Scientifc Studies: Positive Healing of Laughter
New Medical Study:Laughter Lowers Blood Pressure
According to a new study presented at the American Society of Hypertension 2008 Annual Meeting, laughter in the context of laughter yoga can significantly lower blood pressure and reduce cortisol, or stress hormone, levels. Laughter yoga is a combination of laughter exercises, gentle yoga breathing, and stretching. The investigators of the study evaluated 200 people, both men and women, working in the information technology industry in India. These individuals participated in seven 20-30 minute laughter yoga sessions, where they alternated 45 seconds to one minute of laughter with deep breathing and stretching exercises.
After three weeks, the investigators found that laughter yoga participants experienced significant reductions in their baseline blood pressures, as well as their cortisol levels. Participants also filled out questionnaires which showed that their perceived levels of stress were also lower.
According to Dr. Madan Kataria, the lead investigator of the study, laughter needs to be prolonged in order to bring about physiological and biochemical changes. And, you don't even need to feel happy while you laugh, as long as you laugh heartily for an extended period of time. There are 6000 laughter clubs in 60 countries where people practice laughter yoga, so perhaps there's one near you where you can laugh all the way to better health.
Source
Adapted from Heartwire -- a professional news service of WebMD Chaya MS, Kataria M, Nagendra R, et al. The effects of hearty extended unconditional (HEU) laughter using laughter yoga techniques on physiological, psychological, and immunological parameters in the workplace: a randomized control trial. American Society of Hypertension 2008 Annual Meeting; May 14, 2008; New Orleans, LA.
Article on Laughter 2006 USA
Fairleigh Dickinson University in Teaneck, New Jersey. Prof. Charles Schaefer URL PDF
Even fake laughter is good medicine
Psychologists say a minute of forced laughter can help the blues, writes Richard Morin in Washington.
April 1 2003
The news is grim these days, so we all could use a good laugh, even a fake one, says a psychologist who claims that a minute of forced laughter can chase away the blues.
"Forced laughter is a powerful, readily available and cost-free way for many adults to regularly boost their mood and psychological wellbeing," said Charles Schaefer, psychology professor at Fairleigh Dickinson University in Teaneck, New Jersey.
Professor Schaefer also found that self-imposed smiling is a mood enhancer. But howling like a wolf for a minute didn't do anything - except make a racket, Professor Schaefer and his research colleagues reported in two separate studies in Psychological Reports.
His findings come from two experiments he conducted on 39 college students and Teaneck residents. While additional studies with larger samples are needed to bolster his conclusions, Professor Schaefer said, these initial results are important enough to warrant attention.
Professor Schaefer said he uncovered the salubrious effect of artificial laughter in a study of 17 Fairleigh Dickinson students. He first asked them questions that measured their mood. Then he directed them to laugh heartily for a minute, and tested them again. On average, test subjects reported feeling significantly better after 60 seconds of fake merriment.
Why would phony laughter work? Because your body doesn't know it's fake, even though your brain might, Professor Schaefer said. "Once the brain signals the body to laugh, the body doesn't care why. It's going to release endorphins, it's going to relieve stress as a natural physiological response to the physical act of laughing."
Intrigued, Professor Schaefer designed a second study to compare the effects of forced laughter with continuous smiling or howling.
He directed 22 study participants to smile broadly for 60 seconds, laugh heartily for 60 seconds and howl for 60 seconds. Laughing and smiling both helped boost their spirits, but howling didn't, he found. Forced laughter was the best medicine. "One minute of forced laughing showed a significantly greater improvement than one minute of smiling," Professor Schaefer said.
How did test subjects know exactly what to do?
"My research assistant and I would demonstrate," Professor Schaefer said.
"We stood before them and laughed hysterically and then howled. I instructed them to imagine a wolf howling at the moon. When they saw a senior professor howling, it took away some of their natural self-consciousness."
- Washington Post
UNIVERSITY OF MARYLAND SCHOOL OF MEDICINE STUDY SHOWS
LAUGHTER HELPS BLOOD VESSELS FUNCTION BETTER
Volunteers were shown funny and disturbing movies to test the effect of emotions on
blood vessels
Using laughter-provoking movies to gauge the effect of emotions on
cardiovascular health, researchers at the University of Maryland
School of Medicine in Baltimore have shown for the first time that
laughter is linked to healthy function of blood vessels. Laughter
appears to cause the tissue that forms the inner lining of blood
vessels, the endothelium, to dilate or expand in order to increase
blood flow.
