Michael from f.lux: This research is from a very talented group of researchers, but it is unclear if it will translate from nocturnal mice to humans (as others have said). The evidence in humans is mixed, but it either shows no effect or a tendency in the other direction. There is a study in the same issue (Spitschan) that says there is no effect in humans.
1. First, the study does not question the contribution of melanopsin (the blue-cyan opsin that got everyone talking about "blue light") - it asks a more subtle question: when you hold melanopsin stimulation constant, what does the remaining light do and why? Here they are finding whether the cones oppose or boost melanopsin based on color signals. But regardless of how this works in humans, we should still expect bright-enough blue light at night to be stimulating, because of the response due to melanopsin.
2. Holding the melanopic portion of a light constant is not something we usually do. For most lights we have today, the "blue" lights would be considerably dimmer than the "yellow/red" ones if we did this. When we compare lights of equal visible brightness, the yellow ones are known to have less effect on human melatonin suppression [Chellappa 2011].
3. The evidence in humans is mixed, but it actually goes the other direction (saying blue is more stimulating), or there is no clear effect. In the same issue, a study on humans by Spitschan found a negative result on whether or not S-cone contrast has an effect: https://www.cell.com/current-biology/fulltext/S0960-9822(19)...
3b. Other research (in monochromatic and polychromatic light) finds that humans are more sensitive to blue light than melanopsin would suggest. See a list below.
4. We're all still trying to explain how the transition to dusk is blue/purple, while our own lighting doesn't do that. We have built our lighting to be relatively bright, but warm. It is not "natural" to extend the day like we do, but it likely would not help anything to make the lights more blue, unless they were quite a lot dimmer, or used very novel spectra.
Here is a list of references for the evidence +/- blue sensitivity (not melanopsin) in humans:
2. The Spitschan study from this same issue of Current Biology says there is no effect in either direction when comparing 83x S-cone contrast. The lights here are "pink" (which has a lot of blue) and "orange" which has very little. https://www.cell.com/current-biology/fulltext/S0960-9822(19)...
4. There is one important study in humans (Gooley 2010) that says we can be more sensitive to 555nm light after two days in dim light, so that mirrors this study. But this is not exactly comparable to the study cited here due to sensitization: it stands on its own due to the duration of the experiment.
It would be interesting if we could find some "truth" to the idea that twilight colors affect human circadian entrainment - it has been a recurrent idea for many years. We finally have the technology to target melanopsin separately from the S-cone (see Spitschan's work for an example).
For the press these results get, you'd be surprised that there has been extremely little research funding for most of these things in the last ten years. In a way, I hope that mixed results like these might help! How light affects us at lower levels, and how different we are from each other is not "solved" at all, so there is still a lot of work to do.
It's quite nice seeing someone who has a entrenched interest promoting awareness of new evidence, that—whilst it may hurt their own stake—is important to furthering humanity's understanding and getting to the ground level of what the truth actually is.
We just so obviously need more behavior like this. It's taboo in our culture to change a stance you once publicly made and there are so many things wrong with that. To not change your mind is to not be in dialog with the world and all the new evidence that's accumulating there within.
Personal guess is that blue light probably isn't conducive to staying circadian-aligned, but like the parent am open to new evidence.
Regardless of the actual effect on sleep, the "night light" modes for screens very much reduces the eye strain I feel. So much so that I've enabled some version of it on every screen I use, permanently, not only at night.
I find it much more pleasant and comfortable. Interestingly, I've gotten so use to it my brain compensates for the color change and it looks pretty normal to me.
Our eyes have absolutely incredible colour correction, running all the time and so well that we just don’t notice it; except for some edge cases where it gets tricked (eg the whole dress saga, or optical illusions you can find).
I am always reminded of it when accidentally I go fullscreen mode and my flux turns off. It really hits you how bright the screen gets (and I am not using full filter, I like to keep colour distortion at bay).
Even if the blue light is a myth I will keep on using flux.
I agree. Even if blue light wouldn't interfere with sleep in any way, the glow of the screen in the evening feels so straining to eyes that just for this reason I like to use f.lux.
I have f.lux running on my desktop and laptops, and the way it helps me "come down" in an evening is amazing. I don't know why I never thought to donate before, but your comment made me think of it, and I'm going to give a donation right now!
