Do you know what the SPF or sun protection factor is?
The distance between the sun and the earth is 150 billion kilometers and even so the force of the rays that reach our planet is very high. Among the emissions that come from the sun, are:
• infrared radiation (50% reaches the earth and is mainly responsible for heat),
• visible light (provides light energy and gives us vision)
• and ultraviolet radiation, including UVA, UVB and UVC rays, the latter are completely filtered by the ozone layer and do not reach the earth.
• UVA. Penetrates deep into the dermis, damages collagen, decreases elastin production and causes premature photoaging. They also stimulate the production of melanin, favoring hyperpigmentation and the appearance of spots on the skin. They contribute to skin cancer by 35%.
• UVB. Radiation more energetic than UVA. It affects the epidermis, causing sunburn and DNA damage. They contribute to photoaging and skin cancer by 65%.
• UVC. It is retained by the ozone layer.
The solar protection factor (SPF), indicates how long a sun protection cream is capable of increasing the natural ability of the skin to protect against redness prior to a burn.
For example, a light-skinned person who normally begins to burn after 10 minutes in the sun, with an SPF 15 cream would take 15 times longer, that is, 10 x 15 = 150 minutes (2 hours and 30 minutes).
The SPF is measured under controlled conditions in the laboratory and the characteristics and hydration of each skin, the amount of cream used and the environmental conditions during exposure are not the same as those found in a laboratory environment, therefore, they are approximate values. For correct and lasting protection we must reapply cream during exposure as the skin demands it.
We need the sun to live and for life to exist, in addition to providing heat, it is the main source of vitamin D, which helps to fix the calcium absorbed by the body, necessary for the proper maintenance of strong and healthy bones.
As a recommendation, excesses are not usually good, that is why exposure to the sun must be in the right measure and always with the appropriate protection cream.