Every day the sun rises up giving life-sustaining light to this planet earth. Throughout ancient history the sun has been worshiped by many civilizations as a god of medicine and well being that can bring sickness as well. We all know that the sun’s Ultra Violet Radiation (UVR) enhances our general feeling of well-being.
Sunlight is a key factor in photosynthesis, the process used by plants and other autotrophic organisms to convert light energy, normally from the Sun, into chemical energy that can be used to synthesize carbohydrates and to fuel the organisms’ activities.
Modern science also recognized the danger of too much exposure to the Ultraviolet light to our skin. But how much sunlight do we actually need or when is the right time to get the sun or what is the right balance?
Understanding Ultraviolet Radiation
Knowing the basics of Ultraviolet (UV) Radiation and how it affects your skin is the first step to reduce the danger from sun radiation. UV radiation is part of the natural energy produced by the sun.
Two types of UV light are mainly responsible for all kinds of risk associated with the sun:
- Ultraviolet A (UVA) has a longer wavelength and linked with skin aging. It was thought to be less damaging to DNA, However, UVA is now known to cause significant damage to DNA via indirect routes (formation of free radicals and reactive oxygen species), and can cause cancer.
- Ultraviolet B (UVB) has a shorter wavelength than visible light that is why your eyes can’t see it but your skin can feel it. UVB directly damages DNA and causes sunburn. It is a requisite for both vitamin D3 synthesis and a mutagen.
Some UV radiation is essential to the body as it stimulates blood circulation and the production of vitamin D. The World Health Organization (WHO), recommended sun’s UV radiation exposure to treat rickets, psoriasis, eczema, jaundice and acne. Dermatologists can advise whether sunlight treatments will suit your particular skin condition.
Compared to fair-skinned people, dark-skinned people have a much lower risk of developing melanoma or non-melanoma skin cancers. They do not normally have to apply sunscreens and can safely tolerate relatively high levels of UV radiation without getting burnt. But – regardless of skin color – the risk of eye damage and of harmful effects on the immune system remains.
Vitamin D production
Sunlights ability to produce vitamin D in our body is one of the most well-known benefits of the sun. Lack of exposure to the sun is directly linked with vitamin D deficiencies. When sunlight hits the skin, there’s certain chemical reactions happen that generate vitamin D (also known as “the sunshine vitamin”) from cholesterol in your skin. Sun’s Ultraviolet B (UVB) rays hit cholesterol in the skin cells, generating the energy for vitamin D synthesis to occur.
The efficiency of vitamin D production depends on the number of UVB photons that penetrate the skin, a process that can be curtailed by clothing, excess body fat, sunscreen, and the skin pigment melanin. A 2008 study finds that exposing to the sun wearing a swimsuit for a 30-minute period, people will make the following amount of vitamin D in their body:
- 50,000 International Units (IUs) in most Caucasian people
- 20,000 to 30,000 IUs in tanned people
- 8,000 to 10,000 IUs in dark-skinned people
The main physiologic function of vitamin D involved in calcium metabolism, neuromuscular transmission, bone mineralization and immune system functioning. Vitamin D enhances calcium and phosphorus absorption, controlling the flow of calcium into and out of bones to regulate bone-calcium metabolism. Vitamin D maintains serum calcium and phosphorous levels within the normal physiologic range to support most metabolic functions.
Many experts daily recommendation: 4000 IU vitamin D3 without sun exposure or 2000 IU plus 12-15 minutes of the midday sun. Except for sun-sensitive individuals or those on medications that increase photosensitivity. A natural vitamin D dietary supplement can supply enough for the body’s requirements.
According to Gilchrest, some sunlight enters the skin even through a high-SPF sunscreen, so people can maximize their dermal vitamin D production by spending additional time outdoors while wearing protection. Without the sunscreen, this same individual would be incurring substantially more damage to his/her skin but not further increasing her vitamin D level.
Affects hormone production
From the sun’s rays and through the retina of your eye creates a chemical conversion into an increasing amount of serotonin hormone production that substantially uplifts your mood, feels calm and focused. There’s a reason why you feel much better when you are out in the sun. Away from the sun for a long time really can make you feel depressed. Sun also affects the production of the hormone melatonin. Sunlight reduces melatonin and wakes you up. Darkness stimulates melatonin and helps you sleep.
