Roundup: Chronic Delays in Reaching ‘REM Sleep’ May Raise Risk of Alzheimer’s; and More News

REM Sleep Issues Linked to Alzheimer's Risk: What You Need to Know

A new study explores how chronic sleep patterns, specifically the time it takes to enter REM (Rapid Eye Movement) sleep, could raise one’s risk of developing Alzheimer's disease. Scientists have found that a delay in reaching REM sleep may not just disrupt the quality of rest -- but could signal a potential early sign of Alzheimer's — long before memory loss becomes noticeable.

REM is the stage of sleep where the brain is highly active, processing memories, especially emotionally charged ones, and consolidating them into long-term storage. It follows three phases of non-REM sleep, each getting progressively deeper. A complete sleep cycle takes about 90 minutes, and over the course of a night, a healthy adult will cycle through REM sleep four or five times.

But not everyone enters REM sleep at the same speed. As we age, it typically takes longer to reach this stage. However, scientists have now found that people who take significantly longer to reach REM sleep may be experiencing an early warning sign of Alzheimer's.

In this study, researchers monitored 128 people with varying cognitive health, ranging from those with Alzheimer's to those with mild cognitive impairment (a condition often seen as a precursor to Alzheimer's) to healthy individuals. The study, published in Alzheimer’s and Dementia: The Journal of the Alzheimer’s Association, measured brainwave activity, eye movement, heart rate, and breathing patterns of participants as they slept in a clinical setting.

What the researchers discovered was striking: People with Alzheimer’s were more likely to experience a delay in entering REM sleep. On average, it took the delayed group more than 193 minutes to enter REM sleep, compared to just 98 minutes for those in the "early" group. This delay was also linked to higher levels of two toxic proteins—amyloid and tau—both of which are found in higher concentrations in the brains of those with Alzheimer's.

The delay in entering REM sleep appears to interfere with the brain’s ability to consolidate memories, a function that’s critical for learning and long-term memory storage. If REM sleep is insufficient or delayed, it can lead to increased cortisol levels (the stress hormone), which may harm the hippocampus, the brain region responsible for memory consolidation.

Researchers also found that individuals with delayed REM sleep had a 16 percent increase in amyloid levels, a 29 percent increase in tau levels, and a 39 percent decrease in brain-derived neurotrophic factor (BDNF), a protein that is essential for brain health and decreases in Alzheimer's patients.

While more research is needed to understand the full implications of this study, the findings offer a new perspective on how sleep could influence Alzheimer’s risk. Healthy sleep habits are crucial, not just for overall health but potentially for protecting your brain from neurodegenerative diseases.

Researchers suggest that practicing habits that support good sleep, such as addressing conditions like sleep apnea, avoiding alcohol before bed, and maintaining a consistent sleep schedule, may help reduce the risk of Alzheimer's.

If you're concerned about your own sleep patterns or Alzheimer's risk, it’s a good idea to speak with a healthcare provider. They can guide you on improving your sleep hygiene and, if necessary, explore treatments to help maintain healthy REM sleep.

Learn more about Sleep Medicine Services at Baptist Health.

Flossing Your Way to Better Brain Health: A New Study Links Oral Hygiene to Lower Stroke Risk

Flossing is essential for keeping teeth and gums healthy, but a new study finds that it may also play a role in reducing your risk of stroke. The research, presented this week at the American Stroke Association’s International Stroke Conference 2025, suggests that flossing your teeth at least once a week could be linked to a lower risk of stroke caused by blood clots and irregular heartbeats.

The findings, though still in their early stages, indicates that dental and gum care may have far-reaching implications for brain health. The study adds to mounting research about the link between oral hygiene and cardiovascular health.

Researchers analyzed data from the Atherosclerosis Risk in Communities (ARIC) study, which followed more than 6,000 people for over 25 years. The study aimed to explore how various oral hygiene behaviors — flossing, brushing, and regular dentist visits — might influence stroke risk and other heart-related conditions.

Lead researcher Souvik Sen, M.D., who heads the Department of Neurology at Prisma Health Richland Hospital and the University of South Carolina School of Medicine, explained that oral diseases like untreated tooth decay and gum disease are a global health issue, affecting 3.5 billion people. Given the widespread nature of these conditions, it’s crucial to understand whether simple habits like flossing could contribute to preventing major health problems, including stroke, he said.

