The myth of the eight-hour sleep

 
Woman awake

We often worry about lying awake in the middle of the night - but it could be good for you. A growing body of evidence from both science and history suggests that the eight-hour sleep may be unnatural.

In the early 1990s, psychiatrist Thomas Wehr conducted an experiment in which a group of people were plunged into darkness for 14 hours every day for a month.

It took some time for their sleep to regulate but by the fourth week the subjects had settled into a very distinct sleeping pattern. They slept first for four hours, then woke for one or two hours before falling into a second four-hour sleep.

Though sleep scientists were impressed by the study, among the general public the idea that we must sleep for eight consecutive hours persists.

In 2001, historian Roger Ekirch of Virginia Tech published a seminal paper, drawn from 16 years of research, revealing a wealth of historical evidence that humans used to sleep in two distinct chunks.

A woman tending to her husband in the middle of the night by Jan Saenredam, 1595 Roger Ekirch says this 1595 engraving by Jan Saenredam is evidence of activity at night

His book At Day's Close: Night in Times Past, published four years later, unearths more than 500 references to a segmented sleeping pattern - in diaries, court records, medical books and literature, from Homer's Odyssey to an anthropological account of modern tribes in Nigeria.

Much like the experience of Wehr's subjects, these references describe a first sleep which began about two hours after dusk, followed by waking period of one or two hours and then a second sleep.

"It's not just the number of references - it is the way they refer to it, as if it was common knowledge," Ekirch says.

During this waking period people were quite active. They often got up, went to the toilet or smoked tobacco and some even visited neighbours. Most people stayed in bed, read, wrote and often prayed. Countless prayer manuals from the late 15th Century offered special prayers for the hours in between sleeps.

And these hours weren't entirely solitary - people often chatted to bed-fellows or had sex.

Between segments

Grey owls

Some people:

  • Jog and take photographs
  • Practise yoga
  • Have dinner...

A doctor's manual from 16th Century France even advised couples that the best time to conceive was not at the end of a long day's labour but "after the first sleep", when "they have more enjoyment" and "do it better".

Ekirch found that references to the first and second sleep started to disappear during the late 17th Century. This started among the urban upper classes in northern Europe and over the course of the next 200 years filtered down to the rest of Western society.

By the 1920s the idea of a first and second sleep had receded entirely from our social consciousness.

He attributes the initial shift to improvements in street lighting, domestic lighting and a surge in coffee houses - which were sometimes open all night. As the night became a place for legitimate activity and as that activity increased, the length of time people could dedicate to rest dwindled.

When segmented sleep was the norm

  • "He knew this, even in the horror with which he started from his first sleep, and threw up the window to dispel it by the presence of some object, beyond the room, which had not been, as it were, the witness of his dream." Charles Dickens, Barnaby Rudge (1840)
  • "Don Quixote followed nature, and being satisfied with his first sleep, did not solicit more. As for Sancho, he never wanted a second, for the first lasted him from night to morning." Miguel Cervantes, Don Quixote (1615)
  • "And at the wakening of your first sleepe You shall have a hott drinke made, And at the wakening of your next sleepe Your sorrowes will have a slake." Early English ballad, Old Robin of Portingale
  • The Tiv tribe in Nigeria employ the terms "first sleep" and "second sleep" to refer to specific periods of the night

Source: Roger Ekirch

In his new book, Evening's Empire, historian Craig Koslofsky puts forward an account of how this happened.

"Associations with night before the 17th Century were not good," he says. The night was a place populated by people of disrepute - criminals, prostitutes and drunks.

"Even the wealthy, who could afford candlelight, had better things to spend their money on. There was no prestige or social value associated with staying up all night."

That changed in the wake of the Reformation and the counter-Reformation. Protestants and Catholics became accustomed to holding secret services at night, during periods of persecution. If earlier the night had belonged to reprobates, now respectable people became accustomed to exploiting the hours of darkness.

This trend migrated to the social sphere too, but only for those who could afford to live by candlelight. With the advent of street lighting, however, socialising at night began to filter down through the classes.

In 1667, Paris became the first city in the world to light its streets, using wax candles in glass lamps. It was followed by Lille in the same year and Amsterdam two years later, where a much more efficient oil-powered lamp was developed.

Street-lighting in Leipzig in 1702 A small city like Leipzig in central Germany employed 100 men to tend to 700 lamps

London didn't join their ranks until 1684 but by the end of the century, more than 50 of Europe's major towns and cities were lit at night.

Night became fashionable and spending hours lying in bed was considered a waste of time.

"People were becoming increasingly time-conscious and sensitive to efficiency, certainly before the 19th Century," says Roger Ekirch. "But the industrial revolution intensified that attitude by leaps and bounds."

Strong evidence of this shifting attitude is contained in a medical journal from 1829 which urged parents to force their children out of a pattern of first and second sleep.

