Last updated: March 2020
Doesn't all clothing block the sun?
Often, experts will suggest covering up with a swim shirt, wide brimmed hats, and more when outside, however, there's actually a lot more to clothing and its potential to shield harmful rays. Intuitively, it makes sense that the more clothing worn, or the more covered an individual's body is, the more protected they are against the sun's rays. Although this can be true, it's important to note that not all articles of clothing, nor their fabrics, are created equal when it comes to shielding harmful radiation.
As a basic example, one individual may be wearing a loosely woven, long-sleeved, bleached cotton shirt, while someone else may be wearing a tightly woven, shiny, nylon, short-sleeved shirt. Although many factors need to be considered, it may be that the person in the short-sleeved shirt has more protection, as the fabric they are wearing is tightly woven and reflective over the areas of their body that the garment covers.
Tightly woven, shiny articles of clothing made of synthetic fibers may protect against and reflect more UV rays than a loosely woven, bleached cotton or linen piece.1,2 While more clothing often means more protection, it is important to consider the quality of the clothing worn in relation to its ability to block out the sun's radiation.
Have you ever used UV protective clothing?
What is UPF clothing?
UPF is one way to measure the quality of an article of clothing or fabric in regards to its ability to protect against the sun. UPF stands for Ultraviolet Protection Factor, and unlike SPF, which is a measure of protection against UVB rays only, UPF takes into account a fabric or article of clothing's ability to shield both UVA and UVB rays.
UPF is a standardized metric used all over the world, and is often present on many different articles of clothing. Not every clothing item available will have a UPF label. Further, any garment without a specific UPF label or value does not mean that it is unable to protect against the sun or that you shouldn't buy it. The UPF label is just a way to make informed and confident clothing choices.
What is a good UPF value?
A garment's UPF value is a number that coincides with the fraction of UV rays it allows to pass through and hit your skin. The higher the UPF number, the better the protection. For example, a UPF of 30 allows 1/30th of the sun's UV radiation (3.3%) to pass through it. A UPF of 10 would allow 1/10th of the rays (10%) to pass through it.
UPF values of 15-20 are considered good, 25-35 is considered very good, and 40+ is considered excellent. Clothing items rated below UPF 15, such as a white cotton t-shirt rated UPF 5, are not considered protective against UV radiation. Properties that affect a fabric or garment's UPF rating include chemical treatments, dyes, fiber type, color (darker colors generally protect better), and denseness or thickness of base material.1,2
How interested in protective clothing are you?
Caring for your UPF clothing
When considering what garments are the most sun-safe, or when deciding what articles of clothing to wear or purchase, there are some tips and tricks to consider. Some of these include:Shrinking articles of clothing in the dryer before wearing often tightens the weave of fibers within the fabric leading to better protectionStretching articles of clothing, or wearing clothing that is too tight, such as body-hugging leggings, reduces the UPF value of the fabric it's made out ofUPF-enhancing or protecting detergents exist and can be used to potentially increase a garment's protective valueWhen a garment is wet, its UPF value is often negatively affected. Wearing quick-drying fabrics may help protect an individual better should their clothes get wet or if they are participating in an outdoor water activityUPF-protective garments can come in all shapes and sizes, and suit a variety of purposes. Although coverage of more skin can be better, it is possible to cover up and still wear breathable fabrics or swim shirts to participate in outdoor, warm-weather activitiesWearing hats that are wide-brimmed as opposed to baseball hats can lead to more protection1,2
Do you sunscreen in the fall?