The human being as the nature can be described or measured by periods. The lunar cycle, the seasons, day and night, condition our destiny everyday. The "biological clock" determines the life of a person. In the Asian countries the biorhythms were known for more than 3000 years. The famous "book of changes", the I-Ching, which predicts the future and gives tips for any event is also based on the biorhythms.

The first studies about biorhythms were made in Berlin in the nineteenth century by the scientist Wilhelm Fliess. Dr. Fliess developed two basic theories: first, that the nature is manifested in the human being through "an internal clock" which starts to run from the date of birth; second, that one of those clocks regulates a cycle of 23 days that influence the physical condition and another (28 days) regulates a cycle that influence the emotions or degree of sensitivity.

Currently biorhythms can explain the reasons for that one is in good or bad mood without apparent cause, tired when it is incapable of doing nothing or feel a wave of strength to perform the better.

The theory can make possible to know with certainty when a person can get the best in their business, sports, education or even in his private life. Biorhythms are also extensively used to prevent accidents, control the health and predict the compatibility between different persons.

Each one of the biorhythms begins at birth. The cycle is divided between the active phase (above zero) and the passive one (below zero). The day or moment in which crosses from one phase to another can be seen as a critical stage, during the critical phase associated skills are unstable, it is wise to be prudent while this stage persists.

Primary cicles

The three primary cycles are:

Physical: The 23 days of the cycle monitor strength, endurance, power and health of person. Ultimately, energy, sexual and physical power.

Emotional: The 28 days of the cycle monitor stability, the positive energy of your psyche and your attitude to life, as well as the capacity to have affinity and harmony with others. Ultimately, emotions and feelings.

Intellectual: The 33 days of the cycle represent the intellectual dynamic of the person, verbal, mathematics, symbolic and creative ability, as well as the ability to implement the reason and analysis to the world around you. Ultimately, mental faculties, logic and cerebral functions.

Secondary cicles

Intuitive: The 38 days of the cycle were discovered later and cannot be regarded as a primary one. However may be useful to know what to do in case of doubt with the other cycles, as "a sixth sense". The cycle follow the tread of the unconscious perception and instincts.