The importance of SPF
Sun protection factor (SPF) is the level of protection given by a sunscreen against UVB rays. UVB is one type of UV radiation the sun emits and is the one than causes us to burn. The other type is UVA, which is associated with skin aging. A good sunscreen will contain protection against both types of rays. There is a third type of UV radiation too – UVC rays – but these are filtered out by the atmosphere before they reach us, so are not something you need to worry about, thankfully!
The problem with UVA rays
The majority of the sun’s rays – around 95% – are UVA rays. These have a shorter wavelength and penetrate the skin more deeply. The SPF rating factor you see on bottles of sunscreen refers specifically to UVB rays. For protection against UVA rays it’s important to pick a sunscreen that offers ‘broad-spectrum protection’, meaning it protects against UVA rays too.
UVA rays are responsible for signs of aging such as dark spots, pigmentation, wrinkles, loss of elasticity and dry skin. Damage is cumulative, meaning that all sun exposure will build across your lifetime. Excess sun exposure in your youth will therefore effect you in your older years. That doesn’t mean that if the damage is already done you may as well carry on sunbathing though. Being cumulative, unfortunately damage can continue – but there are ways to minimise this.
The problem with UVB rays
UVB radiation makes up just 5% of the UV rays from the sun, but they are the ones that cause the most instant and visible damage. If you are exposed to them for too long and without adequate protection, you will burn. The most obvious result of this is hot, red and painful skin that will ultimately blister and peel. These rays don’t penetrate to the same depth as UVA rays, but they are high energy and cause significant damage on the top layers of your skin.
As well as the visible damage to your skin, UVB can damage skin cells and result in DNA mutations that can eventually lead to melanoma and other types of skin cancer. It’s normal for new moles to appear as you age. Likewise, it’s normal for them to sometimes fade or disappear. Moles are often quite normal and pose no threat, but if you have any new moles or existing moles that seem somehow different to others it’s always best to get them checked. The NHS lists these differences as:
- A mole that’s changed colour, darkened or has more than two colours
- A mole with uneven borders or one that changes shape
- A mole that’s bleeding, itching, crusting or flaking
- A mole that gets bigger or is raised from the skin
How to use SPF to prevent sun damage
It doesn’t have to be hot, or even sunny, for the UV rays from the sun to penetrate your skin. Even if you don’t burn, the sun can cause damage deep within your skin and lead to dry skin, premature aging and wrinkles. If in doubt as to whether you need sunscreen, just go by the mantra ‘if you can see, then there’s UV.’ Quite simply, if it’s daylight, there will be UV rays reaching your skin. It can feel good to have a tan, but it’s important to be aware that a tan, as well as sunburn, is a sign of damage to your skin.
The most important step in protecting your skin is to wear a good quality sunscreen with a high SPF daily – even in the winter. That means an SPF of at least 25. Broadly speaking, the number represents the amount of protection you receive compared to no sunscreen. So factor 25 would hypothetically enable you to stay in the sun for 25 times longer than you would unprotected without burning. If you would usually start to burn in ten minutes, this would give you 250 minutes, or just over 4 hours. However, this is assuming there are no factors to compromise the effectiveness of your sunscreen. In practice, it is likely to start sweating or rubbing off before then. You may miss bits when you apply it. Some could come off in a pool or the sun – even waterproof sunscreens should be reapplied after swimming. It’s also important to allow 30 minutes after application for it to penetrate your skin and work optimally, so putting it on for the first time as you sit by the pool isn’t recommended and you should really apply it before you leave your room.
What other ways can you protect yourself from the sun?
Wearing SPF is not the only factor within your control. The sun is at its strongest between 11am and 3pm. This is a good time to seek shade, particularly in the summer. Staying in the shade doesn’t mean you can forgo your sunscreen though as UVB rays (the ones that burn you) can bounce off reflective surfaces like sand, water and concrete. UVA rays can also penetrate clouds and windows.
Also, wear a hat and sunglasses and remember to reapply your SPF if you swim, sweat or spend an extended period of time outside. Don’t forget to apply it on the commonly overlooked areas, like your hair parting and ears – both of which are particularly painful if they burn.
If you miss that summer glow, there are numerous bronzing products that can help you safely emulate a suntan in an instant – and in the long term, your skin will thank you for it.