Earlier, we had discussed the importance of having enough Vitamin D in our body as it is important for healthy skin. As was mentioned, sun exposure raises our vitamin D levels and enhances our mood. However, sun exposure also damages our skin, causing wrinkles, hyper-pigmentation (sun spot or age spot), and sometimes cancer.
The best method to protect your skin is with physical protection (long sleeves, hats, etc.) and with sunscreen which helps protect the skin against the damaging effects of sunlight. But with hundreds of sunscreen products on the market, how do you go about choosing the best one? Before we can answer that question, we need to discuss and explain the light properties from the sun. UV (Ultraviolet) rays have wavelengths shorter than visible light, and therefore can’t be seen by the human eye. These UV rays are categorized into 3 types: UVA, UVB, and UVC.
UVC rays emitted from the sun are absorbed by the ozone layer and do not reach the earth. UVA rays (320-400nm) have longer rays compared to UVB rays (290-320nm).
UVA rays account for about 95% of the rays that reach the earth. UVA rays penetrate deeper into the skin and are suspected of contributing or even initiating skin cancers. Because UVA rays penetrate deeper into the skin, there is no burning or redness associated with UVA radiation. Tanning booths emit UVA radiation. The sunlamps used in tanning salons can emit 12 times more UVA radiation compared to the sun, therefore increasing the chances of skin damage. That is why it is important to stay away from tanning salons.
UVB rays are shorter and stop at the surface of the skin and cause redness and burning. UVB rays are known for damaging the epidermis and play an important role in skin aging and development of skin cancer. Having discussed UVA and UVB, let’s now talk about 4 important things to consider when choosing a sunscreen: SPF, UVA and UVB protection, and the ingredients in the sunscreen.
SPF stands for Sun Protection Factor and it is the standard used to rate sunscreens since the 1970's. It refers to the amount of UVB radiation that causes redness while wearing the sunscreen in comparison to the amount it would take without it. Although this is important, SPF rating has its limitation: it does not indicate UVA protection. In addition to the exposure time, other factors such as skin type, the amount of sunscreen applied, the frequency of reapplying the sunscreen, and the type of outdoor activity also make a big difference in preventing sun-induced skin damage.
So what SPF rating is sufficient? An SPF 30 blocks close to 97% of the sun's rays and is usually sufficient. With higher SPF products, you often end up paying twice or three times the price. But those products do not provide any significant amount of increased protection. In fact the chemicals used in the higher SPF products are much more likely to irritate the skin.
The best advice: Use SPF 30 and re-apply the sunscreen often if you will be out in the sun for more than 30 minutes. In addition to UVB protection, be sure that the sunscreen protects against UVA rays. Remember 95% of the rays reaching the earth are UVA rays!