Laughter yoga (Hasyayoga) is a modern exercise involving prolonged voluntary laughter. This type of yoga is based on the belief that voluntary laughter provides similar physiological and psychological benefits as spontaneous laughter. It is usually done in groups, with eye contact and much playfulness between participants. Intentional laughter often turns into real and contagious laughter.
Laughter Yoga was popularized by family physician Madan Kataria who modernized and simplified the work of earlier laughter pioneers,  who taught very similar concepts starting in the 1960s. Madan Kataria wrote about his experience in his 2002 book Laugh For No Reason.
The yoga is performed without any humorous reason to laugh, with one practitioner observing that "The mind does not know that we’re faking it."
Laughter yoga sessions may start with gentle warm-up techniques which include stretching, chanting, clapping, eye contact and body movement, to help break down inhibitions and encourage a sense of playfulness. Breathing exercises are used to prepare the lungs for laughter, followed by a series of ‘laughter exercises’ that combine the method of acting and visualization techniques with playfulness. Laughter exercises are interspersed with breathing exercises.
A 2019 review and meta-analysis in the field of laughter-inducing therapies suggests that they are more effective than humorous laughter and can improve depression. However, the quality of the evidence was low.
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- Kataria, Madan (2002), Laugh For No Reason (2 ed.), Mumbai, India: Madhuri International, ISBN 978-81-87529-01-9
- "Laughter Yoga: Relaxing, If a Bit Kooky". NPR.org. Retrieved 2019-04-21.
- Kanigel, Rachele. "How Laughter Yoga Heals, Plus 6 Fun Exercises to Try". Yoga Journal. Retrieved 2019-04-21.
- Wilson, Mary (23 June 2016). "Finding focus, relaxation and improved health through Laughter Yoga". ABC News 10. Retrieved 27 June 2016.
- Bokur, Debra. "What's So Funny? Yoga Journal". Yogajournal.com. Archived from the original on 2013-09-21. Retrieved 2013-08-02.
- van der Wal, C.N., Kok, R.N. (2019). Laughter-Inducing Therapies: A Systematic Review and Meta-Analysis. Social Science and Medicine, 232, p473-488. (open access). https://doi.org/10.1016/j.socscimed.2019.02.018
- Birklbauer, Walter (2011), Why Laughter Yoga or The Guitar Method: A Neurologic View, ISBN 3-8423-6907-7
- The Laughing Club of India documentary by Mira Nair about the club founded by Madan Kataria