Part 3 of 4
Sunscreens are products combining several ingredients that help prevent the sun’s ultraviolet (UV) radiation from reaching the skin. Two types of ultraviolet radiation, UVA and UVB, damage the skin. Ultraviolet A (UVA) is the longer wave UV ray that causes lasting skin damage and can cause skin cancer. UVA rays, which penetrate the skin more deeply, are associated with wrinkling, leathering, sagging, and other light-induced effects of aging (photoaging). Ultraviolet B (UVB) is the shorter wave UV ray that causes sunburns and skin damage.
Sunscreen products act like a very thin bulletproof vest, stopping the UV photons before they can reach the skin and inflict damage. There are two main types of active sunscreen ingredients: chemical and physical. Chemical ingredients work by absorbing UV and reducing its penetration into the skin, whereas physical ingredients stay on top of the skin and deflect UV rays. Sunscreens vary in their ability to protect against UVA and UVB. Many sunscreens available today combine chemical and physical ingredients.
SPF – or Sun Protection Factor – is a measure of a sunscreen’s ability to prevent UVB from damaging the skin. If it takes 20 minutes for your unprotected skin to start turning red, using an SPF 15 sunscreen theoretically prevents reddening 15 times longer – about five hours. Another way to look at it is in terms of percentages: SPF 15 filters out approximately 93 percent of all incoming UVB rays. SPF 30 keeps out 97 percent and SPF 50 keeps out 98 percent. Broad-spectrum sunscreens protect the skin from both UVA and UVB rays. But SPF numbers are determined in a lab. In the real world, no matter what the SPF, sunscreens start to lose effectiveness over time, so it’s important to reapply every two hours and after swimming or heavy sweating. Also note that above SPF 50 the amount of additional sun protection is negligible.
The terms “water-resistant” and “sweat-resistant” indicate whether the sunscreen remains effective for 40 minutes or 80 minutes when you are swimming or sweating. But no sunscreen is fully “waterproof” or “sweatproof.” Stronger, water-resistant, beachwear-type sunscreens hold together on your skin and are good for hot days or while playing sports, because they’re less likely to drip into your eyes when you sweat. However, these sunscreens may not be as good for everyday wear. They are stickier, don’t go as well with makeup, and need to be reapplied every two hours.You should apply sunscreen under makeup.Sunscreens are available as gels, creams and lotions.
Sunscreens should be applied 30 minutes before sun exposure to allow the ingredients to fully bind to the skin. Be sure to apply generously and evenly on all sun exposed areas of the skin including face, ears, neck and hands. Reapplication of sunscreen is just as important as putting it on in the first place; so reapply the same amount every two hours. Sunscreens should also be reapplied immediately after swimming, toweling off, or sweating a great deal. Also apply a lip balm that has a sunscreen to protect your lips from sunburn.
It’s a myth that if it’s cold or cloudy outside, you don’t need sunscreen. This is not true. Up to 80 percent of the sun’s UV rays reach the earth on a completely cloudy day. In addition sand reflects 25% of the sun’s rays and snow reflects 80%. This misconception often leads to the most serious sunburns, because people spend all day outdoors with no protection from the sun.
UV radiation allows the body to create vitamin D, and some have suggested that sunscreen use makes it difficult to obtain adequate amounts of vitamin D. The fact is that real life conditions prove clearly that sunscreen use does not cause vitamin D deficiencies. Getting an adequate amount of vitamin D is dependent on these three tactics: 1) eating foods that contain vitamin D, 2) taking a vitamin D supplement, and 3) getting a small amount of sun exposure. Please note that you do not need to tan or burn your skin to produce vitamin D. Adequate vitamin D can be obtained safely and cheaply through food and dietary supplements without the risks associated with overexposure to UV radiation
Though using sunscreen is a vital sun safety strategy we always recommend a complete sun protection regimen that includes not only sunscreen use, but also seeking shade, covering up with clothing including a wide-brimmed hat and UV-blocking sunglasses.