Sunlight Reduces the Risk of Death!

By: Marc Sorenson, EdD Sunlight Institute


Many years ago, I read of ongoing research by Dr. Pelle Lindqvist—reasearch indicating that greater exposure to sunlight resulted in longer life. I made several attempts to contact Dr. Lindqvist, but was unsuccessful. However, one of his colleagues answered my query and informed me that the research would not be completed later on and then be published. The results are now available, and they are impressive.[1]

During a 20-year period, the subjects in the study who avoided sun exposure were twice as likely to die of any cause compared to those who had the highest sun exposure, and the researchers made this statement: “In both models the summary sun exposure variables showed a ‘dose-dependent’ inverse relation between sun exposure and all-cause death.”

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Sanitizing with Sunlight: the Best Disinfectant

By: Marc Sorenson, Sunlight Institute


Is sunlight the best disinfectant? Through serendipity, I happened on an article called Natural Alternatives to Bleach for Disinfecting.[1] It discussed pros and cons of such disinfectants as bleach, vinegar, hydrogen peroxide and yes, sunlight. The article stated that bleach could be dangerous, causing irritation to the eyes, mouth, lungs and skin, and when mixed with ammonia could result in the release of toxic fumes.

The authors suggested three alternatives: vinegar, which is non-toxic, hydrogen peroxide, which can cause burns at high concentrations, but when used safely is reasonably safe, and sunlight, which like vinegar is nontoxic. The article states “In fact, scientists have found that exposing a bottle of water to sunlight for 6 hours is an economical way to provide developing countries with safe drinking water (see References 2). The disinfecting properties of sunlight can also be useful around the house. If you have an object that you can move outside, the sun’s rays can help disinfect it. A stained piece of white laundry can be effectively brightened and disinfected by spraying the stain with lemon juice or vinegar and then hanging it in the sun.”

Imagine that—no wonder my mother hung her clothes out on a line in the summer sun to dry, although I don’t recall any use of vinegar or lemon juice.

The mention of water also took me back a few years to the time I spent a week with a Mexican friend of mine in a small town near Guadalajara called Juchipila. As most of you know, the drinking water in Mexico is often contaminated with noxious bacteria, and the sale of bottled water to prevent “Montezuma’s revenge” is big business. While there, my friend Miguel and I visited a bottled-water plant. Interestingly, the only method of purification was the exposure of the water to ultraviolet light. It obviously did a terrific job, because the proprietor did a good business with no reported problems of related bacterial diseases.

There was a time when sunlight was used to disinfect hospitals, and such should be the case now, considering the superbugs that have developed a resistance to antibiotics. The legendary humanitarian Florence Nightingale observed that sunlight helped heal wounded soldiers and insisted that hospitals be constructed to allow the free entry of sunlight.[2]

In reality, it has long been known that sunlight is a powerful disinfectant and bactericide. As early as 1877, researchers discovered that sugar water left in the shade became cloudy, indicative of bacterial growth, but if exposed to sunlight, it remained clear.[3]  In 1890, the German microbiologist Robert Koch (who had isolated and described the tuberculosis bacterium in 1882), showed that sunlight killed TB bacteria.[4] Later on, research showed sunlight also killed E. coli bacteria in twelve feet of seawater and in waste stabilization ponds.[5] [6] [7]

In the aforementioned article comparing alternative disinfectants with bleach, the authors mentioned that exposing the armpits to sunlight would kill the bacteria that caused odor. There is little that I enjoy more than sunbathing with my hands behind my head and my armpits exposed to the sun. Lots of vitamin D, nitric oxide and endorphins produced, and later on I am more popular with my friends!

Sunlight exposure has been shown to heal Tuberculosis, psoriasis and a host of other diseases. To protect against a multitude of diseases, infectious and otherwise, be sure that you and your environment are exposed to plenty of sunlight,  but also be sure not to burn. Any reddening of the skin indicates that you have had enough.



[2] Nightingale, F.  Notes on Hospitals (third edition) Longman, Roberts and Green 1863.

[3] Downes, A.  Researches on the effect of light upon bacteria and other organisms. Proc Roy Soc Med 1877;26:488.

