Ever wondered how some people are able to function optimally on just a few hours' sleep, while others still find themselves feeling a lot less than ideal after a solid eight hour shift? Those lucky people who thrive on limited but more efficient sleep ('short sleepers') could be benefiting from a gene mutation that allows them to live healthily on only four hours' sleep a night. Professor Ying-Hui Fu is a UC San Francisco professor of neurology and a pioneer in the study of sleep and genetics. She joins the show to discuss the science behind sleep and why it is so important for all of us.