Dr. Alexander Wunsch is a physician in Germany of holistic medicine and photobiology. He is the CEO of medical lighting consulting in Heidelberg Germany.

I wanted to speak to Wunsch because he’s very knowledgeable about the sun, light, circadian biology and other topics that interest me.

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We cover the sun, light and it’s health properties, the circadian rhythm, and rules for daily healthy sunlight exposure (hint: sunbathing naked at noon for 20 minutes).

Sun + Circadian Rhythm

Q: How does the sun interact with the circadian rhythm? What is the main thing that is setting the circadian rhythms?

A: Chronobiological, seasonal rhythms are also important.

All things: signals from the skin, from blood, from endocrine system-vitamin D as an example, receptors in eyes (play a role because they give us signals regarding our environment), specific receptor system which is a non-vision forming system-these receptors are susceptible to blue light and will directly influence the mid-brain, therefore being responsible for some hormonal adjustments.

(The colors, the content of blue, and the ultraviolet radiation, which acts onto the skin, are responsible for the circadian seasonal setting).

Daily Sun Exposure


Q: What are recommendations for duration of sun per day?

A: Difficult to give valid recommendation because you have to find out on your own. It’s individual-have to learn how your body reacts. Start with 5 minutes if the season and time of day is right.  After 3 or 4 hours your skin will tell you if you got a good dose or exceeded. You can double each day, for example do 10 minutes the next day, and so on. Of course there is a certain limit. You shouldn’t exceed 30-40 minutes depending on skin type and light tolerance of skin. Good advice is to not exceed 1 hour even if you are accommodated to the sun. It’s always a question of dose-there are benefits and negative aspects.

Q: How would someone know if they are getting too much sun?

A: If they burn they are definitely getting too much. In phototherapy we are looking for an erythema (reddening of a skin).

Q: Time of the day also matters. i.e. If we are getting sun from 8am-10am, can we stay out for longer?

A: He would never say 1 hour is the correct dose because you have to evaluate your personal tolerance. For example, a person who is skin type 1 (red head) may not even stand 20 minutes even after adaptation to sunlight.  In the early morning or late afternoon you will never get the full benefits from sunlight because from what we know today, the beneficial radiations is the ultraviolet B, and you can get the highest portion of UVB at noontime. Recommendation from CIE (International Commission on Illumination) is to expose large areas of your skin, but then for a relatively short time, which means 20 minutes naked at noontime gives you the highest benefit and lowest risk.

Q: When is risk highest, because you’re getting UVA in the am, and UVB in the noon, and generally UVA is riskier than UVB.

A: There was a development in photobiology in former times. Estimation was UVA is harmless and UVB is the harmful radiation because it makes you sunburn. But in the meantime we have realized that we need both-UVB, UVA, and we need it in a good ratio.  High vitamin D production is optimal at noontime.

Q: So you think somebody should mainly focus on getting sun in the afternoon because you’re going to get the full spectrum?

A: In the earlier afternoon you don’t get the full spectrum, and in the late afternoon, you might get a tan, but you will not get the medical benefits from vitamin D production. If you get the sun at noontime you can reduce the exposure time, and this shifts the benefit-risk ratio into the benefit direction.

Q: Should you also go outside right when you wake up to reset circadian rhythms?

A: It’s always good to be in contact with your natural lighting conditions (which are given by the sun), because they allow your organism to fully adjust to your environmental conditions. But it’s always a question of dose.

Q: I’ve heard that UV can’t get through certain locations. One physician told me that the bioplasma of NYC is not allowing me to get UV, or EMFs. What do you think can interact with UV to not allow the full benefit?

A: In big cities we have air pollution and smog conditions. This was the first signal that physicians got about 100 years ago when they found out in the cities children suffered from rickets. The reason was that the air pollution filters out the UVB. But you can easily find out if your area provides enough UVB. If people around you get a sunburn then you definitely have enough UVB coming through. But you shouldn’t go to this limit of course.


Q: Do you think non-native EMFs are harmful?

A : Study in Stockholm found connection between melanoma and electromagnetic fields. It was in the 1950s when the ultra short broadcasting system had been rolled out, and in these years you can find an increase in malignant melanoma mortality in these countries. In other countries where they did not roll out broadcast there was no change in malignant melanoma. This gives an idea that there might be a connection between electromagnetic fields.

