All animals need sleep and people have been fascinated by sleep throughout history. There are different stages of sleep including light, deep, and REM sleep. During REM sleep, the brain is active while the body is paralyzed, which is important for memory, learning, and creativity. Most adults need around 8 hours of sleep per night but many people suffer from sleep deprivation or disorders. Not getting enough quality sleep can seriously impact health, mood, and cognitive performance.