Mar 2, 2011

Cardiac Rhythms Synchronize with Music

       Music, particularly pieces that contain crescendos or gradual increases in volume, elicits synchronized cardiovascular and respiratory responses in young people that are similar in both musicians and nonmusicians, according to new research.

It is well-known that music can elicit strong positive or negative emotions, but this new research shows that music is also linked to unconscious physiological responses, said the study's lead author, Luciano Bernardi, MD, professor of internal medicine at Pavia University, in Italy.

"Here we show, probably for the first time, that there is a continuous interaction between the music dynamics and our cardiovascular system, whether there are conscious emotions or not," Dr. Bernardi said in an interview.
These findings could have implications for the potential use of music as a therapeutic tool, he added. "We know now that music can affect the cardiovascular system, and if we understand how this works, then we can use it," he said.
The research was published online June 22 and in the June 30 issue of Circulation.

Operative Music
Researchers tracked the cardiovascular and respiratory profile of 24 healthy subjects aged 24 to 26 years old, of whom 12 were experienced choristers and 12 were age- and sex-matched controls with no musical training.

Hooked up to an electrocardiogram (ECG) and with their eyes closed, the subjects listened to various pieces of music with headphones. The pieces included:
  1. An adagio from Beethoven's Ninth Symphony, a well-known orchestral piece; 
  2. "Nessun dorma," an emotional and lyrical operatic aria from Puccini's Turandot
  3. a solo vocal piece from 1 of Bach's cantatas, a more "intellectual" selection; 
  4. an aria from Verdi's Nabucco, which has rhythmic phrases; 
  5. and another aria from Verdi's La Traviata, also a rhythmic piece. 
  6. The subjects were also exposed to 2 minutes of silence.
Researchers selected these pieces because they contain several changes in music dynamics — for example, crescendos, decrescendos, pianos, and fortes, etc, said Dr. Bernardi. "This is the ideal type of music to use if you want to see whether the same variation is mirrored in the cardiovascular and respiratory systems," he said. "And of course, operatic music is part of our music tradition in Italy."

While subjects listened to the music, researchers monitored their ECG, blood pressure, cerebral blood flow, respiration, and skin vasoconstriction. They collected individual data as well as averages for each of the 2 groups separately as well as all 24 subjects together.
To measure conscious emotional arousal, subjects were asked to rate the intensity of emotion and the novelty and pleasantness of the musical pieces on a 5-point scale. They also reported on whether they felt "chills" or other strong feelings in response to each track.

No "Chills"
The researchers found that there was little or no emotional involvement in the music, and none of the subjects reported chills in response to the music.
But the investigators did find subconscious reflex autonomous responses. Almost every musical crescendo induced progressive skin vasoconstriction along with increases in blood pressure and heart rate.
Correlations between cardiovascular variables and music profile were particularly evident during the aria "Nessun dorma," which is characterized by 3 progressively stronger crescendos. "We found that there were a lot of correspondences, particularly during the part of the musical track that has those crescendos," said Dr. Bernardi.
Conversely, during the slower or silent phases, there was progressive skin vasodilation and reductions in heart rate and blood pressure, indicating progressive relaxation.

Similar Responses
Although musicians tended to have a greater response than control subjects to more "intellectual" music, for the most part, the cardiac profile of musicians was the same as that of nonmusicians. "Everyone tended to respond in the same way, which suggests that whether you like it [the music] or not, these particular tracks have an effect that is common to everybody," said Dr. Bernardi.
As for respiration, there tended to be a correlation between music and breathing. For certain pieces, the respiratory signal closely tracked the amplitude of the music "envelope," indicating that the depth of respiration could be influenced tightly by music, at least during crescendos, said the authors. Musicians had a somewhat higher correlation for some musical pieces than nonmusicians.
Dr. Bernardi surmised that a study using music from other cultures – for example, Chinese or Arabic — would produce similar findings. "I would suggest that pretty much everything would be the same using people with a different musical system because it [physiological reaction] is dependent not on emotions" but rather on the body's reactions that are independent from emotional responses, he said.

Better Explanation
Music is already being used as a therapy in various fields, but until now little was known about how it works. "We think we can now provide an explanation of how it could work and therefore provide a better way of using it," said Dr. Bernardi.

Other research has shown that music reduces stress, boosts athletic performance, and enhances motor skills in people with neurological impairments. Music can also provide physical benefits by acting as a distraction so patients may be able to exercise for longer periods of time.
An earlier study by Dr. Bernardi and his colleagues found that faster tempos resulted in increased breathing, heart rate, and blood pressure, all of which decreased when the music was stopped.
The next step for his research group is to repeat the current study using an older patient population — those over age 70 years. The selection of musical pieces for this new study will include rock music, said Dr. Bernardi.

Provocative Findings
For his part, Barry Franklin, MD, director of cardiac rehabilitation and exercise laboratories at William Beaumont Hospital, in Royal Oak, Michigan, called the study "provocative."

He said he would like to see similar studies done on coronary patients like the ones he deals with on a daily basis to see whether the physiologic responses are the same. If they are, there may be some huge implications, he said. In patients with tremendous functional deficits, even very small changes in blood pressure, blood flow, heart rate, and so on may produce meaningful adaptations and improvements in those individuals, Dr. Franklin noted.

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