You’re 40% more likely to develop dementia if you have trouble sleeping this many times a week

Don’t sleep on this troubling sign that may increase your risk of dementia.

Age, genetics, high blood pressure, unmanaged Type 2 diabetes, smoking and untreated hearing loss are among the major risk factors for dementia, a progressive condition that affects memory, thinking and the ability to perform daily tasks.

Researchers from the Mayo Clinic wanted to explore how chronic insomnia affects brain aging and dementia risk. Sleep is vital for the brain to perform essential functions like cellular repair, memory processing and the removal of toxins and waste products.

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“Insomnia doesn’t just affect how you feel the next day — it may also impact your brain health over time,” said study author Dr. Diego Z. Carvalho of the Mayo Clinic.

“We saw faster decline in thinking skills and changes in the brain that suggest chronic insomnia could be an early warning sign or even a contributor to future cognitive problems.”

Carvalho’s team tracked 2,750 cognitively healthy older adults with an average age of 70 over five years.

The participants took annual thinking and memory tests and some had brain scans to look for signs of brain damage and Alzheimer’s disease, the most common form of dementia.

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About 16% had chronic insomnia — defined as three or more days a week of sleep troubles for at least three months.

Fourteen percent of this group developed mild cognitive impairment or dementia, compared to 10% of those without insomnia.

The researchers took into account factors like age, high blood pressure, sleep medication use and a sleep apnea diagnosis.

They determined that chronic insomniacs have a 40% higher risk of mild cognitive impairment or dementia, the equivalent of 3.5 additional years of aging.

The researchers also noted that people who reported sleep struggles at the start of the study initially had lower cognitive test scores and more white matter hyperintensities and amyloid plaques, key indicators of preclinical dementia.

Carrying the APOE e4 gene variant — which significantly increases Alzheimer’s risk — meant steeper declines in memory and thinking skills during the study period.

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On the other side, participants who reported getting better sleep than usual were more likely to have fewer white matter hyperintensities.

“This reinforces the importance of treating chronic insomnia — not just to improve sleep quality but potentially to protect brain health as we age,” Carvalho said.

“Our results also add to a growing body of evidence that sleep isn’t just about rest — it’s also about brain resilience.”

The findings were published in Wednesday’s issue of Neurology, the medical journal of the American Academy of Neurology.

One limitation is that the data came from medical records, which do not include undiagnosed insomnia cases or reflect the severity of insomnia.

The American Academy of Sleep Medicine reports that about 12% of Americans have chronic insomnia.

Treatment options include breaking bad habits like alcohol and cognitive behavioral therapy to change the thoughts and behaviors that contribute to insomnia.