Effects of low-frequency noise from wind turbines on heart rate variability in healthy individuals

Abstract Background: Wind power has been applied around the world as a source of clean energy. However, wind turbines generate low-frequency noise (LFN, 20-200 Hz), which poses health risks to nearby residents. This study aimed to assess heart rate variability (HRV) response to LFN exposure and to evaluate the LFN exposure (dB, LAeq) inside households located near wind turbines. Methods: Thirty subjects living within a 500 m radius of wind turbines were recruited. The field campaigns for LFN (LAeq) and HRV monitoring were carried out in July and December 2018. A generalized additive mixed model was employed to evaluate the relationship between HRV changes and LFN. Results: The results suggested that the standard deviations of all normal to normal R-R intervals reduced significantly by 3.39% with a 95% CI = (0.15%, 6.52%) per 7.86 dB (LAeq) of LFN in the exposure range of 38.2-57.1 dB (LAeq)—i.e., a 0.43% reduction per 1 dB (LAeq). The results of household monitoring showed that the indoor LFN exposure (LAeq) ranged between 30.7 and 43.4 dB (LAeq) at a distance of 124-330 m from wind turbines. The worst case had 99.6%, 89.1%, and 96.8% at daytime, evening, and nighttime, respectively, exceeding the LFN standards of the Taiwan Environmental Protection Administration. Moreover, households built with concrete and equipped with airtight windows showed the highest LFN difference of 13.7 dB between indoors and outdoors. Conclusion: This work is the first study assessing the HRV impacts from turbine LFN in Asia, where wind turbines installed within short distances from residential areas. In view of the adverse health impacts of LFN exposure, there should be regulations on the requisite distances of wind turbines from residential communities for health protection.