Tired workforces

economist

Tired workforces

April 21st, 2009

Tired workforces

This house believes that we are not getting

enough sleep.

Economist Debates


Economist Debates: Tired workforces

About

Economist Debates adapt the Oxford style of debating to an

online forum. The format was made famous by the 186-yearold

Oxford Union and has been practised by heads of state,

prominent intellectuals and galvanising figures from across

the cultural spectrum. It revolves around an assertion that is

defended on one side (the “proposition”) and assailed on

another (the “opposition”) in a contest hosted and overseen

by a moderator. Each side has three chances to persuade

readers: opening, rebuttal and closing.

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Economist Debates: Tired workforces

Table of contents

The motion.................................................................. 5

Opening statements .................................................... 6

The moderator ............................................................ 6

The moderator’s opening statement............................... 7

Defending the motion .................................................. 9

The proposer’s opening statement ............................... 10

Against the motion .................................................... 14

The opposition’s opening statement............................. 15

Featured guest, Dr Gregg D. Jacobs............................. 19

Rebuttal statements.................................................. 24

The moderator’s rebuttal statement............................. 24

The proposer’s rebuttal statement ............................... 27

The opposition’s rebuttal statement ............................. 31

Featured guest, Dr Thomas J. Balkin............................ 35

Featured guest, Professor Jim Horne............................ 40

Closing statements.................................................... 45

The moderator’s closing statement .............................. 45

The proposer’s closing statement ................................ 48

The opposition’s closing statement .............................. 53

Winner announcement .............................................. 57

Winner announcement ............................................... 57

Background reading .................................................. 60

The supporter: Phillips .............................................. 61

Interview with Dr David White, Chief Medical Officer, Philips

Home Healthcare Solutions ......................................... 61

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Economist Debates: Tired workforces

April 21 st – May 8 th 2009

The motion

“This house believes that we are not getting enough

sleep.”

Unemployment, repossession and a falling stock market.

There is nothing like a recession to keep people awake at

night. Add economic anxiety to the normal stress of work and

family, and you would think that the world must be full of

insomniacs. Are we getting enough sleep, and how much

sleep is enough? In these troubled times, should people be

sleeping less, so they can accomplish more?

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Economist Debates: Tired workforces

Opening statements

Opening statements were originally published on April 21st

2009. They can be viewed online at

http://www.economist.com/debate/days/view/301

The moderator

Alison Goddard

Science Correspondent, The Economist

Alison Goddard reports on all aspects science for The

Economist and is particularly interested in the mysteries of

physics, including dark energy, dark matter and the fabric of

reality. She is the author of a forthcoming biography of Luc

Hoffmann, a green philanthropist and one of the founders of

the World Wide Fund for Nature. Alison has two degrees, one

in physics and the other in politics, philosophy and history,

and a masters degree in science communication. As the

mother of two young children, she has had little recent

experience of sleep.

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Economist Debates: Tired workforces

The moderator’s opening statement

April 21 st 2009

People generally spend about a third of their lives asleep. A

century ago, they had little choice. Artificial light was dim

and little could be accomplished by it. So people went to bed

soon after dark and rose with the lark. The invention of the

electric light bulb changed all this. Now it is perfectly possible

to get on with useful—and, perhaps more entertainingly,

frivolous—pursuits during the hours of darkness. The advice

handed down from grandmother, to get at least eight hours

of sleep a night, with an hour before midnight being worth

two after, goes unheeded. What are the consequences of

ignoring her counsel?

Staying awake for longer obviously enables people to achieve

more. As students around the globe will attest, revising for

examinations into the early hours boosts the grades attained.

Indeed, many students are reported to take stimulants such

as Ritalin and Modafinil in order to stay alert for longer. But

at some stage, sleep becomes vital. It is not only essential to

restore alertness; sleep is also critical for learning as well as

many other measures of well-being, both physical and

mental.

Involuntary insomnia, perhaps brought on by economic

anxiety, achieves little. Spending several wakeful hours

staring in frustration at a darkened ceiling is no one's idea of

fun. People who suffer from insomnia tend not only to be

tired and perform less well in the workplace but also to be

depressed. Some studies show that people who take sleeping

pills are sicker than those who do not.

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Economist Debates: Tired workforces

Are we getting enough sleep? The question has bothered

many distinguished thinkers for decades. We are privileged

to have two great authorities to discuss the issue. Robert

Stickgold of the Harvard Medical School argues that people

who do not get enough shut-eye become "fat, sick and

stupid" as a result. Dan Kripke of the University of California,

San Diego, reckons that too much sleep has similar

consequences. Let the debate commence.

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Economist Debates: Tired workforces

Defending the motion

Dr Robert Stickgold

Associate professor of psychiatry at Beth Israel Deaconess

Medical Center and Harvard Medical School

Robert Stickgold is an associate professor of psychiatry at

Beth Israel Deaconess Medical Center and Harvard Medical

School. He received his BA from Harvard University and his

PhD from the University of Wisconsin, both in biochemistry.

He has published two science fiction novels and over 100

scientific publications, including papers in Science, Nature

and Nature Neuroscience. His current work looks at the

nature and function of sleep and dreams from a cognitive

neuroscience perspective, with an emphasis on the role of

sleep and dreams in memory consolidation and integration.

In addition to studying the normal functioning of sleep, he is

currently investigating alterations in sleep-dependent

memory consolidation in schizophrenics and patients with

posttraumatic stress disorder. His work is funded by U.S.

National Institute of Mental Health.

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Economist Debates: Tired workforces

The proposer’s opening statement

April 21 st 2009

Are we getting enough sleep? While the answer to this

question obviously depends on who "we" are, and what

"enough" means, the bulk of the scientific evidence supports

a resounding "No". We need more sleep.

Let me summarise what I am going to tell you: you are

probably not getting enough sleep, and you know it. If

sleepiness doesn't kill you on the highways, the

consequences of inadequate sleep are going to dramatically

increase the likelihood that you end up fat, sick and stupid.

Let us look at these claims one at a time.

First, we know that we are not getting enough sleep. Of

among 100,000 randomly selected individuals enrolled in a

telephone survey, a quarter reported that they "did not get

enough rest or sleep" on at least half of the previous 30

nights. Of those 18-34 years of age, the number was even

higher, at 33%, and 10% of all respondents reported never

getting enough. So we know from our own experience that

we are not getting enough sleep. Caffeine consumption is

another measure of our sleepiness. After oil, coffee is the

largest traded commodity on the world markets in terms of

total dollar amount. Americans alone drink over 300 million

cups of coffee a day, and that number ignores caffeinated

soft drinks. We clearly know that we are not getting enough

sleep and are desperately self-medicating ourselves in the

hope of waking up.

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Economist Debates: Tired workforces

Our daytime sleepiness is killing us on the road. Recent

analyses of vehicular deaths suggest that sleepiness is as big

a culprit as alcohol. Shifting to daylight savings time in the

spring, when Americans lose just one hour of sleep over a

weekend, leads to a 9% increase in automobile accidents the

following day. This is not due to just a few short sleepers.

37% of Americans admit having fallen asleep at the wheel at

least once, and 6% report having done so in the last six

months. So despite our use of caffeine to help keep us

awake, our sleepiness is killing us on the highways. (Forgive

me if most of the data I present is for Americans, but most

studies have been carried out in the United States.)

There is a common misperception that all that sleep does is

cure sleepiness. But sleep is a time when the body and brain

actively prepare for the next day. Every year, more evidence

comes out about the importance of adequate sleep in

maintaining our health and sanity. Just some of these studies

should prove the point.

For a start, sleep is critical for the effective operation of the

immune system. So if you do not get enough sleep, you will

probably get sick more often. In one study, subjects who

stayed up all night after getting immunised against hepatitis

ended up producing only half as much antibody against the

virus as those who slept normally. In another study,

participants who reported sleeping, on average, less than

seven hours a night were three times more likely to get sick,

when exposed to a cold virus, than those who averaged eight

hours or more.

Adequate sleep is also critical for maintaining normal glucose

metabolism and for preventing both obesity and type II

diabetes. Our feelings of hunger and satiety are controlled by

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Economist Debates: Tired workforces

two opposing hormones, ghrelin and leptin; high ghrelin

levels and low leptin levels make us feel hungry. When

subjects were restricted to five hours of sleep a night for a

week, their leptin levels dropped by 17% and ghrelin

increased 28%, despite food intake being rigorously

maintained at a constant level. With unrestrained eating,

these changes would normally lead to the consumption of an

extra 1,000 Kcal of food, half of your normal daily intake.

