If You Snooze, You Lose

Jim Horne argues we get plenty of sleep:

The apparent desire for more shut-eye, together with oft-repeated assertions that our grandparents slept longer, all too easily leads to the conclusion that we in the west are chronically sleep-deprived. … [Such] Claims … are nothing new – in 1894, the British Medical Journal ran an editorial warning that the "hurry and excitement" of modern life was leading to an epidemic of insomnia.  …

Over the past 40 years, there have been several large studies of how much sleep people actually get, and the findings have consistently shown that healthy adults sleep 7 to 7.5 hours a night. The well-known "fact" that people used to sleep around 9 hours a night is a myth. …

Support for today’s epidemic of sleep debt supposedly comes from laboratory studies using very sensitive tests of sleepiness … in which participants are sent to a quiet, dimly lit bedroom and instructed to "relax, close your eyes and try to go to sleep". These tests … are able to eke out the very last quantum of sleepiness which, under everyday conditions, is largely unnoticeable.

Another line of evidence trotted out for chronic sleep deprivation is that we typically sleep longer on vacation and at weekends, often up to 9 or 10 hours a night. …  We enthusiastically eat and drink well beyond our biological needs. Why shouldn’t it be the same with sleep? Most mammals will sleep for longer than normal if overfed, caged or bored. The three-toed sloth … kept in zoos sleep around 16 hours a day – yet in their natural, wild state they sleep less than 10. …

What of the risk of a sleep shortage causing obesity? Several studies have found a link, … The hazard … only becomes apparent when habitual sleep is below 5 hours a day, … [who] would only gain a kilogram or so of fat per year. … People sleeping more than 9 hours a night are just as likely as short-sleepers to be fat. …

My team recently investigated these questions by giving around 11,000 adults a questionnaire … The people with a sleep deficit were no more likely to experience daytime sleepiness than those without. … We then asked, "If you had an extra hour a day, how would you prefer to spend it?" …  Only a handful of people opted to use their extra hour for sleep.

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  • Horne’s been making that argument for years. You can easily find other experts who take the opposite view. I respect Horne as one of the best sleep researchers – I’ve read his papers – and for taking a stance contrary to not only other sleep researchers but to the general public’s notion that we are living in a sleep-deprived society. It is true, however, that drowsy driving remains an underappreciated public safety problem, and if we make people think about widespread sleep deficit (even if that is dubious) maybe they will take care to avoid driving while sleepy.

  • Horne’s statement applies to America’s “sleep deficit,” but not to the individual sleeper. I, for one, suffer from RLS at night and don’t get the ‘good sleep’ until my eyes have been shut for two hours; eight hours is not adequate for me. Yet my father does fine on less than seven hours of sleep a night, and indeed finds himself unable to stay in bed much longer than six. Our bodies have their own biases.

  • billswift

    “Drowsy driving” is mostly the result of the enforced mental and physical inactivity of driving. I drove back and forth between Washington and Fredericksburg, about an hour each way, and had trouble not dozing off even if I had only been up a few hours after a good night of sleep.

  • the monster from polaris

    billswift has a good point. I find it easier to stay awake on an unfamiliar road than a familiar one. Presumably the unfamiliar road requires more mental activity (and is less boring).

  • Sleep, care to point us to any counter-arguments?

  • I’m unclear after reading Horne’s article what constitutes sleep, as in “healthy adults sleep 7 to 7½ hours a night.” Are they definitely sleeping or are they just in bed? And how much of that time are they in each kind (stage) of sleep?

    I am typically in bed ‘sleeping’ for about 8-10 hours per night but am almost always exhausted when I wake up, feeling more tired than when I went to bed, and I think it’s because I am dreaming so much and have very vivid dreams. On the few nights each year when I don’t recall any dreams, I can wake up and feel refreshed after 5-6 hours of sleep.

  • The people who claim that we are not getting enough sleep tend to be the same people who claim that we are not drinking enough water. These unsupported claims seem to be motivated by the belief that modern society creates artificial living conditions and that the key to a healthy life is to do more things that are “natural”–like sleeping and drinking water.

  • Scott

    I find I’m relatively sleepy if I get up before 10am, regardless of how much sleep I actually got (well, kind of – 12-13 hours would probably do it), while if I get up when my body naturally wants me to, around 11ish, 6 hours is sufficient – though maybe this would not be true for extended periods of time. In general I have to get up when society wants me to, not when I want to.

    Assuming I’m not too far off the bell curve, this sort of reaction could explain why a lot of people feel tired on what is technically enough sleep.

  • I’ve always had problems sleeping, but I also find there’s never enough time in the day to fritter.

  • Here is a description of the evidence that sleepiness causes many traffic accidents. It isn’t conclusive, but looks like it should be taken seriously.

  • billswift

    M Wms what you are writing about are hypnopompic dreams, which occur as you are awakening. If you spend excessive time between when you first wake and getting out of bed you will doze and have extensive hypnopompic dreams. And for some reason I have yet to discover, lying in bed longer like that makes me feel more tired when I finally do get up, and also does not help me stay up later the next night. Recently, I have been training myself to get up when I first wake, even if I’ve only had 6 hours sleep; that seems to work a lot better.

  • Thanks for the info, billswift.

  • Manon de Gaillande

    I can tell most people need only about 7 hours of sleep a night. This is what is expected of students in my type of school, what most get, and they are not sleep-deprived. However, people who need more sleep (I need 9 hours) are severely sleep-deprived, and the damage is much greater than the benefit gotten by people who need less sleep. I suggest fat tails – most people get enough sleep, but the harm to those who don’t is visibly huge.

  • Drowsy driving is hard to pin down. The crash data is horrible, because by the time the officer arrives to fill out the report, the driver is awake (or dead, or in an ambulance). Loud crashing sounds can do that. There is an interaction effect between drowsiness and alcohol, such that two beers and sleep deprivation might work out to four beers, but again try getting good data since most drinking happens at night. When the bars close at 2am, people are not getting much sleepier or drunker than that.

    The evening rush hour is worse for crashes than the morning, but there are many possible explanations. It seems intuitive that in the morning you are both rested and caffeinated, so you have fewer drowsiness-related crashes, but I cannot support that with reliable data. All I can do is recommend an extra cup of coffee around 4pm. And I don’t drink coffee, so that’s out.

    Friday evening rush hour is worse for crashes than the earlier days of the week, but again that is not just drowsiness. I would like to be able to tell a clear story about mounting sleep deprivation, with people becoming increasingly tired as the week wears on and sleep debt builds up, but I would want to see a steady increase in crashes as the week wears on. Running numbers quickly for my state, it seems to follow that trend, but Thursday is not cooperating. It is closer if I drop back a year or two (but not three). I might be able to find a better connection if I spend more than a few minutes, but it will remain shaky because we cannot test for “drowsy” after the fact as easily as “drunk.”

  • Here’s another report on the dangers of driving while tired. It’s about a controlled experiment which avoids the problems Zubon worries about, but doesn’t tell us how much harm results.

    There are plenty of alternatives to coffee for getting caffeine. My favorites are Rocket Chocolate, and Penguin caffeinated mints.