book talk

Book Talk: Why We Sleep

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Why We Sleep: Unlocking the Power of Sleep and Dreams

The book that has been sticking with me the most lately and coming up in conversations with people is called Why We Sleep by Matthew Walker.

Just as in my last book talk post, I wanted to share my thoughts on the book, because books are more fun when we can have conversations about them!

It’s no wonder that the topic of sleep would come up often in conversation. We all feel tired or have conversations with people who feel tired – probably more days than not.

Why is that?

Dr. Matthew Walker, a sleep scientist and professor at UC Berkeley, would tell you that it is because we don’t sleep enough, or sleep well enough.

Seems rather obvious, right?

But what blew my mind was all of the research study data that he had to share in his book on sleep, and all the ramifications on every organ and system in our bodies, on our ability to regulate our emotions, on our productivity, and on our relationships.

I said in my Goodreads review that I think this should be required reading for every person, starting with teens and going on up through adults.

Before I go on about all the ways I’ve been thinking about this book, I have a few caveats/disclaimers:

  1. This book will not necessarily help you get better sleep. It might stress you out if you’re not sleeping well, because you realize all the ways your lack of sleep (or quality of sleep) is affecting your life. (Seriously, not joking.)
  2. You may or may not agree with his stance on evolution (which he does discuss or mention frequently); however, the data that he and his peers have found on sleep and the ramifications for your life and society still apply, whether or not you agree on what he says about the history of sleep.
  3. This is a more data-heavy book. If you get bored with data, I can’t promise this will hold your attention. But I will tell you that Dr. Walker does an outstanding job explaining technical terms for people who aren’t in his field without dumbing it down, being annoyingly condescending, or confusing the reader.
  4. Apparently some people in the scientific community pushed back on some of Walker’s data in the book and said that he “misrepresented data” in some places. Here’s an article I found in case you want to learn more. As always, take what you read with a grain of salt: first, science is never a done deal (Galileo, anyone?), and second, it is possible to choose what data you present and how you present it.

I started out listening to this book on audio on my commute to and from work. I don’t recommend it! At least not the listening-while-driving part. Mostly because this book is (appropriately) a bit soporific. I would end up feeling sleepy while driving, which, as you’ll find out if you read the book, is a higher cause of crashes than even drunk driving.

One of the quotes that will stick with me from his book was this:

“I used to say that the three pillars of health are sleep, nutrition, and exercise. Now I’ve changed my tune: Sleep is the foundation on which the other two stand.”

Matthew Walker, Why We Sleep

This quote is probably one of the main messages of his book. He spends a chapter explaining the benefits of sleep for every system of the body, as well as the effects when we don’t sleep enough.

In the following chapter, he explains the benefits of sleep on the mind and creativity, as well as the ways inadequate sleep adversely affects our performance at work, in our relationships, and in our ability to creatively solve problems.

I enjoyed hearing about the studies that he and others have performed to test people’s problem solving abilities, their abilities to learn new things, and on their emotional capacity following full or not-full nights of sleep.

Unlike other texts I’ve read recently that just sound inflammatory and don’t explain the science, Walker is sure to explain when studies do and do not show causation. Sometimes I would find myself thinking, “That doesn’t necessarily mean causation, though!” right before he would say the same thing and then go on to explain the follow-up study that does support the relationship of causation between sleep and ____. However, please see disclaimer #4 above, and consider as you read the rest of what I write below.

To support his statement that sleep is the foundation on which the other two stand, he cited a study they did on exercise performance with and without full night’s of sleep. I found this interesting, because as a runner, I’ve anecdotally and unofficially found that I sleep better when exercising. I’m not alone in that “finding.” However, he says that while they do seem to affect each other, sleep seems to affect exercise performance more than the reverse.

He also said that one night of inadequate sleep adversely affects the body and mind FAR more than one day of not eating well or one day of not exercising.

Having read all of his explanations in previous chapters, I can easily believe that.

Here are just a few of the body systems that sleep benefits:

  • cardiovascular health
  • blood sugar regulation (not sleeping well makes a person’s blood sugar levels look prediabetic the next day!)
  • metabolism and digestion
  • and a bunch of others I can’t remember

Here are some of the mental and emotional functions that sleep supports:

  • problem-solving
  • muscle memory (which is actually a function of the brain) – musicians and athletes anyone? You perform better after practicing hard and then sleeping well!
  • Learning new facts, skills, and processes
  • Mood regulation – people are more irritated when tired (we know this from looking at tired toddlers, but he explains why)
  • Choosing challenging tasks versus simple tasks
  • Honesty – people are more likely to lie than tell the truth when they aren’t getting enough sleep (!!)
  • Memory
  • Cleaning out toxins, specifically the stuff that accumulates in the brain and is part of Alzheimer’s, from the brain each night
  • processing trauma and emotional difficulty through dreaming (the part on PTSD was compelling!)

Perhaps I was so absorbed by this book because I am also fascinated by psychology and neuroscience. He explained circadian rhythms and night owls vs morning larks. He talked about how the brain works during sleep. He explained how sleep affects some big-name diseases like Alzheimer’s, diabetes, and heart disease.

If that’s not interesting to you, then maybe this won’t be your cup of tea.

But I was also engrossed by the sociology he threw in here.

How we started sleeping less and less with the advent of electricity, and then the advent of devices with screens.

