Tag Archives: circadian rhythm

Sun Exposure is directly associated with Cognitive (mental) Ability.

Sun and cognitive ability by Marc Sorenson, EdD, Sunlight Institute…

If you have depression, you may also have cognitive impairment, according to older research that I just became aware of. The researchers measured cognitive abilities among approximately 14,000 depressed subjects and then exposed them to either one day of sunlight or two weeks of sunlight. They then determined if cognitive disabilities were associated with the sun they obtained.[1]

The results were impressive: Those who were sun-deprived for two weeks had 2.5 times the risk of being cognitively impaired, compared to those who had sufficient sunlight. A one-day exposure made no significant difference in cognition.

Results of other research, based on a 15-year residential history of varying degrees of sun exposure, has also shown that cognitive impairment in persons who were below the median exposure to sun, was 88% greater than those who were above the median.[2] The researchers mentioned vitamin D as a possible mechanism by which sun positively influenced cognition, but they also remarked that regulation of the circadian rhythm by sunlight could be a factor.

Several other studies showed a close, positive association between vitamin D levels and cognition, and as we know, vitamin D levels in most cases are a surrogate measurement for sun exposure.

The message is to get plenty of sunlight to improve mental clarity. Happy thinking!

[1] Shia T Kent, Leslie A McClure, William L Crosson, Donna K Arnett, Virginia G Wadley and Nalini Sathiakumar. Effect of sunlight exposure on cognitive function among depressed and non-depressed participants: a REGARDS cross-sectional study. Environmental Health 2009, 8:34

[2] Kent ST, Kabagambe EK, Wadley VG, Howard VJ, Crosson WL, Al-Hamdan MZ, Judd SE, Peace F, McClure LA. The relationship between long-term sun radiation and cognitive decline in the REGARDS cohort study. Int J Biometeorol. 2014 Apr;58(3):361-70.

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More Truth about Sun Exposure

By Marc Sorenson, EdD… Sun exposure benefits…

A very important paper regarding the necessity for sun exposure has recently been published by the journal Medical Hypothesis.[1] It is entitled Regular sun exposure benefits health, and it discusses the pros and cons of sun exposure. One of the salient statements in the paper is that intermittent sun exposure may increase the risk of skin cancer, whereas regular exposure to sunlight might benefit health. For those of us who have for years studied the beneficial effects of sun exposure, the use of the word “might” is the only drawback to the statement. There is no doubt that for the majority of the population, regular sun exposure absolutely protects and enhances health.

Among the diseases mentioned as being reduced or prevented by regular sun exposure are the following:

  1. Cancers: Colon, breast, prostate and non-Hodgkin lymphoma
  2. Multiple sclerosis
  3. Hypertension
  4. Diabetes

As the authors mention, most of these positive effects of sun exposure were previously ascribed to Vitamin D, but they point out that immune system function is enhanced by sun exposure beyond the effects of vitamin D, and list other non-vitamin D benefits of the sun, including:

  1. Production of nitric oxide
  2. Production of melatonin
  3. Production of serotonin
  4. Regulation of the circadian clock

I have discussed most of these items on the Sunlight Institute web site, but it was good to see new research that, in particular, separated the health benefits of sun exposure from vitamin D production. The idea that has become popularized during the past decade, that all benefits of sun exposure come from increased vitamin D production, is simply not true and can lead to the supplementation of vitamin D as a “cure” for diseases that may not be influenced by that hormone.

Of course, vitamin D is an exceptionally important photoproduct, and the only natural way to attain it is by exposure to the sun or to other sources of UVB light (such as a sunlamp or a tanning bed). The beauty of using these sources, rather than a vitamin-D capsule, is that all of the benefits of nitric oxide, melatonin, serotonin and circadian entrainment are included in the package.

Safely enjoy the sun, and you then will also safely enjoy better health. Remember not to burn, and to gradually develop a good tan.

[1]  van der Rhee H, de Vries, E, Coebergh, J. Regular sun exposure benefits health. Medical Hypotheses 97 (2016) 34–37

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Sun Exposure reduces Obesity; Vitamin D does not.

By Marc Sorenson, EdD. Sunlight Institute…

Sun exposure reduces the risk of obesity, and that relationship has been credited to vitamin D. However, one study, conducted on mice, shows that vitamin D may have nothing to do with reducing or preventing obesity.[1] The animals were placed on a high-fat diet to cause obesity. Then they were subjected to long-term exposure to ultraviolet radiation (UVR), (which is the same sunlight spectrum that leads to the production of vitamin D and other photoproducts). The UVR significantly suppressed weight gain and other measures of the metabolic syndrome (MetS), including glucose intolerance, insulin resistance, fasting insulin levels, fatty liver disease and serum cholesterol levels.

