n. a biological cycle which alternates between periods of wakefulness and sleep - or in other words, activity and non-activity. Typically, it goes in rhythm with your human biological clock, and it cycles every 80 to 120 minutes (90 minutes on the average).

BASIC REST-ACTIVITY CYCLE (BRAC): "The Basic Rest-Activity Cycle (BRAC) is a transition from different levels of excitable to restful states and then back."
Cite this page: N., Pam M.S., "BASIC REST-ACTIVITY CYCLE (BRAC)," in, April 7, 2013, (accessed April 17, 2021).