How accurate is the Fitbit Versa 4's heart rate monitoring

Issues with Heart Rate Accuracy

1. Lag in Detecting Rapid Heart Rate Changes: The Versa 4 often lags behind in detecting rapid heart rate changes during intense workouts. For example, during a short but intense workout on an indoor bike, the Versa 4 reported a significantly lower maximum heart rate compared to an Apple Watch and a chest strap[1]. This lag can lead to inaccurate readings, especially in interval training or high-intensity interval workouts.

2. Discrepancies Compared to Other Devices: When compared to other devices like the Apple Watch or Pixel Watch, the Versa 4 tends to report heart rates that are 10-15 bpm lower during workouts[2]. This discrepancy can be frustrating for users who rely on accurate heart rate data to manage their exercise intensity.

3. Movement Impact: Rapid arm movements, common in activities like cycling or running, can further exacerbate the inaccuracy of heart rate readings. This issue is less pronounced with devices like the Apple Watch, which seem less affected by arm movement[3].

4. Algorithm Differences: Fitbit attributes some of these discrepancies to differences in algorithms used for heart rate tracking compared to other brands like Apple[2]. However, this does not fully address the reliability concerns during high-intensity activities.

Performance in Different Activities

- Cycling and Running: The Versa 4 struggles more with heart rate accuracy during outdoor activities like cycling, where wrist movement is more pronounced. In such scenarios, it often detects heart rates that are too low compared to more accurate devices like ECG chest straps[7].

- Lower-Intensity Workouts: For activities like yoga or walking, the heart rate tracking is generally more reliable, though still not perfect[4].

Conclusion

While the Fitbit Versa 4 is a solid choice for basic fitness tracking and sleep monitoring, its heart rate accuracy during intense workouts is a significant drawback. Users who prioritize precise heart rate monitoring may find it less reliable compared to other smartwatches on the market. However, for those not heavily reliant on heart rate data during exercise, the Versa 4 still offers a comfortable design and robust battery life[5][8].