It’s the largest sleep study ever done and confirms what may doctors have said for years – you need 7 to 8 hours of zzz’s.
Neuroscientists from Western University in London asked participants to fill out questionnaires and a series of cognitive performance activities before and after sleeping.
People from 173 different countries were surveyed, the majority coming from the UK, Canada, USA and Portugal.
Over the course of about one year, beginning in June 2017, the study found that people who slept 7 to 8 hours per night performed better cognitively than those who got both more or less sleep.
The study says most people were getting less than the optimal amount, clocking in on average at 6.4 hours per night.