MS. REBECCA SHEIRFrom WAMU 88.5 at American University in Washington, welcome to "The Kojo Nnamdi Show," connecting your neighborhood with the world. I'm Rebecca Sheir, sitting in for Kojo. Coming up this hour, if you're doing it right, you should spend about a third of your life asleep. But for many people, finding eight hours of unconsciousness every day is nearly impossible. Work starts early, children wake up crying at two 'o clock in the morning, and sometimes we stay up late just to devour another episode of our favorite TV series.

MS. REBECCA SHEIRAnd hey, if lying in bed is too boring, our smartphone's instant entertainment is always nearby. In a way, it makes sense. When we're awake, we can have fun. We can make money. When we're asleep, not so much. So sometimes getting shut eye doesn't really feel like something we have to do right away. But the science is becoming more and more clear. Getting sufficient sleep plays a vital role in our health, in our happiness. It affects our memories, our diet, even our chances of living a long life.

MS. REBECCA SHEIRJoining me now to discuss the science of slumber is Dr. Michael Twery, Director of the National Center on Sleep Disorders Research at the National Institutes of Health. Welcome Michael.

DR. MICHAEL TWERYGood afternoon, Rebecca.

SHEIRAnd Dr. Danny Lewin, Associate Director of Sleep Medicine at the Children's National Health System. Thanks for joining us.

DR. DANNY LEWINGood afternoon.

SHEIRSo, doctors recommend we get seven to eight hours of sleep each night. But Michael, when you think about it, going back to the very, very early days. Being unconscious for a third of every day, while living in the wild, isn't that kind of dangerous?

TWERYWell, there's many hypotheses about how sleep might have been an advantage early on. You know, there's a lot of predators roaming about while we sleep. And while we sleep, we're motionless, and that's one idea about the importance of sleep early on. But science has really taken us a long, long way. We all know how sleep is important for our clarity of thought, for our interpersonal relationships, our emotions. And that is also important in staying awake, for safety.

TWERYAnd when we're driving around, being vigilant and perceptive of our surroundings when we're moving. But when we're still, it's perhaps not as important. What science has really added, I think, recently, is that last part that you mentioned. And that is how sleep is important to our health.

SHEIRWhat questions do you have about the science of sleep? How can you get the best quality each night? Join the conversation by giving us a call at 800-433-8850. Sending us a tweet. Our handle is @kojoshow or sending us an email at kojo@wamu.org. And Michael, doesn't sleep also play a role in helping with memory?

TWERYThat's absolutely true. So, part of the thing that happens during our memory is that there is a reshaping of the neural pathways that are important for memory. There's also a rebuilding of those cells, a regeneration of brain cells, a reorganization. So, one of the things scientists have learned is that our mind is always active. It's just that it's shifting function. Now, what the scientists have started to uncover most recently is kind of the nuts and bolts of that process.

TWERYAnd it turns out that the process that's involved in sleep regulation, the circadian clock is also controlling the energy in our cells. It's controlling the mitochondria. It's the powerhouses. And so, when cells don't have enough energy, they start to run inefficiently. And this is the newest -- this is the cutting edge of sleep science and research, helping us understand how not getting enough sleep, or sleeping irregularly, may lead to the erosion of our health, not only in our minds, but also in tissues throughout the body.

TWERYOur liver, our heart, our fat cells. And the insulin secreting cells and many others.

SHEIRSo there are many consequences to not getting the recommended seven to eight hours of sleep.

TWERYNot only not getting enough sleep, but also sleeping on a regular schedule. So, our body's chemistry is set up and organized around approximately a 24-hour clock. And this program is programmed into our genes. About 10 to 20 percent of the genes in every tissue of the body, every nucleated cell. Our immune system. Again, our heart, our lungs. All these cells are expressing this genetic programming in our brain, as well. And it's driving a host of processes. There are certain times of the day when our body's best prepared to eat certain types of foods.

TWERYFor instance, fats. And then there's other times of day when it's more engaged in restoration of those cells. And so, if we attempt to eat, say, a big slice of pizza or a big slice of chocolate cake at two in the morning, when our chemistry is attempting to repair our body, it handles that food inefficiently. It produces more fats, as one example of one of the ways things go wrong.

SHEIRYou mentioned sleeping at irregular intervals. I've heard the term micro sleeping. What is that?

TWERYYeah, so, you know, there's several processes that surround sleep. As we have a process that's driving us to stay awake and a process that's driving us to become sleepy. And as the pressure to sleep increases, it's possible that we start to micro sleep. And this is where, basically, we lose consciousness or portions of seconds or, at the most, a couple of seconds perhaps would just stay in the micro sleep range. And the reason -- you know, it's not a big problem if you're sitting at your desk not moving, except that you kind of are not working while you're sleeping.

