LONDON

People who sleep poorly may have brains that appear nearly a year older than their actual age, according to a new study of more than 27,000 adults age 40 to 70.

The research, published in British medical journal the Lancet, analyzed participants’ sleep habits and brain MRI scans, using artificial intelligence to estimate each person’s “brain age” — a biological measure based on patterns such as tissue loss, cortical thinning, and blood vessel damage.

Researchers found that those with poor sleep profiles had brains that looked significantly older than their chronological age.

Each drop in sleep quality was linked to roughly six months of extra brain aging.

On average, people with poor sleep habits — such as insomnia, snoring, abnormal sleep duration, or a late chronotype — had brains that appeared about one year older than their actual age.

“Having a brain age higher than your actual age can be a signal of departure from healthy ageing,” the researchers said.

Previous studies have shown that an older-appearing brain is linked to faster cognitive decline, dementia risk, and even earlier death.

The team also found that inflammation may partly explain the link.

Poor sleep can raise levels of inflammation in the body, which in turn may harm blood vessels and brain cells. Inflammation accounted for about 10% of the connection between sleep quality and brain aging.

While brain aging cannot be avoided, the researchers said lifestyle choices can help slow it down.

Keeping a regular sleep schedule, limiting caffeine, alcohol, and screen time before bed, and creating a quiet, dark sleep environment may protect long-term brain health.