According to a new study presented at the American Society of Hypertension 2008 Annual Meeting, laughter in the context of laughter yoga can significantly lower blood pressure and reduce cortisol, or stress hormone, levels.

Laughter yoga is a combination of laughter exercises, gentle yoga breathing, and stretching. The investigators of the study evaluated 200 people, both men and women, working in the information technology industry in India. These individuals participated in seven 20-30 minute laughter yoga sessions, where they alternated 45 seconds to one minute of laughter with deep breathing and stretching exercises. After three weeks, the investigators found that laughter yoga participants experienced significant reductions in their baseline blood pressures, as well as their cortisol levels. Participants also filled out questionnaires which showed that their perceived levels of stress were also lower.

According to Dr. Madan Kataria, the lead investigator of the study, laughter needs to be prolonged in order to bring about physiological and biochemical changes. And, you don't even need to feel happy while you laugh, as long as you laugh heartily for an extended period of time. There are 6000 laughter clubs in 60 countries where people practice laughter yoga, so perhaps there's one near you where you can laugh all the way to better health.