Alzheimer’s and Sleep: Can Poor Sleep Increase Your Risk?

Quick answer: Regularly sleeping too little or waking often during the night has been linked to a higher risk of dementia and Alzheimer’s-related brain changes. Poor sleep has not been proven to cause Alzheimer’s disease, and early changes from the disease may also begin affecting sleep.

About 1 in 9 Americans age 65 and older is living with dementia caused by Alzheimer’s disease [1]. If you regularly sleep too little or wake often during the night, you may wonder what that could mean for your brain.

Studies have found a connection between long-term sleep problems and Alzheimer’s-related changes. The relationship may also work in reverse, since the disease can begin affecting sleep before memory symptoms appear.

The good news is that many sleep problems have causes that can be identified and treated. Understanding the connection can help you know what to watch for and when to seek help.

What sleep problems have been linked to Alzheimer’s?

Researchers have studied several sleep patterns, including:

• Regularly sleeping six hours or less

• Waking many times during the night

• Having ongoing insomnia

• Following an irregular sleep schedule

• Having untreated sleep apnea

• Getting less deep or REM sleep

Having one of these sleep problems does not mean that you will develop Alzheimer’s. Most research looks at patterns that continue over time, not an occasional restless night.

Sleeping too little

One long-running study followed nearly 8,000 adults for about 25 years. People who regularly slept six hours or less at ages 50 and 60 were more likely to develop dementia than those who slept seven hours [2].

The study looked at dementia overall rather than Alzheimer’s alone. It found a connection, but it could not show that short sleep caused the later diagnoses.

The number of hours is not the only concern. Seven or eight hours in bed may still leave you tired when much of that time is spent awake.

Broken sleep and insomnia

You may have broken sleep if you wake often, stay awake for long periods, or keep drifting in and out of light sleep.

Insomnia can look different from one person to another. You might:

• Take a long time to fall asleep

• Wake several times throughout the night

• Wake much earlier than planned

• Feel tired even after getting enough sleep

Stress, depression, pain, menopause, reflux, medications, and other sleep disorders can all contribute. Many of these causes can be treated.

Sleep apnea

Obstructive sleep apnea causes breathing to stop or become shallow repeatedly during sleep. These interruptions can pull you out of deeper sleep and cause oxygen levels to drop.

A review of 15 long-term studies found that people with sleep apnea had a higher risk of cognitive impairment or dementia [3]. The connection was weaker in studies that confirmed sleep apnea with overnight testing, so the exact size of the risk remains uncertain.

Possible signs of sleep apnea include:

• Loud, regular snoring

• Gasping or choking during sleep

• Pauses in breathing noticed by someone else

• Morning headaches

• Dry mouth after waking

• Feeling very sleepy during the day

• Trouble concentrating

Sleep apnea can be treated. Speak with a healthcare professional if you recognize these symptoms, whether or not you are concerned about Alzheimer’s.

Also Read: Why Sleep Deprivation Can Lead to Serious Health Issues

Why might poor sleep affect the brain?

Your brain stays active while you sleep. It organizes memories, moves through different sleep stages, and changes how certain proteins are produced and cleared.

Scientists are studying how these processes may connect sleep with Alzheimer’s disease.

Amyloid-beta and tau

Amyloid-beta and tau are two proteins involved in Alzheimer’s. Amyloid-beta can collect between brain cells and form plaques [4]. Abnormal tau can build up inside cells and form tangles. Both can interfere with how brain cells work.

A 2025 review looked at 30 studies involving nearly 15,000 adults who did not have dementia. Poorer sleep quality and shorter sleep were linked with a greater amount of amyloid-beta seen on PET brain scans [5]. The review did not find a consistent connection between sleep and tau.

Scientists have also studied what happens after a night without sleep. In one small study, 20 healthy adults had brain scans after sleeping normally and after staying awake all night. Amyloid-beta measurements increased in two brain areas following the sleepless night [6].

One night of poor sleep does not cause Alzheimer’s. The study shows that sleep loss can affect amyloid-beta levels over a short period, while Alzheimer’s disease develops over many years.

Deep sleep and REM sleep

You move through several stages of sleep during the night.

Deep sleep, also called slow-wave sleep, supports memory and physical recovery. REM sleep plays a role in learning, memory, and emotional processing.

A 2025 study compared the sleep records of 270 adults with brain scans taken 13 to 17 years later. People who had spent less of the night in deep and REM sleep had less volume in a brain region that can be affected by Alzheimer’s disease. The study found a connection, but it could not show that reduced deep or REM sleep caused the later brain changes [7].

A smartwatch or sleep tracker cannot tell you whether you are at risk of Alzheimer’s. These devices estimate sleep stages and are not as precise as an overnight sleep study.

