Why we sleep by Mathew Walker: detailed review chapter 1 to 5

 Mathew Walker: Why We Sleep

(summary chapter 1 to 5 explained)

Why We Sleep Part 1 Chapters 1 to 5

Overview:

Professor Matthew Walker, Director of UC Berkeley's Sleep and Neuroimaging Lab, studied twenty years of research to explain why sleep matters. 

This book has 4 parts and 16 chapters in total. In this post I will be discussing part 1 and the rest of the parts will be discussed in upcoming posts. I am writing a detailed review as the author wants to make our concept clear about life, health, and longevity by highlighting the following points:

• the consequences of sleep deprivation, 
• effects of caffeine and alcohol on our sleep, 
• reasons for changes in sleep patterns throughout our life. 

Table of Content Why We Sleep

Summary Chapters 1-5 Why We Sleep

Chapter 1 Why We Sleep

Our society shows an indifferent attitude towards sleeping as science has failed to explain its importance, to begin with. From a biological point of view, sleeping doesn’t make sense: during sleep hours, we can’t have food, interact with each other, reproduce, or protect our kids, and above all, we are vulnerable to predators. But all known species of animal kingdom sleep. 

Chapter 2 Why We Sleep

In Chapter 2 author discussed two factors determining our alertness or tiredness:

1. Circadian rhythm
2. Sleep pressure

The discussion includes the effect of caffeine, jet lag, and melatonin on these factors.

chapter 2 Why We Sleep

 Apart from determining your level of alertness or tiredness, the Circadian rhythm also controls your preferences for food or drinks, your emotions, and the release of additional hormones.

The brain uses multiple factors to reset the internal biological clock the most important being daylight. Other external factors include food, exercise, temperature changes, and social interaction.

Chapter 2  Why We Sleep

      Although human beings have a twenty-four-hour pattern, the peak of wakefulness varies as a result people are referred to as (morning types) "the morning larks" or (evening types)“night owls”. Remember! belonging to one group or another is entirely biological and this isn’t a choice. These types are natural ways of avoiding susceptibility. If we were sleeping together as a large group, it makes sense that some members go to bed at 9 PM and get up at 5 AM while others go to bed at 2 AM and get up at 9 AM.

Chapter 2 Why We Sleep

Adenosine (a chemical) builds up in the brain, the more time you’re up, and peaks twelve to sixteen hours after waking up. Adenosine can be neutralized with caffeine. Although caffeine's effect peaks half an hour after taking it, it stays in your system for hours. There are many sources of caffeine such as coffee, some teas, dark chocolate, and energy drink. Moreover, the older we get, the longer it takes for caffeine to leave our system.

Two important questions to be asked: 

 1) Can you fall asleep at 10 AM if you desired to?

 2) Without caffeine before noon, do you feel fine?

 If the answer is a big  “no” to these questions, then probably suffer from sleep deprivation. Over time if you are not getting enough sleep, adenosine levels concentrate and accumulate and it keeps returning in the form of fatigue.

Chapter 3

Chapter number 4 Overview: Ape Beds, Dinosaurs, and Napping with Half a Brain

In this chapter author basically tells about the basic sleep differences from specie to species. These facts seem interesting.

•  Some animals have longer sleep times than others.
• Some species do not have Rapid Eye Movement (REM) Phase meaning no dreams.
• There is a Diversity in the way in which species in the animal kingdom sleep. Some sleep with half their brain as a life-preserving mechanism, for instance.  Meaning, as they sleep,  half of the brain sleeps and the other half is in charge of the movement.
• Some basic bodily functions affect sleep patterns too. If you’re starving, for example, you’ll stay awake longer.

The author then explains a monophasic pattern of sleep (a long bout that takes around eight hours), followed by humans in developed nations. A biphasic pattern (around eight hours followed by a thirty- to sixty-minute nap in the afternoon) is better to adapt.  An afternoon nap lowers the chances of heart disease.

Chapter 5 Why We Sleep

Talking about older adults, in Chapter 5: irrespective of what some people believe, also need sleep, perhaps as much as younger adults. As we age there is an alteration in sleep due to several reasons though, some are as under;

•  Fragmentation:  wakes up more often because our bladder weakens.  
• Regression in the circadian rhythm as we age, causes us to go to bed earlier and earlier. If older adults try to stay awake for longer periods of time than usual, they might take an accidental nap and this affects their sleep.
• Finally, due to deterioration in the regions of the brain that generate deep sleep older people lose deep sleep in both quality and quantity. 

So this is all about the first five chapters. For further chapters please check out my upcoming posts.