Biorhythm second birth
The biorhythm second birth is the day on which all three biorhythm cycles return together to their starting point, as on the day of birth. It happens every 21,252 days, the least common multiple of 23, 28 and 33: about 58 years and two months. From there the combination of the three cycles starts over identically.
Three cycles of different lengths realign only when the number of days lived is a multiple of all three. The first such number is 23 times 28 times 33, that is 21,252. This is why in most lives the second birth happens once, around 58, and a possible third at 116.
It is not a special event in the horoscope sense: it is an arithmetic fact. But it is a concrete way to see that the combination of the three cycles stays unique for a long time, and that two people with different birth dates rarely repeat it.
For someone born on 15 June 1990, on 2 September 2026 there are 8,023 days to go until the second birth: just under twenty-two years.