Thanks for the awesome software, but I have to ask why it keeps asking me for my location every time I boot up my system. I use a custom setting that’s constant throughout the day. Just thought I’d give it a shot and maybe someone from flux will take notice
I have life long (since puberty) chronic insomnia and regular debilitating migraines (every couple weeks), both of which require a variety of ongoing medications, and I can honestly say removing blue light as much as possible and reducing brightness to the minimum that’s still practical, on every electronic device I own, has transformed my life.
I used to get headaches using my computer or phone unless it was in daylight, and couldn’t use any screen late at night, but these days it’s no problem at all. If I’m in a hotel or somewhere where I can’t change the brightness/colours then I get more headaches again.
It absolutely hasn’t cured me, and I still have both issues, but there has been a noticeable increase in quality of life and ability to use screens at night.
Our screens are way too bright because it looks good for marketing purposes. You get used to very low screen brightnesses very quickly, even on your TV, and whether it’s blue light or just brightness in general, I definitely think all these bright lights shined into our eyeballs at close range are doing damage.
I used to have migraines. Then I learned how to relax the muscles in my neck (with meditation). Now I can cure my migraines in about 5 mins. I told my doctor about it. She said yep, nowadays they treat migraines with botox injected into the tensed muscles. Like much of medicine, it treats the symptom rather than the cause. I believe that the root cause of most migraines is emotional tension.
I wish you peace and freedom from anxiety. The bright lights don't cause your migraines. You think they do, so you start to stress out. Then your body's automatic response to stress causes the migraines. Multiple-chemical-sensitivity is the same. I had that, too and cured myself with knowledge and stress reduction techniques. This knowledge is the cure.
I prefer bright screens with the full light spectrum. They are easier to read with less eye strain. They don't cause me headaches and I sleep just fine regardless of how late I use them.
This could be placebo. Anything related to sleep or headaches there could be a psychological factor ie because you “know” blue light is bad it becomes a self fulfilling prophecy.
I used flux for a long time and thought it was only relevant for sleep. I found myself using it more during the day as it hurt my eyes less and as a result I also got migraines and headaches less often. Could be a total coincidence or even still placebo, just sharing my anecdote.
I agree there's likely a lot of placebo effect going on around this topic. I think there are certain people who are more photo-sensitive and chroma-sensitive than others, however, I suspect it's not a huge percentage of the population. There are also some potentially huge confounding factors making it harder to tease out the practical effect in our everyday lives. As a first-order effect, there's artificial room lighting itself without blue or screen light that's de-blueified. It seems likely that non-blue artificial light is going to have more effect above baseline than the delta between blue artificial light and 'corrected' non-blue artificial light.
The even bigger effect I wonder about is that the screens we look at generally have content and we look at them because that content is engaging our minds and holding our interest. It's often interactive and involves two-way communication. All of those things are going to be highly stimulating to our brains and I think that will likely swamp the effect of removing blue from the artificial light. We already know that reading or watching exciting content is going to make it harder to fall asleep for some time afterward - regardless if it's on a printed page, live or via a screen. Personally, I find that factor to be much larger than any chroma-effect.
Is it possible or ethical to offer a research option to f.lux? Like you would let the user pick that option and have the software dim the luminosity with or without cutting more specifically blue light then have them report and if they felt any difference after a week/month or a month, repeating the process for a few months/week while either alternating or changing the mode.
Maybe it is a dumb idea as it is too easy to tell whether the software is in full effect or not.
Trouble with f.lux is it reduces blue. Doesnt eliminate it. Speciality glasses give more dramatic results.
Axon or Thermaspecs brand name.
I’m hyper sensitive to lights and medications, 10 minutes of exposure is enough to trigger a migraine. Plus side, it makes trial and error testing Much easier.
similarly, after switching my tv,gaming rig,work laptop,phone to twilight/flux/redshift/night mode for several months, I find going without at night to be uncomfortable almost to the point of pain.
my ex-wife found them to be too dark and painful to her eyes.
Try if you can trigger a migrane if you stay 2-3 hours later than normal on lcd screen, but do neck excercises every 15 minutes of that time.
I thought I had hunger headaches but after some epiphany it turned out that I was not eating for many hours when I was at my computer and when I was at my computer my neck suffered (painlessly) from lack of movement and that (not the hunger) triggered headaches.
I'm doing 24h fasting with no ill effects. Also when headache is building up when I'm at my computer I can make it go away with some neck excercises instead of suffering for hours.
