The Ride App supports using either the integrated wrist based HR sensor on the Apple Watch, or connecting to an external HR sensor, such as a Viiiiiva.
To configure the HR source, go to Settings > HR > Choose HR Sensor
You will then have the option to choose which HR source is connected to the app.
- No HR - does not track heart rate
- Watch - uses the Apple Watch optical heart rate sensor
- HR Monitor - allows you to connect to 3rd party heart rate monitor, such as a Viiiiva.