I usually sleep after 12 am. Since I was in high school, I had trained myself that way and till now, its become a trend. I read some article somewhere, that when you sleep late you tend to wake up earlier as well and have confirmed this to be true. Am that kind of a person who will go upto late night to finish a certain task but I cannot wake up in the morning to do the task. I also read an article somewhere that those kind of people who read upto late night are always bright unlike those who wake up in the morning. I don't know how IQ is related to sleeping and waking up. What I know that matters is the quality of sleep you get and the duration. What matters is the duration you sleep. Six to eight hours in a day is a highly recommended time no matter what time you go to bed.