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Your Cute Wrist Tattoo Could Ruin Your Apple Watch Experience

A little ink can mess with the wearable's high-end tech.

Getting a tattoo is a big deal. Getting the Apple Watch is also a big deal. And now you may be forced to decide between getting one or the other.

Apple Watch users on Reddit and Twitter claim the device malfunctions when placed over tattoos. In particular, it's giving inaccurate heart rate results.

You may be thinking, ah I'm young, who needs the heart rate monitor anyway? But in addition to accurate workout readings, that sensor -- technically known as the photoplethysmograph -- also detects skin contact. When it detects that the connection with the wearer has been broken, the user will be prompted to enter the passcode. Every time.

The below video depicts some of these tattoo-related malfunctions, and it's easy to see how this could become a nuisance if it happens multiple times per day:

Of course, you could also lose contact with the watch from normal wear and activity, so to get a better idea of just how significant the tattoo issue is, iMore conducted some performance tests. The site concluded that "dark, solid colors seem to give the sensor the most trouble -- our tests on solid black and red initially produced heart rate misreadings of up to 196 BPM before failing to read skin contact entirely."

What's causing this malfunction? It actually makes sense after reading Apple's support page:

"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. When your heart beats, the blood flow in your wrist -- and the green light absorption -- is greater."

Dark tattoo ink interferes with this green light absorption so the LED lights can't accurately detect how much blood is flowing through your wrist. It's not a problem exclusive to the Apple Watch, either. Other fitness bands on the market use similar light-detection sensors.

Apple vaguely states on its support page that "For a small percentage of users, various factors may make it impossible to get any heart rate reading at all." iMore adds that natural skin pigmentation won't affect the light detection, but scar tissue could present the same problems as tattoos.

The good news for tatted-up technophiles who dropped a few hundred bucks on ink and at least another $350 on the Apple Watch is that there's a 14-day return policy. You can also disable the wrist detection feature, but then you'll have to say goodbye to Apple Pay and knowing your heart rate.