No proof that singing in a choir is good for heart

“Singing in a choir is as good for you as yoga,” The Daily Telegraph reports. Apparently, a study found that the regular breathing patterns choir singing requires, ‘can reduce the variability of your heartbeat’.

Unfortunately the claims made in the news can’t be supported by the evidence of this tiny new Swedish study.

The research looked at how singing affects the acceleration and deceleration of heart rate (heart rate variability or HRV).

Researchers also wanted to study the effect singing has on how well HRV synchronises with breathing (called respiratory sinus arrhythmia or RSA). The researchers say this synchronisation has a “biologically soothing” effect and is beneficial for cardiovascular function, and occurs during stress-busting activities such as yoga.

The researchers found that RSA is significantly higher during all singing conditions compared with baseline (no singing). And that singing in a choir with regular song structures made the heart rate of singers accelerate and decelerate simultaneously.

However, these findings should be viewed in the light of that fact that only 11 teenagers were involved in the analysis, and none of the teenagers were followed up over time. This means that we can’t say whether singing in a choir leads to better health.

Where did the story come from?

The study was carried out by researchers from the University of Gothenburg, Sweden and other institutions. Sources of funding were not reported, however one author is reported as being partially supported by a grant from the Swedish Research Council.

The study was published in the peer-reviewed journal Frontiers in Auditory Cognitive Neuroscience and has been published on an open access basis, so is free to download.

The study was picked up by a variety of papers and websites, some with attention grabbing headlines that singing in a choir is as healthy as yoga. These are not accurate reflections of the study findings.

This is likely to be a result of the media picking up quotes from the lead researcher who is reported as saying ‘songs with long phrases achieve the same effect as breathing exercises in yoga’.

The actual research did not perform comparisons between any possible health effects of choir singing or yoga.

What kind of research was this?

This was an observational study that investigated whether singing (a form of guided breathing) affects the acceleration and deceleration of heart rate (called heart rate variability or HRV). The study was also interested in investigating the effects of singing on the coupled effects of HRV and respiration, called respiratory sinus arrhythmia or RSA.

The researchers also performed a separate case study using only five of the participants. This was to further examine how song structure, respiration and heart rate were connected.

What did the research involve?

The researchers recruited 15 healthy male and female 18-year-olds. The participants were asked to perform the following three singing ‘tasks’ as part of a choir:

• hum a single tone and breathe whenever they needed to (considered non-synchronised singing and to be not co-ordinated)
• sing a hymn with free, unguided breathing (considered ordinary singing and to be co-ordinated to some degree)
• sing a slow mantra (a mantra is a repetitive chant) lasting 10 seconds with instructions to breathe only between phrases (designed to produce RSA and considered to be completely co-ordinated)

Each singing task was five minutes long, and there was a break of one minute between each task. The researchers included this break, they say, to ensure there was no lingering HRV effect from the previous singing task. Before the singing tasks and at the end of the tasks, participants were asked to silently read some emotionally neutral text for five minutes.

Heart rate was measured continuously throughout the study using ear clips that give an optical reading (eM wave technique), meaning that heart rate could be recorded simultaneously for all participants. Heart rate variability measurements were calculated using two techniques: root mean square of the successive differences (RMSSD) and low frequency to high frequency ratio (LF/HF). Frequency scores were also calculated to summarise the regularity of the heart rate fluctuations. The researchers then compared the singing tasks to each other using statistical methods.

The researchers also separately recorded information from five singers as part of a case study. These five performed the same singing tasks again together five times while the researchers collected information one person at a time using more advanced equipment called cStress. They individually recorded:

• heart rate
• respiration
• skin conductance – a measure of electrical resistance of the skin which is related to feelings of stress and arousal – skin conductance is a method used in lie-detector tests (which have not been proved to be accurate)
• finger temperature

The cStress equipment allowed for heart rate variability phase calculations between the five participants.

What were the basic results?

Of the 15 participants included in the study, only 11 were included in the final analysis as the other four experienced technical problems with their heart rate readings. The group and case studies both suggest that singing increases heart rate variability (HRV).

The main findings for each singing task were as follows.

Humming

Although humming did not produce a significant increase in heart rate variability (HRV) assessed by (RMSSD), the authors conclude that humming led to a significantly more regular HRV as measured by the frequency score. This means heart rate acceleration and deceleration is quite regular during humming, but the rate of fluctuation is highly individual.

Hymn

HRV, as measured by RMSSD, significantly increased during hymn singing compared to baseline and humming. Frequency analysis indicated HR fluctuations were not as regular as during humming, but that they occur at common shared frequencies for participants (0.1Hz).

Mantra chanting

Mantra chanting produced a significantly higher HRV (assessed using RMSSD) compared to all other conditions as well as significantly more regular HRV (on frequency score) compared with baseline and humming but not hymn singing. There was a highly regular HRV frequency at 0.1Hz for all individuals, which was significantly higher compared to humming or the hymn.

How did the researchers interpret the results?

In an accompanying press release, lead author, Bjorn Vickhoff says: “Singing regulates activity in the so-called vagus nerve which is involved in our emotional life and our communication with others and which, for example, affects our vocal timbre. Songs with long phrases achieve the same effect as breathing exercises in yoga. In other words, through song we can exercise a certain control over mental states.”

 The Telegraph reports him as saying: “Singing could provide a health boost by forcing participants to adopt a calm and regular breathing pattern, which in turn regulates the heartbeat”.

“We already know that choral singing synchronises the singers’ muscular movements and neural activities in large parts of the body. Now we also know that this applies to the heart, to a large extent.”

Conclusion

Few conclusions about the possible effects on wellbeing of choir singing can be drawn from this small study. As a brief observational study, it did not follow people over time, so it cannot show that lifestyle factors such as singing in a choir lead to particular wellbeing outcomes. Although there were some changes in HRV found, it is not known if these lead to cardiovascular benefits in the long-term. Other limitations of this study include:

• it was a very small study including only 15 participants who were all 18 years old, of these, only 11 were analysed, meaning generalising findings to larger or different populations is difficult
• the authors state they aimed to discuss how singing promotes wellbeing. No wellbeing measurements or quality of life was included in the study, so there are risks in drawing conclusions about well-being

The claims of the lead researcher that “songs with long phrases achieve the same effect as breathing exercises in yoga” are not supported by the evidence presented in this study.