Daylight Saving Time: Should We End It?

Daylight saving time is ending, and the darkness is coming for us all. And many of us dread this time of year; we think that switching up our clocks sucks. But beyond that, we hear that all this clock changing can be bad for our health, contributing to stuff like heart attacks. So, should we ditch these annoying switches altogether? And if we do that, which way should we go: daylight saving time all year, or standard time?? We look at the science and talk to wildlife ecologist Prof. Laura Prugh and sleep scientist Prof. Jamie Zeitzer. Find our transcript here: https://bit.ly/ScienceVsDaylightSavingTime In this episode, we cover: (02:15) Why do we have daylight saving time? (05:25) What happens when we “fall back” (14:15) Is daylight saving time bad for our health? (27:00) What should we do? This episode was produced by Michelle Dang, with help from Rose Rimler, Meryl Horn, Ekedi Fausther-Keeys, and Wendy Zukerman. We’re edited by Blythe Terrell. Our executive producer is Wendy Zukerman. Mix and sound design by Bobby Lord. Fact checking by Erica Akiko Howard. Music written by Peter Leonard, Bobby Lord, So Wylie, Emma Munger and Bumi Hidaka. And a special thanks to researcher Dr. Aiste Steponenaite, who also spoke to me for this episode. Science Vs is a Spotify Studios Original. Listen for free on Spotify or wherever you get your podcasts. Follow us and tap the bell for episode notifications. Learn more about your ad choices. Visit podcastchoices.com/adchoices

• 0:00Speaker 00

  Hi, I'm Michelle Dang, filling in for Wendy Zukerman this week. And you are listening to Science vs.

• 0:07Speaker 00

  Today, we're pitting facts against falling back and springing forward.

• 0:17Speaker 00

  Pretty soon, a lot of us will be changing our clocks by an hour. And with this biannual ritual comes a chorus of haters. Daylight savings time needs to die.

• 0:28Speaker 01

  Twice a year, I have to mess with my life and move the clock by one hour because of daylight saving time.

• 0:33Speaker 02

  I hate daylight savings. I just would like to have a moment of silence for how much daylight savings [BLEEP] up your day.

• 0:40Speaker 00

  A lot of people think it's time to say goodbye to these shifts. In fact, a handful of countries have already abolished the switches. And while in the US, hundreds of bills have been proposed to do the same.

• 0:53Speaker 03

  There's a new push in Congress to lock the clocks and stop our spring and fall tradition altogether.

• 0:59Speaker 04

  Senate unanimously approving a proposal to make daylight saving time permanent.

• 1:05Speaker 00

  So, a lot of people want to quit changing the clocks, but there's a lot of debate. Like, yeah, having that sunlight in the evening after work is really nice, but people are saying it's bad for our health, even dangerous. That daylight saving time could even kill you.

• 1:22Speaker 05

  Did you know the number of heart attacks increased right after daylight saving changes? Having to wake up in the dark is not only uncomfortable, it's actually really bad for your health long term.

• 1:33Speaker 00

  So today, we're looking at the science of springing forward and falling back and asking, should we get rid of these clock changes once and for all? And if so, what's better for us? Permanent daylight saving time or permanent standard time?

• 1:51Speaker 00

  Because when it comes to the switches, there's a lot of... Daylight savings time needs to die. But then, there's science.

• 2:02Speaker 00

  Science vs. Daylight Saving Time is coming up after the break.

• 2:12Speaker 06

  Are you looking for support in your weight management journey? Zepbound Terzepatide may be able to help. Zepbound is a prescription medicine used with a reduced calorie diet and increased physical activity to help adults with obesity, or some adults with overweight who also have weight-related medical problems, to lose excess body weight and keep the weight off. Zepbound is approved as a 2.5, 5, 7.5, 10, 12.5, or 15-milligram injection. Zepbound contains Terzepatide and should not be used with other Terzepatide-containing products or any GLP-1 receptor agonist medicines. It is not known if Zepbound is safe and effective for use in children. Don't share needles or pens, or reuse needles.

• 2:54Speaker 06

  Don't take if allergic to it, or if you or someone in your family had medullary thyroid cancer, or if you've had multiple endocrine neoplasia syndrome type 2. Tell your doctor if you get a lump or swelling in your neck. Stop Zepbound and call your doctor if you have severe stomach pain or a serious allergic reaction. Severe side effects may include inflamed pancreas or gallbladder problems. Tell your doctor if you experience vision changes before scheduled procedures with anesthesia. If you're nursing, pregnant, plan to be, or taking birth control pills. Taking Zepbound with a sulfonylurea or insulin may cause low blood sugar. Side effects include nausea, diarrhea, and vomiting, which can cause dehydration and worsen kidney problems. Talk to your doctor.

• 3:34Speaker 06

  Call 1-800-545-5979, or visit zepbound.lily.com.

