The old axiom, "Laughter is the best medicine," holds true when it comes to protecting your heart, according to a study conducted by the University of Maryland in Baltimore. Dr. Michael Miller, who conducted the study, says laughter releases chemicals into the blood stream that relax the blood vessels. In addition, hearty laughter reduces blood pressure and heart rate.

Miller, who is the director of the Center for Preventive Cardiology at the University, interviewed 150 patients who had suffered heart troubles and 150 who had not. Each patient was asked questions to measure their response in typical day-to-day situations. The results showed that individuals with heart problems were 40 percent less likely to respond with laughter.