If there is one thing we’ve noticed over the years, it’s the confusion that exists around sunscreens. From SPF ratings to the different types of UV rays and best before dates, let’s take a closer look and separate some sunscreen myths from the facts.
So, what exactly is UV?
The sun's emissions include UV, visible light, heat and other radiations. As visible light can be divided into colours which we can see in a rainbow, UV is subdivided and commonly defined as UVA, UVB and UVC. UVC doesn’t penetrate our atmosphere, so it isn’t of concern to our skin. Let’s focus on those pesky rays that do cause the most concern to our skin health – UVA and UVB
Are UVA and UVB rays the same?
UVA rays are what cause your skin to tan. They are also the cause of premature skin ageing, uneven skin tone and hyperpigmentation 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. They are often considered silent offenders as unlike UVB, you cannot feel them impacting your skin.
UVB rays are the major cause of sunburn and just like UVA also increase your risk of skin cancer. They burn the more superficial outer layers of the skin. If your skin has become red after sun exposure, or you notice discolouration or other changes to your skin’s surface, UVB is going to be the culprit.
How does unprotected sun exposure damage my skin?
UV rays penetrate beyond the surface of the skin and damage 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.”
UV rays can also trigger excess melanin production as the skin attempts to protect itself causing uneven splotches of colour commonly known as hyperpigmentation. This can occur in all skin tones even those with a higher melanin content where there is sometimes the misconception that less UV protection is necessary.
In addition to the more cosmetic side of sun damage to the skin there is undisputed evidence that shows that as UV rays penetrate, they can cause mutations that lead to skin cancer.
I’ve heard the term UV index – what is that?
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 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.
What about Vitamin D?
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 has been shown to decrease Vitamin D production. But in a laboratory environment there are 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.