Interestingly, when the animals were supplemented with vitamin D, no such benefits occurred, meaning that UVR created the positive protections independently. However when nitric oxide was applied to the skin of the animals, the positive effects on weight loss and metabolic syndrome were again observed. Nitric oxide, of course, is another photoproduct of sun exposure, which has many positive health effects.

Other research showed that early-morning sun exposure was correlated to lower body-mass index (BMI) which is a measure of body fatness.[2] The authors of that 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 quantity of blue light in morning sun and (3) effects on melatonin production. Whatever the mechanisms, we now know that early-morning sun is important to weight control. It may also be important to other health issues. But before we begin to think that sun exposure is the cure-all for obesity, realize that poor nutritional habits and lack of exercise are much more important. Nevertheless, sun exposure can furnish one more arrow in the quiver of protection from obesity.

Get your sun exposure and stay slim! Be careful not to burn.

[1] Geldenhuys S, Hart PH, Endersby R, Jacoby P, Feelisch M, Weller RB, Matthews V, Gorman S. Ultraviolet radiation suppresses obesity and symptoms of metabolic syndrome independently of vitamin D in mice fed a high-fat diet. Diabetes. 2014 Nov;63(11):3759-69.

[2] 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;2;9(4)

 

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Chinese Research states that Elderly People need more Sun Exposure!

By Marc Sorenson, EdD. Sunlight Institute… Sun exposure.

New research from China suggests that sun exposure, through vitamin D production, contributes improvements in bone health, mood and cognitive functions. It also says that sun exposure, through the regulation of melatonin also helps to properly establish circadian rhythms, improve sleep quality, and optimizes physical and social activity in the elderly.[1] They might have also mentioned that cognitive decline is much more prevalent among nursing-home residents that do not participate in outdoor activity; those who have 20 or more outdoor activities per month have no decline whatsoever![2]

This is especially important for institutionalized elderly people who tend to spend time in their rooms and asleep in front of the TV. The researchers suggest that the elderly should perform outdoor activities for 20-30 minutes per day, five days per week. They also suggest that the outdoor environment be more accessible to the residents and that some of their programmed activities should be held outdoors.

This is excellent advice and really hits home with me, since my wife and I have a church calling in which we conduct meetings and otherwise take care of the spiritual needs of the residents at an assisted-care facility. We see the physical and mental deterioration that takes place among the people who seldom get outside. We are always suggesting to our charges, and to the people who run the facility, that they get regular sun exposure and eat correctly, both of which would make dramatic differences in their abilities to cope.

Did you know that the risk of being admitted to a nursing home can be predicted by vitamin D levels?  In one investigation, those whose serum vitamin D levels were in the deficient category had three-and-one-half times the risk of being admitted to a nursing home as those whose levels were in the highest category.[3] Of course, people with low vitamin D levels are suffering from sun-exposure deficiency. Let’s take care of our elderly by being sure that they enjoy plenty of safe sun exposure.

[1] Lin TC, Liao YC. The Impact of Sunlight Exposure on the Health of Older Adults. Hu Li Za Zhi. 2016 Aug;63(4):116-22.

[2] Suzuki T, Murase S. Influence of outdoor activity and indoor activity on cognition decline: use of an infrared sensor to measure activity. Telemed J E Health. 2010 Jul-Aug;16(6):686-90

[3]  Visser, M. et al.  Low serum vitamin concentrations of 25 hydroxyvitamin D in older persons and the risk of nursing home admission.  Am J Clin Nutr 2006;84:616-22.

 

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Men, protect your Prostate!. Research demonstrates a positive influence of Sun Exposure on Prostate Cancer.

By Marc Sorenson, EdD. Sunlight Institute.

Regular sun exposure is one of the best ways to reduce the risk of many cancers. Although the relationship of sun exposure (and vitamin D) to the risk of prostate cancer is controversial, a study from Australia, published in 2011, showed that the less sun exposure, the greater the risk of the cancer.[1] The researchers investigated the relationship between prostate cancer incidence and solar radiation in non-urban Australia and found an inverse association. There are many other studies that indicate a protective effect of sun exposure. One of the earliest was conducted by Dr. Esther John and her colleagues: they compared the lifetime sun exposure of 450 white men with advanced prostate cancer to that of 455 white men who did not have cancer.[2] The men were divided into quintiles according to the amount of exposure they had received.  Subjects in the highest fifth of sun exposure had only 51% of the risk of prostate cancer as did those in the lowest quintile.

