Introduction

The earth has been bathing in sunlight for billions of years and life here has evolved with solar radiation. We are well adapted to the sun’s light. Sunlight is integral to life on this planet and we obtain many benefits from regular sun exposure. In fact, many illnesses and diseases are associated with a lack of sun exposure. Most of today’s conventional medical advice cautions us to protect ourselves from the sun and to even avoid sun exposure. This advice is contributing to more harm than good. For thousands of years, cultures throughout the world have practiced some form of heliotherapy, using sunlight to heal a variety of conditions. We have many built-in mechanisms that protect us from the supposed harmful effects of too much solar radiation. These adaptations combined with mindful sun exposure can improve overall health and well-being.

Invisible Light

The sun emits a huge amount of energy which includes cosmic rays, gamma rays, x-rays, ultraviolet (UV) light, visible light and infrared (IR) light (6). Most of the light that reaches earth is visible (about 45%) and infrared light (about 50%). Very little UV light reaches the earth. UV light is present during the middle part of the day, followed by visible light which is present most of the day then infrared light which is present all day. Infrared light is divided into near-infrared or infrared A (IRA), mid-infrared or infrared B (IRB), far-infrared or infrared C (IRC), but most of the infrared radiation that we are exposed to is IRA (700 to 1400 nm). Infrared radiation (and visible light) can penetrate deep into tissues and organs. Infrared is present all day and there are higher IR to UV ratios closer to sunrise and sunset, during the morning and later afternoon/evening. UV light transmission depends on many factors. Time of day, season of the year, geographical location (latitude and altitude), weather conditions and air pollution all affect the transmission of UV light (2). The UV spectrum ranges from far-UV or UVC (200 to 280 nm) which does not penetrate the atmosphere due to the ozone layer to mid-UV or UVB (280 to 320 nm) to near-UV or UVA (320 to 400 nm) which has the longest wavelengths compared to the other UV ranges. It is estimated that about 5% of UVA and less than 1% of UVB from the sun reaches earth (6) and of this approximately 90% to 95% of UVA and 5% to 10% of UVB in solar radiation reaches human skin (8) under ideal conditions (noon time in the tropics). It is UVB radiation that is responsible for the production of vitamin D in the body.

The Solar Hormone

Light is converted to a chemical signal in the body. When skin is exposed to sunlight, cholesterol absorbs UVB, it is photolyzed by UVB to pre-vitamin D3 which is then converted to vitamin D3 (cholecalciferol), then hydroxylated to form 25(OH)D in the liver, then transported to the kidneys where it is converted to 1,25(OH)2D (calcitriol) (3, 6). The skin has a large capacity to produce vitamin D and a single whole body exposure to an amount of sunlight equivalent to the minimal erythemal dose (MED) is approximately 10,000 units of vitamin D (10). The MED is the minimal amount of UV light needed to turn the skin slightly red which depends on skin type and is more noticeable in light skinned individuals. With our skin’s ability to generate vitamin D from sunlight, most of our vitamin D should be obtained from solar radiation and not supplements.

Vitamin D is a hormone that maintains bone health, supports immune and endocrine function, is essential to the nervous and cardiovascular systems and more – every organ and system needs vitamin D. None of our organs or systems can function optimally without vitamin D and essentially every tissue and cell in the body has vitamin D receptors (1, 5). Vitamin D interacts with its receptor to unlock genetic information that controls numerous metabolic processes including DNA repair, antioxidant activity, regulation of cellular proliferation and differentiation (6). Vitamin D controls many genes. As many as 2,000 genes may be directly or indirectly regulated by vitamin D (6). Many types of cells in the body can convert the inactive form of vitamin D into its active form calcitriol (1, 6). Vitamin D is also essential for proper mitochondrial function. These all indicate the importance of vitamin D for health.

