Dear Mark: Sleep and Oxidative Stress

Dear Mark,

The time change pretty hit me hard this year. I’ve noticed that as I age I value my sleep more and more. When I was in my 20s and 30s I use to be able to get by on about 6 hours of sleep each night. Now if I don’t get at least 8 hours I pay for it. What’s the deal? Is this just part of getting older?


What’s one lost hour of sleep when getting over the hump of daylight savings time? It might not seem like much, but as I’ve noted before, time changes wreak a special havoc over everything from traffic accidents to workman’s comp filings. (Add the stock market and heart attack rates to this inspiring picture.) Truth be told, however, many of us were delinquent long before the recent changeover. Maybe the switch was simply the last straw in a long term bout of sleep deprivation. Anyone? (You know who you are.) We know we feel like hell warmed over when we make a habit of skipping out on zzzzs. We justify it, minimize it, though, by telling ourselves that it can’t be so bad if caffeine and a shower can cure us before we walk out the door in the morning. Some latest research says different. When we do without solid sleep, we decrease our ability to process even moderate levels of oxidative stress – the arch enemy of the Primal Blueprint of course. The impact, as observed by Oregon State University researchers, leads to faster aging and measurable neurological decline.

The key here is a so-called “period” gene, one of four genes primarily responsible for the body’s circadian rhythm, the internal clock related to day and night cycles and the essential biochemical pattern that helps govern major physiological processes. Studies have long shown that messing with the body’s biological clock can impair cognitive function in the short term and over the long term impacts cardiovascular and kidney function, since sleep aids the body in organ renewal. Now there’s more systemic-focused evidence for sleep deprivation/disruption’s ominous reach.

The Oregon State researchers compared fruit flies of different ages whose period gene was either intact or not. “Middle age” and older flies without the intact gene fared progressively worse and showed significant damage when subjected to moderate levels of induced stress. Flies without the period gene “lost some of their motor ability to climb” and sustained “neuronal degeneration” reflective of neurological damage seen in Alzheimer’s disease. In fact, a singular application of moderate stress was enough to cut a middle aged fruit fly’s lifespan by 12% and an older fly’s by 20%, when compared to both normal (gene-intact) flies and younger mutant flies, which didn’t show significant damage from the induced stress. Based on their results, the researchers suggest that the period gene plays a significant role in regulating the cleanup of oxidative damage in the body and is subject to gradual decline as we age. The older we are, the more we physically benefit from following our body’s natural circadian rhythm – and the more we put ourselves at risk when we ignore it.

As much as we’d like to chalk up this study to the particulars of the insect world, researchers believe that these genes work much the same in humans and in fact operate in nearly every cell of the human body. Despite all the years and achievements of civilization, we humans are still subject to the basic natural rhythms of the wild. When we live in denial of this correlation, it inevitably comes back to bite us in the backside.

Eating and exercising Primally both diminishes our overall oxidative stress levels and bolsters our body’s ability to eradicate the oxidative damage that is an unavoidable part of living. This study underscores how we can either support or undermine our Primal efforts by cheating our bodies out of sleep. If we’re religious about working in our meat/veggies or our supplements throughout the day, why undo the good once the sun goes down? If we wouldn’t dream of skipping a workout, why give up the crucial biological defense of a decent night’s sleep?

We mostly have good intentions when we shortchange ourselves on sleep. Maybe we’re up paying bills, reading a great novel, spending quality time with the spouse, putting the finishing touches on tomorrow’s presentation – or little Suzy’s costume for the class play. When we look at the results from the lens of continual damage and Primal backsliding, however, we might see sleep in a new light – and be more likely to declare “lights out” when our primal rhythms rather than modern life dictate.

Your comments and feedback on the study? Let me know your thoughts. And come back tomorrow when I’ll be publishing a brand new Definitive Guide.

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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62 thoughts on “Dear Mark: Sleep and Oxidative Stress”

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  1. Great post, Mark. I always emphasize the importance of getting enough sleep to my personal training clients. Diet and exercise are only two thirds of the equation!