Atmospherical windows: in these spectral regions our atmosphere is transparent and if there is higher solar activity you can expect another ground level of electromagnetic radiation coming from the sun which is not in the light part of the spectrum but in the electromagnetic part of the radio waves. The research has suggested that maybe there is another detection system in our organism which adjusts to electromagnetic activity levels and not only for the ultrashort wavelengths, but for the light activity and tolerance to the skin as well. If you can avoid non-natural EMFs this is a good idea.

Sun vs. UV blood irradiation


Q:  How much of someone’s blood will be eradiated with UV if they’re getting let’s say an hour of sun? There are treatments for UV blood irradiation. So how would this compare to someone just getting sun for about an hour?

A: What I can say is that when you are out in the sun the blood in your skin increases massively. Maybe 5 liters of blood go to the skin. This is the blood flow for one minute. If you’re sweating, if your body has to cool down under the influence of sunlight, it can be even more than 5 liters in one minute. But if you stay out for one hour-it’s several hundred liters of blood.

Q: So that would be equivalent to something like whole blood UV radiation or something like that?

A: This is hard to compare because with ultraviolet radiation you are using ultraviolet C at 204 nanometers. This is a wavelength which never will reach the capillaries in your skin, but you only radiate let’s say 1% of the blood you keep–so for example 50 ml will be radiated with ultraviolet C; so not easy to compare.

Q: Is this why sun can help people deal with infections? Let’s say you get an hour of sun in 3 days, you’re going to eradicate most of your blood over that period, and we know infections can’t really survive well with UV.

A: You have definitely shift immune activity, but the first goal your system needs to know, is if the inflammation is induced by bacteria, fungi, (etc.) or physical stimulus? So with influence of sunlight some immune cells will be depleted and deactivated, and others will be stimulated. So for chronic infections it is more stimulating the system as a whole in order to build it up to make a switch in your whole immune system, inducing a switch in your reaction forms. This is always a problem in chronic diseases–that the way your body deals with the problem is not adequate, so you have to switch the reaction pattern; and for that purpose it might be helpful/good for changing the reaction patterns.

Q: So we know that sun-UVA UVB is generally an immunosuppressant, but vitamin D is going to be something that increases the innate immune system, the active form of vitamin D, and then sun will also increase superoxide and free radicals which can directly combat infections. Is there any mechanism that stimulates the immune system to get rid of infections?

A: Vitamin D, the cathelicidins (stimulated by vitamin D)  are a class of molecules which help the organism to fight germs. So in a way our organism tries to find a workaround, also if the immune system is damaged in the short term by an overdosage of ultraviolet radiation. The workaround is an increased vitamin D production and increased cathelicidin concentrations also help against germs.

Vitamin D Supplements vs. Sun

Q: Vitamin D supplements vs. getting UVB. As far as the active form of Vitamin D goes we know that UVB will convert to an inactive form of D3 and that will convert into 1,25 dihydroxyvitamin D. Is the sun better at increasing the active form of vitamin D vs. vitamin D supplements, or does it not make a difference?

A:  This is subject to massive discussions in the scientific area. The specialists did not find a consensus. There are several ideas about it. If you ingest the 25 hydroxy vitamin D, then it will be transported not only by the D binding protein, but it will also be transported by lipoproteins. Compares it to standard mail vs. express mail. If you ingest vitamin D it will show a different distribution panel in your body because it’s not mainly bound to the D binding protein, but also to the standard lipoprotein molecules. This means that it might not reach the same cell types if it’s bound to one or the other.

Q: What if you overload the system, and give it a very high dose of vitamin D, wouldn’t it distribute to all of the tissues, because you’re going to overload the lipoproteins? Or is that something you would not recommend?

A: Maybe there is a very short while after a very high dosage but the question is if these high dosages are really recommendable. Sometimes able to reach dosages by oral supplementation they would never be able to reach by the natural pathway by sunlight. Have to even discuss if there is a dependence, for example with skin type. Maybe skin type 1 needs much less vitamin D than skin type 6. This would be logic under rules of evolution. This would explain the organism learning to deal and function optimally with high vitamin D levels. So it’s not applicable to people in Baltic or Norwegian ancestry, with red hair and skin type 1 for example (had to learn how to survive with minimal vitamin D dosage). Maybe in the future we will have to examine these as well.

