Is Polyphasic Sleep Natural? A Two-tiered Adaptation Success System


Is polyphasic sleep natural? This is a very interesting question that both skeptics and aspiring polyphasic sleepers seek answers to. Because each individual’s perception of a natural sleep pattern may vary, this post will attempt to homogenize that concept. Ever since polyphasic sleep first made its name on the internet, though in the form of extreme nap-only configuration, many mainstream sleep scientists have taken a lot of jabs at this lifestyle. 

There are several matters that we need to make clear. As such, the focal attention of this post will cover the following topics:

  • The truest definition of a natural sleep pattern.
  • Two tiers of a successful polyphasic adaptation. 
  • Assessments of potential natural polyphasic schedules in humans


  1. Definition of a Natural Sleep Pattern
    1. Monophasic Sleep
    2. Is Polyphasic Sleep Natural in Humans? 
  2. Successful Polyphasic Adaptation – A Two-tiered Adaptation System
    1. Tier 1 – Stage 5
    2. Tier 2 – Stage 6
  3. Assessment of Natural Polyphasic Schedules in Humans
    1. General Rules
    2. Exceptions
  4. Recap

The Natural Sleep Pattern


A sleep pattern is considered “natural” if two criteria are met:

  • No intervention from alarm clocks
  • Feeling rested and fully functional throughout the day. 
Polyphasic Sleep Alarm Clock
Natural Sleep Does Not Need Alarm Clocks

While this appears to be common knowledge, many people, especially new polyphasic sleepers, are not aware of the second criterion. This is because performance metrics are usually hidden and conveys a more nuanced picture. For instance, a person may sleep and naturally wake up after ~5 or 6 hours asleep a couple days. They may also feel rested and perform well during those couple day(s).

Nevertheless, some days later they find out that they sleep longer, most typically during weekends or just the following day(s). Therefore, their natural sleep duration does NOT translate to 5-6 hours. In fact, new polyphasic sleepers, or people who do not know much about sleep can mistake themselves for short sleepers. 

With all that said, it is also necessary to consider factors such as sleep onset and duration of time actually asleep. Usually though, these factors have certain fluctuating variances and sleep quality is not set in stone everyday. The natural sleep duration as a whole, though, should not vary as much. So far, natural sleep patterns in humans seem to mostly point to monophasic sleep. 

Is Polyphasic Sleep Natural in Humans?

The concept of a natural polyphasic schedule remains the same as that of monophasic sleep. However, polyphasic sleep is different because there is more than one sleep phase each day and that includes nap(s). As a result, a natural polyphasic sleeper would have to wake up from their naps(s) and core(s) without using alarm clocks; additionally, there should be no performance deficit daily. 

To thoroughly answer this question, there are several factors at play. The factors will be the highlight of the Assessment section of this post. 

The complete lack of long-term studies on polyphasic sleep does not help the matter, either. As of currently, it is of ethical concern to conduct polyphasic sleep experiments that initiate sleep deprivation symptoms for several weeks. That is, until either it becomes clear that participants cannot adapt to pre-designed schedules, or that it takes too long for the body to finally clear the last hurdle and become comfortable with the new sleep pattern. Either way, mainstream sleep scientists and researchers are not fond of any of these scenarios. 

As a result, there are no official research conclusions on if all types of polyphasic sleep can be a natural fit for humans, and under which conditions. But, not all hope is lost. 

Successful Polyphasic Adaptations – The Two-tiered System

This polyphasic sleep adaptation model elaborates on further entrainment of human’s chosen polyphasic sleep schedule long-term. As such, the models only rely on anecdotes of successful long-term and short-term polyphasic sleepers. GeneralNguyen proposed this concept in 2020 with growing evidence of long-term records of adapted polyphasic sleepers. 

Tier 1 – Short-term Success – STAGE 5

For those unfamiliar with adaptation stages, refer to this post.  


Following the 4 stages, stage 5 marks a successful polyphasic adaptation. However, sleepers only truly enter this stage if they have sustained the adapted state for preferably at least 2 weeks (there are exceptions for this, see the Assessment section).

