On 9to5Mac, Zac Hall breaks down how the new electrodes work in the Apple Watch Series 4 based on details published by Apple when it updated watchOS last week with the new ECG app. For now, the ECG app is only available in the US, but that doesn’t mean that others can’t benefit from the hardware that it uses. As Hall explains:
According to Apple, putting your finger on the Digital Crown to capture a heart rate reading also measures faster and with more accuracy as it updates every second versus every five seconds while the measurement is active.
That’s because placing your finger on the Digital Crown completes a circuit between your heart and arms that allows the Watch to record electrical impulses across your chest.
It will take time for the ECG app to gain the approval of regulators worldwide. However, in the meantime, it’s nice to know that the hardware that makes the ECG app possible is enhancing heart rate capture for everyone.