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How Artificial Light Is Wrecking Your Sleep, and What to Do About It

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blue light and sleep, blue light melatonin
Blue light exposure at night can adversely affect a good night's sleep. istock.com/IngaNielsen

“A good laugh and a long sleep are the best cures in the doctor’s book.” – Irish Proverb

The evidence for the health benefits of adequate, restful sleep is overwhelming. Decades of research has shown that sleeping between 7 and 9 hours per night can relieve stress, reduce the risk of many chronic diseases, improve memory and cognitive function, and may even help with weight loss. (1) As many of us know by now, getting adequate, high-quality sleep is one of the most important, yet under-appreciated steps you can take to improve your overall health and well-being.

Yet for all we know about the benefits of sleep, there are millions of Americans who are still suffering from disordered sleep and insomnia. More than one-third of Americans report getting less than 7 hours of sleep per night, and 63 percent of Americans say their sleep needs are not being met during the week. (2, 3) The negative effects of sleep deprivation are serious: sleep durations that are consistently shorter than 7 hours in a 24-hour period are associated with cardiovascular disease and diabetes risk factors, depression, automobile and workplace accidents, learning and memory problems, and an overall increase in mortality. (4) Some may argue that poor sleep can even undo the benefits of a healthy diet and exercise routine. (5, 6)

Could using electronics at night ruin your sleep and increase your risk of death and disease?#chriskresser #healthylifestyle #artificiallight #bluelight

So what’s causing this epidemic of sleep disruption in our country? Many experts feel that our excessive use of communications technology (e.g. cell phones, laptops, television, etc.) is driving this significant level of sleep deprivation. If this is the case, it’s no wonder so many Americans struggle with poor sleep, since 95 percent have reported using some type of electronics at least a few nights a week within the hour before bed. (7) Checking email, watching your favorite late-night comedian, or responding to a text message in bed seems harmless enough, but the sleep disruption caused by these light-emitting devices is significant and potentially harmful to your health.

Research has demonstrated that nighttime light exposure suppresses the production of melatonin, the major hormone secreted by the pineal gland that controls sleep and wake cycles. (8) Therefore, a reduction in melatonin at night is associated with subjective levels of sleeplessness. (9, 10) But melatonin suppression has far worse consequences than simply poor sleep outcomes: it has also been shown to increase the risk of cancer, impair immune system function, and possibly lead to cardiometabolic consequences such as type 2 diabetes, metabolic syndrome, obesity, and heart disease. (11, 12, 13)

With serious consequences like these, preventing melatonin suppression should be a top priority in anyone’s healthy lifestyle.

Blue Light and Melatonin Suppression

It is well established that short-wavelength or “blue” light is the most melatonin-suppressive; this is the type of light typically emitted by devices such as televisions, computer screens, and cellphones. (14, 15) To produce white light, these electronic devices must emit light at short wavelengths, close to the peak sensitivity of melatonin suppression. (16) This means that products such as tablets, smartphones, and other devices with self-luminous electronic displays are major sources for suppressing melatonin at night, thereby reducing sleep duration and disrupting sleep. (Figure credit: Wood et al, 2013)

Melatonin graph

Along with blue light emitted from electronic devices, research has shown that being exposed to normal levels of room lighting can have similar negative effects on melatonin. One study showed that one hour of moderately bright light exposure (1000 lux) was sufficient to suppress nocturnal melatonin to daytime levels. (17) Since melatonin suppression is intensity dependent, researchers suggest that lower intensities can have similar suppression effects at longer durations; for example, two hours at 500 lux would have a similar effect as one hour at 1000 lux. (For examples of lux values, check out this helpful chart.) This means that typical room light alone can have a similar suppressing effect on melatonin secretion as the light from backlit screens. (18)

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How to Prevent Melatonin Disruption (Without Tossing Your iPhone)

Since it is predominantly the blue wavelength that is most affective in melatonin suppression, it stands to reason that blocking this wavelength of light should be enough to significantly reduce, or even eliminate the melatonin-suppressing effects of nighttime light exposure. (19) In fact, blocking blue light has been shown in several studies to be extremely effective in reducing the melatonin-suppressing effects of intense and/or blue light. (20, 21)

There are a few possible solutions for reducing your exposure to blue light at night. One that is commonly used in the ancestral health community is f.lux, a program that makes the color of your computer’s display adapt to the time of day, warm at night and like sunlight during the day. This program can be installed on computers, iPads, and iPhones, and may have a significant effect on your melatonin secretion when using these devices at night. The best part about this program is that it turns on automatically in response to the daylight in your particular time zone, so there’s no need to remember any adjustments to the screen.

