Science of polyphasic sleep
- 1 Warning
- 2 The law of accelerating returns
- 3 The Uberman's Sleep Schedule
- 4 Polyphasic sleep
- 5 To sleep or not to sleep polyphasically
- 6 5 years since the Uberman Big Bang
- 7 Compression of sleep stages in sleep deprivation
- 8 Sleep and creativity: Less is more
- 9 Polyphasic sleep in babies
- 10 Ultradian oscillations in babies
- 11 Do Piraha people sleep polyphasically?
- 12 Polyphasic sleep: scientific challenge
- 13 Charting polyphasic sleep
- 14 Claudio Stampi
- 15 Sleep deprivation is like alcohol intoxication
- 16 Sleep debt and napping
- 17 Polyphasic geniuses
- 18 Sustainability of polyphasic sleep
- 19 Caffeine in polyphasic sleep
- 20 Polyphasic sleep mutants
- 21 Polyphasic sleep blogs
- 22 References
The law of accelerating returns
We live in the times of accelerating acceleration. The Moore's Law makes the world smaller, faster, more connected and more efficient. We are now able to touch and feel Kurzweil's generalization: the law of accelerating returns. The fast-living young generation is hungry for more. More fun, more information, more accomplishment, more education and... more waking time. It is pretty amazing to see how many people will lean over backwards to shorten their sleep to increase productivity. Young self-experimenters keep cutting sleep short with alarm clock, using controlled substances, pulling regular all-nighters, or trying to use the sleep time for "useful purposes" (e.g. learning in sleep).
In a blog of a young entrepreneur attempting to save time by sleeping less, I read (boldface emphasis is mine):
Sleep is not my friend. As a budding young entrepreneur I have a desire to go about life with less sleep and more waking moments in life. I always feel like those moments in bed are moments that could be used for a more noble purpose. [...] As any good Industrial Technologist knows for something to be controllable it must be measurable. So I wrote down the time I went to sleep and time I woke up every morning for a year. Measuring it gave me a good benchmark to improve upon
A praiseworthy one-year record of measurements followed and produced a nice graph of healthy and regular sleep averaging an enviable 8 hours per night (slightly less in summertime). A sleep expert might exclaim: "Good for you! Keep it up!" But a budding entrepreneur goes on to "improve upon" millions of years of evolution:
This is a total of 112 days asleep and 253 days awake. Or, to put it another way, I slept away 31% of the year, [...] I tried a few experiments with my day to see if I could reduce the time I spent sleeping. For example, I once tried strictly limiting my sleep to 5 hours each night … it lasted about 2 weeks and I gave myself a fever. Then I tried pulling an all-nighter once a week for as many weeks as I could manage. That did not last long either. Most notably because the 2nd day after the all-nighter was always so unproductive that the extra time I was awake did not produce a net increase in my productivity. [...] I have yet to find a good way to sleep less on a consistent basis
I wonder why a good Industrial Technologist did not bother to spend 5 min. to google for the function and the noble purpose of sleep. After all, you do not need an honors degree in biology to know that if the body does something, it is nearly always for an important purpose.
In addition to the said hunger for more productivity and more waking time, the myth-making power of the human mind is now grotesquely amplified by the all-mighty Internet. If there is an idea that could make life better or more bearable, it quickly takes on its own Internet life as soon as it is invented. Along the rules of the memetic science, the idea grows, mutates and evolves. It feeds freely on science as well as on rumor, self-experiment, and unscrupulous sources biased by self-interest ready to trade truth for profits. It snowballs adding new pleasing facts and hypotheses as it rumbles over the unprepared minds. Like a new messiah, it drags behind new followers, advocates, apostles and die-hard guerillas ready to contribute to the ultimate victory of the cause.
Around the year 2000, a new meme cropped up in several blogs on the net: The Uberman's Sleep Schedule. Due to my interest in the role of sleep in memory and learning, it did not take long for the meme to hit my inbox. As the concept kept ballooning on a monthly basis, it left me with little choice but to take a stand. My original article from 2005 can be found here.
The Uberman's Sleep Schedule
The idea behind the Uberman's Sleep Schedule is to gain waking hours by sleeping the total of just 3 hours in 6 portions distributed equally throughout the day. There are many variants of the scheme proposed by those who tried to sleep along the schedule. The schedule is supposed to compress physiologically less important stages of sleep and homeostatically upregulate stages vital for mental health. The Uberman's Sleep Schedule was proposed in this blog at Everything2 by a woman hiding behind a nick PureDoxyk. The blog reported a sleep experiment with an innocent admission that the Uberman schedule was incompatible with the experimenter's schedule and goals. Yet the meme was picked up in a Kuro5hin article in 2002. Phrased in a simple and well-structured language, this time it was noticed. Again, the post ended with "Uberman's sleep schedule is a potentially dangerous way to increase your waking hours". That did not prevent a frenzy of new followers ready to gain years of waking time. The catchy theme of the concept is that, indeed, if you succeeded in sleeping 3 hours per day instead of the prescribed 8, starting at 20 years of age, you would gain over 11 years in an average Western lifespan. The idea is very attractive. No wonder then that as such it seemed to keep gaining momentum for quite a while.
With increasing frequency, Uberman's Sleep Schedule was being referred to as polyphasic sleep, a term popularized by research and book by an Italian chronobiologist Dr. Claudio Stampi. Polyphasic sleep is known to sleep researchers as a variant of a sleep pattern that is set in opposition to monophasic or biphasic sleep. In monophasic sleep, an individual or an animal sleeps in a single block during a single wake-sleep cycle of 24 hours. In natural biphasic sleep, there are two blocks of sleep in 24 hours: the night sleep and the typical Latin siesta.
Polyphasic sleep is quite widespread in animal kingdom. In a recapitulation of phylogeny, human babies also sleep polyphasically, and gradually lose their napping propensity until they become roughly biphasic around the age of one. Human adults, as much as all great apes, are largely biphasic. Although a majority of westerners do not nap on a regular basis, their alertness shows a slump in the middle of the subjective day. This slump can consolidate in a short sleep episode in free-running conditions.
The theory behind the Uberman's Sleep Schedule is that with some effort, we can entrain our brain to sleep along the ancient polyphasic cycle and gain lots of waking time on the way, mostly by shedding the less important stages of sleep (e.g. shortening Stage 1 of NREM, which seems to be just a transition state to the more "useful" stages of slow-wave sleep). That theory is flawed as it does not take into the account the magnitude of the circadian acrophase in the subjective night.
To sleep or not to sleep polyphasically
Having presented polyphasic sleep as seen by its enthusiastic advocates, let us have a look at its physiological roots and implications. With every passing month, we accumulate a tremendous body of evidence of the vital role that sleep plays in memory and creativity. In addition, most of us have a good understanding that without sleep there is little chance for an intellectual accomplishment. Even more, we find it hard to stay awake unassisted for longer than 2 days. Although, super-human achievements have been well documented, where people like Peter Tripp (1959), Randy Gardner (1965) and Tony Wright (2007) stayed (semi-)awake for 8, 11, and 11 days respectively, most of mere mortals cannot even suffer through the first 48 hours of wakefulness and inevitably fall prey to slumber. EEG and actigraphy measurements indicate that humans are basically biphasic. There is a single powerful drive to sleep during a subjective night, and a single dip in alertness in the middle of the subjective day. EEG measurements are confirmed by many other physiological variables such as temperature measurements, cortisol levels in the blood, melatonin levels in the saliva, levels of other hormones, blood pressure, gene transcription, immune cell activity, subjective alertness, and countless other parameters. In 2007, I have finally been able to see the same effect in the circadian changes in memory recall and consolidation in SuperMemo. At the root of human 24h periodicity is the activity of the suprachiasmatic nucleus (SCN) in the brain, which is driven by a 24 hour cycle of gene transcription changes running a classic feedback loop. Tiny mutations in the genes responsible for the circadian periodicity may lengthen or shorten the period of the circadian cycle. They can also lead to complete arrhythmicity. Many of such mutations have been studied in fruit flies and in mice. Human mutations leading to sleep phase disorders are also known (e.g. familial ASPS). However, those mutations are rare, and for a vast majority of healthy humans the length of the period is slightly longer than 24 hours. Dr Charles Czeisler has measured it to be 24.2 hours with amazingly little variation among individuals under the conditions and within the sample studied (Czeisler et al. 1999). The circadian cycle (incl. the gene transcription and the activity of the SCN) can be prodded and shifted slightly on a daily basis. The degree of the shift is determined by the phase response curve (PRC) and requires a very precise timing of the phase-shifting stimulus (Khalsa et al. 2003). In other words, with a stimulus such as light, physical activity, or social interaction, we can move the period of maximum sleepiness slightly. Although the precise measurements of the PRC speak of the possible shift of up to 3 hours in a single day with a single strong stimulus, it is hard, in practice, to shift one's circadian rhythm by more than 1 hour per day. We all get a little backward prod daily when we try to fit the 24 hour day. This daily resetting is painless for those who apply the principles of sleep hygiene. It occurs in the morning with light, activity, and/or stress. An increasing portion of the population use the alarm clock to do the job that should naturally be done by sunlight and activity. This is not a healthy solution and is usually forced by our electrically-lit lifestyle with evening TV, evening reading, evening Internet, evening partying, etc. For those out of phase, it is easier to shift the sleep schedule to later hours (e.g. by activity late in the night) than it is to shift it back (e.g. by bright light in the morning). This asymmetry comes from the fact that we can consciously control the waking hours, which can only be used for a forward shift. It is easy to will oneself to stay up late. It is far harder to will oneself to wake up early. Naturally, an alarm clock can be used to accomplish the latter, but use of alarms should be avoided in chronotherapy and in healthy sleep due to disruptive effect of alarms on the progression of sleep cycles. While it is possible to shift the sleep phase, we do not know any biological mechanisms that could be used to significantly reduce the length of a healthy sleep block without inducing a degree of sleep deprivation. Shortest effective sleep can be accomplished on a free running sleep with strong morning resetting stimuli and strong evening phase delay stimuli. However, even natural stimuli can induce a degree of sleep deprivation. Shifting the sleep phase has a relatively small effect on the length of the main sleep block. The change is proportional to the degree of shift and has the same sign (i.e. shift delays reduce the length of subjective night sleep). Most importantly, the change reverts to the baseline shortly after the shift. This illustrates the homeostatic nature of sleep control mechanisms that respond to phase-shifting stimuli by stabilizing the new sleep schedule at the new offset within a very short time as long as shifts are small enough and are generated by well-timed phase shifting stimuli. A more decisive intervention in the sleep patterns may result in circadian chaos. In Siberian hamsters, it can even cause arrhythmicity (Ruby et al. 1996). Those dramatic changes can have a serious health effects and may be difficult and slow to reverse.
The well-defined effects of natural stimuli that affect sleep patterns lead to an instant conclusion: the claim that humans can adapt to any sleeping pattern is false. A sudden shift in the schedule, as in shift work, may lead to a catastrophic disruption in sleep control mechanisms. 25% of North American population may work in variants of shift schedule. Many shift workers never adapt their sleep pattern to the shift pattern. At times, they work partly in conditions of harmful disconnect from their body clock, and return to restful sleep once their shift returns to their preferred timing. At worst, the constant shift of the working hours results in a loss of synchrony between various physiological variables and the worker never gets any quality sleep. This propels an individual on a straight path to a volley of health problems, which include cardiac disorders, suppression of the immune system, diabetes, gastrointestinal disorders, obesity, depression, chronic fatigue, sleep disorders, etc. Shift-workers are also at a higher risk of accidents and family problems (e.g. experiencing higher divorce rate). Shift-work design should apply the laws of chronobiology to minimize the adverse effects of shiftwork on health. It is often better to keep workers working by night on a constant basis than to induce a regular sleep disruption and stress on a weekly basis by a cycle of never-ending schedule shifts. It appears that polyphasic sleep encounters the precisely same problems as seen in jet lag or shift-work. Adult human body clock is not adapted to sleeping in patterns other than monophasic or biphasic sleep. In other words, the only known healthy alternatives are:
- a single 6-8 hours sleep block in the night, or
- a night sleep of 5-7 hours combined with a 15-90 min. siesta nap. Those numbers differ substantially across the population and there is no single recommended dose of sleep for everyone.
