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What Are Biorhythms?

Biorhythm theory proposes that aspects of a person's life follow repeating cycles beginning at birth.

The classic model uses three sine-wave cycles: a 23-day physical cycle, 28-day emotional cycle, and 33-day intellectual cycle. A calculator can plot these mathematically from a birth date.

Evidence note: the existence of the mathematical waves is not evidence that they predict health, ability, mood, accidents, or future events. Biorhythm theory is not scientifically established.

Explore the classic cycles

Physical · Emotional · Intellectual

Try the free calculator