Biorhythm (pseudoscience)

According to the notion of biorhythms, a person's life is influenced by rhythmic biological cycles that affect his or her ability in various domains, such as mental, physical, and emotional activity.

It is built on the idea that the biofeedback chemical and hormonal secretion functions within the body could show a sinusoidal behavior over time.

There is no particular meaning to a day on which one's rhythms are all high or all low, except the obvious benefits or hindrances that these rare extremes are thought to have on one's life.

The 23- and 28-day rhythms used by biorhythmists were first devised in the late 19th century by Wilhelm Fliess, a Berlin physician and friend of Sigmund Freud.

[5] One of the first academic researchers of biorhythms was Estonian-born Nikolai Pärna, who published a book in German called Rhythm, Life and Creation in 1923.

(from Carroll's The Skeptic's Dictionary)[4]: 175 The physiologist Gordon Stein in the book Encyclopedia of Hoaxes (1993) wrote:[10]Both the theoretical underpinning and the practical scientific verification of biorhythm theory are lacking.

They are hoaxers of the public if they know what they are saying has no factual justification.A 1978 study of the incidence of industrial accidents found neither empirical nor theoretical support for the biorhythm model.

[12] This kind of willful credulous belief in vague or inaccurate prognostication derives from motivated reasoning backed up by fallacious acceptance of confirmation bias, post hoc rationalization, and suggestibility.

[5] Wilhelm Fliess "was able to impose his number patterns on virtually everything"[13] and worked to convince others that cycles happen within men and women every 23 and 28 days.

[17] Assuming such factors were relevant to biorhythms would result in chaotic cycle combinations that remove any "predictive" features.

[18] In order to test his hypotheses, James observed 368 participants, noting their performance on tasks associated with intellectual, physical, and emotional functioning.

Based on data collected from his experimental research, James concluded that there was no relation between subjects' biorhythmic status (on any of the three cycle types), and their performance on the associated practical tests.