Sunlight Exposure Lowers All-Cause Mortality

The Optics of Planet Earth

What is the light environment you live within daily? Did you know the light you experience shapes your health and longevity? It is the key determinant of whether you develop a chronic disease or maintain good health over the long-term. But light is not just the Sun vs LEDs. It's far more nuanced even the experts don't understand it well enough.

In the physics, astronomy, biophysics, quantum biology, photonics, optics, and circadian biology circles, there is still a surprisingly big misunderstanding of how Earth’s light environment is perceived and how it needs to be understood. We have apps that track the sun’s movement across the day, and we have lighting systems designed to mimic the visible spectrum, but most of these tools are not really considering the full optics of the planet, and because of that they often become inaccurate in their recommendations, their solutions, and their confidence. They oversimplify the environment humans evolved under, and they collapse a living planetary light field into a cartoon of “sun up equals blue, sun down equals red,” as if biology only cares about a direct beam. I was prompted to write this because I keep seeing that oversimplification everywhere, and I want to further the conversation by bringing together the discoveries and thinking from people like Robert Fosbury and Scott Zimmerman, alongside the broader community of astronomers, atmospheric optics specialists, and photonics minded researchers, plus my own measurements of hundreds of real spectral environments outdoors in both modern and natural landscapes. My aim here is simple. I want to expand your mind, and give you a deeper appreciation for how human life, animal life, insect life, plant life, and the entire web of biology has developed over time to create a negentropic, ordered living system we call the human body, all while embedded inside a dynamic optical field.

Sunlight is easy to talk about, but most people still misunderstand what they are actually receiving. They think sunlight is only the direct beam from the sun, as if the story begins when the solar disc clears the horizon and ends when it drops below it. The truth is that the light environment is a planetary optical system. It is direct solar radiation, yes, but it is also sky scattered light, reflected light, refracted light, absorbed light, and re emitted light. It is the way photons interact with atmospheric gases, water vapour, aerosols, clouds, soil, sand, stone, plants, ocean surfaces, and even our built materials like glass, asphalt, concrete, and steel. Biology is not merely under the sun. Biology is inside an optical field. We say the sky is blue, but that is partly a human perception story because our cones weight what we notice. The scattering physics contains more high energy content than most people appreciate, and many insects and animals perceive the sky in a very different way, with far greater sensitivity to violet and ultraviolet. If you want to understand why biology responds so strongly to outdoor light even when it looks soft to your eyes, this is part of the answer.

Let’s start with the easy bit, the spectrum, because once you see it, you cannot unsee it. Sunlight is not just “light.” It is ultraviolet, visible, and infrared, all arriving together in ratios that constantly shift, but in a natural landscape are always accompanied by a dominant portion of 45% or greater infrared light. UV includes UVA and UVB. Visible is the seven colours we call the rainbow. Infrared is the long wavelengths beyond red, the part you feel and don’t’ see, and it is the dominant portion of solar energy. Most people obsess over the tiny sliver of UV like it is the whole movie, while infrared is sitting there doing the heavy lifting. Infrared is like the main actor, and UV is like the celebrity cameo in a few scenes throughout.

Now here is the key optical constraint. The atmosphere is not a neutral window. It is a selective filter, and its filter settings change. Water vapour absorbs strongly in parts of the infrared. So in humid air, some longer wavelengths do not reach the ground as efficiently. In drier air, more of those longer wavelengths can penetrate. This is why sometimes the longer wavelengths make it further down toward that rough 2,500 nanometer region, because there is less water absorption, while in wetter air you can feel that the deeper warmth is being “eaten” by the moisture. At altitude, you can also see a shift in the other direction. The air column is thinner, and often the moisture content is lower, so more energy makes it through and the sun can feel sharper and more intense. Sometimes, at altitude, even the shorter ultraviolet wavelengths are less attenuated, and you can feel the biological consequence of that immediately. It is not that those wavelengths do not exist at sea level. It is that the optical path and the atmospheric filter decide how much is delivered and in what ratio.