Q: When you get vitamin D from the sun it’s sulfated vs. if you take it internally. Do you think that has an impact, or do we end up sulfating it anyway if we take it internally?

A: Didn’t find much information about these issues. What he knows, is there’s an influence in the sulfhydryl groups in proteins and from that aspect he can imagine that there’s something going on with the sulfur metabolism, but no clear idea about that.

Q: We absorb vitamin D through our skin, how do showers interact with this? How long do we need to keep the past ‘sun exposure’ on our skin in order to get enough D3 before wash it off with soap?

A: When we look at the dehydrocholesterol, which is the precursor molecule for the vitamin D production in the skin, it has the highest concentration in the area of the basal membrane of the skin. Normally you will not reach this by showering, but he thinks the habit of cleaning skin with detergents is bad, which change the lipid metabolism in the skin and make the skin thinner. We take fatty substances out of the skin using these detergents. Same with lotions-we don’t know how they interact in the deeper area of our skin. Depends on the frequency of taking a shower. If you take a shower just with plain water you will be fine; if you rub the skin and take off the cornea sites, this is a different story.

Sun & Carbs


Q: Sun makes me more tolerant to carbs. My guess is that it’s from nitric oxide, which can stimulate the wakefulness neurotransmitters in the brain. Do you have any take on that?

A: We know from Roman times in ancient Greece there was already the idea that the metabolism will be changed under the influence of sunlight. He thinks these examples are connected to the seasonal stress hormone-vitamin D as a seasonal stress hormone changes our metabolism in a way that we can perform better under the influence of sun during the summer (in the past). But today it’s a different. He doesn’t think we really have these characteristics of seasonal changes anymore because we changed our lifestyle significantly in this regard. The vitamin D as a steroid hormone definitely will have an influence on metabolism and this means tolerance for fat, lipids, carbs, and proteins.


Q: Is it better to get sun through a window or not get sun at all (i.e. people at work with windows)?

A: If it’s light coming through the window for general lighting purposes, then it’s much better compared to shielding and using artificial light sources. But the windows significantly change the spectral position of sunlight – many modern windows filter out infrared and many don’t filter out the UVA; so you will typically not get a sunburn behind the window. But still UVA radiation is there and you should avoid sitting directly behind the window for many years with this direct influence of sunlight on your skin.

Q: So would you try to put a cover that blocks UVA but lets the full spectrum in? (I have a red filter in the top part of my window to block out blue light at night).

A: He thinks we shouldn’t try to make heliotherapy or sunlight treatment when we are inside our ‘caves’ because you are in clothing, and when you sit in front of your computer, for example, and if you get direct sunlight even through the window pane this will probably induce an overdosage in the long term. He’s not sure about using the red filter. If you feel comfortable with it then it’s ok because it will take out the short wavelengths. But he prefers gray filter instead of always using the same color. This is because the colors themselves have particular potential to act as a photonic stimulus and if you would use the red filter one day, green filter the other, turquoise, (switching colors individually). you would get a kind of balanced exposition over time. If you always use the same color he’s not sure about long term effects.

Exposure Benefits


Q: As a guesstimate what % of the sun’s benefits is from vitamin D, infrared, UVB, UVA, color spectrum, color intensity, or other beneficial properties?

A: He thinks the sunlight was there from the very beginning and it was the task of the living organisms to deal with the sunlight. The sunlight consists of less than 8% of ultraviolet radiation, less than 5% infrared B radiation, and in between there is the visible part and the near infrared part- it’s the spectrum composition, a cocktail. It is beneficial for those that are adapted to it. For example if you are from Africa you will have different adaptation mechanisms. We really need good arguments to amplify certain parts, or to leave certain parts out. For example shorter wavelengths are stressful, and longer wavelengths are good for regeneration. In sunlight it’s in a good balance. It’s the full spectrum which makes sunlight so healthy, and if we change this, he is sure in the end it won’t turn out as a good idea.

Q: What is your guesstimate on how much of the benefits are from vitamin D?

A: Probably 10-20 % of benefits we can get from sunlight come from vitamin D. It’s a much bigger story. We need vitamin D but not everyone needs the same amount. People with red hair have a different type of melanin which increases amount of reactive oxygen species under the influence of sunlight so it’s very difficult to say. Can’t give the perfect recipe-this is what WHO or dermatologists do. They say to stay out of the sun because it’s harmful, but that’s too simple.

