UV is separated into three types; UVA, UVB and UVC. UVC generally does not penetrate our atmosphere though so it’s not really of concern here.
UVA rays are what cause your skin to tan. They are also the cause of premature skin ageing and can heighten your risk of skin cancer. About 95% of the UV rays which reach our skin are UVA, and they are present even on cloudy days. UVA rays also penetrate glass, and, unlike UVB, you cannot feel them impacting your skin.
UVA penetrates deep into the dermis and damages the collagen fibres. This damage results in your body producing abnormal elastin and degraded collagen, which leads to your body making mistakes when it rebuilds your skin. As this continues to occur, the incorrectly rebuilt skin begins to form wrinkles, while the depletion of collagen causes it to become “leathery”.
As UVA rays penetrate into the basal layers of the skin, they can cause mutations which then result in skin cancer. Tanning beds, which are now illegal for commercial use in Australia due to their well-documented links to skin cancer, can emit UV radiation three times as strong as the midday sun in summer. More on that here.
UVB rays are the major cause of sunburn and also increase your risk of skin cancer. They burn the more superficial outer layers of the skin. If you have gone red after sun exposure, or you notice discolouration or other changes to your skin’s surface, UVB is going to be the culprit.
Just like UVA, UVB is also always present; however there is far more of it around in sunny environments – like Australia – and higher altitudes (which is why you might find yourself getting burnt when on the ski slopes). The intensity of UVB varies depend on where you are and the time of day.
Back in 1992, Canadian scientists developed a scale known as the UV index. It measures the likelihood that UV radiation will cause your skin to burn; which means it is measuring UVB rays. Health officials generally recommend you should apply sunscreen if you are going to be outdoors when the UV index is at 3 or above. Finding out what the UV index is on any given day is quite easy – in Australia you can find this information by checking the UV forecast on the Bureau of Meteorology website or app.
When our skin is exposed to UV rays, our bodies use this to create Vitamin D, which helps us to regulate calcium levels in our blood and to keep our bones, muscles and teeth healthy. There is a myth that wearing sunscreens which protect us against UV rays can cause us to become deficient in Vitamin D. Yes, in lab conditions, sunscreen was shown to decrease Vitamin D production. But think about a laboratory environment; there is no UV rays from the sun! When put to the test in real world circumstances, it has been proven to have very little impact on Vitamin D production. You can read more on this at the SunSmart website.
Now we understand the differences between the two main types of UV rays and when we need protection, let’s delve into the confusing world of SPF (sun protection factor).
First and foremost, it’s important to understand that the SPF rating on a product is referring to the protection it provides against UVB rays. Not UVA. Before you panic, the answer to the question we know is on the tip of your tongue right now is that in order to protect against both UVA and UVB rays, you are going to need a broad-spectrum sunscreen. More on that later.
Let’s jump back to SPF for now though. What it measures is the amount of time the sunscreen you have purchased will protect you from UVB rays before your skin starts to burn. It also gives an indication of the percent of UVB rays it can screen you against. Let’s take a look at the most common SPF ratings in Australia.
SPF 15: Blocks 93% of UVB rays. Takes 15 times longer for UV rays to begin burning your skin, as compared to bare skin. Great for your average day at the office with a few outdoor errands.
SPF 30: Blocks 97% of UV rays. Takes 30 times longer for UV rays to begin burning your skin, as compared to bare skin. Great for if you’re going to be outdoors a bit more.
SPF 50: Blocks 98% of UV rays. Takes 50 times longer for UV rays to begin burning your skin, as compared to bare skin. Great for days when you’ll be spending a lot of time outdoors.
As we mentioned above, broad-spectrum sunscreens provide protection against both UVA and UVB rays, whereby helping to reduce your risks of sunburn, premature ageing and skin cancers. In order to do this, they will contain a combination of different ingredients protecting against different types of UV.
How much sunscreen do I need and how often should I apply?
When SPF testing is conducted, the sunscreen has been applied “liberally”. Unless you can say the same of your application method, you’re not going to get the full benefits of the sunscreen you have applied. The Cancer Council recommends an average adult will need one teaspoon of sunscreen each for their head and neck, each limb, the front and the back of the body. That’s about 35ml for a full body application.
It’s also of utmost importance that you continue to re-apply sunscreen during the day if you are out and about. Why? As we swim, sweat and move about, the sunscreen will begin to wear off. Plus, as we discuss above, it only protects you for a certain length of time. You can only guarantee your protection by continuing to apply ample amounts; the Cancer Council recommend you do this every two hours, and after you have been swimming or sweating excessively. We know how easy it is to forget to do this when lapping up a glorious day at the beach or enjoying a midday BBQ with friends at the park! Perhaps try setting a reminder on your phone if you think you need it.
Look for the best before
Did you know that sunscreen goes out of date? It’s true, like the majority of skincare products. If the tube you’ve just dug out of the bottom of your beach bag from last summer is past its best before, get a new one! Sun protection is serious business (if you haven’t already gathered from this lengthy and informative overview), and you don’t want to risk the health of your skin with a product that can no longer provide you with the protection you deserve.
The Australian-made factor
The UV levels reaching our ‘sunburnt’ nation are considerably higher than those affecting Europe or North America, and thanks to Australia being physically closer to the sun during our summer months, we can end up being exposed to as much as 15% more UV.
Because of this Australia has stricter standards for sunscreens than anywhere else in the world, meaning that an Australian sunscreen is going to give you some of the best protection possible. In order to tell if the sunscreen you are looking at is Australian, take a look to see if it has an AUST L number.
Further to this, you should also be wary of products which are not TGA approved, aren’t actually a sunscreen or are homemade; we’ve heard ludicrous statements such as “carrot oil as an SPF” or ‘it’s about building an immunity to the sun’. These products or statements won’t have been properly tested for effectiveness and may not provide you with proper sun protection. Need we say more?