Less sleep can increase Alzheimer's risk

New findings suggest sleep deprivation and chronic shut-eye disturbances may be associated with a higher risk of developing Alzheimer's disease. Previous studies had linked sleep deprivation to the risk of dementia and Alzheimer's disease in animals but this is the first time that scientists found the same pattern in humans, HealthDay, reported. Researchers at Washington University's Sleep Medicine Center discovered the pattern while working on amyloid beta, a brain marker for the Alzheimer's disease. Their findings showed that amyloide beta Levels increase in the day time and decrease during sleep. The pattern which is stronger in healthy young people begins to flatten in older adults when sleep periods are often shorter and more prone to disruption. “In healthy people, levels of amyloid beta drop to their lowest point about six hours after sleep, and return to their highest point six hours after maximum wakefulness,” said Dr. Randall Bateman, associate professor of neurology. “We looked at many different behaviors, and the transitions between sleep and wakefulness were the only phenomena that strongly correlated with the rise and fall of amyloid beta in the spinal fluid.” The study further revealed that in elderly people with brain plaques linked to Alzheimer's disease, normal amyloide beta high and lows is eradicated, and the substance levels are close to constant. The latest finding suggest that like animals, sleep deprivation and disturbances in humans may also be associated with development of Alzheimer's disease. “We've known for some time that significant sleep deprivation has negative effects on cognitive function comparable to that of alcohol intoxication,” said lead researcher Dr. Stephen Duntley. “But it's recently become apparent that prolonged sleep disruption and deprivation can actually play an important role in pathological processes that underlie diseases. This connection to Alzheimer's disease isn't confirmed yet in humans, but it could be very important.” The study suggested that the brain's low activity during sleep allows the body to clear amyloid beta through the spinal fluid. The study also showed that more research is needed to explore how disrupted sleep in young people disrupts the normal fluctuation rhythm of spinal amyloid beta, and how sleep aids may help maintain this wave-like pattern. "It's still speculation, but there are tantalizing hints that better sleep may be helpful in reducing Alzheimer's disease risk," concluded Duntley. "We know from a number of studies that exercise enhances sleep, and research also has shown that exercise is associated with decreased risk of Alzheimer's. Sleep might be one link through which that effect occurs."