The Surprising Way Blue Light Impacts Mental and Physical Health

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The innocuous hazard of blue light has finally captured the attention of researchers. The profound negative impact of blue light on our circadian rhythm, has PMHNP’s and primary care providers paying closer attention. How could a preventable health risk like this go unnoticed for so long? Learn the importance of recapturing circadian health and the tremendous impact this has on your client’s well-being.

In 2017, a key discovery challenged the dogma of traditional science textbooks. Melanopsin was discovered in our subcutaneous fat (not just the eye)  (Ondrusova et al, 2017). Melanopsin was previously thought to solely exist in the eye, as a blue light sensitive retinal protein. Melanopsin’s chief function, is to detect blue light and relay that critical information to our supreme human clock, known as the suprachiasmatic nucleus (The SCN). Our skin can now be thought of as our “third eye”.

When your external clues (Zeitgebers), do not yoke with your circadian rhythm, you have chaos in both the mind and the body. Imagine a compass that can’t make up its mind regarding north or south – Is it currently day or night or maybe both? Our peripheral clocks require a valid and reliable answer.

What happens when you fool your internal clock?

In 2012, the Harvard Health Letter published an article which discussed a link between nighttime blue light exposure with obesity and diabetes. Oddly, this message was not widely shared. The importance of maintaining a circadian rhythm is often reduced to the waste basket term “sleep hygiene” and the avoidance of caffeine after midday. Blue blockers were half-heartedly mentioned (more on blue blockers later), but recall that in 2012, researchers had no idea melanopsin was in our skin, our largest organ. The skin continues to be overlooked, thought of as a sack-like container, without a special role, just wallpaper for our tissues.

Blue light has now been linked to cancer

Why do third shift nurses die before the rest of us?

Did you know there is a relationship between disruptions in circadian clock and cardiovascular risk? (Thosar, Butler, & Shea, 2018). Even more concerning, night shift work is directly associated with breast cancer, cardiovascular mortality, cancer mortality and all-cause mortality (Hatori et al, 2017).

Who can honestly justify the benefits of a 3rd shift pay differential, given the massive impact on one’s health?

It is not just women, or nurses for that matter. Any person who is routinely awake all night, is at additional risk for disease. Japanese men working 3rd shift have an increased risk of death from extrahepatic bile duct cancer (Lin et al, 2015). Even more shocking,  just 3.5 days of consecutive night shift work is sufficient enough to compromise insulin sensitivity in young lean men (Wefers et al, 2018).

Ok, so how bad is working a few years of  night shift?  Female nurses working rotating night shifts for more than 5 years had a modest increase in CVD mortality and those working more than 15 years have an additional increase in lung cancer mortality (Fangyi et al, 2015).

Take a second to ponder this data? Could the light environment one is forced to work under, destroy melatonin production?

Blue light spectrum of LED bulb

So, where is this blue light?

Don’t most lights appear whitish in color? Blue light is a part of the visible solar spectrum that is largely balanced by the red spectrum of light. The appearance of a white light in a prism illuminates a rainbow of colors or frequency. In the last decade, we changed the balance ratio of the blue/red light dramatically with the invention of something called the white LED bulb. This invention was designed to save the environment, but not necessarily the humans inhabiting the environment.

LED’s give us bright light, at a much lower temperature than a bulb with red light (incandescent bulb) and this is what makes the bulb cost efficient.  LED’s have peak emission in the blue light range (400-490nm). Some of the most powerful LED’s are labeled “cold white”. They are quickly becoming the corporate office favorite. Ever wonder why many office dwellers complain of eye strain and migraine headaches? The spectrum of intense blue, with its closely related tech cousin (think tablet LED), harm the retina while disrupting sleep.

Blue light from visual display terminals lowers the stability of the tear film, causing ocular damage (Xu, Qu, Chen, & Zhang, 2018). Going deeper, we know that blue light effects the epithelial cells of the ocular surface inducing cell death while driving reactive oxygen species into over-production (Marek et al, 2018). Blue light causes photoreceptor damage (Tosini, Ferguson & Tsubota, 2016).

Mother nature intended nighttime to be free of the blue light spectrum for a restorative reason.

In nature, there are longstanding associations of insomnia and exacerbations of mental illness during a full moon (origins of term lunatic).  On the artificial light side, the unbalanced blue spectrum is foreign to the human eye and skin and thus falls under a category called nnEMF (non-native electromagnetic frequency). Blue light toxicity can eventually lead to macular degeneration, one of the common leading causes of blindness (Kasun, Payton, Lakmal & Karunarathne, 2018).

