Monitoring the heart rates of 15 choir members as they performed a variety of choral works, researchers at Gothenburg University found as the members sang in unison their pulses began to speed up and slow down at the same rate, the BBC reported Monday.
Writing in the journal Frontiers in Psychology, the scientists said it appeared the matching heart rates occur because the singers were coordinating their breathing.
"The pulse goes down when you exhale and when you inhale it goes up," researcher Bjorn Vickhoff said.
"So when you are singing, you are singing on the air when you are exhaling so the heart rate would go down. And between the phrases you have to inhale and the pulse will go up.
"If this is so then heart rate would follow the structure of the song or the phrases, and this is what we measured and this is what we confirmed," he said.
The more structured the choral piece, the more the singers' heart rates were synchronized, the researchers said, with slow chants producing the most synchrony.