TWERYBut the real problem with micro sleeps becomes one, we're not aware of it. You're unconscious when it's happening. And, but, then, if you're driving, or if you're operating dangerous machinery, the micro sleep can be a very serious threat. Because, as you know, your vehicle is moving very quickly, and within one or two seconds, you could leave the road, you could strike another vehicle and cause an accident. And again, the danger here is that micro sleeps are something that happens spontaneously.

TWERYIf you've ever -- those of your listeners who have perhaps been on the commute in the evening, perhaps in the wintertime after the sun has gone down, might remember that gosh, that commute was awful short. Is it possible that they were micro sleeping on part of that trip? That they were actually sleeping during portions, and that's why it feels short. Scientists have found, you know, observed this phenomenon and how big of a problem it really is. It's hard to measure.

SHEIRNow Danny, you work with younger patients. So, how does this play a role with kids and sleep?

LEWINWell, we know pretty reliably that sleep time in children has been significantly reduced. And that's due to a whole host of different factors. In adolescents, teenagers, schools -- early school start times contribute to sleep loss and sleeping at inadequate or inopportune times during the day. Younger children's sleep may also be reduced. The studies aren't quite as extensive as they are in older kids, but we're also concerned about the amount of time that younger children sleep.

LEWINAnd it's the range of activities available to them. Electronic media, pressure on them on a daily basis. If I might make one more comment, just on this issue of micro sleeps, we can reliably measure those in a sleep laboratory where we are sleep depriving subjects. Some of the cutting edge science actually shows that there are not only micro sleeps, but part of the brain goes offline during the day. Micro parts of the brain literally shut down. This does come from the animal literature, at this point. And not yet the human literature.

LEWINBut these shutdowns can probably interfere in human beings with learning, attention, safe behavior, emotional regulation, et cetera. So they're localized -- there's localized sleep that occurs in the brain, we think, particularly when you're sleep deprived or not sleeping at the optimal time.

SHEIRWhat questions do you have about the science of sleep and how can you get the most out of your non-waking hours? Give us a call at 1-800-433-8850 or send us an email, kojo@wamu.org. Turning back to the children, Danny. What are some of the effects we see in kids who aren't getting enough sleep? What are the negative consequences?

LEWINSo, there are certainly effects on attention. So, we have a large number of children currently diagnosed with Attention Deficit Hyperactivity Disorder and treated for that disorder. Certainly, in some cases, those kids do not get adequate sleep. Now, that may contribute to their underlying psychiatric disorder, but it may also be a primary problem. So, attention, being able to stay in attention. Learning is also impacted. As Dr. Twery noted, the ability to maintain or establish memories is affected. That occurs in children, as well.

LEWINAnd novel problem solving is also impacted by inadequate sleep. When we need to attend to multiple demands of the classroom during the day. Kids are attending to, in some cases, what's going on at home, what their friends are thinking about them, what the teacher is saying. Any other worries that they might have. Coordination of all those concerns is very complex and it may be that inadequate sleep contributes to discoordination. So, attention, mood regulation and then we think there are a whole variety of health consequences as well.

TWERYSo, just to add to what Danny was saying, one of the things that researchers have been able to show is that when we don't get enough sleep, our memories are altered or colored. So, a good night's rest, we tend to remember events in a better light, and when we have -- when we're tired and when we experience those events, we tend to remember those events in a very negative light. And many of your listeners might have that, you know, their own experience there. And as Danny was saying, the interpersonal aspects are very difficult.

TWERYI mean, we all have experienced that. When we're tired, we don't have as much patience. And clearly, that's important for children as well as adults.

SHEIRLet's turn to the phones now. We have Lewis, who's calling from Washington, D.C. Lewis, go ahead, please.

LEWISHi. Two quick questions. One, if you could speak to the theory of it being important to go to bed and try to rise at the same times each day, even on the weekends, or even on your days off from work. And secondly, what do we know now about the amount of sleep that's needed? Is this static across generations? Is it static across age? Do you need as much sleep when you're 50 as you did, maybe when you were 25 or less?

LEWINWell, the -- to both great questions. So the timing of sleep is actually set by various brain and physiological systems. As Michael was saying, deep in our cells, we have this coding of our optimal time to sleep. So, that depends a bit on age, so in adulthood, after about 25 or 30 years of age, going to bed at 10 or 11 'o clock at night and waking up at seven to eight a.m. is probably a reasonable schedule. However, for a teenager, teenagers typically cannot fall asleep that early. They need to go to bed 11 'o clock or later.

LEWINAn elderly adult will have difficulty staying up late often. And that's due to, again, these internal body clocks, a primary one in the brain. In terms of sleep time, or duration need, there is some variability across the life span. But the quality and nature of sleep changes, the brain activity, when we measure it, electrophysiologically, changes as we age. But the amount of sleep time probably does not change that much from the time we're in our early to mid 20s. There is a, obviously, a well-known decrease in sleep need from birth up through the early 20s.

