PolyPhasic Sleep- Part 1

This is a submission from my good friend Dr. Dan Pardi. I’ve received questions about polyphasic sleep for years. Well, here is a sleep experts  thoughts on the topic. Enjoy! Also Dan is a PhD candidate at Leiden University working with the departments of Neurology and Endocrinology. He lives and works in the bay area and conducts research through Stanford University under the guidance of two mentors in the department of Psychiatry and Behavior Sciences.

Polyphasic Sleep – Is it magic or puffery?


In Tim Ferris’ newish book, The 4-Hour Body – An uncommon guide to rapid fat-loss, incredible sex, and becoming superhuman, Tim offers a wide-variety of recommendations to improve one’s life and conquer various physical goals. Self-exploration to promote self-awareness, I believe, is a good idea and the goal of ‘hacking’ one’s lifestyle to optimize performance holds many temptations. The term “biohacking” essentially means finding efficiencies in a wide variety health habits and goals. Do you want to do more pull ups, jump higher, or live longer? Then how do you get maximal gain for minimal effort?

Our modern-day lifestyles ask a lot from us, and pressures from work, family, and a social life (if there is any time for one) incent us to find advantages and shortcuts where we can. How can I do something quicker, better, cheaper, and with less effort? How can I get more, and how can I get more for less?

From what I can tell, Tim’s process is to seek out experts and gurus in a particular field, become their student, and then undergo a period of self-experimentation where he implements their guidance. I think Tim has a cool life. It appears he can get access to just about anyone and he’s clearly a highly productive person who has created a nationally recognized brand name for himself. He is, if anything, a masterful marketer and therefore, businesses are crawling all over themselves to have him on board. If he endorses your product or idea, you’re going to have a huge increase in visibility.

I’m going to state my overarching issue with his specific approach upfront. While I believe his process is interesting and has potential to reveal valuable information, I also believe there are many limitations to the information one can derive from self-experimentation, and this becomes especially dangerous when your n=1 study becomes hard-and-true recommendations for everyone else, especially when this relates to health-related topics. It’s more innocuous to suggest that a technique helped to improve productivity, but I think it can be perilous in other arenas. Do I think it’s wrong of him to say “hey, I experimented with this and here’s what I learned?” No. However, I become uncomfortable when someone makes big claims from extreme protocols and then not-so-subtly implies that everyone will achieve similar results. In essence, his reported experience becomes a fact and a prescription. Now, let’s talk about how I think this approach fails for one very important topic: sleep.

In his chapter entitled, ‘How to fly like a bird with only one tablespoon of almond butter a week’ oh wait, wrong chapter, in his chapter entitled ‘Perfecting Sleep – Becoming Uberman – sleeping less with polyphasic sleep,’ Tim describes a method to modifying your sleep and wake schedule so that you actually ‘need’ less sleep. He writes, ”anyone can shave six hours off their normal sleep time. If you can manage to pick a (polyphasic sleep) method and stick with it for several months, you’ll find that you feel amazing and have a seemingly unlimited amount of time during the day to get things done.” Holy bovine bells, that sounds awesome! Tim goes on to state that for him “this is the ultimate brain hack.”

What is polyphasic sleep?

Polyphasic sleep is the intentional rescheduling of sleep across a 24 hour period so that you sleep in multiple, shorter bouts across the day and night instead of one consolidated sleep bout at night (i.e., monophasic sleep).  Polyphasic sleep mostly refers to sleeping more than twice (biphasic sleep) per 24 hour period and a variety of different protocols have been experimented with and described. Ferris did not invent polyphasic sleep, he has just popularized it with the success of his new book. The origination of this concept, according to this Wikipedia article, is owed to an early 20th-century psychologist named J.S. Szymanski. In other words, the concept isn’t new. The premise, stated by Ferris, is that polyphasic sleep can reduce sleep need because not all phases of sleep are necessary, and that the most beneficial phase of sleep is the REM phase: “…(during) normal sleep we experience REM for a mere 1-2 hours / night. To reap the benefits of polyphasic sleep, we’ll need to engineer things so that REM is a much higher percentage of total sleep.” He goes on to state “with monophasic sleep, you sleep for eight hours and you get about two hours of good REM sleep. This is the normal schedule most people use and it means about five hours of the night are lost to (as far as we know) unnecessary unconsciesness.” Huge red flag. Let’s say we don’t currently understand what is happening during these other stages – and, by the way, we do know about lots of important things that happen during those periods – then assuming the unknown is unnecessary is hubristic.

