Skip to main content

While you sleep, your brain clears out toxins that are linked to Alzheimer's

  • Author:
  • Updated:

A peaceful night of sleep clears the mind — literally, according to neuroscientist Jeff Iliff.

In a recent TEDMED talk, the University of Rochester researcher says that healthy brains use the downtime of sleep to basically clean house.

“When the brain is awake and is at its most busy, it puts off clearing away the waste from the spaces between its cells until later,” says Iliff. “Then when it goes to sleep and doesn’t have to be as busy, it shifts into a kind of cleaning mode.”

Iliff was referencing a study that he and his colleagues from the University of Rochester Medical Center published last year. They discovered that the sleeping brains of mice wash away debris accumulated during a day’s worth of action-packed thinking and doing — the very same debris that clogs the brain of an Alzheimer’s patient.

Every cell in our body feeds on nutrients and produces metabolic waste as a byproduct. It's a bit like "engines producing exhaust," says naturopathic doctor Angele Besner.

"This cellular byproduct becomes toxic to cells if it’s allowed to accumulate and hang round too long," Besner wrote on her blog. "Brain cells are delicate and especially vulnerable to this kind of damage."

When we enter the dream world of sleep, explains Iliff, brain cells shrink, opening up the space between them and allowing cerebrospinal fluid to wash away these toxic substances. “It’s like a dishwasher,” explains study lead author and neurosurgeon Dr. Maiken Nedergaard in an interview with NPR.

But not every brain is able to clean itself.

“In patients with Alzheimer’s disease, [the waste product] amyloid beta builds up and aggregates in the spaces between the brain’s cells instead of being cleared away like it’s supposed to be,” explains Iliff.

Indeed, amyloid beta buildup is a longtime hallmark of the disease, explains Alzheimer’s Foundation of America, dating back to an autopsy of the first-identified Alzheimer’s patient in 1906.

Many neurological disorders — Alzheimer's, yes, but also dementia and stroke — are linked to sleep disorders, Nedergaard tells Science, which noted that "the study suggests that lack of sleep could have a causal role, by allowing the byproducts to build up and cause brain damage."

"This could open a lot of debate for shift workers, who work during the nighttime,” Nedergaard told Science. "You probably develop damage if you don’t get your sleep."

Next Up

US Secretary of Defense COVID vaccine flickr

Minnesota's COVID-19 update for Friday, May 13

The next update will be provided Monday.


Minnesota part of the top 2 hurricane force wind events since 2004

Photo above shows the ominous view in Marshall, Minnesota as a dangerous line of storms approached Thursday afternoon.

Screen Shot 2022-05-13 at 9.24.48 AM

DFL efforts to pass abortion, reproductive health bills blocked in Senate

The push to pass a slate of abortion and healthcare-related bills comes after a leaked Supreme Court opinion draft indicated Roe v Wade will be overturned.

Screen Shot 2022-05-13 at 8.16.56 AM

Teen hospitalized after going missing for 40 mins in St. Croix River

The teen was located around 40 minutes after he had gone under water.

Screen Shot 2022-05-13 at 7.23.52 AM

Thursday performances of Runestone! canceled due to COVID cases

This weekend's performances are still going ahead, History Theatre says.

Screen Shot 2022-05-12 at 7.12.27 PM

Storms cause grain bin to fall, killing one in Kandiyohi County

The National Weather Service confirmed the death on Thursday evening.


Ferocious winds, possible tornadoes leave destruction in MN

Numerous reports of tornadoes and nearly 100 mph straight-line winds.


Canoe carrying 4 overturns near St. John's University

Of the four, only one was wearing a lifejacket when the boat capsized Wednesday.

pexels beer bar craft brewery

MN's craft alcohol makers back new push to loosen state's liquor laws

The pushback includes loosening restrictions on growler sales for bigger craft breweries and a more direct line of spirit sales to customers.

Screen Shot 2022-05-12 at 8.02.19 PM

Severe thunderstorm warnings in the Twin Cities

It's the second night in a row that severe storms are hitting the metro.


Twin Cities placed in tornado watch ahead of intense line of storms

Photo above is a view from Marshall as the line of storms moved through Thursday evening.