The connection between Alzheimer’s and sleep 

Research suggests there is a link between Alzheimer’s disease and poor sleep. It’s possible that quality sleep may be important in reducing your risk of Alzheimer’s. Improved nighttime habits can also help people who already have dementia get better rest.  

Sleep and Alzheimer’s disease

One challenge in understanding the link between poor sleep and Alzheimer’s disease is that it is difficult to separate cause and effect. While we know that Alzheimer’s disease can disrupt the sleep cycle, it’s not established whether poor quality sleep contributes to the development of Alzheimer’s.

One thing is clear, though: Symptoms of the disease can make sleeping harder, while sleep disturbances can also make Alzheimer’s symptoms worse. For example, people with Alzheimer’s disease may experience delusions and restlessness and be prone to wandering. Those symptoms can make it hard to sleep. And if poor sleep continues, it can exacerbate the progression of Alzheimer’s disease. 

The importance of deep sleep

When you sleep, you go through four stages:

• Stage 1: This is when you wind down and fall asleep. This is light sleep, and you are still fairly easy to wake.  
• Stage 2: Still in light sleep, your body temperature decreases, your muscles relax, and your breathing and heart rate slow.  
• Stage 3: This is deep, or slow-wave sleep, when you are the most relaxed.  
• Stage 4: This is rapid eye movement (REM) sleep. Your body is at rest, but your brain is at its most active. You have your most vivid dreams, and your heart rate and breathing are increasing.  

During uninterrupted sleep, you go through cycles that include each of these four stages about every 90 to 120 minutes. While all four are important to your health, deep sleep (Stage 3) is often studied in connection with Alzheimer’s disease and other types of dementia.  

Deep sleep is when your body and brain repair damage. It’s also associated with building the immune system, reducing inflammation and regulating blood sugar levels. Deep sleep also helps preserve cognitive function and memory and helps with the ability to learn. Research show that deep sleep may also actually remove waste from the brain.

According to a 2025 study, getting less slow-wave sleep and REM sleep (Stages 3 and 4), makes you more likely to have reduced brain volumes in certain regions. This study adds to research showing that less brain activity during sleep may be linked to brain shrinkage and a higher risk of Alzheimer's disease. 

Can quality sleep prevent Alzheimer’s?

Poor sleep has not been proven to cause Alzheimer’s disease or other forms of dementia. But it may contribute to overall risk, and some research shows it may even be one of the first signs of Alzheimer’s disease — even before cognitive (brain-related) symptoms.  

So, while good sleep habits aren’t guaranteed to prevent Alzheimer’s, they may help reduce risk. High-quality sleep may help reduce your risk of heart disease and diabetes, too.  

Habits that may reduce Alzheimer’s risk

To help improve sleep and get more restorative deep sleep, start with good habits, such as:

• Add movement to your day: Physical activity, including simple walking, during the day can help you sleep better at night.
• Avoid napping, if possible: Naps can interfere with quality nighttime sleep.
• Check your medications: Some Alzheimer’s medications can affect sleep and should be taken earlier in the day. Ask your doctor about when to take your medications.
• Keep a regular sleep schedule: Aim to go to bed and wake up at the same times every day.
• Soak up the sun: Natural light during the day can help your internal clock stay on track. If you live in a naturally dark region, light therapy (using a device to introduce light) may be an option.
• Use the evening to wind down: Avoid overstimulating activities in the evening. As bedtime approaches, listen to music, read or do other quiet tasks that help calm you.

While researchers continue to study the connection between Alzheimer’s disease and sleep, prioritizing healthy sleep habits is a practical step you can take right now.