Most smart people on the beach these days wear sun protection clothing, in and out of the water. It looks like wetsuits or rash shirts used by surfers, made out of lycra which protects the skin from ultraviolet light better than anything else.

Clothing, wet or dry, should be part of a comprehensive sun protection programme that also includes hats with a wide brim all around, eyeglasses that block ultraviolet radiation, sunscreens with SPF 15 or higher for face and hands, and shade, especially between 10 am and 4 pm.

Be 'Clothes' minded when you go swimming

For swimming wear a full length lycra bodysuit or a swimshirt and leggings or boardies or bike shorts, and maybe special beach shoes. These are easy to swim in and dry quickly.

For boating and other outdoor activities you may want to wear quick drying sportswear with a hooded top and long tracksuit pants or robust jeans. If you make sure that it all fits well and doesn't slip down, you'll have a great outfit for fun in and out of the water.

In Australia it is rare these days to see a kid wearing just swimmers (like speedos) or just boardies on the beach. Most teens think that sun protection clothing is cool, but many will wear a rashie and boardies rather than a sunsuit.

Wet clothing loses some sun protection

Wet clothing also poses a problem, with some fabrics, such as cotton, losing up to 50 percent of their SPF. In Florida, for example, it's common practice for parents to put a white T-shirt on their children to protect them from the sun while swimming. What parents don't realise is when this T-shirt gets wet, it actually provides very little sun protection.

Darker clothes protect you better

Darker colored fabrics are better than lighter colors for increased sun protection. For instance, the SPF of a blue cotton T-shirt is 10 versus 7 for white cotton T-shirt which provides only moderate protection from sunburn, less when wet.

At the other end of the spectrum, a long-sleeve dark sweatshirt and denim jeans offer excellent sun protection. Even when wet you get an estimated SPF of around 50.

An easy way to test the amount of sun protection in an article of clothing is to hold it up to a light or window and see how much light passes through the fabric. If a lot of light passes through, it will not provide adequate sun protection and you should opt for a more opaque fabric.

UV Absorbers

Treating fabrics with UV-absorbers such as resins is another common way for clothing manufacturers to increase the SPF of clothing. Recently, specialised laundry detergents that contain sun-protective additives have been introduced to give consumers a temporary way to increase the SPF of clothing between washes.

Two other factors can alter the SPF of clothing are whether the material is stretched or worn wet. Any article of clothing that is stretched in certain areas loses some level of UV protection, because the fabric becomes thinner and more transparent to light.

Know the right fabrics

If you work, swim or play in the sun you should choose clothing that offers UV protection. It's a misconception to think that every form of clothing provides enough sun protection to prevent sunburn. Most of the summer clothes we wear would not get high marks for sun protection. But knowing what types of fabrics and colours to look for is a good start.

Several factors determine the effectiveness of clothing in blocking harmful UV rays, including fabric construction, fibre content and weave, fabric color, finishing processes and the presence of additives. Clothing made of tightly-woven fabric performs the best at protecting skin from the sun. Woven fabrics that have see-through holes between individual threads allow UV rays to penetrate through to the skin and are not recommended for sun protection.

There are a number of factors to consider when selecting sun protection swimwear. The most important factors affecting sun protection are skin coverage, fabric, and fit. Sun protective swimwear is typically used in a highly intense UV environment, at the beach or at the pool during summer.

The best approach to protection from the sun in this environment is a combination of SPF swimwear, sunscreen, and shade. As a general rule, the greater skin coverage through uv protection swimwear, the less the area that needs to be protected by sunscreen that wears off and needs to be continually reapplied. UV protective swimwear that fully covers your shoulders and arms like long-sleeve swim shirts (and swim tights for legs) is the best choice for guaranteed all-day protection.

The fabric used to make sun protective swimwear is important for a number of reasons. The best UV protective swim wear fabrics will be rated UPF 50+ based on a complete life cycle test when the fabric is wet. Sun protective fabrics will typically lose some of their protection as they age, so garments should be tested for their end of life cycle protection value.

Other fabrics also provide less sun protection when wet. This is because water displaces air in the fabric and UV transmits better through water than air. A recent modification to the AATCC 183 protocol for testing SPF swimwear calls for testing the fabric when wet, providing a better evaluation of the protection level when the garment is used in water as intended. So the best SPF swimwear will provide UPF 50+ protection when wet at the end of it’s life cycle.

Fit is important for appearance, comfort and sun protection levels. For many people, their first thought is to choose tight fitting swim shirts, just like the original rash guards or rash shirts worn by surfers. However, when stretched the weave of a fabric will open and can allow significant amount of UV to pass through the fabric. For this reason, choose sun protective swimwear that is designed to be worn close to the skin, but not to be skin tight.