• 3:43Speaker 07

  Gray roots entering the chat, uninvited? Garnier's got you. Garnier Color Sensation Root Retouch covers up to 100% of grays in just 10 minutes. No ammonia, no mess, and the color lasts up to four weeks. It's as easy to apply as shampoo. Plus, it's vegan and cruelty-free. 10 minutes. Sensational color, sensational price. With those savings, your next girls' night is basically free. Find your perfect match at walmart.com or at a store near you.

• 4:16Speaker 00

  Welcome back. Today on the show, daylight saving time. Is it bad for us and should we get rid of it? I'll be discussing the science today with senior producer Merrill Horn. Hey Merrill.

• 4:27Speaker 08

  Hey Michelle.

• 4:28Speaker 00

  Are you ready for the fall switch?

• 4:31Speaker 08

  Not at all. I hate daylight savings time.

• 4:35Speaker 00

  What part do you hate?

• 4:37Speaker 08

  Mostly because I have two small kids. It's like you spend all this time trying to make their bedtimes like, you know, go well and get them up for school at a certain time. And then it's like you suddenly remember, oh crap, like everything has to happen differently tonight. And either try to keep them up late or try to put them down early, which never works. And it's just a mess for that first few days.

• 5:01Speaker 00

  You don't think you get that extra hour of sleep in the fall switch?

• 5:04Speaker 08

  No.

• 5:06Speaker 00

  So Merrill, like, why do you think we have daylight saving time in the first place?

• 5:10Speaker 08

  I mean, I've heard it's because of the farmers, something to do with the farmers.

• 5:14Speaker 00

  Because I also heard that before. Interestingly, it has nothing to do with the farmers.

• 5:19Speaker 08

  Uh huh.

• 5:20Speaker 00

  But it actually started as a government project to save energy.

• 5:24Speaker 08

  Huh.

• 5:25Speaker 00

  And it was back during the World War I years.

• 5:28Speaker 08

  Wait, so it's only, it's only been around since World War I?

• 5:32Speaker 00

  Yeah, it was like conceptualized before that, but the first country to like widely adopt it was Germany as a way to save fuel during wartime efforts.

• 5:42Speaker 08

  Why would that save fuel?

• 5:44Speaker 00

  Like if you can extend the day and the sunlight, you can then save costs on working into the night.

• 5:49Speaker 08

  Oh.

• 5:50Speaker 00

  Like light and energy.

• 5:51Speaker 08

  Okay.

• 5:52Speaker 00

  Other countries in Europe then picked it up, and so did the US, which finalized the national schedule for it in the 60s.

• 5:58Speaker 08

  Okay.

• 5:59Speaker 00

  But the, the kind of funny thing is that these days, daylight saving time doesn't save that much energy.

• 6:06Speaker 08

  Oh.

• 6:06Speaker 00

  So like one report from 2008 found that we save half a percent of electricity per day of what otherwise would have been used.

• 6:15Speaker 08

  Oh.

• 6:16Speaker 00

  And other studies find it doesn't save energy at all.

• 6:19Speaker 08

  Once we realized that the fuel thing didn't make sense, why did we keep it? Is it just kind of tradition?

• 6:24Speaker 00

  Yeah, so there's been some other big arguments to keep it. One was the economy. Like this idea that if there's more light out in the evening, that people are more likely to go shopping, do their errands.

• 6:36Speaker 08

  Oh, that kind of makes sense. Like stores are open later in the summer in my neighborhood.

• 6:40Speaker 00

  Yeah, and interestingly, like, retail golf and sporting goods industries have all been big advocates for daylight saving time, as well as Halloween candy makers.

• 6:52Speaker 00

  Like, they really wanted daylight saving time to go over, like, trick-or-treating hours.

• 6:58Speaker 08

  So that people would be trick-or-treating in the light when it's like they can get more hours out of trick-or-treating.

• 7:04Speaker 00

  Yeah, yeah, yeah.

• 7:04Speaker 08

  Does it actually help the economy?

• 7:07Speaker 00

  So there are studies on this too, and it's also, it's mixed whether it actually helps or not.

• 7:14Speaker 08

  Even though the business people think it helps, it's not that clear that it's that good overall for businesses.

• 7:20Speaker 00

  It could be helping particular industries, right, but as a whole for the economy, it's pretty mixed. Okay, so now that we know that the original reasons for daylight saving time don't make sense, let's find out if we should just get rid of it. Like, is daylight saving time actively causing harm to us? And I want to start with where we are now in the US, about to fall back. So meet Laura Prue. She's a scientist at the University of Washington, and like you, she finds the fall switch pretty annoying.

• 7:52Speaker 09

  Especially in Seattle, when it's dark and rainy at that time of year anyway, having it start to get dark at like 3:30 is really tough. You know, at the end of your workday, you leave work and, oh my god, it's dark out already.

