Sleep May be Key to Reducing Alzheimer's Risk

Alzheimers disease marker amyloid beta increases and decreases based on sleep

(RxWiki News) Could a good night's sleep be a key to reducing the risk of developing Alzheimer's disease? It's still speculation, but a link between sleep and the rise and fall of a marker for the disease have given scientists hope.

An Alzheimer's disease marker in the spinal fluid that increases and decreases in a pattern similar to sleep cycles reinforced a link between poor sleep and increased Alzheimer's risk.

"Get plenty of sleep each night."

The pattern is strongest in healthy individuals. It is suspected that the brain's relative inactivity could provide an opportunity to finish clearing the Alzheimer's marker, a byproduct of brain activity called amyloid beta, which has been linked to Alzheimer's disease.

Dr. Stephen Duntley, professor of neurology at Washington University School of Medicine, said there are tantalizing hints that better sleep may help in reducing the risk of Alzheimer's disease. He noted that a number of studied have indicated that exercise enhances sleep and also that exercise is linked to a decreased risk of Alzheimer's. Sleep might be the link through which that effect occurs, he said.

Researchers followed three groups of participants, including a group age 60 and older who tested positive for the presence of amyloid beta plaques in the brain, a group over 60 who did not have plaques, and a group of healthy individuals between the ages of 18 and 60.

Investigators utilized a spinal tap to monitor amyloid beta in the spinal fluid hourly for 24 to 36 hours, and videotaped patient activities and monitored their brain activity during that period.

Amyloid beta was nearly constant in the group with brain plaques. However, in the other two groups, the levels regularly increased and decreased in a snake-like pattern. The pattern was most pronounced in younger participants, but began to flatten in older adults with sleep periods that were shorter and more prone to interruption.

Older adults tend to sleep less and have fewer periods of deep slumber. The disruptions become more pronounced with age, while the risk of developing Alzheimer's also increases with age.

In healthy individuals amyloid beta dropped to the lowest point six hours after going to sleep and returned to its highest point six hours after maximum wakefullness.

Researchers are currently working to determine whether deliberate sleep interruption in young healthy subjects disrupts the normal daily decrease in spinal amyloid beta. They also plan to test whether sleeping pills could improve sleep to help maintain the rise and fall of amyloid beta.

The clinical study was published in September's Archives of Neurology.

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Review Date: 
September 28, 2011