Demential danger increases 40% when sleeping more than 8 hours a day

Demential danger increases 40% when sleeping more than 8 hours a day. January. 05, 2017 07:13. by Youn-Jong Kim zozo@donga.com.

Research shows more sleep leads to increased danger of dementia. A team led by Professor Myung Seung-kwon of National Cancer Center International Caner Graduate School and another team led by Professor Kim Hong-bae of Myongji Hospital family medicine department announced the results of their research on 10 sleep and cognitive functions related research released on international academic journals in 2009-2016.

According to the findings, people who sleep eight to nine hours a day has 38 percent higher danger of cognitive disorder than those with seven to eight hours of sleep. The danger of getting dementia surges by 42 percent.

When sleep hours topped eight hours, the dementia danger was around 40 percent even if people sleep 10 hours or 15 hours. Analysis by gender, age and region also showed that long sleep hours increased the danger of cognitive function decline by 40 percent.

"The correlation between long sleep hours and cognitive disorder has yet to be identified," Professor Myung said. "Based on biological mechanism, however, longer sleep hours increases infection biomarker." This means increasing sleep hours facilitates infection response in the brain. In fact, Alzheimer's, which accounts for 50 percent of dementia, is a disease in which infection is occurred, leading to the shrinking of brain.

According to the research teams, there are foreign findings that for every one hour increase in sleep hours, the infection related figure in the body increased by seven to eight percent. By contrast, people suffering from initial dementia tend to sleep long, and that is why such results were possible, Myung said.

All said, maintaining optimal sleep hours is desirable. U.S.-based National Sleep Foundation in February last year changed optimal sleep hours for children from 10 to 11 hours to nine to 11 hours. It recommended people aged 26-64 to sleep an optimal seven to nine hours and seven to eight hours for those aged 65 and older. "In order to prevent dementia, we should consider lowering the ceiling of optimal sleep hours by around an hour," Professor Myung said. The latest findings were published on an online edition of international academic journal New Management at the SCI level.