My summaries of the book Brain Rules continue...
Chapter 7: Sleep
Rule #7: Sleep well, think well.
We spend about a third of our time on the planet sleeping. Those few people who have "Fatal Familial Insomnia" and cannot sleep eventually die.
Randy Gardner, the father of sleep research, came to the conclusion early on that we have two opposing drives inside us with regard to sleep. Both of them are active all the time, whether we are awake or asleep. The one is the "circadian arousal system" (process C). It tries to keep us awake. The other is the "homeostatic sleep drive" (process S). It wants to put us to sleep.
Neither of these "armies" ever win the war. They lead us through a rhythm of being sleep and awake, and this rhythm takes place whether we are in a cave or outdoors. After 16 hours of active consciousness, process C will generally lose to process S. Eight hours later, process S usually loses and we wake up.
We do vary a little in our sleep needs and preferences. About 1 in 10 are "larks" whose bodies prefer to get up at least by 6am, the early birds. They're most alert about noon. About 2 in 10 are "owls" whose bodies want to stay up to all hours of the night. They're most alert about 6pm. The rest of us, about 7 in 10, are "hummingbirds" who are somewhere in the middle.
Sleep research has shown that those cultures that institute naps have recognized something research has substantiated. Humans do well to have an afternoon nap. Audiences lose attention. There are more traffic accidents than at any other time of the day. A 30 minute nap in this zone of the day significantly improves productivity.
Sleep helps learning and lack of sleep hurts it. Allowing someone to sleep on something improves insight, as much as tripling the benefit of learning. In short, "Sleep is rather intimately involved in learning" (163). Apparently, the brain consolidates its learning during sleep.
Medina ends the chapter with some possible suggestions. First, work schedules would optimally match "chronotypes" (larks-owls). "Twenty percent of the workforce is already at sub-optimal productivity in the current 9-to-5 model" (165). During teenage years, more individuals are owls than even in adulthood, suggesting that high school shouldn't start too early in the morning.
Creating space for employees to have an half-hour nap in the afternoon would probably increase their performance 34 percent. Finally, sleeping on things will generally improve our learning.