Glymphatic Flow Boosted by Slow-Wave Sleep and Exercise Reduces Amyloid Load in Human Imaging Studies

The glymphatic system, mapped in rodent models by Nedergaard's group since 2012, uses perivascular channels to expel amyloid-beta and tau during deep sleep. Human data now link higher slow-wave sleep duration to 15-20% lower CSF tau levels over two years in the Wisconsin Registry for Alzheimer's Prevention cohort. Exercise appears additive: participants combining brisk walking with consistent 7-hour sleep showed the largest clearance gains. These findings connect to broader aging research where interventions targeting fluid dynamics outperform single-target drugs in early trials. Limitations include small samples and lack of long-term dementia incidence data. Next steps require phase-2 trials testing sleep-optimized exercise in amyloid-positive individuals over five years to measure conversion rates. If clearance improvements exceed 30% without cognitive decline, the approach could shift prevention guidelines by 2028.