The biological effects of light: focus on endocrinology

Abstract : Light is part of the electromagnetic spectrum and is compose of colors (wavelengths) that have differentiated biologic effects both at the skin level and for the effects mediated the reticulated-hypothalamic system. The secretion of the hormone-vitamin D is the most we known beneficial effect of light exposure. Many other sk, effects can be achieved with exposure to certain wavelengths. Exposure to light is an inhibitory signal of melatonin secretio but daytime exposure advances the nocturnal peak secretion and improves sleep and awakening with light exposure stimulates cortisol secretion. Changing conditions, hours of exposure to light or to specific colors can correct the effects of a sleep debt and can adapt the state of alertness. The effects of light on the gonadotropic system in the animal kingdom remain major. Only few studies are availability in humans. Phototherapy helps to treat the skin consequence of hyperandrogenism.