I wanted to share my experience with the CMF Watch Pro 2, specifically regarding its fitness tracking. While I love the design and the UI, the heart rate (HR) sensor is proving to be incredibly unreliable during high-intensity training.
The Issue: Massive HR Lag & Under-reading
Lately, I’ve noticed that during very intense sessions where I’m clearly pushing my limits, the watch refuses to leave the 100–110 BPM range. To test this, I wore a dedicated pulse oximeter simultaneously, and the discrepancy was shocking:
Pulse Oximeter: 135–140 BPM (Accurate to my physical exertion)
CMF Watch Pro 2: ~100 BPM
Ripple Effect on Stats
Because the heart rate is reading so much lower than reality, it’s completely breaking the rest of the health metrics. Even after a grueling 30-minute workout that leaves me exhausted, the watch only credits me with 2 to 5 minutes of “Exercise Time.” It seems the algorithm only counts minutes as “exercise” if the HR hits a certain threshold, which the sensor is failing to detect. This leads to:
Inaccurate calorie burn estimates.
Incorrect recovery time suggestions.
Frustratingly empty activity rings/goals.
See the photo attached that shows huge discrepancy. Nothing needs to fix this
