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LED lighting badly suppresses human melatonin production at night (sevarg.net)
434 points by bombcar 26 days ago | hide | past | favorite | 307 comments

Regarding the quoted e-book study:

> Third, in the present study, the LE-eBook was set to maximum brightness throughout the 4-h reading session, whereas, by comparison, the print-book condition consisted of reflected exposure to very dim light.

Yeah, max brightness is probably going to make an impact. I bet if you were in a room with a bright light reading a book, with an equivalent amount of lumens going into your eyeballs, you'd probably have a tough time sleeping. This study seems like it was set up to generate a certain set of results. I wonder how it would look if the quantity of light was controlled for.

Additionally, the comparisons to the incandescent spectrum and the freaking out about the blue peaks (which seem pretty small) was over the top. The incandescent spectrum contains blue, and the "peak" of the other spectra would contain an equivalent integral of blue light as compared to a slightly brighter incandescent light.

Just turn the lights down low at night and get some warm spectrum bulbs and you'll be okay.

I am disappointed that many phones/tablets don't go very dim.

From flagship to cheap, it seems that if you're in a pitch black room and check the time on your phone, the light will illuminate the whole room, even on the dimmest setting.

I actually modded my phone by putting a resistor in the LED backlight circuit, which divided the brightness by 1000 - and it was still plenty bright at night (human eyes are logarithmic, so dividing the brightness by 1000 doesn't have as much visual impact as you'd expect).

A Macbook's minimum brightness is quite bright. The thing that annoys me no end is that if you hit the "dim" button when it's at minimum brightness, it goes black - but fades out slowly and smoothly. So they're clearly capable of being dimmer, but Apple decided we're not allowed that.

I've been using https://lunar.fyi/ to go below the min brightness and also beyond the max brightness on an M1, works very well.

Such a great application. Lets me easily work outdoors in the summertime at XDR 100%

Been a while since I used a MacBook but can't you do Shift+Opt (or just Opt?) Brightness+/- for an incremental change still? Works with volume too.

I love apple devices, but man, these undocumented things make me question whose team their UI people are on. It doesn't feel like they're on my team.

The lack of discoverability isn't just limited to Apple. It's endemic. And I've heard multiple UX people claim that it's not a bad thing.

I disagree with that opinion, though. I think it's one of the worst aspects of modern UI design.

I used to feel this way, but since learning that much of the advanced functionality is unlocked by Opt/Shift/Ctrl or some combo of them + click, I find myself digging that consistency more and more. At this point if I don’t see the option I need, I know 9/10 it’ll show up when I opt+click.

90% of MacOS shortcuts I know are because I accidentally pressed them once

Even the dimmest fractional setting isn't dim enough for a pitch-black room imo

I never knew this. Thank you for the tip.

I have a small python script responsible for dimming my thinkpad + external display; it takes an argument like 'b * 0.95' for 5% reduction, reads HW + SW brightness, and lowers HW brightness to minimum before then reducing the SW brightness.

Pretty nice and the only recent change I've made is making it re-evaluate the expression based on frequency of keystrokes (so 3 brightness-down keys in 1s becomes 9 evaluated decreases in brightness).

On my Macbook Pro I can go smoothly all the way to black using the Display widget on the top right.

iOS actually has a hard to find setting that lets you make the screen super dim. It's been a lifesaver when using my phone in the evening. To enable it go to Settings -> Accessibility -> Zoom and then tap the Zoom toggle switch.

Once that's enabled iOS will now bring up a super secret popup menu whenever you double tap the screen with three fingers. From the little popup menu go to Choose Filter -> Low Light and your screen will go dimmer than is normally possible. With this on and the normal brightness mode set to its lowest setting the screen can get quite dim indeed.

There’s two settings you can use in tandem to get an OLED iPhone brightness even lower than that.

First is the zoom trick you’ve already described, then you can use the “reduce white point” display accessibility setting to apply even more darkening.

With minimum display brightness, low-light zoom mode and white point reduction set to 100%, the display gets very very dim. If you do this in normal lighting conditions, the display is basically impossible to see.

> Once that's enabled iOS will now bring up a super secret popup menu whenever you double tap the screen with three fingers.

On current iOS you don't need to be in zoom and double tap. The zoom filter is also available by tapping the "Zoom Filter" setting which is 6 items below the Zoom setting in Settings -> Accessibility -> Zoom. The double tap in zoom thing is there to make it easy to quickly change the filter while zoomed.

This and the white point setting void-pointer suggested are both controllable from Shortcuts.

There is a Zoom action that supports turning zoom on, off, or toggling it, a White Point action that supports turning it on or off, and a Brightness action that supports setting the brightness to a given percentage or asking for the brightness.

I just tried making two Shortcuts, "Low Light" and "Normal Light".

Low Light:

  Turn Zoom On
  Turn White Point On
  Set Brightness to 0%
"Hey Siri, Low Light" then works. It does leave you zoomed, so you need to cancel that, but then you are left at 0% brightness and whatever Zoom filter you have set is in effect. "Turn White Point On" will set the white point reduction to whatever percentage you have it set to in the Reduce White Point system settings.

Normal Light:

  Turn Zoom Off
  Turn White Point Off
  Set Brightness to <ask each time>
That does what you'd expect. Siri asks you what brightness you want from 0 to 1. You can change that to a specific percentage if you don't want to be prompted.

PS: This only fully works on iOS. On iPadOS zoom filters only work while actually zooming, and then only apply to what is shown in the zoom rectangle. On iOS the zoom filter applies when zoom is enabled regardless of whether or not you are actually zoomed.

The white point reduction does work on iPadOS so you do get some lowering of minimum brightness but not as much as on iOS when you can use both.

THANK YOU! I have wanted this since forever. I can't believe this is locked away so deeply and inconveniently.

Yes, I use this trick. You can adjust the filter to your heart's content. But I agree with the parent here that it should go dimmer as-is and we shouldn't need this. I'm not sure how light perception works, if it's a logarithmic thing like noise, but if not, this scale should probably be logarithmic instead. Or even moreso if it already is. Because I think we generally don't care exactly how bright it is if it's bright daylight and we need to max it, but conversely care much more for reaching the dimmest levels if we're in bed (or if we don't care, we probably should according to the article).

You can also set Settings -> Accessibility -> Accessibility shortcut (at the bottom) -> Enable “Reduce white point”

Now you can triple-click lock button to make screen dimmer. I have been using this for ages, saves your eyes in the dark.

For what it's worth, as far as I understand, you actually need to activate the Zoom Controller to get the menu mentioned above.

I just tried this out. Turned on zoom, without the controller, couldn’t get the menu when three-finger double-tapping.

However, when I three-finger triple-tapped, the menu showed up.

Do you know does this actually lower the backlight or is it changing gamma or something like that. I'll try it anyways thanks

iphones are all OLED now, so there is no distinction.

On an old LCD display there are some filters that do a linear/nonlinear mapping from 0->255 brightness to 0->64 for example, leaving the actual backlight at the same brightness. The downside is that colour banding and quantization start to get really bad - and 'black' starts to look very non-black.

My older iphone is not oled so that would explain why I did not like this setting when I tried it some time ago like what you say about blacks looking out of balance. Thanks

The latest iPhone SE still has an LCD screen. It was released in 2022 and is still a current model.

Most Android devices have an "extra dim" option hidden somewhere in the buttons at the top (you might have to add it yourself from the extra buttons).

Samsung: https://www.samsung.com/au/support/mobile-devices/activate-e...

It's really dim, one time in the morning I thought the phone screen was off and it was just set to extra dim :-))

Not on my Galaxy S10 unfortunately. I have to resort to using Darker (https://play.google.com/store/apps/details?id=com.mlhg.scree...)

Thank you for the recommendation, game changer

I use a Kobo eBook reader and an iPhone X.

My iPhone can go super dim, to the point that it's hard to see in a dark room. I use no special features.

Also, Kobo's eBook readers can go very very dim, and can be comfortably read in a zero light room. The max brightness I use is 29%-31%, dependent on lighting. My reader has a fixed light, but newer ones also adjust light temperature automagically, and much more comfortable to read (got one as a present for my dad).

The Google Pixel has a number of settings for this. It has the standard slider, extra dim, night, and grayscale modes.

I always laugh when I see competition over brightness. I cannot wait for e-ink monitors to improve and wish someone would make an e-ink phone.

Edit: Those settings might be standard on Android and not actually Pixel specific.

I keep Extra Dim on at all times to lower the peak nits and to further dim the screen when using Night Light to read after dark.

The biggest saviors to my longtime night reading habits, though, have been OLED and how many websites and ebook apps have competent true black dark modes.

Dark Reader addon is good for this and works on Firefox for Android https://addons.mozilla.org/en-US/firefox/addon/darkreader/

Another solution may be to use filtering glasses. Not "blue light glasses" but an FL-41 tint, which can help with migraines, light-sensitive conditions, and circadian rhythm issues[0]. This is a pinkish or amber-ish color tint.

What I find far more concerning is the brief mention in the article about the explosion in outdoor lighting, which is massively disrupting the little remaining wildlife we have left (and nevermind destroying any hope of a glimpse t a dark sky). And there is absolutely zero reason for it other than ignorant wrong ideas that it helps traffic accidents or reduces crime (it does the opposite). Calling it cargo-culting would be kind.

[0] https://health.clevelandclinic.org/do-blue-light-blocking-gl...

One of my favorite features on my Pixel 7 Pro is the "Extra Dim" feature, especially since the Netflix app has started enforcing a minimum brightness level that's much too high in dark environments.

It’s possible to set a custom filter in iOS, which reduces the brightness even further, but only in one colour, ie red. Better than nothing.

The main issue i think is that backlights tend to flicker at low brightness.

There’s a full-color dimming filter in Accessibility -> Zoom -> Zoom Filter -> Low Light. You can assign it to the accessibility shortcut for quick access.

Game changer. Thanks so much for this.

They do... But thats down to poor design decisions.

Human vision extends from about 10^5 cd/m^2 to 10^-5 cd/m^2 [1].

