[Effect of solar activity on the physiological rhythms of biological systems].

The infradian components, including those with a period of about 3.5, 7, 30 days, are ubiquitously found in biology, from unicells to complex biological organisms. It can be hypothesized that heliogeophysical factors other than the solar visible light, likely at the origin of the circadian system (with a period of about 24 hours), may be responsible for the infradian biosystems.