An Evaluation of the Quantitative Relationship between the Subjective Stress Value and Heart Rate Variability

Abstract

We evaluated the quantitative relationship between the subjective stress value and heart rate\rvariability. The mean values of R-R interval (RRI) and respiratory sinus arrhythmia (RSA), which\rwere reported to be markedly affected by stress, were used as heart rate variability. The following\rmental workload was performed so as to give wide range loads to the subjects: presentation of\rresearch, asking questions in research presentation, research presentation practice, and supine rest.\rThe subjective stress value was obtained as serial values from 1 to 5 by a newly-developed\rquestionnaire. The correlation between the stress value and RRI or RSA when such wide range\rworkload are given was evaluated. There was a high correlation between the subjective stress value\rand RRI (correlation coefficient, -0.637), but not between the subjective stress value and RSA\r(coefficient, -0.319) Signal processing of RRI was simpler than that of RSA. These results suggest the\rusefulness of RRI as an index of the subjective stress value.