The researchers concluded that laughing burned
about 1.3 calories per minute—about 10 to 20% more than in a calm
state. The benefit is akin to what you’d get doing some light indoor
gardening, while jogging burns about 10 calories per minute. Still,
based on that finding, 10 to 15 minutes of laughter a day could help
you drop as much as four pounds a year.

Laughter, says Marshall Brain, author of the How It Works books, has two physical components: gestures and the production of
sound. The brain signals the body to do both at the same time, and the
effects of hearty laughter can trickle all the way to the arm, leg and
trunk muscles. Some 15 facial muscles contract, and the zygomatic major
muscle lifts the upper lip.

Laughter,
Brain observes, triggers some physical activities that on the surface
don’t sound all that great. For instance, the respiratory system
becomes upset when the epiglotis closes the larynx halfway. Hearty
laughter activates the tear ducts and the face becomes moist and red in
the struggle for oxygen that ensues.

Citing
a study of laughter’s sonic structure, Brain notes that laughter can
trigger “ha-ha-ha” or “ho-ho-ho” sounds, but never a hybrid of the two.
That observation underscores the artifice of the “hee hee, ha ha, ho
ho” stew of chants practiced at the laughter therapy session at the
Philadelphia cancer hospital and among other laughter groups.

Nevertheless,
a growing number of proponents of laughter as medicine are embracing
the idea that harnessing self-driven laughter can yield tremendous
therapeutic benefits.

Laughter
enthusiasts trace the movement to Madan Kataria, MD, himself inspired
by Cousins. Kataria started a playful form of laughter yoga in Mumbai,
India, in 1995. Steve Wilson, a psychologist, met Kataria three years
later and picked up the torch, creating a training program (www.worldlaughtertour.com) through which therapists become Certified Laughter Leaders who direct sessions and laughter clubs.
Some 5,000 laughter clubs are organized in 40 countries, according to Kataria’s website, www.yogalaff.com.
Certified Laughter Leaders have been dispatched to help families of
military who have shipped out to Iraq or returned home with permanent
injuries. They’ve also helped train teachers to introduce laughter into
the classroom, hoping to develop more receptive students.