Biorhythm: Science or Fiction?


“Today is just not my day!” How many times have you heard that? The fact is that we all have our ups and downs, our “good” and our “off” days. If your observations confirm such subtle changes in vitality and emotions, then you have become aware of your own Biorhythms, the rhythmical influences creating the tides in your life.

Now, with the aid of computer technology, it is possible to chart the Biorhythms of everyone in the world, provided that they know the date of their birth. It is a forecast of the changes in your physical, emotional, and intellectual state. Thus armed, you will be forewarned of your off days, you will know when they are coming, and will know when to STOP, LOOK and LISTEN before you act. You will also know the exact dates when your glorious good days are awaiting you; the days when you’ll have that tireless extra energy and mental and emotional control over yourself. You will know ahead of time, the days when your creative talents come to the surface, so that you can prepare ahead and buckle down to accomplish what you set out to do.

Biorhythms have only been the subject of research since the early 1900’s, the ups and downs or cycles in our lives are a well known fact. The earliest reports come from the fields of medicine and psychology where a 23-day high and low tide in physical resistance and a 28-day high and low affecting the nervous system was discovered. During each change of phase, the researchers noted, man’s physical and mental state experiences a period of instability that lasts  about a day. These days were called “critical” or “off” days because a surprising increase in the outbreak of an illness, in mental depression and in human-error failure and accidents were reported during those days.

Theory and Practice

The theory behind biorhythm is quite easy to understand. From birth to death each of us is influenced by three internal cycles – the physical, the emotional, and the intellectual.

  • The physical cycle is 23 days long and it influences a broad range of physical factors such as resistance to disease, strength, co-ordination, speed, physiology, endurance, and the sensation of physical well-being.
  • The emotional cycle last 28 days and governs creativity, sensitivity, mental health:love/hate, optimism/pessimism/ passion/coldness, depression/elation, mood, and perceptions of the world and ourselves.
  • The intellectual cycle, which takes place over a 33-day period, regulates memory, alertness, receptivity to knowledge, and the logical or analytical functions of the mind: reasoning ability, accuracy of computations.
  • The intuitional cycle, which takes place over a 38-day period affects our unconscious perception, hunches, instincts, sixth sense.

On the day of birth, each cycle starts at a neutral baseline or zero point and begins to rise in a positive phase, during which the energies and abilities are high. Gradually declining the cycles cross the zero point midway through their complete periods – 11 1/2 days from the point of origin for the 23-day physical cycle, 14 days for the 28-day emotional cycle, 16 1/2 days for the 33-day intellectual cycle and 19 days for the 38-day intuitional cycle. The remainder of each cycle is in a negative phase in which energies are recharged and our physical, emotional, and intellectual capabilities are low, or at least somewhat diminished. We pick up increasing amounts of energy as the negative phase continues until, at the end of each cycle, the zero point is recrossed into the positive phase, and the whole process begins again.

Biorhythms tend to affect behavior in a peculiar way. Our weakest and most vulnerable days are not those of the negative phase, as you might suspect. Rather they happen when each cycle crosses the base line, switching from positive to negative or visa versa, and it is at these times that we can expect ourselves to be in the most danger. It seems that a on these days the rhythms that affect us – and on whose regularity we depend as much as on the steady pulse of the heart – are very unstable. They are temporarily out of step. These cross-over days from one phase into another are called “critical days”. During these days abilities vary wildly, from extremely high to extremely low.

  • On physical critical days we are most likely to have accidents, catch a cold, and suffer all types of bodily harm. You may win the Super Bowl, or throw 10 interceptions on a physical critical day.
  • Quarrels, fights, depression, and senseless frustration are typical of emotionally critical days. You may impulsively propose marriage or impulsively quit your job on an emotionally critical day.
  • On intellectual critical days, we can expect bad judgement, difficulty in expressing things clearly, and a general resistance to learning anything new or remembering what we already know. You may make brilliant discoveries or tragic logical errors on intellectual critical days.

The point is that by calculating and studying biorhythms in advance, you can know what to expect and can do much to avoid the worst. For example, businessmen familiar with biorhythm can make a point of refusing to sign crucial contracts on emotionally and (especially) intellectually critical days. Athletes in all sports are well-advised to play with extra care – or to avoid play altogether – on physically critical days, when they are very vulnerable to injury. All of us could avoid unnecessary arguments simply by exerting a little more self-control on emotionally critical days. Days when not one, but two or all three cycles are critical require special attention – although probably not ot the extent practiced by one follower of biorhythm, who swears that on triply critical days he stays in bed and tries not to move, feel, or think at all!

Planning ahead for critical days may be the most valuable use of biorhythm, since this can literally make the difference between life and death. But only 20 % of the days in your life are critical days, the other 80% are mixed days, whose character is very varied. You can plan your future to harmonize with your biorhythms for non-critical days. It makes sense, for instance, to try to set records on days when all three cycles are near their peaks and you have as much energy and ability as possible. Conversely, knowing that all three cycles are near the bottom of their negative phases is a clear indication that you cannot count on turning in an outstanding performance.

Can You Prove It?

That’s the first question that is asked. It is often difficult to proof that a death due to an illness occurred because of the critical day or because of the illness. However, studies have been done in retrospect to car accidents. In one such study in Missouri 100 fatal single-car accidents, in which the driver died, were studied and the findings were remarkable. “The study found that 46% of those fatalities had occurred on a critical day, and another 11% had happened within 24 hours of a critical day, for a total of 57%. More than half the the single-car fatalities happened on emotionally critical days, or when the driver had a combination of an emotional critical day with a critical day in one of the other two rhythms”. “Studies done in Japan by the Japanese Military Police came up with similar findings. “65% of the accidents happened on critical days, 66% of those that involved drunken driving happened on critical days.” A percentage much higher than one would normally assume.