Indeed, when subjects in another study were allowed to eat

as much as they wanted, their desire for high carbohydrate

(read "junk") food went up 32%.

These same studies showed that with inadequate sleep,

glucose regulation goes awry. Subjects whose sleep had

been restricted to five hours a night showed signs that

normally presage the onset of diabetes after less than a

week of restricted sleep. But these are experimental

subjects. Wouldn't people who normally sleep less get used

to it? Don't their bodies adjust? Apparently not. Subjects who

normally sleep no more than 6.5 hours a night show 40%

higher insulin sensitivity than those sleeping eight hours,

levels that reflect a significant risk of diabetes.

But inadequate sleep also impairs mental functioning. As the

most basic level, inadequate sleep leads to poor attention.

Limiting sleep to just seven hours in bed for a week leads to

a dramatic decrease in the ability of individuals to maintain

sustained attention. On a simple test of attention, a quarter

of subjects restricted to six hours per day in bed fell asleep

during testing, taking over 30 seconds to respond to the

appearance of an obvious signal on their computer screen.

Interestingly, although subjects perceived their performance

as stabilising after three days, it actually continued to

deteriorate across the entire week of sleep restriction.

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Economist Debates: Tired workforces

Attention is not the only cognitive impairment produced by

inadequate sleep. Learning and memory are also affected.

Memories formed and skills learned during the day are

stabilised, enhanced and integrated with other memories and

skills during sleep the following night. For example, with a

visual skill learning task, individuals actually improve over a

night of sleep, performing better the next day. But this

improvement is in proportion to how much sleep they obtain

in excess of six hours. Twice as much improvement was seen

with eight hours of sleep than with seven hours, and no

improvement was seen with six or less. More recent studies

suggest that REM sleep, which is most prominent at the very

end of the night, is critical for integrating newly learned

information into our larger networks of pre-existing

memories, helping us make meaning out of the events of the

preceding day. Getting less than eight hours may prevent

this crucial work from being done.

So it is most likely literally true that if you are getting less

than the eight hours of sleep your body is asking for, both

your body and your mind will pay the price.

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Economist Debates: Tired workforces

Against the motion

Dr Daniel Kripke

Co-director of Sleep Research at the Scripps Clinic Sleep

Center, La Jolla, CA

Daniel Kripke is co-director of Sleep Research at the Scripps

Clinic Sleep Center, La Jolla, CA. He is a practicing

psychiatrist treating patients with sleep disorders. He is also

Professor Emeritus in the Department of Psychiatry at the

University of California, San Diego.

For over 30 years, he has been studying health and survival

related to sleep duration, insomnia and sleeping pills. His 230

scientific articles cover more than 2.2m research volunteers

who have been followed prospectively for six years or more.

Recent interests include bright light treatment of depression

and the genetics of body clocks. His two non-profit web sites

are www.DarkSideOfSleepingPills.com and

www.BrightenYourLife.info, sources of information for people

with sleep disorders, depression and body clock disturbances.

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Economist Debates: Tired workforces

The opposition’s opening statement

April 21 st 2009

Most of us get enough sleep. A fair percentage even spend

too long in bed, but there is wide diversity among us. For

most people, there is no persuasive evidence that spending

more time in bed would be good for them or for the folks

around them.

These days, adults in the United States and much of Europe

say they sleep an average of 6.5-7.5 hours a night. In study

after study, people who sleep 6.5-7.4 hours live the longest,

so most people are getting enough sleep. People who report

sleeping five or six hours live almost as long. In fact, people

who sleep five or six hours may live a bit longer than people

who sleep eight hours. People who sleep five or six hours live

considerably longer than the person who sleeps nine hours or

more. With the best survival among those with rather short

sleep durations, it would be hard to prove that increasing

sleep time would be good for most people.

By the majority of measures, those with average or short

sleep seem healthier also. Recent results from the Hordaland

study in Norway showed that working people who reported

sleeping less than 6.5 hours a night did not suffer any

significant increase in disability. Those who reported more

than 8.5 hours were more than twice as likely to become

disabled as those who slept 6.5-7.5 hours. Those who slept

7.5-8.5 hours were slightly more likely to become disabled

(not significant). The suggestion from this study was that, if

anything, spending more time in bed might tend to increase

disability.

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Economist Debates: Tired workforces

To give more examples, the six-hour sleeper is less likely to

develop diabetes than the nine-hour sleeper. The six-hour

sleeper is less likely to have a stroke than the long sleeper.

Incidentally, I have not been able to find evidence that

people who sleep more than average earn more money or do

more to help other people. Quite the opposite.

You might think that more sleep would be good for mood,

but those who sleep nine or ten hours tend to be very

depressed. A counter-intuitive surprise is that sleep

deprivation actually improves mood, at least in the short run.

Insomnia is not mainly a problem of short sleep: those with

more than average sleep frequently report insomnia.

Moreover, the false belief that people generally need eight

hours of sleep is one of the common causes of insomnia.

Spending less time in bed is an important solution for many

with insomnia.

Nobody seems to know exactly where the idea that we

should sleep eight hours came from. I guess it was just

passed down from somebody's grandmother.

It turns out that many of the chief proponents of more sleep

are being paid by the sleeping-pill industry. The industry

thinks that campaigns for more sleep increase sleeping-pill

sales. Some people imagine that sleeping pills help them

cope on the following day, but the majority of objective

studies show that sleeping pills have no benefit for next-day

performance or even make behaviour worse. A recent 20year

study from Sweden showed that men who took sleeping

pills had even more early deaths and more cancer than those

who smoked cigarettes. There have been 16 other studies

showing excess mortality among sleeping-pill users. Perhaps

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Economist Debates: Tired workforces

epidemiologic studies do not necessarily prove that sleeping

pills cause mortality, but the pharmaceutical industry has

done randomising controlled trials showing that sleeping pills

increase depression and infection, and probably increase the

likelihood of cancer.

We should be worried that many disasters are caused by

mistakes made in the early hours of the morning: the

Chernobyl and Three-Mile-Island nuclear melt-downs, the

Bhopal disaster, Exxon Valdez and so forth. Work shifts

between midnight and 6 am produce increased numbers of

minor and serious errors. Night work does curtail sleep,

which is part of the problem, but the main difficulty is that

night workers try to function when the body clock is lowering

alertness and the metabolism. The circadian rhythm problem

in night work is more important than the element of sleep

loss, so these causes should be distinguished. Moreover, for

many shift workers, the issue is that they are unable to sleep

enough during the day, and too little is known about how

their sleep disturbances could be managed. As modern

economies increase the percentage of night workers, much

more research is needed to find solutions for the problems of

shift workers.

Similarly, after midnight vehicle accident rates are very high.

Here again the impairment may come more from the

downside of circadian rhythms than from any acute sleep

loss. Many road accidents are caused by young lads who

have been abusing alcohol or other substances as well as

staying up much too late. I have seen no convincing evidence

that the person who regularly averages six hours of sleep a

night has more accidents than the person who sleeps eight

hours. There is some evidence that nine-hour sleepers are a

danger on the road.

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Economist Debates: Tired workforces

Of course, there are people in particular situations who

should get more sleep. Research shows that doctors and

nurses make more mistakes when their work hours are too

long to allow enough sleep. I would prefer that their

schedules provided adequate sleep.

Years ago, a small Navy submarine sank in San Diego Bay,

possibly due to a mistake by a sailor whose commanders had

allowed him only 4-5 hours' sleep for weeks. His commander

testified at the court-martial that such sleep schedules were

routine on nuclear submarines. I would prefer that the

fellows with their fat fingers on the nuclear red buttons were

getting more sleep. Stressed doctors, nurses and

submariners are some of the exceptions to the general point

that most people sleep enough.

For most people, this debate's proposition that we do not get

enough sleep is misguided.

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Economist Debates: Tired workforces

Featured guest

Dr Gregg D. Jacobs

Insomnia specialist at the Sleep Disorders Center at the

University of Massachusetts Medical School

Gregg D. Jacobs is an insomnia specialist at the Sleep

Disorders Center at the University of Massachusetts Medical

School. He spent 20 years treating and researching insomnia

at Harvard Medical School, where his research was funded by

the National Institutes of Health. His work on insomnia has

been featured extensively in the media, including the New

York Times, Wall Street Journal, Washington Post, Good

Morning America, the Today Show, Time magazine, Forbes

and the Boston Globe. He has been described by the Wall

Street Journal as a "pioneer in the use of cognitivebehavioural

therapy for insomnia".

