Dynamic Salivary L-Histidine Responses to High-Intensity Physiological Stress and Psychometric Correlations

Abstract:
Purpose: L-Histidine, the histamine precursor, shows stress-responsive potential but its salivary dynamics remain unclear. This study explored salivary histidine (s-His) changes under different stress and correlations with psychological traits. Methods: Thirty healthy male college students participated in 8-kilometer running and emotional picture viewing tasks to induce physiological and psychological stress, respectively. S-His levels were dynamically monitored. Participants were divided into healthy control (HC) and psychological subhealth (PS) groups based on psychometric scale results. Results: Key findings include: (1) S-His significantly increased in response to physical stress and returned to baseline within 30 minutes post-exercise, indicating a sensitive and reversible stress response. (2) Baseline s-His negatively correlated with Phobic Anxiety (R = -0.667, P = 0.025) and Yang-deficient constitution (R = -0.690, P = 0.019) in HC, while post-exercise levels linked to Agreeableness (R = 0.759, P = 0.004). (3) In PS individuals, Deltas-His (post-exercise minus pre-exercise) exhibited strong positive correlations with Psychoticism and Hostility (R = 0.954-0.873, P < 0.01), forming a "high Deltas-His—high psychopathology risk" pattern. Conclusion: Findings suggest s-his shows a sensitive response to physiological stress and correlates significantly with psychological traits, suggesting its potential as a new non-invasive biomarker for assessing stress and mental health.