 23 days ago

I really wonder about the methodology. The article didn't mention it.

Did they get several cities to participate?

sixothree2• 23 days ago

I really don't want the sunrise time to be 5:00 in the morning and still not have any daylight to do errands after work. I don't care what the reasons are, but if seasons change the sunset time, what's so wrong with changing it a bit more?

NoGravitas3• 22 days ago

Why do you need daylight to do errands?

sixothree2• 22 days ago

And why do you ask stupid questions?

One of my errands is usually spend an hour in the park. I don't really need daylight for that. But I without DST I would have the daylight available but allocated incorrectly. Who wants incorrectly allocated daylight?

kubb• 23 days ago

This isn’t going to get fixed in my lifetime, and that’s sad. Countries have lost the ability to act.

JauntyHatAngle• 23 days ago

Plenty of countries have moved away from DST. Over half who previously used it IIRC.

lnsru• 23 days ago

Please name some of these countries. Europe is stuck with this nonsense and there is no hope in sight despite yearly polls showing majority people being against it.

keiferski3• 23 days ago

Of all the things that cause obesity and sleep loss, is an hour change twice a year really a major issue?

MisterBastahrd• 23 days ago

It's an extra hour of potential outdoors activity before nightfall. Yes.

keiferski3• 23 days ago

Do you think the average person is already spending the maximum amount of time outdoors to begin with?

pimlottc• 23 days ago

I don’t know, maybe someone should do a study on it.

kortilla4• 23 days ago

“This stupid thing we do that is worse for society than the perceived upsides is only twice a year. Why not keep doing it anyway?”

scns• 23 days ago

There are measurably more heart attacks and traffic accidents after the switch.

keiferski3• 23 days ago

Which switch? 1918?

pseudalopex2• 23 days ago

Some researchers found heart attacks rose a little after clocks were set forward and fell a little after clocks were set back. Other researchers found no significant change.

b112• 23 days ago

"Study by people who hate daylight savings time and have great bias against it, suggests that..."

andrepd• 23 days ago

the researchers estimate that permanent standard time would result in some 300,000 fewer people having suffered from a stroke and result in 2.6 million fewer people having obesity

That 2.6 million people are obese because of a 1h shorter change night in one Sunday a year is an extraordinary claim. I would love to understand how they got to this result.

userbinator• 23 days ago

It was tried 52 years ago, and no one actually liked it, so we went back to DST again:

https://en.wikipedia.org/wiki/Permanent_time_observation_in_...

Possibly another example of the old Chesterton's Fence.

tumult• 23 days ago

No, that’s describing permanent DST, which was tried and failed, not lack of DST. Most people in the world live without DST and it’s fine. (The article also mentions this.)

tristanj12• 23 days ago

The majority of the planet do not live at higher latitudes, where implementing adjusted summer/winter hours actually makes sense.

reedf111• 23 days ago

Except it's not like Chesterton's fence, it was created at the edge of living memory for known reasons. If anything it's an example of the opposite effect, something like Chesterton's field, do we really need to build a wall here, it's been a field for a damn long time...

tristanj12• 23 days ago

Do the anti-DST people understand what they're advocating for?

Have a look at the sunset/sunrise graph for northern parts of the US https://www.timeanddate.com/sun/usa/seattle

In Seattle, without DST, sunrise happens at 4:11am. Because of DST, it's pushed back an hour later to a more reasonable 5:11am.

I am not awake at 4am, I have no use for sunlight at 4am, and I don't want the sun appearing that early. That hour of early sunlight is wasted for me. Plus with DST, the sun sets an hour later, at 9:11pm, a time I am actually awake, and I can actually go outside and use the extra sun.

And, with permanent DST (which is what many people are advocating for), then in winter sunrise is at 9am in Seattle, which is far too late. I do not want to drive to work in the dark, before sunrise. So I want standard time in winter, pushing sunrise an hour earlier to a more reasonable 8am.

In both situations (summer and winter), modifying the time via DST benefits me and gives me better use of sunlight.

snowe2010• 23 days ago

Yeah, it’s insane. Along with that, any permanent gains in the morning will be lost as soon as it becomes normal. Businesses will just open that much earlier. And this study assumed bedtimes of 10pm, which is not the average anywhere on the planet from what I remember the last time I looked into this. The average is like past midnight.

wpm3• 23 days ago

More tyranny inflicted upon the rest of us by morning people

devilbunny2• 22 days ago

The average is like past midnight

Jesus, for what age group?

I'm an outlier because I have to be at work at 6:30 AM daily (so I get up around 5:15), so staying up past 10 PM is a rarity and I see midnight maybe two or three times a year. I don't think I've slept past 8 AM in the past decade, even on vacation. But I haven't even frequently stayed up past midnight since my mid-twenties, and even then didn't do so every night. I'd have been too sleep-deprived.

kortilla4• 23 days ago

This just seems like a backwards justification. There is nothing wrong with a 9am sunrise or a 4:11am sunrise. People in Anchorage deal with both just fine.