He is the founder of www.cbtforinsomnia.com where his

cognitive behavioural therapy program for insomnia is

available online.

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Economist Debates: Tired workforces

Featured guest, Dr Gregg D.

Jacobs

April 22 nd 2009

I oppose the motion that we are not getting enough sleep. A

minority of adults are not getting enough sleep, including the

10-15% that report chronic insomnia and individuals who

restrict sleep due to occupational and social demands and

experience excessive daytime sleepiness as a result.

However, the generalisation that the population as a whole is

not getting enough sleep, and the popular recommendation

that we should sleep at least eight hours per night, are not

supported by a large and diverse body of data.

Annual "Sleep in America" survey polls by the National Sleep

Foundation (NSF) consistently indicate that the majority of

adults are getting enough sleep. These NSF polls find that

adults average about seven hours of sleep; that the majority

sleeps seven or more hours and that the majority feels

rested and energetic. Further, only a small minority reports

daytime sleepiness. For example, 72% report that sleepiness

rarely or never interferes with daily activities, only 7% report

feeling drowsy on a daily basis, and the majority nap once a

month or less frequently. In short, the current adult average

sleep duration of seven hours is not associated with any

consistent indicators of daytime sleepiness or sleep debt.

Massive epidemiologic evidence from at least 20 studies also

suggests that the current adult average sleep duration of

seven hours is sufficient. This epidemiologic evidence

consistently demonstrates a U-shaped curve involving sleep

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Economist Debates: Tired workforces

duration and mortality, with the lowest mortality at seven

hours of sleep. In most of these studies, the risks associated

with eight or more hours of sleep have been at least as great

as less than seven hours of sleep, and many of these studies

found that long sleep is associated with greater mortality

than short sleep. Further, the significance of short sleep has

generally decreased or disappeared after controlling for

factors known to be associated with mortality (smoking,

alcohol use, physical inactivity). In contrast, sleeping eight or

more hours is associated with elevated mortality risk even

after controlling for smoking and similar factors. In short,

epidemiologic data suggest that sleeping more than the

current adult average sleep duration of seven hours may be

a health risk.

Consistent with the preceding survey and epidemiological

data, there is no experimental evidence that the current

adult average sleep duration of seven hours is associated

with impaired neurobehavioural functioning. A few small

laboratory studies have suggested that, if allowed to extend

time in bed, young normal sleepers without complaints of

daytime sleepiness who report sleeping 7.0-7.5 hours can

extend their night-time sleep by about an hour to 8.0-8.5

hours if given the opportunity. However, these laboratory

findings may not readily generalise to daily life since they

involve young sleepers in laboratory conditions of low arousal

and boredom, and recent studies suggest that older sleepers

have a lower homeostatic sleep drive and sleep need

compared with young adults. Furthermore, extending nighttime

sleep has small or non-significant effects on

neurobehavioural functioning, subjective alertness and

objective alertness, and naps or caffeine have greater

benefits. Adults may have a low level of daytime sleepiness

that is normal and tolerable, particularly in younger adults

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Economist Debates: Tired workforces

and in the afternoon, due to a circadian propensity for an

afternoon nap (that most of us skip) rather than insufficient

night-time sleep or a sleep debt. However, naps or caffeine

are more effective and practical than extended night-time

sleep in countering this mild sleepiness, and the NSF survey

polls clearly suggest that any mild daytime sleepiness is not

noticed consistently, does not interfere with daytime

functioning and does not necessitate naps consistently.

Indeed, the only time this mild daytime sleepiness may even

be noticed is when lying down in the afternoon and relaxing.

Many people simply cannot extend night-time sleep because

they are already allowing sufficient time for sleep, are getting

the sleep they need or are short sleepers. Moreover,

recommendations to get more sleep by extending time in bed

can cause insomnia and reduced sleep efficiency, increased

sleep fragmentation and impaired glucose tolerance. In

addition, there is no evidence that sleeping pills (which

extend sleep) reduce mortality or improve health outcomes.

In fact, they increase mortality risk, as documented in 15

epidemiologic studies.

Finally, even the limited experimental data suggesting that

six hours of sleep is associated with impaired daytime

functioning may not generalise to the adult heterogeneous

population for numerous reasons.

These data typically involve young, eight-hour sleepers

who are restricted to six hours of sleep. Most adults do

not restrict sleep by several hours per night and most

adults sleep more than six hours per night.

There are significant individual differences in response to

sleep loss, even with as little as four hours of sleep.

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Economist Debates: Tired workforces

People who sleep six hours per night are just as healthy

on health-related quality of well-being measures as those

who sleep eight.

Older and shorter sleepers are less sensitive to the effects

of sleep loss, and a recent study found that older people

appear to need less sleep than younger people do.

Most studies on the deleterious effects of sleep loss in the

laboratory typically involve far more severe sleep loss

than the more modest sleep loss experienced in daily life,

which is usually accompanied intermittent recovery sleep.

In summary, it is preliminary to say that we are not getting

enough sleep or that we need eight hours of sleep. Instead of

devoting more time to sleep, the data suggest that we would

be better served by taking short afternoon naps and devoting

time to more vital health-enhancing activities, such as

exercise. The recommendation that we need more sleep has

become a double-edged sword that has raised awareness of

the importance of sleep on the one hand, while worrying

more people into insomnia and sleeping pills—and their

potentially serious side-effects—on the other.

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Rebuttal statements

Rebuttal statements were originally published on April 24 th

2009. They can be viewed online at

http://www.economist.com/debate/days/view/308

The moderator

Alison Goddard

Science Correspondent, The Economist

The moderator’s rebuttal statement

April 24th 2009

In their rebuttals, both sides raise some interesting points.

Robert Stickgold highlights the discrepancy between what

people say and what people do. Those who say they make do

with less sleep may, in fact, be sleeping for longer than they

confess to. This argument works both ways, though. Those

who say they would like to sleep for longer do not necessarily

avail themselves of an early bedtime when it is presented.

Neither is self-reported sleep time a reliable measure, Dr

Stickgold points out. People can be pretty hopeless at

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Economist Debates: Tired workforces

estimating how long they have been staring at the ceiling

before they finally fall asleep.

In a similar vein, there is a difference between saying you do

not get enough sleep and it actually being demonstrated that

you are sleep-deprived. Daniel Kripke points out that people

like to eat tasty food and, if offered a second helping, will

want to take it even though it is unhealthy. People are

greedy for sleep, he reckons, and that greed is not

necessarily good.

Gregg Jacobs, an insomnia specialist, says that the average

duration of sleep is not eight hours but seven. Moreover, he

highlights research which shows that sleeping fewer hours or

more hours than this is bad for your health, which, at the

extremes, supports both the positions of Dr Stickgold and Dr

Kripke.

There have been many interesting comments from the floor.

These have examined not only how individuals seem to differ

in their need for sleep but also the value of the quality of

sleep experienced. The role of the circadian clock, the dayand-night

cycle in the physiological processes of all living

beings, is surely important. Dr Stickgold's opening statement

discusses the fact that there are more road accidents

immediately after a shift to daylight saving time. Dr Kripke,

in his rebuttal, counters that the effect remains after the

hour is returned in the autumn, which suggests it is the

disruption to the circadian clock that causes the accidents,

rather than the loss of sleep.

The debate has exposed a curious division between those

voting on the proposal and those commenting on it. Threequarters

of voters believe that we are not getting enough

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Economist Debates: Tired workforces

sleep. However, most of the commentators so far do not

intend to sleep any longer than they presently do. Perhaps

this is another example of people saying one thing and doing

another. Or, to borrow an idea from Henry Toland, who

comments from the floor, perhaps it is those who engage

more fully with a debate who have less inclination to sleep.

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Economist Debates: Tired workforces

Defending the motion

Dr Robert Stickgold

Associate professor of psychiatry at Beth Israel Deaconess

Medical Center and Harvard Medical School

The proposer’s rebuttal statement

April 24th 2009

Daniel Kripke has argued that "most of us get enough sleep",

and that "a fair percentage even spend too long in bed". But

what is his argument for this? "These days, average adults in

the United States and much of Europe say they sleep 6.5-7.5

hours a night. In study after study, people who sleep 6.5-7.4

hours live the longest, so the average person is getting

enough sleep. People who report sleeping five or six hours

live almost as long. In fact, people who sleep five or six

hours may live a bit longer than people who sleep eight

hours." Wow!

But there are serious problems with this argument. First, Mr

Kripke slips from talking about how long "[they] say they

sleep" to talking about "people who sleep five or six hours".

