DAVID FOLK THOMAS: Welcome to our webcast. I'm David Folk Thomas.
Whether you're traveling for business or pleasure, jet lag often keeps you from making the most of your trip. You've probably heard all sorts of tips on how to prevent jet lag, but what really works?
Here to talk to us about the biology of jet lag and what you can do to get your body back on schedule, we have two sleep experts. On my left, is Dr. Daniel Wagner. He's the medical director at the Sleep-Wake Disorder Center at the New York Presbyterian Hospital in Manhattan. And next to Dr. Wagner is Dr. Shelley Zak. She's an attending physician at the aforementioned Sleep-Wake Disorder Center at the New York Presbyterian Hospital. Doctors, thanks for joining us today.
Let me start with you, Dr. Wagner, and let's talk about jet lag. Lots of people fly out there-- is jet lag a real problem or is it psychological, and we're all just imagining something?
DANIEL WAGNER, MD: Oh, it's a very real problem. And it's due to the fact that we have an internal clock that tends to get set to the time zone we live in every morning and most people's clocks do a pretty good job of that. But, the clock was not designed to suddenly go across the country or across the ocean on a jet plane. It evolved over millions of years to basically, pretty much stay in the same place from day-to-day. And so it has a limited flexibility as to how it can time our internal functions in concert with the external world. It's the light-dark cycle of the external that does the retiming and synchronizes our internal clock to the outside world.
And so when you suddenly zip over to another time zone and there's a different light-dark cycle, your clock is still set to the home. And because of that it tries to make your body function, to sleep and wake at the times like home. But you're not at that time any more. And it takes about an hour per time zone for your clock to catch up to the new time zone.
Because of that, people very often have trouble sleeping at the new time. Particularly, trouble waking up a lot in the second half of the night. And then they're tired and sleepy in the daytime -- both because of that insomnia, but also because their body clock is still on, let's say, New York time when they're in Hawaii. And when you're supposed to falling asleep -- New York time, let's say it's 11 o'clock -- it's only about 5 o'clock in the afternoon in Hawaii.
DAVID FOLK THOMAS: But at least you're in Hawaii. Dr. Zak, can you elaborate more on the light-dark thing that Dr. Wagner was just mentioning?
SHELLEY ZAK, MD: Oh, absolutely. As Dr. Wagner mentioned, we have a biological clock. And our biological clock is actually set to a little bit more than twenty hours. So how is it that we tend to function in a twenty-four hour world? Well, the time and amount at which you see light in the morning, helps set the biological clock. And this is extremely important, because it's one of the treatments for jet lag. And the whole problem is it's light outside, but you're biological clock says you should be sleeping.
And what we look at when treating jet lag is, again, ways to affect the biological clock. And there are two things that can affect it. Number one is the timing of light, when you first see light. And the other is melatonin. And they work at opposite ends of the spectrum. So having light in the morning does the same for you as melatonin in the evening. So you actually sort of dose them across the day from each other.
DAVID FOLK THOMAS: Melatonin, to elaborate on what melatonin is? Just very briefly.
SHELLEY ZAK, MD: Melatonin is a hormone. And we know a lot about it, but there's also a lot we don't know. I think perhaps the best description is that it's the hormone of darkness. And it is debated throughout the sleep community: does melatonin actually help you sleep? Because everyone and his brother knows that you can go to your local pharmacy and get melatonin to help you sleep. Or is it working by shifting your biological clock? And you have experts on both sides of the argument, slugging it out.
DANIEL WAGNER, MD: Though this expert thinks it's the latter.
SHELLEY ZAK, MD: Yeah, I know. I.e., that it works by changing one's biological clock and not by directly putting you to sleep the way a sleeping pill might do.
And so in general the hard part -- at least from my experience and from what most people would say -- is probably traveling eastward as opposed to westward. I do fine going to Hawaii. And part of that is that our biological clocks really are somewhat longer than twenty-four hours. Exactly how long they are isn't really clear, but you probably realize, it's a lot easier to stay up later than it is to go to bed earlier. And eastward travel is exactly the latter.
And so what we generally try to help our patients do is to be able to fall asleep earlier. And the way to do that is a combination of melatonin and morning light. The general recommendation, when one's flying eastward, is to take melatonin at the equivalent of 10 PM where you're going. So let's say you're going to Europe, which is six hours later than New York. So you would want to take it at 4 PM New York time. Which is equivalent to 10 PM European time the day you're traveling. And the attempt is to try to pull your biological clock earlier.
