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.

About the Author

Mark Sisson is the founder of Mark’s Daily Apple, godfather to the Primal food and lifestyle movement, and the New York Times bestselling author of The Keto Reset Diet. His latest book is Keto for Life, where he discusses how he combines the keto diet with a Primal lifestyle for optimal health and longevity. Mark is the author of numerous other books as well, including The Primal Blueprint, which was credited with turbocharging the growth of the primal/paleo movement back in 2009. After spending three decades researching and educating folks on why food is the key component to achieving and maintaining optimal wellness, Mark launched Primal Kitchen, a real-food company that creates Primal/paleo, keto, and Whole30-friendly kitchen staples.

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

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  1. I heard an interview on public radio a few months ago where the lady talked about first and second sleep and neighbors visiting over the fence between sleeps back 100 years ago and more.

    That interview and listening to DeVany’s thoughts on the topic have informed my opinion on the matter. I no longer get too worried when I wake up at 3 or 4 a.m. and can’t get back to sleep.

    1. Deepak Chopra put out a book on this called “Restful Sleep”

      I read it and was intrigued by his suggestion of natural sleep cycles. The operational side of his suggestions are, “Go to sleep early, get up early, use an alarm clock only if you must.” I sleep in the same cycles. All programmers know the best coding is done around 1AM.

  2. I appreciate this post. I have never slept through the night, even as a child. And I was concerned about my cortisol levels. I usually feel rested when I get up in the morning, so I haven’t been too worried. This post puts me at ease. Thank you!

  3. Boils down to goals, right? If you want to up your productivity, then limiting sleep to a sustainable minimum is the thing to do. But if you’ve got the time (not to mention the metabolic derrangement), then sleeping in as often as possible is probably the right choice. Clearly, sleeping quantity and quality can be improved just by plugging in the formula that you’ve laid out before.

    1. Personally, I like to meet with my best friend once a week and enjoy a fine Cuban cigar on his balcony, no matter what weather conditions prevail. It’s pretty cold right now in Switzerland, but we always enjoy this man-time fraught with inspiring conversations.

      1. It’s just like a tiny, portable, tasty campfire. Stimulating to conversation, most certainly.

        Switzerland doesn’t have a ban on the good stuff like we do here. I envy you.

        1. I’m so glad I’m not the only one, this has become my ritual before I go to bed at night. Usually I smoke my pipe because I can get a bag of tobacco for much cheaper, but let me tell you, if I could afford it, I’d light me up a nice stoagie every night if I could. 😉

      2. Ha ha, excellent stuff. I enjoy a smoke from time to time(100% ‘natural’ American Spiriti tobacco though, meaning no pesticides, chems and so on). I might find a buddy to enjoy a cigar with too! Tobbacco was a major focal point of Indigenous American culture. That’s doesn’t mean people should start chaining it all day though.

  4. It’s funny i’m reading a post about this because for the past few months, I’ve been waking up around 3:30 exactly finding myself unable to go back to sleep for about an hour so. Within that hour I’ve been reading (almost always nonfiction) and finding I’m getting a lot out of my reading time. I’m able to retain more (so it seems) and everything just clicks. But after that hour is up, I’m out again!

    1. Fascinating. When are you going to sleep?

      I tend to crash around midnight and get up at 8:30-9. I have noticed, however, that going to bed earlier makes me wake up in the night.

      1. I know you didn’t ask me, but I get in bed (with wifey!) at around 9 p.m. each night and I’m asleep by 10. Sporadically, I will wake up very early. Sometimes I get back to sleep; other times I don’t. I’ve been up since 4:30 a.m. today. Feeling fine.

    2. I’ve been waking up at 3:30 also! Unfortunately half the time I don’t go back to sleep; maybe because I think too much about how I really need to get back to sleep. Now I’ll just go with it and catch up on some reading, that usually seems to put me out!

  5. LOL – Mark you must have a very understanding wife!

    I travel to different time zones every now and again and I find 4 hour sleeps seem to most comfortable when I’m not fitting myself into a set time frame. I quite like being awake for an hour or two in the middle of the night when I can manage it. I’m trying to rearrange my work so I can get a lie in as well.

  6. This article is some good food for thought.

    In the past, if I woke up in the middle of the night, I’d huff, buff, bitch, moan, and then try to kill the time until I feel back to sleep. Then when I finally woke up from my “second sleep”, I’d feel tired and cranky.

    Maybe if I perceive this as a natural occurence rather than a hindrance, I’d quit worrying so much and get a better night’s sleep despite the midnight interruption.

    1. I am 100% with you on that! I will alter my attitude about “damn it’s 3am” wake ups and start seeing it as a blessing…

  7. My retired parents have a newspaper route for extra income. Although I like that they get regular physical activity from the route, I’ve always been concerned about their irregular sleep habits. They go to bed around 8-9 PM, get up around 2 AM, fold/deliver papers until 4-5 AM, and go back to bed until 9-10 AM. They don’t seem to be any worse for the wear, and this post puts my mind at ease. Stupid CW.

  8. There was a study some time ago, looking at sleep patterns in third world and “primitive” societies. The researchers found just this first and second sleep pattern, and called the wakeful period the “sentinel period.” They postulated that there was an evolutionary advantage in having a certain number of individuals awake at various times during the night, in a calm but alert state, to monitor for dangers from the dark. They concluded that it was hard-wired in, very Primal… a natural pattern of sleep that simply doesn’t fit in with our pace of life now.
    So I would venture to guess that the CW promoting a “solid eight hours” is to sleep what the CW promoting “many servings of whole grains and legumes” is to digestion. Fits nicely. Thanks, Mark!

    1. Great post Mark. Same thing applies to eating; two meals a day was common in the middle ages. Wild animals also sleep this way. Kelly’s comment really hits the nail on the head. It is an evolutionary adaptation, just like everything else we do and CW tries to surpress with “regularity”.

      I have synchronized with my wife’s sleep now. We are both up and down and go into the living room to have pleasant talks.

    2. I like the sentinal theory. I’ve often thought that teenagers’ propensity to stay up late might have been very useful in “the old days” (caves, camps or castles) because they could keep watch while they talked to each other. And their sleeping in the daytime while others are awake is seen as sloth in modern days by too many people, but I think as long as they get sleep, it shouldn’t matter so much what time it is.