When the same group of study volunteers was shown a movie that
produced mental stress, their blood vessel lining developed a
potentially unhealthy response called vasoconstriction, reducing
blood flow. That finding confirms previous studies, which suggested there was a link
between mental stress and the narrowing of blood vessels.
The results of the study, conducted at the University of
Maryland Medical Center, were presented at the Scientific
Session of the American College of Cardiology on March 7,
2005, in Orlando, Florida.
The endothelium has a powerful effect on blood vessel
tone and regulates blood flow, adjusts coagulation and
blood thickening, and secretes chemicals and other
substances in response to wounds, infections or irritation. It
also plays an important role in the development of
cardiovascular disease.
“The endothelium is the first line in the development of
atherosclerosis or hardening of the arteries, so, given the
results of our study, it is conceivable that laughing may be
important to maintain a healthy endothelium, and reduce
the risk of cardiovascular disease,” says principal investigator
Michael Miller, M.D., director of preventive cardiology at
the University of Maryland Medical Center and associate
professor of medicine at the University of Maryland School
of Medicine. “At the very least, laughter offsets the impact
of mental stress, which is harmful to the endothelium.”
The study included a group of 20 non-smoking, healthy
volunteers, equally divided between men and women,
whose average age was 33. The participants had normal
blood pressure, cholesterol and blood glucose levels. Each
volunteer was shown part of two movies at the extreme ends of the emotional spectrum.
They were randomized to first watch either a movie that would cause mental stress, such as
the opening scene of “Saving Private Ryan” (DreamWorks, 1998), or a segment of a movie
that would cause laughter, such as “King Pin” (MGM, 1996). A minimum of 48 hours later,
they were shown a movie intended to produce the opposite emotional extreme.
Prior to seeing a movie, the volunteers fasted overnight and were given a baseline blood
vessel reactivity test to measure what is known as flow-mediated vasodilation. For that test,
blood flow in the brachial artery in the arm was restricted by a blood pressure cuff and
released. An ultrasound device then measured how well the blood vessel responded to the
sudden increase in flow.
Volunteers watched a 15-minute segment of the movie while lying down in a
temperature-controlled room. After the movie was shown, the brachial artery was
constricted for five minutes and then released. Again, ultrasound images were acquired.
Changes in blood vessel reactivity after the volunteers watched a movie lasted for at least
30 to 45 minutes. A total of 160 blood vessel measurements were performed before and
after the laughter and mental stress phases of the study.
There were no differences in the baseline measurements of blood vessel dilation in either
the mental stress or laughter phases. But there were striking contrasts after the movies were
seen. Brachial artery flow was reduced in 14 of the 20 volunteers following the movie clips
that caused mental stress. In contrast, beneficial blood vessel relaxation or vasodilation
was increased in 19 of the 20 volunteers after they watched the movie segments that
generated laughter. Overall, average blood flow increased 22 percent during laughter,
and decreased 35 percent during mental stress.
Several volunteers had already seen “Saving Private Ryan,” says Dr. Miller, but even so,
some of them were among the 14 with reduced blood flow.
“The magnitude of change we saw in the endothelium is similar to the benefit we might
see with aerobic activity, but without the aches, pains and muscle tension associated with
exercise,” says Dr. Miller. “We don’t recommend that you laugh and not exercise, but we do
recommend that you try to laugh on a regular basis. Thirty minutes of exercise three times
a week, and 15 minutes of laughter on a daily basis is probably good for the vascular
system.”
Dr. Miller says this study was not able to determine the source of laughter’s benefit. “Does it
come from the movement of the diaphragm muscles as you chuckle or guffaw, or does it
come from a chemical release triggered by laughter, such as endorphins?” he asks. Dr.
Miller says a compound called nitric oxide is known to play a role in the dilation of the
endothelium. “Perhaps mental stress leads to a breakdown in nitric oxide or inhibits a
stimulus to produce nitric oxide that results in vasoconstriction,” says Dr. Miller.