If a degree of pressure is exerted on the body clock, e.g. by going to sleep later than the body's optimum, the mid-day nap may serve as a compensatory buffer counteracting sleep deprivation. In such conditions, the nap may last longer than the usual 15-30 minutes. The more pressure is applied on the night sleep, the longer the siesta nap. Similar biphasic consolidation can also be produced experimentally in rats. It appears that with sufficient pressure the nap may become longer than the night sleep, effectively reversing the sleep pattern by 12 hours. This effect confirms an important biphasic nature of the human sleep that is not fully accounted for by the present sleep models. In rare cases, individuals may learn to sleep in two blocks of 3-4 hours. However, in a vast majority of cases, the pattern in which sleep occurs in two equal blocks within 24 hours in unstable. In other words, individuals on the proportional biphasic schedule quickly fall back to long-night sleep and short siesta sleep, or back to monophasic sleep. Often, the portion of sleep that occurs during darkness takes the role of the night sleep. However, it is more likely that this role is taken by that portion of sleep that was longer before the establishment of the proportional biphasic pattern. This again indicates the underlying physiological asymmetry between two sleep blocks in a biphasic pattern. In other words, the body remembers which sleep block is the subjective night block, even if that block happens to occur during the daylight period. Through sleep deprivation, by employing the homeostatic component of sleepiness, polyphasic sleepers can increase the number of naps during the day. However, the pattern of one night sleep and multiple daily naps is highly unstable, and can be maintained only with a never-ending degree of sleep deprivation. Naturally, if you happen to use an alarm clock, you can easily run multiple "naps" during your circadian low-time during the subjective night. This is not possible during the subjective day (except in conditions of extreme sleep deprivation). To a degree, an alarm clock can also be replaced with your internal alarm (e.g. thinking "I must get up in 20 minutes"). None of "naps" executed in similar conditions will do the job of natural sleep. They are not only largely a waste of time, but they also contribute to dismantling your sleep control mechanisms. Dr Stampi's research on polyphasic sleep has also clearly identified the forbidden zones for sleep where naps are very difficult to initiate without substantial sleep deprivation. Those zones map well on the biphasic rhythm with the subjective evening naps preceding the core night sleep particularly ineffective for rested individuals. All the above findings inevitably lead to a conclusion that it is not possible to maintain a polyphasic sleep schedule and retain high alertness and/or creativity! As it will be shown later, practice is no less lenient in judging the impracticability of polyphasic sleep for creative individuals.
Anecdotal evidence seems to indicate that highly creative individuals perform best in a biphasic sleep pattern. However, the only valid rule of a thumb for maximizing creativity and alertness is to sleep then and only then when you feel sleepy. When this rule is applied, individuals may fall into a number of diverse schedules. They might be quite effective in any of these exemplary mono- and biphasic patterns: typical 7+2 or 6+1, long sleeper's 9+0, short sleeper's 4+1, or even 4+0, etc. Only you can determine which schedule is optimum in your case. However, you can expect that if you are a normal healthy individual, this schedule will not be polyphasic (other than biphasic). If you attempt 3+0.5+0.5+0.5, you will either be seriously sleep deprived (i.e. you will maintain the schedule only with the help of an alarm clock), or you will revert to 3+0.5, or more likely, you will fall back onto a standard 6+1 pattern. The possibility of hooking up your naps to the ultradian rhythm without sleep deprivation is a myth.
5 years since the Uberman Big Bang
In the years 2002-2005, I noticed an exponential increase in the interest in the Uberman Sleep Schedule. I kept receiving more and more mail with questions about the impact of Uberman on health and learning. As a result, I wrote Polyphasic Sleep: Facts and Myths. In the course of the five years that followed, I received some 500 pieces of mail and got in personal touch with many polyphasic sleep adepts. Of those attempts that I was given a chance to monitor, all were unsuccessful. Some of the critics of the original article claimed that they do sleep polyphasically, but I received no data that could serve as the basis for verification. The most interesting conclusion coming from the mass of mail received is that people drift towards polyphasic sleep less as a result of their hunger for achievement, and more for their prior problems with sleep. They often think of polyphasic sleep as a panacea for all their sleep problems. This perception is magnified by multiple blog claims. I received a couple of SleepChart data submissions demonstrating how difficult the struggle with the polyphasic sleep is. Admittedly, I was quite impressed with the degree of determination some of those experimenters showed. As the newest version of SleepChart makes it possible to model the changes in sleep propensity, it provides some insights into the phase-shifting chaos that occurs in polyphasic sleep. With every passing day, we know more about polyphasic sleep and its potential impact on health. The news is not good for the proponents of the polyphasic sleep as a lifestyle.
The mail that I have received in reference to my polyphasic sleep article was mostly critical, but it should not be used as a measure of success. It is not important what proportion of readers would agree with me. It is important how many gave up the idea of sleeping polyphasically as a result. Within the five hundred pieces of mail, I roughly estimate the distribution of their nature as follows: 50% - criticism, 40% - requests for help in implementing polyphasic sleep, and 10% - word of gratitude for the warning against adopting polyphasic sleep. 10% may seem like a very low conversion rate. However, this translates to hundreds of hours of someone's time. I am sure it also translates to tangible health benefit. For example, a great deal of polyphasic attempts end up with a cold or influenza, which must reflect the impact of this sleep schedule on the immune system. What Aaron wrote is pretty representative of the 10% group:
The idea of sleeping in naps spread throughout the day intrigued me as I have always suffered from what I was unable to properly quantify, but now know is DSPS. If I do not use an alarm clock, and go to sleep when I become tired, I see my sleep/wake times shift to significantly later times every day (hours later). This has been a constant source of frustration for me, and I considered a polyphasic schedule in order to help correct the problem. However, after reading "Polyphasic Sleep: Facts and Myths", I have decided this would be a sincere waste of my time
Criticism of my article would usually skirt around the science argument and quote from blogs of people who claim they have succeeded with polyphasic sleep. For example Kop wrote: "There are MANY people who successfully adapted. [...] You simply neglected to cite them, and you cited only people who failed. I think this is very unfair and misleading to your readers. I may sound like a broken record, but even if you believe that everyone who claims to have been successful is lying you should let your readers make this choice and you should definitely not just completely leave out all the information you personally don't agree with".
Compression of sleep stages in sleep deprivation
One of the myths of "Uberman sleep schedule" is that it makes it possible to enter REM sleep and skip non-REM sleep stages entirely. That myth is derived from another false claim that implies a non-essential role of deep sleep. I will ignore these claims as standing in total disagreement with laboratory findings. Instead, let us focus on a more plausible claim of the possibility of compressing sleep stages in polyphasic sleep. It is true that people who are sleep deprived are able to enter deep sleep much faster than normal sleepers. After a period of sleep deprivation, less important stages of sleep are compressed, while the core SWS predominates. Also REM deprivation will result in REM upregulation at recovery time. Initially, the sleep system will work on catching up with the outstanding SWS, and only later with the outstanding REM sleep (often only on a second recovery night). It appears then that indeed, we are more effective at sleeping after we had been sleep deprived. Moreover, it is possible that the homeostatic control of sleep is not very efficient at detecting the true neural sleep needs. If you look at our mammal relatives, you may be surprised that a giraffe can do well on 2 hours of sleep, while a bat may need 20. Smart and fast-learning elephants need 4 times less sleep than less brainy felines. Behavioral observations will then quickly lead us to the conclusion that the amount of sleep is not directly correlated with the amount and complexity of memory acquisition and neural computation. We may then hypothesize that the sleep control may employ auxiliary physiological parameters that are only loosely related to the requirements of neural optimization. It is also possible, that evolution took account of the fact that the nighttime is not a very useful time for activity in early hominids. Sleep control mechanisms might then have attracted a number of additional physiological functions that might improve survival even if sleep lasted longer than what is needed for memory consolidation and optimization. Hence the possibility of all sleep mechanisms proceeding at leisurely rate with lots of added function that would not require loss of conscious awareness in the first place. If the above thinking is correct, we might indeed be able to execute the same neural job in a shorter time given the favorable circumstances. However, little is known of the true nature of the link between neural optimization and homeostatic sleep control. Our present knowledge still seems to firmly indicate that we can maximize our creativity to sleep cost ratio only with free running sleep. In other words, there is no evidence that by playing with sleep deprivation, you can increase your creativity. The only possible exception might be a tiny degree of deprivation resulting from delaying sleep by 30-60 minutes. Longer delays affect alertness beyond what might be considered a "gain". It is simply possible that between the extremes of free running sleep and a slightly delayed sleep phase, the trade-off between (1) time gain due to sleep compression and (2) an accelerated homeostatic sleepiness might produce an optimum somewhere in between. Naturally, this tiny prod to a sleep cycle has nothing to do with the employment of alarm clocks, shattered schedule and never-ending battle with grogginess typical to those who experiment with Uberman sleep. Moreover, even that little hypothetical intervention in the sleep cycle will inevitably result in phase shifts that may have numerous negative side effects, including, most obviously, the inability to function effectively in a society that is largely synchronized with daylight. Well-entrained and balanced free running sleep is still your best bet for maximum cognitive performance.
In sleep deprivation induced by polyphasic schedules, REM sleep will occur faster due to sleep stage compression. Yet it is the slow-wave sleep that is the primary target of homeostatic upregulation strongly determined by the duration of prior waking. As REM sleep is far more associated with the circadian phase, its proportion in sleep will actually drop, esp. in naps initiated in the subjective evening period. You may want to study sleep models by Alexander A. Borbely and Peter Achermann which nicely explain the mechanics of these processes. Laboratory findings seem to indicate that the drop in REM gradually recovers towards the baseline over successive days of sleep deprivation, but the reversal is never complete. In other words, you will get less REM sleep on a polyphasic schedule as compared with a free running schedule. This REM sleep diet is as much absolute (as measured in minutes) as it is relative (when compared with deep sleep NREM). The problem of REM deprivation becomes more pronounced if you use an alarm clock when waking up from naps. By using the alarm clock, you statistically hit REM sleep more often as its proportion nearly always increases over sleep time. This is why polyphasic sleepers often remember their dreams on awakening. That's not a sign you get more REM. It's a sign you are destroying REM sleep. By using very short blocks of sleep, you affect REM even further by a strong homeostatic upregulation of Stage 4 NREM that displaces whatever REM you can get.
If you (1) do not fight sleepiness and (2) wake up from your naps naturally, the problem of sleep disruption does not occur. However, it is impossible to regularly fit a pre-planned polyphasic schedule without some help from an alarm clock. This comes from the fact that the only stable sleep patterns in healthy individuals are mono- or biphasic. Polyphasic sleep patterns may be stable and sustainable in various cases of hypersomnia, narcolepsy, and other sleep disorders. When the sleep control system is disrupted and the homeostatic sleep component works in overdrive, frequent napping may occur and be recommended (e.g. in infection, chemotherapy, etc.). Needless to say, the total sleep increases in such circumstances. This is exactly what polyphasic adepts are trying to avoid. A degree of sleep fragmentation may also occur as a result of stress, social life, excitement, going to sleep too early, etc. Those disturbances may occasionally allow for days with more than one nap occurring naturally. If you give up the alarm clock, you take away the major culprit that makes polyphasic sleep unhealthy. However, without an alarm clock, it is your body that will decide the sleep schedule, not your pre-planned "rationalized" schedule graph. That schedule will not resemble anything Uberman.
Sleep and creativity: Less is more
Polyphasic sleep is bad for your health and bad for your creative capacity. However, even if you want to maximize time spent in the waking state it might not be your best option assuming you need a reasonable degree of alertness for whatever you do in your waking time! Only when approaching substantial sleep deprivation can polyphasic schedule be superior to biphasic schedule in that respect (see: PureDoxyk Law).
Some people like firefighters or emergency surgeons may sacrifice their sleep for the sake of others. The number of people that need to make a sacrifice can be reduced by a well-designed shiftwork. Most of the remaining population should optimize their sleep for best health and best creative performance during the waking time. Polyphasic sleep is definitely not the answer to such optimization goals.
