The dangers of over-exposure to sunlight are well-known to produce cancers and hasten aging. Exposed skin ages quicker than protected skin. The signs of aging appear first on the face followed by other exposed areas, such as the hands. Skin abnormalities such as dyschromias, solar lentigines and seborrheic keratoses are all signs of UV exposure. Sun protection products either physically block the sun’s rays or absorb specific levels of solar radiation (chemical screening).
It is essential to understandthe leading cause of "premature aging" is skin damage caused by UV ray exposure. Here is an explanation of sun care terms that will enable you to make an informed decision regarding your sun protection.
Broad Spectrum: The sun's rays contain different wavelengths of ultraviolet (UV) light. The two types of UV rays that pass through the earth's atmosphere and cause damage to the skin are UVB and UVA. UVB rays are the primary cause of sunburn and affect the outer layer of skin.
The strength of UVB radiation depends upon the time of day, season of the year, and geographic location. UVB rays are most intense from 10.00 am to 2.00pm and are stronger in summer, at higher altitudes, and closer to the equator. Particularly in New Zealand where the protective ozone layer surrounding the earth has depleted, there is a significant increase in the strength of UV rays.The UVB rays have a shorter wavelength meaning that they do not penetrate into the deep layers of the skin.
In contrast, UVA rays have a longer wavelength thus penetrating deeper into the skin and producing the aging associated with chronic sun exposure. This "aging" includes sagging skin and loss of elasticity, pigment changes, deep wrinkles and dry skin. Recent studies have shown a strong link between UVA rays and the development of melanoma. Broad spectrum generally refers to a product which will protect from both UVA and UVB rays.
SPF stands for sun protection factor. SPF measures how long it takes protected skin to begin to sunburn (turn red) as compared to unprotected skin. For instance if unprotected skin takes 10 minutes to burn, then skin protected with a SPF value of 15 will take 150 minutes to burn, (this period of protection can be reduced by exposure to water or moderate to heavy perspiration). SPF values only rate the level of UVB protection.
It is a common mistake to assume that the duration of effectiveness of a sun protection product can be calculated simply by multiplying the SPF by the length of time it takes for a client to suffer a burn without protection because the amount of sun exposure a person receives is dependent upon more than just the length of time spent in the sun. The amount of sun exposure depends upon many factors including the length of exposure, time of day, geographic location, and weather conditions.
Higher SPF levels are achieved with a significant increase in the levels of active ingredients, which some individuals find to be irritating to the skin. It is best to use a moisturizing SPF 15 formulation every day, with the use of a SPF30 for times of intended sun exposure and to reduce irritation many people find it preferable to use a 'natural' physical block versus a chemical screen.
Higher SPF values potentially give consumers a false sense of security, encouraging them to stay out longer in the sun and not reapply sunscreen as often as necessary. The alarming rise in skin cancer with the development of advanced sun care products has shown this. Reapplication is more important than SPF values and one should reapply regularly, especially once exposed to water or perspiration.
Physical vs. Chemical blocks: Sun protection products can be broadly classified into two categories; chemical screens and physical blocks. Chemical sunscreens absorb UV radiation, while physical blocks act by physically blocking UV radiation. Some chemical sunscreens can contain ingredients that cause reaction in sensitive skins, so it is important to trial your sun protection product. The nature of chemical protection is that wave lengths are absorbed and converted to heat which can also cause irritation. Physical blocks are patted on to the skin to reflect UV rays rather than absorb.
Remember: Sun blocks do wear off, rub off and are perspired off so do need to be reapplied. The SPF rating (for example 15) is applicable from the time of application, not from the time you walk out into the sun.
Dermablock 15+ is a physical and chemical sun protection cream. Dermablock Zn 30+ is a purely physical block.