Most people stop the infrared conversation at about 2500 nanometers because that is roughly where a large portion of the direct solar infrared beam becomes heavily limited by atmospheric water absorption. But that is only the direct beam story, and it is the smaller story. The lived light environment includes far longer wavelengths because Earth is an infrared planet, meaning that once photons touch matter, the physics changes from transmission to transformation. A photon does not just arrive and disappear, it is absorbed, its energy is redistributed into molecular vibration and rotation, the local temperature rises, and that energy is then re emitted as longer wavelength radiation in the infrared, shaped by the material’s composition, water content, and structure.

So once sunlight reaches organisms and surfaces, reflectance, refraction, and thermal re emission become the real landscape optics. Soil, sand, leaves, bark, ocean surfaces, buildings, animals, and our own bodies continuously absorb shorter wavelengths and re emit longer wavelengths as heat. That emission is not a rounding error, it is the dominant background field you are living inside. Which means even if the atmosphere filters parts of the longer infrared from the direct solar beam, biology still experiences longer infrared through planetary optics, because everything that absorbs light becomes an emitter after it absorbs energy, and the planet is constantly recycling photons into longer wavelength infrared all around you.

The IR Bands of light that allow life to thrive

Astronomers have effectively handed us a map of the infrared atmosphere that biology has been living inside the whole time, and it comes in nine main transmission windows, I, Y, J, H, K, L, M, N, and Q. In practical wavelength and energy terms, the windows sit roughly here: I is 700 to 900 nm, about 1.77 to 1.38 eV, Y is 970 to 1070 nm, about 1.28 to 1.16 eV, J is 1100 to 1400 nm, about 1.13 to 0.89 eV, H is 1500 to 1800 nm, about 0.83 to 0.69 eV, K is 2000 to 2400 nm, about 0.62 to 0.52 eV, L is 3000 to 4000 nm, about 0.41 to 0.31 eV, M is 4500 to 5000 nm, about 0.28 to 0.25 eV, N is 8000 to 13000 nm, about 0.155 to 0.095 eV, and Q is 17000 to 25000 nm, about 0.073 to 0.050 eV. My opinion is that these windows matter because they represent the planet’s most reliable low scatter infrared delivery zones, meaning they act like a foundational oscillatory bath that life has always been immersed in, and then biology layers higher energy chemistry on top of that base.

Now to be precise, electron transfer inside mitochondria is driven by redox potential differences between carriers, typically on the order of a few tenths of a volt per step, rather than by photon energy directly, but I see a meaningful relationship here: near infrared photons in the 0.5 to 1.0 eV range overlap with energies that can influence vibrational states, water structuring, and chromophores like heme and copper centers, which is why timing and spectrum can alter how efficiently the system handles electrons and protons. Then when you move into ultraviolet, the energy jumps dramatically, UVA at 315 to 400 nm is about 3.9 to 3.1 eV and UVB at 280 to 315 nm is about 4.4 to 3.9 eV, which is why UV acts less like gentle background priming and more like a high leverage trigger for photochemistry, nitric oxide release, vitamin D synthesis, and the hormone and pigment cascades that sit on top of mitochondrial energetics.

Then we add geometry, because the planet is not flat and the sun does not shine straight down most of the day. The sun’s angle of incidence controls what wavelengths are delivered directly versus what is filtered, scattered, or lost. At sunrise and sunset, the light travels through a much longer atmospheric path. The shorter wavelengths get scattered and absorbed more, and what survives the journey is richer in red and infrared. Power density is lower, the spectrum is softer, and biology reads it differently. As the sun climbs, the path shortens, power density rises, and more short wavelengths arrive directly. This is one reason sunrise and sunset are so regulating. They are not just pretty. They are a spectral and energetic signal your biology evolved to interpret.

