Validation of the Fitbit Charge 5 for the Detection of Heart Rate and Electrodermal Activity

Wearable devices are increasingly used to evaluate psychophysiological markers of anxiety for continuous health monitoring. Consumer-grade wearable devices, such as Fitbits, have the potential for widespread use and dissemination given their affordability and accessibility for both research and clinical settings. However, the validation of consumer-grade devices against research-grade devices is required. This study aimed to evaluate and compare the accuracy of the Fitbit Charge 5 against a research-grade wearable device, the Equivital EQ02, in measuring psychophysiological parameters of anxiety, specifically heart rate (HR) and electrodermal activity (EDA). Fifty-five undergraduate students (M_age = 19.4, SD_age = 1.6, 46% female) wore both Fitbit and Equivital devices whilst completing social stressor and reading tasks. Statistical analyses demonstrated significant moderate correlations between the two devices for heart rate (HR) estimates (rs = 0.45-0.58) and low to moderate correlations for electrodermal activity (EDA) estimates (rs = 0.42-0.50). Intraclass correlations were moderate for both HR (ICCs = 0.53-0.72) and EDA (ICCs = 0.46-0.64) across conditions (ps < 0.05). Furthermore, Bland-Altman analyses revealed that the Fitbit showed a pattern of underestimation of HR (ranging from 24 to 32 bpm) and overestimation of EDA (ranging from -12.92 to 10.29 μS) compared to the Equivital. These findings highlight potential reliability concerns with the Fitbit Charge 5 in measuring physiological data. While the device may have some utility in assessing HR and EDA, it is crucial to approach the interpretation of data from consumer-grade wearable devices with caution due to potential accuracy limitations.