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. 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.

    Bobby wrote on February 23rd, 2011
    • 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.

      Richard wrote on February 24th, 2011
  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!

    Linda Grant wrote on February 23rd, 2011
  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.

    Kevin wrote on February 23rd, 2011
  4. I think cigar smoking might be almost primal…

    Vidad wrote on February 23rd, 2011
    • 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.

      Cordian wrote on February 23rd, 2011
      • 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.

        Vidad wrote on February 23rd, 2011
        • 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. 😉

          Grant wrote on May 24th, 2012
      • 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.

        Rocco wrote on February 27th, 2011
  5. 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!

    Johnny G wrote on February 23rd, 2011
    • 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.

      Vidad wrote on February 23rd, 2011
      • 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.

        Bobby wrote on February 23rd, 2011
    • 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!

      Julia wrote on February 24th, 2011
    • i am waking up exactly at 3:30 as well :)

      subashika wrote on March 15th, 2016
  6. 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.

    Joanne wrote on February 23rd, 2011
  7. 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.

    Purple Reign wrote on February 23rd, 2011
    • 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…

      jedimarkus wrote on February 23rd, 2011
  8. 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.

    Kelly wrote on February 23rd, 2011
  9. 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!

    Nannsi wrote on February 23rd, 2011
    • 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.

      Art De Vany wrote on February 26th, 2011
    • 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.

      Sandra Dodd wrote on February 28th, 2011
    • 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.

      Grant wrote on January 12th, 2012
  10. 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.

    Danielle wrote on February 23rd, 2011
  11. 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.

    Amy wrote on February 23rd, 2011
  12. 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.

    erik wrote on February 23rd, 2011
  13. 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.

    Ailu wrote on February 23rd, 2011
    • Ailu moving to the mountains and having better sleep is also attributed to being grounded. So kudos to you!

      Betty wrote on July 30th, 2015
  14. There is a great TED Talk video by sleep researcher Jessica Gamble about natural biphasic sleep patterns.

    Reid wrote on February 23rd, 2011
    • I mean Jessa Gamble.

      Reid wrote on February 23rd, 2011
      • … and she’s a science writer, not a sleep researcher. :)

        Reid wrote on February 23rd, 2011
    • Thanks for sharing Reid–great talk.

      WildShan wrote on February 24th, 2011
  15. 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.

    San wrote on February 23rd, 2011
  16. 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.

    wilberfan wrote on February 23rd, 2011
  17. 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!

    kateD wrote on February 23rd, 2011
  18. 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.

    Brian wrote on February 23rd, 2011
  19. 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.

    Gary Deagle wrote on February 23rd, 2011
  20. 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.


    Gordo wrote on February 23rd, 2011
    • 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.)

      Hedonist wrote on February 23rd, 2011
    • Maybe they were using the full moon for hunting… or fishing. Tides with full moon always bring in more crabs, etc.

      Mel wrote on February 24th, 2011
  21. 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.

    Jessica Tarbell wrote on February 23rd, 2011
    • Perhaps you should keep a notebook by your bed and write down your thoughts.

      Lynn wrote on February 23rd, 2011
  22. 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.

    Willow wrote on February 23rd, 2011
  23. 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 Iʻm not weird after all.

    Bull wrote on February 23rd, 2011
    • Sounds like my routine.

      Sara wrote on February 24th, 2011
  24. 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.

    Hedonist wrote on February 23rd, 2011
    • 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?

      ASmitty wrote on February 23rd, 2011
      • 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.

        Misabi wrote on February 23rd, 2011
  25. 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.

    Anika wrote on February 23rd, 2011
  26. 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.

    Jessi wrote on February 23rd, 2011
  27. 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.

    NWsenior wrote on February 23rd, 2011
  28. 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.”

    plutosdad wrote on February 23rd, 2011
    • 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.

      plutosdad wrote on February 23rd, 2011
  29. 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. :)

    DeeDee wrote on February 23rd, 2011
    • 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.

      Richard wrote on March 2nd, 2013
  30. 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.)

    Stephanie wrote on February 23rd, 2011
    • 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.

      Gazelle wrote on February 23rd, 2011
    • 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.

      Robert wrote on February 23rd, 2011
      • So it sounds like it’s an adjustment that takes some time. But there’s hope?

        Stephanie wrote on February 23rd, 2011
    • 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.)

      Rachael wrote on February 23rd, 2011
    • Try eating a bowl of cottage cheese before bed. It helps with hypoglycemia for some. It helps me when I need it.

      Sara wrote on February 24th, 2011
  31. 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.

    Kerry wrote on February 23rd, 2011
  32. 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.

    Judd wrote on February 23rd, 2011
    • 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.

      Blakery wrote on February 24th, 2011
  33. 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! 😛

    Heatherly wrote on February 23rd, 2011
  34. 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!).


    Ryan Denner wrote on February 23rd, 2011
    • 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. :)

      Betty wrote on February 23rd, 2011
  35. 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!

    Mary wrote on February 23rd, 2011
    • 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.

      Joanne wrote on February 23rd, 2011
    • 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!

      Kris wrote on February 23rd, 2011
      • creepy… but my doxies do too. they are part cat.

        Karyn (Calvin's wife) wrote on February 23rd, 2011
      • 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?

        Primalista wrote on February 24th, 2011
  36. 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.

    Samantha Moore wrote on February 23rd, 2011
  37. 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!

    Eric wrote on February 23rd, 2011
  38. 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.

    Karyn (Calvin's wife) wrote on February 23rd, 2011
  39. 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.

    Nicole wrote on February 23rd, 2011
    • 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 😉

      Cara wrote on February 23rd, 2011

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