Short Wave - Don't Let Jet Lag Ruin Your Holiday Plans

Episode Date: November 18, 2024

Getting enough sleep regularly can be tough — and even harder when you're traveling for the holidays. "We need sleep like we need water," says Jade Wu, a behavioral sleep medicine psychologist and author of the book Hello Sleep. She and host Regina G. Barber discuss what's happening to our bodies when we get jet lag and the clocks in our body get out of whack. They also get into the science of the circadian rhythm and how to prepare for a long flight across time zones. Check out CDC's website for tips on minimizing jet lag.Want to hear more science of holiday living? Email us your ideas to [e-mail] — we'd love to hear from you! Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave. See pcm.adswizz.com for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences.NPR Privacy Policy

You're listening to Shortwave from NPR. Hey, short wavers, the holidays are approaching, and that often means lots of travel. Across the country or internationally, which often just, like, knocks me out. But that exhaustion can happen even if you're not traveling. I stayed in exactly my house, but I had a baby, which means that my schedule got topsy-turvy, turned all the way around, and it felt like I had jet lag even though I didn't go anywhere. That's Jade Wu, a behavioral sleep medicine psychologist and the author of the book, Hello Sleep.

And I called her up because I, and I suspect many of you shortwavers, are about to put our bodies through that exhaustion again. In a few weeks, my partner and I are going to Australia, New Zealand, which has basically the opposite day and night cycle from here in D.C. So we're going to be extremely jet-legged. Jet-leg is when your body very visage. very quickly changes time zones so that your internal body clock becomes mismatched with the outside environment. Our bodies have billions of clocks. They're in our cells, our organs, our brains,

and they make up our circadian rhythm. The circadian system should work like a symphony that plays in sync together and on time. If all our clocks run as they should, and together in sync, then our circadian rhythms are doing great. And so that's why when we get jet lagged or, you know, have a baby and your whole schedule goes tops you turvey, what happens is that your internal circadian rhythms, your internal clocks start to not play in sync with each other or start to shift. And they no longer match the day-night cycle that's actually in your environment. So that symphony is making very distressing music?

Yes, it sounds jarring. It doesn't make sense. You're like, this is just noise. It's not music. That noise can mess up our basic bodily functions. We might be really tired or have difficulty concentrating, can't remember stuff, can't react quickly. Also, just be physically run down, tired, exhausted, unmotivated, lethargic. And if you have other medical conditions already, like chronic pain or diabetes or high. blood pressure, all those things are going to be more exacerbated, or your symptoms are going to be worse when your circadian rhythm is misaligned from the outside world. So today on the show are circadian rhythm. How our bodies know when it's time to sleep and what happens when we don't? I'm Regina Barber and you're listening to Shortwave, the science podcast from NPR. So Jade, let's talk about like sarcadian rhythm a bit more, starting with like what's the natural sarcadian rhythm for humans.

So humans, most of us have 24.1 to 24.3 hour circadian rhythms. So that means that left to our own devices, if we didn't have any work, school, lights, schedules, any cues for when we should be doing what? If we just lived in perpetual twilight in a dark cave, then we will naturally feel sleepy, go to sleep and wake up later every day. Wow. That's for most of us. Some of us have 24.5 or even 25-hour rhythms. And those folks have, yeah, yeah. And these folks have a really hard time functioning in, you know, our 24-hour world because every day they're having to fight upstream, basically, to live in a 24-hour world when their body wants to live in a 25-hour world. And then occasionally someone's clock might be 23.8, for example. Yeah. They're getting sleepy at 7 p.m. They're waking up at 3, you know, ready to go. So it's not really helpful to be at either end of the spectrum of having too short of a circadian day or too long of a circadian day because our society runs on 24 hours. The Mars day is slightly over 24 hours. So, you know, those people with slightly longer ones, they can, you know, they can move to Mars. Great.

All right. So you talked about these like light cues and other cues, like, how? How does our body know when we should sleep? Great question. So light is by far the strongest cue that we can have. Because if you think about it, your brain lives in a dark cave, right? It's inside your skull. It doesn't know what's going on in the outside world.

Really the only way that it knows, whether it's daytime or nighttime, is by how much light is coming in to your eyes. So yeah, your eyes are not only the windows to your soul, but also the windows to your circadian rhythm. So ideally you have lots of light coming in into your eyes during the daytime. And that tells the brain, oh, hey, it's daytime. Let's, you know, send out signals to the rest of the body to get your metabolism running, get your body temperature up and, you know, get everything up and running.

