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Science

Seeing Blue At Night May Not Be What's Keeping You Up After All (sciencealert.com) 52

Posted by EditorDavid from the light-sleepers dept.
We already know that a precise range of wavelengths within daylight triggers a light-sensitive photoreceptor in the back of your eye, causing the body's internal clock to reset.

Those receptors are called "intrinsically photosensitive retinal ganglion cells" (or ipRGCs), according to Science Alert — although the actual color is perceived by some nearby cones (which then send information back to those rceptors).

But are our bodies really affected specifically by the perceived color? Chronobiologist Christine Blume investigated with a team from Switzerland's University of Basel and Germany's Max Planck Institute for Biological Cybernetics: Modern scientific wisdom advises us to avoid devices that emit a significant amount of blue radiance, such as our smartphones, computer monitors, and tablets, when we ought to be wrapping ourselves in darkness and resting. There's perfectly sound reasoning for this — the ipRGCs in our eyes react to short wavelengths of electromagnetic radiation, roughly 490 nanometers in size... Given blue light scatters from the sky during daylight hours, it makes sense our eyes would use this wavelength as a cue to mark the beginning and end of sleep time...

Yet University of Basel chronobiologist Christine Blume had her suspicions that the way a light's mix of wavelengths influenced the color-reading cones could mean there's more to the phenomenon than meets the eye. "A study in mice in 2019 suggested that yellowish light has a stronger influence on the internal clock than bluish light," says Blume. To resolve whether the way cones perceive a range of wavelengths carries any weight in how the blue-triggered ipRGCs function, Blume and her team recruited eight healthy adult men and eight women in a 23-day-long experiment. After habituating to a specific bedtime for a week, the volunteers attended three visits to a lab where they were exposed to a constant controlled 'white' glow, a bright yellow, or dim blue light for one hour in the evening...

None of the analyses revealed any indication that the perceived color of the light affected the duration or quality of the volunteers' sleep patterns. Instead, all three light conditions caused a sleep delay, suggesting light in general has a more complicated impact than previously thought. That's not to say ipRGCs aren't affected by 'blue' wavelengths of light. Rather, white light that is packed with blue waves but stimulates cone cells into seeing yellows, reds, or purples could still affect our sleep cycles. Similarly, light that looks blue but isn't intense enough to provoke the ipRGCs into functioning might have little influence over our body's daily rhythms.

Phones of the future may one day allow us to switch into a night mode that we don't perceive in warmer tones.
Thanks to long-time Slashdot reader schwit1 for sharing the article.
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Seeing Blue At Night May Not Be What's Keeping You Up After All More

Seeing Blue At Night May Not Be What's Keeping You Up After All

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  • Shocker (Score:3)

    by timeOday ( 582209 ) on Sunday January 14, 2024 @01:43PM (#64157993)
    These simple psychological discoveries with immediate impact that had somehow never been previously noticed outside the lab - they almost never hold up.

    • Re:Shocker (Score:5, Insightful)

      by XXongo ( 3986865 ) on Sunday January 14, 2024 @02:09PM (#64158083) Homepage
      More noteworthy is that the popularly-shared conclusion is that blue light from your devices-- laptop, phone, tv screen-- is the problem, which somehow fails to take into account that the intensity of the light from these screens is literally three orders of magnitude less than sunlight.

      Exposure to light may reset your circadian rhythms, but orders of magnitude matter.

  • That's true.

    Last night it was the large bowl of chocolate chip ice cream I ate at 9pm.
    The night before it was a fear of An Orange Man becoming president of the worlds most powerful country.
    Last week it was the six-pack of beer I drank in the afternoon.

    Or was it? Perhaps it was just the blue light ...

    • I'll be up all night tonight thanks to rum and Pot Noodles.

  • Doesn't surprise me (Score:4, Insightful)

    by Baron_Yam ( 643147 ) on Sunday January 14, 2024 @01:46PM (#64158001)

    The human body will generally adjust its circadian rhythm based on light exposure (primarily, there are other factors).

    Somehow I doubt there's an evolutionary pathway where the light signalling would be restricted to a particular frequency range of visible light.

    Stay away from bright light when you're planning on going to bed. You don't need to filter blue light, you need to dim the lights in general whether they're room lighting or a display screen.

    • Somehow I doubt there's an evolutionary pathway where the light signalling would be restricted to a particular frequency range of visible light.

      I'm not saying I believe it, but it's not that far fetched an idea.

      The proportion of different frequencies of light getting refracted/reflected by the atmosphere changes with the angle of incidence of the light.