[4] Hobday, R. The Healing sun. Findhorn Press 1999:132.

[5] Hart, D.  Sterilization of the air in the operating room by special antibacterial radiant energy.  J Thorac Cardiovasc Surg 1936;6:45.

[6] Gameson, A. et al. Field studies on effect of daylight on mortality of coliform bacteria.  Water Res 1967;1:279.70.

[7] Calkins, J. et al.  The role of solar ultraviolet radiation in natural water purification.  Photochem Photobiol 1976;24:49.

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Morning Sunlight May Lead to a Slimmer Figure.

By: Marc Sorenson, EdD Sunlight Institute 

 Chalk up one more benefit of sunlight—morning sunlight that is. A recent study from Northwestern Medicine demonstrates that timing and intensity of light correlate with body mass index (BMI).[1] BMI is a numerical computation that compares height and weight, and it is considered a good measurement to assess obesity or the lack thereof. A high BMI usually means that a person is obese or at least approaching obesity. Optimal BMI is 18-25. Below 18 is underweight, above 25 is overweight, 30 is obese and 40 and above is morbidly obese.This research showed that exposure to bright morning light was directly related to BMI. After adjusting for confounders such as diet, exercise and sleep timing, it was determined that very early exposure to morning light correlated remarkably to lower BMI; even when light intensity was equal at different times of the day, those who received earliest bright light had lower BMI. In fact, for each hour later in the day that the light exposure occurred, BMI increased by 1.28 units. This fact is exceptionally important, since a person who has a BMI of 25 (upper ideal range) could approach 30, or obesity, simply by the habit of sunlight exposure later in the day, i.e. 10:00 AM rather than 6:00 AM.The authors of this research suggested that the mechanisms involved in weight control by early light exposure could be the following: (1) resetting the circadian rhythm (internal clock), (2) the greater amount of blue light in morning sunlight and (3) effects on melatonin production. Whatever the reasons, we now know that early-morning sunlight is important to weight control. It may also be important to other health issues.Since we know that the greatest vitamin D production, as a result of sunlight exposure, occurs around noon, I would suggest enjoying some early sunlight to begin the day, and then to engage in moderate, non-burning sunbathing around midday to optimize vitamin D levels. That should produce the greatest benefits possible.


[1] Reid KJ, Santostasi G, Baron KG, Wilson J, Kang J, Zee PC. Timing and intensity of light correlate with body weight in adults. PLoS One. 2014 Apr 2;9(4)

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Working in Natural Light Improves Mood, Performance, Behavior and Psychological Health.

By Marc Sorenson, EdD.  Sunlight Institute

There are few things that improve our wellbeing like arising early in the morning and walking outside on a bright, sunny day. Our attitude improves, our serotonin and endorphin levels increase and there is an almost immediate feeling of exhilaration. We also become less confrontational, and our minds seem to click on all cylinders. Later on, around midday, if we are fortunate enough to have time to safely sunbathe (with lots of skin exposed), we produce large quantities of vitamin D, and our nitric oxide levels increase. This gives us a delicious feeling of relaxation and an almost instantaneous lowering of blood pressure as the cares of the day melt away.

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Sleep Quality is improved by Exposure to Nature and Sunlight.

By Marc Sorenson, EdD, Sunlight Institute

A good, sound sleep is important to human health, both physical and mental. According to Dr. Diana Grigsby-Toussaint, “Studies show that inadequate sleep is associated with declines in mental and physical health, reduced cognitive function, and increased obesity.” She and her colleagues at the University of Illinois recently published a new study demonstrating that a natural environment may help people get the sleep they need.[1] The study showed that exposure to nature, which they dubbed “greenspace,” was associated with a more restful sleep. Other surroundings such as a sandy beach with an ocean view were also conducive to better sleep. One of the measurements used to qualify an area as greenspace was the availability of sunlight.[2]

I can attest to the fact that when I regularly walk through the pines and aspens located in the high mountains near my Nevada ranch, I sleep better at night. When I don’t get enough outdoor time in the trees and sunlight, I begin to suffer from what my friend, Dr. William Grant, calls nature-deficit disorder, or NDD. My whole mood is altered, and not for the better. Dr. Grant is not only a great sunlight scientist, but an avid birdwatcher, which takes him out daily do get his dose of nature.

