The Time Of Our Lives 1990 science documentary

body time increasingly in so many ways we've come into conflict with the ancient rhythms of the environment we evolved in rhythms that we still carry inside ourselves in our biological clocks in that sense we're literally old timers trying to march to the beat of the modern drummer in this program you'll meet scientists who are beginning to find ways to help us get back in step and perhaps create a new harmony between the time in our bodies and the time on our wrists [Music] los angeles internat

ional airport midnight thousands of passengers and flight crews are preparing to be launched into distant time zones when they arrive at their destinations they will reset their wristwatches but what about their biological clocks nothing in their evolutionary history has prepared them for such a dislocation in time on the ground though they will cross no time zones workers beginning the graveyard shift are also defying their evolutionary heritage trying to stay alert as their bodily rhythms dwin

dle down to a nighttime low physiologist martin moride the statistics tell us that human errors are far more likely occur in the wee hours of the morning they tell us that beau paul occurred at one o'clock in the morning three mile island or four o'clock in the morning chernobyl at 1 20 o'clock in the morning we tell us the truck drivers are five times more likely to fall asleep at the wheel and come off the road at five o'clock in the morning than they are at the 24 5 hour average and so on and

so forth so what we found is that major events and major accidents and particularly catastrophic accidents which involve human error much more probable at that time those are dangerous hours ironically danger is precisely what our biological clocks were designed to avoid they evolved in a world of natural rhythms where day follows night tides ebb and flow season follows season to all species this is life or death information being in the right place at the right time can mean the difference bet

ween survival and extinction it's a fact of life that evolution has tended to fashion organisms that are attuned to nature's rhythms and have evolved mechanisms that keep them in sync with their environment ed crub director of the griffith observatory in los angeles these animals like ourselves had to respond to this same earth this is an earth that's turning around on its axis every day this is an earth that's going around the sun every year and changing seasons yeah an ice age comes and goes a

nd things get a little chilly for a while or maybe it gets a little steamy in the jungle but those creatures and those plants have been responding to these natural changes in the environment which are a product of this earth and however long it's been going on spinning the way it has and moving the way it has we are part of that overall pattern we are part of nature it's not a bit surprising that our behavior too is a response to those fundamental cycles although our lives now seem to be dominat

ed by the times and the timers that we have made we are captivated by the times that made us to an archaeoastronomer like ed crub who studies the calendars of past civilizations those ancient signals still have emotional power you can of course immerse a late urbanized 20th century human being back into the mountains for a sunrise say on the winter solstice again and it becomes a glorious moment for that individual they they rediscover the fact that the sun comes up and it's beautiful and it has

all of the meaning it always had which is renewal the chance to start over a new day for scientists pioneering the new field of chronobiology the light dawned when they began to realize that natural cues like sunrise have another kind of power they orchestrate our biological cycles [Applause] to get a better understanding of our rhythms scientists started what you might call an underground movement volunteer subjects spent months in caves isolated from signs of the time there were no telltale p

atterns of dark and light no sudden fluctuations of temperature and none of those social clues that we use to gauge daily time oh and no clocks they were free to set their own schedules to choose what time to eat sleep read and so on meanwhile on the surface researchers were monitoring their vital signs to see what kind of rhythms the body settles into left to its own devices they discovered we have characteristic cycles of such things as heart rate body temperature and hormone levels in other w

ords the beat goes on question what's keeping the beat what's keeping track of time when our body is cut off from environmental cues only one answer seems to make much sense we must have some kind of an internal pacemaker a biological clock that's orchestrating our daily rhythms [Music] of course we have no clocks of springs and cogs but our biochemical counterparts do the equivalent job of keeping us up to the minute many cycles in the body repeat every 25 hours or so we call these rhythms circ

adian from the latin for about a day our body temperature rises and falls once a day and so does our strength and the keenness of our sense of smell these and other daily cycles are elegantly coordinated in the body if we think of each of these cycles as a player in the biological orchestra then we are in a sense a symphony of rhythms one of the most remarkable findings in this field has been that this incredible array in rhythms and everybody function is actually orchestrated by one key pacemak