Typical backlights use something like PWM to modulate the brightness. That means you need to be able to scale your backlight by a factor of 10^10 to cover the whole human vision range. And if your CPU runs at 1 Ghz (10^9), then at the dimmest setting then even being on for a single clock cycle would be a flash every 10 seconds - clearly unacceptable, and even then, few backlight controllers could handle a 1 nanosecond pulse!

The fix is to use PWM combined with settable 'modes'. The modes could be 'bright light' (using all the backlight LED's, perhaps a few watts total), and a dim light mode, which uses just one LED through a high value resistor, of just a few tens of microwatts. Your two modes have a factor of 10^5 between them in brightness. So now the PWM on your CPU only needs a resolution of 10^5, which it can do.

[1]: https://www.researchgate.net/figure/Approximate-luminance-ra...

> That means you need to be able to scale your backlight by a factor of 10^10 to cover the whole human vision range.

Uh, phones don't produce brightness that high. And the low range is "too low" for usefulness anyway. Your math is off by few factors

> And if your CPU runs at 1 Ghz (10^9), then at the dimmest setting then even being on for a single clock cycle would be a flash every 10 seconds - clearly unacceptable, and even then, few backlight controllers could handle a 1 nanosecond pulse!

CPU is not doing PWM, it's separate chip

And you can't realistically have more than few kHz of PWM frequency anyway coz of losses.

It's not really a technical problem in the first place, it's easy technically, just have 2 current sources, when you need low light you just PWM the low current one. And not "just putting resistor in series", that's extremely wasteful, or "single led" that would just not illuminate evenly.

Unfortunately at these low currents, you tend to get a tiny amount of leakage across the LED junction - just a few microamps, but trying to make a small amount of light it becomes an issue. Worse, you can't even calibrate for it because the leakage is highly temperature dependant.

shrug kindle manages.

Compare your hypothetical 10^10 range to the range offered by typical LCD monitors, where maximum is in the 300...400 cd/m² range and a minimum brightness less than 30 cd/m² is "outstanding". I.e. a 1:10 range.

You can make the side button triple click on iPhone toggle application of an accessibility setting that lowers the brightness.

This is how I activate/deactivate the “Zoom” accessibility setting with the “Low Light” filter (and the zoom level stays at 100% unless I double triple-finger tap!)

For those that don't want to mod their phone. What I do is set brightness at min + blue light filter set to max.

Some of it is probably adaptive vision.

My Pixel 6 with an OLED screen doesn't work very good as a walking light in a dark room.

Also a Pixel owner - Try wiggling the light as you walk.

Your motion sensing kicks in before either your focus or dark vision, and even if you can't "see" it, your brain can get enough information to let you navigate.

I pointed that out because it is pretty dim, I don't try very hard to use the screen as a light.

Eye patch for sleep resolve sleeping issues and is priceless

I’m really turned off by how there’s zero critical consideration of their quoted research. They’re just hammering you over the head with quantity.

Sleep is like diet where there’s virtually no scientific consensus on even the most basic things. Plenty of studies which conclude “more research is needed”, though. That leaves people free to cherry pick and go deep into the weeds with crazy the-world-is-falling theories.

Yellow light may be worse than blue: https://time.com/5752454/blue-light-sleep/

Phone before bed can be good for you: https://newatlas.com/health-wellbeing/screen-time-media-use-...

Night Shift has no effect on sleep: https://www.sciencedirect.com/science/article/abs/pii/S23527...

Diet certainly has some basic things that are agreed upon, like caloric intake affects weight gain/loss, and it's healthier to eat vegetables and fruit than meats and grains. Sure, there's a lot of argument about the specific or how beneficial some of these things are, but it's not as bleak as you make it out to be.

>’m really turned off by how there’s zero critical consideration of their quoted research

I can take a variety of stimulants which would normally keep me up all night, but 5mg of Vit K2-MK4 removes enough of the calcium from my bloodstream so that it can't amplify the effects of the catecholamines and I'm asleep within 30mins, its actually better than taking melatonin or anti-histamines.

I've been more alert and observant as a car passenger whilst on 2 NHS prescribed benzodiazepines than the person driving the car! I think sometimes its a state of mind which makes its hard to sleep.

That's interesting! Can you provide some links to evidence regarding Vit K2-MK4, its effects on calcium in the bloodstream, and how that inhibits the effects of catecholamines and leads to sleep induction?

Vit K2-MK4 Osteoblasts better than Vit K1 in my experience, ie 50mg of K1 is nowhere near as good as 5mg K2-MK4. Calcium amplifies the effects of the catecholamines which probably explains why tea drinkers prefer hard water. Military also give out tea, during and after a exercise. High Vit A and Vit D can also lead to hypercalcemia which makes you feel good. https://scholar.google.com/

Remember Thomas Pynchon and be mindful of the fact that search engines wont always give you the studies you are looking for, so you have to go back and perform the same search's weeks and months later.

I was hoping you could provide the specific studies and research you are using to make your claims. Linking to Google Scholar is not sufficient.

What are you trying to achieve? Because I could also add, your omega 3 intake can also be a factor, Omega 3 reduces the number of osteoclasts for the flip side of the bone health and also increase the size of neutrophils which will engulf bacteria which invariable destroy bones and leads to arthritis and rheumatoid arthritis. Growth hormone, either 95% of tryptophan via the kynurenic pathway or nicotinic acid on an empty stomach will increase the number of neutrophils, although medical experts will normally give intravenous growth factor aka growth hormone. Stress hormones like adrenaline will reduce the effectiveness of neutrophils (Left shift iirc) as will a B12 deficiency (neutrophil hyper segmentation). Omega 3 will increase the neutrophil size by just under 40% so that they are large enough to consume yeast cells, which makes me wonder if brewers yeast is potentially harmful. Manganese Ascorbate is also useful because much of the vit C is stored inside the neutrophils, so larger neutrophils mean high levels of Vit C, and the manganese can contribute to MnSOD to neutralise ROS inside the mitochondria and help to repair cartilage in places like knee joints.

Omega 3 also help the serotonin and melatonin in the brain and spinal fluid which also helps with getting to sleep.

When the UK govt were giving cod liver oil and malt to kids in the 50's or 60's, under the pretence of preventing Ricketts, they knew what they were doing to control future GDP and aggression levels.

Considering the Japs are experts in Vit K studies, and prescribe K2-MK4 to post menopausal women who are naturally consuming an iodine and omega 3 rich diet seafood diet and also happen to have some of the longest living females in the world, and some of the highest IQ's in the world, I think looking to them will give you more info than a typical western diet.

Just 150micrograms of T3 (Triiodothyronine - one iodine atom removed by selenium, with 80% of this T4-T3 conversion taking place outside of the thyroid gland) will half the time spent in Intensive care in hospitals. Tyrosine is the main ingredient of T3 (hormone) & T4 )pro-hormone) so your metadata for getting more tyrosine in your diet is when you start to get grey hairs.

Many govts, like the UK Govt are deliberately harming the population with their treatments provided by the health care system and what is taught at med school, which clogs up beds and pushes up house prices with the elderly who dont want to go into nursing homes. A crude example of Maslow's Hierarchy of Needs, an agenda many govt's are now following around the world.

And choline can also reduce stress levels by reducing the CO2 build up in the body and lungs. Choline is used in the alveoli of the lungs to facilitate the gas exchange, its also used in the cell walls and the connection between neurons. The more choline you consume, the better your physical performance and mental ability. Personally I found L-Alpha glycerylphosphorylcholine to be best, but yet to try citicoline which is used in hospitals for brain injuries and costs about £3k a kilo.

Like I said, what you are trying to achieve?

Yes, thank you for being rational. "Yorg, turn down the campfire or we'll never get to sleep!"

Yorg need to finish treatise on wheel. Barg turn other side.

Sleeping next to a bright fire though, is way more easy and cozy, than sleeping next to a bright LED flashlight.

The red light (and sound) of the fire has a very soothing effect, which has probably something to do that our ancestors slept next to it since ~1 mio years.

(it is still fun, just don't use a new sleeping bag, as it might get holes)

>something to do that our ancestors slept next to it since ~1 mio years

fire == safety

I'm glad our ancestors were less worried about the quality of their sleep and more worried about what beasts might attack them during the night and using fire to keep them away, otherwise we may not be sitting here discussing how LED lighting impacts sleep quality...

actually, infrared light from campfires improves sleeping quality because it triggers melatonin production in the brain. In contrast, blue bright light triggers cortisol production.

Reminds me of that joke about a study where they shoved 20 joints into a chimpanzee’s mouth and then proclaimed that marijuana is very bad.

This. If I set my reading devices to maximum brightness, I can basically use them as flashlights.

When you wake up at night in pitch dark, a Kindle does already a perfect job to help navigate around - and won't hurt your eyes either.

And yet there are all those other datapoints that also support the central thesis that you aren't cherry-picking here. So perhaps the author's point stands?

I think OPs point is people tendency to use LEDs in way that is bad for melatonin production is not the same as LEDs being inherently bad for melatonin production as the title suggests.

Many LEDs have fine color spectrum and brightness setting and people should take those capabilities into mind when purchasing, especially for lights they will be using in the evening. Personally I’ve invested in hue lights and have them configured to dim and redshift as bedtime approaches.

Right but this is a false dichotomy, LEDs are both inherently bad AND put to uses that enhances their detrimental characteristics.

Uh, just no. LED lighting have modes of working that can be bad. You just need to be way more picky and knowledgable with LED lights which is hard for most customers, vs "just buy an incandesent bulb"

Nice "well actually" there. So is the proposal consumers perform their own spectrographic tests before making a purchase or can we just go with "leds are bad" given the overwhelming majority of the products available on the market demonstrate harmful characteristics with no clear way of discerning which are the outliers at time of purchase?

> Nice "well actually" there.

Learn to fucking read. I literally outlined problem in my comment:

> You just need to be way more picky and knowledgable with LED lights which is hard for most customers

And literally wrote that it is a problem to most customers.