Blue light destroys melatonin, which plays a role in post-partum psychosis and depression associated with bipolar disorder. Researchers have explored the link between environmental decreases in melatonin in bipolar disorder and its contribution to post-partum disorders (Anderson, 2010).  Exogenous melatonin significantly reduced the risk of depressive symptoms in women with breast cancer during a 3 month period of time post operatively (Hanson et al, 2014). If exogenous melatonin can help fight cancer in its artificial pill form (exogenous medications have the potential to ruin negative feedback loops) imagine the benefits of melatonin secretion, the way nature intended, with darkness prompting automatic production?


It is no surprise that Insomnia is now a common problem. If you are over the age of 35, you have probably noticed a decrease in your sleep quality. Gone are the days of waking up at 8 am with drool on the pillow after a solid 8.5 hours of blissful sleep. Likewise, many of your clients continue to complain of “not sleeping well” and many request sleeping medications. The good news is that sleep can be manipulated, hacked and addressed without adding medications and in many cases, deprescribing becomes an option.

Most practitioners do not have a firm understanding of circadian rhythm or light effects. The old school Freudian clinicians assume that Insomnia is secondary to unconscious conflict. The lay public blames stress as the culprit. Although both have some truth, we far underestimate the power of light.  The pharmaceutical world offers many temporary solutions, but all these drugs come at a steep price. Not just financial, but morning grogginess, disorientation, headache, fall risk, aggressiveness, psychomotor impairment, sleep walking and the potential of dependence & withdrawal.

Insomnia is characterized by difficulty initiating or maintaining sleep. The prevalence of insomnia is approximately 10-20% (Buysse, 2013). Quality sleep, the so called 5th vital sign in mental health, is more challenging to come by, in the era of the smartphone and LED everything –However, we do not have to work third shift to suffer from various effects of a third shift work lifestyle. In fact, there are dose dependent associations between sleep duration and unsafe behaviors among high school students (Weaver, Barger & Malone, 2018).

Most concerning, we now know that shorter sleep duration predicts next day suicidal ideation (Littlewood, Simon, Carter & Peters, 2018) With this information, you should now prioritize the importance of assessing sleep disturbance, in working with clients who are actively experiencing suicidal ideation.

Camp fire at night mostly red spectrum

Nature designed nighttime to be a restorative process that requires the absence of light, especially blue light. The red spectrum witnessed by our ancestors, like when gazing at a campfire, does not compare to the intense blue light color temperature of one’s iPhone. Just a brief glance at the smart phone at night, sends a faulty signal to the brain screaming it is solar noon!

Smartphone viewing distance has been correlated negatively with subjective sleep status. The closer the phone, the worse the sleep (Yoshimura et al, 2017).  Overtime, poor sleep insidiously accelerates illness, promotes cancer and expedite death. Sound too dramatic? Its not. Let’s explore the literature and science a bit further. Melatonin is a natural antioxidant that modifies various cells within the immune system. It is a hormone manufactured by the pineal gland in the brain.

Most people associate melatonin with something that helps control sleep and wakefulness. We know that melatonin plays a much larger role in our health and overall well-being.  Melatonin has anti-inflammatory and antitumor effects (Fernandez, 2015). Melatonin is involved in aging and longevity.

Melatonin’s most important critical functions are autophagy and apoptosis.

Without properly functioning autophagy (cleaning out the dysfunctional components of a cell) we are at heightened risk for major neurocognitive disorders (dementia) and cancer. Autophagy is thought to be increased at night during REM sleep, as mitochondria release heat, (infrared light). Without highly regulated apoptosis (programmed cell death), one would lack the necessary antitumor effects to keep cancer at bay or even worse, cancer cells disable the failsafe mechanism of autophagy itself.

Melatonin has been shown to enhance the anti-tumor effects of cisplatin, in gastric cancer cell lines (Li, 2015).

Circadian Rhythm and disease

What happens to Melatonin as we age?

The production of melatonin decreases as we age. No surprise then that cancer incidence increases as we age.  Thus, centenarians have an extremely high degree of heteroplasmy, as mutations increase with age. How do younger folks ruin the vital processes of autophagy and apoptosis? With light of course! — Especially blue light after sunset. Melatonin secretion starts around 9PM and tapers off by 730 AM. However, nighttime blue light changes the game and destroys the entire process. Just a small dose of light at night can affect one’s sleep quality.

Yes, you should think of light as a drug.

This in turn, helps fuel common types of cancer. In fact, artificial light at night is directly linked to prostate cancer (Smolensky, Sackett-Lundeen & Portaluppi, 2015). Short wave visible light disturbs the production of melatonin in such a degree that it amplifies the risk for breast cancer (Mortazavi & Mortazavi, 2018). This is especially important for women who carry the BRAC1 or the BRAC2 gene. That said, there are solutions that are easy and affordable ways to modify your environment and offset this risk…more on that later….

What are the benefits of artificial blue light?

