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).
At first I had to keep checking the settings because I thought it had turned off. But when I turned it off it looked extremely blue and painfully bright. Even looking at a white screen I can't notice the orange tint at all anymore. It's pretty amazing.
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
Most people don’t move around significantly. One way to find this is by detecting networks: if I’m plugged into Ethernet or connected to the same wifi, I’m probably at the same place. Please do not ask me for my location.
We only prompt if your timezone offset changes (traveling), or if you've never set things up. Something in the parent's configuration is triggering "never set". We have not used BSSIDs for this because some corporate and campus users roam between hundreds of APs, so it would be much more invasive (or we'd have to chat on the network to figure out that nothing had changed).
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 think you're mistaking tension headaches for migraines. As a lifelong migraine sufferer, I can assure you they're different, and while tense neck muscles or stress can be a trigger for migraine, they're not the reason why I have them.
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 also started using redshift (linux equiv to flux) several years ago and gradually used it more, even during the day, as I also found it seemed to help mitigate migraines at least to some extent and it just generally reduced my eye fatigue.
I have a shortcut on my KDE desktop that runs this command:
/usr/bin/redshift -O 3500 -b 0.7
It instantly makes the screen easier to look at, no matter the lighting conditions. I also have a command to revert to normal color:
/usr/bin/redshift -O 6500 -b 1.0
Curiously, "redshift -O 2700 -b 0.7" is less comfortable than 3500K because it's too yellow. I think what bothers me about screens is heavy saturation in any color.
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.
I remember reading somewhere about placebo effects changing over time, but I thought that was across populations over time, not for an effect on an individual over time. Do you have more info on what you mean?
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.
I've found no difference after ~2 years of going (pretty deeply) red on all my devices and suddenly going back to filterless every now and again. I can't believe how blue it looks, but then I adjust.
I continue to redfilter out of neurotic superstition. Like maybe we'll all have a macular degeneratory epidemic in the future because blue light was our generation's asbestos or cigarettes. Have you seen the new Blade Runner? They have yellow lights everywhere. Pretty sus, imo.
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?
I agree, the lowest brightness on Pixels is still too bright. I used to use the "Lux" app to reduce the brightness even more, but IMHO Lux has so many buggy features that it's not worth the trouble. I just want a manual slider. Are there any simple Android apps that can manually reduce the brightness beyond the minimum?
There are apps that filter all colours equally, but it's not nearly as good as reducing the backlight brightness would be. When 0-255 is remapped into 0-127 (or lower), you're inherently going to start losing the ability to distinguish colours. Unfortunately, you lose contrast a lot faster than you lose brightness via that method, so it's not very useful.
I wonder if a physical filter for the screen might be the simplest method.
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.
TV programs are designed to get your attention. Try watching college lectures instead. I'm still not sure what Russian formalism is actually about, but boy it sure is a great sleep aid.
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!
How It Works and Ancient Aliens do the job for me. If I watch either of those after I've just had dinner I don't stand a chance. I'm knocked out by the end of the episode.
I use the trashy aliens docs on amazon prime.
the "customers also watched" has been great for discovering all sorts of wackado theories on human origins.
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.
One possibility is that some people are more reactive to blue light than others. For me, the blue light versus non-blue light difference is really striking.
Another issue is that, as others have noted, a lot of people's experiences are with Flux, but Flux is an incomplete solution to the blue light problem. I use a Macbook Air: Flux changes the color temperature of my screen, but directly below my screen is a backlit keyboard which is very, very blue. It was a big turning point for my sleep health when I got a pair of blue light blocking glasses which handled this in addition to the screen blue light.
Did you get the glasses because you believed they would help your sleep, or for other reasons? One solution to why so many people talk about the improvements with Flux or glasses could be a simple placebo affect.
I got the glasses because I hoped they would help my sleep--I'm not sure I would say I believed they would.
I totally agree that it may be the placebo effect. However, I feel that it's important to note in discussions of the placebo effect that it's fairly irrelevant whether an intervention works because of the placebo effect or some other reason--what matters is whether the intervention works. And this one does, at least for me.
