In preparing to experiment on how to sleep less, I could not help but take a look at polyphasic sleep (note: I make a distinction between Polyphasic and Biphasic sleep here; see below for more). If you listen to the proponents of the technique (including people whom I respect, such as Tim Ferriss), a polyphasic schedule is a way to sleep significantly less and be just as awake (if not more so). This is supposed to be accomplished by adjusting the body’s natural rhythm to a series of short naps rather than a single block (also known as “monophasic” sleep). In other words, instead of sleeping 8 hours at night, you take a single 20-minute nap every 3 hours (on the so-called “uberman” schedule).
Eventually I decided not to include “true” polyphasic sleep in the experiments I conducted on myself (more on this below). The deciding factor was this article written by Dr. Piotr Wozniak, as well as this follow-up. If you are considering polyphasic sleep I highly recommend that you read both articles in-depth before doing so. Wozniak is a true scientist whose research on memory I have followed closely, and try as I might I cannot find a similarly reputable scientist in the polyphasic-camp to rebuke his arguments.
A few things that stick out to me:
- The human body has adapted to follow a natural circadian rhythm (24 hour light/dark cycle). Experiments have shown that this cycle can be expanded slightly, sometimes comfortably up to 26 hours, and anecdotes assert that some people naturally have a longer rhythm. However there is no evidence to support the idea that we can simply reject the sleep/waking cycle that humans have evolved. Our brains actually change their chemical balance to fit this cycle (eg, melatonin production).
- The effects of sleep deprivation are pretty bad, and if you watch videos of people attempting polyphasic sleep most of them are very clearly suffering from these symptoms after a few days.
- Having used tools such as the Zeo personal sleep coach to precisely monitor my own sleep cycles, I sincerely do not believe that sufficient REM / deep sleep can be fit into the nap schedules suggested by polyphasic sleep.
- As Dr. Wozniak points out, despite sincerely looking he has yet to find a documented case of someone successfully adjusting to a polyphasic schedule for a long period of time. Everyone who contacted him eventually gave up.
“Biphasic sleep” is just a fancy way of saying “afternoon nap” (“bi” = two, so you sleep two times a day). Polyphasic sleepers are fond of pointing out that lots of famous thinkers were ardent nappers. This by itself may not be a good reason, but it is a well-known fact that sleep is largely responsible for consolidating knowledge and generally restoring the body. In fact, there are published research papers which make definitive claims such as “[nappers] had higher cognitive scores and lower stress levels.” Even if it means sleeping slightly more in total each day, this sounds like a pretty good trade-off to me.
Check out my experiment on sleeping less and doing more to hear more about getting more from your sleep.