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[BEEPS] KAREN BARTA: State forecast this afternoon, partly to mostly sunny, and isolated showers possible in the Southeast. Highs in the upper 60s to upper 70s. For the Twin Cities, partly cloudy, high around 75. It's partly sunny around the region in Rochester at 62. It's 64 in Duluth and 70 in the Twin Cities. That's news from Minnesota Public Radio. I'm Karen Barta.

GARY EICHTEN: Thank you, Karen. Six minutes now past 12 o'clock. Welcome back to Midday on Minnesota Public Radio. I'm Gary Eichten. Working Nights is made possible in part by the Minnesota Public Radio Documentary Fund, with major support from Phyllis [? Paylor ?] in memory of Walter [? Stremmel. ?]

So when was the last time you pulled an all-nighter, not the last time you worked past midnight but when you actually stayed up from sundown to sunrise? Chances are you felt pretty groggy the next few days, and for good reason. Turns out for most of us, working all night involves struggling against our own bodies.

Unlike most other animals, humans are biologically programmed to sleep when it's dark and wake when it's light. We also appear to be alone among the animals in wanting to outwit the impulse to sleep. Well, as Stephen Smith of Minnesota Public Radio reports in our new documentary on the subject, scientists are trying to make it easier for the growing number of people who are working nights.

STEPHEN SMITH: On the night shift, you follow two clocks.

[DRUMMING]

One is that clock up on the factory wall or in the dashboard of your delivery truck. That's the clock telling you to stay on the job, awake and alert, until your shift ends at sunrise. Then there's another clock about the size of a pinhead down at the base of your brain. It's the one commanding the rest of your body to go to sleep now. That internal clock is an amazingly brawny little timepiece.

MELISSA BANHAM: When you work all night long, and you don't get to bed till 7:00, 8:00 in the morning and the sun's just coming up, I think-- I found it for myself very difficult. Even though I am very much a night person, I'm a night person up till, like, 3:00 AM.

SPEAKER: Right around 5 o'clock in the morning, you really hit that bone zone. It's the natural time when you hit that real deep sleep, and so it's a fight.

TED BAKER: We are very much a species that's designed to work well during the daytime and to be asleep at night, pure and simple. We have very bad night vision. We don't do very well at night. All of our physiological systems are shutting down, and our brains are really at their lowest performance ebb.

MARK ROSEKIND: Between 3:00 and 5:00 in the morning is the highest number of errors, incidents, accidents. Just the number of fatal single-car accidents that occur, there's no question your biological clock is driving that. It's indisputable now. Sleep is not up there as a national health concern, but it should be. So we understand really what price we're paying for dealing with this.

STEPHEN SMITH: What price? The people who study shift work and fatigue like to point out that some of the most notorious industrial catastrophes in recent history, the Three Mile Island nuclear power accident and the one at Chernobyl, or the chemical power plant disaster at Bhopal, India, all were caused by sleepy workers struggling against their biological clocks. Harvard University sleep researcher Charles Czeisler.

CHARLES CZEISLER: The National Commission on Sleep Disorders estimated that the cost to society in terms of productivity and errors and accidents and so on is about $70 billion a year. The human cost, of course, is when you see people being killed in automobile accidents because drivers are nodding off and falling asleep at the wheel, having been awake all night.

STEPHEN SMITH: Some 5 to 10 million Americans work nights. In the history of work, it's a relatively new shift. Until the invention of electric lights a century ago, most people rose and set with the sun.

But in many modern jobs, the assumption is that to work nights, all you need to do is get tough and learn to live on less sleep. Most night workers report that their bodies never really adapt to this schedule. Only in recent years have employers and scientists looked closely at how working all night can affect people.

SPEAKER: Color different color. Color it red, these-- thing up there.

STEPHEN SMITH: It's Monday evening in a suburban Minneapolis household.

SPEAKER: Color his eyes blue.

STEPHEN SMITH: The three Banham kids are coloring pictures and teasing each other while Mom and Dad get the evening chores done. Melissa Banham is a police sergeant who works the day shift investigating sex crimes. She used to work nights.

MELISSA BANHAM: It was very hard to adjust to. I never felt good. I never felt healthy. I never felt well rested. You're kind of in zombie zone the majority of the time.

SPEAKER: Come on.

STEPHEN SMITH: Melissa's husband, Don, recently went back to the night shift. It came with his promotion to lieutenant. He works 8:00 PM to 6:99 AM, a shift that cops call the dog watch.

Don seems reasonably well adapted to this schedule. When he gets home each morning, he helps the kids get dressed. Then he steals up to the bedroom.

DON BANHAM: And so I try and make the room as dark as I possibly can. I shut off all the phones. And I basically lock myself up in the room and hibernate.

I get my best sleep during the week when she's at work and the kids are at daycare.

What's the matter, Rach?

STEPHEN SMITH: 2-year-old Rachel has the chickenpox. She was too sick for daycare, so when Don got home this morning, after a 10-hour shift, he had a testy toddler to handle.

DON BANHAM: We went in the bedroom. And I turned on the TV. We have a VCR on the TV in the bedroom there. And I went downstairs and got some of her favorite movies and brought them up.

And I tried to nap in between that. So I've gotten a couple hours throughout the day.

STEPHEN SMITH: And you're on the fourth of a fifth-day-- five-day stretch. So you're feeling pretty crispy today.

DON BANHAM: Oh, absolutely. [LAUGHS]

SPEAKER: (ON RADIO) Squad 241 able.

[MUSIC PLAYING]

SPEAKER: (ON RADIO) 241 able.

SPEAKER: (ON RADIO) On a theft of a boom box, 2318 Fillmore. Caller's downstairs. Suspect is a teenager who lives upstairs. Unknown if he's home now.

SPEAKER: (ON RADIO) 241, copy.