Evidence exists supporting the treatment for seasonal affective disorder (SAD) with (artificial) light therapy (Meesters, Winthorst, Duijzer & Hommes, 2016)  However, this isn’t a novel mechanism. Humans after all, were designed to be addicted to light…we were designed to require the sun.

Proper AM sunlight exposure sets the stage for the day and provides signal instructions for our hormone production and cessation. Take a second and think about how perfectly we were designed and motivated to seek out a sunny day, which plays a vital role in creating our dopamine. Solar exposure is required for all life forms on earth. For this reason, blue light was intentionally designed to be addictive. Nature built us that way, so we would feel… depressed…when we avoid it. However, nature never imagined for us to divide up the solar light spectrum and dose it at our leisure, at all hours of day and night.

AM sunlight is critical to health

What about the sun? Does the sun have blue light?

The one EMF that we are designed to work with – is the sun. That yellow ball that your precious preschooler drew in her first pictures, is one of the most misunderstood and demonized stars in our existence and yet is the most vital factor for earth’s well-being. The sun has been around for a while and is now considered “middle-aged”.  The fields dermatology and ophthalmology continue to unfairly prejudge the sun, especially in the last 40 years.

Why bet against mother nature and her 4.6 billion years of existence, over an unfinished story, that we continue to learn from? In fact, the most telling study regarding the importance of sun showed that women whose 25(OH) D levels were above 60 ng/ml had 1/5th the risk of breast cancer, compared to those women with a level of 20 ng/ml! (This shows that vitamin D has an associated protective effect against breast cancer). Most persons only require 20 minutes of sun exposure between the hours of 11 AM and 3 PM to make adequate vitamin D during summer months.

However, the debate continues how we should obtain Vitamin D. What is the difference between natural sources of Vitamin D vs. exogenous (pill form) version of Vitamin D? Could this be this be why several studies of Vitamin D have various outcomes? With a pill, you skip the key steps that occur during UVA radiation.

Lowering Blood Pressure via the sun

When then skin is stimulated with UVA radiation, nitric oxide is released, which activates vasodilation and thus lowers blood pressure naturally.  UVA exposure drops the diastolic BP by 5mmHg which is equivalent to decreasing stroke risk by over 30% (MacMahon, 1990)! In the future, studies should consider humans residing in equatorial regions, who obtain adequate sun exposure. Then, compare their health outcomes to humans who inflate their Vitamin D status orally, while residing in a northern latitude, such as Alaska.  In summary, the effects of delivering vitamin D exogenously, without triggering the natural biological cascade of events from solar exposure, remain largely unknown in 2018.

Recall that flight attendants are blue light toxic and solar deficient

Interestingly, in 2018 flight attendants were discovered to have higher prevalence rates of several cancers, especially breast, melanoma and skin cancers despite low smoking and low obesity levels compared to the general population (McNeely et al, 2018). This included melanoma! –but wait, you mean to tell me one can get melanoma without an abundance of sun exposure? How could this be? Could this be related to the lack of sunlight, circadian mismatch,  a steady bombardment of nnEMF or all of the above?

Why do persons with the lowest levels of Vitamin D, have the highest rates of melanoma? (Cattaruzza, 2018) –Dermatologists hate that question! Why do dermatologists continue to treat various skin conditions, like plaque psoriasis, with UV light? Because it works. Hmm, so by now you are probably scratching your head….

How can the sun be dangerous and healing at the same time?

Researchers continue to debate this. We know that solar exposure has been shown to have negative effects in certain populations, in a dose dependent manner. A fair skinned person, who burns easily would need to take extra caution in the midday sun, especially in the summer. We also know that sunscreen remains universally recommended for the foreseeable future. Interestingly, sunscreen can alter the natural ratio of UVB to UVA from normal solar exposure. UVB is responsible for the upregulation of melanin synthesis and helps protect us from UV damage (Miyamura et al, 2011). We also know that sunscreen impairs Vitamin D synthesis. With impaired Vitamin D synthesis, one has increased risk of all-cause mortality, including melanoma.

Several sunscreen ingredients from the year 2000-2008, have already been banned in the EU. PABA for example, was shown to increase DNA defects. PABA remains permitted the USA. As a health professional, have you ever contemplated discussing the pros and cons of solar exposure with a patient? In persons who remain steadfast against solar exposure, would advocating for the shade and protective clothing be a safer option? Equally interesting, is melanin, our natural skin protectant. Melanin is produced from tyrosine (Hmmm…we know that tyrosine is also precursor to dopamine). Melanin is a pigment that absorbs UV light and causes our skin to darken. Melanin protects us from excessive UV damage. Persons with the darkest skin, have the most concentrated melanin and thus the lowest incidence of skin cancer.

How does the body know how much of our natural sunscreen to produce each day? This process starts with sunlight recognized by your eyes and skin.  Sunglasses may affect this signal, blocking  AM sunlight, to a degree we do not yet fully understand. Hopefully future studies will explore skin melanoma rates of those who do and don’t wear polarized sunglasses.