This is where the inclination numbers matter, and I want to give you a simple model you can hold in your head. When the sun is inclining and crosses roughly 10 to 15 degrees above the horizon, UVA starts to become much more present as a direct signal from the sun, not just as an atmospheric scattering phenomenon. When the sun continues to incline and crosses roughly 30 degrees, that is when UVB starts arriving as a meaningful direct beam and power density really kicks up. Then the sequence reverses on the decline. UVB drops out first once the sun falls below about 30 degrees, and UVA drops out next as it falls below about 10 to 15 degrees. Directly from the sun, those are the simple thresholds. Optically, the planet still contains UV in the field through scattering, reflection, and atmospheric optics, but the direct beam availability and biological intensity change dramatically around those inclination bands. And this matters, because people confuse “no direct UVB” with “no UV in the environment,” and those are not the same statement.

Latitude and season then rewrite the script again. In the tropics, the sun rises more steeply and reaches higher inclinations more consistently, so the UV windows arrive sooner and last longer. That means direct UVA and UVB exposure can show up earlier after sunrise and remain available for longer portions of the day. As you move farther from the equator, the sun spends more time low in the sky, especially outside summer. That means longer periods where UVB power density is not available directly, even though visible and infrared still dominate the day. In summer, because of Earth’s tilt, higher latitudes get longer days and higher solar elevations, so UVB windows open wider. The calendar anchors this. Around June 21 in the northern hemisphere you get the longest day and the highest solar elevations for that year. Around December 21 you get the shortest day and the lowest. The equinoxes around March 20 and September 22 are the balance points where day and night are roughly equal and the geometry is shifting between those extremes. Humans did not evolve under a static spectrum. We evolved under a dynamic geometry.

And because the world is a sphere, the southern hemisphere is the opposite seasonal mirror. June is winter, December is summer. So if anyone is like me and wants to chase summer and the sun, especially while recovering, rebuilding, or simply trying to live more optimally, you can go summer to summer. Northern hemisphere summer into southern hemisphere summer can give you a more consistent window of high solar elevation and strong UV presence across the year instead of spending half the year trying to run summer biology on winter photons.

The Optics of the Natural Environment

Now we get to the part most people truly miss. Sunlight is not only what comes straight from the solar disc. The sky itself is a light source. Rayleigh scattering distributes shorter wavelengths across the sky, which is why it appears blue to us, but perception plays a trick here because our cone sensitivities weight what we notice. The sky contains more complexity than the simple blue story. There is ultraviolet in the skylight field, including low density UVA and UVB components. There can be UV present before the sun is directly visible, at low photon densities, because the planet is already scattering and distributing photons through the atmosphere. That is why you can still receive biologically meaningful light exposure outdoors even when the sun is behind you or behind clouds. Direct sun increases power density, yes, but being outside is still being inside the optical field.

Natural materials are not just prettier. Many are porous and spectrally complex, which changes how they absorb, scatter, and re emit energy. In a natural setting, that porosity and complexity can support a richer optical environment. In an artificial setting, porous materials can be a double edged sword because they can allow more artificial light spill and spectral noise to leak through spaces. This is why material choice matters in architecture along with light choices, not just for aesthetics, but for optics.

This is also why people misunderstand exposure when they talk about “the sun has to be on you.” It helps, because the beam increases power density, but it is not the whole story. You can tan on your back without facing the sun directly if your skin is exposed to the air, because sky scatter and environmental reflections are still delivering photons. And when you add reflective environments, beaches, water, sand, snow, pale stone, you amplify high energy visible and ultraviolet exposure through reflection. That is why you can feel cooked sitting under a beach umbrella. The ocean and sand are not passive. They are optical multipliers.

Now let’s talk about living landscapes, because this is where the planet gets clever. When humans and animals walk through a natural environment, they are not only receiving direct sunlight. They are receiving the reflectance signature of the entire ecosystem. Chlorophyll absorbs strongly in visible wavelengths of blue and red used for photosynthesis and reflects a substantial amount of near infrared and obviously green. This is one reason green spaces are infrared rich, even if the sky looks blue to your eyes. A forest is not merely shade. It is a different spectral environment, often more infrared dominant, with softer high energy visible load, and with complex patterns of scattering and reflection created by leaves, bark, soil, humidity, and canopy geometry. Dirt, sand, soil, tanbark, decomposing leaves, grass, and flowers each have different absorption and reflection characteristics, and those differences matter because your biology responds to ratios and timing, not just intensity.