No, he means people who say they sleep five or six hours.

Numerous studies have shown that self-reported sleep time,

when obtained in large surveys like those Mr Kripke is

referring to, is highly unreliable. It is really unclear how

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Economist Debates: Tired workforces

much those people really sleep, and whether there are subtle

biases, such as those who exercise a lot being more likely to

under-report their sleep time.

The second problem is what Mr Kripke appears to be

suggesting in this quote, that sleeping five hours a night is

healthier than sleeping eight. Ignoring how most of us feel

after a couple of nights on five hours sleep, studies

performed at the US Army's Walter Reed Hospital and at the

University of Pennsylvania have shown that when subjects

are only allowed five hours of sleep time a night, their

performance on a simple ten-minute vigilance task starts to

crash. The speed with which they respond to test stimuli

drops significantly after just three nights and, after five

nights is 20% slower. Even worse, the number of lapses,

stimuli that subjects take over twice as long as normal to

respond to, increases about tenfold over 14 nights of five

hours in bed. How bad do they get? Their performance

becomes indistinguishable from a group that had been kept

awake for 48-60 hours. Mr Kripke muses on where the idea

that we need eight hours of sleep came from, suggesting

that it probably came "from somebody's grandmother". While

it probably did begin as common sense (and leave my

grandmother out of it), the Walter Reed study discussed

above also showed that the vigilance of subjects limited to

seven hours a night in bed deteriorated steadily over seven

days, while that of longer sleepers did not.

But I think the biggest problem with Mr Kripke's argument is

that it is purely correlative. Yes, people who report sleeping

5-6 hours a night are more likely to be alive five years later

than those reporting 8-9 hours. But University of California

researchers have reported "findings based on millions of

deaths [that] suggest that [people with] shorter, smaller

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Economist Debates: Tired workforces

bodies have lower death rates and fewer diet-related chronic

diseases, especially past middle age, [and that] shorter

people also appear to have longer average lifespans". This

doesn't mean that we should all starve our children to keep

them short (or take drastic actions to make ourselves

shorter). Yes, people who sleep nine or ten hours may tend

to be "very depressed", as Mr Kripke notes, but all the

evidence suggests that depression causes the longer sleep,

not the other way around. In fact, studies have shown that

people who get too little sleep because of sleep-related

breathing disorders are four times more likely to be

depressed than those without such problems. In one study,

improving their sleep by treating the sleep disorder dropped

average symptom ratings to subclinical levels.

What of the claim that "many of the chief proponents of more

sleep are being paid by the sleeping-pill industry"? I agree

that this is problematic, although I challenge Mr Kripke to

point to a published, peer-reviewed study of cognitive,

immune or endocrine impairment caused by inadequate sleep

that he believes is tainted by such payments. Yes, one

estimate is that Americans spend over $100m a year on

sleeping pills to help them sleep, but they spent $750m on

caffeinated energy drinks, while children alone spend over

$1,000m on soft drinks. And don't get me started on coffee.

I am not suggesting that Mr Kripke is in the pay of the

caffeine cartel, but I suspect such businesses spend a lot

more on advertising how their products will keep you awake

than the pharmaceutical industry spends on how theirs will

help you sleep.

But in the end my biggest concern with Mr Kripke's argument

is what is missing: he has no function for sleep. Reading his

opening statement, all I can find is that sleep cures

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Economist Debates: Tired workforces

sleepiness (and causes depression, cancer and early death).

But saying that all sleep does is cure sleepiness is like saying

all eating does is cure hunger, in which case we could cure

hunger in the third world by giving them all amphetamines,

which will decrease their hunger. No, we feel hungry and we

eat because our body needs food to provide us with energy

and nutrients. Similarly, we feel sleepy and we sleep because

our bodies and minds are nourished by sleep. Without

repeating the arguments presented in my opening

statement, we know that sleep enhances our memories, our

immune system and our endocrine system, and that reducing

our total sleep time to five or six hours can massively impair

these sleep-dependent functions. Mr Kripke says that "a fair

percentage even spend too long in bed". But there is little or

no evidence that humans, with the possible exception of

some with major depression, are even able to sleep "too

much". Our bodies know how much sleep they need, and

they tell us. If you sleep longer on the weekend than you do

during the week, your body is telling you that you are not

getting enough sleep.

One last comment: Mr Kripke opines that he "would prefer

that the fellows with their fat fingers on the nuclear red

buttons were getting more sleep". I would like to extend that

to those who teach my children, drive their school bus and

provide their health care; and to my children, my wife and

myself.

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Economist Debates: Tired workforces

Against the motion

Dr Daniel Kripke

Co-director of Sleep Research at the Scripps Clinic Sleep

Center, La Jolla, CA

The opposition’s rebuttal statement

April 24th 2009

"Fat, sick, and stupid", that is the kind of scare tactics that

are being used to worry people about their sleep. Increasing

fear may sell sleeping pills and unnecessary sleep clinic

recordings, but advice to be afraid of too little sleep is not

based on sound medical evidence.

Does too little sleep make you fat? In Japan and China,

obesity has no substantial relationship to sleep duration. In

North America, people with very short sleep patterns tend to

be fat, but women with long sleep patterns also tend to be

fat. Data from Europe (e.g. Finland) are a bit murkier. If

there is really a biological mechanism by which shorter sleep

causes fatness, why do those with short sleep in Japan and

China have normal weights? There must be social factors in

America which associate short sleep and obesity. For

example, in America, poverty and low social class are

associated with both obesity and short sleep.

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Economist Debates: Tired workforces

The scare tactics repeat mumbo-jumbo about ghrelin, leptin

and pre-diabetes taken from brief laboratory experiments,

without mentioning the flaws in those experiments or the

larger studies which contradict them. In the Nurses Health

Study of 70,000 women followed for ten years, after

controlling for age, alcoholism, obesity and so forth, those

who slept less than eight hours did not develop significantly

more diabetes overall. Those who slept nine hours or more

did develop significantly more diabetes than those who slept

seven or eight hours. In an "NHanes" US government survey

sample, those who slept six, seven or eight hours had about

the same risk of developing diabetes. Those who slept five

hours or less and those who slept nine hours or more had

about the same increased risk. In a study from Japan, sleep

duration was not related to developing diabetes. In a study

from Finland, sleep duration had nothing to do with diabetes

in men, but women who slept eight hours or more were more

likely to develop diabetes, as well as those who slept six

hours or less. This was no endorsement for eight hours'

sleep.

Many of us feel hungry for junk food when it really is not a

good idea to eat it. If you ask people, they would admit they

are tempted by a second helping. Similarly, if you ask

people, they will often say they would like more sleep. That

does not prove that more sleep would be good for them, any

more than extra junk food.

I would not want anybody to think that sleeping pills can

prevent infection. On the web page of the Journal of Clinical

Sleep Medicine, there is an "Accepted" article showing that in

drug company trials, patients randomised to receive sleeping

pills averaged 44% more reports of infections than those

randomised to receive placebos. Draw no conclusions from

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Economist Debates: Tired workforces

mumbo-jumbo about the immune system being suppressed

by sleep deprivation. In fact, some immune elements are

stimulated by sleep loss.

People claim that daytime sleepiness causes road accidents,

when the fact is that the sleep-related road accident rate

goes up late at night. It is driving late at night—or unusual

occasions causing sleep loss—which cause most sleepiness

on the road. People who stay up unusually late, such as

physicians called to duty at night, have extra driving risk and

risks of mistakes, but that does not prove that the regular

sleep patterns of the general population are too short.

Physicians have no demonstrated extra driving risk on days

which do not follow night calls. Moreover, I beg your pardon,

physicians have no special tendency to become "fat, sick,

and stupid", nor would it save lives if all doctors refused

night calls.

People confuse the impairments caused by disrupting the

body clock with the impairments caused by sleep loss, when

the body clock effects are generally more important. One

proof is in the time change data. The automobile accident

rate goes up in the autumn shift to standard time, when we

are offered an extra hour of sleep, as well as in the spring

when the switch to daylight savings might cost us a few of

our 40 winks.

Quoting different laboratory experiments, one can claim all

sorts of things about sleep loss effects on mental ability. One

of the most quoted experiments recruited volunteers who

said they needed eight hours sleep (e.g. more than the

current average), and then reduced their sleep to less than

six hours or less than four hours for a couple of weeks,

denied them their usual coffee and also denied them normal

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Economist Debates: Tired workforces

light exposure. After a week or two, those allowed less than

six hours sleep were not reported to have statistically

significant deterioration in sensitive performance tasks,

although those with less than four hours did show distinct

deterioration.

