Restless nights may do more than make you tired, new research shows they could also speed up brain aging.
A study of more than 27,000 middle-aged and older UK adults found that poor sleep habits were linked to brains that appeared older than their actual age. Those with the worst sleep showed brains about a year older on average, while people with moderately poor sleep had brains roughly seven months older.
Published in eBioMedicine, the research used advanced imaging and machine learning to calculate “brain age” from over 1,000 features. A higher brain age than real age is considered an early sign of declining brain health. “Having an older brain age is an early indicator of a departure from optimal brain health,” the researchers wrote.
To measure sleep health, scientists used five factors: going to bed early, sleeping 7–8 hours, avoiding insomnia, not snoring, and not feeling overly sleepy during the day. Only 41% of participants had four or five of these traits. More than half scored in the middle, and 3% had poor sleep with one or none. Each one-point drop in the sleep score translated to the brain appearing about six months older. Being a night owl, sleeping too much or too little, and snoring showed the strongest links.
Men were more affected than women. Among men, each drop in sleep score corresponded to brains about 2.5 months older, while the link in women was weaker and not statistically significant. Genetic risk for Alzheimer’s did not change the results.
The study also tied poor sleep to inflammation, which explained about 10% of the link to older brain age. Since participants were healthy and free of dementia, the findings suggest that poor sleep may drive brain aging rather than just result from it.
Researchers emphasize that nearly 60% of people had less-than-ideal sleep, highlighting sleep health, along with exercise, diet, and mental activity, as a potentially modifiable factor that could help protect long-term brain function.