The exact cause of Alzheimer’s is unknown. However, research indicates that age, genetics, and certain lifestyle habits (like smoking and excessive drinking) can all contribute to your risk of developing the neurodegenerative disorder—as can sleep, per new findings.
A 2025 study published in the Journal of Clinical Sleep Medicine found that low levels of slow-wave sleep (SWS) and rapid eye movement (REM) sleep can weaken regions of the brain that are susceptible to Alzheimer’s, making you more vulnerable to the disease over time.
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A normal sleep cycle includes four stages, including deep sleep (SWS) and REM sleep. During deep sleep (stage three), your body and mind is focused on recovery and growth. Muscle tone, pulse, and breathing decrease exponentially while the brain harnesses power to fuel insightful thinking, creativity, and memory, according to the Sleep Foundation. A spike in brain activity occurs in REM sleep, during which you might experience intense, vivid dreams. This stage is "essential" for cognitive function, explains the organization.
The study raised the question of whether one’s risk of developing Alzheimer’s is dependent on getting enough deep sleep and REM sleep.
The authors analyzed sleep data from 270 individuals (median age of 61 years) who didn’t have a history of stroke, dementia, or other brain trauma. Participants completed a sleep study to assess baseline sleep architecture and then underwent advanced imaging to measure brain volumes. Follow-up visits were conducted 13-17 years after the initial sleep study.
Researchers detected "smaller volumes in critical brain regions, particularly the inferior parietal region, which is known to undergo early structural changes in Alzheimer’s disease," among participants who got poor SWS and REM sleep.
"Our findings provide preliminary evidence that reduced neuroactivity during sleep may contribute to brain atrophy, thereby potentially increasing the risk of Alzheimer’s disease," lead author Gawon Cho, a postdoctoral associate at Yale School of Medicine, said in a press release. "These results are particularly significant because they help characterize how sleep deficiency, a prevalent disturbance among middle-aged and older adults, may relate to Alzheimer’s disease pathogenesis and cognitive impairment."
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While deep sleep and REM sleep aren’t the cure for Alzheimer’s disease, prioritizing it may reduce your chances of developing it later on.
"Sleep architecture may be a modifiable risk factor for Alzheimer’s disease and related dementias, posing the opportunity to explore interventions to reduce risk or delay Alzheimer’s onset," explained Cho.
But remember—deep sleep doesn’t just happen, either. You have to get through two sleep cycle stages before entering deep sleep, followed by REM sleep, which means you need plenty of hours of shut-eye. "The more time you are in bed, the more a person sleeps, and generally speaking, the longer a person sleeps, the more REM and deep sleep they will get," explained preventive neurologist Richard Issacson, MD, in a CNN interview.
"How do you make your sleep better? I think people really have to do their part to improve their own sleep," added Cho. "There’s no one medicine that improves overall sleep."
