Polyphasic sleep:More with less?

It is a cliche that despite all the amazing luxuries, time-savers and other conveniences that we have in modern times, the average person still has little “free” time. The tasks we do seem to magically fill all available time so that we always want "just a few more hours". Polyphasic sleep schedules are proposed as a "solution" to this problem by increasing waking hours using shortened sleep and naps.

In terms of time management, what seems to be the case for me at least is that it's really a matter of just wanting to do even more of what I want, not a lack of getting to do what I want.For example, I enjoy watching Netflix with my wife at night. So if we decide to watch a show or two, that's a couple of hours that I can't write or read or play a game. Writing these articles generally takes between 3 and 8 hours in a week. Since I publish on Fridays, I usually "take a break" for the weekend, meaning most of that writing time happens Monday through Thursday. So in fact I get to plenty of things that I choose to do, but doing those things takes time away from doing other things that I want to do.

So for me the goal of something like polyphasic sleep is to shift portions of the waking hours to times which are more open to personal hobbies (writing, reading, gaming). For other people, I think it is just a matter of different prioritization of their time and/or less commitments (I admit that I frequently will procrastinate, which has the obvious effect of reducing productivity). As it is, I already operate with less sleep than I should -- I often go to bed around 12:30 to 1 and get up around 7, after a night of being up many times with my 6-month old daughter -- so I won’t be going from an abundant 8 or 10 hours to 4 or 5 hours. I already get approximately 5 hours.

What is polyphasic sleep?

Enter polyphasic sleep. The idea is to solve the “not enough hours in the day” problem by... adding more hours to your “day” (actually, crazy early in the morning). This is effected by lowering the number of hours that you sleep in the day. The total sleep hours can range from as low as 1.5 hours to up to 6 hours. For 6 hours you may think, “but I already get about 6 hours of sleep, how is this any different?” The answer is in the term “polyphasic”: you sleep in multiple sessions throughout the day, spreading out those sleep hours via naps and (usually) a longer “core” sleep. For instance, a popular schedule is “Everyman” which is set up with a three- or four-hour core sleep along with three 20-30 minute naps, for a total of 4-5.5 hours, which is not much lower to what I already get now (especially with a new baby).

What do studies say about polyphasic sleep?

This seems to be a tough question. As best I can tell, polyphasic sleep schedules would be classified as a form of "sleep restriction" as it involves less than about eight hours of sleep in a 24-hour period. It would not be classified as sleep deprivation as I understand the term because the wakeful period is not all consecutive hours. It seems that the majority of studies are related to “acute total sleep deprivation” where a person is forced to remain awake for 24+ hours at a time (Alhola 2003). It doesn’t seem that the results of those are directly relevant to something like polyphasic sleep with 4-5 hours of sleep out of every 24 hours (and rarely more than 4 hours awake at a time).

For someone in college, or who in general wants extra hours for studying, then from the studies alone it seems difficult to tell if polyphasic sleep would be effective. A 2008 study suggests that the mere act of falling asleep (even if briefly) “may initiate active processes of [memory] consolidation” (Lahl 2008). A 2012 study showed tasks that involve working memory are not overly affected by partial sleep deprivation, but “sustained attention” was (Lo 2012). So it might be difficult, if sleep deprived, to maintain attention, but it seems like the actual ability to understand and retain the information is not overly impaired. A 2003 study demonstrated that “lapses in behavioral alertness were near-linearly related to the cumulative duration of wakefulness in excess of 15.84 h” (Van Dongen 2003).

To that end, there is an informal online "test" available for assessing your "sleepiness". I found that previously when I took it, I performed worst right after waking up, which is apparently due to something known as "sleep inertia".

Is polyphasic sleep safe?

The natural question is whether this type of thing is safe. What does the science say? Is there added benefit on top of the “cost” of possible tiredness and odd stares from people as you scramble to find a nap spot? The 2003 review by Alhola et al found that, in general, cognitive impairment follows lowered sleep from sleep restriction, and that driving performance can be affected and likelihood of accidents (in simulations) increases after a few nights of restricted sleep. They cite one study (Belenky 2003) where performance on the psychomotor vigilance test (PVT) kept deteriorating in the group restricted to 3h a night, but stabilized (at a lowered level) very quickly for the 5- and 7h groups. As the review authors point out, this sort of restricted sleep (5 to 7 hours) probably represents a norm for many people who work full time jobs and have any sort of life or family.

