Aug. 19, 2013 at 2:19 PM ET
A lot of workout clothing advertised as "antibacterial" or "anti-odor" contains microscopic particles, or nanoparticles, of silver. These particles, shrunk down to sizes as small as one billionth of a meter, are natural bacteria-killers that can prevent odor- and mildew-causing bacteria from ruining your pricey workout gear (and your pride).
Sounds great, right? Except that silver nanoparticles aren't bound to that antibacterial clothing, and the teeny particles slough off every time you wash your sweaty clothes. And, according to a new study in the journal Environmental Science & Technology, they get absorbed by your skin when you sweat, exposing you to untested, and potentially unhealthy, levels of this metal.
Silver nanoparticles have never been tested for safety when used in consumer goods, yet the Pew Charitable Trust's Project on Emerging Nanotechnologies has so far calculated that 244 consumer products contain them, ranging from cutting boards to bath towels to athletic clothing. Even though silver is a natural material, and has been used for medicinal purposes in non-nano form for centuries, silver nanoparticles have been shown to damage lung, liver and kidney function in animals.
For this most recent study, scientists were trying to determine how much nano-silver people are exposed to from treated clothing under real-world conditions. So they simulated the kind of wear-and-tear that these clothes items undergo when worn by sweaty, active people by exposing the clothes to artificial human sweat and placing them in a washing machine, where the clothes were exposed to heat and agitated for 30 minutes. Using the results of this test, they estimated how much silver your body might absorb via sweat glands.
The researchers said that exposure to silver would be "significant" for anyone wearing these clothes, in an amount that's three times higher than the amount you'd get if you take a dietary supplement that contains silver. Even though scientists are still uncovering the health risks associated with nano-silver, the National Institutes of Health warns that getting exposed to too much silver of any kind is unhealthy. The metal is often touted as a cure-all for a wide variety of conditions and getting too much in your system can lead to a condition called argyria, an untreatable, irreversible condition that causes a bluish-gray discoloration of the skin.
In addition to putting you at risk for weird skin colors, this study adds to evindence that nano-silver-treated clothes are a toxic ripoff. A 2010 study in the journal Environmental Science & Technology found that anywhere from 20 to 50 percent of silver nanoparticles on treated clothing washed off the first two times various types of clothing were laundered.
If you're worried about smelly workout clothes, ditch the antibacterial clothing and try nature and common sense to keep them from becoming too malodorous:
Pretreat. Before you wash your smelly gym clothes, sprinkle some baking soda on them, leaving it on for about an hour before laundering them to remove perspiration odors as well as stains.Launder with care. Because sweat can be oily, it can build up on clothing, becoming difficult to remove with regular detergents and water. Add a cup of white vinegar to the rinse cycle; vinegar helps break through oils on fabric, and it serves as a deodorizer. Or hand-wash your clothes with shampoo, which is designed to cut through body oils.Line-dry. Nothing cuts through bad odors like oxygen and sunlight. Let your clothes dry outside, rather than in a machine, and you'll save energy, make your clothes last longer, and prevent offensive odors the next time you hit the gym. This or That: Liquid or Powdered Laundry Detergent?