Night owls - is it an unhealthy definition?

Night owls. We all know what they are. Duh. But the night owls that I'm referring to are not those birds who are nocturnal and have big eyes and who sometimes scare the shit out of you when you see one.. No. I'm talking about those people who can't go to sleep early. They are awake so late that you can say they go to sleep when the cock begins to crow.  There are people like that. I'm one of them. It's so hard to hit the haystack early. Or sometimes you don't feel like going to bed. During exams and tests 'Night owls' are up late studying while those 'early birds' prefer to make an early headstart at dawn..which I cannot possibly bring myself to do. Basically, whatever is convenient for us will work for us. But sleeping late does have an impact on your body...so I'm told. Which I'm sure is true. You start to get headaches, start falling asleep in the classroom,  your eyes look like shit.. And you eventually fall sick. My consulting doctor actually told me to get more sleep. More sleep! Oh I love to sleep!  But the world is changing rapidly, people don't get enough sleep. Sometimes 5-6 hours are not enough. We should be getting more. Well, getting more sleep is both a situation which is in our hands and which is not. I think we night owls should get more sleep if we want to stay healthy. Never compromise on sleep. Indeed not.