Light Exposure in Evening, Night

Light exposure in the evening and night is a significant issue in our culture.

Over the past decades, home environments have generally come to have more lighting – so now when you go into the kitchen or the bathroom in the late evening and switch on the light, often what comes on is a bank of lights and a lot of lumens.

For many of us, the evening is filled with “screen time”. Not a TV screen 8 feet away – today it is often a computer monitor, laptop or tablet screen and these may be quite close to the eyes. Even light from the screen of a smart phone held close to the face can be significant.

The light from electronic screens is generally quite high in blue light. Blue light is particularly activating regarding circadian rhythms and the suppression of melatonin synthesis.

A lesser-known aspect to being exposed to a lot of electronic screen light is that this is polarized light. It is a little-noted fact that humans do perceive polarization of light. Sunlight is polarized, so one could think that polarized light might trigger a circadian response in people.

The problem of light exposure in the evening and night has caused concern and been the subject of research and media articles.

What can be done?

  • learn more and be aware that this is an active area of research, so more info should come available over the coming years
  • be aware of “light hygiene” in the evening and night. Consider taking some steps to reduce your light exposure at these times.
  • look into programs or apps for your electronics that can be set to dim the emitted light and/or alter the tone of the light to lessen the proportion of blue in it. I’m sure the number of apps available will grow rapidly and I’m not going to try to be aware of all the apps and which is the best one. Myself, I use an app on my laptop called “f.lux”, which is widely used (since new apps become available all the time, I’m not claiming that this is the best.). For the Android market, I have seen recommendation for Bluelight Filter (Android).
  • Consider using “blue-blocker” glasses in the evening/night to reduce your exposure to high levels of blue light. These are widely available and not expensive. They look like sunglasses, except that the lenses are amber/orange.

A good over-view of the topic can be found on the “Calories Proper” blog, which is also an interesting blog in many ways. This is the blog of the widely-respected circadian enthusiast Bill Lagakos.  LINK

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