The current study builds on earlier research Dr. Miller conducted on the potential benefits
of laughter, reported in 2000, which suggested that laughter may be good for the heart. In
that study, answers to questionnaires helped determine whether people were prone to
laughter and ascertain their levels of hostility and anger. Three hundred volunteers
participated in the study. Half of them had suffered a heart attack or had undergone
coronary artery bypass surgery; the other half did not have heart disease. People with heart
disease responded with less humor to everyday life situations than those with a normal
cardiovascular system.
Dr. Miller says certain factors in the earlier study may have affected the results. For
example, he says it may be that people who have already had a coronary event are not as
laughter-prone as those who do not have heart disease.
He says the current study sought to eliminate that uncertainty by using volunteers whose
cardiovascular system was healthy. The results of the brachial artery blood flow
measurements, which are precise and objective, appear to make the connection between
laughter and cardiovascular health even stronger, according to Dr. Miller.
Other researchers in the study included Charles Mangano, R.D.M.S; Young Park, M.D.;
Radha Goel, M.D.; Gary Plotnick, M.D. and Robert A. Vogel, M.D., all from the University
of Maryland School of Medicine. The study was supported by a grant from the National
Institutes of Health and a Veterans Affairs Merit award to Dr. Miller.
Maybe Laughter Really Is The Best Medicine, And It’s Prophylactic!
There’s no doubt that laughter feels good, but is there real neurophysiology behind it and what can you do about it? In a paper being presented in an American Physiological Society session at Experimental Biology 2006, Lee S. Berk of Loma Linda University, reports that not only is there real science and psychophysiology, but just the anticipation of the “mirthful laughter” involved in watching your favorite funny movie has some very surprising and significant neuroendocrine/hormone effects. According to Berk: “The blood drawn from experimental subjects just before they watched the video had 27% more beta-endorphins and 87% more human growth hormone, compared to blood from the control group, which didn’t anticipate the watching of a humorous video. Between blood pulls, the control group stayed in a waiting room and could choose from a wide variety of magazines,” he explained. *Paper presentation: “Beta-Endorphin and HGH increase are associated with both the anticipation and experience of mirthful laughter,” 12:30 p.m.- 3 p.m. Sunday April 2, APS Behavioral neuroscience & drug abuse Section abstract 233.18/board #C706. Research was by Lee S. Berk, Department of Health Promotion and Education, School of Public Health and Department of Pathology, School of Medicine, Loma Linda University; Stanley A. Tan, Oakcrest Health Research Institute, Yucaipa; and James Westengard, Dept. of Pathology, School of Medicine; Berk is associated with all three institutions. HGH, endorphin difference is long-lasting; setting the baseline and environment is key Berk said that the strong difference between the two groups in terms of human growth hormone (HGH) and beta-endorphin blood levels was maintained from just prior to the beginning of video watching, throughout the hour of viewing and afterwards, also.
Scientific studies on Laughter benefits:
Laughter and Health
¬We've ¬long known that the ability to laugh is helpful to those coping with major illness and the stress of life's problems. But researchers are now saying
laughter can do a lot more --
it can basically bring balance to all the components of the immune system, which helps us fight off diseases.
Laughter reduces levels of certain stress hormones. In doing this, laughter provides a safety valve that shuts off the flow of stress hormones and the fight-or-flight compounds that swing into action in our bodies when we experience stress, anger or hostility. These stress hormones suppress the immune system, increase the number of blood platelets (which can cause obstructions in arteries) and raise blood pressure. When we're laughing, natural killer cells that destroy tumors and viruses increase, as do Gamma-interferon (a disease-fighting protein), T-cells, which are a major part of the immune response, and B-cells, which make disease-destroying antibodies.
Laughter may lead to hiccupping and coughing, which clears the respiratory tract by dislodging mucous plugs. Laughter also increases the concentration of salivary immunoglobulin A, which defends against infectious organisms entering through the respiratory tract.
What may surprise you even more is the fact that researchers estimate that laughing 100 times is equal to 10 minutes on the rowing machine or 15 minutes on an exercise bike. (More recent research has shown even more.) Laughing can be a total body workout! Blood pressure is lowered, and there is an increase in vascular blood flow and in oxygenation of the blood, which further assists healing. Laughter also gives your diaphragm and abdominal, respiratory, facial, leg and back muscles a workout. That's why you often feel exhausted after a long bout of laughter -- you've just had an aerobic workout!
