> What I've Learned. WHY Sleep Is Critical for the Body and Brain | Science of Sleep. YouTube, <https://www.youtube.com/watch?v=oTlJnyF3REs>. Accessed 16 Aug. 2021. # WHY Sleep is critical for the Body and Brain | Science of Sleep > Most of us think "less sleep, *more time for* life". This video is all about why sleep is a huge factor in getting more *out of* life. - Arianna Huffington, *The Sleep Revolution* - Less sleep results in a less effective brain and body - Without sleep, the brain loses the ability to consider alternative solutions to problems - Robert Stickgold study: sleep allows for memory consolidation and information processing - During non-REM deep sleep, your brain is reviewing the information you gained during the day at higher speed - While dreaming, the brain simulates scenarios you might have to prepare for - Less sleep makes people more moody and causes them to overreact to things - David K. Randall, *Dreamland* - The military has tested all kinds of methods to keep soldiers awake longer, but ultimately concluded that recovering from lost sleep can only be done by sleeping - The prefrontal cortex's activity decreases when you're sleep-deprived, and it is the only part of the brain capable of self-assessment - Sleep-deprived people lose less fat and more muscle - Less sleep means **more ghrelin**, a hormone which causes your body to retain fat and feel more hungry, **less leptin**, the satiety hormon, and **less melatonin**, which has anti-aging and anti-cancer properties and increases weight loss by increasing brown adipose tissue, **more cortisol**, which is linked to visceral fat and encourages muscle breakdown, and **less HGH**, which stimulates growth, cell reproduction and cell regeneration - 10pm to 2am is when your body generates the most growth hormone, if you're asleep at that time - During the day, the brain produces waste, such as adenosin, which is cleaned up through the glymphatic system - Caffeine bonds to the same receptors as adenosin, tricking the body into thinking it's not tired; it however affects your sleep cycle even six hours before bed - Daniel Pink, *A Whole New Mind*