What is ECG on a smartwatch and how does it work?

ECG stands for electrocardiogram — it's a reading of your heart's electrical activity. Your smartwatch takes a tiny snapshot of your heartbeat and checks if the rhythm is normal or if there's an irregular pattern. It's designed to catch problems like atrial fibrillation early, though it's not a replacement for a real medical examination.

Your smartwatch can take an ECG reading by measuring the tiny electrical signals your heart produces. When you place your finger on the watch and hold still for 30 seconds, it records a snapshot of your heart rhythm. If the reading looks normal, you'll get a reassuring notification. If the watch detects something unusual like an irregular heartbeat, it will alert you so you can follow up with a doctor.