Cold induced pain elicits reproducible breath metabolomic responses across geographically distinct populations

= 21 in China) underwent four breath measurements: two pre- and two post-CPT intervention. Mass spectral data revealed a reproducible and rapid metabolic shift, with over 400 upregulated features consistently observed across both cohorts. Pathway enrichment and correlation analyses implicated amino acid metabolism (e.g., glutamate, arginine, and threonine) and stress-related pathways (e.g., creatine, butanoate, and citric acid cycle intermediates). A neural network classifier distinguished pre-vs. post-CPT states (AUC = 0.856, 78% accuracy). Our findings support real-time breath analysis as a non-invasive method for detecting short-term physiological responses.