We have a primal need for sunlight and natural surroundings, and too many city dwellers do not connect with sunlight and nature. Don’t fall into that trap. There is an adage that says, “What gets scheduled gets done.” Plan to be outside as often as possible and soak up some sun when it is available. Natural surroundings with sunlight are better than any psychiatrist or physician for maintaining mental and physical health.

[1] Grigsby-Toussaint DS, Turi KN, Krupa M, Williams NJ, Pandi-Perumal SR, Jean-Louis G. Sleep insufficiency and the natural environment: Results from the US Behavioral Risk Factor Surveillance System survey. Prev Med. 2015 Sep;78:78-84.


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Anxious? Try a Little Sunlight.

By Marc Sorenson, EdD, Sunlight Institute

Are you suffering from anxiety disorder, but fear taking drugs?  Your fear is well-founded. It has been shown that a class of drugs called anti-anxiety drugs, i.e. valium and Xanax, and sleep aids like Ambien, Sonata and Lunesta lead to increased risk of death.[i] During 7.6 years, and after controlling for other factors such as sleep disorders, anxiety disorders and other psychiatric illnesses, it was found that the risk of dying was 3.46 times higher in those who took the drugs compared to those who did not. Considering the material we have posted on this site regarding brain disorders, insomnia, and sunlight, it seems reasonable to believe that a better and less dangerous anxiety-treatment option would be regular sunlight exposure.

Research from Denmark has shown that morning light, made to mimic daylight, relieves anxiety by reducing the activity of the brain’s fear center.[ii] The efficacy of the light treatment was based on the intensity of the light: the greater intensity, the greater the effect.

Another scientist, Dr Klaus Martiny, commented on the above study and noted that morning light improves sleep. “A lack of daylight disrupts some hormonal processes in our body that regulate our circadian rhythm. This can result in a shift in circadian rhythm, so that people go to sleep later and later in the evenings, and this shift is associated with an increased risk of depression.”[iii]

Martiny suggested that a good rule of thumb is to go to sleep before midnight and awaken before 8:00 AM. However, we discussed in the post on obesity that the earliest morning sunlight was associated with a remarkably lessened risk of obesity, which was also attributed to resetting the circadian rhythm. We therefore suggest that a better rule of thumb is to be outside for a half-hour when the sun rises each morning.

Get your morning sunlight, your midday sunlight and your afternoon sunlight. Sunlight is the great healer.

[i] Weich S, Pearce H, Croft P, Singh S, Crome L. et al. Effect of anxiolytic and hypnotic drug prescriptions on mortality hazards: retrospective cohort study. BMJ 2014;348:g1996.

[ii] Christensen B. Morning light relieves anxiety. Science Nordic 2014. Accessed August 8, 2015.

[iii] Accessed August 8, 2015

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Understanding Proper Circadian Rhythms and the Critical Importance of Light in maintaining them.

By Marc Sorenson, EdD, Sunlight Institute

Sunlight, through regulation of the proper circadian rhythms, influences the health of nearly the entire the human body.

Circadian rhythms are variations in physiology and behavior that persist with a cycle length close to, but not exactly, 24 hours. It is necessary to synchronize the rhythms on a regular basis to maintain them, and such synchronization is achieved through regular exposure to light and darkness.[i] This is also known as “resetting the biological clock.”

Circadian rhythms include sleeping and waking in animals, flower closing and opening in angiosperms, and tissue growth and differentiation in fungi.[ii] There are other factors besides light and darkness that have an influence on either synchronization or desynchronization of the clock, but they play a small part. For the purpose of this book, we will consider the influence of light in maintaining proper circadian rhythms, and by so doing, enhance human health.  Researchers have stated that “Mammalian circadian rhythms form an integral physiological system allowing for the synchronization of all metabolic processes [emphasis mine] to daily light/dark cycles, thereby optimizing their efficacy.”[iii] Anything that has a profound effect on all metabolic processes is obviously important to the proper functioning of the human organism.

