As wind power generation becomes more important, experts at Flinders University are examining whether wind farm turbine noise can affect the sleep and wellbeing of nearby residents.
The researchers weighed up the results of five prior studies, in a review of existing literature on wind turbine noise effects on sleep.
While previous studies showed no systemic effects on common sleep marker - such as time taken to fall asleep and total sleep time – they did reveal some more subtle effects on sleep, such as shifts in sleep stages and less time in deep sleep.
"Comparing wind turbine noise to quiet background noise conditions showed no systematic effects on the most widely used objective markers of sleep, including time taken to fall asleep, total sleep time, time spent awake during the night and time spent asleep relative to overall time in bed," lead author Tessa Liebich said.
"However, some more subtle effects on sleep in some objective studies were established including shifts in sleep stages, less time spent in deep sleep and more time spent in light sleep."
The Adelaide Institute for Sleep Health study at Flinders researched sleep patterns in more than 70 volunteers in a carefully controlled in-laboratory experimental study, to investigate potential wind turbine noise impacts on sleep and daytime outcomes.
The study is through Australian NHMRC funding, and the final results are expected to be available around mid-2021.
Senior author Dr Gorica Micic said limited knowledge and data in this area emphasised a need for further well-controlled experimental studies to provide more conclusive evidence regarding wind turbine noise effects on sleep.
"Environmental noises, such as traffic noise, are well known to impact sleep," she said.
"Given wind power generation is connected with low frequency noise that can travel long distances and more readily into buildings, it is important to better understand the potential impacts of wind turbine noise on sleep."
This study aimed to comprehensively review published evidence regarding the impact of wind turbine noise on the most widely accepted objective and subjective measures of sleep time and quality.
Researchers explained that subjective sleep outcomes were not sufficiently uniform for combining data or comparisons between studies.
However, they found that the available self-report data appeared to support that insomnia severity, sleep quality and daytime sleepiness could be affected by wind turbine noise exposure, in comparison to quiet background noise.
The researchers deduced that firm conclusions were difficult to draw from the available studies, due to inconsistent study methods, variable outcome measures and limited sample sizes.
The new research paper, A systematic review and meta‐analysis of wind turbine noise effects on sleep using validated objective and subjective sleep assessments, has been published in Journal of Sleep Research.