Now whether you believe in biorhythms or not is a personal prerogative. Being aware of them in my life seems to work for me, and has for the past 30+ years.
There is a very complete article in Wikipedia:
“The theory of biorhythms claims that one's life is affected by rhythmic biological cycles, and seeks to make predictions regarding these cycles and the personal ease of carrying out tasks related to the cycles. These inherent rhythms are said to control or initiate various biological processes and are classically composed of three cyclic rhythms that are said to govern human behaviour and demonstrate innate periodicity in natural physiological change: the physical, the emotional, and the intellectual (or mental) cycles. Others claim there are additional rhythms, some of which may be combinations of the three primary cycles. Some proponents think that biorhythms may be potentially related to bioelectricity and its interactions in the body."
The natural world is teeming with regular patterns and sequential events that can be represented mathematically. Our ancestors had no difficulty spotting daily (circadian) and yearly (annual) rhythms in plants, in animals, and in themselves.
— Earliest observed biological cycles were recorded by Alexander the Great's scribe, Androsthenes, in the fourth century BC.
— Jean Jacques d'Ortous deMairan, a French astronomer, performed the first known experiment on biological rhythms in 1729. 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 late 1800s and early 1900s two doctors were instrumental in the study of biorhythm and are now considered to be the “fathers” of biorhythm theory. Dr. Hermann Swoboda, a Professor of Psychology at the University of Vienna and Dr. Wilhelm Fliess an ear, nose and throat surgeon from Berlin (and a contemporary and colleague of Siegmund Freud) observed that people's emotions and physical stamina changed in a regular pattern. Their great contribution to chronobiology was to establish the 28-day emotional and the 23-day physical cycles.
— The third and intellectual biorhythm cycle was first proposed in the early twentieth century by a Viennese engineer and mathematician called Alfred Teltscher. He observed that humans had a regular 33-day cycle for mental agility and ability. Two American doctors, Rexferd Hersey and John Bennett, reached the same conclusion independently at Pennsylvania University.
These cycles start the moment we are born. They are at a mid-point at that time. They then go up and down at different rates over our lifetimes. When any of the cycles are at a high point, things we do that require aspects of that trait are more successful - the reverse is true during the low points of a cycle. Many people report that they can improve the quality of their lives by monitoring their biorhythms and acting accordingly.
All three cycles go through positive (ascending) and negative (descending) phases. The days on which a cycle passes from positive to negative or vice versa are known as "critical" days.
There are three critical days in each cycle, and it has been proven statistically that more accidents happen on these days than at any other point in the cycle. Many Japanese corporations provide their staff with biorhythm calculations in order to promote efficiency in the workplace.
I check my biorhythm cycle upon occasion making a mental note of when critical days will occur. There are a number of biorhythm software programs on the internet, some for a nominal fee and others are free.
