Reading a chart
Threerhythms.One day.
A chart looks complex until you know what to follow. Read it in three simple moves.
01 · Follow the lines
Each line keeps its own time.
Physical repeats every 23 days, emotional every 28, intellectual every 33. Their different lengths create your pattern for the day.
Physical
Energy, strength, endurance and physical resilience.
23
one mark for every day
Emotional
Confidence, mood, creativity and emotional steadiness.
28
one mark for every day
Intellectual
Logic, memory, concentration and clear thinking.
33
one mark for every day
02 · Find the state
Eight symbols tell the whole journey.
Start at critical, rise to high, cross the middle, fall to low, then begin again. The same sequence repeats in all three cycles.
- 01
c
Critical, turning up
- 02
C
Critical, turning down
- 03
H
Full charge
- 04
L
Lowest charge
- 05
+
Charging
- 06
#
Charged, easing
- 07
-
Depleting
- 08
*
Recharging
23Physical cycleEnergy, strength, endurance and physical resilience.
One complete lap
The same eight states repeat in order. Only the number of days spent in each state changes from cycle to cycle.
| Days | Symbol | State |
|---|---|---|
| Day 1 | c | Critical, turning up |
| Days 2–6 | + | Charging |
| Day 7 | H | Full charge |
| Days 8–11 | # | Charged, easing |
| Days 12–13 | C | Critical, turning down |
| Days 14–17 | - | Depleting |
| Day 18 | L | Lowest charge |
| Days 19–23 | * | Recharging |
28Emotional cycleConfidence, mood, creativity and emotional steadiness.
One complete lap
The same eight states repeat in order. Only the number of days spent in each state changes from cycle to cycle.
| Days | Symbol | State |
|---|---|---|
| Day 1 | c | Critical, turning up |
| Days 2–7 | + | Charging |
| Day 8 | H | Full charge |
| Days 9–14 | # | Charged, easing |
| Days 15–16 | C | Critical, turning down |
| Days 17–21 | - | Depleting |
| Day 22 | L | Lowest charge |
| Days 23–28 | * | Recharging |
33Intellectual cycleLogic, memory, concentration and clear thinking.
One complete lap
The same eight states repeat in order. Only the number of days spent in each state changes from cycle to cycle.
| Days | Symbol | State |
|---|---|---|
| Day 1 | c | Critical, turning up |
| Days 2–8 | + | Charging |
| Day 9 | H | Full charge |
| Days 10–16 | # | Charged, easing |
| Days 17–18 | C | Critical, turning down |
| Days 19–25 | - | Depleting |
| Day 26 | L | Lowest charge |
| Days 27–33 | * | Recharging |
03 · Read the day
Three states become one reflection.
H
Physical
c
Emotional
+
Intellectual
BioCalendar turns the combination into a written prompt, not a prediction, just a quieter way to notice how the day feels.
512
possible combinations
8 × 8 × 8, one written reading for each.
The important part
Read the pattern. Keep your agency.
Studies that tested biorhythm theory did not find that the cycles predict anything, and a chart should be read with that in mind: as a pattern counted from your birth date, and a prompt to notice how the day feels against it. Our evidence page has what the research found.
What “critical” means
A critical day is one on which a cycle crosses its midline and changes direction. There are two in every cycle: the first day, rising, and the day part-way through where it falls below the line. The theory reads them as unsettled rather than bad. The high (H) and the low (L) are the turning points at the top and bottom. None of these is a forecast; they are positions on a counted pattern. More on critical days.
Keep reading
- What is a biorhythm?A biorhythm is a cycle said to begin at birth and repeat on a fixed period: 23 days physical, 28 emotional, 33 intellectual. The theory and the evidence.
- Critical days in biorhythm theoryA critical day is the day a biorhythm cycle crosses its midline. Which days they are in each cycle, double and triple critical days, and the evidence.
- A brief history of biorhythmBiorhythm theory from Fliess and Swoboda in the 1890s, through the 33-day cycle and the 1970s craze, to what the studies found when they tested it.