13 Feb , 18:57
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City life is accompanied by an incessant hum: traffic outside the window, humming air conditioners, vibrations from the metro underfoot. All of this imperceptibly accumulates in the body, undermining the nervous system. But scientists from China have discovered an unexpected ally in the fight against this invisible enemy — ordinary blue light. The results are published in the journal Physiology & Behavior.
A research team from Fudan University, led by Longfei Huo and Muqing Liu, set out to determine whether it's possible to counteract stress from constant vibrations without eliminating the source of irritation itself. For their experiments, they chose zebrafish — tiny striped aquarium inhabitants that have long become indispensable assistants to neurobiologists thanks to the remarkable similarity of their hormonal system to that of humans.
In the first stage, the scientists determined which specific vibration most strongly rattled the nerves of their subjects. Over the course of a week, fish were daily exposed to oscillations of different frequencies — 30, 50, and 100 Hz. The winner in this dubious competition was 100 Hz: at this frequency, the fish stubbornly hugged the bottom and shied away from illuminated areas — classic signs of an anxious state.
Then came the main experiment. Aquariums with vibrating fish were illuminated with light of different hues: red, green, white, and blue. And here the researchers were in for a surprise — it was blue light with a wavelength of 455 nanometers that literally transformed the animals' behavior.
Fish under blue lamps seemed to forget about the unpleasant shaking. They boldly rose to the water's surface, actively explored their space, and willingly socialized with their counterparts. In a special test for social anxiety, they spent considerably more time near other individuals. Red light, however, not only failed to help — in some cases, it even intensified fearfulness.
Blood analysis confirmed the visual observations. Vibration predictably elevated levels of cortisol and noradrenaline — hormones the body releases into the bloodstream under stress. However, blue lighting blocked this release. Moreover, it increased the concentration of serotonin — the very "feel-good hormone."
Scientists believe the secret lies in special cells of the retina containing the light-sensitive protein melanopsin. This pigment is most responsive specifically to the blue part of the spectrum and is directly connected to brain centers controlling emotions and hormone production.
The study authors emphasize: it's too early to draw definitive conclusions applicable to humans — additional research will be needed for that. However, the obtained data opens an enticing prospect: simple lighting adjustments in noisy workshops, offices with humming equipment, or residential buildings near highways could become an accessible way to protect the nervous system — without pills or medical prescriptions.
