People who sing in a choir synchronize their heart rates, say researchers who want to investigate the medical potential of the effect.

Researchers had 15 healthy teens perform three different choral exercises while measuring heart rhythms:

  • Monotone humming with no instructions on when to breathe.
  • Singing the Swedish hymn "Härlig är Jorden" (Lovely is the Earth) with unguided breathing.
  • Chanting a slow mantra while breathing slowly between phrases.

The connection between breathing and heart rate is more pronounced with young people in good physical condition, researchers say. (Elaine Thompson/Associated Press)

Before and after the singing tasks, the subjects silently read an emotionally neutral text.

"Unison singing of regular song structures makes the hearts of the singers accelerate and decelerate simultaneously," Björn Vickhoff, lead author of the study, and his co-authors concluded in Monday's online issue of the journal Frontiers in Neuroscience.

The study stresses the importance of the body's autonomous nervous system to perceive, produce and communicate music, the researchers said.

The team suspects that singing imposes a calm and regular breathing pattern that affects heart rate variability.

In a second part of the study, five other people each had their heart rate and respiration recorded using more advanced equipment. Their hearts tended to accelerate and decelerate simultaneously during hymn and especially mantra singing.

"We already know that choral singing synchronizes the singers' muscular movements and neural activities in large parts of the body," Vickhoff said in a release. "Now we also know that this applies to the heart, to a large extent."

The medical term for fluctuation in heart rate in connection between breathing and heart rate is respiratory sinus arrhythmia or RSA.

Previous studies suggested that yoga breathing and guided breathing also produce RSA and have beneficial effects of blood pressure and heart rate. Similarly, one study suggested reciting the rosary prayer enhances blood pressure and heart rate variability.

One of the researchers was partially funded by the Swedish Research Council.