If an intervention only 'works' because of the placebo effect, than that intervention doesn't actually work and there is no reason for someone else to use it. If my sleep is improved by listening to death metal with the volume set to high, then good for me and I can continue doing it, but you probably shouldn't copy me, and may explain to people that they probably shouldn't buy my 10$ death metal sleeping app.
Note: I'm not accusing you of trying to sell something, I hope my comment doesn't come up that way.
On the contrary: if it works it works. Just because it's a placebo doesn't mean it only works for one person. The only reason we know that the placebo effect exists because we can show in multiple studies that certain placebos work on a lot of people. In fact, some placebos work better than other placebos[1].
Of course, there are pitfalls. It's important that doctors not lie to their patients, because patients need to trust their doctors, and patients need to be able to make informed choices. And as you pointed out, it's obviously wrong to sell a placebo as if it were not a placebo. But even this doesn't mean placebos are useless: some placebos work even when you know they are placebos[2].
There are many cases where placebo performs better than nothing, and it would be foolish to not use this effect to improve our lives.
From what I've read, the placebo effect is still mysterious, and the only place where it is consistently found to help is in pain perception. Outside of this, there are some studies which show improvements in placebo when compared to no treatment, but other studies ([1][2][3]) find no improvement or only perceived improvement - e.g. the patient feels that they slept better, but in fact they slept the same amount and it took them just as long to get to sleep.
So, overall, it's not clear whether the placebo effect is a real effect that placebos have on patient health, or whether it is an artifact in the data, e.g. due to reporting errors, especially in studies which are not double blind (where the researcher may be biased themselves in the way they are collecting the data). There are also many studies which compare an active substance to a placebo treatment but have no data about patient response under no treatment, which is itself not necessarily 0 [2].
Edit: added a [3] that is explicitly about insomnia - placebo was found to improve subjective perception of sleep quality, but not objective measures (sleep onset latency).
That's interesting, and it's good to know that my sleep improvement might be perceived rather than actual.
That said, this is just evidence that the placebo effect may not apply in this case. It's not evidence that if interventions only work due to the placebo effect, they don't work. You've convinced me that I'm probably not experiencing benefits from the placebo effect in this case, but that conclusion is unrelated to the conclusion of your previous post.
I'll also add that your assertion that pain perception is the only thing that responds to placebo is incorrect. Placebo is effective on a wide variety of things, including weight loss[1], itching[2], asthma[3] and warts[4] (that last one surprised me).
There's also lots of cases where placebo makes things worse, such as people responding to placebo poison ivy[5].
Finally, there's lots of cases where things which were used in studies for placebos turn out to be active. For example, a study of insulin and chromium in sugary foods for diabetics used apple pie as a control source of sugar, but discovered that the cinnamon in the pie produced a larger effect on insulin resistance than the chromium.
I'll add a bit to @kerkeslager response in stating that a placebo is something that works because you are told it will work. Your example of death metal would only be a placebo affect if someone told you that listening to death metal will help your sleep and then it did. If you are just a hard core rocker and got used to listening to death metal to sleep and now you find that without it you don't sleep as well, that isn't the same thing as a placebo affect.
But I am interested in what a death metal sleeping app would actually look like. Of course I would have to ask if it's needed in the market place (does it create value), as opposed to just playing my Demented Ted playlist.
> I'll add a bit to @kerkeslager response in stating that a placebo is something that works because you are told it will work
Yes, that was part of my initial point - to the extent that placebo exists, anything can be turned into a placebo with enough marketing. Avoiding blue light could help with sleep quality. Adding more blue light could help with sleep quality. Faith healing could help with sleep quality. Homeopathy, traditional Chinese medicine, ayurvedic medicine, leeching, blood-letting etc. If it only depends on you believing in it, but it does help, I would recommend the cheapest possible remedy that you can bring yourself to trust, and that doesn't have a proven anti-effect (coffee therapy for curing insomnia may not be an effective treatment).
I also detailed some skepticism of the placebo effect in another response here.
