There are three types of biorhythm measured

The study of biorhythms actually goes back much farther, to the 1920s when two men, Wilhelm Fliess and Hermann Swoboda, conducted extensive trials on the subject.
The theory that we are influenced by physical, emotional, and intellectual cycles is nothing new. In the 1970s, at video arcades and amusement areas in the United States, you were likely to find a biorhythm machine that provided charts based on your date of birth. Today, the Internet makes the same technology available.
The word biorhythm is composed of two Greek terms–”bios” which means life, and “rhythmos” which means a constant or periodical rhythm.

Biorhythm theory uses mostly scientific methods to chart the rhythms (cycles) that affect the internal functioning of the body and human behavior, particularly the physical, emotional and intellectual (mental) abilities.

There are three types of biorhythms measured:

1. The Ultra Radian rhythms (periods shorter that 20 hours), the most common example being the regular, short beating of the heart.

2. The Circadian rhythms (duration of between 20-28 hours). They include hormone release, body temperature and sleep.

3. The Infradian rhythm (longer than 28 hours), which includes the menstrual cycle.
The three biorhythms–physical, emotional and mental–compose the classical theory, which became popular with the general public in the late 1960s, and has been studied, especially in Germany, Japan, and the United States, with conflicting results. Two doctors, Wilhelm Fliess and Hermann Swoboda, working independently, are generally considered to be the “fathers” of biorhythm theory.

Fliess postulated a cosmic harmony governed by the solar cycles–a bi***ual periodicity, measured in days and years. He observed that people’s emotions and physical stamina changed in a regular pattern–establishing a 23-day physical (“male”) cycle and a 28-day emotional (“female”) cycle. Fliess’ theory also proposed that nature gave man a “body clock,” which measures the time from when he is born and continues throughout his life. Fliess’ theories were of great interest and importance to his contemporary, Sigmund Freud, during his early work in developing his psychoanalytic concepts.

Wilhelm Fliess (1858-1928), an ear, nose and throat surgeon from Berlin, and reportedly a numerologist, started a pioneering study on biorhythms in 1890. His work evolved through analysis of his patient’s medical records, and through having a revelation when his wife was pregnant of the theory of periods as a solution to the question of when conception occurred and the determination of the *** of the child.

Hermann Swoboda (1873-1963), a psychologist at the University of Vienna, monitored his patients’ emotional moods, dreams, creative impulses, and physical symptoms over long periods. He noted in particular that asthma attacks recurred in a regular cycle and concluded that there were two distinct cycles of 23 and 28 days, which he termed “physical” and “emotional,” respectively.

Although biorhythm theory is deemed to have been originated from research by both Fliess and Swoboda, Fliess accused Swoboda of plagiarism (on periodicity) when he learned that Swoboda had originally been told of Fliess’ work from Freud.

The combined work of Fleiss and Swoboda was developed further in the 1920s by a Viennese mathematician and professor of engineering at the University of Innsbruck, Alfred Teltscher. Teltscher observed that the brain’s mental alertness, its agility and ability to absorb, ran in regular 33-day cycles, which he called the “intellectual” cycle. Two American doctors at Pennsylvania University, Rexferd Hersey and John Bennett, also reached the same conclusion in the 1920s.

In the 1950s, Gustav Kramer and Klaus Hoffman studied the “internal clocks” of migrating birds. Further work done by Colin Pittendrigh, a British born American professor of biology, showed that the periods of internal clocks remain fixed, no matter what happens to the surrounding environment.

In the early 2000s, Zerrin Hodgkins, a London based researcher, and Michael Smolensky, University of Texas, both concluded that the emotional cycle plays across 21 days, not 28, and that a fourth strand to the biorhythmic pattern, renamed “reflexive” cycle, simply represents the autonomic nervous system, which controls automatic functions, reactions and reflexes.

With miscellaneous points of research, and differing perspectives, and even with biorhythm charts now easily displayed using computer software technology, biorhythm theory still remains a theory.

Various modern derivatives also exist of the classical theory and further work has revealed other cycles, namely a 38-day intuitive cycle, a 43-day aesthetic cycle and a 53-day spiritual cycle.

Although Fliess and Swoboda are given recognition as the fathers of biorhythm theory, the earliest observed biological cycles were recorded by Alexander the Great’s scribe, Androsthenes, in the fourth century BC. Then, in 1729, the first known experiment on biological rhythms was performed by Jean Jacques d’Ortous de Mairan, a French astronomer. He investigated the behavior of heliotrope, a plant with leaves that open during the day and close at night. He found that the leaves continued to open and close even when lighting levels were constant.

In the 1930s, scientists noticed that bees collected pollen at regular times, even when nectar and daylight were absent. This was an important indication that endogenous rhythms applied to all organisms with a central nervous system.