New Alzheimer’s Warning Sign Discovered by Scientists—and It Has to Do With Your Sleep
Despite years of research, scientists are still trying to understand why some people develop Alzheimer’s disease while others do not. Now, new evidence indicates that our sleep patterns—particularly how quickly we enter Rapid Eye Movement (REM) sleep—could be a key piece of the puzzle.
REM is the stage of sleep when brain activity increases, breathing becomes irregular, the eyes move quickly, and dreams occur. REM sleep typically occurs about 90 minutes after falling asleep and repeats several times throughout the night.
This stage is key to processing memories and emotions, as well as consolidating information into long-term memory.
The study, published in Alzheimer’s and Dementia, The Journal of the Alzheimer’s Association, suggests that a slow start to the first REM period after going to sleep may be an early symptom of the disease.
“The delay in REM sleep disrupts the brain’s ability to consolidate memories by interfering with the process that contributes to learning and memory,” Yue Leng, the study’s co-senior author and an associate professor in the Department of Psychiatry and Behavioral Sciences at the University of California, San Francisco (UCSF), said in a press release. “If it is insufficient or delayed, it may increase the stress hormone cortisol. This can impair the brain’s hippocampus, a critical structure for memory consolidation.”
Alzheimer’s is a destructive neurodegenerative disease that slowly damages memory, thinking, reasoning, and other cognitive functions. Alzheimer’s disease, which is the most common form of dementia, affects more than seven million adults in the United States, according to the Alzheimer’s Association.
Highlights From the Study
The study involved 128 people with an average age of 70 from the neurology unit of the China-Japan Friendship Hospital in Beijing, China. Of the participants, 64 had Alzheimer’s disease, 41 had mild cognitive impairment, and 23 had normal cognitive function.
The participants spent the night in the clinic, and researchers measured their brainwave activity, eye movements, heart rate, and breathing. They were also scanned for biomarkers that indicated Alzheimer’s disease.
The investigators wanted to determine how long it took the participants to reach REM sleep for the first time after falling asleep.
The participants were divided into early and delayed REM sleep groups. The early group reached the REM stage less than 98 minutes after falling asleep, whereas the late group took more than 193 minutes to reach the REM stage after falling asleep.
Researchers also discovered that participants with Alzheimer’s disease were more likely to have delayed REM sleep. They also showed higher levels of amyloid and tau, two main proteins that scientists believe interfere with communication between brain cells and contribute to Alzheimer’s disease and other dementias.
Additionally, participants with delayed REM sleep had 16 percent more amyloid and 29 percent more tau than those with early REM sleep. They also had 39 percent less Brain-Derived Neurotrophic Factor (BDNF), a protein crucial for brain health that helps neurons survive and grow. BDNF decreases in individuals with Alzheimer’s disease.
Researchers acknowledge that their study had some limitations. For one, the study was “cross-sectional,” meaning information was collected at a single point in time. As a result, the investigators said they could not determine whether delayed REM sleep causes Alzheimer’s or if the disease’s progression causes altered sleep patterns.
Also, the researchers noted that monitoring sleep in a clinical setting may introduce “environmental disturbances,” impacting sleep measurement accuracy. “Future studies will benefit from research in real-world home settings,” they wrote.
Furthermore, the investigators noted that the sample size in each diagnosis group was relatively small. Additionally, they only examined one specific type of protein.
Sleep Experts React to the Study’s Findings
Despite the limitations, Dr. Wendy Troxel, a senior behavioral scientist at the RAND Corporation in California, stated that this study contributes to the “growing evidence” linking REM sleep and other specific sleep features to Alzheimer’s biomarkers.
Troxel has also been involved in sleep-related research, which shows a connection between poor sleep and declining cognitive function.
“Sleep disruptions may contribute to the buildup of amyloid and tau proteins, key features of Alzheimer’s pathology,” Dr. Troxel told Fox News Digital. “But it’s also important to note that the Alzheimer’s disease process itself can disrupt sleep, suggesting a bidirectional association between sleep problems and cognitive decline.”
Just as it’s been “long understood” that a good night’s sleep is linked to a lower risk of developing dementia, the study offers a “promising avenue” for predicting the chance that someone will eventually develop dementia, according to Dr. Giulio Taglialatela, vice president and research institute director of the Brain Health Institute at the University of Texas Medical Branch.
“Early intervention in Alzheimer’s is essential for delaying its progression, and measuring REM sleep could be a marker to indicate who may be a candidate for treatment even before they start to show impaired cognitive function,” Dr. Taglialatela told Fox News Digital.
Dr. Taglialatela explained that our brains use sleep to clear out toxic proteins, like those associated with Alzheimer’s. The study’s results show that the cleaning mechanism is less effective when it takes someone longer to enter the REM cycle. “Unfortunately, there is nothing an individual can do to control how long it takes to enter REM sleep,” he said.
Tips for Getting More REM Sleep
On average, most people go through four to six sleep cycles each night, including the REM (rapid eye movement) sleep stage. Sleep experts say that you cannot control the stages of sleep you go through or when they occur, but you can focus on getting good sleep.
Dr. W. Christopher Winter, a neurologist and sleep medicine physician with Charlottesville Neurology and Sleep Medicine and host of the Sleep Unplugged podcast, offers the following ways to support good sleep:
Establish a consistent bedtime and wake time, and try your best to adhere to them.
- • Limit your alcohol and caffeine consumption, especially avoiding caffeine in the late afternoon or evening.
- • Make an effort to be physically active, and try to exercise in the mornings to support your body’s natural sleep-wake cycle.
- • Establish a good, consistent bedtime routine that helps you wind down in the evening.
- • Be cautious with sleep aids. “Ironically, some sleep aids affect REM sleep,” Winter said.
Dr. Dantao Peng, the study’s co-senior author and a neurologist with the Department of Neurology at the China-Japan Friendship Hospital in Beijing, recommends treating conditions like sleep apnea and “avoiding heavy drinking,” both of which can interfere with a healthy sleep cycle.
If you’re having trouble sleeping, Winter advises seeing a healthcare professional sooner rather than later. A sleep study may be recommended to provide more information about the cause of your sleep problems. The healthcare professional will make personalized recommendations based on the results, he said.
Source Links:
https://www.yahoo.com/news/scientists-discovered-alzheimers-warning-sign-140000737.html
https://www.ucsf.edu/news/2025/01/429346/delayed-rem-sleep-could-be-early-sign-alzheimers
https://www.foxnews.com/health/alzheimers-risk-could-rise-specific-sleep-pattern-experts-warn
https://www.alz.org/alzheimers-dementia/facts-figures
