(Investigator 131, 2010 March)

Biofeedback (Investigator 129) was concerned with the wave patterns caused by the electrical activity of the human brain, their detection, and the use to which the output can be put. However, the cyclic patterns which we see displayed on an EEG are only a small part of the overall rhythmic behaviour determinants of man and the universe; there are many more that influence our being and daily lives.

The daily cycle of sleep and wakefulness for example, the rise and fall of the tides determined by the moon's phases, the 28 day menstrual cycle in females and the annual migration of birds to mention a few. One important discovery, attributed to the famous psychiatrist Sigmund Freud, and in particular his associates Dr Wilhelm Fliess and pychologist Dr Hermann Swoboda, was the science of Biorhythms.

Like biological clocks, they reasoned, biorhythms determine from the time of birth the cyclical ups and downs in an individual's life. There is a 23 day physical cycle that influences strength, stamina, energy output and self-reliance. A 28 day emotional cycle indicates the extent to which one has control over daily emotional conflicts and a 33 day intellectual cycle important in those areas requiring mental activity. The latter was added by a contemporary researcher, Alfred Teltcher.

Each cycle begins at the time of birth, and rises and falls regularly throughout one's life, repeating itself only once in 53 years. When charted, the high peaks are considered to be the most productive, the troughs when we are at our lowest ebb. When the cycles are changing from high to low and vice versa they are known as 'critical days' and are indicative of unstable times when one is prone to accident.

Supporting the theory, are the calculations involved to determine one's biorhythmic ups and downs.

These are alleged to be numerologically efficient and very simple to use, and a variety of charts, literature and electronic calculating devices are available on the market. The ability of biorhythms to predict the most propitious days for human performance has been confirmed it is claimed by researchers in many areas, and its potential to prevent accidents and save lives is well documented.

One scientifically validated study of biorhythms (Thommen 1973) shows that 60 per cent of accidents are caused by human error on 'critical' days; another by the Canadian Armed Forces came to the same conclusion in a 7,000 case history study, and industrial firms in Japan and Sweden have testified to a reduction of accidents when employees were made aware of pending 'critical' days ascertained from the employees' individual biocurve charts.

Terms such as "biorhythm" are standard in the biological literature with a substantial experimental base, however, the aspect being dealt with here is its use for a less defensible purpose.

The claim has been made that the science of biorhythms was established by Sigmund Freud and his close friend Dr Wilhelm Fliess, but while Freud's letters to Fliess are available for perusal nothing attributable to Fliess exists. According to Daniel Cohen in his book, Biorhythms in Your Life, Fliess' medical and scientific colleagues not only ignored his book but attacked his ideas and the statistics upon which they were based.

The basic premise of the biorhythms theory is found wanting when subjected to critical assessment. The advocates of biorhythms support their case with selective sampling and apply after-the-fact rationalization of the data to confirm its accuracy. Scientifically controlled tests however, paint an entirely different picture and give absolutely no empirical support to the theory. In 1981, one such study carried out by Dr Brian Quigley, Senior Lecturer in the Department of Human Movement Studies at the University of Queensland, involved the alleged relationship between biorhythms and sport. Dr Quigley made a study of all world record breaking male athletes in track and field events from 1913 to 1977. He found that the evidence for biorhythms consisted of retrospective anecdotal accounts of selected events, name dropping, a lack of definition of terms, and inadequate details of methods, data and statistical analysis. His findings were presented at the 26th Annual Meeting of the American College of Sports medicine and Pan-American Conference.

Encyclopedias are available in any large book stores which contain all the information necessary to test the theory — the birth dates, wins and losses, of sports stars and other well known public figures and these can be used to check out the biorhythm theory. Those who have done so show that the figures are no different than would be expected by chance. In addition to selectivity, the placebo or expectancy effect widely known in medicine and psychological therapies might also be the basis for some of the claims made by biorhythm proponents.

If it is indeed true that such cycles exist, and this itself is dubious, then the cycles can only be population averages. It is therefore unlikely that any given individual would have a cycle matching the average, yet this is precisely what biorhythm promoters seem to do, a patently absurd concept.


Bainbridge, William S. 1988. "Biorhythms: Evaluating a Pseudoscience." Skeptical Inquirer. 2(2): 40-56. CSICOP.

Fix, A. James. 1976. "Biorhythms and Sports Performance." Skeptical Inquirer. 1(1): 53-57. CSICOP.

Gardner, Martin. 1984. "Freud and Fleiss." Skeptical Inquirer. 8:302¬304. CSICOP. Buffalo, NY.

Gittleson, Bernard. 1978. Biorhythm. Futura. London.

James, A. 1984. 'The Validity of Biorhythmic Theory Questioned." British Journal of Psychology. 75, 197-200.

Muallardi, V. 1978. Biorhythms and Your Behaviour. Running Press.

Thommen, George S. 1973. Is This Your Day? Avon. New York.

Quigley, Dr Brian. 1981. "Biorhythms Cause Australian - N.Z. Tensions. the Skeptic, 1(1):2.

From: Edwards, H. A Skeptic's Guide to the New Age.