UV Radiation and Your Skin

Your skin has 3 layers:
  • The epidermis, the outermost layer of skin, provides a waterproof barrier and creates our skin tone.
  • The dermis contains tough connective tissue, hair follicles, and sweat glands.
  • The deeper subcutaneous tissue, or hypodermis, is made of fat and connective tissue.
One of the most beneficial things that your skin does for you is protect you from harmful ultraviolet radiation from the sun!
Your skin forms a protective barrier against germs and injuries from the environment. It is your largest organ and shields your body against heat, light, injury, and infection. Your skin also helps regulate body temperature, gathers sensory information from the environment, stores water, fat, and vitamin D, and plays a role in the immune system protecting you from disease.
Our sun is a source of energy across the Electromagnetic Spectrum, and its radiation bombards our atmosphere constantly. Electromagnetic energy travels in waves and spans a broad spectrum from very long radio waves to very short gamma rays. The human eye can only detect a small portion of this spectrum called visible light. 
Ultraviolet, or UV, radiation is also part of the natural energy produced by the sun. On the electromagnetic spectrum, UV light has shorter wavelengths than visible light, so your eyes can’t see UV, but your skin can feel it.
UV radiation is classified into 3 primary types:
  • UVA has a longer wavelength. These rays can cause skin cells to age and can cause some indirect damage to cells’ DNA. UVA rays are mainly linked to long-term skin damage such as wrinkles, but they are also thought to play a role in some skin cancers. The A in UVA is for Aging.
  • UVB has a shorter wavelength. These rays can damage the DNA in skin cells directly, and are the main rays that cause sunburn. They are also thought to cause most skin cancers. The B in UVB is for Burning.
  • UVC is blocked by the earth’s atmosphere and therefore does not reach the skin.
The amount of UV light the skin comes into contact with depends on many factors, such as the time of day, the season, altitude and geographical location. During times of intense UV radiation, for example midday on a hot summer’s day, it is advisable to wear protective clothing and sunscreen when going out doors.
Residents of Colorado have the highest UV exposure in the country due to our high elevation, lack of protective atmosphere, +300 days of sunshine every year, and love for the outdoors. Tourists visiting Colorado's ski resorts receive up to 80% additional ultraviolet radiation as it reflects off the snow.
Too much exposure to ultraviolet or UV radiation can cause sunburn, premature skin aging, damage to the eyes, a weakened immune system, photoallergic and phototoxic reactions, and even skin cancer. The UV rays are able to penetrate the outer skin layers and pass into the deeper layers, where they can damage the cells' DNA. Skin cells with damaged DNA can replicate and, depending on each individual's genetic make-up, become cancerous. 
Most skin cancers are a result of exposure to the UV rays in sunlight and man-made sources of UV like indoor tanning beds. Both basal cell and squamous cell carcinomas (the most common types of skin cancer) tend to be found on sun-exposed parts of the body, and their occurrence is typically related to lifetime sun exposure. The risk of melanoma, the most serious type of skin cancer, is also related to sun exposure, although perhaps not as strongly.