Accelerometer‐based heart rate adjustment for ambulatory stress research

• Published in: Psychophysiology Vol. 62; no. 1; pp. e14721 - n/a
• Main Authors: Ven, Sjors R. B., Gevonden, Martin J., Noordzij, Matthijs L., Geus, Eco J. C.
• Format: Journal Article
• Language: English
• Published: United States Blackwell Publishing Ltd 01.01.2025; John Wiley and Sons Inc
• Subjects: accelerometer; Accelerometry - methods; additional heart rate; Adult; ambulatory assessment; autonomic nervous system; Exercise - physiology; Female; Heart rate; Heart Rate - physiology; Humans; Male; Original; Physical activity; Posture; Posture - physiology; Social interactions; stress; Stress response; Stress, Psychological - diagnosis; Stress, Psychological - physiopathology; Young Adult; additional heart rate; stress; heart rate; autonomic nervous system; ambulatory assessment; accelerometer
• ISSN: 0048-5772; 1469-8986; 1469-8986; 1540-5958
• DOI: 10.1111/psyp.14721

Using heart rate (HR) measurements to detect mental stress in naturalistic settings is hampered by the physiological impact of hemodynamic and metabolic demands. Correcting HR for these demands can help isolate fluctuations in HR associated with psychosocial stress responses, a concept termed additional heart rate (aHR). This study examined whether adding predictors for posture, activity type, and lagged movement intensity for the prolonged impact of physical activity (PA) improved aHR estimation across various manipulations of mental stress, posture, and PA in a controlled laboratory environment (n = 197). Accelerometer signals were used to obtain the movement intensity and to classify posture and activity type. Posture, activity type, and lagged movement intensity each led to a significant improvement in HR estimation, as measured by adjusted R2 and root mean squared error. However, HR was overestimated during quiet sitting. The aHR, computed as the difference between observed and predicted HR, generally underestimated observed task‐baseline reactivity but was sensitive to individual differences in reactivity to mental stressors. Between‐subject correlations of aHR with task‐baseline reactivity ranged from 0.62 to 0.93 across conditions. On a within‐subject level, the ability of aHR to differentiate between exposure to physical stress and mental stress was limited (recall = 0.32, precision = 0.31), but better than that of observed HR (recall = 0.02, precision = 0.02). Future research should explore the potential of this novel aHR estimation method in differentiating physical and mental demands on HR in daily life, and its predictive value for health outcomes. Conventional accelerometer‐based additional heart rate focuses solely on concurrent movement intensity to predict heart rate. This study introduces a novel method to correct heart rate not only for ongoing physical activity but also for postural changes, type of physical activity, and past physical activity. This approach enhances the ability to differentiate between the impact of physical and mental demands on heart rate in daily life.