The psychological benefits of humor are quite amazing, according to doctors and nurses who are members of the American Association for Therapeutic Humor. People often store negative emotions, such as anger, sadness and fear, rather than expressing them. Laughter provides a way for these emotions to be harmlessly released. Laughter is cathartic. That's why some people who are upset or stressed out go to a funny movie or a comedy club, so they can laugh the negative emotions away (these negative emotions, when held inside, can cause biochemical changes that can affect our bodies).
• Increasingly, mental health professionals are suggesting "laughter therapy," which teaches people how to laugh -- openly -- at things that aren't usually funny and to cope in difficult situations by using humor. Following the lead of real-life funny-doc Patch Adams (portrayed by Robin Williams in a movie by the same name), doctors and psychiatrists are becoming more aware of the therapeutic benefits of laughter and humor. This is due, in part; to the growing body of humor and laughter scholarship (500 academicians from different disciplines belong to the International Society for Humor Studies). HowStuffWorks, Inc. Discovery Communications, LLC
Laughter Yoga is an acknowledged form of getting your laughing and childlike playfulness.
Laughter Studies sampling below:
(There are many more)
1.
Oxford Journals
Evidence-based Complementary and Alternative Medicine
• Oxford Journals
• Medicine
• Evidence-based Compl. and Alt. Medicine
• Volume 3, Number 1
• Pp. 61-63
eCAM Advance Access originally published online on January 16, 2006
eCAM 2006 3(1):61-63; doi:10.1093/ecam/nek015
________________________________________Review
Humor and Laughter may Influence Health. I. History and Background
Mary Payne Bennett1 and Cecile A. Lengacher2
1Indiana State University College of Nursing IN, USA, and 2University of South Florida College of Nursing FL, USA
Can Humor and Laughter...
Stress, Psychoneuroimmunological...
References
Articles in both the lay and professional literature have extolled the virtues of humor. The concept that humor or laughter can be therapeutic goes back to biblical times Current research indicates that using humor is well accepted by the public and is frequently used as a coping mechanism.
Can Humor and Laughter Influence Health Outcomes?
History
Using humor to decrease stress, diminish pain, improve quality of life and even attempt to improve immune functioning has recently become a popular topic in the lay and professional literature (1–4). Laughter in response to a humorous stimulus is a natural occurrence and does not require large amounts of time or money in order to implement. While therapies such as relaxation and exercise require significant time and commitment, and therapies such as herbs or massage can be expensive, use of humor can be easily implemented and cost effective. However, clinical benefits must still be documented.
controlled studies have been identified that document the effects of laughter on clinical health outcomes.
So what do we really know about the role of sense of humor, use of humor by patients with various illnesses, or the effects of laughter on various health related outcomes? Is use of humor an approach that we should implement in our practices and/or recommend to our patients? This is the first of the four articles that reviews, clarifies and synthesizes the professional literature concerning humor and health outcomes. This first paper presents basic background on the theoretical underpinnings concerning how the mind can affect the body, such as the effects of stress on immune functioning. Research in this area provides fundamental support for the supposition that interventions that lower stress may also help improve physiological outcomes. The second paper reports studies that document patient interest in and use of humor as a complementary therapy, and provides evidence to support that humor may be one of the more frequently used complementary therapies. The third paper describes studies that report the relationship between sense of humor and various health outcomes. The final paper examines either the effect of a humorous stimulus and/or effects of laughter on health outcomes. These latter two parameters are difficult to separate, since patients who are exposed to a humorous stimulus usually respond with laughter, however, not all studies separately document laughter and exposure to a humorous stimulus.
This review is based on a search of Pub-Med and PsychINFO, using the search terms humor and laughter, plus bibliographic review for older articles that may not be documented in the databases. A search using those terms produced 324 hits, from which 55 relevant articles were obtained. Only original empirical research reporting the psychological or physiological effects of humor or laughter are reported here, with the main focus on research documenting health related outcomes. Owing to small sample sizes in most studies and the limited number of available reviews, sample size was not used as a determinant to exclude certain analyses from our review. A meta-analysis was not possible owing to the use of multiple measures of sense of humor and various outcomes utilized in the studies reviewed.