• 8:09Speaker 00

  Yeah, it's so depressing. Yeah, I know, like, sad we were just working for eight hours, but then everything we do after work is then in darkness. And a big part of our evening is our commute's home, you know, going to the grocery store, getting kids to school activities, meeting friends. So traffic volume is definitely busier in the evening than in the morning.

• 8:31Speaker 00

  And this is where daylight saving time really intersects with Laura's work. Because she is a wildlife ecologist. But one of the species that she studies is deer.

• 8:41Speaker 08

  Oh.

• 8:43Speaker 00

  You know, there are tons of deer across the entire US. And sure, they're cute, but they can also be kind of a big problem for us because we're always out there hitting them with our cars.

• 8:54Speaker 08

  Yeah, I feel like this is not gonna end well for the deer.

• 8:58Speaker 00

  Have you ever had any run ins with deer?

• 9:00Speaker 08

  No, but it's so scary. I know people who have and it's so dangerous, like for everybody. If there's an accident with one, so it does freak me out.

• 9:10Speaker 00

  Yeah, yeah. In the US, we hit a ton of deer with our cars, more than 2 million a year.

• 9:18Speaker 08

  Whoa.

• 9:18Speaker 00

  And that's just like what's reported. And most of the time when we hit them, it's dark out, like at dawn or at dusk.

• 9:26Speaker 08

  Because that's when the deer are like out and about?

• 9:30Speaker 00

  Yeah, there's actually a word for when animals are on this kind of schedule. Here's Laura.

• 9:35Speaker 09

  It's one of my favorite terms. It's called crepuscular.

• 9:39Speaker 00

  Crepuscular?

• 9:40Speaker 09

  I really like that. Crepuscular, yes.

• 9:42Speaker 00

  That is a nice word. Crepuscular. Crep- I can't say it. Crepuscular. I think I'm still saying it wrong.

• 9:51Speaker 08

  Okay, and that literally means that you're more active when it's dawn and dusk?

• 9:57Speaker 00

  Yes, and so like these are the times when it's darker out. It's harder to see them. And those accidents can be really bad. Not just the deer, but the people involved too. Like every year in those accidents, almost 60,000 people get hurt.

• 10:12Speaker 08

  Whoa.

• 10:13Speaker 00

  And more than 400 people die.

• 10:15Speaker 08

  Wow.

• 10:16Speaker 00

  You know, fun fact, maybe not a nice fact, but this is the mammal in the US that's responsible for the most human deaths.

• 10:23Speaker 08

  What is deer?

• 10:25Speaker 00

  Yeah.

• 10:26Speaker 08

  That is, that's a fun fact, I'm sorry. So it's actually a really big problem. It's like if there was another animal that was killing that many humans, we would be like up in arms about this.

• 10:38Speaker 00

  And so to connect this back to daylight saving time, when it gets darker earlier, that means a lot of us are commuting when it's darker as well. And in the fall, there's this other thing that's happening for the deer. They are actually busy getting it on.

• 10:52Speaker 09

  Oh. So the rut is their mating season? And they are just jacked up on hormones. The males, the bucks are just running around looking for females and they're not paying as much attention. They're moving a lot more.

• 11:11Speaker 08

  Oh no, so they're like even more active when the change is happening.

• 11:16Speaker 00

  Yeah, Laura said that some studies find that deer are moving up to 50% more this time of year. And Laura was like, with all that going on and adding the fact that it's getting darker earlier, is that causing us to hit more deer? So she and her team decided to look into this and they started scraping national and state databases on car collision reports.

• 11:38Speaker 09

  So we ended up collecting records of over a million deer vehicle collisions across 23 states.

• 11:49Speaker 00

  Laura and her team wanted to know like the time, the date, and the location of these accidents to see like how the number of collisions change the week after daylight saving time ends. Okay, so here's Laura.

• 12:03Speaker 09

  Suddenly now the evening rush hour is more in the dark when it's much harder for us to see the deer. And that really causes the collision rates to spike. What we found was that that switch in the fall led to a 16% increase in collisions just comparing the week before the switch to the week after.

• 12:28Speaker 08

  Oof, okay. Well, so there's one reason that we shouldn't be doing this. Because that means theoretically then more people are also dying. If there's more accidents overall.

• 12:39Speaker 00

  Yeah, Laura and her team were thinking, they were like, what would happen if we just got rid of the switch?

• 12:44Speaker 08

  Yeah.

• 12:45Speaker 00

  What if we did daylight saving time all year round? So we had more light in the evening all year round. Like how many more deer collisions would that prevent? So they did a bunch of math on that and estimated that having permanent daylight saving time could prevent over 36,000 deer car accidents a year across the US.

• 13:06Speaker 08

  Whoa.

• 13:07Speaker 00

  And she calculated that would mean 2,000 fewer injuries and 33 fewer deaths.

