| Summary: | 碩士 === 大仁科技大學 === 環境管理研究所 === 103 === Low-frequency noise by generators, air conditioners, refrigerators, etc. is a common stressor in everyday life. In the low-frequency noise exposure environment we will have other health risks as much as hearing loss. The aim of this study was to investigate the influence of the human heart rate variability (HRV) in the low-frequency noise. Research on the health of the male participants solicited 24 people, aged 24.0 ± 5.8 years. Physiological signal for each participant was obtained from the AD Instruments PowerLab 26T with the LabChart 7 for Windows software. The evaluation intensities of low frequency noises (from 20 to 200 Hz) were background noise (BN), 70 dBC, 80 dBC, and 90 dBC. The electrocardiographic (ECG) data was recorded for 5 minutes under various noise levels. In the time domain, the results showed that mean beat-to-beat (RR) interval variability did not substantially change relative to the noise levels; in the frequency domain, three main spectral components by the fast Fourier transform method (FFT) are distinguished in a spectrum calculated from short-term HRV: very low-frequency (VLF, 0–0.04 Hz), LF (0.04–0.15 Hz), and HF (0.15–0.4 Hz) components. However, the low-frequency (LF) power and the ratio of LF power to high-frequency power (LF/HF) from ECG under the BN condition were significantly lower than the 80 dBC, and 90 dBC noise levels. It has been suggested that the frequency-domain-based measures appear to be a powerful tool for exposure to low-frequency noise. We concluded that exposure to low-frequency noise significantly affects the temporal correlations of HRV, but it does not influence RR intervals variability.
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