The three cycles

Physical cycle

Definition

The physical cycle is the shortest of the three biorhythm cycles: it lasts 23 days and starts on the day of birth. The classic method links it to energy, stamina and drive. It spends eleven days in the high phase and eleven in the low one, with a critical day at each crossing between the two.

It is the cycle Wilhelm Fliess described first, in 1897, and called the male cycle. In the classic method it governs the most concrete side of a day: the strength available, endurance under effort, the readiness of reflexes.

With a 23-day period it is also the cycle that changes phase most often: a critical day roughly every eleven and a half days. Of the three, it is the one people tend to notice first when they compare the chart with how they feel.

A worked example with real numbers

For someone born on 15 June 1990, on 2 September 2026 the physical cycle is on day 4 of 23: in the first half of the cycle, so in the high phase.

Frequently asked questions

What changes between the high and the low phase of the physical cycle?

In the high phase the method places the days when strength and stamina respond best; in the low phase the days for recovery. They are two equal halves of the cycle, not a reward and a punishment.

How often does a physical critical day come round?

Twice per cycle, so roughly every eleven and a half days: when the cycle starts and when it crosses from the high phase to the low one.

Physical cycle

Related terms

Frequently asked questions