These are not the times of the pyramid of Giza when the genius of a designer had to pair up with 50,000 drudges reduced to mere back-breaking labor. As we move towards the knowledge economy, it is the alert and creative minds that provide the basis of success in most projects. One minute of insight may be worth a century of shoveling! It might have been a single creative eureka that produced E=mc2. Probably even Einstein himself would not be able to track back the exact moment when his brain produced that formula. Nor would he be able to formulate a sure prescription for others for similar accomplishments. Human creativity is primarily a game of chance. Yet it breeds only on fertile grounds. Top-notch mind in a top-notch shape in conjunction with top-notch sleep is the best formula for more of such insights in the future. Polyphasic sleep is the antithesis of that formula! If you scan the blogs of polyphasic experimenters you will see them choose an "engaging activity" again and again just to stay awake. Why would they prefer to meet people or go for a jogging over, for example, getting down to a mentally challenging project?
Tony Wright in his attempt at Guinness Record of sleep deprivation (11 days without sleep) realized that he could do anything but writing. After 10 days without sleep, his brain was not up to the challenge of writing even a couple of words. He concluded: As it turns out writing while sleep deprived is easily the most difficult thing to do, for that reason I have decided I won't write anymore, so this will be my last entry.
Why would learning a difficult subject be such a mental drag in sleep deprived state? As sports or social interactions stimulate the aminergic arousal centers in the brain, these are effective counterweights to the homeostatic drive to sleep. The brain uses its last resources to mobilize the lesser used portions of the cortex to compensate for overloads in the hippocampus and other central memory areas. Creatively, you may be brain dead, but you will still be able to meet people or go for a jogging.
Learning is a powerful contributor to the homeostatic sleepiness. Soporific power of learning is one of the most visible connections between sleep and memory. If you have problems with falling asleep, nothing serves as a better natural hypnotic than learning! Not just passive reading. Active learning! The best homeostatic sleeping pill I know is incremental reading. Naturally, you need a circadian component of sleepiness for the "pill" to work. Otherwise, learning (or incremental reading) is, paradoxically, your best "creativity pill".
There may be more at stake though than just alertness, creativity, and long-term health. It is conceivable that the sleep control centers in the brain become affected by polyphasic experiments. Researchers have noted cases where shift-work or other forced schedule patterns were able put the body clock out of kilter. Some have speculated that Peter Tripp suffered long-term consequences of his awakeathon. Polyphasic schedule is less drastic in terms of sleep deprivation, but more drastic in circadian disruption. Dr Stampi has put one Francesco Jost through a diet of 3 hours of sleep for 2 months without measurable adverse effects. Yet, looking at other neuropathophysiological processes, we might worry that it might be possible to actually kill cells in the nuclei responsible for the SWS switch, REM-on switch, REM-off switch, etc. We know that disregarding mental hygiene, depression, excessive cell activity, glutamate, cortisol, hypoxia, and other neural stresses can lead to cell loss. We know that it is possible to uncouple the circadian cycle in Siberian hamsters with light stimuli (Ruby et al. 1996). As long as this area remains gray, playing with one's sleep schedule is tantamount to dicing with one's long-term ability to effectively control sleep-wake cycles. This might be not much different from dieting, once you put your appetite control centers out of service, you are sentenced to a lifelong struggle with diets and yo-yoing weight. Recent research shows how junk diet causes glial damage to brain centers that control the appetite (Szwartz et al. 2012). I bet that chances are very high that junk sleep will cause loss of effective sleep-wake control. The mechanism is the same: when you put a brain center in overdrive, you risk injury. We can see the same mechanics in a dozen of physiological contexts. Some polyphasic adepts reported sleeping differently after their experiment ended. Some of those reports could hint at the flattening of the circadian cycle, which is a characteristic of sleep control in the elderly. In conclusion:
Why less is more? Because by giving your brain as much sleep as it wants, you can be far more creative and productive in your waking time. Not just far more. In a polyphasic sleeper, the creativity may dip by an order of magnitude. It's like with top performance sports. Wrong timing of meals could deprive Usain Bolt of his Olympic Gold. Do not let yourself be marginalized in the race for intellectual excellence!
Polyphasic sleep in babies
Newborns sleep polyphasically. Clock genes start cycling already early in development in utero. First circadian rhythms also start showing in utero and are entrained to mother's circadian cycle (e.g. kicking, breathing, heart rate, etc.). However, the circadian sleep-wake cycle develops only after birth. The SCN keeps growing at a very fast rate after birth. For example, it contains only 13% of the adult numbers of vasopressin expressing neurons (Swaab D.F. et al. 1990). A hypothesis says that it is the connection between the visual system and the SCN that develops only after birth (Swaab et al. 1994). Research conducted in premature baby wards shows that moderate dark-light cycle accelerates the development of the circadian rhythms, while constant light has an opposite effect, incl. slowing the overall child growth and development (Mirmiran et al. 2000). There was even a report of a full term baby that did not develop a circadian cycle in the period of study, possibly due to the fact that it was the only infant fed in full light during the night (McMillen at al. 1991). Immaturity of the SCN and its afferents in newborns results in their inability to entrain their cycles to daylight in the first month of postnatal life. In the meantime, some preference to sleeping in the night might be related to cycles entrained in utero and/or postnatal entrainment to breastfeeding and mother's cycles, incl. co-sleeping.
Some proponents of polyphasic sleep claim that baby sleep is the most natural way of sleeping and that babies lose it early in life due to their social training. The opposite is true. Newborns show no discernible circadian preference in their sleep patterns. Those patterns develop quickly over the first 1-3 months of life, and have little to do with training. The development of the typical biphasic circadian rhythm is a biological process that is programmed in the genes and is largely inevitable in normal lighting and normal social setting.
In addition to propagating the "social training" myth, proponents of the polyphasic sleep overlook the fact that babies sleep for far many more hours than the alleged polyphasic sleepers (say, 10-16 hours instead of the desired 3). A healthy individual cannot possibly keep sleeping polyphasically, nor sleep for 16 hours, unless in a state of serious sleep deprivation. Babies do not use alarm clocks to control their sleep timing (except their hunger alarm). See an exemplary graph of a newborn polyphasic sleep in the first month of life to notice that sleep episodes come irregularly as a result of a confluence of various homeostatic factors:
In healthy babies, the two primary homeostats that control sleep onset are sleep and feeding. Needless to say, there is no sign of the regular Uberman pattern. If there are ultradian cycles, they are poorly expressed and difficult to filter out. On the other hand, it is possible to see a set of slowly emerging circadian preferences, esp. with sleep episode consolidation. In the presented example, the density of sleep episodes is higher in the 22 pm - 5 am bracket (see more in the next section).
Last but not least, polyphasic sleep advocates, despite a widely circulated polyphasic myth, lose REM sleep in the first order. Babies, on the other hand, may spend as much as 65% of their sleep in REM, without which their cerebral cortex would not even develop correctly (as evidenced in sleep deprived kittens (Stryker et al. 2001)).
Ultradian oscillations in babies
Circadian graphs in SleepChart can be used to seek ultradian rhythmicity in the polyphasic phase of sleep in infants. The presented graphs, corresponding with the first 7 weeks of life, show no clear ultradian oscillation, even though peaks in intervals that are multiples of 3 hours constitute 75% of all peak intervals:
The red circadian line is rather flat, but, as it can be seen in the third graph, some preference for evening and night sleep can be demonstrated with consecutive adjacent sleep episode consolidation:
Do Piraha people sleep polyphasically?
While scientists do not know any natural biological mechanisms that could be practically used to reduce the length of sleep episodes without a detriment to health, Daniel Everett's field report on Piraha people claims that members of the tribe rarely sleep more than 2 hours per day. We know of unhealthy ways of reducing the length of sleep. We can hormonally reduce the length of sleep (e.g. by stress). We can use an alarm clock. That includes the natural brain clock based on the release of ACTH. We can sleep in a wrong phase. We can reduce the homeostatic sleep drive (e.g. with coffee, drugs, exercise, etc.). All unnatural ways of shortening sleep time will induce sleep deprivation, which is a function of the degree of the interference with sleep. The net is buzzing with anecdotes about the merits of the polyphasic sleep, but no established scientific fact can be used to assert that sleep length can be reduced. The example of Piraha people should certainly be of interest for sleep science. However, the inaccessibility of the tribe leaves little room for research beyond a speculation on a report by a missionary. A report could be a simple exaggeration. Piraha people could also be an example of the dominance of culture over physiology (as it is the case with the "polyphasic sleep" crowd). We know of many mutations that affect circadian cycles, and it is conceivable to see a strong prevalence of a specific gene in an isolated population. However, this would make Piraha sleep depart far away from the standards well established in our primate group.
Polyphasic sleep: scientific challenge
I keep garnering criticism for my pop science writing on polyphasic sleep. However, little of that criticism addresses the basic premise that makes it easy to predict that polyphasic sleep cannot be used as a plausible lifestyle choice. I am therefore at a point where I need to ignore the criticism unless it addresses that basic scientific premise:
In practise, the above premise means that only monophasic and biphasic sleep patterns are healthy and recommended. I consider segmented sleep a variant of ancient monophasic sleep induced by periods of prolonged darkness. All forms of nocturnal waking are a norm and should be considered part of the nighttime sleep episode. The choice between mono- or bi-phasic sleep will depend on the circadian wave function, which has two minima in a 24 hour period, only one of which has been proven essential for health and well-being (until now).
Are early risers better at polyphasic adaptation?
Early risers will suffer in polyphasic sleep as much as owls. The chronotype does not matter. People suffering from irregular sleep-wake rhythm characterized by a loss of the circadian cycle do nap at irregular intervals but they neither feel energized nor sleep less than healthy individuals. Neither early risers nor owls nor short sleepers can adapt to a regular polyphasic schedule. Polyphasic sleep can save lives in conditions where vigilance is in demand, but it will also shorten lives of those who are forced to practise it.
Why so little research into polyphasic sleep?
From anecdotal evidence I can conclude that polyphasic sleep is not sustainable enough to do much damage. However, it also helps perpetuate lots of catchy myths that may affect how young people approach sleep and health in general. Sleep myths often target increased creativity, physical strength or increased libido. Polyphasic sleep is not a neat study subject. Scientists like simplicity. They construct simple research models to make it easier to arrive at valid conclusions. I, for one, love free running sleep concept as a research model. It speaks of unadulterated natural healthy sleep. I wish more researchers paid more attention to free running sleep condition as all forms of laboratory designer schedules introduce a degree of chaos into data that very often makes it hard to interpret it or leads to a false interpretation! Polyphasic sleep was suggested for unnatural survival situations, and its Uberman variant is a widely mutated invention of teenagers who hope to save time on sleep or solve their sleep problems. Choosing a polyphasic sleep as a model would be like choosing a multiplanet system to test Newton/Keppler's laws, while a two-planet system would do as well and produce results eons earlier. Instead of a complex Fourier analysis, we have simple and clear formulas that tell the entire story.
Medical supervision of polyphasic sleep
Some polyphasic adepts keep wondering if it wouldn't make sense to make regular checkups at their doctors to avoid potential health hazards of a polyphasic sleep schedule. The problem is that a family doctor's ability to detect trouble on polyphasic regimen is not much different from his ability to see trouble in a novice smoker. The damage is not done instantly and it is not obvious, even though I am pretty sure that polyphasic sleep will do its ravages faster than smoking. Cognitive tests would be first to show the change. Probably followed closely by the immune function and the glucose metabolism. However, a big part of the damage is the opportunity cost of polyphasic sleep. It is not only what it does to health, but also what one could have accomplished as a result of the intact mental capacity.
A GP cannot easily detect long-term effects of possible damage at the neural level, e.g. within the scope of the sleep control system. Nor can he or she see the impact of changes in the neural function on his or her patients' long-term growth and intellectual accomplishment. Things you do not learn today may change the entire course of your life. No one can estimate that cost. Even a substantial neural damage in Alzheimer's disease is not easily diagnosed at first, and it does not become obvious until the affected person enters the advanced stages of the disease when significant portions of the brain are gone! Human brain is great at compensating, and spotting damage is not easy.
Visiting your GP for a checkup is always a good idea. However, it is pretty useless as a way of preventing damage done by sleeping polyphasically. Polyphasic sleepers often report symptoms typical of sleep deprivation: thermoregulation problems, changes in appetite, immune deficiency, etc. It is hard to drive those to become serious threats in a short run. After all, even a few hours of "core sleep" quickly remedy most of these.