[STATIC]

[RADIO CHATTER]

[PHONE RINGING]

DON BANHAM: It's Banham here. What's on fire out there south?

STEPHEN SMITH: Don Banham spends most of the night in his cruiser. As shift commander, he's the top cop for the whole city of Minneapolis tonight. Don's the one they call if something really big happens.

SPEAKER: (ON RADIO) A bicycle theft just occurre. Number--

STEPHEN SMITH: And if nothing happens, Don basically drives around, one end of town to the other, listening to the radio, waiting.

[BEEP]

According to surveys, few night workers actually choose the graveyard shift. Those who do, like Don Banham, often enjoy the freedom and increased responsibility that comes from having fewer bosses around. When the night is full of action, time passes quickly, and Don doesn't have to struggle so hard to stay awake. But he never knows what the shift will bring.

DON BANHAM: Well, it's 4 o'clock, and it's still staying pretty quiet.

STEPHEN SMITH: So is this the dog hour of the dog watch, 4:00 in the morning?

DON BANHAM: Yeah, especially when it's quiet. You learn to cherish these moments if it's-- if you've had a really--

SPEAKER: This one, vehicle was taking off. [? Cullen ?] was going westbound on 46 here.

STEPHEN SMITH: A squad reports that a suspicious car it stopped suddenly took off. The chase is on.

[RADIO CHATTER]

Don Banham steers towards the scene. But before he can get there, the chase is over, and so is the only potential excitement for the whole shift. A study in one big American city found that 80% of cops working dog watch fell asleep on the job at least once a week.

DON BANHAM: I know guys that have told me that, that they said, I just can't get used to it. The times that they've had to work dog watch, they just hated it with a passion. And regardless of how much sleep they got during the day, regardless of what they did, they said they just can't stay awake at night.

I've had guys tell me that they have stopped at red lights while working and have fell asleep at the red light. They're just that tired.

SPEAKER: Same.

DON BANHAM: Hey, I'm on 38th and Park right now. Where'd you say that fight was at?

SPEAKER: (ON RADIO) 3716 Park.

DON BANHAM: Copy. I'll be stopping by there as well.

SPEAKER: We're planning on [INAUDIBLE] for a robbery of person that occurred at 3424 Park, a robbery at gunpoint. Suspect--

STEPHEN SMITH: In humans, the biological clock is a cluster of thousands of nerve cells that dwell near the base of the brain. From an evolutionary point of view, that's the oldest, most primitive neighborhood in a mammal's brain. The clock generates circadian rhythms, a Latin word that means "about a day," because the cycles are roughly 24 hours long. The circadian timekeeper makes you the most sleepy in the morning and the most alert in the evening.

[MUSIC PLAYING]

To demonstrate how it works, let's imagine that your body is an automobile. For the heck of it, let's make it some odd little French number with a temperamental engine. Every morning, a driver shows up to guide your body from sunup to sundown.

SPEAKER: [SPEAKING FRENCH]

STEPHEN SMITH: This driver is your circadian pacemaker. Because your body's been parked all night, the engine is cold and sluggish first thing in the morning.

[ENGINE STRUGGLES TO START]

It generally takes a while to wake up.

[ENGINE SPUTTERS THEN STARTS]

Now, let's say that every morning, a trailer is hitched to this automobile.

[METAL RATTLES]

SPEAKER: (FRENCH ACCENT) Hey, watch the paint job.

DALE EDGAR: The trailer represents the body's accumulated need for sleep as the day wears on.

STEPHEN SMITH: That's Dale Edgar, of Stanford University's Sleep Research Center.

DALE EDGAR: After a good night's rest, the trailer should be empty. As the day wears on, the trailer gets loaded with an increasing weight of sleepiness. That sleep load keeps building, threatening to slow your body down.

[ENGINE STARTS]

STEPHEN SMITH: The circadian driver tries to keep the body's speed steady in its journey from morning to night.

DALE EDGAR: By evening, the trailer is getting so heavy with accumulated fatigue that the circadian pacemaker must really hit the gas to keep you awake.

[ENGINE WHINES]

STEPHEN SMITH: As the trailer gets heavier, the pacemaker pours on more gas, in the form of brain signals that promote wakefulness. Your alertness lags a bit after lunch but then steadily rises through the late afternoon. And like a hot engine, your body's core temperature also rises.

Then, after about 10:00 PM or so, the driver lets up on the throttle. And the engine shuts down for the night.

[ENGINE SPUTTERS AND STOPS]

DALE EDGAR: All that sleep drags you down very quickly. That's the sudden feeling you can get in the late evening, that you're really worn out and ready to snooze.

STEPHEN SMITH: Scientists believe that during sleep, the body's fatigue is unloaded from the trailer. The car is refueled. And when the circadian driver is ready the next morning, the journey starts all over again.

DALE EDGAR: But it's important to note that it's not just the number of hours of sleep that matter but the quality of sleep. If you can sleep through the night with fewer brief awakenings, then you unload that sleep more thoroughly. If you get a bad night's sleep or not enough hours, then the trailer is only half empty when you get going the next day. That sleep burden, or what we call sleep debt, can accumulate day after day, making you more tired and less alert.

[DRUMMING]

STEPHEN SMITH: Now, remember that this car metaphor is a generalization. Different people have different circadian drivers within them. Some feel most alert in the morning, others at night. And no one knows exactly why.

SPEAKER: You ready, David?

SPEAKER: Yeah, go ahead.

SPEAKER: All right, Richard, we're going to begin sub cals now. With your head still, please open your eyes and look straight ahead. With your head still, please close your eyes.

STEPHEN SMITH: Researchers at Harvard Medical School are studying the body's circadian rhythms by sequestering human volunteers in windowless isolation rooms at Brigham and Women's Hospital in Boston. The scientists are studying ways to artificially shift a person's circadian rhythms.