I've been using f.lux (and now the default Night Shift in macOS/iOS) for years. I don't remember if my eyes hurt normally, but I can say that if I now turn it off at night my eyes hurt, I strain and get a headache after a while. It may just be because I'm used to the colours now.
I don't think it has helped my sleep patterns much, though, it's only reduced eye straight for me. Using a computer (or a phone) beyond a certain time usually kills my sleep regardless.
I think everytime you mess with your sleep pattern you may get some headache (oversleeping especially). Also blue light helps to mess your sleep (getting asleep later). Anyway that's how it works with me.
I practically stopped having headaches once I started using blue light blocking glasses. Not only at night, but when I first wake up too, specially if it's still dark.
is this a normal screen late at night in a dark room or a normal screen late in a well-lit room? Because the combination that provokes headaches and eyestrain for me is a bright monitor in a dark room.
I only turn on night mode when the brightness on my Pixel is already at its minimum. It would be nice if I could turn the backlight even lower instead. In complete darkness, even the dimmest setting is unnecessarily bright.
It seems like the ability to further reduce all light (including blue) would be a clear improvement, but I assume there's a reason why the minimum is what it is. Is there some sort of hardware limitation on the minimum brightness of the backlight?
This is a study on mice, which from my minimal research appear to be more wakeful at night. I wouldn't consider this study useful at all in determining how blue light affects humans' sleep.
The original study on blue lights was on a small number of humans, and the delta in sleep was less than 20 mins per night. So if this isn't a useful study, I would hardly consider the original blue light study useful or conclusive either. The only reason why you heard about the original study was because it made the headlines.
It isn't meant to be conclusive. These kinds of studies usually are for indicating whether a certain idea is worth pursuing. It takes more money and time to do conclusive studies on humans with larger sample sizes.
I wouldn't be immediately dismissive just because it was on mice. It shouldn't be used to definitively argue either way.
Tangentially related: I've been experimenting with very bright lights from when I wake up to sunset. In my bedroom/home office I have a couple 6000k LED lights at 8100 lumens making the room almost as bright as noon outdoors. Post-sunset I use dim red lights. I was inspired by SAD lights but didn't like any of the ones I tried so went with high-powered "corn" LED lights in normal fixtures.
I've noticed that I tend to get sleepier at night which is great as before I would have to force myself to go to sleep (I'm a natural night person.)
I've also noticed a small increase in my distance visual acuity (subjectively measured by me using an eye chart so not the most accurate.) I have read that intense outdoor light protects against myopia (see https://www.ncbi.nlm.nih.gov/books/NBK470669/) so I suspect this is related.
I wonder why there's only engineering and so little science in the design of modern dwellings! A lot of our constraints, such as maximum illumination lux have gone away thanks to new technology, but the "wellness science" hasn't been applied. It's not even an established scientific discipline, which is why I'm struggling to come up with a name for it.
I haven't heard of any large construction company or architect firm focusing on human-centric attributes such as:
* Minimising the levels of O3, CO2 and CO
* Fine particulate filtering
* Daylight-equivalent illumination
* Red-shifting illumation to simulate dusk
* Noise insulation such as double-glazed glass or weighted foam partitioning walls
* Etc...
In principle, living and working indoors could be much better for us, but nobody seems to be spending real effort in achieving this.
Instead, everyone is dead set on optimising for square-footage or workers-per-floor, completely disregarding basic humans needs.
For example, the office of a large government agency where I'm contracting has atrocious air-conditioning in their main city office building. The temperatures are over 26C (79F) most of the time, and I get blinding headaches from the CO2 buildup after a day of bad ventilation. After about 2pm I'm basically a zombie and can't concentrate. Noone has bothered to do anything about this for literally years.
(This is not my imagination: Their own staff work in air quality monitoring, so for laughs they used one of their probes in the middle of our floor and it basically read "off scale high" on nearly every metric.)
Meanwhile, another building around the corner has floor-to-ceiling glass windows letting in a lot of light and nice cool refreshing air-conditioning. There, I can work until 6:30pm regularly without feeling run down.
Much of this is covered by The International WELL Building Institute guidelines, latest version is at https://www.wellcertified.com/certification/v2/
but it is only slowly coming in as best practice and is a long way from being compulsory. It doesn't completely cover all the aspects you listed, in particular - relevant to this thread - it doesn't actually require red-shifting to simulate dusk - see FAQ #82 on https://v2.wellcertified.com/v/en/light/feature/3
So although you might consider it inadequate, there are certainly people looking into this and there is lots of science behind it.
