https://www.gaia.com/article/biorhythms-the-rhythm-of-life
Seasons have cycles, from amber fall days to verdant spring mornings covered in dew; day and night cycle between light and dark; the oceans swell and recede; the moon swells and thins to a crescent. If all other forms of life have inherent rhythmic cycles, are humans any different? The simple answer is, no. Whether we’re aware of it or not, humans operate on a delicate biorhythm of various cycles, from the physical, intellectual, intuitive, spiritual, to even the aesthetic.
Derived from the Greek root words, bios (life) and rhythmos (regularly occurring movement or motion), biorhythm can be thought of as the body’s holistic mathematical system that can predict, or when studied, consciously control certain aspects of one’s life such as high performance, creativity, and emotional receptivity.
Biorhythms are “invisible waves of energy within the human body that are constantly in flux.” Considered unique to each person, these energy levels are thought to begin the moment we are born. But how and when did biorhythm theory begin?
Biorhythm Beginnings: A Cosmic Harmony
While biorhythm theories have been present since ancient cultures, including those that practiced natal astrology, biorhythm theory is attributed to Wilhelm Fliess, a 19th-century German physician, and colleague of psychoanalyst Sigmund Freud. As written by Thomas Gale, Fliess’s theory is based on cycled periods – twenty-three days (physical/male), and twenty-eight days (emotional/female).
According to Gale, Fliess considered this system as a “cosmic harmony governed by the solar cycles, measured in days and years, between personal, family, and social events, but also affected by animal and plant kingdoms.” The Intellectual Cycle is attributed to Alfred Teltscher, professor of engineering at the University of Innsbruck, who added the third cycle in the 1920s, after studying the academic performance of his students.
Biorhythm theory gained in popularity in the United States and North America after two publications, This Your Day? How Biorhythm Helps You Determine Your Life Cycles, by George S. Thommen and Biorhythm — A Personal Science, by Bernard Gittelson. Today, the more modern approach has expanded biorhythm cycles for a total of six clocks, or biorhythmic periods: