Deep Sleep and Alzheimer’s Disease
Deep sleep might play a role in preventing declines in brain health that can lead to Alzheimer’s disease, which is the most prevalent form of dementia. A recent study conducted by researchers from the University of California (UC) Berkeley along with Stanford University and UC Irvine examined 62 older adults who were cognitively healthy. The findings revealed that those with brain changes related to Alzheimer’s performed better on memory tests when they experienced more deep sleep.
This effect was noted regardless of factors such as education and physical activity—both known to help maintain cognitive resilience in older age. Interestingly, participants who had similar Alzheimer’s-related brain changes but did not get enough deep sleep didn’t perform as well on the tests. In contrast, those with minimal amyloid deposits saw little impact from their sleep quality.
The results, published in May 2023, suggest that adequate deep sleep may assist in managing memory loss as dementia begins to set in.
As neuroscientist Matthew Walker from UC Berkeley puts it, “Think of deep sleep almost like a life raft that keeps memory afloat, rather than memory getting dragged down by the weight of Alzheimer’s disease pathology.” It’s exciting, he adds, because there are actionable steps we can take to improve sleep even in older adults.
The study aligns with earlier research showing that people with disrupted sleep can accumulate amyloid-beta proteins in their brains. However, it’s tricky as poor sleep can be both a symptom and a risk factor for Alzheimer’s, making it difficult to discern cause from effect. Sometimes, these amyloid deposits might just indicate the presence of Alzheimer’s without being its root cause.
Nevertheless, amyloid-beta levels are often used as markers for the disease, as studies suggest they and another protein, tau, can obstruct brain cells years before symptoms arise. Walker’s previous research also identified significant amyloid-beta levels that can disrupt deep sleep—and that contributes to memory impairment.
Some individuals, however, seem to resist the cognitive decline tied to Alzheimer’s, even with high amyloid-beta levels. To investigate why, Walker and his team monitored participants’ brain activity during sleep and had them complete memory tests afterward. Among those with elevated beta-amyloid, those who got quality deep sleep exhibited better cognitive function.
The researchers noted that this benefit was specifically linked to non-rapid eye movement slow wave sleep, rather than other sleep stages or frequencies.
Future, longer-term studies are required to determine if enhancing deep sleep over several years can truly help maintain cognitive function despite increasing amyloid-beta levels. This research adds to a growing body of evidence that suggests sleep might be a modifiable risk factor for Alzheimer’s, potentially allowing the brain the time it needs to clear away waste accumulated throughout the day, emphasizing the importance of sleep quality.
With a certain level of brain pathology, one isn’t necessarily fated to experience cognitive symptoms or memory issues, as stated by Zsófia Zavecz, the lead author of the study. Even though some may show biological signs of progressing toward Alzheimer’s, lifestyle choices like sleep quality can help mitigate these effects.
This relatively small study also underscores why naturally achieving good sleep might be preferable to using sleep medications. Previous findings indicate that those who use sleeping pills may have lower levels of amyloid proteins in their cerebrospinal fluid; however, these medications can have side effects and may not encourage deep sleep.
To promote better sleep, Zavecz recommends avoiding caffeine in the late afternoon, engaging in physical activity, reducing screen time, and perhaps enjoying a hot shower before bed.
As you rest, researchers are diligently tackling the complex challenges posed by Alzheimer’s, a condition that impacts millions globally.
The study was published in BMC Medicine.
