What are biorhythms?
Biorhythm theory says that from the moment you're born, three invisible tides begin to rise and fall within you. Each sets out from the same quiet starting line on your birthday, climbs towards a sunny high, sinks to a rainy low, and returns again for the rest of your life. Every one of us carries our own unique pattern, set on the day we arrived.
| Cycle | Rhythm | Said to govern |
|---|---|---|
| Physical | 23 days | Strength, stamina and coordination |
| Emotional | 28 days | Mood, sensitivity and creativity |
| Intellectual | 33 days | Memory, alertness and clear thinking |
Sunny highs, rainy lows and critical days
When a cycle is above the line you're in its sunny phase, when energy, mood or focus are said to flow more easily. Below the line is the rainy phase, a time to rest and recharge. The days when a cycle crosses the line are known as critical days: changeover points when biorhythm followers take a little extra care.
An idea as old as the stars
People have always sensed that life moves in tides. Long before anyone drew a biorhythm chart, ancient cultures watched for the rhythms that seemed to shape health, mood and fortune:
| Culture | The rhythm they watched |
|---|---|
| Ancient Greece | Hippocrates and his followers noticed that people had naturally "good" and "bad" days, even when they weren't ill, and recorded the body's regular cycles. |
| Traditional Chinese medicine | Health was tied to the turning of yin and yang and the flow of qi. Illness came when the body's rhythms fell out of step with the rhythms of nature. |
| Mesopotamia, Greece and Rome | Astrologers cast charts from a person's birth date, believing the turning heavens shaped body and mind. Biorhythms are often described as a modern cousin of this ancient idea. |
| The ancient world at night | Writers from Homer to Plutarch described a "first sleep" and a "second sleep", with a quiet waking hour between them for thought, prayer or reading. |
The birth of biorhythms
The modern theory began in Germany around 1900. Wilhelm Fliess, a Berlin physician and close friend of Sigmund Freud, proposed a 23-day cycle he linked to the physical body and a 28-day cycle he linked to the emotions. In the 1920s, Alfred Teltscher, a teacher in Innsbruck, noticed that his students' alertness seemed to ebb and flow, and added a 33-day intellectual cycle.
Biorhythms reached their heyday in the 1970s, when charts appeared in magazines, on pocket calculators and in mail-order kits. That's when BioKraft was born, in 1973, and now it's back.
Biorhythm compatibility
Do your highs and lows line up with someone else's? Try the biorhythm compatibility calculator with a partner, friend or colleague.
Just for fun
Biorhythms aren't supported by scientific evidence, and modern science classes them as a pseudoscience. Enjoy your chart as a playful prompt for reflection, never as medical, financial or safety advice.