  2. Excellent post. One of my “Primal Goals” is to get more sleep. It helps me break through my plateau.

  3. Mark, do you recommend using melatonin cream to enhance deep sleep? Also, is it better to work out during the day rather than late afternoon to ensure that cortisol or a ramped up nervous system is not keeping you up at night? Thanks!

  4. Mark I have a question, I seem to need very little sleep always have, My father and 1 brother are the same, and my 3 and a half year old seems seem to be developing along the same lines. I am now 40 and seem to do fine with 5 hours sleep during the week and 6 to 7 hours in bed but not always sleep on the weekends. Does the advice still hold I find if I get 8 hours sleep I am tired and more grumpy the next day.

    Just curious.


    1. Some people are naturally short sleepers.

      There’s a useful linke here:

      Margaret Thatcher (the Britain’s first – and so far only – female prime minister) was famously a short sleeper and could get by on 4 hours a night.

      If you feel good on five hours, then there’s no need to change.

      1. She was indeed, although you might wonder if some of her decisions were affected by lack of sleep! She also drank a fair amount of whiskey too and most interestingly she followed a very Primal diet in the lead up to an election in order to drop weight and have high levels of energy, it included fair amounts of steak, lots of eggs and green vegetables!

    2. Steven, my sleep pattern mirrors yours. Seven hours is perfect, but six, which is mostly what I get, seems to work well. In my fifty-five years, I doubt if I have had more than ten nights of sleeping more than seven hours. And when they occurred, they were memorable, as I felt as though only two or three hours lapsed between falling asleep and waking up, thus the miserable feeling throughout the day. I just sum this up to the idea that there is no such animal as a “one size fits all,” as preached by “experts.” After all, the “experts” were dead wrong about eating carbs instead of meat, for example.

  5. I find too little sleep is better then too much sleep for me. If I don’t set my alarm I sometimes end up going 10 hours before I wake up -_-

    I have to work on my sleep habits though. I’ve been going to sleep at 2 AM on most days, and too much sleep leads me to feeling tired throughout the day.

  6. Man i feel like your posts are following my life, ever since about two weeks ago ive been like an old man, im 20 right now, going to sleep around 11 daily and waking up around 7. Without a doubt i have felt way better and my days just run so much more smoothly. Oddly when i sleep later now i am more tired by the end of the day… we defininely have some rhythm are body is following just like in another post of yours, all our circadian rhythm wants to do is follow the sun

    1. yeah, this too has been happening to me, going to sleep around 11, waking up around 7, though sometimes like today i will sleep till 9 if i am really tired… but i struggle with staying up late these days, because my body gets set on schedules really easy and it takes me weeks to adjust my sleeping schedules
      and i’m 22

      but it feels good, the only problem is if i want to go to a concert or something on the weekends then i get ridiculously tired and have trouble staying up to enjoy them at night

      any ideas?

      i guess coffee…

  7. Cool study. There is a bit of a leap going on here from “flies with bad circadian genes” to “humans not getting enough sleep” beyond just the species. This is a link in the puzzle, but lets overstate things.

  8. All sounds like bad news for us shift workers! No matter how well I sleep during the day, it is not the same as night sleep.

  9. I haven’t finished reading the post yet, but need to comment on that first sentence.

    I didn’t lose an hour of sleep. I lost an hour of “awake”.

    Seems to me the choice really is yours…

    As for me, I started defending my sleep years ago!

  10. This is slightly off topic, but does anyone know of any sleep studies that account for the time of year that subjects are studied? I’d be interested to see the results of studies done during the subject’s winter season, vs studies done during the summer.

  11. Specially appropos since I’m running primarily off caffine today. ZZZzzzz….

  12. I quit using my alarm clock quite a while ago and love not hearing it ring! I either wake up naturally in time to work out in the AM or I don’t. If I don’t then I figure I needed the sleep and don’t stress over it. Absolutely insist on at least 8 hours/night!

  13. Very interesting.
    Quality sleep is great – when there is not much tossing and turning – it happens when I am tired… although not too tired, because then I tend to have a harder time falling asleep.

