A new study published in the Journal of Clinical Sleep Medicine has found that there is a new connection between Alzheimer’s disease and quality sleep. Researchers followed middle-aged and older adults, measuring their brain volumes years after analyzing sleep quality. They found that less time spent in slow-wave and REM sleep correlated with smaller volumes in areas such as the hippocampus and inferior parietal lobe, which are both known to be early targets of Alzheimer’s disease.
Deep Sleep
During deep sleep, also called slow-wave sleep, your brain slows down and begins restorative processes. This is when the glymphatic system clears out metabolic waste, including the amyloid-beta and tau proteins that build up in Alzheimer’s disease. If you don’t get enough deep sleep, your brain doesn’t get a chance to recycle the day of what you don’t need.
REM sleep plays a different, but equally vital role. It’s when most dreaming occurs and is essential for memory formation and emotional processing. In older adults, delays in reaching REM sleep are now being linked to a rise in Alzheimer’s disease.
A 2023 study even found that every 1% drop in deep sleep corresponded with a 27% increased risk of developing dementia. While these correlations are suggestive, they strongly indicate that fragmented or shallow sleep may facilitate the buildup of toxic proteins and impair brain structure over time.
Experts agree that the link between poor sleep and cognitive decline creates issues for the other. On one hand, poor sleep may increase the risk of Alzheimer’s. However, the early brain changes in Alzheimer’s may start disrupting sleep even before noticeable memory problems appear.
In a study by UCSF, people who reported frequent nighttime awakenings and trouble falling asleep experienced faster brain shrinkage over time. Even when researchers controlled for age, mood, and lifestyle, the link remained.
The Warning Signs
Alzheimer’s disease and dementia do present warning signs that are important to note for your physician. With your sleep patterns, it could be that it takes you longer to fall asleep or that you wake up frequently throughout the night. These could be red flags if you have already tried eliminating easy disruptions like caffeine late in the day or screens from the bedroom that emit blue light.
Another concern is sleep apnea warning signs, like heavy snoring or waking up gasping for air. According to the National Institute on Aging, sleep apnea increases dementia risk, particularly in women. This disruption limits the flow of oxygen to the brain, impacting your mind’s memory storage.
Early sleep disturbances in older age may be noticeable in your friends and family with mood swings, lack of concentration, or short-term memory struggles. Staying physically active and socially connected also boosts sleep and brain health. A brisk daily walk, paired with mental stimulation like puzzles, reading, or conversation, can promote more restorative sleep.
Thinking now about how you can create and maintain a healthy sleep pattern is an important place to start. Just like infants need a sleep schedule, so do adults. Maintaining a regular sleep schedule every day, including weekends, helps your body know when REM sleep is patterned. Creating a soft, cool sleep environment with light walls, blackout curtains, and free from electronics brings a comforting mood that allows your bedtime to be your sanctuary. Think about adding essential oils like lavender and a sound machine for white noise.
Treating underlying issues like insomnia or sleep apnea can make a measurable difference. Cognitive behavioral therapy for insomnia (CBT-i) has been shown to increase time spent in deep sleep, which is something medications can rarely help on their own.
While sleep alone won’t prevent Alzheimer’s, it may be one of the most powerful tools we have for reducing risk, especially when combined with healthy lifestyle choices and early intervention. From our CBT services to treating sleep apnea, connect with the Alaska Sleep Clinic to schedule your free consultation today.
