Listening to music that makes you happy, especially if it's country music, may be good for your heart, a new study suggests.

In a small study of 10 participants, researchers found that music that makes the listener feel good causes the inner lining of the blood vessels to expand, which increases blood flow to the heart.

On average, listening to joyful music led blood-vessel dilation in the upper arm to increase by 26 per cent, while music that induced anxiety caused the vessels to narrow by six per cent.

The theory is that the positive emotions trigger the release of endorphins, the so-called happy chemicals, in the brain. This in turn activates the vessel-dilating chemical nitric oxide, lead study author Dr. Michael Miller told in an email interview.

Miller, who is director of preventive cardiology at the University of Maryland Medical Center, presented the research on Tuesday at the American Heart Association's Scientific Sessions conference in New Orleans.

Study participants were allowed to choose the type of music they would listen to in order to evoke feelings of joy and anxiety.

Many subjects chose country music artists, such as Hal Ketchum and Dwight Yoakam, to make themselves feel happy, as well as music from the "Footloose" soundtrack, Miller said.

Participants chose hard rock bands such as System of a Down and Disturbed to induce feelings of anxiety.

The study included four phases: listening to music that evoked happiness, listening to music that evoked anxiousness, listening to an audio relaxation tape and watching a video that induced laughter.

The same 10 participants participated in all phases of the research.

The researchers also found that laughter caused a 19 per cent increase in blood-vessel dilatation.

The relaxation tape was linked to a blood-vessel dilation increase of 11 per cent, but the investigators concluded that this was not statistically significant.

"I believe that stimulating positive emotions, especially over the long term, would improve vascular function and overall heart health," Miller said. "In addition to traditional heart prevention strategies, listening to joyful music and engaging in a good belly laugh on a regular, if not daily, basis would go a long (and inexpensive) way in this regard."