Someone suggested to me that "sleep deprivation is bad because it is a source of stress. But how bad it can be depends on how well one can handle stress". It is true that the susceptibility to stress in sleep deprivation is increased, but it is not true that stress management can be a solution to sleep deprivation. It is true that a good diet might improve the health of a smoker, but diet alone does not solve the problem of smoking. The only ultimate solution to smoking is no smoking. Similarly, the ultimate solution to sleep deprivation is sleep.
My own polyphasic sleep trial
Very often I am being asked how I can claim any authority on polyphasic sleep without ever trying it for myself. For starters, I do not claim to be a polyphasic sleep expert. As a humble biologist, I simply need to recall the ABC of chronobiology to figure out that polyphasic sleep is not feasible. You do not need to be a junkie to study drug addiction, even though a glass of vodka might be a recommended one-time treatment to an abstinent investigator of alcoholism. I understand the pain of the alarm clock because I used it sparingly during my university years. I understand the pain of jet lag and sleep deprivation from my early turbulent years of involvement in the SuperMemo business. However, I need a fresh brain for my work. Even one day of a hazy mind is a loss. I cannot possibly hope to struggle through a polyphasic routine in hope of proving that the elusive and ever remote "adaptation" is just an urban myth. If I was to take on my own sleep experiment, it would rather be a segmented sleep attempt (Wehr 1992). I can imagine it could do wonders to learning and creativity. However, few people in this world can afford a 10 hour waking day. It seems that only paid volunteers are ready to taste the blessings of excessive sleeping. Before a superficial reader concludes from Wehr's work that polyphasic sleep is possible, let me stress that his segmented sleep experiment spoke of chunks of very long sleep, not Uberman-like mini-naps.
Charting polyphasic sleep
Source of data
After publishing "Polyphasic sleep: Facts and Myths" (Wozniak 2005), a few dozen of young men wrote to me requesting assistance in entraining to polyphasic sleep schedule. Ethically, I could only proceed from an attempt to dissuade the young enthusiasts from proceeding with their experiment. Needless to say, these are not the types that are easily persuaded to veer off their course. As I wrote in Facts and Myths, these are "rebellious men ready to seek new ways for maximum productivity". No scientific argument can be persuasive enough in such circumstances. After all, all reasoning can easily be quashed with "science does not yet have all the answers". None of the young rebels succeeded in entraining polyphasic sleep, yet some were persistent enough to provide valuable SleepChart data that helped shed some light on the implausibility of the long-term use of the polyphasic sleep schedule.
Stampi yachting research
In data obtained by Stampi, we see the timing of semi-polyphasic sleep of a solo sailor in an actual yachting race. In this case, the Circadian graph reveals the forbidden sleep zone in the first part of the day, and a clear circadian preference for initiating sleep in the hours 15-24 of the waking day (blue line):
The red circadian curve is meaningless here due to the fact that sleep is artificially interrupted. In addition, artificial control of sleep is the reason why there is a role reversal between the sleep maintenance curve and the sleep initiation curve. In this case, it is the sleep initiation curve that best expresses the circadian sleep propensity.
A periodogram generated for this seemingly noisy sleep shows a typical biphasic pattern with peaks at 23.9 hours and 12.1 hours. 23.9 hour day and the associated phase advance are most likely caused by the impact of change in time zones when sailing eastward:
Polyphasic sleep attempt
In an attempt to entrain to a polyphasic sleep schedule, a male adept started his experiment with a schedule of 4 naps of 30 min., and a "core sleep" of 3 hours at 20:00 with an intent to reduce it to 30 min. in "due course". The entrainment ("adaptation") appeared elusive as the adept kept failing to fall asleep during some naps, while continuing to struggle with alertness in some of the allocated waking periods. The circadian graph shows the ultradian sleep initiation with a circadian preference for sleep in the period of the subjective night in hours 14-22 from the estimated beginning of the subjective day:
The core sleep could not be shortened as planned without a progression into more and more severe sleep deprivation. Instead, the core sleep increased in length slightly and moved to a later hour. Gradually, daytime naps started disappearing until the adept moved to a typical biphasic sleep of 5-6 h in the evening, with a 30-60 min. nap in the morning (and an occasional extra nap during the day if the core sleep resulted in heavy sleep deprivation). One year later the adept was nearly monophasic with only one rule leftover: "try to go to sleep before midnight". The effort is documented in this blog.
Uberman sleep logs
The picture shows SleepChart logs of the three most disciplined Uberman sleep adaptation attempts that I managed to collect from prospective polyphasic sleepers. The graph illustrates the efforts of Greg (A), Bryan (B) and Claudiu (C):
At 9 days, Greg's attempt was quashed by the clustering of "core" sleep in the early morning hours towards the end of the experiment (log A). This clustering was certainly caused by the mounting sleep deprivation adding to the peak of circadian sleep propensity in the periods of the subjective night.
At 22 days total, and 13 days without "core sleep", Bryan's attempt was the longest (log B)(full log is included in the next section). This attempt started showing signs of "strain" already on the first day with four extra naps in the first four days. Some oversleeping started showing consolidation in the period of the subjective night on Day 7. Finally, at midday, on Day 14, the subject fell into a long restorative 11-hour sleep bout. The attempt continued for some 8 more days with numerous extra naps, oversleeping, periods of grogginess alternating with elation. In the end, Bryan's detailed notes allowed of an interesting conclusion: the circadian cycle of sleep propensity was most likely running free in the background during the entire experiment showing a nearly perfect 25 hour cycle period. For a detailed analysis and explanation see: Free running circadian cycle in polyphasic sleep.
At nearly 5 full days, Claudiu's attempt was the longest "pure Uberman" before experiencing his first lapse into an extra nap (log C). It is equally notable for its never having missed a single nap beyond Day 1. It is important to note, however, that many nappers find it difficult to determine if they actually fell asleep during naps that come in forbidden zones. What they mark as a nap might have actually been a few short moments of microsleep.
Most bloggers who claim success with polyphasic sleep seem to have trimmed their standards of satisfactory alertness and creativity. When statements such as "my successful experiment" and "groggy" come together, you can be certain that "the experiment" does not effectively maximize their alertness and productivity. Sleep inertia should be foreign to a healthy sleeper.
There could be many interpretations of "successful" Uberman sleep claims that are pretty numerous in the blogosphere. None of these "successes", however, is likely to be explained by the disappearance of the natural circadian rhythmicity that makes polyphasic sleep so hard to bear. If the adept was indeed to become arrhythmic, this would spell a serious health and longevity risk. At best, this could imply a dysregulation and decoupling of sleep control centers (see: Sleep-wake flip-flop). At worst, this might involve a glial injury to the brain centers responsible for sleep control. Needless to say, such dysregulation or injury changes would be difficult to reverse and would result in serious problems with achieving refreshing sleep. That would be the antithesis of the goals of Uberman hopefuls.
Two-process sleep model vs. polyphasic sleep
Polyphasic sleep data collected from Greg (A), Bryan (B) and Claudiu (C) (see earlier) was processed with SuperMemo in an attempt to see how the timing of naps in an unpredictable circadian phase affects the sleep propensity:
SuperMemo implements a variant of the two-process model Borbely model that makes it possible to predict alertness and/or sleep propensity on the basis of the history of sleep and wakefulness. Users of SuperMemo 15 (or later) can inspect their own sleep propensity prediction data using Shift+click in the sleep log at any selected point in the timeline.
In the presented picture, the thick red line represents estimated alertness, and an inverse of sleep propensity. The circadian sleep propensity is marked in aqua blue. It is easy to see that the shape of the alertness curve depends on the circadian phase at which a nap occurs. The graphs were juxtaposed so that to align nap timing while having them occur at different circadian phases that produce different alertness estimates. The graphs show that the same nap timing may produce entirely different alertness profiles. This explains why the "energizing power" of polyphasic sleep is an easily propagated myth.
Even though the sleep model used in SleepChart applies to free running sleep, the symmetry of Uberman napping nullifies the need to correctly predict the circadian peaks and valleys. Wherever the acrophase peaks occur, they will largely intersect with the nap grid at random. In addition, if regular sleep data had been collected before the polyphasic sleep experiment, correct subjective nighttime acrophase estimations from that period would carry over across the first few days of the polyphasic experiment. After all, only consistent phase shifts can reposition the circadian sine wave phase. The same mechanism that makes polyphasic sleeping so hard to sustain can also be used to explain it with the model designed to serve a free running sleep condition.
What primarily emerges from the application of the two-component model to "Uberman sleep" data presented above is a typical "rollercoaster effect" of alternating alertness and grogginess. Unlike a typical sleeper who wakes up refreshed and goes to sleep tired, a polyphasic sleeper will experience moments of extreme euphoria (e.g. at 4 am in the graph B) and discouraging downers (e.g. at 3 pm in the graph C). The presented alertness estimates correlate well with the subjective "focus and motivation" assessments made by the sleepers themselves. In the graph C, where a nap at 11 pm produced a major surge in alertness, the nap at 3 am, just 4 hours later, delivered nearly nothing. This produces a typical rollercoaster of enthusiasm and self-doubt in a polyphasic sleeper. After short naps that occur at the minima of circadian sleep propensity, a polyphasic sleeper may reach heights that are not known to ordinary sleepers. Those surges of enthusiasm verging on euphoria are pretty unique due to the fact that an ordinary sleeper nearly never naps at circadian sleep propensity minima. Those moments can make a polyphasic experimenter update the blog with "never felt better - creativity at its maximum". At the same time, some naps can only make things worse. For example, the nap at 3 pm in the graph C taken on June 23, 2009 does not seem to produce any boost in alertness. It was then followed by an hour long "correction" that would not boost the alertness either. Moreover, the cresting circadian wave always produces the unpleasant feeling of grogginess due to a circadian sleep inertia. This is the type of inertia that is pretty familiar to shift-workers. That combination of sleep process variables is also responsible for the foggy head of the jet lag. This illustrates what Dr Stampi noticed in his experiments that it is not hard to stay awake on a polyphasic sleep schedule. The hardest part of a polyphasic regimen is the process of waking up from naps that occur at the circadian acrophase (Stampi 1992)
Free running circadian cycle in polyphasic sleep
Bryan's polyphasic attempt (mentioned earlier) brought the most interesting observation: the circadian cycle was most likely running in the background as if in zeitgeber-free conditions. In line with the chaotic impact of polyphasic sleep episodes on the sleep control system (see: Phase response curve in polyphasic sleep), the episodes largely cancel each other out and allow of a free-running circadian cycle run in the background. Moreover, return to the monophasic lifestyle can be nearly painless if the right phase for sleep time is chosen.
Bryan would keep his log in Excel with detailed annotations. Interestingly, he used coloring to denote periods of alertness or even euphoria, as well as periods of grogginess or sleepiness (yellow):
persistent sleepiness, fatigue, lack of focus & motivation
normal/neutral state, not overly sleepy or awake
heightened mental clarity, focus, motivation, enthusiasm
The columns correspond with successive days of the experiments and include preceding and succeeding monophasic sleep blocks. The rows correspond with half-hour periods. Sleep blocks are marked with their duration in minutes. In the graph, Bryan's Excel notes have been modified slightly to visualize the extent of the subjective night. Most importantly, his oversleep blocks were marked yellow instead of blue to differentiate them from an artificiality enforced polyphasic sleep, which tells us nothing about his actual sleep propensity. This way a visually distinct diagonal yellow band emerges where the presumable maximum circadian sleep propensity is marked without a distinction between the oversleep episodes and periods of grogginess. I demarcated that yellow band with blue and red bedtime and waking lines of putative boundaries of the subjective night in the same way as it is done in SleepChart. The blue line is the actual optimum time where Bryan should best go to sleep (instead of sleeping polyphasically). The angle of those lines, and the related phase-shift of the circadian cycle point to a nearly perfect 23-day turnaround, which roughly corresponds with a 25-hour body clock period. In other words, we can guess that the circadian cycle was running free in the background despite multiple chaotic and unpredictable inputs to the phase-shifting system. It is also remarkable to see how easily Bryan returned to his monophasic lifestyle by hitting the exact brackets of the subjective night in his free running circadian cycle.
