How to measure heart rate on your smartwatch
Modern smartwatches have a wide array of heart-rate monitoring features. That includes passive all-day monitoring as well as spot checks for specific metrics. Some will even alert you if your heart rate suddenly spikes when it shouldn’t. The most advanced devices also have FDA-cleared electrocardiograms that may help detect atrial fibrillation.
These are impressive features considering that, just a decade ago, smartwatches were basically pedometers. In practice, heart rate monitoring can be a helpful tool for people hoping to understand more about their bodies or measure their fitness progress over time. For instance, some athletes prefer to train in heart rate zones — which is hard to do unless you can check it in real time. There have...