SHEIRAnd what of Lewis' question about keeping our waking and sleeping time constant, say on the weekday verses the weekend.

LEWINYeah. Really critically important, because again, we have these biological clocks that dictate when we should go to bed and when we should wake up. If we end up with a lot of variability in that, we're actually affecting a whole host of different mental systems and biological systems. Just think about what it's like when we shift our clocks backwards or forwards at different times during the year and how that affects us during the week.

SHEIRToday we are talking the science of sleep on "The Kojo Nnamdi Show." My guests are Dr. Michael Twery, director of the National Center on Sleep Disorders Research at the National Institutes of Health, and Dr. Danny Lewin, associate director of sleep medicine, Children's National Health System. Give us a call, 1-800-433-8850. Talk to us about your sleep. I'm Rebecca Sheir in for Kojo Nnamdi.

SHEIRWelcome back. I'm Rebecca Sheir sitting in on "The Kojo Nnamdi Show." I'm talking about the science of sleep with Dr. Michael Twery, director of the National Center on Sleep Disorders Research at the National Institutes of Health, and Dr. Danny Lewin, associate director of sleep medicine at Children's National Health System.

SHEIRHow many hours of sleep do you need to feel awake and alert all day and what are your biggest challenges getting the right amount? Give us a call at 1-800-433-8850, find us on Facebook, send us an email, kojo@wamu.org. Now, Danny and Michael, you've both mentioned the negative effects that can arise from not sleeping enough, obesity, stress, problems with memory, even cancer. These are things everybody wants to avoid, of course. So what do you recommend for people who want to make sure they do get enough sleep?

TWERYOkay. So Rebecca, you know, this is a source of a lot of confusion. We all perceive the need to be more -- when we're not awake we feel sleepy, okay. So that's great. You know, that's only one indication. That's -- feeling sleepy is something that we're all very familiar with. It's something, you know, that we hear sleep enough until -- are you sleepy is a signal. But here's the issue.

TWERYScience, in the last ten or fifteen years has uncovered all these -- the genes and the chemistry that makes -- that links sleep and timing of sleep, how it drives the chemistry of every cell in the body. I mentioned earlier how it's part of the -- it helps to make sure that the batteries in every cell of our body, the chemical batteries are working well.

TWERYAnd so the -- we don't -- the problem is we don't have any sensors that tell us when that chemistry isn't going well. So one way to think about it is perhaps the way a car engine works. The many parts of the car engine, the moving parts all need to work together with very precise timing. The gas needs to be ignited at the right time, the pistons more, the valves move. All of these things move in concert and proper synchrony.

TWERYAnd when they don't move in synchrony what happens of course is that the engine doesn't run well. You hear noises. The engine knocks or pings. The gasoline mileage is not as high as it might otherwise be if the car engine was well tuned. And something similar is thought to happen when we don't get enough sleep or that we're sleeping irregularly to serve the rest of the health of our body other than sleepiness.

TWERYSo, yes, sleepiness is important. We need to be awake so that we can perform in school or in the office and we can drive safely. And then the other part of this is that we need to sleep that seven to eight hours at a regular time each day so that it serves the chemistry of our body, the hormones and all the factors that must work well. Because when t hey don't work well, this is when we see mechanisms of disease start to emerge.

SHEIRWhat about exposure to light? I spent a couple years in Alaska and I have to say, winters were challenging at first because it was always dark. Summer was challenging for sleeping because it was always light. So what are some tips in terms of the temperature of the room, the lighting where you're sleeping, Danny?

LEWINSo our bodies and brains did evolve back on the savannah thousands of years ago when there were 12 hours of light and 12 hours of dark. And we have evolved and adapted to situations where there are variable amounts of light. But light is absolutely critical. And the first place light goes when it comes into the brain is it hits this region of the brain that regulates our 24-hour sleep-wake cycles. And it basically works to shut down the hormones that initiate the whole sleep process.

LEWINSo decreasing sleep prior to bedtime is absolutely key.

SHEIRDecreasing light prior.

LEWINI'm sorry, decreasing light prior to bedtime is absolutely critical usually within one to two hours of bedtime. People who are jetlagged or who have other problems with their sleep will need to attempt to, when light exposure occurs -- or shift workers need to attend to when the light exposure occurs. So shutting down light just prior to bedtime, and that includes blue light, the light that comes from our multiple screens that we use, hopefully not in bed or in the bedroom, but...

SHEIRThat's a no-no.