My colleague Shawn Youngstedt recently persuaded some

older people who said they needed over 8.5 hours sleep a

night to reduce their time in bed by 1.5 hours at home. By

continuous home measurement, they reduced time in bed 82

minutes on average. As compared with a control group not

asked to reduce time in bed, the volunteers who reduced

time in bed over eight weeks showed no significant

differences in sensitive measures of performance, in reported

sleepiness, in mood, or in quality of life. The most interesting

relationship was that the more subjects reduced their time in

bed, the more alert they were.

Bill Gates said he likes to get seven hours of sleep but was

getting much less when he was founding and building

Microsoft. I would be very skeptical that sleep loss made Mr

Gates stupid.

To summarise, the scare stories about a sleep-deprived

population are based on a biased selection of small shortterm

laboratory experiments. There is no evidence for the

majority of the American and European populations that they

are harming themselves by choosing too little sleep.

Specifically, there are no large, long-term experimental trials

which show any such thing.

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Economist Debates: Tired workforces

Featured guest

Dr Thomas J. Balkin

Chief of the Department of Behavioral Biology at the Walter

Reed Army Institute of Research (WRAIR)

Thomas J. Balkin is chief of the Department of Behavioral

Biology at the Walter Reed Army Institute of Research

(WRAIR). He is recognised internationally for his research in

the areas of sleep and performance, functional neuroimaging

during sleep, the psychopharmacology of sleepinducing

and stimulant medications, and sleep deprivation.

He is also a Diplomate, American Board of Sleep Medicine, a

Fellow of the American Academy of Sleep Medicine and a

member of the Sleep Research Society. He currently serves

as an ex-officio member of the National Sleep Disorders

Center Sleep Disorders Research Advisory Board (SDRAB) at

the National Institute of Health, as vice-chair on the board of

directors of the National Sleep Foundation (NSF); and as an

associate editor for the journal SLEEP.

35


Economist Debates: Tired workforces

Featured guest, Dr Thomas J.

Balkin

April 24th 2009

Asking whether we are getting enough sleep is a lot like

asking whether we are making enough money. A good

argument can be made for wanting more of both. But the

answer to this question actually depends on what we mean

by "enough".

Clearly, total sleep deprivation (for example, staying awake

continuously for 36 hours) has deleterious effects on

psychomotor performance (e.g. simple reaction time) and a

host of mental abilities like judgment, problem-solving,

humour appreciation and risk-taking (for recent review and

discussion see Balkin et al., 2008). Indeed, sleep loss and

sleepiness have been implicated as possible contributory

factors in several spectacular industrial mishaps over the

years, including the meltdown at Chernobyl, the grounding of

the Exxon-Valdez tanker and the release of poisonous gas at

Bhopal. One cannot help but wonder whether any or all of

these modern catastrophes might have been averted—by

virtue of eliminating or mitigating the human errors that

contributed to these events—had certain key workers

obtained only a few more hours of sleep before their work

shifts.

Less spectacular but also striking are the more insidious

effects that chronic sleep restriction (obtaining less sleep

than needed to feel fully refreshed for weeks, months, or

even years on end) may be having on our society. There is

36


Economist Debates: Tired workforces

growing evidence that sleep restriction produces changes in

human physiology that contribute to weight gain and, by

extension, to all of the health problems that accrue as a

function of excess body weight (for review see Van Cauter

and Knutson, 2008).

According to the 2008 "Sleep in America" poll by the National

Sleep Foundation, American workers average 6 hours and 40

minutes of sleep per night, significantly less than the 7-8

hours of nightly sleep that is typically recommended (e.g.

NIH Pub No. 06-5271, 2005). In addition, according to the

2004-06 National Health Interview Survey, approximately

21% of adults in the United States typically obtain 6 or fewer

hours of sleep per 24 hours (Schoenborn and Adams, 2008).

If those with sleep disorders (e.g. sleep apnea, insomnia) are

included along with those who are chronically sleep-restricted

for other reasons (e.g. shiftwork), it is estimated that 70m

Americans experience chronic sleep loss (NIH Pub No. 06-

5271, 2005), and therefore experience corresponding deficits

in alertness and performance capacity on a daily basis. It has

been estimated that such sleepiness-induced performance

deficits cost the world economy billions of dollars per year in

accidents or direct health care costs and lost operational

efficiency and productivity.

So, if by enough sleep we mean enough sleep to maximise

productivity and minimise errors and accidents in operational

settings", the answer is no, we are not getting enough sleep.

If by enough we mean enough sleep to do our jobs with

nominal efficiency and mostly avoid catastrophic errors and

accidents, then the answer is generally yes, we are getting

enough sleep.

However, there is an important caveat to both answers: "We"

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Economist Debates: Tired workforces

are actually a distribution of individuals, with individual sleep

requirements, sleep habits, job requirements, performance

capacities and differential levels of resilience to the effects of

sleep loss. At one tail of this distribution are those of us who

regularly obtain less than six hours of sleep per night,

because of work schedules or other demands upon our time,

and/or because we have, over time, become inured to

subjective sleepiness and now mistakenly believe that six or

fewer hours of sleep is all that is needed for optimal health

and performance. It is this tail of the distribution that

accounts for most of the health and performance-related

problems that accrue with inadequate sleep. So, naturally, it

is improved sleep in this tail of the distribution that would

ultimately yield the greatest benefits to society.

Disclaimer

This material has been reviewed by the Walter Reed Army Institute of Research, and

there is no objection to its presentation and/or publication. The opinions or assertions

contained herein are the private views of the author and are not to be construed as

official or as reflecting the position of the Department of the Army or the Department of

Defense.

References

Balkin, T.J., Rupp, T., Picchioni, D., Wesensten, N.J. (2008) "Sleep loss and sleepiness:

current issues", Chest, 134(3), 653-60.

Van Cauter, E., Knutson K.L. (2008) "Sleep and the epidemic of obesity in children and

adults", European Journal of Endocrinology, 159 Suppl 1: S59-66.

National Heart, Lung, and Blood Institute (2005) Your guide to healthy sleep. National

Institutes of Health. NIH Pub No. 06-5271. Department of Health and Human Services

(November).

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Economist Debates: Tired workforces

Schoenborn, C.A., Adams, P.F. (2008) "Sleep Duration as a Correlate of Smoking,

Alcohol Use, Leisure-Time Physical Inactivity, and Obesity Among Adults: United States,

2004-2006", Division of Health Interview Statistics (May). Available online at:

http://www.cdc.gov/nchs/products/pubs/pubd/hestats/sleep04-06/sleep04-06.pdf

39


Economist Debates: Tired workforces

Featured guest

Professor Jim Horne

Director, Sleep Research Centre at Loughborough University

Professor Jim Horne runs the Sleep Research Centre at

Loughborough University, UK, and until last year was the

founding editor of the Journal of Sleep Research. He is the

author of "Why We Sleep" (Oxford University Press 1988)

and the more popular book "Sleepfaring—A Journey Through

the Science of Sleep" (OUP, 2007). His main interests lie in:

the functions of sleep and the effects of sleep loss on body

and brain; what is sleepiness; sleep debt and whether our

society is chronically deprived; and sleep-related accidents.

His work in these areas has been published extensively in the

scientific literature.

40


Economist Debates: Tired workforces

Featured guest, Professor Jim

Horne

April 28th 2009

We are getting enough sleep

"The subject of sleeplessness is once more under public

discussion. The hurry and excitement of modern life are held

to be responsible for much of the insomnia of which we hear;

and most of the articles and letters are full of good advice to

live more quietly and of platitudes concerning the

harmfulness of rush and worry. The pity of it is that so many

people are unable to follow this good advice and are obliged

to lead a life of anxiety and high tension." British Medical

Journal, September 29th 1894 (p 719).

Plus ça change, such is the human condition. Nevertheless,

again, it is being advocated that chronic sleep loss (sleep

debt) is endemic in western adult populations, and even the

average 7.0-7.5 hours' nightly sleep is inadequate. The belief

that we used to sleep nine hours a night largely stems from a

misinterpreted study published in 1913, based only on

schoolchildren. Other claims that we slept better often rely

on vague findings that more people felt rested and had more

stamina in those days, but such terms do not necessarily

implicate sleeplessness. Besides, UK population studies over

the last 40 years consistently show no change, with the

average daily sleep for healthy adults being around 7.25

hours. And, of course, Daniel Kripke and colleagues have

shown that mortality happens to be lowest at this level, with

recent findings further confirming this.