Lastly, recall that dopamine is synthesized in the substantia nigra from tyrosine. Dopamine levels are boosted from solar exposure (Tsai et al, 2011).  Our skin produces beta-endorphin in response to UVB exposure. When dopamine is made from anything fake, meaning other than our sun, the dose is not well controlled. This should make one think about the disorder we call opioid addiction.

Vitamin D and friends  

Without quality sleep one is at heightened risk for mood disorders, cancer and death. Our society has lost touch with a normal circadian rhythm and we have become completely addicted to blue lit devices. Depression and suicide are on the rise. Vitamin D deficiency is also rising. Vitamin D, A and K2 have a special bond that requires balance and precision. Too much vitamin A or vitamin D is associated with toxic side effects. Recall that an Opsin is a light sensitive protein. Opsins are thought to be held together via a fragile covalent bond. Blue light is thought to destroy this bond. When Vitamin A is unbound to Vitamin D, Vitamin D levels will barley rise.  Many clinicians struggle to raise their patient’s Vitamin D levels despite massive doses of exogenous Vitamin D.

Recall that mice are often utilized for most of today’s research. Mice have scotopic retinas which allow them to see under lower light conditions. It is currently thought that mice are more impervious to the effects of blue light. Humans primarily utilize photopic vison and have much different rod/cone ratio than mice. With this understanding, you can begin to appreciate why many studies may lack translatability to humans. UV light generates melatonin and vitamin D3. Without melatonin, sleep quality is poor. When sleep is of poor quality, autophagy is reduced and thus morbidity rises.

In summary, most of us are blue light toxic, especially at night. Most of us are Vitamin D deficient, spending 95% of our existence indoors. We have recently witnessed a life expectancy drop for the first time in the USA in 20 years. We have no reassuring data that this was a fluke. We have also witnessed an unprecedent rise in suicide in the USA. Could part of the solution be as simple as living like the flintstone’s and not the Jetson’s? Time will tell –in the meantime – What can one do to maximize sleep and circadian health?

Fred Flintstone grounded to the earth in the sun

How do I block excessive blue light

Natural daytime blue light from the sun is necessary for our health. The dose we need varies depending on time of day, time of year, skin color, latitude and several other key factors that are beyond the scope of this article (for example; population density). One should try to get AM sunlight whenever possible. Discuss your individual Vitamin D needs and risks with your health care provider. Additionally, one should talk to their health care provider about how to maximize sleep and discuss blue light. One should consider avoiding blue light after dark to maximize circadian function.

Recall that we are diurnal animals and the studies mentioned above clearly support that fact that we were not designed to be nocturnal. The graveyard shift is labeled as such for an obvious reason. Consider blue blockers at night, when indoor blue light is unavoidable. Avoid wearing blue blockers outdoors or when driving. Few studies have explored the health benefits of blue blockers and no study has controlled for skin exposure despite the 2017 findings in when melanopsin was discovered in the skin (Ondrusova et al, 2017). Furthermore, you should now grasp this statement — sitting on your couch at night, under blue light LED lights, lounging in minimal clothing, may diminish the benefits of your blue blockers.

What signal are you sending your brain at night? Is it day or is it night?

Where can I find Blue Blockers?

RA Optics is currently considered the gold standard for providing the highest quality blue blocking lenses. They have a wide selection of lenses, with prescription lenses available. They sell daytime yellow tinted lenses for heavy indoor technology and screen use. Yellow lenses block light frequencies below 450nm. Ra Optics provides red tinted glasses for night use prior to sleep. These red tinted glasses block all frequencies of light below 550nm, which includes all blue light and green light. These are professional grade glasses, and some people will get noticeably tired after 30-60 minutes of use. Avoid driving with blue blocking glasses, avoid outdoor use and discuss blue blocking with your healthcare provider. According to RA Optics, all products are noted to come with a 100% satisfaction guarantee. Save 10% off the total purchase with coupon code: Lantern

Note: The majority of recommended resources within this website are free. I personally own several pairs of RA Optics. The quality is awesome. I recently contacted RA Optics and asked them to consider contributing to the Lantern PMHNP scholarship fund. Therefore,  in the future, I may receive a small affiliate commission from RA OpticsThere is no extra cost to you.  I only recommend products that I use for myself and have a lot of experience with.  Remember that for each resource, there are plenty of other options out there – these are simply the best that I have found.

For budget conscious folks who want to block blue light before bedtime and are beginning to dabble in circadian health, consider BioRhythm glasses. This orange tinted blue blocking glasses come with a nice curve to minimize unwanted peripheral blue light. BioRhythm glasses block 450 -510 nm and offer a solid value for the cost.  Please note, the quality is not the same as RA Optics and there is no additional option of adding prescription lenses.


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