Artificial light “can prove to be a formidable polluter”, warns a member of the National Academy of Medicine

On the occasion of the 16th edition of the national operation to raise awareness of light pollution, doctor Jean-Louis Dufier calls for following the natural rhythm of the sun to determine sunrise and sunset times and avoid serious illnesses.

Artificial light “can prove to be a formidable polluter” and cause serious illnesses, such as cancer, particularly in those who have “night work”alert Saturday October 12 on franceinfo Jean-Louis Dufier, ophthalmologist and member of the National Academy of Medicine, co-author of the report “Light pollution and public health”, published by the Academy of Medicine. On the occasion of the 16th edition of the national operation to raise awareness of light pollution this Saturday, the ophthalmologist calls for “live exactly according to the sleep-wake rhythm”. According to him, to live in good health, “you have to stay tuned to the natural rhythm of the sun”.

franceinfo: Why are artificial lights harmful to health?

Jean-Louis Duffer: Unlike other sources of pollution, light is rarely denounced, undoubtedly because it is particularly insidious. However, this beneficial light, which was also deified by the Egyptians, can prove to be a formidable polluter. What are its harms? Fatigue, mood disorders, reduced attention, alertness which can also be a source of road accidents, drowsiness due to lack of sleep, sleep disturbances, etc.

Why do these lights disrupt our body?

All this comes from the fact that, through misuse, our exposure to artificial light day and night ultimately causes our fellow citizens to lack sleep, and not just adults. Light interacts with our retina. It is obviously through the retina that the phenomenon of vision occurs. In retinal cells we have means of capturing light to cause the transformation of light photons into electrons which will go all along the visual pathways to the occipital cortex to produce this phenomenon of vision. Not only does light enable the phenomenon of vision, but it gives the brain information about day and night. So a sleep deficit will lead to dysregulation of the sleep-wake cycle which is so important.

Can this disruption lead to serious illnesses?

In a study of 115,000 American nurses who were followed for ten years, a significant increase of almost 80% in the relative risk of breast cancer was shown when there were at least three nights worked per week for 20 years. Obviously, people who work night shifts are particularly exposed.

What advice do you give to the French to protect themselves from artificial light?

“Nature is a gentle guide”said Ronsard. You have to live exactly according to the sleep-wake rhythm, that is to say 9 hours of sleep. Basically, follow the arrival of night around 8-9 p.m. and wake up around 7 a.m. You have to stay tuned to the natural rhythm of the sun.