Genetics I guess. Sleep is overrated.
But the modern studies also show that the old recommondations of 8 hrs sleep were bullshit. 5 hours of good quality sleep per day should be enough to get all the repair work done in the body.
um...yeeeeahhh...im gonna have to...sort of...disagree, with you on that one

i literally need minimum 9-10 hours of sleep to feel 100%. if i get only say, 6 hours then have to force myself up in the morning, i feel like crap throughout the day. maybe its just me...im a light sleeper
one thing ive noticed is that everyone is different as to the Quality of sleep they get; some people sleep like rocks the instant they hit the pillow until they wake up in the morning. no interruptions, no tossing and turning, just pure deep sleep. maybe these people only 'need' 4-5 hours, cause their sleep is pure unstopped quality, whereas those like me lay down, spin for 1-2 hours, sleep 2 hours, get up to piss, spin another hour, get to sleep again, wake up and spin for another hour, etc...over a period of 10 hours only about 5 is actual quality sleep.