Use your Apple Watch to read your heart rate and monitor your performance during the live workout. It uses HealthKit to save and store your heart rate information.
Your pulse rate is used to help to guide your workout to reach your goals. The trainer can see your pulse to help motivate you to be in your zone. Your pulse is also in the leader board to make your workout fun. It lets you see how you are doing compared to other in the class. In addition to your pulse rate, it shows your percent of maximum recommended pulse rate for your age. The percent of max rate allows all ages to be ranked equally.

Heartrate app should not be used as a medical device. Consult your doctor or physician on your target and maximum heart rate prior to using this app. Let your trainer know your doctor’s guideline so they can help you stay within physician’s recommendation.