When people sing in a choir their heart beats are synchronised, so that the pulse of choir members tends to increase and decrease in unison, scientists have found.
Choral singing's positive effects on health may arise through singing "imposing" a calm and regular breathing pattern which has a dramatic effect on heart rate variability - something that, in its turn, is assumed to have a favourable effect on health, researchers believe.
The study from the Sahlgrenska Academy at University of Gothenburg examined the health effects for choir members.
In December 2012, Bjorn Vickhoff and his research group brought together fifteen 18-year-olds at Hvitfeltska High School in Gothenburg and arranged for them to perform three different choral exercises: monotone humming, singing the well-known Swedish hymn "Harlig ar Jorden" (Lovely is the Earth) as well as the chanting of a slow mantra.
The heart rhythm of the choir members was registered as they performed in each case.
The results from the study showed that the music's melody and structure has a direct link is linked to the cardiac activity of the individual choir member; to sing in unison has a synchronising effect so that the heart rate of the singers tends to increase and decrease at the same time.
"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," said Bjorn Vickhoff, lead author of the study.
"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," Vickhoff said.
Choral singing's positive effects on health and well-being are testified by many, although it has only been studied scientifically to a lesser extent.
"In the case of controlled breathing, the heart rate or pulse decreases when breathing out during exhalation in order to then increase again when breathing in during inhalation. This is due to breathing out exhalation activates the vagus nerve that lowers the heart rate which slows down the heart," Vickhoff said.
"The medical term for this fluctuation in heart rate the connection between breathing and heart rate is RSA and it is more pronounced with young people in good physical condition and not subject to stress.
"Our hypothesis is that song is a form of regular, controlled breathing, since breathing out exhaling occurs on the song phrases and breathing in inhaling between these.
"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," Vickhoff said.
The study was published in the journal Frontiers in Neuroscience.