  • During this period of time, they are comfortable with not only their sleep-wake schedule, but also daily performance. This includes desired levels of physical exertion and cognitive functioning on various tasks. 
  • It is also possible to wake up naturally some time before a nap or a core ends. However, this only happens sporadically, and sleepers still need alarm clocks. 

Other Questions

Now, there are several possible concerns and questions regarding this stage. 

  • Can a sleeper drift back to the previous adaptation stages? Totally. A fledgling adapted state certainly will not hold itself together well enough yet. Therefore, abrupt, extreme changes in sleep times, skipping sleep randomly, increasing exercise intensity to steep levels or sickness can reverse adaptation. Though, this depends on the total amount of sleep on the adapted schedule. 
  • When does stage 5 “end”? There is no definitive answer as everyone is different. Expect at least several more weeks, or even months for the schedule to be more stable. This applies to reducing schedules, and even non-reducing schedules with smaller core(s) and added naps. But at this point, it is possible to recover the sleep schedule from events that force sleep extension, skipping sleep or lowering sleep quality some nights. 
  • Without external circumstances, is Stage 5 permanent with sufficient sleep hygiene and a healthy diet? No. There is always a likelihood of destabilization. This means that the adapted schedule may only be sustainable for a short period of time. Oftentimes, this is a result of adapting to a radical schedule with a very low total sleep. Alternatively, any schedules that do not fully provide enough vital sleep stages each day may over time slide out of control. Only a strong sleep tracker like Zeo can showcase the proper data. 

Overall, while on the rarer side, there have been personal records of polyphasic sleepers being in stage 5 for some time before failing to further carry on their sleep schedule. For short-term polyphasic goals, reaching stage 5 is already a success. 

However, stage 5 is not the end of everything. 

Tier 2 – Long-term Success – STAGE 6

The persistence and perseverance of certain long-term polyphasic sleepers gave the initiative for stage 6. Apparently, by this point, every aspect of a successful adaptation is done to much greater effects than that in stage 5. This category includes long-term practice of only one polyphasic schedule at a time, for an extended period of time. The current criterion is typically at least 1 year, or close to that benchmark. Note that this duration varies across individuals and polyphasic schedules. 

Staying in stage 5 for longer sets a strong foundation for stage 6. Currently, stage 6 is the final form of a polyphasic sleep adaptation. Upon reaching this stage, people become masters of their own polyphasic sleep schedules. By sustaining their polyphasic schedules for long periods of time, these sleepers gain new abilities

The journey to the final adaptation stage


Some characteristics of stage 6 are as follows:

  • Wake up from all types of sleep (cores and naps) without using any alarm clocks. Or at worst, no more than just one soft alarm in the morning for safety measure. 
  • External events, such as occasional party nights, emergency calls, work and other commitments only briefly derail the polyphasic schedule. As such, it only takes just no more than a couple of days for a stage 6 sleeper to fully recover their schedule and return to top form. 
  • Spend much less, if not negligible, time before each nap/core to cool down and prepare for sleep. All the while, these sleepers can still fall asleep fast (no more than a couple minutes). 
  • Enhance napping skills at flexible hours. Specifically, the veterans can change nap times comfortably depending on day or circumstances. The end result is still the same with high-end quality naps. 
  • Manage a flexible core sleep to a strong degree. While core sleeps on reducing schedules are often harder to move around than naps, their flexibility issues are minor for stage 6 sleepers. 

Other Questions

Similar to Stage 5, it is necessary to unveil possibly common queries about stage 6, judging its potent descriptions. 

  • Why is polyphasic sleep adaptation so difficult, as it takes this long to get here? Well, first off, any changes in lifestyle requires some form of adaptation, whether mild or not. Do remember that you likely have been sleeping monophasically for so many years. It won’t take just a few days to reach stage 6. If anything, the process will be (much) longer than you think. It’s a complete “overhaul” of a sleep regime, and it will not come easy. 
  • Is it possible to not change sleep times at all and forfeit all alarms eventually? That is also possible, just that it is usually unrealistic to do so long-term. Life commitments, other changes in schedules, plans, etc. are more than enough to foster sleep flexibility. In the long-term scheme, every sleeper will have to adapt to changes in sleep times; if they do not want to revert back to monophasic sleep, that is. 
  • Why are long-term polyphasic sleepers so rare? There are a lot of reasons to call it quits. For example, boredom with extra time, changes in lifestyle (which is no doubt the most common reason) that do not allow naps, or only short-term productivity goals. Successful polyphasic sleepers may also want to experiment with other schedules. As a result, it may be challenging to sustain one polyphasic schedule for long. 

