of sleep as a period of inactivity.
In reality, sleep is one of the busiest times for the brain.
Throughout the day, billions of neurons generate activity. This activity produces waste products that must be cleared away efficiently. Unlike most organs in the body, the brain lacks a conventional lymphatic drainage system.
For decades, researchers wondered how the brain managed this problem.
The answer emerged with the discovery of the glymphatic system—a network that allows cerebrospinal fluid to circulate through brain tissue and help wash away accumulated waste. During sleep,
