Songs that make our hearts soar can make them stronger too, US researchers reported on Tuesday.

They found that when people listened to their favorite music, their blood vessels dilated in much the same way as when laughing, or taking blood medications.

"We have a pretty impressive effect," said Dr Michael Miller, director of preventive cardiology at the University of Maryland Medical Center in Baltimore.

"Blood vessel diameter improved," he said. "The vessel opened up pretty significantly. You can see the vessels opening up with other activities such as exercise." A similar effect is seen with drugs such as statins and ACE inhibitors.

When blood vessels open more, blood flows more smoothly and is less likely to form the blood clots that cause heart attacks and strokes. Elastic vessels also resist the hardening activity of atherosclerosis.

"We are not saying to stop your statins or not to exercise but to add this to an overall program of heart health," said Miller, who presented his findings to a meeting of the American Heart Association in New Orleans.

Miller's team tested 10 healthy, non-smoking men and women, who were told to bring their favorite music.

They spent half an hour listening to the recordings and half an hour listening to music they said made them feel anxious while the researchers did ultrasound tests designed to show blood vessel function.

Compared to their normal baseline measurements, blood vessel diameter increased 26 percent on average when the volunteers heard their joyful music. Listening to music they disliked - in most cases in this group heavy metal - narrowed blood vessels by six percent, Miller said.

Miller said he came up with the idea after discovering the laughter caused blood to literally flow more smoothly.

"I asked myself what other things make us feel real good, besides calories from dark chocolate of course. Music came to mind. ... It makes me feel real good," he said.

Most of the volunteers chose country music but Miller said the style is not so important as what pleases each individual.

美国研究人员于本周二称，令人心情欢畅的音乐还能让心脏更加健康。

研究人员发现，当人们聆听他们喜爱的音乐时，血管就会扩张，跟大笑和服用血管扩张药物的效果相仿。

巴尔的摩马里兰大学医学中心的预防心脏病学主管迈克尔?米勒博士说：“这一效果非常显著，血管直径增大，血管扩张明显。我们知道，人们在从事体育锻炼等其他一些活动时血管也会扩张。”此外，服用他汀类药物和血管紧张素转化酶抑制剂也会出现类似效果。

人体血管扩张得越充分，血液流动就越畅通，导致心脏病和中风的血栓就越不易形成。血管弹性增强还可以预防动脉硬化。

迈克尔?米勒博士在新奥尔良举办的美国心脏病协会研讨会上公布了他的研究成果。他说：“这并不是说听听音乐就可以不吃药或者不锻炼了，但它可以作为保护心脏健康的一个良好的补充。”

研究人员对10位身体健康、不吸烟的男性和女性进行了测试，这些人都按照要求带来了自己平时最爱听的音乐。

研究人员让研究对象先听半小时自己带来的音乐，再听半小时让他们感到焦虑的音乐，并在此期间对他们进行血管功能超声波检测。

实验结果表明，研究对象在听自己喜爱的音乐时，血管直径比正常水平平均增大了26%，而在听他们不喜欢的音乐时（多为重金属音乐），血管较平时收缩了6%。

米勒称，他在发现“大笑可以使血流更通畅”这一事实后产生了这个想法。

他说：“我问自己，除了黑巧克力的热量外，还有什么能让我们感到愉悦呢？我想到了音乐，音乐能让我感到真正的愉悦。”

参与实验的多数志愿者自带的是乡村音乐，但米勒说，只要是自己喜欢，哪种类型的音乐并不重要。