Another study on cancer that corroborated these observations was entitled: Is prevention of cancer by sun Exposure more than just the effect of vitamin D? A systematic review of epidemiological studies.[3] In their review, the authors noted that regular sun exposure correlated to a reduced risk of colorectal cancer, prostate cancer, breast cancer and non-Hodgkin’s lymphoma (NHL). However, vitamin D levels correlated to a reduced risk of colorectal, and to a lesser extent, breast cancer, but were not correlated to a significant risk reduction in prostate cancer and non-Hodgkin’s lymphoma. The authors concluded with this statement: “Particularly in prostate cancer and NHL, other sun-potentiated and vitamin D-independent pathways, such as modulation of the immune system and the circadian rhythm, and the degradation of folic acid, might play a role in reduced cancer risk as well.” These researchers did well to remind us, that as important as vitamin D is to the human body, other effects of sun exposure may be more important in some diseases. The authors could have also mentioned the effect of sun on vasodilation, mediated by the production of nitric oxide (produced by the skin after sun exposure). They could also have discussed the influence of sun on production of serotonin and endorphins, all of which may have contributed to their observations.

Other research used childhood sunburn as a measure of UVR exposure and determined that men who had sunburned as children had only about one-fifth the risk of contracting prostate cancer as those who had not sunburned.[4]  A note of caution! We are not recommending that anyone sunburn in order to prevent prostate or other types of cancer. Sunburn was used in this research to predict higher vitamin D levels, but it is not necessary to achieve those levels, since non-burning sun exposure achieves the same results. This research also demonstrated that men with lowest level of UVR exposure had more than triple the risk of prostate cancer and that onset of the disease was delayed more than four years in those who had the greatest exposure compared to those who had the least exposure.  A follow-up to this study, reported that men in the lowest quartile of sunbathing were linked to a 5.33-fold greater risk of prostate cancer than those in the highest quartile. Still other research has indicated that “higher levels of cumulative exposure, adult sunbathing, childhood sunburn and regular holidays in hot climates were each independently and significantly associated with a reduced risk of this [prostate] cancer.[5]

So men, protect your prostate by regular, non-burning sun exposure. Don’t let the Powers of Darkness frighten you away from the sun.

[1] Loke TW, Seyfi D, Khadra M. Prostate cancer incidence in Australia correlates inversely with solar radiation. BJU Int. 2012 Apr;109 Suppl 3:75.

[2] John EM, Schwartz GG, Koo J, Van Den Berg D, Ingles SA.  Sun exposure, vitamin D receptor gene polymorphisms, and risk of advanced prostate cancer.  Cancer Res 2005;65(12):5470-79.

[3] van der Rhee H, Coebergh JW, de Vries E. Is prevention of cancer by sun exposure more than just the effect of vitamin D? A systematic review of epidemiological studies. Eur J Cancer. 2013 Apr;49(6):1422-36.

[4] Moon SJ, Fryer AA, Strange RC.  Ultraviolet radiation: effects on risks of prostate cancer and other internal cancers.  Mutat Res 2005;571(1-2):207-19.

[5] Bodiwala D, Luscombe CJ, Liu S, Saxby M, French M, Jones PW, Fryer AA, Strange RC..  Prostate cancer risk and exposure to ultraviolet radiation: further support for the protective effect of sun.  Cancer Lett 2003;192:145-49.

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Summer Sunlight Exposure increases Growth in Children

By Marc Sorenson, EdD, Sunlight Institute..

Just when one thinks that there is nothing new that sunlight can do, new research belies that idea. It has now been shown that among children who growth-hormone deficient, and are being treated for that deficiency, growth is more rapid during summer months.[1] In a one-year study using 118 children from 14 countries as subjects, growth was measured and compared to the amount of sunlight received by the children. Those who were exposed to more sunlight had faster growth. The investigators also implicated a role for circadian-clock pathways in influencing growth (see my previous blogs on the importance of sunlight in correctly setting the circadian clock).

Although this research was claimed to be the first to demonstrate an influence of sunlight on accelerated growth among children being treated with growth hormone, another investigation from 2013 came to the same conclusion. [2] Others have also observed that children seem to grow more rapidly in summer. [3] [4] [5]

We want our children to have reasonable rates of growth, and the vitamin D produced by sunlight may produce larger and stronger bones. Or, it may be another factor such as nitric oxide, serotonin, endorphins or other less studied photoproducts. Whatever the mechanism, we now know that sunlight has one more critically important effect on human health, this time for our children.