Special Note

Are there fluctuations in sleep duration of a core/nap after alarms are not in use anymore? 

Yes! This is a result to be expected. It also seems to make sense to reflect the idea that personal sleep needs change everyday; although not by a huge margin with consistent sleep.

E3 can be natural sleep
How E3-extended may look like in Stage 6

Once the body has a strong hold on the schedule’s mechanics long enough, it will simulate the sleep-wake cycles accordingly. To illustrate, stage 6 sleepers can have a ~15-17m nap (or slightly longer than 20m sometimes) rather than the pre-scheduled 20m in the initial adaptation stage, while still on the same sleep schedule throughout. The core sleep can also lengthen or shorten a bit compared to the original length on a day to day basis. It is also possible to sleep “a bit” more than the original length some days, by a small margin, as in the napchart above. 

As a result, the concept of oversleepingoften seems moot in stage 6, except if sleep duration of a core or a nap suddenly increases greatly for no specific reason. For instance, a desired 3h core sleep becomes 5h, or a 20m nap becomes a 2h core. 


If stage 6 is present, it will give a solid answer to the question, “Is polyphasic sleep natural?” after all the wait. However, there are still quite a bit more determinants that entangle the process. Regardless, staying on just one polyphasic schedule for a very long time is a good scan for potential future health consequences. 

Assessment of Natural Polyphasic Schedules in Humans

This section will now dissect the different factors that can help polyphasic sleepers achieve Stage 6. However, keep in mind that your mileage may vary, as usual. Interindividual factors can generate unexpected outcomes, and vice versa.

General Rules for Natural Polyphasic Sleep

There are certain rules of thumb that the community data support:

Total Sleep

  • The higher the total sleep of a polyphasic schedule, the easier it is.
  • Usually, these very extended/non-reducing schedules (e.g, Biphasic-X) may somewhat resemble personal monophasic baseline (assuming 8h average). As a result, adapting to these sleep patterns will not trigger as many sleep deprivation symptoms that force the body to cope and adapt more harshly. 
  • So far, extended polyphasic variants score a much higher adaptation success rate (including stage 6 potential) than reduced equivalents.
  • As an example, E3-extended (5.5h total sleep) is much more successful than regular E3 (4-4.5h total sleep). The reasoning is simple – the body will require more time to adjust and make effort to “live” under a more reduced total sleep. 

Sleep Structure

The more closely a polyphasic schedule resembles monophasic sleep, the easier the adaptation.

Polyphasic Schedules

Regular Versions

Extended Versions

Overall Resemblance with Monophasic Sleep



Very Strong

All-around Strong


Somewhat Weak/ Medium



Dual Core

Slightly stronger than Everyman/ Medium


Medium/Medium high

Tri Core


Medium low

Somewhat weak (Triphasic-extended)

Flexible (-AMAYL), excluding SPAMAYL

Medium/Medium high

Medium/Somewhat strong

Usually medium/medium high


Very Weak


Overall Very Weak

Table. Polyphasic schedules similarity with monophasic sleep

    • Resemblance with monophasic sleep describes how each polyphasic schedule group looks, in comparison with monophasic sleep. Nap-only schedules have a very weak resemblance with monophasic sleep because they only have short naps around the clock
    • Variants such as E2-extended, E1-extended have a decently long core sleep at night, with a minimum of 6 and 7-7.5h respectively. In fact, this will be easier for the body to “remember” the former monophasic habits to transition into a “slightly” new polyphasic regime.
    • Simpler schedules such as Biphasic can enable a faster Stage 6. Non-reduced variants may even be natural for a few people from the start, bypassing Stage 5 immediately. 
    • In the table above, regular versions refer to the original, or default schedule on this website. Meanwhile, extended versions usually have at least 90 minutes of extra sleep in a core. 
    • Extended variants have more sleep that usually concentrates at night. Therefore, they can look quite like monophasic sleep. 
    • Everyman, Dual Core & Tri Core sleep all have at least one core sleep at night. Therefore, they all have some similarity with monophasic sleep. 
    • The table assumes regular sleep at nighttime hours, regular sleep requirements and a normal monophasic pattern. However, individuals with a broken monophasic pattern (multiple awakenings at night) will find Segmented/Dual Core types more natural.