Not all polyphasic sleep adventurers ascribe to Ferris’ claims about reducing total sleep need. In fact, for many, experimentation with the concept is more about finding ways to gain additional sleep time and wake performance under extreme conditions. Robb recently introduced me to an ex-Navy Seal, Kirk Parsley, MD, who still works with Seals and their sleep schedules before, during, and after combat. Dr. Parsley informed me that a regular part of the Seal training is to deprive soldiers of sleep for a week in order to prepare these bad-asses for the possibility of extreme combat conditions where a full night sleep is temporarily not an option. The lesson for them is not that sleep isn’t important, but rather, this provides mental training to perform optimally under life and death situations. I believe the application of a polyphasic sleep schedule, under such situations is better than the alternative, which is less or no sleep at all. It’s been documented that naps improve performance under continuous work conditions, and in this scenarios, napping when the opportunity presents itself could lead to the relative preservation of cognitive and physical functions leading to survival. Napping during times when you cannot achieve a full amount of rest can be beneficial and should be considered.

In the heretofore mentioned Wikipedia article, several other evaluations of polyphasic sleep are described in various military contexts:

–        The U.S. military has studied fatigue countermeasures. An Air Force report states: Each individual nap should be long enough to provide at least 45 continuous minutes of sleep, although longer naps (2 hours) are better. In general, the shorter each individual nap is, the more frequent the naps should be (the objective remains to acquire a daily total of 8 hours of sleep).


–        The Canadian Marine Pilots in their trainer’s handbook report that: Under extreme circumstances where sleep cannot be achieved continuously, research on napping shows that 10- to 20-minute naps at regular intervals during the day can help relieve some of the sleep deprivation and thus maintain … performance for several days. However, researchers caution that levels of performance achieved using ultrashort sleep (short naps) to temporarily replace normal sleep are always well below that achieved when fully rested.

In support of Ferris’ contention that polyphasic sleep can reduce total sleep need, the Italian Air Force conducted experiments for their pilots and found some interesting results, which were then published in the International Journal of Neuroscience under the title Sleep and alertness during alternating monophasic and polyphasic rest-activity cycles. I wasn’t able to get access to this full article but the abstract is available here. This study evaluated 9 pilots under a polyphasic sleep schedule where 2 hours of activity were followed by 4 hours of rest. This pattern was repeated 4 times in a 24 hr day and was alternated with 24 hours off duty.  During these 4 hour rest periods sleep was allowed. The study found that during the polyphasic sleep days, total sleep time was substantially reduced as compared to the usual 7-8 hour monophasic, nocturnal sleep. This conclusion was derived based on the observation that these pilots were not experiencing a significant degree of sudden sleep onset episodes as anticipated (contrary to expectations). However, there are signs that these pilots were getting sleepier the longer they maintained this polyphasic sleep schedule. The polyphasic sleep schedule temporarily mitigated some negative effects of sleep loss, however, it would be incorrect to conclude that polyphasic sleep obviated total sleep need. I interpret these findings to suggest that within one 24 hour period, a polyphasic sleep schedule improved alertness on a temporary basis, and likely delayed sleep need.