Red and blue lines in the graph show a phase advance, while the rhythm almost certainly showed a phase delay. The reason for that failure is that the statistical method of SleepChart 1.0 uses sleep blocks as markers of sleep propensity. Naturally, in polyphasic sleep, those markers are falsified, and throw the algorithm into confusion. On the other hand, the newer approach used in SleepChart 2.0, based on the phase response curve (PRC), was able to roughly follow the circadian trough noticed in Bryan's Excel file. Here, the yellow circadian crest line is thrown into some confusion in the period from Feb 20 to 23. This is why the approximation does not recover in time to match the return to monophasic sleep.
Even though, at best, Bryan was able to sustain the pure Uberman schedule for only 3 days in a stretch, his one-month-long effort is still a remarkable demonstration of self-discipline. If you read Bryan's own notes on his cognitive function, you will probably agree that multiple periods of sleepiness, fatigue or grogginess disqualify polyphasic sleep as a lifestyle choice for people who use their brain for a living. Still Bryan's own words summarizing his experiment are pretty surprising. He does not seem to be bothered by "periods of sleepiness" or "difficulty waking up", which should never be part of a well-managed and hygenic sleep pattern:
My experiment demonstrated to me, unequivocally, that it is possible to maintain normal (subjective) function (mentally and physically) on a polyphasic sleep schedule, if you are willing to adapt to the rigid schedule of naps, and endure a period of sleepiness (circadian low) that lasts between 2-4 hours each day. In parallel to Stampi's findings, the only significant difficulty I experienced was waking up from naps as the experiment progressed. It became increasingly difficult to wake up; sometimes I would wake up and reset my alarm without any memory of doing so; or my girlfriend would have to shake me for a full minute until I awoke. Once awake, however, I usually felt great, as if I had slept a whole night—but without the sleep hangover (lethargy) from being in bed for 8-10 hours. It is tempting to focus on the difficulty of waking up, to make claims about what that does or does not indicate, but the normal, even euphoric, functioning during waking hours should not be ignored. Given this, I was happy to see that you address these matters in your paragraph titled, Polyphasic rollercoaster.
Probably nobody knows more about polyphasic sleep than Dr Claudio Stampi. He dedicated his life to understanding ultradian rhythms and the art of napping. His passion for the idea was born three decades ago when, as a medical student, he was also a passionate solo sailor. He studied sleep in dozens of individuals taking part in competitive sailing. He studied sleep patterns for NASA. He studied polyphasic sleep in laboratory conditions. He strapped his subjects with wrist-worn activity monitors and EEG electrodes. He is a worshipper of napping as nothing counteracts sleep deprivation and fatigue better than a nap. In his work, he looks for ways towards improving alertness and survival in life-threatening situations, esp. long-distance boat racing. Yet he is not recommending the polyphasic schedule for normally functioning creative individual who can afford a full night of healthy sleep. His alleged "recommendation" is just one of those myths circulating along with the polyphasic sleep meme. Using polysomnographic tools, Stampi looks for troughs and peaks in human alertness. His research tries to capitalize on understanding those ultradian rhythms and maximizing the effectiveness of napping, primarily by optimizing the timing of naps.
Stampi's methods are primarily targeted at minimizing sleep deprivation. He is a biphasic sleeper himself and through his chronobiology expertise can claim proudly "I am never tired". When speaking about Ellen MacArthur he puts his research in a nutshell:
What Ellen is doing is finding the best compromise between her need to sleep and her need to be awake all the time
Polyphasic vs. creative lifestyle
Unlike a solo sailor, a creative individual needs no compromise. It is the uncompromising maximum of alertness, attention, and creative powers that is sought. Stampi has shown that polyphasic sleep can improve cognitive performance in conditions of sleep deprivation as compared with monophasic sleep: Individuals sleeping for 30 minutes every four hours, for a daily total of only 3 hours of sleep, performed better and were more alert, compared to when they had 3 hours of uninterrupted sleep. In other words, under conditions of dramatic sleep reduction, it is more efficient to recharge the sleep "battery" more often. Many use this as the argument for the superiority of polyphasic sleep, while silently skirting around the fact that Stampi also notes that the performance on polyphasic schedule is still far less than that in free running sleep conditions.
Many proponents of polyphasic sleep will quote from their Bible: Claudio Stampi's book Why We Nap: Evolution, Chronobiology, and Functions of Polyphasic and Ultrashort Sleep written in 1992. Why We Nap is an excellent book, filled with peachy nuggets of information about sleep, napping, evolution, and more. I can wholeheartedly recommend the book as a great compilation of interesting texts from the most reputable experts in the field. The book also includes an anecdotal note on putative sleep habits of Leonardo da Vinci. It is possible that this anecdotal inclusion had an unintended side effect resulting in the Uberman Big Bang. With the advantage of two extra decades of sleep research (e.g. the genetic aspects of the circadian cycle), I disagree with some of Stampi's original hypotheses. Largely so does Stampi. This does not change the fact that his research can definitely be considered as pioneering work in the study of the extremes of chronobiology. For those who still believe that Stampi advocates polyphasic sleep as a lifestyle, an ancient quote from his book should clear things up:
the author would like to caution against misleading interpretations of these conclusions. What is being proposed here is not that polyphasic sleep is preferable to monophasic sleep, nor that everyone should now switch to a multiple napping behavior "panacea." It appears obvious that quasi-monophasic sleep — monophasic sleep plus occasional naps — is what comes most naturally to the majority of adult humans and a few other species. If somewhere in evolution such species have developed the ability to sustain wakefulness for relatively prolonged periods, most likely this ability occurred in response to some sort of important and advantageous adaptive pressure
Dr Stampi writes: "many experiments have provided direct evidence that adult humans have a surprising ability to adapt to different types — and different levels — of polyphasic sleep-wake behavior." This statement is general enough to be correct. For example, compression of sleep stages is a form of adaptation. This does not imply that an individual will be able to take multiple natural naps during a day. A consensus emerges in sleep research that, in healthy adult individuals, multiple Edisonian naps require a degree of sleep deprivation. Without deprivation, initiating sleep becomes pretty hard. "Multiple naps" should be understood as "more than one after consolidation", where "consolidation" is a process in which multiple naps spaced closely together are counted as one.
Cognitive tests in polyphasic sleep
It is important to note that Dr Stampi could identify only a modest decline in cognitive function during his polyphasic sleep experiments. This may stand in seeming contradiction with other research or with simple circadian measurements of memory performance, including those that are possible with SuperMemo. Including a circadian component in measurements yields significant cognitive differences in the course of a normal undeprived waking day. Simple memory tests, if averaged, might yield a seemingly reasonable cognitive performance assessment due to the roller-coaster effect. The tests Stampi chose to measure cognitive performance skirt around the essential question as to the primary long-term neurophysiological function of optimally timed REM-NREM interplay in sleep. In Stampi experiment with Francesco Jost, REM and NREM rarely occurred together. If the hypothesized memory storage optimization function is considered, it is impossible to verify the status of memory with short-term tests. This is due to the fact that, in theory, the network function of the brain taken as a black box should remain unchanged. The neglect of sleep structure would show only as a cumulative long-term inability of the brain to build up new skills and reasoning powers. Secondly, the creative potential of an optimized storage is also difficult to measure, and will definitely show a cumulative effect requiring a long-term study. Last but not least, lack of the circadian effect can only testify to an insufficient sensitivity and/or timing of the tests chosen. Even if the homeostatic component of alertness ensures that we can seemingly focus on simple mental tasks and perform them pretty well (e.g. memory tasks, driving, simple calculations, etc.), the circadian low will affect the ability to sustain a mental effort or undermine its creative aspect. Tests that could be sufficient for Dr Stampi's goals (e.g. maximizing alertness in a solo yachting race) cannot be used to make claims about the long-term impact of ultrashort sleep on cognitive performance.
In sleep science literature, there is a degree of confusion between the homeostatic and circadian components of sleep and their impact on cognition. Very often, researchers fail to differentiate between the two when investigating impact of environmental factors on sleep. We all know that coffee can help one survive a sleepy moment. It is important to ask though if its effects are homeostatic or circadian. Can coffee dispel sleep inertia? Can it help overcome circadian lows? It is not enough to say that coffee helps overcome sleepiness if its impact on the circadian sleepiness is negligible. Everyone who is familiar with the jet lag can testify that the foggy brain state does not evidently deprive one of one's basic mental skills, and yet it can entirely ruin one's productivity by affecting self control, creativity, motivation, and more. This is why globe-trotting politicians are a poor material for groundbreaking peace or trade deals, even if they believe they can function well on 3 hours of sleep or in a jetlagged condition. Dr Stampi's findings, highly applicable to emergency situations, should not be used to diminish the importance of well-timed natural sleep for the function of the brain, and the fact that artificial designer sleep schedules are very harmful.
Sleep deprivation is like alcohol intoxication
Sleep researchers love to compare sleep deprivation to intoxication: both disrupt one's self-assessment abilities. Like an alcoholic who always claims "I am not drunk. I am just inebriated", a sleep deprived person will often say "I am fine. I am crisp and alert", while his or her ability to perform mental tasks may be seriously impaired. The sleepier people are, the more overconfident they are about their ability to perform cognitive tasks. Driving when sleep deprived may be as dangerous as driving while intoxicated. This loss of self-assessment capacity may in part explain why so many polyphasic sleep bloggers tend to claim they have adapted to the grueling regimen. They tend to write about their success at the moment of lucidity and/or euphoria (see polyphasic rollercoaster). At the same time, they keep ignoring those brain dead moments as "temporary setbacks", transitory adaptation state, etc. In those hazy moments, a blogger may be unwilling to update the blog, magnifying the bias in the perception of his or her reporting. Natural adaptation to a polyphasic schedule is not possible, but those who boastfully claim it need not be branded as liars. Self-assessment handicap and a lowered bar of expectations should both be used as exculpatory circumstances. As mentioned earlier, it is even possible to flatten or desynchronize the circadian function bad enough to lessen the pain of waking in the period of subjective night. As this relief comes from malfunction, or perhaps even neural injury, it should serve no comfort to those who hope to adapt. With all the genetic cascades resting on the circadian cycle, such an outcome can only lead to a health disaster.
Sleep debt and napping
Power of a nap
The art of napping has the power to double creative productivity. Churchill was a famous biphasic sleeper. His naps let him squeeze two productive days into 24 hours. The explanation lays in the natural creativity cycle. However, those who try to emulate Churchill or Edison often fail to follow the facts of science and fall into a trap of sleep mythology. The most notorious blunder committed by young adepts of better sleep is the confusion between biphasic sleep and polyphasic sleep.
For a nap to express its full power, the following conditions must be met (in order of importance):
- it should take place at the center of the midday circadian nadir (see: Best nap timing). This corresponds with Mediterranean siesta
- it cannot be regulated with alarm clocks, caffeine, or other sleep "tricks". Coffee naps are a good idea for people in a hurry, not for those who care about brain productivity
- it should be the only nap of the day (i.e. it cannot be part of a polyphasic sleep schedule)
- it works best in free running sleep with no sleep deficit
- it works best in people with no physical or mental health issues
- it works best in habitual nappers who improved the quality of their naps from month to month by adjusting and perfecting little details in their surroundings. Beginners are often too anxious to fall asleep
There is a correlation between the duration of a nap and the duration of the night sleep. The relationship between the two is non-linear:
In the presented example, a negatively exponential function provides a good fit to data. However, in the most studied range corresponding with the nighttime sleep ranging from 4 to 8 hours, a nearly linear relationship can be observed where each hour of lost night sleep requires 20 min. of replacement nap time. This shows that napping has a powerful compensatory power.
One midday nap should be all that's needed to compensate for lost night sleep. As a result, it makes more sense to replace a number of naps with a single nap whose duration will depend on the amount of lost sleep:
NapDuration = (SleepRequired - SleepObtained) / 3
This formula will hold only for properly timed naps. Early naps will not provide full compensation. Late naps will last longer and will shorten sleep in the following night.
This formula should only have a theoretical value. You should never try to terminate a replacement nap. If it is properly timed, it should be allowed to run its natural course and it will then provide the best compensation for sleep lost in the night.
