4-Stages Adaptation Model
This is the most popular and up-to-date model of polyphasic adaptation at present, which was developed by the polyphasic community.
Most popular polyphasic schedules are based on natural human sleep patterns . It is, first of all, biphasic schedules, which were widespread both before modern time and nowadays; Everyman, which uses the mechanism of power naps; Dual Core, which is based on the Segmented sleep patterns, popular in the pre-industrial society, as well as schedules with even more cores, which are based on a similar mechanisms to Segmented sleep. Monophasic sleep became popular relatively recently, after the industrial revolution .
Newer sleep schedules require an adaptation, which includes the repartitioning of vital sleep stages and teaching the brain to use another type of sleep. By the community observations, the process is usually similar for different individuals, which allows us to construct a stage-like model. The model contains 4 stages, which gradually transit one into another. The whole process takes roughly 4-8 weeks on average, though in some cases it might be much longer.
Staying awake is easy during this stage, hence sleep deprivation has not been accumulated to a large degree. Falling asleep is usually difficult for naps and easy for cores, assuming the person is not an insomniac and the scheduled core does not start earlier than the usual sleeping time. Repartitioning has not started yet, so the sleep quality is the same as in monophasic sleep, presumably with ~90-minute, uncompressed cycles. This stage is also beneficial for adjusting to new sleep habits.
The duration of Stage 1 is shorter for schedules with a low total sleep time or for individuals with pre-existing sleep debt. This does not shorten the whole adaptation process, but rather increases the duration of stage 3 and 4. Insomniacs might want to skip this stage of adaptation since it is much easier to fall asleep in the later stages, but generally this is not recommended. The benefit of falling asleep faster does not compensate the higher risk of oversleeping and the extended period of experiencing intense sleep deprivation symptoms.
This stage is mostly similar to the first one and can be distinguished from it by the sleep deprivation symptoms, which become more apparent, albeit not intense yet. Random tiredness dips start to occur more often throughout the day. Falling asleep usually becomes a bit easier, as sleep pressure keeps increasing. Similarly to Stage 1, this stage is shorter on the difficult schedules.
By Stage 3, sleep debt accumulates enough to cause intense sleep deprivation symptoms, which often leads to oversleeps or noticeable difficulty of staying awake. The intensity of this stage depends on the schedule though, and might be very mild for non-reducing schedules or insanely hard for the ones with an extreme sleep reduction. Stages repartitioning starts by this stage, so the sleep structure might be messy temporarily. It's much easier to fall asleep and much more difficult to wake up, wakes often are accompanied by a strong sleep inertia.
This stage is longer for the schedules with a low total sleep time or for the attempts with pre-existing sleep deprivation. Sometimes Stage 3 starts after only a few days passed considering these condition. Therefore it's recommended to go through a recovery process to reduce sleep debt before attempting a new schedule.
After sleep is efficiently repartitioned and mostly stabilized, sleeper enters the last stage of adaptation. This one usually closely resembles the first two stages, as the sleep deprivation symptoms finally become less intense after Stage 3. This stage should not be confused with the adapted state, since some microsleeps or even oversleeps are still highly possible without the necessary caution. The main reason is sleep debt, which still isn't fully recovered, often REM debt and a bit more rarely SWS debt. This stage is the last step for sleep stabilization and recovery, and adaptation is reached after the sleeper met the criteria, listed in the next section.
Some schedules might not be adaptable for a specific sleeper, this usually leads to never reaching adapted state after being stuck in a loop of Stage 3/4. Albeit Stage 4 sometimes is just much longer than average, usually either because of a high sleep debt or because of excessive flexing.
The polyphasic community has established some signs of adaptation, which help to distinguish adapted state from being on other stages. Adaptation usually is reached after gradually going through the above mentioned stages and staying on schedule for at least 4-8 weeks. These signs include:
- Feeling alert and rested throughout the day, no memory loss, stable mood and appetite
- Waking up easily after every block of sleep, little-to-no sleep inertia
- Falling asleep easily, having a short sleep onset (a few minutes for naps, <15 minutes for cores)
- Naturally waking up without alarms. This sign usually requires sticking to a schedule for a long time, and can never be met on the extreme schedules, thus isn't a necessary criteria of being adapted.
- Having increased dream recall and much denser naps, which usually feels long. For some people with a naturally low dream recall ability this sign might never appear, thereby being an unnecessary criteria too. Worth mentioning, it is possible to initially have dense REM dawn naps on some extreme schedules such as E3.
A sleeper usually is considered adapted to a schedule after 1-2 weeks of the adaptation criteria being stable.
Alternative adaptation models
It was noticed by some polyphasic sleepers that sometimes this adaptation model might not match the real experience. This section describes a few types of such cases.
Some people reported easier adaptation, usually almost without noticing Stage 3 or intense sleep deprivation symptoms in other words. Usually this is the case for non-reducing schedules with a structure, which is close to natural. The examples include Biphasic schedules (BiphasicX in particular) and sometimes other more exotic forms, usually also non-reducing. This actually is still on of the cases of the 4-stages adaptation model, being much milder because of the lower amount of sleep debt.
Other case was reported by some sleepers, a difficult start of the adaptation, with the signs gradually getting more and more mild as time goes. This case was met both on extreme schedules and on the easy ones, usually with pre-existing sleep deprivation and random sleep. This phenomenon can be explained by partially or fully skipping Stage 1 and 2, thus starting from the most difficult part. Worth noticing, this adaptation type usually has the same length as the standard one.