Everything about UV: from sunburn to seeking shade

Even though we generally pay a lot of attention to looking after our skin, one important factor often tends to be overlooked: UV radiation.

We usually look at ingredients, pay attention to how a product feels on the skin, and make a conscious choice when it comes to a good cleanser, serums and day and night care.

When it comes to sun protection, however, our attention often goes straight to the SPF on the packaging. SPF 30 or SPF 50 feels clear and familiar, but that number only tells part of the story.

UVA and UVB: what are they again, and what’s the difference?

Do you know that feeling when your skin feels warm, red and tight after a day outdoors? That’s mainly the effect of UVB radiation. UVB primarily reaches the upper layers of your skin and plays a major role in sunburn.

UVB also has another side: this radiation triggers the production of vitamin D3 in the skin. So UVB has two sides: the very same radiation that can burn your skin also helps your body produce vitamin D.

UVA is different. You notice this radiation much less immediately. It doesn’t necessarily make your skin red, although UVA does penetrate deeper into the skin and affects, amongst other things, firmness, elasticity and skin ageing.

A handy mnemonic is: A for UVA = Ageing and B for UVB = Burning. It’s a simplification, but it helps to remember the difference: UVA plays a major role in skin ageing, whilst UVB is more strongly linked to sunburn.

So your skin doesn’t have to be burnt to have been exposed to UV. Some of the effects of sunlight on your skin can be seen or felt straight away. Others remain hidden for much longer.

When choosing sun cream, do you look beyond the SPF?

You probably look at the SPF first when choosing sun cream. That makes perfect sense: SPF 30 or 50 is clear and easy to compare. But have you ever noticed the small UVA logo on the packaging?

SPF mainly indicates protection against UVB, the radiation that can cause your skin to burn. The small UVA logo on the packaging shows that the product also offers protection against UVA.

So that little symbol is just as worth looking out for as the big number on the front.

Why not have a look at your sun cream? Chances are you can name the SPF straight away, but do you know where the UVA logo is?

A quarter of an hour outdoors is quite different from an afternoon on a terrace

On a day off, you might pop down the high street, do a bit of gardening and go for a walk later on. None of those moments feels like a proper ‘day in the sun’, but taken together, you’ve actually spent quite a bit of time outdoors without realising it.

So the total duration of your skin’s exposure to UV counts, even if that time spent outdoors is spread throughout the day. It’s different from a single long spell on the beach or on a terrace, but it certainly adds up.

You don’t need to keep a record of it. It’s mainly helpful to realise that sun exposure doesn’t just happen when you consciously decide to sit in the sun. Even a normal day off can involve quite a bit of time spent outdoors.

How much protection does your clothing actually provide?

Clothing is an easy way to protect some of your skin from UV rays. A T-shirt, blouse or dress covers a lot of skin and can therefore be a useful addition to sun cream.

That light, airy summer blouse or dress naturally feels lovely on a hot day, but a very thin fabric usually blocks less UV than a material that’s woven a bit more densely. You don’t need to resort to heavy clothing to achieve this. A light, airy blouse made from more densely woven cotton or linen can remain comfortable to wear whilst still blocking more UV than a very thin, sheer summer fabric.

A simple way to check is to hold the fabric up to the light. If a lot of light shines through very easily, that fabric usually offers less protection against UV.

For days when you’re out and about for a really long time, UV-protective clothing can be another option. It’s specially designed to block more UV, without necessarily being heavy or warm.

How much does shade actually help?

Under a parasol or a tree, the sun immediately feels less intense. That’s pleasant, especially on hot days. However, shade doesn’t mean your skin is completely protected from UV rays.

Some of the radiation reaches you indirectly, for example through the air or by reflection from water, sand or light-coloured surfaces. That’s why you can still be exposed to UV rays on your skin even on a sheltered terrace or under a parasol.

Shade is particularly useful because it reduces direct sunlight without you having to go indoors straight away. Especially if you’re outside for a long time, it can be a nice way to give your skin a bit of a break.

When does it really make sense to reapply sun cream?

Sun cream doesn’t automatically offer the same level of protection all day long. Swimming and drying off are obvious times when reapplication makes sense, but perspiration, friction and spending a long time outdoors can also affect how well you’re still protected.

