Delayed REM sleep may be linked to a higher risk of Alzheimer’s disease, new research found

Delayed Dreaming Could Be Associated with Alzheimer’s Disease, New Research Finds Here's how to build a healthy sleep routine

Delayed REM sleep may be linked to a higher risk of Alzheimer’s disease, new research found

• Taking longer to fall into REM—the dream stage of sleep—is linked to a higher risk of Alzheimer’s disease, a new study found.
• REM sleep is essential for learning and memory, and a delay may disrupt this process, researchers suggested, but more research is needed.
• To increase your chances of getting into REM on time, experts recommended establishing a healthy overall sleep routine.

How long it takes for you to start the dream stage of sleep could be connected to your risk of certain cognitive issues, according to a new study.

The research, published on Jan. 27 in Alzheimer’s & Dementia, found that people had a higher risk of Alzheimer’s disease if it took them longer to fall into rapid eye movement (REM) sleep. During this stage of sleep, people have their most vivid dreams, and some memory processing occurs.

These new findings provide more clues about how poor sleep and cognitive decline are related, said Jocelyn Cheng, MD, neurologist and senior director of neuroscience clinical research at pharmaceutical firm Eisai U.S.

“Studies [have shown] that adequate REM is associated with healthy measures of structural integrity and network connectivity in the brain,” Cheng told Health. This study adds to the conversation by showing that there’s also some link between how a person sleeps and changes in the brain indicative of Alzheimer’s, she said.

Here’s what experts had to say about the new study, how REM sleep and Alzheimer’s could be connected, and ways to increase your chances of getting healthy sleep.

How REM Sleep and Alzheimer’s May Be Related

“REM is one of the four stages of sleep that we cycle through during the night, characterized by rapid eye movements and reduction in muscle tone,” Cheng explained. “It typically occurs near the end of the first of several sleep cycles—so about 90 minutes into sleep—and increases in duration as the night progresses.”

With the long-reported connection between Alzheimer’s disease and sleep issues, the authors of this latest study wanted to investigate whether changes to this typical REM timing could be playing a role, too.

Researchers looked at data from 128 people at the China-Japan Friendship Hospital in Beijing. The average age of the participants was about 71, and half had been diagnosed with Alzheimer’s. About a third had a common precursor to Alzheimer’s, mild cognitive impairment (MCI), and the rest of the participants had normal cognition.

The researchers monitored the participants’ sleep in an overnight study, measuring their brainwave activity, heart rate, and more. They were placed into two groups—it took the early group about 98 minutes to start their first REM cycle, while it took the late group about 193 minutes.

After examining the data, researchers found that participants with Alzheimer’s had a higher likelihood of having delayed REM sleep. Participants in this late REM group also tended to have higher levels of amyloid and tau, two proteins associated with Alzheimer’s, and lower levels of brain-derived neurotrophic factor (BDNF), a healthy protein that is reduced among Alzheimer’s patients.

Despite the strong association between delayed REM and Alzheimer’s, it’s not yet clear whether this poor sleep is worsening Alzheimer’s symptoms or if pre-existing cognition issues are disrupting REM sleep.

“The relationship may be bidirectional,” Cheng said. “Delayed REM may contribute to Alzheimer’s-type changes, and/or Alzheimer’s itself may result in prolonged REM latency.”

However, the study’s authors believe issues with memory processing could be one explanation for what’s going on.

“The delay in REM sleep disrupts the brain’s ability to consolidate memories by interfering with the process that contributes to learning and memory,” senior study author Yue Leng, PhD, associate professor of psychiatry and behavioral sciences at UCSF, said in a press release.

For now, though, more research needs to be done to determine how exactly the two are related, Cheng emphasized.

Boosting REM By Establishing Good Sleep Habits

There are plenty of unanswered questions when it comes to cognition and sleep health. And more research needs to be done to confirm that delayed REM onset is actually connected to Alzheimer's in larger and more diverse populations, said Dylan Wint, MD, director of the Cleveland Clinic Lou Ruvo Center for Brain Health.

However, it’s clear that getting little REM sleep isn’t healthy, even if “we still haven’t figured out everything that sleep is for,” Wint told Health. “Sleep is not just rest....There are important physiologic processes that occur during sleep and only during sleep.”

Certain changes in REM are to be expected over the course of a person’s life. “On average, REM sleep comprises about 25% of adult total sleep time, so if an individual gets eight hours of sleep per night, that translates to two hours of REM sleep,” said Cheng. “However, this changes with age. For example, in later or older adulthood, we see a reduction in REM.”

Even antidepressant medications or the temperature of your room can affect when you fall into REM sleep or how much you get.

But because “delayed [or] reduced REM may be associated with Alzheimer‘s-related pathological changes,” it’s important to speak with a doctor if you suspect you’re not getting enough, said Cheng.

A sleep tracker can help you determine this—some popular wearable devices can generate reports that tell people whether they’re getting enough of certain phases of sleep.

However, Cheng advised that people shouldn’t necessarily put too much stock in these trackers, as “their validity is not well-vetted.” They could even raise the risk of orthosomnia, where people develop a “preoccupation with getting ‘perfect’ sleep,” she said.

More simply, if you’re noticing that you suddenly need more sleep than usual, or “if you generally notice that sleep is not refreshing or have other concerning symptoms—[for instance,] someone witnessed that you have pauses in breathing during sleep—then yes, you should talk to a healthcare provider,” Cheng recommended.

To increase your chances of getting into REM in a timely manner—or to increase the amount of REM you’re getting—it’s best to focus on establishing a healthy sleep routine overall.

That includes keeping a consistent bedtime and wake time, turning off electronic devices 30 minutes before bed, and avoiding alcohol and large meals at night, according to the Centers for Disease Control and Prevention (CDC).

“Rather than focusing on one stage of sleep, people should try to increase their ability to obtain a healthy amount of sleep for their age,” Cheng said. “Engaging in healthy sleep habits will help to promote sufficient, good quality sleep, which should, in turn, enable an individual to cycle through all sleep stages adequately.”

Julia is a news reporter and editor for Health, where she covers breaking and trending news on health and wellness topics. Her work has been featured in The Heights, an independent student newspaper at Boston College, and Minnesota Monthly.

This story originally appeared on: Health News - Author:Maggie O'Neill