Does science support seven to nine hours of sleep a night?


Neuroscientists from Western University’s Brain and Mind Institute launched the world’s largest sleep study in June of 2017.  More than 40,000 participants from around the world took part in the online study.  The initial results of the study were released in 2018.

The study consisted of an in-depth questionnaire and a series of cognitive performance activities to gage the relationship between sleep and cognitive performance.

Initial results included:

  • Seven to eight hours of sleep was optimal for brain performance
  • Too little and too much sleep equally impaired brain performance
  • Approximately half of all participants reported sleeping less than 6.3 hours per night
  • Reasoning and verbal abilities were two abilities most strongly impacted by lack of sleep
  • Short-term memory performance was relatively unaffected
  • Participants who slept four hours or less had cognitive performance equivalent to a nine year old
  • There was some evidence that even a single night of seven to eight hours of sleep can have a positive impact on the following day’s cognitive performance

The following website was used in answering the question;