Sleeping too much or too little in midlife can impact one's memory later in life, a new study suggests. In addition, those whose sleep patterns have changed over time may also experience memory troubles.
The study, led by Brigham and Women's Hospital, involved more than 15,000 women, 70 and older. All were health professionals free of stroke and depression at the initial cognitive assessment.
Those who slept five hours or less, or nine hours or more a day, either in midlife or later in life, suffered more memory problems -- equivalent to nearly two additional years of age -- than those who slept a regular seven hours a day. At the same time, those participants whose sleep amounts changed by more than two hours a night also experienced a poorer memory when compared with women whose sleep duration hadn't changed.
"Given the importance of preserving memory into later life, it is critical to identify modifiable factors, such as sleeping habits, that may help achieve this goal," said lead researcher Elizabeth Devore in a released statement. "Our findings suggest that getting an 'average' amount of sleep, seven hours per day, may help maintain memory in later life and that clinical interventions based on sleep therapy should be examined for the prevention of cognitive impairment.
"These findings add to our knowledge about how sleep impacts memory," Devore added. "More research is needed to confirm these findings and explore possible mechanisms underlying these associations."
The study was published this week in the Journal of the American Geriatrics Society.
This isn't the only study that indicates a link between sleep and memory. Earlier this year, researchers found that rats' memory of a particular odor was strengthened when they were exposed to that odor during slow-wave sleep, compared with when they were exposed to the odor while awake.
Still another study found that chronic sleep disturbances may speed up the onset of dementias and Alzheimer's disease in older adults. Chronic sleep disturbances can be caused by factors like insomnia, overnight work shifts, and other health conditions.
How much sleep do you get a night? Let us know in comments.