The exposure of our skin to UVB radiation is the main way we produce vitamin D, not through food or supplements. UVB generates 90% of the body’s vitamin D. We should not ignore our body’s natural capacity to produce vitamin D through adequate sun exposure (1). Vitamin D supplements, including vitamin D3, are not effective substitutes for adequate sun exposure (5). It was found that chronic sub-erythemal UV doses caused only a modest increase in serum 25(OH)D levels but led to a greater disease suppression than vitamin D supplements without side effects (11). It is unlikely that any benefits of sun exposure could be obtained through dietary vitamin D supplementation alone (4). Orally administered cholecalciferol rapidly accumulates in adipose tissue and it is very slowly released preventing unregulated production of 25(OH)D and it only releases vitamin D during fasting conditions (10). This means oral vitamin D is not easily utilized by the body. Storage of vitamin D3 in adipose tissue can actually reduce serum bioavailability (10). These are several reasons not to supplement with oral vitamin D.

Vitamin D production from sunlight is well regulated, there are feedback mechanisms to prevent unregulated production in the body. Prolonged exposure of sunlight, unlike excessive consumption of vitamin D supplements, does not induce vitamin D toxicity because the skin has the ability to photo-degrade pre-vitamin D3 and vitamin D3 as it is formed (10). UVB-induced dermal activation of pre-vitamin D3 can produce multiple non-vitamin D metabolites such as lumisterol, tachysterol and others that limit the excessive formation of vitamin D3 (10). With the exception of food fortified with vitamin D, excessive consumption of dietary vitamin D from natural sources in food is very unlikely to induce vitamin D toxicity (10). It is still beneficial to eat salmon and mushrooms even if we do get most of our vitamin D from the sun. Sunlight and foods that naturally contain vitamin D have no side effects unlike supplements. Supplement-induced vitamin D toxicity can cause hyperphosphatemia, hypercalcemia, anorexia, fever, vomiting, headache, polydipsia, polyuria, renal stones, weakness and even cardiac arrhythmias (10). It is best to obtain vitamin D naturally through the sun as nature intended.

Preventing Disease With Solar Radiation

Exposure to UV radiation is an important environmental signal which plays an important role in the prevention, initiation and progression of many diseases (7). Vitamin D deficiency increases the risk for many diseases. Vitamin D deficiency is associated with many types of cancer, cardiovascular disease, diabetes, obesity, multiple sclerosis, allergy, asthma, infections, depression, dementia, neurodegeneration, autoimmune diseases and numerous other conditions (7). In regards to cancer, sun exposure reduces the risk for many types including but not limited to breast, colorectal, prostate, bladder, pancreatic and non-Hodgkins lymphoma (5). Sunlight can improve metabolic syndrome. Higher vitamin D levels and other UV-induced mediators were associated with lower prevalence of metabolic syndrome, improving diabetes and obesity and can prevent the development of non-alcoholic fatty liver disease (5). Solar radiation may prevent and slow the process of neurodegeneration. Low levels of vitamin D are associated with cognitive decline and Alzheimer’s disease (5). Regular sun exposure can improve eyesight and prevent eye diseases such as myopia. Children who spend more time outdoors are less likely to become myopic regardless of whether their parents are myopic or how much near work they do since UV and sunlight in general stimulates the release of dopamine from the retina which inhibits increased axial elongation that occurs in myopia (5). Most of the aforementioned diseases increase in incidence with increasing distance from the equator. Multiple sclerosis is most notably correlated with increased latitude. Adequate sun exposure should be prescribed for the millions who suffer from these preventable diseases. Vitamin D levels are a proxy for UV light exposure and low vitamin D levels are a result rather than a cause of disease (5).

Skin cancers are often associated with excessive exposure to solar UV radiation and is perhaps the main reason why people avoid the sun. However, sun exposure may actually improve survival rates in people with skin cancer. Chronic exposure to UV radiation reduces or delays the development of melanoma, the most lethal of skin cancers (7). Non-burning sun exposure is associated with a reduced risk of melanoma while sunburns are associated with doubling the risk of melanoma (5). Sporadic exposure to UVR is what causes burning as well as lack of the longer wavelengths (IRA) that are present in sunlight during the morning and late afternoon/early evening. Melanoma is more frequent among those who work indoors (7). Occupational outdoor sun exposure has been associated with a reduced risk for skin cancer (5, 6). Sadly, most people spend their occupational time indoors which prevents them from acclimating to solar radiation. Sun exposure is associated with increased survival from melanoma (7). Cancer patients who have a higher cumulative sun exposure have better chances for survival (4). Inadequate acclimatization to UV radiation in daily life carries the risk of sunburn and a corresponding increase risk of both non-melanoma and melanoma skin cancers (5). Regular sun exposure is protective against skin cancer. Could it be that the sun may not be the direct cause of skin cancers?