I love the LED lights available today. I am able to pack 10x more light per watt into my office using hacked together fixtures to the point it is eye piercingly bright. It really helps in the low light of winter. Before this point, the other efficient option were HID lights but the spectrums on those are all wrong for reasonable residential lighting.
I absolutely agree. As an aside I also have a CO2 monitor (Awair device) and make sure to keep my bedroom/home office below 700ppm. This is easily achieved by keeping the window open. Self experimentation has shown that I tend to yawn quite a bit more at levels greater than 1000ppm.
Did you see this link, posted here a month ago? Opens a whole new world where 30,000 lumens per room is a reasonable option. https://www.benkuhn.net/lux
I didn't see this, thanks for posting it! My thought process was really similar to the author's actually and I've been happy with the results so far. I've distributed the lights around my room with shades to mitigate the unpleasantness factor as opposed to going with the "megabulb".
I made a lamp that does 25k lumens (and about 20k lux at 1 meter) but when I use it to light my room from the ceiling the light is bright enough to be unpleasent. Like going out during sunny day.
Here in the Netherlands the use of green light (540nm) is becomming popular for night lights. It doesn't disrupt sleep patterns of humans, animals and plants and your eyes can see quite well using less brighter lights (saves energy). And green LEDs are relatively cheap.
In studies both green and blue light showed to be the least disruptive (but green is better for night sight). I thought this was strange since it was always believed that blue light is bad.
But it appears this article agrees.
Edit: a lot of plants and corals are grown under red light. So maybe red could be more harmful for your sleep if it triggers growth.
Plants need both blue and red light to grow. Also, plants and animals are so fundamentally different biologically that very few things which affect one have any direct reason to have similar effects on the other.
You don't have to watch them. Just the blinking of TV will distract your brain from racing. That's how I do it. In my case, I rewatch something that I already know by heart - Seinfeld, futurama, etc. If I know the plot, I don't get into it enough to be awake.
I'm on the opposite side of the coin. My brain recognizes any conversation on a left-on TV and "turns on." If I was asleep, I'm about to not be. It is especially bad when I know the episode or movie as I start to pre-quote lines in my head and, shit, now I'm awake.
A drama with a complicated enough plot but generally quiet ie mostly talking no action does it for me. But I need to be sleepy in the first place, such that I could probably just go to bed without tv and also sleep!
Similar experience here... I am able to look at a computer or phone screen right up until I go to sleep. The time at which I get sleepy, and ready for bed, has to do more with my overall daily routine. I practice patterns of making myself go to bed at the same time. The screen time does not seem to make me stay awake. Also, if I am not sleepy when it is 'bed time', exercise after work is a sure fire way to get to sleep earlier.
A few weeks ago I was advised by a lighting specialist that there’s a lot of ongoing disagreement regarding the best approach for reducing how light affects sleep. I was aware that there has been limited research and many of the solutions to this point have been basically “copy flux”.
Thanks for posting this. Very interesting read and has made me change my buying behaviour.
Is there disagreement also regarding the lighting level? I have dimmable lights and I like how I feel when I gradually dim them to darkness before going to sleep.
I don't know; I was particularly looking at color shifting devices and the recommendation was to hold off on the purchase for a few years until the science had a change to settle.
Readit News
1. First, the study does not question the contribution of melanopsin (the blue-cyan opsin that got everyone talking about "blue light") - it asks a more subtle question: when you hold melanopsin stimulation constant, what does the remaining light do and why? Here they are finding whether the cones oppose or boost melanopsin based on color signals. But regardless of how this works in humans, we should still expect bright-enough blue light at night to be stimulating, because of the response due to melanopsin.
2. Holding the melanopic portion of a light constant is not something we usually do. For most lights we have today, the "blue" lights would be considerably dimmer than the "yellow/red" ones if we did this. When we compare lights of equal visible brightness, the yellow ones are known to have less effect on human melatonin suppression [Chellappa 2011].
3. The evidence in humans is mixed, but it actually goes the other direction (saying blue is more stimulating), or there is no clear effect. In the same issue, a study on humans by Spitschan found a negative result on whether or not S-cone contrast has an effect: https://www.cell.com/current-biology/fulltext/S0960-9822(19)...
