Can Good Sleep Help Prevent Alzheimer’s Disease and Dementia?

Bad sleep is associated with increased risk for developing dementia. Good sleep is crucial for protecting yourself against memory loss and preserving cognitive function.

While you can’t control your genetic risk for Alzheimer’s disease and dementia, you can lower your risk of developing a memory disorder by improving your sleep, which can greatly improve your health in general, said Sarah Kim, MD, a geriatric psychiatrist at the Jona Goldrich Center for Alzheimer's and Memory Disorders program in the Cedars-Sinai Department of Neurology.  

Anxiety, screen time, and family and work obligations may conspire to steal your sleep, but you can develop strategies to slumber soundly, which can help you remain healthy for longer. Cedars-Sinai experts share their knowledge on the importance of quality sleep, how to know you’ve gotten enough and ways to prioritize rest.

Why Sleep Matters for Brain Health

Each person is different and each night is unique, but the American Academy of Sleep Medicine recommends adults aim for at least seven hours of quality, uninterrupted sleep.

For most people, regularly getting fewer than seven hours of sleep leads to an accumulation of “sleep debt,” said Serghei Burcovschii, MD, a primary care and sleep medicine physician in Tarzana.

Sleep debt is associated with neuroinflammation and a higher risk of conditions such as dementia, depression and cardiovascular disease.

“We live in a very busy, grind-oriented world, and roughly a third of U.S. adults regularly get less than the recommended seven hours of sleep each night,” he said. “But sleep debt is incredibly difficult to pay off, and it’s worse when it becomes chronic.”

Research shows that even one hour of sleep debt in a single night can require four days of adequate sleep for your body to recover. Prioritize getting enough sleep consistently, rather than relying on recovery sleep to make up for sleep loss.

“Sleep is an essential pillar of health, and it is closely linked to many medical and psychiatric conditions,” Burcovschii said. “Often, when sleep improves, people also notice better nutrition, more energy for exercise and improved overall wellbeing. The body’s systems are deeply interconnected.”

What Research Shows About Sleep Disturbance and Dementia Risk

When you sleep, you should cycle in and out of four stages: Light sleep, non-REM stage two sleep, deep or slow-wave sleep, and REM sleep.

The third stage, deep sleep, is the most restorative stage, and critical for cognitive function, said Kim. More research is needed to determine whether more slow-wave sleep can prevent Alzheimer’s, but studies show that especially during deep sleep, cerebral spinal fluid circulates through the brain to “wash away” neurotoxic proteins and plaques implicated in Alzheimer’s and dementia. During deep sleep, the brain clears double the protein it does while you’re awake.

How Can You Know If You Get Enough Deep Sleep?

The best indicator of sleep quality is the way you feel when you wake up. After a night of adequate deep sleep, you should feel rested and restored.

Wearable sleep monitors like rings and watches are mostly accurate for measuring sleep duration, Kim said. However, the data they provide about sleep phases is not validated. Tracking your sleep with a device can be counterproductive if it supersedes your awareness: An overdependence on wearables can disconnect you from your body, and the obsession can even induce insomnia.

“When evaluating your sleep quality, focus more on your experience than on the numbers your phone feeds you,” Kim said.

She suggests a low-fi alternative, like a physical journal, to help improve sleep. Record the time you went to bed, how easy it was to fall asleep and the time you woke up, which can help you connect your sleep quality to factors in your day or life.

Practical Strategies to Improve Sleep and Protect Brain Health

Kim and Burcovschii offered the following tips to make the most of your time in bed, improve your health and maintain your memory.

Clean Up Your Sleep Routine

You’ve heard it before because it actually works: Keep your bedroom cool and dark and use it only for sleep and sex consistent sleep schedule; and don’t bring your phone to bed. Kim also suggests patients follow the 10-3-2-1 rule for sleep hygiene:  

• Avoid caffeine for at least 10 hours before bedtime

• Stop eating or drinking for at least three hours before you sleep

• Finish heavy exercise at least two hours before sleep

• Turn off all screens at least an hour before bed

Rule Out Sleep Apnea and Other Conditions

Obstructive sleep apnea is a condition in which the airway partially or completely collapses during sleep, which causes people to stop breathing and disrupts the sleep cycle. In the United States, at least 80% of moderate to severe obstructive sleep apnea is undiagnosed.

If untreated, sleep apnea can cause frequent awakenings, which can lead to excessive daytime sleepiness. It also causes repeated drops in oxygen levels, which is especially harmful to the heart and brain. Severe sleep apnea increases a person’s risk for stroke, heart attack and accidents caused by drowsiness, Burcovschii said.

If you’re getting enough hours of sleep, but you still wake up tired—or if your bed partner notices loud snoring or pauses in your breathing—tell your doctor. A simple at-home test worn overnight can diagnose most cases of sleep apnea.

Positive airway pressure (PAP) therapy, commonly known as CPAP, is the gold standard to treat sleep apnea. The device delivers gentle air pressure through a mask to keep your airway open while you sleep. Many people worry about using a CPAP, but new devices are smaller, quieter and more comfortable than older models.

“Getting used to wearing the CPAP can be a big challenge, especially during the first two weeks,” Burcovschii said. “But luckily, there are many devices to choose from.”

Genetics and medical conditions might contribute to sleeplessness, but don’t assume that you must accept poor sleep. Discuss your concerns with your doctor.

Try Cognitive Behavioral Sleep Therapy for Insomnia

Although physicians sometimes prescribe sleeping pills for short-term insomnia relief, these medications can actually worsen conditions related to sleep. They can cause daytime drowsiness, memory problems and risk of dependence.

Some studies suggest sedatives can contribute to the progression of dementia. Guidelines recommend cognitive behavioral therapy for insomnia (CBT-I) before taking even over-the-counter medications or supplements.

“This behavioral approach is overlooked and underused, partially because of a lack of access,” Burcovschii said.

Cedars-Sinai physicians can refer patients to virtual CBT-I, which can help patients identify and change thoughts and behaviors that interfere with good sleep.

Find Your Chronotype

Everyone has a natural tendency to either wake up early or stay up late. This preference—called your chronotype—is influenced by your genes, your age and your environment. Your brain has an internal “master clock” that helps regulate this timing.

You can identify your chronotype by tracking your sleep patterns for one or two weeks. Record when you naturally get tired and when you wake up without an alarm. Note when you feel most alert and energic throughout the day, and try to let that guide you in establishing a sleep routine.

“Some people are genetically inclined to feel sleepy later at night, and forcing yourself to bed before you’re tired can backfire,” Burcovschii said. “Find a consistent sleep schedule that respects your natural tendencies while still prioritizing earlier bedtimes when possible.”

Take Power Naps

Short daytime naps are OK, if they’re less than 30 minutes, Kim said.

“A quick rest can replenish your energy so you can stay active the rest of the day and sleep better at night,” she said.

The Bottom Line

Sleep cannot eliminate your risk for developing a memory disorder, but prioritizing your sleep can help protect your long-term memory.

“Do whatever it takes to control your environment—manage your pet or your bedmate and get blackout curtains or a white noise machine,” Kim said.

Sometimes it makes sense to sacrifice a little sleep for events or activities which bring you joy, and some nights you’ll sleep better than others, naturally.

“Of course, we live in the real world of social obligations, kids and illness. Unfortunately, all of these factors impact sleep quality,” Burcovschii said. “But this cannot become chronic, and you have to recognize the importance of sleep and do your best to optimize it.”