Nitric Oxide

When skin is exposed to UVA radiation, cutaneous stores of nitric oxide are released. Nitric oxide is a gaseous free radical. Not all free radicals are damaging, some are used for signaling. Nitric oxide causes vasodilation, provide immune defense, aids in neurotransmission, regulates apoptosis and cell motility (7). Nitric oxide has anti-microbial effects. It is effective in tissue disinfection and regulating inflammatory processes associated with acute and chronic wounds, is involved in cutaneous wound healing and it even has anti-tumor activity (7). Nitric oxide may then protect against cancer formation. Nitric oxide may also protect against other free radicals that induce oxidative stress. It was also found that low concentrations of nitric oxide protect cultured keratinocytes and skin from oxidative stress (7).

Nitric oxide stimulates vasodilation which can lower blood pressure (1, 4, 5). Nitric oxide is converted to nitrite which is delivered into systemic circulation and exerts coronary vasodilation and has cardio-protective and anti-hypertensive effects (7). This is the mechanism by which sunlight can reduce blood pressure and improve hypertension. In one study where participants were exposed to UVA, diastolic blood pressure fell by about 5 mm Hg and remained low for 30 minutes after exposure (1, 4). Hypertensive patients may need less medication and can even be weaned off medication with adequate sunlight exposure. Blood pressure is lower in the summer compared to other seasons and both systolic and diastolic pressure increases as distance from the equator increases (6); this may be related to both nitric oxide and vitamin D production.

Sunlight can improve obesity and diabetes. UV-induced nitric oxide significantly suppressed weight gain, glucose intolerance, insulin resistance, serum levels of fasting insulin and glucose and these effects were independent of vitamin D production and could be reproduced with nitric oxide (4, 11). Diabetes patients who receive adequate sun exposure may be able to reduce their medication since UV light is quite effective in normalizing blood sugar. When skin and eyes are exposed to UV light, it activates pro-opiomelanocortin (POMC) from POMC-responsive neurons in the hypothalamus which may reduce appetite and food intake (4). POMC is an opioid polypeptide secreted by the skin cells, neurons and the pituitary gland that triggers the release of important peptides such as alpha-melanocyte stimulating hormone (MSH) and beta endorphin (4). MSH may help prevent obesity by suppressing appetite and enhancing catabolic signals to promote energy consumption (4). Vitamin D supplements are not as effective as sunlight in controlling diabetes. UV light exposure levels reduces the risk for obesity and Type 2 diabetes, not vitamin D supplements or 25(OH)D levels (5). Regular sun exposure has a tremendous potential to improve metabolic syndrome.

Endorphins

The feelings of well-being when out in the sun are the result of endorphins released by the body in response to solar radiation. Both UVA and UVB increases the expression and production of beta endorphins (6) and IRA can also produce endorphins as well (2). UV radiation increases the expression of POMC which results in production of beta endorphins (6, 7, 8). Beta endorphin is an endogenous opioid peptide that increases feelings of well-being, promotes relaxation, relieves pain, promotes wound healing and supports the immune system (1, 6). Beta endorphin released into the blood during UV exposure may reach the brain to induce mood enhancement and relaxation (7). Beta endorphin is responsible for ‘runner’s high.’ Tanners feel more relaxed and less tense than non-tanners since sunlight has been linked with elevated mood (7). It’s not surprising why sunbathers seem to be addicted to the sun. Sun exposure is designed to be addictive, the release of beta endorphins is a natural reward mechanism that encourages more sun exposure (5). Because beta endorphin is an analgesic, it can help those suffering from chronic pain such as individuals with osteoarthritis, rheumatoid arthritis and fibromyalgia. It was found that sunbathing reduces pain in patients with fibromyalgia (7). Sunlight deprivation is associated with depression (6). Seasonal affective disorder is most likely caused by a lack of exposure to sunlight during the winter. A trip (or several trips) to a sunny locale can relieve the gloom that most people feel in the wintertime.

