Biorhythms - periodicity in living systems

Biorhythms consist of biological events or functions that reoccur in time in a repeated order and with a regular interval between occurrences. The aim of this paper is to summarise some of the major biorhythms in living systems and the human body, examine briefly the mechanisms of operation of electrophysiological rhythms and accordingly speculate on the possibilities of subtle, low energy, non-thermal effects under the influence of weak electromagnetic radiation.