I am not awake at 4am, I have no use for sunlight at 4am

Most people aren’t awake at 5am either. Your use for the sun when there is an excess of it that goes well past your bedtime if you get up at 5am is irrelevant.

suddenlybananas2• 23 days ago

4am sunrise seems ludicrously early to me, but then again, even a 5am sunrise is awfully early.

tristanj12• 23 days ago

My work starts at 9am, therefore I wake up around 7am. My work start time does not adjust based on the seasons. Any sun before 7am is wasted for me.

Under DST, at summer solstice, the sun rises around 5am, giving me 2 hours of wasted sunlight.

Without DST, at summer solstice, the sun rises around 4am, giving me 3 hours of wasted sunlight.

I enjoy having additional hours of sunlight when I am awake, so for me I actually prefer having DST vs without it.

Similarly, in the wintertime, under permanent DST, sunrise is around 9am, and I don't want to drive to work in the dark.

toxik3• 23 days ago

I can see the DST argument for people where the shift kinda sorta works out, but many places (like Anchorage!) it's completely unnecessary. I live in Sweden and it's just the twice annually "ah shit the clock moved overnight."

AngryData3• 23 days ago

Why should the clock be set to those arbitrary points? If you want sun in the morning, wake up later, it you want sun in the evening, wake up earlier.

If your issue is when work is scheduled, well businesses set their own hours, not the government.

jonplackett• 23 days ago

Businesses don’t care how much sun you get

user43928• 23 days ago

Working hours will not change.

I will fight tooth and nail against attempts to take one hour of daylight from me in the evenings for half of the year.

seanmcdirmid3• 23 days ago

Then we should have timezones based not just on longitude, but also latitude. So northerly locales can get some sleep in the spring/summer/fall.

If your issue is when work is scheduled, well businesses set their own hours, not the government.

Ah, someone who doesn't have kids in school/camp/some random activity yet.

We know how this goes in China (one time zone, no daylight savings time). Coming home from the bar in Beijing with the sun showing up at 4 AM was quaint back then, but I'm definitely glad we have DST in the states.

artisinal2• 23 days ago

businesses set their own hours, not the government

In plenty of countries the government decides the opening hours of shops, restaurants and sometimes even offices. Labour laws and nighttime pay are coupled to the hours on the clock. Hours you can make noise is decided by government. Germany has the mid-day resting hour (Mittagsruhe).

sokoloff2• 23 days ago

The government sets the hours of the schools, which in turn drives the schedules of a fair chunk of society.

reedf111• 23 days ago

Hol up, don't fix time, there's a few guys in Seattle without curtains. Sorry everyone.

pseudalopex2• 23 days ago

Curtains would make the sun set later in summer and rise earlier in winter?

zokier3• 23 days ago

You realize that you can change your own sleep patterns seasonally if you want to? Heck, you could do that even gradually instead of those abrupt 1 hour changes. That is your choice, we don't need to fiddle with clocks for the whole society for that.

tchalla• 23 days ago

You can have your own household clock.

ekidd2• 23 days ago

Yeah, as someone who lives in Vermont, you could talk me into permanent DST. That would move the winter sunset from, say, 4:21pm to 5:21pm, which would mean I'd get enough twilight for a short walk after work. And Maine is even further east and north in the same time zone, so they have an even earlier sunset. On the other hand, Vermont's standard time sunrise around 7:20 is reasonable enough.

Parts of Vermont have traditionally coped with this by having an 8-4 workday instead of 9-5.

But the reality is that Vermont gets only about an hour of daylight outside working hours, depending on local customs. People have extremely strong preferences about how that hour gets split up.

jsdalton• 23 days ago

Permanent DST is just a synonym for "let's all agree to wake up an hour earlier." The same change could be affected by e.g. schools and businesses agreeing to open at 8am instead of 9am. (Of course that would be wildly unpopular so permanent DST is just way to trick people into swallowing the pill.)

But would behavior change in the long run? Countries like Spain where solar noon differs wildly from clock noon just end up aligning their rituals accordingly (e.g. eating dinner at 9pm).

gspetr2• 23 days ago

Do the anti-DST people understand what they're advocating for?

They do, which is why only 45 countries observe DST.

25 observe it partially.

And the rest, roughly ~125 countries do not.

Historically, ~140 countries did.

To put this into perspective, only about 1.2B people out of 8.3B observe it today. Which puts you into a very small <15% minority.

tristanj12• 23 days ago

Appealing to population is a stupid argument. DST as a policy is designed for places at higher latitudes, and the the majority of the planet do not live at higher latitudes. DST exists to maintain a more consistent time of sunrise across seasons.

