The researchers found that each singer’s heartbeat was linked to the song’s melody – i.e. the speed and structure of the music. They also found that when the choir sang together, their heart rates tended to increase and decrease at similar times.

“As soon as the singing begins, (the hearts) start following each other,” Vickhoff told CNN in an e-mail.

Humming and performing the mantra as a group resulted in more synchronized heart rate variability, or HRV, than singing the hymn.

“The impression is that the heart cannot completely follow the respiration (guided breathing) when it has a more complex, hierarchical structure,” the study authors wrote.

The caveats

Four of the heart rate monitors malfunctioned, so only 11 sets of data were collected and analyzed. That’s a very small study sample to make any steadfast conclusions. The study will have to be duplicated with more participants. —