13 Feb , 16:15
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Constant noise and vibration from transportation and industrial equipment can gradually increase levels of stress and anxiety. A new study has shown that exposure to blue light can mitigate these negative effects even when physical irritation continues.
As reported by TUT.AZ with reference to the journal Physiology & Behavior, these conclusions were drawn from a laboratory experiment.
The work was conducted by specialists led by Longfei Ho and Muqin Liu from Fudan University. As an experimental model, the scientists chose zebrafish — a common subject of neurobiological research, since their hormonal system is largely comparable to that of humans.
In the first stage of the experiment, researchers determined which vibration frequencies provoked the most pronounced anxiety response. Over the course of a week, fish were subjected daily to oscillations at frequencies of 30, 50, and 100 Hz. The strongest stress was caused by 100 Hz vibration: the specimens more frequently stayed at the bottom of the aquarium and avoided illuminated areas, which is considered a typical sign of anxious behavior.
Light therapy was then added to the exposure. During vibration, the aquariums were illuminated with red (654 nm), green (512 nm), white, and blue light (455 nm). The blue spectrum demonstrated the most noticeable positive effect — under it, signs of anxiety decreased significantly.
Under blue lighting, fish more actively explored the upper layers of water and exhibited more natural social interaction. In additional testing, they were more frequently found near other specimens, indicating a reduction in social anxiety. Red light, on the contrary, in some cases increased avoidance behavior.
Biochemical analysis confirmed the behavioral observations. Vibration contributed to increased levels of cortisol and noradrenaline — stress hormones. Under blue light exposure, these levels decreased, while the concentration of serotonin, associated with positive emotional state, increased.
The study authors attribute the discovered effect to the activation of light-sensitive retinal cells containing melanopsin. This pigment is particularly sensitive to the blue spectrum and is involved in transmitting signals to brain regions responsible for regulating emotions and hormonal balance.
The scientists emphasize that the experiment was conducted on animals, therefore additional research is needed to confirm a similar effect in humans. Nevertheless, the obtained data indicate the potential of light therapy as an accessible and non-invasive method for reducing anxiety caused by adverse environmental factors.
According to the researchers, optimization of lighting in industrial premises and offices with high noise levels could become a supplementary measure for preventing stress disorders, especially in early stages when medication intervention is not yet required.
