Why we sleep? (Book Review)

Unlocking the Power of Sleep and Dreams

This book by Matthew Walker, offers a easy and readable and a bit spooky survey of modern sleep research. Awesome reading material, for someone whom at time lack sleep.

As per one of my favorite quote from House of Cards by Francis Underwood,

“I’ve always loathed the necessity of sleep. Like death, it puts even the most powerful men on their backs.”

So here’s what I learned from the book.

  • Sleep facilitates memory, creativity, problem solving and the acquisition of motor skills.
  • It recharges the immune system, modulates blood sugar, clear coronary arteries and wards off disease.
  • Most adults nowadays fall short of the recommended amount of sleep
  • Modern life including its lights, air travel, caffeine, alcohol and workday has adversely affect out sleep. Side effect of our modern lifestyle include impaired memory, decreased productivity and drowsiness.

The 10 Main lessons and insight from the books

1. Sleep is a true panacea

In case you’re wondering, panacea means a solution or remedy for all difficulties or diseases.

So, a full night of high quality sleep refreshes the immune system, moderates appetite and supports the digestive system. (I wonder if it could helps with my diet)

Walker suggest that when you sleep well, you increase your ability to learn, to retain memories and make decisions.

He asserts that the right amount of sleep nourishes emotional balance and creativity.

I used to sleep in early before exams, I found it as much better than last minute all night cramming.

2. Sleep deprivation is very dangerous

The book showcase latest research which makes it clear that sleep deprivation (lack of sleep) will cause your heartbeat to accelerate, increases your blood pressure and degrades the health of your coronary arteries.

Walker details how lack of sleep will compromise our immune system, especially causing the loss of vital cancer-fighting “natural killer cells’. Even minimal amounts of sleep deprivation wreak havoc with your ability to focus and concentrate.

In addition, such inattention can become life-threatening when it affects drivers, health care professional or any safety critical personnel. In my line of works, I believe you would need enough sleep / rest since nobody can work for more than 12 hours straight.

Walker also cites sleep loss as a factor in the obesity epidemic. Might be the actual reason why I gained quite a lot of weight this few years. Lucky that I’m not yet obese. The reason is that sleep moderates our appetite and people with little sleep tend to crave and eat more. They are also more likely to want to consume sweets, high-carbohydrate foods and salty treats. Plus, if you’re not sleeping, you might be hungry in the middle of the night, and it most definitely not going to help with your diets.

Walker also touch on the role of sleep deprivation in enhancing every psychiatric malady including the likes of depression, anxiety and bipolar disorder.

*in case you’re wondering what malady means, it means a ‘disease or ailment’.

3. The circadian rhythm gives your brain the signals

Our body has 2 processes for telling us when to sleep.

  1. Our internal clock, the circadian rhythm, which tells the brain whether it’s day or night.
  2. Walker identifies the 2nd mechanism as “sleep pressure”. It involves a hormone called adenosine, which is build up in our brain throughout the day. Therefore, when it reaches a certain level, it makes us drowsy and want to sleep, or induce sleepiness.

Okay, some additional information on the circadian rhythm,

  • Our brain follows the circadian rhythm to regulate our body processes and chemicals.
  • It supports wakefulness in the morning and drowsiness at night. (I wonder why it most of the time doesn’t work for babies?)
  • Daytime alertness increases throughout the morning and reaches a peak in the early afternoon.
  • When the sun goes down, our brain begins to make the transition to sleepiness by releasing the hormone melatonin.
  • Walker points out that contrary to popular belief, melatonin doesn’t, on its own, induce sleep.
  • Instead, it acts as a signal that tells the brain when its night and when the brain should initiate the process that generate sleep.

4. Two major phases of sleep offer different benefits

  1. REM Phase: Rapid-eye-movement sleep is also called ‘dream sleep’.
    • During this phase, our eyes shift quickly from side to side.
    • Produces brain-wave activity that quite like that of the brain when we are awake.
  2. NREM: All other phases other than REM. Literally means Non-rem sleep.
    • the brain produces steady rhythmic waves that differ from both the REM phase and the waking brain.

