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Monday, June 29, 2020

Sleep and Alzheimer’s Linked

New studies show a relationship between Alzheimer’s disease and a lack of deep sleep. Nap habits are a key.

Decades before an Alzheimer’s diagnosis is made, those likely to get the disease show disruptions in sleep patterns, in particular, a lack of deep sleep. So says Ruth Benca, a psychiatrist at the University of California Irvine. Her work has followed the parallels between rapid-eye movement (REM) sleep and the development of Alzheimer’s. Now, researchers at Washington University School of Medicine in St. Louis have found that people who have less slow-wave sleep also have higher levels of the brain protein tau, an indicator for Alzheimer’s. 

Track Your Sleep

Both Fitbit and the Apple Watch can help monitor your sleep habits. However, the battery life of Ionic, Versa and Charge 3 Fitbits can be measured in days, not hours, encouraging users to wear it at night, encouraging sleep tracking. “Our typical user is viewing sleep as being really important to their general wellness and mental health and how they handle stress and fatigue,” says Dr. Conor Heneghan, head of innovation and research at Fitbit

Not that the Apple Watch isn’t a stellar health device. It can track sleep by using the heart rate monitor, but its 18-hour battery life means you need to take it off to charge it up. It also requires a third-party app to download data so that users can visualize the results. Fitbit sleep tracking is built into the device, just like step tracking, and you don’t have to set up or install anything additional. 

“We’re very interested in using the sleep tracking to then provide an additional service to alert people to a sleep apnea risk,” Heneghan said. “That’s where the battery life is important, because if you’re charging your device, you can’t be screening or detecting your sleep problems.” 

One way to avoid battery issues is to get a device specifically for sleep. The Oura ring slides on a finger at night and measures REM sleep, deep sleep, restlessness and other factors. However, some might be discouraged by its $299 and up price tag on a device that only measures sleep habits. 

Another downside to sleep tracking is that anxiety over results may actually make your sleep worse, not better. And while you may learn that sleep worsens after a glass or two of wine and improves on days you exercised, what do you do with the rest of the data? Experts recommend writing down your mood when you awaken, but before taking a look at device results, to better assess how your night’s rest has made you feel.

Sleep Adaptogens: Botanicals To Relieve Stress 

Adaptogens have long been used in Chinese medicine to help “balance” the body. They have to meet three criteria: 

  1. They must be nonspecific and assist the body in a range of adverse conditions (physical, chemical and/or biological stress).
  2. They must offset or resist physical disorders caused by external stress. 
  3. They must not harm the normal functions of the body. 

"The stress hormone, called cortisol, is our primary fight-or-flight hormone, and its release triggers an adrenal response causing physiological changes such as spikes in heart rate, blood pressure, and blood sugar,” according to Steven Zen, founder and CEO of Lokai, which has a line of adaptogen tonics. A spike in cortisol can lead to sleep disruption.

Some of the better-known adaptogens for sleep include ashwagandaha, prized in Ayurvedic medicine for its healing power, and Holy Basil, which is thought to bestow tranquility. They are available in tablets, teas and more. 

It’s long been known that people with Alzheimer’s tend to have poor sleep. But scientists now think that that a lack of deep sleep may be a sign of the disease that appears long before cognitive symptoms are apparent.

"What's interesting is that we saw this inverse relationship between decreased slow-wave sleep and more tau protein in people who were either cognitively normal or very mildly impaired, meaning that reduced slow-wave activity may be a marker for the transition between normal and impaired," said first author Brendan Lucey, MD, an assistant professor of neurology and director of the Washington University Sleep Medicine Center. "Measuring how people sleep may be a noninvasive way to screen for Alzheimer's disease before or just as people begin to develop problems with memory and thinking.”

Studies show that amyloid beta protein starts to build plaque in the brain well before memory loss and confusion are evident. Tangles of tau appear after the plaque, but in advance of brain atrophy. While there is currently no cure for the disease, there are medicines that can slow its progression if it is discovered early. 


"The key is that it wasn't the total amount of sleep that was linked to tau, it was the slow-wave sleep, which reflects quality of sleep," says Lucey. "The people with increased tau pathology were actually sleeping more at night and napping more in the day, but they weren't getting as good quality sleep.” 

In fact, daytime resting in itself was “significantly” tied to high tau levels, meaning that nappers might want to seek further testing. But nap habits alone, or even impaired sleep, don’t mean you’ll get Alzheimer’s.

"I don't expect sleep monitoring to replace brain scans or cerebrospinal fluid analysis for identifying early signs of Alzheimer's disease, but it could supplement them," Lucey said. "It's something that could be easily followed over time, and if someone's sleep habits start changing, that could be a sign for doctors to take a closer look at what might be going on in their brains."

The Chicken or the Egg?

One thing that researchers don’t yet understand is if poor sleep is allowing buildups of amyloid and tau, or if amyloid and tau deposits inhibit deep sleep. However, healthy research subjects who consented to being awakened every hour (!) showed increased levels of amyloid the day after in a study from the National Institutes of Health in Bethesda, Maryland.

While none of us is likely to get a good night’s sleep every time we lay our head on a pillow, it’s worth the effort. Aim for seven hours. Think of it like you do other health initiatives — getting enough exercise, eating well, keeping alcohol consumption moderate, and not smoking. You may not always meet your goals, but aiming for them is a good thing in itself.


Blog posting provided by Society of Certified Senior Advisors