> If an intervention only 'works' because of the placebo effect, than that intervention doesn't actually work and there is no reason for someone else to use it.
Absence of proof doesn't mean proof of absence. So it may or may not be placebo, but it's an interesting data point for me (just bought blue blocker glasses, plan to try out. At $15-20 per, it's a no-brainer even if it doesn't work out).
I agree that they do seem like a no brainer, I don't have them for sleep but I did buy a pair of the glasses for looking at computer screens, and they do seem to help when I'm spending too much time in Word and Excel.
As @kerkeslager states below, this is just not true.
I think the best way to understand a placebo effect is this:
If I don't give 100 patients a drug to cure a cough and 30% stop coughing, I have a baseline.
If I give 100 patients a drug to cure a cough and 90% stop coughing I can say my drug is effective.
If I give 100 patients a sugar pill and tell them it will cure a cough and 60% stop coughing I can say this is better than my baseline and the placebo effect is present.
If I give 100 patients a sugar pill and tell them it will cure a sneeze and 60% stop coughing and nobody stops sneezing, then I need to revisit my previous study to find out if sugar can cure a cough. But in this case you don't have a placebo effect because the patients believed the pill was to address a sneeze.
Any comparative study with a decent methodology would detect the problem of differing sensitivities per person (by checking the standard deviation among other things).
The problem, as another comment points out, is that this study was done on mice. To me it removes all possibility of applying its conclusions to humans, because our sleeping habits don't seem similar at all.
> Any comparative study with a decent methodology would detect the problem of differing sensitivities per person (by checking the standard deviation among other things).
To be honest, I've never tried--I always assumed that I'd want to be able to see the keys in order to place my hands before I touch-type. Maybe I'll give it a go.
Old Apple keyboards used to have the bumps on D and K, but I don't think I've ever seen a keyboard without any bumps at all. It's definitely not a US only thing.
The title should probably be edited to include 'in mice'. If it's editorialized, it should be done right. Mice sleep during the day, they are nocturnal. I would trust sleep studies on mice way less for extrapolating to humans... I mean, it's great that this is studied. But they should probably use apes.
Also, waiting for all the anecdotal comments 'Yeah, it makes sense. Best sleep I get is after I use my devices without f.lux' to flow.
Not sure how much conditioning this is but I tend to be more focused and task oriented in >4000K color temperature. I can't really stand residential settings >2700K (unless it's some isolated work room like a garage, laundry etc). So the people that work on that lighting design stuff seem to know what they are doing, at least for me.
It doesn't help with the desire to actually go to bed, but another anecdote is the darker the room the better the sleep. Most window dressings are decorative and designed to be somewhat translucent. Add a blackout cellular shade or curtain. Eliminate any displays, cover power LEDs etc.
It seems like they are significantly more awake during the day. I only did minimal research, so be weary to trust me. But regardless, I would find this study to be essentially useless in determining how blue light affects the sleep of humans.
The night modes of my displays (iMac, MacBook Pro, iPhone, iPad) definitely help me be a bit more relaxed compared to staring at them in their normal mode, especially during the nights.
That being said, reduction of blue light does not help that much either. I found that a much stronger contributor to my staying awake is the light of the screen itself. I found that if I am in the mood to nap during the afternoon, the smaller difference between the my phone's display light and the ambient light helps me fall asleep much, much quicker compared to when I am staring at my phone with all lights turned off. The difference is much more pronounced and obstructs my brain's desire to doze off.
So IMO the reduced blue light has an effect. But it might not be that big indeed.
OK intuitively there is indirect and direct sunlight. Based on my highly unscientific personal experience I'd guess the body can tell between direct daylight and sunset spectra (both warm) and indirect daylight and twilight spectra (both cool). Electronic blue lights after lots of f.lux seem quite annoying, so I'd guess they are more like daylight.
Relatedly it always bugged me when I was little that blue lights seemed "white in the middle with turquoise then finally blue exterior". Blue lights just couldn't be both bright and saturated very easily. I wouldn't be surprised this is related to the daylight-ness vs twilight-ness.
