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Heart & Soul of Why We Sleep by Matthew Walker

Hey Reader, Parul here and today I have for you one of the eye-opening reads! I recently read the book “Why Do We Sleep” by Matthew Walker. If you are like me, then sleep seems to be most un-productive thing we do. Isn’t it? I mean, we spend a third of our lives motionless when we could be getting stuff done. Now when I realised, what the brain was doing while we were sleeping, I think sleep happens to be the most productive thing we do all day.

Author Matthew Walker is a professor of neuroscience at UC Berkeley and he also is a sleep scientist at Google. He fully admits at the beginning of the book that when he set out to research sleep, he thought it would only take him a couple of years to find the answers to his research question. But, in reality, it took 20 years’ worth of research, and now he has been able to produce this book. Sleep though ubiquitous across just about every species albeit in different forms is a phenomenon that has historically not been well understood. I mean just think about it, we have concrete explanations and reasoning behind all of our other biological processes. However, scientists have not been able to come up with a perfect explanation for precisely why we sleep. Isn’t that intriguing? I remember in some book that I read the only explanation that a very knowledgeable scientist could come up with for “Why We Sleep” is that we get really sleepy! On the most, basic level sleep seems like a bad idea for our species or any species. We go into a state of paralysis where we are unable to gather food, socialize, nurture our young or protect ourselves from predators. Indeed, we are infinitely vulnerable to danger. (Sorry! Too much of Game of Thrones)

But truly, have you ever wondered if the act of sleeping can put an organism in peril why does every species do it in some capacity? It must have some serious value or else evolution would have weeded out all of our years ago. By the virtue of this book, we are only starting to understand the necessity and benefit of sleep and this book is a deep dive into the realm of sleep research.

Heart of the Book

This book is divided into four different parts. First part is all about the physicality of sleep and sleep rhythms. The second part discusses the health impacts of sleep. Third part is all about dreams and the last part of the book is a look at our modern attitude towards sleep. What I loved about the book is that while each section is equally compelling but as they don’t compound off of each can be read separately from all the others. Therefore, good for Anaisha, as her mumma can pick up right where she left off! What I found persistent across all the parts/sections is the urgency in Walker’s tone about the importance of sleep.

Haven’t we all heard from doctors just about as soon as we can understand words that diet and exercise are the keys to healthful living? Yet Walker argues that sleep trumps both of them and furthermore he argues that sleep is the keystone upon which the other two rest. Sleep is like a hearty dose of an all-care medicine that each of us takes every single day. It is absolutely fantastic for your brain! While you sleep your brain is consolidating information it’s locking in memories while getting rid of useless ones making room for new things in your brain. Your brain is still processing information while you doze. That’s the reason why it is difficult to understand or work on something very complicated at the end of the day. However, it can just click after you wake up! I remember my mom reminding me about the old adage while I am discussing this book with her “I sleep on it and let you know how I found the book”. It is a really good suggestion but sleep doesn’t just make for a healthy mind but also a healthy body. It can lower your appetite to a healthy level. It can help protect you against a slew of health problems like cancer, stroke, heart attack, diabetes, and dementia. Walker correctly emphasizes in this book that if there were a pill to give us all of the health benefits that sleep already gives us then that product would have the best profit margins of anything on the market. So the eternal question must have popped into your head, if we all have access to the miracle drug of sleep why are we all still not getting enough of it? Unfortunately, the biggest culprit in our modern world is our work and sense to complete it all before we sleep. Our indulgence and the grind till you die work ethic fetish insists that giving up sleep in order to be more productive. But the studies in this book show that we are doing so at the expense of our well-being! It’s getting to the point where doctors are prescribing sleep to patients, a mid-day nap which is common in some European countries.

In many ways, we as a society have chosen to ignore our own biology. We try to pretend that our bodies don’t need seven or nine hours of continuous sleep every single night. The studies in this book show that if you even get one hour less than what your body needs it will have deleterious effects on your health. Moreover, there are more residual side effects to our modern age that are literally keeping us up at night.

Soul of the Book

Author and doctor Matthew Walker have studied sleep for over two decades and he has found that during a full night of sleep our brain transition between three types of sleep – Deep Sleep, Light Sleep, and REM Sleep also known as Dream Sleep. Every 90 minutes we cycle through these three phases of sleep. However, not every sleep cycle is the same!

When we fall asleep the first 90 minutes of sleep is mostly Deep Sleep. When you stay up a bit later than normal to watch a movie or browse the internet you are scarifying a large portion of your Deep Sleep that night and that’s something you might regret later. Well let me explain to you with an analogy, think of Deep Sleep like a mail delivery service. During the day your mail room collects packages, this mail room is your hippocampus a temporary storage space in your brain. The packages are bits of information you have learned during the day like a person’s name or the steps of a new work procedure. So, when you fall into a deep sleep you start up the fleet of delivery trucks and start delivering packages from your mail room to the permanent addresses in your brain outside of the hippocampus. However, if you decide to stay up late and skip out on the first two hours of your regular sleep schedule you will fail to get those packages to their intended destination and the contents of those packages might be lost forever. Author Matthew Walker says that right after Deep Sleep is a period of Light Sleep. Light Sleep is like mail room cleaning staff its job is to clear the hippocampus every day because after being awake for 16 hrs it is hard for your hippocampus to hold on to any new information. That’s why if like me you also are staying up late to read a book, you often find yourself reading the same paragraph over and over again! Lol! This is because we failed to comprehend the information and now, we know the logical explanation for it. Light Sleep is a mental refresh that renews your ability to learn new facts. In order to prove this author Matthew Walker invited two groups of students into his lab.