Definitions
A full discourse on humor theory is beyond the scope of this review, but certain basic definitions are essential. From a psychological perspective, humor involves cognitive, emotional, behavioral, psycho-physiological and social aspects (18). The term humor can refer to a stimulus, which is intended to produce a humorous response (such as a humorous video), a mental process (perception of amusing incongruities) or a response (laughter, exhilaration). Laughter is the most common expression of humorous experience. Humor and laughter are also typically associated with a pleasant emotional state (18). For the purpose of these reviews, humor is defined as a stimulus that helps people laugh and feel happy. Laughter is a psycho-physiological response to humor that involves both characteristic physiological reactions and positive psychological shifts. Sense of humor is a psychological trait that varies considerably and allows persons to respond to different types of humorous stimuli. It is necessary to differentiate between these variables, as some analyses of humor use a humor stimulus (such as a video) to determine the effect of ‘humor’ on an outcome, while others look specifically at the effects of laughter on these outcomes. Still others analyze various ways to measure sense of humor, in an attempt to determine whether scoring higher on a sense of humor instrument is related to various health related outcomes.
Stress, Psychoneuroimmunological Reactions and Health
Can Humor and Laughter...
Stress, Psychoneuroimmunological...
References
Theoretical Framework and Early Experiments
What is the underlying theoretical framework that helps explain why use of a complementary therapy, such as humor, may affect health? It may be that these therapies work by reducing the effects of stress. Interest in the influence of psychological factors on susceptibility to certain disease states goes back to the times of Galen (19), when it was noted that persons who developed cancer often had a ‘melancholic’ personality. Since then, numerous clinicians have shared anecdotal data concerning the development of cancer or other diseases in persons with certain psychological styles, or after a stressful life event, such as bereavement (20).
Selye's work was one of the first to document the general effects of stress on the sympathetic nervous system, endocrine system and lymphatic organs (21). Further studies established that activation of the stress response could also be triggered by acute emotions, physical exertion, cold and pain (22). Later, Lazarus and Folkman (23) broadened the definition of stress from Selye's concept of ‘environmental demands’ to include psychological components such as appraisal and coping. While Lazarus and Folkman's theory helped to explain the moderation of stressors using coping mechanisms, it did not attempt to explain the possible consequences of these coping mechanisms in terms of physiological effects on immune functioning. The field of PNI brings all of these factors together in a testable theoretical framework. PNI started from a multi-factorial model of illness, which included stress, coping and disease formation (24). This theory was further developed by Solomon (1987) to include the impact of stress on the immune system in disease formation (25). Later, the term ‘psychoneuroimmunology’ was coined by Ader and Cohen (26) to describe the basic phenomena of this theory: interactions between the nervous system and the immune system, and the subsequent effects of these interactions upon disease development/progression.
PNI and Stress
PNI researchers have repeatedly documented that increased stress levels can lead to changes in psychological and physiological functioning. In addition to changes in the usual stress hormones such as ACTH, cortisol, epinephrine and norepinephrine, many other messengers are influenced by exposure to stressors. Production and release of prolactin, growth hormone, insulin, glucagon, thyroid hormone and gonadotrophin can be affected by physical and emotional stress (27). Levels of neurotransmitters, neurohormones, cytokines and various cells in the immune system can also be affected by stress (28).
A Neurological Approach to Laughter
Ideally, we would be able to draw a flow chart that outlines all of the neurological processes involved in the effects of laughter on stress and immune functioning. But unfortunately, the state of the science is not to that level at this time. We really know very little about how the brain functions in response to a humorous stimulus. According to Curtis (27), speech and laughter are both uniquely human. But while there is considerable information on the neuronal representation of speech, little is known about brain mechanisms of laughter. We do have some evidence that the supplementary motor area of the brain is involved in this response. Curtis reports that ‘electrical stimulation in the anterior part of the human supplementary motor area (SMA) can elicit laughter’ (29). Moreover, it has been proposed by Tanji (30) and Picard and Stick (31) that the anterior part of the SMA is part of a further development in humans to accommodate the specialized functions of speech, manual dexterity and laughter. This area might correspond to the pre-supplementary motor area, a region situated anterior to the SMA proper, recently described in non-human primates, and thought to be involved in high-level motor programming (30,31). Finally, Fried and Wilson (32) have examined putative regions in the brain using electric current that stimulates laughter. The data suggest that this is at least one anatomical location for the neurological response to humorous stimuli. However, more research is needed to determine how these neurological changes subsequently affect the physiological response to stressors, and possibly improve immune functioning.
