Do you ever think about sleep? Not about falling asleep but the details of your sleep. Until recently, I thought I had it all figured out. I’d shut off all my electronics before bed, and sleep for 8 hours a night. I’d use Sleep Cycle (a mobile app) to make sure that I was waking up at the most optimal time and I wouldn’t take a single nap during the day. That sounds like a great routine, right?
01 | My Discovery of Biphasic Sleep
A few days ago, I came across some new information. Psychiatrist Thomas Weir performed a study on 8 men who were subjected to 14 hours of darkness for a month. He found that, initially, the men would sleep for a single block of 11 hours, in order to make up for the sleep debt that they had accrued in their normal lives. Eventually, these men began to naturally sleep for 4 hours, wake up for 2 hours and then sleep for another 4 hours. This is known as biphasic sleep.
Roger Ekirch, a historian, argues that our ancestors had biphasic sleeping patterns. They used the time in between their first sleep and second sleep to do many things such as write, meditate, pray, or do chores. So what happened? Why does the vast majority of the Western world follow monophasic sleep patterns (sleeping straight through the night) as opposed to biphasic?
To understand that, we have to go back in time to the Industrial Revolution. Ekirch believes that before the Industrial Revolution, biphasic sleeping patterns were the norm. However, the revolution marked the beginning of productivity and, in this case, productivity literally meant producing more units of something in a specific time frame. The world began to move faster, and the growth rate of technology increased. We invented artificial light, and so began the disruption to our natural circadian rhythms.
02 | Napping, The Biphasic Alternative
Breaking our nightly sleep up into two equal blocks is not the only form of biphasic sleeping. Sleeping for a longer period of time at night and then taking a nap in the afternoon is actually a fairly common practice in the Eastern world. In China, workers sometimes take a break after lunch to nap; it’s actually a constitutional right! Spain has had a long tradition of midday napping, known as the siesta, although this idea may be declining in the modern day. In Italy, shops close for an extended lunch which allows shop owners to relax and sometimes catch a nap. I believe this is called a Riposo.
On the other hand, Western companies are also starting to believe in the power of napping. Companies such as Uber, Google, the Huffington Post, and Ben & Jerry’s have started to create designated napping rooms or pods for their workers as they believe it improves productivity and quality of life. According to the Journal of Sleep, U.S companies suffer a loss of $63 billion due to sleep deprivation.
So..if I’ve convinced you that naps are important, how long should you nap for?
03 | How Long Should You Nap For?
According to Sleep.org, a 20 minute nap, also known as a power nap, can make you more awake, more energetic, and have positive effects on your mood. This also the most practical length of time that the average person can nap for in the Western world.
As your nap length moves into the 30-60 minute range, the benefits drop off. You’re more likely to feel groggy and upset upon waking due to the effects of sleep inertia.
However, a 90-minute nap is one full sleep cycle and so you’ll wake up feeling refreshed with improved memory and creativity.
Some studies show that a nap as short as 6-minutes may also improve your memory.
Studies also show that individuals who take a 10-20 minute nap see benefits almost immediately, where as individuals who nap for longer periods of time see delayed benefits. The same study also showed that naps taken after 6 or 18 hours of being awake had more benefits than naps taken after 30, 42, or 54 hours of being awake. In short, a nap can’t makeup for a bad sleep routine.
In conclusion, it seems that the 20-minute power nap combined with a good sleeping routine will produce the greatest benefits for the most people. However, a 90-minute nap may prove to be better if you want improved memory and creativity. I think in some rare cases, you might want to try biphasic sleeping at night. I can imagine that sleeping for 4 hours and then waking up in the middle of the night to work for 2 hours can really improve creativity. But, I think this type of sleep schedule won’t be as practical for many people.