were a fascination of mine in the 70's. The premise is that when a person is born, three basic cycles begins. They relate to the person's physical, intellectual, and emotional states that rise and fall based on a given cycle of days.
Each cycle has a high, low, and critical point that can be compared to anothers biorhythm. Followers of this psuedoscience
would schedule their days based on the state of their specific biorhythm.