LEWINThat we would view as a no-no. But quite sleep environment, dim sleep environment that's not going to be interrupted by pings and other prompts from the environment. And regularity is also important. And some people -- most people sleep much better when there's a regular routine, they're sleeping in the same place and the same cues are in the environment for them.

SHEIRWe're going to turn to the phones now. We have Jane calling from Annapolis. Jane, go ahead, please.

JANEHi. So I'm 55 and I think I've had sleep problems maybe my entire life but never really identified them as problems because I could stay up late and get up early and still function. But I feel lately I'm not functioning. And so I started taking a little bit of a pill that will help me sleep. And it actually does help me sleep maybe about six or seven hours straight. But is it the same restorative sleep as if I were getting that sleep naturally that's induced by some sort of medication?

LEWINThere are many medications that initiate sleep. And they all have different effects on sleep and on the body and the brain. Some of them we think are pretty safe for longer term use but they do suppress certain kinds of sleep and perhaps other brain chemical activity. So we generally like to advocate that optimal sleep-wake habits are addressed first, changing behavior, changing your relationship with sleep, how you view sleep, that that would be a first step. And then consider medications on a limited basis, but a combination of cognitive behavioral interventions in combination with medication.

JANEAnd if I can ask just one follow-up question, so what happens when I fall asleep and I feel like I've been asleep for so long but I wake up maybe a half hour later and then I cannot go back to sleep. I feel like I've been asleep a long time but, I mean, the clock shows 20 minutes, 30 minutes. And then I'm literally up all night. What is that?

LEWINWell, it could be many factors. It could be a underlying sleep disorder. So people who snore will sometimes be awakened from their sleep and have difficulty maintaining sleep. But we also, when we fall asleep at night, we discharge this hunger that we've developed for sleep over the course of the whole day. And sometimes we might have a brief arousal within a short period of time after we fall asleep.

LEWINIt's absolutely normal to awaken throughout the sleep period. There are dozens and dozens of minor micro awakenings that we have. Many w don't remember. Many it's just a rollover, adjust the pillow, if that. Then we have maybe a dozen or more full awakenings from sleep, completely normal. And what happens is for people with insomnia, difficulty initiating and maintaining sleep, they begin to attend to those arousals and get frustrated by them and activated by them, wonder what's going on. And that kind of wakes them up and keeps them awake.

SHEIRJane, thank you for your call.

JANEThank you so much for taking my call.

SHEIRNow, Michael, the recommended amount of sleep is seven to eight hours, as we keep talking about. But some people, like I've heard, Margaret Thatcher, former UK Prime Minister, they're known for functioning on very little sleep, four hours, five hours . How much variation is there and how much sleep do people need?

TWERYYeah, so there's a lot of variation in the amount of sleep people need. Some of it is about who people are. There are some very high-performing individuals all through history that are renowned for not sleeping many hours or perhaps not even sleeping through the night. There's a form of sleep, segmented sleep where people may start out the night. They wake up at some time, they do some work and then perhaps they go back to sleep.

TWERYAnd this is a pattern that's reported throughout history. We can find these individuals. But again, what's changing or what science is adding, as we study the chemistry of sleep and what it adds to our health, it's not clear that those are variations and they do exist and where people feel that this is causing them to have daytime problems, excessive daytime sleepiness, they should discuss them with their doctors, these problems with their doctor.

TWERYBut they -- what research is doing is -- and this is, again, at the very cutting edge, we're starting to understand how that might contribute to help problems over a lifetime. Not getting enough sleep, like the car engine that's poorly timely, how it contributes to undermining our health. So for instance, one example would be researchers are looking at the processing of proteins in different cells of the body. And when proteins are not properly processed by the cell because there's not enough energy, and this can be caused by irregular sleep schedules, the proteins don't fold. They're not packaged correctly and they're not mailed within the cell to the appropriate destination.

TWERYYou know, another finding recently has been looking at the locus coeruleus neuron. So the locus coeruleus is a region of the brain that's involved in -- we know very well because it mediates stress responses. It's a source of adrenaline within the brain. And one of the things that we're just now starting to focus research on in the last couple of months is the discovery that with irregular sleep or insufficient sleep these neurons stop functioning properly. And basically with -- in animal models they're able to show that this is a very rapid loss.

TWERYAnd finally, another finding just in the last year, many of you may -- of your listeners probably heard about the sewage system of the brain. It goes by the technical name lymphatics. And this is cerebral spinal fluid moving through the brain to remove all the -- basically the toxic chemicals that accumulate. Well, only during sleep does the cerebral spinal fluid get redirected deeper into the brain tissue. And it's much more effective removing some of the chemistries that are basically, you know, shouldn't be accumulating. When they do accumulate, they're associated with neurological disease like Alzheimer's.

TWERYSo there's -- this is the cutting edge of science and discovery. And one of the things research will have to do is figure out, you know, how to measure these processes and how to use it in medicine to help guide us, give us better information about how insufficient sleep is affecting us.