    3. I was just about to say this! The same way the members of a squad in the military must keep watch throughout the night, so must our primal ancestors.
      Just the idea of a bunch of primal humans sleeping in a pile of 15-30 shortly after the sun goes down and waking up right after it comes back up always did seem a little strange to me. There are plenty of things that go bump in the night that you’d want to keep an eye on, and plenty of nocturnal predators that could ravage an unsuspecting group like that if no one was awake to warn them. It also gives a primal explanation to the reason why teenagers do not produce melatonin to put them to sleep until later in the night, putting their bedtime at 11-12am, while from the sounds of it other people here wake up from a range of 1 to 4:30am. This article made a lot of sense to me and cleared up a lot of holes.

  9. A few times a year I’ll go through several days of waking up at 3 or 4 am. This has been happening since high school. So now I know to expect it and I usually spend that time doing some form of art.

    Last September I had four paintings and a blog in the works when my husband came down stairs around 7 am.

  10. First, LOL at “Owen the Chimney Sweep.”

    All I know is that the more interrupted my sleep, the better my chances for a migraine and living in a city (even with blackout shades) isn’t helping.

  11. wow, That was a huge load off. I always wake up at around 2 am and have been attributing it to some cortisol, But I do feel pretty awake and sometimes when the moon is out I want to sit and stare at it instead of go back to sleep. Thanks for that mark.

  12. Ever since we moved 8 years ago from the big city to the mountains, our former sleep problems have disappeared. Thinking about it, I’d have to attribute it to the complete absence of street lights up here. Sleeping in complete darkness is wonderfully restful.

    1. Ailu moving to the mountains and having better sleep is also attributed to being grounded. So kudos to you!

  13. Well, as far as I can remember, I never slept in one solid block. I always have several sleep cycles and I certainly never thought much or even stressed about it. Lucky me.

  14. This may explain my habit of falling asleep around 11:30pm, waking up around 3:30 or 4, laying there for awhile, then falling back asleep for a couple of hours. Fascinating.

  15. Interesting. I remember watching a documentary of two western guys living with a primitive tribe somewhere (maybe New Guinea, can’t remember). One of the westerners biggest complaints was that the people were talking all night! A similar complaint comes from the author of “Don’t Sleep There are Snakes”, who was trying to translate the language of an isolated Amazonian tribe. These examples suggest that hunter gatherers were not necessarily getting a solid 8 hours!

  16. There was a show on the History Channel a few weeks ago about why we’re afraid of the dark; they spent a few minutes talking about biphasic sleep. Nothing beyond what has been mentioned here already, just that people used to go to sleep shortly after nightfall, then woke up around midnight, sometimes traveled to a neighbors house to socialize for a little while, then went back to sleep and woke up around dawn.

  17. I feel best when I get 7-8 hours of sleep a night. I normally sleep straight through pretty solid and wake up on my own.

    Sometimes I do wake up in the middle of the night for the bathroom, I just do so and make sure I don’t turn any lights on. Then im back asleep before I know it.

  18. What about the moon? I do a lot of camping, and when the moon is even partly full, that sucker is bright. I’ve done a lot of hiking by full moon, and there’s plenty of light. For most of the night. I just can’t buy the “county road dark” argument. Sorry.


    1. I agree. It doesn’t seem likely that Grok and Grokina got too many nights of absolute darkness. Besides the moon, there may have been a campfire for warmth and protection. So I am skeptical of gurus who say you need total darkness to sleep well (which Mark does not in the post.)

    2. Maybe they were using the full moon for hunting… or fishing. Tides with full moon always bring in more crabs, etc.

  19. I’ve found that when I wake up in the middle of the night, my mind is clear and alert. I usually have very real and profound thoughts and ideas. The problem is that I forget those thoughts and ideas when I awake at 7am with a fuzzy and tired mind.

    1. Perhaps you should keep a notebook by your bed and write down your thoughts.

  20. Outside of illness I can’t remember ever going to bed at a reasonable hour and then sleeping straight through until morning. I don’t know that I’m awake for an hour straight during that time, but then again I’ve don’t generally obsessively check the clock. Glad to hear this is apparently the normal order of things.

  21. Thanks Mark, I thought there was something wrong with me because I wake up at 3-4 each morning, take a whiz, walk around a bit, get a drink of water, then go back to sleep till 6-7. Maybe I?m not weird after all.

  22. As usual, this post is right on. Eight hours of sleep leaves me tired, stiff and sore. I naturally wake around 4 am. I should really follow Mark’s advice. But…

    I don’t like being awake in the middle of the night. The various things that people traditionally did in the past sound great on paper. But not in practice for me. Sadly, I do not have the option Mark suggests from last week’s post. My eyesight isn’t good enough to read by candle light.

    1. Nor is mine. F.lux and a laptop works great for me though. The f.lux cuts most of the blue light from my laptop while making it bright enough that I can still read by it without turning any lights on. It’s like reading by very bright candle light; I usually go back to sleep in less than an hour.

      Side question: Can you install f.lux on an Ipad?

      1. Yeah, I was hoping there was an f.lux app for my android as that’s how I read when I wake up in the middle of the night. Can’t turn a light on to read a book, but the using the phone does heart my eyes after a while, even with it set to night mode (black screen, white writing) and the brightness turned down.

  23. I’d been thinking of gradually moving towards a more biphasic sleep schedule for a while and this post offered some really interesting points to consider in favor of making the switch. I think that for now if I wake up in the middle of the night, I’ll take advantage of it, light a candle and read from now on.

  24. If I sleep all through the night I NEVER feel as rested as when I go to bed when camping. When I camp I always seem to wake up around 1am and fall asleep again around 1:45 to 2:30am. I usually grab a handful of trail mix and munch on that outside the tent until I’m tired again.
    There are times when I camp and I don’t wake up in the middle of the night, but usually alcohol is to blame for that.

    I really enjoy the middle of the night arousal though, since that’s generally when I get my creative juices pumping. A good 70% of my poetry was written after waking up in the middle of the night.
    There might also be a relationship to the middle of the night wakefulness and staying up until that hour. I know if I stay awake until 1 or 2 am I’m in a clairvoyant state-of-mind where work seems to do itself.

