Why Some People Can Get by on Just 4 Hours of Shut-Eye

Ever wonder why some people seem to be able to get by on a ridiculously small amount of sleep? Well, researchers from the University of California, San Francisco (UCSF) have some insight: It may well have to do with genetics, at least with some people.

UCSF announced this week that, after 10 years of research, scientists had identified a second gene related to this “short sleep” phenomenon, wherein people appear to be completely fine, over the long term, with just four to six hours of sleep per night. (Researchers had already identified one gene previously.)

“Before we identified the first short-sleep gene, people really weren’t thinking about sleep duration in genetic terms,” said Ying-Hui Fu, professor of neurology and a member of the UCSF Weill Institute for Neurosciences, in a statement.

Specifically, this second discovery involves a mutation of the “ADRB1 gene,” according to the study published in the journal Neuron. And while getting by on less sleep may seem enviable (especially for this group of people, who may not suffer the overall detriments associated with fatigue due to insufficient rest), don’t feel too bad—this specific mutation is extremely rare.