Marks Daily Apple
Serving up health and fitness insights (daily, of course) with a side of irreverence.
23 Feb

Is “8 Uninterrupted Hours a Night” Flawed Conventional Wisdom?

Conventional Wisdom always gets an eyebrow raise from me. I can’t help it. Eventually, I take an honest look at whatever the experts are saying, but skepticism gets first dibs. I’d call it an instinct if it weren’t learned behavior from years of being burned. For example, I once took to task the most pervasive “truth” around: that everyone needs to drink eight glasses of water a day or risk kidney failure, toxin buildup, bladder cancer, and debilitating constipation. It was pretty easy to do.

But it’s not all BS. Smoking is bad for you, for example. See? I can admit when they’re right!

I wonder about the CW position on sleep, though. We generally agree on the recommended duration of sleep. “About eight solid hours” is what you’ll see everywhere, from official governmental health guides to paleo nutrition blogs (I’m sure there’s some niche community out there claiming to have “transcended” sleep, though). I’m not going to argue with around eight hours, but note the use of “solid.” What does it connote?

Unbroken. Monophasic. Constant. Actually, it both connotes and denotes these things. Solid sleep is good sleep, right? And solid sleep means sleeping for about eight hours without waking. If you wake up, you’ve got a problem. Right?

Maybe not.

For most of human history, nighttime meant darkness. Not the blueish whitish permaglow from storefronts, billboards, and headlights enjoyed by modern city-goers. Not the yellow-orange bath radiating down from street lamps on quiet suburban streets, so ubiquitous that you only notice them when they go out. I’m talking about real, permeating darkness. Camping darkness. Small country road with the car lights out darkness. For our ancestors as recently as a couple hundred years ago, this kind of nighttime darkness lasted up to fourteen hours (well, it does today, too, but we mask it with all that lighting and housing). Artificial lighting meant candles and firewood, and those cost (money or time) and don’t really replace daylight (anyone who’s stifled yawns around a campfire knows that) like today’s artificial lighting replaces daylight. People got to bed earlier – because, unless you’re rich enough to burn candles all night, what else are you going to do when it’s dark everywhere but, as Thomas Middleton said, “sleepe, feed, and fart?” – and their sleep was biphasic, or broken up into two four hour segments, with the first beginning about two hours after nightfall.

The first segment of biphasic sleep was called “first sleep” or “deep sleep,” while the second was called “second sleep” or “morning sleep.” Numerous records of these terms persist throughout preindustrial European archival writings, while the concept of two sleeps is common in traditional cultures across the globe. Separating “first sleep” from “second sleep” was an “hour or more” of gentle activity and wakefulness. People generally didn’t spend this time online gaming or surfing the web or trolling the fridge for snacks; instead, they used it to pray, meditate, chat, or to simply just lie there and ruminate on life, the universe, and everything. It was still dark out so they tended to keep it pretty mellow. Sounds nice, huh?

Robert Louis Stevenson liked the idea, too. Sleep historian (awesome-sounding job!) Roger Ekirch writes of Stevenson who, in the fall of 1878, while trekking through the French highlands on foot, alone, made a remarkable discovery. As anyone who backpacks or spends time outdoors will corroborate, Stevenson found himself drifting off to sleep shortly after sunset. He awoke around midnight, smoked a cigarette, and, only after “enjoying an hour’s contemplation,” fell back asleep. That hour, that “one stirring hour” moved him; Stevenson had never before experienced a “more perfect hour.” He had awoken not because of an interloper, a night terror, or any other external actor, but because of what he later described as a “wakeful influence [that] goes abroad over the sleeping hemisphere” and is unknown to “those who dwell in houses.”

Ekirch thinks that the Industrial Revolution, especially the invention and proliferation of cheap electric lighting, forced modern society into its current monophasic sleep pattern by making artificial lighting that really lit up a room available to everyone. People with access to light bulbs could stay awake longer in brightly lit rooms because they were no longer subject to the circadian entrainment of natural light patterns. We’ve gone over light entrainment before. It’s likely worse nowadays, since we’re not just coping with access to ambient lighting, but also loads of interactive consumer electronics (like this laptop I’m using now) blasting circadian-disrupting light directly into our faces. Whereas Owen the London chimney sweep may have flicked on the light bulb and settled down to a good book and a bottle of ale after his shift and gotten to sleep around nine or ten, Jeff the SEO analyst stays up late arguing on Internet message boards with the laptop’s blue light beaming into his very soul. Sound familiar?

