A new study reports that when it comes to sleep, it's actually possible to get too much of a good thing.
According to UPI, research shows getting too much or too little sleep may increase the risk for cognitive decline, or dementia, in older adults.
Chinese researchers analyzed the sleep habits of more than 20,000 English and Chinese adults age 48 to 75.
They found that people who slept for fewer than four hours or more than 10 hours per day showed evidence of declines in cognitive function.
The cognitive declines included difficulties in memory and language comprehension.
Also, people who slept less than four or more than ten hours a day declined cognitively more quickly than those who slept seven to nine hours per day.
It's usually believed that sleep deprivation might lead to cognitive decline, but it's unclear why too much sleep might be bad for cognitive health. Dr. Yue Leng, Study Commentary Author Professor of Psychiatry, University of California-San Francisco.