When you move through green spaces, you are not only getting shade. You are bathing in a reflectance signature dominated by chlorophyll and plant water. Chlorophyll absorbs visible wavelengths used for photosynthesis and reflects a large portion of near infrared, which means green landscapes become IR rich environments. In my view, this is why forests and parks often feel biologically calming and supportive. You are sitting in a spectral field that naturally feeds electron and proton current dynamics and hydration physics rather than hammering the system with high energy visible glare. There is another layer that matters. Living systems do not just absorb light, they also emit. As organisms and landscapes absorb energy and run metabolism, they release longer wavelength infrared back to the environment. One of the ranges I pay attention to is around 10,000 to 12,000 nanometers, which sits in the long wave infrared region that is strongly tied to thermal emission and environmental signalling. This is not about making it mystical. It is about recognising that the environment is a two way photonic exchange, not a one way solar download.

If you want to feel how alive the environment is, just look at how plants behave. Pollinator signalling, plant chemical responses, and even the Venus flytrap are reminders that life is continuously sensing and responding to environmental cues. Add in the mycelial networks under the soil that coordinate exchange between plants, and it becomes obvious that living systems are not passive receivers of sunlight. They are active participants in a field of information and energy. In a natural landscape, chemistry is part of the optics story. Light interacting with soil and living surfaces drives free radical dynamics, nitric oxide signalling, and a whole suite of molecular exchanges that include microRNA and other signalling packets. I am not bringing this up to make it complicated. I am bringing it up to make it accurate. The outdoor environment is a living biochemical and photonic conversation, and your body is always listening to light reflectance, scattering, temperature gradients and broadband infrared exposure.

For humans, this is where the story gets deeper than “sunlight hits skin.” Life is participating in a bidirectional relationship with the optical field. Plants respond to pollinators. Mycelial networks exchange information and resources. Chemistry in soil shifts with moisture and light. Free radical chemistry and signalling molecules change with environmental conditions. Biophotons exist as a low level biological emission, and in my view, the key idea is not to be mystical, it is to understand that organisms are continuously transforming energy and information and interacting with their surroundings. If you live inside a forest, you are inside a living optical architecture that has been shaped by evolution to support life, not to degrade it. And in these natural ecosystems like jungles and forests or nature reserves energy is abundant, conserved by living systems and shared collaboratively. A dense canopy may trap moisture and heat providing an environment well suited to growth and rapid reoperation of all sorts of organisms. Like all good engineering we attempt to design systems that work from the same principles, such as a greenhouse.

A greenhouse is a simple illustration of how optics shapes biology. Glass changes spectrum, changes convection and humidity, and changes the ratio of direct versus diffuse light. Plants still grow, but the optical and thermal environment is not identical to open sky. Infrared and water dynamics influence how charge moves through living systems. So even when photosystems are powered mainly by visible wavelengths, the infrared environment and humidity levels are shaping how the plant moves water, minerals, and charge. That is why even heat in a greenhouse is not just heat. It is part of an optical and hydration environment that changes how life functions.

The Built Environment’s Optical Problem

Now compare that to the built environment, because cities are optical interventions. Concrete, asphalt, glass, steel, and artificial lighting reshape the spectrum and the scattering environment. Asphalt and dark roofing absorb solar energy and re radiate it as heat, changing thermal gradients and shifting the infrared signature of a space. Glass blocks and filters key parts of the spectrum, especially if it is double glazed or low emissivity treated, stripping out bands that biology expects from outdoors. Indoors, much of the spectrum is missing. Ultraviolet is usually absent. A lot of infrared is depleted. And then we replace nature’s broadband light field with narrowband artificial peaks and flicker patterns that do not resemble the solar pattern that shaped our physiology. If you want to see how far from nature most people live, just list the filters. Concrete, asphalt, and glass dominate modern cities. Inside cars you are behind angled tinted glass. Indoors you are behind double glazed glass, low emissivity glass, and coated windows that block and distort key parts of the spectrum. Then we add personal filters, contact lenses, glasses, sunglasses, makeup, eyeliner, and sunscreen. Each one changes optical input again. Most people are not living in an outdoor spectrum at all. They are living in a stacked filtration environment.

