Mobile phone blue light not only harms the eyes but may also increase the risk of depression

Someone has done this kind of statistics: staring at the phone for five or six hours a day is equivalent to exposing our eyes to all the blue light radiated by the sun in a lifetime, in a few years. And the consequences are serious: excessive blue light radiation can cause myopia; it may also cause blurred vision and visual fatigue; it can stimulate brown pigments to produce freckles on the skin; it may even cause blindness.

The harm of blue light to the human body has been repeatedly mentioned, and it is right to advise young people to play less with mobile phones and other electronic products. It is worth noting that recent studies have shown that blue light is not only harmful to the human body, but also affects people's emotions, and blue light may increase the chance of depression.

Recently, a study published in the American journal Sleep by researchers from Chongshin Women's University in South Korea showed that looking at mobile phones before going to bed delays sleep time, affects mental health, and makes people more likely to suffer from depression and anxiety. The "culprit" is most likely the light emitted by mobile phones in the dark.

The study surveyed 160 people aged between 20 and 30, and found that they spent five times more time playing with their phones before going to bed than the average person. The results showed that long-term use of mobile phones before going to bed can have a negative impact on health and psychology, increasing the chances of depression by 20% and anxiety by 14%, while delaying bedtime can increase the chances of insomnia by 41%.

Previously, some people believed that rhythm or sleep disorders could lead to an increased risk of depression, and it is very likely that the culprit is the blue light from mobile phones.

According to a research result of Professor Xue Tian from the University of Science and Technology of China and Zhao Huan's team from Hefei University, it is the abnormal light at night that causes depressive-like behavior. The increase in blue light at night will affect specific neural circuits in the brain, leading to the appearance of depressive symptoms.

They conducted an experiment on mice: they selected two hours between 21:00 and 23:00 every night during the mice's circadian rhythm and exposed them to blue light for three consecutive weeks.

The results showed that the mice's circadian rhythms were not changed, but some unusual behaviors gradually emerged: when forced to swim, they showed a state of abandonment and their preference for sugar water decreased. Since these behaviors have certain similarities with human depressive behaviors, the researchers defined them as depressive-like behaviors.

Not only that, after the blue light exposure was cancelled every night, the mice did not recover immediately, and the depressive-like behavior continued for up to 3 weeks.

This study provides neuroscientific evidence based on model animal research, making "blue light" a major suspect in causing depression; at the same time, it explains for the first time the underlying mechanism of the completely opposite emotional effects of light during the day and at night.

However, the authors said in the conclusion of the paper that to understand the effects of increased light at night on mood, finding out the neural pathways that night light affects the brain is the first step. If light activates the same neural circuits in humans, these results may help explain how excessive night light affects humans and why it is associated with depressive symptoms.

Of course, this study does not mean that "playing with mobile phones before going to bed will cause depression". There are many reasons for depression, and they are not the only ones that work. The purpose of the study is nothing more than to tell people that excessive use of mobile phones can affect people's physical health and mood.

Nowadays, mobile phones, tablets, and computers have already filled our lives. In addition to working with various electronic products during the day, lights, mobile phones, and televisions also occupy our eyes at night. In an environment where "blue light" is everywhere, staying away from blue light radiation is beneficial to physical health and mental emotions.