Then when you get there, the next morning -- you want to get yourself up and out -- you want morning light exposure. You want to get that light on your retina. To help switch your biological clock. And you would probably need another dose of melatonin that night, now at 10 PM what is local time, European time. And again, get up in the morning.
And we usually say go for a half-hour walk. You don't want to wear sunglasses, because the whole point is that the biological clock is reset by light falling on the retina.
On the other hand, don't stare at the sun. It will destroy your retina.
So just, go for a walk. Ambient light is fine. Even on a cloudy day, you're getting more than enough light.
And that's the general recommendation. Along with trying to sleep on the plane. Again you're trying to get yourself on an early,or later, schedule.
DANIEL WAGNER, MD: Depending on which way you went. Another recommendation that is made -- based on the data from some studies that were done at New York Presbyterian in the Institute of Chrono-Biology Lab -- is to not nap at your new destination. Because what you're tending to do is sort of keep your clock set to your home time zone. By sleeping at that time. Instead, you should stay up the entire day. And then go to bed at your new time in the new time zone. So rather than try and sort of catch up -- even if you didn't sleep very well on the plane -- you'll tend to delay you're adjustment if you nap in the daytime. So, that is usually, should be avoided. As you get to your new destination.
DAVID FOLK THOMAS: Now if you're a on a very brief business trip -- maybe, you're going to Europe for one or two days -- you just want to tough it out or by the time you get that clock set, you're going to be back home?
SHELLEY ZAK, MD: You adjust, you're going to, right. You know, that is probably where the newer sleeping pills are very helpful. Because you're right. You know, as soon as you get yourself on, you're going to have to get back off.
There are some newer, short-acting sedatives that probably would be very helpful in that setting. Because, you're right. You need to get to the hotel and get to sleep and do your presentation the next morning and then you're going to catch a flight right back. And that's where zolpidem and zaleplon, which are the newer, very short-acting sleeping pills probably have their primary role.
DAVID FOLK THOMAS: All right, that's all the time we have, it's time to go to bed right now. I'm David Folk Thomas and we'll see you next time.
Whether you're traveling for business or pleasure, jet lag often keeps you from making the most of your trip. You've probably heard all sorts of tips on how to prevent jet lag, but what really works?
Here to talk to us about the biology of jet lag and what you can do to get your body back on schedule, we have two sleep experts. On my left, is Dr. Daniel Wagner. He's the medical director at the Sleep-Wake Disorder Center at the New York Presbyterian Hospital in Manhattan. And next to Dr. Wagner is Dr. Shelley Zak. She's an attending physician at the aforementioned Sleep-Wake Disorder Center at the New York Presbyterian Hospital. Doctors, thanks for joining us today.
Let me start with you, Dr. Wagner, and let's talk about jet lag. Lots of people fly out there-- is jet lag a real problem or is it psychological, and we're all just imagining something?
DANIEL WAGNER, MD: Oh, it's a very real problem. And it's due to the fact that we have an internal clock that tends to get set to the time zone we live in every morning and most people's clocks do a pretty good job of that. But, the clock was not designed to suddenly go across the country or across the ocean on a jet plane. It evolved over millions of years to basically, pretty much stay in the same place from day-to-day. And so it has a limited flexibility as to how it can time our internal functions in concert with the external world. It's the light-dark cycle of the external that does the retiming and synchronizes our internal clock to the outside world.
And so when you suddenly zip over to another time zone and there's a different light-dark cycle, your clock is still set to the home. And because of that it tries to make your body function, to sleep and wake at the times like home. But you're not at that time any more. And it takes about an hour per time zone for your clock to catch up to the new time zone.
Because of that, people very often have trouble sleeping at the new time. Particularly, trouble waking up a lot in the second half of the night. And then they're tired and sleepy in the daytime -- both because of that insomnia, but also because their body clock is still on, let's say, New York time when they're in Hawaii. And when you're supposed to falling asleep -- New York time, let's say it's 11 o'clock -- it's only about 5 o'clock in the afternoon in Hawaii.
DAVID FOLK THOMAS: But at least you're in Hawaii. Dr. Zak, can you elaborate more on the light-dark thing that Dr. Wagner was just mentioning?