  25. Thanks, Mark. I feel better after reading this article. Have started stressing when waking between 2:30 and 3:30, then staying awake a couple hours. Definitely feel better at 2:30am than 7am when I wake up starving. Will try not stressing and maybe read for an hour. Thanks, again.

  26. The funny thing is conventional wisdom, common sense, etc, none of those are science based. They are really just the sum total off all the prejudices societies and families have built up over the years.

    As Carl Saga wrote: “I try not to think with my gut. If I’m serious about understanding the world, thinking with anything besides my brain, as tempting as that might be, is likely to get me into trouble.”

    1. Sagan! not saga! augh 🙂

      the same applies to studies with poor control groups. They are tempting, but when better experiments or studies can’t replicate results, we have to let them go.

  27. I sleep almost exactly seven hours in the summer when it’s light out for a longer period of time. In the winter I need nine or ten, which can be a problem sometimes, but I’ve stopped fighting it. Sometimes it means being awake for a whole 40 minutes after I finally get home at the end of the day, but I work around it.

    When I am stressed I wake up in the middle of the night and cannot get back to sleep. I’ve tried to embrace it (read, do fun projects etc) but I can’t seem to get away from being exhausted the next morning if I have hours of wakefulness in the night. Instead of waking up on my own before my alarm (set as a safety net) feeling refreshed, I am jolted awake by my alarm, and feel groggy and shaky.

    I am going to try to change my thinking about it and see if that makes a difference. Maybe it will kick the grogginess aside. 🙂

    1. Much like me, although I got worse recently – shaky, cold, breathless… A new doctor recommended an endocrinologist who has requested tests for hypoglycemia, hyperinsulinemia and hypercortisolemia – stress related hormone imbalance.

  28. This is my central issue right now: my high-carb lifestyle caused me to have night terrors, hypoglycemia around 3am that caused my adrenals to hit me with adrenaline, and sometimes even full-blown panic attacks. Starting paleo, my hypoglycemia has gotten much worse, and the waking in the night is more agitated. Someone told me that if you’re stuck in “survival mode” where your adrenals are still trying to “save you” by releasing sugar into the bloodstream, it’ll be much harder for your body to switch over to burning fat for fuel. Anybody else have a terrible time with hypoglycemia / panic when going paleo? (And yes, I was hypoglycemic and prone to panic attacks eating grains & high carbs, too. Please tell me this is just an adjustment period.)

    1. Yes. Waking up for several hours in the middle of the night with pounding heart is not normal, IMHO.

      Biphasic sleep makes sense to me for humans who did not have electricity. Going to sleep when it gets dark and waking for a few hours later, then sleeping again, makes sense when it’s very dark and your waking life is based around this schedule. Modern man going to sleep at 11 at night and then being up for 3 hours at 2am before having to be up again for work at 6 or 7 doesn’t seem healthy. That’s about 4 hours of sleep. Does anyone here feel refreshed after getting only 4 hours of sleep every night?

      I sleep pretty soundly from around 10 or 11 to 6 or 7 but suffered from severe insomnia when I was low-carb and my adrenals were shot. Up for at least 3 hours every night starting at 2am and exhausted and miserable. I had to heal my adrenals (cortisol levels were pretty much flat-lined) by eating more carbs, and avoiding things like caffeine, overexercising and fasting, etc. All those things that stress your adrenals.

      Be careful.

    2. I was having problems with panic while eating high carb (mostly junky carbs). It might be easy for normal people to switch to low carb, but for me it was hard and took at least 6 months of adjustment. I had sleep issues, hot flashes, heart palpitation, anxiety, etc. Now that I’m adjusted, I’m way more relaxed and feel mentally much better and tougher. I can for long periods without eating and never feel panicky.

      1. So it sounds like it’s an adjustment that takes some time. But there’s hope?

    3. Me too! Lately I have been waking up from super stressful dreams where I am screaming angry. When I wake up my heart is racing, I have a terrible headache, and other symptoms of stress. I have gone back on Metformin under the theory that my liver is dumping glycogen in the middle of the night causing my insulin to surge and than crash. (I am very mildly pre-diabetic, and have hyperinsulinemia, so my doctors are pushing the Metformin.)

    4. Try eating a bowl of cottage cheese before bed. It helps with hypoglycemia for some. It helps me when I need it.

  29. Thanks for this post Mark. I have been having trouble sleeping through the night for almost 11 years now. What a relief to know it is OK. I am going to have to change my mindset on this. I am sure it will help.

  30. Mark,

    Although back before the cultural revolution we may have been biphasic sleepers, there has been a significant amount of time that has passed. The real question is has or will the human body adapt to monophasic sleep? As you stated many people do suffer from what they call insomnia. But the majority of our population does not. Can we attest this a new sleep pattern, nutrition, pharmaceutical companies (all the crap they say we need) or just a person that has not fully adapted to a new pattern? Appreciate the post and something to think about.

    1. First off, there’s a couple of estimates that around 30% of people suffer from insomnia. Those are from pretty mainstream sources, too. That’s not counting people who just wake up and take a piss, get some water, feel a bit alert, but get back to sleep easily. Also, I’ve noticed that if I stay up later (after midnight, say), or if I’m very tired (say if I’ve gotten 4 or less hours the night before), I tend to more or less sleep though the night. Otherwise, I’ll wake up after 4 hours, very reliably. So, if you account for the people who do report sleep problems, combine that with the amount who don’t get enough sleep, and therefore sleep through the night, and the people who just don’t have a problem getting back to bed… You’re most likely approaching the majority of the population. The remainder would probably still wake up if they were going to bed soon after dark.

  31. I nurse my baby on-off all night long. I definitely have my brightest ideas during those wee hours.

    But I got to say, I’d love to sleep more than 2 hours in a row! 😛

  32. I love the “steady rhythmic stimulus” hint there!

    BTW – that is an absolute great observation when you mention “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?” because I HAVE noticed that.

    Thanks Mark. This post may actually let me rest easy now (pun intended!).