When circadian rhythms are disrupted (or de-synchronized), it upsets the physiology of the human body. People who take long flights across many time zones often feel “out of sorts” and many have a difficult time in adjusting to time zones to which they are not accustomed. We call this “jet lag,” and it is a common manifestation of a desynchronized rhythm. Another is night-shift work. When the body is expecting bright light and instead is exposed to dimness or darkness, its attempts to resynchronize can cause cloudy thinking, fatigue, and even more destructive damage to the psyche and physiology.

There are innumerable research papers that demonstrate the health detriments of a desynchronized circadian rhythm. For example, research on rats shows that desynchronization leads to premature cellular aging,[iv] as measured by telomere length (a DNA marker for life span); the shorter the telomeres, the shorter the life span. Young rats that were “jet-lagged” had aging characteristics of middle-aged rats.

It also appears that circadian disruptions change the structure of important proteins that play a protective role in cancer, thereby increasing the risk of breast cancer.[v] Other research has demonstrated that disruption of circadian rhythms may lead to a profound increase in the risk of heart disease, metabolic syndrome and other cancers;[vi] [vii] even the risk of poor dental hygiene and dental caries may be increased by desynchronized circadian rhythms.[viii]

One might ask why I am making such an emphasis on circadian rhythms. Here is the answer: Sunlight can, and should, reset the circadian clock daily; it is the timing cue, also called a zeitgeber, which entrains the physiologies of humans and thereby helps to prevent critical illness.[ix] [x]

This is another positive benefit of sunlight that occurs apart from vitamin D production.

[i] Duffy J, Cziesler C, Effect of Light on Human Circadian Physiology. Sleep Med Clin. 2009 June; 4(2): 165–177.


[iii] Mitchell MI, Engelbrecht AM. Circadian Rhythms and Breast Cancer: The Role of Per2 in Doxorubicin-Induced Cell Death. J Toxicol. 2015;2015:392360.

[iv] Grosbellet E, Zahn S, Arrivé M, Dumont S, Gourmelen S, Pévet P, Challet E, Criscuolo F. Circadian desynchronization triggers premature cellular aging in a diurnal rodent. FASEB J. 2015 Aug 10. pii: fj.14-266817. [Epub ahead of print]

[v] Mitchell MI, Engelbrecht AM. Circadian Rhythms and Breast Cancer: The Role of Per2 in Doxorubicin-Induced Cell Death. J Toxicol. 2015;2015:392360.

[vi] Vignesh Shanmugam, Amro Wafi, Nawaf Al-Taweel and Dietrich Büsselberg. Disruptions of circadian rhythm

Increase the risk of cancer, metabolic syndrome and cardiovascular disease.  Journal of Local and Global Health Science, 2013:3.

[vii] Bratsun DA, Merkuriev DV, Zakharov AP, Pismen LM. Multiscale modeling of tumor growth induced by circadian rhythm disruption in epithelial tissue. J Biol Phys. 2015 Aug 21. [Epub ahead of print]

[viii] Lundgren AM, Öhrn K, Jönsson B. Do adolescents who are night owls have a higher risk of dental caries? – a case-control study. Int J Dent Hyg. 2015 Jul 22. doi: 10.1111/idh.12165. [Epub ahead of print]

[ix] Remi J. Humans Entrain to Sunlight – Impact of Social Jet Lag on Disease and Implications for Critical Illness. Curr Pharm Des. 2015;21(24):3431-7.

[x] Hasegawa Y, Arita M. Circadian clocks optimally adapt to sunlight for reliable synchronization. J R Soc Interface. 2013 Dec 18;11(92):20131018

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Sunlight, UVA and nitric oxide. Another answer to covid?

Sunlight, UVA and nitric oxide. Another answer to covid?

Sunlight and UVA reduce Covid-19

Sunlight is indeed another answer to profoundly reducing the risk of Covid. By Marc Sorenson, EdD.

Sunlight is associated, with lower illness and death from the Covid-19 virus.

So says new research from the British Journal of Dermatology. I opine that this research is of epochal importance, and it is something I postulated a year ago. At that time, certain people mocked and belittled me. It seems like the “experts” of the world had a laser focus on producing a vaccine. Thus, they denigrated anything or anyone who did not follow their dictatorial rules. Consequently, I was gratified when this research appeared.