5. Most people don’t get enough sleep

  • 2/3 of the adults in developed nations fall short of achieving at least 7-9 hours of sleep a night.
  • Countries with the largest declines in sleep times such as USA, UK, Japan and South Korea have also have experienced the largest increase in diseases such as cardiovascular disease, cancer, Alzheimer’s disease and depression.
  • World Health Organization (WHO) describes sleep loss as epidemic in the industrialized world.

6. Blame modern life

  • Many of the technological advances that have made our life more convenient also produce the side effect of undermining natural sleep.
  • One of the most potent obstacles to healthful, sound sleep is artificial light which upsets the body’s natural responses to daylight and darkness. (Artificial light, as opposed to natural light, refers to any light source that is produced by electrical means.)
  • Introduction of new light bulbs that incorporate light-emitting diodes (LEDs) have made this situation very much worse.
  • These LEDs found in laptop screens, smartphones and tablets which emits a short wavelength blue light that’s twice as potent as incandescent light in damping down the body’s release of melatonin.
  • Jet travel also plays havoc with your circadian rhythm, notably when you arrive in a new time zone. Your body continues to follow the circadian clock it set in your previous time zone
  • Citation on some studies that found that frequent time-zone hoppers, such as airline crew members, suffer weakened short-term memory and higher rates of cancer and Type 2 diabetes than the general population.

7. Caffeine and alcohol degrade sleep

  • Caffeine interferes with sleep inducing signals in our brains.
  • Caffeine tricks our body into thinking it’s not drowsy, and it remains in your system for a long time, up to 6 hours or so after each cup.
  • Alcohol sedates the brain, drink enough and you will easily drift into a state of unconsciousness.
  • Unfortunately, alcohol induced state of mind isn’t natural sleep.
  • Alcohol-induced sleep isn’t continuous, it causes repeated awakenings to puncture your night’s sleep.
  • Alcohol also suppresses REM sleep.

8. Sleep plays a major role in memory

  • A good night’s sleep preserves new memories from your day and integrates them with your existing store of knowledge.
  • Sleep prepares your brain for acquiring new memories
  • When you learn new things, the brain process it as a short-term memory in its hippocampi, which have limited capacity.
  • During NREM sleep, the brain moves the memories from the hippocampus to the greater-capacity cortex for long-term storage.
  • The process as analogous to transferring data from a memory stick to a computer’s hard drive.
  • The brain is capable of greater discernment about data than the best computer
  • During NREM sleep, the brain decides which information is worth preserving and which it can throw away

9. Sleeping pills aren’t the best solution to sleeplessness.

  • They don’t produce a natural sleep
  • Pills produce a sedative effect similar to that of alcohol.
  • Pills have unpleasant side effects which shows up next day as sluggishness, forgetfulness and slow reaction time. Similar to that of alcohol?
  • Walker prefer a new non-drug sleep therapies, such as “cognitive behavioral therapy for insomnia” (CBT-I).
  • Over several weeks, the patient and a therapist work on a program to address bad sleep habits and the underlying anxieties that may deter sleep.

10. Practice good ‘sleep hygiene’

  • First and most effective step is to stick to a schedule of sleeping and waking times
  • Keep your body temperature low at night by turning down the bedroom thermostat and avoiding exercise near bedtime.
  • Refrain from caffeine and alcohol, and avoid heavy meals at night.
  • Dim artificial lights in the evening and turn off LED screens.
  • If you can’t get to sleep after 20-minutes, get up and engage in a relaxing activity rather than tossing and turning in bed.

Additional Related Titles on Sleep

  1. Why we sleep?
  2. Between work & sleep
  3. Move – Eat – Sleep – Think – Individual Right!
  4. Morning Routine to Unlock Unrivaled Work Performance

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