In a yellow room on the second floor of GW's Center for Integrative Medicine, Siddharth Shah instructs his class to repeat after him - "ho ho" and "ha ha ha."
"Okay, everyone, stand up, and ho ho, ha ha ha; HO HO, HA HA HA," said Shah, as he leads his group through a variety of yoga breathing exercises and laughing exercises.
Laughter therapy, otherwise known as laughter yoga, is a concept of body-mind medicine that combines the breathing techniques of yoga and laughter exercises. First developed by Madan Kataria, a physician from Mumbai, India, laughter therapy sessions can now be found all over the world, mostly in India, Denmark, the Netherlands, Australia and the U.S.
Shah got involved with laughter therapy while visiting relatives in India three years ago.
Participants come from different occupations and backgrounds. The group caters to people with medical illnesses, those affected by trauma and people who are generally stressed. Whatever their condition, Shah said everyone's reason for attending is similar - to feel good.
"I got Lyme Disease and noticed that if I went to a funny movie it made me feel better," said Ann Laferty, 49, a software developer.
At first, some group members were forcing their laughter, but by the end of the hour-long session, some left shaking uncontrollably or crying from laughing so hard.
Sebastien Gendry, operations director of Laughter Yoga and international managing director of the American School of Laughter Yoga, said scientific research has proven that the human body does not differentiate between artificial and genuine laughter and both types will produce the same physiological response.
"Going through the motions (of laughing) helps trigger your brain into the real feeling," Shah said.
"The nerves in your chest recognize laughter, which signals to the brain that you are in a good mood, which releases what some physicians call 'happy chemicals,'" he said.
The group practices the cell phone laugh, where they walk around and laugh as though talking on a phone. Another exercise is the lion laugh where participants stick out their tongues, and do a type of panting laugh. This is all done in an effort to relieve stress.
The laughter soon ceased as Shah brought the group down, to do some deep breathing exercises.
In addition to the therapeutic and stress relief benefits of laughter therapy, he said he is most struck by the community created from people laughing together.
"I was touched by how much it builds community where before people were feeling isolated and lacking resiliency," he said about learning laughter therapy in India.
"That sold me," Shah said. "I felt like I enjoyed the techniques I had learned and wanted to keep learning about them."
At the session's conclusion, participants, who an hour before sat next to each other in silence, were now asking about starting a club together in order to practice the techniques more.
"I like the community aspect of it," said Ananda Leeke, 41, a yoga instructor. "The energy of the group helps enormously, and we all looked so good laughing."
Gendry said laughing is the best medicine without a prescription.
"Laughter is a social glue that transcends all barriers: language, age, sex, social or racial background," Gendry said. "We see people who just want to laugh, people who are depressed, sad, believe they can't laugh anymore, in pain, with insomnia, introvert, stressed."