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Background: Both exaggerated and diminished reactivity to stress can be maladaptive. Previous studies have shown that performing increasingly difficult tasks leads first to increased reactivity and then to a blunted response when success is impossible. Our aim was to investigate the influence of trait anxiety on cardiac and cortisol response to and recovery from a standardized psychosocial stress task (Trier Social Stress Task) in a homogeneous sample of healthy peacekeepers. We hypothesized that participants with higher trait anxiety would show blunted reactivity during the performance of an overwhelmingly difficult and stressful task. Participants (N = 50) delivered a speech and performed an arithmetic task in the presence of critical evaluators. Cortisol samples and electrocardiogram data were collected. Participants completed the State-Trait Anxiety Inventory-Trait version, the Posttraumatic Stress Disorder Checklist-Civilian Version (PCL-C) and the Military Peace Force Stressor Inventory. Results: For heart rate, the findings showed that peacekeepers with higher trait anxiety reacted less to the speech task (p = 0.03) and to the arithmetic task (p = 0.008) than those with lower trait anxiety. Trait anxiety did not modulate cortisol responses to the task. Despite the high trait anxiety group having higher PCL-C scores than the low trait anxiety group (p < 0.0001), this did not influence the cardiac results. Conclusions: We concluded that individuals with higher trait anxiety had less tachycardia in response to acute psychological stress than those with lower trait anxiety. The present results point to a higher risk for more anxious individuals of a maladaptive reaction to stressful events.
Souza, G. G. L., Mendonça-de-Souza, A. C. F., Duarte, A. F. A., Fischer, N. L., Souza, W. F., Coutinho, E., … Volchan, E. (2015). Blunted cardiac reactivity to psychological stress associated with higher trait anxiety: A study in peacekeepers. BMC Neuroscience, 16(1). https://doi.org/10.1186/s12868-015-0216-9