Isolated sleep paralysis and polyphasic sleeping


This blog post details the possibilities of sleep paralysis in polyphasic sleep (mostly during adaptation phase) and explanations of how frequently it appears during the polyphasic schedules in the current system. There are no direct research outcomes that draw a perfectly conclusive correlation between these two sleep phenomena, so any conjectures and reasonings presented in this blog post should be taken with a grain of salt. More research is needed in this area. 

Preliminary Introduction

Experiencing a sleep paralysis is not an uncommon phenomenon in our daily life that may occur during our slumber from time to time. Encounters with sleep paralysis are usually remarked as unpleasant at best, and nightmarish at worst. Common descriptions of sleep paralysis include, but not limited to visualization of demonic or otherworldly physical beings in the bedroom, or even lying right next to the sleeper. Aside from these terrifying hallucinations as our imagination runs its course, sleep paralysis is also tied to immobility of movements and absence of speech during the event. In this blog post, the focus is on isolated sleep paralysis, a type of paralysis that occurs right after a sleeper starts sleeping or after waking up. These encounters are usually random; however, there has been some research on sleep that can give some insights into isolated sleep paralysis’ contributors, causes and how it is related to polyphasic sleeping. 

At face value, it does appear that sleep paralysis is not common in polyphasic adaptation, and possibly not affected by human activities. Regardless, it is safe to assert that an average polyphasic sleeper will have a small chance, if there is any, to be faced with sleep paralysis during polyphasic adaptations to any of the schedules in the current system. 

Factors that allegedly introduce sleep paralysis

1. REM wakes & interrupted sleep:

Isolated sleep paralysis was observed using a method of interrupting the monophasic sleep pattern of healthy participants and waking them up after SOREM and a couple minutes of REM sleep1. No NREM or SWS wakes were reported to induce sleep paralysis since there were no apparent signs that suggest otherwise2. What is more intriguing is that the distribution of REM sleep and SOREM circadian-wise (naturally and not with artificial lighting control) also factors in the frequency of sleep paralysis. It is common knowledge that NREM/SWS dominates the first portion of the night (9 PM to midnight) and REM dominates the second portion as the night progresses toward dawn. However, sleep paralysis incidents were dictated to occur as often as possible without any time cues1 and only around 4 AM with controlled lighting environment3. The drawn speculation is that a more REM-abundant time frame in the day can help mitigate sleep paralysis’ occurrence (such as dawn) as REM density is higher and natural for the body to get. 

The interrupted monophasic sleep method bears some resemblance to the schedule Zoidberg (see Unadvised Scheduling for more information) which is a failed experiment. Sleep deprivation is kick-started in this sleep model quickly, and as sleep is chopped into some 20m nap chunks, the body fails to get enough REM and SWS. REM wakes built up within just 2-3 days according to the creator of the schedule, Dr. Zoid from the Discord community who reported to experience muscle discomfort that persisted throughout the duration of experimenting Zoidberg (but there was no specification of whether that was actually sleep paralysis or purely sleep deprivation). However, the experience seems to line up with the methods practiced in both aforementioned experiments, as muscle discomfort, in a vague way may resemble sleep paralysis where muscles cannot be moved around, or suggest trouble controlling them. 

2. Chaotic circadian rhythm (e.g, night shift):

Regarding sleep paralysis encountered by night shift nurses, only 12% of the subjects3 were reported to experience some higher degree of paralysis especially when dawn approaches and find it more difficult to stay awake at night and cognitive impairment during nighttime. The difference is that sleep paralysis incidents are focused around morning (dawn/the start of the day) rather than all across the board like in the 2002 study. This is reasonable because of the pre-establishment that sleep paralysis is induced in REM periods, which are abundant around morning time. Specific data include lowest alertness level, body temperature, physiological and biological functions around 4 AM. Circadian-wise, these details match the body’s need to rest and the necessity to be in deeper stages of sleep for recovery – these are sleep-inducing cues. The resistance to resting (which is very important why we sleep at night) causes the deterioration of sleep quality, resulting in several impairments in bodily functions that have been widely acknowledged in night shift workers, or at the very least, these workers show higher cardiovascular risks, etc. 

3. Tolerance & sensitivity to changes in sleep patterns:

This is an individual factor and varies from case to case1. The general pointer is that people who have experienced sleep paralysis have lower tolerance to changes in sleep patterns. This is conjecture material, so it requires more data for further conclusions. Theoretically speaking, it might suggest that those who do not have trouble going back to sleep after an interrupted wake tend to have better overall sleep quality as the sleep is patched to be continuous again. On the other hand, those who cannot go back to sleep after being woken by stimuli tend to have lighter sleep and susceptibility to insomnia (which is a result of stress caused by the build-up of lost and interrupted sleep) and more intermittent wakes. The lack of “flexibility” indicated in this article (flexibility in this context refers to the ability to adapt to different sleep environments) supports this perspective. This remains a very indirect correlation and needs further findings to confirm.  