    1. Me too! Why is that? It almost feels
      like the second phase has caused some
      inflammation doesn’t it?
      Mark, you are on to something that needs clarification. 🙂

  33. The only time I sleep through the night is when I have absolutely exhausted myself. Normally I wake up at least once between 3:30 and 4:30. If I go to bed super early (before 8pm) I also wake up around midnight for awhile. Always just thought of it as normal for me.

    Here is a tidbit that I have always thought strange… for those of us that have cats, have you ever noticed that they come in during that light sleep period even though you don’t make a sound? My cats always knew, no matter what time I woke up, that I was waking up and at that point they would come in and see me. I don’t know if they can hear me moving around more or my breathing changes but all of my cats did this in some way shape or form…. the weird thing is that even if the time I wake up changes they still figure it out.

    Sorry for the off topic but I have always wondered and sharing my wonderment is something I like to do!

    1. How do you know they are not coming in and seeing you when you are asleep? LOL – I have cats too – mine seem to party all night while I’m dozing off.

      They do seem to have some sort of sixth sense though.

    2. Yes! Our cats know the *instant* I wake up. Doesn’t matter if I don’t move at all, as soon as I open my eyes, they come into the room. I have no idea how they do it!

      1. Mine do that too! The very second my eyes open, one of my cats is in my face, demanding attention and breakfast. I don’t know how they do it, Maybe I move around a lot right before I wake up?

  34. I just spent a week camping in the Sonoran Desert and the moon made the entire night bright as heck. It was NOT dark at night for a week.

  35. I have always been a big believer in 7-8hrs of uninterrupted sleep and get perplexed when I’m up at 1 or 2am (besides the newborn being hungry).

    This is some really intriguing insight and sounds like an awesome time to meditate in peace and quiet.

    Great post Mark!

  36. I fall asleep early, around 9pm in preparation for my 4:45am wakeup call, but I always wake up somewhere in the middle of the night to pee (8+ glasses of water a day) and/or just wake up. I feel a panic to fall asleep again so I get as close to 8 hours of sleep as I possibly can. If it’s the weekend, I don’t feel as desperate, and can usually drift off into a nice second sleep.

  37. My babies slept with me and they nursed often throughout the night, I probably woke up 4-8 times a night, but because I never fully woke up, got up, or turned on the lights, I always felt very rested whenever we got up, I can see some truth to this post, and find it interesting. At ages 3 and 5, my kids still awaken at least once in the night.

    1. Me too. I think any mom knows that it’s not natural to sleep 8 hours straight as long as there are children in the house 😉

  38. as i got older, i started to notice the TCM principle bearing down on me – that is – to get to sleep before midnight (traditional chinese medicine advocates this as “proper” rhythm) and where i used to get by ok – sleeping soundly till 9 or 10 am after a 3 am writing working binge (or party) at 56 i can really see the benefits – a better mostly non-interrupted sleep though the night if i get my head down before 12–

    that said – my biggest current reason to wake up is the sometimes bad dreams of my 3 year old – last night was a 3 am wail: “OK MOMMY I’LL BRUSH ME TEETH PLEEEEEASE”

    poor little sausage – (we’re pretty strict with the theth thang…)

  39. You’re bang on when you say it’s all about perception … as soon as I even saw the title of your post I knew I had to read it, because there’s such a large part of me that feels I’m a failure for not sleeping the requisite 8 hours each night … sometimes it’s because I truly am staying up too late or pushing the morning alarm too far, but often (and even despite those things) I do feel great on less.

    Interestingly, as a former insomniac I never woke during the night but rather tossed and turned at the start of the night (often all night; usually until at least 3 or 4am) … but what I have noticed is that there have been the odd occasion when I wake during the night and then I get up and write and write and write – sometimes I might even think my best work!

    Perhaps if I started to view that sort of activity as normal or healthy it would actually ‘work’ for me … although I guess I should probably switch from writing on computer to journalling!

  40. When my children were infants I never minded the middle of the night(2:00 – 3:00am)feedings. I always felt pretty good during that time and looked forward to that feeding. It was the 11:00 PM feedings that were the worst. I guess now I know why…

  41. I remember a friend in high school telling us that she did this – she’d wake up at 2 or 3 in the morning and then do her homework before going back to bed. We all thought she was strange. 🙂

    I’ve always woken up in the middle of the night, sometimes for an hour or so and sometimes only briefly. Recently I’ve discovered that even on the nights when I thought I slept solidly, I didn’t: I’ll wake to find that my computer’s charger has been unplugged, wrapped neatly, and put away. When I then think about it, I’ll remember waking up and doing it.

    I definitely sleep better all-around, biphasic or monophasic, without the excess carbs and sugar.

  42. My perception has now changed on how I “should” be sleeping. Next time I wake in the middle of the night I will try to use that power hour instead of laying around thinking when I will get back to the zzz’s.

  43. I’m a teacher with a little boy at home, so I start my school work when he goes to bed. I’m often up very late, and average 4 hours of sleep a night. I find that getting more sleep than that actually makes me feel worse in the morning. Six hours of sleep just kills me. Recently, my son has been sick and I’ve woken between 1 and 3 AM to his coughing. I thought it strange that I felt refreshed and wide awake then, but struggled to get out of bed just a few hours later.

    Mark, for someone like me, would my first and second sleep be divided into just two hours, or have I “worked through” my first sleep by going to bed so late? What effect does REM sleep have on the biphasic sleep theory?

  44. I live with the spirit of a man who has learned to communicate with me using a certain type of nightlight, which he sets off by himself. It’s very pretty, actually. I have these lights all over my studio, and typically I fall asleep to them in my recliner.

    I usually wake at some point during the night, have a little “chat” with my ghost friend (who is always wide awake at night), maybe meditate a little, then go down the hall and get into bed with my boyfriend. The whole thing is very weird, but oddly soothing. I’m quite used to it by now.

    I sleep much better since I work at home now, and don’t have anywhere to go in the morning. So waking up at night is quite enjoyable. I love how quiet it is when everyone else is asleep.

  45. Maybe the nightly wake up is part of our cave man genetic heritage. We generally accept that we can’t handle a lot of carbs because our genes haven’t evolved enough. Don’t forget that we also were exposed to predators when we slept. Perhaps we evolved so that a 4 hour window of first sleep was optimal for our survival. Any sleep that we got after that was just gravy . . .

