Both the Fitbit Charge 4 and Samsung Galaxy Watch Active2 demonstrated acceptable heart rate measurement accuracy with an overall mean absolute percentage error of less than 10% across various activities.
Observational (n=23)
No
Do the Fitbit Charge 4 and Samsung Galaxy Watch Active2 accurately measure heart rate compared to a Holter ECG in healthy adults during various activities?
Both the Fitbit Charge 4 and Samsung Galaxy Watch Active2 provide valid heart rate measurements (MAPE <10%) across various activities, though accuracy varies by activity type and device.
BACKGROUND: Fitness trackers and smart watches are frequently used to collect data in longitudinal medical studies. They allow continuous recording in real-life settings, potentially revealing previously uncaptured variabilities of biophysiological parameters and diseases. Adequate device accuracy is a prerequisite for meaningful research. OBJECTIVE: This study aims to assess the heart rate recording accuracy in two previously unvalidated devices: Fitbit Charge 4 and Samsung Galaxy Watch Active2. METHODS: Participants performed a study protocol comprising 5 resting and sedentary, 2 low-intensity, and 3 high-intensity exercise phases, lasting an average of 19 minutes 27 seconds. Participants wore two wearables simultaneously during all activities: Fitbit Charge 4 and Samsung Galaxy Watch Active2. Reference heart rate data were recorded using a medically certified Holter electrocardiogram. The data of the reference and evaluated devices were synchronized and compared at 1-second intervals. The mean, mean absolute error, mean absolute percentage error, Lin concordance correlation coefficient, Pearson correlation coefficient, and Bland-Altman plots were analyzed. RESULTS: A total of 23 healthy adults (mean age 24.2, SD 4.6 years) participated in our study. Overall, and across all activities, the Fitbit Charge 4 slightly underestimated the heart rate, whereas the Samsung Galaxy Watch Active2 overestimated it (-1.66 beats per minute bpm/3.84 bpm). The Fitbit Charge 4 achieved a lower mean absolute error during resting and sedentary activities (seated rest: 7.8 vs 9.4; typing: 8.1 vs 11.6; laying down left: 7.2 vs 9.4; laying down back: 6.0 vs 8.6; and walking slowly: 6.8 vs 7.7 bpm), whereas the Samsung Galaxy Watch Active2 performed better during and after low- and high-intensity activities (standing up: 12.3 vs 9.0; walking fast: 6.1 vs 5.8; stairs: 8.8 vs 6.9; squats: 15.7 vs 6.1; resting: 9.6 vs 5.6 bpm). CONCLUSIONS: Device accuracy varied with activity. Overall, both devices achieved a mean absolute percentage error of just <10%. Thus, they were considered to produce valid results based on the limits established by previous work in the field. Neither device reached sufficient accuracy during seated rest or keyboard typing. Thus, both devices may be eligible for use in respective studies; however, researchers should consider their individual study requirements.
Nissen et al. (Tue,) conducted a observational in Healthy adults (n=23). Fitbit Charge 4 and Samsung Galaxy Watch Active2 vs. Mind Media NeXus-10 MKI (Holter ECG) was evaluated on Heart rate measurement accuracy (Mean Absolute Percentage Error). Both the Fitbit Charge 4 and Samsung Galaxy Watch Active2 demonstrated acceptable heart rate measurement accuracy with an overall mean absolute percentage error of less than 10% across various activities.