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New Research Shows Blue Light Can “Reset Our Internal Clocks”


A new study into the effects of blue light on retinal cells has linked blue light exposure to a disruption in circadian rhythm, resulting in poor sleep and diminished faculty.

In the study, researchers at San Diego’s Salk Institute demonstrated the effects of blue light on a small cluster of light-sensitive cells in the retina. The retina is a sensory membrane situated at the back of the eye, and is responsible for converting light into neural signals for your brain to process. 

When exposed to blue light, such as that emitted by digital devices, these retinal cells produce a protein known as Melanopsin which suppresses the production of Melatonin – the hormone responsible for regulating sleep. This balance helps control our consciousness, sleep cycles and general alertness throughout the day.

However, researchers have now found that by encouraging Melanopsin production at unnatural times of the day, you are effectively pressing a biological ‘reset button’ on your internal body clock. By disrupting your circadian rhythm and halting Melatonin production, Melanopsin offsets feelings of tiredness in the evenings and degrades the quality of your sleep.

This can lead to fatigue, difficulty focusing, and fluctuations in mood. In fact, in a recent survey of people suffering from depression, most participants reported getting an unadvisedly small amount of sleep day to day.

The danger of artificial blue light

The effect of blue light on your eyes, and subsequently your brain, is more problematic due to our increased reliance of digital devices for work and entertainment. While blue light from the sun is helpful for facilitating daily life, its effect on the brain becomes problematic when we use screens at night – browsing Instagram, responding to emails or watching Netflix. 

blue light circadian rhythm

Professor Sachin Panda, Salk Institute

A high energy visible (HEV) light range, blue light is emitted from the LED screens we use every day, penetrating to the back of our eyes and sending various signals to our brains via the production of proteins and hormones. These signals help us wake up and keep us alert during the day, but at night they keep us in an unnatural state of hyper-alertness.

“We are continuously exposed to artificial light, whether from screen time, spending the day indoors or staying awake late at night,” says Sachin Panda, senior author of the study. “This lifestyle causes disruptions to our circadian rhythms and has deleterious consequences on health.”

For these reasons, over-exposure to blue light has been shown to have an significant impact on our mental and physical wellbeing, and is particularly damaging for children, whose eyes have not fully developed.

Researchers at the Salk Institute hope that a better understanding of Melanopsin and the wider impact of light exposure on our eyes, may lead to new developments in the treatments of migraines, insomnia, jet lag and other sleep-based disorders.

blue light circadian rhythm

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