Heart Rate Variability Analysis in Workers Exposed to Methyl Bromide as a Quarantine Treatment.

OBJECTIVE:To determine whether methyl bromide (MB) fumigation work for plants imported in Korea affects workers' health by assessing heart rate variability (HRV). METHODS:We measured HRV indices (TP, VLF, LF, HF, HR, SDNN, pNN50 and HRV-index) and urinary bromide ion (Br-) in 62 fumigators (study group) and 34 inspectors (the control group) before and after fumigation work. In addition, the relationship between Br- concentration and HRV indices was analysed. RESULTS:The fumigators' post-work HRV indices and Br- level were changed compared with their pre-work values (P < 0.001). Conversely, inspectors' values were not shown a difference before and after work. The HRV indices in all subjects were negatively correlated with the Br- levels (P < 0.05). CONCLUSIONS:Fumigators with high Br- concentrations and low post-work HRV indices following MB fumigation work experienced adverse effects on their autonomic nervous systems.