Principal investigator Dr. Michael Miller said the music selected by study participants because it made them feel good caused tissue in the inner lining of blood vessels to dilate, or expand, in order to increase blood flow. This healthy response matches what the same researchers found in a 2005 study of laughter.

However, when study volunteers listened to music they perceived as stressful, their blood vessels narrowed, producing a potentially unhealthy response that reduces blood flow.

Ten healthy, non-smoking volunteers -- 70 percent male, average age 36 years -- participated in all phases of the randomized study. The researchers used a blood vessel dilation test, which measures how well the blood vessel in the upper arm responds to the sudden increase in flow, with the result expressed as a percentage change in vessel diameter.

The study found that compared to the 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 6 percent.

The finding was presented at the American Heart Association scientific sessions in New Orleans.