Natural sounds like birds singing or the pitter-patter of rain may have unexpected health benefits, research suggests.
Tuesday 23 March marks one year of coronavirus restrictions in the UK. While the "stay at home" regulation has prevented Britons from travelling to far-flung destinations, many have enjoyed getting back to nature, spending more time in their garden and local parks.
All this time outdoors may have done us some good, with US scientists linking so-called "natural soundscapes" to reduced pain, eased stress and better moods.
"In so many ways the COVID-19 [the disease caused by the coronavirus] pandemic has emphasised the importance of nature for human health" said co-lead author Rachel Buxton, from Carleton University in Ottawa, Canada.
"As traffic has declined during quarantine, many people have connected with soundscapes in a whole new way, noticing the relaxing sounds of birds singing just outside their window.
"How remarkable these sounds are also good for our health."
The scientists analysed 18 studies that investigated how exposure to natural sounds affects a person's health.
Results, published in the journal Proceedings of the National Academy of Sciences, suggest these soundscapes reduce stress and "annoyance".
They also "improve health and positive affective outcomes", like pain, mood and "cognitive performance".
Although unclear why this occurs, natural sounds may mask less pleasant noises that have been linked to hearing loss, high blood pressure, heart disease and irritability, according to the scientists.
Nature may also "replenish attention through unconscious, cognitive processes", with urban environments being more "fatigue-inducing".
"Nature does not require directed attention, and simultaneously elicits pleasure and relaxation," wrote the scientists.
"[The] stress recovery theory posits that nature may be perceived as less threatening and thus less arousing, leading to recovery from stress through autonomic response to nature."
Further research into the benefits of natural soundscapes is required, however.
"Most of the existing evidence we found is from lab or hospital settings," said co-lead author Dr Amber Pearson, from Michigan State University.
"There is a clear need for more research on natural sounds in our everyday lives and how these soundscapes affect health."
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In a second part of the experiment, the scientists analysed recordings collected from 221 sites at 68 national parks across the US.
"Little anthropogenic sound and abundant natural sounds" occurred at just 11% of the sites, which was largely down to a high number of visitors and the parks being in urban locations.
Animal, wind and water noises were still noted in the urban parks, however.
"Urban and other parks that are extensively visited offer important opportunities to experience natural sounds and are significant targets for soundscape conservation to bolster health for visitors", wrote the scientists.
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People could take advantage of some parks' quiet zones, as well as enjoying mindfulness walks where the main purpose is to listen.
"The positive health impacts and stress reduction benefits of nature are more salient than ever to help offset the concerning increase in anxiety and mental health issues," said co-author Professor George Wittemyer, from Colorado State University.
Experts warned early in the pandemic, the coronavirus outbreak could have a "profound" and "pervasive" impact on people's mental health for some time.
Buxton recommends people close their eyes and be mindful of the sounds they hear while visiting their favourite park.
"These sounds are beautiful and good for our health," she said. "They deserve our protection."
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