Just one night without enough sleep can cause harmful proteins to build up in the brain, increasing the risk of Alzheimer’s disease, according to a new study.
Past studies already linked insufficient sleep to increased risk of Alzheimer’s and other chronic diseases — but this recent study from Washington University,published in the Annals of Neurology, discovered what insomnia actually does to the brain.
One of the functions of sleep is to clear the brain of waste, including amyloid beta proteins which can bond with each other and form plaques on nerve cells. These plaques build up in the brains of people with Alzheimer’s disease.
People with a genetic tendency for Alzheimer’s disease have higher than normal levels of beta amyloid proteins, even before they develop symptoms. After a night without sleep, these higher levels appeared in the healthy study participants.
Inadequate sleep has been linked to a 1.5 fold increase in the odds of developing Alzheimer’s. It’s not surprising, therefore, that research shows that sleep disorders such as sleep apnea increase the risk.
In the study, eight participants with no previous sleep or memory problems were instructed to either stay awake all night, get a normal night’s rest, or use the drug sodium oxybate to help them sleep. The sleep aid is supposed to increase the period of deep, dreamless sleep when the brain is thought to restore itself.
The scientists tested the cerebrospinal fluid surrounding each participant’s brain for amyloid proteins. Measurements were taken before the night of the test, and then every 2 hours the next day, to show how the night of sleep or no sleep affected the accumulation of these proteins in the brain.
Study participants who went without sleep for just one night had a 25-30% increase in the beta-amyloid proteins in their cerebrospinal fluid, bringing the levels to what researchers would expect to see in people who have genes for Alzheimer’s disease. Before the test, the participants all had normal levels. The pills designed to promote the deep sleep did not affect the levels of amyloid protein.
In a healthy person, normal sleep eliminates waste and restores the brain each night. But repeated nights of insufficient rest may overwhelm the brain’s recovery system, allowing amyloid proteins to build up and form plaques which interfere with the brain’s functioning.
For information on Alzheimer’s and also long term care insurance, see Alzheimer’s Section on the Guide To Long Term Care.