Poor sleep may accelerate brain ageing, according to a study of 27,500 middle-aged Britons. Swedish researchers found that the gap between brain age and chronological age widened by about six months for every one-point decrease in sleep score.
The findings could partly explain why poor sleep has been linked to a higher risk of cognitive decline and dementia. Participants’ sleep quality was scored based on five factors including whether they were a morning or evening person and sleep duration. Insomnia, snoring and daytime sleepiness were also assessed.
They were then divided into three groups — healthy, intermediate and poor sleep.
Their biological brain age was then estimated by using artificial intelligence to analyse MRI scans.
Study leader Abigail Dove, a researcher in the Karolinska Institutet’s Department of Neurobiology, Care Sciences and Society, said: “People with poor sleep had brains that appeared on average one year older than their actual age.
“Our findings provide evidence that poor sleep may contribute to accelerated brain ageing and point to inflammation as one of the underlying mechanisms.”
Researchers also examined levels of low-grade inflammation in the body. Inflammation appeared to explain just over 10% of the link between poor sleep and older brain age.
Other possible explanations included negative effects of poor sleep on the brain’s waste clearance system, and the impact of poor sleep on heart and circulatory health, the experts said.
Ms Dove added: “Since sleep is modifiable, it may be possible to prevent accelerated brain ageing and perhaps even cognitive decline through healthier sleep.”
The findings were published in the journal eBioMedicine.