Fitness junkies might want to put down their dumbbells and add some reps of side-splitting laughter to their exercise routines to boost overall health and wellness.

Employees at the University of Michigan Health System in Ann Arbor learned that laughter really is the best medicine when they tested a twist on traditional yoga known as laughter yoga. In these classes, belting out simulated belly laughs and school-girl giggles are as normal as stretching your body into a downward dog pose.

Similar classes are springing up across the country, combining the heart-healthy benefits of laughter with the soothing effects of deep breathing and stretching exercises.

Participants warm-up by chanting and clapping their hands, slowly moving on to more intense breathing and laughing exercises.

Laughter, along with a sense of humor, may even help prevent a heart attack, according to a 2005 University of Maryland Medical Center study. Researchers found that people with heart disease were forty percent less likely to laugh as compared with people of similar age.

The creation of laughter yoga is attributed to a physician from India who started the first laughing club in 1995. Advocates say this fusion of yoga and simulated laughter reduces stress, enhances the immune system, improves circulation and tones muscles.

Before you find a laughter yoga class near you, remember to leave clichéd jokes and tired punch lines at home. This form of yoga uses simulated laughter. No tricks or tickling are necessary.