First of all, for the purposes of the Journal research into sunlight, the investigators assessed deaths from covid-19 at the county level across the USA. They then replicated the measurements in England and Italy. The researchers then measured the amount of sunlight in each county in Kilojoules, a unit of heat equal to .239 calories.

Furthermore, after measuring the sunlight and death from Covid-19, they adjusted their data for demographic, socioeconomic and environmental variables.

This part of the sunlight research is especially relevant:

“Only areas where UVB was too low to be inducing significant cutaneous vitamin D3 synthesis were modelled.” This took vitamin D out of the equation.

UVB light stimulates vitamin D production when it makes contact with the skin. Therefore, ensuring no vitamin D production (by eliminating UVB light), they eliminated a potential misconception. There was no way vitamin D could be the mechanism of action to decrease Covid-19. Thus, one might say that this was was a pure sunlight study, and the idea to eliminate vitamin D was pure genius.

Indonesians fighting coronavirus in the sunlighto

Too many people believe that if sunlight exposure has a positive effect, the mechanism must be through vitamin D. This research corrects that theory.

So what is the mechanism, if it is not vitamin D? The answer is nitric oxide (NO). Sunlight  exposure also produces NO in the skin. Yet, NO occurs in skin after exposure to UVA rays, not the vitamin D-producing UVB. In addition, NO has the ability to stop the replication of the Covid virus. One of the beauties of this system is that UVA rays and NO are available at any season when the sun is shining. This indicates that this healing action of sunlight is also available year-around.

The results:

Protect the children with sunlight

The mortality risk ratio (death risk ratio) due to Covid-19, over the three countries, estimated a decline of 32% for each increase in 100 kilojoules per meter2. Thus, as sunlight intensity increased, death from Covid-19 decreased concomitantly. It seems like a great idea to increase exposure to non-burning sunlight among all areas where Covid-19 exists.

Certainly, the lockdown was a great detriment to human health.

For more information on sunlight and health, visit and read the book, Embrace the Sun.

Happy Sunning!Embrace the Sun for health

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Indoor living, lack of sunlight, melanoma

Indoor living: What is the cost in sunlight? By Marc Sorenson, EdD.

Indoor living is potentially debilitating because it creates an unnatural environment, especially when carried to extremes. It pollutes our surroundings, and because it places us in an abnormal ambience, robs us of our natural existence. Now, no one should suggest that I want the populace to be outside 24 hours per day. Nevertheless, it seems like we are relentlessly pursuing the opposite—a world of 24 hours per day inside. In the last few decades, we have moved indoors from a mostly agrarian society. Thus, we have lost our hard physical labor, our contact with the earth, and our fresh air. Another vital loss has been the loss of sunlight, our greatest healer.

So just how much time do we spend in indoor living? The National Human Activity Pattern Survey (NHAPS) summed it up quite well with the use of a chart.          


One gleans from the chart that we spend 87% of our time indoors, plus another 6% inside a car. That is almost no outdoor living at all!

To an extent, we engage in indoor living because we fear the sunlight, and especially melanoma.

Considering the chart data, it makes one wonder why we fear the sunlight so much. Yet, the media constantly bombards us with messages to avoid sunlight and further endanger ourselves by slathering ourselves with sunscreens. Sunscreens, of course, are another method to reduce the minuscule quantity of sunlight available to our sedentary, indoor lives. That sunlight might otherwise find its way to the skin and save our lives.

Sunlight and health for all

Fear of melanoma is one major factor that has driven us to indoor living and poor health.

The Melanoma International Foundation stated that melanoma has increased alarmingly since 1935. They show that in that year, approximately one in 1500 people had a melanoma diagnosis. They then said that people had 30 times the risk of melanoma in 2010-2014 as they did in 1935 and blamed the increase on increasing sun exposure after 1935. Nevertheless, as melanoma increased, sun exposure decreased by about 90%! Most agrarian and other outdoor jobs nearly disappeared. For a full analysis of this counterintuitive message from the dermatologists, read the book, Embrace the Sun.