· Group 1– This group of students just pulled an all-nighter

· Group 2 – This group of students got a full night of sleep

Around noon he had them study the same set of facts then allowed them to get two full nights of sleep he tested how many facts they could recall. The group that was sleep-deprived, those students who failed to get enough light sleep and clear out their hippocampus the night before learning were able to recall only 40% fewer facts. That’s the difference between an A and F. Majority of our Light Sleep is at the end of our regular sleep schedules which means waking up early to study is actually counterproductive. Waking up early and only getting 5 to 6 hours of sleep severely impairs our ability to learn new information and if you get up much earlier than normal say 4 AM instead of the usual 6 or 7 AM then you are also missing out on the majority of your REM sleep.

As interesting as it sounds, REM stands for Rapid Eye Movement. Author Mathew Walker says that if you were to film yourself during REM sleep you would see your eyeballs rapidly moving underneath your eyelids. Indeed, we pretty much look like we are possessed. However, if you filmed the rest of your body you would see nothing because during REM sleep the rest of your body is completely paralysed. In order to illustrate what happens in your brain during REM sleep let us use another analogy. My husband keeps on telling me about Cloud and teaching me few programming of the cloud so let me relate this analogy with that. If Deep Sleep is like a program that stores handwritten notes that you made during the day into a permanent cloud-based note-taking system like Ever-note. Then REM is like a program that goes through those notes in the cloud combines them edit them and produces a story you can understand. Therefore, when we enter REM sleep our mind gets into work trying to make sense of what happened during the day. To do that it makes connections between newly stored information and previously stored information. The connections it makes are often bizarre and something you would never think to do while you are awake. However, the result is often a creative breakthrough for writers this means waking up with an outline to their next chapter in mind. For entrepreneurs it means waking up with new product strategy for scientist this means waking up with a perfect experiment in mind and for musician it means waking up with the perfect melody in mind. 

In fact, singer and songwriter Paul McCartney famously woke up with the entire melody of “Yesterday” in his mind and thought someone else had written the song. Essentially, REM sleep not only offers creative insights, it also offers emotional insights! Walker explains that the dreams we experienced during REM sleep act as a form of therapy. In the book he says, think back to your childhood and try to recall some of the strongest memories you have. what you will notice is that almost all of them will be memories of an emotional nature perhaps a particularly frightening experience of being separate your parents or almost being hit by a car on the street also notice however that your recall of those detailed memories is no longer accompanied by the same degree of emotion that was present at the time of the experience. You have not forgotten the memory but you have cast off the emotional charge or at least a significant amount of it. y\You see without dreams we would all suffer from chronic PTSD. Dreams thrust us back into anxious moments so that we can move past that anxiety and move on with her lives. If you are going through a bitter breakup or divorce it cycles REM sleep so that we can transition from despair to hope. If deep sleep improves our ability to recall information and light sleep improves our ability to learn new information then REM sleep improves our ability to make sense of that information and any emotions connected to that information. But if we fail to get a full night’s sleep a full seven to nine hours of sleep and miss any part our Deep, Light or REM sleep we will remember less, learn less and understand far less. Without a full night sleep, it is impossible to be our best selves! So, ensure that we get a full 7 to 9 hours of sleep each night. Truly, sleep needs to be our number 1 priority during the day that’s why every day, I have sleep scheduled in my calendar and I treat it like the most important meeting of the day to be ready for that meeting and fall into a deep sleep at the same time every day. 

With all the work and nurturing of an infant, sleep deprivation was dawning to me. Thanks to this book and my parents I am trying to build night habits based on 2 pillars of good sleep hygiene dark and cool. It is working for Anaisha and her dad, Mr A. Actually, when our brain detects light especially the blue spectrum in light it suppresses the release of melatonin and that’s not good. This is because melatonin triggers your first sleep cycle and provides the initial push you need to fall into a deep sleep. You know, how are parents joke about close the light and kids sleep, well let me tell you that’s true. Of course, you still need to rock and sing along to the kid for sometime but eventually they do fall asleep.

I personally have had some issues with my sleep over the past couple of years, especially after Anaisha. I am someone who needs to keep a really stretched sleep schedule or else my circadian clock gets pissed off at me. Now, I am trying to revamp my sleep schedule as well as my family. I stopped using devices an hour before bedtime. After reading this book I am now treating sleep with the reverence that it deserves. Anyone who thinks that way should absolutely read this book. Those are my thoughts on this fantastic non-fiction. that I would definitely recommend it!



Walker, M. (2017). Why we sleep: unlocking the power of sleep and dreams. New York, NY : Scribner, an imprint of Simon & Schuster, Inc.

Hope you Enjoyed & Lemme know your Feedback! Connect with me in case you are interested in the Book….Cheers!


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Stronger Together!

Hey there, I'm Parul, working in one of the Big 4s of consulting! 💼

By day, I'm decoding the business matrix, but by night, I transform into a book ninja, stealthily navigating the worlds crafted by the greatest authors📚✨


What's the secret sauce to my consulting wizardry, you ask? It's the lessons learned from the pages of both leadership meetings, strategies and bestselling novels 😉


I'm not just crunching numbers; I'm crunching captivating narratives 💖

Buckle up for insights that transcend industries and a blog where business acumen meets the magic of storytelling


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