er there are other clerks other secondary clocks but one key pacemaker which turns out to be a cluster of nerve cells no more than a third of a millimeter in size in the human brain it's a tiny little cluster of nerve cells located in the hypothalamus in the one of the older areas of the brain it's called the suprachiasmatic nucleus the suprachiasmatic nucleus or scn is responsible for our feeling sleepy at night and alert during the day it sets a beat for kidneys heart lungs and other organs [M

usic] some of the body's rhythms don't depend entirely on the scn the adrenal glands for example appear to have a separate clock controlling the daily secretion of the hormone cortisol [Music] so even without the scn solo instruments of the circadian symphony may still be able to play their parts [Music] but they wouldn't be able to keep time with one another for that the body needs a conductor many scientists believe the scn is the principal conductor of the body's daily rhythms why do scientis

ts think the body's key clock is located in the scn because when you transplant it from one animal to another it keeps on ticking [Music] fred davis is a neurobiologist at northeastern university what we've been able to do is take the area of the brain that we believe contains this a discrete structure that generates circadian rhythms for for many functions within the animal and we have been able to transplant that to another animal and give it the rhythmicity of the donor animal removing the sc

n destroys a hamster's regular daily pattern of activity and rest each line of this graph represents a day in the life of a hamster the dark bars show when the hamster runs in its wheel without an scn the hamster scampers about at odd times shown by the erratic pattern of bars but after an scn transplant shown by the letter t the animal begins to pick up a beat [Music] gradually activity moves to about the same time each day and the dark bars cluster into a single column what's more the animal p

icks up the donor's rhythm two university of virginia scientists discovered a mutation in hamsters that produced an unusually fast biological clock davis and these scientists replaced a normal hamsters scn like the one you can see here with the speedy scn the normal hamster quickly picked up the distinctive tempo of the mutant [Music] what's the point of a built-in pacemaker well it can give you the same kind of jump on the day you get with an automatic coffee maker with this gadget you don't ha

ve to stumble around in the morning making coffee it's brewed and ready to go when you get up and in the same way with a biological clock you don't have to waste the first part of the day brewing neurochemicals to rev up your body and brain you can trigger an event such as warming up the body to daytime levels appropriate for daytime metabolism despite the fact it takes two or three hours to warm the body up to daytime levels if you know when door is going to occur so it's those pre-dawn signal

from the biological clock that starts all the processes getting you ready for the day ahead and so that makes you less vulnerable when the day occurs it makes you more efficient it makes you more tuned up and raring to go when morning occurs then let's say if you didn't have that clock and you had to start the processes going guided only by the external cues of dawn and dusk of course we don't all warm up to the new day in exactly the same way some of us are owls people whose daily temperature c

ycles peak relatively late in the day others are larks morning people who have their temperature peaks earlier most of us are somewhere in between in the mainstream which certainly makes it easier to organize a society but you do need something else schedules the bodies may be willing but the souls usually need some temporal guidance said benedict knew all about that [Music] [Music] remember that old children's song pharaoh jacques frerajaka dormevu dormevu brother john brother john are you slee

ping are you sleeping sound the matins sound the matins ding ding dong [Music] ding ding dong the song harks back to an age when being in the right place at the right time meant being in church for morning prayers for matins and brother john's duty well he had to wake up in time to summon the faithful by ringing a bell [Music] in benedictine monasteries in the middle ages the ringing of bells was well regular as clockwork idleness wrote saint benedict was an enemy of the soul time was sacred bec

ause it was god's time and the monks used it to the full they prayed according to a strict schedule that's still largely used even today in modern monasteries like this one in oceanside california [Music] [Music] in the forerunners of monasteries like this mechanical clocks first made their appearance sometime around the year 1300. for the benedictines it was in a sense of liberation because it made it so much easier to keep track of time than following the sun or moon and yet it could be argued

that in those early monasteries technology first begins to conflict with biology [Music] it wasn't long before clocks came out of the cloisters and into towns and villages gradually urban life became organized around the regular ticking of man-made rhythms and eventually we carried the beat to a new frontier we colonized the night [Music] this has become a 24-hour society where every second counts because time is money it really began here the invention of electric light allowed factories to ru

n around the clock and they did steel workers toiled a 12-hour shift seven days a week with one day off a month even today's 40-hour week can be a hardship particularly for the more than 20 million americans whose schedules shift between day and night [Music] trying to work when your biological clock is telling you to sleep can be a struggle as the pilots of this china airlines flight learned this computer simulation shows the boeing 747 near the end of an 11 hour flight it was a little after 2

am according to the captain's biological clock near the daily low point of human alertness and that may have been why the crew became distracted by a minor engine problem and lost control of the plane it rolled and nose dived falling about six miles in two minutes before the pilots regain control [Music] images of technology gone astray are one reason why some of us yearn for simpler times it's why places like this exist old sturbridge village in massachusetts recreates new england life of the 1

