A patient recently asked whether it is really worth covering up; how much sun protection would he actually be getting from wearing a long sleeved shirt?
As a general rule, light-coloured, lightweight and loosely woven fabrics do not offer much protection from the sun. That white shirt you slip on at the beach when you feel your skin burning provides only moderate protection from sunburn, with an average ultraviolet protection factor (UPF) of 7. The sun protection lowers to an approximate UPF of only 3 when that shirt gets wet. (UPF stands for ultraviolet protection factor and is the rating system used for clothing and fabrics. It is different to the SPF system used for skin products. The UPF indicates how much of the sun’s UVA and UVB rays are absorbed. A fabric with the rating of 50 will only allow 1/50th of the sun’s UV rays to pass through)
So, what should you be looking for when choosing sun protective clothing? Not all clothing fabric is equal. You need to consider:
If you can easily see through the fabric, chances are UV can easily pass through it. The tighter the fabric structure, the better the sun protection. Tightly woven, lightweight natural fabrics such as linen, cotton or hemp will also help keep you cooler than synthetic fibre equivalents.
If a fabric is stretched, it will be less protective. This is common in knitted or elasticised fabrics.
Layering of fabrics and garments is an effective way of increasing protection from UV.
Darker colours absorb UV rays better than white or pastel colours of the same fabric.
Fabrics offer less protection from UV radiation when wet. How much less protection will depend on the type of fabric and the amount of moisture it absorbs. To reduce the effect of the moisture, take dry clothes to change into or if dipping in and out of the water, choose a fabric that provides effective protection from UV and that will dry quickly.
Caring for your clothes:
Washing new clothes can improve their sun protectiveness by shrinking gaps in the structure. However, old, threadbare or faded clothes may offer decreased protection over time.
Some clothing is treated so it can absorb more UV radiation. Check the clothing label to see if your clothes have been treated and follow the care instructions.
Source: Cancer Council Australia, Coolibar