During sleep, the body undergoes essential recovery processes. The brain consolidates memories, clears waste, and supports emotional regulation. Hormones are released to help with growth, metabolism, and immune function. Muscles and tissues repair themselves, and energy stores are replenished.

Sleep occurs in cycles—light sleep, deep sleep, and REM (dreaming) sleep—each with distinct functions. Adults generally need 7–9 hours of sleep for optimal health. Chronic sleep deprivation affects mood, focus, immunity, and increases the risk of obesity, heart disease, and diabetes. Good sleep hygiene—regular bedtime, dark room, limiting screens—can improve sleep quality.