Sleep debt and napping
PureDoxyk is the nick of the "inventor" of the "Uberman sleep schedule". Even though she claims to have slept polyphasically for a longer while, a more detailed look at her reports indicates that she slept in a sort of messy multi-nap compensatory sleep system that gradually gravitated in the direction of a pretty natural biphasic sleep that she later termed "Everyman sleep schedule". Were it not for that gravitation and a tendency to take a "core sleep", I might even suspect that the inventor of the Uberman sleep cycle suffered from a rare mutation that causes circadian arrhythmicity. People with that disorder cannot sleep well in a long block over the night and take multiple naps during the day. Those naps add up to a pretty normal total sleep duration and produce a pretty unrefreshed mind that makes the disorder pretty hard to live with. It would be an ironically sad turn of events if a sick person suffering from bad sleep could have proposed a sleeping "system" that caused an epidemic of lifestyle experimentations by teenagers looking for better sleep only to find more sleep-time misery.
What strikes me in PureDoxyk writings is that she instantly rings credible and seems to have a very good sense of the link between sleep deprivation and napping. Let's have a peek at her claim that I will call PureDoxyk Law. Note the "six hour sleep" fragment that indicates that PureDoxyk is not suffering from a serious circadian arrhythmicity disorder as speculated above:
Six naps no sleep; 4 naps one-point-five hours sleep; 3 naps three hours sleep; 2 naps four-point-five hours sleep; one nap six hours sleep*.
Note (*): I removed two tiny mathematical kinks from the law which was originally formulated as: Six naps no sleep; 4-5 naps one-point-five hours sleep; 3 naps three hours sleep; 1-2 naps four-point-five hours sleep; one nap six hours sleep (source)
Obviously, this law would need to be parametrized to fit a general healthy population. In particular, most monophasic sleepers will find it hard to nap more than once per day unless all sleep episodes in question are terminated with an alarm clock, perpetuating the cycle of sleep deprivation.
We can instantly see a nearly perfect linear nature of the relationship between the duration of the night sleep and the number of naps taken.
NapNumber = 5.6 - 0.8*CoreSleep
PureDoxyk law in biphasic sleep
If we take the formula for the number of compensatory naps taken by PureDoxyk and apply it to biphasic sleep we instantly see that in a natural healthy biphasic sleep cycle with a single siesta, PureDoxyk law yields a night-time sleep of 5.75 hours.
This number is eerily similar to my own night-time average. Out of sheer curiosity I checked my average nighttime sleep for the years 2000-2017 and was pretty shocked to see it is was 5.69 hours. This might be just a coincidence, but the irony of that coincidence is staggering. I have been critical of polyphasic sleep mythology since 2002 or so, and it appears my sleep needs are almost identical as those of the only "natural" polyphasic sleeper in existence!?
Sleep and aging
While checking on my night sleep average, I also noticed that my night sleep kept getting shorter over decades. The graph is actually pretty scary. If the trend continues, I will soon enter night-time sleeplessness and die like rats in Rechtschaffen experiments.
Figure: Average length of night time sleep decreasing in the course of two decades (Wozniak 2000-2017)
It is true that with aging our sleep needs might diminish slightly, esp. if our brainwork slows down or health deteriorates. However, I am glad to know that with compensatory napping at 1:3 ratio, my value sleep total might have actually increased (
NightSleep + NapSleep*3). The optimistic interpretation might be that in free running sleep, with improvements in the art of napping, the demand for night sleep might drop. Perhaps Dr Kripke would be glad to see a case of improved sleep quality with less sleep. For more see: Biphasic life
Minimizing total sleep time
If Puredoxyk Law is true, the duration of naps will determine the breakeven point for the overall time gain in polyphasic sleep. Beyond the breakeven point in nap duration, adding extra naps will add to the total cost of sleep. Obviously, that breakeven point will coincide with the situation in which the total amount of sleep is constant (i.e. independent of the number of naps). If we take total sleep as:
TotalSleep = CoreSleep + NapNumber * NapDuration
NapNumber from PureDoxyk Law, differentiate for nap duration, and compare the result with zero, we will arrive at the breakeven point at NapDuration = 75 (min), which corresponds with the constant total sleep time of 7 hours. In other words, adding naps shorter than 75 min. would result in an overall time gain in polyphasic sleep.
A theoretical graph showing the minimization of the total sleep time along PureDoxyk Law. The proximal horizontal X axis shows the number of naps, the receding horizontal Y axis shows the nap duration, while the vertical Z axis shows the total sleep time in hours. The breakeven nap duration line is labeled "75 min". The graph shows that adding naps that are shorter than 75 min. allows of achieving a total gain in time, while adding naps longer than 75 min. will result in an increase in the total sleep time.
It would be interesting to analyze irregular sleep logs that comply with the above law as they could answer some questions on the winner in the tug of war for sleep efficiency between the regulatory powers of the free running sleep and the adaptive powers of the sleep compression induced by the use of an alarm clock in polyphasic sleep.
The net time gain in a short-nap regime obviously does not translate to a brain gain, and this should not be understood as a recommendation to seek minimum total sleep time. I posed the above problem only as an interesting mathematical relationship, which provides a neat formula for the total sleep debt that might be of use in modeling sleep in conditions where sleep is terminated prematurely (e.g. with an alarm clock). Neither SleepChart nor SuperMemo account for sleep debt as both have been designed for the ideal free running sleep condition. Obviously, any form of sleep debt is unwelcome as it implies unfulfilled neural function of sleep.
Personality characteristics of irregular sleepers
That PureDoxyk got sufficient experience in sleeping polyphasically to formulate the above law without any specific logging tools indicates that she needed a pretty vast array of napping permutations to see the bigger picture, which in this case seems highly plausible. PureDoxyk Law can be interpreted as a demonstration of how a healthy mono- or biphasic sleep can be stretched into a polyphasic sleep phase space with an increasing degree of sleep debt. PureDoxyk herself calls her new sleeping regime that includes a "core nap" the 3-hour Everyman schedule. This schedule sounds pretty sustainable if it is not too heavy on the use of the alarm clock. After all, a third of Americans can function reasonably ok despite committing the daily neural crime of using the snooze button for the average of 3 times. Needless to say, this Everyman schedule is a pretty wide departure from the original Uberman formulation that I found particularly troubling.
In the past, I have received a number of sleep logs with pretty irregular sleep patterns (including multiple naps). Those logs were accompanied by some anecdotal evidence that seems to indicate that those irregular patterns are strongly correlated with some personality characteristics. I can be widely speculative here and say that those are pretty neurotic and yet quite creative types (excluding cases that could be attributed to the use of prescription drugs). If that was to be the case, those sleep patterns might not be too good for longevity, but even free running sleep will fail to straighten them out. This indicates that there could be genetic factors involved here, and the "mutation hypothesis" is far more likely to explain a perpetual irregular pattern than a regular fresh-and-alert Uberman pattern. I would even avoid the use of the word "mutation" here as those "personality genes" must be pretty widespread in the population. How can PureDoxyk's case be interpreted, I have no idea, but it does not seem to be too extreme in its uniqueness, and, as such it can be, probabilistically speaking, deemed credible.
How geniuses sleep?
An Internet rumor has it that there were many geniuses who slept polyphasically. The implication is that if polyphasic sleep worked for the greatest minds in history, it should also work for a young ambitious student with a voracious appetite to conquer the world. Yet on a closer inspection, those polyphasic stories are very hard to confirm or very easy to instantly falsify. Somehow, the group does not include contemporary Nobel winners, presidents, or great athletes. In other words, you cannot just e-mail a celebrity and ask. All great polyphasic sleepers are dead. There are still a couple of individuals who boast in their blogs that they are polyphasic sleepers. Very often their sleep is just a stretch of the biphasic sleep definition or a combination of various sleep modes with a heavy dose of sleep deprivation. Some of those cases I cannot explain in any other way than by a vested interest or a bloated ego. As their "success" post-dates the "invention" of the Uberman sleep schedule, this might simply be a not-so-credible wish to be added to the list of the great Übermenschen. Even narcolepsy would not explain the alleged napping habits of some polyphasic adepts. At any rate, successful polyphasic sleep cases are not in any way verifiable. Naturally, absence of proof is no proof of absence, and this section is not intended to prove that polyphasic sleep is not possible. It is the biological argument that settles the case. Here, I only try to illustrate the myth-making powers of the Internet and human nature.
The list of polyphasic geniuses seems to be getting longer along with the snowballing myth of the benefits of a 22 hour waking day. The list includes da Vinci, Edison, Tesla, Churchill, Benjamin Franklin, Thomas Jefferson, and even Bruce Lee. I would not be surprised if Newton and Aristotle joined soon. Perhaps even Jesus might follow up later. I tried to find out if there is any record of the sleeping habits of the greatest geniuses in history. All I could find was rather a standard adherence to a normal monophasic or biphasic sleep, with an exception for numerous all-nighters at the time of creative high. Geniuses tend to instinctively stick to the natural creativity cycle.
The amateur "investigators" of the history of genius often get discombobulated by the fact that the healthiest sleep, biphasic sleep, technically speaking, can be classified as two-phasic. This is why a classic biphasic Churchill made the list of polyphasic sleepers.
With Buckminster Fuller, I came closest to finding a sort of quasi-polyphasic schedule. Buck's biographers who I managed to get in touch with confirmed that his sleeping habits were quite unusual and that he experimented a lot with various sleeping patterns. In particular, while traveling and lecturing extensively, he would enter what he called a "dog sleep". That sleep, however, had nothing to do with polyphasic sleep. It was a sort of improvised mix of free running sleep confounded by jet lag, meetings and deadlines. In other words, Bucky would catnap whenever he was tired and had an opportunity. However, if he could squeeze a sound 6 hours here and there, he would not miss the chance. This "dog sleep" did not fit any fixed alarm-clocked schedule. It was just a compromise between the circadian rhythm and Bucky's hectic lifestyle.
Leonardo da Vinci
Although even Stampi anecdotally refers to Leonardo da Vinci, Leonardo's polyphasic sleep is probably an urban myth. I could not locate any credible sources with any notes on his sleep habits, and yet da Vinci is nearly always mentioned whenever the art of napping comes into question. It seems quite strange that someone would come up with a crazy polyphasic schedule idea at the time of leisurely Renaissance life that was well-timed by the superiority of sunlight over candlelight. Allegedly, hinting at a monophasic mindset, he spoke of death: "As a well-spent day brings happy sleep, so a life well used brings happy death". Even more telling is Bandello's report on da Vinci's work over "The Last Supper". Leonardo would work continuously from dawn to dusk forgetting about food and drink. Stunned Bandello would have definitely reported the round-the-clock work of a polyphasic sleeper as even more amazing. It seems to me that using a poorly researched historic case from 500 years ago as a prop in favor of polyphasic sleep is rather a dated argumentum ad verecundiam.
I suspect the entire Leonardo myth might have originated from a 50-year-old story told by a psychic! Giancarlo Sbragia reports in his text on ultrashort sleep (1992):
I cannot recall exactly where or from whom I gathered information about Leonardo's sleep habits. [...] I had a friend who was a medium and capable of extrasensory perception. [...] It was probably from her that I learned about the peculiar Leonardo sleep-wake pattern, even though today, 30 years later, I am not completely sure. (Sbragia 1992)
Incidentally, da Vinci is also a name that crops up on many other suspect lists: the lists of great people suffering from attention deficit disorder, or the lists of great vegetarians. He is also a suspect fabricator of the Turin Shroud. The same memetic mechanism must be placing da Vinci, Jesus, Einstein, Edison, Jefferson, Franklin, and Hitler alongside each other in a number of myths over and over again. They keep popping up on trumped up lists of famous people affected by X, practicing Y or believing in Z.
Napoleon is not less frequently referred to in the context of napping or polyphasic sleep than da Vinci. And his case is rather easy to falsify through historical records. When compared with an artistic genius of Leonardo, it seems even more preposterous for a brilliant military commander to possibly retire for a nap during a prolonged battle or during his intense life peppered with plethora of engagements. He is indeed said to have slept little and frequently. He suffered from insomnia at times of great stress. He was also often interrupted by messengers that might perhaps increase his propensity to napping at daylight. Yet he was to be woken up only with bad news. The hard rule was that the good news could wait. His memoirs indicate that he did not mind dying young. Consequently, he would disregard his doctors on the matter of sleeping little and drinking buckets of strong coffee. As Napoleon's life was jam-packed with stress, his short sleep might have been a consequence of his lifestyle. Low sleep diet did not translate well to Napoleon's military skills. Some contemporaries attribute his errors at Waterloo to sleep deprivation. Yet, during slower days he would sleep for sound seven hours, waking up at 7 and often lazing until 8. Then he would yet add a nap in the afternoon. Records also indicate that at Saint Helena he was a normal sleeper, and when stress was replaced with boredom, he often slept late.
