Background: The aim of this study was to assess heart rate variability (HRV) as a measure of cardiac autonomic status in psychiatric patients exposed to chemical irritants, comparing them to a healthy control group.Materials and Methods: A total of 100 participants, including 50 psychiatric patients exposed to chemical irritants (case group) and 50 age- and gender-matched healthy individuals (control group), were recruited. HRV was measured using a 24-hour ambulatory Holter monitor, and time-domain (SDNN, RMSSD, PNN50) and frequency-domain (LF, HF, LF/HF ratio) measures were analyzed. Demographic information, including chemical exposure history, was collected using structured questionnaires. Statistical analyses were performed using SPSS version 25.Results: Significant differences in HRV measures were found between the case and control groups. The case group had significantly lower SDNN, RMSSD, and PNN50 values (28.4 ± 7.5 ms, 20.1 ± 6.3 ms, and 16.7 ± 9.2%, respectively) compared to the control group (42.5 ± 10.2 ms, 33.5 ± 8.9 ms, and 22.8 ± 7.1%, respectively) (p < 0.001). Additionally, the case group exhibited lower LF and HF power and a higher LF/HF ratio, suggesting increased sympathetic dominance. Chemical exposure characteristics revealed that 30% of the case group were exposed to industrial chemicals, 44% to household cleaning products, and 20% to solvents. Significant negative correlations between HRV measures and chemical exposure duration were observed.Conclusion: This study highlights that psychiatric patients exposed to chemical irritants exhibit altered autonomic regulation, with reduced parasympathetic activity and increased sympathetic dominance. These findings suggest that prolonged chemical exposure may contribute to autonomic dysfunction and have important implications for cardiovascular health in psychiatric patients.