Having trouble sleeping might do more than leave you tired the next day—it could also speed up brain aging.
A new study published in Neurology suggests that chronic insomnia may increase the risk of memory loss, cognitive decline, and brain changes seen in conditions like dementia.
Researchers found that people with long-term insomnia were about 40% more likely to develop mild cognitive impairment or dementia compared to those without insomnia.
This effect was roughly equal to adding three and a half extra years to a person’s brain age.
While the study does not prove that insomnia directly causes brain aging, it does show a strong link between sleep problems and long-term brain health.
“Insomnia doesn’t just affect how you feel the next day—it may also impact your brain health over time,” said lead author Dr. Diego 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.”
The study followed 2,750 older adults, with an average age of 70, who were cognitively healthy at the start. Sixteen percent had chronic insomnia, defined as difficulty sleeping at least three nights per week for three months or more.
Over about 5.6 years, participants completed yearly tests of memory and thinking skills, and some underwent brain scans to check for amyloid plaques—proteins linked to Alzheimer’s disease—and white matter hyperintensities, which signal damage from small blood vessel disease.
During the study, 14% of those with chronic insomnia developed mild cognitive impairment or dementia, compared with 10% of participants without insomnia. Even after adjusting for other risk factors such as age, high blood pressure, sleep apnea, and the use of sleep medications, insomnia remained strongly associated with faster cognitive decline.
The study also looked at sleep changes in the short term. People who reported getting less sleep than usual in the two weeks before testing tended to score lower on memory and thinking tasks, as if they were four years older. They also had more amyloid plaques and more white matter damage in their brain scans. Interestingly, participants who reported sleeping more than usual in the same period had fewer white matter changes.
Certain groups appeared to be at greater risk. People carrying the APOE ε4 gene, which raises the risk of Alzheimer’s disease, showed sharper declines when they also had insomnia.
The researchers emphasized that treating insomnia could be important not only for improving sleep quality but also for protecting the brain. “Our results add to growing evidence that sleep isn’t just about rest—it’s also about brain resilience,” Carvalho said.
The study does have limitations, including the fact that insomnia diagnoses came from medical records, which may miss undiagnosed or less severe cases. Still, the findings add to a growing body of research highlighting sleep as a vital factor for long-term brain health.
Source: KSR.