One might think that since indoor living increased so profoundly, melanoma should also decrease profoundly.

Here is another chart that I prepared for Embrace the Sun. It shows the spectacular increase in melanoma that accompanied the remarkable decrease in sun exposure.

less sunlight, more melanoma

For robust health, we must eschew a life of nearly total indoor living and return to the natural, outdoor lifestyle. We must also obtain some regular, non-burning sunlight without sunscreen.

For more about the myriad benefits of sunlight on health, visit Sunlight Institute and read the book, Embrace the Sun. Remember to avoid sunburns.


Indoor living holds no attraction for this girl.

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Senior citizens obtain vitamin D from sunshine.

Senior citizens obtain plenty of vitamin D from sunlight. By Marc Sorenson, EdD

Senior citizens, sunlight, vitamin D

Senior citizens, and middle-aged citizens, according to some experts, cannot produce as much vitamin D from sun exposure as young people. Thus, to prevent vitamin D deficiency, medical professionals may recommend vitamin D supplementation to make up the gap. Nevertheless, I know first-hand there is no problem for senior citizens to optimize vitamin D levels by using sun, sans supplementation. I mentioned in a recent blog that one of my friends, Wayne, was able to achieve a level of over 100 ng/ml. This was spectacular, since an optimal level is 60-80 ng/ml. Wayne achieved his vitamin D levels due to spending much of his daily time sunbathing. Consequently, I was surprised at his result, and so was his physician, who told him to stop taking supplements immediately.

The doctor likely did not know senior citizens could achieve elevated vitamin D levels while sunbathing. He probably thought that Wayne’s results were impossible.

Sunlight for seniors

The doctor was amazed when Wayne told him he had never taken a D supplement and used sunlight only. While production of vitamin D in human skin decreases with age, it does not decrease to zero. In addition, Wayne was living proof that what senior citizens need is more sun exposure. Wayne was in his seventies. Thus, the extra sun exposure balances any decrease of vitamin D production due to age. Hence, it simply takes a bit longer for higher levels to result.

New, corroborating evidence confirms the efficacy of sunlight for senior citizens.

A recent study confirms sunlight is almost as effective for seniors as younger people, for vitamin D production. The study measured the response of vitamin D metabolites after a 30-minute bout of sun exposure. First of all, the investigators exposed the subjects to 30 minutes of sunlight at solar noon. In addition, the exposure was broken up into 15 minutes each on the ventral and dorsal sides of their bodies. The subjects included 30 healthy individuals. They divided into two groups according to age. Eighteen of them were 20-37 years old and 12 of them were 51 to 69 years old. The researchers assessed serum vitamin D levels at baseline and 72 hours after the sun exposure. They also assessed the older group again after 168 hours.

A synopsis of the results and conclusions

After sun exposure of 72 hours, vitamin D increased in both younger and older groups. Yet, the increase was greater in the younger group. Furthermore, Vitamin D production decreased by 13% per decade of age. In conclusion: “Serum D3 concentration increased significantly in response to outdoor sun exposure in younger and older adults. While ageing may dampen cutaneous synthesis, sunlight exposure is still a significant source of vitamin D3.”

This research, and the remarkable results of my friend Wayne, indicate that all ages can effectively use sunlight. Sunlight will stimulate the production of a bounteous harvest of vitamin D by the skin. Furthermore, the sun’s rays will produce another bounteous harvest of health benefits that have nothing to do with vitamin D. A pill will never achieve these benefits.

For more information regarding the effects of sunlight on health, visit and read the book, Embrace the Sun.

Happy Sunning! Sunlight inhibits vitamin D deficiency

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Alzheimer’sBDNFblood pressurebonebreast cancercancercircadian rhythmCovid-19deathdepressiondiabetesendorphinhealthheart diseaseHypertensioninflammationkidsmelanomametabolic syndromemoodMSmultiple sclerosismyopianitric oxideobesityosteoporosispregnancyprostate cancerpsoriasisserotoninskin cancerStrokesunsunburnsun exposuresunlightSunlight exposuresunscreensunshinetanning bedsUVUVAUVBvitamin dvitamin D deficiency