If you sleep six hours a night for twelve days, Adusumilli says—and that’s about how much many Americans sleep all year round—your cognitive and physical performance becomes virtually indistinguishable from that of someone who has been awake for twenty-four hours straight. (The same effect is produced by six days of four-hour nights.) And the performance of someone who has been awake for twenty-four hours straight is similar to that of someone with a blood alcohol level of 0.1 per cent. In other words, “normal” amounts of sleep deprivation have us acting like we’re drunk. (Charles Czeisler recalls presenting these facts to a Times journalist; when the journalist handed in the story, the editor said it couldn’t possibly be true. Most people in the newsroom were sleep-deprived, and they still managed to produce the Times every day. Surely an intoxicated newsroom would be incapable of such a feat.)In my whole life, I've almost never used an alarm clock to wake up in the morning unless I had a plane to catch. It's one reason I don't like traveling.
That explains it
From a three-part New Yorker article about sleep disorders:
By Texan99 on Saturday, July 11, 2015