Prolonged exposure to blue light from your phone, computer and household fixtures may affect your longevity, even if it’s not shining in your eyes.

New research at Oregon State University suggests that the blue wavelengths produced by light-emitting diodes damage cells in the brain as well as retinas.

Jaga Giebultowicz, a researcher in the OSU College of Science who studies biological clocks, led a research collaboration that examined how fruit flies (Drosophila melanogaster) responded to daily 12-hour exposures to blue LED light – similar to the prevalent blue wavelength in devices like phones and tablets – and found that the light accelerated aging.

Flies subjected to daily cycles of 12 hours in light and 12 hours in darkness had shorter lives compared to flies kept in total darkness or those kept in light with the blue wavelengths filtered out. The flies exposed to blue light showed damage to their retinal cells and brain neurons and had impaired locomotion – the flies’ ability to climb the walls of their enclosures, a common behavior, was diminished.

“The fact that the light was accelerating aging in the flies was very surprising to us at first,” said Giebultowicz, a professor of integrative biology. “We’d measured the expression of some genes in old flies, and found that stress-response, protective genes were expressed if flies were kept in the light. We hypothesized that light was regulating those genes. Then we started asking, what is it in the light that is harmful to them, and we looked at the spectrum of light. It was very clear cut that although light without blue slightly shortened their lifespan, just blue light alone shortened their lifespan very dramatically.”

Natural light, Giebultowicz notes, is crucial for the body’s circadian rhythm – the 24-hour cycle of physiological processes such as brain wave activity, hormone production, and cell regeneration.