There's been research on it, although not as much as I wish. I'm one of those people who simply needs more sleep than the average, as does my dad... meanwhile, my mother chugs away just fine on 5 hours or so, and is in better health than either of we men are.

People who accomplish a great deal are often one of these "short sleepers" who can subsist on 5 or even 4 hours of sleep a night; think top-of-their-field salesmen, CEOs, and so on. They simply have more time to get things done, and don't have the problem longer sleepers do that getting 4-5 hours on a regular basis would start to affect their performance in every area of life, not to mention their health.