Tattooed Arms? Apple Watch Users Beware


If you have a tattooed wrist your ability to monitor your health may be in jeopardy according to apple watch users.    We caution those who may be interested in apple products. 



It may be impossible to get any heart rate reading at all -  says Apple that's if you have arms filled with tattoos.



If you need another reason to rethink getting that sleeve tattoo, Apple just gave you one: the Apple Watch doesn't work so well when worn on a tattooed wrist. A few days after the smartwatch's launch, users on Reddit, Twitter, and other social media channels are reporting that the Watch loses connection and reports inaccurate heart rate results when placed over tattoos. 
Such an issue could quickly prove annoying, since Apple Watch requests a security PIN almost immediately after it detects it has left an owner's wrist. Here, that's happening while it's still securely strapped on. iMore has already conducted some pretty thorough tests and found that yes, Apple's watch can run into significant problems on inked customers.
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.
Tattoos with lighter colors seemed to give Apple Watch less trouble, only leading to heart rate readings that were slightly off the mark. As for patterned tattoos, iMore's tests showed no errors, but this can obviously vary wildly depending on a specific tattoo design.

Apple warns of potential problems on its website, but doesn't specifically mention tattoos.


But when you consider how Apple Watch gets those heart rate readings, this problem shouldn't be very surprising. Here's how the company explains the technology:
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 approach is one shared by other fitness bands including Fitbit's Charge HR and the Microsoft Band. The ink from a tattoo can dramatically complicate things for these devices in ways that natural human skin pigmentation never would. On the same page where it offers technical details on the heart rate sensor, Apple also says, "For a small percentage of users, various factors may make it impossible to get any heart rate reading at all."