A better option, in my opinion, is to use amber-lensed goggles once the sun has gone down. These blue-blocking lenses are highly effective in reducing the effects of blue light exposure, and in most cases completely eliminate the short-wavelength radiation necessary for nocturnal melatonin suppression. (22, 23, 24) These goggles have been shown to improve sleep quality as well as mood, simply by blocking blue light and simulating physiologic darkness.

The main reason I recommend using these goggles is because normal room light alone is enough to suppress melatonin at night, and unless you’re shutting off all the lights in your house when the sun sets, you’re still at risk for disrupting your melatonin-driven circadian rhythms. (25) While f.lux is a useful tool for your backlit devices, it’s nearly impossible to address all sources of melatonin-suppressing light in today’s world of modern technology and late-night work and entertainment habits. Amber-colored goggles are one of the only tools available to completely eliminate all blue light exposure at night, without ‘going off the grid’ and powering down your entire house after 7 PM.

There are two excellent (and cheap!) options for amber-lensed goggles on Amazon. The cheapest and most popular option is the Uvex brand, but if you wear eyeglasses you’ll need to get a wraparound pair like the Solar Shield brand. I’ve had many patients swear by these goggles, and if you can get over the dorkiness factor, you may find they make a big difference in your sleep quality, and perhaps even your general health and wellbeing as well!

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435 Comments

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  1. What about red blocking glasses for day use to help establish circadian rhythm?

    • Special glasses wouldn’t really do much. Warm light doesn’t technically trigger melatonin production — in reality it just doesn’t block it from being produced. So, you can have a bonfire on a sunny beach, but the bonfire won’t make you sleepy because even a small amount of cool sunlight is all you need to prevent melatonin during the day. The temperature of daylight is already perfect as it is — at least from an evolutionary standpoint — so there’s not really any need to toy with the light from the sun.

      http://i-cdn.apartmenttherapy.com/uimages/re-nest/4_14_2008-colortemp.png

      There are special lights that people can use to establish circadian rhythm. The lights have some risks to the eyes (i.e. UV damage) but they can be very beneficial in places where sunlight is difficult to obtain at different times of the year. But, for most people, simply getting some sunlight into your house early in the morning is all you need to establish circadian rhythm.

  2. I’ve been using f.lux for about 2 years and it makes a humongous difference , especially if you work on your computer at night. There was one night I turned it off because my computer was running slow and I nearly was blinded at the light my computer was emitting! I just purchased the amber-lenses . I know they’ll be of great help.

  3. Chris,
    Just wanted to say thank you for the good information on the talk you gave with the Village Green Network yesterday. Very informative and helpful.

  4. Hi Chris, have you looked into the effect that sodium fluoride (which is in tap water amongst many other things) has on circadian rhythms and on the pineal gland/the production of melatonin? If so, I would be very interested to hear what you think about it.

  5. Last night I gave myself 2 hours in a room with a lamp plugged into a dimmer, dimmed so it looked orange, and a tv on movie picutre mode (not dynamic or standard), and all other little led’s covered in socks. I found myself randomly looking away from the tv to rest my eyes. At the end of it, I felt like I had taken a strong sleeping pill.

  6. How about the light receptors on our skin?
    Artifical light on skin after sundown messes with melatonin too. Is it best to cover up after sundown too? As well as the glasses??

    • Earlier in this thread, it was made clear that the one study that claimed that exposure of the skin to light suppressed melatonin production could never be replicated. The effect is entirely through the eyes. (We do need sunlight on our skin to produce vitamin D)

  7. Is there any way to adjust the focus on the Uvex orange safety glasses? I can’t focus on things close, like my phone or a smaller font on the computer.

    As long as you have a dimmer and your light isn’t LED, dimming it will make it more ‘orange’.

  8. Or… One can simply take 1mg of melatonin and be 100x ahead of the game. And not look like an imbecile wearing sunglasses indoors.

    Think about it.

    • 100x times ahead of the game? Oral melatonin dosing can be highly variable from one person to the next and the timing is crucial as taking it at the wrong time can reset the internal clock and promote insomnia when you want to sleep.

      The glasses are just a return to pre-electric lighting as far as the body is concerned. Far safer and cheaper.

      • Kudos, I agree. Taking Melatonin and the wrong time can mess you up even more…..Glasses are easy…

  9. Yes! I love F.lux! I have it on my computer, but had no idea I could install it on my iPhone and iPad. I’ve never tried the goggles, but that could be fun too. Thanks for the tips!

