Sun exposure

Hallmarks of high cumulative sun exposure in whites are coarse wrinkles, actinic keratoses, telangiectasias and actinic lentigines (‘age spots’), features known as photoaging.

The ultraviolet radiation in sunlight has both positive and negative health effects.

It is a principal source of vitamin D3 and a mutagen.

The sun is a potent stimulus to vitamin D production.
The sun in small/moderate amounts benefits numerous systems such as the endocrine, musculoskeletal, immune systems and promoted circadian rhythms and sleep patterns, and cushions against disturbances in mood.
Sunlight in large amounts and or with direct exposure can be harmful by causing sunburn, skin senescence, and skin cancer, in large part,  because of its content of ultraviolet radiation.

The adverse effects of ultraviolet radiation are the cellular generation of reactive oxygen species, damage to lipid bilayers, and cellular macromolecules such as DNA, and immune suppression.

UV exposure has positive effects for endorphin levels, and possibly for protection against multiple sclerosis.

Visible sunlight to the eyes gives health benefits:through its association with melatonin synthesis, maintenance of circadian rhythms, and reduced risk of seasonal affective disorder.

Long-term sunlight exposure is associated: with development of skin cancer, skin aging, immune suppression, and eye diseases such as cataracts and macular degeneration.

Short-term overexposure causes: sunburn, snow blindness, and solar retinopathy.

UVB radiation with a wavelength of 290–315 nanometers penetrates skin and converts cutaneous 7-dehydrocholesterol to previtamin D3, which in turn becomes vitamin D3.

UVB radiation does not penetrate glass, so exposure to sunshine indoors through a window does not produce vitamin D.

Factors affecting UV intensity and vitamin D synthesis include: time of day, time of year, geographic latitude, ground altitude, cloud cover, smog, skin melanin content, and sunscreen are among the factors that greatly affect UV intensity and vitamin D synthesis,

Adequate amounts of vitamin D can be produced with moderate sun exposure to the face, arms and legs, averaging 5–30 minutes twice per week without sunscreen.

The darker one’s complexion, or the weaker the sunlight, the more minutes of exposure are needed to produce vitamin D.

For adequate vitamin D production sun exposure approximates 25% of the time for minimal sunburn.

Vitamin D overdose is impossible from UV exposure, as the skin reaches an equilibrium where the vitamin degrades as fast as it is created.

Studies show lower rates of death from cancer and cardiovascular diseases in regions with greater sun exposure than in areas with less sun exposure.

Vitamin D levels are demonstrated with a serum 25(OH)D3, calcifediol) test.

Facial skin provides little vitamin D3.

Three benefits of UV exposure are production of vitamin D, improvement in mood, and increased energy.

UVB induces production of vitamin D in the skin at rates of up to 1,000 IUs per minute.

Vitamin helps to regulate calcium metabolism essential for the nervous system and bone health, immunity, cell proliferation, insulin secretion, and blood pressure.

Most people in the world depend on the sun to get vitamin D.

Colon cancer mortality in the US is inversely correlated with solar radiation.

A Canadian study found the risk of developing breast cancer in women is markedly reduced if those women who is the most sun exposed in the second decade of life (Garland CF).

Increased sun exposure, living it lower latitudes, and having higher 25 (OH)D levels, have been associated with improvement and cardiovascular health and reduced risk of cardiovascular mortality.

If people cannot get sunlight, then they will need 1,000 IU of vitamin D per day to stay healthy.

Eating oily fish three or four times per week will provide enough vitamin D from that food source alone.

People with higher levels of vitamin D tend to have lower rates of diabetes, heart disease, and stroke and tend to have lower blood pressure.

However, vitamin D supplementation does not improve cardiovascular health or metabolism, so the link with vitamin D must be in part indirect.

People who get more sun are generally healthier, and also have higher vitamin D levels.

It has been found that ultraviolet radiation produces nitric oxide in the skin, and nitric oxide can lower blood pressure.

People who stay inside most of the time have low vitamin D levels.

Getting enough vitamin D can help lower the risk of autoimmune diseases, cardiovascular disease, types of cancer, dementia, types 1 and 2 diabetes mellitus, and respiratory tract infections.

Fetuses and children who do not get enough vitamin D can suffer from growth retardation and skeletal deformities.

Sun exposure associated with lower prevalence of multiple sclerosis, as it is least prevalent in the sunniest regions.

Ultraviolet-B radiation exposure of sunlight appears to be most important and this may operate via vitamin D synthesis.

Ultraviolet (UV) irradiation present in sunlight is an environmental human carcinogen.

The toxic effects of UV from natural sunlight and therapeutic artificial lamps can occur.

The major acute effects of UV irradiation on normal human skin comprise sunburn inflammation erythema, tanning, and local or systemic immunosuppression.

Malignant melanoma, is mostly caused by indirect DNA damage from UVA radiation.

UVC is the highest-energy, most-dangerous type of ultraviolet radiation, and causes adverse effects that can be mutagenic or carcinogenic.

Broad-spectrum UV radiation is a carcinogen whose DNA damage is thought to contribute to most of the estimated 1.5 million skin cancers and the 8,000 deaths due to metastatic melanoma that occur annually in the United States.

The World Health Organization reports sunbeds are responsible for over 450,000 cases of non-melanoma skin cancer and over 10,000 cases of melanoma every year in the U.S., Europe, as well as Australia.

It is the lifetime cumulative UV exposure to skin that is responsible for significant age-associated dryness, wrinkling, elastin and collagen damage, freckling, age spots and other cosmetic changes.

Photoprotective measures be taken, including the use of sunscreen, when exposed to the sun.

Short-term over-exposure causes the pain and itching of sunburn, which in extreme cases can produce more-severe effects like blistering.

The UV index can be used as a guide to the public of dangers from over-exposure to sunlight, especially at noon, when direct sunlight is at its most intense.

Light to the eyes is important for the initiation and maintenance of circadian rhythms.

Exposure to sunlight in the morning leads to earlier melatonin onset in the evening and makes it easier to fall asleep, effective against insomnia, premenstrual syndrome and seasonal affective disorder.

Prolonged exposure to sunlight, especially intense ultraviolet light, may be linked to cataracts.

High levels of visible light may be linked to macular degeneration.

Over-exposure to sunlight can cause snow blindness, analogous to sunburn of the cornea, or can cause solar retinopathy, which is long-lasting retinal damage and vision impairment from sungazing.

Frequent exposure to the sun can cause yellow cornea.

Leave a Reply

Your email address will not be published. Required fields are marked *