• 13:12Speaker 08

  What?

• 13:14Speaker 09

  Yeah, I was surprised because, yeah, I thought it would just be a kind of a, maybe a little blip. But we, yeah, we found it was a pretty substantial effect.

• 13:28Speaker 08

  That's huge. That's like, I mean, for those people that would make, obviously make a huge difference. That's pretty strong evidence, I feel like, to just keep daylight savings time.

• 13:39Speaker 00

  They also found that if we had permanent daylight saving time, that it would save us $1.2 billion from those accidents, but total cost of medical bills and repairs. And it's not just about the deer here in the US, in case you were wondering. The same thing is true in Australia for koalas.

• 13:59Speaker 08

  Oh, no, the koalas get hit by cars?

• 14:03Speaker 00

  There were some researchers from Queensland, Australia, that found that fewer koalas would get whacked if they went to permanent daylight saving time.

• 14:12Speaker 08

  Wow, okay. Though, I mean, I hate to sound like this, I'm skeptical that like hitting a koala would kill as many people as hitting a deer. Sad to think about, but it seems like they just kind of squish under your car.

• 14:26Speaker 00

  Oh, yeah, I know. And another big argument is that less crime happens when it's later out in the evening. Like, there was one study that found that in the US, robberies decreased during daylight saving time. In the evening hours, robberies went down by 27% when you compare daylight saving time to standard time.

• 14:47Speaker 08

  Oh, that makes sense, yeah.

• 14:50Speaker 00

  Bottom line for Laura, though, is that we should just really get rid of the switch. And she's a proponent for moving to permanent daylight saving time all year round.

• 14:59Speaker 09

  Like, there's just, in my opinion, a lot more costs to, to switching human lives and thousands of injuries.

• 15:09Speaker 00

  Okay, so that's some of the big players in team daylight saving time all the time. Less accidents with deer and less crime.

• 15:17Speaker 09

  Mm-hmm.

• 15:17Speaker 00

  What do you think overall? Are you currently convinced that we should stay on daylight saving time?

• 15:22Speaker 08

  Yeah, I feel like we should, that's what I would pick. I'm more of a night person than a morning person. I'd rather have the sunlight after work.

• 15:32Speaker 08

  And I hate that the switching itself is such a pain. I don't see why we don't just do it all year round now. Let's do it.

• 15:41Speaker 00

  I've only told you part of the science here. There's a whole other field of scientists that say we should have standard time all year instead.

• 15:50Speaker 08

  What? Why? Why would anybody want the darkness all year round?

• 15:54Speaker 00

  We're going to get into that after the break.

• 16:12Speaker 10

  This episode is brought to you by Chase Sapphire Reserve. On this podcast, we sort fact from fiction. So here's a quick truth for you. With Sapphire Reserve, you can spend all around the world. Not only that, but you can earn four times the points on flights and hotels, book direct, and three times the points on dining. Plus, enjoy access to award-winning airport lounges and exclusive restaurant tables. Learn more at chase.com/sapphirereserve. Cards issued by JPMorgan Chase Bank, N A member, FDIC. Subject to credit approval; terms apply.

• 16:50Speaker 11

  Reimagine how you do wellness with new first-of- their-kind Mochi Bites from the number-one gummy supplement brand, Ollie. Multi-beauty, energy, and sleep Mochi Bites are certified vegan, gluten-free, made with naturally sourced sweeteners, delectably tasty, and take your routine from mundane to extraordinary, all while delivering the same expert benefits. Elevate your wellness with Mochi Bites today. Sold exclusively at Target. These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.

• 17:20Speaker 12

  This episode is brought to you by Petivity. Cat parents are basically mealtime detectives. Who actually ate? Did they finish? Was that less than yesterday? The new Petivity Smart Feeder for cats turns everyday meals into meaningful health insights, helping you identify changes in your cat's habits and be more proactive about their health. Plus, you can feed them from anywhere. Take the mystery out of mealtime. Visit petivity.com, P E T I V I T Y dot com slash cat feeder to learn more.

• 17:49Speaker 06

  Are you looking for support in your weight management journey? Zepbound Terzepatide may be able to help. Zepbound is a prescription medicine used with a reduced calorie diet and increased physical activity to help adults with obesity, or some adults with overweight who also have weight-related medical problems, to lose excess body weight and keep the weight off. Zepbound is approved as a 2.5, 5, 7.5, 10, 12.5, or 15-milligram injection. Zepbound contains Terzepatide, and should not be used with other Terzepatide-containing products or any GLP-1 receptor agonist medicines. It is not known if Zepbound is safe and effective for use in children. Don't share needles or pens, or reuse needles. Don't take if allergic to it,

• 18:33Speaker 06

  or if you or someone in your family had medullary thyroid cancer, or if you've had multiple endocrine neoplasia syndrome type 2. Tell your doctor if you get a lump or swelling in your neck. Stop Zepbound and call your doctor if you have severe stomach pain or a serious allergic reaction. Severe side effects may include inflamed pancreas or gallbladder problems. Tell your doctor if you experience vision changes before scheduled procedures with anesthesia, if you're nursing, pregnant, plan to be, or taking birth control pills. Taking Zepbound with a sulfonylurea or insulin may cause low blood sugar. Side effects include nausea, diarrhea, and vomiting, which can cause dehydration and worsen kidney problems. Talk to your doctor. Call 1-800-545-5979, or visit zepbound.lily.com.

