Worldwide, there are over 46.8 million people suffering from dementia in 2017, of which the leading kind is Alzheimer’s. This number is expected to rise to 131.5 million by 2050, reports Alzheimer’s.net. A debilitating disease that destroys memory and slows brain function, Alzheimer’s is one of the most common causes of death in people over 65.
New research from Washington University School of Medicine in St. Louis, Stanford University, and Radboud University Medical Centre in the Netherlands has found a connection between disruptive sleep and Alzheimer’s disease. The study revealed that a singular night of poor sleep in middle-aged adults increased the brain protein amyloid beta, which is linked to Alzheimer’s. The study also discovered that a week of restless sleep enhances tau, another brain protein that is associated with brain damage in Alzheimer’s.
While previous studies have shown how disruptive sleep enhances the risk of cognitive problems, it was never clear how it actually damages the brain – until now. The researchers studied 17 adults for two weeks, all aged 35-65 and generally healthy without cognitive or sleep issues. Each adult wore an activity monitor to measure the amount of sleep they got each night. Using data from the monitors, researchers compared the levels of amyloid beta and tau in each participant after poor and restful nights.
Across the spectrum, researchers discovered there was a 10% increase in levels of amyloid beta after one night of disruptive sleep. “We showed that poor sleep is associated with higher levels of two Alzheimer’s-associated proteins,” says David M. Holtzman, head of Washington University School of Medicine’s Department of Neurology and the study’s senior author. “We think that perhaps chronic poor sleep during middle age may increase the risk of Alzheimer’s later in life.”
Despite the study results, however, Associate Professor of Neurology Yo-El S Ju says it is unlikely that a single night of poor sleep will greatly enhance the risk of developing Alzheimer’s, because amyloid beta levels will generally lower after a good night’s sleep. “The main concern is people who have chronic sleep problems,” she explains. “That may lead to chronically elevated amyloid levels, which animal studies have shown lead to increased risk of amyloid plaques and Alzheimer’s.”
Unfortunately, sleeping well and consistently does not guarantee you will lower your risk of developing Alzheimer’s, Ju cautions. “We can’t say whether improving sleep will reduce your risk of developing Alzheimer’s. All we can really say is that bad sleep increases levels of some proteins that are associated with Alzheimer’s disease.”