[1] De Leonibus C, Chatelain P, Knight C, Clayton P, Stevens A. Effect of summer daylight exposure and genetic background on growth in growth hormone-deficient children. Pharmacogenomics J. 2015 Oct 27. [Epub ahead of print].

[2] Dorothy I Shulman, James Frane, and Barbara Lippe. Is there “seasonal” variation in height velocity in children treated with growth hormone? Data from the National Cooperative Growth Study. Int J Pediatr Endocrinol. 2013; 2013(1): 2.

[3] Marshall WA. Evaluation of growth rate in height over periods of less than one year. Arch Dis Child. 1971;46:414–420.

[4] Lee PA. Independence of seasonal variation of growth from temperature change. Growth. 1980;44:54–57.

[5] Joseph Gigante, M.D, Banderbilt Children’s hospital, Nashville, Tennessee. http://www.parenting.com/article/way-kids-grow.

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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.

[ii] http://dictionary.reference.com/browse/circadian%20rhythm?s=t

[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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Circadian Rhythms and the Critical importance of Sunlight. How to get back in Sync!

By Marc Sorenson, EdD, Sunlight Institute

When you stay up late at night and then sleep too late, you may not feel like all systems are functioning properly; they probably aren’t. You may be out of rhythm, and need a reset. The healing power of the morning sun will be your best medicine and will help you to resynchronize your rhythms.

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.[1] 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.[2] 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 post, 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.”[3] Anything that has a profound effect on all metabolic processes is obviously important to the proper functioning of the human organism. Therefore, when circadian rhythms are disrupted (or desynchronized), 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,[4] as measured by telomere length, a DNA marker for life span—the shorter the telomeres, the shorter the life span. The research demonstrated that young rats that were experimentally “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.[5] 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;[6] [7] even the risk of poor dental hygiene and dental caries are increased by desynchronized circadian rhythms.[8]

One might ask why a post on sunlight makes such an emphasis on circadian rhythms. Here is the answer: Sunlight can, and should, be the trigger that resets 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.[9] [10]

This is another positive benefit of sunlight that occurs apart from vitamin D production. There is almost no end to the health-promoting effects of the sun.

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

[2] http://dictionary.reference.com/browse/circadian%20rhythm?s=t

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

[4] 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]

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

[6] 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.

[7] 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]

[8] 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]

[9] 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.

[10] 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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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. http://sciencenordic.com/morning-light-relieves-anxiety Accessed August 8, 2015.

[iii] http://sciencenordic.com/morning-light-relieves-anxiety. Accessed August 8, 2015

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Early-Life Sun Exposure Affects the Age of Onset of Bipolar Disorder.

By Marc Sorenson, EdD

We are meant to be in the sunlight for both mental and physical health, and one of the most important phases for sunlight exposure is early life. We have previously discussed such diseases as autism, low bone strength and type-one diabetes as being related to lack of sunlight either in the formative years or even in the womb.

One of the latest pieces of research involves the onset of bipolar disorder (BD), a mental condition characterized by alternating mania and depression, usually interspersed with normal mood. The disorder was previously called manic-depressive illness.

In an 11-nation study, the U.S. was found to have the highest rate of BD and India lowest rate.[1] Or perhaps we should use the word “risk” rather than “rate.” Is it possible that greater sunlight exposure plays a part in India’s lower risk? Research has yet to determine that answer, but a recent study may “shed some light” on the subject. In the Journal of Psychiatric Research, a team of about 50 scientists studied the influence of light exposure during early life on the age of onset of BD.[2] The study covered 23 different countries at different latitudes and assessed light exposure in the early lives of 3896 BD patients. It was found that more sunlight exposure in the first three months of life was associated with a later onset of the disease. The researchers felt that sunlight during this time helped set the circadian rhythms later in life. The researchers concluded with this statement: “This study indirectly supports the concept that early life exposure to light may affect the long term adaptability to respond to a circadian challenge later in life.”

It would be interesting to know if the overall risk of BD is lower in countries or areas where people receive the most sunlight in infancy, of for that matter, during a lifetime. This research, however, shows us that our children, even our little ones, should receive regular, non-burning sunlight exposure.

[1] Amanda Gardner. U.S. has highest bipolar rate in 11-nation study. Heath.com. March 7, 2011. http://www.cnn.com/2011/HEALTH/03/07/US.highest.bipolar.rates/ Accessed July 21, 2015.

[2] Bauer M, Glenn T, Alda M, Andreassen OA, Angelopoulos E, Ardau R, Baethge C, Bauer R8, et al. Influence of light exposure during early life on the age of onset of bipolar disorder. J Psychiatr Res. 2015 May;64:1-8

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