Jefferson seems easy to falsify as a polyphasic sleeper as well. In letters to Doctor Vine Utley (1819), Thomas Jefferson writes about his sleep habits. We can conclude that his sleep was not very regular, he would go to sleep at different times (often late into the night), he would always devote at least 30 min. to creative reading before sleep, he would fall asleep later if the reading was of particular interest, and he would regularly wake up at sunrise. In other words, expectedly, there are no traces of polyphasic sleeping in Jefferson's life.
As for Benjamin Franklin, we might conclude that he did not hold sleep in high esteem. This we can decide from the famous quotations such as "There will be sleeping enough in the grave" or "The sleeping fox catches no poultry". This attitude resembles the one of those who are ready to practise polyphasic sleeping today. It is also a frequent characteristic of high achievers from the times when we knew little of the biological function of sleep. Yet Franklin is even better known for saying: "Early to bed and early to rise makes a man healthy, wealthy, and wise". From this we might conclude that if he wanted to sleep less, his formula would be to get up early. Not to shred sleep into pieces. Moreover, for a high achiever with little regard for sleep, retiring for a nap might feel like a major sign of laziness or weakness. That stigma lasts until today in western culture, where napping is often considered a habit of lazybones. Last but not least, Franklin as an advocate of DST would say: "It is silly and wasteful that people should live much by candle-light and sleep by sunshine". If we look at his exemplary schedule preserved for future generations, we instantly notice that he instinctively observed the natural creativity cycle. He had two major work blocks: early in the morning and in the afternoon, separated by a time to slow down. For sleep, he reserved a full seven hour block. Polyphasic sleeper definitely he was not.
We know quite a lot about Winston Churchill's sleeping habits. As a wartime PM, his daily routine was watched closely by his assistants. Churchill could work his ministers to exhaustion by staying up late, but he would also routinely take a solid 1-2 hour nap in the afternoon. As such, Churchill was a classic biphasic sleeper. At his house at Chartwell, his routine was quite regular. He would wake at 8, spend the morning in bed reading papers, dictating letters, etc., take a long nap at tea time, and work till as late as 3 am. He averaged 5-6 hours of sleep per day. Those words are attributed to Churchill himself: "You must sleep sometime between lunch and dinner, and no halfway measures. Take off your clothes and get into bed. That's what I always do. Don't think you will be doing less work because you sleep during the day. That's a foolish notion held by people who have no imaginations. You will be able to accomplish more. You get two days in one -- well, at least one and a half". Churchill's well-drilled biphasic habits made him one of the most energetic wartime leaders. On a humorous note, F. D. Roosevelt's aides noted that after a Churchill's visit, the US president was so exhausted that he needed 10 hours of sleep for 3 days straight to recover.
Thomas Alva Edison
Thomas Alva Edison had a love-hate relationship with sleep. Sleep researchers blame him for robbing the modern population of 1-2 hours of sleep. Workaholics like to quote him on his contempt for sleep. Advocates of polyphasic sleep claim he was a polyphasic sleeper. Indeed, Edison's contempt for sleep is well documented. Yet it can only be attributed to his ignorance. Little was known about the biological role of sleep at his time. He believed wrongly that, as with food, humans will always sleep more than necessary given an opportunity. As a natural short sleeper, he believed that long sleep is a sign of laziness: "Most people overeat 100 percent, and oversleep 100 percent, because they like it. That extra 100 percent makes them unhealthy and inefficient. The person who sleeps eight or ten hours a night is never fully asleep and never fully awake - they have only different degrees of doze through the twenty-four hours". In a parallel flash of ignorance, Edison could not see much value in physical exercise. His winter home featured one of the first modern swimming pools, yet Edison never used it. He just did not share the modern view in which exercise and sleep are considered a good investment in mental and physical health. His co-workers noted that Edison actually slept far more than he would like to admit. Clearly, he would carry sleeping little as a badge of honor. He catnapped a lot, and his nap cots have been preserved to this day in Edison museums. By no means could I though find any credible evidence that Edison's napping complied to any regiment other than "nap when sleepy", which usually turns out to match a biphasic pattern, or at least comply with PureDoxyk Law. The most reliable information I could find about Edison's sleep was his own diary kept only for a short time while approaching the age of forty. From this diary we can learn a lot about his sleeping habits. He seemed rather obsessed with getting a good night sleep as his day would often start with notes on the quality of sleep. Like most of us, the better he slept, the happier he seemed. That's quite the opposite of what polyphasic proponents claim. Instead of maximizing waking hours, Edison would rather maximize the hours in which he could use his well refreshed mind. And that's exactly what seems most rational from the point of view of physiology of sleep, mental hygiene, and productivity.
After a short stint under Edison's umbrella, Nikola Tesla became a bitter rival of his former mentor. We have all heard of the "war of the currents", but Edison and Tesla clashed in another battlefield. They tried to outbid each other in sleeping little. Tesla noted that Edison slept much more than he would want others to believe. That injects a dose of boastful personality into Tesla and Edison's own reports on how much they actually slept. I bet the same mechanism makes today's bloggers often boast of polyphasic adaptation. Tesla, who could indeed work throughout the night, would often crash for the entire day of sleep after his exploits. He exhibited classic signs of manic creativity, which might have been interrupted by short recuperative naps or long recovery sleep. Otherwise, Tesla was nothing more than a short sleeper. He was too busy with his pursuits to ever think of anything resembling a strict polyphasic schedule. That would be a strait jacket on his flamboyant personality.
All in all, the whole list of polyphasic geniuses seems to be lacking any credible evidence. As such, it is probably a child of collective wishful thinking committed by those who would love to add waking hours to their day.
Sustainability of polyphasic sleep
The main problems with the polyphasic sleep result from the fact that it is:
- hard to fall asleep during the sleep's forbidden zones,
- hard to wake up from deep subjective night sleep, and
- the body clock trainability has its limits that make it impossible to circumvent problems (1) and (2).
Clock and Hourglass model of polyphasic sleep
If you decide to sleep polyphasically you will have to use an alarm clock. Otherwise you will not wake up in the night. Once you use the alarm clock, you will be sleep deprived. That will make your hourglass conveniently drained of energy. Empty hourglass will make napping easier indeed. But it is the hourglass that determines your mental powers. With the hourglass empty, you will be nothing more than an empty-headed zombie. To generate naps at equal intervals, you would have to kill the 24-h circadian component of sleepiness. You would have to kill your body clock, and prevent the release of the sleepy potion. That is not possible. The sleepy potion will be released every 24 hours and make you sleepy; however hard you fight it. The shortest natural night sleep rarely goes beneath 3 hours. Many biphasic sleepers can do well on 4 hours. Yet most adolescents may need 7 or 8 hours of night sleep to function optimally. In healthy sleep, daytime naps are either impossible or very short. If you track your sleep with SleepChart Freeware, you can see it all on your own. You will see how naps tend to cluster at night time (which may be midday for you). That's exactly what polyphasic guru Dr Stampi observed with solo sailors. Remember, for the picture to be true, you should avoid alarm clock, which naturally is not possible in polyphasic sleep. Yet even on a forced schedule you will see regular patterns of naps being longer and more frequent at nighttime (each time you relax your discipline, oversleep, etc.). The daytime naps will be shorter, esp. at subjective evening hours (which may be midnight for you).
The limits of the body clock training
I hear it again and again that all biological reasoning is of no consequence because the body can always adapt to training and pressure, and that science has not yet studied successful polyphasic sleepers. Here is a reply based on the clock hourglass model:
- body clock is controlled by genes, and we do not know pharmacological factors that could significantly affect body clock period. Polyphasic sleep would require shortening the body clock period six-fold! Another possibility is the complete removal of the body clock so that the hourglass of mental energy could govern sleep cycles
- body clock phase can be shifted with light, activity, melatonin and other factors, but the length of the period in which sleepy potion is released is hard to control. Drugs can reduce the impact of sleepy potion, but this should be avoided, as this affects the sleep stage cycles. In terms of the Disk and RAM metaphor, not all your PC data may get written to the hard disk and get defragmented
- the speed at which the hourglass of energy is emptied can be affected by drugs (e.g. caffeine); however, faster hourglass would produce more sleep (instead of less), while slower hourglass would make multiple naps even less possible
- polyphasic sleep in laboratory conditions is possible if the alarm clock is used to interrupt natural sleep. Entrained free-running polyphasic sleep is not possible in healthy individuals
- science has not studied successful adapted polyphasic sleepers with natural polyphasic rhythms because they do not exist (although there are many claimants to the title). Dr Stampi's experiments do not qualify as they always involve an alarm clock
Healthy body clock runs a 24 hour cycle. This cycle will make you sleepy during the subjective night (which can be midday too). This is why you won't be able to wake up from your nap in your subjective night without an alarm clock. Alarm clocks are unhealthy. They prevent sleep from fulfilling its function. The choice is yours: either (1) sleep polyphasically or (2) sleep naturally and let your brain develop its full intellectual potential. If you are still not convinced, please read this message from the inventor of Uberman sleep
Caffeine in polyphasic sleep
Polyphasic sleepers believe that avoiding caffeine may ease the adaptation. Because of a relatively slow elimination of caffeine and its impact on adenosine receptors cancelling homeostatic sleepiness, ingesting caffeine later than 5-7 hours before a nap is supposed to make taking a nap more difficult (except for cases when the ingestion takes place directly before a nap).
It is true then that avoiding caffeine shall make taking multiple naps somewhat easier. Yet it won't remedy the problem of grogginess when waking up in the period of subjective night. The problem in sleeping polyphasically is the asymmetry of the circadian cycle (which is only marginally affected by caffeine), and a slow build up of homeostatic sleepiness. Even complete abstention from caffeine will not generate sufficient homeostatic sleepiness to ensure napping at all desired times. Reversely, taking powerful adenosine agonists would more likely result in sleep patterns that would rather resemble narcolepsy, not a desired Uberman sleep. That would go precisely against the goal of polyphasic adepts, which is to sleep less. Polyphasic sleep pattern is inherently unstable, and changing levels of caffeine will have no bearing on this fact whatsoever.
As for the normal healthy sleep (which polyphasic sleep is not), abstention from caffeine is not necessary, but all caffeine drinks should be optimally taken only within the first two hours after waking.
Polyphasic sleep mutants
Some polyphasic sleep adepts wondered if singular blog reports of polyphasic success could be due to some mutation that made those individual more likely to succeed. This is theoretically possible, but highly unlikely. To make the "mutant theory" workable, we would need a mutation that would produce sleep without a circadian component. Such a mutation is actually known and results in a serious disability coming from a perpetual sleep deprivation. People affected by this mutation will never be normal sleepers (like polyphasic sleep adepts). Another mutation might allow of homeostatic generation of states that resemble circadian lows that periodically occur in the brains of all vertebrates. It is as hard as to imagine a mutation that would allow one of defecating in 25g portions. Or a mutation allowing of an asynchronous voluntary peristalsis. Or a mutation that would replace a blinking reflex with two separate independent regulatory blinking mechanisms for both eyes. Or a perpetual syncopated heart rhythm with alternating 3:6:3:9:3:6 interval ratios. Or a separate contraction of atria, or separate repolarization of ventricles, etc. Or a menstrual cycle that can be entrained to shift-work with bleeding every 9 days. The closest disorder that can match the hypothesis that polyphasic sleep might be enabled by a mutation is narcolepsy, in which individuals node off many times during the day indeed. However, this is a homeostatic disorder that does not flatten the circadian function. As such, narcoleptics sleep more than healthy people, not less. In 1996, researchers were able to make Siberian hamsters arrhythmic by playing with their exposure to light (Ruby et al. 1996). However, their body clock was still running its cycle and responding to light-induced phase shifts, while only the locomotor activity rhythm became decoupled. We know that arrhythmicity in humans will cause a serious disability due to sleep's inability to fulfill its function without its circadian component. Moreover, it is hard to compare the genetics of humans with an animal that lives in cold climates and spends periods of prolonged darkness deep underground in its burrows. The chances of similar genetic "adaptation" to polyphasic sleep are probably comparable to the odds of humans getting their hair white for winter.