  14. aahhh nas soon as Monday rolls around to start a new work week i start looking forward to Saturday and Sunday sleeping in. i only get 7-8 during the week but i think i need at least 10 a night and on weekends usually sleep 12 hours!

  15. I have finally hit 8 hours of sleep the other day. I am one of the few crazys that looks forward to Mondays. I work in a stressful, high maintenance job that requires complete attention and focus so I live for that edge. I did fine without sleeping a full 8 hours but today I feel rejuvenated.

  16. I am lucky enough to have put sleep as a top priority for the past few years. 8 hours is perfect for me and I make sure I get that every night. Once or twice a month I may fail to sleep for 8 hours. Sleep effects your health in several ways.

  17. As the parent of a five-month-old, I crave a good night’s sleep like a glass of water in the middle of the Sahara. When I try to take a power nap, it’s like falling into a black hole. If any parents have discovered primal tips for getting sleep under these conditions, I’d love to hear them!

    1. My tip: get the baby to sleep through the night! Both my kids were sleeping 6+ hours at 2 months because we let them cry a little. They learn to self soothe that way. The older they get, the harder it gets.

      It’s a very personal decision, so I hope to not offend.

      1. Sorry, but that is NOT the Primal way. Having the baby sleep with you, so that Mama is close at hand and can feed on demand is the best way to get much needed sleep. Don’t let the “expert doctors” (we know what THAT means) tell you any different. Babies were not meant to be left alone to cry. Think of the danger in the wild to hear a crying baby! This will pass soon enough. This is a wonderful time for bonding.

    2. I hate to say it, but the thing that saved sleep for us at that stage was . . . letting the baby into the bed. It’s not for everyone, but it is primal! (Kicking her out again also saved sleep, but that was a year later).

      One other possibility might be to aim for what anthropologists call “biphasic sleep” — that is, crash early enough that when you get the main nighttime interruption you and your partner can wake up, be awake for an hour or so, and go back to sleep without suffering for it the next day. Apparently this is how people slept before the advent of gas lighting, and is still typical of hunter-gatherer societies. You’d be giving up your evenings (you’d probably have to go to bed around 8) but it might be worth it, if option A is no good.

      Either way, good luck. And take heart! At five months, you’re on the downhill slide. More sleep is coming! I promise!

      1. That should be “around eight)”. And naturallycheryl is right, crying it out does work too on most kids. Just depends on what you’re comfortable with.

    3. Our strategy (again, a very personal one) was co-sleeping. It made all the difference with both our girls. We didn’t have any problem adapting them to the crib either when the time came. Good luck to you – it’s such a difficult time but you will get to the other side!

    4. Cheryl, Patricia, Jennifer, thank you very much for the parental advice! We do sleep with the little guy in our bed, and occasionally it works great and he only gets up once in the night, but other nights he just won’t stop flailing around, possibly from gas that we can’t burp out of him.

      He likes to take a nap around 7, and that’s earlier than we normally go to sleep, but then he’s up until 10 or so which is definitely late for us.

      Patricia, I think you’re right that we just have to bite the bullet and get ready for bed after the sun goes down, when he gets ready for his initial nap. We may not be able to get 8 hours uninterrupted, but maybe we can get, say, three naps of three hours each, and that’s probably more primal anyway.

      Learning to go to sleep at night, rather than stay up entertaining each other under artificial light, has been one of the more challenging lifestyle shifts. The light is probably most disruptive to the baby. But we’ll figure it out somehow, even if we have to resort to candles after sundown.

      I’m looking forward to his teenage years when he refuses to get *out* of bed. If you’re a parent with that problem, count your blessings! 🙂

      1. Neither of my children shared my room or bed from day one, they had their own crips/cots in their own rooms, they had regular bedtimes between 6 and 7 each evening (with dark curtains when necessary) and I went in to feed them as they required through the night, after the initial few months when obviously they do need to ‘eat’ regularly they still kept waking, until I used the controlled crying technique.

        Let them cry for a few minutes only going in to quietly check they are ok and retreating, over several nights they stop ‘needing’ to call you unnecessarily and started to sleep 8-11 hours and have continued to be good sleepers now 18 and 21.

