A circadian rhythm is a roughly-24-hour cycle in the biochemical, physiological or behavioral processes of living entities. The term "circadian", coined by Franz Halberg,[1] comes from the Latin circa, "around," and diem or dies, "day", meaning literally "approximately one day."
Lighting levels that affect circadian rhythm in humans are higher than the levels usually used in artificial lighting in homes. According to some researchers[21] the illumination intensity that excites the circadian system has to reach up to 1000 lux striking the retina. In addition to light intensity, wavelength (or color) of light is a factor in the entrainment of the body clock. Melanopsin is most efficiently excited by blue light, 420-440 nm[22] according to some researchers while others have reported 470-485 nm.
It is thought that the direction of the light may have an effect on entraining the circadian rhythm;[21] light coming from above, resembling an image of a bright sky, has greater effect than light entering our eyes from below.
(all images by me except the David LaChapelle photo-duh!)
It never fails to awe me, how sickeningly cyclical our bodies are, how inseparable the without and the within, the above and below are.
ReplyDeleteThats interesting about the light. I've read different articles and theories about light and how humans have become so bombarded with artifical light over the past few hundred years, and the effects its had on our sleeping patterns. I can only wonder what kind of dreams and rich night lives the ancients had when darkness and light were on more equal planes.