Discovered by Maiken Nedergaard at the University of Rochester in 2013, the glymphatic system is a network of channels surrounding cerebral blood vessels through which cerebrospinal fluid flows during sleep, flushing metabolic waste from the brain parenchyma. During deep non-REM sleep, glial cells shrink by up to 60%, expanding the interstitial space and allowing dramatically increased cerebrospinal fluid flow. This is when amyloid-beta, tau, and other metabolic byproducts of neuronal activity are cleared.
Alzheimer's is not simply a disease that arrives in old age. It is a failure of waste clearance that accumulates across decades of compromised sleep.
Protecting Glymphatic Function
- Consistent sleep timing, a cool sleep environment (17–19°C), no alcohol within 4 hours of bed
- Avoiding stimulants after 2pm
- Exercise increases glymphatic flow both acutely and chronically
- Lateral (side) sleeping positions improve glymphatic flow compared to supine
- Omega-3 fatty acids have preliminary evidence for supporting astrocyte function
glymphatic systembrain healthsleepAlzheimer'samyloid betacognitive health