Dr. Lee S. Berg, a researcher at Loma Linda University’s Schools of Allied Health and Medicine, has studied repetitious or “mirthful” laughter since the 1980s. In a new study, he and his colleagues found that repetitive laughter caused the same hormonal stimulation as moderate physical exercise.
The Appetite Study
In this study, presented at the 2010 Experimental Biology conference in Anaheim, CA, fourteen healthy volunteers watched humorous or distressing videos over a period of three weeks. Each video was watched for twenty minutes. One group of randomly selected volunteers watched humorous videos, while the other group watched stressful videos for one week. Then no videos were watched for one week. After the second week, the group that had watched the humorous videos was asked to watch the stressful videos and the other group watched the humorous videos for another week. One of the stressful videos was Saving Private Ryan. The researchers took blood samples just before and right after the participants watched the videos. They analyzed the blood for levels of two hormones that regulate appetite, leptin and ghrelin. The researchers found no significant difference in leptin and ghrelin levels when the volunteers watched the stressful videos. However, leptin decreased and ghrelin increased when the participants watched the humorous videos.
The results suggest that the humorous videos increased appetite in the same way as physical exercise. “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. The value of the research is that it may provide for those who are health care providers with new insights and understandings, and thus further potential options for patients who cannot use physical activity to normalize or enhance their appetite,” says Berg as quoted in Science Daily.
Laughter is good Medicine
Many studies, including those of Berg and associates have looked at the health effects of laughter. Laughter clearly leads to psychological as well as physiological well-being. Mary Bennett and Cecile Lengacher have reviewed some of the evidence for the effect of laughter on muscle tension, cardiorespiratory functioning, and various other physiological measures. They conclude that the evidence shows that laughter leads to increased heart rate, respiratory rate, and oxygen consumption. This is followed by a period of relaxation, decrease in heart rate, decrease in respiratory rate and blood pressure. The effect of laughter on stress hormones, such as epinephrine (adrenalin) and cortisol is less clear and more studies are needed.
In a previous study, Lee Berg and Stanley Tan, looked at the effects of repetitive laughter on people with diabetes. They found that repetitive laughter raised good cholesterol (HDL) and lowered markers of inflammation. They suggested that repetitive or “mirthful” laughter be incorporated into diabetic care.
Laughter and positive emotions are clearly good for optimal health. The latest study by Berg and associates adds a “healthy” appetite to the list of benefits. People, who are depressed, sick, elderly, and who don’t exercise, may lose their normal appetite. “Laughter therapy” could help. Interestingly, the participants in the current study had the greatest change in their hormones, when they selected their humorous videos themselves.
Bennett, M.P. and Lengacher, C. Humor and Laughter May Influence Health: III. Laughter and Health Outcomes. Evid. Based Complement. Alternat. Med. (2008) 5: 37