More than cancer, heart disease or even COVID-19, Alzheimer’s is among the diseases feared most by older Americans. The only disease among the top 10 causes of death in the U.S. with no known cure, Alzheimer’s is more deadly than breast cancer and prostate cancer combined.

In the U.S. alone, more than 6 million people are living with Alzheimers, the most common cause of dementia, according to the Alzheimer’s Association. Other forms include vascular dementia, Lewy body dementia and mixed dementia — a common situation in which people have two or more types of dementia at once.

These dreaded diseases not only rob people of their language skills, cognitive abilities, memory and physical health. They also take a tremendous financial and emotional toll on patients’ families, caregivers, loved ones and the greater community.

However, researchers are learning more about the potential causes — and possible ways of slowing or preventing the onset — of dementia.

Sleep and dementia

Recently, a study published in the journal Nature Communications showed a link between sleep duration and the likelihood of developing dementia.

“This was a large study, observing about 8,000 participants in Britain from age 50 through their 70s,” said Novant Health sleep specialist Dr. Nancy Behrens.

Dr. Nancy Behrens

“The researchers found that people who slept less than or equal to six hours a night in their 50s, 60s and 70s had a 30% greater risk of developing dementia decades later,” she said.

The study also showed that, in people with dementia, the disease had been developing over the course of 20 or more years. This knowledge can be used to determine how people’s lifestyles and habits affect how they age and may help guide people in making changes to protect their brains and overall health.

Although the British study didn’t prove beyond a doubt that limited sleep causes Alzheimer’s and other forms of dementia, it did provide solid evidence that getting enough sleep in midlife decreases the risk of developing this dreaded disease, Behrens said.

How much sleep is enough?

To feel well rested and ensure their best performance, adults need to get seven to eight hours of sleep each night, Behrens said.

“I've been in practice for about 15 years, and I have seen some patients who have sleep issues develop dementia,” Behrens said. “I have a lot of patients who just don't devote enough time for sleep, and that does concern me. Chronically limiting sleep can take its toll on your brain as you get older.”

Sleep also plays a key role in helping people feel their best and live healthy lives. It can even help prevent serious chronic illnesses like diabetes, high blood pressure and cardiovascular disease.

Of course, the demands of work, family and illnesses can affect sleep, as can conditions like sleep apnea and restless leg syndrome. But when people choose work, screen time or other distractions over sleep, that’s when Behrens worries.

“We know getting enough sleep really affects how you function day to day,” she said. “And with this study, we’re looking at how limiting your sleep could affect you in the long term, too.”

Some people naturally fall into the group Behrens calls “short sleepers.” They wake feeling refreshed after six hours or so. How do you know if you’re among this minority?

“Really, it’s about how rested you feel without requiring substances to keep you awake,” Behrens said. “You shouldn’t need a lot of caffeine or other stimulants to help you function.”

Others seem to need nine hours a night to feel refreshed. Oversleeping can also leave you groggy and may be a sign of undiagnosed health issues like depression or sleep apnea.

Trouble sleeping

Sleep problems can arise from childhood on. While people do seem to naturally sleep less as they age, the risk of developing sleep apnea, restless leg syndrome or other health-related sleep issues also increases with the years.

“If someone isn’t getting much sleep and feels tired,” Behrens said, “the first thing to do is look at is what they can do to help themselves sleep better.” (For ideas, see the tips below.)

“But if a person with a healthy lifestyle and good sleep habits has trouble sleeping, or doesn’t feel refreshed, that would be a good time to talk with a doctor.”

A doctor can review sleep habits, look for symptoms of other sleep issues and may order a sleep study to get more information about the patient’s sleep and breathing. They may also refer patients to sleep specialists for further treatment.

6 steps to better sleep

We all “have the power to help prevent dementia and other sleep-related illnesses by taking action for ourselves,” Behrens said. “I would like people to really value their sleep, to make the choice to take care of themselves.”

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Act now

Behrens offered the following tips:

  1. Maintain a consistent sleep schedule, even on the weekends. Go to bed around the same time each night, and get up around the same time every morning. Creating a ritual, like taking a warm shower before bed, can help signal to your body that it’s time to unwind and prepare for sleep.
  1. Keep your body in sync with natural cycles of light and dark by heading outside for some exercise, especially in the morning. A study in the Journal of Aging and Health showed that older adults who spent time outdoors experienced fewer sleep difficulties.
  1. Make sure your bedroom is dark, relaxing, cool and quiet. Eliminate as much clutter as possible, and make sure your mattress and pillows are comfortable. If noisy neighbors or other sounds keep you awake, try wearing earplugs or buy a white-noise machine.
  1. Remove all electronic devices, such as TVs and cell phones, from the bedroom. Blue light, even from a tiny cell phone screen, looks like sunlight to our brains, so they don't wind down and produce melatonin as they're supposed to when it gets dark outside.
  1. Eat a light snack if you’re hungry, but avoid eating large or heavy meals within two hours of bedtime. Other sleep disruptors to limit: caffeine, alcohol and nicotine.
  1. Take time to relax before bed. Stepping away from screens and other distractions can help slow a racing mind. Instead, try to spend some quiet time alone. Activities like meditating, reading (not on a screen), knitting, journaling or light stretching can help calm your body and mind.