• 19:23Speaker 00

  Welcome back. I'm Michelle Dang, and today we're telling you about the effects of changing our clocks twice a year, here with Merrill Horn. So let's talk about another piece of this debate, the idea that switches are bad for our health, and that we should be on permanent standard time. This is the argument you hear a lot from people who study sleep. So this big idea that switches are bad for our sleep particularly has to do with that spring switch when we spring forward.

• 19:51Speaker 08

  Hmm.

• 19:52Speaker 00

  Because a lot of us lose an hour of sleep.

• 19:54Speaker 08

  Yeah.

• 19:55Speaker 00

  And sleep scientists say like that not only messes with you cognitively, but also can increase the risk of like heart attacks and strokes.

• 20:04Speaker 08

  Whoa, really?

• 20:04Speaker 00

  Yeah, you can hear this kind of thing all the time on the news.

• 20:08Speaker 13

  We'll lose an extra hour of sleep as we spring forward tomorrow. Research shows the bad news doesn't stop there. The risk for heart attack and stroke goes up in the first two days.

• 20:19Speaker 14

  The time change can cause an increase in heart attacks, strokes, car accidents, exhaustion, and depression. One hour.

• 20:25Speaker 15

  One hour is all it takes. That's how fragile and vulnerable your body is to even just the smallest perturbation of sleep.

• 20:33Speaker 00

  And the idea here is that some of this stuff might happen because you lose that hour of sleep and are more tired. But another worry is that daylight saving time goes on to screw with our circadian rhythm. And it's because of light. So in the morning, when the sun comes up and shines into your eyeballs, it sort of ends up screaming at the cells in your body to wake up. It gets us alert, pumps out hormones to get us going through the day. And the timing of all this really matters. I talked about this with Jamie Zeitzer. He's a sleep scientist from Stanford University.

• 21:08Speaker 16

  And that bright sunshine closer to when you wake up is, in theory, going to strengthen your circadian clock. And this is the clock in your brain that basically helps to synchronize all of your internal organs and all of your functioning to this 24-hour solar cycle that we exist in. So you've got all these other clocks in organs, right? You've got a clock in your liver, you've got a clock in your lungs, in your immune cells.

• 21:33Speaker 08

  Whoa, so the sunlight is sort of waking up all these cells inside your body?

• 21:40Speaker 00

  Mm-hmm. Yeah. I mean, most importantly, it's syncing up all these different systems in your body. And sunlight is the best source of like bright light that we can get for this kind of thing.

• 21:51Speaker 08

  Oh, and so like the, so the lights that we have in our houses, they're not strong enough to like synchronize everything together?

• 21:59Speaker 00

  Yeah, and Jamie told me that like a really well lit bathroom or kitchen is gonna be about 500 lux. Now, if you go outside, it's a nice day, bumps that up to 40,000.

• 22:11Speaker 08

  Whoa.

• 22:11Speaker 00

  And at noon, it's about 100,000.

• 22:14Speaker 08

  The sun is so bright.

• 22:16Speaker 00

  So that, that the sun is just giving out so much more than what you're getting inside.

• 22:21Speaker 08

  Oh, so maybe that's why I have a hard time waking up in the mornings, because I do not currently go outside first thing in the morning and expose myself.

• 22:30Speaker 00

  And the thing is that bright light is helping to signal the central circadian clock in your brain.

• 22:36Speaker 16

  You can kind of think of it like a conductor of an orchestra.

• 22:42Speaker 00

  And the cells and organs in your body are like sections of an orchestra. Like Jamie says, you've got the violins, the oboes, the flutes, and they need to be guided to start and stop their task at the right time.

• 22:54Speaker 16

  And that's basically what this central circadian clock is doing, is making sure everything, it's a strong conductor, and making sure all the instruments are synchronized with each other so that you have a beautiful tune. And early morning light exposure helps it not only know what time it is, but also helps it be a stronger conductor for this orchestra.

• 23:14Speaker 00

  Hmm, I'm assuming you know about that part of the brain, Merrill being the brain person, the brain scientist.

• 23:20Speaker 08

  The suprachiasmatic nucleus?

• 23:25Speaker 00

  Yeah, you're right. That is the suprachiasmatic nuclei.

