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Do You Know Your UVA From Your UVB?

Updated: Jul 31, 2023

When it comes to the British weather, on those rare days when we get wall-to-wall blue skies there’s a real temptation to soak up the sun – and that’s when we need to be aware of the damage it can cause.

Know Your UVA From Your UVB

There are very few of us who wouldn’t dream of chilling by the pool on holiday without slathering top to toe in SPF. But I’m still surprised how many people don’t think they need to be doing the same in this country. I totally understand that we all feel better with a tan, but long hours of sun’s UV rays really does take its toll on our skin.

What Are UV Rays?

UV is the ultraviolet light given off by the sun that is invisible to the human eye. Depending on their wavelengths, they are officially categorised as UVA, UVB, and UVC (the shortest rays absorbed by the ozone layer). The UV Radiation Index measures the intensity of the sun, with 3-5 being moderate; 6-7 is high; 8-10 being very high; and anything over 11 is seen as extreme.

UVA: This is the longest of the three rays and is recognised as the one that causes our skin to age. UVA penetrates through the clouds and even windows, through to our dermis (the layer of skin that lies beneath the epidermis). A recent study in southern France found those over 50 who spent time in the sun without protection had more wrinkles and pigmentation issues than those of the same age who had adopted safer sun habits. In fact, the research revealed that sun exposure accounted for a staggering 80% of the visible aging observed. This is because prolonged exposure actually shrinks collagen and elastin fibres, and this in turn causes lines, wrinkles and loss of elasticity. Interestingly, the amount of UVA exposure doesn’t change whatever the weather or the time of the year.

UVB: These rays cause sunburn and their intensity depends on the time of the year and time of day. They penetrate the epidermis (the top layer of your skin) and stimulate melanin – it’s why we get freckles; the more time you spend in the sun, the more melanin is produced. Too much UVB exposure though and you’ll suffer sunburn as our bodies fight to reverse the damage, blood vessels dilate to increase blood flow to the affected area, causing redness and swelling.

Protect Yourself

While it may sound strange to wear SPF all year round, that is exactly what you should do, ensuring you go for a higher factor as the UV Index rises. SPF helps your skin tolerate the sun’s rays and as a general rule of thumb is, if you skin goes red within ten minutes then an SPF30 means it will take 30 times longer for this to happen, while a SPF50 allows even longer outdoors. However, the SPF only measures protection against UVB rays, so you need to ensure you stock up on a broad spectrum sunscreen that protects against UVA too.

Julia is one of the region's leading Consultant Ophthalmic Plastic, Reconstructive and Cosmetic surgeons and is Director of the Dr Julia Sen Health & Wellbeing Clinic in Worcester . Visit her website here to find out more.

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