i often read in the magazines about super efficient successful people who are all like

"oh yeah i usually go to bed at one in the morning and then get up at 5 so i can go to the gym and then start work by 7 and then blah blah blah i get loads done as i only get 4 hrs sleep a night..."

i am knackered if i get less than 8 HRS A NIGHT.

how do people's survive on little sleep?