Sleep Is When Your Brain Literally Cleans Itself

During sleep, the brain's glymphatic system flushes out metabolic waste products — including beta-amyloid, which accumulates in Alzheimer's disease. This system is nearly 10 times more active during sleep than when awake. Poor sleep doesn't just make you tired — it allows toxic proteins to build up in the brain, with long-term neurological consequences.

Source: Science (2013) — Lulu Xie et al., University of Rochester