Dan Ciotu's Key Ideas from Why We Sleep: Unlocking the Power of Sleep and Dreams
by Matthew Walker

Each cycle lasts around 90 minutes with different NREM / REM ratios:

• Cycle 1: NREM (80%) -> REM (20%)
• Cycle 2: NREM (70%) -> REM (30%)
• Cycle 3: NREM (60%) -> REM (40%)
• Cycle 4: NREM (50%) -> REM (50%)
• Cycle 5: NREM (40%) -> REM (60%)

1. During REM sleep our body gets paralyzed by the brain in order to prevent us from executing on our dreams.
2. Sleeping helps us improve. When we’re learning or practicing something and we stop, our brain will continue to work on these tasks on the background. This passive learning process gets even stronger when we shut our eyes.
3. Sleep fuels our creativity. During sleep our brains build connections, nurturing our problem-solving skills and imagination.
4. The main function of dreaming is to help us resolve past, or current, emotional problems.

1. Consuming alcohol to persuade yourself to sleep is a bad practice. Alcoholic beverages mess up your REM sleep and you get a fragmented sleep.
2. With age, our sleep efficiency declines. This is mainly because of our frequent visits to the bathroom. A simple fix will be to reduce the intake of fluids before going to sleep.
3. A lack of sleep can lead to a lot of nasty outcomes: diabetes, depression, chronic pain, stroke, cardiovascular disease, and Alzheimer’s disease.
4. You can’t sleep it off: Even if you get enough sleep to recover from last night’s party, the sleep deprivation will never heal.

1. Stick to a sleep schedule. Create a sleeping habit by going to bed and waking up at the same time, every-single-day.
2. Exercise, but don’t do it before going to sleep. Your body needs at least 3 hours to calm down after a workout.
3. Avoid caffeine and nicotine. The effect of stimulating beverages takes 8 hours to wear off.
4. Avoid alcohol before going to bed. 
5. Avoid drinking plenty of water before going to sleep. 
6. Don’t take naps after 3 PM
7. Relax before going to bed
8. A hot bath before bed might help. 
9. Diss the gadgets and dim the lights in your bedroom
10. Expose yourself to sunlight during the day.