Researchers at the University of Maryland in Baltimore found that when people watched a tense, sad movie, their blood vessels constricted. But when they watched something lighter and then laughed, the blood vessels opened up. This allows blood to flow more freely.
While this is a good thing, it may not prove laughing is going to save us from a heart attack. But what researchers do know is that easier blood flow can be a marker for a reduced risk of cardiac events.
The research was presented at a meeting of the European Society of Cardiology.