3b. Other research (in monochromatic and polychromatic light) finds that humans are more sensitive to blue light than melanopsin would suggest. See a list below.
4. We're all still trying to explain how the transition to dusk is blue/purple, while our own lighting doesn't do that. We have built our lighting to be relatively bright, but warm. It is not "natural" to extend the day like we do, but it likely would not help anything to make the lights more blue, unless they were quite a lot dimmer, or used very novel spectra.
Here is a list of references for the evidence +/- blue sensitivity (not melanopsin) in humans:
1. The Thapan study from 2001 indicates extra blue-light sensitivity in addition to melanopsin. Lights are seen for a half hour at night. https://doi.org/10.1111/j.1469-7793.2001.t01-1-00261.x
2. The Spitschan study from this same issue of Current Biology says there is no effect in either direction when comparing 83x S-cone contrast. The lights here are "pink" (which has a lot of blue) and "orange" which has very little. https://www.cell.com/current-biology/fulltext/S0960-9822(19)...
3. The Brainard 2015 study compares 4000k to 17000k lights: at the same "melanopic" level the 17000k lights do a lot more melatonin suppression: https://jdc.jefferson.edu/cgi/viewcontent.cgi?article=1081&c...
4. There is one important study in humans (Gooley 2010) that says we can be more sensitive to 555nm light after two days in dim light, so that mirrors this study. But this is not exactly comparable to the study cited here due to sensitization: it stands on its own due to the duration of the experiment.
It would be interesting if we could find some "truth" to the idea that twilight colors affect human circadian entrainment - it has been a recurrent idea for many years. We finally have the technology to target melanopsin separately from the S-cone (see Spitschan's work for an example).
For the press these results get, you'd be surprised that there has been extremely little research funding for most of these things in the last ten years. In a way, I hope that mixed results like these might help! How light affects us at lower levels, and how different we are from each other is not "solved" at all, so there is still a lot of work to do.
We just so obviously need more behavior like this. It's taboo in our culture to change a stance you once publicly made and there are so many things wrong with that. To not change your mind is to not be in dialog with the world and all the new evidence that's accumulating there within.
Personal guess is that blue light probably isn't conducive to staying circadian-aligned, but like the parent am open to new evidence.
I find it much more pleasant and comfortable. Interestingly, I've gotten so use to it my brain compensates for the color change and it looks pretty normal to me.
Screens totally should be orange by default.
Even if the blue light is a myth I will keep on using flux.
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We deliberately round to the nearest 0.1 degree for privacy (>5 mile box), but typing in a nearby city or airport code is usually fine.
I use specialty glasses that are amazing for for filtering out blue light. Not just your typical prescription glasses that have a minor filter.
I use Fl-41 lenses with wrap arounds (keep out ambient light)
If I Walk into a store without them I have a full blown migraine in 15 minutes. Longer I stay, that worse it is.
With proper glasses I can manage better than an hour before any issues.
So yea, blue lights definitely affect the brain.
Go onto migraine forums and you’ll see a lot of the same reports.
With flux/redshift on, that doesn't happen. Blue light may not be keeping me up, but it definitely fucks my brain up in some complicated way.
I used to get headaches using my computer or phone unless it was in daylight, and couldn’t use any screen late at night, but these days it’s no problem at all. If I’m in a hotel or somewhere where I can’t change the brightness/colours then I get more headaches again.
It absolutely hasn’t cured me, and I still have both issues, but there has been a noticeable increase in quality of life and ability to use screens at night.
Our screens are way too bright because it looks good for marketing purposes. You get used to very low screen brightnesses very quickly, even on your TV, and whether it’s blue light or just brightness in general, I definitely think all these bright lights shined into our eyeballs at close range are doing damage.
I wish you peace and freedom from anxiety. The bright lights don't cause your migraines. You think they do, so you start to stress out. Then your body's automatic response to stress causes the migraines. Multiple-chemical-sensitivity is the same. I had that, too and cured myself with knowledge and stress reduction techniques. This knowledge is the cure.
I agree there's likely a lot of placebo effect going on around this topic. I think there are certain people who are more photo-sensitive and chroma-sensitive than others, however, I suspect it's not a huge percentage of the population. There are also some potentially huge confounding factors making it harder to tease out the practical effect in our everyday lives. As a first-order effect, there's artificial room lighting itself without blue or screen light that's de-blueified. It seems likely that non-blue artificial light is going to have more effect above baseline than the delta between blue artificial light and 'corrected' non-blue artificial light.