DST is moronic in any part of the world close to the equator. There is not enough seasonal adjustment in the time of sunrise to justify adjusting the clocks. And in places of the world such as the middle east, they have an active policy of avoiding the sun and a policy of DST (which maximizes sunlight while awake) is antithetical to how society functions.

YossarianFrPrez• 23 days ago

Between this and the "Sunset time and the economic effects of social jetlag: evidence from US time zone borders" paper [0], it seems like the issue is the size of the discontinuous jump in time, not necessarily that we change the clocks. So why not "smear" the DST<=> ST transitions by having four half hour transitions, once each quarter?

[0]https://pubmed.ncbi.nlm.nih.gov/31030116/

raz32dust• 23 days ago

If you present this as the alternative, I think there's a chance people might actually just get rid of it :)

ssl-36• 23 days ago

I like where this is heading.

To that end, I'd like to propose 12 transitions. These should happen on the 16th day of every month, at precisely 05:14:33.

Let's take our seasonality more seriously.

JoshTriplett• 23 days ago

So why not "smear" the DST<=> ST transitions by having four half hour transitions, once each quarter?

Very easy answer: Because it's already painful twice a year, and that would be making it even worse.

That answer is similar to the one for questions like "why do we have wide time zones that are somewhat inaccurate, rather than setting every clock based on the exact position of that clock?".

nerdsniper2• 23 days ago

I’d be okay with every day having a different # of seconds. That way we slowly adjust with no discontinuity, but the nominal start time of school/work stays the same.

While this feels would be a disaster for other reasons like: “How many seconds are in an hour?” -> “Depends, no one knows.” … that’s already the case with our existing leap seconds.

sharts• 23 days ago

Every few years these studies are published. Nothing changes. Unfortunately policy isn’t dictated by science, facts, or optimal outcomes for all.

anal_reactor2• 23 days ago

My controversial idea: midnight should be where current 4AM is because 04:00 is the lowest point of human circadian rhythm. Currently we have nonsense like "1AM is technically a part of the next day but for all practical purposes it's still the previous day". Also, 24h clock should be the standard so that we can avoid discussions "is 12AM noon or midnight".

ButlerianJihad2• 23 days ago

I live in a hot desert climate where most of the daytime during summer is inhospitable to human activities.

We also do not observe DST at all, and that makes us a red-headed stepchild in America.

I have longed for a system here where summertime means a 12-hour DST: everyone sleeps all day and then goes to work/school in the coolness and darkness of nighttime. I absolutely love chilling outside in the dark when the lows are in the 70s, 80s.

https://m.xkcd.com/2594/

Time zones were invented because of railroads, and all of the time/date related troubles we have today is because modern urban technology is 100% fake artifice that denies the contours of the natural world, not to mention globalism that denies contours of local culture and seeks to cram everyone and everything into rigidly defined boxes.

NoGravitas3• 22 days ago

I live in a hot desert climate where most of the daytime during summer is inhospitable to human activities.

I live in a hot/humid subtropical where most of the daytime in summer is likewise inhospitable to human activities. I too long to be nocturnal in summer, though here it doesn't cool down as much at night.

frollogaston4• 22 days ago

I don't understand how Arizona lives during the day for like 5 months. It's too darn hot there, and because it's dry, nighttime is way cooler.

rrrrrrrrrrrryan• 22 days ago

In Japan, if you get on a 1 hour train just before midnight, the printed ticket will say something like "23:05" for the embarkment time, and "24:05" for the disarmament. Same date for both - the clocks can just go beyond 24 hours.

Spend enough time out late in Japan, and you'll see hour 24, 25, even 26.

reedf111• 23 days ago

It's pretty astounding to me the number of pro-DST advocates in this forum. If you had hundreds of daily jobs on your platform and you happen to have some regular requirement to change them in unison, if a junior engineer said "let's just change the system clock to adjust for when we want the jobs to run", you would say no, because while it might be easy compared to changing the config for each of the jobs, the risk of ongoing errors, side effects, introduction of jobs that need to fixed in absolute time that you have to make the inverse change... It's a system nightmare.

artisinal2• 23 days ago

That is why you run your jobs on GMT/UTC and not display time.

edoceo2• 23 days ago

The jobs need to run at midnight, local time. Which shifts from UTC. How to handle?

reedf111• 23 days ago

I guess that is what I'm trying to show in the above example. You could technically shift your UTC jobs by running your own NTP server and desyncing it from UTC by the offset you want. It would work, but it would be nightmare fuel. And possibly this is an even better example of what DST is doing.

kuboble2• 23 days ago

Well, it's not that obvious.