• 23:28Speaker 08

  Hey, I still remember something from grad school.

• 23:32Speaker 00

  It's like this little itty bit of the hypothalamus.

• 23:35Speaker 08

  Yeah.

• 23:36Speaker 00

  That the, the eyes talk to.

• 23:38Speaker 08

  And that's like the conductor.

• 23:39Speaker 00

  Yes, yes. Now, Jamie says when you mess with your sleep schedule and light, the messier the orchestra can get, like the weaker your circadian rhythm can get.

• 23:52Speaker 16

  Now, if you have an erratic sleep-wake cycle, which really also translates to an erratic light-dark cycle. Then you get a weaker clock.

• 24:02Speaker 00

  So let me give you an example. Imagine we are in the spring.

• 24:06Speaker 08

  OK.

• 24:07Speaker 00

  And daylight saving time is about to start. You are used to waking up at 6:00 AM for work. And the sunrise used to be at 6:00, but now rises at 7:00, an hour later.

• 24:18Speaker 08

  Then you're...

• 24:19Speaker 00

  You're still waking up at 6:00 for work, but now in the dark.

• 24:22Speaker 08

  Mm-hmm.

• 24:22Speaker 00

  And Jamie says that means...

• 24:24Speaker 16

  You start poking the clock, right? And every time you're poking the clock, and when you have a weaker clock, it's like having again this weak conductor, and the organs don't work quite as well.

• 24:35Speaker 00

  The organs stop talking to each other as well. And so they stop working together as well as if they were nicely synchronized.

• 24:43Speaker 08

  Uh-huh.

• 24:43Speaker 00

  Like, imagine if I started missing all your work Slack messages.

• 24:47Speaker 08

  Uh-huh, like even more than usual, you mean, Michelle?

• 24:51Speaker 00

  Yeah, I guess I could use some morning sunlight, too.

• 24:58Speaker 08

  OK, but so, wait, what? So what's going on with our organs?

• 25:03Speaker 00

  OK, yeah, so this is where, when you have disruptive clock changes, it can start to affect your health. Because the circadian system does play a big role in almost all of your body's functions.

• 25:15Speaker 08

  Hmm.

• 25:16Speaker 00

  Like Jamie said, one area we have pretty good evidence is that affects your metabolism. So say, for example, your body has this ability to figure out how many calories you need, but...

• 25:26Speaker 16

  When your circadian clock is weaker, it's able to basically less accurately determine this. There is this connection between your metabolism and expectation of food when you're eating, how much you're expected to eat, and the circadian clock. So the way that you can see this most easily is lots of data looking at individuals who do shift work. You see much higher rates of obesity in people who end up doing shift work.

• 25:53Speaker 08

  But that's like an extreme situation. Like, we're not all suddenly like waking up in the middle of the night and working a night shift when that happens. It's only an hour and it's only twice a year. Like, I'm still kind of skeptical that there are negative consequences from just that one shift.

• 26:09Speaker 00

  Well, it's not just the switch itself that messes with our circadian clock. Another argument they talk about is this idea that standard time is just better for us in general.

• 26:19Speaker 08

  Right.

• 26:19Speaker 00

  That it's better for our clocks because it matches our so-called like natural states. Like, if we were living in a forest or something.

• 26:28Speaker 08

  Oh, OK.

• 26:29Speaker 00

  That it's kind of this like evolutionary argument that our bodies are built to wake up naturally with the sunlight.

• 26:37Speaker 08

  That you're waking as close to the sun as possible. That would happen more often if we stayed on standard time all year round.

• 26:43Speaker 00

  Yes, yeah. And they've also looked at societies of people who don't use artificial light, where they've studied their sleep cycle and they do wake up with the sun and wind down after that sun has gone down. And Jamie told me that because of this...

• 26:58Speaker 16

  There are a lot of people who are in the sleep and circadian fields who have been stomping their feet for years about how important it is to get rid of the switch and how critical it is to be in permanent standard time. And they have been very vocal about this.

• 27:15Speaker 00

  And maybe it's not exactly foot stomping, but the American Academy of Sleep Medicine, the Sleep Research Society, the National Sleep Foundation, all say we should be on permanent standard time.

• 27:26Speaker 08

  I guess, I mean, I can see why there's like a theory for why it would be important. I'm still not convinced yet that we have like cold hard evidence that this really makes it that much of a difference.

• 27:37Speaker 00

  Actually, Meryl, Jamie felt the same way. I asked him about this. Were you stomping your feet with them?

• 27:43Speaker 16

  No.

• 27:44Speaker 08

  What?

• 27:45Speaker 00

  Yes.

• 27:45Speaker 08

  So he's not one of them?

• 27:47Speaker 00

  Jamie's got some gripes with the it's more natural argument. And he says that a lot of sleep scientists were kind of just shouting about this like theory.