830s [Music] [Applause] [Music] [Applause] [Music] this is the beat of a bygone era a time when you moved only as fast as your horse could carry you it could be a rough ride but there was no jet lag [Applause] [Music] our circadian mechanism ran beautifully for most of the time we've been on earth keeping internal time in harmony with external time when the pace of life was slow our biological clocks had plenty of time to adjust during a journey across time zones no one ever complained of wagon

lag but jet lag is a problem it can take over a week for the biological clock to catch up to its new location in fact that's one way we discovered that we have biological clocks something was out of sync [Applause] our technology may let us leapfrog over time zones but our biology brings us back to earth we've got to realize that we've got a highly sophisticated complex piece of machinery the human body and the human brain which was designed under a different set of design specs that we're now o

perating it if you purchase a complex piece of machinery you better believe your job is on the line if you run it outside of science specs if you run it too many revolutions per minute if you if you don't oil it if you don't um keep it at the right temperature and conditions we're doing exactly the same thing with the human body we're taking a piece of machinery that was not designed for this around the clock lifestyle and requiring it to perform and then wondering why it fails if the problem is

in the body's timing mechanism then that's what we have to understand first does the scn which is the body's chief pacemaker do the same kind of job as the uh timer in this coffee maker let's think about it for a minute imagine that this machine had to have the coffee brewed not at seven o'clock in the morning but at sunrise every day whenever that happened to be because that's closer to what our internal clock does it helps us get perky by sun up now the trouble is that sun ups at a different

time every day it's not always seven o'clock so what we need is an internal clock that can keep track of that time and be reset every day somehow our clock has to get a signal from the environment that says tomorrow start brewing those wake up neuro chemicals a bit earlier or later now how does it get that signal for years scientists struggled to find the answer when they discovered it it made perfect sense it's light charles seisler is a circadian physiologist at boston's brigham and women's ho

spital it used to be thought that human beings were relatively insensitive to exposure to the light dark cycle that our internal biological claw couldn't be reset by exposure to light but was instead synchronized by social contacts between people and that research was really based on experiments which had design flaws and when we repeated those studies and increased the intensity of the light exposure we found that that the light dark cycle is indeed the most powerful synchronizer of our interna

l biological clock and that properly timed exposure to bright light and darkness can lead to resetting the internal biological clock to any time zone within two days this was a crucial discovery dramatically extending the results of an earlier experiment of sizeless in the late 1970s he showed that the human clock could be reset slowly by an hour or two a day with dim light the unit that scientists use to measure the intensity of the light you're exposed to is the lux if you're one meter away fr

om one candle you're exposed to one lux if you're under a full moon you're exposed to about a third of a lux and in your office you're exposed to just a few hundred lux here i'm exposed to about two thousand lux this is between four and five thousand lux this is about seven thousand lux and this is about ten thousand lux outside under the midday sun you're exposed to about one hundred thousand lux in sizeless new clock resetting experiment he used 10 000 lux about the intensity of a sunrise this

time he found the human clock had a fast reset feature it can be switched to any time zone within a few days we have now demonstrated for the first time exactly what the response is to light depending on the phase at which we give the light or what time of day it is in the body when we administer the light stimulus so that we can now predict with with accuracy the nature of the resetting response to a light stimulus depending on when we give the stimulus and just as in animals there are some ti

mes of day when exposure to very bright light 10 000 lux of light for a number of hours has no resetting effect at all there are other times of day where it can reset the internal clock by 12 hours reversing day into night the basic idea here is really quite simple like this swing the biological clock is an oscillator something that repeats regular patterns and just as the pattern of this swing can be shifted by giving it a push the biological clock can be shifted by giving it a kind of a push b