It is a matter of current investigation to evaluate hysteresis within our sleep wake system. Hysteresis describes the dependence of a system on both current and historical conditions. Regarding sleep, the question of high interest – given modern day, endemic sleep deficiencies – is whether we have the ability to fully recover after a period of deficient sleep. The most common scenario is less sleep during the work week and more sleep on the weekends to recover and “sleep off” the sleep debt accumulated over the week. Of great interest is to evaluate our ability to fully recover after sleep loss and to have a better understanding of how many cycles of deficiency followed by recovery can be repeated before a significant decline in cognitive and physical abilities manifest. In other words, over a weekend of recovery sleep, you may be able to recover 100% from a prior week of deficient sleep. However, if you were to immediately try to repeat this pattern, you may only be able to recover 90% of function after the next week of recovery sleep. Again, this is a matter of ongoing investigation.

In order to fully address the theory of polyphasic sleep, it’s useful to review the primary mechanisms that drive the two very different (and sometimes, not so different) states of consciousness, sleep and wake. Before I begin, I would like to state that I am a self-described skeptic. Note, skepticism is not synonymous with cynicism, which is the default rejection of new ideas (i.e., guilty until proven innocent). A skeptic is open to the possibility of anything being true, but proportions belief according to evidence. I am open to the possibility that one can limit total sleep time without acute or long-term negative consequence and I would be excited about solid evidence that supported such a finding.

Importantly, the absence of evidence is not evidence of absence, so just because a situation lacks investigational data does not make it untrue. However, one should use caution when proceeding in such a situation where the preponderance of supporting evidence is self-reports. There is an old saying by Frank Kotsonis, “the plural of anecdote is not data.” In other words, self-report has limitations and you can’t overcome those limitations by throwing volume at the problem (i.e., a boat load of case reports will not wash away these limitations). Case reports are hypothesis generating and a next step is to perform blinded investigation to add controls, limit biases, and hopefully evaluate if a significant effect likely exists. This is a long, tedious process but it is necessary.  When this method is not utilized, the perception of a “real effect” – when no actual effect exists – may persist and cause many people to change their behavior. Sometimes this will simply cost you time and money. Other times, more dangerous outcomes are possible.

Additionally, incentives must also be considered. Ferris’ incentives to discover and promulgate a secret formula to give you more hours of functional wakefulness per day without a postliminary downside would certainly be a powerful influence on his judgment. His credibility comes from revealing secret formulas. These incentives could easily produce biases to filter and select information most favorable to his claim. This doesn’t mean we should write off anyone with a bias or incentive, it’s just good to make a mental note of this when reviewing someone’s treatment of a subject. Let me state my own biases upfront: I believe that a full night’s rest is necessary for current and long term health and performance.

In short, I recommend we proceed with two thoughts in mind: 1) buyer beware and 2) let’s give this a fair shake. Now let’s discuss sleep so you can make a decision about what’s right for you.

Dan Pardi is the CEO of Dan’s Plan, a ‘Quantified-Paleo’ company whose mission is to help anyone pursue optimal health in our modern world. The specific approach taken to achieve this goal is as follows: 1) Define success to understand what direction we are aim for; 2) Build a roadmap to get from point A to point B (now that we know where we are headed, how to do get there?); and 3) We help people ‘walk their path’ – are you living the lifestyle today, to be healthy today tomorrow? We focus on food, movement and sleep as three fundamental pillars of health, performance, and longevity. Visit our site and sign up for a free My Plan page to start tracking your health behaviors today.

Categories: General, Healthcare, Paleo Diet Basics, Paleo/Low Carb, Sleep


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  1. says

    I’ve always been interested in polyphasic sleep, but I’ve never been willing to take the plunge. While I doubt I’d be able to pull it off with my current job, perhaps next August when my contract’s up and I have some downtime I’ll give it a try.

  2. says

    Thank you for tackling this topic and also to Robb for hosting the article.

    I look forward to seeing what you have to say in the second part of the article but I have a concern about the studies you cite.

