According to INSERM, one in three French adults are affected by a sleep disorder. This increases with aging, although the biological mechanisms at the origin of this disorder remain unknown. However, a study brings to light a new hypothesis.
New research, carried out by Claude Gronfier, Inserm researcher, and his team at the Lyon Neuroscience Research Center, hypothesizes that the appearance of sleep disorders during aging is linked to a decline in the perception of light. . Which disrupts the biological clock.
Sleep disorders linked to aging
Sleep problems increase with age. Studies show that nearly a third of people over 65 use sleeping pills chronically. Despite these data, no previous study has focused on the factors that cause sleep disorders in the elderly.
The team from the Lyon Neuroscience Research Center looked into the question, exploring the possibility of a potential problem with light perception. As a result, scientists observed the effects of light on the secretion of melatonin in a group of adults. To do this, participants were exposed to 9 lights of different colors in order to better identify the mechanisms involved.
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Exposure to natural light, the remedy
The data obtained suggest that aging is accompanied by a decrease in the involvement of melanopsin (light receptor) in visual perception. However, the retina manages to compensate for this loss by increasing the sensitivity of other photoreceptors. As a result, older people need to be exposed to light richer in wavelengths, that is to say, light whose characteristics are those of sunlight.
“This is the discovery of a new adaptive mechanism of the retina during aging – allowing the elderly subject to remain sensitive to light despite the browning of the lens. These results are also of clinical interest, encouraging people older people to expose themselves more to daylight, richer in wavelengths, rather than to artificial light, in order to avoid developing sleep disorders and other alterations such as speech disorders. “mood or metabolism… Finally, they offer new perspectives for optimally personalizing phototherapies/light therapies intended for the care of older people”explains Claude Gronfier, researcher at Inserm, last author of the study.
