Adding to the myriad benefits bestowed by nature, scientists report that natural sounds alone – such as waterfalls and birdsong – are good for our health.
In a synthesis of studies, published in the journal Proceedings of the National Academy of Sciences, they found that natural sounds can deliver health benefits such as reduced pain, lower stress, enhanced mood and better cognitive performance.
“The sounds of nature have long generated powerful reactions in human beings,” write Rachel Buxton, from Carleton University, US, and colleagues.
“Sounds confer a sense of place, connect people to nature, and increasing evidence suggests that natural sounds are important for human health and wellbeing.”
In their review and pooling of data from 36 studies, they found that water sounds were most effective at boosting mood and cognition, while birdsong alleviates stress and annoyance.
“The sounds of birds are highly soothing to people, as well as the sounds of moving water or a breeze through trees or meadows,” says senior author George Wittemyer.
There’s also evidence that these sounds might help mask the negative impacts of anthropogenic noise, such as cars, trains and planes – listening to natural sounds paired with human noise had better health outcomes than listening to noise alone.
Noise can interfere with animals’ ability to communicate and survey their environment, cause hyperarousal and impact their behaviour, physiology and fitness – and it can also be detrimental to humans, affecting hearing, heart health and tranquillity.
Those noises and their impacts on wildlife have been a long-standing focus of the team as part of their work on sound and light ecology, and it struck them that the reverse could be important to explore.
“We realised that there remained superb natural areas which also are characterised by the prevalence of natural sounds,” says Wittemyer, “and that there was a strong parallel between the negative impacts of noise to wildlife and on people’s experiences and even health.”
Following their review, the team investigated the distribution of natural and human-caused sounds at 221 sites in 68 US national parks from ten years of recordings by students at Colorado State University in collaboration with the National Park Service.
They found that areas rich with natural sounds and with little interference from human noise are remote, only occurring at 11.3% of the sites. Parks near urban areas or with heavy visitation were more likely to be inundated with noise.
“That means that many park visitors are not reaping the health benefits found in more quiet spaces,” says Buxton.
As well as their direct impacts, the team says the noises reduce birdsong, thus further depleting the soundscape of natural acoustics.
Innovative programs to increase people’s appreciation of natural sounds already exist, such as soundwalks and excursions to quiet zones where they are encouraged to listen and appreciate the parks quietly. The Cathedral Grove in Muir Woods, California, for example, is designed as a quiet place where visitors can take refuge.
Awareness of their health benefits has prompted the authors to renew calls for a concerted focus on protecting natural soundscapes and making them more accessible.
Natalie Parletta is a freelance science writer based in Adelaide and an adjunct senior research fellow with the University of South Australia.
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