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Economist Debates: Tired workforces

Many people when asked the leading question "Would you

like more sleep?", will say yes, in the same manner they

would like more pay, a larger house and longer vacations,

etc. However, we have found from a very large survey that,

despite saying yes, people are reluctant to make time for this

extra sleep if they have to forgo alternative waking

pleasures. It is all very well to exhort people to take more

sleep, but few will do so.

Assertions that healthy adults who do not complain of

daytime sleepiness may, unknowingly, have chronic

sleepiness, are largely derived from very sensitive

experimental laboratory tests able to eke out the last

quantum of sleepiness; thus we should be circumspect about

generalising from these data to society at large. Although

people may be complaining of tiredness and fatigue, which

maybe indicative of sleep debt, such terms are not

necessarily synonymous with sleepiness, which has much

wider connotations, unlikely to be rectified by extra sleep.

Short sleep can indicate depression, and a disproportionately

high number of short sleepers are depressed, but while some

scientists suggest that more sleep improves mood, this effect

is more likely to be due to an earlier bedtime, not from

having more sleep.

Just because we can easily take more than our usual amount

of sleep, in a lie-in for example, this may simply reflect

boredom or pleasure, and not necessarily making up for lost

sleep. Similarly, we can easily eat and drink to excess, for

pleasure, without hunger, thirst or underlying physiological

needs. Zoo animals, for example, sleep much longer in

confinement than when in the wild, presumably, because

they are bored and well fed.

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Economist Debates: Tired workforces

Concerning the issue of pre-diabetic states being linked to

short sleep, laboratory studies only point to this effect when

sleep is restricted to abnormally low levels, typically, to four

hours per night, which is impossible to maintain for more

than a few nights, and when there is very evident excessive

sleepiness and signs of stress. No study can demonstrate

that chronic short sleep itself, whether it be in adults or

children, causes more than a very slow weight gain; unlikely

to be greater than 1-2 kg a year, and accumulating over

many years. The minimum amount of sleep people can cope

with in the long term is about five hours of quality sleep a

night, and still with only a minority of these sleepers being

obese. This approximately two-hour sleep difference between

them and the average sleeper accrues to many hundreds of

hours of lost sleep a year. Similarly, what is at best a small

and very slowly developing increase in blood pressure or

even diabetes can evolve over many years with such short

sleep. There is no evidence to support the notion that obese,

diabetic or hypertensive people could expect these problems

to reverse with more sleep, or that sleeping tablets will cure

these disorders. In fact, excess sleep also leads to these

same problems. Putting all this in perspective, relatively few

obese adults or children are very short sleepers, and few

very short sleeping adults or children are obese or suffer

obesity-related disorders. However, it must be said that

insufficient sleep in children, which is an increasing problem,

undoubtedly causes behavioural problems that must be of

greater concern.

Claims that more sleep improves memory are often based on

statistically significant findings that, arguably, are not of

sufficient magnitude to warrant a real need for longer sleep,

but only point to the need for a more discerning cost benefit

43


Economist Debates: Tired workforces

analysis of striving for a society devoid of any sleepiness. Of

course, the greatest danger to health from grossly

insufficient sleep is not from becoming obese and so on, but

in having an injurious accident related to sleepiness.

However, claims that sleep debt is responsible for vehicle

collisions are overstated, as many of these drivers, crashing

during the small hours of the morning, well beyond their

usual bed-time, have had no sleep,.

Advocating the need for more sleep unnecessarily creates

further worries among insomniacs, unfounded health

concerns and even a greater demand for sleeping aids.

Instead of assuming that more sleep will improve health,

reduce the metabolic syndrome, obesity and so on, the

obvious and rapid way of losing weight and improving

physical well-being is to devote more time not to sleeping

but to exercising and contemplating a reduced-calorie diet.

44


Economist Debates: Tired workforces

Closing statements

Closing statements were originally published on April 29th

2009. They can be viewed online at

http://www.economist.com/debate/days/view/303

The moderator

Alison Goddard

Science Correspondent, The Economist

The moderator’s closing statement

April 29 th 2009

Everybody sleeps. The phenomenon has been studied for

centuries, as one of our featured guests, Jim Horne, points

out. So why the debate? Surely the question of whether we

are getting enough sleep has been adequately addressed by

now.

As this debate has shown, the answer is far from settled.

Sleep scientists have delved into how and why people sleep

and, as they have done so, the subject has become ever

45


Economist Debates: Tired workforces

more complex and fascinating. As Robert Stickgold says,

researchers still do not know what is the right measure of

sufficient sleep. Many of the people who have commented on

this debate would appear to agree with this point. Sleep is

not just about spending a certain number of hours

unconscious. The time at which someone falls asleep and

awakes is important, as is the pattern of sleep. Interrupted

slumber appears to be less satisfying than a full night's

sleep.

Sleep scientists have not only neglected to identify what

constitutes sufficient sleep, they have also yet to fully

establish why it is that people sleep at all. Just think what

people could accomplish if they could only reclaim the third

of their lives that they spend asleep. Yet sleep is vital. Good

health cannot be achieved without it. And, as "Widtsoe of the

82nd", who comments from the floor, points out, those who

are denied sleep soon fail to function properly.

Thomas Balkin, a featured guest, has seized on what is

meant by "enough". He says, "If by enough sleep we mean

enough sleep to maximise productivity and minimise errors

and accidents in operational settings, the answer is no, we

are not getting enough sleep. If by enough we mean enough

sleep to do our jobs with nominal efficiency and mostly avoid

catastrophic errors and accidents, then the answer is

generally yes, we are getting enough sleep."

Certainly the question of whether we are getting enough

sleep is one that merits further scientific study. Perhaps that

is what "thegiraffe" means when he or she appeals for the

debate to return to "content over instinct". Both Daniel

Kripke and Jim Horne liken sleeping to eating. I suspect that

many people have thought more deeply about eating than

46


Economist Debates: Tired workforces

they have about sleeping. If the question had been "Are we

getting enough food?", the outcome would surely be

different.

47


Economist Debates: Tired workforces

Defending the motion

Dr Robert Stickgold

Associate professor of psychiatry at Beth Israel Deaconess

Medical Center and Harvard Medical School

The proposer’s closing statement

April 29th 2009

Let me first extend my thanks to Daniel Kripke, our featured

guests and those in the general public who have responded

to this debate for their thoughtful comments. I want to start

by addressing some of your comments. First, if you are about

to go to your doctor to ask for sleeping pills because of what

Mr Kripke described as my "scare tactics", please don't! I

hope most readers understood my phrase "fat, sick and

stupid", as ironic hyperbole. Despite the fact that my lab and

I have received a lot of money from drug companies (I

receive research funding from and consult to Actelion

Pharmaceuticals, Merck and Sepracor), I don't like the idea

of taking sleeping pills, and think most of them produce

deleterious side effects on the structure of your sleep.

Several readers suggested that sleep quality can be more

important than quantity and that sleep disorders can impair

sleep quality, that work and home obligations prevent them

from getting as much sleep as they want, that the trade-off

48


Economist Debates: Tired workforces

between sleep time and productivity drives them to sleep les,

and that people need dramatically different amounts of sleep.

To all of these, I say "Amen". All of these need to be factored

into our discussion.

Next, let me respond to a few of M. Kripke's comments,

which I believe are disingenuous. In his rebuttal, he stated,

as Alison Goddard noted, that yes, road accidents go up the

Monday morning after Americans lose an hour of sleep to

daylight savings time each spring, but it also goes up when

they regain the hour's sleep in the autumn. What he did not

say is that the study by Varughese and Allen (2001), to

which he was referring, concluded that the increased

accidents in the autumn, when the hour was regained,

actually occurred Saturday night, when people apparently

stay up later than usual, in anticipation of the extra hour's

sleep the next morning. Mr Kripke knows this. Perhaps

tactically it was a clever argument to make in a debate, but it

is dangerous to misrepresent these findings to the public.

Another flagrant example of Mr Kripke's bad faith is his quote

that the Nurses Health Study (Ayas et al., 2003) indicated

that short sleep was not associated with a higher risk of

developing diabetes. True, short sleep did not predict nonsymptomatic

diabetes, which made up the bulk of the cases,

but it did predict "symptomatic diabetes", that is, severe

diabetes with medical complications. He knows this as well.

