There's a new story to file under the "beware of too little sleep" category, and it's a pretty ominous one: that a lack of deep sleep could help pave the way to Alzheimer's disease. Actually, that there's some sort of relationship has long been established from the reverse—those with Alzheimer's often have sleep issues. But NPR reports on research conducted by Jeffrey Iliff, that has found, as the Oregon Health & Science University researcher puts it, that "changes in sleep habits may actually be setting the stage" for Alzheimer's. Two separate studies got us to that statement, NPR explains: In 2009, researchers with Washington University in St. Louis who studied sleep-deprived mice found that the amyloid plaques that are a signature of Alzheimer's formed more rapidly in the creatures' brains. In 2012 came part II, thanks to Iliff, his team, and their research on snoozing mice and discovery of the previously unknown glymphatic system.
As Iliff explained in a 2014 TED Talk, the body's lymphatic system clears out waste, but there's no room in the brain for such a system—and one does indeed exist. "Clean, clear fluid called cerebrospinal fluid ... fills the space that surrounds the brain," he says. Blood vessels "extend from the surface of the brain down to reach every single cell in the brain," he adds, noting that the CSF travels along the outside of those vessels to reach every part of the brain, taking waste with it and depositing it into the blood. Among that waste, in mice: the toxins that form the amyloid plaques. Next up is seeing if the same fluid movement/toxin removal happens in our brains during deep sleep. Iliff and his fellow researchers hope to put that to the test before the year is out—so long as they can find enough volunteers who are able to sleep deeply in the loud and narrow tunnel of the ultra-sensitive MRI unit that will be used to observe the changes in their brains.