Churchill also took a 2 hour nap daily. The man would change into his damn pajamas to do it. Night time sleep is not total sleep. Let's stop glorifying folks who supposedly need so little sleep...they may be getting it other ways.
21 people is a very small sample size. This is a celebrity fluff article. It's hard to do larger psychological studies on successful people because successful people have very low participation in psychological surveys.
Please don't take away any conclusions from such a small sample size.
