For many of us, it's very counterintuitive to think that 2-3 hours of sleep can meet the same biological needs that 7-9 hours can. To consider this a valid possibility, we must first examine why we sleep. Is it to rest our bodies? No. Our bodies can rest adequately while awake,1 but we still need sleep. Recent research suggests that the purpose of sleep is to repair and reorganize the brain.2
Now, let's play make-believe. =)
You live in a huge library. You are responsible for the entire library, and your job requires you to spend most of your day outside the library, collecting interesting and informative pieces of paper from everywhere you go. Every once in a while you drop by the library and dump everything onto the floor. "I'll organize it later," you say. Then, at the end of the day, you come back and start to sift through everything. You sort, you file, you consolidate, you associate, and you do it for nine hours straight because there's a lot of paper on the floor. When you're finished, you go back out to collect more.
One day, your boss tells you that every four hours you must return to the library for half an hour. While you're sitting there you think, "This is useless... it's not that messy in here, and I could be out collecting more papers." Then at the end of the day your boss tells you that you may not stay in the library to organize at night; you must go out and find more papers. What?? "If he wanted more papers, why didn't he let me get them during the day instead of sitting in the library doing nothing every few hours?" you say to yourself. This frustrates you greatly, but you don't want to get fired, so you leave to collect more papers.
When you return, you dump everything on the floor as usual. "This place is a mess," you think. "I wonder when the boss is going to let me organize all of it..." After a while, you realize that the half-hour stretches in the library are the only time you will be able to organize. You can't possibly keep up with this huge mess in only half-hour sessions, so you start throwing things in the trash. It takes you a couple of weeks to get everything either thrown away or put away on your new schedule, and when you finally finish you sigh with relief. Back to normal!
But you soon realize that things are different. When you enter the library every few hours with a stack of paper, you simply file it and go. The complexity of the task has greatly diminished, as there isn't a huge pile of paper in the floor. All you have to deal with is the paper collected in the past few hours. Now your library requires less total attention each day, and it stays relatively free of clutter at all times. Maybe your boss knew what he was doing after all?
This "library model" is pure speculation on my part, but I believe it represents the processes of the brain during the adaptation to polyphasic sleep. It certainly explains why several polynappers perceive a boost in mental clarity3-5 and why sleep deprivation causes impaired memory and cognitive ability.6 If the purpose of sleep is indeed to repair and reorganize the brain, I propose that this process becomes increasingly complex with more time spent continuously awake, and that the limit of its complexity marks the beginning of the cognitive effects of sleep deprivation.
1. The Phenomena of Sleep by Jim Horne:
"Humans can usually rest and relax quite adequately during wakefulness, and there is only a modest further energy saving to be gained by sleeping. We do not enter torpor, and the fall in metabolic rate for a human adult sleeping rather lying resting but awake, is only about 5-10%."
2. Sleep Found to Repair and Reorganize the Brain by William H. Cromie:
"Our data are consistent with the idea that sleep is primarily devoted to the critical activities of repair and reorganization in the brain, not the whole body, and that this reorganization probably includes learning and memory,"
3. Polyphasic Sleep Log - Day 120 by Nicholas Powell:
"One of the most noticeable aspects besides feeling more awake, adjusted, aware, alive, vibrant, and energized is the fact that the mental chatter noise disappears completely. No more mind clutter and continuously having that background noise of worry and going over problems."
4. Polyphasic Sleep Log - Day 21 by Steve Pavlina:
"The alertness and energy are there, but there’s something else too. The best way to describe it is to say that my mind feels a lot less noisy. It has become exceedingly calm, like a still lake. Somewhere along the way, I seem to have lost the chatterbox in the back of my mind. Now there’s a feeling of mental stillness, like the background mental noise has been turned off... Now when I sit down to work, I feel as if I’m working with deeper focus, clarity, and speed of thought than ever before."
5. After Adaptation by Jeff Seely:
"The post-nap state of mind was especially effervescent and unconstrained. My thoughts would flow faster than normal. If you have ever attempted difficult math proofs before, then you’re probably familiar with the frustration of hitting a mental block. It’s like writer’s block for mathematicians. I found that if I worked on my math problems after a nap, I usually experienced more lucrative thought processes, which helped get past mental blocks."
6. Neurocognitive Consequences of Sleep Deprivation by Jeffrey S. Durmer:
"Specific neurocognitive domains including executive attention, working memory, and divergent higher cognitive functions are particularly vulnerable to sleep loss."