Study Shows Blue Light Better Than Warm Light at Night


Ever since a flawed study was published several years ago about how using an iPad at full brightness before bedtime can make it take longer for some folks to fall asleep, the war against blue light has really taken off.

App developers and ebook reader manufacturers jumped on the anti blue light bandwagon by offering color-shift technology enabling users to switch from a blue light to an orange/yellow light for nighttime.

But now a new study suggests that exposure to blue light may actually be better than warm light at night.

“Our findings suggest that using dim, cooler, lights in the evening and bright warmer lights in the day may be more beneficial,” says Dr. Tim Brown, from The University of Manchester.

“We show the common view that blue light has the strongest effect on the clock is misguided; in fact, the blue colours that are associated with twilight have a weaker effect than white or yellow light of equivalent brightness.”

When tested on mice, the study showed that blue light produced weaker effects on a mouse’s body clock than yellow light set at the same brightness.

This is the exact opposite of the common opinion that has been circulating in recent years. It turns out exposure to blue light at night might not be as bad as previously thought. In fact, blue light might just be better than warm light.

Either way, more research needs to be done before proclaiming the evils or benefits of blue light.

Here’s the link to the report at Current Biology for more information.

via: Manchester UK

29 Responses to “Study Shows Blue Light Better Than Warm Light at Night”

  1. Well doesn’t that news just frost your bulbs? Anybody got a link to that flawed study? And, how do either of these light colors compare to using dark mode where the background is black and the print is white?

  2. I’ve written, rewritten, and deleted while paragraphs here, but basically this is one study against many others. The science still overwhelmingly supports blue light filters.

    • I'm Reading Moby-Dick Reply December 29, 2019 at 7:28 pm

      This is an awesome study. However, it doesn’t invalidate other studies. Here’s the real title:
      “Cones Support Alignment to an Inconsistent World by Suppressing Mouse Circadian Responses to the Blue Colors Associated with Twilight”

      >it’s mice
      >it probably applies to some degree to all mammals
      >but mice are mostly nocturnal
      Wikipedia: “Primarily nocturnal[3] animals, mice compensate for their poor eyesight with a keen sense of hearing, and rely especially on their sense of smell to locate food and avoid predators.” (mice are pretty cool)
      >humans have a keen sense of sight (please ignore my spectacles)
      >humans are primarily not nocturnal

      Further complicating things, I think humans may have evolved the ability to deal with firelight.

      Even further complicating things, some humans are definitely night owls, while others are larks.

      Even further complicating things, iPads and e-books fill the center of vision, meanwhile there are options for illuminating rooms. This means you have these variables:
      >size of the tablet (let’s keep it simple and just think of it as % of the field of view)
      >we will assume text is perfectly distributed
      >we will need to apply rules of eye movements to create a cloud that models how it impacts the retina
      >We then need to try out about 12 different ambient lighting conditions
      >And about 12 different tablet lighting colors
      >I figure, 6 colors should be enough (RGB + CMY) + each of the 6 as tinted white (eg red-white, green-white, blue-white, cyan-white, magenta-white, yellow-white)
      >this is 144 groups
      >assuming we just use, say, a 10″ ipad
      >we should probably also do some other sizes, though…
      >we might need more groups to account for brightness levels in the room
      >we could wind up with like 1440 groups, to account for brightness levels
      >but we also need controls, how about listening to audio books, while instructed to keep eyes open, looking around in a room illuminated in the 120 possible ways (12 colors * 10 illumination levels)
      >So now we’re at 1560 groups
      >And we also need to think about age, as young people and old people, and those in between are very different in terms of eyesight
      >Do we also have various caffeination levels/habits? How closely do we control for this? Do we imprison a whole city for this study, and stick them in cages with like a treadmill, water bottle, and caffeine dosing system?
      >The study needs maybe 5000 groups to be definitive
      >This is an impossible study
      >It will never happen
      >We will never know
      >I didn’t even mention that we’d better have different groups for various eye colors, in case it matters
      >I didn’t even mention we’d need to have groups with certain sun exposure to the skin and others not, maybe different levels, maybe various schedules. People who sunbathe might get a different result from people who wear pants & long sleeves too. It might matter, because people might have evolved different responses based on amount of clothing (clothing was a necessity in the ice age).
      >And I’m probably forgetting a bunch of stuff
      >Like that maybe certain frequencies of light, or combinations of frequencies might have a specific effect
      >and that the direction of the light might matter (compass-wise)
      >And what about habituation?
      >And what about music, in its varieties of styles, themes, bpm?
      >And what about the role of content of the thing being read (eg, is it a mystery, in the horror genre, a newspaper, a history of doorknobs) (this matters because of radically different activation of the amygdala)?

