How many calories do I burn when I laugh?

Is her laughter a post-workout release or the workout itself? See more staying healthy pictures.

You've probably heard that laughter is good medicine, but that doesn't mean you'll be asking for a stand-up comedian after you break your arm (after all, good medicine is also good medicine). Laughter does have many positive measurable effects on your body, however. When we laugh, our bodies respond positively. There is a decrease in stress hormones (cortisol, adrenaline and dopac) and an increase in beta-endorphins (which lower feelings of depression) and human growth hormone (which helps protect us against disease and infection).

Incredibly, it's not only laughter that changes our body's chemistry -- the mere anticipation of laughing does, too (when you're driving to see a funny movie, for instance) [source: American Physiological Society]. In fact, your brain will respond to laughter even if the laughter is faked.

Laughter also prompts our bodies to produce more T-cells and globulins, which bolster our immune systems. And the type of positive mindset that enjoys a good laugh may keep you chuckling for years to come. People who report general feelings of happiness tend to be healthier overall and live longer than unhappy people.

But can we laugh ourselves into shape?

By lowering cortisol levels, we may be shedding belly fat as well, or at least issuing fewer orders to store a protective spare tire around our central organs. Cortisol is a dieter's nightmare -- it prompts us to eat (stress eating, anyone?), lowers our post-meal metabolism and then stashes the fat in our midsection. People who are otherwise skinny but who have extra belly fat have measurably higher levels of cortisol, so laughing may help you finish the job that your diet started.

So how many calories get burned when we laugh? Can we chortle ourselves into a smaller pants size?