4. Sleep deprivation/REM deprivation:

Back to the night shift nurse study, signs of sleep deprivation were clearly documented (struggle to stay awake, high level of sleepiness) just like those in polyphasic sleep adaptation, which leads to the lack of REM sleep (SWS as well but REM is the primary focus for the topic). An interesting observation from the study is that partial sleep deprivation is a result of night shift work and it reduced daytime sleep of the nurses. Consequently, it is possible to hypothesize that REM sleep deprivation in general can be correlated to sleep paralysis. 

Even though there was no specification of whether any of the nurses were practicing or had practiced any sleep pattern other than monophasic sleep by the time the experiment was conducted, it can be inferred that they were monophasic and had to reduce their monophasic core length due to their occupation, since polyphasic sleeping simply did not fit their work schedule while requiring consistency during adaptation to make it work. It is also reasonable to assume that their sleep started after the night shift, which is anywhere from 7 AM to 9 AM. The outcome is the late wake into noon or early afternoon, and feeling of unrestfulness. Circadian-wise this REM peak region leads to the initial lower amount of SWS in the core and at one point the core sleep has to be lengthened to resolve SWS deprivation while also having to cover all needed REM amount. Granted the nurses are busy with daily commitments, their core sleep cannot be as long as that of a normal monophasic core length of 7-9h. As a result, reducing the core length by the end cuts into REM (and likely still incur lower SWS amount) and leads to partial, and potentially chronic sleep deprivation if prolonged enough. The paralysis incidents reported from the nurses occurred BEFORE their sleep, implying that under considerable sleep pressure and sleep deprivation, sleep paralysis can occur. 

5. Other determinants (e.g, age, race, gender, genetics):

No clear evidence has been compiled for these factors on sleep paralysis2. Other factors such as mental disorders, substance abuse, etc are also possible. More research is needed in this field. 

However, narcolepsy, which is part of genetic factor, is a suspect in developing sleep paralysis2. None of the subjects were having narcoleptic symptoms, not excluding the chance that they might have it in the future. Data and findings demonstrate that they do not exhibit the same SOREM and REM periods as in narcoleptic patients; however, they did exhibit certain elements that are similar to those in narcoleptic patients, namely the physical manifestation of sleep paralysis – the inability to speak, hallucinations, irritation and some kind of emotional swings such as fear, which are classified to be present in narcoleptic cases. 

Current anecdotal observations, reports and concerns in the polyphasic world

In the Discord and Reddit polyphasic community, sleep paralysis is rarely reported. From personal accounts and experience, there are only a couple cases of adaptation to more extreme schedules such as Bimaxion and Everyman 3 (no cases after successful adaptation were documented). Milder schedules such as biphasic, Everyman 2, Dual Core 1 and the likes contain no reports. The number is not comprehensive, due to the inconsistent amount of logs and personal preference of whether to report it or not. With such a small sample size, however, it can still be inferred that intense sleep deprivation and REM wakes do play some role in incurring sleep paralysis. Other factors such as diet, lifestyle, personal hygienes might or might not develop more frequent encounters with sleep paralysis, but no reports on this end are recorded from polyphasic sleepers. 

Furthermore, concerns with sleep paralysis do potentially spike during scheduling. Given that a research article on night shift nurses sparked some insights into sleep paralysis generated by messy circadian rhythm (missing night sleep, increasing drowsiness and decreased alertness at nighttime), it is reasonable to take this into account when scheduling a polyphasic sleep pattern. The favorable choice would be to focus on sleeping at night, or getting as much night sleep as possible, covering some or most of the graveyard hours (midnight to 8 AM). An even safer approach is to sleep at consistent times everyday or some flexibility within a small window of when sleep times start to have better control over circadian rhythm. Thus, third shift workers or any polyphasic schedules that have no sleep within the graveyard hours (see Scheduling section for more information) will likely have an increased chance to come across sleep paralysis, increasing fatigue, harder adaptations and prolonged sleep deprivation. It is also wise to stop adapting to a schedule if oversleeps keep happening, to recover from all sleep debt before more bad wakes (REM/SWS wakes) occur during adaptation. It seems that all in all, a reasonable sleep pattern combined with healthy life choices will lead to blissful sleep and shield sleepers from unpleasant events like sleep paralysis. 

Main author: GeneralNguyen

Page last updated: 21 January 2020

Takeuchi, T., Fukuda, K., Sasaki, Y., Inugami, M., & Murphy, T. I. (2002). Factors Related to the Occurrence of Isolated Sleep Paralysis Elicited During a Multi-Phasic Sleep-Wake Schedule. Sleep, 25(1), 89–96. doi:10.1093/sleep/25.1.89
Takeuchi, T., Miyasita, A., Sasaki, Y., Inugami, M., & Fukuda, K. (1992).
Isolated Sleep Paralysis Elicited by Sleep Interruption. Sleep, 15(3), 217–225. doi:10.1093/sleep/15.3.217
Folkard, S., Condon, R., & Herbert, M. (1984). Night shift paralysis. Experientia, 40(5), 510–512. doi:10.1007/bf01952412 

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