Footnotes
Can Humor and Laughter...
Stress, Psychoneuroimmunological...
References
1. Balick M and Lee R. The role of laughter in traditional medicine and its relevance to the clinical setting: Healing with ha! Altern Ther Health Med 2003; 9: 88–91[Medline]
2. Bennett H. Humor in medicine South Med J 2003; 96: 1257–61[Medline]
3. MacDonald C. A chuckle a day keeps the doctor away: therapeutic humor and laughter J Psychosoc Nurs Ment Health Serv 2004; 42: 18–25[Medline]
4. Weiss R. Initiative proves laughter is the best medicine Health Prog 2002; 83: 54[Medline]
5. Cousins N. Anatomy of an Illness as Perceived By the Patient 1979;Toronto Bantam
6. Fry W. Mirth and oxygen saturation levels of peripheral blood Psychother and Psychosom 1971; 19: 76–84
7. Fry W. The respiratory components of mirthful laughter J Biol Psychol 1977; 19: 39–50
8. Fry W. Humor, physiology, and the aging process In Nahemov L, McCluskey-Fawcett K, McGhee P (Eds.). Humor and Aging 1986;Orlando, Florida Academic Press pp. 81–98
9. Fry W and Savin W. Mirthful laughter and blood pressure Humor: Int J Humor Res 1988; 1: 49–62
10. Fry W. The physiological effects of humor, mirth, and laughter J Am Med Assoc 1992; 267: 1857–8[CrossRef][Medline]
11. Fry W. The biology of humor Humor: Int J Humor Res 1994; 7: 111–26
12. Berk L, Tan S, Nehlsen-Cannarella S, Napier B, Lewis J, Lee J, et al. Humor associated laughter decreases cortisol and increases spontaneous lymphocyte blastogenesis Clin Res 1988; 36: 435A
13. Berk L, Tan S, Napier B, Evy W. Eustress of mirthful laughter modifies natural killer cell activity Clin Res 1989; 37: 115A
14. Berk L, Tan S, Fry W, Napier B, Lee J, Hubbard R, et al. Neuroendocrine and stress hormone changes during mirthful laughter Am J Med Sci 1989; 298: 391–6
15. Berk L, Tan S, Fry W. Eustress of Humor associated laughter modulates specific immune system components Annals of Behavioral Medicine Supplement, Proceedings of the Society of Behavioral Medicine's 16th Annual Scientific Sessions 1993; 15: pp. S111
16. Berk L and Tan S. Eustress of mirthful laughter modulates the immune system lmyphokine interferon-gama Annals of Behavioral Medicine Supplement, Proceedings of the Society of Behavioral Medicine's 16th Annual Scientific Sessions 1995; 17: pp. C064
17. Berk L, Felten D, Tan S, Bittman S, Westengard J. Modulation of neuroimmune parameters during the eustress of humor-associated mirthful laughter Altern Ther Health Med 2001; 7: 62–72 74–6[ISI][Medline]
18. Martin R. Humor, laughter, and physical health: methodological issues and research findings Psychol Bull 2001; 127: 504–19[CrossRef][ISI][Medline]
19. Chiappelli F, Prolo P, Cajulis OS. Evidence-based research in complementary and alternative medicine I: History Evid Based Complement Alternat Med 2005; 2: 453–8[Abstract/Free Full Text]
20. Locke S and Kraus L. Modulation of natural killer cell activity by life stress and coping ability In Levy S (Ed.). Biological Mediators of Behavior and Disease: Neoplasia 1982;New York Elsevier pp. 3–28
21. Seyle H. The general adaptation syndrome and the diseases of adaptation J Clin Endocrinol Metab 1946; 6: 117–230
22. Cannon W. Bodily Changes in Pain, Hunger, Fear and Rage 1946;Boston Charles T. Branford
23. Lazarus R and Folkman S. Stress, Appraisal, and Coping 1984;New York Springer
24. Engel G. Psychological Development in Health and Disease 1962;Philadelphia Saunders
25. Soloman G. Psychoneuroimmunoloic approaches to research on AIDS Ann N Y Acad Sci 1987; 494: 928–36
26. Ader R and Cohen N. Conditioned immunopharmacologic responses In Ader R (Ed.). Psychoneuroimmunology New York Academic Press pp. 6–38
27. Curtis G. Psychoendocrine stress response: Steroid and peptide hormones In Stoll BA (Ed.). Mind and Cancer Prognosis 1979;Chichester John Wiley & Sons pp. 61–72
28. Anderson G, Kiecolt-Glaser J, Glaser R. A biobehavioral model of cancer stress and disease course Am Psychol 1994; 49: 389–404[CrossRef][Medline]
29. Fox PT, Ingham RJ, Ingham JC, Hirsch TB, Downs H, Martin C, et al. A PET study of the neural systems of stuttering 158 Nature 1996; 382: 158–61[CrossRef][Medline]