Cities are optical interventions. Concrete, asphalt, glass, steel, and artificial lighting reshape the spectrum and the scattering environment in ways nature never designed us to live under. Dark surfaces like asphalt and roofing absorb huge amounts of solar energy and then re radiate it as heat, changing thermal gradients and shifting the infrared signature of the space. Glass adds another layer, especially double glazed and low emissivity treated windows, which block and filter key parts of the spectrum and strip out bands biology expects outdoors. Step inside and you are immediately missing major pieces, ultraviolet is largely absent, a lot of infrared is depleted, and the broadband solar pattern is replaced by narrowband artificial peaks and flicker patterns that do not resemble the light field that shaped our physiology.

If you want to see how far from nature most people live, just list the stacked filters. In cities, you are surrounded by concrete, asphalt, and glass. In cars, you sit behind angled tinted windows. Indoors, you are behind coated glass and engineered materials that further distort spectrum and timing. Then we add personal filters, contact lenses, glasses, sunglasses, makeup, eyeliner, sunscreen, each one changing optical input again. The result is not just less sunlight, it is a layered filtration environment that progressively disconnects people from the real outdoor spectrum.

Cars layer on even more distortion. Tinted windows, angled glass, and enclosed reflective surfaces change both spectrum and intensity. Then add contact lenses, glasses, sunglasses, makeup, eyeliner, sunscreen, and you have multiple optical filters stacked on top of an already filtered world. People think they are living in “the same world” but with less sun. They are not. They are living in a different optical reality.

This is why sunrise and sunset rituals are not just spiritual. They are optical alignment practices. Facing east at sunrise and west at sunset is not about romance. It is about receiving the day’s cleanest timing signal with minimal interference. Direction matters because the sky behind you can carry a different spectral weighting. If you want the most coherent signal, orient to the source. And if you really want to do it properly, do it grounded in a quiet natural setting, away from artificial light and heavy electrical fields, so the signal is not competing with noise. The environment is not just light, it is also the field conditions that shape how biology interprets that light. This directional nuance people often believe doesn’t’ matter, but it does. At sunrise, orienting east makes sense because you are aligning your eyes with the changing spectral gradient and the earliest timing signal. At sunset, orienting west matters because you are tracking the declination where infrared remains present longer while UVB has already dropped out and UVA is fading. If you face away from the setting sun, you can end up looking into a sky field that can feel more blue dominant relative to the solar direction. That is not the signal you want late in the day if your goal is nervous system downshifting. Light is only one layer. Where you do sunrise and sunset matters too. A quiet forest setting matters, grounding matters, and geology matters. Places near water, volcanic regions, artesian water, and areas with better magnetic flux can change how the entire system feels because biology is interpreting light inside a field environment. If you want to do the simple rituals properly, choose places where the environment is clean, quiet, grounded, and geologically alive.

Humans also evolved with firelight. Fire extended our days. It technically breaks circadian rhythm rules, but it is a break we have had time to partially adapt to because fire is mostly red and infrared, low intensity, and low in blue. Candlelight, dim lamps, and warm light at night are not the same as bright overhead LEDs or screens. They do not provoke the same melatonin suppression and cortisol excitation when used responsibly. Still, the best move remains simple. Follow nature when you can, and when you cannot, mimic the spectrum and intensity that nature used.

