The most advanced Apple Watch app, Selfloops Spark
Spark is the only application for Apple Watch that supports the Group Fitness heart rate tracking service with users having to wear just the Apple Watch to join a class (no need for additional accessories or heart rate monitors.)
The Selfloops Spark Apple Watch app can connect to rowers, treadmills and bikes using the FTMS Bluetooth protocol. It is the only app that can do this tracking.
You can also stream your heart rate data over the Internet with our Selfloops Streams service for live classes using your Apple Watch.