      Blue is one of the dominant frequencies during the day (to verify look at sky during day).

      All of our photoreceptors only respond to specific frequency ranges.

      Specialization of function along those lines should not come as a surprise.

    • Re: (Score:2)

      by acroyear ( 5882 )

      This has been my approach. Bit by bit, i keep dimming the lights throughout the evening. fade down the monitors and go into dark mode, dim the tablet i'm reading from, keep turning off any light not needed, but not all at once.

      Sure enough, i'm usually asleep within half an hour of being in bed.

      The "night mode" orange actually kept me up because it just made it harder to read at all - i was stimulating myself overworking trying to interpret the colors i was seeing given the orange filter.

  • I like where this is going -- but can they redo the study where the participants wear glasses that filter certain frequencies of light (e.g. the kind found in laser labs that can specifically filter 480-500nm light); one group wears glasses that filter blue light, another yellow light, etc, and STILL use their devices for an hour before bed? Sure your instagram feed'll look like a bad 3D 80s movie while lying in bed, but it'll solve more clearly sleep patterns as a function of light frequency rather than th

    • Re: (Score:2)

      by XXongo ( 3986865 )
      well, people don't usually wear glasses to bed, so this may disrupt sleep more than just changing the color of ambient light.
    • I'd settle for a study where they didn't use the subjective reported perception of colour as one of the independent variables...

  • "light in general has a more complicated impact than previously thought."

    But not that thought previous to that. Light. Period. That's what affects diurnal rhythm. Everyone knew that until the blue man group came and issued their meme.

  • My insomnia story and ambien (Score:4, Interesting)

    by iAmWaySmarterThanYou ( 10095012 ) on Sunday January 14, 2024 @01:56PM (#64158027)

    10+ years ago I had extreme insomnia. I went for several months sleeping in short bursts around the clock, never more than 20 minutes at a time. Would fall asleep at random times. Etc etc. Bad. Really bad. Eventually I went to world famous sleep clinic where I underwent tests, etc etc for a few months until they were able to help me get back to normal.

    Things that didn't matter:
    Blue light
    Using tv or computer screen before bed
    Eating/deinking (or not) before bed
    Trying to go to bed at a particular time

    Things that did matter:
    Caffeine intake
    Stress
    Having a set time to get out of bed 7 days a week

    I did not have sleep apnea so cpap machine wasn't for me. Ymmv.

    Before the sleep clinic helped me I did take ambien prescribed by random GP doctor. If you have trouble sleeping, DO NOT DO THIS. Ambien does help but it's a trap. Your body will quickly adjust and require ever higher doses. Once you're above the FDA limit (which only took me 2 months to hit) ambien becomes toxic to your system. I was at triple FDA when the sleep clinic doctors freaked out and told me to get off it. I was able to go to zero on my own but the withdrawal symptoms were pretty bad. The symptoms I had from my toxic dose were also pretty bad. And oh yeah, 3x wasn't enough to consistently sleep. People who go higher than where I was need to go to the hospital for a week where they flush your system on an IV drip.

    Ultimately, what fixed my sleep issue was stupidly simple. Set alarm. Get up. Never hit snooze. It doesn't matter when you go to bed. It matters when you get up. If you consistently get out of bed every single day at the same time your brain will adjust and self correct. (This assumes you don't have other real medical problems).

    • Things that did matter:
      Caffeine intake

      Same here, I slept much better once I stopped having a triple espresso before bed!!

      Though more seriously even black tea in the evening can screw with my sleep.

      Ultimately, what fixed my sleep issue was stupidly simple. Set alarm. Get up. Never hit snooze. It doesn't matter when you go to bed. It matters when you get up. If you consistently get out of bed every single day at the same time your brain will adjust and self correct. (This assumes you don't have other real medical problems).

      I think a regular bedtime helps, particularly turning off lights.

      But my rule of thumb is actually the opposite to yours. I'm useless when tired so if at all possible, sleep until rested.

      The other thing that helps me sleep is exercise. Just sitting around I think I have enough energy for a 26 hour day cycle. But if I'm active it's much easier to get to

    • Re: (Score:2)

      by chefren ( 17219 )

      This is very true, and you need to stick with it also on weekends. Go to sleep and wake up at the same time (+- 30 minutes) every day, and your biological clock will help you sleep. You can use Melatonin as support if you can't go to sleep at your regular time.

