[Creative Cultivation Program] Does playing with your phone hurt your brain? What the fruit fly experiment tells us

Presumably, for many people, checking their phones first thing after waking up has become a "sign" to start the day. Throughout the day afterwards, phones have conquered men, women, young and old with their "unexpected magic" - office workers frequently check their phones, which helps them keep abreast of their bosses' "latest developments"; students love to browse Weibo, and the masses must eat the "freshest melons" of the day; even many middle-aged and elderly people who previously disdained electronic products have begun to live a life of "never leaving their phones, always having news"... Mobile phones have undoubtedly become a necessity in the lives of contemporary people.

But do you know that when you are happily looking at your phone, you are accompanied by the "omnipresent" blue light. Blue light is a component of natural light, with high energy and strong penetrating power. Long-term exposure to this high-energy light will undoubtedly cause damage to the body.

So, how big is this harm? Is it "alarmist" or "really harmful"?

In 2019, the research team of Oregon State University (Jaga Giebultowicz) gave a detailed answer to the "lethality" of blue light, and the related work was published in the Nature journal "Aging". In this experiment, they used a blue LED light, which is similar to the blue light emitted by devices such as mobile phones and tablets. They used this light to expose fruit flies to blue light for 12 hours a day to observe possible adverse reactions. Surprisingly, they found that fruit flies exposed to blue light for 12 hours a day not only suffered damage to the retina and brain neurons, but also had obvious impaired motor ability, making it difficult for them to crawl on the walls of the fence.

Moreover, long-term exposure to blue light disrupts the sleep and circadian rhythm of fruit flies, and stress protection genes in the body are highly expressed under light conditions, greatly shortening the lifespan of fruit flies and accelerating their aging. Moreover, the above blue light damage will not be "absolved" just because fruit flies have impaired vision and cannot sense light.

Unexpectedly, the small electronic screen is so lethal that the researchers could not help but take a deep breath. So, what factors affect this blue light damage? To clarify this issue, the researchers conducted a more in-depth study. Hard work pays off. Three years later in 2022, they announced again in the Nature journal Aging: Blue light hazards are age-dependent, that is, with the increase of age, its destructive effects on organisms will further worsen.

In this study, fruit fly larvae were first placed in a dark environment for a period of time, namely 2 days; 20 days; 40 days; and 60 days, and then transferred to a constant blue light environment created by LED lights to be observed by researchers.

Consistent with the conclusions of the 2019 study, changes in the lighting environment shortened the lifespan of fruit flies overall. Compared with the 2019 study in which all fruit flies lost half their lifespan under light, the "lifespan reduction" phenomenon was more prominent in the group of old fruit flies cultured in darkness for 60 days. According to statistics, the survival time of young fruit flies under blue light irradiation is 2-3 times that of old fruit flies; in addition, tests on brain nerves found that brain nerve degeneration in old fruit flies was more serious after exposure to blue light.

It seems that fruit flies become more susceptible to blue light as they age. But what causes this? Scientists are puzzled. To find the culprit, researchers conducted further molecular experiments.

They found that it was related to the energy supply of the cell. As we all know, in our cells, mitochondria are known as "power plants" that can produce ATP as energy for the body. However, when mitochondria are depleted and their vitality decreases, the energy available to the cell becomes less and less, and the cell no longer "grows vigorously", thus accelerating aging - this seems to be the key point of "shortening the lifespan" of fruit flies - the researchers tested the mitochondrial activity of old fruit flies under blue light and non-blue light, and found that the mitochondrial content and mitochondrial respiratory chain function were depleted by age and light, respectively.

Therefore, from the fruit fly experiment, blue light accelerates aging and affects the nervous system. Although these experiments have not been repeated on humans, in recent years, there have been more and more studies on the effects of blue light on human physiology, and the effects of blue light from mobile phones and various computer screens on humans have also received more attention.