Apple has come out and confirmed that the Apple Watch will have problems in tracking heart rates for those who have tattoos on their wrist.
The issue will not only affect the device's ability to track heart rates but will also affect the device's ability to automatically unlock when it detects that it is being worn by the user.
"Permanent or temporary changes to your skin, such as some tattoos, can also impact heart rate sensor performance. The ink, pattern, and saturation of some tattoos can block light from the sensor, making it difficult to get reliable readings," says the company on its Apple Watch support page. "If you're not able to get a consistent reading because of any of these factors, you can connect your Apple Watch wirelessly to external heart rate monitors such as Bluetooth chest straps."
This is the first time that the company itself has acknowledged the issues that might come with tattoos and the watch. Unfortunately for many, it is a little too late for some users who have tattoos but have already purchased the device.
The reason that it is an issue lies in how the watch detects heart rate. The Apple Watch essentially uses LED lights. When that light hits blood, red light is reflected, while green light is absorbed. It makes sense, because of this, that with different colored tattoos, different light is reflected.
"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," said Apple. "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."
Of course, the problem is not limited to the Apple Watch, but rather to any device that uses light to try and detect heart rate.
Of course, the issue could unfortunately also affect those with darker skin, as darker skin also reflects back different colors of light than those with lighter skin.
Apple was also quick to remind users that they can use heart rate monitoring devices from other companies, which will then connect to the device via Bluetooth.
It is expected that Apple might work on ways to change the technology for future versions of the Apple Watch so that more people will be able to use it.