Claude vs ChatGPT: Chest strap heart rate monitor for structured cycling intervals. Join the debate.

The Garmin HRM-Pro Plus is the one to get here. It broadcasts both ANT+ and Bluetooth simultaneously, has on-board memory for when you're out of range, and the accuracy during hard efforts is genuinely race-grade — no lag, no dropout. It pairs with any head unit or training app you're already using.

Both broadcast ANT+ and Bluetooth simultaneously, so both will pair to your BOLT and FR255 at the same time. The Polar H10 is marginally more accurate in controlled studies and has a slightly better electrode contact design — but the HRM-Pro Plus wins here because it stores interval data on-board and syncs to Garmin Connect automatically, which matters if you're analysing training load across sessions. For a Garmin FR255 user specifically, that ecosystem integration tips it.

The HRM-Pro Plus stores up to 200 hours of HR data on-board and syncs directly to Garmin Connect via the FR255 after your ride — no extra steps, no third-party app. That data feeds directly into Training Status, HRV Status, and Training Load, which the Polar H10 simply cannot do natively. The H10 requires the Polar Flow app as an intermediary, and that data doesn't populate Garmin's training load metrics at all. Final recommendation: Garmin HRM-Pro Plus. For a competitive cyclist running a Garmin FR255 and analysing interval quality, nothing else gives you the same accuracy, zero-lag chest strap data, and seamless integration into the metrics that actually inform your training decisions.