DC1

DC1

Dual Core 1
chart link Legend   Sleep   Dark period   Flexible sleep window
Total sleep	5 hours 20 minutes
Proposed by	Polyphasic Society
Difficulty	Moderate
Specification	2 core sleeps, 1 nap

DC1 is a schedule which logically follows Segmented sleep, shortening its core (usually the second one) and adding a nap to compensate for the lost REM.

Possible variants

Extended sleep cycles

This variant is considered standard. It usually has 3h20m first core and 1h40m second core, theoretically making sleep cycles a bit longer (close to 100m). In fact, according to EEG readings of some community members, sometimes cycle length might be unchanged and shorter, so there is more LNREM inserted in the end of cores. The other possible standard variant is 3.5h + 1.5h, it might be a bit more difficult, but is also quite popular.

Standard sleep cycles

This variant has standard cores' length, 3h + 1.5h. It is rarely used and has a lower success rate since cores contain less light sleep/REM. It is considered more difficult than the standard one, and usually fits people with lower natural monophasic sleep baseline, about 6-7 hours or less.

Equal core length

Both cores are of the same length, 2.5h + 2.5h. This variant is viable, but rare. It is also considered more difficult than the standard one, since requires sleep cycle compression.

Swapped cores

In this variant the first core is swapped with the second one. The difficulty is also higher, because of the possible SWS wakes and the need for SWS splitting, which is easier for either experienced polyphasic sleepers or those with lower SWS sleep requirements.

Extended

The easiest and the most popular one, which has several variants. Usually 3h + 3h or 4.5h + 1.5h core variants are used, but other ones are also possible (e.g. 1.5h + 4.5h or 3.5h + 3.5h). It usually has 4 cycles instead of 3 (5 or more is also possible, but almost never is used). This variant fits adolescents or those with higher sleep requirements.

Shortened

This variant has only 2 sleep cycles, for example 1.5h + 1.5h or 2h + 2h. Is much harder and recommended only for those with lower sleep needs, 6h mono or less. It allows for much less LNREM/REM.

References

Polyphasic Sleep Schedules Scheduling overview Biphasic E1 Extended Siesta Segmented BiphasicX Everyman E2 Extended E3 Extended E4 Extended E5 Sevamayl Trimaxion Dual core DC1 Extended DC2 Extended DC3 DC4 Bimaxion Tri core Triphasic TC1 TC2 Nap only Uberman Dymaxion Tesla Spamayl Experimental QC0 Ducamayl Camayl Hypothetical Non-polyphasic Monophasic Random