Sleeping too much increases the risk of dementia. How long is the best time to sleep a day
On October 9, Miami Miller University in Florida published a study: people who sleep nine hours a night have a significant decline in memory and language skills, which are the early symptoms of dementia such as Alzheimer's disease.
The study investigated the sleep of 5247 Hispanic Americans aged 45 to 75 for seven years.
The results showed that people who slept 9 hours a night had a comprehensive decline in cognitive ability, learning ability, language fluency and memory.