Increasing light pollution has a negative impact on our health

For around ten years, the amount of electric lighting at night has been increasing by almost ten percent every year. This has a particular impact on the 4.4 billion people worldwide who live in cities. Excessive exposure to light at night can not only lead to sleep disorders, it also increases the risk of diseases such as obesity, depression, diabetes and cancer. Eva Schernhammer from MedUni Vienna's Center for Public Health and an international team of researchers have reviewed and summarized studies on the harmful effects of light pollution. Their overview has just been published in the top journal "Science".

According to research, too much artificial light in the dark can affect the circadian physiology ("biorhythm") and thus those bodily functions that are clocked by the change between day and night. For example, sleep or the production of hormones are impaired, which can lead to a number of chronic diseases.

In addition, excessive exposure to light at night puts stress on the visual system, which can also have an impact on the whole body. This is because even visual stimuli that go unnoticed by sleepers can trigger processes that disrupt vital recovery and repair mechanisms. The development of cardiovascular diseases and cancer are also associated with exposure to artificial light at night.

For example, there is evidence of an increased risk of cancer in people who regularly work at night. Exposure to light at night also weakens the immune system and is considered a risk factor for type 2 diabetes, high blood pressure, obesity and depression.

Measures needed to reduce light pollution

"The studies on the effects of exposure to light at night paint a worrying picture"

Eva Schernhammer

However, Schernhammer and her colleagues from Poland and the USA identified inconsistent approaches in the research as part of their analysis, leading to partially divergent results.

"In view of the growing problem, we therefore urgently call for further scientific studies that include, for example, considerations on individual exposure to light indoors," says Schernhammer. A clear study situation is necessary in order to be able to formulate reliable recommendations for healthier outdoor lighting at night and to convince political decision-makers to take measures to reduce light pollution.

What is light pollution?

The term light pollution has become established in the scientific community to describe the sum of all the detrimental effects of excessive exposure to light at night on the environment and people. Researchers see night-time lighting bans, such as those introduced in some cities as a result of the energy crisis, as a step in the right direction.

However, measures can also be taken within your own four walls to protect your health: Amber-colored, warm white light sources instead of light sources with a high blue content at night, for example, can already make a contribution to prevention.

Related articles:

https://news.pro.earth/2023/04/19/lichtverschmutzung-die-helle-not-nachtaktiver-insekten/

Publication: Science
Reducing nighttime light exposure in the urban environment to benefit human health and society;
K. M. Zielinska-Dabkowska1, E. S. Schernhammer, J. P. Hanifin, G. C. Brainard
doi: 10.1126/science.adg3173