Why sleeping at night 8 hours is better for health than morning?

Well in our bodies there is what is called a biological clock.You must have heard about "jet lag"when i go to usa i am going nine hrs behind and even though it might be night and time for sleep my body is not tuned and no matter how tired i am i will not be able to sleep There is something called the CIRCADIAN RHYTM.The body releases some enzymes,harmones at a particular time So if you get a sleep of 8 hours or so at night it is better then ten hours during the day.This is because a pineal gland which is concerned with sleep cycle works best at night i can go on but i do not want to confuse you guys draamir mirza