I have always been fascinated by sleep. I have had my parents advice me to sleep well before every exam - but obviously I never did. I took up this book to understand why people usually stress a lot on good sleep. And 15 pages into this book, I kept this book aside and slept because it was already thirty minutes past my bed time. And ironically even the author suggests the reader to sleep.

Should you feel drowsy and fall asleep while reading the book, unlike most authors, I will not be disheartened. Indeed, based on the topic and content of this book, I am actively going to encourage that kind of behaviour from you

Detailed Highlights and Notes

Using Kindle has made sharing highlights and notes pretty easy. I have my personal highlights, however when I was deciding whether I should read this book, I came across this detailed notes from this book which would serve its purpose well - Poor Ash’s Almanack

Things I knew about sleep before I read this book

  1. We all have heard this - “Sleep is very important”. It helps our brain and body get the much deserved rest.
  2. Sleep also helps in recovering emotionally.
  3. There are two different stages of sleep - REM and NREM. Although I never exactly understood the difference.
  4. Dreams are very often related to our daily emotional state - if we are depressed, our dreams will reflect that.

Which opinions were created/changed after reading the book?

  1. There is a very complex scientific process that the body undergoes to keep in track sleep and the biological cycle at large. There are two major hormones that help the body - melatonin (helps regulate biological timing) and adenosine (acts like sleep pressure).
  2. Caffeine masks the very effect adenosine and hence tricks the body to be active, in spite of it needing the sleep. One very alarming fact about caffeine is the very long half-life. A 2PM cup of coffee will still has a certain residual affect at 11PM at night.
  3. I have personally woken up exactly two minutes before my alarm whenever I had a big day. It was fascinating to know that this happens to everyone.While our conscious mapping of time is lost during sleep, at a non-conscious level, time continues to be cataloged by the brain with incredible precision.
  4. Time is usually elongated in dreams. Whenever I fall asleep between two alarms, it feels like I lived a whole day within a dream in spite of having a mere 10 minute difference between the alarms.
  5. Night owls and early risers are not who they are by choice. It is not their conscious decision, rather their genetic fate. Interestingly if you think about it, the cultural norm are very biased towards early risers. Even personally, I have tried to create a habit of waking up early quite many times.
  6. It is usually very hard to acclimate to a new time zone when travelling eastward than when flying westward. The major reason - eastward direction requires that you fall asleep earlier than you would normally, which is a tall biological order for the mind to simply will into action. While the westward direction requires you to stay up later, which is consciously and practically an easier option. Now I know why it is tough to beat jet-lag when travelling back home to India from the US!
  7. REM or Rapid Eye Movement Sleep is when the brain is as active as when we are awake. REM is where we dream. The brain paralyses our body during REM cycle so that the brain can dream safely.
  8. NREM is where the brain eases off into a slow-wave sleep which triggers a state of inward reflection—one that fosters information transfer and the distillation of memories. Think of this as slow AM waves - they have a longer range. These long-range brainwaves of NREM will move memory packets (recent experiences) from a short-term storage site, which is fragile, to a more permanent, and thus safer, long-term storage location.
  9. Humans will have a very different circadian cycle at different ages in their life. Inside a mother’s womb, the sleep in majorly dominated by REM since it establishes a neuro architecture - a framework that will engender thoughts, memories, feelings, decisions and actions. Toddlers ought to have a polyphasic sleep because the part of the brain that controls the circadian cycle takes time to develop. For adolescent teenagers, the cycle moves a bit forward and hence most teenagers want to stay up till late. These biological facts are something we as humans should know - somethings are just beyond our control!
  10. An average human has a stable balance of 80/20 NREM-to-REM ratio. Things are very different for infants wherein the ratio is almost 50/50. The author beautifully expresses this as an act of modelling and remodelling. REM in infants act like a creator - someone who establishes neural highways. While NREM in later part(particularly childhood) helps in maintaining and remodelling according to experiences. If we think about it, this is the reason why childhood plays such an important role in moulding a human brain.
  11. I never knew that sleep and memory are intensively linked. Sleep before learning moves old stuff out to an external hard drive, creating room for the new; sleep after learning makes sure that stuff gets stored instead of lost. There are scientific methods like - sleep stimulation by audio waves to improve NREM sleep and targeted memory reactivation that researchers are experimenting with.
  12. While NREM is majorly associated with learning, REM is the phase that helps in emotional stability through dreaming. REM-sleep dreaming offers a form of overnight therapy. That is, REM-sleep dreaming takes the painful sting out of difficult, even traumatic, emotional episodes you have experienced during the day, offering emotional resolution when you awake the next morning.
  13. REM dreaming also fosters problem solving and creativity. In this phase, the brain is no longer constrained to see the most obvious connections. It becomes very actively biased towards seeking out the most distant, non-obvious links between two sets of information. Maybe this is why most of our dreams constitutes random un-related experiences from our brain.

How can I use the lessons learnt from this book in my real life?

  1. Since caffeine remains in the body for at least 5-6 hours, I decided not to consume coffee after 4PM.
  2. Sleep deprived driving is more dangerous than drunk driving. And this fact has made me more careful whenever I or someone I know travels at night!
  3. And to sum the whole book - I have grown more conscious about how important sleep is. And I would start investing in making my sleep better.

Any links with previous books I have read?

  1. It is fascinating to learn about how life evolved on Earth. Homo Sapiens have walked through a great journey of evolution to reach the current version of us. The author hinted of how sleep could have been our primary phase of life and slowly we evolved into being awake more.
  2. Yuval Harari in Sapiens explained how the brain size got bigger once we started walking on two legs and how the fact that we can create myths evolved us into the most dominant species on Earth. This books seconds that idea and relates how REM sleep helped in making emotional and cognitive connection between thoughts. This book will definitely rank up top with Sapiens in terms of knowledge I gained!