Immune Protection

As mentioned earlier, vitamin D from UVB exposure supports the immune system and nitric oxide from UVA radiation has anti-inflammatory and anti-microbial effects. UVB induces local and systemic immunosuppressive effects (7). UVB-induced immunosuppression may have arisen to prevent auto-immune responses to inflammatory products resulting from UV-mediated damage (3). This explains how UV radiation alleviates auto-immune conditions. UVA can provide immuno-protection and inhibit UVB-induced immunosuppression through modulation of various cytokines and enzymes (7). UVA exposure mediates anti-oxidant, anti-inflammatory, anti-apoptic and anti-proliferative effects protecting cells against oxidative stress (7). Regardless of whether the body needs immune support or immune suppression, it has an innate intelligence which allows it to utilize both forms of UV radiation to its benefit. IRA also supports the immune system by reducing inflammation, improving circulation, promoting regeneration, among other things.

Treating Skin Conditions

Solar radiation can improve skin conditions. Skin exposed to UV light is more resistant to primary irritants which indicates the improvement of skin barrier functions (7). Phototherapy is used to treat several skin conditions. UVA and UVB treatments are used to treat atopic dermatitis and other inflammatory skin diseases (7). UVB light has been effective in managing psoriasis by inhibiting cutaneous immune function (7). Psoriasis often improves during the summer. UV also helps with vitiligo. Vitiligo sun-exposed lesions showed re-pigmentation during the summer months (7). IRA encourages regeneration and can rejuvenate the skin. IRA has numerous benefits such as improving collagen metabolism, increasing expression of anti-inflammatory cytokines, suppressing inflammation and promoting healing (2). Polymorphous light eruption or photosensitivity in individuals can be treated with IRA (2) from morning and late afternoon/evening light. Most burning and photosensitivity occurs from acute exposure to UV radiation combined with inadequate exposure to IRA. It is less likely to occur if sun exposure is gradual and chronic. Many skin conditions can be treated with proper full spectrum sunlight exposure at specific times during the day.

Circadian Rhythms

Perhaps one of the most critical reasons for exposing your body to the sun is the regulation of circadian rhythms. Sunlight is the most important zeitgeber and is responsible for normalizing circadian rhythms. Light signals received throughout the eyes signal to the master timekeeper in the brain, the suprachiasmic nucleus, that it is daytime and this keeps time in all the peripheral clocks in the body so that they can function properly. All cells express genes that are able to keep cellular time, these clock genes regulate gene expression and activity (6) which emphasizes the importance of cells receiving the proper light cues to tell time in order to function optimally. When cultured human keratinocytes were exposed to UVB, there was a significant increase in the expression of two clock genes that play an important role in cellular circadian activity (6). Decreased sunlight exposure during the daytime can negatively affect circadian rhythms and nocturnal melatonin peak production (11). Melatonin, the hormone responsible for sleep, is optimally produced from adequate sunlight signals during the day. Melatonin also has anti-cancer effects and normal melatonin production and therefore normalized circadian rhythms are essential for cancer prevention. Circadian disruption has been linked with carcinogenesis, metabolic syndrome (11) and can cause other diseases as well.

Innate Protective Mechanisms

Human skin is repeatedly exposed to many potentially damaging environmental agents. We have many mechanisms to protect us from the free radical damage that UV radiation causes (3, 5). We were designed to absorb and utilize UV radiation since we have numerous chromophores in many layers of the skin such as nucleic acids, aromatic amino acids, and melanin precursors (7, 8). These chromophores are designed to be excited by and to utilize light and their molecular structure changes in response to light, they don’t just disintegrate. Skin adapts to chronic UV radiation by increasing melanogenesis, thickening of the skin, activation of DNA repair systems, triggering cell cycle and growth inhibitors, enhancing cellular differentiation and sensitivity to apoptosis, increasing antioxidants and initiating anti-inflammatory effects (3, 5, 7). Skin that is not chronically exposed to UV radiation is more easily burned, indicating that we should be receiving regular, chronic sun exposure.