SHEIRDanny.

LEWINSo I'll just add that individual variability is key. And there's some data from a lab at University of Pennsylvania showing that there are probably four different types of people, those who can tolerate inadequate sleep and those who absolutely cannot. Nothing wrong with that. Nothing wrong with those brains or bodies but recognizing the individual on the street, recognizing what they can and cannot tolerate is key.

SHEIRGo ahead, Michael.

TWERYYeah, if I could pump in on that. So this is really, really important because we get a lot of confusing messages that seemingly are contradictory. On the one hand we're sitting here saying that we need seven to eight hours of sleep, Rebecca. But at the same time, you know, I think that your audience needs to be looking at the information. What is it that they're basing that information on?

TWERYSo if someone says, well I only need to sleep four hours a night, is it that they're talking about their ability to stay awake and vigilant in moving about or are they talking about the health of their body's chemistry? Because science is beginning to suggest that the -- we can maintain function, we -- awake we can attend this interview with perhaps very -- a series of very long naps, maybe nine hours a day. And that's enough for wakefulness, to sustain wakefulness. But to maintain this rhythm of chemistry requires this pattern, this 24-hour pattern in which seven to eight hours of sleep is the typical routine in people.

SHEIRHow many hours of sleep to you need to feel awake and alert all day and what are your biggest challenges getting the right amount? Give us a call. We're at 800-433-8850. Our Twitter handle is @kojoshow. Find us on Facebook or email us kojo@wamu.org. And now let's go to Christopher on the phones. Christopher's in Crofton, Md. Go ahead, please.

CHRISTOPHERHey there. I was just wondering -- I've heard of like a sleep schedule and I read it a while ago so it might kind of be foggy, my memory. But it's basically this guy was sleeping every, like, few hours for, like -- I want to say, like, half an hour and I think at end of the day, like, his overall, like, sleep only added up to, like, three hours a day. I know you were just talking about, like, maintaining that rhythm for the chemistry in your brain but I was just wondering, like, the validity of, like, maintaining, like, a productive work schedule off it.

SHEIRWith an alternate sleep schedule. A good question, Michael.

TWERYYeah, so let me take a stab at this and then Danny can give you the clinical perspective. So from -- you know, again, researchers have shown that it's possible to take a nap and that that is restorative. It helps us remove some of that pressure to sleep. But it -- and there are some -- also Danny had referred to -- Dr. Lewin had referred to some genes that have been discovered. There's variation in genes that help -- seem to help people resist the pressure to sleep. So they don't lose function as quickly as others.

TWERYBut at this point in time, no science has discovered a gene or a pattern of sleep that replaces the daily rhythm associated with optimal health. And, you know, maybe, you know, research has yet to discover it. Maybe it exists but we're not quite there yet.

SHEIRDanny.

LEWINI would just agree that seven to eight hours at night at the optimal time for us biologically is absolutely critical for our health and optimal function. There are solo sailors and others who have to be up every hour or two. And that take a real toll on them biologically and physiologically in the long term.

SHEIRWe got this email from Steve who brings up something we touched on earlier. He writes, "It's vacation season and many listeners, like me, may be traveling now or soon. What does the science of sleep tell us about the best way to cope with jetlag, either avoiding it or adjusting to it once at our destination?" Michael, what do you recommend for people about jetlag?

TWERYWell, certainly for jetlag I think that the most common recommendation is where people are -- should get enough sleep from the get-go. They should sleep -- if they can sleep to their -- way to the destination, if they can avoid eating too many carbohydrates or, you know, the sweets and things that we love to do while we're traveling to, you know, remove some of our worries and anxieties, and if we could get into tune with our destination time zone as quickly as possible, these can help reduce those differences. Danny, do you want to add something on the clinical side?

LEWINYeah, there's -- going into a period of anticipated jetlag rested is absolutely critical. I agree fully with what Michael said. And there's really no way to avoid it except when you get back to your home schedule, get back on track, optimally give yourself a buffer zone. We've got hundreds of thousands, millions of kids going back to school in a week or two. And those kids need to be well rested this week. We know they're not going to get a lot of sleep during that first week of school.

LEWINBut they also need to get back on a regular schedule, which means that they're going to -- if they have to wake up for school between 6:00 and 7:00 in the morning, then going to bed at an appropriate hour and beginning to work on their morning wake time. Often it's hard to force yourself to fall asleep at night but set a morning wake-up time, keep it regular and keep it pretty close to your target bedtime.

SHEIRThis goes back to what we were saying earlier, right about now with the sun still staying up pretty late, school's coming back and kids are having daytime later. So that does pose a challenge for bedtime.

LEWINYep.