It’s likely that societal expectations about sleep structure – that it’s supposed to be eight hours of unbroken, deep, heavy slumber, as everyone knows – are making problems out of what may be normal sleeping patterns. Clinicians are finding that if they can make insomnia patients understand that waking up in the night is actually normal and natural, they feel better about their condition. Because they “perceive interrupted sleep as normal,” they stop stressing over waking and are able to get back to sleep more easily. Some forms of insomnia, in which people wake up in the middle of the night, might not actually be clinical conditions, but rather the manifestation of the natural human sleep cycle trying to assert itself. Insomnia may just be a problem of perception; if you look at your “problem” in a different light as explained by Ekirch, it disappears.

Imagine the possibilities if you could work just such an hour of free waking life into your sleep cycle! You wake up and, instead of exasperatingly checking the time, making a huge huff, and angrily grumbling and tossing and turning in a vain attempt to get back to sleep…

You vigorously and enthusiastically discuss last week’s post with your significant other (whose sleep schedule is also entrained to the biphasic cycle), thus stimulating your mind and supplying a steady rhythmic stimulus to your hip extensors.

You linger in twilight mindspace, that odd world between waking and sleeping that we rarely get to explore, and ponder dreams with a clarity that the 7 AM alarm for work simply doesn’t allow.

You light a candle and quietly read for an hour or so until sleep returns.

Sleep phase entrainment isn’t that easy, though. We do “dwell in houses.” We have by and large been sleeping monophasically for probably our entire lives. Our world is the product of the Industrial Revolution, for good and for bad, and so we must work with that reality. Candles at night will help, as will camping trips when possible, and limiting excessive late night computer exposure (or installing the ever-popular f.lux) is always a good move. You can try getting outdoor light exposure during the daytime – maybe go for that hike, that walk at lunch, or that outdoor workout.

But we’ve gone over that stuff before. It’s good, but it’s been done. In light of this new (old?) information about biphasic sleep patterns, perhaps the most effective change we can make is in our perception of sleep and waking. Make like those insomnia patients and change the way you think about waking up during the night. Don’t stress and fret; welcome it. Maybe, instead of assuming that this is all a horrible mistake and your cortisol is going to spike and you’re going to crave extra sugar in your coffee in the morning next time you wake up in the middle of the night, welcome it. Ever notice how you’re not all bleary eyed and zombie-like when you wake up at 2 AM like you are at 7 AM with the alarm blaring?

I’m thinking we should all explore why that is.

What are your experiences with waking up in the middle of the night? Do you need a solid block of sleep each night, or do you just assume that’s the case? After reading today’s post, see if your next mid-night wakeup feels different.

You want comments? We got comments:

Imagine you’re George Clooney. Take a moment to admire your grooming and wit. Okay, now imagine someone walks up to you and asks, “What’s your name?” You say, “I’m George Clooney.” Or maybe you say, “I’m the Clooninator!” You don’t say “I’m George of George Clooney Sells Movies Blog” and you certainly don’t say, “I’m Clooney Weight Loss Plan”. So while spam is technically meat, it ain’t anywhere near Primal. Please nickname yourself something your friends would call you.

  1. Does anyone have any thoughts to helping with night time hypoglycemia and night sweats? Despite the excellent post from Mark, when you know your adrenals are shot and are being woken up by blood sugar drops/adrenaline release/vivid dreams, it’s hard to feel ‘serene’ during the waking hours.

    This is despite a low carb diet, around 50-60g a day, mainly from squash, carrots and beets with plenty of protein and fat split into regular meals. Digestion doesn’t handle heavier starch at all.

    Matt wrote on February 24th, 2011
    • Stop stressing your adrenals. Stressors could include: extended low-carb, overexercising, fasting, caffeine, alcohol, job you hate. I healed my adrenals and stopped the nighttime adrenal release by taking adaptogens, eating more carbs, and quitting coffee/alcohol and exercise for at least 6 months. I also quit my job and eventually got a new one. It worked!

      Gazelle wrote on February 24th, 2011
      • @Gazelle. Which adaptogens worked for you? I am currently reducing my stress load as well but my adrenals need that little extra help. I am at university though, and don’t want to quit that. I plan on taking a 6-12 month vacation when I graduate in order to get my adrenals completely healed.

        Kitty wrote on February 24th, 2011
        • I took something called AdreCor which has C and B vitamins and a few amino acids plus rhodiola rosea extract.

          Gazelle wrote on February 24th, 2011
      • Thanks Gazelle,

        The more carbs I add even at these levels results in a worsening of hypoglycemia.

