Introduction

Minimum sleep threshold is a very important parameter for well-being, especially in the context of polyphasic sleeping. By definition, it is the minimum amount of sleep duration each day to sustain performance for an extended period of time¹. Knowing that there is a limit will help specifically new polyphasic sleepers pursue realistic goals while reaping benefits of polyphasic sleeping. 

Minimum Total Sleep

Dr. Claudio Stampi, a polyphasic sleep researcher, has coined the term “sleep quantum” to describe the minimum sleep duration humans should get each day to optimize performance¹. The tunnel becomes very narrow because as sleep duration reduces, sleep stages become more important. Moreover, there is also evidence for increased sleep efficiency with less sleep. Stampi concluded that polyphasic sleeping strategies is possibly the only way to achieve a lot of sleep reduction without sacrifice of health. 

According to Stampi, the minimum total sleep time per day for normal monophasic sleepers (around 8 hours of monophasic sleep needed per day) with the help of polyphasic sleeping is approximately 4 hours¹. The community’s observations support this conclusion.

General Rules for Polyphasic Schedules

Thus, regardless of our wishes, we still have to sleep for a certain amount every day. When choosing a schedule, you should consider the “Minimum Total Sleep”. When you add up your daily requirements for both REM and SWS, the final number often falls between 3 and 4 hours. NREM2 is also necessary to some extent, as a transitioning phase; however, the duration of NREM2 can be very low on extreme schedules.

Let’s go through the guidelines. Note that the table does not account for extended versions. 

Polyphasic Schedules	Below Minimum Sleep Total (< 4h TST)
Biphasic	No schedules
Everyman	E4, E5, Trimaxion
Dual Core	No schedules
Tri Core	No schedules
Flexible	SPAMAYL
Core-only	No schedules
Nap-only	All schedules

Table 1. Sleep totals of polyphasic schedules

Some people may also have (significantly) lower sleep requirements. This is an advantage that facilitates adaptation to more extreme schedules compared to the average population. They are mostly short or perpetually insomniac sleepers. Contrary to regular 8h monophasic individuals, they may be able to adapt to schedules like E4. 

Thus, with all reasons above, average sleepers should not cut below 4 hours total sleep each day for long-term health effects. 

Personal Sleep Requirements

Aside from the general rules, it is possibly even more important to know your own sleep requirements well. This is because the general rules may or may not apply to you at all. This section focuses on different assets of personal sleep requirements. 

The only way to know your sleep stage duration is by using a reliable sleep tracker. Examples include the Zeo and Olimex. 

Light or Heavy Sleeper

Subjectively, you may be able to tell if you are a light or heavy sleeper. This may tell your sleep stage duration, but only tentatively.

• For example, a light sleeper may spend more time in light, REM sleep and less in SWS.
• A heavy sleeper, on the other hand, often struggles to wake up in the morning or any time at night. They usually sleep very soundly, and may have poorer dream recall. 

Short Sleeper

Objectively, check if you are a short sleeper. There are a couple things to note:

• If you naturally sleep only 6h or less a night for a long time and have no health conditions, you are a pure short sleeper. As a result, you may expect a normal SWS baseline (~90m on average) daily. You likely also have a lower REM need than regular sleeper. 
• If you sleep 5-6h during the weekdays but sleep a lot more in the weekends or holidays, you are NOT a short sleeper. You are only sleep deprived and likely so for a long time.  
• You feel well with a normal sleep duration (e.g, 7-9h) like any other average sleepers. However, your SWS and REM needs are naturally lower than average (e.g, 70m SWS and 75m REM daily). This is another form of “short sleeping”, except that you need to pay attention to any medical conditions that may ensue.

1. If you can naturally perform at your best on a daily basis with less vital sleep, then there is nothing to worry about.
2. Otherwise, you may need to find ways to increase your vital sleep percentage. 

Vital Sleep Totals & Scheduling Guide

Vital Sleep Total Duration (REM + SWS, hours)	Minimum TST on Polyphasic Sleep Schedules
5	Extended schedules, at least ~6.5h sleep
4.5	Extended schedules are preferred, at least 6h sleep
4	Extended schedules are preferred, at least ~5.5h sleep
3.5	At least ~4.5-5 sleep
3	At least ~4h sleep
2.5	At least ~3.5-4h sleep
2	At least ~3-3.5h sleep
Less than ~2	Radically reduced schedules

Table 2. Vital sleep totals on polyphasic schedules

Repartitioned sleep schedules that do not have available room for all necessary vital sleep stages are extremely difficult to adapt to. These have an extraordinarily low success rate, since it requires both a high cycle depth and a high level of compression. Extreme sleep compression may also leave out some percentage of vital sleep. Moreover, the long-term sustainability and health risks of these schedules are questionable. Any oversleeping on these schedules would immediately destabilize them.

Note that a lot of teenagers and physically active people often require at least 4 hours of vital sleep daily. Because it is impossible to completely remove light sleep from any schedules, it is important to spare some room for light sleep transition. 

The community prioritizes maintaining the same amount of vital sleep on a polyphasic schedule as on a monophasic schedule; therefore, the table is designed with the intent to reflect on the importance of vital sleep stages. They are important for a reason! 

Main author: GeneralNguyen

Page last updated: 19 January 2021

Reference

1. Stampi, Claudio. Why We Nap : Evolution, Chronobiology, and Functions of Polyphasic and Ultrashort Sleep. Birkhauser, 2014.