And then if there's not a lot of light coming into the eyes, then that's where the brain says, oh, okay, it's nighttime. So it's time to send out some melatonin, which is the messenger that will tell the rest of the body to close down the factory to shut down the machines and to start resting for the night. So you're saying that light will affect how much melatonin is being produced in your body? Yes. So melatonin is a hormone that our bodies naturally produce. And it's really a timekeeping hormone. Sometimes people have called it the vampire hormone, the nighttime hormone, because it comes out at night. It ramps up, it starts to ramp up in the

evenings as it starts to get dark, stays high through the night and then goes away in the early morning hours. And it's basically sending the message to the rest of the body. Hey, it's nighttime. It's time to shut down. Or, hey, I'm going away now that time. That means it's about to be morning. So start to ramp up those systems. And so some people take like melatonin supplements to like help them go to sleep or help them get tired. What are your thoughts on those supplements? I would say melatonin is the most misunderstood supplement in all the world. And that's because people tend to think that melatonin that you can buy over the counter is a sleep aid. And it's not. It's really just synthetic melatonin that tries to mimic what your body naturally produces.

But the way that we often take it is not really helpful. So often people are taking it at bedtime or close to bedtime to bedtime to help them sleep, so to speak. But by that time, your own melatonin is already high. So taking melatonin is either going to be just a drop in the bucket and not make a difference. Or if you take too high of a dose of melatonin, then it stays in your system and lingers into the morning when your melatonin should be going away. So it's still going to be sluggish, lethargic. You know, it's not really going to get the machines running. And if you had to guess, what is the dosage of melatonin that people,

people ought to be taking, what would you say? Oh, I have no idea. Well, when we do use melatonin to help people with jet lag, with shift work, to try to shift the timing of their own natural melatonin release, we usually do it with a 0.3 to 0.5 milligrams, several hours before bedtime. So that's 10 times less than what's usually sold in the bottles. Three to five milligrams is usually what you see being sold on the shelves. And there's been a couple of really big studies showing that, you know, just off the shelf melatonin is wildly inconsistent in their dosage. So it might be up to five or even higher number of times as much melatonin as what's advertised on the bottle. And it's not regulated so you don't know what you're taking. Correct. It's considered a dietary supplement. It's not

regulated the same way that a prescription medication would be. So you don't know if you're getting any melatonin or too much melatonin. You might be getting serotonin or CBD or other stuff that is not, you know, labeled. Wow. Okay. So we've been talking about sleep, you know, beyond jet like, what are the consequences for like not paying attention to your body when you need that sleep? Because our bodies need sleep. Absolutely. Yes. We need sleep like we need water and food. It's just just foundational to our ability to exist and function. If we try to ignore our lack of sleep or even the timing of our sleep, if it's wildly inconsistent, or if it's just really misaligned with what our bodies naturally want to do,

then we end up not only not functioning at our best, but we also end up putting ourselves on a back leg in terms of our health in the long run. So we can have higher blood pressure, for example, and have more risk that's added or more risk that's accumulating towards heart disease. So, for example, we know that people who don't sleep enough and people whose sleep timing is very inconsistent. If we look at them 10 years later, 15 years later, they're more likely to have heart disease, more likely to have cancer, more likely to have had some sort of fatal health events. or just to have passed away. So these cumulative types of health risks can add up really over the years. And even things about our day-to-day quality of life.

Like if you have an injury or if you have chronic pain, not getting good sleep and not being on a good schedule, will exacerbate that pain and exacerbate our emotion dysregulation too. So we have a harder time coping with pain, coping with stress, coping with, you know, things that happen that are out of our control. So, yeah, emotionally, physically, mentally, we're going to be affected. Okay, so given all that, I'd love to end on empowerment. How can people listening prepare, like, and lessen their jet leg?

What you can do is start to shift your circadian rhythm towards your destination circadian rhythm. So for example, since you'll be traveling east, you can go to bed and get up a little bit earlier every day. Okay. Or if you have the freedom to do so, you could also go the other direction. You can go to bed later until you go halfway around the clock and you land on Australia time. Right. If you don't have the luxury of being able to shift your rhythm leading up to a trip, then the best thing you can do is, is just to try to protect your sleep as much as possible leading up to the trip, maybe even sleep a little bit more than you usually do. Don't force yourself.

If sleep doesn't come, it doesn't come. But give yourself the best opportunity to bank some sleep. And then when you do get to your destination, use your best friends light and naps to adjust to your new environment. So use light whenever you need to be a little. awake, especially in the morning of whatever day you need to be awake. So that means going outside. That means using a light box and use naps to catch up on the sleep that you lost through the process of shifting your rhythm. But don't nap too close to the time when you should be going to bed at your new nighttime. And then after a few days, hopefully you will have shifted over to your new schedule.

Jade, thank you so much for talking to us today. Oh, it's my pleasure. This episode was produced by Rachel Carlson. It was edited bar showrunner Rebecca Ramirez and Tyler Jones checked the facts. Jimmy Keely was the audio engineer. Betzanovin is our senior director and Colin Campbell is our senior vice president of podcasting strategy. I'm Regina Barber. Thank you as all. Always, for listening to Shortwave from NPR.