  46. i wake up every single night at between 2 and 3 normally, no exceptions. i pee, crawl back in bed, and usually fall back asleep within 20 minutes. this has been how i’ve lived my entire 40 years. to me, biphasic sleep is simply a pee break.

    1. Me too! My husband makes fun of my 80 year old bladder (while the rest of me is 24), but now I know he’s the weirdo for being dead to the world for 8 straight hours.

      We just got a puppy who recently started sleeping on our floor (b/c although waking up once may be normal, staying awake for 2 hours listening to barking multiple times a night is NOT). He sits in the bathroom while I do my thing, then I take him out to do his thing. It’s our bonding time:)

  47. Very interesting article, thanks Mark!

    What about polar nights and days? I’m curious to hear how my ancestors fit your darkness theory… I was born above the Arctic Circle and for a couple of months a year, we don’t get any darkness at all (and the opposite).

  48. Now i know why i ALWAYS wake up when camping, guess i shouldn’t feel so bad about having to get up and stoke the fire before dawn.

  49. What about afternoon sleep? I can sleep pretty solid (I think) 8 or 9 hours a night but I’m never really refreshed until I had a ~20 min afternoon nap. My sleepiness progressively worsens until 4 or 5 pm when I go, if I can afford, to sleep. This is ok, but a) I don’t understand why and b) it’s not always work/social friendly.

  50. This is fascinating stuff!

    Incidentally, in the transportation field we are well aware that “8 hours of sleep” is actually two 4 hour chunks. In fact, in the railroad industry, the employer is allowed to schedule you such that you get two 4-hour periods in a 24 hour period. We hold no illusions that this is optimal for alertness–it’s more of a bare minimum standard–but it’s based on scientific studies of sleep and alertness that showed that it is well into a 2-3 hour stretch that the body enters into the healing deep sleep phase. (4 hours uninterrupted lets you stay there for 1-2 hrs.) The sleeper then ‘surfaces’ at the end of the 4 hour period. So it is not surprising that someone who went to sleep early (naturally, because of darkness) might entirely wake up for a while on their own. Even people who do not consciously wake up surface to a very light sleep level when the deep sleep cycle completes.

    Just as a side note, I think the regulations for commercial drivers and RR workers still need some work. CDL drivers are given EXACTLY 8 hours off as legal minimum. Unless you report to your car and sleep in your clothing, you actually have to: commute, eat, put the kids/dog to bed (or whatever), fall asleep, wake up early, bathe, dress, commute. How many hours of sleep does that leave you?! But I have known a number of drivers who made it a habit to sleep 4 hours during long split shifts*, giving them plenty of active hours during their mandatory 8 hours off. 😀

    *A split shift is just what it sounds like–a number of hours on, a number of hours off, a number of hours on. Let’s say you are a 40-hour/wk (full time) employee. You might work 5:30am-9:30am and return to work 3pm-7pm, for a total of 8 hrs in a 13.5hr period. There are also part-time split shifts, with each piece being 2-3 hours each (typical for school bus drivers).

  51. Also–did anyone else read this and think of “The Night Before Christmas”? How about the witching hour?

  52. I think the answer is pretty obvious – do what’s right for you personally. If you feel good with 8 hours then do that. There’s no right answer for everybody.

  53. We have never enforced bedtimes or any rules around sleeping with regard to our children and, as a result, all three reflect this biphasic sleep pattern. Especially my youngest … he will fall asleep within a couple hours of sundown, no matter where or what he is in the middle of, and wakes up during the very early morning hours (2-3am) every night. He is never awake for long, but if he isn’t already in bed with me, he will find his way into my bed, if he is, he adjusts, wakes me up with a request to snuggle. And he is almost always first up in the morning, right with the sun. I am glad to know that I don’t need to stress about the 12 years of interrupted sleep I have experienced since having children … they are just keeping me primal! Amazing how primally tapped in our children can be when they don’t have standards of conventional wisdom forced on them.

  54. DH & I regularly have “slumber parties” where we wake up & cuddle & talk for an hour–usually around 3-4 am. We get really good sleep when this happens!

  55. Great post! Very thought provoking.

    I nurse my 14 month old who goes down at 8pm, wakes up a 12:30 and 4:30 to nurse like clockwork, then sleeps until 6:30-7. It works out great for both of us! It’s nice to have reassurance that this way of sleeping is normal to the human condition.

  56. This is definitely eye opening. I am one where I wake in the middle of the night, but am wide awake, but I cannot wakeup, for the life of me, in the morning.

  57. Huh, isn’t it interesting that having someone tell you it’s ok makes it ok! I used to think I was awake so I’d just get up and go off to the gym at 4:30AM

  58. For years and years I have awakened every night several times. When I had to be at work by 4 AM, I would stress out about it and be a clock watcher. Actually blamed my job’s hours about my sleep quality.

    15 years later, without that job, I found that over the years I awaken less times during the night and don’t panic about it and have learned to enjoy that time for day dreaming, thinking, planning. Direct correlation? I think so.

    In fact I have friends who take sleep meds and when they still can’t sleep “through” the night, I suggest they just accept it and go with the flow, so to speak. They can’t believe that I am so rested with my “interrupted” sleep pattern. May have to send this article to them.

    I also enjoyed the late night feedings of my three babies……so stress free, no demands and totally connecting with the wee one.

    I like to sleep outdoors during the summer on the patio overlooking my backyard and water feature (something I planned during my awake times.) I usually get up at least once and sometimes walk around my yard and in the morning, laying there, watching the sun come up and the birds and animals is so peaceful. Great start to my day!

    Thank you again, Mark, for confirming what my body already knew.

  59. I have been using a Fitbit to monitor my walking and it also monitors my sleeping too. I found I have A lot of active times in my sleep period. one of my kids who never seems to sleep like me has a similar pattern.
    Being out of work has let me sleep on my time more often, and I know I tend to fall asleep with darkness and wake with sunrise, even if the room is blacked out. But I also know I have waking periods where I have to do something or sometimes need food. I often avoid reading as I then dont stop until I finish book or have to do other things.
    My husband sleeps like the dead and two of my kids also tend sleep all night too, so some of us are probably pogrammed to sleep longer stretches some are not.
    I do have a preference for dark rooms for sleeping or moonlight/starlight options.
    I do like using the Fitbit to monitor my sleep habits so I can also see how drinking a couple glasses of wine, or certain medication is affecting my sleep activity besides just knowing about my waking periods etc. Also since I journal or note my waking moments can compare my notice of waking moments or dream recalls with the sleep activity. I apparently toss a lot in my sleep lol.