So "well actually" fuck off

So you start with just no and then proceed to argue my point for me? Weird flex but ok. Anyway it's nice to see the quality of discourse hasn't degraded on HN over the years.

Wasn't that also the study where the ebook condition used an iPad, not an e-Ink reader?

Yes, the study [0] used iPads (on maximum brightness).

Some releveant quotes:

"The randomized, crossover protocol design consisted of two conditions: (i) reading an LE-eBook (iPad; Apple Inc., Cupertino, CA) in otherwise very dim room light for ∼4 h before bedtime for five consecutive evenings, and (ii) reading printed books in the same very dim room light for ∼4 h before bedtime for five consecutive evenings."

"Third, in the present study, the LE-eBook was set to maximum brightness throughout the 4-h reading session, whereas, by comparison, the print-book condition consisted of reflected exposure to very dim light."

"Lastly, although the short-wavelength light from the LEeBook may have been responsible for the effects reported here, this study did not include a light-emitting device with longer wavelength for comparison, so our findings may be due to the difference in irradiance level rather than spectral composition."

[0] - https://www.pnas.org/doi/pdf/10.1073/pnas.1418490112

My eyes would bleed after looking at an iPad with maximum brightness for 4 hours.

What would be the point otherwise?

The study also didn't use a typical eBook reader - it used an iPad - set (as you say) to a high brightness level.

Yeah my kindle have perfectly fine backlight range for night reading.

But then you can't sell blue blocking products.

> “Is it the light, or is it the mental activity from the screen?” This study attempts to answer...

If that was the aim of the study, then it could be reasonable to max brightness vs paper to distinguish between light/brain activity.

Dimmable LEDs usually dim via PWM, which might in itself pose a problem for brain health. Best to buy bulbs that are dimmed out of the box.

I strongly advise against buying and using lanterns, they release a lot of toxic soot. Probably negating any health benefits you get from normalizing your melatonin levels by a large amount. Technology Connnections of YouTube made a series of in depth videos about lanterns, how they work, how they can spill and set you and your home ablaze and just how much soot they produce. Don't use them, unless you're outside camping. It's an inconspicuously dangerous technology that has more risks and downsides which will surprise you in very unhappy ways when it's used in inproper ways. Like using it for reading inside your home so you get tired more easily thus more careless in handling them. The use case for these is VERY narrow and you need to know what you are doing.

As much as I enjoyed the blog post, the tiny bit with the lanterns was stupid. I wish they had dug into the downsides of those with the same interest and rigor as they demystified white LEDs. That was such an oversight. Lanterns are more risky than white LEDs that leak blue light.

Yes, there are "clean burning" lanterns, but the innocent casual reader might just not buy the best type but some cheapo fuming, leaking one from Amazon. I think mentioning them is irresponsible especially after they've established themselves as someone who's an expert in blue light emitting LEDs (argument from false authority). But even with those clean burning lanterns I don't buy into how clean they are. There is no sootless lantern.

Agreed, there's a difference between looking skeptically at tech LEDs and recommending people go full Chuck McGill, and the author rides that line well until that point in the article.

I think what we need is to understand exactly how the spectra is different and use optical filters to get an exact match, assuming current high CRI and warm white lamps aren't enough.

We could even use a dichroic filter to send part of the blue peak back for another trip through the phosphor. We should probably be doing that already for a little more efficiency if that's a real idea and not nonsense I just made up.

I think there are multiple practical ways to mitigate this issue. Blue light filtering adhesive tape could be a viable solution in some cases. You can buy those UV filtering adhesive sheets for your window for protecting your precious light sensitive knick-knacks, but I don't know if they filter the spectrum between 450 and 480 nm though.

In other cases another helpful tool would be a portable light sprectrum analyser, with which you can simply weed out the bad lights before you buy them, or return them immediately after buying in case you can't test them before hand.

Then the blue light filtering function in devices is probably the most accessible self-defense mechanism for the average consumer in most cases.

Or just go to bed when the sun goes down or change your job/shift. Behavioral adjustments, they cost nothing except some brain energy.

As a last resort melatonin supplements come to mind. In combination with Vitamin D supplements for the winter time, they don't seem that bad. Even though I've heard that you will have trouble falling asleep if you stop taking melatonin.

Or perhaps... use incandescent lights! They still produce less CO2 than lanterns and they don't stink. Also they are almost as convenient as LEDs. And you can still get them from some sources.

The solution I would prefer is for manufacturers to just build safer products and speaking from experience government regulation is the only sure way to get the manufacturers to actually commit to it. Marketing wank doesn't work because people can't test it and there's too many factors that play into sleep quality and (decades later) cancer, so the manufacturers cannot be held responsible for the effect. They can only be held responsible if their products fail measurable tests, like how much blue light they actually emit.

There are also probably very personal and biological variables involved too that the post doesn't mention. I stare into monitors and phones all day long. Every light in the house is full-blown LED. I can't help but fall asleep at 20:00 in an led lit room watching led TVs, while my led phone drops onto the floor after I've fallen asleep. I've been in an extreme LED environment for over a decade and never have problems waking up at 6:30 and falling asleep in bed at 22:00. I totally agree with concern raised by the article, but I also think it lacks the whole picture of someone's lifestyle. People have struggled with sleep issues well before LEDs.

I've battled the opposite in the form of clinical, anxiety-driven insomnia my whole life. I've found it utterly debilitating at times and have quite literally struggled since birth, long before electronics and LEDs were common.

I can confidently say you're so right about the number (and type) of variables. Sleep hygiene as we say in the biz is a very complex and personal issue.

I've tried everything under the sun from strict routine, screen avoidance, both abstinence from and ample sex, more reading, less reading, zero caffeine, limited caffeine, ALL THE CAFFEINE, changes to diet, fasting, supplements, and even medication.

There are usually relatively minor, short lived improvements but it's only a matter of time before I'm spending my nights once again staring at the ceiling, mind at full-tilt.

Whenever sleep comes up in conversation, and I mention my struggles, I feel like invariably I'm met with a response along the lines of "you _just_ have to...", and "have you ever tried ...?" followed by some arbitrary rule or herbal remedy.

Since about the the introduction of the first iPad, consensus seems to have formed the root of all sleep evil is screentime.

Sleep (for some) is an incredibly sensitive and personal struggle. Alarmist "mankind is doomed!" make it even harder to understand the greater picture.

It's closely related to diet. There's always some fad trending, and a number of people who find success in choosing a "better" diet almost always have a system they'll fervently claim is The Way.

The science is relatively clear on light though. I just appear to be some form of mutant.

I sympathize, having suffered from bouts of insomnia for decades. I'm with you, in that none of the oft-cited 'cures' ever worked for me.

My most recent 'solution', which has been working better than most attempts, is reading. On my phone, because my eyes are old. Doesn't matter that it's a screen, lit by LEDs. All that matters is that it's not real life (no news, or anything along those lines). Fantasy fiction mostly for me. Gets my mind to quit spinning about real life issues, and after a little bit I can feel myself getting sleepy so I drop the phone.

I wish you nothing but the best of luck finding something that works for you. Few things are more irritating than routinely spending hours in the middle of the night staring up at a dark ceiling.

I can relate deeply to this. Spent the last 2 years trying to get treatment for what turned out to be a neurological sleep movement disorder with an insomnia component. Basically I have sometimes ~150 involuntary limb movements/hr during sleep, they sometimes wake me up but even if they don't I wake up exhausted.

Things are getting better with medication finally, but yeah I've learned not to bring my sleep issues up with people generally. I diet, exercise, avoid caffeine and alcohol yes I've tried magnesium, as well as a slew of atypical antipsychotics, very old tricyclic antidepressants, and a parkinson's medication. Most people have a very hard time imagining what it's like to fight for each hour of sleep, so have a difficult time empathizing I think

No matter what problem you have, you will always be met with the "just do this, it works for me". Eating disorder? Just eat. Can't sleep? Just do some running one hour before bedtime. The invisible disorders are much harder to get any sort of understanding for than the visible ones. If you use a wheelchair because you are missing limbs, noone will tell you to just get up and walk.

How did you get that diagnosed?

had a polysomnograph (aka sleep study) done which allowed them to recognize that I was having these movements during my sleep. My wife had always assumed I was just tossing and turning constantly while awake and I obviously had no clue what was going on without that PSG

This sounds naive perhaps but would velcro straps or other gentle arm restraints prevent movement and allow you to sleep better?

The first issue with that is periodic limb movements (or PLMs) by definition can actually range from subtle movements almost like muscle spasms to large limb movements, so constraints would be limited in efficacy for that purpose specifically. This would also surely negatively affect any insomnia, sucks enough waking up at 2am involuntary when I'm not in restraints

That said, my father has a sleep movement disorder as well- but his is more extreme and called REM Behavior Disorder. Basically means he physically acts out his nightmares on a regular basis. His neurologist has been trying to convince him to put barriers on the side of his bed so he doesn't fall out and injure himself but he's been hesitant. sucks getting older.

These don't actually prevent moving. Restraints simply mean the movement won't be large. Great solution to prevent damage if you hit things in your sleep or, say, you have had a stroke and can't control one arm. It just doesn't actually prevent the movement or the signals that make them (muscles will still get the signal to move).

> The science is relatively clear on light though.

AFIK since is clear on:

- a increase in blue intensity reducing melatonin production

- higher melatonin levels before sleep helping with falling asleep

- melatonin is an important factor when it comes to the regulation of the inner clock

but the exact degree to which led light will make it harder to sleep, especially if in combination with other sleep issues, is much less clear cut

For example melatonin doesn't make you sleep, it (simplified) puts your body in a state in which it's easier to fall asleep. While that might sound like it's the same on the first look it's quite a huge difference.

In a certain way you could say melatonin is a major way our body signals itself "now is a good time to sleep", making it somewhat easier to fall asleep.

But people do not need melatonin to fall asleep. Some people can (oversimplified) fall asleep whenever they want, some are conditioned to fall asleep under some specific trigger. In both cases this often works pretty much unrelated to melatonin.