30. Tanji J. New concepts of the supplementary motor area Curr Opin Neurobiol 1996; 6: 782–7[CrossRef][ISI][Medline]
31. Picard N and Strick PL. Motor areas of the medial wall: a review of their location and functional activation Cereb Cortex 1996; 6: 342–53[Abstract/Free Full Text]
32. Fried I and Wilson CL. Electric current stimulates laughter Nature 1998; 391: 650[CrossRef][Medline]
Received March 30, 2005; accepted December 29, 2005
M. P. Bennett and C. Lengacher
Humor and Laughter May Influence Health: III. Laughter and Health Outcomes
Evid. Based Complement. Altern. Med., March 1, 2008; 5(1): 37 - 40.
________________________________________
M. P. Bennett and C. Lengacher
Humor and Laughter May Influence Health IV. Humor and Immune Function
Evid. Based Complement. Altern. Med., December 5, 2007; (2007) nem149v1.
________________________________________
M. P. Bennett and C. Lengacher
Humor and Laughter May Influence Health: II. Complementary Therapies and Humor in a Clinical Population
Evid. Based Complement. Altern. Med., June 1, 2006; 3(2): 187 - 190.
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2.
Article on Laughter 2003 USA Tammie S. Diggs URL --
Laughter: Is It Healthy?
In a nation that spent some 75 million dollars on prescription drugs in 1993, not to mention illegal drugs, we sometimes overlook the coping mechanisms we have been endowed with (U.S. 1995). Our bodies were created to take care of themselves for the most part, and we sometimes botch things up when we try to alter our system with drugs. In Proverbs 17:22 (1989), it says "A merry heart doeth good like a medicine, but a broken spirit drieth the bones." For many years scientists and lay persons have done studies, research, and performed experiments concerning the effects of laughter on one's physical and mental health. These studies have proven that when we laugh, there is an actual chemical change in our bodies that helps to ease pain and release stress. Laughter is a coping mechanism for the normal stress of life.
There are two kinds of stress--distress, which is the negative kind of stress; and eustress, which is the positive kind of stress. While distress increases stress hormones such as beta-endorphin, corticotrophin, cortisol, growth hormone, prolactin, and the catecholamines, eustress decreases these hormones and instead increases the activity of Natural Killer (NK) cells that help fight diseases (Berk & Tan 1996). Distressful events and major life changes can obviously impact our bodies negatively. It has been proven that stress depletes the immune system's ability to fight against disease. Dr. Lee Berk and Dr. Stanley Tan of the Loma Linda University Medical Center have done an abundance of research in psychoneuroimmunology (PNI). PNI simply says that the immune system is directly connected to the brain; therefore, it would be effected by the emotions. One of Berk and Tan's experiments showed that immunosuppressive hormones (hormones that harm or deplete the immune system) such as epinephrine and cortisol were lower in those participants that laughed than in those who did not (Wooten 1995). Another experiment performed by Berk and Tan (1996) in which they presented their results at a conference on April 18, 1996, proved that laughing (while watching a humorous video) increases the amount of NK cells.
Indirectly, stress is probably our number one killer. It effects us physically and mentally, wearing our immune systems down, and causing us to be more susceptible to sickness and disease. We try to treat the disease, when we really need to treat the cause. How does one treat something like stress? Many times the stressors cannot be removed from a person's life; they are permanent fixtures. Laughter, if used generously, can help drain the stress away. As Mark Twain once said, "The human race has only one really effective weapon, and that's laughter. The moment it arises, all our hardnesses yield, all our irritations and resentments slip away, and a sunny spirit takes their place."