Q: You say we can’t replicate the full spectrum. The modern environment is taking out different parts of the sun than we have had in our evolutionary past (Australia with donut hole or pollution for example). Is this having a big impact or is it relatively minor?

A: When we are talking about benefits of sunlight we always have to talk about the location, elevation, height of the area we are living at-to make it simple, look at a particular country, Australia for example. The native population looks pretty different from the immigrants from England, which came to Australia many years ago, they also have increase incidences of skin cancer.

Q: So you think it has more to do with people not evolving in the same area rather than maybe ozone, or some environmental pollutant destroying the atmosphere in some way?

A: He doesn’t think we can guarantee that there was no ozone hole many years ago because in every eruption of a volcano some gases are released into the atmosphere which may deplete the ozone layer as well. There is, in Australia he thinks, elevated amounts of UVB radiation and this kind of proof will be very difficult. He looks at the people around the area-there must be a reason why they have darker skin.

Q: Can you explain why getting sun or UV is better at higher elevations?

A: You have the thinner atmospheric layer and UVB will come through much better. So the higher you are, the better—here you will get more UVB.

Q: If you’re lower and exposed to the sun longer, would it have the same health benefits?

A: If you are at the lower elevation then you would have to stay out longer (but in this case you would shift the ratio of UVB and UVA, so you can’t compare the two.)

Q: So you’re saying overall it would be healthier with regards to the sun, with living in higher elevations. But the higher you are the more hypoxia you have with lower oxygen concentrations. So do you think it would be more or less healthy overall, living at higher altitudes?

A:  People in the Alps for instance are very healthy. The have sailor skin sometimes-so can see there’s a higher impact of sunlight on the skin as long as they don’t over-clothe. He has a feeling people living at higher altitudes are quite healthy, but doesn’t have data to back this.

Sun, Fatigue, Nitric Oxide

Q: Why do some people get tired from the sun? My guess is that nitric oxide could cause fatigue in some ways. Or are there other mechanisms?

A: When he sunbathes he gets in a trance-like state/his system slows down. Nitric oxide might be one reason, but there’s a constant, intensified stimulus acting on the dermal nerve cells and sensory system so we know that if you increase neural stimuli on the eye (using blinking machines) or if you have loud auditory signals, then this puts you in a different state of consciousness. This is one very important aspect of sunlight, the state of conscious of being active in our eye and ear and sensory system, and shift into the dermal awareness.

Q: Nitric oxide can supposedly be both good and bad in the research-iNOS which is bad, and then there’s eNOS and nNOS which are generally good. The reason why I’m asking about nitric oxide is because I think UVA is something that’s increasing nitric oxide mainly, and I think it’s important to know when nitric oxide is good or bad in the body, how does that work?

A: It’s the same story with sodium chloride, or with water; it’s always question of the right dose. As long as there is nitric oxide signaling going on, as long as the dose is in the tolerance level of your organism, everything is fine. If you exceed, it will become harmful. Same with the reactive oxygen species as well (called janus-faced molecules). If you have too many of them it has negative consequences, or if you don’t have enough you will have negative consequences because it will have an impact on signaling.

Bright Light Sensitivity


Q: Why are some people sensitive to bright light (especially those with Chronic Fatigue)?

A: It’s not so easy to answer because of several possible explanations. For example if someone has a migraine, there is a common pathway between the light signal and the trapezius nerve, which can lead to overstimulation. It has to do with accommodation as well-so if someone is chronically sick this person will preferably stay inside and if you are not accommodated to bright intensities of light then it’s a difficult start; you have to do it step by step and with very small doses of exposure, increasing exposure time in small increment. It’s not easy to give general rules/explanations.


Q: What about people that have Lupus or other autoimmune conditions? And what would be your recommendations for those people?

A: We are at the point that not every person benefits from sunlight-some of them are pigmentosum patients, they can’t even stand artificial light from a certain intensity on, because they have missing repair mechanisms in their genes. Autoimmune system based disorders can make a patient susceptible to specific parts of the light spectrum for UV. Collagen disorders and autoimmune disorders to the collagen can lead to adverse reactions even from the longer wavelengths in the spectrum. For example, with red light or near infrared light the recommendation is that people should not trigger these adverse reactions, and if they can avoid it they should. It’s the same if someone has a history of skin cancer, it might be the best decision to avoid solar exposition.

