Whether you prefer burning the midnight oil or going to bed early so you can get up at the break of dawn depends on your genes , according to experts. I jump out of bed each morning, eager to start an active day. But I can hear my neighbour's        alarm clock ringing non-stop every morning and I doubt he gets to work on time. A lot of noise comes from his flat in the evening. He's happy to stay up watching TV till after midnight, while I go to bed early and try to sleep. Well, it might not be his fault after all. I'm called 'a lark  ' and my neighbour 'an owl  '. We all have inside 'clocks' in the brain to control all kinds of bodily functions and it is reset every day by light. These inside clocks run to a different schedule in 'larks' and 'owls'. If you have a fast clock, you like to do things early, and if you have a slow clock, you like to do things late. Because we live in a 24/7 world, scientists believe it's important to understand a person's 'chronotype' - the time of the day when they function the best. It could help us lead a healthier life. A US professor has studied sleeping patterns and thinks work times should be changed and made more individual to fit in with our chronotypes. And he has advice for those who can't choose their working hours: "If that's not possible, we should be more careful about light exposure", says the professor. "You should try to go to work not in a covered vehicle but on a bike. The minute the sun sets we should use things that have no blue light, like computer screens and other electronic devices." Things with blue light are not recommended after sunset because blue light   _  .
will make you nervous may cause sleep problems will reduce your work effect may make you sleepy