The mood depends largely on the csmell of the light we keep on at night, according to a study just published by the magazineThe Journal of Neuroscience. A) Yes,blue light is the one that most negatively affects mood, followed by white light. However, turn ona red light at night reduces depressive symptomsand helps us find ourselves in a better mood. Although the best for the mood is to sleep inthe most absolute darkness.
In their study, the scientists examined therole of photosensitive cells of the retina, ipRGCs, which, although not involved in vision, do detect lightand they send messages to the body’s circadian clock, as well as the parts of the brain responsible for regulating emotions and mood. “Night light causes certain areas of the brain to receive signals that are not generated in the dark, which may explainthe relationship between being exposed to light at night and developing depression“explained Tracy Bedrosian, co-author of the study. This phenomenon is much more evident when the light is blue than when the illumination is red, since ipRGCs cells respond unevenly to different wavelengths. To demonstrate this, the scientists worked with Siberian hamsters. And they found that, in addition to showing symptoms of depression when exposed to blue light, these rodents had a lower density of dendritic spines in the hippocampus compared to those that were in the dark. Dendritic spines are similar growths hairs on brain cells that are used to send chemical messages from one cell to another, and this anatomical change has previously been linked to depression.
The results, according to neuroscientist Randy Nelson and his colleagues at Ohio State University (USA), are applicable to humans, who among other measures should avoid the white lights of television and computers, as well as mobile phones, overnight. Also, if they use light at night when they get up to go to the bathroom or in the bedroom, they should opt for a warm or reddish light.
On the other hand, the findings have implications for people who work nights, as they are more susceptible to mood disorders. Nelson assures that,if there is no choice but to stay up all night, it is best to use red lightingin the room we occupy.
