Why We Sleep Book Summary

Book Summary

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Brief Summary

Every animal on Earth sleeps. Humans go even further, using sleep for inspirational dreams, emotional processing, and memory development. Since humans discovered fire, sleep has played a unique role for our species.

Without enough sleep, you may struggle with high blood pressure, weight gain, diabetes, Alzheimer’s, and cardiovascular issues in the long-term. You may also feel foggy or emotional in the short-term.

Your body may compensate for sleep deprivation with microsleeps. By sleeping in a tiny increment, your body goes through the motion of sleep. This can put you in a dangerous position if you’re doing something like driving. It can also put you in an embarrassing position if it happens during a meeting.

If you want to prioritize sleep, be careful about what you put in your body. Ease up on caffeine and don’t rely on alcohol to get sleepy. Try to quit that nicotine habit and get lots of natural sunlight during the day. Your body’s internal clock wants you to get enough rest, so it’s better to just go with the flow.

About the Author

Matthew Walker calls himself the “Sleep Diplomat.” He has built a career on studying the science of sleep and its impacts.

Walker was born in the United Kingdom. He studied neuroscience at the University of Nottingham and got his Ph.D. in neurophysiology from Newcastle University.

While working as a professor of psychiatry at Harvard Medical School, Walker studied the effects of sleep on performance. He then moved to a role at the University of California, Berkeley. There, he created the Center for Human Sleep Science to further research sleep.

Walker has also worked with technology companies. With the life sciences division of Google, he helped to develop a sleep diary. Walker also worked with Hello on a sleep tracking device until the company ceased operations in 2017.

Why We Sleep is Walker’s first book.

Topics

Psychology Health & Nutrition

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Key Insights

We sleep because we need it to survive. Sleep is the time that we rest, regroup, and re-energize ourselves. Getting enough sleep is critical for your physical and mental health.

Sleep is important for your mental functions. Your brain uses the time to process emotional experiences and organize your memories. If you don’t sleep enough, you’ll feel the cognitive impairment.

More than just slowing down, sleep is a matter of life and death. Chronic sleep deprivation is linked to a variety of serious health issues. Also, in a state of sleep deprivation, you’re like a drunk. So you could pose a danger to others, especially behind the wheel of a car.

Sleep is something all animals do in some form. For humans, the unique aspect is the amount of time spent dreaming. Dreams hold ideas and problem-solving that can be inspirational if you’re able to identify them.

But first, you need to sleep enough to harness the full power of your slumber.

Your circadian rhythm is your body’s internal clock.

Are you a morning person or a night owl? Maybe you like to stay up late and get your best work done in the middle of the night. These preferences are determined by your circadian rhythm.

The circadian rhythm is like a clock inside your body. During every 24-hour period, there are times where you feel the need to sleep or times when you feel more awake. Your circadian rhythm also gives you other biological cues, like being hungry or thirsty. Some fluctuations in your mood can also be linked to your circadian rhythm.

If you weren’t waking up to an alarm clock or dictating your day based on a work schedule, your circadian rhythm would drive when you do your daily activities. Each person’s body clock is a little different. But you can get a sense of it based on when you naturally feel sleepy or when you wake up when you haven’t set an alarm.

If you’re a night owl, your morning meetings are probably harder. Most people do better during the day, but 30 percent of people are closer to nocturnal. For these folks, morning and afternoon are when they’re in their sleepier phases. It’s harder for them to get enough sleep.

You dream and maybe even sleepwalk during your REM phase of sleep.

Sleep has three phases: light, deep, and REM. Rapid-eye-movement (REM) sleep is named for the way that your eyes move from side-to-side under your eyelids while you’re in the REM phase of sleep. Light and deep sleep are both non-REM sleep.

You go through the phases of sleep in cycles. Starting with light, then deep, then REM. Then, you start the cycle over. The amount of time spent in each phase varies by cycle. The earlier cycles will have more time in deep sleep and the later cycles will have more time in REM.

Each phase has a purpose and your brain activity is different in each phase. Think of your brain as a computer. When you start sleeping, you’re disconnecting your computer from inputs...