Melanin is responsible for skin absorbing UV radiation, causing pigmentation and is the body’s first line of defense against radiation. Melanin absorbs approximately 50% to 70% of UV radiation and has a sun protective factor (SPF) of 4 (3). The more pigmented the skin is, the more protected it is from UV radiation. Melanin is able to dissipate UV radiation as harmless heat (9). When exposed to UV radiation, skin pigmentation increases which protects us from future UV radiation exposures. Melanin is an extremely efficient sunscreen which acts as an anti-oxidant and free-radical scavenger, reducing damage from UV light (3, 6, 7). The photo-protective function of skin resides primarily in the keratinocytes in the outer layers of the epidermis while the melanin pigment-producing melanocytes are embedded in the basal layer of keratinocytes of the epidermis (8).

DNA is often assumed to be easily damaged by UV radiation but it has protective mechanisms similar to melanin. In all skin types, DNA damage occurs mostly in the upper layers the epidermis while the lower layers of the skin are protected as melanin content increases (3). This means that during sun exposure, skin is being repaired almost as quickly as it is being damaged by producing more melanin. Melanin is packaged into melanosomes that are released into the epidermis where they settle over the perinuclear area of epidermal cells and act as an umbrella or cap, thereby shielding DNA from radiation (3, 6, 8). DNA absorbs light very strongly and protects itself by dissipating the UV radiation as heat instead of breaking the chemical bonds which hold it together, this occurs in as little as 200 femtoseconds (12). This is almost instantaneous dissipation of heat. Regular exposure to UV light leads to an almost complete disappearance of DNA damage in the basal and supra-basal layers in the epidermis where the initiation of skin cancer occurs (11). Vitamin D produced from UVB can also initiate DNA repair mechanisms (5).

Tanning is protective and both UVA and UVB can increase skin pigmentation. There are several types of tanning responses in the skin. UVA radiation causes the oxidation of pre-existing melanin as well as re-distribution of this exiting melanin to cause immediate pigment darkening (in as little as a few minutes and lasts for hours) and persistent pigment darkening (in a few hours and lasts for several days to weeks) (7, 8), respectively. Since UVA penetrates deeper into the dermis than UVB which only reaches the epidermis (9), UVA is responsible for long-lasting pigmentation (7, 8). Meanwhile, UVB causes melanin synthesis that results in delayed tanning which develops a few days later and lasts for several weeks, just as long as (or sometimes even longer than) tanning induced by UVA (3, 7, 8). UVB-induced pigmentation results in a protection which is as large as corresponding to a factor of about 2 to 3 against DNA photo-damage and erythema (7) and is equivalent to an SPF of 3 (3). Exposure to solar radiation produces our own internal sunscreen. UVB causes much more erythema than UVA being 1000 times more erythematogenic than UVA because of it’s higher energy (shorter wavelength) (3, 9). It is UVB radiation that causes burning in individuals not acclimated to regular sun exposure. Visible light (400 to 700 nm) can also induce tanning but UV radiation is 25 times more efficient at increasing pigmentation (8).

Darker skin is better equipped to deal with radiation than light skin. UV radiation-induced damage is decreased in darker skin and darker skin is more efficient at removing damaged skin than lighter skin (3). There are two types of melanin, eumelanin and pheomelanin. More eumelanin is found in darker skin types while more pheomelanin is found in lighter skin types. Eumelanin is more effective at photo-protection than pheomelanin and eumelanin serves as a barrier that scatters UV light and reduces the penetration of UV radiation through the epidermis (3). Eumelanin is also less prone to degradation than pheomelanin. Very light skin allows about 24% of UVB and 55% of UVA to be absorbed while very dark skin allows about 7% of UVB and 17% of UVA to be absorbed (3). This means that the darker you are, the more time you need to spend in the sun to get the benefits of solar radiation. Darker pigmentation confers protection which enables you to stay out in the sun longer. Conversely, the lighter you are the less time you need to spend in the sun but with increasing pigmentation means you have to increase your time spent outside to reap the benefits of sunlight. Protection agains sunburn arises from photoadaptation (5). In geographical areas of high UV exposure such as the tropics, there is a natural selection for dark skin to protect against sunburn (3). Being tan and having darker skin protects against skin cancer. There is a lower incidence of skin cancer in darker skinned individuals than those who are lighter skinned (3). There is an inverse relationship between skin pigmentation and incidence of skin cancers (3).