        It is very personal but I do think it set them up for good sleep habits. Of course during their teenage years it was hard to get them to sleep senisbly but they don’t have trouble if they manage to turn off all the digital media!

        Don’t wish the teenage years on yourself too soon … that’s a whole other ballgame LOL!

      2. That 7pm nap should actually be his bedtime believe it or not. If he wakes up after that, treat it as nighttime — feed/change/whatever he needs but in the dark w/ no talking, etc. My son is now 9 months and he typically woke 1-3x/night until he was 7 or 7.5 months. Now he sleeps 11-12 hours (!!!) and the only person I have to blame for not getting enough sleep is myself! Books I found useful were Healthy Sleep Habits, Happy Child (didn’t follow much of the advice but there is good research-based info in that book) and The 90-Minute Baby Sleep Program (I followed more of the advice in this one, it also has a good research base). Remember that babies aren’t typically neurologically mature enough to sleep through the night (I’m talking 12ish hours) until 6 months or later. They have certain survival drives (hunger, or if something restricts their breathing) that cause them to wake. Also, people talk a lot about training babies to sleep but they often don’t realize that it’s very easy to inadvertently train your baby to wake up, too! Put him to bed early and make nighttime boring and distinctly different from daytime. Good luck!

      3. A couple questions: is your wife working? If not, then why are you getting up also? If you both work, why are you not taking turns getting up with the baby? If your wife is nursing, then I’m not sure why you’d be getting up at all.
        There will be plenty of times (over the next 18 years) for “Dad” to be doing the hard things (maybe taking Jr. to 6am soccer or swim practice), but unless Baby is on a bottle and you are both working, this seems more like your wife’s sacrifice. Having been there five times, I know it’s no fun to be sleep deprived…by all means, she should try some of the methods suggested. (I chose co-sleeping) Good luck… and cherish these little kiddo days, the teen-age years really do come to fast.

  18. Two questions:
    1. Circadian rhythms – since humans are supposedly sensitive to daylight and exposure to it affects our hormones and the like, does that mean all humans should have the same (or at least very similar) circadian rhythms? ie. We all should desire sleep (if we aren’t being messed up by other factors) around the same hour at night, all should want to wake around the same hour in the morning?

    2. Do all people need the same amount of sleep? Can some (healthy) humans truly get by on 6-7 hours of quality sleep a night, while others (like myself) seem to need 10 hours to feel rested in the morning?

    As I mention, I seem to need a lot more sleep than anyone I know. I’m 27, but have always felt like I need a lot of sleep even as a teenager! I’ve never had that “I only need 5-6 hours!” experience EVER. Additionally, I tend to want to go to bed around 12-1 and get up around 10am. I can adjust back to 9-10 and get up 5-6, but I usually feel more tired doing that. What gives? I’d have thought I’d feel improvement with the earlier times. (Bear in mind I did the earlier times for months, not just a few days!)

  19. I know we’re not mice of course but i think you might find something very interesting on the Horizon programme about ageing (and oxidative stress)It was called something like How not to Grow Old
    I might have misunderstood what was being said vis anti-oxidants, oxidative stress and ageing but if i didn’t it suggested that the length of life, certainly not the quality of that life ofcourse,was in no ways linked to oxidative stress.
    The researchers describing their work said they were as suprised by their findings as everyone else BUT maybe i mis-understood…cos of oxidative stress !!

    1. This set me off on a little searching and indeed it seems the oxidative stress theory of aging may be a 50-year-old timber of conventional wisdom that’s about to fall.

      …Damn! just when you think you know something…

  20. Any advice on sleep?? I mean, i’ve read the blogs endlessly. I still know I don’t get enough sleep. There will be some nights where I’ll lay in bed for 4 hours just staring straight up. Or it seems like I wake up every hour on the hour when I do get to sleep.

    I’ve been eating Primal for a few months now and I follow a pretty regular 5-on-2-off workout schedule. Just can’t seem to get that sleep thing down.

    1. I just went through a period where I often had trouble getting to sleep. I have to say that I grudgingly tried the “no TV or computer after 7:00” thing, and I’ve been getting to sleep right away!

