Just one bad night's sleep 'raises levels of an Alzheimer's biomarker by 17%'

Scientists deprived a group of healthy, young men of a decent night's kip. [Photo: Getty]
Scientists deprived a group of healthy, young men of a decent night's kip. [Photo: Getty]

Just one bad night’s sleep can raise levels of an Alzheimer’s biomarker in the blood, research suggests.

Scientists from Uppsala University in Sweden deprived 15 healthy men of a decent night’s kip.

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The next day, levels of the protein tau had risen by 17% in the men’s blood.

Tau is known to cause tangles in the areas of the brain related to memory. It then moves through the vital organ as symptoms progress.

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“Many of us experience sleep deprivation at some point in our lives due to jet lag, pulling an all-nighter to complete a project, or even doing shift work, working overnights or inconsistent hours,” study author Dr Jonathan Cedernaes said.

“Our exploratory study shows even in young, healthy individuals, missing one night of sleep increases the level of tau in blood, suggesting that over time, such sleep deprivation could possibly have detrimental effects.”

In the UK, 850,000 people live with dementia, with Alzheimer’s being the most common form of the disease, Alzheimer’s Research UK statistics show.

Around 5.8m live with Alzheimer’s in the US, according to the Alzheimer’s Association.

READ MORE: Alzheimer's drug could reduce cognitive decline by up to 40%

Past studies suggest sleep deprivation can cause tau to accumulate in the spinal fluid of older adults.

Head trauma has also been linked to elevated levels in the blood.

To learn more, the scientists looked at men - with an average age of 22 - who tended to get seven-to-nine hours shut eye a night.

The men were first allowed to sleep as normal for a few nights.

They then stayed up with the lights on, playing games, watching TV or talking.

Results, published in the journal Neurology, show their tau levels rose by 17%, compared to 2% after a good night’s rest.

Other Alzheimer’s biomarkers remained unchanged.

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“It's important to note while higher levels of tau in the brain are not good, in the context of sleep loss we do not know what higher levels of tau in blood represent”, Dr Cedernaes said.

“When neurones are active, production of tau in the brain is increased.

“Higher levels in the blood may reflect these tau proteins are being cleared from the brain or they may reflect elevated tau levels in the brain.”

He adds further studies need to investigate how long tau remains in the blood and whether it is later linked to dementia.

“Such studies could provide key insight into whether interventions targeting sleep should begin at an early age to reduce a person's risk of developing dementia or Alzheimer's disease,” Dr Cedernaes said.

The scientists note they only looked at young men, with results potentially being different in women or older people.

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