Q: So if someone had skin cancer what’s the recommendation, should they stay away from sun or not?

A: You always have to evaluate the benefits vs. risks and if someone becomes very depressed by staying in the dark then it might be a good idea to get the right dosage of sunlight even after history of skin cancer. But it definitely depends. The risks are very different between different kinds of skin cancer. One positive thing is if someone develops basal cell carcinoma or squamous cell carcinoma-it is on the surface of the body so this is a type of disorder which can be detected and spotted in the early stage so you can treat it easily the earlier detected. But it’s mostly impossible to give a recommendation on a general level to someone who has very individual history of disease or disorder.


Q: Would you ever recommend sunscreen to somebody? Or recommend staying out of light. Or wearing a hat or a shirt?

A: Before I would recommend using sunscreen I would recommend to draw all the registers of textile and behavioral protection because sunscreen always interacts with our system. There is mineral-based sunscreen which only builds up a layer on the skin and then there are chemical sunscreens that are absorbed by the skin, entering the bloodstream, changing the concentration, and acting as endocrine disruptors-you can even detect them in breast milk. When you look it up in wikipedia in photo protection you can get an idea of the amount of additional oxygen species which are produced in the skin, these chemical sunscreens act as photosensitizers. So it depends, if you are stranded on a ship with no clothes you should use it to prevent severe sunburn. But his understanding is that the everyday strategy is to avoid solar overdosage.

Blue Light Protection Glasses


Q: There is a company called BluTech in the United States that sells glasses which take out a shade of blue from outside the UV spectrum. Some people recommend them because they say blue causes photooxidation of DHA in the eyes and that causes a bunch of problems with the circadian rhythm and other effects. And other people wear them because they have a bright light sensitivity. Do you suggest generally healthy people should be wearing these glasses, or should we just be getting the full spectrum of blue all the time that the sun has to offer?

A: Wouldn’t recommend using them in terms of protection from solar radiation. He thinks the gray filter is better because it doesn’t change the ratio between the different parts of the spectrum. He recommends to use blue light protection glasses- he developed some with a company in Germany. If you have light sources with an elevated amount of short wavelengths and missing long wavelengths in the red and near infrared region, then he thinks it’s a good idea to use blue light protection measures. With sunlight we have to ask ourselves why we have these non vision forming receptors which are sensitive to blue light. Why do we have them in our eyes? And his concept of explaining the  existence of this sensory system is that in nature there is a connection between blue light (can be seen and can be detected with these receptors) and ultra violet light (invisible). So if there is the risk for solar stress or UV hazard then this will be singled by an intensified content of blue. So if we are outside and we block out the blue or reduce blue using sunglasses, our system is not alarmed by this signaling pathway which uses the blue part of the spectrum. Sunglasses and blue blocking glasses reduce the visual alarming function of our eyes which lower our adaptation potential concerning for example the UV hazard.

Q: What about wearing regular glasses for myopia or things similar in the sun, because glasses will filter out certain spectrums. You say when you go outside you should try to minimize the amount of time you’re wearing glasses?

A: It depends on the filtering properties of the glasses. For example when he has an infrared camera, taking a picture from your face with the thermal camera, your eyes would look like black holes in the thermal picture. This means the correction glasses that person is wearing will definitely have an impact on the invisible parts in the long wavelength.  They on the other hand will have a filtering impact for shorter wavelengths than 400nm but it will change the radiation which reaches your eye which reaches the retina. For that reason for example if we reduce the near infrared part of the spectrum this might be a bad idea. When you filter parts out you can’t guarantee that the physiological reaction is the same.

Reproducing Light’s Benefits

Q: Some people don’t get sun for half of the year or even the whole year if people have office jobs. Is it better to use UVB lights? I also have lights with a spectrum of UVB and UVB, and a heat lamp that gives off infrared-should people be using these artificial lamps if they aren’t getting sun.

A: It depends on their individual needs. Some people really depend on sunlight and light, people who are drawn to tanning salons are in need of light. He thinks the majority of the population depends on light and needs the stimulus of light on our system. Those who feel like they are in need to more light they should get it….listen to your body.

Q: You mention that it’s important to have vitamin D levels pretty steady throughout the year, why is that so important?

