Off the top of my head: 1. The brain only dumps lymph when sleeping. This is how the body removes waste from tissues. 2. The brain actually shrinks during sle

Off the top of my head: 1. The brain only dumps lymph when sleeping. This is how the body removes waste from tissues. 2. The brain actually shrinks during sleep, especially in some areas. This resets circuits so you can create new memories and learn. 3. Studies show that sleep deprivation, especially long term deprivation, results in an increase or accumulation of a couple of proteins associated with the development of dementia. 4. Studies suggest sleep deprivation measurably ages you.