Why Daylight Saving Time is Bad for Your Health | Samer Hattar & Andrew Huberman
00:00:00.000 | If you're going to go out in the morning, in the summer, you're going to get much brighter.
00:00:06.760 | That's why I don't like the change in time.
00:00:08.280 | I know people think, "Oh, because you're biased, you..."
00:00:11.880 | Because I think...
00:00:12.880 | Wait, wait, wait.
00:00:13.880 | Sorry.
00:00:14.880 | The change in time, you're talking about daylight savings?
00:00:15.880 | Daylight saving.
00:00:16.880 | It's such a bad idea because it disrupts that rhythm that you're having.
00:00:21.400 | Because I think your body, if you keep that rhythm, you will see the whole seasonality.
00:00:26.040 | And I look at it from a different aspect than other people.
00:00:29.400 | It really...
00:00:30.400 | And people say, "I'm biased because I'm a morning person."
00:00:32.440 | And it may be true.
00:00:34.360 | But there's a situation...
00:00:36.120 | Secret conspiracy about morning people.
00:00:38.280 | Yeah.
00:00:39.280 | But there is...
00:00:40.280 | If you think about it, Andrew, there is a situation where you're getting light perfectly
00:00:44.440 | well and then all of a sudden, they delay it by one hour because...
00:00:47.920 | And then, even though it's the summer, your body now, if you're still not adjusting, think,
00:00:53.120 | "Oh, wait.
00:00:54.120 | What happened?
00:00:55.120 | What kind of happened?"
00:00:56.120 | I love that you're bringing this up because I always thought, what's the big deal?
00:01:00.400 | One hour.
00:01:01.400 | Right?
00:01:02.400 | One hour shift.
00:01:03.400 | Spring forward, fall back.
00:01:04.400 | It's so hard to adjust to one hour.
00:01:05.880 | But this goes back to the beginning of our discussion.
00:01:08.960 | It's not just one hour.
00:01:10.520 | Right.
00:01:11.520 | Because it's one hour across that one day.
00:01:13.400 | But there's this cumulative effect on the clock and these three elements of your tripartite
00:01:19.240 | model.
00:01:20.240 | Right?
00:01:21.240 | The homeostatic sleep and the direct effects on mood.
00:01:23.160 | And when it's so close, it's sometimes hard to figure out how to adjust it perfectly.
00:01:28.560 | Because we're already sleep-deprived in our society and then you shift it.
00:01:33.940 | So it all accumulates and it has no benefit.
00:01:37.600 | Well, you work at a major government organization, National Institute of Mental Health.
00:01:41.440 | Why don't we campaign for- Honestly, I have no idea.
00:01:44.720 | I mean, it makes no sense.
00:01:45.720 | No, I'm saying, why don't we go campaign for- Yeah, I would love to.
00:01:48.200 | I mean, it makes no sense to have the summer light goes up at 9 p.m.
00:01:53.560 | The light goes down where I live in Baltimore at 9 p.m.
00:01:57.040 | And then all of a sudden, when you really want to see the light longer in the day, you
00:02:02.120 | now shift the other way.
00:02:03.760 | And now it goes all of a sudden at 6 p.m.
00:02:05.560 | Why do you do these drastic changes?
00:02:07.240 | Well, let it blend across the whole season.
00:02:10.840 | You know, yes, later, earlier at night, but it's at least consistent.
00:02:15.160 | It goes in a very consistent manner.
00:02:17.240 | I just don't understand why they do this.
00:02:19.280 | It makes no sense.
00:02:20.280 | Well, I think that the reason they do it is because they don't understand the biology.
00:02:25.660 | Because one hour seems trivial unless you understand the repercussions of that one hour
00:02:30.800 | shift.
00:02:31.840 | Because what's also clear now, based on what you're saying, is that that one hour shift
00:02:36.120 | is taking you out of alignment with the natural light-dark cycle in exactly the wrong direction.
00:02:42.080 | It's pushing people to get even later.
00:02:44.760 | In the summer, when light is going to push you later anyway, it doesn't make sense.
00:02:49.320 | You put it beautifully.
00:02:50.320 | I just rambled.
00:02:51.320 | No, no.