How studies show that starting school later, especially for teens, significantly improves their grades and performance on tests.

How our entire society supports not getting enough sleep, and that is dangerous to our health and our very lives.

Photo by Ivan Oboleninov on

This book was timely for me because, over the last few years, I have developed a firm distaste for busyness. And I have also developed a firm conviction that I want to order my life so that I am not in a constant state of sleep deprivation and being worn down.

If you are a parent of young kids, please hear me when I say that I know your life is not your own right now. I know that sleep deprivation is (or at least by all counts seems to be) a fact of life in that stage.

I also know that if you’re working night shift, you’re probably not doing so hot either.


I think a lot of us say that we aren’t getting enough sleep and feel like it’s out of our control when it actually isn’t. You are in control of when you go to bed, when you stop working, when you stop drinking coffee each day, when you turn off your tech, etc.

I feel strongly about rest in part because of my theology and faith.

Let me give you a quick run down of places in Scripture that discuss rest:

“In vain you rise early and stay up late, toiling for food to eat, because the Lord grants sleep to those he loves.” Psalm 127:2

I’m responsible for working hard and completing tasks, yes. But God is the one who ultimately provides for every need of mine, including the time I need to get things done (see also Matthew 6:25-34).

Ever heard of the “law” that an activity expands to fill whatever time is available? When I sleep enough, I have less time to get things done; yet they still get done. I’ve seen it over and over in my life.

“By the seventh day God had finished the work he had been doing; so on the seventh day he rested from all his work.” Genesis 2:2

God himself rested. And I don’t think it was because God was tired (other Scripture that talks about God’s nature seems to say that he doesn’t get tired like humans do). Rather, I think he was being the good teacher that he is and modeling for us how we should live.

“But the seventh day is a sabbath to the Lord your God. On it you shall not do any work, neither you, nor your son or daughter, nor your male or female servant, nor your animals, nor any foreigner residing in your towns.” Exodus 20:10

I’m not quoting this verse to get all legalistic on you. I think a weekly day of rest is what we were created for, and it also is an expression of trust and dependency on God.

When God instituted a day of rest for His people, the Israelites were wandering in the desert and were literally dependent on God for their daily food. Think about it – deserts are not a place we can grow our own food, or even hunt for much. And certainly not for a million or so people every day for 40 years.

Yet God promised to provide extra on the sixth day for what they needed for the day of rest on the seventh day. He wasn’t saying, “You have to rest cuz I say so, but good luck on having what you need for that day.” He was- and still is – Jehovah Jireh – the God who provides.

A professor of mine, freshman year of college, said something (or maybe it was said in the sermon we listened to in class?) that has stuck with me to this day:

“The Sabbath [day of rest] is when our to-do list is done, even when it isn’t.”

We know, as adults, that our to-do list is never done. Ever. Not until the day we draw our last breath – and even then, we probably will still have items on a list somewhere that haven’t been done.

Doing is part of life.

Doing is not life itself.

We’re called human beings.

I think it’s important to remember that in order to be, you don’t have to do.

Yes, we need a weekly day of rest to practice trust in God and recover from our work.

But we are also daily reminded of our dependency on God through our need for sleep.

Just like a day of rest, where we say we have “finished our work” even when we haven’t, nightly sleep is an expression of trust in God.

“In peace I will lie down and sleep, for you alone, Lord, make me dwell in safety.” Psalm 4:8

We lie down at night and fall asleep, knowing there are things we haven’t figured out or completed or solved, but also knowing that God will provide everything we need for the next day – including the time and ideas to get things done.

Sleep is an expression of trust in God, because we aren’t in control as we sleep. We aren’t aware of our surroundings. We can’t defend ourselves as we sleep or get ahead of the competition.

But as we express our trust in God through sleep, even when our to-do list isn’t done, God gives us the beautiful gift of restoring our bodies and minds through the way he made sleep to work, so that we have renewed energy for the tasks and relationships of the day ahead.

It’s so good to serve a God who loves us so much that He provides for us and encourages us daily to remember that He is trustworthy and in charge so we don’t have to feel the weight of the world on our human shoulders.

I don’t know about you, but being invited to trust and fall asleep makes me want to just exhale a big ol’ breath.

Photo by Aditya Bose on

Just like this blog post, Why We Sleep doesn’t promise to solve all of our sleep problems. In fact, the book has a surprisingly small percentage dedicated to giving solutions to sleeping more and better.

But I suppose sometimes we don’t need chapters upon chapters. We just need simple principles to live by and to practice as we go through seasons of life.

For instance:

  • not drinking caffeine for 8 hours before bed
  • going to sleep and arising at the same time, respectively, each night and morning – consistently
  • using dimmer lights as it gets closer to bed time
  • keeping the room cooler so your core body temperature can decrease appropriately
  • keeping your room dark and quiet
  • And adding one from me: taking three deep, slow breaths as you call to mind God’s goodness, faithfulness, and provision. Maybe even quoting yourself Psalm 4:8 (above) to remind yourself that God is the one who makes you secure and safe. Not you.

Whether or not you decide to read Why We Sleep and find out some of the intriguing things about the mystery of sleep, I hope your sleep is sweet and long.

Rest is, after all, part of our design and a gift from the One who is most capable and trustworthy.

Have you read this book?

What are your thoughts on sleep?

One thought on “Book Talk: Why We Sleep

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