Sleep is not passive. Brain activity changes in organized patterns across stages, including slow-wave sleep and REM sleep.
During sleep, the brain consolidates memories, regulates emotion, and restores metabolic balance. Some research suggests sleep supports the clearance of certain waste products via fluid movement through brain tissue.
Chronic sleep deprivation is associated with impaired attention, mood disruption, and increased health risks, underscoring sleep’s role as a core biological function.