Why protect yourself from the sun?
Sun protection: Tips for staying safe in the sun
Protecting yourself from the sun is essential for your health. How to choose the right sun protection among sun indices, chemical filters and mineral filters?
Why protect yourself from the sun?
Solar radiation is implicated in many diseases. Limiting overexposure to the sun would prevent 4 out of 5 skin cancers.
The sun's rays
In the light spectrum, UV (ultraviolet) rays are located beyond the violet color, and are invisible. There are 3 types:
- UVA : 95% of UV rays reach the earth's surface. They penetrate the skin to the dermis and cause immediate pigmentation that does not last . UVA rays are responsible for long-term effects: skin aging and skin cancers. They pass through glass (windows, etc.)
- UVB : 5% of UV rays reaching the surface of the planet. They penetrate into the epidermis. They are responsible for sunburn, thickening of the skin, tanning. They are blocked by glass (windows, etc. )
- UVC : the most harmful are mainly absorbed by the ozone layer and do not reach the earth's surface.
Tanning, a natural protection?
The skin has two main ways of protecting itself from the sun :
- Thickening of the horny layer: hyperkeratosis
- Melanin pigmentation: tanning
Tanning offers some protection against UVB rays (maximum protection factor SP6) but not against UVA rays.
Self-tanners and tanning accelerators do not provide UV protection .
Food supplements that can give a tanned complexion and prevent lucites (sun allergies) do not protect against the sun's rays either .
Sun capital: capital not to be risked!
The sun capital is specific to each person, it includes all the skin's means of defense against solar aggression. It depends on:
- On the intensity and duration of sun exposure throughout life: exposures before the age of 20 are more risky. Children under 2 years old should not be exposed directly to the sun!!
- Phototype : This is the sensitivity of the skin to the sun: the lighter it is , the more sensitive it is. There are 4 phototypes, from type 1 for very light skin to type 4 for black skin.
To learn more about the proper use of sun protection, click here .
How to prevent solar risk?
The UV index provides information on the most suitable sun protection . It is necessary to protect yourself as soon as the UV index is higher than 3.
Solar eviction
The amount of UVA received by the skin is constant throughout the day, the amount of UVB received depends on different factors:
- The times : in summer, between 12 p.m. and 4 p.m. the sun is at its zenith, UVB rays pass through the atmosphere more easily and are therefore less filtered by it.
- Clouds : A thick cloud filters more of the sun's rays. A cloudy sky lets 95% of the radiation through , although the impression of heat is reduced.
- The altitude
- Reverberation : Water and white surfaces reflect nearly 85% of the sun's rays, increasing the amount of UV rays received by the skin. Under a parasol, 50% of UV rays can pass through and sand reflects 15 to 20% of the sun's rays .
Wearing covering clothing
- Dark clothing protects better from the sun, even if it absorbs infrared rays and the sensation of heat is greater. Damp or wet clothing blocks UV rays less well (perspiration)
- Category 3 (high brightness) or 4 (exceptional solar brightness) sunglasses are essential to protect your eyes. Category 4 is recommended for babies and young children.
Using sun protection
A sunscreen product must protect against UVA and UVB:
- UVB protection is defined by a sun protection factor (SPF)
- Minimum UVA protection is at least one-third of the SPF, and should cover the highest UVA wavelengths
The sunscreen product with SPF and UVA labeling guarantees these criteria.
The choice of protection indices for a sun cream is made according to the phototype. There are 4 categories of sun protection:
- Low protection: SPF 6 or 10
- Medium protection: SPF 15, 20 or 25
- High protection: SPF 30 or 50
- Very high protection: SPF 50+
Taking photosensitizing medication requires increased sun protection ; consult your pharmacist or doctor to check your treatment.
Sunscreen should be applied before exposure to all exposed surfaces, including hands, ears, temples and feet . For an adult of average build, approximately 36 g (6 teaspoons) is recommended.
Sun protection should be renewed every 2 hours and/or after swimming, toweling or if sweating.
Exposure time should not be prolonged regardless of the protection index used.
Sun protection products: chemical filters and mineral filters
Sun creams and milks are cosmetic preparations containing chemical and mineral filters that protect the skin from the sun's rays.
Chemical filters
These are molecules that absorb UV rays. Their effectiveness depends on their absorption zone:
- Narrow spectrum filters absorb in the UVB
- Broad spectrum filters absorb in the UVB and up to the UVA
These filters can cause skin reactions (irritation, contact allergy), accentuated by the recommended renewal of applications. The most incriminated chemical filters are:
- Benzophenone (or oxybenzone)*
- 4-Methylbenzylidenecamphor (4-MBC)*, and 3-BC (3-benzylidenecamphor)*
- Para-aminobenzoic acid (PABA) derivatives
- Octocrylene
*classified as endocrine disruptors
These chemical filters should not be used on damaged or injured skin, or on infants.
A toxic effect (endocrine disruptor*) has been observed on the marine ecosystem (fish and corals). There are sunscreens formulated specifically to preserve the environment.
Mineral filters
Mineral filters reflect and scatter UV rays. They are photostable, non-allergenic and non-toxic. Two mineral filters are used:
- Titanium dioxide
- Zinc oxide
Mineral filters leave a white effect on the skin and are not very fluid, which makes their application less easy.
These mineral filters are often formulated in nanoparticles. These are particles whose size varies from 1 to 100 nanometers (a strand of DNA measures 2 nm). In this form, sunscreens are easier to apply and do not leave white marks.
It is recommended not to use cosmetic products containing nanoparticles on damaged skin or following a sunburn.
Since 2013, manufacturers must indicate the presence of nanoparticles in the list of cosmetic ingredients, for example: titanium oxide [nano]
Mineral screens are preferred for babies, kids, pregnant women and reactive skin, avoiding nanoparticles. Prefer eco-labeled mineral protections without nanoparticles.