Adverse effect of noise on heart rate variability of occupationally exposed workers

Objective  To explore the adverse effect of noise on heart rate variability(HRV) of occupationally exposed workers.

Methods Totally 96 workers occupationally exposed to noise and 95 workers without noise exposure(control group) were studied. SDNN, RMSSD, PNN50, HF, LF, VLF and average heart rate in whole 24 hours(HR) were determined by 24 h ambulatory electrocardiograph(Holter). The value of these indexes was compared between two groups, and the correlation of HRV with age, employment time, gender and HR was analyzed.

Results  The levels of SDNN, PNN50, LF, VLF of workers in exposed group were significantly lower than those in the control group, while HR was significantly higher than that in the control group(P < 0.05).It showed that SDNN, PNN50, LF and VLF were negatively correlated with employment time and HR among exposed workers(r=-0.582--0.283, P < 0.05). The age could affect the SDNN, PNN50 and LF(r=-0.233--0.211, P < 0.05), while there was no difference of SDNN, PNN50, LF and VLF between male and female workers(P>0.05).

Conclusion HRV of noise-exposed workers appears blunted significantly, which suggests that long-term exposure to noise may result in impairment of cardiac autonomic nerve's activity.