WAKING up feeling knackered could be an early sign of dementia, experts have warned.
They found getting a bad night’s kip is a red flag sign for Alzheimer’s disease.
Tests showed people who don’t fall into a deep enough sleep – where you wake up feeling refreshed – have higher levels of a toxic protein in the brain.
It means using fitness trackers to monitor sleep could one day help doctors diagnose the disease years before the tell-tale memory loss sets in.
Dr Brendan Lucey, of Washington University in St Louis, said: “Measuring how people sleep may be a noninvasive way to screen for Alzheimer’s disease before or just as people begin to develop problems with memory and thinking.”
There are around 850,000 Brits living with dementia – and that number is set to rise to over one million by 2025.
The brain changes that result in Alzheimer’s start slowly and silently.
Up to 2o years before the tell-tale signs of memory loss and confusion are obvious, toxic proteins begin to collect forming plaques in the brain.
Tangles of these proteins begin to appear and key parts of the brain begin to waste away.
It is only at this point that people begin to show the unmistakable signs of brain decline.
Scientists across the world are working to try and find a way of tracking Alzheimer’s before these brain changes happen – to catch the disease in its earliest stages.
And Dr Lucey’s team believe sleep might be a first step.
They studied 119 people aged 60 or older – most (80 per cent) were cognitively normal – so didn’t have dementia. The remaining 20 per cent were “mildly impaired”, researchers noted.
The team tracked the volunteers’ sleep at home over the course of a week – taking brain wave readings, as well as body movements.
All those taking part kept sleep logs, recording their night-time sleeping and day-time naps.
Measuring how people sleep may be a noninvasive way to screen for Alzheimer’s disease before or just as people begin to develop problems with memory and thinking
Dr Brendan Lucey, of Washington University in St Louis
And the scientists then measured levels of amyloid beta and tau proteins in the brain – from samples of fluid from the spinal cord.
Dr Lucey said: “The key is that it wasn’t the total amount of sleep that was linked to tau, it was the slow-wave sleep, which reflects quality of sleep.
“The people with increased tau pathology were actually sleeping more at night and napping more in the day, but they weren’t getting as good quality sleep.”
The findings, published in Science Translational Medicine, also found daytime napping was linked to higher levels of tau proteins – suggesting the more a person naps the more likely they are to develop dementia.
Dr Lucey said if future studies show similar results, sleep monitoring could be a cheap and easy way to screen for Alzheimer’s early on.
He added: “I don’t expect sleep monitoring to replace brain scans or cerebrospinal fluid analysis for identifying early signs of Alzheimer’s disease, but it could supplement them.
“It’s something that could be easily followed over time, and if someone’s sleep habits start changing, that could be a sign for doctors to take a closer look at what might be going on in their brains.”
But experts in the UK urged caution – pointing out more research is needed.
Dr Laura Phipps of Alzheimer’s Research UK said the findings don’t tell us if poor sleep is the cause of the changes seen in the brains of adults with dementia.
She said: “It doesn’t tell us whether these brain changes are caused by the sleep problems or vice versa.”
Dr James Pickett, head of research at Alzheimer’s Society agreed.
“It’s too soon to say if trying to change our sleep habits might affect our changes of developing dementia,” he said.
“But there’s good evidence that being physically active and eating healthily can reduce the risk.
“So try to choose an apple over the packet of crisps, and get out as much as possible.”