Long nights of tossing and turning may be doing more than just leaving people tired the next morning. A new study published on Sept. 10 in Neurology suggests that chronic insomnia could increase the risk of memory problems and even accelerate cognitive decline in older adults.

The research, led by Dr. Diego Z. Carvalho from the Mayo Clinic in Rochester, Minnesota, followed more than 2,800 cognitively healthy older adults over a median period of 5.6 years. Participants underwent annual memory and thinking tests, along with brain scans to measure amyloid deposits — a hallmark of Alzheimer’s disease — and white matter changes linked to brain aging.

The findings were striking. People with chronic insomnia showed faster declines in global cognitive function compared to those without sleep issues. On average, insomnia was linked to a 40 percent higher risk of developing cognitive impairment. Brain scans also revealed that poor sleep was associated with higher levels of amyloid buildup and more white matter hyperintensities, both of which are considered early warning signs of dementia.

“Insomnia doesn’t just affect how you feel the next day — it may also impact your brain health over time,” Dr. Carvalho said in a statement. “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.”

Interestingly, the study found that while insomnia was tied to worse baseline brain health, it did not appear to accelerate the accumulation of amyloid plaques or white matter changes over time. Instead, researchers suggest insomnia may be a marker of existing brain vulnerability rather than a direct driver of these changes.

The findings add to growing evidence that sleep quality plays a crucial role in healthy aging. With dementia rates on the rise worldwide, experts say addressing sleep issues early could become an important part of brain health strategies.

Several of the study’s authors disclosed connections with the biopharmaceutical industry, though the research itself was peer-reviewed and independently published.