This post is part of a series of posts to commemorate International Dark Sky Week (19th-26th April 2020), dedicated to celebrating the night sky. Our lighting practices don’t only affect astronomy – they can impact other important things too. I’ll dive into some of these, and a few things you can do to make a difference.
Light pollution can have serious negative impacts on human health. Reducing exposure to artificial lighting at night helps our bodies revert to their natural circadian rhythm, making us healthier and less at risk of major diseases.
The circadian rhythm can be thought of as an internal clock that runs in the background of the human brain. It regulates sleep, eating patterns, the release of hormones, and other important functions. Daylight is the main environmental factor that influences the circadian rhythm, and darkness is an important cue for its absence, and for biological processes like sleep to start taking place.
Exposing ourselves to artificial lighting at nighttime means that the darkness we need for these nighttime processes is not enough, or even fully absent sometimes. This can have catastrophic health consequences. Exposure to light pollution from outside sources as well as electronic devices disrupts the circadian time structure. This leads to an increased the risk of diabetes, cardiovascular disease, obesity and even mood disorders. Nighttime shift work has also been classified as a probable carcinogen.
Fortunately there are ways to protect ourselves. Since blue light is the most harmful type of artificial light, there are apps for phones and laptops that filter it out of electronic devices by making screens more red (f.lux for laptops, Twilight for smartphones and tablets, and the in-built Night Shift settings for iOS devices). Aim to reduce light exposure in the evenings by switching to ‘warmer’, more yellow light bulbs, and turning as many lights off as possible. Since light from outdoors also poses a problem, ensure that outdoor lighting is properly directed downwards.
The effects of light pollution aren’t just external and environmental – they can affect our health too, and it’s important to change our relationship to artificial light to preserve our own health.