Walker and his team studied 32 septuagenarians, running brain scans to monitor the levels of beta-amyloid in each one for up to six years. People who got less deep sleep had more beta-amyloid, they found. Other studies have found a similar association between a lack of deep sleep and higher levels of the protein tau in the brain. “We are now learning that there is a significant relationship between sleep and dementia, particularly Alzheimer’s disease,” Matthew Walker, a professor of neuroscience and psychology at the University of California, Berkeley, told NPR. “There is something about this deep sleep that is helping protect you.” The working theory, which dates back to a 2013 study, is that deep sleep activates a “dishwasher” in the brain: waves of fluid that flow into the brain during sleep that remove things like beta-amyloid and are preceded by large, slow electrical waves. This “dishwasher” helps clean out your brain every night — and going without it could be disastrous, apparently. Naturally, scientists are now focused on figuring out ways to induce such waves in the hopes without deep sleep, so that they can purposefully activate the processes that “clean” the brain and make dementia less likely. The news likely won’t help parents get more sleep. After all, squeezing more time out of the day is mostly just about cutting smaller pieces in a pie. And sometimes, sleep just can’t be found — whether a kid is sick or whether a parent is having their first baby jitters, constantly checking the baby monitor. But the study is a sobering reminder that sleepless nights have real consequences.
