WHAT IS SUN PROTECTION FACTOR (SPF)?

Sun's rays have a positive influence on our skin's beauty and health. Being, along with that, the major cause for its early ageing.

Staying in the sun, our skin cannot feel the effect of ultra-violet radiation till it is developed in tan or sunburn. Tan is your skin's protective reaction on direct influence of the ultra-violet rays.

UVA and UVB rays have negative influence on our skin. UVA rays are especially dangerous: they penetrate deeply into the deep skin layers, destroying collagen and elastine fibres, aid in the loss of natural moisture and early ageing. Apart from that, the influence of UVA rays leads to the majority of allergic reaction.

UVB rays have more general effect: most of them are reflected by corneuos layer, while the rest of them stimulate skin's protective mechanisms, aiding in consolidation of epidermis (superficial skin layers) – thus protecting deeper skin layers. UVB rays stimulate the production of melatonine (providing skin with bronze shade), which allows to increase sun's doses without burning it. One just needs to know that this process demands a certain time which we, as a rule, do not want to spend.

Sun protection depends on skin type. Each skin type has a different reaction on sunbathing. Unprotected skin may be exposed to sun without any damage for several minutes only:

• very light-complexioned skin - 2 to 7 minutes;
• light-complexioned skin - 7 to 14 minutes;
• dark-complexioned skin - 14 to 20 minutes;
• very dark-complexioned skin - 20 to 30 minutes

This is a very primitive scale and all of us know how quickly our own skin gets red in the sun. Sunburn is a signal to the fact that skin's protective mechanisms cannot cope with the load. For the prevention of sunburns and early ageing skin needs protection. Which can be performed by the help of UV-filters, as well as special products, improving skin's protective potential.

Sun protection unit is sun protection factor – SPF, which shows how long our skin, protected with special products, may be exposed to direct sun's rays as opposed to unprotected skin. The higher SPF is, the better is protection. The lighter complexion is, the higher SPF should be used. For example, if you are very light-complexioned and you may stay in the sun for not more than 5 minutes without growing red, on using SPF 7, you may enjoy the following equation: 5 min x 8 = 40 minutes. Protection degree depends also on the amount of applied protective product.