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Member Forum >> Cureality Diet General Discussion >> Blue Light at Night Circadian Hazard
 Blue Light at Night Circadian Hazard
Bob Niland

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Posted: 12/28/2014 6:57:13 PM
Edited: 12/3/2017 4:11:29 PM (23)
 
Blue Light at Night Circadian Hazard

Blue Light at Night Circadian Hazard

Edition: 2017-12-03

Undoctored (page 305), on the topic of sleep, advises in an inset:
“If possible, it is helpful to avoid electronic screens for at least 1 hour before bedtime. The screens of modern smartphones, tablets, computers, and TVs are dominated by light in the blue wavelength, which can ‘reset’ human circadian rhythm, causing your brain to act as if it were bright daylight even late at night…”

Here’s more detail on this issue. We have yet another growing post-1980 era problem with a significant adverse health effect: artificial light at night, with a substantially increased intensity at blue wavelengths that suppress melatonin production. This blue light at night hazard, by the way, is entirely distinct from eye damage caused by the “blue light hazard”.

All of the following info is on the web in various places, but I wasn’t able to find any single page that pulled it all together. This paper, however, is a great overview of the problem, and has a long list of cites:
JBCPP: Artificial light-at-night — a novel lifestyle risk factor for metabolic disorder and cancer morbidity

This blue light at night phenomenon is a measurable effect. How significant is it? If you have trouble sleeping, or sleep poorly, and/or get sleepy during the day despite a low carb diet, you already know. NASA is taking it seriously: Solid State Lighting Module, SDTO 15008U (SSLM)

Don’t think you’re affected?
Consider this: despite having equal exposure to carcinogens and toxic diets, blind women have one half the breast cancer rate of sighted women. Now why would that be?

Light makes you/keeps you fat?
Yup.
Calories Proper: Artificial light regulates fat mass: no bueno.
In this study, adding 4 hours to the usual 12 hours of light slammed the autonomic nervous system, disrupting sympathetic input into brown adipose leading to a significant increase in body fat
despite not eating more or moving less.”

2016 report in Bipolar Disorders: Blue-blocking glasses as additive treatment for mania: a randomized placebo-controlled trial. Material improvements were achieved.

This is a physiological response, and there probably are no exceptions for genotype, age or gender. You, the reader, are affected.

Anyone who is tweaking their diet to get more antioxidants (just to mention one trendy fad), but doing nothing about circadian rhythm, is fooling themselves on reducing the risks of cancer and other ailments.

TL;DR?
Where this ends up at is that you actually need to do at least one of the following:
Plan A: get blue blockers and use them (trivial), or
Plan B: control all your light sources at night (surprisingly non-trivial), or
Plan C: take melatonin (tricky), or
Plan D: revert to a total paleo lifestyle

Humans are adapted primarily to a sunlight cycle that is red-ish at sunrise, blue sky most of the day (weather permitting), red-ish at sundown, then dark, with a night sky containing very low average light levels, and no peaks in the blue. Both the direct mid-day sun, and the sky itself (the “north light”) have a peak in the blue at wavelengths around 470nm. We respond to this light cycle.

There are genetic variations which affect light sensitivity. Those who are CC or CT for SNP rs1079610 may have heightened sensitivity at normal indoor lighting levels. That SNP may only show up in V3 Chip raw data.

What’s the mechanism?
Your eye has receptors other than rods and cones - called “intrinsically photosensitive retinal ganglion cells” (ipRGCs). They contain melanopsin, a photopigment with a sensitivity peak in the 460 to 484nm range (blue, matching skylight almost exactly).

This is a recent [re]discovery (circa 1990s, with data back to the 1920s). One thing these ipRGCs do is tell the pineal gland to suppress secretion of melatonin. Low melatonin results in delayed or poor sleep, plus other health hazards still being tallied.

Humans are adapted to some amount of light at night. Prehistorically, this was limited to starlight and a monthly lunar cycle. Although reported to be the same spectral power distribution (SPD) as sunlight, at a substantially reduced intensity, the one SPD plot I found for starlight and moonlight was relatively flat down into the blues (no blue peak).

We are more recently presumably somewhat adapted to thousands of years of firelight, which is yellowish and usually contains little or no blue light.

Later domestic lighting remained low-threat: candles, gaslights and the ubiquitous, but now “environmentally incorrect” Edison tungsten filament incandescent light bulbs. These produce little blue. The common amber high pressure sodium street lights are also seriously non-blue (but they are being replaced by LEDs which, so far, are not so harmless).

Other early/mid-20th century lighting technologies (fluorescent, mercury vapor) did indeed have more blue light content, typically with a nasty peak at the melanopsin wavelengths, but these were rarely used in living spaces (other than the kitchen). Until compact fluorescent lamps (CFLs) arrived, the biggest blue light threat in the home was from the blue phosphors of your color television’s relatively small CRT, and perhaps a lone GE Circline fluorescent over the sink.

The development of CFLs and then light emitting diode lamps (LEDs) has changed that, and living/sleeping space lighting with significant blue content is rising ominously.

