Better Sleep May Be Incredibly Important to Alzheimer’s Risk
July 21, 2015
Disrupted
sleep may be one of the missing pieces in explaining how Alzheimer’s
starts its damage long before people have trouble with memory. (Photo: Getty Images)
To
sleep, perchance to… ward off Alzheimer’s? New research suggests poor
sleep may increase people’s risk of Alzheimer’s disease, by spurring a
brain-clogging gunk that in turn further interrupts shut-eye.
Disrupted
sleep may be one of the missing pieces in explaining how a hallmark of
Alzheimer’s, a sticky protein called beta-amyloid, starts its damage
long before people have trouble with memory, researchers reported Monday
at the Alzheimer’s Association International Conference.
“It’s
very clear that sleep disruption is an underappreciated factor,” said
Dr. Matthew Walker of the University of California, Berkeley, who
presented data linking amyloid levels with people’s sleep and memory
performance. “It’s a new player on the scene that increases risk of
Alzheimer’s disease.”
Sleep
problems are treatable - and a key next question is whether improving
sleep can make a difference in protecting seniors’ brains.
“Sleep is a modifiable factor. It’s a new treatment target,” Walker said.
Enough
sleep is important for good health generally - seven to eight hours a
night are recommended for adults. When it comes to the brain, scientists
have long known that people who don’t get enough have trouble learning
and focusing. And anyone who’s cared for someone with dementia knows the
nightly wandering and other sleep disturbances that patients often
suffer, long thought to be a consequence of the dying brain cells.
The
new research suggests that sleep problems actually interact with some
of the disease processes involved in Alzheimer’s, and that those toxic
proteins in turn affect the deep sleep that’s so important for memory
formation.
“It may be a vicious cycle,” said Dr. Miroslaw Mackiewicz of the National Institute on Aging, who wasn’t part of the new work.
Walker’s
team gave PET scans to 26 cognitively healthy volunteers in their 70s
to measure build-up of that gunky amyloid. They were given words to
memorize, and their brain waves were measured as they slept overnight.
The
more amyloid people harbored in a particular brain region, the less
deep sleep they got - and the more they forgot overnight, Walker said.
Their memories weren’t transferred properly from the brain’s short-term
memory bank into longer-term storage.
What’s
the risk over time? Two sleep studies tracked nearly 6,000 people over
five years, and found those who had poor sleep quality - they tossed and
turned and had a hard time falling asleep - were more likely to develop
mild cognitive impairment, early memory problems that sometimes lead to
Alzheimer’s, said Dr. Kristine Yaffe of the University of California,
San Francisco.
Sleep
apnea - brief interruptions of breathing that repeatedly awaken people
without them realizing - caused a nearly two-fold increase in that risk,
Yaffe said. She recommended that people at risk of Alzheimer’s be
screened for sleep disorders, especially apnea, which has effective
treatment.
“There’s a lot of evidence that we need to pay more attention” to sleep in seniors, she said.
Animal
studies give clues to the biology behind these changes. Dr. David
Holtzman of Washington University in St. Louis reported a series of mice
experiments that found amyloid production is highest during waking
hours and lowest during deep sleep. Depriving mice of sleep spurred
toxic amyloid build-up and, intriguingly, once those deposits began, the
mice stayed awake longer on their own. Holtzman also checked
Alzheimer’s other bad actor, the protein tau that forms tangles in the
brain, and found the same effect on deep sleep.
Another
hint came a few years ago, when University of Rochester scientists
reported that the brain uses sleep to flush out toxic debris. They
injected mice brains with amyloid and watched it clear faster while they
slept.
end quote from:
https://www.yahoo.com/health/better-sleep-may-be-incrediably-important-for-124660349937.html
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