The study isn’t the first time the idea of eight hours sleep has been brought into question. According to sleep scientist Daniel Gartenberg in an interview with Quartz, even if you’re in bed for eight hours, you’re probably only asleep for just over seven.

“In order to get a healthy eight hours of sleep, which is the amount that many people need, you need to be in bed for 8.5 hours,” said Gartenberg. “The standard in the literature is that healthy sleepers spend more than 90% of the time in bed asleep, so if you’re in bed for eight hours, a healthy sleeper might actually sleep for only about 7.2 hours.”

It seems we really should be focusing on quality and depth over quantity, after all.

Why 7 hours of sleep is what we should be aiming for, according to new Cambridge University research