      1. I do the same thing if I want good quality sleep (no t.v. or computer). I also keep my bedroom for a sleeping room, nothing else….well one other thing.

  21. Man, this year (especially) the time change hit hard. Because I am becoming more aware of my body–I was going to sleep primarily between 9:30-10:30 each night. I was waking up between 6:00-7:00 each morning (unfortunately to an alarm, but I would usually wake up before it). The week before and the week after the change felt odd to me. It took me a full week to get to feeling normal and not moody/sleep-angered. What a crazy feeling it is to actually feel in-tune with your body so much that you realize something is off!

  22. My hubby and I have had trouble sleeping for a long time- he in particular has been in a state of semi-exhaustion for several years now. He has a CPAP for sleep apnea but it hasn’t really helped him sleep. We’ve also got a cosleeping baby that wakes and nurses through the night, which is precious but certainly doesn’t help. Recently though I read something on the forums here about Natural Calm and decided to try it. One week into using it and I can report we’re sleeping way better! It’s awesome stuff. It rid me of the restless leg syndrome I’ve had since pregnancy too. Apparently magnesium levels are very importantant, and mine were very low. Give it a try- I ordered it online but apparently the local vitamin store has it too.
    I don’t mean to sound like an ad but this stuff (like primal itself) is changing our lives for the better, and in short order!

  23. I love the sleep posts you have been doing Mark. With “Lights Out” first published in 2000 there have obviously been new findings since this great book first hit the bookstores. Some of these findings you have already mentioned here, including the importance of blue light in the evenings.

    Since sleep obviously plays a huge role in hormonal balance and therefore overall health, it deserves a front row seat here in the Primal community.


  24. Ahhh. I hate this topic. Reading about the importance of sleep always stresses me out because I’m an on call nurse so my sleep is constantly interrupted. I love my job and someone needs to do it, but I hate that it is detrimental to my health. However, since reading this site, I do try to take more naps in hopes that it buys me some benefit.

  25. It’s so easy to dip into sleep time when my schedule gets hectic and I feel there aren’t enough hours in the day. It helps me to set a time to go to sleep and stick to it no matter what.

  26. Just one of the many benefits from living primal for me was the improved sleep. I used to have inconsistent sleep patterns but now I go to bed at 11 and sleep until 6-7 and wake without the alarm clock. I still set the alarm but 90% of the time I wake before it goes off.

  27. Awesome Article Mark! Its amazing how the importance of sleep becomes greater the older we get. I used to look forward to staying up very late in my Youth. Now I look forward to getting to bed at a decent time! If we only knew then what we know now! Thanks for the great info!

  28. I cannot survive the day if I have less than 8 hours sleep. I have always been this way. Sleep had always been elusive to me until I started the Beachbody workout, ChaLEAN Extreme and started the Shakeology regiment. Since then, last May, I have had no issues with sleeping or falling asleep, unless I nap during the day. Funny that a daytime nap reaks havoc with my nighttime sleep…

  29. Why then do old people sleep less. My grandparents were in bed by 11-12 and up at 4-5? What gives?

    Shouldn’t they be sleeping 10 hours a day

  30. Since I started PB 1 week ago I have been waking up very early in the morning – maybe it’s my genes telling me to go hunting 😉 I hope it will change a little though since I need a little more sleep to get through the day.. On that note I feel I need less sleep the older I get..

    One thing that has dramatically changed my sleep quality is to get a woolen bed sheet. I used to wake up with back pains 3-4 times a week – but it is completely gone and I feel me sleep quality has been improved (way more than I ever expected)

    This is what I’m talking about:
    -sorry for my foreign web page – but just to give the idea – in pictures..
    I feel very warm sleeping in it – but never sweaty. I guess the increased heat without getting cold by sweat is one of the reasons it’s good for my back.. And pretty Primal too I would say? 🙂