SHEIRSo what do you think? Should our high schools start later for teenagers? What changes should workplaces make for employees to get enough sleep? Let us know what questions you have about the science of sleep and how you can make the most out of your non-waking hours. Give us a call at 800-433-8850. Send us an email to kojo@wamu.org. Find us on Facebook. Again, I'm talking with Dr. Michael Twery, director of the National Center on Sleep Disorders Research at the National Institutes of Health, and Dr. Danny Lewin, associate director of sleep medicine, Children's National Health System. Join the conversation after the break. I'm Rebecca Sheir in for Kojo.

SHEIRWelcome back. I'm Rebecca Sheir sitting in for Kojo Nnamdi. I'm talking about the science of sleep with Dr. Danny Lewin, associate director of sleep medicine, Children's National Health System, and Dr. Michael Twery, director of the National Center on Sleep Disorders Research at the National Institutes of Health.

SHEIRJust before the break, we started talking about children. The school year is about to start again. It's important that they get, you know, a full night's sleep. And I'm wondering, we've talked about the role of schools and school start times. So, Danny, I know that advocates say school should start later because that's what kids naturally need. Can you address that?

LEWINYeah, so particularly in adolescence -- and we now are defining adolescence or the onset of puberty after about 9 or 10 years of age -- there's a shift in the biological clock where these kids need to go to bed later and wake up later. They just cannot fall asleep early. And when we require them to wake up for school start times that are -- two large school districts in this region start, one starts at 7:20, another starts at 7:35 -- we're asking these kids to get up at 5:00 or 5:30 in the morning, which for an adult would be like asking, you know, them to get up at 3:00 or 3:30 in the morning.

LEWINSo these kids are getting up at times that really is biologically implausible for them. So they not only have inadequate sleep, but they're not sleeping at the optimal time. And when we talk about the cells in the body and brain -- particularly developing cells in the body and brain -- these kids need to sleep in the morning hours. So delaying school start times, there's strong evidence from districts across the country that not only do kids sleep more, they don't take advantage of the shift, but they're also sleeping more at a time that's biologically necessary for them to sleep.

SHEIRWhat are your thoughts on changing policies based on circadian rhythms? Should schools be more sympathetic to tired students? Give us a call at 1-800-433-8850. Or send us an email at kojo@wamu.org. And now we have a caller from Chantilly, Va. Imam, go ahead, please. You're on the air.

IMAMThank you, everybody. Thanks for taking my call. We live in Fairfax and I think the school in Fairfax usually they start the high schools around, pick up times, bus time is around 6:15. And when we try to wake up the kids, usually we have to wake him about 5:00 and sometimes there's a lot of pushing and arguing, say, hey get up, it's time for school. And I want to ask the doctor is, do they ever, Patrick County, do they ever talk to the county about this issue? Because I do understand already what you said that it's hard to wake up the kids.

IMAMMy child usually, in the middle of 10:00 a.m., he say, dad, I'm tired. I cannot even operate. Even I'm not pay attention to teachers. Sometimes they have a little argument with the teacher. Because you know teenagers today is always hard to deal with the teachers sometimes. So we went to the county and we explained to them. And it seems to me there is nobody listening. It's too early to wake up at 5:00 for a teenager. I had time that, you know, I used to be a teenager. And I used to hate when my parents wake me up even 8:00 in the morning, let alone 5:00.

IMAMAnd another thing that I want to say to the doctor actually, the reason that -- I learned one thing in my life. The more that I cut my expenses and I have less debt, I sleep well. And I spend what I have. If I don't have things, I don't buy it. And I really believe that, as an American, we spend more than what we don't have. And the more you spend more money and debt, you worry about how to pay it back.

SHEIRWell, thank you...

IMAMAnd I'll listen to my answer.

SHEIRAll right. Thanks for your call, Imam. So, Danny, is there an evolutionary reason for teenagers to be on this different sleep schedule?

LEWINWell, there are hypotheses about that. That, you know, if you think about animals or human beings, say antelopes out on the savannah. And you don't want them all sleeping at the same time during the period of night time when there are a lot of predators out. So one evolutionary theory -- and it is a theory -- is that at the beginning of the night, the adolescents are up late.

LEWINThey're on the perimeter. So they see a movement in the dark, they see the flash of an eye of a predator. They startle, and the whole herd goes off. And over the course of the night, with different circadian phases among the different developmental stages of that herd, the older group might move out in the early morning hours. So at least that's a theory.

SHEIRInteresting.

LEWINYeah.

SHEIRWell, let's turn now from adolescents to grown-ups. We got this email from Irene who wants to know about shift work. She writes, "Some weeks I work nights. Sometimes I work nine to five. How can I get a consistent sleep schedule when work is always changing? Can a changing sleep schedule be just as good, as long as I get seven to eight hours? So Danny or Michael, how can people who work a variety of shifts get the best sleep possible? Michael, go ahead.