"If no disease or accident there intervene, they will need no further repose than that obtained in their first sleep, which custom will have caused to terminate by itself just at the usual hour.

"And then, if they turn upon their ear to take a second nap, they will be taught to look upon it as an intemperance not at all redounding to their credit."

Stages of sleep

Every 60-100 minutes we go through a cycle of four stages of sleep

  • Stage 1 is a drowsy, relaxed state between being awake and sleeping - breathing slows, muscles relax, heart rate drops
  • Stage 2 is slightly deeper sleep - you may feel awake and this means that, on many nights, you may be asleep and not know it
  • Stage 3 and Stage 4, or Deep Sleep - it is very hard to wake up from Deep Sleep because this is when there is the lowest amount of activity in your body
  • After Deep Sleep, we go back to Stage 2 for a few minutes, and then enter Dream Sleep - also called REM (rapid eye movement) sleep - which, as its name suggests, is when you dream

In a full sleep cycle, a person goes through all the stages of sleep from one to four, then back down through stages three and two, before entering dream sleep

Source: Gregg Jacobs

Today, most people seem to have adapted quite well to the eight-hour sleep, but Ekirch believes many sleeping problems may have roots in the human body's natural preference for segmented sleep as well as the ubiquity of artificial light.

This could be the root of a condition called sleep maintenance insomnia, where people wake during the night and have trouble getting back to sleep, he suggests.

The condition first appears in literature at the end of the 19th Century, at the same time as accounts of segmented sleep disappear.

"For most of evolution we slept a certain way," says sleep psychologist Gregg Jacobs. "Waking up during the night is part of normal human physiology."

The idea that we must sleep in a consolidated block could be damaging, he says, if it makes people who wake up at night anxious, as this anxiety can itself prohibit sleeps and is likely to seep into waking life too.

Russell Foster, a professor of circadian [body clock] neuroscience at Oxford, shares this point of view.

"Many people wake up at night and panic," he says. "I tell them that what they are experiencing is a throwback to the bi-modal sleep pattern."

But the majority of doctors still fail to acknowledge that a consolidated eight-hour sleep may be unnatural.

More from the Magazine

Margaret Thatcher caught napping, 1990
  • Margaret Thatcher was famously said to get by on four hours sleep a night
  • That put her in a group of just 1% of the population

"Over 30% of the medical problems that doctors are faced with stem directly or indirectly from sleep. But sleep has been ignored in medical training and there are very few centres where sleep is studied," he says.

Jacobs suggests that the waking period between sleeps, when people were forced into periods of rest and relaxation, could have played an important part in the human capacity to regulate stress naturally.

In many historic accounts, Ekirch found that people used the time to meditate on their dreams.

"Today we spend less time doing those things," says Dr Jacobs. "It's not a coincidence that, in modern life, the number of people who report anxiety, stress, depression, alcoholism and drug abuse has gone up."

So the next time you wake up in the middle of the night, think of your pre-industrial ancestors and relax. Lying awake could be good for you.

Craig Koslofsky and Russell Foster appeared on The Forum from the BBC World Service. Listen to the programme here.

Do you sleep in segments? Send us your sleep stories.

 

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  • rate this
    0

    Comment number 321.

    @312. I used to work shifts, day and night rotating and was permanently wrecked - slept more through exhaustion and spent fortnight shutdown asleep!. Now run pub, have a drink, go to bed at mnight but often wake about 4am for about 30 mins and then go off again. Feel better about 8am at w`end when not on school run so I would agree with 8 hours sleep punctuated with a brief woken spell.

  • rate this
    0

    Comment number 320.

    It occurred to me that the start of street lighting coincides with that of the intellectual Enlightenment. Merely a coincidence? An end to the Dark Ages in more than one way, perhaps?

  • rate this
    0

    Comment number 319.

    I don't think that what happened in the 19th century is our 'true sleeping pattern'. What was our sleeping pattern for the 10,000 years before the 19th century? There is growing evidence however that a lag of sleep contributes to many diseases such as diabetes, depression and even heart diseases. So I don't think we sleep too much. By the way an afternoon nap was the norm in the 19th century.

  • rate this
    0

    Comment number 318.

    Thank you Dr. Jacobs, quite a statement of 'over30% of the medical problems that doctos are faced with stem directly from sleep.' ...so very true!
    I have found that better sleep keeps you healthier! I wear Goodnighties for that.

  • rate this
    -3

    Comment number 317.

    307. PulpGrape
    305. Maxone

    Who is the freeholder? Is your property leasehold?
    Is it a purpose built property originally made into two flats? Or a house conversion made into two separate flats?

    When was the property built? Converted?

    This is important re date of Building Regs / Regs re sound proofing if any? And any Noise Nuisance issues that may arise between dwellings and neighbours.

  • rate this
    +2

    Comment number 316.

    'Europe was in darkness until 1677'??

    its called moonlight people!!!!! :P

  • rate this
    -1

    Comment number 315.

    this sounds completely logical... the problem is when you have to get up at 6am to go to work....and your only halfway through your second sleep cycle!!