SPEAKER: He closed his eyes here because the EEGs are more evenly spaced.

STEPHEN SMITH: It's just after noon. But for the 26-year-old fellow in room 4, it's bedtime. Lab technicians watch him on a TV screen while monitoring his brain and body functions by computer.

The subject is taking melatonin, the hormone that some people use as an over-the-counter sleep aid or to cure jet lag. While melatonin seems to work for some people, many doctors warn it's not gotten enough study to be considered safe for general use. At Harvard, researcher Charles Czeisler is seeing whether melatonin can be used to reset the circadian pacemaker.

CHARLES CZEISLER: The subjects in the melatonin study are actually on a 20-hour day, rather than a 24-hour day. So that means that every day for a month, they are going to sleep four hours earlier than they did the day before.

STEPHEN SMITH: You mean that poor guy has been in there for a month? I shouldn't say that. I'll back up. You mean that guy has been in there for a month?

CHARLES CZEISLER: [CHUCKLES] Well, by the end of this study, he will have been here a month. So each day, he's doing the equivalent of flying eastward across four time zones. And in this way, we're able to evaluate sleep taken at all different times of day, even though there's the same amount of wakefulness beforehand.

STEPHEN SMITH: In the 19th century, scientists recognized that plants and simple organisms set their daily rhythms by the sun. But humans, believing themselves too advanced for that, thought sleepiness a mere urge, to be conquered with willpower. In the last 20 years, Charles Czeisler and his Harvard colleagues proved that human circadian rhythms are also calibrated by sunlight. When light hits the eye, it sends a signal to the pacemaker, setting the internal clock. Czeisler and others believe that modern-day life under electric lights actually confounds the timing of our internal clocks, especially in the evening.

CHARLES CZEISLER: That allows us to stay up at a time that we normally would not physiologically have the desire to stay up.

STEPHEN SMITH: We'd want to be in bed by--

CHARLES CZEISLER: 10 o'clock or even earlier. So we have propelled our bedtimes to a later and later hour. And then we're still trying to get up at 6, 7, 8 o'clock in the morning in order to get to work.

STEPHEN SMITH: Czeisler adds that most of us are so accustomed to this sleep-deprived schedule we can't remember what it actually feels like to be well-rested and alert. The result, he says, is chronically lowered mental performance, reaction time, and memory.

JOHN PIONTKOWSKI: We have B waste test tank full on recirc. There's no intentions right now to starting up the circ system tonight just to dump that one tank. So we'll let that one go.

STEPHEN SMITH: For 30 years, the Connecticut Yankee atomic power plant split atoms so that lights and factories could glow throughout the night. In the main control room, shift supervisor John Piontkowski briefs his crew on what to expect in the coming eight hours, which isn't much.

JOHN PIONTKOWSKI: We are in no new tech specs. We have no new fire watches. We have no activity scheduled on the weekly activities sheet for tonight.

STEPHEN SMITH: The power company shut down this plant in 1996 after 30 years of service. The cold reactor looms on a bank of the Connecticut River about an hour south of Hartford. By law, a full operating crew must be on duty while the plant is slowly decommissioned.

JOHN PIONTKOWSKI: First off, we're just monitoring the spent fuel, all the fuel that's been taken out of the reactor. Plus, all the fuel that we had from previous cycles of running is in a pool, being cooled.

STEPHEN SMITH: To put it in blunt terms, you're staring at a pool of--

JOHN PIONTKOWSKI: Water.

STEPHEN SMITH: That's really boring.

JOHN PIONTKOWSKI: That's boring, real boring.

STEPHEN SMITH: Tedium makes staying awake all night even more difficult for these highly trained technicians. But they've also got a new ally in a set of specially designed overhead lights that can actually shift their circadian clocks. Based on technology patented by Harvard, the lights help push the body's natural 2:00 AM to 6:00 AM low point well into the later morning hours. That makes it easier to stay alert on the job and to sleep at home.

JOHN PIONTKOWSKI: Before the lighting, it was like, I'm on midnights. I'm in my cave. Leave me alone. When midnights are done, then we'll talk again.

SPEAKER: Between 3:00 and 6:00, you hit a-- what we call the bone zone. You have to get up, walk around, drink lots of coffee. And hopefully, at a nuclear power plant it stays boring, so it's hard to stay awake.

SPEAKER: Every time we're on midnights, you always have the same conversations. How do you sleep? Do you sleep when you first go home? Do you sleep when you-- and you're always talking about, oh, I slept lousy today.

And I couldn't get to-- I woke up every two hours. And everybody will have the same conversations. And once the lights came in, you just noticed that those conversations didn't happen.

SPEAKER: I love the lights. I've been here at CY for 22 years. And this is the first thing I ever found that helped me on midnights.

JOHN PIONTKOWSKI: I find I sleep a deeper sleep. I'm able to sleep a longer period of time. And if I'm interrupted with a phone call or anything during that sleep, I'm able to get right back to sleep.

STEPHEN SMITH: The trick to these lights is their intensity, 10 times brighter than average office illumination. They're still dim compared to an overcast day outside but bright enough to affect the circadian pacemaker. The lights are designed by Boston-based Shiftwork Systems. Company president Ted Baker says, knowing how to use light correctly, almost like a medicine, is the next stage in a revolution that started a century ago.

TED BAKER: When Edison lit up that first grid in Manhattan, the Edison Electric Company, he really opened a whole new world of-- which allowed continuous operation. And unfortunately, the light was not bright enough in most industrial settings, and still is not bright enough in most industrial settings, to even come close to having this necessary circadian shifting effect.

STEPHEN SMITH: Because nobody was thinking about the necessary circadian shifting effect.

