May 15, 2018
Not sleeping for just one night produced brain changes typical of Alzheimer’s disease, a new study reports. The study found that a single night of not sleeping led to increased levels of beta-amyloid, a toxic protein that builds up to form plaques in the brains of those with Alzheimer’s disease.
The study was small, involving only 20 healthy men and women who ranged in age from 22 to 72. But the new research adds to a growing body of evidence linking sleep to brain health.
“This research provides new insight about the potentially harmful effects of a lack of sleep on the brain and has implications for better characterizing the pathology of Alzheimer’s disease,” said George F. Koob, director of the National Institute on Alcohol Abuse and Alcoholism, part of the National Institutes of Health, which funded the study.
The formation of beta-amyloid plaques is a hallmark of Alzheimer’s disease. As plaques build up in the brain, brain cells die. Memory loss and thinking problems ensue and worsen as plaques spread through the brain.
For the current study, volunteers underwent PET brain scans after a night of rested sleep, and again after staying awake for about 31 hours. Remarkably, the researchers found that beta-amyloid levels increased about 5 percent after only a single night of staying awake.
Beta-amyloid levels rose in particular in the hippocampus and the thalamus, areas of the brain critical for memory that are also affected early in the course of Alzheimer’s disease. Participants with the largest elevations in beta-amyloid also reported being in a worse mood after the night of lost sleep.
The scientists did not look at whether the elevated beta-amyloid levels subsequently subsided after a sound night’s sleep. The findings were published in the Proceedings of the National Academy of Sciences.
It’s long been known that people with Alzheimer’s disease tend to sleep poorly at night, spending more time awake. But scientists have been uncertain whether poor sleep contributes to Alzheimer’s onset, or if troubled sleep is actually an early symptom of Alzheimer’s. The new study sheds further light on the links between sleep and dementia.
Earlier studies have shown that lack of nighttime sleep or waking up several times during the night may be bad for the brain and may increase the risk of Alzheimer’s disease, in part by possibly contributing to beta-amyloid buildup.
Additional research suggests that one reason why poor sleep may be linked to Alzheimer’s is that sleep may help to clear toxic molecules from the brain.
Earlier studies have also shown that poor nighttime sleep can lead to memory and thinking problems, even in healthy people. People with a common breathing disorder called sleep apnea, which causes sleepers to awaken briefly hundreds of times during the night, has likewise been linked to memory problems and an increased risk of dementia.
But poor sleep, as well as sleep apnea, is a common problem in the elderly. Just because you don’t sleep well doesn’t mean you will get Alzheimer’s disease. A sound night’s sleep, though, may be a critical component of a healthy lifestyle – and might even help to keep Alzheimer’s at bay. And physical exercise during the day is a good way to help to bring a sound sleep at night.
By www.ALZinfo.org, The Alzheimer’s Information Site. Reviewed by Marc Flajolet, Ph.D., Fisher Center for Alzheimer’s Research Foundation at The Rockefeller University.
Source: Shokri-Kojori E, et al: “Beta-Amyloid accumulation in the human brain after one night of sleep deprivation.” Proceedings of the National Academy of Sciences. April 2018