ut with light the kind of fast resetting of the biological clock that charles seisler discovered works like this on the first day a dose of strong light literally stops the clock and with a clock then in the kind of limbo it can be reset to any time by giving it a second dose a strong push of light so how can we use this information for practical problems like jet lag sizeless studies were done with young males the results may be different for older people for females and for short flights as op

posed to long flights but at least there's the possibility that in the future you may be able to get a different kind of frequent flyer card one that tells you the best time to use light to reset your biological clock here's how it might work let's say you fly from los angeles to tokyo so you need to set your clock back seven hours according to this graph known as a phase response curve around 3 am los angeles time is when you should be exposed to strong light another example london is eight hou

rs ahead of los angeles so light exposure should be around 6 30 a.m los angeles time [Music] while scientists sort out the practical details of lighting up our lives another cure for jetlag may be on the horizon early tests with the hormone melatonin are promising mit neuropharmacologist richard wordman the number of investigators working all over the world have published evidence that if they give melatonin to people at two o'clock in the morning coinciding with two o'clock in the morning in th

e place where they're going and do this for three or four days in advance the people seem to have an easier time when they arrive with with less jet lag we're not yet at the point where i can recommend this to your to your viewers melatonin is not an approved drug this is simply a a research study that's been done in a number of labs around the world but if it's true it would be quite nice you can think of melatonin as a kind of bottled light both melatonin and light can reset the biological clo

ck melatonin is manufactured in the pineal gland levels of the hormone vary on a strict daily cycle it's a very reliable rhythm the rhythm and blood melatonin levels probably the most reliable reproducible rhythm in the body and we think that this rhythm constitutes a signal a time signal to other parts of the body it tells the brain when it's night and when it's daytime and as such it can lock in place other brain rhythms behavioral rhythms one of these rhythms is the most obvious of our daily

cycles sleeping and waking laboratory studies have found that melatonin makes people drowsy so there is obviously some sort of a link between our circadian rhythms melatonin and the pineal gland the function of the pineal was a mystery until about 30 years ago most scientists thought it was a kind of vestigial part of our anatomy a sort of appendix but in the brain some mystics called it the third eye and suggested it was the pathway to enlightenment which was partly right and partly for the bir

ds literally you see most birds and fish reptiles and amphibians do have a pineal which is directly sensitive to light passing through their skulls during daylight the melatonin production lines shut down at night they start up again so you really could say that in these animals at least the pineal is the third eye now move on to mammals including ours and the story changes evolutionists produced a kind of division of labor the pineal is still doing its old job of sending time of day signals thr

ough melatonin but it can no longer sense light and dark directly because of these thick skulls of ours so that task has been taken over by the retinas in the eyes which send nerve signals to the brain putting it all together information about light and dark travels straight from the eyes to the scn which then sends nerve signals to the pineal finally the pineal translates those nerve signals into chemical signals it broadcasts a rough time of day message to the rest of the body in the hormonal

code of melatonin these members of the young musicians foundation orchestra conducted by lalo shifrin are developing their instrumental skills their ability to play in harmony to keep time to follow cues [Music] in the circadian symphony the various players are like seasoned professionals finely tuned by the pressures of natural selection in a sense each dawn is another command performance fortunately we don't have to spend too much time in rehearsal our timing comes to us almost literally with

our mother's milk as well as playing a key role in our daily rhythms there's now good evidence that melatonin is largely responsible for the initial setting of the biological clock early in development and if you think about it it makes sense for newborn animals to hit the ground with their biological clocks already running because if you want to increase your chances of survival it pays to be in sync with the environment from day one [Music] so how is the clock preset does the fetus see light a

nd dark through the womb or does it pick up time signals from the mother in the case of rats massachusetts general hospital neurobiologist steven report found the answer we could actually place the fetus in a situation where it had to choose between the timing of the light dark cycle in the external environment and the timing of mom's biological clock because they were out of sync with each other and when we did those sorts of experiments what we found is that the fetus always is in time with th

e mother particularly when it comes to how mother coordinates the fetal biological clock we now know based on our human studies and also studies in experimental animals that particular receptors binding sites for melatonin are also present in the biological clock of the fetus so the mother's hormone rhythm of melatonin may in fact be one way in which the fetus receives time of day information in fact the cells of a human embryo's clock are already in place three months before birth and there's e