TED BAKER: Well, nobody was thinking-- light was viewed as a means to see things only. We put in enough light to be able to read the page that's on our desk. Or we put in enough light to be able to see the gauges on the control panel. But we don't go much above that.

STEPHEN SMITH: Studies show that most night workers never get enough sleep during the day because the internal clock is screaming at them to wake up. The average nigh shift worker loses a full eight hours of sleep over a week. But bright-light systems cost upward of $100,000, so it'll be some time before they get installed in a typical factory or all-night convenience store. And bright lights wouldn't do much good in a police cruiser or the engine of a freight train. So researchers are looking for other solutions.

At Stanford University's Sleep Research Center in Palo Alto, California, there's a laboratory that can monitor the sleep and waking patterns of up to 80 animals at one time. Physiologist Dale Edgar is studying how certain medications affect the circadian rhythms of lab rats. These drugs may help sleepy humans stay alert. Each rat is wired to a stack of electronic sensing gear.

DALE EDGAR: Each one of these computers is currently handling about eight animals. That computer screen is indicating whether or not the animal is drinking a water spout or moving around inside their cage. And--

STEPHEN SMITH: Looks like of these eight rats, you've got one, two, three that are awake. Oops, number six just went to sleep. Oh, number one just went to sleep. These guys move fast.

DALE EDGAR: [CHUCKLES] Yeah, they have rapid transitions between sleep and wakefulness. They can be asleep and have a brief arousal, just like people can have brief arousals in sleep, that last 10 seconds, 20 seconds, sometimes a minute or so.

STEPHEN SMITH: As all-night sleepers, humans are relatively unusual in the animal kingdom. Rats and most other creatures sleep and wake in shorter bursts, perhaps to avoid getting gobbled by predators. Dale Edgar says that scientists don't know for certain why humans sleep. The most they can say is that we sleep because we get sleepy.

Edgar notes that animals with the least to fear from predators, like lions and humans, sleep the longest at a stretch. It may also have something to do with how vigilant we are when we're awake.

DALE EDGAR: In order for us to function optimally and to perform optimally, meaning be very competitive at certain times of the day, there's a metabolic and physiological cost. And sleep pays back the debts, the energetic cost to the body and the brain, as a function of these very, very high levels of vigilance. It's likely that if we didn't have these high levels of vigilance, we might not as a species have advanced as far as we have.

STEPHEN SMITH: To help night workers fend off that natural urge to sleep, Edgar is studying medications that might temporarily bypass the circadian timekeeper, without the risk of addiction and other problems caused by conventional stimulants. A pill to temporarily boost alertness could be especially helpful to people in jobs like long-haul truck driving. They suffer the most fatal highway accidents in those sleepy hours of the early morning.

[MUSIC PLAYING]

[DOOR OPENS]

SPEAKER: Good afternoon.

MYRNA PATTERSON: Oh, hi. Good afternoon. This is Dart with a inbound.

STEPHEN SMITH: Myrna Patterson is a 30-year veteran of the road. This year, her lifetime trucking odometer will click its 3 millionth mile.

SPEAKER: (ON RADIO) Just come down and park away in your truck, OK?

MYRNA PATTERSON: All right, got you. Thank you.

[BUZZING]

STEPHEN SMITH: Myrna's has just finished a two-day trip, from Minneapolis to Fountain Inn, South Carolina, hauling paper and hazardous chemicals. So far, she's getting pretty good sleep. But then comes a tough assignment from dispatch. It's 4:30 PM, and they need her to turn around and drive through the night.

MYRNA PATTERSON: Well, I have a real stupid question to ask you. If I didn't take this load, would there be any other loads available? Right, right. [LAUGHS] Thanks. Bye.

[HANGS UP PHONE]

STEPHEN SMITH: Myrna agrees to haul 78,000 beer can lids to Trenton, Ohio, by 7:00 the next morning. She could refuse to drive at night. But Myrna needs to stay on the good side of her dispatchers, so she says yes.

[ENGINE RUMBLING]

Federal regulations limit truckers to 10 hours behind the wheel in any 24-hour period. Myrna's already burned up six hours of drive time today. So she can't motor straight to Ohio without stopping for sleep. If her driving logs don't add up right, she could pay a big fine. Myrna plans to juggle sleeping and driving to stay just within the law.

[HISSING AIR]

But first, a flat tire blows her schedule. And then there's a long aggravating delay at the aluminum can factory. So Myrna catches a brief nap before midnight, drives a while, sleeps a couple of hours, drives again.

MYRNA PATTERSON: When I first come out on the road, all the old salts told me, oh, the day hangs heavy. It's just before dawn. Yeah, right, uh-huh.

And then I noticed that I was starting to get sleepy. So now I'm one of the old salts.

[LAUGHS]

STEPHEN SMITH: At 5:30 AM, just outside Roanoke, Virginia, Myrna sets her obnoxious talking alarm and beds down for a final snooze.

[DINGING]

AUTOMATED VOICE: 7:30 AM.

MYRNA PATTERSON: Oh, that mattress feels good.

STEPHEN SMITH: This kind of hard driving would weary the bones of even the youngest truckers. Myrna is 55 years old. The federal rules regarding hours on the road remain substantially the same as they were when written in the 1930s. No one was thinking about circadian rhythms back then, or even the quality of sleep.

Myrna hates this kind of patchwork all-night driving. Years ago, she nearly died when she crashed into another truck during the pre-dawn hours, when the brain tends to be the most sluggish. Many long-haul truckers have a strategy to outwit sleep, like taking brief naps at a truck stop or a rest area. Some researchers are studying the science of napping.

[ENGINE IDLING]

SPEAKER: Is there a throttle control?

SPEAKER: Yeah, that's the throttle control.