    The case-studies and military guidelines you mention are instances of short term polyphasic sleep and some are practiced ‘free-form’ rather than structured.

    The caveat on polyphasic sleep as I understand it is much like the caveat on a low-carb diet: you will feel like crap for 2-4 weeks until you acclimate. Any study that only looks at polyphasic sleep for days or weeks is not really evaluating the protocol.

    Are there any studies you can share with us that evaluate the program over a longer period of time?

    • says

      Hi Erik,
      Yes, these studies definitely have limitations as to what one can glean from them (like all studies, really). There simply aren’t many studies that have directly studied this and I’m not aware of any that are long term. In the next section, I talk about how the brain controls sleep and draw some connections between sleep and health. The second portion of this article should answer more of your questions. Let me know if you have more questions then.

    • says


      Its not so much needing to cut out sleep, but rather wanting to cut out the sleep.
      I am currently down to 4.5 hours total sleep per day and working 14-17 hours between 2 companies in 2 different markets.
      Working four hours a week can work very well to support yourself, but when you find that you can replicate the same process multi times through different products or industries, its nearly impossible to not want to start up more and more businesses.


  3. Sam says

    I practice polyphasic sleep cycles in extreme conditions…when I drink too much alcohol! I wake up after sleeping for only 2-3 hours and then am up for 3-4 hours before sleeping again for 1-2 hours. This usually happens until normal “bedtime” the next evening. From my personal experience…I like normal 8-9 straight every night.

  4. Ray says

    I absolutely love “The 4 hour body” and “The 4 hour workweek” and think Tim Ferris is a smart and intuitive guy. I read the 4 hour body multiple times (mainly just the bodybuilding, lose weight etc chapters) and found it eye opening. I believe Tim never states that his methods are the end all, but he does always say ” figure out what works, and get tested.” His sleep chapter is interesting but would never fit into my current schedule. I also don’t think he claims to be an expert in anything he writes about but someone who has experimented enough to make solid judgments. I agree with you though just because it worked for him it may or may not work with everyone.

    • says

      Hi Ray,
      I agree, Tim is a smart guy and has a lot to offer. I do poke fun at him but it is in good spirits that I do so. Glad you feel you gained a lot from his work! I’m not on a crusade to prove Tim wrong but I think investing these claims helps everyone. Personal grudges are an impediment to advancing the health dialog and I have nothing personal against Tim. In fact, there is much that I admire about him.

      However, on the Adam Corolla show he said (paraphrase) “…anyone can cut 6 hours from their total sleep time and still be fully rested.’ I felt this particular claim was exaggerated and prescriptive so I thought I’d explore it further to see where I arrived on the topic. After the next article, hopefully you’ll feel that, overall, I given this concept fair treatment and that you gained something from the discussion!

  5. Alasdair says

    The skepticism bit is interesting, and the idea that anecdotal evidence doesn’t equate to data.

    I’d be interested in hearing from the paleo community of peer-reviewed papers supporting the paleolithic diet (I’ve struggled to find much)

    (I’d like to qualify this by stating that I aim to eat paleo for the rest of my life, and have been doing for three months and feel great)

  6. says

    Great post Dan!

    I remember reading Steve Pavlina’s personal accounts of polyphasic sleep years ago. He maintained the practice for several years but eventually gave it up because he was so *socially* out-of-synch with everyone else. Also … he found that it was incredibly inflexible. If he missed one of the 20 minute naps he would just be useless for the rest of the day.

    • says

      Hey JD,
      Love your blog (Systems for Living Well), by the way . Awesome! I discuss some sleep biology in detail in Part 2. Different systems combined to affect alertness. The inflexibility of the polyphasic sleep design plays with one side of the axis. I may have to follow up to address this “inflexibility” more specifically depending what questions arise.