In the other direction if you have some issues which bare you from sleeping, e.g. bouts of anxiety or somniphobia, then having more or less melatonin is unlikely to make it difference, you won't sleep either way (EDIT: until you are strongly sleep deprived, overcome the anxiety or take some sleeping pills).

Anyway reducing the intensity of light in the evening, especially blue light, and making sure you get a lot of light in the morning (i.e. sun light, because your indoor light bulbs are most likely much much less intense) is always a good idea, even if it (hypothetically) would not affect melatonin it still would help with creating healthy habits, and habits are powerful.

I've been a terrible sleeper for about a decade. Weeks on end where I am only sleeping a few hours a night. Can't fall asleep, can't stay asleep, just tired all the time. Tried all the sleep hygiene recommendations but made no difference.

Started supplementing with creatine and about a month later had the best sleep of my adult life.

Shortly after switching creatine brands, I noticed my restless legs were back and I couldn't get to sleep. Switched back to the first creatine brand and a couple weeks later and I am sleeping again.

I don't know if the creatine helps me sleep. I started taking it because I heard on a podcast that it can help prevent cognitive decline as I age. I also started breathing through my nose when I try to sleep so maybe that was what made the difference.

> A major negative is that marijuana is usually grown with heavy pesticide use (even the certified organic stuff) so unless you grow it yourself it isn't really healthy.

Is there a source for this?

I'd worry about what else is in the one that helps you sleep to cause there to be a difference.

Or perhaps there is something lacking in the brand that does not help them sleep? By that I mean maybe there is less creatine than claimed, or it is supplied in a form that is harder to digest.

Really hard to know, but the creatine that didn't seem to help was a cheaper, bulk buy. My guess is that it wasn't as much creatine as it said. Unfortunately, I feel like there is a lot of misrepresentation around supplements.

That is of course also an option, but a less scary one

Any chance there was potassium in the one that helped RLS? K is a common relief for it.

> Whenever sleep comes up in conversation, and I mention my struggles, I feel like invariably I'm met with a response along the lines of "you _just_ have to...", and "have you ever tried ...?" followed by some arbitrary rule or herbal remedy.

So I hate to be that guy, but did you look into an ADHD diagnoses?

ADHD medications help people with ADHD gain control over racing thoughts, and that allows them to sleep.

How is your breathing while sleeping? If you have sleep apnea you could have subconsciously associated sleeping with axfixiation.

This is the particular problem I have. A CPAP machine remedied the breathing, but it was very uncomfortable to wear, waking me up. Now I use nose strips (Breathe right) and a slightly inclined bed. I still snore but it seems to have improved my breathing. Next on the list: losing weight.

I'm interested in exploring a completely different type of bed design that would allow apnea sufferers to sleep securely with their head face down. Not just a mattress with a head cavity in it, but a design that would be both comfortable yet passively discourage subconsciously turning over in the middle of the night.

OK not to be that guy.. and please don't misunderstand, I assume that like you say you are just different and that individual variability plays a part and people can have sleep conditions.

But since you did not literally mention either thing, how much sun exposure do you get per day? And how much Vitamin D3 do you take during the day, and melatonin at night?

I have had the same experience, and am only listing what helped me because I have never seen it mentioned anywhere, and stumbled upon it myself after decades of trying everything:

For me, it seems to be the combination of 10,000 IU vitamin D before 10 am, and >120gr protein taken at evening. I am approx 85kg.

The protein is the more important component - it improves things considerably but not fully. For more than 20 years into adulthood, I was eating approx 50gr of protein per day (being vegetarian, you have to be deliberate to got more, and I wasn’t). Since this discovery, life has several times taken a path that for a while made deliberate meal planning a luxury, and every time my protein intake dropped, so did my ability to fall asleep at regular hours.

In defense of the layman people, they are not doctors, and they can't recommend prescription drugs.

And sometimes non-doctor solutions do help and complement official treatments.

I started mindfulness neditation a while ago and it did me wonders to help me sleep. At first by the act of meditating, and then by some byproducts on attention span and fleeting thoughts.

I relate very much to this. In particular the well intended but ignorant suggestions.. I think it's often hard for most people to truly appreciate a problem they don't have.

You sound like me (unfortunately).

Did you ever find anything that helped?

Not a solution that works or is available to everyone, but for me, small doses of marijuana taken just before bed has changed my world.

I’m currently traveling and in a state where that isn’t an option and I haven’t had more then 4 hours in each of the past few nights. Will be glad to get some rest tomorrow.

I (unfortunately) am sometimes exposed to second hand marijuana smoke (from other people in the building smoking) and it does seem like there might be some positive effect in my case (there are a bunch of different types and I have no idea which ones I've been exposed to). A major negative is that marijuana is usually grown with heavy pesticide use (even the certified organic stuff) so unless you grow it yourself it isn't really healthy. Of course, smoking anything is also not healthy but you don't need to smoke it (and shouldn't). Also, many things help with sleep short term but with long term use you go back to normal (except that often quitting makes things worse for a while).

I've also had bad insomnia most of my life (and a non-24 hour circadian rhythm starting somewhat over a decade later). Early on it seemed to be anxiety/racing thoughts related and what finally mostly prevented that part for me was meditation. I still occasionally stay awake due to racing thoughts but not often. Unfortunately, that didn't ultimately help with the insomnia, which got somewhat worse (or at least different) over time :(.

The meditation method I used goes like this:

1) In general, althernate between focusing your attention on your breath as it touches your skin above your mouth (since it does that all the time you can kind of feel it and not feel it at the same time) and either active or passive muscle relaxation (mostly active unless you are getting tired enough not to feel like it).

2) For active relaxation, tense muscles in one group a time (I doubt the exact organization matters, I think I used three or four groups: arms and hands, core muscles, legs, and possibly feet) for several seconds and then feel the contrasting relaxation for a while after you release them. For passive, just tell yourself you are relaxing those particular muscles and try to feel them relax.

3) The time split between focusing on your breath and relaxing muscles doesn't matter, if you are having trouble focusing on your breath then just switch to a relaxation cycle.

4) For getting to sleep, wandering thoughts are fine. What you want to avoid is strong emotional reactions to your thoughts, including a feedback loops such as where something feels like an excitingly good idea (when you are half asleep and not so good at evaluating what is a good idea) and that leads to other thoughts that feel like good ideas or building on the same idea. If you really thing something is a good idea get out of bed and write it down along with enough follow up throughts to find the same stream of thought the next day (should it prove interesting to do so, which is not usually the case in my experience). Otherwise go back to the relaxation/breath cycle when you notice you have a stronger emotional reaction to your thoughts. Other feedback loops include remembering past mistakes or bad events (which can either then go to moment by moment recall of one event or remind you of other similarish situations) and focusing on a difficult current situation (again either going into detail about the current situation or often recalling any memory connected to anyone or anything involved in the situation). It may (or may not) be helpful to think of it as a type of internal drug addiction and you are trying to recognize when drugs that keep you awake are released internally rather than noticing particular thoughts.

5) Visualization can make it easier get to sleep if you are able to do it, so you can try imagining yourself on a warm beach as you do the breath focus and relaxation. I can usually only do that when I am about to get to sleep, if I happen to think of it (and noticing I'm about to get to sleep can make it harder to actually get to sleep :( ). Also, make sure you are actually sufficiently warm (and not too warm if you can avoid it) since that can sometimes be surprisingly difficult to notice even if it is keeping you awake.

6) I didn't become a world class meditator over the decades I've had insomnia, I mostly just try to use it when I notice racing thoughts, which is not that often these days (infrequent enough to not always think of it when it does happen :( ). I think it was 5-10 years that I meditated frequently before racing thoughts were rarely an issue, although it was very quickly obvious that it was helping. I've lately been thinking that I should try it again more regularly to see if it could help some even without racing thoughts (however, I don't think the circadian issue is affected much if at all by the meditation).

Some people find a formal Cognative Behavioral Therapy course to be helpful (or reading books that cover the same techniques), however some of the techniques won't work at all if you have circadian issues (and could make the circadian issues worse).

I've had similar problems since I was a little kid.

I do try and combat the blue light problem with nightmode on all my screens, turning off LED light bulbs, and, as weird as it might be, donning my red LED headlamp to get through the evening without much blue light in my life.

>I just appear to be some form of mutant.

This may be literally true for me given that I grew up in ground zero for the DuPont C8 poisoning.

I mean the problem with many of the studies quoted and referred to in the article is that they are about correlation but fail to show causation outside of "that seems right if you approach it with a mind which has already been biased to believe it".

For example night work independent of light has _a lot_ of ways it can negatively affect people, cause stress and in turn increase the risk of cancer.

And while the relationship between melatonin and blue light does exist the magnitude of it's effect (compared to other factors) is much less clear and might vary hugely between people.

Especially when it comes to reasons why you sleep is bad there are docents non melatonin related problems of which the negative effect can by far outweigh any melatonin difference caused by blue light.

I'm also like this, very rarely do I have trouble falling asleep and usually it's because I can't stop thinking about something.

But I feel like it's really that I'm just that tired in the evenings, and feel like I always needed more sleep than the average person.

We'd need stats about the number of people reporting problems with falling asleep and quality of sleep over the decades I guess. This might very well just be something that manages to push people over the edge and thus makes a difference, just not for those of us who are at the more extreme ends of the spectrum.

Also even if it doesn't affect my sleep quality noticeably, I wonder about the cancer risk part; is that a direct result of worse sleep, or might that still affect me?

Age may be a factor. Falling asleep wasn't an issue when I was younger, but it did get tougher in middle age.

I can sleep in a sunny day outside at noon (lots of blue light around) like a baby! : )

(which was very handy living 5 years at the polar circle. the only off thing was discovering a ca 26 hours daily cycle of mine in a long stretch of solitary work and lots of food at home, when I did not have to sync my activities with any single human being for more than a week during a summer)

N = 1

There is always a time lag between the introduction of a cool new technology, and the discovery of its negative effects on human health.