The brain’s waste-clearance system

You may have read that sleep “cleans” or “detoxes” the brain. This idea refers partly to the glymphatic system, which helps move fluid and waste products through brain tissue.

Scientists are studying whether this movement helps the brain handle amyloid-beta, tau, and other substances. Sleep appears to affect the process, but much of the detailed evidence comes from animal studies.

Researchers do not yet have a standard way to measure glymphatic activity in a living person. They also have not shown that problems with this system directly cause Alzheimer’s disease [8].

The glymphatic system may help explain some of the connection between sleep and brain health. But saying that sleep “flushes out Alzheimer’s toxins” goes further than the research supports.

Can Alzheimer’s begin changing your sleep?

Yes. Alzheimer’s itself can affect sleep. The disease can interfere with areas of the brain that regulate the body clock. This may make it harder to stay alert during the day and sleep through the night.

Early Alzheimer’s-related changes may also begin years before clear problems with memory or thinking. In one study, older adults with biological signs of early Alzheimer’s had more disrupted patterns of rest and activity, even though they did not have noticeable memory symptoms [9].

This is one reason the relationship between Alzheimer’s and sleep is difficult to separate. Long-term sleep problems may affect brain health, while early changes in the disease may already be making sleep less regular.

Sleep changes by themselves cannot diagnose Alzheimer’s. Insomnia, sleep apnea, stress, depression, pain, medications, menopause, and normal aging can cause similar patterns.

What sleep changes can happen with Alzheimer’s?

Sleep problems often become more noticeable as Alzheimer’s progresses.

You might notice that a loved one:

• Sleeps much more or less than before

• Takes frequent naps during the day

• Has trouble falling asleep at night

• Wakes many times and struggles to settle again

• Becomes active during the night

• Confuses daytime with nighttime

• Feels restless or agitated in the evening

Restlessness, confusion, or agitation that begins later in the day is often called sundowning. Some people may pace or wander during the night.

Alzheimer’s may not be the only reason for the change. Pain, hunger, thirst, constipation, depression, restless legs syndrome, sleep apnea, medications, and an uncomfortable room may also disturb sleep.

A sudden change can sometimes point to an infection, medication side effect, or another health problem. Let the person’s healthcare team know when the change is new or severe.

Also Read: This Common Habit Makes Insomnia Worse

How much sleep should you get?

Most adults, including older adults, generally need about 7 to 9 hours each night.

No specific number of hours has been proven to prevent Alzheimer’s disease. Sleep needs also vary, and some people feel well after 7 hours, while others need closer to 9.

How you sleep matters too. Consider whether you:

• Wake feeling rested

• Stay asleep for most of the night

• Feel alert during the day

• Keep a fairly regular sleep schedule

• Breathe comfortably while sleeping

Sleeping longer is not always better. An increase in sleep may come from broken nighttime sleep, depression, medications, sleep apnea, illness, or another change in health.

Also Read: Sleep Quantity vs Sleep Quality: Which One Do You Actually Need?

What can you do about poor sleep?

You may need to try more than one change before you notice a difference.

Keep a steady schedule

Try to wake up and go to bed at similar times each day. Big changes between weekdays and weekends can make your body clock less predictable.

Get daylight after waking

Morning light helps your body recognize when the day has started. Spending time outdoors may also help you feel more alert during the day.

Move during the day

Walking and other regular physical activity may make sleep easier at night. Choose a time that does not leave you feeling too alert near bedtime.

Review your caffeine

Coffee, tea, energy drinks, chocolate, workout products, and some medicines contain caffeine. Try reducing the amount or having your final serving earlier in the day.

Limit alcohol near bedtime

Alcohol may make you sleepy at first, but it can lead to more waking later in the night. It can also worsen snoring and sleep apnea.

Look for what keeps waking you

Pain, reflux, frequent urination, noise, room temperature, and medication effects can interrupt sleep. Addressing the source may help more than adding extra steps to your bedtime routine.

Get checked for sleep apnea

Loud snoring, gasping, breathing pauses, morning headaches, and severe daytime sleepiness are reasons to speak with a healthcare professional.

Ask for help with ongoing insomnia

Insomnia can often be treated. A doctor may review your health and medications or recommend cognitive behavioral therapy for insomnia.

Improving sleep can help your mood, concentration, energy, and daily quality of life. 

When should you talk to a doctor?

Consider getting medical advice when:

• Sleep problems continue for several weeks

• Poor sleep affects your work, driving, mood, or daily activities

• You regularly feel sleepy despite spending enough time in bed

• You snore loudly, gasp, or stop breathing during sleep

• You begin sleeping much more or less than usual

• Sleep changes happen alongside new memory or thinking problems

• A person with Alzheimer’s develops new confusion, agitation, or wandering at night

A doctor can look for sleep apnea, insomnia, medication effects, pain, depression, infection, and other possible causes.

