How to relax with sound: what the studies show

Does listening to music lower stress?

On average, yes, by a moderate amount. The largest summary so far is a pair of meta-analyses by de Witte and colleagues, published in Health Psychology Review. They pooled 104 randomised trials with 9,617 participants, in which people given music were compared with control groups, and measured the difference as an effect size: how far apart the two groups ended, in standard deviations.

Music lowered both kinds of stress measure. On how stressed people said they felt, the effect size was 0.545. On the body's own stress signals, it was 0.380 overall, and largest for heart rate, at 0.456. An older meta-analysis by Pelletier, of 22 studies, found a similar result, 0.67, for music on its own and for music used with a relaxation technique.

Effect of music on stress measures

Measure	Effect size
How stressed people felt, every self-rated measure	0.545
Heart rate	0.456
All body measures	0.380

Those are averages over trials of many kinds of music, many settings and many kinds of listener, so they say what tends to happen, not what will happen to you. They also say nothing about any one pitch. None of the trials tested a single tone, and the sounds that follow on this page are offered in that light: as sound to rest with, chosen to fit what the research describes.

What kind of music relaxes the body most?

Slow music, and above all a pause. In a laboratory study at the University of Pavia, Bernardi, Porta and Sleight recorded the breathing, heart rate, circulation and blood flow to the brain of 24 young adults, 12 practising musicians and 12 others, while they lay on their backs with headphones on and their eyes closed. Each heard six styles of music in random order, from an Indian raga at 55 beats a minute through Beethoven, Webern, rap and techno to a Vivaldi presto at 150, with a two-minute pause inserted at random.

What changed the body was speed. Faster music quickened breathing and heart rate, whatever its style. In the authors' words, "Music induces an arousal effect, predominantly related to the tempo." Classical music and techno at similar speeds did much the same. The raga, the slowest piece, brought a larger fall in heart rate than any other track. And what people liked made no difference: "These results were not influenced by the music preferences of the subjects."

Why can silence relax you more than music?

Because the pause did what no track did. In the same study, the two minutes without music brought heart rate and breathing down below where they had been at rest before any music began, "even below baseline", in the authors' words. They conclude that slow or meditative music can relax, and that "relaxation is particularly evident during a pause."

One reading is that music first holds attention, and the body lets go when it stops. Whatever the reason, it suggests a simple habit: let a listening session end in a few minutes of quiet, rather than switching straight to something else.

Are nature sounds more relaxing than noise?

In the few studies that have tested it, people recovered from stress a little faster to nature sounds. In Stockholm, Alvarsson, Wiens and Nilsson gave 40 people a stressful mental arithmetic task and then played them a fountain with birdsong, or road traffic noise, while they recovered. Skin conductance, a measure of the body's alarm system, settled faster during the fountain and birds at 50 dB than during traffic noise at the same level, and faster even than quieter background noise at 40 dB. Heart rate variability showed no difference.

A review by Buxton and colleagues found 36 publications on the health effects of natural sounds, and a meta-analysis of 18 of them pointed the same way, to less stress and annoyance. Water and music do not always agree, though. In a trial by Thoma and colleagues, 60 women heard relaxing choral music, the sound of rippling water or nothing before a stress test. Cortisol, which the body releases under stress, rose least after the water and most after the music, while another stress marker, salivary alpha-amylase, returned to its starting level faster after the music than after silence. Heart rate and how stressed the women felt did not differ between the three groups.

Does it matter why you listen?

It seems to. Linnemann and colleagues followed 55 university students through an ordinary week and an exam week, asking four times a day what they had been listening to, why, and how stressed they felt, and taking saliva samples from some of them. Stress was lower after music in general, and "The most profound effects were found when 'relaxation' was stated as the reason for music listening", with lower cortisol as well. Choosing to listen in order to rest, not as background to something else, went with the largest change.

How does breathing fit in?

Breathing is the part of relaxing that sound can slow down or speed up. In Bernardi's study breathing quickened with faster music and eased with slower music. Most people breathe between 9 and 24 times a minute, and the heart speeds up a little on each in-breath and slows on each out-breath. As Lehrer and Gevirtz describe, those swings in heart rate grow largest when breathing slows to about six breaths a minute, one every 10 seconds.

A systematic review by Zaccaro and colleagues gathered 15 studies of slow breathing, under 10 breaths a minute, in healthy people. Slower breathing went with greater heart rate variability and with people reporting more comfort and relaxation. The studies were small and varied, and none of them was about sound, but they explain why a slow, steady sound and a slow breath sit well together.

Nothing needs forcing. If your breathing slows while you listen, let it; if a slower pace feels uncomfortable, breathe as you normally do. The tones described below swell so gently and so slowly, three times a minute, that they set no pace of their own to follow.

What does the Need to unwind page play?

The Need to unwind page plays three tones, each with a Strings mode: 285 Hz, the Solfeggio tone Harmonance calls the restoration theme; 432 Hz, a tuning often discussed in music and meditation; and Neptune at 211.44 Hz, which Hans Cousto's table derives from Neptune's 164.79 year orbit, raised 40 octaves. The guides to 285 Hz, to 432 Hz and to Neptune's tone tell where each number comes from.