DDT was invented in the 1940's, and it wasn't until twenty years later that people discovered its negative effects through bioaccumulation. Teflon was invented in the 1930's, and it again took decades to discover its negative effects on human health, apparently under high heat. Cigarettes: decades until we knew scientifically they were bad.

Just a couple days ago there was a thread on HN about low sperm counts, with a lot of hemming and hawing about whether or not the effect is real. Here we have a claim that LED affects sleep cycles and melatonin production. We know testosterone production is related to sleep quality. Are these two related? We also have observed early puberty in girls. It went up during the Covid pandemic, when screentime increased for all school age kids in America. Is there a link between early puberty, LED screens on computers, and dropping sperm counts and testosterone levels?

We don't know scientifically. Expect to find out in two decades, when its too late for you to do anything about it!

Artificial lighting has existed for hundreds, if not tens of thousands, of years. People used to breathe superfines and ultrafines from daily cooking fires in nearly indoor conditions. Hell, people living in cities next to highways have no idea how they're shortening their lives if they don't have extreme MERV air filtration like I do. The AQI inside right now hovers at ~5. Outside, it varies from 15 to 200. I've been where P1.0-P10 was 5000+, to where going outside required a P100 or N100 full face respirator because the shit snowing from the air stings your eyes.

Comparing an imagined concern to the life-destroying travesties of Agent Orange, Tetraethyl lead (leaded gasoline), tobacco, lead acetate, DDT, PCBs, vinyl chloride, heavy metal- and actinide-polluted water, and radium poisoning is unscientific, lacking in perspective, and offensive.

To avoid evidence and testable hypothesizes is to become a conspiracy theorist.

If you're worried, turn off the screen and get a sleep mask. Artificial light won't turn your DNA into paper dolls. If it did, we'd know by now.

> is unscientific, lacking in perspective, and offensive.

I agree it is unscientific speculation. Science doesn’t have any answers.

As one example, there are no conclusive scientific answers on why global male testosterone is declining, or why American girls are experiencing early puberty. Any plausible explanation has compelling reasons to dismiss it, and we can’t know scientifically if they are correct.

Yet we can see both clearly in the data. If you want to escape these changes, you can only get answers outside of scientific knowledge.

> offensive

There’s nothing offensive about these comparisons. When DDT was invented, we didn’t know it would bio accumulate. When iPhones were widely deployed 15 years ago, I doubt many predicted they cause sleep disruption, and potentially disrupt hormone regulation.

They are both cases of harms taking decades to show up in scientific knowledge.

> Yet we can see both clearly in the data. If you want to escape these changes, you can only get answers outside of scientific knowledge.

Those would be not answers, then.

This is a common misconception. I don't need science to tell me not eat dirt, my sense of smell does that just fine. I also don't need science to tell me why someone is being mean to me, I can judge the social situation and make a good guess.

Science is great and gives lots of really good answers, but there are lots and lots of other ways to get answer.

> Yet we can see both clearly in the data. If you want to escape these changes, you can only get answers outside of scientific knowledge

This is not an arena where preferences and guesses will remotely help.

LED and incandescent bulbs are artificial lighting like m&ms and avocado are food. Any incandescent bulb gives black body full spectrum, turn it down to get friendly fire-like yellow, and most LED (even visibly white) give a very spiky spectrum plus you choose between PWM or high brightness.

> Artificial lighting has existed for hundreds, if not tens of thousands, of years.

Yes, and the climate has always been changing too.

A large part of the post is about the exact reasons why this kind of artificial light is different.

I suspect that (some types of) plastics are going to be a big contributer to some of these problems. They contain a number of endocrine disrupting chemicals, and we're typing on them, mousing with them, steering our cars with them, walking on them (most carpet is plastic these days), wearing them, eating off them, drinking from them, washing outselves with them ...

But yeah, the time-lag is a real problem, and coupled with lack of regulation with these technologies and novel compounds that are often introduced into our lives with little or no testing. Very much a "better to seek forgiveness than seek permission" scenario, except in an irresponsible and reckless way that's focused on profit, not safety.

> They contain a number of endocrine disrupting chemicals …

Tangential, but I worry about the oleophobic materials used on touchscreen glass panels.

Anecdotal: even before the great oleophobic coatings we have now, a family member managed to be allergic to touch surfaces. That seemed to include both smartphones and laptop touchpads. Made her skin flake, obviously extremely disturbing when that happens on the tips of your most agile fingers.

Also keyboards, clothing and furniture.

For the first time in my life, I think I finally see the appeal of wooden keycaps.

Can finally justify that four figure keyboard build!

But not lubricated builds!

Stone, for that extra-clackety tone to my Model M!

Sealed with unknown resins

> We don't know scientifically. Expect to find out in two decades, when its too late for you to do anything about it!

The alternative is for humanity to introduce layers of bureaucracy and regulation for all new technology to prevent them from being used until it's been proven to be safe across decades of use. This is both impractical and inefficient (we might focus research on speculative tech nobody ends up caring about, new tech is often prohibitively expensive until it's mass produced, etc).

When we are using the entire world's population as a guinea pig, and the stakes can be as high as "we accidentally sterilized/killed/crippled a large part of the world's/our nation's population", I don't know that having a less sticky cooking pan now instead of 20 years from now is worth it. I agree that a ban on new untested inventions seems impractical at the same time. I don't know what the "right answer" is in this case, but maybe there should be more regulation on testing potentially dangerous chemicals a start.

Impractical from the standpoint of someone who's looking to profit off the invention surely, but explain why that should be the primary driver and not general wellbeing?

Fun fact: leaded fuel was known to be detrimental to health when introduced in 1924, but it was good for the bottom line so it was done anyway. It can still be said to follow the trend of introduction and then (much later) being discredited and remedied.

General rule I keep is the more restrained on new tech you can be the better.

Basically, I avoid most synthetic, gmo, store bought stuff where I can. That said, I have AC, heat, and will use meds when I need them (even real advanced ones). There’s always risks but my cast iron works great to cook with. No synthetic hormones for me, and limit phone use is allgood.

Do you also avoid animal products? Lotta hormones in those.

Raise my own / join a co-op.

You can get raw milk and any meat from the Amish where I’m at. Amazingly good.

I don’t think there’s such a lag to discover the negative effects. A couple of years perhaps, but not decades.

What you are pointing at is the time when these negative effects can’t be rejected by their respective industries. Teflon and cigarettes had the scientific experiments done pretty early, and from there it was the different companies fighting the results to affect public perception.

New products spreading successfully in our society always have a set of companies getting big and powerful, with a critical interest in killing any attempt to paint their products as nefarious or needing caution. Of course it will take decades to get them to acknowledge they’re screwing the whole population.

PS: of course any new technology is always a trade-off, and the risks can be worth the upsides. For Teflon, even knowing the issues, many people will still chose to use non-stick for sheer convenience. BTW it’s not just “high” temperatures (“high” meaning heating your pan too much for 2~5s from memory), you’ll get contamination on physical damage and wearing off of the coating as well.

Banning ddt has lead to the death of many millions of people


I think they are referring to the fact that it was used to eradicate malaria in a lot of places by destroying mosquitos and can't be used in that way now that it is banned.

Andrew Huberman of Huberman Lab podcast discusses this in the first 4-5 episodes of the podcast. The takeaway is: it's late-night bright light, rather than blue light, that has effects on the circadian rhythm. It's an appeal to authority but I think I'll go with the professor of neurobiology and opthalmology on this one.

(Post author here, huh, it hit HN...)

This is not consistent with the studies I've read. It's a "total lumineous flux in the 460-490nm range" concern. The deep reds, up past 600nm, don't seem to have any impact on melatonin, nor do violets below ~420nm - though they can have other impacts on the retina and such.

Bright light will, all other things being equal, be worse than dim light, but "dim blue light" is still really bad for melatonin levels and sleep.

Some of the older studies did find an impact up in the greens, but they were for fairly short duration exposures - 30 minutes or so. The impact of the longer wavelengths, over a longer term, seems to be muted by [mechanisms somewhere in the system], leaving the blues with the most impact.

You're welcome to trust Huberman, but I'd encourage you to read the papers yourself (I've read dozens and simply picked the most relevant here). There's quite a bit of work on this matter from the past 20-30 years, and they all seem to conclude that "blues matter." Greens and above don't have nearly the same impact, and they don't have the longer term impact. I'll also suggest being careful about conclusions drawn purely from the absorption spectrum of the molecules involved, as the body doesn't seem to react directly to them, but to some skewed version. Unit tests are nice, but end to end tests cover all the details in the process.

This is covered by Huberman. Our night vision is ~3x more sensitive to blue light than red, probably because starlight has more blue. Blue light is ~2.5 worse for keeping us up but would actually be better if turned it way down like the 3x implies we can.

At normal levels the 3x gets lost in the exponential to much light we get at night.

Since you seem super duper into this, you could try what I do on many evenings even just as an experiment. I just strap on a very nice LED headlamp that has a pure red LED that I use for "night mode".

That it uses way less power is actually just a side effect of me wanting all the blue lights off at night. I know it's not for everybody, but I find it really relaxing. The trick is to get one that's not a joke lamp from china with a fat markup but a nice headlamp with powerful LEDs. Like this: https://www.blackdiamondequipment.com/en_US/product/spot-400...

The relevant bit being: "Settings include proximity and distance modes, dimming, strobe, red LED night-vision and lock mode"

I also have a couple of 'hurricane' lanterns and I really enjoy the fire-based lighting but even with "clean" kerosene the smell can be unpleasant indoors.

Somewhat likewise I set my Hue lights to red or a dark orange at night; this seems to work well, at least for me.

There's even a home assistant blueprint that is quite nice for matching the external colour temperature for LED lights that support it, it's basically flux for your LED Lights.


This plus dimming plus red lights in the bedroom and flux for devices I have found works pretty well.

Nice, thanks!

Ooh the post author! I have a question. When I buy light bulbs they always list the color temperature but not the lumineous flux, what's the relationship?

I buy dim bulbs that have a temperature of 2700K for evening applications precisely because of this belief that brightness and color impacts sleep quality, am I right or is it just placebo? It seems to help...