      Definitely don't drink any coffee in the evening or even late afternoon (experiment to find out just how sensitive you are to coffeine). You can always drink decaf or herbal tea in the evening instead if you want your warm drink but don't sleep well i

    • Re: (Score:1)

      by Sven77 ( 5290317 )

      Will you please share the name of the sleep clinic that helped you?

  • Study uses bad metrics (Score:3)

    by JoeDuncan ( 874519 ) on Sunday January 14, 2024 @02:08PM (#64158075)

    None of the analyses revealed any indication that the perceived color of the light affected the duration or quality of the volunteers' sleep patterns.

    Srsly, WTF. Do people not know how to properly design experiments now?

    Why the F would you conduct this study using self-reported values as one of the independent variables?!?!?

    JFC - they know the frequency mix of light they were using!!! Just use that for FFS!!!! Self-reported "perceptions" are notoriously garbage input

    • It was also conducted with just 8 participants over 23 days? I think I'm not going to do lifestyle changes based on that kind of evidence just yet.
      • Evidence now shows that SlashDot has done more research on this today then Christine Blumes so called research team did on the entire project.

    • Re: (Score:2)

      by ceoyoyo ( 59147 )

      Perception is very important when you're dealing with human behaviour. The placebo effect is a thing. The subjective perception of the colour of light could be particularly important because your eyes naturally white balance, meaning a constant colour temperature screen will appear much bluer against warm lighting we tend to use in our homes than against the cold light of daytime sunlight and the crap we tend to use in offices.

      Anyway, that's not what they did. The actual experiment used light that was calib

      • Perception is very important when you're dealing with human behaviour.

        Agreed, but if you are trying to determine whether blue light keeps you awake or not, and you shine blue filtered light on a bunch of subjects, they all get sleepy, but everyone of them reports "perceiving" blue light - then your study is entirely fucking useless.

        Anyway, that's not what they did.

        No? Well, the reporting is shit then (no surprise there)

        The actual experiment used light that was calibrated to have the same effect on the ganglion cells while having different short and long frequency content.

        Really? LOL That's even worse ! Do these people even know what they are doing?

        If the ganglion cell outputs were their dependent variables, but they arranged their study so that their depende

  • I use RedShift [maketecheasier.com] on my Linux box and it really helps.

  • ... it is called "off", and usually accessible via the power button.
    And given how quickly the natural light near the equator changes from "still pretty bright" to "pitch black dark", I doubt humans have problems sleeping from looking on some phone screen _before_ they go to sleep. The phenomenon rather seems to be that some people feel enticed to look at phone screens _instead_ of sleeping.
  • 16 individuals, three measurements... That's not a lot of data to draw any conclusions from. How on earth did they even get the article published in the first place?

    • > How on earth did they even get the article published in the first place?

      We've learned how journals work over the past few years and it's not good.

      Having people stop watching TV and social media and working after dinner would be bad for corporations.

      Don't forget a sugary desert before bed!

  • The study is good though looks to be extremely limited (8 participants, really?) but in my own experience I just hate the blue color when it's getting dark and it gets so much better to look at the screen when the amount of blue is reduced.
  • I'm hoping to build my own house in several years and do it in a way that allows for a lot of home automation. My goal for sleep preparation is to set an expected bed time (we'll see if I'm capable of sticking to it) and then have all of my overhead lights programmed to begin slowly dimming about 30 to 45 minutes before the expected bed time until they reach a pre-determined minimal level. I'd also like to see if I can integrate my devices to dim their screens on the same schedule as well. For the mornin

  • Seeing Blue At Night May Not Be What's Keeping You Up After All

    Seeing some types of Blue [urbandictionary.com] might keep you up -- for a while anyway.

  • I'm colorblind (as are 10% of all males)

    Somehow I manage to consistently sleep a solid 7-8 hours each night, better than anyone I know. I used to think my sleep habits were due to my extraordinarily clear conscience, but now I know the truth. People worry to much about color

  • The only reason I've ever used any of the "night shift" type display adjustments was to make them look less harsh under normal 2700k home lighting in the evening. Of course, I do know some people who have those awful bluish bulbs [youtube.com] in their home and for them there'd be no need to adjust their display's color temperature in the evening.

  • Filled with joy I can switch back to the default theme for my beloved file manager and editor.

  • Just from the abstract it sounds like they rigged the parameters a bit.

    If they wanted a fair test, one that focuses on frequency, they should have used 3 light settings of identical total flux and a single wavelength.

    Comparing a "bright yellow" light to a "dim blue one" is certainly confounding their test for little gain.

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