I particularly take umbrage at his reference to my

"repeat[ing] mumbo-jumbo about ghrelin, leptin and prediabetes

taken from brief laboratory experiments … without

mentioning larger studies which contradict them". My

dictionary defines mumbo-jumbo as language "intending to

cause confusion or bewilderment". Well shame on the Revue

49


Economist Debates: Tired workforces

Neurologique (Paris), the Annals of the New York Academy of

Science and the British journal, Lancet (described in

Wikipedia as "one of the world's best-known and most

respected general medical journals") for publishing this

trash. I don't think this kind of mud-slinging furthers the

debate. As for his comment about ignoring "larger studies", a

recent meta-analysis of 52 studies of sleep and obesity,

including over 130,000 subjects, concludes that "there is

good evidence for a cross-sectional association between

short sleep and higher risk of obesity".

So why is there disagreement even among sleep

researchers? Aside from some instances of unfair and biased

reviews, I think that the main problem is that we still do not

know what the right measure of sufficient sleep is. If

someone drinks five cups of coffee a day and feels that they

are functioning just fine, are they getting sufficient sleep? If

someone can get their temperature down to normal by taking

two extra-strength Tylenol, does that mean that they are not

sick? But even putting caffeine aside, subjective assessments

of sleepiness are reliably inaccurate. Based on studies of 117

subjects who spent a total of 1,700 days and nights in the

sleep laboratory, David Dinges has come to the conclusion

that "as chronic sleep restriction continue[s], subjective

awareness of sleepiness [is] altered and uncoupled from

objective performance deficits", with subjects failing to

recognise continued deterioration in their cognitive

performance (Dinges, 2004). On the flip side, there is no

evidence that people think they need more sleep than

objective measures indicate they need for maintaining

normal cognitive functioning.

Another approach is to determining how much sleep we need

is to look at our general wake-sleep habits. People who sleep

50


Economist Debates: Tired workforces

longer on weekends appear to do so in an attempt to recover

from insufficient sleep during the week, so that is one

indication of who is not getting enough sleep. Selfmedication

is another measure. In all likelihood, the vast

majority of people drinking coffee in the morning are doing

so, consciously or unconsciously, to correct from sleepiness

due to inadequate sleep quantity or quality.

But a bigger problem remains. We have not confidently

delineated the actual functions of sleep, so we cannot say

how much sleep we need to meet their demands. How much

sleep (correcting for sleep quality) people need to prevent

diabetes (and Mr Kripke agrees that sleep affects your risk of

developing diabetes), to optimise immune responses (which,

again, Mr Kripke agrees is affected by sleep) and to

maximise sleep-dependent memory processes (which he is

notably silent about), as well as how these numbers relate to

one's perceived sleep needs, remains to be finally settled.

Still, all in all, the best guess of most sleep researchers who

have weighed in on the subject is that most of us (not all of

us) are not getting enough sleep.

In closing, let me just comment on Mr Kripke's statement

that Bill Gates got less than seven hours of sleep for many

years, and does not appear to be "stupid". Mr Gates has also

been quoted as saying that his programmers are so

dedicated that, when a deadline is approaching, they would

program 72 hours straight, without sleep. I suspect the

product was Windows ® .

References

Ayas, N. T., White, D. P., Al-Delaimy, W. K., Manson, J. E., Stampfer, M. J., Speizer, F.

E., et al. (2003) "A prospective study of self-reported sleep duration and incident

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Economist Debates: Tired workforces

diabetes in women", Diabetes Care 26(2): 380-4.

Dinges, D. F. (2004) "Sleep debt and scientific evidence", Sleep 27(6): 1050-2.

Varughese, J. and Allen, R. P. (2001) "Fatal accidents following changes in daylight

savings time: the American experience", Sleep Med 2(1): 31-6.

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Economist Debates: Tired workforces

Against the motion

Dr Daniel Kripke

Co-director of Sleep Research at the Scripps Clinic Sleep

Center, La Jolla, CA

The opposition’s closing statement

April 24th 2009

Most of us have chosen to cut down on our sleep from time

to time. We know what the consequences are. We know that

we do not suffer some horrifying loss of intelligence or

memory every time we get less than eight hours of shut-eye.

The effects are hardly as drastic as Robert Stickgold claims.

We make deliberate choices to sleep seven hours or six

hours, feeling that the practical benefits of having the extra

time outweigh whatever sleepiness might result from

sleeping less than eight or nine hours. Most of us are not at

all sleep-deprived, in the sense that somebody is depriving

us of sleep or arranging situations (such as military duties)

where we cannot sleep as we should. Most of us sleep less

than eight hours because it works out well for us. Where is

Mr Stickgold's proof that we do not know what we are doing?

The problem with running a scare campaign with lurid stories

about becoming "fat, sick and stupid" is that fear about sleep

may encourage people to try to sleep more than they need,

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Economist Debates: Tired workforces

even more than they easily can. I often see patients who feel

well-rested after six or seven hours' sleep but have been

worried they are not sleeping enough because of all this

scare publicity. The problem is that if people spend too long

a time in bed, they may develop insomnia, anxiety and

depression because they are spending too long in bed

worrying about sleep. Laboratory studies show that many

people feel worse after more sleep. A person can try too hard

to sleep. Insomnia is a common cause of discomfort. One of

the best-proven treatments for insomnia is restricting time in

bed and persuading people to worry less about it.

The other reason I speak out about the sleep scare campaign

is that I have seen the harm which sleeping pills do. People

come to our sleep clinic after sleeping pills have messed

them up. Looking at the high mortality rates of people who

take sleeping pills, one can estimate that sleeping pills kill

several times as many people as those who may die from

falling asleep at the wheel. Incidentally, there is plenty of

evidence that sleeping pills increase driving accidents. It is

hard to estimate accurately, but epidemiology suggests that

sleeping pills may be killing far more people in Europe and

America than the terrorists of al-Qaeda. I have worked in

sleep medicine long enough to know perfectly well that the

sleeping pill companies are behind much of the scare

campaign about the perils of sleep loss.

Since Mr Stickgold challenged me to point out an article

about cognitive, endocrine, or immune effects of short sleep

tainted by sleeping pill company payments, it seems I must

point out that Mr Stickgold's statements in this very debate

are tainted. According to one of his recent papers, "Dr.

Stickgold has received research support from and consulted

for Takeda, Actelion, and Sepracor". Takeda and Sepracor

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Economist Debates: Tired workforces

sell sleeping pills and Actelion has been developing one. It

appears that Mr Stickgold has been working for these

sleeping pill companies part-time. I wonder why he did not

disclose this conflict of interest. One of his tainted

statements was "Americans spend over $100m a year on

sleeping pills", which falsely minimised the problem, since

the real 2008 sleeping pill retail sales in the United States

were between $3 billion and $4 billion.

Mr. Stickgold scoffed at the idea that we might restrict the

calories that our children get, at the same time pretending to

be worried about obesity and diabetes. He makes no sense.

In fact, many experts argue that more dietary restriction

would be good for most of us. If dietary restriction can be

good, and most of us have put ourselves on diets, could not

sleep restriction be similar? A little sleep restriction might

make you a bit sleepy (it did not in Dr Youngstedt's

experiment with reducing time in bed), but a diet makes us

hungry, and both might be good for us. I do not argue that

most people should sleep even less than they do now, but

that the majority of us who sleep less than eight hours have

made a demonstrably healthy choice.

Though questionnaires were used in the largest studies

showing that those sleeping less than eight hours live the

longest, there have been some studies using objective sleep

recording which showed the same thing. Discrepancies

between reported and recorded sleep cannot explain the

evidence that those sleeping less than eight hours live longer

and are generally healthy. One of the readers wondered if

these studies were controlled for other risk factors such as

exercise, and of course they were indeed controlled for many

other risk factors.

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Economist Debates: Tired workforces

It is true that most of the evidence favouring less than eight

hours' sleep is epidemiologic, and you might call it

correlational. Mr Stickgold's arguments were also based

entirely on possible correlations of ghrelins or vaccine

antibody responses or laboratory computer games, etc, with

what might happen in everyday life. The longest experiments

randomising sleep length in everyday life (those of Dr

Youngstedt and that of Hoch1 and colleagues showed more

benefit than risk in reducing sleep. Mr Stickgold's side never

did equivalent experiments. Specifically, there has never

been a long-term community-based experiment which

supported his claims that reducing sleep to less than eight

hours makes people fat, sick and stupid. Since we certainly

have large, long-term experimental studies of weight

reduction, low-fat diets, exercise and so forth, I have called

for similar experimental studies which contrast the effects of

different long-term sleep durations. Only long-term clinical

trials exploring the benefits and risks of different sleep

durations could give a definitive answer to the proposition we

now debate. We also need larger, long-term studies of

sleeping pills, to follow-up on the epidemiologic evidence that

people who take sleeping pills tend to die early. Such longterm

clinical trials would give us all much firmer information

about whether we are getting enough sleep.

