October 16, 2026 · 10 MIN
Heart Rate Monitor Accuracy: Chest Strap vs Optical Wrist Sensor
Heart rate monitor accuracy matters more than most athletes realise — a 10 bpm error on a threshold interval can place you in the wrong training zone entirely, undermining months of structured work. ECG-based chest straps and PPG optical wrist sensors operate on fundamentally different principles, with very different accuracy profiles across conditions. Here is what the research says about which technology to trust, and when.