      This said, what’s your theory about it? It’s safe from ever being contradicted anyhow, since it’s impossible for science to tackle. Personally, I believe I am a wizard, and, as such, am never early or late, but always exactly on time. ht Tolkien

    • Ok thats all fine and dandy, but proclaiming “a study shows” – please, provide the link to this flawed study?

      • It was from like 10 years ago. I don’t know where the link to the original study is anymore. It was flawed because they were going out their way to prove blue light affected sleep. They only tested like 6 people with an iPad at full brightness for like 2 hours before bedtime. And even then they only concluded it took like 10 minutes longer to fall asleep. Big deal. Ever since then everyone thinks blue light is evil and is keeping them up all night. Who uses an iPad at full brightness before bedtime? I rarely go above half brightness during the day. It was a stupid, flawed study that got way too much attention at the time and it sparked the whole blue light is evil nonsense, which still hasn’t been proven to this day.

  3. When we desire to keep mares in cycle during winter months, what do we use? Blue and daylight bulbs 200 watt bulbs are the minimum.

    Why? It simulates the day which tricks the body into staying up and thinking it is summer.

    As a person with sleeping issues, the night lights on the Kobo have been helping me at night versus the day light based ones. I tracked it with my Fitbit and Withings sleep aspects and if you use me and other studies as a data point it proves it.

    Now of course not all people are suspect to blue light just like caffeine helps people sleep or has no effect, so YMMV.

  4. With my blublocker orange sunglasses that I wear in front of my CPU screen, i get sleepy at my normal bedtime. With regular white light CPU screen, it keeps me feeling awake and alert for many hours. I believe this study is flawed.

    • My experience is the same. I find a slight warm tint on my Kindle works best at night.
      The blue blocker reading glasses make using the computer so much easier.
      They’ve been a real boon when I use Illustrator. I can work longer with clearer vision than plain reading glasses. Intricate work is so much easier.

    • I hate to say it, but everyone who is saying “I use blue light filters, and I go to bed at bedtime, so therefore this study is inaccurate/flawed/wrong etc…” is practicing pseudoscience. You are textbook descriptions of the cognitive distortion known as confirmation bias.

      “I can’t see that the world is round, my experience is that Earth is, in fact, flat. Therefore, the world is flat.”

      See how that works?

      Instinctually I agree though, blue light seems to glare painfully at night. That said, I don’t ever remember having issue with it before the filters started coming out, so I’ll continue to watch with an open, scientific mind.

      Additionally, I second poster who requested supposed original flawed study

  5. This is facinating! But I’’m confused: how do they get the mice to read from a Kindle and what are their favorite books?

    • This is the best reply this far!

    • The mice have many favorites, including Ralph and the Motorcycle, Cinderella, The Chronicles of Narnia: Prince Caspian and also Narnia’s The Voyage of the Dawn Treader. To continue, The Hitchhiker’s Guide to the Galaxy by Douglas Adams, Of Mice and Men, Stuart Little, If You Give A Mouse A Cookie, and The Amazing Maurice and His Educated Rodents by Sir Terry Pratchett.
      I’d include more titles, but a slice of cheddar appeared unexpectedly from the skies and the mice stopped talking to me.
      PS I’m not sure but I think the mice enabled that read-aloud function on the Kindle.