Treats major depressions and mental disorders
The right exposure to the sun is used as light therapy to help people with major depression related to changing seasonal pattern (also known as a seasonal affective disorder or SAD), premenstrual dysphoric disorder (PMDD), pregnant people with depression, anxiety-related disorders, panic attacks and other major depressions and mental disorders.
Prevents the growth of some deadly bacteria, viruses, and microbes
The heat and the humidity generate from the sun reduces the production of many harmful viruses (such as Influenza and COVID-19) that affects our well being. That’s another reason you are more healthy during the summer. The UV (Ultra Violet) rays also have antibacterial effects and prevent the growth of some deadly bacteria (such as tetanus, Typhoid, TB, Staph, Strep) and microbes. The Infrared wavelength of the sun boosts your immune system thus helps heal the wound, decrease pain and increases the resistance to infection.
Cancer and UV lights
Although excessive exposure to the sun’s UV rays is an established risk factor for the three main forms of skin cancer— malignant melanoma, basal cell carcinoma, and squamous cell carcinoma. Continued high sun exposure was linked with increased survival rates in patients with early-stage melanoma. It was evident that most melanomas occur on the least sun-exposed areas of the body, and occupational exposure to sunlight reduced melanoma risk. (1)
A moderate amount of sunlight actually has preventive benefits when it comes to cancer. People who live in areas with fewer daylight hours are more likely to have some specific cancers than those who live where there’s more sun during the day. These cancers include colon cancer, Hodgkin’s lymphoma, ovarian cancer, pancreatic cancer and prostate cancer. (2)
Some impressive health links
Without sufficient vitamin D, bones will not form properly. In children, this causes rickets, a disease characterized by growth retardation and various skeletal deformities, including the hallmark bowed legs. More recently, there has been a growing appreciation for vitamin D’s impact on bone health in adults. Low vitamin D levels will precipitate and exacerbate osteoporosis in both men and women and cause painful bone disease osteomalacia.
There is substantial (not definitive) evidence that suggests high levels of vitamin D either from diet or from UVR exposure may decrease the risk of developing multiple sclerosis (MS). Populations at higher latitudes have a higher incidence and prevalence of MS. A review in the December 2002 issue of Toxicology by epidemiology professor Anne-Louise Ponsonby and colleagues from The Australian National University revealed that living at a latitude above 37° increased the risk of developing MS throughout life by greater than 100%.
As with MS, there appears to be a latitudinal gradient for type 1 diabetes, with a higher incidence at higher latitudes. A Swedish epidemiologic study published in the December 2006 issue of Diabetologia found that sufficient vitamin D status in early life was associated with a lower risk of developing type 1 diabetes.
A Finnish study published 3 November 2001 in The Lancet showed that children who received 2,000 IU vitamin D per day from 1 year of age on had an 80% decreased risk of developing type 1 diabetes later in life, whereas children who were vitamin D deficient had a fourfold increased risk. Researchers are now seeking to understand how much UVR/vitamin D is needed to lower the risk of diabetes and whether this is a factor only in high-risk groups.
People living at higher latitudes throughout the world are at higher risk of hypertension, and patients with cardiovascular disease are often found to be deficient in vitamin D, according to research by Harvard Medical School professor Thomas J. Wang and colleagues on the 29 January 2008 issue of Circulation. There is an inflammatory component to atherosclerosis, and vascular smooth muscle cells have a vitamin D receptor and relax in the presence of 1,25(OH)D, suggesting a multitude of mechanisms by which vitamin D may be cardio-protective.
How much is the excessive exposure of Ultra-Violet Radiation?
Depending on how sensitive your skin is to sunlight, aim to get 10-30 minutes midday sunlight several times per week. To maintain healthy blood circulation and vitamin D, people with darker skin may need more sun exposure than light-skinned people.
You can enjoy all kinds of outdoor activities taking some simple and smart protective measures (e.g., head cover, polaroid sunglasses, Sunscreen). Unprotected exposure to both UVA and UVB damages the DNA in skin cells, producing genetic defects, or mutations, that can lead to skin cancer (as well as premature aging). These rays can also cause eye damage, including cataracts and eyelid cancers.
To avoid sunburn choose a sunscreen that protects against both UVA and UVB rays with an SPF of 15 or higher. Apply about 15 to 30 minutes before going outside, then reapply every two hours. But if you’re going to be outside for more than 15 minutes, it’s a good idea to protect your skin. You can do that by applying sunscreen with a sun protection factor (SPF) of at least 15. Wearing a protective hat and shirt can also help.