STEPHEN SMITH: This is a Boeing 747 flight simulator at NASA's Ames Research Center in Palo Alto.

AUTOMATED VOICE: Light float.

STEPHEN SMITH: Scientists here study how commercial airline pilots are affected by jet lag and irregular work schedules. NASA recommends a number of strategies to fight off pilot fatigue. Research chief Mark Rosekind says, the most simple method may be the most controversial. While one pilot flies, the other one takes a brief nap in the chair.

MARK ROSEKIND: Brief naps are extremely effective in helping to promote good performance and alertness. And whether you take a nap before a period where you're going to be awake for a long time or in the middle of being awake for a long time, the nap really helps to improve your performance and alertness.

STEPHEN SMITH: The timing and duration of the nap could be critical. Rosekind warns that a nap that's too short or too long may not work. Now, hang on.

Napping on the flight deck? How are passengers going to feel about a snoozing pilot? And what about all that macho military talk about pilots having "the right stuff"?

To repackage sleep as a sign of strength, NASA calls it a personal performance enhancer. Mark Rosekind says, pilots and everyone else in our sleep-starved world need a new outlook.

MARK ROSEKIND: Rather than seeing sleep as a negative thing, how it takes up time, it's a waste of time, napping means you're stupid, lazy, dumb, et cetera, sleep is actually a very powerful tool for people to help manage their performance and alertness when they've got to get their job done.

STEPHEN SMITH: The Federal Aviation Administration, which sponsored some of the NASA research on pilot fatigue, has yet to approve so-called "strategic napping" in the air.

[DRUMMING]

Will our modern 24-hour world force humans to evolve a reduced need for sleep? Can we afford to wait for our biological clock to sync with our cultural clock? That might take millions of years.

Our mass excursion into the night, guided by the glowing filament of an electric bulb, is little more than a century old. Some have called this nocturnal time migration the crossing of a new frontier. Researchers appear to be closing in on ways to make the night shift more tolerable.

But as they develop new techniques, sleep researchers also warn we can no sooner dispense with sleep than shed our biological need to eat. If anything, we should all be sleeping more. So get comfy and catch as many winks as you can.

SPEAKER: Working Nights was written, produced, and mixed by Stephen Smith of Minnesota Public Radio. Additional reporting by Stephanie Curtis, production intern Charles Maynes. The music was by Bill Frisell. This program is a production of Minnesota Public Radio, in collaboration with Soundprint, the weekly documentary series on Public Radio.

GARY EICHTEN: Cassette copies of the documentary Working Nights are available. Send a check for $12 to MPR Tapes, 45 East 7th Street, St. Paul, 55101. And you can also visit our website at www.npr.org.

Well, Stephen Smith has joined us now in the studio to talk a little bit more about Working Nights. And also joining us today, Dr. Gerry Rosen, who's with the Minnesota Regional Sleep Disorders Clinic at the Hennepin County Medical Center. And we invite you to join our conversation today, especially those of you, if you're one of those millions of people with night shift experience. Give us a call. Love to talk with you today.

227-6000 is our Twin Cities area number, 226-6000. Outside the Twin Cities, 1-800-242-2828. 227-6000, 1-800-242-2828.

Stephen, Dr. Rosen, thanks for coming in today. Appreciate it.

STEPHEN SMITH: Good to be here.

GERRY ROSEN: It's a pleasure.

GARY EICHTEN: Dr. Rosen, some people obviously take this problem seriously. Do most people?

GERRY ROSEN: Now, I think most people don't. That-- what was pointed out on the documentary is most people view sleep as optional, and that they are free from the constraints that sleep really imposes. So I think the general attitude is that one can shift around when one sleeps and how much one sleeps without suffering a lot of consequences. And that's just not correct.

GARY EICHTEN: It does seem, though, that different people have different requirements for sleep. I mean, it looks like some people can really get by with an hour or two of sleep and function quite normally.

GERRY ROSEN: Well, not-- certainly not functioning optimally. That there is a-- there's a range of how much sleep people need. The majority of people really do-- a majority of adults really do need about eight hours. And if they get substantially less, then they're going to suffer some consequences.

Now, they may be able to compensate for that. But they'll likely be doing less well than if they get the amount of sleep that their body needs.

GARY EICHTEN: Stephen, was this-- sounds like a fun project to work on.

STEPHEN SMITH: Well, it was interesting. It kept me up nights.

[CHUCKLING]

GARY EICHTEN: As it were.

STEPHEN SMITH: As it were.

GARY EICHTEN: As it were, uh-huh. What's more difficult, to work an all-night shift all the time or changing shifts?

STEPHEN SMITH: Well, the research suggests, and I think it's both the scientific and the-- just the anecdotal research suggests that people who work a steady night shift get more acclimated to it in general than people who are working rotating shifts, meaning you work a week of nights, then you work a week of swing shift, then you work a week of days or something like that, because, I mean, it just makes common sense. If it's a tough schedule, at least you can get into some kind of groove. And over time, you will adapt as much as possible.

The problem, Gary, is that even people-- according to the research that I've done, even people who are on a continuous night shift-- and they are actually in the minority. That's-- it's not common among shift workers to be on a permanent night shift. It's becoming a little more common-- that even those people have a hard time fully adapting to the schedule.

The real issue is not, it seems to me, as much staying awake while you're on the job, which is difficult enough. The real issue is sleeping when you get home because as was pointed out in the piece, you can fight off the sleep, but it's really hard to fight off being awake. And if you've ever tossed and turned, trying to get to sleep when you're really tired but you just can't, that's what often happens. People get truncated sleep.

They come home. They collapse. They sleep until about noon or 1:00, very common response among shift workers.

I get to sleep-- first thing when I get home, maybe within an hour. And then I sleep until about noon or 1:00. And then I'm up. And maybe I'll nap before I get to work again, but that's about it.