  10. Any suggestions for those of us that work the graveyard shift? I work a 12.5 hour day with a crazy to explain schedule basically 4.5 days one week and 3.5 days the next and due to kids schedules I switch back to a “normal” schedule on my days off.

    • There is an entire chapter dedicated to a graveyard shift protocol for using the low-blue glasses in the book, “Great Sleep! Reduced Cancer!: A Scientific Approach to Great Sleep and Reduced Cancer Risk,” by Richard L. Hansler (http://amzn.com/1419690388).

      The book is very cheap (less than $5) and it will walk you through the steps of using the glasses at the right time to create a circadian rhythm. Well worth the price.

    • Hi Jenn,
      It is important for you to know that in 2007, the World Health Organization degreed shift work as a probable carcinogen due to circadian disruption by artificial light at night disrupting their ability to produce melatonin.
      I believe that all businesses and institutions who employ shift workers ought to notify their employees of the health risks, pay them more because of these risks, and educate their shift-worker employees how to minimize their risks and train their circadian to produce melatonin naturally. Not to do so, would be similar to hiring employees to work with asbestos without adequate warnings and training. btw, Belgium employers have already begun monetary compensation for their cancer victims when linked to shift-work.

      • Fascinating. As a midwife, I am faced with unpredictable sleep disturbances, without any rhyme or reason whatsoever. I just do the best I can. I wonder now if this had to do with my nurslings’ poor sleep. Perhaps since my melatonin levels were deranged, theirs were too.

  11. I am so lucky that I sleep well, and always have, regardless of whether I use devices before bedtime or not.

    My question is though, my room is never dark due to street lights outside shining in my window all night. Could this ambient street light be affecting my melatonin production during sleep, and should I do something about?

    I guess in nature we would sleep in absolute darkness (except perhaps for fire light).

    If this is the case (even though we’re not necessarily aware of it, and still sleep well) would an eye ‘patch’ such as you get on airplanes, or blackout curtains, be a good idea?

    • Fire light does not affect melatonin production since the color temperature of firelight is less than (i.e. warmer) than sunrise. Oil lamp, candle and fire light are all warm (low blue) light (~1800ºK). Sunrise starts at 2000ºK and quickly increases by the minute to higher (bluer) color temperatures. So, melatonin is affected by color temperature and intensity. Your eyelids are purposefully thin so that you don’t miss the blue light at sunrise when your eyes are closed.

      If you close your eyelids and can notice a significant difference in the amount of light when either you cover your eyes or you don’t, then it probably is affecting your melatonin. But, if it’s only a slight difference, then it probably won’t make that much of a difference. But, generally speaking, it depends on the color temperature and intensity of the light entering the room.

      • And just to clarify, color temperature in degrees Kelvin increases as your light becomes more blue and decreases in degrees Kelvin as it becomes more amber. Fire light is very “warm” (low blue) so it has a lower color temperature. Sunlight is “cooler” (high blue) so it has a higher color temperature in degrees Kelvin. It’s confusing, and somewhat backwards.

        To illustrate this, see this chart:

        http://upload.wikimedia.org/wikipedia/commons/7/7e/Incand-3500-5500-color-temp-comparison.png

        The reason why electric lightbulbs suppress melatonin is because the “warmest” tungsten lightbulb you can get at Home Depot starts at 2,700ºK. Even a 60W bulb has too much blue light and is not low enough on the color temperature scale:

        http://i-cdn.apartmenttherapy.com/uimages/re-nest/4_14_2008-colortemp.png

        A light bulb would need to be around 1,800ºK in order to replicate fire light — which does not suppress melatonin. And again, sunrise starts at 2,000ºK and quickly increases from there.

        Lowbluelights.com sells lights that are very low color temperature and do not suppress melatonin — they are perfect for a nursery when mothers need to nurse and babies need to keep their melatonin flowing on a particular rhythm. It basically just simulates fire light. You know, the same light people have been using for millions of years up until electric lights were mass produced.

        Incidentally, the only intense blue light that our ancestors were exposed to at night would have been a full moon. And it’s no wonder that full moons were always associated with mischief and weird behavior. Perhaps it was from everyone’s melatonin being disrupted!

  12. I just installed f.lux on my laptop. Now my screen is orangey. But I’m going to try it. I hate any light in the room. My husband says I am a vampire. He likes to have light. I usually go to be before him and I try to make the room very dark. When he was away for a week, I was in heaving with a completely dark room. Maybe I should get a sleeping mask.

    • These glasses arrived last week. They’re reasonably comfortable and do the job just fine.

