In the summer, from behind the Sun, our skin is exposed to an extremely intensive effect, which not only can lead to burns, but also to be the cause of various diseases. These effects are characteristic of everyday life in the city, which is, to talk about a beach holiday. Therefore, it is not necessary to neglect the use of sunscreen, the choice of which is extremely diverse on the market. But it combines their one - the presence of an abbreviation SPF on the package. Unfortunately, on the Internet a lot of controversial information about SPF. Let's figure out where the truth is, and where the fiction.
What is measured by SPF
SPF or Sun Protection Factor is a conditional characteristic that helps our skin to protect against ultraviolet. Sunsters have SPF from 6 to 50. In some cases, they write 50+, but it is not obvious, which understands the manufacturer under this number.
The digit standing after the letters SPF is usually explained as an increase in the duration of the sun without consequences for the skin in the specified number of times. That is, if your skin in the sun blues in 10 minutes (depending on the type of skin, this value can be from 5 to 30 minutes), then the tool with SPF 20, it seems like, prolongs the protective properties by 10 × 20 = 200 minutes. This explanation has a significant drawback: it turns out that SPF 6 and SPF 50 protect the skin equally, only in the first case the effect lasts 60 minutes, and in the second - 500. In fact, the SPF value characterizes the percentage of UV rays, the protection of which provides a means. SPF 15 will protect from 93.3%, SPF 30 - from 96.7%, and SPF 50 is from 98%. It does not have to talk about greater protection if it takes place, then only in the form of a percentage. Previously, cunning marketers, carried away, wrote on the packages the value of SPF 100 and 150. Today it is prohibited, because it does not make any sense and disinforms the consumer.
If we talk about the level of protection less than 15, then, in fact, the use of such funds is not enough. Strictly speaking, they skip enough ultraviolet to apply skin damage. For example, with SPF 6 to the skin, 16.7% of the rays will get, which, of course, cannot be considered a safe dose.
How long is the defense
The SPF value you need to be determined directly, based on the type of skin, but not from the time it is supposed to spend in the sun. If we talk about the duration of the effect, it depends on the type of filters, as well as on the nature of the impact.
Filters are chemical (for example, autobenzon, benzophenone) and physical (zinc oxide or titanium dioxide). They differ on the principle of work. At the same time, chemical filters will be effective when used in everyday life - on the beach they can bring more harm than good. Two hours later, the structure of them begin to change them in the sun, and it is possible to protect them only carefully removing and resumeing the tool.
Physical filters are less sootheliva, on the beach it is worth using them. But they gradually lose their usefulness, as they wash off or erased as a result of mechanical impacts. So they should also be updated every 3-5 hours, as well as every time after bathing. Waterproof sunscreens that attract customers some manufacturers are designed to protect the skin directly during swimming (yes, water also misses ultraviolet). However, after returning to the shore, such protection should also be renewed.
On the spectra of UV radiation
It is impossible not to mention the spectra of ultraviolet rays. The rays of the spectrum in (UVB) are distinguished, which cause burns, and the rays of the spectrum, A (UVA) responsible for the aging of the skin. From the first prevents most sunscreens. To protect against spectrum rays, and there are means with a mark of UVA on the package. The sake of fairness should be said that the mechanism of exposure to these rays on the skin is not fully studied, and some experts doubt the effectiveness of such protection.
You can say for sure that it is worth using conventional advice to minimize photorement - to reduce the time of staying in the sun, do not go outside during the greatest solar activity - from 12 to 15 hours. Do not forget that ordinary clothes also misses a significant amount of spectrum rays A, that is, protects against burns, but does not save from aging, appearance of wrinkles and pigmentation.
Does decorative cosmetics protect?
As for decorative cosmetics with SPF, the protective properties of it is not very high, and with intense sun, it is better to still apply special sunscreens. However, often enough cosmetics. For example, the decorative powder is well absorbed ultraviolet, providing SPF 15-20 protection. At the same time, it does not score skin pores, which is also very important in the summer.
It is not necessary to pay attention to the high cost of the funds and fame of the brand. From cosmetics promising SPF 30 or 50, or other unprecedented "anti-Age" properties, you should not expect something special. All this is nothing more than words. On the beach still use ordinary, but proven special means that will ensure reliable protection.