Laughter Affects Appetite Much Like a Workout Does
Study Finds Repetitive Laughter Has an Impact on Appetite Hormones
April 27, 2010 (Anaheim, Calif.) -- A hearty laugh and a moderate workout may have more in common than anyone thought.
Both affect the appetite hormones in much the same way, says Lee Berk, DrPH, MPH, director of the molecular research laboratory at Loma Linda University in Loma Linda, Calif., and a longtime researcher on the benefits of laughter.
''The parallel between moderate exercise and mirthful laughter is uncanny," Berk tells WebMD.
But he's clear from the start: "You can't increase leg muscle strength by sitting and laughing."
But he does think laughter, already linked with reducing stress and heart disease risk, as well as other benefits, may help improve appetite in those who have lost theirs due to disability or age. And it may improve wellness for the rest of us.
Laughter, Workout Link
In previous research, Berk has found that ''mirthful laughter'' reduces the stress hormones known as cortisol and catecholamines, much the same way that moderate physical exercise does.
It’s also been found to enhance immune system functioning and may lower cholesterol and blood pressure.
In the new study, Berk evaluated the effects of a good belly laugh on two hormones that regulate appetite: leptin and ghrelin.
"When leptin goes down, it increases appetite," Berk says. "When ghrelin goes up, it increases appetite.''
That is what typically happens after moderate exercise, he says.
To test the effects of exercise on these hormones, he showed 14 healthy volunteers, average age 21, 20-minute segments of two different videos.
One was humorous, and the participants selected one depending on their preference. Choices included videos with Bill Cosby, Jeff Foxworthy, Will Ferrell, and others.
He also showed them a video meant to be stressful to watch, the 1998 movie Saving Private Ryan, a graphic World War II movie.
The participants watched the videos in random order. They gave blood to assess their leptin and ghrelin levels a week before the study, immediately before viewing, and immediately after viewing the videos. The hormones were measured well before viewing, Berk says, to rule out the well-known anticipatory effect.