BUG: Heart Rate Errors in Workout Mode - Bugs and Support - Zwift Forums
K2pi - K2pi/K2pi+ and Polar Heart rate monitor H10. (How to use H10 with other apps Peloton/zwift in conjunction with K2pi converter) Polar H10 is the only compatible HR sensor that works
A Look at Polar's New Heart Rate Broadcasting for Apps like Zwift and Peloton | DC Rainmaker