Psychological and physiological effects of laughter yoga sessions in Japan: A pilot study.

The purpose of this pilot study was to examine and evaluate the psychological and physiological effects of multiple sessions of laughter yoga on community members. Participants took part in a 45 min laughter yoga session once per month for 6 months. Before and after all sessions, participants completed the Profile of Mood States-Brief Japanese Version (J-POMS-B) questionnaire to assess their mood, and had blood drawn for the measurement of stress indicators and immune function. Serial changes in J-POMS-B scores were tested by three way analysis of variance, and changes in laboratory results per session were evaluated with a paired t-test. The results showed that repeated sessions of laughter yoga had psychologically beneficial effects, especially on the aspects of tension-anxiety, and vigor. Adrenocorticotropic hormone and cortisol values related to the participants' stress levels were significantly decreased after the fourth laughter yoga session. These results indicated that multiple laughter yoga sessions appeared to be effective in improving the psychological and physiological status of healthy adults.