Using heart rate to detect stressful moments in daily life is difficult, because physical activity and changes in posture also affect heart rate.
This study aimed to improve stress detection by adjusting heart rate for changes in posture, type of physical activity, and the prolonged impact of physical activity using accelerometer data. This is a concept called additional heart rate.
In laboratory experiments of 197 participants, we tested whether additional heart rate was able to distinguish between the effects of physical demands and mental demands on heart rate. Results showed that this method filtered out the effects of physical activity reasonably well. Additional heart rate was able to pick up individual differences in stress responses. However, additional heart rate was modestly useful in separating physical from mental stress within individuals, though it performed better than unadjusted heart rate.
The results should be interpreted in light of the laboratory setting. Additional heart rate relies on a correct estimation of baseline heart rate, which tends to be difficult to obtain in laboratory settings. Therefore, we suggest that the potential of this method in differentiating physical and mental demands on heart rate should be explored in participants’ daily life.
The study suggests that “additional heart rate” can improve stress detection by adjusting for physical activity and postural change. The laboratory experiment indicated the shortcoming that differentiating physical stress from mental stress remains challenging within individuals. Therefore, future research should validate this method in naturally occurring stressors in daily life.
Accelerometer-based heart rate adjustment for ambulatory stress research. van de Ven, S., Gevonden, M., Noordzij, M.N., & de Geus, E.J.C. Psychophysiology 2025 Jan;62(1):e14721.
