There’s a widely recognized connection between sun exposure and skin damage. Most people understand that sun-damaged skin is vulnerable to the development of skin cancers. Additionally, too much time in the sun leaves the skin prematurely aged and wrinkled. Sunscreen is high on the list of holiday essentials.
But, while public awareness of this issue is generally high, there remains some confusion about the precise meaning of “Sun Protection Factor” (SPF) and the effectiveness of SPF-labelled products. Typically, these include sunscreens and some clothing designed for outdoor activities and sports. This article aims to clarify these issues and help in your choice of sunscreen and clothing.
Read the Labels on Sunscreen Products – Look for SPF and a Star Rating
The Sun Protection Factor (SPF) is a measure of how well a sunscreen will protect skin from ultraviolet B (UVB) rays. UVB is the primary cause of sunburn and it contributes to the development of skin cancer. SPF does not, however, measure protection from ultraviolet A (UVA) rays, which can also cause damage and ageing of the skin.
Thus, it is essential to choose a broad-spectrum sunscreen that protects against both UVA and UVB rays. Check the label to ensure your sunscreen does both. The SPF indicates the level of protection from UVB. A star rating (out of 5) indicates protection from UVA. Sometimes there is an A in a circle, which matches EU labelling regulations for UVA protection.
Hours and Minutes, or Quality of Protection?
With UVB protection, the SPF number represents the theoretical amount of time you can stay in the sun without getting sunburned, relative to unprotected skin. For example, if you apply an SPF 30 sunscreen properly, you should be able to stay in the sun 30 times longer without burning than if you were not wearing any sunscreen. Thus, SPF 30 has been associated with a guideline of 300 minutes, and SPF 50 with 500 minutes, i.e. just over 8 hours accordingly – compared to a notional 10 minutes in the sun without sunscreen. However, the actual protection delivered is influenced by several factors, including skin type, the intensity of sunlight, and the amount of sunscreen applied.
Another way of looking at it is the depth or quality of protection. Generally, SPF 15 sunscreen blocks 93% of UVB radiation, and SPF 30 blocks 97%. Incremental protection is small after that, but can nevertheless be very important. SPF 50 blocks 98%, and SPF 100 stops 99% of UVB rays from reaching your skin. However, this description can create a false sense of security, especially in conditions of prolonged exposure to strong sun.
Whichever analysis you prefer, it remains the case that the SPF (UVB) and star ratings (UVA) are only two factors in ensuring effective protection against skin damage.
Context is All-Important
On both the above measures, the stronger the sun, and the longer you are exposed to it, the better the protection you should use. Also, the more frequently sunscreen should be re-applied. In the UK, the sun’s UV rays are often strong enough to cause damage between mid-March and mid-October, so if you’re heading off to a sunshine destination, you definitely need sunscreen. It is essential to consider the context of where you are. What time of day are you exposed to the sun, and for how long? As anyone who has been seriously sunburnt will know, to provide protection it’s worth being extra cautious and using clothing, a hat, and good quality sunglasses, as well as sunscreen. Always err on the side of caution.
Frequently Asked Questions about Sunscreen and SPF
Can I still develop a suntan while using a strong sunscreen?
Yes, to a certain extent. Sunscreen is designed to filter out harmful UV rays, but some still penetrate the skin, which can result in a tan. However, a tan achieved while wearing sunscreen will typically develop more slowly and be less intense than one achieved without any protection.
Does a strong sunscreen inhibit my skin’s ability to produce Vitamin D?
Sunscreen does not completely prevent the production of Vitamin D. However, it does reduce it. For most people, regular short exposures to the sun without sunscreen, combined with a diet that includes Vitamin D, will be enough to maintain healthy levels.
Can sunscreens be truly waterproof?
In reality, no sunscreen is completely waterproof. Products labeled as “water-resistant” are tested to remain effective for a certain amount of time while swimming or sweating. The labels usually specify whether the sunscreen remains effective for 40 or 80 minutes while in the water. It’s important to reapply sunscreen regularly, especially after swimming or drying off with a towel.
Can I use last year’s sunscreen?
The effectiveness of sunscreen can diminish over time. Generally, sunscreen remains effective for about three years from the date of manufacture, which means that last year’s sunscreen could still be effective if it has been stored properly and is within its use-by date. However, if the sunscreen has changed colour, consistency, or smell, discard it and purchase a new bottle.
Is it true that naturally dark-skinned people cannot get sunburned?
No. Darker skin and skin of colour has more melanin, and that does offer some protection against UV rays. However, these skin types are still susceptible to sunburn and skin damage. Therefore, people of all skin tones should use sunscreen.
Surely, most clothing provides protection from the sun. Why is some given an SPF/UPF?
All clothing will provide protection from the sun, but not all equally. A closely woven shirt or top will provide more than a thin beach wrap. Some clothes come with an SPF number referred to as Ultraviolet Protection Factor (UPF). This indicates how much UV radiation a fabric allows to reach the skin. For example, a UPF 50 fabric should block 98% of the sun’s rays. Such clothing is good for extended outdoor activities when sunscreen alone might not provide enough protection. If you buy clothing with a UPF indicated, make sure it is from a reputable source, as some brands may use claims of sun protection as a marketing tool rather than an inherent quality.
Do I need sunscreen on a cloudy day?
Yes. Even on cloudy days, up to 80% of the sun’s harmful UV rays can penetrate the clouds, making sunscreen necessary regardless of the weather. It is a common misconception that sunscreen is only needed on sunny days.
Where can I find out more?
Check out these useful links:
- Cancer Research UK: “Sun Safety”
- NHS: “Sunscreen and Sun Safety”
- British Association of Dermatologists: “Sun Protection”
- World Health Organization: “Sun Protection and Sunscreens”
Enjoy the sun, safely
Being smart in the sun involves understanding that an SPF number on its own may not guarantee protection from harm. Adjust the choice and use of sun protection to the conditions. Consider the expected temperature, the time spent in the sun, and whether you’ll be swimming, or exercising enough to sweat. Factor in that you may be towelling yourself dry, and the delicacy of your skin. By choosing the right products and applying them correctly, you can enjoy your time in the sun while confidently minimizing the risk of skin damage. Stay informed, stay protected, and enjoy your sunshine destinations safely.
By Declan Morton, writer and editor at Essiell Ltd and Money4Travel.
More about the author.
