Proper sleep clears amyloid plaques, consolidates and connects memories, and cortisol is a necessary circadian hormone that peaks early morning to promote wakefulness.
REM sleep enhances creativity, memory consolidation, cellular restoration, metabolic regulation, and circadian synchronization, enabling human cultural and cognitive evolution.
Regularly getting only five hours of sleep impairs daytime functioning, harms mental and physical health, and may increase risk of dementia and Alzheimer's.