UVB(ultraviolet B), UVA (ultraviolet A) and visible light make up a small, yet significant portion of the electromagnetic spectrum of light entering the earths atmosphere.
UVB causes us to burn while UVA, which has a longer wavelength, penetrates deeper into the skin. It does not cause sunburn, but is most significant in causing photo-ageing (ageing from the sun) and skin cancer. Photo-ageing and skin cancer are both consequences of excessive cumulative sun exposure and are almost always talked about together.
Sunlight is certainly not all bad, and generally induces a sense of well-being, decreases the appetite, improves libido and assists with the synthesis of vitamin D. We also use controlled light sources of UVB and UVA to treat a range of skin conditions like psoriasis and eczema.
The harmful effects of UV light can be divided into:
Acute (short term) and Chronic (long term effects).
Acute exposure to UVB causes sunburn which damages the DNA of our skin cells. Acute exposure to UVA suppresses the immune system in our skin which protects us against skin cancer and skin infections.
Chronic exposure to UVA causes skin ageing and both UVA and UVB cause skin cancer.
Compare the skin on sun exposed areas of your body to non sun exposed skin if you would like to see the added effect of photo-ageing to the normal process of ageing, which we call chronological ageing.
Features of photo-ageing include wrinkles, sagging skin, yellowing of the skin, pigmentation, freckles, broken veins and easy bruising.
Solar (actinic) keratosis, basal cell cancer, squamous cell cancer and melanoma are examples of precancerous and cancerous lesions.
While moderate and responsible exposure to the sun is good for your well-being, it is not possible to tan without damaging skin cells, leading to accelerated ageing, and increasing your risk of skin cancer.
Tips for sun protection
1.Minimise your exposure to direct sunlight and ensure that you never allow yourself to burn. Always seek the shade if you have to be outdoors. In general, peak UV exposure is between 11am to 3pm, but this varies with the season and location.
2. Wear a wide brimmed hat, sun protective clothing and sunglasses. Covering up is the best protection from the sun.
3. Wear sunscreens on areas that cannot be covered.
Apply sunscreen, liberally, evenly and repeatedly.
Apply sunscreen 30 min before you leave the house and reapply every 2-4 hours especially after sweating or swimming.
Sunscreens past and present.
Sunscreen technology has come a long way since the greasy, cosmetically unacceptable formulations that made you sticky and grey.
Sunscreens come in creams, lotions, sprays, milks, oils and make up compacts. They are available in tinted, non tinted and sheer forms.
The sunscreen industry has made it virtually impossible for you not to find a sunscreen you will be happy with as the worldwide consensus is the best sunscreen for you is the one that you will wear!
Sunscreen active ingredients are divided into categories of physical and chemical blockers. These protect against different wavelengths of light in the spectrum and are often found in combination to ensure maximum protection and stability of the product.
Physical blockers, titanium dioxide and zinc oxide have broad spectrum cover and are suitable for children and sensitive skins.
Older sunscreens only protected against UVB, while the newer sunscreens almost always cover UVB and UVA.