A long night’s sleep can be refreshing – but it could also be an early warning sign of Alzheimer’s, scientists have said.
New research suggests that people who regularly get in more than nine hours in bed may be showing early symptoms of the disease.
A US study found participants who consistently slept over nine hours were twice as likely to develop Alzheimer’s or other forms of dementia over the next 10 years as those sleeping less.
Researchers believe that it is a side-effect of changes in the brain caused by dementing illnesses.
Study leader Dr Matthew Pase, from Boston University Medical Center, hopes that the findings could help identify dementia sufferers earlier and help ensure they get appropriate treatment.
Self-reported sleep duration may be a useful clinical tool to help predict persons at risk of progressing to clinical dementia within 10 years.
Persons reporting long sleep time may warrant assessment and monitoring for problems with thinking and memory.
The US study, which followed 2,400 patients which an average age of 72 over ten years, also suggested that having a poor education could also increase the risk of dementia.
Those who had failed to complete a high school degree and also slept for over nine hours a night saw their risk increase six fold.
Dr Rosa Sancho, from Alzheimer’s Research UK, said: “While unusual sleep patterns are common for people with dementia, this study adds to existing research suggesting that changes in sleep could be apparent long before symptoms like memory loss start to show.”
Dementia sufferers are thought to suffer poorer sleep quality, which could explain why they need more rest, she added.
“Understanding more about how sleep is affected by dementia could one day help doctors to identify those who are at risk of developing the condition.”