Have you got your wrist painted in dark-colored tattoos? Your peers, Facebook friends or Instagram followers drop plenty of likes and comments on the color, the message or the idea behind it, but Apple Watch just won’t support it! Recent updates released by the Cupertino-based tech giant cleared the clouds of doubt by confirming that tattoos might affect the accuracy of heart-rate readings and performance of the device. How? Why? Apple has a scientific explanation to support why Apple Watch will not work right on inky wearers.

First of all, how Apple Watch works and reads heart rate?

Apple Watch uses photoplethysmography technology as its heart rate sensor. Though it may sound a heavy scientific jargon, but this technology works really simple. Photoplethysmography in Apple Watch comprises green LED lights and light‑sensitive photodiodes. Both these elements monitor blood flow inside users’ wrists. The pace at which the device flashes light is 100 per second – the light absorption is greater during every heart beat and in between, absorption is low. That’s how Apple detects your heart rates.   

Why dark color will affect Apple Watch’s sensors?

In a report published by Apple reveal many factors which may affect the accuracy and performance of the Apple Watch sensors – dark skin color is reportedly one of them. Skin perfusion is the amount of blood flow through our skin and it largely varied impacted by the time of the day, weather and special health condition. In cold climate, users’ skin perfusion on their wrists will be too low to capture heart rate sensor reading. Moreover, movements such as brisk walk, jogging, running or cycling yield better heart readings when compared to activities such as boxing or tennis. Additionally, inked skin or permanent color changes done by tattoo will affect performance of heart sensor reading as those dark color blocks LED light emitted from the sensor. The saturation and pattern of the tattoo ink are to blame for act as obstructions for the light to enter and take the correct reading of the pulse.

So, will tattooed wrists be deprived of the finesse of Apple?

Luckily, there is a fix in which you can sidestep this skin color issue and get consistent and accurate heart sensor readings while exercising and physical activities. For this, you can simply fasten Apple Watch device to external heart rate monitors wirelessly (for example, Bluetooth chest straps). Once connected, the device will use the built-in GPS of iPhone to track distance you cover every time you move, walk or run each day.

Another alternative is turning off Wrist Detection option in Apple Watch iOS app. But, switching off this option might stop you from using Apple Pay from on the watch. Wrap the watch on other non-tattooed wrist to avoid this problem.

Another factor that may affect heart sensor reading is fitting.

If Apple Watch is not fit properly or loose, the LED sensor lights will not be able to track heart beat and show incorrect readings. Hence, you need to tighten the band and make sure, the device is snugly fitted to your wrist to get the right readings.