Did you know that Apple Watch can notify you if you’re having an abnormally high heart rate? This is a health feature that’s not enabled by default, but it’s pretty easy to set up and use. Apple Watch is a smartwatch that emphasizes on health features. With the internal sensors on your Apple Watch, it is able to keep a check on your heart beat and detect irregular rhythm that may be atrial fibrillation.
Link: How to Set Apple Watch to Notify High Heart Rate