The Human Operating Manual

Sunlight Exposure

Sunlight Exposure

Why Sunlight is Essential

The Benefits of Sun Exposure

As mentioned in the Sleep & Circadian Rhythm Basics section, sunlight provides essential cues to the eyes and as a consequence, the brain (suprachiasmatic nucleus), that regulate the timing of the circadian rhythm by inhibiting the production of melatonin. Melatonin is the sleep hormone and a powerful antioxidant that helps to conduct many repair processes in the brain and body. If you inhibit melatonin secretion because of blue light at night, then you’re going to lower growth hormone, which makes it more difficult for you to burn fat and build muscle, and you’ll also prevent the brain from clearing out the toxins that get accumulated there during the day. The reality is much more complex than this, but our bodies essentially prepare to perform bodily maintenance during periods of low light and to increase physical activity during periods of sunlight.

By going outside and allowing our bodies to soak up the sunlight, we are able to produce adequate levels of vitamin D3 (promotes strong bones, regulates the immune system, inhibits some forms of cancer, prevents autoimmunity issues and symptoms, helps to manage diabetes, and lower risk of heart disease), build melanin levels to establish sun radiation tolerance for the summer (reducing the chances of getting burnt), decrease stress levels, and to tell the brain when to prepare for sleep. Not to mention the more commonly known effect of producing more serotonin and reducing seasonal affective depression disorder symptoms.       

The Negative Health Effects of Not Getting Exposure

As you would expect, the symptoms of not getting enough sunlight are the opposite of the benefits of catching rays. To put it simply, if you spend too much time inside you might mess with your circadian rhythm, not be able to get adequate and high-quality sleep, stress levels will elevate, infection and sickness risk will increase, bone density will decrease (leading to osteoporosis), you may get some sort of calcification issue down the line (due to leaching calcium from the bones or excess calcium in the diet without vitamin D3 to utilize it), autoimmunity diseases may arise, depression symptoms increase, heart disease risk and diabetes risk will increase, etc. Then there’s the increased chance of getting burnt when you actually go out one day. This is the typical response when people spend 9 months of the year indoors and then go out to the beach on a scalding hot day.

The unfortunate consequence of demonizing the sun as being the cause of melanoma, is the belief that we need to avoid it at all costs (unless wearing your vitamin D synthesis blocking sunscreen). Regardless of the lack of scientific data in support of this claim. There have been studies suggesting excessive sun exposure increasing the risk of getting less serious basal and squamous cell carcinomas, but the case for melanoma has fallen flat as of late. In fact, it appears that those who have the most sun exposure of all (those with solar elastosis) are the least at risk for developing melanoma.    

UV Radiation and Vitamin D

The Effects of UVB and UVA

We avoid UVB and UVA light, eliminating the response to light that triggers vitamin D production. We need vitamin D for amyloid protein buildup, blood sugar regulation, and setting the circadian rhythm. Red and near infrared (felt as heat) light seems to prepare cells to harness the power of UV rays to produce vitamin D, while protecting themselves from UV light damage, and recovery after the fact.

Vitamin D Conversion from Sunlight

 Its synthesis requires exposure to UVB light and heat. 7-dehydrocholesterol (a molecule found primarily in the skin’s epidermal layer) reacts to UVB light and forms pre-vitamin D, a precursor form, which spontaneously converts to cholecalciferol (vitamin D3).

Cholecalciferol is then transported in the blood to the liver via the vitamin D binding protein. It then forms 25-hydroxyvitamin D (25(OH)D otherwise known as calcidiol), which is the major circulating form of vitamin D. In a final step, 25(OH)D travels to the kidneys where it forms 1α,25-dihydroxyvitamin D (1,25(OH)2D also known as calcitriol), which is the active steroid hormone. The conversion to 1,25(OH)2D is regulated by feedback mechanisms involving concentrations of 1,25(OH)2D, parathyroid hormone, calcium, and phosphate.

Food Sources of Vitamin D

Vitamin D3 (cholecalciferol) can be found in fortified dairy products and fish oils, or synthesized in the skin from 7-dehydrocholesterol by ultraviolet irradiation. The vitamin D produced by 7-dehydrocholesterol depends on the intensity of UV irradiation (UVB sunlight), which varies with season and latitude. In order to be biologically active, affect mineral metabolism, inhibit the growth of cancer cells, and protect against certain immune mediated disorders, vitamin D most be converted to its active form. Vitamin D is then transported in the blood, by the vitamin D binding protein (DBP), to the liver. 

Ultraviolet (UV) Light Effects

UVC light (100-280 nm) is the most dangerous form of sunlight radiation, but is mostly absorbed by the ozone layer. 

UVB light (280-315 nm) is the wave length generally considered to be a major risk factor for basal cell and squamous cell carcinomas (the much rarer and more dangerous melanoma has been greatly debated as not being correlated). In saying that, we need UVB radiation to synthesize vitamin D from the sunlight. Which raises the issue of being told that sunblock (which blocks UVB radiation) is necessary to avoid dying of melanoma, whereas the health effects of not getting enough vitamin D also result in a much longer list of worsening health risks. UVB radiation mostly gets absorbed by the earth’s ozone layer, resulting in differing levels of radiation depending on the geography of the planet.

