What is UV Light?
Ultraviolet (UV) light is that part of the light spectrum that is not visible to the human eye and falls in the range of 200 to 400 nanometres. A certain and regular amount of exposure to UV light is healthy as it kills harmful bacteria.
But overexposure results in suntan or worse sunburn. The latter condition results from overexposure to UV light and is harmful. It causes the skin to dry, peel, wrinkle, age faster and blister. In extreme cases, it can even cause cancer.
People prone to prolonged exposure to sunlight, like farmers, road construction workers, delivery boys, trekkers, etc should use suntan for protection.
Different people use sunscreens for different reasons. Some use it to protect the sun from damaging their skin so that they can stay in the sun longer and acquire a fashionable suntan!
How Does Sunscreen Work?
Like we said earlier, UV light itself is not harmful. But overexposure in general means prolonged exposure to certain wavelengths in the UV light spectrum. This is what causes sunburn.
In scientific terms, overexposure to Ultraviolet A1 or UVA1 (300 to 400 nm) and UVC (up t 340nm). While UVA1 causes skin to tan, UVC causes it to burn and blister.
Sunscreens or sun block works to reflect, scatter and absorb the UV light and comes in the form of lotions, gels and sprays. It thus acts as a filter between sunlight and the skin.
The measure of a sunscreen is the SPF factor or the Sun Protection Factor. It is a ratio of the time a person using sunscreens can stay in the sun without getting sunburnt Vis a Vis the length of time they can stay in the sun without sunscreen and without getting burnt.
How Strong is Sunscreen?
Therefore if you use a sunscreen with an SPF of 10, it means if you can stay in the sun for 30 minutes without getting burnt, the sunscreen will allow you to stay in the sun for as long as 320 minutes without getting burnt.
Sunscreens can be used as frequently as required and should ideally be applied a short while before actually stepping out into the sun. This gives the skin enough time to absorb the application, especially of you plan to enter water as at the beach.
Sunscreens rarely cause allergic reactions but careful it does not irritate your eyes. This can happen if, for example, you apply it to your forehead and allow the perspiration to trickle down into your eyes.
Sunscreen and Cancer
Sunscreen is known to prevent some cancers like actinic keratosis. These are lesions with warts and manifest themselves on the face or hands. These lesions are known to develop into squamous cell carcinoma, a kind of cancer linked to prolonged exposure to the sun.
Research will; however, tell you that sunscreens have no effect on preventing basal cell carcinoma, or malignant melanoma.
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