Stacy’s Book Note: The Secret World of Sleep: The Surprising Science of the Mind at Rest

Penelope Lewis heads the Sleep and Memory Lab at the University of Manchester in England and is the author of the book The Secret World of Sleep: The Surprising Science of the Mind at Rest (available on my Bookshop and Amazon*). The book has a wealth of scientific detail on sleep its relationship to the brain. I’ve tried to distill what is most useful for busy women and parents here. If you’d like more information on the book, you can also listen to an NPR Fresh Air interview.

Why sleep is so important

Using other sources, I’ve drafted an article on various reasons why sleep is so important. (Please subscribe to my newsletter!) Since Penelope Lewis’s book focuses on the brain, her reason is simple:

Sleep is sometimes referred to as the best cognitive enhancer on the market—meaning it beats all the drugs hands down. It may even be the key to superior IQ.

There are two ways in which sleep seems to do this:

  1. “Slow wave sleep resets the whole system by globally downscaling synapses (in other words, by gradually weakening or de-potentiating them). This downscaling not only makes space for new learning, it also removes noise and (assuming the important information has been encoded more strongly than unimportant information) increases the ratio between that important information and noise.”
  2. “[During REM sleep,] the sleeping brain is somehow freed of constraints and can thus create whole sequences of free associations. This is not only useful for creativity, it is also thought to facilitate insight and problem solving. It may even be critical for the integration of newly acquired memories with more remote ones.”

Nap tips from The Secret World of Sleep

If you want slow wave sleep to strengthen your neural representations of specific bits of knowledge, then it would be sensible to take a nap in the afternoon. On the other hand, if you want to strengthen emotional memories, it might be better to sleep longer in the morning, or take a morning.

Bed tips

One of the biggest influences on how you sleep is how you actually feel about your bed and bedroom. These should be comfortable, not too brightly lit, and strongly associated with sleep. Sliding into a cozy bed in which you only ever sleep (and maybe make love) sends all the right signals to your brain when it is time to switch off.

Winding-down tips from The Secret World of Sleep

A counterintuitive strategy for getting your body to cool down at just the right time is to heat yourself up a little before going to bed. A hot bath [or shower] starting about an hour and a half before bedtime is one of the best ways to ensure you’ll fall asleep.

Screen tips

You really shouldn’t use [televisions, computers, and devices that emit blue light] for the last three before your sleep… If you insist on using a smart phone or computer, then the screen should be covered with an orange filter, or you could install software which adjusts the screen to cut down blue light.

Waking tips from The Secret World of Sleep

Very dim red/orange lights which gradually come on, starting about half an hour before the alarm goes off, can make it easier to wake up…. Half an hour after the alarm sounds the room and bathroom should both be bathed in strong light…. If possible, it is best to make sure you are exposed to bright blue light for at least 30 minutes every morning.

Further information for parents

Penelope Lewis clearly provides a lot of information that we can pass on to our children. Here are links to additional articles on how we should talk to our children and to our teens about the importance of sleep and encourage them to sleep.

How are you sleeping? What do you find helpful?

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*Some of the links on this page are “affiliate links” where I receive a small commission from any purchases at no cost to you. Some of these funds will be donated to organizations supporting women and girls.