ultradian [uhl-trey-dee-uh n]
1. of or relating to a biorhythm having a period of less than 24 hours.
Origin: 1960–65; ultra- + Latin di(ēs) day + -an
1. Relating to or exhibiting periodic physiological activity that occurs more than once every 24 hours.
Now YOU come up with a sentence (or fic? or graphic?) that best illustrates the word.