biorhythm.com
Critical days in biorhythm
A critical day is a day on which a biorhythm curve crosses the centre line – switching from its high phase to its low phase, or back.
Why the zero crossings?
Biorhythm theory reads the high phase as a time full of energy and the low phase as a time of recovery. Both count as stable. The transition between them, however, is considered unstable: the rhythm is “switching over”. That is why it is the change, not the lowest point of the curve, that is seen as the most delicate moment.
How often do critical days occur?
Each cycle crosses the centre line twice per period:
- Physical: every 11.5 days
- Emotional: every 14 days
- Intellectual: every 16.5 days
Together that makes around 74 critical days a year. About five of them are double critical, because two curves change on the same day. Triple critical days are rare: in the complete biorhythm cycle of 21,252 days, a little over 58 years, there are only eight – including the day of birth.
A neat trick: the weekday you were born
The emotional cycle lasts exactly 28 days, which is exactly four weeks. Its zero crossings are therefore always 14 days apart and always fall on the weekday you were born. If you were born on a Tuesday, your emotionally critical days are always Tuesdays – every other Tuesday, for life.
What does it mean in everyday life?
Followers of the theory recommend being a little more careful on critical days: in the physical cycle during sport and in traffic, in the emotional cycle in conflicts, in the intellectual cycle with important decisions. The calculator on biorhythm.com marks critical days in the chart with a circle.
What does science say?
In the 1970s and 1980s research mainly looked at whether accidents cluster on critical days. No such link could be shown. Critical days are therefore no reason to worry – at most a prompt to pause for a moment.