Heart Rate Variability Responses to Acute Stress as Indicators of Perceived Stress and Resilience

Abstract

Heart rate variability (HRV) is a non-invasive physiological indicator of autonomic nervous system activity and provides an objective means to assess psychological states such as perceived stress and resilience. This study investigated whether HRV can reflect individual tendencies in terms of perceived stress and resilience, as assessed by the Perceived Stress Scale (PSS), the Connor-Davidson Resilience Scale (CD-RISC), and their combined groups according to the Perceived Stress Scale (PSS), the Connor-Davidson Resilience Scale (CD-RISC), and their combined groups, and examined the autonomic mechanisms underlying these constructs. Ninety-two adults completed both questionnaires and participated in a stress-induction protocol based on the Trier Social Stress Test, consisting of pre-resting, stress session, and post-resting sessions. HRV features across time, frequency, and nonlinear domains were extracted from the resting, reactivity, and recovery phases, analyzed with linear mixed models, and applied in classification models using sequential forward selection and leave-one-subject-out cross-validation. The results showed that high PSS participants exhibited reduced parasympathetic activity primarily at rest, whereas high CD-RISC individuals demonstrated higher parasympathetic activity and autonomic balance across all phases, with greater stability under acute stress and faster recovery. The combined PSS-CD-RISC grouping revealed compounded autonomic dysfunction in the high-stress-low-resilience quadrant. Classification accuracies reached approximately 82% for PSS and CD-RISC separately and 87% when combined, with resilience-related models benefiting particularly from reactivity and recovery features in addition to resting indices. These findings demonstrate that HRV captures distinct autonomic processes underlying stress and resilience, indicating that the two constructions are not redundant but complementary. HRV thus holds promise as a supportive indicator in wearable systems for continuous monitoring and personalized intervention.