.........we all scream when sunscreen doesn't work!
The problem is probably not with your sunscreen, but what you are expecting it to do for you!
To understand why you get burnt despite being good with the sunscreen, it is important to know a couple of things:
Sunscreen can’t block out the Ultra Violet Radiation (UVR) completely, so regardless of you wearing sunscreen, some UVR will penetrate your skin, even if your product has physical barriers such as Titanium or Zinc.
SPF is the Sun Protection Factor, and the number quoted is the amount of times protection you get over and above your natural burntime – e.g. if you would normally burn in around 10 minutes (as your bog standard Aussie skin does) an SPF 30, with give you around 300 minutes before you get to the same level of burn.
The problem is that the skin can only absorb so much UVR before it starts to burn. And once the damage has started, adding more sunscreen on top isn’t necessarily going to help. Think of it like a bit of meat on the BBQ. When you put something on that takes 20 minutes to cook, it doesn’t come off after 18 minutes still stone cold and suddenly cook when the clock hits 20 minutes.
When you put on SPF 30 this gives you 300 minutes until you start to burn, so 150 minutes later you are halfway there. Even if you re-apply the sunscreen your skin has already taken some punishment and won’t go back to square one today.
If you know you are going out in the sun for the whole day and you don’t want to get burned, start with a very high factor sunscreen and after a while you have no choice – seek shade and cover up!
The shady side of sun protection
There is more to meets the eye when it comes to shade too. Sitting on the beach in the shade of your umbrella this summer might not be giving you the protection you think. Most of us are well aware of the need to use sunscreen but often we sit in shaded areas without sunscreen for an hour or longer reading a book or just relaxing.
In summer, UV intensity in Australia is 50% higher than at the same latitude in Europe and has increased in the last ten years because of environmental changes. Shade provides immediate relief from heat and the intensity of direct sunlight but its ability to provide protection from UV radiation is more limited than most people realise.
UV radiation bounces of atmospheric particles and is scattered in various directions. In other words it doesn’t come down in a straight line and stop at your beach umbrella. As a result small shaded areas are a high-risk for people without sunscreen.
So what about trees? The Queensland Institute of Medical Research in Brisbane deduced a fair skinned person sheltering under a tree could suffer sunburn in less than an hour. An average pine tree provides a SPF factor of around 3.7, in other words 37 minutes until burn time. Only trees with thick foliage that completely cut out the sun give better protection.
Does this mean seeking shade is not worthwhile? Not at all. If you wear sunscreen on your face with an SPF 15 and you sit under a tree with an SPF 3, the full effect is an SPF factor of 45. In short, sit in the shade, don’t forget the sunscreen, but most important of all, cover up!