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Economist Debates: Tired workforces

Winner announcement

The winner announcement was originally published on May

1st 2009. It can be viewed online at

http://www.economist.com/debate/days/view/307

The moderator

Alison Goddard

Science Correspondent, The Economist

Winner announcement

May 1 st 2009

Final vote: Pro:75% Con:25%

After ten days of hotly-contested debate, we have a verdict.

Some 75% of voters agree with the proposition: "This house

believes that we are not getting enough sleep."

The voting has remained remarkably consistent throughout

the debate. Hundreds of you voted, but the number of people

who changed sides during the debate can be counted on the

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Economist Debates: Tired workforces

fingers of one hand. The appeals of the speakers and the

featured guests would appear only to have confirmed views

that were already firmly entrenched.

Many of the commentators from the floor spoke passionately

about their own experiences of lack of sleep. One of the most

popular comments came from "Gianran", who blames his

tiredness, which he says leads to poor performance at work,

on staying up late to read The Economist. His comment

illustrates beautifully what, to my mind, was the main

sticking point in the debate. Yes, most people would like

another hour in bed when the alarm clock signals the start of

the working day. But would the same people consider going

to bed an hour early, thereby depriving themselves of the

hard-won and luxurious leisure time that evening presents, in

order to achieve this? I suspect that only the truly sleepdeprived—those

to whom sleep has been denied through

working long and antisocial hours—would avail themselves of

such an opportunity.

This house believes that we are not getting enough sleep.

But this house does not appear to intend to mend its ways in

order to get more sleep. The workforce will thus remain tired

and inefficient or, at least, its members will report that they

do not get enough sleep. Indeed, the present economic

climate may further reduce the hours people spend asleep.

Either people will be working longer hours, reducing the time

they have available for sleep, or they will be kept awake by

worrying about what the future holds.

I should like to thank both the speakers, the three featured

guests, everyone who commented from the floor and

everyone who voted, for contributing to what has been a

thought-provoking debate. Although the votes have been

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Economist Debates: Tired workforces

counted and the winner declared, you can still comment on

the debate and its outcome until Friday May 8th. I look

forward to reading your further thoughts.

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Economist Debates: Carbon offsets

Background reading

Science & Technology: Questioning the purpose of sleep

Science & Technology: Memory formation and sleep

deprivation

Science & Technology: Dreams are made of this

Christmas specials: And so to bed

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Economist Debates: Carbon offsets

The supporter: Phillips

Interview with Dr David White,

Chief Medical Officer, Philips Home

Healthcare Solutions

April 21 st 2009

Q: At what point in our lives is getting enough sleep

most important? We have bed-times when we are

young, but is sleep more important when we are old?

A: Infants, children and adolescents need more sleep than

adults. It is also more important not to lose sleep when we

are young. For instance, kids with sleep apnea (a condition in

which the airway collapses during sleep, preventing proper

respiration) don't do as well in school as non-apneic children.

We don't know why this is. But if I was to guess, I would

speculate that there is substantial neural processing going on

when infants and children sleep that makes sleep more

important for them than for adults.

Once we reach the age of 25, our need for sleep stays

constant. We used to think that the elderly need less sleep.

The view now is not that elderly people need less sleep, but

that they have a diminished ability to sleep, and that, when

deprived of sleep, they become as dysfunctional as younger

people.

Q: Are people's sleeping patterns noticeably different

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Economist Debates: Carbon offsets

today from how they were, say, ten or 20 years ago?

A: Self-reported data suggests that people are getting less

sleep. The National Sleep Foundation, for instance, publishes

data that shows a gradual decline in the time people spend

asleep. The broad picture shows that while we were getting

between 8.0–8.5 hours of sleep per night at the end of the

19th century, we are now getting 6.5–7.0 hours.

Q: Why are we sleeping less?

A: One answer is that we now have access to artificial light

sources. We also have lots of entertainment available to us.

About 25% of us do shift work, and that makes it more

difficult to sleep well. We also suffer from job pressures and

financial worries.

Q: Is it also because we get less physical exercise?

A: There are some data that suggest exercise improves

sleep. But note that these data show that exercise improves

the quality of sleep—how much of the time we spend in deep

sleep—and not necessarily the amount of time we spend

asleep.

Q: Do you anticipate that the current economic climate

will have a palpable effect on the amount of sleep

people get?

A: Let's break this down into the two ways people get less

sleep. The first is because of insomnia, in which people try to

sleep but fail. The second is because people set aside less

time for sleep. Both of these could be affected by the current

economic situation. People are experiencing more anxiety—

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Economist Debates: Carbon offsets

about their job or finances—and that is a cause of insomnia.

People might also be setting aside less time for sleep

because they are working longer hours, or working two jobs.

Q: Are there particular groups of people who are more

prone to sleeplessness?

A: Insomnia is more prevalent among women than men,

among lower socio-economic groups, among older people

and among people with psychiatric diseases.

Q: What are the medical effects of having too little

sleep or, on the other hand, too much?

A: For people who get 5–6 hours of sleep a night, effects can

include a shortened lifespan, increased risk of heart attacks

and high blood pressure, problems with insulin and glucose

regulation, a suppressed immune function and raised levels

of the hormones which drive appetite, leading people to eat

more.

If, on the other hand, you look at people who are getting 9–

10 hours of sleep a night, things start to go in the same

direction. So we have a U-shaped curve. However, most

people think there is no causality between too much sleep

and these health problems. The cause lies elsewhere: for

example, depression. However, the feeling is that there is a

causal relationship between too little sleep and these health

problems.

Q: How are we tackling insomnia?

A: There are a set of cognitive behavioural therapies that can

help with insomnia. These range from spending less time in

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Economist Debates: Carbon offsets

bed to learning relaxation techniques. The problem here is

that it takes a lot of effort to make these therapies work,

often in concert with a clinical psychologist. Thus, we would

need a lot of trained professionals to cope with the number of

people who are having trouble sleeping. So a lot of people

end up taking sleeping pills.

Pills will help you sleep better, and for a longer period of

time. But they are not a fix. They also have side-effects, such

as short-term memory loss. Older insomniacs run a

heightened risk of falling when they get out of bed at night.

There is also evidence that they increase the risk of

automobile accidents. On the other hand, people with

insomnia who get very little sleep because they are not

taking medication may also have a higher risk of being

involved in an automobile accident.

Q: What is Philips' interest in sleep?

A: As a health and well-being company, Philips has become

increasingly interested in sleep, particularly with the

acquisition of the company Respironics, a global leader in

treating obstructive sleep apnea. Looking towards the future,

Philips is also becoming interested in innovations that

address insomnia and sleep duration via direct-to-consumer

products. These include stimulation devices that help induce

sleep and tools to aid relaxation and help with cognitive

behavioural therapies without the need of an expert. Philips

is also interested in circadian disorders. These affect shift

workers and jet-lagged travellers and can be addressed using

novel ways to reset the body clock. It turns out that the most

effective way to reset the body clock is by using light—and

Philips is good at light.

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Economist Debates: Carbon offsets

Q: If there was one misperception you want to set

straight about sleep, what would it be?

A: Sleep is not optional. You can go without it, but you will

pay a price.

David P. White MD is the Chief Medical Officer for Philips Home Healthcare Solutions.

Dr White was first appointed Chief Medical Officer for the company Respironics in May

2006 and continues his role following the acquisition of the company by Philips in March

2008. Dr White is responsible for clinical research strategies and programmes, advising

senior management on key medical issues, and serving as a liaison between Philips

Home Healthcare Solutions group and the sleep and respiratory medical communities.

Dr White is board-certified in sleep disorders medicine, internal medicine, pulmonary

disease and critical care medicine. Until recently he served as director of the Clinical

Sleep Disorders Program at Brigham and Women's Hospital—and remains as a

Professor of Sleep Medicine at Harvard Medical School, both in Boston. He has held

many leadership roles in professional sleep and pulmonary societies, including serving

as the Editor-in-Chief of the journal Sleep.

Dr White holds a Bachelor of Science degree from Washington and Lee University in

Lexington, Virginia and his Medical Degree from Emory University School of Medicine in

Atlanta, Georgia. He did his post-doctoral internship and residency in internal medicine,

as well as a pulmonary fellowship, at the University of Colorado Health Science Center.

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