  7. Tommy McCann says

    I took an interest in polyphasic sleep this summer. I am fascinated by the idea. The most complete study that I could find was Claudio Stampi’s “Why We Nap”. One of the most interesting points he brings up is that monophasic sleep is not normal in nature but almost unique to humans. Infants and people in old age tend to regress to polyphasic sleep or semi monophasic sleep. The report has a lot of data but is anything but conclusive and there isn’t a good study on the long term effects. I have been using polyphasic sleep on and off ever sense.

  8. Newman says

    My boyfriend tried that when he was taking a break from working. He said that at the end of the obligatory month he did it, his body fought waking up during the naps and he constantly felt like he was walking around in a dream.

    We know now that non-REM sleep still is important for memory and brain function, not to even go into how hormones cycle through circadian rythyms that need long periods of rest.

  9. George says

    I did this during 4 years of military flying after college, and before that during my senior year of high school. You will always feel more tired a few days in than if you just got a full nights rest.

    End result was once a month usually sleeping 18-20 hours…straight. Seriously. It ruined many a good weekend because of the sure need to let the brain do its thing.

    A better idea is to get a full 8 hours, follow Robb’s guide to completely blacking out your room and learn to manage your time awake better.

  10. Michelle says

    It wouldn’t surprise me if Tim had done more research on the topic than Dan (just judging by my first impression upon a quick read of this article – though I could be wrong – and I haven’t gotten around to Tim’s book yet so really what do I know in saying this), but either way – I agree that the skepticism is important.

    I got really interested in this in grad school when I was really struggling with sleep. One of the issues I was most interested in was having a non-24 hour wake/sleep cycle (e.g., 24.5, 25, or 26 hours). When I was doing a lot of writing and was more off-the-grid than usual, I tried experimenting with going to sleep when I was tired and waking up when I did so naturally (sans alarm clock) (this also ties in with Robb’s or Mark Sisson’s recommendations to not use an alarm clock – Robb, do you recommend this or just recommend to sleep 8-9 hours/night?) Anyway… when I tried this, I definitely found that I got tired later every night, and woke up later every day. I DID find that, compared to previous experiences where I was constantly oscillating between sleeping not enough (4-6 hours) and sleeping too much (10+ hours) to overcompensate, my sleep time did tend to stabilize at about 8-8.5 hours (and I felt great!). It WAS shifting though, and before I knew it, I was going to sleep at sunrise and waking up mid-afternoon. This happened to me many times throughout school, but this particular instance was my most controlled experiment.

    Of course, at the time, I was spending all day indoors at my computer so wasn’t necessarily getting the appropriate light/dark signals to my brain. I also probably have/had issues with cortisol with being constantly sleep deprived and/or stressed. So, who knows what the ultimate cause(s) were (I haven’t studied enough about cortisol nor sleep in general to have a great hypothesis). Regardless, I’m still intrigued with the idea of a longer wake/sleep cycle because I feel like I’ve constantly battled this issue of wanting to go to sleep later and later each night, if left to my own devices, and have found it very difficult to maintain a routine schedule for this reason, despite numerous attempts to “get back on track.” Is it the sleep deprivation that leads to the cortisol issues and further sleep deprivation? Or is it the longer wake/sleep cycle (and requirement of waking up early for work/school) that leads to the sleep deprivation that then leads to the cortisol problems that then perpetuates a terrible miserable sleep pattern?

    Or, another point I just thought of… it’s a lot easier to sleep at night when one does manual work and/or is outdoors all day (going to the gym for an hour and going for a walk for an hour still does not come close to comparing to spending the day outside hiking or working or playing sports). Society nowadays is not conducive to that type of lifestyle – so do we all have artificially induced longer wake/sleep cycles due to inactivity?

    Needless to say, first coffee, and then melatonin, vastly improved my life. Not ideal, but better than sleep deprivation.