But I would argue that polyphasic sleep cycles don't strictly fit into the normal view of restricted sleep which essentially assumes 20+ consecutive hours of wakefulness, which is not the pattern of most polyphasic sleep schedules -- a "core" sleep + regular naps, especially when you factor in the notion of "recovery sleep".

Recovery sleep

“Recovery sleep” is characterized as being of lower latency and higher efficiency as the body tries to gain back some of that last rest. My possibly-quite-unscientific hypothesis is that the regular naps act as a form of recovery sleep (especially considering the Lahl study above).

In the Belenky study they found that “During recovery, PVT speed in the 7- and 5-h groups (and lapses in the 5-h group) remained at the stable, but reduced levels seen during the last days of the experimental phase, with no evidence of recovery. Speed and lapses in the 3-h group recovered rapidly following the first night of recovery sleep; however, recovery was incomplete with speed and lapses stabilizing at a level comparable with the 7- and 5-h groups.“

It has been quite a while since I have had 7 hours of solid sleep in a night, so assuming that the naps are capable of acting as recovery sleep corresponding to a single day of partial deprivation, in theory polyphasic sleep may be similar to getting 7 hours a night.

My personal experience (aka anecdotal evidence)

I found that within the first couple of days I could fairly easily fall into a nice sleep and wake feeling rested within the 15 minute period. Same for the 3 or so hour “core” sleep... there ended up being very little of my normal lay-in-bed-for-thirty-minutes-trying-to-sleep issues.

I am considering re-embarking on my own experiment with polyphasic sleep (my first attempt ended a week in after I tried changing the schedule up at the request of my wife). My own goals are to be able to write more (blogging, articles), read more (fiction,non-fiction), study more (Greek) while not losing any time with my wife and two children.

Certainly if cognitive impairment is an effect then I am rather wary as my day job as a software engineer generally demands a certain level of focus and decent working memory. But it seems that if I already only get 4 to 6 hours of sleep a day, then doing it in a more controlled manner with naps throughout would actually be a net positive.

Conclusion

There are a limited number of waking hours of the day, and we all want to use that time in the most efficient manner possible. Polyphasic sleep proposes to solve that problem by reducing the number of sleeping hours while at the same time spreading out those hours to reduce prolonged wariness. In my own experience I felt like it was a workable system, and would like to retry it. The science seems mixed on the dangers or advantages because most studies are focused on acute sleep deprivation or single bouts of restricted sleep, rather than restricted sleep paired with naps.

I’m very interested in any reader’s experience with polyphasic sleep, or pointers to any additional studies which are directly relevant (especially if they address naps).

REFERENCES

LAHL, O., WISPEL, C., WILLIGENS, B. and PIETROWSKY, R. (2008), An ultra short episode of sleep is sufficient to promote declarative memory performance. Journal of Sleep Research, 17: 3�"10. doi: 10.1111/j.1365-2869.2008.00622.x

Lo JC, Groeger JA, Santhi N, Arbon EL, Lazar AS, et al. (2012) Effects of Partial and Acute Total Sleep Deprivation on Performance across Cognitive Domains, Individuals and Circadian Phase. PLoS ONE 7(9): e45987. doi:10.1371/journal.pone.0045987

Van Dongen HP, Maislin G, Mullington JM, Dinges DF (2003) The cumulative cost of additional wakefulness: dose-response effects on neurobehavioral functions and sleep physiology from chronic sleep restriction and total sleep deprivation. Sleep 26: 117�"126.

Alhola, Paula, and Päivi Polo-Kantola. "Sleep deprivation: Impact on cognitive performance." Neuropsychiatric disease and treatment 3, no. 5 (2007): 553.

Belenky G, Wesensten NJ, Thorne DR, et al. Patterns of performance degradation and restoration during sleep restriction and subsequent recovery: A sleep dose-response study. J Sleep Res. 2003;12:1�"12.