Benefits and harms of sun radiation for humans have long been the subject of attention of scientists around the world.It is known that ultraviolet rays are different wavelength and are divided into 3 types: UVC - short, UVB - medium length, UVA - the longest.UVC-rays are not dangerous for humans, becausedue to the short length of its waves do not reach the Earth's surface is completely absorbed by the ozone layer of the atmosphere.Two other types are distinguished by the degree and nature of the effect on human skin.In addition to use solar rays cause the skin to produce vitamin D, contributing to strengthening bone tissues in the body, there is a risk of burns, premature skin aging and the development of melanoma (malignant tumors).
To reduce the harmful effects of ultraviolet radiation using a sunscreen with SPF-PPD- and indexes that serve as filters, delay rays, preventing them from getting to the skin.Filters SPF protects against UV rays in the range of filters PPD - from the rays of the spectrum
to a sunscreen with SPF-PPD- and factors provide the most effective protection, it is recommended to put them in the same way as regular, 20-30 minutes before going outside.During this time means absorbed into the skin, and it will be ready for sunbathing.
sunscreen with SPF the PPD and applied to the skin more dense layer than the usual daily caring means.For persons optimal portion is equal to the amount of cream, which is placed on the ball of the finger, and the body, it is about two to three tablespoons.
should be remembered that even the most resistant sunscreens lose their properties after a certain period of time and as a result of mechanical action.It is therefore necessary to update the cream on the skin at all times during your stay in the sun - about two hours and after each swim in the pond.