Apple Watch Might Spazz Out If Your Wrist Is Covered In Dark Tattoos

There's nothing quite like sinking $17,000 into a fancy Apple Watch with 18-karat gold only to find out that your sweet as hell sleeve tattoo is preventing it from functioning the way it's supposed to. Same goes for the $349 Apple Watch Sport models for the somewhat wiser among us who aren't willing to pay nearly the equivalent of a Honda Civic for a piece of jewelry that's likely 6-12 months from being a generation behind the technology curve. But that's a topic for another day, let's get back to what's already being called tattoogate (*groan*).

That colorful sleeve tattoo you're sporting might be a true work of art, but the ink pigmentation has a tendency to flummox the Apple Watch's heart rate sensor. There are several reports of this happening scattered around the web, and also a YouTube video that compares the functionality of an Apple Watch on a wrist with no tattoo to one that has a sleeve tattoo.

Apple Watch and Tattoo

Why is this happening?

"Blood is red because it reflects red light and absorbs green light. Apple Watch uses green LED lights paired with light‑sensitive photodiodes to detect the amount of blood flowing through your wrist at any given moment," Apple states in a support document. "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."

This is where the pigmentation in tattoos can interfere with Apple Watch from doing its thing. According to Apple, the heart rate sensor also uses infrared light, but if the reading isn't adequate enough, it switches to the aforementioned green LEDs.

This isn't a problem for all tattoos, nor does natural skim pigmentation affect the Apple Watch. Where you're most likely to run into an issue is when wearing an Apple Watch on top of a dark, solid colored tattoo. According to tests conducted by iMore, solid black and red posed the most problems, whereas tests on lighter tattoo colors (purple, yellow, and orange) were less problematic, though still produced slightly elevated heartbeat readings.

Bottom line? If you have a tattoo on your wrist/arm and decide to buy an Apple Watch, give it a thorough testing -- there's a 14-day return policy.