        So I have a choice between low carb general adrenaline stress or added carb hypoglycemic stress. A nice choice to be faced with!

        But your probably right, it ultimately all comes down the adrenals I imagine.

        Matt wrote on February 24th, 2011
  2. For those with iPhones, there is an app called ‘Sleep Cycle’ which when you place on your mattress throughout the night, it monitors your sleep cycles and depth of sleep using the accelerometer in your iPhone based on your body movements. It’s pretty accurate, and can be a good way to measure how much deep sleep you have, how long your awake for, etc. I think it’s worth the 99c/59p…
    The only thing is that I don’t like having a phone next to my head all night every night, but that’s up to the individual as to whether that bothers them. Quite interesting to see what I’m up to during the night…

    April Foster wrote on February 24th, 2011
  3. I’ve found lately that I’ll drift off for a little less than an hour when my wife goes to sleep- then I wake and stay up for a few hours before going back to sleep. Usually use the time to write.

    Didn’t think I was doing something right until now though.

    John W wrote on February 24th, 2011
  4. Do Mark wake up at night?

    C2H5OH wrote on February 24th, 2011
  5. Awesome post, Mark.

    Had the strangest experience the other day, woke up at 2AM feeling completely rested. Just assumed it was time to go to work, so got up and put the kettle on, only to glance at my watch and see the time.

    thought it was bizarre at the time but it makes more sense given the context presented here.

    George Cathcart wrote on February 24th, 2011
  6. Thanks Mark. I was wondering why I’m waiking up in the middle of the night and I was getting upset about that. That post explains a lot. Thank you again.

    Assen wrote on February 24th, 2011
  7. As simple as it sounds, I think we are properly rested when we wake up when we feel like it.

    If you eliminate alarm clocks and strict schedules, people will be properly rested.

    While we sometimes struggle to get to sleep on time, once asleep it is out of our hands essentially, and our body allows us to wake up when it’s good and ready.

    I used to set my alarm clock for 5:30 AM and then hit snooze until 6:15 or even 6:30. Lately, I have been leaving my alarm off entirely (my wife’s alarm goes off at 7 to get the kids off to school). The thought process is that I will try to wake up naturally, and in a worst case scenario I’ll wake up with my wife and then deal with being late to work.

    So far, 3 days in a row, I have woken up naturally around 6:15 (give or take) and feel much more refreshed.

    Helj wrote on February 24th, 2011
    • I’ve been thinking about getting one of those natural lighting alarm clocks that will gradually brighten instead of a blaring alarm going off.

      Of course that’s assuming (and we know where that gets us) that a gradual awakening is superior to an abrupt awakening, and I’m not sure it is if it isn’t natural.

      Pat wrote on February 24th, 2011
  8. Polyphasic sleep is better in my opinion. Tim Ferris speaks a lot about this in the 4-Hour Body book. I prefer 6 hours during the night and a 20-30 min nap in the afternoon myself.

    George wrote on February 24th, 2011
    • Well, if by polyphasic you mean 6-7 hours at night and then naps in the day, then I agree. Naps are great, and offset that need for extra sleep at night.

      As for 4 hours, then an hour awake, then 3 more hours … I wouldn’t be able to speak much to that because more often than not when left in quiet (i.e. no kids waking up with bad dreams and wife not elbowing me in the face when she rolls over) I tend to sleep through the night soundly.

      Helj wrote on February 24th, 2011
  9. Moon light?

    Sean wrote on February 24th, 2011
  10. Wow. Mind blowing.

    I used to do this when I was in high school and I’d come home really tired, lie down and take a nap for an hour or two. Then I’d wake up, have dinner and go about my business and go to “bed-bed” only a bit later than usual and wake up refreshed in the morning.

    My brother used to tell me I was ruining my sleep patterns; fortunately when I mentioned it to my doctor (a very laid back individual) he told me that if it worked, great. No reason to stress about it.

    Pat wrote on February 24th, 2011
  11. Off topic but what is your opinion on chickpea flour?

    Sean wrote on February 24th, 2011
  12. My natural sleep pattern is to sleep for 4 hours, be awake for 2-3 hours, sleep for 2-3 and then a catnap in the afternoon. Worked great when I was in college, not so much in the world I live in right now.

    Runnergal wrote on February 24th, 2011
  13. I try to be in bed by 11 each night and tend to wake up around 4 am each morning, but immediately try to go back to sleep since I’m often up between 5:30-6:00 to get ready for work.