Both CFL (as CCFL, cold cathode fluorescent lamp) and so-called “white light” LEDs are also used as backlights for liquid crystal displays (LCDs). This includes desktop monitors, LCD TVs, “LED” TVs, laptops, many tablets, many phones, car console displays and some appliances. These displays leak blue even when you think the blue is off.

It’s worth mentioning that OLED (AMOLED, PMOLED) displays can go fully blue-dark. They are direct surface emitters, and are increasingly used on mobile devices. They generate red, green and blue independently, which is both potentially the same blue hazard, but is also a hazard more easily mitigated than with any of the above.

Be careful of what you wish for.
For most of the 20th century, the holy grail for architectural (and photographic) lighting was Color Rendering Index (CRI); basically getting the artificial light to mimic daylight.
We got there.
Oops.
Yup, this is yet another novel pre-millennial era health threat, just like the rise of hybrid semi-dwarf wheat, HFCS, Omega 6 PUFA industrial oils, low fat diets, etc. It’s a threat we see rather than eat.

So what to do? Simple:
Reduce your retinal exposure to blue light starting at sundown, or two hours prior to planned sleep time.

Plan A: Blue Blockers

The most effective way to reduce your retinal exposure to blue light is right at the eyeballs. Get blue-blocking eyewear and don it at dusk or -2 hours, continuously until bedtime (and for any later bathroom trips).
OPO: Attenuation of short wavelengths alters sleep and the ipRGC pupil response

Your best bet here is probably the Honeywell UVEX brand, which can be had inexpensively from Amazon and similar resellers. If you don’t wear glasses, consider the S9133X. If you do wear glasses, get the S0360X. These work. At this household, the blue light sources either become green or go completely dark when viewed through these glasses (I was wearing a pair when this article was first authored). Chris Masterjohn favors Solar Shield brand in Amber, which are even lower cost.

Not Just a Central Vision Issue
It’s important to make sure that no blue light sneaks around the frames. The ipRGCs sites are apparently all over the retina, including in the peripheral vision. Your eyes are responding to skylight even when you are looking mostly at the ground. If necessary, wear a hat to close off the high sneak path.

Be cautious about buying random brand blu-blockers or just sunglasses with amber lenses. They may or may not effectively block the crucial wavelengths.

Plan B: Curtail the Blue Emitters

Do Plan A immediately, and work on Plan B as opportunities develop. It may turn out that there is some transdermal (skin) response to blue light, in which case eyewear isn’t a 100% solution. One trial suggested a transdermal effect, but wasn’t reproducible.

Do not rely on your eyes to determine the blue content of white or non-blue sources. Research the SPD for the lamps where possible. Due to the complexity of human color vision (principally metamerism), trust the SPD chart, and not your own lyin’ eyes. A pink light source, for example, usually contains a lot of blue, greens can, violets are certain to. I can think of a way a digital camera (capable of custom white balance) might be used to home test light sources for blue, but won’t get into it in the present article in the interest of space.

Get rid of blue light sources in your bedroom. Do it now. This includes clocks, night lights, weather radios, etc. For anything you can’t get rid of right away (smoke detector), cover the blue or green lamp or display with some amber, orange or red filter material. Roscoe medium amber filter gels do the trick. It doesn’t take much blue light (time or intensity) to disrupt sleep.

Get rid of other blue night lights around the home. Switch any electroluminescents from blue to green if you can. Put in red or amber bulbs where that’s an option. Put filter material over all the other myriad blue light sources (appliances, digital clocks, home entertainment gear, etc.)

You are probably already in the process of replacing your incandescent bulbs as they die off.
Skip CFL.
Go directly to LED,
and stick with quality LEDs for which SPD charts can be found that confirm low blue, or at least non-peaky blue. Most of the LED bulbs presently on the market have nasty blue light peaks.

Desirable products include Cree brand soft whites, which do not have a blue peak. Cree consumer products are at the moment a Home Depot exclusive in the US, but can be mail-ordered. If price is no object, consider the Philips Hue technology, which have discrete, variable, red, green and blue sources inside. You can program up to 50 Hue bulbs from one hub using your smart phone, and actually set them to routinely ramp down the blue at night. GE is now entering this market with their Align branding, and it is specifically promoted as a circadian aid.

Yard lights: have the power company replace that mercury vapor eyesore with high pressure sodium, or something else with no blue (or just get rid of it - your local astronomers will thank you).

Dealing with the Digital Display Blues

For a very few screen types (CRT, DLP, “laser”, plasma, OLED,  and LCD with local-dimming discrete RGB LEDs), fully turning down the average blue level in the signal actually does fully extinguish the blue light emitted from the screen. An app called "F.lux" can be useful with these display types. Getting F.lux into the signal path to your conventional TV screen could be a challenge, however. Getting F.lux for an Iphone is a problem at the moment, but one site speculates that Apple may be working on a standard solution.

