I remember for a few years in the late ‘70s were a huge deal. And I’d say taken more seriously by some than just horoscope superstition.
https://www.vice.com/en/article/biorhythms-the-1970s-fad-that-won-a-super-bowl-killed-clark-gable-and-made-america-gaga-for-computers/
For a while in the 1970s, these charts were everywhere. Las Vegas bookmakers like Jimmy “the Greek” Snyder factored them into betting lines. Newspapers routinely interviewed experts to see how biorhythms would play out in big games and even big elections. The ability to draw up these charts for yourself was a major selling point for the earliest personal computers. The first team to exploit computerized scouting, the Dallas Cowboys, was also the club most heavily invested in biorhythms. All of which leads to a question: How did they get so big, and how could a tool with this much supposed explanatory power disappear so completely?
Gamblers got the idea—and newspapers found it useful as well. Suddenly, sports pages were running headlines like “Biorhythms Favor Dallas,” “Biorhythms: Dodgers Must Win in 5—or Lose in 7,” and “Stabler’s Biorhythms Portend Raider Win.” The last story went on to note, “Bio-stat finds Ken Stabler peaking on physical cycle … and pluses in emotional and intellectual cycles. Franco Harris’ bio-stat finds a minus physically, a plus emotionally and a minus intellectually. Terry Bradshaw just passed through a physically critical day Saturday before the game.”