Sport and exercise make a significant contribution to physical well-being – but what if the clothes you wear make you sick?
The use of per- and polyfluorinated alkyl substances (PFAS) and PFC perfluorocarbons (PFC), better known as ‘forever chemicals’, has already been much discussed. They are used to coat textiles, but pose a risk to people and the environment. A new study shows that another group of chemicals commonly found in sportswear could be harmful.
Although stretch, breathability and sweat absorption are among the features consumers look for in activewear, less attention is paid to how the garments are made. Synthetic materials like spandex, polyester, and nylon, commonly used in sports bras and leggings, are essentially plastics made from petrochemicals.
However, to ensure these properties essential for sports, these materials often contain chemical additives, including phthalates and bisphenols, which can be extracted through sweat and absorbed through the skin. These chemicals, known as brominated flame retardants, are found in a variety of products to prevent ignition, for example. However, they are now being linked to health problems such as thyroid and hormonal disorders as well as neurological diseases.
According to the study ‘New insights into dermal bioaccessibility and human exposure to brominated flame retardants in microplastics’ published by the US Chemical Society, sweat containing oil promotes the leakage of chemicals from plastics due to its lipophilic properties. The body causes this process as soon as it comes into contact with the skin.
The more you sweat, the more chemicals your body could absorb
Researchers at the University of Birmingham in the UK conducted tests looking at flame retardants in textiles and the interaction between sweat and plastics during domestic activities. The scientists noted that further studies are needed to determine the specific chemicals and amounts absorbed during exertion through synthetic workout clothing. However, overall results suggest that the more the body sweats, the more chemicals it absorbs.
The study, published in July, also showed that other artificial additives such as bisphenols, phthalates and PFAS can leach into sweat and be absorbed through the skin. Bisphenols in particular were detected in some sports textiles in quantities that were up to 40 times higher than the safe limit. With repeated exposure, this process leads to increased levels of chemicals in the body and poses health risks.
Prior to this study, others had been conducted that highlighted the potentially harmful effects of skin-absorbed chemicals in sportswear. In the spring, studies by the US Center for Environmental Health found elevated levels of the harmful plastic compound BPA in sports bras and clothing from some brands, including sportswear companies Nike, Adidas, Patagonia and Athleta. These levels exceeded California’s stringent safety standards set by Proposition 65 labeling law by nearly 40 times.
While most studies on BPA focus on dietary intake, absorption through the skin in athletic clothing is a concern, particularly because of its association with asthma and cardiovascular disease. Continuous exposure to BPA from various sources is a growing health problem, even if the chemical only remains in the body for a short time.
Back in October 2022, the Center for Environmental Health warned consumers about excessive BPA levels in sports bras from brands such as Victoria’s Secret subsidiary Pink, Nike, Fila, The North Face and Asics, which exceeded the maximum level by more than that exceeded 22 times. Similar results were reported for sports shirts from Reebok, New Balance, The North Face and Mizuno. The organization gave companies 60 days to correct the grievances before taking legal action in February.
Avoiding the substances mentioned as well as BFR and PFAS, a group of over 4,700 man-made chemicals that are also used outside the fashion industry, remains a challenge. They continue to be used in various areas such as packaging, cookware and cosmetics. If you want to keep the possible effects of these substances to a minimum, you should choose sportswear made from organic, minimally treated natural fibers such as organic cotton, hemp or merino wool.
This article originally appeared on FashionUnited.nl. Translated and edited by Heide Halama.