How to Keep an eye on your heart
Get a reading
Get a heart rate reading by opening the Heart Rate app on your Watch, and letting it do its thing! Or, you can add a complication that includes the latest reading to some watch faces. (Watch Series 1 or later.)
On Watch Series 1 or later, go to the Watch app on your iPhone and tap Heart Rate. Here, tell your Watch to notify you if your heart rate goes above a certain level during a period of inactivity, which can be a bad sign.
The free Cardiogram app from the App Store can use your Watch’s heart rate data to give you useful info. Open the app on iPhone to see graphs of your activity, and see how your data compares to the average.