At night, the moon matters. It provides a low lux level of illumination that can be biologically meaningful, especially around the full moon when nights can be bright enough to change behaviour and sleep depth in sensitive people. Stars provide an even smaller lux level, but the point is not to romanticise it. The point is to understand gradients. Night is not an on off switch. It is a spectrum of low light environments, and biology is tuned to read those gradients. The moon also tracks with tides and has long been linked with reproductive rhythms and wakefulness cycles across species. Even if you debate the strength of each effect, the core truth stands: nocturnal optics are part of the living system.

When you step back, you realise the optics of the planet are not a footnote to biology. They are a foundational language. Spectrum, power density, angle of incidence, scattering, reflection, humidity, altitude, latitude, and seasonality are shaping how organisms harvest energy and how they time repair. The body is clever. It can capture energy on one surface area and distribute benefits systemically through circulation, neural signalling, hormonal cascades, and water based coherence. But there is still something unique about UV touching the skin directly because UV triggers photochemistry that visible light alone cannot replicate. This includes nitric oxide release, vitamin D synthesis, neurohormonal cascades, and the activation of key UV sensitive molecules, including aromatic amino acids and other chromophores. UV on skin also interfaces with cholesterol, melanin, and a host of signalling systems that move far beyond the skin surface. That is why the goal is not to fear UV or chase it recklessly. The goal is to understand earth’s planetary optics and meet the light environment intelligently, with respect for ratios, timing, latitude, season, and the realities of modern life, supplementing the best approximation of a natural optical setting wherever possible.

Key Takeaways

• The light environment is a planetary optical field, not just a direct solar beam plus a clock app.
• Humidity and water vapour reshape infrared delivery because water absorbs strongly above certain wavelengths, changing what reaches the ground. But once the light reaches organisms on earth and reflectance and refraction come into play, longer wavelengths than 2,500nm are experienced, especially when the introduction of fire and body-heat biophotons are present.
• At altitude, thinner air and often lower moisture can shift spectral ratios and increase intensity, including more shortwave energy in the UV, purple and blue wavelengths.
• Sunrise and sunset are naturally red and infrared dominant with lower direct UV power density because the optical path is longer, but the blue, purple and UV Rayleigh scattering is ever present giving a daylight optical environment with blue always balanced by red and infrared.
• UVA becomes more directly available around 10 to 15 degrees of solar inclination, and UVB becomes directly available around 30 degrees when inclining, then UVB drops out below 30 degrees when declining, directly from the sun but not absent from the planet optically. This is vital to remember because the planetary optics have not been considered in most lighting/architecture/engineering/technology models.
• The sky is a light source, and you can receive UV and high energy visible through scattering even when the sun is not directly on you.
• You can tan without facing the sun directly because scattered and reflected photons still reach exposed skin.
• Green spaces are infrared rich because chlorophyll reflects near infrared strongly, changing the spectral environment compared with concrete and asphalt.
• Sand, snow and water amplify high energy visible and UV exposure through reflection, which is why beach glare can be a major optical load for photophobic sensitive people.
• Northern and southern hemispheres have opposite seasons, so you can go summer to summer if you want consistent high solar elevation and stronger UV presence while rebuilding health.
• The built environment changes the spectrum twice, first by blocking and filtering sunlight through glass and walls, then by replacing missing bands with narrowband artificial peaks in blue wavelengths and lacking broadband infrared.
• UV on skin is uniquely important because it triggers photochemistry that visible light alone does not replace, including nitric oxide release, vitamin D synthesis, and neurohormonal signalling. Simply just being outside underneath the blue sky in any season can afford you some level of UV photon access so essential for optimal health. 

All-Cause Mortality Lowered by Sunlight Exposure

Included below are numerous studies, including meta-analysis showing all-cause mortality reduction with higher levels of ultraviolet sunlight exposure via the 25 Hydroxy Vitamin D serum testing. So high Vitamin D and strong sunlight are clearly markers and environments worth considering if you’re looking to lower your risk of death by any cause.

