SPF Means .
SPF stands for Sun Protection Factor. It's a number that you can use to help determine how long you can stay in the sun before getting a sunburn.
Since sunburns are caused by UV-B radiation, SPF does not indicate protection from UV-A, which can cause cancer and premature aging of the skin.
Your skin has a natural SPF, partially determined by how much melanin you have, or how darkly pigmented your skin is. The SPF is a multiplication factor. If you can stay out in the sun 15 minutes before burning, using a sunscreen with an SPF of 10 would allow you to resist the burn for 10x longer or 150 minutes.
Although the SPF only applies to UV-B, the labels of most products indicate if they offer broad spectrum protection, which is some indication of whether or not they work against UV-A radiation. The particles in sunblock reflect both UV-A and UV-B.
The reflective particles in sunblocks usually consist of zinc oxide or titanium oxide. In the past, you could tell who was using a sunblock just by looking, because the sunblock whited out the skin. Not all modern sunblocks are visible because the oxide particles are smaller, though you can still find the traditional white zinc oxide.Sunscreens usually include sunblocks as part of their active ingredients.
The portion of the sunlight that is filtered or blocked is ultraviolet radiation . There are three regions of ultraviolet light.
- UV-A penetrates deeply into the skin and can lead to cancer and premature skin aging.
- UV-B is involved in tanning and burning of your skin.
- UV-C is completely absorbed by the earth's atmosphere.
UVA and UVB, damage the skin, age it prematurely, and increase your risk of skin cancer.
UVB is the chief culprit behind sunburn, while UVA rays, which penetrate the skin more deeply, are associated with wrinkling, leathering, sagging, and other light-induced effects of aging.
Sunscreens vary in their ability to protect against UVA and UVB.
- PABA (para-aminobenzoic acid) absorbs UVB
- Cinnamates absorb UVB
- Benzophenones absorb UVA
- Anthranilates absorb UVA and UVB
- Ecamsules absorb UVA
Anyone over the age of six months should use a sunscreen daily. Even those who work inside are exposed to ultraviolet radiation for brief periods throughout the day, especially if they work near windows, which generally filter out UVB but not UVA rays.
Children under the age of six months should not be exposed to the sun, since their skin is highly sensitive to the chemical ingredients in sunscreen as well as to the sun's rays. Shade and protective clothing are the best ways to protect infants from the sun.
What type suncreen to use?
The answer depends on how much sun exposure you're anticipating. In all cases we recommend a broad-spectrum sunscreen offering protection against both UVA and UVB rays.
Many after-shave lotions and moisturizers have a sunscreen (usually SPF 15 or greater) already in them, and this is sufficient for everyday activities with a few minutes here and there in the sun. However, if you work outside or spend a lot of time outdoors, you need stronger, water-resistant, beachwear-type sunscreen that holds together on your skin.
Common Myths :-:
Wearing sunscreen can cause vitamin D deficiency!
There is some controversy regarding this issue, but few dermatologists believe (and no studies have shown) that sunscreens cause vitamin D deficiency. Also, vitamin D is available in dietary supplements and foods such as salmon and eggs, as well as enriched milk and orange juice.
If it's cold or cloudy outside, you don't need sunscreen.
This is not true. Up to 40 percent of the sun's ultraviolet radiation reaches the earth on a completely cloudy day. This misperception often leads to the most serious sunburns, because people spend all day outdoors with no protection from the sun.
Hope this article will you an idea of spf and usage of suncreens ,feel free to write your views @
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