There are three cycles that are considered to rule our behavior, the physical, emotional and intellectual.
Some scientists believe there is a fourth - intuitional.
These body cycles are know as biorhythms. Each of these cycles starts at the time of birth. From this point, each of the cycles starts to rise up through its active phase until it falls back to the passive phase. Then it raises to begin all over again. In the active phase the abilities associated with the particular cycle are high.