So they're getting six hours, some five, six hours of sleep regularly. And according to people who study this, and according to sleep experts like our colleague here, our guest here, after a while, it just builds up. And what, I think, Charles Czeisler said in the piece, which I found very interesting, was that we've become accustomed to being less alert, less on the ball than we could be.

And he's found that when people actually do start getting enough sleep, sometimes for the first time in their adult lives, he describes it as a shade lifting on a window, where suddenly you are aware of a world of alertness and awakeness, which by the way, Gary, is a world I wouldn't mind visiting some day.

[CHUCKLING]

GERRY ROSEN: No, the reason that it's hard to shift one's schedules back and forth like that is that what's driving our sleep-wake schedule is this circadian pacemaker that's sitting in the small nucleus in the base of the brain. And this pacemaker doesn't make sudden big jumps from day to day. It can shift an hour. It can shift a day but can't shift a lot more than that.

So if one's schedule suddenly jumps eight hours, that-- the pacemaker is never going to catch up that quickly. So you're always going to be off. And the experience of jet lag is that when you are sleeping on a different schedule than your internal pacemaker.

And for people who are doing either quickly rotating shifts, or which is-- what is very common, individuals who work maybe a steady night shift during the week but on the weekends then sleep nights and are up days so they can spend time with their families, they never end up fully shifting this internal pacemaker. So they're always functioning as if they're partly jet lagged. And that's what-- that's why they're never running on all cylinders, as Stephen was describing.

GARY EICHTEN: And it sounds like the timekeeper really keeps track of two things, in a way, number one, the thing that can be reprogrammed to some degree if you were on the same shift all the time, but then the business of night and light?

STEPHEN SMITH: Right.

GARY EICHTEN: It gets confused about that, too?

STEPHEN SMITH: It gets its clue as to when you should be awake and when you should be asleep based on light. It takes its clue from the eye. Interestingly enough, it's actually not the, if you will, the optical part of the eye. It's not the seeing function of the eye that's at work here.

It's like how your ear does two things. Your ear is in charge of hearing and in charge of the inner ear in charge of balance. The eye apparently has this connection to the nucleus of cells that Dr. Rosen was describing.

And people who are totally blind, without vision, still get signals from the eye to reset the pacemaker. And sometimes, when blind people have had eyes removed for infectious or cosmetic reasons, they end up having profound sleep disorders because suddenly the clue, the cue going to that internal pacemaker, which is light, is no longer there. So the pacemaker doesn't know if it's day or night, night or day.

The other system, Gary, is that system which builds up and releases your sleep load. And that's a separate system and one that the scientists know a lot less about, actually.

GARY EICHTEN: We're talking today about working nights and sleep and sleep disorders. If you'd like to join our conversation, give us a call. 227-6000 is our Twin Cities area number, 227-6000. Outside the Twin Cities, 1-800-242-2828.

Stephen Smith is here, the producer of our documentary. Dr. Gerry Rosen is with us. He is with the Minnesota Regional Sleep Disorders Clinic at Hennepin County Medical Center. Janet, thanks for calling in. Go ahead, please.

JANET: (ON PHONE) Hello, I have a question about sleep apnea. I have a friend who has sleep apnea. And he's been on Prozac for two years, which doesn't seem to be helping him at all.

And he's done things like use Breathe Right strips, just to help prevent snoring. But he has heard recently that St. John's wort might be something that he could use. And I also wonder what role things like ritual play in getting to sleep, you know, brushing your teeth, getting undressed, what role that plays in having a good night's sleep.

GARY EICHTEN: OK, Doctor?

GERRY ROSEN: OK, well, let me take them one at a time. Sleep apnea is a clinical problem that's caused by a partial collapse of your upper airway. And what happens during sleep apnea is you actually stop breathing. Your body continues to try to breathe, but you're not getting any airflow, and that you awaken because of the-- of not having-- not breathing, and that your sleep will be very disrupted by this problem.

Now, it-- the Breathe Right strips will open up the front of the nose. But they really don't help with patients with sleep apnea because the area of the collapse is in the back of the throat, typically. Medications have not been shown to play any role in helping sleep apnea.

So either prescription medications or herbal medications are unlikely to help someone who has obstructive sleep apnea. And they really need both to be assessed in a sleep disorder clinic and to be treated. The recognition of this is important because the treatments are very effective, very safe, and make a huge difference in the quality of a person's life.

GARY EICHTEN: Rituals.

GERRY ROSEN: Rituals play an interesting role because that in order to fall asleep, we need to lower our level of arousal, that there are lots of signals that we have that sleep is coming. We need to be in a place that is safe, that's comfortable, and that, as humans, the way we establish that set of circumstances that tell our brains that a place is safe is through these rituals. So they often play a very important role.

And that's part of the reason why when you're sleeping in some place different than you usually sleep or with a different bed partner or sometimes just a different pillow, that you can find that you can't fall asleep. And the reason is that your level of arousal just doesn't lower as it needs to in order to make that transition from wake to sleep, and something that both children and adults experience. And there's a lot of variability. So some individuals are much more sensitive to the effects of those rituals than others are.

GARY EICHTEN: I was going to say, some people seem to be able to fall asleep anytime, anywhere. No matter how much they've slept, they're out like a light. How can that be?

GERRY ROSEN: Well, a likely bet is that as a society, most Americans are at least somewhat sleep deprived. And my guess is most of those people who are able to fall asleep any time, any place have been chronically sleep deprived and that they're able-- they've got this sleep pressure that is building up behind them. And every time they lower their arousal a bit, they're able to drop off to sleep.

There are also some medical conditions where the primary symptom is daytime sleepiness, where you're falling asleep in a variety of settings.

GARY EICHTEN: We'll talk later. [LAUGHS] Robin, go ahead, please.