A: We can think back 200 years or so seen in the Austrian or Swiss Alps where people live with their animals-exposed to sunlight during summer, and during winter the animals are in the stable and have less activity and much colder. If people are exposed to the seasonal climate conditions then it’s a good idea to have under-lighting changes of vitamin D supply, which means you have high levels during the summer and lower levels during wintertime. But we aren’t living in these conditions anymore.

Q: What’s the mechanism there? So you’re saying if the temperature fluctuates and it’s cold then we can go lower on vitamin D like our evolutionary ancestors, but what’s the mechanism by which cold will allow us to have less vitamin D, or if we don’t have it we’ll need steady levels?

A: He imagines that we have some molecular switches that vitamin D is the signaling molecule and it’s not only avoiding sunburn or building up vitamin D just for the bone structures or calcium metabolism, it is also changing the thermal regulation for example, adjusting the metabolism of water in your system, influencing the kidneys, influencing that you have enough water in your system for sweating so that you can cool down your body in case of overheating. Since we don’t have winter times in conditions as our ancestors, he thinks it’s better to have less darkness in winter because we have artificial light. The thermal regulation has shifted and we are sweating more in winter. We have a kind of summertime throughout the year in our environment, so we should have the vitamin D to go with it.

Circadian Rhythm


Q: As far as light at night, what intensity of light can disturb your circadian rhythm and if you just block out blue light is that enough for your circadian rhythm to function in a normal way? So as far as intensity and spectrum, what exactly do we need to do?

A:  Even tiny amounts of photons at the wrong time of the day can disrupt your circadian rhythm. If you reduce the amplitude of brightness during the day and darkness during the night this will have negative consequences to your circadian rhythms. Which means after the sun has set every kind of artificial light source will have potential to disturb circadian rhythms. Our system can cope with candlelight intensities quite easily because our ancestors had fire since hundred thousands of years, so we have a chance on evolutionary level to adapt. The moon will give you about 1 lux and when we live under natural conditions it’s always a good idea to have not only circadian rhythms but the lunar rhythms as well (the moonlight would give our ancestors the chance to stay awake during nighttimes for hunting, and in these times if you’re out for hunting during the night it’s a good idea to be a little more active compared to nights that are pitch dark). So there are not only the circadian rhythms, we have infradian rhythms and ultradian rhythms (which means the lunar cycle, the seasonal cycles). If you are living in a city like NYC it might be a better idea to shade the windows in a way that the stray light does not come in since stray light will have a stronger influence than sometimes maybe the moonlight when it comes through.

Q: I wear red glasses for 3 or so hours before I go to sleep-and they block out blue and green light, green light has some impact on the circadian rhythm (not nearly as much as blue), but would you say it’s better to get complete darkness rather than some kind of light, even though the blue and green is filtered out?

A: It won’t help you to use red glasses in the end if intensity of the light around you is high enough; you can still have melatonin suppression with red light. Every artificial light source after sunset will reduce your amount of melatonin which flows in your system, and it will reduce the regeneration time for the cone receptors in your retina. But it is not realistic to try to stay in pitch dark after sunset in our society. You can probably do better with amber glasses, because we are quite sure that the short wavelengths have much higher impact on melatonin suppression than longer wavelengths and avoiding green, with the red, you eliminate color vision completely, and with yellow or amber glasses you still have some discrimination between green, yellow, orange and red.

Q: So you recommend amber glasses over the red glasses, even though the red glasses can suppress melatonin. You need lower levels of green and even lower levels of blue, though you still recommend yellow glasses over red out of convenience?

A: It depends, if you feel you have a good feeling with the red glasses then go for it. But he thinks of more visual comfort in terms of discriminating the middle part of the spectrum up to the long wavelength part of the spectrum. If we had light in our evolutionary past, after sunset, it was higher and gives you the spectrum from green, turquoise, increasing up to the red, and it has a very low, short wavelength content, with fire you still can see green, lemon, yellow. In this way it would mimic the evolutionary past.

Q: Do you think that blue light on your skin can disrupt your circadian rhythms? So studies have initially found that they could, and then other studies haven’t been able to be replicated.

A: Difficult to experiment with colors on the skin because almost impossible to make double blind study with visible colors. Second problem is the more you measure, the more mistakes can occur. Not possible to reproduce. We know for example that blue light application can influence the pain level because it helps body produce nitric oxide and this is just an effect which goes through the tissue through the skin and dermal layers and so he knows there are effects from his own experience that color on the skin can definitely have an effect. But he’s not sure about the effect on the circadian rhythm. It’s hard to have a trial.

