Previous studies have shown that too little sleep can interfere with daily functioning. Over time, it can even harm cognitive development. Yet researchers from the Brigham and Women’s Hospital (BWH) believe that too much sleep can also affect memory, particularly in women.
“Sleep Duration In Midlife and Later Life In Relation to Cognition: The Nurses’ Health Study,” said lead study author Elizabeth Devore, ScD, instructor in medicine in the Channing Division of Network Medicine, via Science Blog.
For the study, researchers found that women who slept five or fewer hours, or nine or more hours per day in midlife or later in life, typically had worse memory than those who typically slept an average of seven hours a day.
Findings also showed that women whose sleep duration changed by more than two hours per day over time had worse memory than those that remained constant.
“Women who reported longer and shorter sleep durations, so the extremes on both ends in mid-life and later life, had lower cognitive function levels in later life than the women who slept sort of what we consider an average amount of sleep, which is about seven hours per night,” said lead researcher Elizabeth Devore, ScD, instructor in medicine in the Channing Division of Network Medicine at BWH, via CBS Local. “It’s a good suggestion that sleep really is important in later life cognition.”