very reason to think that by the time of birth the infant thanks to signals from the mother will already be in the swing of things just as the oscillation of this foucault pendulum at the griffith observatory is evidence of the rotation of the earth so is the ticking of the biological clock if scientists from another planet had an earthling for research they'd be able to tell a great deal about the planet we evolved on by simply reading our rhythms all the rhythms of the timers we have made just

stop for a moment and look at your wristwatch because what you've got there especially if it's the old-fashioned kind with a circular dial and a big hand and a little hand instead of a row of numbers what you've got there is a portable model of the celestial clockwork that astronomers study using telescopes as we've seen we also have here in our brains a kind of stripped down rough and ready biochemical version of the same information cued by light and dark which is fine if your goal is simply

to keep step with nature but we've always wanted more control of the time of our lives so we started to organize time we invented devices that allowed us to keep precise track of the time to chronicle the past to calibrate the present and to plan for the future we made calendars like this aztec calendar stone which is both a representation of their empire's place in space and time and a way of keeping track of rituals and religious events or like the book of hours a kind of 15th century bestsell

er that chronicled the times of prayer and the passage of the seasons but finding a system that perfectly matched the celestial clockwork wasn't so easy the egyptians started out with a lunar calendar that was recalibrated by the appearance of the star sirius in the pre-dawn sky it's a perfectly good lunar calendar every couple of years or so they brought it back into step with the seasons in the nile and they were perfectly happy with it except they had an empire to run and then they developed

a civil solar calendar a calendar based on the 365 or so days of the year it didn't have anything to do with the moon it was completely independent of the moon and they ran two calendars one for each purpose and they eventually got around to making a third calendar and the third calendar was kind of a combination of those they sort of liked that old lunar calendar that kept the festivals and the sacred moments in touch with the moon but they couldn't always do that with the solar calendar so the

y devised a third calendar that would make the two match every time they wanted it to happen and with three calendars running that apparently was enough to keep them happy [Applause] we need calendars because unlike other animals we lack strong annual rhythms although those of us who suffer from seasonal affective disorder do feel distinctly better after a winter of discontent judith wortman is an obesity researcher at mit we were doing a study on seasonal affective disorder at mit and when we a

dvertised this study asking for people who felt depressed in the fall and winter and over ate and gained weight we got a phone call from a distraught woman who had moved to massachusetts from san diego where she'd spent almost all her adult life told us that she didn't understand why every fall and winter since she'd moved to massachusetts she felt like sleeping all day and when she wasn't sleeping all she was doing was eating she'd gained 40 pounds from november through january and she thought

she was undergoing some nervous breakdown judith wordman and her husband richard had already studied this kind of behavior in clinical trials they'd taken groups of overweight individuals and monitored their eating habits the volunteers chose meals from foods that have been rated for protein fat calorie and carbohydrate content in between they had access to vending machines like this although it was linked to a computer to keep track of the snacks now the odd thing was that at regular meal times

the volunteers ate regular meals about 1900 calories nice balance of protein and carbohydrate nothing really very fattening what got them was the snacks because they virtually ignored protein and went straight for the carbohydrates and many of these carbohydrate binges had symptoms that were very similar to those you associate with seasonal affective disorder or sad these people tend to become depressed when there's little light outside that is november or december and they get better spontaneo

usly in the springtime in march or april and when they are depressed their symptoms are often very different from those of people with typical depression for instance people with typical depression will tend to have too little sleep they'll awaken spontaneously at four o'clock in the morning be unable to go back to sleep people with sads may be sleeping nine or ten hours per day and they still feel exhausted but one other major difference between these groups is how they eat people with depressi

on may lose weight they lose their appetite people with seasonal affective disorder tend to gain weight every winter and they gain weight because they are specifically eating large amounts of carbohydrates they are picking out on carbohydrates if you will as for the woman from san diego the prognosis was good we helped her she came into our study she happened to participate in the study in which we used a drug that increases serotonin availability to the brain and her depressed mood went away sh

e stopped sleeping all day she stopped gaining weight and actually lost weight serotonin is a neurotransmitter that's released from certain brain neurons and we know that it's critically important in appetite in mood and sleep and pain sensitivity and a lot of functions and it just may be the case that the reason these people are consuming carbohydrates is because somehow they intuitively know that their depression gets better when they eat carbohydrates the depression may get better because the

