Sunlight is energy in the form of electromagnetic radiation, most of which is filtered by the earth’s atmosphere.Only infrared rays (responsible for heat), ultraviolet type A and B, and visible spectrum radiation responsible for the colours we perceive reach our skin.
A part of these rays is reflected by the stratum corneum, the rest is absorbed bringing about positive effects (production of vitamin D, mood enhancement) but also negative ones such as pathological changes of the skin and photoageing.
The energy transmitted by UV rays causes the formation of free radicals that react in turn with the molecules of the cellular structures.
Followingacute sun exposure (intense but limited in time) like that we subject ourselves to during the summer, sun erythema appears.The skin becomes inflamed and reddened due to the excessive production of free radicals, and this leads to an increase in the production of melanin which presents itself as a tan.The latter, as aesthetically pleasing and pleasant it may be, is actually a reaction of our skin’s defences.
Ultraviolet A and B rays are harmful not only in the short term but also in the long term. Daily sun exposure, even if not intense, still results in cumulative damage. UVs progressively alter the dermis and epidermis producing the signs of photoageing and the appearance of skin tumours.
Premature ageing, with an appearance of thickened and translucent skin, roughness, blemishes and dilated capillaries, causes the skin to lose its beauty and balance. We must and can avoid it or, at least, slow it down.
Using cosmetics with a sun protection factor (spf) can help us:
- it makes the skin less vulnerable,
- it limits damage,
- it reduces inflammation and skin reactivity,
- it gives our skin time to recover and regenerate antioxidant reserves.
The sun protection factor (SPF)indicates the ability of a cosmetic to delay the onset of sun erythema and is calculated based on this formula:
SPF (Sun Protection Factor) = MED (minimal erythemal dose) with the use of sun protection / MED (minimal erythemal dose) without the use of sun protection
In simple and practical terms:
SPF (Sun Protection Factor) = time of onset of erythema with the use of sun protection / time of onset of erythema without the use of sun protection.
Conversely, if you want to know how long you can expose yourself to the sun after applying a photoprotector with SPF = n before solar erythema appears, simply invert the formula:
time of onset of erythema with the use of sun protection = SPF x time of onset of erythema without the use of sun protection.
Let’s assume that your skin normally turns red after just 10 minutes of sun exposure. If you apply a cream with SPF= 30, the onset of erythema will not occur after 10′ but after 300′ (30 x 10′), i.e 5 hours.
Is that actually true?
Be careful, only in theory, because the protection factor is a rather approximate (laboratory) index as it does not take into account “live” and individual factors including phototype, skin type, skin condition itself at a given moment, season, climate and latitude.
A basic rule to take care of your skin is to knowit, to know what kind of skin we have and our phototype (basic pigmentation and pigmentation capacity).Only in this way can we apply any of the other rules I have suggested to always have perfect skin: respect the skin.
This implies choosing and using cosmetics that are suitable for your skin, but also healthy and moderate sun exposure.
We must not deprive ourselves of the pleasure of soaking up the sun, but we must protect our skin from excessive exposure and damage, even from that, little but constant, due to our inevitable exposure to sunlight every day.
Cosmetics can include substances that interact chemically with the sun’s rays, absorbing their energy (chemical filters) such as cinnamates, triazine and mexoryl, or those that physical reflect light (physical filters).
It is important to apply a little but constant sun protection, through the daily use (all year round) of cosmetic products containing preferably physical sunscreens (micronised titanium dioxide and zinc oxide): these reflect not only the UV but also infrared rays, equally harmful for fair and couperose skin.
If these products also contain ingredients with antioxidant properties such as olive oil, chlorella alga (rich in chlorophyll), vitamin E or tocopherol, vitamin C and phytosterols, then they will be even more effective for the beauty of the skin.They will have a defence action, not only passive, but also active because they will help neutralise free radicals from the very beginning.
Finally, we can say that regular application of sun protection, as part of our daily cosmetic routine, may very well be the best anti-wrinkle advice we can follow!
Autohr: Dott. Francesco Antonaccio
Website: https://www.dermatologoparma.com/