"When I buy light bulbs they always list the color temperature but not the lumineous flux, what's the relationship?"

Hi! LED and LASER module design and manufacturing tech here!

There is a small correlation with LEDs and luminous flux - the ones with higher green peaks (2700K-~4000K CCT) will have a higher luminous flux at full power as green (~552nm) is where the lumen is weighted and those tend to have more output in that converted color range versus the cool white (which have a little less green and a bit more blue.) This really only applies to phosphor-converted LEDs, RGB combo LEDs are narrow-spectrum in emission, and you can't really describe them by luminous flux, rather photon flux or radiant flux per output channel, as the luminous flux will always be highest from the green LED, no matter what, due to the weighting of the lumen in the green wavelengths.

Temperature describes a distribution of wavelengths. Higher is bluer, lower is yellower. Both brightness and color matters. If you want to be as safe as possible, buy pure red LEDs for use 1-2 hours before bed and don't expose yourself to any non-red light. The difference is (no pun intended) night and day.

I think the temperature is describing, in a way, the dominant wavelength (think the peak of a normal-ish curve on the EM spectrum). A lightbulb that appears less blue will inevitably be emitting less blue. But that’s not to say it isn’t emitting across a broad swath of the spectrum and you’re still getting the wavelengths that are being argued as problematic to sleep. You’d need more data or tools to determine just how much of the “offending” wavelengths are making it into your peepers.

Anyways, hopefully a real expert chimes in. :)

Keyword to search is melanopic spectral efficiency.

I’m surprised to see him championed here. He pops up on my Twitter feed sometimes and as a scientist myself, he comes off as an absolute quack. Dr. Oz for millennials and zoomers that think they can fix everything with the right supplements, red light therapy, and daily affirmations, with very little real evidence behind it.

A good summary here-


Not sure I'd qualify my comment as 'championing'. I refer only to his podcast episodes where he discusses topics that one would reasonably expect a professor of neurobiology and opthalmology to have an expert opinion on. It would seem ill-advised to accept as fact his opinions on things like fitness supplements, psychology, or anything else outside his wheelhouse, and while he may be producing content on that now, it seems largely irrelevant to me here.

I don't agree with that assessment at all. I have listened to several hours of his episodes and he discusses supplements, but rarely have I heard him actually recommend any supplement particularly strongly, except maybe Magnesium Threonate if you want to take Magnesium, but that's hardly quack level supplementation.

The impression that I get is that he discusses supplements because the audience wants to know about supplements, and because he experiments with them himself, but I've gotten several excellent and useful pieces of information about diet and sleep regulation and they all involved zero supplements.

Comparing him to Dr Oz is wildly inaccurate, even based on the top comment on the Reddit link you posted (which I still think is inaccurate).

He also did an interview with a person from the NIMH who personally only uses candle light past dark. It makes sense when you think about it.

Also apparently overhead lights are worse- the angle makes a difference.

(Post author)

Yes, there's an angle component that's a bit concerning as well. It seems that our eyes mostly respond to the blues "above the horizon" - which makes sense given how our world works. Blue on the ground isn't interesting, nor bright, and our bodies don't tend to waste energy building things where they're not useful.

It does imply that our overhead lighting (most homes have overhead lighting in some forms or another) is more concerning than we've broadly considered - screens in the line of sight are important if bright, but the overhead lighting is hitting more of the relevant cells.

Candles also supposedly awful for PM 2.5

They are. Any sort of "open flame burner" is likely to emit an awful lot of PM 2.5.

However, most of the lanterns (think your standard "hurricane lantern" or "cold blast lantern") are quite clean burning. I've been using lanterns for a while now, and I have the equipment to measure PM2.5 and PM10 (post author here, you can find reviews of my lanterns and my particulate sensors elsewhere on my blog).

The lanterns are "basically zero" in terms of PM2.5 and PM10 in the exhaust stream, and when you dig into papers talking about kerosene lighting and particulates, they come to the same conclusions - most of the particulate is from the open flame kerosene burners, not the actual lanterns.

I use lanterns in my office in the winter for some extra heat (I'm the "solar shed" guy, winter sucks during inversions), and I see a fairly rapid rise in CO2 levels (about like another 2-3 people in my space), but I don't see high PM2.5 unless I've got an actual open flame candle going.

How about the fake candles?

I went through a period where as soon as I got home and out of the shower I’d go dark. I had a battery powered lamp that I used exclusively. I’d wear an eye mask with something to listen to playing. It definitely helped. I can definitely feel blue light waking me up much more easily than red. (Worked swing shift until midnight at that point.)

Isn't a fake candle just a normal light in a pretty container?

What about pilot lights on a stove/oven? I have an old-school unit in my house that has three pilot lights that are always on... the put off a fair bit of heat. I don't love the idea of them burning constantly from an energy standpoint, but I didn't consider the health effects...

Not nearly as bad as a candle, so long as the flame is burning blue.

Probably quite bad unfortunately. Look into NO2 exposure from stoves.

also increased co2 in closed environment is bad too

Candles produce soot which has much more significant data to indicate that it is detrimental to your health.

Blue light(instead of just lumens) has much less evidence.

It makes more sense to use pure red LEDs if you check the melanopic spectral function, where you see red has practically no effect. It's also less likely to emit PM2.5, CO2, or start a house fire.

Indeed, even after reading several of the studies cited here and elsewhere, this whole idea of blue light > specialized photoreceptors > melatonin production > sleep (not to mention cancer) seems like just correlations stacked on top of each other.

I understand that some people have problems sleeping, but saying blue wavelengths are a general hazard to sleep (not to mention cancer) is absurd.

What's your problem with the links in that chain? We know (or, at least, papers argue...) that all of the linkages are true, and I (post author) link some studies that look at the end-to-end results - blue light vs sleep. With what I consider to be fairly straightforward results.

I write having spent the last few months testing exactly this sort of thing in my life. Nights spent with LED lighting, or LED lit screens, I take a long time to fall asleep. Nights spent on incandescent lighting (lanterns or bulbs), I fall asleep quickly. It matches the results of the papers I've linked, and I'm pretty sure "Reading a book on paper by lantern light" vs "reading the same book on Kobo by frontlight" is the same mental activity.

> "Reading a book on paper by lantern light" vs "reading the same book on Kobo by frontlight" is the same mental activity.

How many times brighter was the light emitted from the ebook compared to plain paper?

We know that not getting sleep is bad, we know that bright lights affect sleep.

For this study to be convincing we'd need a number of things:

1) more than 12 people to take part.

2) Spectra controlled but the same overall lux level in the room. Both booth and ebook emitting/reflecting the same number of lumens.

Yeah those were good episodes, the key takeaway for me was early morning and late everning light, low angle in the sky, the "netflix innoculation".

BTW you're allowed to appeal to authority. The problem is "Appeal to false authority" which means listening to a UFC commentator about vaccination.

Denialists use the term "appeal to authority" when they want to stop you from citing any source, no matter how relevant, to refute their baseless opinions. It's obvious that we must appeal to authority sometimes, because otherwise specialisation couldn't exist and we'd all be back to sewing our own trousers.

IKEA sell a Tradfri bulb (304.413.80 in Europe) which has a 2200K colour temperature and 250 lumens output, which I've been using as a bedside lamp for the past year. At the brightest setting it is more than enough to read a book (usually we use it at around 50%), and it dims enough that we use it as a night light for kids.

The new EU light labelling requires a spectrum to be posted online. This bulb still has a blue peak, but it is mainly red:


The bulb dims well without flickering, but my only complaint is it doesn't dim that much. This seems to be the case with all ZigBee bulbs I've tried. A Philips Warmglow with a separate dimmer can be dimmer smoothly from off. Does anyone know why ZigBee bulbs don't do the same?

There are a number of factors involved in LED lighting quality, and annoyingly not all are tested for in reviews or shown on specs.

Think of an LED as a capacitor designed to leak electricity that emits light whenever it leaks in one particular direction. It's a bit handwavy but it works here. Depending on the design it might require more or less charge or voltage before the electrons jump over the diode (the light-emitting leaking step), and those characteristics affect how it behaves under different inputs.

One really common thing that affects the quality is the AC/DC conversion is handled. LEDs are DC. A common cheap solution is to use a half-wave rectifier, meaning half of the time the LED is "off". Technically it's more like "half of the time there is no charge build-up so the electrons won't always jump over the LED and the amount of on/off time varies based on specifics" (again, being a bit hand-wavy).

The result is mostly the same: with a HWR the LED isn't always emitting light. Normally these flicker too fast to directly see the flickering itself when looking at the lamp, due to afterimages (the frequency depends on the frequency of the AC input, so typically 50-60 Hz). But you can see it when looking at anything illuminated by the lighting and it drives me absolutely bonkers because it increases my eye-strain.

Example: with solutions that don't throw away half of the AC input waving your hands will result in smooth "motion blur", and with a HWR you'll see a stroboscopic effect. Another common example is cheap Christmas lights: if you move your eyes quickly they'll look like dashed lines, not smooth ones.

Now I hope that no dimmable LEDs use HWRs, because dimming will amplify the relative time the light is off. That will make the flickering worse. But we can't tell ahead of time because reviewers don't test for it! In fact, since there are no specs we can't even tell if any brand changes things between production batches. So I honestly can't say if this applies to Philips or Zigbee.

Regarding flickering of lights supposedly Dogs and perhaps other animals are quite sensitive to them.

I'm not surprised, many animals used to freak out at the flickering of old-school CRTs too

That bulb has a poor CRI though. Probably not very important for reading I guess.

There's a lot of talk about bright light, but for me it seems like there is actually something else at play that's worse.

For me, it's the incessant stimulation from social media, youtube, internet, etc that keeps me awake. It's this "just want more" loop in the brain. If I just read a book the last hour when I want to fall asleep, then I usually do, while if I would stay on a loop with the computer or phone then I can't sleep.

If something is sufficiently stimulating (like an unfinished programming problem or playing factorio can be), it can somehow put my brain in a high gear where it refuses to calm down for hours, so these two hobbies are very detrimental to sleep as well.