carbohydrates are increasing brain serotonin so boosting serotonin is one way to beat the winter blues another is light a dose on winter mornings is routine therapy for sad patients which suggests that melatonin is somehow involved but how are these two treatments connected it's possible for instance that the hormone melatonin might act on behavior by affecting brain nerve cells brain neurons that use serotonin it's possible but nobody has shown that yet a lot of people i'm sure are looking to

see whether or not melatonin acts on serotonin would be nice to tie these things together but meanwhile i guess we'll just have to be grateful that we have two strategies that work that help patients the heart beats the blood surges cells divide hormones ebb and flow these are rhythms that have been drummed into us for eons we are all partners in this dance to the music of time the biological anthem of earth [Music] it is ironic that our ability to savor the elegance and power of our inner caden

ces is the result of missing a beat of finding ourselves out of sync are the only animal with this problem and the only animal capable of finding a solution in fact what we are being forced to learn may well improve our lives in medical research for example there is growing evidence that a drug's effects can depend on body time when you take a drug may be just as important as the drug itself at the city of hope medical center in duate california researchers are trying to assess the impact of the

timing of drug therapy on cancer patients the key idea is that some tumor cells divide at a different time of day than normal cells and the drug being tested attacks cells only when they're dividing cell biologist bob clevitz that gives us a real opportunity to treat with high doses of very division specific drugs and to do it repeatedly every day um only at the time when the tumor cell is replicating and for patients like that we can be quite optimistic this flow cytometer uses a laser to prob

e up to 15 000 cells a second clevitz and his co-workers can determine which stage each cell is at in his division cycle a population of cells at any given moment can be visualized like this cells that are in the process of dividing can in a sense be clocked from their trace on the graph by looking at the information in different ways clevitz hopes to find a distinctive time signature for cancer cells clevitz's colleague ron shimko has been working on a computer model that demonstrates the kind

of drug therapy that would need to be developed to combat cancer cells that don't divide like clockwork now suppose we had a drug which could affect the cycling the timing of those cancer cells all in exactly the same way we could administer that drug all these cells would behave in a predictable way and most likely they would become partly synchronized here's how a future drug might work each disk represents a group of tumor cells let's suppose they all divide at different times we need a drug

that could somehow herd them together with the first treatment the cell populations become partially synchronized successive treatments then merge them together so that they can eventually all be attacked at the same time during the crucial division phase moving inside the cell we may eventually understand our rhythms at the level of dna scientists have recently identified a tiny fragment of the dna of the fruit fly drosophila which forms part of the blueprint of its daily clock that same fragme

nt appears in a very different organism a fungus a clue to scientists that similar clock genes may be part of our timing machinery as well opening doors at the genetic level or turning the model world of ron shimko's computer into reality may take years in the meantime the standoff between technology and biology continues of course it is a comparatively recent problem jet lag is a phenomenon of only the past 40 years and our understanding of the scn and the pineal came even later in boston massa

chusetts the institute for circadian physiology's human alertness research center is designed to be a model environment for probing and solving circadian disorders [Music] chronobiology has intrigued director martin moore eid since his days as a medical intern working 36-hour shifts and having experiences like this coming into the awards um in the morning and having nurses question you about prescriptions you had ordered over the phone they called you up about in the middle of the night and you

couldn't recollect what exactly you prescribed or why you prescribed it so it made a point to me at that time that there was something pretty fundamental about this loss of alertness that happens to us this intense sleepiness that happens to us this difficulty of staying awake it's not something that will power on well the best motivation in the world will save you from it's really a fundamental biological facet imagine it's four in the morning a time when our distant ancestors might have been c

urled up in a cave somewhere keeping out of trouble and now look what we're doing sitting at the control panel of a nuclear power plant fighting sleep trying to stay alert in fact this isn't a real power plant it's a simulator at moore eads institute volunteers work various shift patterns here while their alertness levels are constantly monitored research like this may help prevent future disasters taking place especially during the dangerous graveyard shift between midnight and 6 a.m when human