UV radiation initiates a series of pathways that result in photo-protection. UV radiation increases the expression of POMC which triggers production of MSH which then leads to melanin production (7, 8), further protecting the skin from radiation. Increased MSH secretion causes melanocyte proliferation and increased melanogenesis (8). Melanocortins produced from POMC such as MSH, adrenocorticotropic hormone (ACTH), and melanocortin 1 receptor (MC1R) rescue melanocytes from apoptosis induced by UV light, they activate DNA repair and antioxidant pathways (3). As mentioned earlier, nitric oxide produced from UVA light has anti-inflammatory effects and can protect against oxidative stress. UVA-induced nitric oxide production protects the skin against solar radiation-induced damage within 20 to 30 minutes, depending on the UVA dose (7). UVB-induced vitamin D production can stimulate repair and anti-inflammatory effects, also protecting the skin.

The skin thickens with chronic exposure to sunlight as another adaptation to radiation. In response to sun exposure, skin increases the amount of the upper dead layer of the stratum corneum, the outermost layer of the epidermis, which acts like a mirror to reflect and refract UV radiation (6). However, tanning provides a higher protection against UV radiation than does epidermal thickening (3). When skin damage is too great to be repaired, apoptosis occurs. Programmed cell death of UV damaged skin cells is a definitive cancer-preventing pathway (9). In a sunburn, large numbers of keratinocytes will undergo apoptosis to prevent malignant transformation (9). A sunburn is the body trying to protect itself from cancer. We have many innate mechanisms and adaptations to protect ourselves from any damaging effects of solar radiation.

Protective Measures For Safe Sun Exposure

Exposure to the full solar spectrum is essential to optimal health and well being (1) which is why it is important to be outside not just during solar noon when UVB is present but to be outside most of the day. Typically humans would have been exposed to sunlight all day from dawn to dusk. Infrared light is present all day but it is during the times closer to sunrise and sunset, during the morning and the late afternoon/evening that IR light is most prevalent due to the lack of UV light. In other words, closer to sunrise and sunset, the amount of IR is greater than the amount of UV radiation. IRA is responsible for photo-protection from the shorter wavelengths of UV radiation (2).

Photo-protection employs mostly IRA and visible light. Visible light and infrared light are able to penetrate much more deeply into the skin to reach the internal organs (6). Photobiomodulation uses light, particularly red and infrared light, to regulate biological processes. Since most of the light that comes from the sun is infrared and infrared is present all day, exposure to sunlight is natural photobiomodulation. Photobiomodulation that emulates the conditions of natural sunlight in wavelength, intensity and dosage are beneficial for the skin (2). In one study, subjects were pre-treated with red light prior to UVB exposure while controls were not pre-treated with any light, the results showed a reduction in erythema in a significant number of subjects, providing an SPF of 15 and a reduction in post-inflammatory hyper-pigmentation (2). Red and infrared light are most prevalent at sunrise and sunset. Exposure to light at these times aids in photo-protection.

IRA light in the morning and late afternoon/evening can prepare and repair skin, respectively, from UV radiation. Morning light prepares the skin for the coming UV rays while late afternoon/evening light repairs any damage that occurs after UV exposure (2). Exposure to IRA light during these times closely emulates the process found in nature by pre-conditioning the skin before the actual injury by stronger radiation levels occurs (2). In many equatorial pre-industrial societies, people would work outdoors in the morning which allowed them to endure the later mid-day sun. This is why it’s important to obtain natural light in the morning and evening. If your shadow is taller than you, it means that beneficial IRA is more available than UV radiation (2). Therefore, it is very important to expose your skin to sun, especially if your skin is prone to burning, to as much morning sunlight as possible, then adjust your exposure to mid-day sun until you have acclimated and finally to as much late afternoon/evening sun as possible to obtain the full benefits of sunlight. IRA has many benefits such as skin regeneration and preventing photo-aging.