I hope I'm not exaggerating: it seems like this focus on light could be useful, but in a way it is a distraction from some even bigger problems. If only it was as easy as toggling for dim light!

actually, there are visual receptors in the eye which are directly tied to the hormonal center of the brain. Red/Infrared light is stimulating Melatonin and blue/bright light triggers Cortisol production.

Arguably, this is linked to the circle of the sun and a lifestyle that is heavily bound to sunlight.

I am a big fan of LEDs but the strobe effect is maddening and it only gets worse as they are dimmed. AC power crosses zero volts with every cycle so you need a driver circuit that can compensate. Most don't do a good job and I have replaced bulbs and dimmers multiple times to come up with something acceptable.

At the family camp, I retired my kerosene and propane mantle lamps in favor of solar battery powered LEDs many years ago. It was a matter of safety and convenience at the time, especially with children everywhere. The LEDs are powered directly from DC and I have no problem at all with them.



Interesting comment. I have a number of MR16 bulbs in my house that were previously halogen and are now mostly LED. They are a near constant source of frustration with bulbs burning out way too soon, some with what seems like wiring issues, a mix of incompatible switches, etc.

Curious to hear what acceptable solution you derived?


Good dimmable LED bulbs from quality manufacturers like Philips dim very well with many incandescent (leading edge) dimmers. Usually these bulbs are larger and have space in the base for a driver circuit that derives a brightness signal from the waveform rather than passing through the chopped current.

Smaller bulbs with no built-in driver are much more suited to dimming using a trailing edge dimmer or dedicated LED driver. These strobe like mad on a traditional dimmer switch but may benefit from having a single incandescent bulb on the same circuit to round off the waveform a bit.

For one difficult circuit I put a 5w ceramic resistor in parallel with the lighting to smooth out the dimming response between two different fixtures.

Are they low-voltage lamps? (usually have a GU5.3 base). If they are powered by old transformers intended for halogen lamps it might be worth changing the transformers to ones meant for LEDs.

Incidentally if there are dimmer switches in the circuits then those might have to be changed too.

Yea, 5.3 base.

Any thoughts on how to check the transformers? Is it as annoying as I assume because the transformer is hiding somewhere in the ceiling?

I've otherwise tried switch changes, but as you point out with the transformer, it might be that more than one component needs a change.

And maybe it's worth changing everything back to halogen!?

Interesting article - but I'm left to wonder how it applies to where I live - we have a two month polar day in summer - but AFAIK no increased incidence of cancer. Some people certainly struggle with polar day (and night in winter) - but 10 000 plus years of human habitation seem to indicate white nights aren't such a big deal?

There's a lot of research going on effects in humans - but admittedly I'm not really up to date.

I do recall this one that's tangentially releated:

"A circadian clock is not required in an arctic mammal" https://pubmed.ncbi.nlm.nih.gov/20226667/

Comparison of sub-$20 LED Light Bulbs with low Kelvin, 90+ CRI and low flicker, https://gembared.com/blogs/musings/the-best-daytime-white-li...

Thanks, I'll order some of those and put them through my spectrometer!

If you're willing, it would also be interesting to hear how the Bedtime Bulb from a past Show HN fares: https://news.ycombinator.com/item?id=18011075

Do you know how to order one without Amazon? I'm... rather opposed to them. In every possible way one could consider.

I would love to poke with one, but if the only way to buy one is through Amazon, I'm quite unlikely to actually obtain one. I genuinely don't care if I have to pay a bit more, I hate what Amazon has done to retail.

Hi there, if you're interested, you can pick one up from here: https://shop.bedtimebulb.com/products/restful-bedtime-bulb

Thanks! Greg, Bedtime Bulb founder

I'm using Philips Hue color LED bulbs in all our bedrooms, the hallway outside them, and the toilet. Since it can switch to using red+green LEDs in color mode, if you configure them with orange light dimmed to low/minimum at night, there should be essentially zero blue light. Works really well.

With smart LED bulbs you can also set them up on a schedule to light up the room very brightly in the morning and have motion sensors to turn on the light elsewhere, which is also very important for health.

Even though we've done this, I'm a bit skeptical of how terrible blue light is supposed to be. Just dim your lights lower and you should get most of the benefits. The natural light outside at night is quite blue, so I don't think it's blue light in itself that's the problem.. it's how much light there is in general and the body is just using the blue light to measure the general light level.

He's complaining about real-world LED bulb lifetime, but I've never had any of them fail on me for 8+ years, except for some specific IKEA Trådfri GU10 bulbs that had bad thermal design which they've obviously fixed, and they were replaced free of charge no question asked. It may depend on the quality of power where you live though.

This is why OLED lights is the future: http://www.ioledlight.com/ and https://www.oledworks.com/

I have been following OLED lights for a while and they seem to have fizzled out from a consumer perspective. Unfortunate as I would love to install them in my house.

Doesn't OLED tech (in TVs, screens) also works by having a blue emitter with filters for white/ colors (which is what the article covers) ?

This is different. Those OLEDs are transparent, only have one emitter.

Just the QD-OLED I think.

Those “color vision correcting” glasses (e.g. EnChroma) use an optical technology called notch filtering:

“EnChroma glasses are spectral notch filters that remove light from two regions of the visible spectrum: from the region near 480 to 490 nm (in the blue–green part of the spectrum) and from the region near 580 to 590 nm (in the orange–yellow part of the spectrum).” https://www.practiceupdate.com/content/the-effects-of-enchro...

This article states the conclusion of the research is the problematic light has “a peak around 477nm, with the 50% sensitivity level from 438-493nm”, and from looking at the graph it seems 420-500nm covers it down to 20% sensitivity.

It seems like a set of glasses with a spectral notch filter blocking out that chunk of the wavelength spectrum could do an end-run around all these issues. Put them on when the sun goes down and it doesn’t matter if your LEDs are leaking blue light, your dimmers don’t go low enough, or you can’t stop yourself going on your phone in bed. From other comments here it seems “light from above” has a particular importance for physiological reasons, so the glasses should incorporate a shroud from the top of the frame to your eyebrows to block out all light from above as well.

I’m no expert on optics but it seems spectral filters aren’t hard to buy. Something with a center wavelength of 475nm and a full-width half-max between 60nm and 100nm should do the trick.

I did some digging and notch/bandpass filters are on the expensive side, but you can buy sheets of lowpass filters for a reasonable price:


I would just form a cylindrical lampshade out of such a sheet and call it a day.

My bedroom has a dimmable, multi-colored LED in a cloth lampshade that definitely filters some blue light and it's possible to sleep with it on, so I guess the inexpensive, low-tech solution, as it's often the case, works just as well.

Yeah, it looks like off-the-shelf spectral notch filters are aimed at laser laboratories. Around 800 usd per lens so 1600 for my glasses, bit steep. You’d get some pretty awesome looking Doc Ock style goggles out of it, though

One can buy LEDs (actual LEDs as opposed to light bulbs with LEDs in them) without a blue peak. For example:


Digikey carries them, and they’re not terribly expensive. They’re a bit less efficient than the normal 90 CRI versions.

One downside: you get to build your own light fixture! But it will be a really nice one. :)

The council replaced the warm halogen bulb streetlights in our area with extremely bright LEDs that have no shielding towards houses. I slept in a ground floor bedroom with a bay window directly beneath such a light for a year. Despite installing blackout blinds as best I could, the ambient light in my room was about the same level as mid-dawn the entire time. My mental health suffered intensely almost to the point of psychosis.

LED lighting should be tightly regulated. At the moment they just appear to be getting brighter and brighter and more prevalent. I absolutely despise them.

It sometimes helps to call the council about this. Many streetlamps have the option for shading in certain directions to prevent your problem, but the guys installing it might not set it correctly.

My parents had the exact problem. Called up the city and actually a few days later a cherry picker appeared and there was no more light glaring into their windows.

> cherry picker appeared

Oh, so that's what those things are called :-))

Don’t sleep on eyemasks. Get one that is domed for the eyes.

One thing I haven’t seen mentioned is all the supplementation with melatonin people are doing. Does ingested melatonin still have the same protective effects?

I've not looked into it that much (yet).

Short answer, from my view, is that if we've screwed up lighting enough that we need supplements, the easier option is to fix lighting.

I was thinking about this too, and I'm not sure I agree. Last year I replaced the last of the incandescent lighting in my house with LED. Most of the LED blubs I've bought are 2700K, but it sounds like from what your blog post says, they may still have too much blue light in them?

The savings on my utility bill were immediate and more significant than I expected, and the bulbs themselves were not cheap. So I'm a bit hesitant to switch back.

I've already taken melatonin supplements on and off for years with positive results: I've had sleep issues since I was a kid, definitely before I was in front of LED-lit screens all the time, and well before home LED lighting was a thing.

I may be suffering from some sort of sunk-cost fallacy, but especially given that I've always had (probably non-light-related) sleep issues, it feels "simpler" to just leave my lighting as is, and take some melatonin a few hours before bed. Obviously I'd prefer LED lighting that has better spectrum emissions, but as you note elsewhere, that product would be significantly more expensive. I do agree with you that it seems perverse to break ourselves with our technology and rely on supplements to fix it, but I think wholesale going back to incandescent lighting just isn't going to fly from an energy policy perspective. And I don't think burning fossil fuels in our home (kerosene lanterns) is a great idea; that's just trading one health problem for another.

I think at this point our realistic choices are: a) finding a way to make efficient, cheap "white" LEDs that don't blast out blue light, or b) some new yet-to-be-invented technology that has similar power consumption as LEDs, but healthier emission spectra. I just don't see incandescent lighting (or kerosene lanterns) as serious, realistic contenders for the future.

Edit: it seems OLED is actually quite a bit better when it comes to blue light emissions? (https://www.oledworks.com/news/blog/the-hazards-of-blue-ligh...) I wonder what is holding OLED back from consumer lighting. Perhaps cost?

