Swedish researchers have found that singers in a choir don't just unify their voices, their pulse rates also synchronize, their hearts beating together in relation to their breaths.
“As you are singing a phrase, your heart rate goes down, and then between the phrases, when you inhale, the heart rate goes up,” said Björn Vickhoff, the singer-songwriter-turned-neuroscientist who led the project.
Researchers at Sweden’s University of Gothenberg monitored the pulse rates of a group of choir singers as they worked through several musical pieces. They found that heart rates varied in coordination with the singers' breath, which meant that the speed of the heartbeats changed in unison.
Our hearts naturally speed up and slow down as we breathe, but Vickhoff explains this is just one part of our physiology that syncs up when people sing together.
“You’re synchronizing just about everything,” he said. “The melody, the text, the rhythm; you have to really adapt to each other. And there’s a counterpoint in that in your body, internally.”
Previous research has shown that activity of the vagus nerve - a cranial nerve which influences heart rate and breathing - synchronizes among singers in a choir. In addition, their moods may align, since slow, regulated breathing has a calming effect. It seems that singing together is cooperative on both physical and emotional levels.
This may provide insight into how singing can strengthen bonds among people. When a group is unified in action and behavior, its members become more cooperative, said Vickhoff.
According to these findings, singers are not only working together intentionally to create a unified sound, they are connected, unconsciously, by what their bodies are doing.
Perhaps this is one reason most world religions incorporate song and other acts of worship that involve synchronized breathing, like chanting mantras and group prayer. These communal rituals engage both the mind and the body, and could help us stick together.