Washington, Nov 13: Listening to joyful music may be really good for your heart, according to the latest study.
University of Maryland School of Medicine researchers (Baltimore) have shown that emotions evoked by joyful music have a healthy effect on blood vessel function.
Music, selected by participants because it brought them a sense of joy, caused tissue in the inner lining of blood vessels to expand and increase blood flow.
This healthy response matches what the same researchers found in a 2005 study of laughter. Conversely, when volunteers listened to music perceived as stressful, their blood vessels narrowed, reducing blood flow.
"We had previously demonstrated that positive emotions, such as laughter, were good for vascular health. So, a logical question was whether other emotions, such as those evoked by music, have a similar effect," said principal investigator Michael Miller, director of preventive cardiology at Maryland.
"We knew that individual people would react differently to different types of music, so in this study, we enabled participants to select music based upon their likes and dislikes."
Ten healthy, non-smoking volunteers (70 percent male, average age 36 years) participated in all phases of the randomised study.
There were four phases. In one, volunteers listened to music they selected that evoked joy. The volunteers brought recordings of their favourite music to the laboratory, or, if they did not own the music, the investigators acquired the recordings.
Another phase included listening to a type of music that the volunteers said made them feel anxious.
In a third session, audio tapes to promote relaxation were played and in a fourth, participants were shown videotapes designed to induce laughter.
Each volunteer participated in each of the four phases, but the order in which each phase occurred was determined at random.
To minimise emotional desensitisation, the volunteers were told to avoid listening to their favourite music for a minimum of two weeks.
"The idea here was that when they listened to this music that they really enjoyed, they would get an extra boost of whatever emotion was being generated," said Miller.
Prior to each phase of the study, the volunteers fasted overnight and were given a baseline test to measure what is known as flow-mediated dilation.
During the blood vessel dilation test, blood flow in the brachial artery, located in the upper arm, is restricted by a blood pressure cuff and released, according to a Maryland release.
An ultrasound device measures how well the blood vessel responds to the sudden increase in flow, with the result expressed as a percentage change in vessel diameter.
After the baseline test, each volunteer was exposed to the music or humorous video for 30 minutes.
Additional dilation measurements were obtained throughout each phase to
assess changes from baseline.
Participants returned a minimum of one week later for the next phase. Sixteen measurements per person or a total of 160 dilation measurements were taken during the course of the study, which took six to eight months to complete.
Compared to baseline, the average upper arm blood vessel diameter increased 26 percent after the joyful music phase, while listening to music that caused anxiety narrowed blood vessels by six percent.
"I was impressed with the highly significant differences both before and after listening to joyful music as well as between joyful and anxious music," says Dr. Miller.
The results were presented at the Scientific Sessions of the American Heart Association on November Tuesday in New Orleans.
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