Daily blue light shortens lifespan, causes brain neurodegeneration in Drosophila

If you are a human and not a fly here is what concerns you "... humans are exposed to more blue-enriched LED illumination for most of the day, or even at night due to shift work and light pollution in large cities.6 However, long-term consequences of increased daily blue-light exposure across the human lifespan are not known." saved you a clickbait.

I made a (what most people would consider terrible) vim color scheme that has no blue light in it (it's like an old amber terminal). Initially I thought I would hate it and switch back in a couple days/weeks, but I actually find it very nice, and switching to anything w/ blue light or a "normal color scheme" with blues and greens now weirdly feels like an assault. Feel free to give it a whirl: https://github.com/camgunz/amber

All: we've compressed the title in order to make space for the fruit flies. Now it is no longer baity.

This result is interesting in its own right, so hopefully the thread can proceed to talking about other bits than baity titles and insects not being mammals.

Insects aside, I realized there was something wrong about blue light much before any articles appeared about its negative effects on our circadian cycles. It was nearly 20 years back when I bought some of the then young blue and white leds to make some experiments with them, and I quickly realized I hated blue ones. No matter how I reduced the current through them, their light made me feel uncomfortable and didn't like as well cold white ones because they emit more blue light than warm white leds. I still have in a drawer those 10 leds I bought, none of them was ever used in any project. Unfortunately lots of gadgets appeared in the early 2k and they all used blue leds which were going to become the standard pretty much everywhere. It was then when I realized how much and why I disliked that light: it made me nervous; I couldn't stare at a blue led light, especially the bright ones, for some time without feeling anxiety. Then one day I read about how blue light affects us negatively and went "aha!". Now I mask or paint, or even swap where possible, all blue leds those lazy designers keep sticking into gadgets and appliances.

What intensity of light, for how long compared to sunlight?

Every time I hear these blue-light crusaders I am reminded of that “iPads are bad for reading” so-called experiment where the iPads were fixed to the desktop set at maximum brightness with a custom font chosen by the experiment lead. Basically attempting to make life as uncomfortable for the subjects as possible, then blaming all the negative effects on blue light emitted by the iPad.

So short version: is this study meaningful in an way or does it shorten lifespan by using extremely bright blue light for many hours longer than a natural day/night cycle?

edit: they maintained similar photon flux density so the blue light would have been extremely bright to compensate for being a single wavelength.

Edit2: the actually useful words in that linked paper are about two paragraphs, the rest is baseless speculation. An effect was observed, with no mechanism described, therefore extrapolation beyond the experimental conditions is entirely in the realm of fan fiction and soap opera (ie: emotive drama).

So to bring this a little bit back to biology (and away from the fact that the article says little about humans) I would conjecture that the issue with blue light may stem from Rayleigh scattering [1] of sunlight and the subsequent phenomenon whereby the light that reaches us has a lot of the blue component removed.

In the late afternoon, all the blue light get caught and even some of the red, since the sun is now not just an atmosphere-length but an atmosphere length plus a radius of the earth length from the observer and hence has more distance to get scattered. This would mean we get orange-ish light.

Have biologists pointed this out?

[1] https://en.wikipedia.org/wiki/Rayleigh_scattering

This is confusing to me, would love if someone helped elucidate the details. My previous understanding was that bluelight is harmful because bluelight visually interferes with the body's circadian rhythm by leading the body to believe it's still daytime when it may not be.

This article says that "any bluelight is bad", is that incorrect? I don't understand, isn't bluelight measured as light on the 450nm range of the electromagnetic spectrum, whereas visual sunlight ranges from 400-700nm? So, is the thesis that light at 450nm from the sun is only emitted when the sun is highest in the sky, for a few hours a day, whereas bluelight from screens is ever present—causing the circadian rhythm to go out of whack (?).

The article also states that blue light on any part of the body may cause mitochondrial damage. I wonder if the most proactive biohackers would be inclined to wear long-sleeves at non-peak hours to counter this problem. [0]

Maybe this is why Dave Asprey is seen always wearing his blue light blocking glasses, even during daylight hours.

I am also not so inclined to dismiss this data because it only addresses fruit flies. It seems natural to believe that the closer we get to following the circadian cycles we evolved alongside with, the more likely our bodies are to behave optimally. Sure, we may be more resilient to these types of stressors than fruit flies, but, we already know that obeying circadian cycles is a key component to achieving better health, and the work of this paper just seems to push that idea a bit further than we may have originally been lead to believe. It doesn't take much of a stretch of the imagination to guess about how these factors could affect us.

[0] https://www.nature.com/articles/s41467-018-02934-5

Blue Light FUD is an industry now. Although blue light exposure at night is detrimental due to melatonin blocking, during the day, it's important - both blue spectrum light and brightness. The fact that we spend most of the time indoors during the day is one of the reason of the wide incidence of myopia (shortsightness).

I warned LensCrafters that they may expect class action lawsuits as they call blue light "harmful" and offer coating, which reduces blue light both during the day and at night, which could be a trick to make people shortsighted to sell them prescription eyeglasses later.

To all the non-biology people saying essentially "meh, flies," we're not as different from flies as you might think. Model organisms aren't just chosen because they're easy to study. They're chosen because At the genetic, molecular, and cellular level results actually transfer to us. This may not be obvious if you haven't done advanced studies in biology.

*in Drosophila

Their model animal is a fly (Drosophila). I can imagine that impacting the claims significantly. Insects and mammals differ quite a lot.

I wouldn’t expect the same results in mammals (or any animals really).

The report also states that flies living with blue LEDs with yellow filters lived more-or-less as long as the flies grown in darkness.

That's rather comforting to me as most if not all LED fixtures have these.

I only use nightlight (~red tint) on all of my devices at all times and people think I'm crazy. I can't even go back to normal -- it physically hurts and everything just looks super blue.

Wanting to lower the energy of photons that are about to hit your face and get focused into the back of your eye is completely reasonable. The only argument against this practice is that the effects of LED screens is negligible, which is apparently false according to this paper.

On the other hand, a friend of mine who is a bio guy told me some wavelengths of light turn on some wound healing mechanisms in our body.

I think it was 660 or 670 nm (red light)

Is there some demonstrable decrease in longevity for sailors (absent the obvious mortality risks of drowning)? It seems to me that if there was a fundamental problem with humans dealing with long-term exposure to blue light, admittedly reflected rather than directly emitted, it would show up in either sailors or those that live along ocean coastlines.

Of course it's possible that reflected blue light has different effects.

Blue (and any high energy light) is known to facilitate radical formation, redox and other electronic transitions, hence "ionizing radiation". It breaks chemical bonds. Fruit flies are small enough to be translucent to visible light. It is not unreasonable to think that blue photons wreak chemical havoc in the bodies of small bugs, not unlike x-rays in mammals.

Highly recommend blue light blocking glasses. Helped my sleep quality a lot.

Was very surprised by how much light coming in from the city was keeping me awake.

Taking melatonin worked for a while but I feel like it really messes with you.

Surely walking around outside exposes you to plenty of blue light. I think the issue is when people stay up late working at the computer.

Glad I'm not a fly that lives less than 2 months!

e-ink laptop pls

Nice clickbait. Full title of the article:

> Daily blue-light exposure shortens lifespan and causes brain neurodegeneration in Drosophila

Drosophila are fruit flies. File under "interesting, but likely not applicable to mammals".

EDIT: From front page to flagged in 32 minutes. That's impressive.