A set schedule can help, but your day itself also tells you a lot. Have you been active, gone for a swim, sweated a lot, or been outside for hours? Then reapplying is a sensible step.

What’s actually in your sun cream?

Turn a bottle of sun cream upside down and chances are you’ll be looking at a list of ingredients that makes little sense to you. Zinc oxide and titanium dioxide might still be recognisable, but when it comes to the names of other UV filters, things quickly get a lot more complicated.

Still, it’s interesting to know which UV filters are in your sun cream, as there are quite a few differences between them.

Broadly speaking, UV filters are divided into two groups: mineral and chemical filters.

Mineral or chemical: which should you choose?

In sun cream, you’ll usually find either mineral or chemical UV filters. Both types protect the skin against UV radiation, but they differ in composition and properties.

Mineral filters, such as zinc oxide and titanium dioxide, absorb a large proportion of UV radiation and also scatter or reflect a small proportion. Chemical filters absorb UV radiation and convert it into a small amount of heat, which the skin then releases.

Mineral filters

· are often well tolerated by sensitive skin;

· may leave a white cast, although this varies greatly depending on the product;

· zinc oxide can offer protection against both UVA and UVB;

· ‘mineral’ does not automatically mean that a sun cream is better for the environment. The composition of the product as a whole also plays a role in this.

Chemical filters

· often allow for lighter and more transparent sunscreens;

· vary greatly in their properties;

· there are concerns about some filters having potential endocrine-disrupting properties or an impact on the aquatic environment;

· newer chemical filters may have different properties to older generations, for example in terms of stability, UVA protection and environmental impact.

The choice is therefore less black-and-white than the terms ‘mineral’ and ‘chemical’ sometimes suggest. There are differences within both groups, which is why it makes particular sense to look at the filters used and the overall composition of the product.

Anyone consciously choosing a mineral sun cream might, for example, consider Odylique. This sun cream uses zinc oxide as a UV filter.

Protection is also about knowing your skin

Sun cream, clothing and shade all help to protect your skin from UV rays. Another part of looking after your skin properly is knowing what your own skin looks like.

If you check your skin regularly, you’ll know which moles and spots have been there for some time. This makes it easier to notice when something changes or suddenly looks different from what you’re used to.

If in doubt, a GP or dermatologist is the right person to assess such a change. A skin check is therefore not about deciding for yourself what a spot means, but about being able to recognise changes sooner.

Sun protection doesn’t have to be a complicated business

Being mindful of UV exposure often comes down to very simple choices: how long you spend outdoors, how much skin is covered, whether you can seek shade, and which sun cream you use.

If you’re familiar with these factors, you don’t have to keep figuring out what’s sensible all over again. You can simply decide each day what suits the activities you’re planning.

Taking good care of your skin isn’t just about what you put on it, but also about understanding what your skin has to cope with on a daily basis.

About the guest author

Safiera van Herk-Hoff is the founder of leefinregie.nl, a platform that was set up after her partner Arnaud was diagnosed with melanoma. That experience changed how they both view health and their daily choices. On Leef in Regie, Safiera and Arnaud share their experiences of life after melanoma, knowledge about the disease, and practical insights into nutrition, lifestyle, personal care and the living environment. Their basic premise is that health cannot be entirely controlled, but that you can consciously consider the choices that influence how you live and look after your body.

Sources

RIVM – information on UV radiation, sun intensity, UVA and UVB, and sun protection: https://www.rivm.nl/zonkracht

KWF Cancer Relief – information on UV, skin cancer and protection using sun cream, clothing and shade: https://www.kwf.nl/kanker-voorkomen/zonbescherming

Thuisarts – medically verified information on moles, skin changes and skin checks: https://www.thuisarts.nl/moedervlekken

European Commission / SCCS – scientific assessment of homosalate as a UV filter, with a focus on potential endocrine-disrupting properties: https://health.ec.europa.eu/publications/scientific-advice-safety-homosalate-cas-no-118-56-9-ec-no-204-260-8-uv-filter-cosmetic-products_en

Photochemistry and Photobiology / PubMed – scientific review of developments in modern chemical UV filters, including UVA protection, stability and environmental impact: https://pubmed.ncbi.nlm.nih.gov/41909934/