    • Their favorite book is Flowers for Algernon 🙂

      • Aw, probably so. I can picture them evolving from Stuart Little in young mousehood to Flowers for Algernon when they grow more deep.

  6. Light has never prevented me from sleeping. I can sleep just fine in the middle of the day or under florescent bulbs. But white light hurts my eyes so my computer screens are muted with a warm hue and I use the temperature adjustments on my ereader whenever they are producing more light than is ambient. Today I had trouble scanning a QC code to get into the movie theater because my phone screen was too dim.

  7. The science in the recent study is solid. One thing not mentioned is the importance of dimmed light versus bright light.

    Dimmed blue light seems to be much better than bright orange or yellow light.

    I’ve always suspected brightness was more the culprit than the wavelength. I’ve noticed I sleep fine with a tablet or smartphone well-dimmed

  8. The blue light filters trigger my migraines in a couple minutes. Leave on the blue light and filter out the red, and my head is fine. So the only way the blue light filters get me to sleep is by causing me high levels of pain and medications to lower it enough I can sleep it off. Pretty sure that wasn’t how it was meant to work. Personally it depends on what I am viewing and turning the brightness down. I am also one of those people who has caffeine as a relaxer rather than stimulant. I tend to have all the rare side effects, like maxalt causes me to subconsciously hold my breath to reduce the movement where it amplifies my migraines rather than reducing them.

    Honestly, night mode where it turns the background black or the settings that let me choose a sepia tone (a mix of blue and brown so very little red in the mix) work fine and let me drop off so long as I don’t get wrapped up in what I’m reading. Those colors reduce the strain caused by the higher brightness and brightest white over the majority of the screen. I always felt like the red light studies were screwy since it was a warm red which tends to be a more energizing color.

    • I’m not downplaying your lived experience, just correcting a scientific inaccuracy. Blue is the more energized color. As colors move from red to violet on the spectrum they carry more energy. That’s why infrared is warm, but ultraviolet causes burns.

      I’m always amazed by what causes migraines. It seems to be different for everybody.

  9. Usual bollocks surrounding technology.
    At 78 I find my warm Oasis suits my worn out eyes best
    Blue white pink or green – it’s good content that keeps me awake.

  10. I don’t know what kind of LEDs are in my Voyage, but I’m feeling like reading with the background light rather than under a lamp right before going to bed is improving my sleep. It helps to go to sleep and in the morning I feel better rested and refreshed.

  11. The less light, the less stimulus. Black background with beige letters works great for me. Kobo lets me do it… PoketBook don’t.

  12. This could turn out to be true, but more importantly, a single study doesn’t “Show” anything unless it’s the only study on a subject. This has no sources, no link to study, no identifying reference at all to the aleged “flawed study”. So i call ClickBait on the article – unlikely to be journalism, more likely to me social media.

    • As noted in the referenced article, the study was published in Current Biology and was funded by the Biotechnology and Biological Sciences Research Council. Here’s the link to the PDF. I also updated the link in the article.

  13. Probably irrelevant, BUT…
    What about Blue light from the moon?

    As for me, i find it QUITE pleasing to stare at the moon at night, wouldnt that be just a reflection of the Sun and its waves?
    I wonder how much blue light is actually emmited by the moon.

    Its most probably a placebo, but staring at the moon before bed makes for a better sleep (for me)

    Ill just ask for a 2020 KOBO with moon light, rather than warm light, jk

    • Someone who comes out with another e-reader should totally rename it to “moon light” instead of comfort light. I approve since I have a fondness for anything with the moon.

      I never paid attention to the affects of moon on sleep, but it makes sense it wouldn’t cause people to stay awake since we are not nocturnal for the most part.

  14. I'm Reading Moby-Dick Reply December 31, 2019 at 2:06 am

    I tried this last night. I stayed up all night LOL

    I used a blue color filter on my ipad to have nearly pure blue, while my background light was dim red (one of those cheap RGB bulbs). so my rods got lots of blue. loooooooots of blue.

    it only proves that a perfectly blue e-reader isn’t soporific, like, say, some illegal narcotics.

    doing my part hth