Dual Core 1


Segmented sleep with naps
Default Dual Core 1

Dual Core 1 (DC1) is a schedule that evolves from Segmented sleep. It now contains three sleep blocks per day. Dual Core 1 is similar to E2, the equivalent schedule in the Everyman line with a similar total sleep. It is the first Dual Core prototype with new characteristics.

  • Reduction of some sleep from both or either cores
  • Addition of one daytime nap to compensate for the reduced amount of REM in the second core.
  • Polyphasic sleepers will now officially be able to learn to nap, as Segmented sleep does not have any naps.

DC1 is a very fair polyphasic schedule to attempt, given a decent amount of sleep, ~5.3-6.3h. It is one of the most beginner-friendly schedules. 


  1. Mechanism
  2. Adaptation
  3. Alternate Variants
    1. Less Common Core Durations
    2. Slightly Shortened Core Durations
    3. 30-minute Nap
    4. Long Morning Wake Gap
    5. Siesta-hybrid
    6. DC1-extended
    7. Non-reducing DC1
  4. Lifestyle Considerations


Dual Core 1’s mechanisms largely carry on from the original Segmented sleep. What applies to Segmented sleep is also present in DC1, with some changes. 

  • Each core sleep is around each respective sleep peak to further consolidate the overall sleep structure.
  • The first core may remain around the same or slightly shorter compared to that of Segmented sleep. This serves to preserve the amount of SWS.
  • The second core reduces in length so that the nap can facilitate REM sleep.

Core duration

Are the stock core lengths on DC1 and DC2 valid

However, there have been some changes in Dual Core 1’s scheduling proposals over the years. The most detailed compilation can be viewed in the attached PDF above. 

  • The standard variant should have a core sleep of 3h20m and 1h40m respectively.
  • The cycle length does not follow the common 90m rules mostly because of the effects of sleep peaks. This may lengthen the cycles of the dominant sleep stage in the peak. For example, a longer REM cycle around REM peak and a longer SWS cycle around SWS peak.

However, according to EEG readings of some community members, sometimes cycle length might remain the same or shorter; thus, there is more light sleep at the end of the cores. DC1’s original design was intended to have a total of at least 5h for both core sleeps.

This would be a reasonable upgrade from the sleep total of Segmented; at the same time, it is not overly taxing to adapt when a daytime nap is part of the schedule.

The Daytime Nap

  • The nap also bridges the long daytime wake gap which has increased because both cores have become shorter.
  • It is also in the circadian nadir around noon and early afternoon, which can give a familiar sense of daytime napping on E1 and Siesta. Alertness dips often occur around these hours, so Dual Core 1’s nap takes advantage of the natural energy dips to facilitate napping.
  • The nap does not always guarantee a high percentage of REM sleep. For some individuals, it only contains NREM2, or very small amount of REM; this is especially if the nap is somewhat late in the afternoon (after ~3 PM). Despite all that, the nap can sustain alertness for a long time until the first core (~7-8h); it is generally easier to stay awake in the day than during the night (~4-5h between 2 cores).

Dual Core 1 is often comparable to E2, because both of them are the first schedules in their respective schedule series (Dual Core & Everyman). They have a similar amount of total sleep and the same number of sleep blocks (3) per day. The only difference is that E2’s first nap is now a core in DC1, and that DC1’s first core should start earlier than E2 core.


Cold Turkey

This method mostly benefits naturally Segmented sleepers. They are accustomed to waking up at night or even doing Segmented sleep without their own awareness. Non-natural Segmented sleepers can also jump into Dual Core 1 cold turkey if there is not enough time to pull off a gradual adaptation.

However, the adaptation process is potentially much more strenuous, except the extended variants.

  • Since ~3h20m-3h30m core duration does not cover all SWS from the beginning (it usually takes 3 uninterrupted cycles, or at least ~4.5h core to do so), repartitioning of SWS and REM sleep into each core sleep is a requirement. Assuming an average amount of SWS requirement (~90-120m), the repartitioning process may be more or less intense.
  • High SWS requirements (at least ~130m) will likely require the extension of the first core (~4.5h instead) to cover all the SWS needs. Regardless of the disadvantage, several cold turkey adaptations to Dual Core 1 and its extended versions have reported success.

