Are you a lark or an owl? Are you at your best early in the morning or late at night? Whatever the answer, scientists believe they may now know why some of us are early risers while others prefer to burn the midnight oil.
The answer appears to lie in our genes.
Researchers at the University of Surrey say they have found a link between people's preference for mornings or evenings and a gene called Period 3.
This gene is one of those involved in regulating the body's internal clock. It comes in two forms - a shorter and longer one.
I'm a night owl that longs to be a lark.
I've got a very demanding job that needs me to be very alert but yet I can't sleep before 12.30am.
My husband is a lark - so he's awake whilst I'm sleeping and I'm awake whilst he's in bed!
I've tried for years to change - went to bed early, stayed up all night so I'll go to bed early next night, set alarms even on weekends etc etc
Realised that 'snooze' is my enemy and not my friend but I still can't change - has anyone else had this problem?