Why We Sleep: Unlocking the Power of Sleep and Dreams by Matthew Walker

Summary
  1. An incredible in depth look at sleep, the research behind it, and its vast array of benefits – mentally, emotionally, physically
Key Takeaways
  1. 12 Healthy sleep habits tips
    1. Keep a consistent sleep schedule – setting an alarm an hour before bedtime to know when to start winding down is often helpful
      1. A consistent bed time and wake time is really important. You would think that if you normally sleep 8 hours and cut off 2 hours in the morning, that you’re losing 25%, right? Nope – because of sleep cycles and their timing, you could be losing around 60-90% of vital REM sleep
    2. Get 30 minutes of exercise per day but not 2-3 hours before bed
    3. Avoid big dinners and drinking too many liquids before sleep
    4. Avoid alcohol before sleep
    5. Avoid caffeine and nicotine
    6. Avoid medicines which delay or disrupt your sleep
    7. Relax for at least 30 minutes without too many lights or stimulation for at least a half hour before bed
    8. Take a hot bath before bed as this helps your core body temperature drop letting you fall sleep faster and get deeper sleep
    9. Don’t take naps after 3 PM
      1. A long night sleep with a 30 to 60 minute nap in the afternoon seems to be the ideal scenario that our ancestors formed and that we should try to follow if possible
    10. Have a dark, cold (between 65 and 68°F) and technology free bedroom
    11. Get enough sunlight at the right times – try to get at least half an hour out of direct sunlight a day and emphasize it in the morning and try to avoid it as much as possible in the evenings with sunglasses and by staying inside
    12. Don’t lie in bed awake – if you’re having trouble falling asleep or feel anxious get out of bed and do something relaxing but don’t just lie there
  2. 2/3 of adults don’t get enough sleep and this has horrible physical, mental and emotional health detriments.  It is one of the four core human drives along with needing to eat, drink, and reproduce and it is found across the entire animal kingdom. Although this would lead us to believe it is extremely important, sleep has been neglected for a long time and most people put it off and take the point of view that they’ll sleep when they’re dead and this will only get them there that much quicker
  3. There appears to be no major organ or physical or emotional function which does not benefit from deep sleep and which does not get harmed by lack of sleep. It helps with memory, learning, making rational decisions, being emotionally stable, helping us maintain weight, boosting our immune system, consolidating memories, giving the brain a “virtual reality” space to play out ideas and memories and put them into long-term storage. Sleep helps consolidate memories and put them into long-term storage but by also thinking about which memories you want to save before you go to bed you could increase their clarity even further
  4. Melatonin is the night time hormone which gets released to tell the body to start preparing for sleep. Sleep pressure is caused by adenosine and it is the second portion of why we get sleepy but caffeine and other stimulants block it which is why they help us feel more awake
  5. The suprachiasmatic nucleus controls the circadian rhythms of our bodies which in turn controls hormones, appetite, when we want to sleep, body temperature and much more
  6. It is a genetic predisposition and not a choice whether we are morning or late night people
  7. 3 easy questions to determine if you’re sleep deprived: Do you wake up without an alarm? Could you fall asleep by 11am? Could you function at a high level without caffeine?
  8. Caffeine has a longer half life than most people realize: a cup at lunch could still be affecting you by bedtime so that you don’t get as deep of a sleep as you otherwise would
  9. Sleep is Mother Nature’s best attempt at contra-death
  10. There is no replacement for proper sleep – not caffeine, not willpower, not brief naps, nothing
  11. Sleep is a unifying feature of the animal kingdom found across all birds and mammals although the time and specifics change quite dramatically
  12. The author argues that REM sleep is one of the most important things that has shaped us evolutionarily and helps us with our complex socio-cultural and emotional signals that we have to deal with as being part of a complex society.  And, equally as important, REM sleep seems to help with creativity and these two factors help to humans get on top of the world hierarchy extremely quickly
  13. Sleep not only helps consolidate memories but also helps incorporate skills such as music, sports, movement, and other things. Pianists often find that after practicing for a day that they can wake up the next morning play the new tune perfectly
  14. 10 consecutive days of seven hours of sleep impairs you as much as going a full day without sleep
  15. The brain cannot accurately assess how sleep deprived it is when it is sleep deprived
  16. REM sleep and dreaming are necessary for emotional healing to take place after difficult or traumatic events
  17. When lacking sleep, we revert to a more primordial reactive state where we don’t consider the broad picture, the true context, or the people we are dealing with and it is partially responsible for when you just “snap”
  18. Lack of dreaming distorts your ability to recognize faces and facial patterns confusing friendly gestures for menacing ones and making you more jumpy and aggressive
  19. Dreaming helps you problem solve and become more creative and some people have tried to control this aspect through lucid dreaming to help them in their work, lives, or business (and sometimes successfully so!).
  20. It is sleep and dreaming which helps you connect disparately connected facts, it is the difference between knowledge and wisdom
  21. Snooze buttons are terrible for our health as they jolt us out of sleep not once like an alarm does but several different times
  22. Teenagers’ circadian rhythm‘s are shifted later in the day and there has been great success with schools who experimented with later start times. Teenagers starting at 8 AM would be similar to most adults having to get up and get ready at around 3 AM. There are many pragmatic reasons why this is difficult to do but the it has shown that by shifting start times later there is a 70% reduction in teen traffic mortality rates.
  23. Another side-effect of lacking sleep may be ADHD. Young kids who are sleep deprived show many similar symptoms which are associated with ADHD and may be part of the reason why this diagnosis has become so much more common in modern times. Many students aren’t actually hyper active but merely lacking sleep
  24. For businesses he recommends setting up some sort of incentive system to get people to sleep more. He recommends using a sleep credit system where total hours of sleep and sleep continuity are measured in the rewards are either financial or extra time off and vacations
What I got out of it
  1. Incredible data backing up and reinforcing how important sleep is. The 12 sleep tips alone made this worthwhile