Airplane accidents also offer an excellent opportunity for biorhythm research. There is a flight recorder and the findings of the accident are very detailed, so there is definite proof of pilot error or mechanical fault. The results of such research state that around 50% of accidents occurred on pilot’s critical days or double critical days when two rhythms crossed the baseline at the same time.

Rhythm While You Work

While the influence of biorhythms in airplane accidents is impressive and dramatic, even more startling is the evidence that has come from retrospective studies of how biorhythms affect industrial accidents.

In studying the relationship between biorhythm, and on-the-job accidents, researchers run into the same problems they face with all other kinds of accidents: i.e. determining when an accident was caused mainly by human factors, and when it was largely the result of unsafe working conditions or mechanical failures. Fortunately, almost all lost-time industrial accidents are reported on insurance and compensation forms, so it is relatively easy to pick out the human error accidents. One study done in the US covered over 300 accidents in four different settings: a metal working plant, a chemical plant, a textile mill, and a knitting mill. Almost 70% of the accidents had happened on a critical day of the victims cycle. The most accidents happened when two rhythms crossed each other at the baseline or zero point, or just below that point. In other words, when two rhythms are moving in opposite directions (when the physical rhythm is switching from positive to negative while the emotional rhythm is moving up from negative to positive, for example) and they cross when both are in critical or very close to critical. Out of that study the following three conclusions were drawn:

  • “An individual will show marked changes during critical days.”
  • “When an accident occurs on a critical day and the individual does not know that is was a critical day, he is unable to explain why the accident happened.”
  • “The individual’s physical abilities, mental capacity, and emotional tone all reflect critical days in relatively obvious ways.”

It seems that 50-70% of accidents happen on critical days which is much higher than probability would predict.

Examples from the Sporting Life

A sample given in the book “Biorhythm, A Personal Science, by Bernard Gittelson” is Muhammed Ali’s March 31, 1973 fight with Ken Norton. Ali was suffering from a critical day in both his physical and emotional rhythms. So his loss was no surprise to anyone who figured out Ali’s biorhythms. On September 25, 1974 Ali fought George Foreman in Zaire and won. Foreman was going through a physical low on the 26th, one day after the fight, and he was to come out of an emotional low and into a critical day. Ali on the other hand was high in both the physical and emotional rhythms, a situation that undoubtedly helped him succeed.”

“Retrospective analyses of baseball players also provide examples of biorhythm’s importance to athletic performance. In 1927 Babe Ruth set a new record by driving in 60 home runs in one season. Analysis shows that all but 13 of those home runs were hit on days when Ruth was at or near a physical or emotional peak, that 79% of the time.

During the ten days in August of the Olympics in 1972 when Mark Spitz won 7 gold medals in swimming, he was in a physically and emotionally high period during all ten days.

Biorhythms can effect us in any situation in life. Is Johnny going to be a war hero or a deserter? Again retroactive studies found that soldiers are more likely to perform heroic acts,  or deserts or commit suicide during critical days.

Are students also affected by biorhythms? Is there a time when we can more likely put in a A performance than a D? Here also studies show that students taking exams are more likely to do extremely well on days when their intellectual cycle is in the positive phase.

Do Companies use Biorhythms in Scheduling their Labor Force?

Airline companies are using biorhythm to arrange Pilots’ schedules. Swissair is one of those airlines that has been studying the critical days of its pilots for a long time. When either a pilot or co-pilot is experiencing a critical day, he is not allowed to fly with another experiencing the same kind of instability. As a result of this Swissair has no reported accidents on the flights to which biorhythm has been applied.

Biorhythm and Your Health

Given all the information shown so far, it seems only logical to apply biorhythms also to the medical field. Would knowing your biorhythm help you get over an operation more quickly? Chances are that recovery from an operation performed during the positive phase of especially the physical cycle will be much faster than an operation performed during the negative phase of the same cycle. Only emergency operations should take place during the negative phase of a cycle. If ever possible don’t have an operation on a critical day, no matter which one it is.

Biorhythms do affect our lives, if we are aware of them or not. So to help us in our personal, and business life knowledge of our own biorhythm profile can only add a positive dimension to it.


Gittelson, Bernard, Biorhythm, A  Personal Science.
1975 Arco Publishing Company, Inc. New York, NY.


biorhythm calculators links



Biorhythm: Science or Fiction? — 6 Comments

  1. What does it mean when I have a triple critical aspect right on my birthday, December 25th??? All but the intellect are on the critical line!

    • Beya, it means that you should be extra careful on that day, as you could be clumsy, but intellectually you will be fine. So don’t do too much.

  2. Pingback: Do your natural rhythms affect your performance? | Lyndi Smith

  3. In the late 70s when I was in college, a classmate of mine and I ordered a biorhythm calculator (this of course was before the days of the Internet!). Using the local hospitals records, we did research on date of birth according to birth order as the baby’s birthday related to the mother’s birthdate. I don’t remember the results, but whatever they were, they were surprisingly predictive.

    Remembering the date of the date where I crashed my car into a tree after becoming air borne and spinning around at 65 mph, knocking the tree over in the process–probably the only thing saving my life–, I discovered that the accident occurred on a triple low, which I believe only happen one to three times a year on average. That was a real wake up call and confirmed what we were seeing in our results.

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