tech2 News StaffMay 04, 2015 11:00:03 IST
Update: Apple now acknowledges that tattoos could interfere with the working of the Apple watch. In a support page, the company writes, "Permanent or temporary changes to your skin, such as some tattoos, can also impact heart rate sensor performance. The ink, pattern, and saturation of some tattoos can block light from the sensor, making it difficult to get reliable readings. If you’re not able to get a consistent reading because of any of these factors, you can connect your Apple Watch wirelessly to external heart rate monitors such as Bluetooth chest straps."
Going by the chatter online, Apple Watch shows inaccurate heart rate results and loses connection when used on tattooed wrists.
Twitterati has already started calling it TattooGate.
If you remember, just a couple of days before the Apple Watch hit store shelves, Apple published a support page explaining how the wearable measures your heart rate. It explained a process called photoplethysmography that is used by the sensors. The blood absorbs red and reflects green light. So, the Watch uses green LED lights paired with light‑sensitive photodiodes that detects the amount of blood flowing through the wrist every time. “When your heart beats, the blood flow in your wrist — and the green light absorption — is greater. Between beats, it’s less. By flashing its LED lights hundreds of times per second, Apple Watch can calculate the number of times the heart beats each minute — your heart rate,” the page said.
This means, if there is anything reducing the reflectiveness of light, it will interfere with the sensor, eventually leading to inaccurate readings. However, it works fine with natural skin pigmentation.
iMore tested it with tattooed and non-tattooed wrist. "On non-tattooed non-wrist sections, the sensors gave identical readings as when also tested on the wrist; on tattooed sections, sensor readings varied wildly depending on colors and shading. Dark, solid colors seem to give the sensor the most trouble," the report adds.
Tattoos with lighter colours gave less trouble. This seem troublesome for those with tattooed wrists who have spent hefty sum on the device.
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