Certina Biostar Eletronic NOS ref.7301 001
For people who want to know if they are having a good day or a bad day, at the beginning of the 20th century the Austrian psychologist Hermann Swoboda and the Berlin doctor Wilhelm Fliess brought the idea of biorhythms into being. The biorhythm is a scientifically unconfirmed theory that claims that one’s life is affected by rhythmic biological cycles and therefore can be calculated. These inherent rhythms are classically composed of three cyclic rhythms: the physical, having a duration of 23 days; the emotional (28 days); and the mental (33 days). The biorhythm became popular in the 1980s, when due to the first programmable calculators and personal computers, it was possible to easily calculate one’s biorhythms oneself. In 1965, Certina had brought the Biostar to market. It was the first (and as far as I know the only) wristwatch from which you could read your biorhythm.