In 2024 , the number of global smartwatch users exceeded 454.69 million. Due to the extremely high number of users, and recent discoveries, the negative impacts of smartwatches on health have gradually become recognized by the public.
Fluoroelastomer is an excellent rubber with extremely high corrosion resistance, not even afraid of “sulfuric acid hands.” Therefore, fluoroelastomer is used in some mid-to-high-end watch bands, such as the $49 Apple Watch Light Blush Sport Band.
However, fluoroelastomer may release PFAS (per- and polyfluoroalkyl substances), and then the PFAS is absorbed by the skin, causing some problems. In recent years, increasing evidence suggests that PFAS has many toxic effects on the human body. (The toxic emulsifier PFOA contained in some non-stick pans, as well as the contaminant PFOS in drinking water, both belong to PFAS)
A study found that 15 out of 22 common brands of smartwatch bands release PFAS. To reduce the body’s exposure to PFAS substances, changing to a band other than fluoroelastomer may be a good idea. It’s just that the effect is unknown, because PFAS is too common.
The reason why there are no relevant regulations to limit it is because the main PFAS substance released by fluoroelastomer bands is PFHxA, and there is currently little understanding of this substance. Because PFHxA is added as a substitute for PFOA, it is a substance required to manufacture fluoroelastomer. So, maybe it will be like some artificial sweeteners, and its harm will be discovered in the future.
Postscript: Wearing a smartwatch for a long time may cause skin folds under the watch face. Since smartwatches use flashing green light to measure heart rate, and red and infrared light to measure blood oxygen saturation, some people worry about whether the watch will cause abnormal skin aging. But in reality, there is nothing wrong, it is just moisture accumulation under the skin, the skin is “puffed up,” just switch hands or rest for a while.