The three cycles
The physical cycle is the shortest of the three, 23 days from one critical day to the next. The theory says it governs energy, strength and endurance. Here is how it is counted and read.
23days
The theory assigns the physical cycle energy, strength, stamina and coordination: the high phase as a time of vigour and quick recovery, the low phase as a time to rest, the critical days as unsettled. It is the cycle people most often check before something physical, a race, a long day, a game.
The physical cycle begins on the day you were born and repeats every 23 days. To find where it sits on any date, count the days since your birth, divide by 23, and the remainder is the day of the cycle; the day you were born is day 1. That is the whole calculation, and it is the same for everyone.
Step by step, with a worked example: How to calculate a biorhythm.
Eight states
The symbols and their meanings are explained on How to read a biorhythm chart.
Day 1
Critical, turning up
Days 12–13
Critical, turning down
Day 1, when the cycle begins and rises through its midline, and the day about half-way through, when it falls below it. The theory reads both as unsettled rather than bad: days to notice how you feel. Critical days, explained.
BioCalendar
In BioCalendar the physical cycle is drawn in amber. The home screen shows which of the eight states it is in today and the day number; the calendar shows the symbol for every date; and goals that have a physical side, like fitness or sleep, use it to mark the stretches of the month above the midline.
The record
Studies that looked for this cycle in the things it is said to govern did not find it. We set out the research on Are biorhythms real?, and we ask you to read the cycle the way BioCalendar presents it: as a counted pattern, and a prompt to notice the day, not a forecast.