The even bigger effect I wonder about is that the screens we look at generally have content and we look at them because that content is engaging our minds and holding our interest. It's often interactive and involves two-way communication. All of those things are going to be highly stimulating to our brains and I think that will likely swamp the effect of removing blue from the artificial light. We already know that reading or watching exciting content is going to make it harder to fall asleep for some time afterward - regardless if it's on a printed page, live or via a screen. Personally, I find that factor to be much larger than any chroma-effect.
Maybe it is a dumb idea as it is too easy to tell whether the software is in full effect or not.
I’m hyper sensitive to lights and medications, 10 minutes of exposure is enough to trigger a migraine. Plus side, it makes trial and error testing Much easier.
my ex-wife found them to be too dark and painful to her eyes.
I thought I had hunger headaches but after some epiphany it turned out that I was not eating for many hours when I was at my computer and when I was at my computer my neck suffered (painlessly) from lack of movement and that (not the hunger) triggered headaches.
I'm doing 24h fasting with no ill effects. Also when headache is building up when I'm at my computer I can make it go away with some neck excercises instead of suffering for hours.
I've been using f.lux (and now the default Night Shift in macOS/iOS) for years. I don't remember if my eyes hurt normally, but I can say that if I now turn it off at night my eyes hurt, I strain and get a headache after a while. It may just be because I'm used to the colours now.
I don't think it has helped my sleep patterns much, though, it's only reduced eye straight for me. Using a computer (or a phone) beyond a certain time usually kills my sleep regardless.
Deleted Comment
After I started using it, I sleep like a baby even when I use Mobile/Laptop just before sleeping.
This software has changed my life.
It seems like the ability to further reduce all light (including blue) would be a clear improvement, but I assume there's a reason why the minimum is what it is. Is there some sort of hardware limitation on the minimum brightness of the backlight?
I wouldn't be immediately dismissive just because it was on mice. It shouldn't be used to definitively argue either way.
I've noticed that I tend to get sleepier at night which is great as before I would have to force myself to go to sleep (I'm a natural night person.)
I've also noticed a small increase in my distance visual acuity (subjectively measured by me using an eye chart so not the most accurate.) I have read that intense outdoor light protects against myopia (see https://www.ncbi.nlm.nih.gov/books/NBK470669/) so I suspect this is related.
I haven't heard of any large construction company or architect firm focusing on human-centric attributes such as:
* Minimising the levels of O3, CO2 and CO
* Fine particulate filtering
* Daylight-equivalent illumination
* Red-shifting illumation to simulate dusk
* Noise insulation such as double-glazed glass or weighted foam partitioning walls
* Etc...
In principle, living and working indoors could be much better for us, but nobody seems to be spending real effort in achieving this.
Instead, everyone is dead set on optimising for square-footage or workers-per-floor, completely disregarding basic humans needs.
For example, the office of a large government agency where I'm contracting has atrocious air-conditioning in their main city office building. The temperatures are over 26C (79F) most of the time, and I get blinding headaches from the CO2 buildup after a day of bad ventilation. After about 2pm I'm basically a zombie and can't concentrate. Noone has bothered to do anything about this for literally years.
(This is not my imagination: Their own staff work in air quality monitoring, so for laughs they used one of their probes in the middle of our floor and it basically read "off scale high" on nearly every metric.)
Meanwhile, another building around the corner has floor-to-ceiling glass windows letting in a lot of light and nice cool refreshing air-conditioning. There, I can work until 6:30pm regularly without feeling run down.
So although you might consider it inadequate, there are certainly people looking into this and there is lots of science behind it.
I'll experiment with spreading lights a bit more.
In studies both green and blue light showed to be the least disruptive (but green is better for night sight). I thought this was strange since it was always believed that blue light is bad.
But it appears this article agrees.
Edit: a lot of plants and corals are grown under red light. So maybe red could be more harmful for your sleep if it triggers growth.
https://www.npr.org/sections/health-shots/2019/12/15/7871389...
I struggle with migraines and am going to do a big Green Light experiment in my house for 2020.
Seeing how differing everybody's experiences seem to be, maybe this is one thing where people are just different from each other.
Thanks for posting this. Very interesting read and has made me change my buying behaviour.