Before you hit that snooze button, consider this: oversleeping may be responsible for accelerating dementia, new research suggests, as people who sleep for 9 or more hours daily have more rapid cognitive decline than those who sleep six to eight hours a night, according to medwireNews.
"Since sleep duration is potentially modifiable, the relation between sleep duration and cognitive decline might well have practical implications for the primary prevention of [dementia and cognitive] disorders," wrote the Spanish research team, led by Julián Benito-León (University Hospital "12 de Octubre," Madrid, Spain).
The latest study took place over a period of three years involving 2,700 participants in their sixties and seventies. Each participant was assessed using the mini-mental state examination (MMSE) before the study took place, the test designed to analyze the changes in brain function. Over the course of three years, individuals kept detailed records of their sleeping patterns, including the amount of hours they spent in bed.
Forty-nine percent were "normal" sleepers who got an average of six to eight hours a night, and 40 percent were "long" sleepers who slept for nine or more hours a night. The remaining participants slept five hours or less every day.
After the experiment was over, participants again took the MMSE, and though all groups of sleepers scored lower than they had initially, brain function decline was the greatest for "longer" sleepers. Researchers accounted for confounding variables such as age.
"This research suggests that the length of time you sleep and cognitive health might be linked," said Doug Brown of the Alzheimer's Society. "But further studies are needed to understand whether sleep duration is a cause or effect of cognitive decline."
The researchers noted in the Journal of Psychiatric Research that although longer sleeps showed a significantly greater MMSE reduction, "in absolute terms, it was a modest change," according to medwireNews.
