I’ve observed repeated false maximum heart rate detections on my Forerunner 970, even when paired with an HRM-600 chest strap. These spikes often exceed my normal well-rested race max HR (~170–172 bpm at age 61) by 30–40 bpm, briefly showing 200+ bpm before returning to normal. The device accepts these anomalies as valid, instantly raising my Max HR setting and shifting all training zones. This causes underestimation of activity intensity, inaccurate load/recovery guidance, and distorted VO₂max trends.
Recommendation: Please implement a “sanity check” filter before updating Max HR:
- Ignore values >10% above rolling historical max unless sustained ≥30 seconds
- Cross-verify spikes between optical and chest strap data
- Provide a user prompt to accept/reject new Max HR
This would prevent single-reading artifacts from corrupting long-term training data. I can provide FIT files showing the spikes if needed
