[Hadrian (OP)]

I heard that in port of Odessa in the former U.S.S.R workers were not given any work on their critical days to avoid accidents.

Apparently the critical days were determined by following:
they said, that in a humans there is a physical cycle is of 23 days ; and intellectual , of 33 days . Critical days are those days on which there is transition from one phase to another

Has anyone ever herd of this and is it true?

[Bored chemist]

Plenty of people have heard of it. As far as I know it has the same sort of following as astrology and about the same "success" rate.
http://en.wikipedia.org/wiki/Biorhythm

[Hadrian (OP)]

Plenty of people have heard of it. As far as I know it has the same sort of following as astrology and about the same "success" rate.
http://en.wikipedia.org/wiki/Biorhythm

and did the port of Odessa in the former U.S.S.R give workers time off for it?