ROBIN: (ON PHONE) Yes, I have a comment for Dr. Rosen, and maybe he can give me his opinion. I worked the night shift years ago. And I noticed that when I got off work and came home, I would get about five hours of sleep.

But the whole time, it was like a daydream. And I would be awake, but yet I was dreaming at the same time. And I couldn't tell reality from sleep. And I was wondering if that happens to people that sleep the day shift.

GERRY ROSEN: Well, that dreams are a part-- your sleep is made up of several different types of sleep. And one is dream sleep, or what scientists call REM sleep or Rapid Eye Movement sleep. And there's a very clear rhythm of how your dream sleep and your non-dream sleep are woven together, which make up your full night.

When someone works a shift that not only is your total sleep disruptive but the integration and the weaving of your dream sleep and non-dream sleep are disrupted, and so one experience that people have is just like you're describing, is that you may well be having this dream sleep but during the day, which is not usually the case. Generally, this is a sleep that you have at night. And if you're being awoken out of this dream sleep, then you're going to be much more aware of the content of the dream. So your net-- the net result may be just feeling like you both haven't slept well and that you've been working all night in your-- and all day with these dreams.

GARY EICHTEN: Stephen?

STEPHEN SMITH: One of the things I found interesting in this question about dreams-- and it is-- it seems clear from the research that the quality of sleep is critical to how you feel. And part of that quality, the essential-- one of the essential components of something being a good quality sleep is getting the right kind of dreaming stages fulfilled, if you will. One of the things I found interesting was the natural history of sleep and wakefulness.

The-- as I said in the documentary, the circadian pacemaker is in a part of the brain which from an evolutionary point of view is very ancient. And I know that the science is still a bit fuzzy on this. But I was interested in the fact that it could be that REM sleep, this important stage of rapid eye movement, where your body is-- your mind is actually more awake, in a way, than it is asleep, if you compare it to the deeper stages of sleep and other things that are happening, also may be related to some of the older parts of the brain.

This has led some scientists-- and we're going out on a limb a little bit here-- but has led some people to speculate that both of these things are linked to our primitive ancestors and that, in fact, some of-- it comes down to the fact that we still don't know why we sleep, really. We don't know why we dream. We're not really sure what the physiological functions of those are.

But it's interesting to think that REM sleep and that kind of dreaming that we need so desperately to be stable, healthy people may be one of the oldest vestiges of our mind, if you will. Like I say, that's a little bit out on the limb because it's pretty hard to trace that down. But I found it fascinating.

GERRY ROSEN: Yeah, it's very hard-- it's hard to understand the significance or the reason for the different types of sleep, that we know that dream sleep is something that's been wired into the evolutionary process, going back as far as reptiles. When you get to fish, they don't have what we understand as dream sleep. But once you move from fish to reptiles, you actually see the preliminary of this dream sleep. So it's something that from an evolutionary perspective has been there, really, for eons, though the significance and the reason for it is something that we're still trying to understand.

GARY EICHTEN: Ben, your question, please.

BEN: (ON PHONE) Yeah, actually, I have two questions. I work as a commercial Illustrator. And when I'm on a project, I often stay up very late or sometimes even all night. For instance, last night I got to bed at 4:30.

The question that I had, I often find that in the evening, around 7:30 or 8 o'clock, I have a real sinking spell. And if I push through that and get my mind charged up again, I can have a burst of energy that will last till much later. And I'm curious as to what's going on there.

The other question I have is about sleep debt. They say if you don't get enough sleep, then that kind of accumulates in your body. Is there a limit to how much you accumulate?

Or does it just keep-- I was thinking of the example of the truck pulling the trailer. Do you-- is the trailer finally full? Or do you just trade in for a bigger and bigger trailer? And if I want to get caught up, do I-- does that mean I have to go to bed for five years?

STEPHEN SMITH: Right.

GERRY ROSEN: You can empty the trailer. I would suggest a week's vacation, where you can sleep ad lib as much as you want, where you're able to sleep at night without any constraints and can get up whenever you want the next day. And after a week, you should have-- you'd be pretty much caught up. And your trailer should be empty, and you can start over again. Where you take that vacation is optional.

The question about this change in your level of alertness is a very interesting phenomenon of the circadian system in that our level of alertness during the day is not steady. But typically, there is this variation, just as you described. And typically, what will happen is you wake up in the morning. And you'll be awake and alert.

If you're on a day shift, you'll continue over the course of the day, slowly maybe maintaining a reasonable level of alertness. And then sometime in the late afternoon-- and that-- when that is varies a lot with the individual. It may be right at 1:00 or 2:00. It may not be until 3:00 or 4:00 or 5:00. You'll have this dip in alertness, and that's the siesta time, where in many cultures you'll take a two-hour nap.

If you-- once you get through that, even though you've now gone-- without a nap, once you get through that, your level of alertness increases, even though the amount of time that you've gone without having slept is, in fact, longer. But there's a circadian increase in your level of alertness. And this will increase until you have a dip again around bedtime.

So I'm sure what you're experiencing is you've got this circadian dip in your alertness that's happening 4:00 or 5:00 in the afternoon. And once you get through that, you have this burst of energy. And you're able, it sounds like, to maintain that for some time. But that variation in the late afternoon is a very typical feature of a circadian rhythm.

STEPHEN SMITH: When I was writing this piece, Gary, I would often-- I was working into the evening a lot. And I could do some pretty clear writing up until-- between 7:00 and 10:00 was a really productive period. But for me, 10 o'clock, boom, the car shuts down, and I was dead. And I could stick around, and I could keep working. But I discovered that the-- what I got done wasn't particularly useful, especially not minute per minute compared to the period where I was really cranking a few hours earlier.

GARY EICHTEN: Mm-hmm. Carrie, your question, please.

