Older people who get less deep sleep have higher levels of the brain protein tau, a sign of cognitive decline and Alzheimer’s disease, according to a study.
Slow-wave sleep is the deep sleep people need to consolidate memories and wake up feeling refreshed, said researchers at the Washington University School of Medicine.
The findings, published in the journal Science Translational Medicine , suggest that poor-quality sleep in later life could be a red flag for deteriorating brain health.
“What’s interesting is that we saw this inverse relationship between decreased slow-wave sleep and more tau protein in people who were either cognitively normal or very mildly impaired, meaning that reduced slow-wave activity may be a marker for the transition between normal and impaired,” said Brendan Lucey, an assistant professor at the Washington University.
“Measuring how people sleep may be a non-invasive way to screen for Alzheimer’s disease before or just as people begin to develop problems with memory and thinking,” Mr. Lucey said.
They monitored the participants’ sleep at home over the course of a normal week.