Laughter is an important human behaviour that has evolutionary benefits. It can reduce stress, anxiety and tension, and improve mood.
Laughter has been proven to cause positive physiological changes like increased heart rate, blood pressure, respiration rate and oxygen saturation. These changes are typically positive because they cause a decrease in the stress hormone cortisol. The increased levels of oxytocin that it causes also trigger a release of serotonin which improves mood and can make people more social with their interactions. The effects of laughter on physical health have been studied extensively by professors at the University of Missouri-Columbia who discovered that laughter can help to increase bone density while decreasing the risk for osteoporosis and fractures.