Last but not least, how would I tell a polyphasic mutant? He or she would have most likely been polyphasic from birth. Even though PureDoxyk has never been truly Uberman-like polyphasic, her sleep patterns have always been somewhat irregularly polyphasic. This is what makes her case credible. In genetic terms, biphasic sleep is pretty distant from the well-entrained ultradian polyphasic sleep. Even babies are hardly ultradian (see: Baby sleep). In other words, when an otherwise healthy human being suddenly claims a polyphasic adaptation, I can only be seriously skeptical.
Polyphasic sleep blogs
As I could not run my own polyphasic experiments or encourage others to sleep polyphasically, I gathered a lot of insight into the Uberman concept by reading polyphasic blogs on the web. There are dozens of these and they provide a pretty entertaining reading. In addition to a perpetual struggle with sleepiness or grogginess, those blogs also ooze lack of understanding of the principles of healthy sleep and gross disregard for the importance of sleep in general. Here is a representative quote: "If someone lives for 75 years, they will be unconscious for 25 of them. That's my entire life until now completely wiped away, unused. Family, school, work, writing, all of you, none of it happened. That is the cost of sleeping eight hours per day. So I cut my sleep to two hours, trying to milk my short life for all it's worth". For someone who cannot appreciate the role of sleep, this sentence might not sound as outrageous as it should. However, as most of us appreciate the value of work, this sounds to me more or less as follows: "If someone lives for 75 years, they will be at work for 25 of them. That's most of my life until now completely wiped away, unused. Family, school, sleep, writing, all of you, none of it I had time for. That is the cost of working eight hours per day"
One of the theories of the biological basis of humor says that it is generated by the sense of superiority over other individuals. Allegedly, those who are able to detect the ignorance of fellow human beings, reinforce their findings through the sense of joy and well-being. Thus seeing others doing stupid things is fun (as long as, hopefully, nobody gets hurt on the way). Supposedly, the evolutionary mechanism of poking fun at the silly ones helped humans preserve wisdom through generations long before written records were available. In that context, if you understand the sleep control mechanisms that imply the impossibility of entrainment to polyphasic schedule, you may find studying the blogs of polyphasic sleepers extremely funny. Actually, hilarious. With clues and red flags all over the place, the bloggers keep hitting the brick wall. Luckily, those individuals usually see the light after a few weeks of pain. We should hope that nobody gets hurt in the process, e.g. as a result of driving in a sleep deprived state. All blogs seem to roughly evolve through similar stages. They begin with a youthful euphoria about the potential of Uberman sleep to change one's life for better. There is a cultish aura around the whole concept. It parallels the work ethic and self-imposed or super-imposed sleep deprivation of Aum, Branch Davidians, OTS, or Peoples Temple. This monastic appeal is accentuated by the fact that the ambitious adopters often run various forms of diets as part of their "reform". There are lots of hopes associated with the "polyphasic experiment". Those usually revolve around being able to do more, and experiencing "increased energy". The hopes are magnified by the fact that many volunteers find it difficult to get refreshing sleep in the first place. Then the struggle begins, peppered with hopeful references to "temporary adaptation phase". It all begins with grogginess, problems with waking up, and oversleeping. Tiredness mounts and the word count analysis shows that "tired" is one of the most often used words in those blogs (along "I" and "nap"). Yet the happy "polynapper" is usually able to survive the initial phase through sheer enthusiasm magnified by the availability of extra time and tripled energy to execute a major change in his life. Then the negative aspects of the experiment start showing up. Those include insurmountable sleepiness, sleeping through an elaborate system of alarms, problems with thermoregulation, negative somatic symptoms, self-blame due to repeated oversleeping, etc. Repeatedly, oversleeping occurs in the subjective night, while problems with napping occur in the subjective day. Yet "polynappers" are slow at noticing that regularity. They are happy they get the extra waking time, and yet, instead of spending it productively, they desperately look for anything to kill time to "just survive the fog". They waste precious time on futile attempts to fall asleep at a wrong time. When things do not work their way, they start experimenting with various variants of the sleep schedule. Those include: more naps, fewer naps, longer naps, shorter naps, "pseudo-naps", rigid schedule or "flexi-naps", etc. As these are usually fruitless, the concept of "core sleep" or "recovery sleep" comes into consideration. Some experimenters decide to "listen to the body". With "core sleep" and some attentiveness to one's own body rhythms, experimenters drift towards variants of biphasic sleep, and may gradually approach a reasonable sleeping schedule. Yet without understanding the basics of the two component model of sleep regulation, it is very difficult to figure out one's optimum sleep timing. The difficulty is compounded by two factors:
- conviction that polyphasic sleep model will work, and
- loss of synchrony in circadian rhythms.
As for the latter, well-entrained free running sleep is relatively easy to understand. However, once strong phase-shifting stimuli are introduced into the system, esp. if applied asynchronously or, worse, with irregular patterns, the whole sleep control system becomes chaotic and is essentially unpredictable. In other words, even a seasoned chronobiologist might find it difficult to interpret the correlation between the timing of sleep blocks and alertness. If the unlucky experimenter does not see the biphasic light, he begins theorizing on the causes of his inability to stick to the schedule. These might be bad foods, bad hormones, lack of self-discipline, skipped naps, extra naps, troubles at work, friends, excess sleep, too much REM, too little REM, too little "Stage 4 REM" (sic!), etc. The theorists speak as if one could easily guess the "level of histamine", or the duration of "Stage 3 sleep" in a nap (no blood test nor EEG needed). Falling asleep within 3-5 min. should be a breeze in a healthy free-running individual, yet polyphasic sleepers constantly battle with not being able to fall asleep fast enough while in circadian high. Equally hard, they battle with waking up from the nap while in circadian low. No wonder then that oversleeping continues, and the battle with drowsiness takes its toll. In the end, the blogger usually postpones the experiment to "better times" (after Christmas, after vacation, after the crazy period, etc.). Sometimes the blog just ends abruptly without a conclusion. Rarely does the "polynapper" admit defeat, or concludes on the infeasibility of polyphasic sleep. Few, disingenuously, claim the successful adaptation to the sleeping schedule and go on to blogging on other subjects.
Those young men tend to be hungry for life, hungry for experience, hungry for accomplishment, unable to adapt to 10 pm - 5 am sleeping schedule, rebellious and ready to seek new ways towards maximum productivity. These are mostly noble characteristics. But in a mix with ignorance, they can lead to bad health, poor decision making, poor mental performance, and social frictions. These personality types are also at a higher risk of dying young. Polyphasic sleep may also have its contribution: "I have just driven polyphasically all the way from Canada". There is only one major benefit of polyphasic sleep: polyphasic bloggers contribute to our understanding of sleep. No researcher could ethically subject that many individuals to the mental torture of polyphasic schedule. In this article: Polyphasic sleep: Myths and Facts : Comic Relief, I compiled a list of funniest quotes from polyphasic blogs. Those illustrate the phases of the experiment with the special focus on oversleeping and alertness. Naturally, the list is very selective and out of context. Bloggers often claim they feel great, the method works, and they plan to continue indefinitely. Yet interwoven with the enthusiasm are red flags that amazingly keep passing unnoticed. A couple of blogs even scream great success. I won't quote or link to these as I found them quite disingenuous, or carrying a hidden agenda. These would dilute the truth and hype up a potentially hazardous lifestyle.
Myth: We can adapt to polyphasic sleep. Looking at the life of sailors, many people believe they can adopt polyphasic sleep and save many hours per day. In polyphasic sleep, you take only 4-5 short naps during the day totaling less than 4 hours. There are many "systems" differing in the arrangement of naps. There are also many young people ready to suffer the pains to see it work. Although a vast majority will drop out, a small circle of the most stubborn ones who survive a few months will perpetuate the myth with a detriment to public health.
Fact: Humans are biphasic and the attempts to modify the inbuilt circadian rhythm will result in loss of health, time, and mental capacity. A simple rule is: when sleepy, go to sleep; while asleep, continue uninterrupted.
- False! most animals are polyphasic and so must be humans
- False! adaptation period is hard but it ends at some point
- False! polyphasic sleep saves you time
- False! polyphasic naps are REM-only
- False! you are more alert if you sleep polyphasically
- False! you are more productive if you sleep polyphasically
- False! you lose weight on the polyphasic sleep schedule
- False! polyphasic sleep reduces ghrelin (the appetite hormone)
- False! polyphasic sleep boosts testosterone levels
- False! polyphasic sleep is healthy
- False! long naps are bad for you
- False! many naps are better than one nap even if you are not sleep deprived
- False! Claudio Stampi recommends polyphasic sleep to everyone
- False! polyphasic sleep maximizes the amount of REM an individual gets
- False! many geniuses of history slept polyphasically. Not a single one has been documented actually
To read some hilarious extract from polyphasic sleep blogs, see: Polyphasic sleep: Myths and Facts : Excerpts from polyphasic sleep blogs
- Czeisler C.A., Duffy J.F., Shanahan T.L., Brown E.N., Mitchell J.F., Rimmer D.W., Ronda J.M., Silva E.J., Allan J.S., Emens J.S., Dijk D.-J., and Kronauer R.E., "Stability, Precision, and Near-24-Hour Period of the Human Circadian Pacemaker," Science / Volume 284 / Issue 5423 (June 25, 1999): 2177 - 2181, doi: 10.1126/science.284.5423.2177
- Khalsa S.B.S., Jewett M.E., Cajochen C., and Czeisler C.A., A phase response curve to single bright light pulses in human subjects," The Journal of Physiology / Volume 549 / Issue 3 (June 15, 2003): 945-952, doi: 10.1113/jphysiol.2003.040477
- Ruby N.F., Saran A., Kang T., Franken P., and Heller H.C., "Siberian hamsters free run or become arrhythmic after a phase delay of the photocycle," American Journal of Physiology - Regulatory, Integrative and Comparative Physiology / Volume 271 / Issue 4 (October 1996): 881-890
- Thaler J.P., Yi C.-X., Schur E.A., Guyenet S.J., Hwang B.H., Dietrich M.O., Zhao X., Sarruf D.A., Izgur V., Maravilla K.R., Nguyen H.T., Fischer J.D., Matsen M.E., Wisse B.E., Morton G.J., Horvath T.L., Baskin D.G., Tschöp M.H., and Schwartz M.W., "Obesity is associated with hypothalamic injury in rodents and humans," The Journal of Clinical Investigation / Volume 122 / Issue 1 (January 3, 2012): 153–162, doi:10.1172/JCI59660
- Swaab D.F., Hofman M.A., and Honnebier M.B.O.M., Development of vasopressin neurons in the human suprachiasmatic nucleus in relation to birth," Brain research. Developmental brain research / Volume 52 / Issues 1-2 (March 1, 1990): 289-293, doi: 10.1016/0165-3806(90)90247-V
- Swaab D.F., Hofman M.A., Mirmiran M., Someren E.J.W. van, and Zhou J.N., "The human suprachiasmatic nucleus (SCN) in a periodic environment," Proceedings of the fifth Sapporo Symposium of Biological Rhythm (1994): 323-337
- Mirmiran M. and Ronald L. Ariagno, "Influence of light in the NICU on the development of circadian sleep component rhythms in preterm infants," Seminars in Perinatology / Volume 24 / Issue 4 (August 2000): 247-257
- Frank M.G., Issa N.P., and Stryker M.P., "Sleep Enhances Plasticity in the Developing Visual Cortex," Neuron / Volume 30 / Issue 1 (April 2001): 275-287
- Wehr T.A., "In short photoperiods, human sleep is biphasic," Journal of Sleep Research / Volume 1 / Issue 2 (June 1992): 103-107, doi: 10.1111/j.1365-2869.1992.tb00019.x
- Wozniak P.A., "Polyphasic Sleep: Facts and Myths" (2005)
- Stampi C. "Why We Nap: Evolution, Chronobiology and Functions of Polyphasic and Ultrashort Sleep." Boston: Birkhäuser, 1992.
- Zimmermann T., "Miles to go before I sleep," Outside Magazine (April 2005)
- Pryor M., MacArthur is caught not napping," The Times (January 20, 2005)
- Sbragia G., "Leonardo da Vinci and Ultrashort Sleep: Personal Experience of an Eclectic Artist." In "Why we Nap: Evolution Chronobiology and Functions of Polyphasic and Ultrashort Sleep," edited by C. A. Stampi (Boston: Birkhäuser, 1992), 180–185