After analyzing the data, the researchers found several noteworthy correlations:

1. Flossing and Stroke Risk: People who flossed at least once a week had a 22 percent lower risk of ischemic stroke (a type of stroke caused by a blockage in blood flow). They also showed a 44% lower risk of cardioembolic stroke, where blood clots travel from the heart to the brain, and a 12% lower risk of developing atrial fibrillation (AFib), a common irregular heartbeat that can lead to stroke.
2. Frequency Matters: The more often participants flossed, the greater the reduction in stroke risk. Regular flossing seemed to have an even more significant impact when combined with good oral hygiene habits, such as brushing and visiting the dentist regularly.
3. Flossing Reduces Other Oral Health Risks: In addition to stroke prevention, flossing was also linked to a lower chance of cavities and periodontal disease, which are common issues related to poor oral health.

One of the most surprising findings was the connection between flossing and a lower risk of atrial fibrillation (AFib), an irregular heartbeat that affects millions of people worldwide and can increase the likelihood of stroke. This discovery adds an interesting layer to the study, suggesting that flossing may help reduce the chronic inflammation and artery hardening linked to both heart and stroke risks.

AFib is expected to affect over 12 million people in the U.S. by 2030, according to the American Heart Association. By promoting oral health and reducing inflammation, flossing could help mitigate some of these risks—offering a low-cost, accessible way to protect both your heart and your brain.

While these findings are promising, there are some limitations. The data relied on participants’ self-reports of their flossing habits, and there was no follow-up on oral hygiene practices over the 25-year study period.

Could Coffee Help Prevent Cognitive Decline in People with AFib? New Study Suggests It Might

Drinking multiple cups of coffee each day could offer more benefits than previously thought, especially for individuals with atrial fibrillation (AFib), the most common heart rhythm disorder.

A new study published in the Journal of the American Heart Association suggests that coffee may help prevent cognitive decline in people with AFib, challenging long-standing concerns about the negative effects of caffeine for those with irregular heart rhythms.

For years, people with AFib were often advised to limit their intake of caffeinated beverages due to concerns that caffeine could exacerbate heart rhythm issues. However, this new analysis by researchers at the University of Zurich, appears to dispel this myth. “Our study found no reason to discourage or forbid a patient with AFib from drinking coffee,” said senior study author Jürg H. Beer, M.D., in a news released from the American Heart Association. “In fact, it may even be good for you.”

Nonetheless, anyone diagnosed with AFib should consult with the doctor regarding the regular consumption of caffeinated drinks. Previous studies have shown drinking coffee helps cognition in otherwise healthy people.

AFib affects more than 5 million people in the U.S., and those living with the condition are at increased risk for cognitive decline, stroke, and dementia. U.S. guidelines released in 2023 for managing AFib by the American Heart Association, American College of Cardiology, American College of Clinical Pharmacy and the Heart Rhythm Society acknowledge no direct benefit to avoiding coffee.

But they do mention that some individuals with AFib might experience symptom relief if they reduce caffeine due to symptoms like dizziness or fatigue. However, drinking coffee doesn’t seem to pose a risk for most people with AFib, the guidelines concluded.

The new study involved 2,413 participants diagnosed with AFib, with an average age of 73, who took part in the Swiss Atrial Fibrillation Cohort Study. Researchers analyzed cognitive function, inflammation markers, and coffee consumption over a 12-month period. Participants reported their coffee intake, and researchers compared the cognitive scores of those who drank more than five cups a day to those who drank less than one.

The results were striking: People who drank more coffee had significantly better cognitive test scores, particularly in areas like attention, processing speed, and visuomotor coordination. On average, those who consumed five or more cups daily showed a cognitive age that was 6.7 years younger than those who drank less than one cup.

Additionally, participants with higher coffee consumption had inflammatory markers more than 20 percent lower than those who drank less coffee, an encouraging sign since inflammation is linked to both Alzheimer’s disease and AFib.

Massimo Barbagallo, M.D., the study’s lead author, explained that while AFib is known to increase the risk of dementia, coffee might counterbalance this risk. Even after adjusting for factors like age, sex, body mass index, and stroke history, the study’s results remained consistent.

Researchers speculate that the cognitive benefits of coffee may be attributed to its active ingredients, including caffeine, magnesium, and vitamin B3, which are known to have neuroprotective properties. Coffee is also believed to reduce inflammation, which may contribute to its protective effects on brain health.