  60. Whenever I’m sleeping outside by a fire, I always wake up to feed the fire and I fall back asleep so easily. If you think about how our ancestors slept, it would be very rare to get 8 hours of sleep. The fear of predators probably kept some people awake, like the sound of a lion. But with a fire it really adds moral and elimenates most fear. And of course through-out the day we would take naps whenever we felt like it. It’s not like we had much else to do lol.

  61. Thank you so much for posting this! All my life I have suffered from waking up in the middle of the night. Thinking this is a huge problem, I would get upset and have trouble getting back to sleep. Now, I can just happily wake up and do something relaxing for an hour and go back to sleep. Mark you are so right, realizing this isn’t a problem actually has me looking forward to my free hour tonight!!

  62. Wow, thanks Mark. I needed this. For years I have not been able to sleep more than four hours without waking up and not being able to get back to sleep for 1-2+ hours. I would love to be able to get up during that time (not to have a cigar) but it would wake everyone else up. Instead I get stressed just lying there thinking “why can I not just sleep through the night like everyone else?”. I usually end up that stressed it can take 3 hours before I fall back to sleep and then I get up the next morning feeling very tired. I have been working on the theory that I suffer insomnia and that I need solid sleep. The fact that I have not been getting it has been increasing my stress levels. Unfortunately, my husband does not like to be woken up in the middle of the night, so I am on my own when I do, but I think I might just see what happens with a change in attitude. I will try something different tonight when I wake up, instead of stressing about not being asleep!

  63. This makes sense because the second sleep in the mourning feels so deep and primal. this will definitely change the way I sleep.

    New commercial funded by pfizer : Do you have trouble sleeping though the night ? thats fine there is nothing wrong with you. just kidding you need powerful chemicals.

  64. I for one know that I fall into the `stress out when I wake up in the middle of the night` category. Nice to hear a fresh perspective and re-examine my own thought patterns. Thanks Mark.

  65. Another option is shorter duration night time sleep, with one or more short-duration naps during the day. There is some interesting data out there.

    “Problem napping and disruptive behaviors were also associated with longer nighttime sleep, shorter nap durations, and later rise times”

  66. Mark (or anyone) –

    What are your thoughts on eating in the middle of the night, in between these 2 phases of sleep?

    I’ve self diagnosed myself with NES (Nocturnal eating syndrome), whereby I wake up in the middle of the night and “need” to eat. It’s bad enough where I plan, precook, and have meals ready for this (otherwise I’ll probably binge on something less-than-primal).

    Anyway, just wondering if eating in the middle of the night is considered…bad?


    1. Evan, I used to have night hunger all the time. Like seriously, ALL THE TIME. Since I stopped eating grains and upped my protein and veggie intake, I rarely have the issue anymore. I think it’s a blood sugar issue, and that I actually have the same symptoms – feeling hot and sweaty, shaking, and having racing thoughts – during the day when I have a blood sugar crash too, I just don’t notice it in the same way. How long have you been on the PB? I’d be interested to know if your NES goes away as you get your blood sugar stable.

      1. Maggie, Appreciate the reply! I’ve been on the PB for, I believe 14+ months now. Started off pretty strict VLC, then relaxed and added carbs here and there.

        Ummm, the NES thing is weird, sometimes it hits hard, sometimes I do get an 8 hour uninterrupted sleep. Started in college (would wake up sweating and needed to cooldown so I ate icecream or drank a cold liquid).

        Typically though, I’ll fall asleep then wake up 1-3 hours later then HAVE to eat. Uncontrollable urge. Been trying out all types of “tools” – IF, VLC, Leangains…

        Do you eat VLC now? I’m wondering if its because I eat semi large meals prior to bed…? (1st meal for me is usually ~ 6-8pm).

    2. I am contemplating eating something during the middle of the night as well. If I am going to be wide awake at 2am, I may as well enjoy myself. I do find that if I have something to eat it is easier to go back to sleep afterwards. For me it is not a matter of being very hungry, and I have been 100% primal for about 8 months now (so I don’t think it is a blood sugar issue). I think a primal snack should be okay. I would like to hear Mark’s view on primal snacks in the middle of the night though.

    3. Mark,

      have you tried having your dinner shortly before you go to bed? I feed my hunger at around 9-10 PM and if I have a few strips of bacon or something on top of my meal, I can easily IF until AM next day. Never really “had to” eat in the middle of the night though.

      1. Tomas – Actually yes…I typically IF from whenever I last eat at night (usually 3am or so) until 6-8pm the next day. No hunger pains at all, no crashes, no mental fog, perfectly fine. Work out fasted, performance seems good day in and day out.

  67. Maybe it’s not one or the other? Sometimes I can do just fine on 5 or 6 hours of sleep, but lately I have found that I feel most rested, most tolerant (I work with pre-schoolers, hello!) and most happy when I get 9 hours of sleep a night. However, I can’t do it every night. I’m starting to follow my rhythm more closely, and one thing above all else has helped me do that: turning off the technology. Seriously. I have realized that watching TV at night makes me completely unaware of my body’s signals. I can watch it till midnight and not feel tired, whereas when the TV’s off I notice that my body naturally starts to feel tired around 9-10pm. Interesting, right?

  68. I think this is a very appropriate post. I was a sleepwalker as a kid, and I still talk (work) in my sleep if I am super stressed out. I will awaken tired and groggy if I have been “working” in my sleep. Otherwise, I sleep like a rock, and have always.
    Nowadays, I will frequently enjoy a glass or two of wine before bed, and this seems to surpress the “night talking”
    On the rare occasions that I wake during the night, due to hubby’s snoring, or a child in need of comforting,(slept with my nursing babies, so precious!)I don’t feel any worse off in the morning!
    My Mom is well into “the change” right now, and is plagued by insomnia..although she was always up in the middle of the night, perhaps I should forward this post to her!

