[No registration!] Is polyphasic sleep dangerous?

Sleep architecture changes

Sleep architecture changes

This part will be centered around how the sleep architecture changes when people adapt to a polyphasic schedule.


At this point in time, it is believed that reducing SWS or REM sleep leads to several negative consequences. SWS is the sleep stage where the glymphatic system is most active, and it’s during this sleep stage that damaged cells are repaired. SWS is also responsible for long-term memory consolidation, and REM sleep is responsible for several types of memory consolidation like procedural, spatial and emotional memory formation. Reducing these sleep stages is what triggers the feelings of sleep deprivation, and consistently reducing them for a long time can lead to negative effects such as immune system deficiency, obesity, cardiovascular diseases, diabetes and so on.

Both of these sleep stages are, because of this, classified as vital sleep stages. What that means is that they serve vital functions for the body, and reducing them leads to feelings of sleep deprivation and can really harm the body. This is also supported by the fact that when you miss out on sleep, the body will attempt to partially salvage the missed out SWS and REM sleep during the recovery, which doesn’t happen with light sleep.

Current situation

After establishing that reducing SWS or REM sleep leads to negative consequences, what is the situation with polyphasic sleepers? Well, the community has been working on a project called the “EEG labeling project”. The idea here is that some community members who attempt polyphasic schedules are interested in tracking their sleep stages so that they can see how their adaptations progress. This data is gathered and processed to determine exactly how the sleep architecture is going to be altered upon a complete adaptation. The project is still ongoing, but there are already some quite nice readings that will be shared with you.

This picture is an EEG reading from Crimson when he just started attempting the Everyman 1 schedule. After he had adapted to the schedule, this is one of the readings he got:

The amount of SWS that he had stayed relatively consistent, but the duration of REM sleep increased significantly at the expense of light sleep. This also matched with his monophasic need, so he was able to get all needed SWS and REM sleep from the schedule.

Another good hypnogram we can look at is from Feili. First, I want to tell you that his baseline monophasic requirements were around 90 minutes of REM sleep and 130 minutes of SWS. When he started his schedule, he clearly got less REM sleep than what he needed. However, after adapting, you can see that his REM has increased to account for almost all his need, with the rest of it coming from his naps that also contained REM sleep:

This picture is actually from his morning nap which at this point in time was almost overflowing with REM:

The future

In the future, the EEG labeling project is going to be continued and evidence for whether this repartitioning happens for several people or only a select few will be gathered and assessed.  So far, it seems like repartitioning is something that happens for many people. If you have EEG readings from before and after you started a polyphasic schedule that you can share with us, get in touch over the Discord. Even if your readings show that you get different amounts. That way, we can further this community’s understanding of sleep in general, and polyphasic schedules especially.

Changes in Light sleep

What does reducing light sleep entail? As established, after adapting to a polyphasic schedule, the same duration of SWS and REM sleep should be gained as when people are monophasic. But what happens to light sleep? First, it must be pointed out that light sleep is definitely going to be reduced after adapting to a polyphasic sleep schedule (bar non-reducing polyphasic schedules).

During an adaptation, the body is going through several different defence mechanisms to ensure that it gets the required amount of SWS and REM sleep, and this will be done at the expense of light sleep. The fact that this happens is somewhat telling about how the body treats light sleep, as a sort of filler type of sleep. This is also supported with the fact that light sleep doesn’t really build any type of sleep pressure. When you are missing out on SWS or REM sleep, your body is going to want to get more of it, eventually inserting the sleep type very early in the sleep, also known as SOREM and SOSWS to make sure that the needed durations of these sleep stages are gained.

But this is not a mechanism that happens with light sleep. When the duration of light sleep that you are getting is shortened, your body makes absolutely no effort to ensure that more light sleep is regained. In addition, this is a perfect opportunity to point out that when you have sleep deprived yourself, your body is not going to catch up on light sleep like it does with SWS and REM sleep. When you miss out on sleep, your body is going to sleep extra in order to make sure that around 70% of missed SWS is recovered, and that around 50% of missed REM sleep is recovered. But only 7% of missed light sleep is gained back, which supports the idea that it’s a non-vital sleep stage.

It should be pointed out that light sleep does serve some functions. However, there does not seem to be any VITAL functions associated with it. It helps with a bit of memory consolidation, especially memories related to movements (e.g, learning how to ride a bike), but it’s not anything vital. Light sleep is also responsible for acting as a wakefulness sustainer, which is one of the reasons why we need to add naps when sleeping polyphasically – the reduced light sleep doesn’t allow us to sleep as long and remain awake for as long as on monophasic sleep.

Also, there is another important thing to talk about: sleep spindles and k-complexes. These appear both in light sleep and SWS, and it’s been found that reducing these by too much can lead to the development of schizophrenia-type symptoms. So far, these symptoms have not been observed on a schedule where SWS isn’t reduced, or in other words, out of everyone that has adapted to a polyphasic schedule, no one has developed these symptoms. We actually have one case that developed schizophrenia-type symptoms from a polyphasic schedule, but that was because they stayed on the Tesla schedule for several months. Tesla schedule is not recommended and is only suited for very short sleepers, being very extreme in nature. 


What are some concrete points that people interested in showing that polyphasic sleeping is dangerous would have to find evidence for in order to make the claim?

  1. That SWS and REM durations are decreased after adapting to a polyphasic schedule.
  2. That reducing SWS and REM definitely leads to negative health effects.
  3. That reducing light sleep leads to negative health effects.

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