Summer rolls around every year and millions of people travel to hot, sunny destinations all over the world – unless you’re lucky enough to live in a hot climate unlike us Brits! Everyone loves to spend a little time in the sun, but as most of us know – you can have too much of a good thing! It’s common knowledge that the sun’s powerful rays can be harmful, but why exactly should we avoid too much sun? The Geeks are here to shed a little (sun)light on the subject!

A little about UV to start
UV rays are a kind of radiation – most of us know about them from a tanning point of view, but did you know there are two main types of UV that reach the earth. UVB, also known as ‘short-wave’ UV is the one you’re probably thinking of, and is responsible for sunburn. UVA on the other hand (also known as ‘long-wave’ UV) is not as powerful as UVB, but can penetrate deeper into the skin to affect the layers further from the surface. There is also a form of UV known as UVC, which is incredibly powerful, but thankfully does not reach the surface of the earth.

How do these types of UV relate to tanning and SPF?
Both UVA and UVB contribute to tanning – UVA activates melanin (the skin’s natural pigment) that’s already present in the skin cells, whilst UVB triggers the production of more melanin, which contributes to a more lasting tan.

Sun protection factor (SPF) is effectively a measure of how much longer you can stay in the sun without getting burned. Because it’s UVB that’s responsible for sunburn, SPF is only really a measure of protection against UVB, and doesn’t reflect how much protection you get from UVA radiation. SPF 15 blocks around 93% of UVB rays, and is the recommended minimum by many sun-awareness organisations. When shopping for sunscreens, it’s important to seek out products labelled as ‘broad-range’ sunscreens, as these protect against both UVA and UVB.

If UVA doesn’t cause sunburn, why do we need to protect against it?
It’s been known for a long time that UVA contributes to the accelerated ageing of the skin due to sun exposure (commonly known as photoageing), which includes visible signs of ageing like skin sagging and wrinkling, as well as dryness and patchy pigmentation. Studies have shown that UVA exposure causes oxidative cell stress in skin cells, which itself is thought to underlie ageing. UVA exposure also increases the levels of enzymes called MMPs, which are known to degrade proteins that are key for maintaining the skin’s structure and elasticity, including collagen and elastin. Aged skin is associated with decreased levels of these proteins, so avoiding damaging UVA rays is a top anti-ageing priority.

Increased exposure to UVA, like UVB, is known to increase the risk of developing skin cancers like melanoma, so choosing a broad range sunscreen really is a must!

We hope that’s answered some questions about sun exposure and why it’s better not to let yourself bake in the sun! If you have anything you’d like us to elaborate on, we’d love for you to get in touch by either leaving a comment below or tweeting us @BeautyByGeeks!

“New insights in photoaging, UVA induced damage and skin types.”
“Understanding UVA and UVB” – The Skin Cancer Foundation
“The known health effects of UV” – World Health Organisation
“Photoaging of the Skin”
Image (thank you!):