  69. I have always wondered why ship’s watches were set in 4 hour increments traditionally. Sailing is steeped in tradition from the days of tall ships, and this sheds some light on it. Sleep blocks of 4 hours would follow a natural circadian rhythm considering there is nothing but starlight, moonlight, and a smoking lamp out at sea.

    I personally have some serious issues to work through with my sleep, but this is some great info to take in! Thank you Mark.

    1. “I have always wondered why ship’s watches were set in 4 hour increments traditionally”.

      They weren’t, usually. There were three four hour watches and two six hour ones each day (and night). The longer night watch allowed sailors enough sleep to avoid sleep debt building up, and the longer day one allowed them personal time for things over and above necessities like getting a meal, washing, maintaining their own kit, etc.

      Also, as there were five watches in all, and that is a prime number, any breakdown of the crew into fewer sets was coprime to that and they would all cycle through every watch and get the watches they needed – which might not happen with six four hour watches. If a ship only had enough able bodied sailors to do watch on/watch off, everybody cycled through every watch every two days – a sustainable pace with that pattern.

      1. Looking over that, I see that it might be misleading as I wasn’t specific enough. Formally, under the system that got standardised, the longer watches were actually two watches – an ordinary one run into a shorter, two hour “dog watch”, with the two dog watches back to back. The crew would only sometimes run the five watch pattern in practice by running an ordinary watch and a dog watch together, when they were so short handed that they had to do watch and watch – two sets of sailors, alternating – but not overworked by a six hour watch. When there were more sailors, or a different and heavier workload so that six hours without a break was too much (like “rounding the Horn”!), it was more practical to work the dog watches separately (making seven distinct watches, so the prime number thing still applied). But the five watch system matches sleep needs better if you can’t get a dog watch off next to another one, and was probably the first pattern historically.

        By the way, originally “watch” meant “stay awake”.

        1. Wow! That’s super cool info… thanks so much for posting this, P.M.

  70. I spent two years trying to fight insomnia. We have two toddlers who enjoyed middle of the night talking, playing, crying, etc. It was ugly. Friends asked often if I were ok because my eyes were red? My wife (who works from home) never truly appreciated it until things got better (we got a king-sized bed and the kids’ sleep stablized).

    During that time, I started researching biphasal sleep. Taking an afterwork nap (I’m a school teacher) and embracing the the 90-minute blocks of deep sleep helped. I know now that 4.5 or six hours of nighttime sleep will be good. Now, if I can just get up when I wake at 4a.m. and do some writing or go for a swim instead of laying there thinking after I pee, I can get two more hours….

    1. Maybe I’m missing something but, if you are on watch for four hours you must stay awake, correct? Thus leaving you the other 20 hours of the day for other duties and sleeping. So isn’t this point irrelevant?

      1. You are missing something. Ship’s watches didn’t mean that each crew member just got one watch on duty out of the whole day, unless it was the very unusual situation of a vastly over-manned ship (in which case, it was very important to find work for them to avoid problems from idle hands breeding discontent). Rather, the crew was divided into watches to ensure full coverage with sustainable patterns of breaks, which meant each sailor was on duty for several watches during each day. If the ship was short-handed (from illness and casualties, say), that might even mean “watch and watch”, i.e. each sailor was on duty every other watch and only got short breaks.

  71. I used to sleep like a baby and never wake up. I felt fantastic when I awoke in the morning to begin my day.

    Recently I have been waking up in the middle of the night. I am not sure why but instead of becoming frustrated over this fact I am now going to welcome it. I feel awake when I do get up before I officially get up so maybe I should get up and do something for a short period of time.

    Thanks for this post Mark!

  72. I have a two year old, so I haven’t had an uninterrupted night of sleep in about three years. What I wouldn’t give for a full eight hours!

    Seriously, though, during the last several months I have been waking at two a.m. Wide awake and alert. While this frustrates me to no end (read: huff and puff and pull the covers over my head while trying desperately to regain some shuteye), this post gave me pause. Indeed, perhaps my much-needed quiet hour of “me” time is coming in the middle of the night? This will really be good food for thought. Probably at two a.m. tonight. =)

  73. My “normal” sleep pattern without fail involves peeing at least once/night, usually after a period of approx 1-2 REM cycles. Sometimes this pattern repeats. It’s rare for me to NOT do this, and I’m usually well-rested in the AM barring some other strange situation.

  74. Our kids are 8, 5, & 2. No way in hell I’m getting 8 hours a night. More like 6 that is broken up. Good times. Can’t wait for them to grow up so I can sleep outside by the fire. 😀

    1. 😀 Those were the days. I used to curl up on a large sheepskin rug in front of the fire for afternoon naps.

  75. This could explain why my oldest son (8) gets up in the middle of the night, eats, watches alittle tv (sometimes skips this step) and then falls asleep on the couch. He’s always well rested and ready to go at 5 or 6 am.

  76. This winter I’ve been stuck working overnight security, midnight to 8am, and at the beginning it was absolute murder. I’d sleep from 9 to 4 and never get to see sunlight. I was depressed, had no energy, no appetite, it was awful. Now I sleep from 9am-12pm and go back to bed in the early evening when the sun sets (around 4 or 5). I only get 6-7 hours of sleep each day, but I have more energy than I’ve ever had in my life. It was amazing to find how natural two periods of sleep each day feels.

  77. You may have mentioned this previously, but I’ve been using F.lux ( for a few months, and I *do* now find I slip more easily into sleep after shutting down my HAL-9000.

    On the subject of late night light pollution, is it just my crotchety imagination as a child of the ’70s, or are supermarkets and drugstores now *much* brighter than they were 15-20 years ago? I practically feel I’m having an “I’m coming home, Uncle Eddie!” NDE every time I shop for food at 12AM…

  78. 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.

    1. 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!

      1. @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.

        1. I took something called AdreCor which has C and B vitamins and a few amino acids plus rhodiola rosea extract.

      2. 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.

  79. 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…

  80. 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.

  81. 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.

  82. 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.

  83. 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.

    1. 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.

  84. 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.

    1. 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.

  85. 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.

  86. 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.

  87. 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.

  88. 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…

  89. 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.

  90. 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!”

  91. 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.

  92. 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.

  93. 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.

