If you're considering getting a sleeve tattoo and buying an Apple Watch at the same time (what are the odds?), here's a reason to think again. Users from Reddit, Twitter and other social media sites are reporting that, when worn over a tattoo, the Watch loses connection and the ability to read heart rate properly.
The smartwatch requests your security pin every time it detects itself leaving your wrists, so this issue can be very annoying. Imagine having to key in your pin every single time. Even iMore, a weblog for all things Apple, confirms the problem inked wrists present.
According to iMore, lighter coloured tattoos seem to give the fewest problems, only having trouble reading a proper heart rate, while patterned tattoos showed no error - but this may vary from user to user.
There's a very good explanation to why this is happening. Apple states:
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. 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 issue is shared among several other fitness bands including the Fitbit’s Charge HR and the Microsoft band but there is a solution - or rather a workaround - to the problem. Since Apple Watch is compatible with some popular Bluetooth heart rate chest straps such as the Polar H7, you could instead use those. Or wait for a software update that'll hopefully provide a proper fix.
[Source: The Verge]