Gradual Adaptation

Gradual transition from Segmented

This adaptation method is likely slower than cold turkey; however, the transition may be less stressful from an adapted Segmented. However, there is no guaranteed success for Dual Core 1. Moreover, this method actually has seen lower success rate than the cold turkey method. This is largely due to the amount of time it would take to achieve good results on 2 successive adaptations.

However, sleepers who have fully adjusted to Segmented for a long time also have the advantage. The transition to DC1 at this point puts them on equal grounds with natural Segmented sleepers who are about to start a DC1 adaptation.

Alternate Variants

Currently, there have been a few DC1 variants that have been successful, although success rate is still “Your Mileage May Vary”. These alternate variants serve different purposes of different polyphasic adapters and have a varying success rate.

Less Common Core Durations

3.5-1.5 Core Combination

Original DC1 variant from Polyphasic Society

In this variant, both core sleeps still give a total of 5h, however, there is a slight difference from the current version. This variant was the first one proposed by Polyphasic Society.

  • The first core sleep is as long as the equivalent first core on Segmented sleep; this is based on the idea that the extra 30m sleep starting from the 3h mark gives some more REM sleep. However, this most definitely does not apply to every individual.
  • This core length is also applicable in E3 a lot of times.

However, Dual Core 1’s sleep peaks possibly give a different effect on cycle lengths. A 3.5h core in SWS peak may not yield the same result as the same core out of SWS peak.

This variant would be a strong step after adapting to Segmented with the first core being 3.5h, because there has been some entrainment with the 3.5h core. This variant has little success throughout the years, however. It is reliant on a gradual adaptation from Segmented, which lengthens the adaptation time it takes to adapt.

2.5-2.5 Core Combination

Both 2.5h cores

2.5h core is often very uncommon and difficult; for an average person, it induces mid-cycle (SWS/REM) wakes right at the start of adaptation. This in return increases oversleeping chance, especially in the first core.

Waking up from SWS has mostly been extremely challenging; on the other hand, waking up from REM is usually more manageable. However, both types of awakening can be just as disgusting during Stage 3.

  • This variant, however, would suit individuals with lower SWS needs and higher REM needs.
  • Some may also prefer a longer morning sleep to be more productive at early morning hours, especially if they are used to the night hours between cores.

Success rate up to date remains low; attempting a 2.5h core from the get-go is discouraged except in the case of experienced sleepers or those with sufficient understanding of their sleep architecture.

3-2.5 Core Combination

Somewhat longer core durations

This variant has seen at least 1 success over time, relying on the buffer extra sleep that lines up with the 90m multiple rule (to ease scheduling). The second core is longer to account for a higher REM need. The higher total sleep also increases the chance for flexing either cores to greater effects. However, it still remains largely unpopular to date.

Attempting this variant is not bad in itself; however, the 2.5h second core is expected to be uncomfortable during stage 3.

Slightly shortened core durations

Both cores total only 4.5h

There have been a couple attempts at this variant, however, success rate remains humble. The primary reason is the relatively low total sleep that almost looks like Triphasic sleep. The repartitioning of sleep stages will be a lot more intense than on the standard version. There are benefits, however.

  • More extra wake time than the standard variant
  • Requiring only 3 sleeps per day, with long wake gap between each sleep for various activities.

Beginners should not attempt this variant. In addition, it would be better for individuals with lower sleep requirements. It is also unknown how flexible this version would be after the adaptation phase; there are no records of its flexibility.

30-minute Nap

2.5-1.5h core combo
Both 2h cores

These variants originated from Triphasic sleep, whose total sleep is also 4.5h.

  • There is a longer sleep around SWS peak to further support SWS.
  •  The daytime core of Triphasic becomes a 30m nap.

Over time, both of them become DC1-modified rather than Triphasic-modified because there are 2 cores and 1 nap. Each of these variants with odd-cycle length has only reported 1 adaptation success.

The rare adaptations make sense because of the sleep lengths and require a lot more efforts to make them work. Though mostly not a good idea, the first variant (2.5-1.5) may be preferable to the second variant. A short-term adaptation is also possible. It can give a lot of extra wake hours as burst time to complete a lot of urgent tasks.

