I find it hard to sleep more than 7 hours a night but as I'm tired all of the time I'm sure that's not enough and this research doesn't apply to me; but apparently some people have DNA that allows them to get away
What would you do if you had 60 days of extra free time a year? Ask Abby Ross, a retired psychologist from Miami, Florida, a “short-sleeper”. She needs only four hours sleep a night, so has a lot of spare time to fill while the rest of the world is in the land of nod.
“It’s wonderful to have so many hours in my day – I feel like I can live two lives,” she says.
Short-sleepers like Ross never feel lethargic, nor do they ever sleep in. They wake early – normally around four or five o’clock – raring to get on with their day. Margaret Thatcher may have been one – she famously said she needed just four hours a night, whereas Mariah Carey claims she needs 15.
http://www.bbc.com/future/story/20150706-t...o-barely-sleeps