Q: Is the f.lux program (if you put it on the setting that gives off the lowest setting of light) enough to throw of your circadian rhythm?

A: He made some spectrum measurements with f.lux and he thinks it’s a neat strategy to reduce blue, but the ratio between the red and the blue is still 1 to 10 or so, so you cannot fully eliminate the blue content. This is because f.lux will not eliminate the intensity of the blue LEDs in the backlighting system of your screen. It will not reach full contrast ratio with TFT screens, for that reason it’s not possible by software means to eliminate the blue in the spectrum of your screen.

(ME): I use the f.lux and glasses but sometimes I wonder if f.lux is enough, but I guess it’s not!




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  • Kathleen Maddox

    I wanted to ask a question about the lightbulb safety , i at least heard from a article fron dr wunsch that incandesent bulbs are safest for eyes but i like the coated frosted one in my caldlabra bulbs ,they are not so much glare .can the coated bulbs cause harmful light to the eyes ? Thanks

  • Sam

    Hi Joe,
    I researched EMF a bit and there are a lot of companies that sell products that claim to block emf. The fact if that you really can’t block all of it (unless you wear that cover in a doctor’s office just before you do x-rays), only reduce it and that matter to what degree. You really need a meter to make sure the fabric reduces a good amount of EMF. Do you know/did you measure effectiveness of these fabrics ? Any one stand out ?

  • Sam

    hello Joseph,

    That Pocket Miracle is not for sale in the States. how would one purchase it ? Traveling to Canada/Mexico is a bit too far for me, plus one should consider the border crossing.

  • Ilian Andreev

    Every prescription eyeglasses have UVA and UVB protection. Is this bad for your health and for your circadian rhythm?

    1. Joseph M. Cohen

      Can’t say for sure, but I try to take glasses off

  • marie

    What’s your view on ultraviolet blood irradiation IVs? I thought he was alluding to it but I see no notes

  • re

    a little confused by this as it seems you guys went back and forth on this a bit and his responses seemed different than what you (and me) previously had believed.

    About timing and types of UV: To set it straight, I know overall he recommends a full spectrum but to clarify

    UVA is bad or good (i thought UVA were the bad rays)?

    UVB is bad or good (before I had thought UVB were the “good rays”?

    So the recommendation now is the optimal time to get sun exposure is at noon for the good rays? (Before I had thought that was the worst time due to more harmful rays creating sunburn)

    When would be the best time for Circadian Rhythm? Still the morning or is that noon now as well?

    So then when is the worst time for Sun exposure?

    Is tanning your skin (without burning) good? Like would stopping right before or right as you start to get that sensitive “redness” he mentions be a good indicator of the proper amount of exposure?

    Was hoping to get some clarity haha =) thank you very interesting interview!

    1. re

      a little confused by this as it seems you guys went back and forth on this a bit and his responses seemed different than what you (and me) previously had believed.

      About timing and types of UV: To set it straight, I know overall he recommends a full spectrum but to clarify

      UVA is bad or good (i thought UVA were the bad rays)?

      UVB is bad or good (before I had thought UVB were the “good rays”?

      So the recommendation now is the optimal time to get sun exposure is at noon for the good rays? (Before I had thought that was the worst time due to more harmful rays creating sunburn)

      When would be the best time for Circadian Rhythm? Still the morning or is that noon now as well?

      So then when is the worst time for Sun exposure?

      Is tanning your skin (without burning) good? Like would stopping right before or right as you start to get that sensitive “redness” he mentions be a good indicator of the proper amount of exposure?

      Was hoping to get some clarity haha =) thank you very interesting interview!

      1. Joseph M. Cohen

        -Both UVA and UVB are good in proper doses.

        -Noon sun has the most UVB.

        -If you get burned or close to it, you got too much sun.

        -For circadian rhythm, you want to get AM Sun and sun throughout the rest of the day.

  • Lexar Flash

    Would you recommend light boxes for seasonal affective disorder or if you don’t get daily access to the sun ? Is the treatment more effective than placebo?

    1. Joseph M. Cohen


  • Denvill

    Hi! I just want to make sure that I understand Joe- would you recommend putting orange sunglasses ontop of red glasses every night?

    1. Joseph M. Cohen


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