What is it like to feel rested after sleeping just four hours a night? "Daylight saving time begins Sunday at 2 a.m. in most of the U.S.—except for Hawaii and Arizona. But for some genetically blessed people, a loss of one hour of sleep is not a problem. In fact, sleeping fewer than the recommended seven or eight hours is the norm. They naturally feel refreshed and ready to go—at 4 a.m. These 'short sleepers' have a mutation on a gene known as hDEC2, that regulates their sleep-wake cycle. This mutation allows them to function on less sleep, researchers say."