Dementia Risk Factors May Have A Sleep Change In Common

Researchers think heart conditions, chronic stress, and depression may all be linked to a higher risk of developing dementia.

Thankfully, many of these risk factors are “potentially modifiable,” per a standing review from medical journal The Lancet. Treating high cholesterol, staying physically active, and not smoking can all help, for instance.

But a new review published in Science suggested that one thing might link multiple dementia risk factors: how well our brain is able to clear waste while we’re sleeping.

Researcher and neuroscientist Professor Maiken Nedergaard from the University of Rochester Medicine (URM) tried to look at sleep in terms of brain chemicals such as norepinephrine, serotonin, and dopamine.

These “neuromodulators” affect our mood, attention, how awake we feel, and even how well we learn.

Her research noted that “neuromodulators” behave differently during sleep. They run in slow cycles that turn roughly every minute in a manner believed to affect everything from breathing to brain activity.

These sleep changes are also linked to changes in blood vessels called vasomotion, which works independently of our hearts’ pumping motion. One effect of this process is pushing fluid through the brain, helping to clear waste products such as amyloid-beta and tau proteins.

Amyloid plaques come from the buildup of abnormal protein fragments, while tau can turn into stringy proteins that lead to tau tangles. Amyloid plaques and tau tangles have been compared to the “trigger and bullet” of dementia progression.

This paper argued that changes to vasomotion, which happen when we age, face stress, experience some heart conditions, experience poor sleep, or take certain medications, might connect various dementia risk factors.

“Many disorders that increase dementia risk also disrupt the brain’s sleep rhythms”, Prof Nedergaard told URM.

“Our work suggests these may not be separate phenomena. They may be connected through the brain’s ability to clear waste during sleep”.

This paper also mentioned heart rate variability, or the variation of time between heartbeats, as a possible sign of sleep-related brain health.

The study authors hope that tracking this might serve as a non-invasive way to monitor the brain’s waste-clearing systems, potentially helping to spot dementia risk earlier.

“Sleep is not a quiet or inactive state,” Prof Nedergaard said.

“During sleep, the brain shifts into a coordinated rhythm that appears to support one of its most important housekeeping functions.”