Time to Ditch Your Toxic Workout Wear? The Health Hazards Hiding in Your Activewear

The stretchy, sweat-wicking workout clothes that make exercising comfortable contain hidden health hazards. New research shows that the synthetic fabrics commonly used in activewear can leach potentially toxic chemicals onto your skin when you sweat.

Scientists at the University of Birmingham in the UK found that the oil in human sweat acts as a conduit for chemical additives in plastics to dissolve from fabrics and be absorbed into the body. Their study focused specifically on flame retardants added to some textiles. However, the findings likely apply to other plastic chemicals like bisphenols and PFAS commonly used in workout clothes.

With repeated exposure from frequent sweating, these substances can accumulate in the body over time. Experts say this is yet another route we absorb harmful contaminants from plastics, in addition to ingesting them through food and drink.

Activewear is often made of synthetic materials like polyester and Spandex, a type of elastic polyurethane. These petroleum-derived fabrics utilize hundreds of chemical additives in the manufacturing process, from plasticizers that enhance flexibility to dyes that provide color.

Many common ingredients in workout clothes have known links to health problems. Phthalates, which make plastic more pliable, are associated with reproductive issues and diabetes. Bisphenols can disrupt hormones and increase heart disease risk. PFAS repel water but persist indefinitely in the environment and body. And because brands aren’t required to disclose everything used along opaque global supply chains, other untested substances likely lurk as well.

When we sweat during exercise, oils and lipids come to the surface of the skin. Study author Dr. Mohamed Abdallah said these oily secretions “help the bad chemicals to come out of the microplastic fibers and become available for human absorption.” So, the more you sweat in your synthetic workout clothes, the greater the chance chemicals leach out. Over time, Abdallah said, “You may be exposing yourself to high amounts of hazardous chemicals.”

Previous research focused on plastic chemicals entering the body through food and drink. But this study highlights skin absorption as an additional contamination route. Once in the body, toxic substances accumulate. Scientists recently found flame retardants that the US phased out over a decade ago in all tested samples of breast milk. Experts think exposure to carcinogens through consumer products is driving rising cancer rates among young people.

Alden Wicker’s upcoming book explores the many ways clothing exposes us to industrial chemicals. She said activewear labeled sweat-wicking or water-repellent often contains highly persistent PFAS. And the dispersed dyes used on polyester are known to irritate skin.

The most hazardous ingredients remain untested. There are over 13,000 chemicals used in plastic products. Since brands rarely trace their entire supply chain, they don’t even know everything applied in the manufacturing process.

To avoid absorbing toxins through your skin, choose natural fabrics for workout clothes. Look for items made predominantly of organic cotton, hemp, or wool. Check labels for certifications by groups like GOTS that set health and environmental standards.

Switching completely to natural activewear may be costly. But gradually replacing synthetic pieces can reduce exposure, especially for those with chemical sensitivities.

While individual choices matter, systematic change is also needed. Experts say federal oversight and legislation are necessary to rid all consumer products of avoidable toxic chemicals.

Until then, your old yoga pants are likely exposing you to unnecessary health risks. Being aware of the problem is the first step toward safer, non-toxic workout wear.

Sweating in plastic-based fabrics allows chemicals to leach onto your skin. Repeated exposure over time leads to bioaccumulation in the body, which may contribute to adverse health effects. Polyester, Spandex, and other synthetics contain harmful additives like phthalates, bisphenols, and PFAS. These substances are associated with issues including hormonal disruption, thyroid disease, reproductive harm, and cancer.

Experts advise gradually switching to natural textiles for activewear. Federal action is also needed to regulate toxic chemicals in consumer products. While brands must list fabric contents, they are not required to disclose specific chemical ingredients used in manufacturing. More transparency and oversight is necessary to reduce needless exposures that disproportionately impact women and people of color.