While no less difficult than the likes of Triphasic, these variants’ advantage is the shorter daytime nap. It is more convenient than the nap on Triphasic. If an adaptation is possible, the long-term prospect is also more promising than Triphasic.

The nap may be somewhat flexible after adaptation; unfortunately, neither successful attempters have shown how flexible these variants could be.

Long Morning Wake Gap

8h morning wake gap

Polyphasic Society originally posited this idea.

  • The heavy concentration of both cores at night resembles E1 or some sort of Biphasic schedule.
  • The wake gap between 2 cores decreases to 4h, while there is an 8h wake period between the second core and the nap.
  • The promised utility from this setup is that one can work straight from morning to afternoon hours. The noon break will not require any naps.

However, this has been very difficult and has essentially zero successful adaptation. Individuals with lower sleep requirement can take advantage of this variant, because they usually can stay awake longer with a more distant sleep distribution, than an average person would.

This is a common ground in scheduling with E2 as well, with the morning gap between both naps usually no longer than ~6h. This would limit excessive tiredness during the whole wake gap. The afternoon wake gap on DC1 and E2 (from the last nap of the day to the core) is usually tolerable even if they appear to be longer than the recommended length. Since it seems easier to stay awake during the day, up to 9h wake is viable for the afternoon gap.


The second core is like a siesta

It is uncertain what the advantages of this scheduling would have compared to the traditional setup. However, some individuals do claim that a short nap around sunrise hours would give more chance for vivid dream recall than a core sleep.

This is probably because of a higher percentage of REM sleep in a nap than in a core. Furthermore, the period of REM that ends before awakening is likely shorter on a nap than on a core.

Only one person has reportedly succeeded at adapting to this variant. The daytime core looks like that on Siesta, but it is questionable how it can be managed long-term, while a daytime nap is a lot more convenient to schedule.

Attempting this DC1-siesta hybrid is not advisable; the vast majority will be unlikely to adapt to this variant. 


Extension of the first core
Extension of the second core

Both of these variants over the years have reported a lot of success (although more for the 4.5-1.5 core distribution). They are very beginner-friendly and offer a reasonable amount of sleep reduction.

This would be approximately ~90m of sleep cut for an 8h monophasic sleeper. Those with a higher monophasic baseline (~9h) should also pick either variant. The choice between either variants comes down to REM and SWS requirements.

  • A higher REM requirement would favor the 3-3 core combination
  • A person with high SWS needs or exercise a lot for muscle growth can pick the 4.5-1.5 variant.
  • Both variants also have an advantage that the regular DC1 oftentimes does not. They can have a somewhat late first core sleep, which start around ~11 PM rather than 9-10 PM on the default version.
  • Both variants can have a long morning wake gap, up to ~8h until the nap because of a higher total sleep. Wakefulness sustaining is expected to be a lot easier than on a regular DC1 variant. This could allow one to stay awake through work and have a nap after work (~4-5 PM).
  • Both Dual Core 1-extended variations have great flexibility potential after adaptation. One can choose to proceed to DC2, or simply learn to adapt to DUCAMAYL with flexible sleep times.

Non-reducing DC1

Non-reducing DC1

The non-reducing version is only a very niche option.

  • It is for people who do not want to reduce their total sleep time because of personal reasons. Such reasons include the inability to follow a strict schedule, and not wanting to risk a period of impaired performance. 
  • Because DC1 builds on the Segmented sleep habits, naturally Segmented individuals can learn to add a nap around the hours they are drowsy. This would be an easy way to sleep DC1. 
  • Since there is no sleep reduction, it is possible to somewhat flex each sleep block with small increments during adaptation, rather than having to stick to strict sleep times everyday.
  • Despite this, non-reducing DC1’s true adaptation success is very rare. It mostly relies on the naturally Segmented tendency and the noon circadian nadir to take the nap.
  • Many may find non-reducing DC1 redundant; non-reducing Segmented already provides all the necessary sleep in the cores, and does not require taking any daytime naps.

However, certain scenarios may prove that a non-reducing DC1 is a fine option.

  • One can start to learn to have effective daytime naps to further transition to other reducing schedules. This is because Segmented sleep does not teach napping skills. Even so, it may still be difficult to fall asleep in the nap.
  • The daytime nap can help offset tiredness from work hours or if it is convenient to schedule a nap. 

