The time you wake up one day, to the time you wake up the next, averaged out over a long period of time. For most people it's right around 24 hours, as it shou

The time you wake up one day, to the time you wake up the next, averaged out over a long period of time. For most people it's right around 24 hours, as it should be. Circadian technically means every 24 hours, so a better word may have been just "body clock": http://en.wikipedia.org/wiki/Circadian_rhythm#Criteria http://en.wikipedia.org/wiki/Circadian_rhythm#Criteria