In the three-week study to examine the effects that mirthful laughter and distress have on modulating the key hormones that control appetite, each subject was required to watch one 20-minute video at random that was either upsetting or humorous.
When the researchers compared the hormone levels pre- and post-viewing, they found that the volunteers who watched the distressing video showed no statistically significant change in their appetite hormone levels during the 20-minutes they spent watching the video.
In contrast, the subjects who watched the humorous video had changes in blood pressure and also changes in the leptin and ghrelin levels. Specifically, the level of leptin decreased as the level of ghrelin increased, much like the acute effect of moderate physical exercise that is often associated with increased appetite.
Berk explains, “The ultimate reality of this research is that laughter causes a wide variety of modulation and that the body’s response to repetitive laughter is similar to the effect of repetitive exercise.”
Repetitive laughter is similar to the effect of repetitive exercise. How great is that?