SHELLEY ZAK, MD: Oh, absolutely. As Dr. Wagner mentioned, we have a biological clock. And our biological clock is actually set to a little bit more than twenty hours. So how is it that we tend to function in a twenty-four hour world? Well, the time and amount at which you see light in the morning, helps set the biological clock. And this is extremely important, because it's one of the treatments for jet lag. And the whole problem is it's light outside, but you're biological clock says you should be sleeping.
And what we look at when treating jet lag is, again, ways to affect the biological clock. And there are two things that can affect it. Number one is the timing of light, when you first see light. And the other is melatonin. And they work at opposite ends of the spectrum. So having light in the morning does the same for you as melatonin in the evening. So you actually sort of dose them across the day from each other.
DAVID FOLK THOMAS: Melatonin, to elaborate on what melatonin is? Just very briefly.
SHELLEY ZAK, MD: Melatonin is a hormone. And we know a lot about it, but there's also a lot we don't know. I think perhaps the best description is that it's the hormone of darkness. And it is debated throughout the sleep community: does melatonin actually help you sleep? Because everyone and his brother knows that you can go to your local pharmacy and get melatonin to help you sleep. Or is it working by shifting your biological clock? And you have experts on both sides of the argument, slugging it out.
DANIEL WAGNER, MD: Though this expert thinks it's the latter.
SHELLEY ZAK, MD: Yeah, I know. I.e., that it works by changing one's biological clock and not by directly putting you to sleep the way a sleeping pill might do.
And so in general the hard part -- at least from my experience and from what most people would say -- is probably traveling eastward as opposed to westward. I do fine going to Hawaii. And part of that is that our biological clocks really are somewhat longer than twenty-four hours. Exactly how long they are isn't really clear, but you probably realize, it's a lot easier to stay up later than it is to go to bed earlier. And eastward travel is exactly the latter.
And so what we generally try to help our patients do is to be able to fall asleep earlier. And the way to do that is a combination of melatonin and morning light. The general recommendation, when one's flying eastward, is to take melatonin at the equivalent of 10 PM where you're going. So let's say you're going to Europe, which is six hours later than New York. So you would want to take it at 4 PM New York time. Which is equivalent to 10 PM European time the day you're traveling. And the attempt is to try to pull your biological clock earlier.
Then when you get there, the next morning -- you want to get yourself up and out -- you want morning light exposure. You want to get that light on your retina. To help switch your biological clock. And you would probably need another dose of melatonin that night, now at 10 PM what is local time, European time. And again, get up in the morning.
And we usually say go for a half-hour walk. You don't want to wear sunglasses, because the whole point is that the biological clock is reset by light falling on the retina.
On the other hand, don't stare at the sun. It will destroy your retina.
So just, go for a walk. Ambient light is fine. Even on a cloudy day, you're getting more than enough light.
And that's the general recommendation. Along with trying to sleep on the plane. Again you're trying to get yourself on an early,or later, schedule.
DANIEL WAGNER, MD: Depending on which way you went. Another recommendation that is made -- based on the data from some studies that were done at New York Presbyterian in the Institute of Chrono-Biology Lab -- is to not nap at your new destination. Because what you're tending to do is sort of keep your clock set to your home time zone. By sleeping at that time. Instead, you should stay up the entire day. And then go to bed at your new time in the new time zone. So rather than try and sort of catch up -- even if you didn't sleep very well on the plane -- you'll tend to delay you're adjustment if you nap in the daytime. So, that is usually, should be avoided. As you get to your new destination.
DAVID FOLK THOMAS: Now if you're a on a very brief business trip -- maybe, you're going to Europe for one or two days -- you just want to tough it out or by the time you get that clock set, you're going to be back home?
SHELLEY ZAK, MD: You adjust, you're going to, right. You know, that is probably where the newer sleeping pills are very helpful. Because you're right. You know, as soon as you get yourself on, you're going to have to get back off.
There are some newer, short-acting sedatives that probably would be very helpful in that setting. Because, you're right. You need to get to the hotel and get to sleep and do your presentation the next morning and then you're going to catch a flight right back. And that's where zolpidem and zaleplon, which are the newer, very short-acting sleeping pills probably have their primary role.
DAVID FOLK THOMAS: All right, that's all the time we have, it's time to go to bed right now. I'm David Folk Thomas and we'll see you next time.