Written by Pam MS, NCSP | Fact checked by Psychology Dictionary staff 

any periodic variance in physiological or psychological operation recurring within a cycle of more than one day, like the female menstrual cycle.

ULTRADIAN RHYTHM: "The ultradian rhythm patterns will be observed and recorded in twenty females in their twenties."

More On This Topic

Link to This Definition

Did you find this definition of ULTRADIAN RHYTHM helpful? You can share it by copying the code below and adding it to your blog or web page.