Why we Sleep: Unlocking the Power of Sleep and Dreams by Matthew Walker, PhD

by Amy McGarry


Sleep, glorious sleep! If you’re like me, you’ve always known that getting enough sleep is as important to your health as getting enough food and water. One night without adequate sleep leaves you feeling foggy, less sharp, maybe even in pain, like you’ve been hit by a Mac truck. Yet, do we really understand the purpose of sleep? What function does it serve? Why in the world would nature insist on us lying in a coma-like state for one whole third of our lives?


In Why we Sleep: Unlocking the Power of Sleep and Dreams, Matthew Walker, PhD, shares the latest research in neuroscience explaining what scientists are beginning to understand about sleep. Spoiler alert: They still don’t know exactly why we sleep. What they have discovered is all the amazing magic occurring in the brain during sleep, and the tragic results of skimping even slightly on the prerequisite seven to eight hours.


One finding has to do with sleep and learning, specifically, memory. Walker goes into great detail about countless experiments with electrodes on sleepers, both human and rats, illustrating convincing data that while memories might be formed in waking life, being able to access them again is a result of sleep. 


Everyone I know these days complains about their memory. We often assume memory loss is related to aging or information overload. But after reading Why we Sleep, I can’t help but think it’s connected to sleep, that is, lack thereof. 


Furthermore, the effects of sleep on learning are profound. My favorite anecdotal example is about a famous pianist, who recounted practicing and practicing a piece late into the evening, but he could simply not master it. Giving up, he went to bed and slept a full night. The next morning, as you’ll be able to predict by now, he was able to play the piece flawlessly. That’s the power of sleep on learning. 


What’s disturbing to me about this as a parent, is that we intentionally deprive our teens of sleep by insisting on an early start to the school day, then expect them to learn at their highest capability. It’s no revelation that teenagers’ natural circadian rhythm is that of the night owl. An adolescent’s brain starts to rev up in the evening and it’s physically impossible for them to fall asleep in the earlier evening hours.  After reading Why we Sleep, I wondered that teens can learn at all with their poor sleep deprived brains. 


Even more disturbing are the findings on sleep deprivation and health issues. Cancer. Heart disease. A shorter life. According to Walker, these can all be connected to lack of sleep. Especially frightening to me, after watching my mother’s decline as a result of Alzheimer’s, is the relationship they’re seeing between inadequate sleep and Alzheimer’s disease. 


While Walker drives home the point that too many people make a choice in their sleep deficits, or, like teenagers, are forced into inadequate sleep, he neglects an issue that can affect half of the population. As a woman of a “certain age”, I have dealt with sleep issues resulting from hormonal changes. Countless female friends of mine share the same complaint. Walker completely ignores this issue.


Of course, countless men suffer from insomnia as well, losing the health benefits and feeling miserable as a result. While Walker provides a whole list of recommendations for achieving a better night sleep, none of these are earth-shattering or even new. Most importantly, according to this book and the National Sleep Foundation, is having a consistent time for falling asleep and waking up each day. Other recommendations include avoiding alcohol and keeping the bedroom a cool 65 degrees. 


One fascinating point regarding the relationship between body temperature and sleep involves the seemingly contradictory practice of warming the hands and feet to cool the body’s core and promote sleep. No wonder I fall right to sleep when I put my icy cold feet on my husband’s warm legs at night!


My favorite laugh-out-loud image from the book came from reading about the experiment to test this. Walker describes how scientists “gently warmed” the little paws of mice to learn this cooled the body’s core, helping them “drift off to sleep” much faster than the warm-pawed mice. (Okay, I have to admit it. They were rats, not mice. But doesn’t the image of mice seem nicer?)


The reading is heavy at times. This is brain science, after all, with plenty of scientific jargon about brain waves and neurons and whatnot. Still, I enjoyed learning about the different kinds of sleep, (REM, NREM) and the different functions they serve. It’s magical to me that we can literally view what’s occurring in the brain during these different kinds of sleep. If you have struggled with sleep issues or simply wondered about why we even sleep, this book is a must read for you!


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