Deep Sleep and Brain Health
Deep sleep might help prevent declines in brain health that can lead to Alzheimer’s disease, the most common type of dementia.
Researchers from the University of California, Berkeley, Stanford University, and UC Irvine studied 62 older adults who were cognitively healthy. They discovered that those showing brain changes typical of Alzheimer’s performed better on memory tests when they achieved more deep sleep.
This improvement seemed to happen regardless of factors like education, physical activity, and social connections, all of which generally bolster cognitive resilience in older individuals.
Interestingly, those with similar brain changes but who didn’t get as much deep sleep didn’t do as well on memory tests. In contrast, for individuals with fewer brain deposits, sleep did not significantly impact performance.
The findings, published in May 2023, suggest that sufficient deep sleep could help slow down memory decline as dementia begins to manifest.
“Think of deep sleep as a life raft keeping memory afloat amidst the challenges of Alzheimer’s pathology,” noted UC Berkeley neuroscientist Matthew Walker.
“This is encouraging, especially since we can take steps to improve sleep, even among older adults.”
This study aligns with previous research indicating that a buildup of amyloid-beta proteins—often found in the brains of people with sleep disturbances—may impact cognitive function.
However, poor sleep is both a risk factor for and a symptom of Alzheimer’s, complicating the understanding of cause and effect. The presence of amyloid-beta proteins might simply indicate Alzheimer’s rather than serve as a causative factor.
Yet, amyloid-beta levels are often used as markers for Alzheimer’s because research indicates they can begin to accumulate long before any symptoms appear.
Walker’s previous work highlighted that substantial amyloid-beta can disrupt deep sleep, impairing memory processes.
Strikingly, some individuals manage to resist the cognitive decline associated with Alzheimer’s despite having high levels of amyloid-beta. To investigate this, researchers monitored participants’ brain activity during sleep and later administered memory tests.
Among those with similar high amyloid-beta levels, the quality of deep sleep made a noticeable difference in cognitive performance, particularly in non-rapid eye movement sleep versus other sleep stages.
More extensive research is needed to see if enhancing deep sleep over several years can maintain cognitive function even as amyloid-beta levels rise.
This study contributes to a growing body of evidence suggesting that sleep might be a modifiable risk factor for Alzheimer’s, potentially allowing time for the brain to cleanse itself of waste accumulated during the day. The quality of sleep also seems to play a vital role.
“With some level of brain pathology, you’re not doomed to experience cognitive symptoms or memory problems,” stated Zsófia Zavecz, a UC Berkeley neuroscientist and study lead.
While molecular changes may signal a progression toward Alzheimer’s, Zavecz argues that lifestyle factors, such as sleep—especially deep sleep—can mitigate those effects.
The study suggests that naturally achieving quality sleep might be preferable to using sleeping pills for rest.
Other research indicates that sleeping pill users often have lower levels of amyloid-beta proteins in their brain’s cleaning fluid. However, these medications may lead to shallow sleep rather than deep rest, which is more beneficial.
To promote better sleep, Zavecz recommends avoiding coffee late in the day, engaging in physical activity, steering clear of screens before bed, and perhaps enjoying a hot shower prior to sleep.
As researchers continue their efforts to unravel Alzheimer’s-related challenges, the message is clear: sleep may play a crucial role in brain health.
This study was published in BMC Medicine.
