Adults perform best on seven to eight hours of sleep a night. Period. No more, no less.
That’s one of several findings from what is billed as the world’s largest sleep study with more than 40,000 participants from around the world. Results from the study, launched in June 2017 by neuroscientists from the University of Western Ontario’s Brain and Mind Institute in London, Ontario, were published online Sept. 13 in the journal Sleep.
The online study involved an in-depth questionnaire and a series of cognitive performance activities, according to an Oct. 9 news release on Eureka Alert.
“We really wanted to capture the sleeping habits of people around the entire globe,” said Adrian Owen, a researcher in cognitive neuroscience and imaging. “Obviously, there have been many smaller sleep studies of people in laboratories, but we wanted to find out what sleep is like in the real world. People who logged in gave us a lot of information about themselves. We had a fairly extensive questionnaire and they told us things like which medications they were on, how old they were, where they were in the world and what kind of education they’d received because these are all factors that might have contributed to some of the results.”
At least half of the participants reported averaging less than 6.3 hours of sleep a night. Those who slept four hours or less performed cognitive tests as if they were nine years older than their actual age.
Researchers also found that the amount of sleep for participants to be at their cognitive best is the same for everyone — seven to eight hours. Age was not a factor.
“We also found that people who slept more than that amount were equally impaired as those who slept too little,” said Conor Wild, the study’s lead author.