A study by researchers at Boston University School of Medicine has found that people who sleep more than nine hours at night have double the risk of developing dementia in 10 years than those who sleep less.
The study, based on data from the Framingham Heart Study, which followed participants for 10 years to see who developed the disease, is published in the February issue of Neurology. In addition to their sleep patterns, researchers also found that those who developed dementia had smaller brain volume.
“Participants without a high school degree who slept for more than nine hours each night had six times the risk of developing dementia in 10 years as compared to participants who slept for less. These results suggest that being highly educated may protect against dementia in the presence of long sleep duration,” says Sudha Seshadri, the study’s co-author and a professor of neurology at the medical school.
While the long sleep doesn’t seem to cause, it can be seen as a symptom due to brain changes that occur with the disease, a university news release notes. A change in sleep duration may be a key in early detection.