Not everyone needs 8 hours of sleep to function properly. Some people can feel well-rested and show no negative effects of sleep deprivation, even after just 4 hours of sleep, which is likely the result of a genetic mutation.

A recent study has reported that a mutation in salt-induced kinase 3 (hSIK3-N783Y)—a gene critical for regulating sleep duration and depth—may be the reason why some people are natural short sleepers (NSS).

The findings of this study are published in Proceedings of the National Academy of Sciences.