  31. I just had to comment on all the people that are commenting on their babies sleeping. Ferberizing (letting the baby cry it out) is the new “conventional wisdom” on how to raise a child. I am astounded that the readers of this website are promoting it. Research has shown that babies crying it out undergo EXTREME stress, and when they finally give up (not self-soothe), they are learning that crying is not an effective way to communicate and that they are ultimately alone. My wife and I did try it, but we stopped the first time my child got so upset that he vomited on himself. If letting your baby cry it out has worked for you, wonderful. It does not work for everyone. There are many articles out there that talks about co-sleeping. It is, in fact, the primary (almost exclusive) method of taking care of a baby outside of the US. I can’t think of anything more instinctive than picking up a crying child or anything more Primal than a baby sharing the body warmth of his mother and father, and the intimacy and strength of the bond that develops. Do yourself a favor and look at all the options before using the cry-it-out thing. There are some safety guidelines that you should check out for co-sleeping safely that are important, but the idea that co-sleeping increases the risks of SIDS was debunked a while ago. Actually while basic safety guidelines are followed the chance of SIDS goes down dramatically with co-sleeping.

    The last time I put a link in a comment on this site, the comment was blocked which is why i have avoided citing my sources, but if you would like to email me, I’ll send you some really good articles. You can also google Dr. Sears and look up co-sleeping there.

    I definitely don’t want to appear critical of anyone for how they raised their child, and I’m sorry if I have come accross harshly. If crying it out works for you, by all means do it. For our family and millions of others it is not the best choice.

    1. I knew the controlled crying would prompt a response and I agree it doesn’t sound or feel very Primal. This was 20 years ago (my kids are 18 and 21 now), but it did work for my children, but it only took several nights, they never cried until vomiting, and in fact we never left them crying for long – more than a few minutes, what we did was go in and check they were ok, reassure them we were there but didn’t pick them up, just tucked them back in and retreated.

      Obviously I was lucky, but having to work regular hours in a modern life meant it did mean that at least one adult was getting a full night’s rest, which is very important too. Being crabby all day long with poor sleep doesn’t promote good parenting either and learning that you aren’t the centre of the world and that someone will come running as soon as you demand probably isn’t a bad thing either!

  32. I have always needed about nine to ten hours sleep at night and yet I don’t feel tired until well after midnight.

    All through school, and my varied farm employment I always feel sluggish if I get up before midnight, no matter what time I go to sleep. Similarly, going to bed early feels strange and I will often sleep for a few hours before waking up and not being able to sleep again with tossing and turning.

    After a month of having no classes, work etc I had developed a pattern of staying away for approximately 20 hours than sleeping 10 hours and I felt refreshed.

    Additionally, I can not sleep on a full moon.

  33. I, too, get stressed out reading stuff like this, though I know it’s true. I’m a lifelong insomniac and this is my biggest health problem. It seems when I can get all the planets aligned, exercise and eat at just the right times, with the right things, have a relaxing, but not too boring, night, etc., then maybe I can sleep. It’s a horrible problem. I have tried everything.

  34. * I meant to say: I always feel sluggish if getting up before 10 O’clockish, not midnight.

  35. Sleep unfortunately, I cannot control. I work as a firefighter/paramedic and am assigned to a busy rescue unit (24 hrs. on, 48 hrs. off) and we are generally woken up multiple times at night by loud alarms and flashing fluorescent lights. These calls 90% of the time, warrant a trip to the hospital (though, they don’t REALLY need to go and that’s another story all together), and calls usually last anywhere from 1-2 hours depending on the nature of the emergency and/or which hospital we transport to. Needless to say, I’m sure that with all of the primal eating and moving that I do, I’m sure my oxidative stress and cortisol levels are severely jacked. I try my hardest to make up for the lack of sleep on my off days but am also a full-time student so… Hopefully, the education will lead to a “day only” shift career and I can re-learn what good quality sleep is.

  36. I went through a period of about four months when I could only get 5-6 hours of sleep per night. (I had a pinched nerve.) What I got was not restful. My blood test results went south. LDL and triglycerides skyrocketed.

  37. Sleep is very important, and say just find a complete article on oxidative stress as well, many mendaptkan science .. hopefully useful. thank you for those of you who write this article. Good job

  38. the last decade or so have been horrendous on players and personnel, even Washington and Cleveland are making better decissions, this team has been destroyed so deeply