Circadian rhythm in humans

Background: Chronobiology is a field of science that examines periodic (cyclic) phenomena in living organisms and their adaptation to solar and lunar related rhythms. These rhythms have frequencies lasting from milliseconds to years. Some biological rhythms depend on the events in the environment. Th ese include alternations of day and night, changes in environment temperature and changes of seasons. Research in the last few years showed the importance of biological rhythms for the human health and well being. Th e most widely investigated biological rhythm is the circadian rhythm which has a period of approximately 24 h. Conclusions: Chronobiology and chronomedicine are becoming important fields in understanding the functions of the human body. Another emerging field of science is chronopharmacology whose main objective is to elucidate the time points at which drugs will be most effective and will have the least side effects.