title: Protecting the melatonin rhythm through circadian healthy light exposure.
abstract: Currently, in developed countries, nights are excessively illuminated (light at night), whereas daytime is mainly spent indoors, and thus people are exposed to much lower light intensities than under natural conditions. In spite of the positive impact of artificial light, we pay a price for the easy access to light during the night: disorganization of our circadian system or chronodisruption (CD), including perturbations in melatonin rhythm. Epidemiological studies show that CD is associated with an increased incidence of diabetes, obesity, heart disease, cognitive and affective impairment, premature aging and some types of cancer. Knowledge of retinal photoreceptors and the discovery of melanopsin in some ganglion cells demonstrate that light intensity, timing and spectrum must be considered to keep the biological clock properly entrained. Importantly, not all wavelengths of light are equally chronodisrupting. Blue light, which is particularly beneficial during the daytime, seems to be more disruptive at night, and induces the strongest melatonin inhibition. Nocturnal blue light exposure is currently increasing, due to the proliferation of energy-efficient lighting (LEDs) and electronic devices. Thus, the development of lighting systems that preserve the melatonin rhythm could reduce the health risks induced by chronodisruption. This review addresses the state of the art regarding the crosstalk between light and the circadian system.
authors.affiliation: Department of Physiology, Faculty of Biology, University of Murcia, Murcia 30100, Spain. mbc11365@um.es.
authors.forename: Maria Angeles
authors.initials: MA
authors.lastname: Bonmati-Carrion
authors.affiliation: Department of Physiology, Faculty of Biology, University of Murcia, Murcia 30100, Spain. raquel.arguelles@um.es.
authors.forename: Raquel
authors.initials: R
authors.lastname: Arguelles-Prieto
authors.affiliation: Department of Physiology, Faculty of Biology, University of Murcia, Murcia 30100, Spain. mj.martinezmadrid@um.es.
authors.forename: Maria Jose
authors.initials: MJ
authors.lastname: Martinez-Madrid
authors.affiliation: Department of Cellular and Structural Biology, University of Texas Health Science Center, San Antonio, TX 78229, USA. REITER@uthscsa.edu.
authors.forename: Russel
authors.initials: R
authors.lastname: Reiter
authors.affiliation: Johann Friedrich Blumenbach Institute of Zoology and Anthropology, University of Göttingen, Göttingen 37073, Germany. rhardel@gwdg.de.
authors.forename: Ruediger
authors.initials: R
authors.lastname: Hardeland
authors.affiliation: Department of Physiology, Faculty of Biology, University of Murcia, Murcia 30100, Spain. angerol@um.es.
authors.forename: Maria Angeles
authors.initials: MA
authors.lastname: Rol
authors.affiliation: Department of Physiology, Faculty of Biology, University of Murcia, Murcia 30100, Spain. jamadrid@um.es.
authors.forename: Juan Antonio
authors.initials: JA
authors.lastname: Madrid
mesh_terms: D000818:Animals; D002940:Circadian Rhythm / Q000502:physiology*; D006262:Health; D006801:Humans; D008027:Light; D008029:Lighting; D008550:Melatonin / Q000502:physiology*; D017440:Photoperiod; D012160:Retina / Q000502:physiology
chemical_list: D008550:Melatonin