Could delaying — or even preventing — dementia be as simple as routinely getting a good night’s sleep?
Recent research suggests that poor sleep quality may play a surprisingly pivotal role in the erosion of working memory and the development of Alzheimer’s. Some scientists even believe that doctors will someday treat the disease by helping their patients improve their sleep patterns.
In a 2019 study, Audrey Duarte, PhD, and her team at Georgia Tech University found that poor sleep hampered the ability of older participants (and African Americans of all ages, due to race-related stress) to recall information about previous events.
“The night-to-night variability in the older study participants had a major impact on their performance in tests aimed at evaluating episodic memory,” Duarte says. “The association between sleep and memory has been known, but this study’s novelty is showing that the connection is particularly evident for older adults and Black participants, regardless of age.”
More recently, researchers at Boston’s Brigham and Women’s Hospital followed sleep patterns and dementia cases among 2,812 Medicare beneficiaries and reported in a 2020 analysis that those who slept five hours or less each night were twice as likely to develop dementia as those sleeping seven to eight hours.
But just as poor sleep may lead to cognitive dysfunction, improving your sleep patterns may delay — or even prevent — the condition. That’s what University of California, Berkeley neuroscientists Matthew Walker, PhD, and Joseph Winer, PhD, discovered in a 2020 study when tracking the growth rate of beta-amyloid protein (a suspected precursor of dementia) in the brains of 32 participants ranging in age from 60 to 89. Those who experienced fragmented sleep periods and less non-REM (rapid eye movement) slow-wave sleep were more likely than their sounder-sleeping counterparts to produce excessive beta-amyloid in their brains.
Mayo Clinic scientists in a 2019 paper reported a similar link between sleep apnea and the growth of dementia-linked tau protein. After controlling for other factors that affect tau production, the research team found 4.5 percent more of the protein in the brains of those exhibiting apnea issues.
If sleep quality is a biomarker for dementia, says Winer, then physicians can theoretically project a timetable for the disease’s development while working with patients to delay its arrival.
“If deep, restorative sleep can slow down this disease, we should be making it a major priority,” he says. “And if physicians know about this connection, they can ask their older patients about their sleep quality and suggest sleep as a prevention strategy.”
By the Numbers: How Sleep Affects Long-Term Memory
Likelihood that seniors who slept five hours or less per night will develop dementia compared with their peers who slept seven to eight hours, according to a Brigham and Women’s Hospital analysis.
Percentage more dementia-linked tau protein found in the brains of participants who suffered from sleep apnea compared with those who slept soundly, according to a 2019 Mayo Clinic study.
Percentage decrease in memory-related brain activity among Black study participants, who slept 36 fewer minutes per night than their non-Black counterparts, according to a Georgia Tech analysis.