To sunbathe or not

Sunbathing improves mood and promotes calcium assimilation, but taking it too much causes burns, photoaging, photosensitization and even cancer.

Solar radiation

The surface of the Earth, and the humans who find ourselves on it, receive part of the radiation emitted by the Sun, while another important part does not penetrate the atmosphere that surrounds the Earth. In addition to the radiations that correspond to the visible spectrum, that of colors, we are affected by Ultraviolet (UV) and Infrared (IR) radiation.

Among the UV we have the UVB, which cause the erythema or sun tan, which penetrate our skin only to the epidermis, and UVA, which cause direct tanning by activating the pigment melanin and penetrate to our dermis. Finally, infrared IR radiation reaches us, which does not tan our skin, but it does heat it up to the deepest layer, which is the hypodermis.

Along with the aesthetic benefit on the skin, already mentioned, the sun's radiation gives us heat, puts us in a good mood and contributes to our bones assimilate calcium by promoting the synthesis of vitamin D, essential for bone health.

However, the same radiation, if we do not regulate the time and the way we are exposed to them, can cause harmful effects: from sunburn, to photosensitization, photoaging and. The injuries will depend on the more or less deep layer of the skin that is affected and the number of times the aggression is repeated.

The congenital protection factor: phototypes

In human skin there is a dermal pigment melanin that is activated by the sun, rises to the surface of the skin, causes the appearance of a "tan" and acts as a "shell" that prevents subsequent radiation from penetrating the interior.

Now, we do not all have the same amount of melanin and at first glance we can distinguish very white skin, with very little melanin in individuals with light and impossible eyes, and also, dark skin in individuals with black eyes that are always tanned.

These typologies are called Phototypes and experts distinguish 6 types (rising from 1 to 6) that indicate the degree of natural protection of a person against.

What to do when one has a low Phototype?

In the nineteenth and early twentieth centuries, the solution was to protect yourself from the sun by covering yourself with clothes, hats and umbrellas. Fortunately, since the 1940s, cosmetic science offers us the possibility of complementing or supplementing our melanin with substances capable of absorbing or repelling UV radiation with so-called “sun filters” that are incorporated into cosmetic formulations in a greater or lesser proportion depending on the Skin phototype to which they are indicated. They are distinguished:

• Chemical filters: which act by absorbing ultraviolet solar radiation, their percentage varies in the formulas according to the skin to whom they are intended.
• Physical filters: which act by reflection of light and are used alone or as a complement to the previous ones when greater protection is required
• biological filters: antioxidant substances that prevent the formation of free radicals and recover the skin defenses that the sun destroys.

What is SPF or SPF?

The Photoprotectors that we find today on the market incorporate a number that corresponds to their Sun Protection Factor or Sun Protection Factor. This number indicates the level of protection against UVB, that is, the more a photoprotective product increases the natural defense capacity of a skin. If a person begins to burn after 20 minutes in the sun, with a product of, for example SPF 20, it would take 20 x 20 to reach the same level of burn.

The SPF assessment methods are regulated by international organizations (FDA and COLIPA) with different protocols that, however, have something in common: they apply a continuous layer of product to the skin and in sufficient quantity to cover the skin to be protected.

They are recommended as a minimum of SPF 15 even for 5 or 6, while the European Union recommends that the maximum SPF be 50+ and advises avoiding nomenclatures: “extrem”; "Full screen" ... which only leads to confusion.

But a good sunscreen, nowadays, must also avoid the effects of UVA. There are no indexes similar to SPF referring to filtering UVA radiation, however international legislation determines that for a product to proclaim that it protects against UVA, the amount of this filter must be at least 1/3 of the UVA filter.

Finally, some firms are incorporating substances that counteract the action of IR (infrared) rays. The evolution of these products will have to be followed.

By way of conclusion, it is important not to forget that topical sunscreens have an important mission, to prevent the acute and chronic adverse effects of excessive sun exposure:

• Prevent solar erythema, in the acute phase.
• Delay photoaging.
• Reduce the risk of developing carcinomas and possibly also melanomas.

Cosmetic considerations

In addition to the value of the SPF against UVB and the presence in the formula of filter products of the UVA and correctors of the IR there are some more considerations when selecting a product for the sun. These are cosmetic considerations of the type of formulation in the form of: more or less greasy emulsion, greasy gel or non-greasy gel, spray oil ...

The most suitable product will be chosen according to the lifestyle and according to the area of ​​the body to be protected. A non-greasy gel will be suitable for a surfer that does not make him slip, whereas a seven-year-old child who spends the day at the beach between the shore and the water will have to apply a water-proof emulsion with a high percentage of fat.

For the face of a woman over 40 years old, for example, a highly moisturizing cream will be chosen and for her body an oil spray ...

In any case, it is important to insist that a Sunscreen product should be applied before leaving home, if possible calmly and in a generous layer all over the body. Once in the sun it will be necessary to reapply it if one bathes or sweats a lot. Otherwise, the SPF concept explained above is not applicable, since the theory of photoprotection does not work if it is not put into practice.

Let's take care of our skin every day, especially in the sun. We have only one skin that has to accompany us throughout our lives, so… let's try to make it look as good as possible!

• Benefits: the sun tans, gives heat, improves mood and favors the assimilation of calcium.
• Dangers: taken in excess it causes burns, photoaging, photosensitization and even cancer.
• The solution: use a suitable sunscreen for our skin type.

Mercè Camps Miro

Pharmacist, specialist in Dermopharmacy