CARRIE: (ON PHONE) Yeah, a while ago, I read an article on sleep deprivation and why people would eventually die from lack of sleep. And their theory was that the brain required a substance called glycogen to function well. And they also believed that glycogen is manufactured during sleep. So if a person isn't allowed to manufacture the glycogen, the brain would become impaired, and eventually the person would die. I was just wondering if you had heard about that kind of effect or if you thought it had any effect on sleep deprivation.

GERRY ROSEN: Well, there are a number of theories. None of them have been well proven. And in animal experiments, they've shown-- and this is with rodents primarily-- that death will be the end product of continued sleep deprivation.

In humans, what will happen is that your brain will go to sleep, regardless of what you try to do. So you end up having micro-sleeps. And when people have attempted to have long periods of wakefulness, then regardless of how hard they tried, they will-- their brains will switch over into sleep completely beyond their control.

I think the theory about the glycogen deprivation is one of a number. But really, none have been well demonstrated in-- even in animals. And really, that hasn't been even-- it's even less well understood when it addresses humans.

GARY EICHTEN: Mike, your question for Dr. Rosen and Stephen Smith.

MIKE: (ON PHONE) Yeah, I have a couple of observations and then a question. I used to work rotating shifts for a formerly large computer company of Minnesota. And I found that in the middle of the night when you did get unproductive, that a 15- or 20-minute nap and a couple of doughnuts and a Coke, and then you're really ready to go again for a few hours.

In fact, in a time like that, I-- because fixing computers is an intellectual challenge. And when you're done, you can look back and see how hard the problem was and how smart you were. I had the impression that I got more creative and smarter in that little zone after a nap and some doughnuts than even I was in the daytime.

And I'm wondering if maybe that's why-- cops and doughnuts are almost a cliche.

[LAUGHING]

I'm wondering if these guys aren't sort of self-medicating themselves, trying to stay awake. And the other observation was that if you go to any workplace at 3 o'clock in the morning and look around, you can see who the important people are. In the daytime, all the dead wood and the obstacles come in, but that's a personal opinion.

The question actually is, I've read that older adolescents, circadian rhythms shift. And my question is, Are we-- when we send them to school early, are we starting them in the middle of the night shift, as far as they're concerned?

GERRY ROSEN: Yeah, that is precisely the issue and the reason behind the change in school start times that is happening here in Minneapolis, that there is an animal model that demonstrates the same thing, that this internal circadian pacemaker tends to drift later during adolescence. So if-- even if they weren't staying up with their friends, listening to music, that-- and they were left in a dark room, their natural circadian rhythm would have them going to bed later and waking up later. That natural drift is often exacerbated by the behavior that the adolescents engage in, which is staying up later doing either social activities or because of work or because of homework.

And you're exactly right. By having them get-- start school early, we really are asking them to start functioning in the latter part of their circadian night. And that explains why if you go to a public-- you go to any high school at first period in the morning, you look around, and you'll see a lot of dozing folks and a lot of heads down on the table.

GARY EICHTEN: Any magical quality to doughnuts? Or is it pure coincidence?

GERRY ROSEN: Well, I think it's a-- probably, the coffee is the better association because coffee is a-- the caffeine is a stimulant. And that will help. I think the doughnuts is probably-- gains from the association with the coffee.

STEPHEN SMITH: [CHUCKLES] It's a psychological fuel. I just should say, in Don Banham's defense, the fellow early on in this piece, the police officer I drove around with, he's a power lifter. And the last thing he's going to eat in the middle of the night usually is doughnuts.

But it's also true that the body's digestive system shuts down. And so if-- as many cops and other night shift workers know to eat their meal early on in the shift because if you try to eat anything really heavy about 3:00 or 4:00 in the morning, it really just sits there.

GARY EICHTEN: Mm-hmm. Couple of other quick questions here before we run out of time. If you are assigned to work overnight, is it best to go to sleep immediately when you get off work? Or should you sleep before you go to work? Because a day worker, of course, would stay up after they get home. And then they'd sleep and go-- get up and go right to work.

GERRY ROSEN: I think the decision about when to sleep mostly is going to be an individual one. And has to really pay attention to your own body rhythms. Part of that is our circadian pacemaker won't be pressed and pushed very easily, so that regardless of when you want to sleep, if your circadian pacemaker is not set towards sleep, then you're not going to, unless you've had severe sleep deprivation. So I think probably the most important advice is paying attention to how your body feels, and then once you do go to sleep, trying to ensure that the environment is going to be conducive to sleep, both light attenuated and sound attenuated.

GARY EICHTEN: And do more employers seem willing to let people sleep on the job now, to give them that little nap?

STEPHEN SMITH: Well, Gary, this is a growing interest. I--

GARY EICHTEN: Certainly around here it is.

STEPHEN SMITH: Well, I know. And some of us have been doing it for years. No, I would say that they are-- the one sign that there might be some progress in this department is that there are actually consultants who travel around the country convincing top executives, who like to work late into the evening and get up early, that it's not only OK but powerful to nap during that post-lunch mortem that we're all familiar with.

GARY EICHTEN: Thanks a lot for coming by today. Really appreciate it. Dr. Gerry Rosen, who is with the Minnesota Regional Sleep Disorders Clinic at Hennepin County Medical Center has been our guest today. Stephen Smith stopped by, the producer of our new documentary Working Nights. And you can get a copy of that by sending a check for $12 to NPR Tapes, 45 East 7th Street, St. Paul, 55101.

We will be rebroadcasting the program, by the way, at 9 o'clock tonight. Programming on Minnesota Public Radio is supported by the Humphrey Institute Policy Forum and American Express Financial Advisors, sponsoring Senator Alan Simpson's luncheon address on Social Security reform June 11, 625-8330.

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