I love the sound of the tweeting of birds. It helps me relax. It feels heavenly to me. It’s one of the things I find most relaxing when I’m out walking our dog, Daisy. She’s a 1-year-old Bichon Frisé.
At this moment, I can hear them. There’s tweets, whistles, and songs. But I’m not on a walk. I’m sitting at my desk and the sound is playing out of my iPhone. I’m listening to a track of nature sounds.
Even though I’m not outside in nature, the sounds relax me all the same.
The human nervous system recognises nature sounds regardless of where they come from and tends towards a relaxed state all by itself.
Recently, scientists have begun to study this. They typically compared the nervous system or pain responses of people listening to natural sounds with the responses when they’re not listening to any sounds. Sometimes they do it in a hospital setting when a person is undergoing a procedure and typically feels anxious or feels physical pain. Other times it’s in a lab setting.
As an example, 60 patients receiving mechanical ventilation were randomised to either receive standard care or standard care with the addition of listening to nature-based sounds on headphones.
The patients could choose the sounds. They could listen to birdsong, forest sounds, waterfalls, streams, or soothing rainfall.
Throughout the time they listened and for 30 minutes afterwards, those patients had much less anxiety and agitation than those who didn’t listen to the sounds. And their blood pressure was lower.
Nature sounds impact on our experience of pain too. One study was a double-blind randomized controlled trial involving mothers who were undergoing caesarean section. They were randomised into three groups.
The first group listened to nature sounds through headphones. The next group also wore headphones, but that didn’t have any sounds playing. The third group didn’t wear headphones, nor did they listen to any sounds. All the women received the same care. This set up allowed a good comparison to be made.
It turned out that the women who listed to nature sounds had significantly lower pain levels than the other two groups.
In another study, scientists examined the effect of nature sounds on stress responses. Volunteers did a stressful task (mental arithmetic). The researchers wanted to measure how long it took their nervous systems to return to normal, baseline levels and whether the sound they listened to would have any bearing on this.
To do this, they split the volunteers into four groups and asked each group to listen to a different sort of sound.
One group listened to sounds of singing birds and water in a fountain at a low volume of 50 decibels. This volume level is about as loud as a quiet conversation between two people.
The next group listened to traffic noise at 80 decibels, which is the noise level you would expect in a busy city centre road full of traffic.
Group 3 listened to traffic sounds of a lower volume or 50 decibels, the sort of level you might hear through your window if you lived in a city.
The last group listened to ambient noise of a ventilation system at 40 decibels, to simulate a typical office environment.
After the stressful task and while now listening to the sounds, the volunteers’ nervous systems returned to baseline much faster when they listened to nature sounds than when listening to any of the other sounds.
In the Czech Republic, scientists invited volunteers to walk a route around the historic city of Hradec Králové while wearing headphones that played either birdsong or traffic noise. A separate group just walked the route without headphones so a comparison could be made. The researchers timed how long it took them to walk the route.
Listening to birdsong actually slowed the walking pace of the volunteers, while traffic noise speeded them up.
Nature sounds vs relaxing music
Some skeptics have tried to argue that all of the above kinds of studies have nothing to do with nature, per se, but that the effects are simply because nature sounds sound relaxing. They say any kind of relaxing music will have the same effect. This is partly true but not entirely true.
It’s partly true in the sense that other kinds of relaxing music are, well, relaxing, so of course they will help us feel relaxed. But research shows that nature sounds and typical calming music sounds impact us in different ways by working through different biological pathways.
For example, in one study, volunteers either listened to sounds of nature or they listened to relaxing music. Both groups were compared against a group who didn’t listen to anything.
Each person completed a stressful task and the researchers measured how long it took their nervous systems to return to baseline. They also took measurements of the stress hormone cortisol as well as salivary amylase, an enzyme that increases during stress.
Cortisol is an ancient stress hormone, but salivary amylase is a more recent development in the human species. It coincided with the advent of cooking food and consuming starchy foods as we developed agriculture.
Both sounds relaxed the volunteers, but the nature sounds achieved it a little faster. Levels of cortisol were lower too in those who listed to the nature sounds. However, levels of salivary amylase returned to baseline faster in those who listened to relaxing music.
As I wrote in another blog (The Healing Power of Nature), the human nervous system has adapted to natural sounds over eons so we would expect natural sounds to work with more ancient pathways. Relaxing music, on the other hand, is a relatively recent experience for humans so we might expect it to work with some different biological pathways. The study suggested that this seemed to be the case.
Both natural sounds and relaxing music relaxed the volunteers. They just plucked slightly different notes in our biology in the process.
Which of natural sounds or relaxing music is more relaxing, I think, is a personal choice. They both work. Personally, I find natural sounds relax me faster. On the other hand, I find relaxing music is better for meditating.
I frequently work at my laptop with nature sounds playing in the background. I wrote much of Why Woo-Woo Works in this way, in fact, where I included a chapter of research on the healing effects of nature.
The above research on natural sounds is not to say that relaxing music doesn’t have clinical benefits. In fact, a review of 26 randomised controlled trials on the use of relaxing music with coronary heart disease patients showed that the music produced overall reductions in anxiety, heart rate, respiratory rate, blood pressure, and quality of sleep following their surgery.
Regardless is which is best, it’s clear that the human nervous system is tuned to the sounds of nature.
When we hear her tune, the nervous system relaxes all by itself. Tension and stress are replaced by calm, and the immune system and pain management systems begin to work more optimally.
Copyright 2022 David R. Hamilton PhD.