A growing number of cardiologists are realizing that hypercholesterolemia is relatively rare and 99% of people do not have mutations predisposing them to this condition. They are also realising the role of chronic inflammation and high triglycerides as key risk factors in a build-up of small dense LDL (sdLDL) and hence an increased risk of plaque buildup, atherosclerosis, cardiovascular disease and all other heart and blood conditions. Now that more cardiologists are testing hsCRP, sdLDL and Triglycerides along with HDL and LDL and using ratios to trend these results in patients, the prescriptions of statins should reduce. Proper testing and lifestyle management of individuals over the age of 50 is fast becoming the more reasonable path forward under the guide of your family doctor/general practitioner and/or specialist MD.

At BioSpectral Systems, we are connected with some of the most forward-thinking cardiologists who have been practicing this way for decades as they have kept up with the latest research papers in their specialty, reforming their scientific opinion as the science moves into greater levels of understanding around heart disease and related conditions.

Studies you can read about All-cause mortality being reduced by sunlight exposure

1. http://ar.iiarjournals.org/content/38/2/1173.full

2. https://www.outsideonline.com/2380751/sunscreen-sun-exposure-skin-cancer-science 

3. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4103214/

4. https://www.medscape.com/viewarticle/748744

5. http://www.liveinthenow.com/article/vitamin-d-shown-to-lower-all-cause-mortality-by-nearly-thirty-percent

6. https://www.bmj.com/content/348/bmj.g3656

7. https://www.vitamindcouncil.org/large-meta-analysis-suggests-high-vitamin-d-status-reduces-all-cause-mortality/#.XJtNjYrQiUk

8. https://academic.oup.com/jcem/article/102/7/2136/3764364

9. https://vitamindwiki.com/Vitamin+D+and+mortality+a+meta-analysis+of+RCT+-+2008 – Vitamin D supplementation

10. https://www.medicalnewstoday.com/articles/278323.php\

11. http://www.odin-vitd.eu/files/VitD&mortality%202017.pdf

12. A large study using the UK Biobank cohort found that vitamin D deficiency and insufficiency were strongly associated with all mortality outcomes. Regular vitamin D supplement users had 10% lower all-cause mortality, and 11% and 29% lower cancer and respiratory disease mortality, respectively. https://pubmed.ncbi.nlm.nih.gov/36208176 

13. Avoidance of sun exposure is a risk factor for all-cause mortality: results from the Melanoma in Southern Sweden cohort. https://pubmed.ncbi.nlm.nih.gov/24697969 

14. The European Society for Clinical and Economic Aspects of Osteoporosis and Osteoarthritis (ESCEO) has stated that desirable 25(OH)D levels for optimal risk reduction in mortality have been explored in several epidemiologic studies, most of which suggested a continuous inverse relationship between increasing values of 25(OH)D and a lower risk of mortality. https://pubmed.ncbi.nlm.nih.gov/28390010 

Studies you can read about the many benefits of sunlight

1. The importance of UV light in human health - https://academic.oup.com/endo/article/159/5/1992/4931051?fbclid=IwAR1JlJH_kQoSkQNn5lC8S2liPPCv5gtym8VNMHT8MdZ5FjsH5uRzSUSjzFg

2. The sun is healthy, makes you thinner, lowers blood pressure, etc - • http://www.dailymail.co.uk/health/article-3570267/New-research-reveals-sun-benefits-AREN-T-linked-vitamin-D.html

3. Low Vitamin D is associated with All-Cause-Mortality - https://www.researchgate.net/publication/259355114_Meta-Analysis_of_Long-Term_Vitamin_D_Supplementation_on_Overall_Mortality

4. Avoidance of the sun and use of sunscreen are the likely main reasons for low Vitamin D - https://www.sciencedaily.com/releases/2017/05/170501102258.htm 

5. Sunscreens that block only UVB could result in reduction in vitamin D production after prolonged exposure, or even a destruction of vitamin D that has just been formed - https://pubmed.ncbi.nlm.nih.gov/27286277/ 

6. UVB light is important for eye health and tanning to protect against skin cancer - https://www.sciencedirect.com/science/article/pii/S0022202X15301160