Laughter yoga is a practice started in India in 1995 to let people experience the medical benefits of laughter. The sessions are based on medical research indicating the human body apparently cannot tell the difference between real laughter and fake laughter.
Some of the benefits reportedly include an immune system boost, increased oxygen intake, increased “feel good” hormones and reduced stress hormones. To get the full benefits, a person must laugh heartily for a sustained period of time, about 15 minutes.