Lifestyle Considerations

Similar to Segmented sleep, Dual Core 1 offers a variety of scheduling options in its arsenal. A lot of variants have become successful, although the bulk of the success is from the extended versions. Either way, DC1 demonstrates that one can:

  • Enjoy the night gap between the cores.
  • Keep up the Segmented habit.
  • Further cement the schedule with a nap for more rejuvenation.

Thanks to the sleep peaks and the circadian nadir around noon, DC1 is a well-rounded schedule.

The second core sleep is also great for a lot of REM sleep and can sustain alertness well into the afternoon. This can set the foundation for very efficient morning productivity. The extended version also spares more room for evening social time.

 However, like a typical Dual Core schedule, the first core sleep often starts at earlier hours than Everyman sleep to make use of the SWS peak; an Everyman schedule (e.g, E2, E3-extended) still has more vantage points in terms of evening social time.


Looking for potential research paper(s) on Dual Core 1? Check them out here. 

Wake Gap between DC1 Cores

Template of learning activities on DC1
  • Because of the characteristically different features of both core sleeps, it can be beneficial to study before the first core. Then, revise the learned materials during the night gap.
  • SWS, which is prevalent in the first core, is responsible for storage of declarative/explicit memory, e.g, recall of explicit factual information. A history, or a biology test, X happened on date Y. A in the body does which thing B.
  • REM is responsible for storage of procedural memory, i.e. remembering how to do certain things by following a procedure. Examples include how to walk, how to ride a bike, etc. In addition, REM (and NREM2) is also responsible for emotionally related memory consolidation, spatial memory consolidation. For example, which is the right route to a friend’s house.
  • If one is trying to remember procedures by repetition, the nap on Dual Core 1 can fulfill such purpose.
  • In case of chunks of information, they won’t benefit from the nap much. Rather, they would have to wait until the core sleep. Hence, it is best to study such materials before the core. Note that this does not only apply to DC1; other schedules with Dual Core features can also benefit from the experiment.
  • The sole nap’s function on DC1 also applies to the nap(s) any other schedules that are within the adaptability range and have proven to be stable long term.

Other Notes

  • Dual Core 1, however, is generally harder than its counterpart E2 because of the lower success rate (barring extended versions).
  • Regular DC1 is also borderline with inflexibility after adaptation. So far there are not many adapted DC1 sleepers that can flex the core sleeps by a lot. It would require lower sleep requirements or experienced sleepers to be able to manage a flexible DC1. While it is possible to achieve this, either cores may have to remain stationary. The cores may also not be any more flexible than 1h range (earlier/later than the originally scheduled time).
  • The nap on DC1 may be flexible, but it is uncertain how much.

Regardless, more data is necessary to determine how flexible DC1 can be compared to E2, whose second nap is highly flexible in a lot of adapted people.

Daily Life Suitability Outlook

Having only 1 daytime nap, DC1 is suitable for a lot of regular jobs that allow 1 nap during lunch break. Thus, its long-term potential is also very shining. This is an advantage over any schedules with a daytime core (e.g, Siesta, Triphasic) which is more difficult to schedule. However, while the extended variants are more resilient, the default variant is less likely so.

  • Any nighttime activities that force the first core into late night hours deserve strong attention. This can cause a shift in the entire schedule.
  • DC1 poses an overall more difficult adaptation than Segmented. Its less total sleep means the necessity to consider various factors that could affect the adaptation. These include, but not limited to: current level of exercise, health status, long-term sustenance and mental health.
  • The longer wake period between the cores may also not be suitable for everyone. Staying awake for many hours at night everyday can be boring and eventually overwhelming.

All in all, Dual Core 1 remains a solid schedule to attempt; it is one of the most balanced schedules with moderate difficulty. Additionally, there is the extra time, benefits of the night gap, the maneuvering of both sleep peaks and a unique experience from both core sleeps.

One core is very deep, potentially near a blackout yet peaceful and calm; the other one is often explosive with very colorful dreams. All these elements promise a blistering adaptation experience.

Main author: GeneralNguyen

Page last updated: 8 April 2021equi