  13. Hi Chris – thanks so much for this article. I have had lots of trouble sleeping and so far the best remedies are limiting stress and not working after a certain point each night. The modern work life unfortunately seems to be a slow death by sitting and computer brain drain. I’ve tried f.lux but unfortunately it violates my work’s Internet security policy! I’m going to try the amber glasses because part of my daily de-stress routine involves TV episodes of Modern Family. A good laugh never hurt anyone.
    I do have a question for you though – when I have the opportunity to expose myself to sunlight should I not wear sunglasses in order to maximize exposure? Or is the potential damage to my eyes not worth the risk?
    I live in MN and during the winter I’ve avoided wearing sunglasses to maximize natural sunlight exposure unless it puts me at risk for a car accident. (Which is rare – seems the gray winter days are unending this year!)

    • Sarah,

      Sunglasses won’t make a difference in terms of vitamin D production, because it’s light hitting skin that matters. You should abstain from sunglasses for the first 20min or so however because your body’s natural sunblock chemicals are light-activated from your eyes. Putting them on after 20min will mean max skin and eye protection and continued vit D creation. I believe i read this in the book ‘survival of the sickest’.

      • Thanks for the information! I’m more concerned about the melatonin production than vitamin d. Since the vitamin d production to your point is done through light hitting skin – I have to supplement or hit the electric beach in the winter since the only skin I ever have exposed in the winter here is my nose. I doubt that will do much to help produce vitamin d! My trip to FL in the next month will help. It’s my understanding the melatonin production is stimulated through the light exposure in the eyes. That is why I’m questioning if I should always avoid sunglasses in the winter months to maximize the light exposure. But maybe it doesn’t matter? It would be a trade-off with melatonin production and crows feet around my eyes from squinting. : )

  14. I was wondering if you guys think regular blue-light blocking polarized sunglasses would be similarly effective as the Uvex brand – they block UV and blue it states, but also some percentage of the rest of the visible spectrum. Do you guys think normal sunglasses would block too much in a dark environment, such that a cheap blue-blocking only pair would be better for doing things at night?

  15. Interestingly, I find that using the Internet within an hour before bed, even with F.lux installed, the brightness turned all the way down, and orange goggles on, still disrupts my sleep–it takes longer to fall asleep, I wake up more easily and more often, and feel more groggy when I get up.

    I suspect that there is something uniquely stimulating, and thus sleep-disrupting, about using the Internet. The instant access to an endless supply of information, the surrogate social interaction, the visual and cognitive stimulation…all of this is highly discordant with the evolutionary environment, or even with the post-agricultural human environment prior to the 21st century.

    My sleep is of the highest quality when I strictly avoid using the computer at all after sundown. Reading a book, meditating, or playing/listening to music in low light (preferably candlelight) seems to work the best for improving my sleep, mood, and everything else.

    • For what it’s worth, I’ve noticed the same effect Brendan. I guess it shows that there’s rarely one “fix” for anything – life and our bodies are too complex for that.

      But of course everyone still looks for what “the” problem is! 🙂

    • You’re absolutely right, Brendan. I couldn’t have said it better: “I suspect that there is something uniquely stimulating, and thus sleep-disrupting, about using the Internet. The instant access to an endless supply of information, the surrogate social interaction, the visual and cognitive stimulation…”

      I intend to get the Uvex glasses mentioned, but the behavior has to change as well. When I go to bed late after being on the computer–for any reason–and I can’t sleep, I realize it’s because my mind has been so active. I’m either caught up in the story of a movie, or thinking about the email I’m composing, or absorbing new information when doing health research…and when the little wheels in my mind are spinning fast, they don’t just stop when I lie down, even if I’m not consciously thinking about any of those things. It’s the focused concentration. Maddening. I wish I could just flip a switch, but if I want to get good sleep, I’ll have to curtail my activities.

      • Being on the computer, iPad or the Kindle Fire at night is too stimulating for me as well. I now try to stop all electronics by 7 or 8 PM. The only exception is the Kindle Paperwhite – I read on this device and turn the brightness all the way down (increase the font) and read not too exciting books. I would rather read this way than with a hard copy book and a bright book light.

    • It’s not that – it’s that green light also disrupts melatonin production. Any frequency lower than yellow does. If you look through the scientific papers on color and melatonin, you’ll find a neat bell curve.

      From my personal experimentation, when I wear red laser-safety glasses that block any frequency up to 570nm (reddish-orange) with an optical density of more than 5 (i.e. 99.999% of the light is blocked), I can hang out on the Internet until the cows come home and still sleep like a baby. Orange goggles don’t work nearly as well.