Researchers at Osaka University in Japan assigned 79 people between the ages of 40 and 74 to one of three groups. Thirty-two were assigned to a music group where they listened to music and sang with music therapists. Thirty participants participated in laughter yoga, which combines breathing exercises with laughter stimulated through playful eye contact, plus watched a traditional Japanese comedy show called Rakugo. Each session took place for one hour twice a week for three months. The remaining 17 were controls who neither listened to music nor participated in the laughter sessions.