It's no secret: overexposure to the sun causes skin damage, which can lead to the development of skin cancer. This you know. But fewer people are likely to understand how the sun damages skin. It all begins with UV radiation
What is UV Radiation?
Light travels in waves some light waves have frequencies that are visible to the human eye. When these rays hit an object, some frequencies are absorbed, others reflected. The reflected light creates the colors of everything you see (remember ROYGBIV?).But with these visible light wave frequencies travel invisible light waves, ones that are absorbed or reflected without our seeing it. Ultraviolet (UV) radiation is one type of invisible light, which travels at faster frequencies than light on the visible spectrum. UV radiation is broken down further into ranges of wavelengths:
- UV-A rays
- Used in tanning beds
- Were thought to be safe, but recent research is showing long-term damage potential (including skin cancer risk)
- Can penetrate glass and clouds
- UV-B rays
- Longest-known skin cancer risk factor
- Cannot penetrate glass
- UV-C rays
- Entirely absorbed by the earth's ozone layer
UV-A and B radiation penetrates the ozone layer and our skin, and that's where the potential for sun damage arises.
What does UV Radiation Do to Your Skin?
UV radiation penetrates the epidermis layer of your skin and is absorbed by various dermis-layer components, like collagen, elastin, melanin, etc. Absorbing UV radiation essentially energizes the compounds, which isn't all bad. UV radiation stimulates melanocytes' production of melanin, which can give your skin a healthy sun-kissed tan. At the same time, these cells are able to produce Vitamin D, an essential vitamin involved in several body processes. However, overstimulation of the melanocytes can result in hyperpigmentation or sun spots. Absorbed UV radiation energy is often a catalyst for other chemical reactions that may break down the molecular structure of the compounds in the skin matrix. Part of this chemical breakdown often involves the creation of free radicals: oxygen molecules that are missing an electron.
Free radicals are unstable and seek out a compound with a free electron or at least a compound with a weak enough molecular bond it can break to make an electron available which may be a bond in healthy tissues or skin components. Free radical damage is the major culprit in the breakdown of collagen and elastin. When these skin matrix components degrade, your skin loses its firmness and elasticity, resulting in sagging, wrinkled and dehydrated skin.
What is Overexposure?
Overexposure to the sun is known to cause sun damage and increase your risk for skin cancer. But just how much sun exposure is overexposure is impossible to know. The best protection is to wear sun protection whenever you're exposed:
- Wear sunscreen daily (you may already! Many daily moisturizers and makeup formulas have an SPF)
- Reapply sunscreen as need (it's always needed after you get wet, even if it says it's waterproof)
- Wear protective clothing
- Wear UV-filtering sunglasses
For more sun protection tips, visit the Skin Cancer Foundation's Prevention section: http://www.skincancer.org/prevention/sun-protection."