I hope so - I've had chronic insomnia my whole life (and a fair mix of night terrors and sleep walking when younger). Without melatonin supplements I would not have any kind of regular sleep schedule at all. Although on the bright side, screens don't make it any worse.

I was also surprised to not see this discussed in the article. Melatonin supplementation seems like the obvious solution given how cheap and easily available it is. It can also go hand-in-hand with interventions the author suggests like f.lux or using dimmer lights.

Lots of good discussion and links to studies about efficacy here: https://gwern.net/melatonin tl;dr - yes it works and is much easier/cheaper than other things

Since this topic is related to the circadian rhythm, here’s my understanding of optimizing that (aside from lighting):

- No coffee 6-8h before sleeping. I try to keep it to before noon. Having a strong coffee at 3PM often means I stay up til 2AM.

- Digestion should be done-ish before sleeping. A rule of thumb seems to be not eating no heavy meals past 3PM. Or at least 6PM. For me, a big amount of protein for breakfast helps keeping hunger in the evening down. (You can find great discussions and small studies if you search for „eTRF“ on Reddit)

- Breakfast resets the circadian clock. Some people can’t eat before 10AM which is probably ok. I‘ve found that I can train myself to eat earlier, it’s a process.

- A bit out there - Creatine has been found to help sleep deprived people - not sure why that is, but I‘ve been testing this lately. Maybe it helps with circadian rhythm, maybe not.

- More about sleep than CR: An air filter near the bed improved my sleep quality by so much. I got a big one from Coway but it probably doesn’t matter much which one.

The ebook reader part is a bit weird since the paper doesn't state which model they used.

Many readers these days have warm LED lights. IIRC the Kindle Oasis can even adapt the temperature of the light.

Kobo readers have adjustable light temperature as well. I think their entire lineup, barring the one cheapest model, has that now.


It does state that it's an iPad (!) - see the Materials and Methods section, specifically page 1235.

Lol that's not an ebook reader

For the "just take melatonin" crowd: some of us can't. Its contraindicated for high blood pressure. and, for some people causes florid dreams (not always welcome) and "restless legs"

Is "florid dreams" a thing (Google didn't come up with anything meaningful)? Did you mean lucid dreams (though for the life of me, I can't understand why that wouldn't be welcomed).

I don't know the term either, but I experience what the parent poster said. I've tried melatonin, and it gives me crazy vivid dreams that keep up the feeling of stress. It doesn't rest the brain, it's more like being knocked out by concussion, and it takes hours to reset and wake up and get back to functioning.

No, it's not a thing, its a term my partner used. Lucid dreams you have (within limits) control over the narrative, florid dreams she described as hyper-real, disturbing and unwelcome.

"vivid dream melatonin" had heaps of hits. "melatonin nightmares" might be another way of putting it.

Happens for me. Not lucid. Never thought about it but florid seems like a good word for it (I'd guess at adjectives like vivid, emotional, confusing)

I have had led lights for over a decade. Come 10:30pm every night I'm falling asleep with no problem.

> Come 10:30pm every night I'm falling asleep with no problem.

I'd have said N=1 vs the study out there, but I too work with screens & LED lighting all the time & the "light spectrum" that affects me is not exactly the indoor component.

My personal theory is that the daytime to nightime being about the same lighting is what sucks. When the total range of lighting varies a lot, I don't feel as bad. A lot of my troubles have gone away with a sun room in my house, where I can get bright light without being exactly outdoor.

You might just have enough contrast in your day/night lighting for it to not matter to your perception.

Unlike a lot of the people who are either indoors all the time or just switch from an LED lit office to an LED lit living room after work.

Improving those with a proper sunlamp might be a good way around it, but they're expensive & sometimes feels like overkill.

>I'd have said N=1 vs the study out there, but I too work with screens & LED lighting all the time & the "light spectrum" that affects me is not exactly the indoor component.

Yeah my anecdote proves nothing. But for what ever reason they don't seem to impact my sleep. Just throwing my data point out there.

Also my wife hates the sharp white light so we always go for the warm yellow LEDs.

I’ve spent protracted periods of time with pretty consistent lighting all day and never had trouble sleeping. LEDs seem to have no effect on me, and I’ve slept till noon outside with bright Caribbean sun shining on my face. I know a lot of people like that.

My theory is that being obsessed with sleeping makes it hard to come by. Good luck applying that though.

I have found if I work hard, exercise my mind and body, I can fall asleep in about seven minutes and sleep for a solid six.

I go to bed at Ten. Up at 4:30am. My sleep score averages 81.

Yeah, for me exercise is always the key. When you exhaust your body with strength training and cardio, you can sleep in any environment, and it's good for you.

I find that nighttime alertness is artificially (and undesirably) propped up by having the sum total of the world's knowledge at my fingertips. The LED brightness exacerbates. I haven't RCT'd tbis, but my best guess is that excessive nighttime alertness is 2/3 due to content availability, 1/3 screen (and perhaps ambient) brightness. I take active steps to have both passively cut off after a certain time.

Great point, I feel often the same. The brain so often goes into a mode of "ah yeah, now is the time to google that one thing I was wondering earlier today", or "I just want to confirm this one small detail about thing X", and then my phone is pointed straight into the eyeballs again.

For those of you who have an iPhone, a handy feature that helps with phone lighting at night is "Reduce White Point" in accessibility features. It is different than night mode and reducing luminosity to the minimim and I find it's a nice addition. You can put it in the control center for fast enable/disable should you need it. I have trouble sleeping and I found this helped, albeit marginally.

I had sleep problems that I recently fixed. Nothing to do with lights it turned out but everything to do with feathers. To my knowledge I've never been allergic to anything before but somehow an allergy to feathers crept into my life. Pillow and duvet, both feathered and were killing my sleep.

Synthetic stuffing for the pillow and hypoallergenic wool for the duvet and my sleep life is much better. Might be worth a try.

I'm curious if some of the downsides of evening blue light could be mitigated with an increase in daytime blue light. It's all about the rhythm, right?

I work from home and got one of these monsters [1] to have on in my office during the day to help avoid the winter / darker time slump, and I think it's helped. I only run it during daytime working hours, in my office.

I avoid staring at my phone around bedtime and my sleep patterns are fine--I'd just hate to shift away from LEDs. I'm careful about choosing virtually only "warm white" ones, though as the article notes, that's not as bulletproof as I originally thought. Is the increased blue light spectrum fundamental to LEDs? Or something we could potentially solve with a film or filter (at manufacturing time or later)?

[1] https://www.amazon.com/gp/product/B08DY1GCC6/

What's the scientific opinion on blue blockers for prescription eyeglasses? There are some claims that suggest the health benefits are over stated. But my optometrist continues to recommend them given my profession and exposure to blue light.

Anecdotally, it appears it has helped but not sure if it's related to other factors.

I think it's been debunked and they provide no benefit. Check out https://youtu.be/NkJY9bgLyBE. That includes interviews with and MD who's high up in the American Academy of Opthalmology. At one point it's pointed out that you get orders of magnitude more blue light from the sky than any screen and humans have been encountering the sky forever.

I saw a study which said you can get the same effect by using clear glass and telling people it absorbs the important wavelengths. Also that blue light deprivation leads to depression in animal models. These kinds of things are hard to double blind for obvious reasons, but ruling out psychosomatic causes is really difficult.

For reading at night, I got an "amber book light" @1800K that basically looks like a 5" clip that you stick on the book. You charge it with a USB connector on one end that's hidden under a cap, and it claims to emit no blue light (though I don't have a spectrometer to test this claim).

The warm light makes reading a true pleasure and doesn't light up the whole room, just the book, which is much appreciated by my partner, who usually falls asleep before me.

I find I get sleepy faster than before with this thing. Of course, that means I read a bit less.

Best $10 I ever spent.


Recently I got two tips for working against this kind of problems in the evening: - melatonin spray - staring into a candle for some time

Thoughts? Subjectively speaking both seemed to make me more sleepy, but I don't know about the scientific background.

I don't mean to sound like a grump. I was taught this back in highschool in my 2010 psychology class.

How is this different from the long standing understanding we already had that blue light inhibits melatonin?

This isn't some groundbreaking new development. Blue light therapy has been around for over a decade to help people correct their circadian rhythms.

It's why the Kindle claims that it shines a warm light across the screen rather than directly at you. It's why mobile phones have begun to incorporate a night mode that can warm the backlight on the screen from a blue white light to warmer oranges.

Several things the article claims, which I was unaware of: The content of blue wavelengths in seemingly "white" LEDs; the content of blue light even in 'warm' LEDs (more minor but still present vs incandescent); and the impact of light position relative to the "horizon".

I'm still surprised these natural daylight lamps aren't widely commercialized yet https://youtu.be/aJ4TJ4-kkDw

The author should really rethink the idea of using kerosene lamps in his home. They produce tons of particulate matter, so you're trading one potential cancer risk with another confirmed cancer risk.

The ebook reader part is kind of disturbing, I have a warm mode on mine that I always use, and the brightness set as low as it'll go (I find it too bright, but they seem to use a linear scale so there's not much range of adjustment).

I have a red LED striplight above my bed for reading paper books so I will try using that for the ebook reader and see if I notice a difference. My main issue is that interesting ebooks keep me awake longer than interesting paper books, I have a "no screens after 8pm" rule but wasn't counting the ebook reader as a screen.

I recommend you to re-read the e-reader part but paying special attention to the scales of the graphs. They are all different.

Kobo Aura peaks at 4000 counts in the blue spectrum, while the incandescent also emits about 4000 counts. The Kobo Clara only emits 2500 counts when full warm.

The key thing IMO is that the paper book was 0.9 lux but they cranked the ebook up to 30 lux. I missed that the first time. They also had the ebook set to "harsh blue", which my ebook reader can do but it also has a "warm" setting as well as the obvious ability to turn the brightness down from "glare of a thousand suns" to "candlelight"

The "eBook" study should be treated with caution, since it was conducted using an iPad, not a typical eBook reader like a Kobo or a Kindle.

If you are using all red then it shouldn't be the light affecting you, only the content and the interactiveness that ereader provides.

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