Deep sleep protects against Alzheimer's, study suggests

Portrait of young woman with sleep mask in bed
Research is increasingly linking a lack of sleep to dementia, of which Alzheimer's is the most common form. (Posed by a model, Getty Images)

Deep sleep could help ward off Alzheimer’s, research suggests.

The memory-robbing disease is thought to come about when abnormal clusters of the protein amyloid-beta forms plaques between nerve cells in the brain, causing tissue to die and the vital organ to shrink.

Research is increasingly linking insomnia to dementia, the umbrella term for a range of conditions that cause a decline in brain function, of which Alzheimer’s is the most common.

To learn more, scientists from the University of California in Berkeley analysed the deep sleep patterns of 32 healthy people in their seventies.

Deep sleep occurs when body temperature drops and the brain begins to produce slow, rhythmic electrical waves. This is different from the rapid-eye movement phase of sleep, when dreams generally occur.

Read more: Men in manual labour jobs may face higher risk of dementia

After monitoring the participants for up to six years, brain scans revealed those who got the least deep sleep had higher levels of amyloid beta, according to results published in the journal Cell. It is unclear whether they were diagnosed with Alzheimer’s.

Deep sleep is thought to help wash away excessive amyloid beta. Healthy levels of the protein play a critical role in nerve cell growth and repair.

MRI Brain Scan of head and skull with hand pointing
Alzheimer's is thought to occur when abnormal proteins form plaques and tangles around and within nerve cells, causing tissue to die and the brain to shrink. (Stock, Getty Images)

“There is something about this deep sleep that is helping protect you,” said study author Professor Matthew Walker, according to npr.

The scientists hope an individual’s Alzheimer’s risk could one day be assessed based on their sleep patterns.

Read more: Eating soy may help ward off dementia

“We have a specific sleep signature right now that seems to help us better understand where you may sit on the Alzheimer's risk trajectory in the future,” said Professor Walker.

“Can I look into your future and can I accurately estimate how much beta-amyloid you're going to accumulate over the next two years, the next four years, the next six years, simply on the basis of your sleep tonight?”

Dementia affects around 850,000 people in the UK, of whom between half (50%) and three quarters (75%) have Alzheimer’s. More than 5 million people have Alzheimer’s in the US.

Watch: Actor Millie Bobby Brown reflects on ‘evil’ Alzheimer’s that killed her grandmother

Alzheimer’s is also linked to the abnormal build-up of the protein tau, which forms tangles within nerve cells. A lack of deep sleep has previously been linked to higher levels of tau.

The Berkley scientists are looking at whether deep sleep can be induced to help ward off the memory-robbing disease.

In rodents, stimulating a specific structure in the brain is said to cause the slow electrical waves.

When it comes to people, some research suggests listening to rhythmic sounds has the same effect.

Treating underlying sleep disorders may also be beneficial. Studies have found people with obstructive sleep apnoea, when breathing stops and starts during sleep, are more likely to develop dementia.

Read more: Three lifestyle habits could cut dementia rates in England by 8.5%

When it comes to getting a good night’s shut eye, the NHS recommends getting up and going to bed at the same time every day, even on weekends.

Spending the evening winding down by having a warm bath, listening to relaxing music or doing gentle stretches can also aid sleep.

Writing a to-do list for the next day can help to clear the mind of any distractions and reduce stress.

Avoiding screens an hour before bed can also aid shut eye. The bedroom should be sleep-friendly, with a comfortable mattress and thick curtains to block out any light.

Watch: Dementia patient, 92, plays Beethoven on piano