laughing exercise

When you laugh, like, REALLY laugh, there are a number of factors that make hearty laughter a good workout for you. Happiness and elation cause the brain to release a chemical in the body that helps increase bloodflow, burn surface fats from your body, increase muscle tone, and reduce cholesterol. Laughing is also an obvious muscle workout. For a hearty laugh, each "Ha" can be equal to a sit-up or crunch.

maybe when people laughing their body can preduce a kind of hormone,and this kind of hormone is good for human's body~~actually,when you feel happy you can laugh,so if you laugh it means you have a good mood,that is enough