Alzheimer’s and sleep FAQs

Can one night of poor sleep cause Alzheimer’s?

No. A sleepless night may temporarily affect memory, concentration, and amyloid-beta measurements, but it does not cause Alzheimer’s disease.

Can sleeping too little cause early dementia?

Regularly sleeping too little has been linked to a higher risk of dementia. Research has not shown that it directly causes early dementia, and early brain changes may sometimes affect sleep before other symptoms appear.

Is sleeping too much a sign of Alzheimer’s?

Sleeping more can happen with Alzheimer’s, but it also has many other causes. These include poor sleep at night, depression, medications, sleep apnea, illness, and low daytime activity.

Can better sleep lower your risk of Alzheimer’s?

Better sleep supports memory, mood, heart health, and daily function. Scientists are studying whether improving sleep can lower Alzheimer’s risk, but it has not been proven to prevent the disease.

Does treating sleep apnea prevent Alzheimer’s?

Treating sleep apnea can improve breathing, sleep quality, alertness, and cardiovascular health. Studies have not confirmed that treatment prevents Alzheimer’s.

What to remember

Sleeping poorly does not mean that you have or will develop Alzheimer’s disease. What matters more is whether the problem keeps happening, how it affects you during the day, and whether other symptoms are present.

Many sleep problems have causes that can be treated. Finding out what is disturbing your sleep may help you feel and function better now, regardless of its connection to Alzheimer’s.

About the author

Dr. Ruchir P. Patel, MD, FACP, is the Medical Director of the Insomnia and Sleep Institute of Arizona and the founder of Sip2Sleep. He is triple board-certified in sleep medicine, obesity medicine, and internal medicine. Dr. Patel is a multi-year Phoenix Magazine Top Doctor and holds the Inspire Excellence designation.

References

1. Alzheimer’s Association. (2026). 2026 Alzheimer’s disease facts and figures. https://doi.org/10.1002/alz.71345

2. Sabia, S., Fayosse, A., Dumurgier, J., van Hees, V. T., Paquet, C., Sommerlad, A., Kivimäki, M., Dugravot, A., & Singh-Manoux, A. (2021). Association of sleep duration in middle and old age with incidence of dementia. Nature communications, 12(1), 2289. https://doi.org/10.1038/s41467-021-22354-2

3. Tian, Q., Sun, J., Li, X., Liu, J., Zhou, H., Deng, J., & Li, J. (2024). Association between sleep apnoea and risk of cognitive impairment and Alzheimer's disease: a meta-analysis of cohort-based studies. Sleep & breathing = Schlaf & Atmung, 28(2), 585–595. https://doi.org/10.1007/s11325-023-02934-w

4. Yoon, S. S., & Jo, S. A. (2012). Mechanisms of Amyloid-β Peptide Clearance: Potential Therapeutic Targets for Alzheimer's Disease. Biomolecules & therapeutics, 20(3), 245–255. https://doi.org/10.4062/biomolther.2012.20.3.245

5. Chen, C. L., Zhang, M. Y., Wang, Z. L., Deng, J. H., Bao, Y. P., Shi, J., Lu, L., & Shi, L. (2025). Associations among sleep quality, sleep duration, and Alzheimer's disease biomarkers: A systematic review and meta-analysis. Alzheimer's & dementia : the journal of the Alzheimer's Association, 21(3), e70096. https://doi.org/10.1002/alz.70096

6. Shokri-Kojori, E., Wang, G. J., Wiers, C. E., Demiral, S. B., Guo, M., Kim, S. W., Lindgren, E., Ramirez, V., Zehra, A., Freeman, C., Miller, G., Manza, P., Srivastava, T., De Santi, S., Tomasi, D., Benveniste, H., & Volkow, N. D. (2018). β-Amyloid accumulation in the human brain after one night of sleep deprivation. Proceedings of the National Academy of Sciences of the United States of America, 115(17), 4483–4488. https://doi.org/10.1073/pnas.1721694115

7. Cho, G., Mecca, A. P., Buxton, O. M., Liu, X., & Miner, B. (2025). Lower slow wave sleep and rapid eye movement sleep are associated with brain atrophy of Alzheimer's disease-vulnerable regions. Journal of clinical sleep medicine : JCSM : official publication of the American Academy of Sleep Medicine, 21(7), 1165–1173. https://doi.org/10.5664/jcsm.11630

8. Keil, S. A., Jansson, D., Braun, M., & Iliff, J. J. (2025). Glymphatic dysfunction in Alzheimer's disease: A critical appraisal. Science (New York, N.Y.), 389(6756), eadv8269. https://doi.org/10.1126/science.adv8269

9. Musiek ES, et al. Circadian rest-activity pattern changes in aging and preclinical Alzheimer disease. JAMA Neurology. 2018 Jan 29. doi:10.1001/jamaneurol.2017.4719.