Societal, Environmental And Chemical Barriers

Chronic non-burning sun exposure and outdoor occupations have been associated with reduced risk of melanoma (5). The problem is many people nowadays spend their occupational and leisure time indoors. Indoor workers are 8 times at higher risk of dying from cancer as compared with outdoor workers (6). Working and living indoors has many deleterious health consequences and is leading to epi-genetic changes in humans. Melanoma, the most deadly form of skin cancer, is often found on the least sun-exposed parts of the body (6, 10). This indicates that we are designed to obtain sun exposure over our entire body. Patients with early-stage melanoma who continued to receive high sunlight exposure showed increased survival (10). This indicates that sun may not be the cause of melanoma. Though not socially appropriate, it would be best to expose all your skin to the sun, in other words, it would be best to tan in the nude outdoors. Most clothing blocks higher energy light like UV light. Also, conventional advice recommends wearing UV-protective eye wear when out in the sun. This is leading to more harm than good. In order to obtain all the benefits of the full solar spectrum, avoid wearing sunglasses, prescription eyeglasses and contacts when outdoors because they alter the light that enters the eyes. The eyes need exposure to ambient natural light to signal to the master clock in the brain to normalize circadian rhythms among other things. This is especially important for those with myopia since this practice can prevent the worsening of myopia. Only sunlight exposure can prevent, halt and even reverse myopia.

Living at higher latitudes and acquiring less sun exposure increases one’s risk for developing many chronic illnesses and infectious diseases as well as increasing the chance of dying earlier (1, 6, 7). Cancer-related deaths decline in the lower latitudes where sunshine is more abundant (10). It’s ideal to live as close to the equator as possible, especially if you are darker skinned. Living at higher elevation from sea level (increased altitude) also increases your exposure to solar radiation. Clouds can block but can also scatter light. So regardless of whether it is sunny or cloudy, it should be a priority to spend time outdoors because natural light is beneficial. Nowadays, it is more difficult to get full spectrum sun exposure regardless of where you live. The heavy metals and other chemicals being sprayed into our atmosphere from geoengineering have altered the amount of sunlight that reaches the earth. Air pollution can limit UV light transmission, reducing UV transmission by 60% (5). Living in cities with excessive air pollution also reduces your sunlight exposure.

Sunscreens greatly reduce our ability to synthesize vitamin D and prevent our bodies from acclimating to UV radiation (5, 10). The more you use sunscreen, the more vitamin D deficient you will become. A sunscreen with an SPF of 30 absorbs approximately 95% to 98% of UVB radiation (10). With regular sunscreen use, you will be less likely to tolerate sun without sunscreen which means you can burn more easily. Sunscreen has never been proven to prevent skin cancer. There is no consistent evidence that the use of chemical sunscreens reduces the risk of melanoma (5). It’s best not to use chemical sunscreens at all and acclimate to the sun slowly beginning with regular exposure to morning and late afternoon/evening IRA light before spending significant amounts of time in mid-day sun. More time should be spent outdoors around sunrise and sunset depending on your skin type though it is beneficial for all skin types to be out at these times. Once you have reached the minimal erythemal dose, seek shade to avoid burning.

Life Indoors And Exposure to Artificial EMFs

Modern industrialized life has brought us indoors. Our sun exposure therefore became sporadic instead of chronic which was not what nature intended. The main reason for our lack of sun exposure is the change in our lifestyles and societal norms which has caused most of us to spend the majority of our time indoors. Our exposure pattern to sunlight has changed drastically from continuous to sporadic in this modern age (11) and this is leading to a decline in overall health. With more and more people spending the majority of their occupational and leisure time indoors, it’s no wonder that this has led to an increased prevalence of sunburns (5). Fear of being burned means that people will either avoid sun exposure or use sunscreen which prevents the formation of vitamin D. It is estimated that at least one-third of Americans suffer from vitamin D deficiency (5). The public health message of the past 50 years has been to avoid sun exposure and to use chemical sunscreens which has led to the finding that avoidance of sun exposure is a risk factor for death (5). Insufficient sun exposure has become a major public health problem, demanding an immediate change in the current sun-avoiding health advice (5). Another problem that industrialized societies have is the exposure of people’s eyes to artificial light in the daytime and in the evening which is a relatively new phenomena (11) that has numerous negative consequences most notably, interfering with our circadian rhythms. Lack of sunlight during the day and excessive exposure to artificial light day and night is paving the way for many diseases.