00:02:52.320 | You made it clear.
00:02:53.320 | I mean, it's like literally it made people who are having problems having an advanced
00:03:00.160 | sleep rhythm because they are delayed.
00:03:02.440 | Now you give them this hour to make them even more delayed.
00:03:05.320 | You push them even later in the day-night cycle.
00:03:08.080 | It just doesn't make sense at all.
00:03:11.520 | I think 2022 should be the year that we abolish daylight savings.
00:03:14.880 | Oh, man.
00:03:15.880 | That would be the day for me, honestly.
00:03:18.680 | Well, also if it has a positive effect on what is essentially an epidemic of mental
00:03:24.440 | health issues and other issues related to improper interactions with light, that, I
00:03:31.080 | think, is a well worthwhile cause and we can explore it.
00:03:36.100 | So for once, we're going to fight with another group, a common battle, as opposed to with
00:03:40.920 | one another.
00:03:41.920 | I mean, the circadian people, honestly, to give them credit, have been trying for years
00:03:45.320 | to abolish daylight savings.
00:03:46.880 | Yeah, the problem is they all go to sleep at 9 p.m. and wake up at 4 a.m. so we never
00:03:50.840 | see them.
00:03:51.840 | That's right.
00:03:52.840 | No, the circadian community has done an amazing job of figuring out what we need.
00:04:00.120 | And then the challenge, of course, is making sure that people get what they need and making
00:04:04.960 | sure that at a societal level, we're not vaulting ourselves into the wrong direction.
00:04:09.200 | The biggest problem is that the late waking people, they think that really, and I'm going
00:04:15.800 | to try to put it in a better way now, they think, "Oh, because you're a morning person,
00:04:19.840 | you want to see the sun early, so you want me to suffer it dropping late."
00:04:24.520 | But that's not the case because what happens is when they shift it back after the daylight
00:04:30.660 | saving, now they're going to make you suffer really badly because now it's going to be
00:04:35.480 | earlier.
00:04:36.480 | Right, in the fall.
00:04:37.480 | In the fall when there's not enough light, if they keep it the same way.
00:04:41.000 | So try to convince them that actually this at the end causes more trouble when you need
00:04:46.160 | the light for your late schedule in the fall when they shift it back.
00:04:51.680 | Then they say, "Keep it daylight saving all the time."
00:04:54.280 | And that has been proven.
00:04:56.440 | That is very bad.
00:04:57.920 | Like people have done studies that literally two areas close to each other and areas that
00:05:03.120 | were the whole year on daylight saving has much more problems.
00:05:07.920 | Even in cancer rates, in depression.
00:05:09.760 | So you don't want to do that.
00:05:11.280 | So that's what trying to convince people that you need to prevent that switch and you don't
00:05:17.840 | need daylight saving at all.
00:05:20.200 | That's where the problem happens.
00:05:22.040 | Interesting.
00:05:23.040 | I had not thought about that, but yes, you late risers in the fall when you fall back,
00:05:29.640 | as they say, spring forward, fall back, you dial back the clock.
00:05:32.540 | It's really compounding the problem that already exists.
00:05:35.920 | Exactly.
00:05:36.920 | And it's really nice if you keep it consistent.
00:05:39.560 | In the spring, you get the equinox and then the days start going up.
00:05:45.160 | And then even in the summer start going down, and then the fall, you get the other equinox
00:05:48.960 | and go back.
00:05:49.960 | So it's very symmetrical, right?
00:05:51.800 | It goes into short day, longer, long, long, long, then short day again.
00:05:56.640 | But now you're getting these bumps in both sides of the spring and fall.
00:06:01.320 | Why would you do that?
00:06:02.620 | Something that is beautifully symmetrical, beautifully smooth, you're putting bumps into
00:06:06.740 | it.
00:06:07.740 | Well, and we are not just beautiful because it's there, but it, but evolved.
00:06:11.260 | I mean, essentially this is the system we evolved in for hundreds of thousands of years.
00:06:16.180 | Even apart from the exact equator, every part of the earth have seasonality.
00:06:20.560 | Right.
00:06:21.560 | Yeah.
00:06:21.560 | Yeah.
00:06:26.560 | you
00:06:28.620 | you