History

The classical theory originated at the turn of the 19th century, between 1897 and 1902, from observational research.

Hermann Swoboda, professor of psychology at the University of Vienna, who was researching periodic variations in fevers, looked into the possibility of a rhythmic change in mood and health. He collected data on reaction to pain, outbreak of fevers, illnesses, asthma, heart attacks, and recurrent dreams. He concluded that there was a 23-day physical cycle and a 28-day emotional cycle.

Wilhelm Fliess, a nose and throat specialist and reportedly a numerologist, was independently researching the occurrences of fevers, recurrent illnesses and deaths in his patients. He too came to the conclusion that there was a 23 and a 28-day rhythm. Fliess' theories were of great interest and importance to Sigmund Freud during his early work in developing his psychoanalytic concepts.

Alfred Teltscher, professor of engineering at the University of Innsbruck, observed that his students' good days and bad days followed a rhythmic pattern of 33 days. Teltscher found that the brain's ability to absorb, mental ability, and alertness ran in 33 day cycles. In the 1920s, Dr. Rexford Hersey (psychologist; Pennsylvania, America) also reportedly made contributions to the classical theory.

These three biorhythms compose the classical theory. The classical theory has been studied, especially in Germany, Japan, and the United States, with conflicting results. Various modern derivatives exist of the classical theory.