• 27:55Speaker 16

  That's what everyone's been saying. Oh, according to the theory, we should. Well, how about some data? This is what I've been saying for years is I'd like to see some data. And no one ever shows any data.

• 28:05Speaker 08

  Yes, exactly. Me too. Where's the evidence?

• 28:07Speaker 00

  Yeah, so Jamie went and got some. To see how big this impact actually is. Him and one of his grad students pulled together data on sunlight from all the counties across the contiguous US. Like when the sun rises and sets over a year. And then they basically wanted to see how much each mode of time pushes on the body's internal clock. So they took those times and.

• 28:31Speaker 16

  We put that into a model of the circadian clock and said, okay, we put into the clock. Here's the burden that we are pushing onto the clock in these three different time policies.

• 28:41Speaker 00

  And they based the model on kind of an idealized person who like has a nine to five, gets a well at office, but also gets sunlight in the morning and is outside in the evening. Then they took the numbers and matched it up to health data from the CDC for all of those counties. They wanted to see like which mode of time was the worst for our health. All your standard time, all your daylight saving time, or the switches like we have now.

• 29:08Speaker 08

  Okay, so this is to see like when your clock is kind of getting poked the most.

• 29:14Speaker 00

  Yeah, and Jamie saw that our clocks got poked the most with the switches, having to deal with adjusting the clock twice a year. And that that level of clock poking was linked to worse health.

• 29:26Speaker 16

  What you see is that as a whole, we do better without the biannual shift. We found it for two very specific things. We found it for obesity rates and strokes.

• 29:38Speaker 08

  Wow.

• 29:39Speaker 00

  Yeah, so those were the, like, out of like chronic conditions that they looked at from the CDC data, those are the two that stuck out and were significant.

• 29:48Speaker 08

  So if we didn't have those switches, we would see, we would actually see lower obesity rates and fewer strokes?

• 29:55Speaker 00

  That's what their model estimates, looking at just the effects of what's going on with our circadian rhythms. And so we talked about before, the metabolism mechanism that would have to do with obesity rates. They're not quite sure on the mechanism for strokes, but when you have a messed up circadian rhythm, it does affect things like your blood pressure, blood clotting and inflammation in your body. So those things might have to do with why a stroke could happen.

• 30:22Speaker 08

  So the switches, this is saying the switches are bad?

• 30:25Speaker 00

  Yes, the switches suck. And actually, what Jamie found was that both permanent daylight saving time and permanent standard time would be better than the switches.

• 30:34Speaker 08

  Huh.

• 30:35Speaker 00

  But between those two, there was a winner. The best one was, drumroll, standard time.

• 30:44Speaker 08

  No.

• 30:46Speaker 00

  Yeah, looking at obesity and strokes, standard time was the best.

• 30:50Speaker 08

  Okay.

• 30:51Speaker 00

  They found that if we stopped switching and stayed in permanent standard time and, you know, did a good job of getting exposed to light, we could potentially prevent obesity in over 2 million people.

• 31:02Speaker 08

  What?

• 31:02Speaker 00

  And prevent strokes in 300,000 people.

• 31:05Speaker 08

  What?

• 31:06Speaker 00

  Now, his study showed you could still avoid a bunch of cases of obesity and stroke if you had permanent daylight saving time all year, but not as many. Standard time still beat it out.

• 31:16Speaker 08

  Oh, man. So is he one of the foot stomper's now?

• 31:20Speaker 00

  I was curious about that, too. I mean, he was surprised.

• 31:24Speaker 16

  I went in very skeptical, thinking like, ah, we're not going to find anything. And couldn't disprove it. We kept on showing that this was real. And, and so that kind of, you know, that kind of convinced me that that there's something there.

• 31:38Speaker 00

  So Jamie's not a foot stomping kind of guy now, but he did come away acknowledging that there's some data here for team standard time. And by the way, Jamie's study didn't find an association with heart attacks in either of these long-term scenarios. There is a link you see in some earlier studies where more heart attacks occurred the week after losing that hour's sleep in the spring switch. But the effect size is pretty small. And another big study just came out that didn't see a link at all to the switch.

• 32:07Speaker 08

  OK, so but big picture here. What should we do then? Like, which side is the science pointing to?

• 32:13Speaker 00

  Yeah, it's like kind of funny. Like, I thought there'd be a clear answer here, but it's messier than I thought.

• 32:19Speaker 08

  It feels like we're stuck in limbo or something because everyone agrees that the changes themselves are bad, but we just like now can't decide on what we should stay in. Is that right?

• 32:32Speaker 00

  Yeah, and the US public is pretty mixed on all this, too. A couple of polls from earlier this year found different things. Like, one found that about half of people want to keep standard time all year round. But another found that half of the people want to keep daily saving time all year round.

