Before revision: 250px|Biorhythm chart over the first 66-day period after birth: The biorhythm theory is the pseudoscientific idea that peoples' daily lives are significantly affected by rhythmic cycles with periods of exactly 23, 28 and 33 days,.. typically a 23-day physical cycle, a 28-day emotional cycle, and a 33-day intellectual cycle.
After revision: 250px|Biorhythm chart over the first 66-day period after birth: The biorhythm theory is the idea that peoples' daily lives are significantly affected by rhythmic cycles with periods of exactly 23, 28 and 33 days,.. typically a 23-day physical cycle, a 28-day emotional cycle, and a 33-day intellectual cycle.