笑--每个人都会的一个简单的动作。笑充满了我们的生活。它不仅表达了我们内心的愉悦，更有利于我们的健康。尤其是对心脏有好处，那到底好在哪里呢，让我们一起来看个究竟。

Laughter is good for the heart because it prolongs life while depression increases the risk of an early death, according to two new studies.

A good bout of laughter every day provides similar cardiovascular benefits as exercise because it stimulates the blood flow, said Michael Miller, who headed one research team at the University of Maryland.

On the other hand, depression -- or the lack of laughter -- is often linked to unhealthy habits such as smoking and drug addiction and increases the risk of death by 44 percent, said Wein Jiang, who led a study of 1,000 heart patients for the University of North Carolina.

Miller said laughter produced a "magnitude of change... in the endothelium... similar to the benefit we might see with aerobic activity, but without the aches, pains and muscle tension associated with exercise."

While laughter should not replace exercise, he said, "we do recommend that you try to laugh on a regular basis. Thirty minutes of exercise three times a week, and 15 minutes of laughter on a daily basis is probably good for the vascular system."