  • rate this
    +1

    Comment number 314.

    Doctors have different opinions about sleep. But they all agree that getting the right amount of REM sleep (dream sleep) is key for physical and philological health. REM also stimulates the creativity mental processes (Wikipedia). So if you're a top executive be careful when you trade your sleeping hours for overwork and bonuses.

  • rate this
    +1

    Comment number 313.

    310. dyw247
    5 Minutes ago

    Thank you, he/she is refusing to see things from my rather difficult perspective as it is, let alone not actually reading what info I'm giving.

    Anyway on that note I'm off to bed for my 7 hours ahead of a 9 hour working day. Better not close my bedroom door, wouldn't want to wake someone up upstairs whos been in bed since 9pm right?

    Boa noite!

  • rate this
    0

    Comment number 312.

    I work shifts which constantly change. As a result, my body clock gave up the fight a long time ago. I simply sleep when I'm tired, and seem to be mostly nocturnal. Sometimes I'll get considerably less than 4 hours in a night. Other times, I'll sleep for 12 hours solid. Its probably none too healthy, but thats just the way I roll now.

  • rate this
    +1

    Comment number 311.

    @ 309. Maxone
    "It's night time now in the city and I've just seen a fox outside the kitchen window on the grass. Should I be alarmed?"

    Get a grip, Maxone. Don't panic, the fox won't hurt you. You sound as if you're getting over excited. I think I'll go along with dyw247 (post 310) and suggest you try to get some sleep. That will do us all a favour!

  • rate this
    0

    Comment number 310.

    @ 305. Maxone


    In his post # 302, PulpGrape specifically stated: "I own my home". Do please try and keep up - or maybe you are getting tired - I mean, well, it is getting late! Maybe you need 4 hours sleep.

  • rate this
    -3

    Comment number 309.

    304. kit...

    Alarm!

    It's night time now in the city and I've just seen a fox outside the kitchen window on the grass. Should I be alarmed?

    kit, would you be alarmed?

    Rach227, are you alarmed?:-)

  • rate this
    -1

    Comment number 308.

    Exactly my normal. Fought it all my life, am caffeine dependent (makes me smoke) even depressed, at 'real' jobs.
    The perfect speed nap: by the screen, head thoughtfully in hands, nod continually - wake refreshed! Or head-on-arm-over-newspaper may work. Apparently I don't snore.
    Go ahead, laugh. My mother, first generation non-farmer, she's the same.

  • rate this
    -1

    Comment number 307.

    305. Maxone
    5 Minutes ago

    Ok! Who is the Landlord? Private/social? house conversion? Does it have sound proofing?

    ----

    I own my flat on the ground floor, she rents hers privately, just the two flats in the building. Its not like I dont ever hear her walking around heavily on my ceiling everyday but it doesn't bother me. Sound proofing is a cost I'm not willing or wanting to pay for.

  • rate this
    -1

    Comment number 306.

    I'm glad there is so much study being done on sleep! I like to sleep about 8 1/2 hours a night and I have gotten in the habit of telling myself how I want my sleep to be and what I want before letting myself go. If I wake up I just repeat the process. That way I don't feel like it's 'wasted' time and I feel more in charge. Now every night is an adventure.

  • rate this
    -3

    Comment number 305.

    298. PulpGrape
    9 MINUTES AGO
    Comment number 172. Maxone :' Noisy neighbours are a Noise Nuisance & too much noise can cause neighbours sleep deprivation...'
    -----------------------------------------
    ''The point is I am VERY quiet and its not that I keep her awake shes just a light sleeper. Not my problem.'

    Ok! Who is the Landlord? Private/social? house conversion? Does it have sound proofing?

  • rate this
    +2

    Comment number 304.

    @ 301. Maxone

    I agree.You're right about wretched car alarms, however I think you'll find that modern banks have much more sophisticated alarm systems these days, that don't rely on audible warnings.

    But imagine if it was a wolf!?

    If you do have to cry wolf, then please do so quietly as others may be trying to sleep.

  • rate this
    0

    Comment number 303.

    I too can have 8 hours one day & feel tired and yet fresh after 4 another day. Today there are too many unnatural influences on our sleep. The difference it made to me when I changed to decaffeinated coffee & fructose was something I would never have believed. Stress & the pressure to conform with modern life have a massive influence but are difficult to quantify & unfortunately largely ignored.

  • rate this
    -2

    Comment number 302.

    My point hasnt come across. I'm saying I have a neighbour who sleeps a lot longer than me but wakes up at the slightest movement. I am a good neighbour who is very quiet after 10pm. I own my home, I shouldnt feel like a prisoner in solitary confinement. Anyway, I argue that more sleep doesn't necessarily mean you will be better off. She seems to be miserable at the fact I dont go to bed at 9pm :)

 

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