The fact that people say you should get 8 hours of sleep a night really is an average. My husband for instance continually amazes me be cheerfully hopping out of bed, eating breakfast, dressing in a color coordinated outfit, feeding the cats, brushing his teeth and washing his face plus occasionally showering and shaving before leaving for work. I, on the other hand, with an equal amount of sleep barely manage to assume a mind over mattress vertical orientation after the 3rd snooze button session, eating no breakfast, and wake up at my desk 20 minutes after leaving my pillow wondering who let me out of the house in that outfit and grateful that I at least have something on both my top and bottom and wishing that I kept a hairbrush and toothbrush at work, not to mention makeup and a spare outfit.
There will always be people who can live with 4-8 hours a night and "not only walk the following morning, but also make remarkably informed fashion decisions; and those of us who need "eleven" or more hours of sleep if we even hope to fall successfully onto the wooden floor beside the bed." as Dooce says.