    Dave P. wrote on February 24th, 2011
  14. Oh, I forgot to my main point (clever girl I am), which is that the ‘Sleep Cycle’ app also works by waking you within the half hour (or you can change the time frame) before your set alarm time by choosing to gently wake you during your lightest sleep, rather than a loud alarm going off and scaring the shit out of you when you were in the middle of a nice deep sleep.
    Gee, I sound like I sell this thing…

    April Foster wrote on February 24th, 2011
  15. Very interesting – both the blog post and the comments about everyone’s sleep patterns. The times I feel the most refreshed and alert in the morning are the times I’ve slept solid through the whole night (8 hours is best for me in summer and at least 9 hours is best for me in winter). I generally feel extra groggy and tired in the morning when I’ve woken at 2, 3 or 4.

    Lynn wrote on February 24th, 2011
  16. Wow, nature has already created this first and second sleep for me.

    I am a breast feeding mother. I go to bed. Baby wakes up, I feed him for an hour, we go back to sleep. I can imagine that has been the pattern for many mothers since the beginning of time!

    I have especially always enjoyed that hour of feeding my baby in the middle of the night. Everything is quiet, no body is calling us, it is just peaceful bonding time.

    Now I do admit, that sometimes that sleep is also broken up by a second or even third feeding, my three year old waking up with a nightmare, a bout of teething that makes everyone a bit tired…

    However, it seems like once again nature has already created for us the “perfect plan!”

    Emily wrote on February 24th, 2011
  17. I rarely get 8 hours uninterrupted. Between the sleep apnea early on in my life and the babies my life consisted of many tiny naps strung together. Thanks to Primal I sleep deeply now. What I find is that I can sleep less because I am getting quality sleep for the first time in my life. I feel more refreshed and energized on less than 8 as long as it’s one solid chunk of time. If I’m woken in the middle somewhere, it just never seems as energizing.

    Melissa Fritcher wrote on February 24th, 2011
  18. I almost never get a “solid” 8 hours.I’ve actually come to enjoy my quiet time in the middle of the night as the only time when I can really reflect on life. The rest of the day is too busy or noisy. I’ve started going to bed earlier, just to allow for that extra hour, and I don’t feel like I’m lacking any sleep because of it.

    Robin wrote on February 24th, 2011
  19. Hi everyone,

    Just thought you might find this post from Ted about sleep, which entirely backs your argument, interesting.

    Sorry if anyone else has posted this

    Rebecca x

    rebecca wrote on February 24th, 2011
  20. This argument from Ted by Jessa Gamble totally supports your argument.



    rebecca wrote on February 24th, 2011
  21. Interrupted sleep may have served as a survival mechanism – think old school sentry duty.

    But for many, sleep is their only viable escape, a luxury and necessity at the same time. Given a choice, I’d rather sleep ~8-9 hours uninterrupted in deep, deep sleep.

    Regardless of number of hours, what I want is to wake invigorated, not groggy or tired.

    Morrigan wrote on February 24th, 2011
  22. In college, when I had my own apartment, my friends thought I was nuts when i told them that I’d come home from work/class, go to sleep for a few hours, wake up around 10 and study/eat/whatever until 1 or 2, and then go back to bed until I had to get up for work (5AM) or class (6AM). It was great, got me through college, and allowed me to be really productive when others would be sleeping.

    Perhaps my night owl tendencies, besides all the tech (just installed f.lux), come from having bypassed that first phase of sleep, and then making up for it by shifting the phases til later. When I do that, I’m optimal at 2AM-10AM, with a little wake up around 6 or 7.

    Also, it changes with the landscape. In Oregon, it was asleep at 2-3AM for 8 hours. Here in Washington, it’s 12-8AM, with a brief alert period sometime during the night (I don’t have a clock that glows or anything).

    Tanya wrote on February 25th, 2011
  23. BTW, Mark, this article was excellent. Also, I wonder if, after the Industrial Revolution, the period of time in the middle of the night was not mentioned or encouraged because it isn’t strictly “productive” time. Our industrial culture doesn’t really promote time to reflect and meditate (and even our media that advocates meditation will tell us to schedule it for a certain time period, which isn’t usually at night).

    Tanya wrote on February 25th, 2011
  24. I often wake in the night and stress about trying to get back to sleep. After reading this I am going to try and embrace it when it happens next – can’t wait!

    Thanks :-)

    Bridget wrote on February 25th, 2011
  25. Unfortunately I wake up all night long. I have been using a CPAP machine for about two years now and still haven’t gotten used to it. I fidget all night, adjusting and readjusting until I finally get up in the morning. I am hoping – as I advance into my primal life style – that weight loss and a lack of food related allergies will help alleviate some of my nighttime breathing problems making it easier to sleep. I would be happy with about four hours of uninterrupted sleep!