TWERYSo, you know, the starting point is, one, is to follow the best schedule they can. And given that their work schedule is shifting and they have to adapt to it, then the other thing is to protect your sleep environment. And so you want to try to have -- set aside, if it's possible, seven to eight hours of time where you will not be disturbed. And it's not possible for everyone. And while you're trying to sleep, you should definitely try to darken the room. And there are special blinds and curtains, black-out curtains, that are available to help you shut the light out. Because light is one of the things that helps drive the neural pathways that are keeping us awake.

TWERYAnd so shutting out light will help remove that drive. And if they -- if you feel that the shift-work schedule is dragging you down, that you can't perform your work safely. Certainly, you know, see your physician and discuss your symptoms. Because there may be other strategies and guidance. And Dr. Lewin, do you want to add to that?

LEWINYeah, so light is critical. Caffeine and when you use caffeine is critical. When you eat, when you exercise, those are all important factors that contribute to maintaining a regular sleep-wake schedule. The news is not great on shift work -- that shift work really takes a toll on the body, brain and multiple physical systems. So for those people who do shift work, really focusing on protecting your sleep both through the environment and sleeping at, as much as possible, regular times that really fit your optimal schedule, which is for our species at night.

SHEIRNow, Michael, you do a lot of work on sleep disorders, which affect millions of Americans. What are some of the most common sleep disorders you've seen?

TWERYSo one of the areas in my office that we work with most extensively is sleep apnea, because sleep apnea is very common. It can occur in people of all shapes and sizes, at all ages. It can affect children. It's very common in the elderly. And it -- one of the things science has brought to this is understanding of why people have difficulty breathing. So if your listeners can hearken back 20 or 30 years, if you're that old, and think about, you know, our image of a snoring cartoon character or a snoring character in a movie. We used to see that as being a sign of restful sleep...

SHEIRRight, right.

TWERY...like a stereotype. And today that's changing. We no longer think of it that way. Because for a loud, chronic snorer, what's happening is, is they're having trouble breathing. Now we don't know just how little you can get away with not breathing. But it is a concern. And the science is bearing that out. We're understanding that as the hormones associated with aging are lost, that contributes to the risk of sleep apnea. Obesity contributes to the risk of sleep apnea. And we're also learning that -- how not breathing, not sleeping, as we discussed earlier, is affecting our health.

TWERYMostly hypertension, when we don't get enough air, our body sends an alerting signal, like an adrenalin response. It tells our heart to work harder. It tells the blood vessels to contract. And in the case of sleep apnea, this happens -- can happen hundreds of times a night. And eventually, the body simply stops adapting. It just keeps the blood pressure high all the time. So treating sleep apnea may prove to be one strategy, one approach for helping to manage blood pressure.

TWERYHeart attack, we see the same story. Heart attacks and heart failure can occur because the signals or adrenalin is telling the heart to work harder perhaps than it needs to. We're wearing the heart out early. It's -- again, it kind of goes back to that, in conjunction with the timing of a gasoline engine, we talked about the circadian biology. And that can also lead to inefficiencies. So not sleeping, the stress hormones and these inefficiencies can lead to early failure of the heart.

TWERYAnd these are all reasons why we're now looking at the bigger picture of metabolism and not breathing and not sleeping. So sleep apnea is one that we're definitely looking at. Another area that's very common is insomnia. People have difficulty initiating or maintaining sleep. And this is a very big problem. It affects, you know, maybe 10, 20 percent of the population, based on CDC surveillance data. And it's something that -- it's kind of tragic, because it affects our interpersonal relationships. It affects our emotions. It affects our, you know, our life in the workplace.

TWERYBut it's something that, you know, if you're having problems with this, discuss the symptoms with your physician and work out a plan that's best for, you know managing those symptoms. Because there are many tools available today.

SHEIRDanny, you want to add to that?

LEWINI'll just add that in children these disorders also occur. Sleep apnea does occur in children for a variety of reasons, some the same some different from adults. And it needs to be treated. The bottom line is that snoring is not a healthy condition. If you snore, it's not good for your spouse, your bed partner. And it is an indication that you're working harder than you need to, to get air into your lungs at night.

SHEIRGo ahead, Michael.

TWERYYeah. So just to add, you know, one thing -- one condition, it's very hard in kids I think to know, you know, they -- this feeling, do they exhibit excessive daytime sleepiness because they're not getting enough sleep at night? Or is there another kind of problem? And this is where it takes working with your physician or your pediatrician to help sort out the different possibilities. Because there are some sleep disorders that are sleep apnea. But there's also hypersomnia and narcolepsy that can first appear in children.

