Free-Running Periods

The free-running period (FRP) is the defining measure of a circadian rhythm. This video explains variations in FRP that are influenced by light intensity, and general tendencies for these variations that are referred to as Aschoff’s Rules.

Click to copy citation: Sheredos, B., Harrison, L., & Golden, S.S. [The BioClock Studio]. (2016, March 7). 1 – Free-running periods [Video file]. Retrieved from

This video was made by Ben Sheredos and Liz Harrison, two trainees at UC San Diego’s Center for Circadian Biology.