Circadian activity rhythm influenced by near zero magnetic field

CIRCADIAN periodicity has been observed in many organisms. Motor activity, body temperature, and oxygen consumption are among the functions shown to possess a diurnal rhythm. Many of these rhythms are easily entrained to a natural or artificial cycle of light and darkness. In constant laboratory conditions of light and temperature, rhythms persist, but are slightly longer or slightly shorter than 24 h (ref. 1). The persistence of rhythms in constant conditions together with the evidence from translocation experiments 2 , are considered evidence that rhythms are endogenous. Many researchers, among them Pittendrigh 3 , Aschoff 4 , and Enright 5 , adhere to the endogenous rhythm hypothesis.