The circadian rhythm is the cycle that dictates what your body does when: secretions, sleep, awake, temperature fluctuations, etc; but most importantly, when it does those things.
A circadian backflip is something
shift workers and people stuck on night
shift experience, when they wake after dark, and go to sleep after
dawn.
Person 1- "Where's Cornelius lately? I
haven't seen him in months!"
Person2- "Me neither. Since he started his new
job he's had a full-on Circadian
Backflip. He looks just like Bela Lugosi now!"