A pilot study investigating heart rate variability as a measure of stress in healthy school children responding to experimental stressors

The body's response to stress, both in the short-term and long-term, is a key early indicator of potential psychological disturbances. Heart rate variability (HRV) is increasingly being utilised as a marker for physiological resilience. A pilot study involving a cross-sectional convenience sample of healthy 9- to 11-year-old schoolchildren (n=66) from East Anglia found that a physiological stressor triggered a stronger parasympathetic response (M = 16.41, SD = 29.4) compared to a social stressor (M = 5.33, SD = 32.96) p < .001. Furthermore, the children exhibited a greater parasympathetic response post stressor when following a breathing pacer (RSA) than when resting. The study also suggested a potential link between traumatic life events, as identified by a screening tool, and increased physiological resilience, indicated by higher HRV. However, this finding was not replicated when the event was validated using a more clinically established measure, possibly due to the limited sample size. In this study, self-reported resilience did not appear to correlate with physiological resilience. The pilot study provided valuable insights into the methods used and revealed ways to refine them as the project advanced. This process enabled observations and assessments of the impact of these adjustments, leading to a better understanding of which approaches would be most effective for optimizing the design of a larger-scale school-based study in the future. The study also underscored the challenges of working within a multi-faceted project team and engaging with school children in a school setting. The concepts of stress, resilience, HRV, and trauma are broad and complex, remaining essential areas for future research. This study explored some of this complexity, emphasizing the need for careful interpretation of conclusions. Nonetheless, the findings add to the growing body of literature that will help shape future policy, clinical interventions, school services, and healthcare systems.