Exceptions in Natural Sleep

With all that said, human potential is not limited to extended polyphasic sleep. There are much more unknowns that can determine the most natural sleep pattern in different individuals. This section only presents some of the established exceptions. 

Living Environment

Environment is also a factor that dictates sleep habits. 

  • Individuals from “Siesta-alike” cultures may already feel natural with a Siesta schedule. Examples include a core sleep of ~6h at night and a daytime sleep around early afternoon of 1-1.5 hours. This head start means that they have already been polyphasic for a long time, even without knowing it. 
  • More extreme living conditions can also create more exotic sleep patterns.
    1. The Piraha tribes, for instance, almost practice a nap-only schedule. They often have short naps throughout the day, and sleep no longer than 2 hours at a time.
    2. Likewise, many other tribes around the world are familiar with a Segmented-alike sleep pattern. They often wake up at night before going back to sleep, mostly to watch for predatory threats. See Sleep Patterns of Tribal People


  • It is a common fact that older people naturally, or involuntarily practice polyphasic sleep. This is, however, most likely attributed to their inability to sleep in one chunk for too long. Their sleep architecture has deteriorated, with light sleep being the majority and a remarkable reduction in REM and SWS stages. 
  • There are many possible polyphasic patterns in the elderly. They can take almost any form, but most notably segmented features. Awakening at night becomes more and more apparent, coupled with possible daytime naps. 

Medical Conditions

Though this area has largely been unclear and polyphasic sleep has largely been a topic that doctors evade, there are hidden potentials. However, a lot more research is mandatory to understand the mechanics of these conditions. Although, for the most part, these cases can get away with some levels of sleep reduction. 

  • Insomniac people can benefit from a slightly reduced total sleep compared to their monophasic baseline. So far, community results are diverse. Mostly though, natural sleep patterns predominantly exhibit in the form of a reduced Biphasic schedule. For example, E1 (6h core). Other variations include E2 (4.5-5h core), DC1-extended and some other. 
  • Depressed individuals and nightmare sufferers can enjoy daytime napping and segmented core sleep(s) at night. However, this has huge individual variances. 

Recap on Natural Polyphasic Sleep

  • Maintaining all adapted signs for some time after stage 4 opens the gateway to stage 5. Short-term polyphasic sleepers should embrace stage 5, because they more often than not do not have enough time to get to stage 6. 
  • It usually takes a very long time to reach stage 6. Expect no less than several months, or even 1+ year. Remember that personal mileages vary. Exceptions also do exist, such as napping culture, sleep history, living environment. 
  • Long-term polyphasic sleep is an accurate testament to how a different sleep regime from monophasic sleep can support human health and functions. It is a stern test to check for long-term sleep deprivation! Thus, we recommend polyphasic sleepers to stay on one schedule for as long as possible, after they start to enter stage 5
  • Stage 6 adaptation does not favor radically reduced polyphasic schedules. This applies to the vast majority of the human population. 
  • Even “reasonable-looking” schedules (e.g, DC1-extended, 6.3h total sleep) also do NOT guarantee a stage 6 for everyone. Keep in mind personal sleep requirements, lifestyle and other factors that can arise. 
  • Overall, mostly schedules with 2-3 sleep sessions per day, with a “reasonable” amount of sleep reduction or no reduction, can be natural in humans. They are easier to sustain and schedule around daily timetable. 
  • Lastly, polyphasic sleep can be natural in humans. However, it takes time and effort to experiment and find the best personal option based on the ground rules (total sleep, sleep structure, the amount of sleep reduction). 

Main author: GeneralNguyen

Page last updated: 22 October 2021