alertness is at a low ebb according to moore eid we have been lulled into a false sense of security by our own inventions we've got these computerized control panels these computerized devices these autopilots and planes these highly automated industrial plants and what we do is we've made them really reliable now what do we do we take a human operator whether it be a pilot in a plane or a nuclear power plant operator or an or a refinery control room operator and we put this person in front of

this device and we tell that person your job is to watch the machine your job is to keep check on the machine but which is the unreliable element it isn't the machine it's the human [Music] if you've never worked a shifting schedule imagine this you work one week in new york the next week in paris and the next in tokyo since your biological clock is in a sense an antique it's no surprise it has a hard time keeping pace with newfangled schedules the circadian timer is so finely tuned that even a

one-hour shift can be unsettling studies show that during the week following the shift to or from daylight savings traffic accidents increase and with the bigger time shifts of many work schedules serious health problems begin to show up shift workers have two to three times as many ulcers as workers on a fixed schedule and three times the risk of heart disease though shift work research is still at an early stage scientists have already discovered one important principle if you must work a rota

ting schedule it's easier to move to a later rather than an earlier shift why well that's one of the key findings of the cave experiments that first made accurate measurements of the internal human clock [Music] those studies including this recent one recorded by italian filmmakers found that isolated from all time cues the human clock counts out roughly a 25-hour day light in the morning re-corrects that disparity between the 25-hour pacemaker the 25-hour natural rhythm and the 24-hour day it h

appens so smoothly and so often automatically we're totally unaware of it because shift workers often don't get a resetting dose of light their clocks run late a schedule that shifts from morning to afternoon to night catches the internal clock's natural drift to later hours something similar happens to people who party when weekend arrives on friday night they stay up a little later and they sleep in on saturday morning in order to try to they're thinking that they're doing themselves a favor b

y catching up as it were on on missed sleep and then on saturday night they stay up again later sleeping in on sunday morning but then they have to pay the piper on sunday night because when they try to go to bed at their regular bedtime on sunday night that may be the equivalent of six or seven in the evening biological time because they've let their internal clock drift to later hours and then when it's time to wake up at uh six o'clock in the morning on monday that may be the equivalent to th

ree o'clock in the morning biological time and that's when those extra cups of coffee are used to try to overcome the symptoms of being out of sync with the environment [Music] it's worth remembering that chronobiology is a science in its infancy our knowledge of our rhythms is the product of only about 30 years of research a few ticks of the clock in evolutionary terms with each increase in our understanding we're moving closer to a time when we may be able to control the beat to march to our o

wn drummer we are needing humans to watch a 24-hour industry that we're driven to because of economic concerns because of technology because of automation because of telecommunications and we're not smart enough in terms of that automation to have the lights out factory or the pilotless plane we've got a 20-year problem here because in 20-25 years we will have those totally automated plants and facilities we won't require people to work shifts at night we won't require humans to make judgments a

nd be at risk of errors but we need them now if more aid is right and our inventions someday free us from work for which we're poorly endowed might we return to the gentler rhythms of bygone days from our vantage point of the late 20th century it's easy to feel nostalgic about a time when people seemed more attuned to nature's cycles but think again here's an animal which lives in harmony with the tidal rhythms but harmony this perfect is also a kind of tyranny for the crab the tides are both pl

ayground and prison technology has given us the freedom to step out of sync with nature's rhythms and step out we have creating a new kind of dissonance as our biological and technological clocks do battle [Music] but harmony can be restored with the help of the same technology that allowed us to discover our rhythms in the first place we may yet come full circle and make a mandala of our own [Music] perhaps the most appealing thing about this kala chakra mandala this wheel of time is that in on

e symbolic representation you have past present future gods planets and stars sun and moon body and soul wisdom and bliss it's a great package harmony resonance a sense of oneness with the universe all those things that we perhaps fear we've lost in a high-speed high-tech society and yet as we've seen during the past 25 years we've learned more about our rhythms than during the rest of our time on earth information that's helping us to fight disease overcome depression combat fatigue and jet lag

perhaps we're finally beginning to listen to those rhythms perhaps we're really beginning to understand what makes us tick [Music] do [Music] [Applause] [Music] [Applause] [Music] [Applause] [Music] [Applause] [Music] [Applause] next from london and new york a new kpbs series on the stars of pop music stay tuned for wired [Music] [Applause] [Music] major funding for this program is provided by the lk whittier foundation [Music]