Smiles lead to laughter, and as the saying goes, "Laughter is the best medicine." It's true: laughter improves heart functioning, reduces stress levels, has the power to heal relationships and is great for the mental outlo... more »ok. Researchers have found that laughter can assist your immune system as it lowers levels of stress hormones and decreases heart strain. Other research shows laughter helps the cardiovascular system by giving the heart and lungs can aerobic workout and can reduce stress by helping to relax muscles. Hospitals have found that therapeutic humor stimulates the release of endorphins, the body's own pain relievers and can decrease the average hospital stay by two days.« less