What damage does it cost to ignore our body clock?

Body clocks rule our lives, determining everything from how we sleep and the way our brain works, to the likelihood of a us ever having a heart attack.

However, leading scientists are warning that as our lives become busier, we are increasingly ignoring it potentially causing serious consequences to our health.

As part of the BBC's Day of the Body Clock, James Gallagher reports on the dangers of not getting enough sleep.

And how about you? Can you answer these questions? Work with a partner if possible:

Do you sometimes have problems getting to sleep? What do you do?
Have you ever overslept and missed something important?
Are you a light sleeper or do you sleep like a log?
Have you ever been jet-lagged? Where were you going? How long did it take you to recover?
Do you take or have you taken sleeping pills?
Have you ever fallen asleep at an embarrasing moment, for example during a class?
Do you snore? have you ever shared a room with someone who snores? Was this a problem?