    Skeeter wrote on February 25th, 2011
  26. I’m another mother who never “sleeps through the night.” In fact, prolactin (the breastfeeding hormone) makes you sleep more lightly and arouse more easily. Handy!

    People ask me, as if it’s some kind of contest, whether my 10-month-old sleeps through the night. He doesn’t, but I really don’t mind. As long as he’s only up a couple of times and goes back to sleep easily, I barely even remember it. I sincerely doubt primal mothers sleep-trained their babies! It’s so much nicer to get a quick check-in on the baby in the middle of the night, let him get a snack (babies have tiny stomachs, after all), and go back to sleep afterward.

    I am learning so much about instinct and primal habits from my son. From hating shoes, to squatting down to play, to preferring meat to any other food (after good old mama milk of course), you don’t get much more primal than a baby!

    Sheila wrote on February 25th, 2011
    • I know! That got to driving me nuts with my second child, the whole notion that I was supposed to be “teaching” her to sleep. I was like, “she has no problem sleeping, people–what’s to teach?” We have such a hard time just letting people be people at all stages of their lives. Infants are not miniature adults!

      Dana wrote on February 25th, 2011
  27. My lady, (Barbeygirl) and I have been discussing this subject quite a bit lately. We are both in bed by 9 and both awake between 1 and 3 for about an hour. Thanks Mark, for clearing this up for us. From now on, I’ll grab a non-fiction book and read until I’m ready to go back to sleep.

    Michael wrote on February 25th, 2011
  28. This article makes me feel much better. Since my high school days(I am now 61)I have only slept in 2 to 3 hour intervals. Everyone in my family thinks I’m a little weird for that but it was always just normal to me. Thanks for posting this article. It sheds new light on what’s normal for each person and what everyone has been told is normal or necessary. Grok on…..Twigs!!!!

    Jane wrote on February 25th, 2011
  29. While doing extended river rafting trips that might be anywhere from 3 nights to 14 consecutive nights camping and while on a 5 week bike tour where I was camping 6 out of 7 nights per week, the typical nights sleep was very similar to what you describe in the post. It only makes sense that primal man would get up in the night – that would be a survival trait that most likely was passed down genetically. I have seen the damage done by sleeping pills and to me, taking an approach to sleeping like you articulated makes perfect sense.

    Shasta wrote on February 26th, 2011
  30. Carthusian monks sleep 4 hrs then wake for prayers (2-3 hrs) then sleep again for 3 hrs. They’ve been doing this for 900+ years and seems to work for them as they generally live long and healthily. I was a novice with them and that midnight time was most contemplative.

    Marc wrote on February 26th, 2011
  31. Something that struck me is, if people did wake up in the middle of the night for a couple of hours back when they didn’t have electricity, they still in total managed to get 8 or so hours of sleep, since they were in bed for much longer.
    Nowadays, when people are in bed for a total of 8 hours (on a good day), and they lose 2 hours of sleep at night, they’re then down to only 6 hours of sleep…

    The Primalist wrote on February 26th, 2011
    • This true, and my main problem. With all of this technology and so much work to do, it is hard to go straight to bed when it gets dark. Especially with children to keep you busy all day and then trying to catch up with everything else once they go to bed. I usually don’t get to bed until about 11pm, and then have to get up before 7pm to get them ready for school etc. and start the day. That is eight hours. But because I wake up for a couple of hours during this time, I’m not getting a lot of sleep.

      Kitty wrote on February 26th, 2011
      • Kitty, try meditation before bed. It is a great intermediary between all that other stuff and sleep. Also do it through the day, 10 minutes or more, and you will find that it is very restful and good for ya.

        Rocco wrote on February 27th, 2011
        • Thanks Rocco. I used to meditate, but life just got a bit out of control for a while. Just need to get back into it. Starting today :)

          Kitty wrote on February 27th, 2011
  32. The period between the two sleep phases presumably was (and still could be) a good time for procreation.

    GWhitney wrote on February 26th, 2011
    • I was beginning to wonder when someone would notice that….All these comments about it being a good time for a chat or some meditation…

      Kitty wrote on February 26th, 2011

Leave a Reply

If you'd like to add an avatar to all of your comments click here!

© 2016 Mark's Daily Apple

Subscribe to the Newsletter and Get a Free Copy
of Mark Sisson's Fitness eBook and more!