F.lux still won’t fix blue indicator LEDs on your reader/tablet/phone. Put a filter or black tape on those, wear blu-blockers, or just stop using them at night. Consider the blue light issue when choosing a replacement device. See footnote on this mess.

A bigger problem is that the display you are probably reading this on is NOT one of the above technologies with fully dimmable blue. It’s probably an LCD screen with CCFL or “white LED” backlight unit (called a BLU, no irony intended). Your so-called “LED TV” is merely an LCD TV with an LED BLU. This was originally written on an older LCD with a CCFL BLU.

Typical BLUs are most likely at full intensity (including full blue) at all times. When you dial down the blue, you are at the mercy of LCD technology limitations, which cannot reach full black (terrible black level is one reason why videophiles are lamenting the passing of plasma TV). An LCD pixel is actually a triad of pels (picture elements) consisting of R,G and B micro color-filters, and three liquid crystal light valves, which use variable polarization to vary the light allowed through. Fully polarized is as dark as a pel gets, and it’s not sufficiently black to block enough of the blue. TN vs. IPS vs. VA doesn’t matter much here. LCD just doesn’t get truly black (that’s why higher end sets have “local dimming” or “full array dimming”).

Monitor makers are introducing “low blue” models with a blue wavelength shifted toward green, but if you care about daytime color accuracy, this is not a wise choice. You won’t even get 100% sRGB gamut, much less 100% NTSC or 100% AdobeRGB, and forget completely about BT.2020.

As we wrap up plan B, for extra credit: when you redecorate your home, don’t paint the bedroom blue.

Plan C: Take Melatonin and Tryptophan

Although you can (in most places) buy melatonin supplements, it presents challenges, not to mention risks. Like most dietary supplements, it’s not standardized or routinely tested (other than by consumerlab.com). Dialing in an exact dosage is tricky. There are potential side effects. Safety has not been determined for various cohorts like children, pregnant women, people with kidney/liver disease, etc.

As a medical non-professional, my prescription would be: don’t go there unless you have no other choice, or controlling blue light at night doesn’t help. Undoctored has some advice starting on 306. The need for melatonin might arise in cases of irregular shift work, or trying to switch between day sleep on workdays and night sleep on weekends. Melatonin is not in my view a complete fix for the circadian hazards of shift work or jet lag. Shift work, by the way, is classified by IARC as a group 2A carcinogen all by itself. The shift premium is no prize. Own a prostate?

Out of curiosity, I took a look at what consumerlab.com (subscription site) had to say about the supplement approach for circadian problems, specifically taking melatonin and tryptophan.

Melatonin is available in credible formulations, and CL has tested them. Dosage requires some dialing-in. There is a tangential concern about BSE risk if animal-sourced (no reported incidents).

Tryptophan is another matter. CL hasn’t even published test results for products due to an inability to be confident about potential contaminants. They recommend instead that you get it from foods, and listed quite a number. Eggs top that list, but it takes a kilogram of egg to get the typical 1 gram dose of tryptophan.

Plan D: Paleo Time Machine

Revert to a simpler pre-tech existence.
A time before Facebook (and its extra-toxic blue color scheme).
So Simple a Caveman Could Do It.
Yeah, that would work.

Dark Means Dark

It doesn’t take much light pollution in the sleeping space to provoke measurable neurological responses. Here’s a recent trial showing performance impairment beginning somewhere between 5 and 10 lux:
Nature: Decrease in fMRI brain activation during working memory performed after sleeping under 10 lux light

For some perspective, that would be like having 5 to 10 candles burning in the room. Ancestrally, sleeping under a clear sky overhead full moon is a mere 1 lux.

Conversely, get light exposure in the morning. Sunlight on the face is ideal (without eyewear). Don’t look directly at the sun, of course, but allow some direct sunlight to fall on the periphery of the retina. If you can’t get sun, investigate artificial light sources that mimic solar SPD, including the blues and possibly into the uV.

___________
Bob Niland [disclosures] [topics]

Footnote: Why are blue LEDs indicators so pervasive?
Well, they were rare and expensive, and became trendy as they became practical. Designers think they look “cool”, and indeed they do, in the color rendering sense. Early (1960s+) commercial LEDs were able to emit infrared through green relatively easily. Blue took much longer (1994). Why? LED fundamentally depends on quantum mechanics. The light arises from electrons falling between energy levels at a P-N (diode) junction of semiconductor materials, which materials are ideally transparent. The specific band gap, limited to discrete values (quanta), gives rise to the wavelength. The available energy quanta choices are limited by the periodic table, the expense of some rare earth materials, and processing costs and complexity. Even today most “white” LEDs are not discrete R-G-B LEDs mixing to white, but single-color (perhaps even UV) LEDs, which then filter, reflect or re-emit the generated light via a phosphor. Most white LEDs are little more than fluorescent lights based on a phosphor excited by an LED rather than by ionized mercury vapor. Blue LEDs may or may not be actual magnesium-doped gallium nitride pure blue LEDs. However the blue is generated, faddish gadget makers need to get a message: stop using blue LEDs, and stop using white LEDs with more than trivial blue content.
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