Artificial electromagnetic fields (EMFs) that generate radio frequencies (RF) and microwave (MW) radiation has biological effects. Since all biological processes from the microscopic to the macroscopic involve the movement of charged particles, organisms are extremely sensitive to artificial EMFs. Skin is affected by radio frequency radiation (8) even though it is considered non-ionizing radiation. RF radiation can penetrate deep into the skin and generate heat (8). Intense MW radiation can cause changes in the dielectric field within cells that increases friction between water molecules and can increase temperatures leading to damage (8). RF radiation also has numerous non-thermal effects on biological systems. All external EMFs are transduced to vibration or movement in molecules and cellular structures which is how non-thermal, non-ionizing radiation can have biological effects though biological systems are non-linear therefore effects are unpredictable.

We need to avoid and protect ourselves from artificial light and man-made EMFs. It’s not just our eyes that can detect light. Rhodopsin which is a photopigment present in the eye and involved in phototransduction has been found in melanocytes and contributes to phototransduction in these cells (8). Phototransduction is the conversion of light into an electrochemical signal. The skin can detect light similar to the way in which the eye detects light which has numerous implications. Exposure to artificial light that no where near resembles the solar spectrum of light such as white light LEDs are very problematic. Since we are exposed to artificial light during the day and night, this could be contributing to diseases ranging from circadian rhythm disruption to skin cancer. Could it be that most skin cancers are caused by artificial radiation rather than solar radiation? If less people today are getting chronic sun exposure and more people are exposed to dangerous electromagnetic fields from modern day technologies, the sun could be falsely blamed for skin cancer. Light pollution day and night poses a significant health hazard (8). Measured long-term or total sun exposure had found no association between cumulative sun exposure and either squamous cell carcinoma or basal cell carcinoma (5) which suggest that factors other than the sun may be involved in these types of skin cancers. It was found that prolonged use of mobile phones increases the risk for melanoma (8). Could it be that our intermittent sun exposure (or lack of continuous sun exposure) combined with our regular exposure to EMFs from modern technologies are causing skin cancers? With the electromagnetic spectrum continuously growing, it’s becoming more difficult to avoid man-made EMFs in most environments.

Conclusion

Sunlight regulates many biological functions and it’s of the utmost important to get safe and adequate sun exposure on a regular basis. Chronic sun exposure reduces the risk of many diseases and can even reverse disease. Sunlight should be used for disease prevention. Many of the sun’s benefits derive from vitamin D production but there are also many sun-induced non-vitamin D pathways that we benefit from such as the production of nitric oxide, endorphins and melatonin. We don’t need to supplement with oral vitamin D as long as we acquire adequate sun exposure because our bodies have a great capacity to generate this hormone. We have many innate mechanisms that protect us from solar radiation and therefore chemical sunscreens are not needed. If sun exposure is practiced wisely ensuring exposure to beneficial infrared light during the morning and late afternoon/evening hours, this enables photoprotection from overexposure to mid-day sun. Infrared light provides us with many other benefits as well such as healing and regeneration. Our indoor lifestyles and social norms prevent us from obtaining enough sunlight that we need, they are placing us at increased risk for developing disease and worsening disease progression by exposing us to man-made sources of radiation day and night from modern technologies. Artificial EMFs should be avoided as much as possible. We are born with an innate intelligence and have an enormous capacity to heal when we are out in the sun and enveloped in the natural world. The body chooses the wavelengths it needs from the full solar spectrum to function at its best. In order to pave the way for optimal health, we must embrace the sun and live as close to nature as possible.

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