Do you toss and turn night after night? While some of us can’t help it, insomnia can wear away at you and your brain’s health.

A new study suggests chronic insomnia — characterized as trouble sleeping for three days a week for three or more months — increases the risk of mild cognitive impairment or dementia.

Researchers followed nearly 3,000 people around 70 years of age over the course of five years. The study showed that after accounting for age, blood pressure, sleep apnea diagnoses and sleep medications, those with insomnia were 40% more likely to develop cognitive issues. They also performed worse on tests measuring a variety of thinking skills.

Notably, those participants’ cognitive function was also comparable to “acting” four years older.

The study suggests that insomnia itself could be a direct contributor to accelerated brain aging because of how it impacts small vessels supplying blood to the brain and amyloid plaques, or the proteins associated with Alzheimer’s disease. Those carrying a gene linked to a higher risk of developing Alzheimer’s demonstrated even sharper declines in memory and thinking skills.

Researchers say treating chronic sleep issues could be a way to preserve brain function and delay the onset of dementia. The study also emphasizes that sleep isn’t just about getting rest, but also about maintaining brain resilience.

So the next time you’re tempted to shrug off a few sleepless nights, think again. You might feel like you can bounce back enough to get through the day, but your brain could be paying the price.

Prioritizing good sleep now could help protect your memory for years to come.