Guide to sun protection
Why should we be careful?
Nobody wants to spend the entire summer indoors, and indeed some sunshine, below sunburn level, can be good for us, helping the body to create vitamin D and giving many of us a feeling of general wellbeing as we enjoy outdoor summer activities. However, all too often we over-do our sun exposure which can lead to a range of skin problems, the most serious of which include skin cancer. Too much UV radiation from the sun can damage the genetic material (the DNA) in your skin cells. If enough DNA damage builds up over time, it can cause cells to start growing out of control, which can lead to skin cancer.
UVA & UVB
UV radiation from the sun is transmitted in three wavelengths – UVA, UVB and UVC. UVC does not penetrate the earth’s atmosphere, so we only really need to protect against UVA and UVB. Up to 90% of UV rays pass through clouds, so even when it’s cloudy, you need to protect yourself against the sun’s radiation. UVA is associated with skin ageing. UVA affects the elastin in the skin and leads to wrinkles and sun-induced skin ageing, as well as skin cancer. UVA can penetrate window glass and penetrates the skin more deeply than UVB. UVA protection in a sunscreen will help defend the skin against photo ageing and potentially skin cancer. UVB is most responsible for sunburn and has strong links to malignant melanoma and basal cell carcinoma risk (types of skin cancer). A sunscreen with a high SPF will help block UVB rays and prevent
What is sunburn?
Sunburn is skin damage and your body’s response to try to repair it – it’s a short-term warning for potential long-term DNA damage, and is a clear sign that the DNA in your skin cells has been damaged by too much UV radiation. Getting sunburn, just once every 2 years, can triple your risk of melanoma skin cancer. How does sun protection work? Organic filters absorb harmful UV radiation and convert and give this energy back out as infrared. These are sometimes known as ‘absorbers’, or ‘chemical’ sunscreens. Note that organic filters does not mean ‘organic’ in the environmental sense. Inorganic filters (also known as ‘physical’, ‘natural’, ‘reflective’, ‘zinc’) contain titanium dioxide or zinc oxide, which reflect UV radiation away from the skin. It can be helpful to think of organic filters as sponges, mopping up the UV radiation, and inorganic filters as mirrors, bouncing UV straight back off the skin.
What is SPF?
SPF stands for ‘sun protection factor’, although the SPF is more accurately the sun burn protection factor, as it primarily shows the level of protection against UVB, not the protection against UVA. SPFs are rated on a scale of 2-50+ based on the level of protection they offer, with ratings between 2 to 14 forming the least protected end of the spectrum and ratings of 50+ offering the strongest forms of UVB protection. We recommend a sunscreen with an SPF of 30 as a satisfactory form of sun protection.
Broad spectrum SPF refers to sunscreens that protect the skin from both UVA and UVB rays. Even with a high SPF (sun protection factor), if a sunscreen isn’t broad spectrum, you won’t be protected from all UVA rays.
What is a tan?
The dark pigment that gives the skin its natural colour is called melanin. Melanin is made in the skin by pigment cells called melanocytes. After our skin has been exposed to sunlight the melanocytes produce more melanin in attempt to absorb further UV radiation, and so the skin becomes darker. A tan is actually a sign that the skin has been damaged and is trying to protect itself.
There have been suggestions that vitamin D may help to prevent serious diseases such as cancer, various forms of arthritis and autoimmune diseases. This is an area of considerable research, as there are a large number of questions that still need to be answered, including whether enough vitamin D can be made from sunlight on our skin to reduce the risk of getting these diseases. On the other hand the link between skin cancer and the sun, is proven and well documented. It is safer to get your vitamin D from other sources, such as your diet and supplements.
Naturally occurring biological agents in the skin absorb a proportion of UV irradiation, melanin being one of these. Melanin is a pigment molecule in the skin and is packaged slightly differently in people of different ethnic backgrounds. People with a darker complexion have more natural sun protection, and fair-skinned individuals are more susceptible to sun burn, skin cancer and photodamage. The key character difference between black and white skin is that of melanin packaging and processing. The type of melanin of all skin colours is eumelanin except for those with red hair and freckles, who have pheomelanin, which is less well able to cope with UV irradiation. If you tan very easily you need less ultraviolet damage to initiate the tanning process. You do not need a sunscreen to stop skin cancer and skin ageing to the same extent as a fair skinned person, but sunscreen will still be needed during intense or prolonged exposure. You can still suffer from UV damage and although you are less likely to develop melanoma, your skin will age with sun exposure.
One application a day sun protection
Sun protection products which offer 8+ hours of protection from one application. It is important to remember to apply sunscreen appropriately and not too thinly. When sun protection products are tested for protection ratings they are applied correctly (liberally and regularly). Exposure to water, sweating, towel drying and any form of abrasion can remove sun protectors from the surface of the skin, keep this in mind.
How should I apply sunscreen?
The overall message in terms of sunscreen use is “more is better.” Apply sunscreen 15 to 30 minutes before going out in the sun to allow it to dry, and then again shortly after heading outdoors to cover any missed patches and to make sure you’re wearing a sufficient layer. ‘Water resistance’ is tested by the ability of a sunscreen to retain its sun protection properties following two 20 minute intervals (40 minutes total) of moderate activity in water. Another important factor is the reflection of the sun’s rays, which can greatly increase the power of the radiation, by the following percentages: snow up to 85% increase, sand up to 17% increase, water up to 5% increase.