Smartwatches and Fitness Trackers Contain Forever Chemicals

Roughly a quarter of people worldwide, and 15 percent of Americans, use a smartwatch or fitness tracker, according to Demandsage, and those numbers are expected to keep growing. Not only can these devices give you fitness stats like your step count and calories burned, but they can monitor your heart rate if you’re at risk for cardiovascular disease, keep tabs on your sleep habits, and even track fertility in women. Despite all these wellness benefits, though, new research shows that these wearable devices may actually be harming your health with their “very high concentrations” of forever chemicals.

RELATED: Your Nail Polish and Perfume Could Harm Your Heart and Brain Health, Research Warns.

What are forever chemicals?

Forever chemicals are formally known as per- and polyfluoroalkyl substances (PFAS). These manufactured chemicals are concerning because “many break down very slowly and can build up in people, animals, and the environment over time,” explains the U.S. Environmental Protection Agency (EPA). They can be found in drinking water, personal care products, cleaning products, nonstick cookware, electronics, food packaging, and more.

Though researchers are still working to better understand how PFAS harm human health, the EPA notes that scientific studies support the following detrimental effects:

Fertility issues

Hormonal imbalances

Developmental issues in children

Increased risk of certain cancers

Decreased immunity

Increased cholesterol levels

“Once all these health studies started to come to light, independent scientists started doing more and more work on the effects of PFAS,” said Stanford Medicine’s Lisa Patel, MD, a clinical associate professor of pediatrics, who is on the executive committee for the American Academy of Pediatrics Council on Environmental Health and Climate Change, in an interview for the school’s blog Scope. “Each new study that comes out concerns us more, not just because of what the health effects of these chemicals are, but because of how hard it is to get rid of them once they’re out there.”

New research found elevated levels of PFAS in some fitness trackers and smartwatches.

A new study published in the journal Environmental Science & Technology Letters tested 22 fitness tracker and smartwatch wristbands sold in the U.S. and found that nine contained elevated levels of a type of PFAS called perfluorohexanoic acid (PFHxA).

“This discovery stands out because of the very high concentrations of one type of forever chemical found in items that are in prolonged contact with our skin,” says Graham Peaslee, the co-author of the study and professor emeritus in the Department of Physics and Astronomy at the University of Notre, in a press release.

It’s important to note that the study did not disclose the specific brands or styles of the tested devices.

PFHxA was the most concerning forever chemical in the wristbands.

The study looked at wristbands made of fluoroelastomers, “a synthetic polymer used to make rubber material resistant to sweat, skin oils and lotions,” explains another press release. Of the 22 tested bands, 13 were advertised as being made of fluoroelastomers, meaning they contain the element flourine. However, two of the remaining nine brands also contained fluoroelastomers.

Previous research has classified fluoropolymers as a PFAS and recommended that “their production and uses should be curtailed except in cases of essential uses.”

However, the current study authors were most concerned by the presence of PFHxA, which was found in nine wristbands at a median concentration of nearly 800 parts per billion (ppb). One sample exceeded 16,000 ppb.

To put this in perspective, the press release notes that the same research team completed a study on cosmetics in 2023 and found a median PFAS concentration of roughly 200 ppb.

“We have never seen extractable concentrations in the part-per-million range (>1000 ppb) for any wearable consumer product applied to the skin,” said Peaslee.

Pricier devices contained more PFAS.

Of note, smartwatches and fitness trackers priced at $15 or higher had more PFHxA, while those that cost more than $30 had higher levels of fluorine.

While the study authors don’t surmise as to why this is, it would make sense to assume that pricier devices use more of these chemicals to achieve a sweat-proof design.

Alyssa Wicks, a graduate student in Peaslee’s lab and lead author of the study, suggests looking for cheaper devices made of silicone. “If the consumer wishes to purchase a higher-priced band, we suggest that they read the product descriptions and avoid any that are listed as containing fluoroelastomers,” she notes.

Should you be concerned about your smartwatch?

The researchers point out that more research is needed into how forever chemicals interact with our skin, especially for prolonged periods of time.

“Few studies so far have been published regarding the dermal absorption of PFAS,” said Wicks. “One article published earlier this year by a European research group found that a couple types of PFAS had significant transfer through the skin. That initial study only examined around 20 of the 14,000 known types of PFAS, and more studies are needed to better understand how PFAS travel through the skin.”

For now, follow Wicks’ advice and read the product descriptions of your smartwatch or band and swap it for an alternative if it’s listed as containing fluoroelastomers.

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