Autonomic stress response modes and ambulatory heart rate level and variability

The major goals of this study were (1) to determine consistency of autonomic response modes to different laboratory stressors, and (2) to evaluate the strength of the association between autonomic response modes and ambulatory heart rate and variability. The sample consisted of 45 healthy participants. Parasympathetic (PNS) and sympathetic (SNS) reactivity to and recovery from laboratory stressors (handgrip, logical-mathematical, mirror-tracing, and rumination tasks) were estimated by high frequency heart rate variability (HF-HRV), preejection period (PEP), and baroreflex sensitivity (BRS). Ambulatory HR was measured for 24 h on a work and a nonwork day, counterbalanced. As BRS was less reliable compared to PEP and HF-HRV, the latter two parameters were selected for the computation of SNS/PNS patterns. Autonomic modes were consistent across tasks and more stable during the recovery periods. Moreover, recovery appeared to be sensitive to the emotionality of tasks. Reactivity and recovery patterns differed as a function of gender, with women showing higher vagal tone at baseline, higher HR reactivity to the logical task, greater BRS decrease during the rumination task, and a larger decrease in vagal tone during recovery after the rumination task. After controlling for gender and baseline HR and variability, autonomic profiles during reactivity and recovery periods captured substantially different ambulatory information. Specifically, autonomic profiles during reactivity significantly predicted ambulatory HR level during waking hours, whereas autonomic profile during recovery was linked with ambulatory HRV. Coactivation of SNS and PNS activity was associated with the highest ambulatory HR levels and variability. Findings from the laboratory were consistent with a dimensional autonomic model viewing SNS and PNS contributions to heart rate on orthogonal axes and individual stress response stereotypy. Laboratory task-related autonomic reactivity and recovery may reflect parallel differences in HR level and variability in everyday life.