    • says

      I think we are similar in that we both have an elongated circadian rhythm. Back in early 2000, I was having major sleepiness issues. I would be sleepy all day, then right before bed, I’d become alert and would want to stay up late. I would cycle into this pattern frequently. This lasted for years and really affected the quality of my life, which got me interested in sleep. Eventually, I was able to conquer this issue, not with drugs, but with light. I take a walk first thing in the morning with my dogs, which helps anchor my circadian rhythm. Also, many people view how to use melatonin in a less-than-optimal way but I’ll save that for another time. It would make for an useful post, I think.

  11. Martin says

    An interesting read.

    Dan, could you cover a little bit the topic of ‘sleep supplements’ like 5-HTP or melatonin?

    Also, I’d be interested in your opinion on the T.S. Wiley’s book. Some of her ideas seem spot on, others appear a bit controversial. What is your skeptical view of that book?

    • says

      Hi Martin,
      I’d be happy to cover pharmacological treatment of sleep, including supplements in the future.

      Regarding TS Wiley’s book. I have not read it. I did read the first chapter but then put it down. If you have any specific questions, I’ll be happy t address them, not as a review of her perspective, rather, from how I view the subject. Cool?

  12. Steve says

    Tim Ferriss has made so many outlandish claims that I have a hard time taking his work seriously. His contention that he gained 34lbs of muscle in 28 days is particularly hard for me to believe. He claims to have gone from a weight of 146 to 177, while also losing 3 pounds of fat. Of course, he achieved these results working out for 30 minutes twice a week, and doing almost no compound lifts (he did include dips, rows, and leg presses), and using a one-set-to-failure protocol. Maybe I’m stuck in a conventional bodybuilding wisdom mindset, but that seems basically impossible to me. When Rippetoe claimed that his trainee gained a similar amount of muscle over almost three times as long (31lbs in 11 weeks) and also getting fairly fat (24lbs of fat gain), many people had a hard time believing that. And his trainee squatted heavy 3x/week and drank a gallon of milk a day.

    If Ferriss is willing to stand behind claims like this, I have to question the veracity of his whole body of work. It’s a shame, because he seems like a smart guy with a lot of interesting perspectives. If anyone has evidence in favor of Ferriss’s weight gain program, or a different perspective on this, I’d love to hear it.

  13. says

    I did polyphasic sleep for 9 months next year, 2 months on 2 hours a day and 7 months on 4 hours a day. I found it to be pretty much a total success, but my wife eventually put the kibosh on me being up most of the night. I went from 4 hours to 9 hours and I can say this for sure: a regular 9 hours and a regular 4 hours are both MUCH better than an irregular “several” hours a day of whatever I can grab.

    • says

      Hey Justin,
      It sounds like you feel that getting consolidated block of sleep was more restorative than spreading your sleep into segments across the day, regardless of total sleep time in a 24 hour period. Am I right? How long did you try a split schedule vs reduced and elongated consolidated schedules?

  14. Liane says

    I sorta involuntarily tried this and it was an abysmal failure. In fact, during the time I did it I gained 20 lbs.

    Here is what happened. I was working the PM Shift (3-11) for years on a busy cardiopulmonary step down unit when I got the chance to take a job in cardiac care. Only problem it was on nights. I was exhausted when I got home but had to get my daughter off to school, and then I went to bed for as long as I could sleep. I got up at about 2 and then dealt with life. I did not know when to eat so I basically grazed through the day. Not good. After the family was all settled in I went to bed with my husband, but set an alarm, got up and did the whole thing again. It was hell. I was so stressed and sleep deprived that I actually developed a very serious heart arrhythmia. One of my doc friends found me hooking myself up on a monitor, and took over, and in the course of a few minutes we silently watched the screen as I threw three PVCs in as many minutes. I was 35, healthy as a horse, lean but getting fat. He told me to quit and I did. I do no think some people can ever adapt to working nights and not getting 8 contiguous hrs.

    A little lidocaine and a few days at home sleeping at night like I was intended to fixed me.

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