HeartStep allows people to get a health assessment previously only possible at their doctor's office. In this initial release for Apple Watch owners, the app allows users to self-conduct a step test (also known as a stress test) using their iOS phone. .Take the test and receive reports that rate your overall heart health against the rest of the population as well as other key data points.This app uses HealthKit to read data(Heart Rate & Resting Heart Rate) from Apple Watch.