New research reveals the amount and quality of sleep you get may actually affect your memory as you get older.

Yo-El Ju, MD, from Washington University School of Medicine and his colleagues tested the sleep patterns of 100 dementia-free people between the ages of 45 and 80, half of whom had a family history of Alzheimer’s disease. A device was used to measure sleep for two weeks, and the participants also kept sleep diaries and filled out questionnaires.

The average time a person spent in bed during the study was about eight hours, but the average sleep time was 6.5 hours due to short periods of wakefulness during the night.

After the study period, researchers learned that 25 percent of the volunteers had evidence of amyloid plaques, a precursor of Alzheimer’s disease. What’s more, people who woke up more than five times per hour were more likely to have amyloid plaque build-up compared to people who didn’t wake up as much.

The study also found those people who slept “less efficiently” were more likely to have the markers of early stage Alzheimer’s disease than those who slept more soundly.

“The association between disrupted sleep and amyloid plaques is intriguing, but the information from this study can’t determine a cause-effect relationship or the direction of this relationship,” Ju said in a press release. “We need longer-term studies, following individuals’ sleep over years, to determine whether disrupted sleep leads to amyloid plaques, or whether brain changes in early Alzheimer’s disease lead to changes in sleep.”

He added, “Our study lays the groundwork for investigating whether manipulating sleep is a possible strategy in the prevention or slowing of Alzheimer disease.”