Newswise — New research conducted at Flinders University reveals that brief exposure to noise generated by wind farms and road traffic can lead to a slight rise in the number of individuals waking up from sleep, subsequently disrupting their sleep patterns.
Significantly, the recent study also demonstrates that wind farm noise does not cause more significant disruptions to sleep compared to road traffic. While road traffic noise exhibited slightly higher disruption levels at the loudest audio level, there was no substantial difference observed at the more typical noise levels.
In order to gain a deeper understanding of the effects of wind farm noise on sleep patterns among Australians, sleep researchers from Flinders University have conducted a comprehensive study, resulting in three new scientific publications. These publications shed light on the impact of wind farm noise on sleep and provide valuable insights for further research in the field.
To compare the sleep disruption responses caused by wind farm and road traffic noise, the study involved playing 20-second samples of both types of noise repeatedly during participants' sleep. Three different sound pressure levels were utilized, allowing for a comprehensive analysis of the participants' reactions to the two distinct noise sources.
In a separate phase of the study, the researchers examined the potential for sleep disturbance caused by longer 3-minute noise samples, which included isolated wind farm infrasound with very low frequencies. This specific investigation aimed to determine whether these extended noise samples had an impact on sleep patterns.
Furthermore, the researchers made a noteworthy discovery that wind farm infrasound, when presented at realistic levels, remained inaudible to the human ear during wakefulness and exhibited no indications of sleep disruption. These significant findings were presented at the International Conference on Wind Farm Noise in Dublin on June 22, 2023, and are currently awaiting peer review for publication in scientific journals.
The completion of the project required an extensive period of five years, during which over 460 sleep study nights were conducted. The study involved the participation of 68 individuals, each of whom spent seven consecutive nights within the sleep laboratory. This comprehensive approach ensured a substantial amount of data for analysis and provided a robust foundation for the research findings.
Participants for the study were carefully selected from four distinct groups. These groups included individuals residing in proximity to a wind farm, with and without reported sleep difficulties associated with noise exposure. Another group consisted of residents living near a bustling suburban road, while the remaining participants were individuals living in tranquil rural areas. By encompassing a diverse range of participants from these different groups, the study aimed to capture a comprehensive understanding of the effects of wind farm and road traffic noise on sleep patterns.
Dr. Bastient Lechat, one of the acoustics experts on the research team, explains the methodology employed in the study, stating, "To ensure the most accurate representation of wind farm noise features and levels, we utilized noise samples obtained from long-term measurements of actual wind farm noise. These samples were then reproduced within the controlled environment of the sleep laboratory, allowing us to replicate real-life noises with greater precision than what can be achieved in field studies, where wind and noise conditions often vary significantly. The study encompassed comprehensive assessments, including direct sleep measurements using electroencephalography (EEG), as well as hearing tests and various daytime listening tests." This approach ensured a thorough evaluation of the effects of wind farm noise on sleep patterns and related auditory functions.
According to Professor Peter Catcheside, a sleep expert from Flinders University and the chief investigator of the study, the findings indicate that both wind farm noise and road traffic noise have the potential to disrupt sleep. The extent of this disruption primarily depends on the loudness of the noise and the depth of sleep at the time of the noise exposure. These factors play a crucial role in determining the impact of noise on sleep quality and patterns.
"Nevertheless, it is important to note that the effects observed at realistic noise levels were relatively minor. Moreover, our research did not provide any indication that wind farm noise is inherently more disruptive to sleep when compared to road traffic noise. In fact, at the highest level of exposure, road traffic noise exhibited slightly greater sleep disruption than wind farm noise."
One of the primary objectives of the study, as mentioned by Professor Catcheside, was to investigate whether participants could perceive wind farm infrasound at realistic levels during wakefulness and whether any discernible changes in EEG-recorded brain activity could be observed when the infrasound was played during sleep.
"Our findings are consistent with previous studies and confirm that when played at
realistic levels, infrasound remains inaudible during wakefulness and does not result in detectable changes in EEG during sleep. This implies that infrasound is unlikely to be the cause of noise-related complaints associated with wind farms. Instead, it suggests that further investigation into the audible low-frequency rumbling and thumping components of wind farm noise is warranted in order to better understand their effects on sleep."
Professor Catcheside emphasizes that although the study provides robust evidence indicating that wind farm noise is not inherently more disruptive to established sleep compared to road traffic noise, it is important to note that individuals who are particularly sensitive to noise or easily annoyed may still experience difficulties in falling asleep when noise levels become noticeable. This highlights the significance of considering individual differences in noise sensitivity and subjective experiences when evaluating the impact of noise on sleep quality.
This research was supported by grants from the National Health and Medical Research Council and the Australian Research Council.
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