In my opinion, it is much more likely that our lack of sun exposure (hiding indoors all year) has reduced our melanin production to an extent where we are completely defenseless against sudden exposure during the summer months. Meaning that our fear of skin aging and dying of skin cancer has actually resulted in reinforcing our fears, cancer risk, and backing the propaganda that we require sunblock to survive. It would be much more advantageous to build up UV resistance by progressively increasing our exposure, preventing excessive burning and improving vitamin D synthesis. Sun exposure is a form of hormesis and all stressors work as an inverse-U-shaped curve. A small amount of stress is okay, a medium amount is optimal, but large amount is detrimental.  

UVA light (315-400 nm) makes up most of the UV radiation that penetrates our skin. It is known for its immediate tanning effect and has also been known to increase the risk of skin cancers. UV also promotes nitric oxide (NO) production, which reduces your blood pressure. UVA-induced NO, in particular, can have an antimicrobial effect.

UV radiation levels are greater when the sun is at its highest point during the summer, closer to the equator, at a higher altitude, in reflective areas like snow, and in places and times when ozone levels are low.   

Why We Don’t Get Enough Sunlight

  • Conditioned to be afraid of being burnt (sunblock industry). Skin cancer and the lack of gradual seasonal exposure resulting in burns.
  • Always inside (technology use, office jobs).
  • Too cold because we are always clothed (too comfortable).
  • Genetic exceptions (fair skinned not being able to handle high doses vs. high melanin content individuals requiring more)

How to Get Your Daily Dose of Sun

  • Eye exposure in the morning, midday for vitamin D conversion, late afternoon/night for wind down.
  • A 20-minute walk first thing in the morning, a lunchtime walk or exercise in the park, a post-prandial walk in the afternoon 
  • Gradual exposure while approaching summer to build melanin levels and tolerance.  
  • Try to avoid mixing your light cues by turning off blue-light emitting sources (cell phone, tv, computer, LED lights) 2-4 hours before bed time

More Extreme Ways of Utilizing Light Therapy (Boundless)

Ways to reduce aging light sources:

  • Starting at 8am, dim lights in the house. Switch to red LEDs or candles.
  • If you can’t install dimmers, wear glasses that filter blue light.
  • Go outside for 10-20 minutes a day to get adequate UV light exposure. Do it before the sun hits its peak and you won’t need sunscreen.

The Visible Light Spectrum

Blue light (450-495 nm):

Suppresses melatonin and low melatonin leads to poor sleep and increased cancer risk. However, it is essential for setting the circadian rhythm and encouraging wakefulness during the day. Excess blue light can also cause inflammation and mitochondrial dysfunction, primarily because of its impact on glucose control. In the evening, exposure to blue light causes a peak in glucose levels, leading to higher blood sugar and an increase in insulin resistance. It has antibacterial properties, boosts wakefulness, increases alertness, and can adjust the circadian clock. Too much blue light at the wrong time can damage your mitochondria, promote insulin resistance, cause insomnia, depression, and increase inflammation. Blue light exposure at night and circadian mismatches are linked to many types of cancer, diabetes, obesity, heart disease, and Alzheimer’s.

Red/Infrared Light (620-750 nm):

Humans have such a long history with fire that our pineal glands are well equipped to encounter red, fire-spectrum light well past sundown, without negative consequences for sleep.

Red/infrared therapy uses these red and infrared wavelengths to restore, repair, and protect tissue that is injured, degenerating, or at the risk of dying by activating stem cells that normally become latent as we age, while improving mitochondrial function. Increasing the amount of energy mitochondria can produce. It also improves levels of NO, which ensures your cells are nourished by oxygen, blood, and nutrients.

Infrared light therapy also helps to create exclusion zone (EZ) water, the type of water in your cells. Without enough of this water, your cells become dehydrated and mitochondria stop functioning as well. Drink raw vegetable juices, fresh spring water, or glacial meltwater. Infrared light causes EZ water to spontaneously form in your cells, boosting mitochondrial function.

Also effective at treating muscle fatigue and injuries. More stem cells mean replacing old cells, more mitochondrial function means less inflammation, and an increase in exercise and circulation means preventing cell loss.

Wavelengths of 630-670nm (red) and 810-880nm (infrared) are the most effective for healing. Light at these wavelengths penetrate up to 8-10mm into the skin and affect your cells at a biochemical level. Red light can decrease inflammation, improve skin tone, repair sun damage, fade scars and stretch marks, promote hair growth, and stimulate collagen production in the skin. Also, healing wounds and age-related macular degeneration.

Spending time in a sauna (infrared or not) also leads your body to produce heat shock proteins, which prevent protein degradation caused by oxidative stress. HSPs scavenge free radicals, boost glutathione levels, and make sure proteins retain their proper structure.

Yellow Light (570-620 nm):

Increases your mitochondria’s ability to produce ATP, but it doesn’t penetrate as deeply as red or infrared light. Usually used to treat skin conditions and damage from too much sun exposure. Increase collagen, reduce hyperpigmentation, reduce fine lines and wrinkles, speed healing, and smoother skin.

Intravenous Laser Therapy:

Stresses your cells to produce a hormetic strengthening response. Studies have shown it to reduce inflammation, boost mitochondrial efficiency, and stimulate the production of more ATP. It also produces a huge wave of activated vitamin D3, far more than the sun can achieve.

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