What damage does it cause us to ignore our body clock?
13 May 2014 Last updated at 09:26 BST
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.