Ah, all the better. So the day is neutral/cool or quite cool (direct or indirect) and the evening is warm or that twilight blue which https://www.flickr.com/photos/bob_81667/25663810348 is just the same indirect thing but darker?
Would seem like coolish is any time of day depending on brightness, but warm is definitely evening.
When the sun goes down, colour temperature is determined by the alternative light source. For most of the past 100,000 years, life on our rotating planet has relied on moonlight (cold) or firelight (warm) to see at night.
Incandescent lights (Edison light bulbs) are a bit cooler than the candles and (most of the) oil lamps they replaced.
Bright cold (high Kelvin rating) lighting at night is a very modern invention:
By "twilight" I meant the atmospheric scattering from the sun just over the horizon. Is that roughtly same color temperature as the "5,000 Horizon daylight"?
Lots of good comments on the quality or compatibility of these results for humans. But I'll add: I don't care. Even the placebo effect of the night time mode on my screens has a calming effect and signals the day is winding down.
I agree, blue light, close by (so my monitor more than the TV) does make me feel more awake. Could be placebo, could be trained behavior (as in red light makes my body think sleep), could be that this study is not transferable to humans. Or any combination of these :) I'll happily stay with f.lux :)
2010: Study says caffeine is unhealthful
2011: Study refutes 2010 caffeine study
2012: New study says caffeine is unhealthful
2013: New study says caffeine is safe
2014: Etc.
I reliably get restless leg syndrome when there is a blue LED left on in an adjacent room with its light leaking in to my bedroom. Other triggers: too much caffeine late in the day and dehydration.
The yellow LEDs in the room don't bother me when I forget to turn the device off. And the red clock projected onto my ceiling doesn't bother me either.
I used to sleep fine with blue LEDs though, so maybe it's just different for different people, ages, environments, and/or other factors.
I wonder how a human raised in a home with incandescent vs fluorescent vs other colors of light bulb would react. I have to assume this is at least partially a learned response.
I’m curious if they tested the wavelengths that wood fires give off as well as moonlight—this would most closely match “natural” light exposure post twilight.
It may not be disruptive to our sleep patterns, but surely I find extremely annoying if abused like it is today. At over 50 I have no sleeping problem, at least not more than I had before the digital age; blue light just make me nervous, and I recall hating blue leds thrown in every appliances just because they're dirt cheap long before people started talking about any potential harm.
However the science turns out, I still recommend flux/redshift just for the reduced eye strain. I don't even bother with scheduling it to shift throughout the day, since I've never noticed any impact on my sleep.
It may be "not as disruptive" for sure, but since I began to use night light mode both on my phone and laptop, I began to fall asleep in 10-15 minutes after going to bed. Also I use warm light LEDs intstead of cold ones.
Anecdotally, it is definitely highly disruptive to me. I have red light shifting in all my devices and I bout some blue light filtering glasses and that does make a difference in how quickly I fall asleep.
OFFTOPIC: Isn't blue light still best to be avoided as much as possible, as it damages cells in the eye, causing macula degeneration. Please correct me if I'm wrong.
As a society, we like to focus on presumed "easy" fixes. It's not the sedentary lifestyle, chronic sleep deprivation, and massive amounts of caffeine we drink that disrupts our sleep, no, it's the color of light. Never mind that the effect is apparently so small that science has yet to prove conclusively that it even exists, this is the thing that is killing everyone.
The number of high profile research reversals over the past decade or so has been extraordinary. At this point, I'm forced to regard most published findings as simply false unless strongly supported by intuition and repeated studies. More and more, I feel like the process of science has decided all the "signal" the natural world is giving us and that now we're just interpreting noise, at least as it pertains to studies on people.
There's an astounding amount of nonsense popularized in mass media where they take the results of these studies and promote it as the gospel truth, without noting the caveats - tiny sample size, only studied in mice, effect sizes, etc, etc. By the time the game of telephone has relayed the story to the public via the local TV news puff piece, it has been distorted so heavily that it becomes complete nonsense.
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.