Some jobs should run every day at 8 am (e.g. torn on the temporary speed limit on front of the school), vs tasks that should actually run every 24h (e.g. feed the bacteria in exact time intervals)

f33d5173• 23 days ago

It's a fairly trivial change. We already have timezones, which exist to deal with the fact that the sun comes up at different times in different parts of the world. We already have to design everything around the assumption that timezones can change, since people sometimes move to different parts of the world. All we do is cause, for an entire timezone, that it becomes a different timezone at one point in the year, and switches back later. This ensures that the sun continues to come up at a consistent time. The main issue it causes is to make the lives of programmers slightly more difficult, which I am sure they can cope with...

anal_reactor2• 23 days ago

Imagine having a solution that already works with changing system clock but then some very big very important very senior very developer shows up and launches a multi-year project to redesign this, potentially opening pandora box of endless bugs. PhD in Job Security, typical shit I see in corporate.

reedf111• 23 days ago

To be clear if I showed up to a company running their own company NTP server that they desync twice a year to make timings work - I would absolutely try to migrate them away from that. Now if they are doing that there is probably bigger fish to fry... but it would be on the list.

smitty1e• 23 days ago

Everybody's "Blatantly Obvious To A Casual Observer" (BOTACO) solution is somebody else's "Scam Amounting to Large Amounts of Dollars" (SALAD).

fmajid• 23 days ago

Thee golfing industry is one of the big proponents of keeping DST and lovbbies hard for it.

apexalpha2• 23 days ago

I live in the Netherlands.

In the summer the suns up at 5 am. But at 5am I am asleep. I could get up earlier but that's pointless since school and work doesn't start until 8.30.

So in stead of having an hour of sunlight before school and work we all change our clocks to have an hour of extra sunlight in the evening in stead, which fits our cultural preference for social activities.

We could also, as you say, change every single sign, post and display of opening hours for every school, business and organisation at the same time to achieve the same effect.

But in the real world changing the clock is simpler.

literalAardvark• 23 days ago

So change it... just permanently. GMT+2 will always be there for you.

tanin• 23 days ago

With DST, there are actually 2 new concepts: ambiguous time (if the clock rolls back) and invalid time (if the clock jumps forward).

Java and Ruby work differently. Java would simply round the invalid time to the closest valid time IIRC. Ruby would accurately raise the InvalidTime exception. Same behaviors for an ambiguous time.

Chile is actually the country that will cause tricky issue in a system because they adjust DST at midnight... so there is one day a year where its midnight is considered invalid time. If we are building a system that depends on a day's boundary, then we will encounter this nightmarish issue where one of the days must start at 1am instead of midnight.

I really hope DST is going away soon.

Fizz43• 23 days ago

This is so much effort for next to no gains.

fragmede2• 23 days ago

Oh my God, just move it by half an hour permanently!

tristanj12• 23 days ago

That doesn't fix anything, the reason DST exists is because at higher latitudes, the sun rises too early in the summer, and too late in the winter. DST exists to make the time of sunrise more consistent across seasons. DST only functions if hours are shifted seasonally, once for summer, and again for winter.

Have a look at a sun graph to understand why https://www.timeanddate.com/sun/usa/seattle

fragmede2• 22 days ago

What? It fixes everything! It means you never have to change times again. That singular benefit overrides anything else. what's wrong for summer is right for winter, and vice versa, but if it's equally bad it's also equally good.

NoGravitas3• 22 days ago

Honestly, I hate daylight savings time because I don't get enough night. I like being awake at night, but I also like going to bed pretty early. Winter is fine, but summer is bad enough without layering DST on top of it.

thegrim33• 22 days ago

The topic always feels like a typical propaganda push to me; the constant sensationalist articles, people constantly bemoaning it when in reality having to change your clocks by an hour twice a year is the most trivial, irrelevant thing to spend any energy/attention caring about, but I can't for the life of me figure out what the propaganda angle actually is. How does some group benefit from getting rid of it? Or is the negative messaging, creating an us-vs-them argument about even the most random of issues, increasing conflict/division in society, the angle, and they don't even care about getting rid of it?

tsoukase• 22 days ago

Even in Southern Europe the winter day is 2+2 hours less than the summer. Not only I am PRO-DST but I advocate for a full two hour change. It's not 20th century any more. Most jobs start later, people want to enjoy after job and LEDs offer bright light if needed. Tell the Spaniards where the sun sets later that the Dutch.

SAI_Peregrinus• 21 days ago

DST is bad because it changes the clocks in huge jumps. Very poor for people's health. Noticeably increases excess deaths.

Fixed clocks are bad because they don't track the sunlight.

We should change the clocks by 10 minutes, every month. Keep dawn at roughly the same time every day, say 06:30. Add enough time zones so that dawn will always be within 10 minutes of 06:30 at the equator for a given longitude.

Study suggests most Americans would be healthier without daylight saving time (2025)

Related Stories