Sunscreen cream has a chemical compound that protects the skin from the harmful effects of the sun’s ultraviolet rays (UV). There are two types of ultraviolet radiation: UVA (long-wave) and UVB (short-wave).
What is UV radiation?
UV radiation is part of the electromagnetic (light) spectrum that reaches the earth from the sun. It has wavelengths shorter than visible light, making it invisible to the naked eye.
Scientists classify the wavelengths as UVA, UVB, or UVC, with UVA the longest of the three at 320-400 nanometers (nm, or billionths of a meter).
UVA has two wave ranges, UVA I, which measures 340-400 nanometers (nm, or billionths of a meter), and UVA II which extends from 320-340 nanometers.
UVB ranges from 290 to 320 nm. With even shorter rays, most UVC is absorbed by the ozone layer and does not reach the earth.
Both UVA and UVB, however, penetrate the atmosphere. UVB radiation is harmful for the skin: it causes burns and increases the risk of skin cancer. In turn, UVA radiation acts less noticeably: there are no burns and redness from it, but it causes an appearance of freckles, pigment spots and other signs of aging skin.
The difference between 93, 97 and 99 percent may seem insignificant, but if the skin is too sensitive to sunlight or has a predisposition to skin cancer, an additional few percents of protection will play a decisive role.
In addition, it is the fact that none of the creams can provide 100%protection from UV radiation.
It is also important to mention some other facts and myths about SPF sunscreen creams. First, a cream of any level of protection is fully effective only for the first two hours, after which the degree of protection falls. Thus, it is recommended to renew the layer of cream on the skin approximately every two hours. Secondly, skin reddening is a reaction to UVB rays, but UVA rays effect may be hard to notice at the beginning. Even the most harmful effects of UVA rays rarely lead to an instant reddening of the skin and became noticeable only after a while.
Who needs to use SPF sunscreen creams?
Experts in dermatology advise all people in all age groups and even children older than 6 months to use sunscreen daily. Children under 6 months must be kept away from direct sunlight all the time.
Even office workers, who stay indoors most of their day, receive increased ultraviolet radiation during rare periods of going outside. In addition, UVA rays can pass through most of the office buildings.
What type of sunscreen should I choose?
The answer to this question depends on how much radiation you receive daily. In any case, it is recommended to use creams that provide protection simultaneously against UVA and UVB.
If you work or relax outdoors, you must use more serious means of protection, preferably water-repellent ones. Creams labelled “water resistant” and “very water resistant” are recommended not only for people who go to the beach, but also to all people who spend time outside or during sports, when the skin is sweating particularly intensely.
However, water resistant SPF creams may be not perfectly suitable for everyday life. They usually have sticky and soiling base, and make it harder to apply makeup.
Most high-quality modern moisturizing day creams or aftershave creams already contain SPF 15 or more. This is enough for daily use if you spend most of the day indoors.
Look for the following ingredients on the labels:
PABA derivatives (p-aminobenzoic acid derivative), salicylates (salicylic acid) and cinnamates (cinnamic acid) (octylmethoxycinnamate or cinoxate) – prevent UVB radiation;
benzophenones (benzophenone) (oxybenzone or sulisobenzone) – stop some UVA rays;
ecamsule (mexoryl), titanium dioxide (titanium dioxide) and zinc oxide (zinc oxide) – block the full spectrum of UVA rays.
Sunscreen cream application rules
Sunscreen should be first applied to the skin about half an hour before going out, so that the ingredients are absorbed.
Repeated application of the cream (approximately once every two hours) is equally important, that is, you need to apply the cream in the same amount. Re-use of sunscreen is also recommended immediately after bathing and wiping with a towel, as well as after excessive perspiration.
The most common myths about sunscreen:
Myth 1: “The use of sunscreen provokes vitamin D deficiency.”
This point of view is still controversial in scientific world, and experts are far from one hundred percent approval or denial of this fact.
In any case, if you think that your body lacks vitamin D, you can get it by consuming foods such as salmon, eggs, fortified milk and orange juice.
Myth 2: “You don’t need sunscreen in cool or cloudy weather.”
This is not true. Even when the sky is completely overcast, the Earth’s surface reaches about 40% of the solar radiation. Failure to understand this fact often leads to severe burns that have been received on cloudy days.