TWERYSo if you see a change in your child's behavior, it'd be worth perhaps discussing those changes with your pediatrician or physician, clinician, to see if there is something that needs to be looked at more closely. Insufficient sleep in children, for whatever reason, is associated, again, and statistically, with a much greater frequency of depression and suicidal attempts.

SHEIRGoing back to sleep apnea, luckily, technologically we've come a long way. Now we have the CPAP machine, which a lot of people are using. But I want to talk about a different type of technology, personal technology. All of our gadgets that are offering ways to help us get to sleep, stay asleep, wake up at the right times. Danny, what are your thoughts on all of these, the apps, the bracelets?

LEWINWell, I think we're a little ways off from these devices actually measuring our sleep and telling us whether or not we are getting good sleep and quality sleep. I do want to credit all of these manufacturers and all of this interest with bringing people's focus to good sleep. Because we really do need to focus on good sleep. We have validated instruments that measure optimal sleep periods at night. The evidence currently is that these devices aren't quite there yet. We've seen, you know, these devices both help people identify problematic sleep patterns.

LEWINBut we've also seen them cause panic in patients, because the sense that they're not getting adequate sleep at night. So, you know, the idea of the devices is phenomenal. I'm sure that they will be well calibrated in the future. But they also need to be used in conjunction -- as Michael just pointed out -- signs of inadequate sleep really require the care of a physician. These things need to be brought to the attention of a physician before you kind of try to cure yourself and diagnose yourself with a device that currently, probably is not quite evolved enough to really diagnose a problem.

SHEIRMichael, what are your thoughts on sleep tech?

TWERYYeah. So, I think it's a very exciting development. I mean, huge change. You know, the earliest sleep tech was a pencil and paper, where we called it the sleep diary. And it's still used a lot today. And now there's devices that -- a whole array of devices. You know, you can go to a chain grocery store or, you know, a box store, and you can find these devices.

TWERYAnd I think that another slant on this is to -- everyone should be thinking, breaking this down into two types of device. One is the type of device that's designed to help you better understand your health. So there's a lot of devices that fit into that. They provide information. They're not saying -- and then there's another -- there's another category device, which is what we'd think of in terms of medical diagnostics. And these have been rigorously tested, as Dr. Lewin pointed out. And so that doctors can be confident in what the signal is that comes from these devices.

TWERYAnd I think that as long as people keep that in mind, there are devices to help you understand your health, personal information. And then there are devices that have been rigorously tested, developed and very robust, for the purpose of a medical -- establishing medical diagnoses.

SHEIRBut then there's a dark side of personal technology as well. I mean earlier we were saying some of the basic recommendations for getting a good night's sleep are being in a dark room, you know, keeping it a little bit cool, using the natural light to wake up. And some would say these things are only big issues because of modern technology. I mean, 200 years ago, being away from your cell phone in the dark -- I'm thinking it probably wasn't a problem. So let's talk a little bit more, before we go, about how we can avoid the technology trap to help us get better sleep.

LEWINHmm. Well the -- obviously, I could use the word addictive. So some of these devices and our interactions with them are very, very addictive. I could use a softer word called habitual. So our habit, our routine behavior associated with these devices will tend to get us activated, will make us think that we need to use them before we go to bed at night, checking the email one more time, checking the news, becoming a news junkie and really becoming obsessed with it versus putting these things down at night is really, really key. We need to recognize this behavior in our self.

LEWINWe all have this biological kind of burse of activation that occurs within half an hour or so of bedtime that is probably protective, evolution early. But that burst often will lead people to get back online, do a little more work, do a few more chores around the house. Of being disciplined about keeping all these devices out of the bedroom, or if they're in the bedroom, shut down on a mode where they're not going to disrupt our sleep or tempt us -- this is particularly key for adolescents and children. Get the devices out of the room.

SHEIRThank you. Michael, we have a few more seconds. One last thought on that?

TWERYSo technology is always going to be moving forward. And I think that the best tool for your listeners is to understand what that technology -- the relationship of that technology to their health so that they can best -- take the best actions for them as individuals.

SHEIRWell, Dr. Michael Twery, director, National Center on Sleep Disorders Research, National Institutes of Health, Danny Lewin, associate director of sleep medicine, Children's National Health System, thank you so much for joining me today.

LEWINThank you.

SHEIRI'm Rebecca Sheir sitting in on "The Kojo Nnamdi Show." Thanks for listening.

SHEIRComing up tomorrow on "The Kojo Nnamdi Show," digital solutions for managing your life. Tech Tuesday explores news apps, gadgets and services to help you cross items off your to-do list. Then at 1:00, soldier girls. The true story of three women from enlistment through deployment and back home again. "The Kojo Nnamdi Show," noon till 2:00 tomorrow on WAMU 88.5 and streaming at kojoshow.org.