• 32:48Speaker 08

  OK, so not that helpful then. Because like even if we got rid of it, which one would we go for?

• 32:55Speaker 00

  Meryl, if you were science advisor here, what do you think you'd do?

• 32:59Speaker 08

  OK, I think I have a solution. Can we just like split down the middle? Like, what if we, instead of picking an hour earlier or an hour later, we did like 30 minutes? Is that possible?

• 33:11Speaker 00

  Yeah, some scientists have actually brought this idea up, too. But, Meryl, could you imagine the logistics of being a half-hour offset from other countries? Could be kind of a headache. But places like India and parts of Australia have made it work, so.

• 33:26Speaker 08

  So what would you do, Michelle?

• 33:28Speaker 00

  Um, yeah, I honestly, I struggle with making a call because in real life, there's just so much variation in people's schedules. Like, in Jamie's study, the model was based on sort of this ideal person with an ideal light exposure. And a lot of us don't get that. So maybe the benefits of sticking on standard time would be smaller than what he found.

• 33:51Speaker 08

  Mm hmm.

• 33:52Speaker 00

  And then when it comes to you considering permanent daylight saving time, where you live matters a lot, too. Like, if you live on the western edge of your time zone, places like Indianapolis, Salt Lake City, Seattle, you could be looking at like 9:00 AM sunrises in the winter, which that would kind of suck, too.

• 34:10Speaker 08

  It's pretty late. Okay.

• 34:11Speaker 00

  Yeah, yeah.

• 34:12Speaker 08

  But you gotta pick a side. Like, it sucks now with the switches. There's gotta be, something's gotta be the best.

• 34:19Speaker 00

  So Meryl, I think, controversial take, but I think that we should stick with what we have now until the science is super clear.

• 34:28Speaker 08

  Even though we know the switches themselves are really bad?

• 34:31Speaker 00

  Yeah. I don't think, I don't think we actually know what the best option is yet, so. I'm kind of holding out.

• 34:39Speaker 08

  Ha, so you really want to see definitive science so that when we do finally like make this decision, we can be like totally confident that it's gonna make the most people happy? Is that what you're thinking?

• 34:52Speaker 00

  Exactly, yeah.

• 34:53Speaker 08

  Okay. But then what are we supposed to do in the meantime? Like, now that we know that the switches are terrible?

• 35:00Speaker 00

  Yeah, well, if you're worried about this messing up your sleep or your body, there is something you can do to make the switches easier.

• 35:07Speaker 08

  Oh.

• 35:07Speaker 00

  And, yeah, and that is to adjust your sleep time by 15 minutes a day the week before the actual switch.

• 35:15Speaker 08

  Okay.

• 35:16Speaker 00

  Basically ease into the switches so it's not a whiplash for your body.

• 35:20Speaker 08

  So we, like in this case, start trying to go to bed 15 minutes earlier, a few days beforehand, so that when the actual time change happens, our bodies will just slide right into it and be like, oh, this is totally okay. Okay, I could try that, I guess. It seems kind of annoying, to be honest, but.

• 35:38Speaker 00

  But anyway, Meryl, you have a few days heads up, so get on it tonight.

• 35:42Speaker 08

  All right, homework. All right, thanks, Michelle.

• 35:44Speaker 00

  Thanks, Meryl.

• 35:49Speaker 00

  That's Science Versus. There were 58 citations in this episode. If you'd like to check them out, just head over to our show notes and click on the link to our transcript.

• 36:06Speaker 00

  This episode was produced by me, Michelle Deng, with help from Rhodes Brimler, Merrill Horn, Aketi Foster-Kees, and Wendy Zukerman. We're edited by Blythe Terrell. Our executive producer is Wendy Zukerman. Mix and sound design by Bobby Lord. Fact checking by Erica Akiko Howard. Music written by Peter Leonard, Bobby Lord, So Wiley, Emma Munger, and Boomi Hadaka. And a special thanks to researcher Dr. Isis Sapunanate, who also spoke to me for this episode. We'll fact you soon.

• 36:44Speaker 17

  This episode is brought to you by State Farm. Football has a play for just about everything. You can go deep, keep it on the ground, or draw up something nobody sees coming. And whether you want to run a flea flicker or the tush push, you need a plan to fit your unique situation. That's why State Farm takes the time to get to know you so they can help personalize coverage for your life and budget. Now that's a solid game plan. Like a good neighbor, State Farm is there.

• 37:13Speaker 18

  When fall comes back around, there's a sense of a reset. And new pieces from Lululemon's Fall Drop are an inspiration to push your goals and elevate your routines. As your calendar fills, easy-to-layer styles meet the demands of your day. And as you challenge yourself to try even more, versatile sets transition with you. The Lululemon Fall Lineup brings new levels of comfort and confidence, whether you're starting something fresh or starting something over. Check out the latest arrivals in-store and on lululemon.com now.