When you wear your Apple Watch, a sensor on the back measures your heart rate. You can see your heart rate on your Apple Watch in the Heart Rate Glance or in the Workout app. Use the steps below to measure your heart rate.
Check the Heart Rate Glance

Wake your watch and swipe up on the watch face to open Glances. Then swipe left or right to find the Heart Rate Glance.
Track your heart rate while you work out

Open the Workout app and tap an activity to get started. Then swipe left or right to see your heart rate.
In addition, Apple Watch measures your heart rate throughout the day when you’re still. You can see these background heart rate measurements in the Health app on your iPhone. Since Apple Watch only takes this background reading when you're still, the time between these measurements will vary. You can control which third-party apps have access to your health data from the Health app in Sources.

Get the best measurement
Here are some tips for getting the best heart rate reading. You also want to make sure that your Apple Watch fits properly. It should lie flat on the top of your wrist so that the sensors make contact with the skin.