COMPREHENSIVE REVIEW OF BIORHYTHM THEORY

Biorhythm theory which became popular with the general public in the l ate 1960s held that three different biorhythm cycles influenced three different general aspects of human behavior. There was a 23-day cycle which influenced physical aspects of behavior. A 28-day cycle influenc ed emotions and a 33-day cycle influenced intellectual functions. Furt her, according to the theory, these three cycles started at birth and progressed, sinusoidally, throughout lift: varying not a bit with envi ronmental or physiological factors. This paper reviews 134 studies of biorhythm theory, both published and unpublished. 35 of those reported some support for biorhythm theory. Careful examination of these studi es identified methodological and statistical errors that account for t he claimed findings supporting the theory. Another 99 studies,covering many different variables, yielded no support. The conclusion is that biorhythm theory is not valid.