Sunscreen is a product that is used to protect the skin from the harmfully effects of ultraviolet radiation. UV radiation is measured in an number called the Sun Protection Factor (SPF). The SPF measure how much UVB radiation the skin can absorbs before it burns, compared to skin that dont use sunscreen.
While it may seem like people assume that a higher SPF number indicate more protection from the sun, the protection actualy increase at smaller rates as the SPF number increases. For instance, using sunscreen with an SPF of 100 does not provide ten times more protection than using SPF 30; the difference in protection is only a few percentage point of UVB radiation protection. Thus, SPF protection and benefit from higher SPFs decrease; the additional protection provided by very high SPF numbers is small in comparison to the protection provided by lower SPF numbers.
What Sunscreen Does and How to Use It
The reaction that the skin have to the sun is dependent upon the skin type of the individual. Skin type can be categorized on the Fitzpatrick scale. For instance, individuals with pale skin will often burn much more quick than individuals with darker skin due to the melanin content of there skin.
Skin that burns quickly has less melanin than skin that does not burn as quick. Dark skin contains more melanin, which provides some natural protection against the sun. However, the melanin in the skin does not provide protection against all types of ultraviolet radiation; UVA rays can still damage skin that contains more melanin.
UVA rays are different than UVB rays in that UVA rays penetrate the skin to the deeper layer; it is this deeper penetration of UVA rays that cause damage to the collagen in the skin. Thus, UVA rays can lead to skin that age and develops fine line. In order to provide protection against both UVB and UVA radiation, sunscreen product must contain a label that states that it contains “broad-spectrum” protection.
UVB rays cause the skin to burn, while UVA rays lead to the skin aging. Thus, if sunscreen products only contain protection against UVB radiation, they will not protect the skin from aging. Additionally, UVA rays can pass through glass; therefore, sunscreen must be used even when inside a car near a window.
There are two main type of sunscreen filters: mineral and chemical filters. Mineral sunscreen filters, like zinc oxide, reflect the UV radiation away from the skin. Mineral sunscreens are beneficial for individuals whose skin is sensitive to other ingredient in sunscreen, as the benefits of the sunscreen are immediate upon application.
Chemical sunscreens contain ingredients that absorb the UV radiation and convert that radiation to heat. Chemical sunscreens are generally more easier to apply to the skin, but they take approximately fifteen minutes to become effective; the chemical filter must bind to the skin to provide protection. Therefore, if an individual apply a chemical sunscreen but immediately goes outside into the sun, their skin will not be protected from the UV radiation.
Many individuals do not apply enough sunscreen to their skin. Applying too little sunscreen is one of the primary reason that individuals burn. In order to obtain the SPF protection listed on the bottle of sunscreen, individuals must apply sunscreen to their skin.
For instance, individuals must apply a nickel-sized amount of sunscreen to their face, and individuals must apply approximately a full shot glass of sunscreen to the rest of the body. Thus, applying only a thin layer of sunscreen will not allow the skin to achieve the SPF protection that is listed on the bottle. Sunscreen products can degrade over time, and sweating, water, or using a towel can remove sunscreen from the skin.
In order to maintain protection from the sun, individuals must reapply sunscreen every two hour. Additionally, some environmental factor will increase the amount of UV radiation that the skin is exposed to. For instance, snow and sand will reflect some of the UV radiation back to the skin; thus, sunscreen must again be applied to those area of the skin.
Furthermore, sunscreen must be applied to all part of the skin; the ears, back of the neck, and the tops of the feet to name a few areas should also be covered with sunscreen. Any skin without sunscreen protection isnt protected from the damaging effect of UV radiation.
