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Joyful laughter can impact your body’s hormones similarly to exercise—helping improve mood, decrease stress, boost your immune system, and impact appetite, according to new research presented this week at the Experimental Biology conference in Anaheim, California. Dr. Lee S. Berk, a long-time laughter researcher and a preventive care specialist at Loma Linda University’s medical school, set out to determine how laughter impacted two hormones that govern appetite—leptin and ghrelin. (When leptin decreases, appetite increases; when ghrelin goes up, appetite does too.)
To do this, Berk and colleagues recruited 14 participants for a three-week study. At the beginning of the study, participants underwent blood tests to determine hormone levels. A week later, they were randomly assigned to watch a 20-minute film clip intended to either evoke eustress (mirthful laughter) or distress. A week after that, they watched the type of film they hadn’t yet seen. For funny clips, participants were given a choice of work from several comedians; for the distressing clips, they watched a snippet of Saving Private Ryan. Before and after each viewing, researchers drew blood to test hormone levels. They also monitored blood pressure before and after.
Berk found little difference in appetite hormones when participants watched the distressing clip, but noted a significant difference among those who’d been watching comedy. In fact, researchers noted that leptin dropped and ghrelin went up in levels strikingly similar to those seen in people after exercise. The findings don’t suggest, Berk is careful to point out, that comedy is an appetite-booster. Instead, he says the research illustrates that repetitive laughter can impact the body much in the same way that repetitive exercise does. What’s particularly promising about this finding, Berk says, is that people struggling with lack of appetite who cannot exercise to help regulate their desire for food due to frailty or chronic pain, laughter could be the best medicine.