The research points to slow, steady and quiet, so Harmonance measured how steady the page's own sounds are. Each tone file holds almost still. Measured second by second for three minutes with the broadcast loudness meter, EBU R 128, the 285 Hz tone moves 0.8 LU from its quietest second to its loudest, the 432 Hz tone 0.8 LU and Neptune 0.7 LU. Each rises and falls by less than 1 dB once every 20 seconds, and its strongest overtone, an octave up, sits 23.1 dB below the tone itself.

How far each sound's loudness moves in three minutes

Tone	Tone (LU)	Strings mode (LU)
285 Hz	0.8	8.9
432 Hz	0.8	8.5
Neptune, 211.44 Hz	0.7	10.2

Download the loudness readings (CSV)

The strings move as music does. At the page's default level each Strings mode plays at the same overall loudness as its tone, -22.7 to -22.9 LUFS, but over three minutes it swells and thins across 8.9 LU for 285 Hz, 8.5 LU for 432 Hz and 10.2 LU for Neptune, never by more than about 3.6 LU from one second to the next. Neither mode has a beat. The tone is the nearer of the two to silence, since almost nothing in it changes; the strings are the nearer to slow music. Try both and keep the one you like to rest with.

Is there a best frequency for relaxation?

No study has found one. The trials above played recorded music or recorded nature, and none compared one pitch with another. The nearest is a small online study by Kumar, Abhayapala and Samarasinghe, in which 37 adults heard twelve pure tones from 110 to 963 Hz for 20 seconds each and rated, on a scale of 1 to 10, how calm, happy, sad and angry each sounded. Calm ratings fell as the pitch rose, from about 8.3 at 110 Hz to 1.9 at 963 Hz, with 285 Hz at 6.7. That is how a tone sounded to a small group for 20 seconds, not what it did to them.

The US National Center for Complementary and Integrative Health reads the wider field the same way: "However, because much of the research on music-based interventions is preliminary, few definite conclusions about their effects have been reached." For the research on sound and health more broadly, see the guide to what sound healing research shows.

How do you relax with sound, step by step?

• Choose slow and steady. Pick a sound with no beat to follow, or a slow one: a single tone, slow strings, or water and birdsong. In Bernardi's study the slowest music settled the body most and faster music raised it.
• Keep it quiet. The nature sound in Alvarsson's study played at 50 dB, below the 60 to 70 dBA that the US National Institute on Deafness and Other Communication Disorders gives for normal conversation. The same institute says sounds at or below 70 dBA, "even after long exposure, are unlikely to cause hearing loss". Relaxing needs far less: just loud enough to hear.
• Lie back and close your eyes. That is how the listeners in Bernardi's study heard the music, with nothing else to do.
• Listen to rest, on purpose. In Linnemann's study the change was largest when relaxation was the reason for listening. Give the sound your attention for ten minutes, not the back of your mind.
• Let your breathing slow, if it wants to. Around six breaths a minute is where the body's heart rate swings are largest; any pace that feels easy is fine.
• Avoid interruptions. Adverts and notifications break the stillness. Under Harmonance's most-watched video, one listener put it plainly:

The commercials killed it. It takes you out of your zone

That is why every sound on harmonance.com plays free and without adverts. And end in silence: in the Pavia study, the pause was where the body settled furthest. If a tone does not suit you, switch it off; no sound is worth sitting through. Harmonance Studio adds a timer, so the sound can end on its own, and the guide to Harmonance Studio shows how to set one.

For winding down at night, the guide to music and sleep covers what the sleep trials found. For a busy mind, the Overthinking page offers three more tones, and the guide to sound baths covers relaxing with sound in a group.

Sources and limits

The figures for music and stress come from meta-analyses of trials of recorded music of many kinds, with results that varied from trial to trial; the studies of tempo, silence, nature sounds and breathing are small, and several used only young adults. No study has tested 285 Hz, 432 Hz, Neptune's tone or any single pitch for relaxation. The loudness readings come from the site's own audio files, measured by Harmonance at the page's default level, without the quiet room sound the page adds beneath the strings; how loud either is in your room depends on your device and its volume. The listener comment is one person's words, quoted whole and without a name, not a finding.

1. de Witte and colleagues, music and stress-related outcomes, two meta-analyses: 104 trials, 9,617 participants.
2. Pelletier, music and arousal due to stress, a meta-analysis: 22 studies.
3. Bernardi, Porta and Sleight, the importance of silence: tempo, breathing and the pause.
4. Alvarsson, Wiens and Nilsson, stress recovery to nature sound and noise.
5. Buxton and colleagues, the health benefits of natural sounds: 36 publications reviewed.
6. Thoma and colleagues, music, rippling water and the stress response.
7. Linnemann and colleagues, music listening and stress in daily life.
8. Lehrer and Gevirtz, how heart rate variability biofeedback works: breathing near six a minute.
9. Zaccaro and colleagues, slow breathing, a systematic review.
10. Kumar, Abhayapala and Samarasinghe, how twelve pure tones sounded to 37 listeners.
11. NCCIH, music and health: what you need to know.
12. NIDCD, noise-induced hearing loss: safe listening levels.
13. Cousto, tuning data for the Earth, Moon, planets and Sun: Neptune's tone.