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

Abstract: 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) responses to LFN exposure and to evaluate the LFN exposure (dB, (LAeq) inside households located near wind turbines. 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. The results suggested that the standard deviations of all the normal to normal R–R intervals were 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). The indoor LFN exposure (LAeq) ranged between 30.7 and 43.4 dB (LAeq) at a distance of 124–330 m from wind turbines. Moreover, households built with concrete and equipped with airtight windows showed the highest LFN difference of 13.7 dB between indoors and outdoors. 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.

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LFN exposure has been found to cause a variety of health conditions. Exposure to LFN from wind turbines results in headaches, difficulty concentrating, irritability, fatigue, dizziness, tinnitus, aural pain sleep disturbances, and annoyance. Clinically, exposure to LFN from wind turbines may cause increased risk of epilepsy, cardiovascular effects, and coronary artery disease. It was also found that exposure to noise (including LFN) may have an impact on heart rate variability (HRV). HRV is the variation over time of the period between adjacent heartbeats, which is an indicator of the activities of the autonomic nervous system, consisting of the sympathetic nervous system (SNS) and parasympathetic nervous system (PNS). Autonomic imbalance usually represents a hyperactive SNS and a hypoactive PNS and results in reduced HRV. An autonomic imbalance may increase the morbidity and mortality of cardiovascular diseases. A review paper indicated that road traffic noise may overactivate the hypothalamic-pituitary-adrenocortical axis (HPA) and sympathetic-adrenal-medullar axis (SAM), increase the blood pressure and reduce HRV, and finally affect the cardiovascular system. A recent study analyzing 658 measurements of HRV obtained from 10 healthy males (18–40 years old) indicated reductions in HRV due to environmental LFN exposure. However, few studies have specifically examined the effect of LFN from wind turbines on HRV in healthy individuals; thus, this was the aim of this study. …

Besides distance from turbines, building materials also affect indoor LFN exposure. This work assessed the indoor LFN levels for several recruited households with different building materials and open/closed windows to illustrate their potential impacts. It is known that materials have different sound absorption coefficients. The overall sound pressure level and spectrum of external noise change when transmitted to the interior of a building. Mid- and high-frequency noises are selectively attenuated by roofs and walls, causing the building structure to function like an LFN pass filter. Outdoor to indoor noise reduction generally decreases with frequency, [but variations exist] related to housing construction and room dimensions. [Below 2.5 Hz, the outdoor to indoor noise reduction is zero. (“Outdoor to indoor reduction of wind farm noise for rural residences,” Kristy Hansen, Colin Hansen, and Branko Zajamšek [1])] Factors contributing to indoor/outdoor noise reduction also include structural resonances, room modes, and coupling between the air volume inside the residence and the stiffness of the walls, roofs, and ceilings. 

Chun-Hsiang Chiu, Shih-Chun Candice Lung, Nathan Chen, Jing-Shiang Hwang, & Ming-Chien Mark Tsou
Research Center for Environmental Changes and Institute of Statistical Science, Academia Sinica; Department of Atmospheric Sciences and Institute of Environmental Health, National Taiwan University, Taipei, Taiwan

Scientific Reports volume 11, article number: 17817 (2021)
doi:10.1038/s41598-021-97107-8 [2]

Download original document: “Effects of low-frequency noise from wind turbines on heart rate variability in healthy individuals [3]