  94. 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).

  95. 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).

  96. 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 🙂

  97. 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!

  98. 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!

    1. 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!

  99. 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.

  100. 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!!!!

  101. 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.

  102. 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.

  103. 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…

    1. 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.

      1. 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.

        1. 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 🙂

  104. The period between the two sleep phases presumably was (and still could be) a good time for procreation.

    1. 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…

  105. I can’t remember the last time i woke up during the night, however, i do find the idea of regulating sleep patterns absolutely nauseating. I don’t want to go to bed at 9 every night. Sometimes it’s later, sometimes not at all, sometimes i sleep in till ten, sometimes 6am. Unless i eat crap, then i’m never tired from this. I think it’s great to do an all nighter from time to time, sit up listening to music or reading/writing/d1ancing(i love dancing through the night)(no computers though)). When i’m at my folks farm sleep is the best. Window wide open, sleeping naked, fresh air breezing through, the sound of the stream trickling away, the odd baa of a sheep, moonlight shards illuminating the bedroom walls and so on. I miss that terribly in the city, although i sleep just as well, but perhaps a bit less naturally if that makes sense. Yeehah!

  106. As a long time rescue swimmer I know the value of quality sleep, and I can personally attest that the perfect 8-hour night is not a necessity. The key to productive sleep is reaching that deep REM level of sleep which may be different for each person. I have survived many difficult times out to sea with 3 hr. sleep cycles and with entirely underestimated power nap (10-30 min). Your health and nutrition play a large roll in quality sleep as well. Supplimenting your normal diet with B-vitamins and other ingredients that provide your body healthy energy (try will help you stay active throughout the day and your body will naturally seek that deep sleep when the time is appropriate. Has anybody tried logging their hours of sleep to find their ideal range?

  107. Among people who live outdoors (travelling Rennies and homeless people living in tents spring to mind, seeing as how much of my early twenties was spent falling into one of those two categories) encounter this a lot. You go to bed a bit after sunset, sleep for awhile, wake up, go to to the bathroom (a hike of between 500 yards and a mile depending on the campsite) and then hang out at the fire, with people who were still up, smoke a cigarette, and then wander back to bed for the rest of the night.

    It’s a nice cycle.

  108. In classical Luganda (the widest language of Uganda, which first encountered European influence in the late 1800s), the times of the day are named in a more qualitative manner (“the time when the fireplace goes cold”), as opposed to the modern qualitative way (“10 PM”).
    Interestingly, and in accord with this that you write above, their 11 PM was called “Ekisisimuka ekisooka”; literally: “the first stirring to wakefulness”. And midnight was called “Ekisisimuka ekisooka”; literally: “the second stirring to wakefulness”. The ancient names for the times of the day (and night; to them the day was when the light was on, and it did not cover all twenty-four hours) are very instructive into that kind of time.

  109. It’s rare when I have a completely uninterrupted night of sleep. When I do, they’re quite awesome. The kind of sleep that feels like you just had an hour or so of sleep, but actually had a full 8 hours of it. Those days are great, but I usually wake up at least once during the night. It’s usually around the same time(s) too. I notice if I keep the same sleep patterns all the time I actually wake up peacefully usually 5-10 minutes prior to my alarm going off. I opted for a natural alarm clock (by Philipps)which gradually lights the room up with a “natural soft light”. I have it set to birds chirping to wake me up, but it’s a lot better than the usual beeping. I also makes sure to have my windows cracked in my room to allow air to circulate. I also make sure no electronics are in my bedroom. No TV, or anything that can disrupt my sleep. It’s pitch black when I turn everything off, other than the very dim light coming from my alarm clock. These little things alone make a huge difference.

  110. Hey guys,

    I found this article very interesting in that it provides good insight into why the modern-day lifestyle may not be compatible with our internal clock.

    If anyone is interested, here are two articles about polyphasic sleep:

    It’s already been pointed out that different non-developed cultures have totally different sleep preferences than us.

    The basic idea is that by sleeping in several blocks (instead of one 8 hour block) gives you more REM sleep and yet you spend less time “sleeping”.
    And, by doing this, we can achieve those so-called “sentinel” periods more often, and as such be more alert and more productive.
    Steve Pavlina from the second link explains what this meant for him.

    Point is, monophasic sleep seems to be the result of our modern lifestyle, not of our evolutionary preferences. People are able to adapt to different sleep cycles.

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  112. welll I know that at the moment i’m only getting about 3-4 hours sleep a night and it’s killing me….considering that once it’s daylight I can’t get to sleep at all…and it doesn’t matter how early I go to bed at night, I don’t get any extra sleep

  113. My vigorous and enthusiastic discussions with my husband are the only reason I really enjoy being up in the middle of the night.

  114. PBS aired a “Make Me”documentary a few days ago called “Make Me Cure Sleep”. It showed a man who claims he has only slept 2-3 hours a day all his life, and another man who gets by on 20 minute naps and regularly puts in an additional eight hours of work each night when everyone else is asleep. He was taking a drug that the documentary film maker also tried for a night, with interesting results.

  115. I really, really like my Mindfold sleepmask. I live in a bright city and I don’t have blackout blinds, so I wear one of these to sleep every night. I layer a cotton bandana under the sleepmask for comfort and cleanliness. It can also be used for relaxation and meditation. Highly recommended; darkness is so important for good sleep hygiene! Check it out:

  116. Thank you so much for this article! Once before I had run across another article about the historical “second sleep” and it makes so much sense …. as you pointed out the long hours of darkness that folks dealt with before artificial lighting came along. I’m particularly enthusiastic about your observation because I have discovered that my body naturally wants to do the bi-phasic sleep-thing. When I let my body tell me what to do, I will naturally get sleepy 1-2 hrs after sunset and go to bed somewhere between 7 – 8:30 pm. Then I will wake up anywhere between 10 – 11pm. I get up and write letters, watch a good movie, surf the web, or contemplate the meaning of life. Then I’ll get sleepy again between midnight and 1am and go back to sleep to wake up between 6 – 7am. When I do this, I feel good and fully awake. If I try to force myself to get 7-8 solid hours of sleep, I don’t sleep as deeply and I wake up groggy. So I’m all for getting back to natural sleep! Thank you again!