Why do we inevitability to sleep for 8 hours?

Why can't we just sleep for five or six? Why does it enjoy to be eight?Why do we inevitability to sleep for 8 hours?
The body does all its repairing while we sleep, so we procure nicer skin hair, condition and everything. Statistics show that people who sleep for exactly eight hours live longer than those who sleep for more or smaller number than that
I have no model but if dont get a sleep for six and a partly..My head starts to twinge.
Because 16 hours of work and using your body is enough!
The body and spirit want time to rebuild after the world "beat up on both".
GOD bless us one and all, other.
MBA - Boston Univ.
Not necessary, 5 hr sleep adequate, but need to whip short naps 5 to10 minutes at lowest possible 2 times in the morning time to tranquilize the mind and body..
most aduts need single 6hours of sleep 0-7 need 12-14 hours 8-14 necessitate 8hours 15-18 need 8-10hours 19-28 entail about 8hour and up to 55 6hours is