TL;DR
Researchers have long tied sleep to the brain's waste clearance, and that waste includes amyloid-beta, the sticky protein behind Alzheimer's plaques. A team at Finland's University of Oulu tried to run that cleanup while people were awake, pairing a temporary blood-pressure-lowering drug with whole-body vibration in 29 healthy adults. Afterward, blood levels of two forms of amyloid-beta and a brain-injury marker all rose, which the researchers read as proteins leaving the brain, and the pattern resembled what happens in sleep. Brain scans suggested the proteins passed straight into the large veins at the back of the brain, a route the team says had not been seen before, even in animals. Just as striking is the readout: an ordinary blood draw showing what the brain had just let go. No one with dementia was in this first study; people with early memory impairment are next. For our odds on when awake brain-clearing reaches those patients, and the timeline of breakthroughs that leads there, subscribe.
Below the line, for paid subscribers: The full story: where it stands, how we got here and what's dated next; our labeled speculation on what it adds up to; and every source.