What is laughter? Laughter is a form of eustress that releases those bad and distressful emotions that cause harmful chemical effects on the body (Berk & Tan 1996). Laughter is like an exercise; that is why your stomach sometimes feels sore after a good belly laugh. Just as in exercise, there are two stages to laughter: the arousal phase--when the heart rate increases--and the resolution phase--when the heart rests. A person's heart can reach up to 120 beats per minute (bpm) when laughing. Laughing can lower your blood pressure, increase vascular flow, and boost the immune system. It gives the diaphragm, abdominal, intercostals, respiratory accessory, and facial muscles a complete workout. Some people, depending on how they laugh, may even use their arm, leg, and back muscles when laughing. Laughter also releases endorphins in the brain; these are our bodies' natural pain killers (Wooten 1995). Endorphins are neurotransmitters that attach to the same receptors in our brains as the opiates. Opiate drugs not only cause us to lose touch with reality, but they also numb pain. When we laugh, it releases the endorphins in our brain; thus, laughing is like taking opium or morphine without the adverse side effects (Kalat 1995).
In Berk and Tan's (1996) experiment concerning the laughter immune connection, they used ten healthy fasting males who volunteered for the experiment, and had them view a one hour, funny video. They took blood samples of their interferon-gamma (IFN) before, during, and after they watched the tape. They had significant results that showed increased activity in IFN after watching the funny video and on into the following day. What is IFN? It activates the T cells, B cells, immunoglobulins, and NK cells; it helps to fight viruses, and regulate cell growth. This could be very important in the research for cancer since it also fights against tumorous cells.
Nearly 2000 years ago, the physician Galen stated that cheerful women were less likely to get cancer than those women who were depressed (Simonton 1978). John Steinbeck once said "A sad soul can kill you quicker, far quicker, than a germ." Laughter's ability to be a pain reliever and its ability to fight tumorous cells have added an exciting new area of research to cancer. Some of the research done by O. Carl Simonton, M.D. and Stephanie Matthews-Simonton (1978), leads us to believe that a person's emotional status does indeed effect their likelihood of getting or overcoming cancer. Perhaps, if people would start relieving their stress through laughter before they get cancer, there might be a reduction in the number of cancer patients altogether.
Norman Cousins (1979), the man who started the laughter health craze in this century, was editor of the Saturday Review for over thirty years, and has written numerous books including Anatomy of an Illness. In August 1964, Cousins came home from a meeting in Moscow with a fever and feeling achy all over. Within a week he could not move and his sedimentation rate was up to 88. The sedimentation rate relates to how much infection is in the body and a sed. rate of 60 to 70 is thought to be very high. He was eventually diagnosed with ankylosing spondylitis, which is a collagen illness that attacks the connective tissues of the body. He once said it felt as if he was being pulled apart at the joints. The doctors told him it was probably caused from exposure to heavy-metal poisoning, so he began to think of when he could have been exposed. The only thing he could remember was that his hotel in Moscow was next to a major highway where diesel trucks passed all night long, and since there was no air in the room, he had kept the windows open all the time. However, his wife was with him, and she did not become sick. He started reading material about stress and how it can wear down your immune system. He came across a book by Hans Selye called The Stress of Life that proposed the theory that negative emotions cause stressful and harmful effects on the body. He hypothesized that if the bad emotions do harmful things, then the good emotions should be helpful or healthful.
At the time the hospital was mostly trying to keep Cousins out of pain since there was no cure or treatment for his disease. He was being given the maximum amount of aspirins (26) and phenylbutazone (12) every day, along with sleeping pills and codeine. Realizing that that amount of medicine was very toxic, he decided to try laughter. He moved home and hired a nurse to oversee his medical treatment. His nurse would also show him Marx Brothers films and read humorous stories and books to him. Within days he was off of all pain killers and sleeping pills and discovered that ten minutes of genuine belly laughter gave him two hours of pain-free sleep. He wrote an article in the New England Journal of Medicine about his findings in laughter and was greatly criticized. He never once claimed that laughter had been the only factor in his healing process, but said that it had aided in his recovery by relieving pain. Despite the criticism, he stood by his claims, and was finally vindicated in January 27, 1989, when the Journal of the American Medical Association published an article entitled "Laugh If This Is a Joke." Lars Ljungdahl, the Swedish researcher (1989) who wrote that article concluded that "a humor therapy program can increase the quality of life for patients with chronic problems and that laughter has an immediate symptom-relieving effect for these patients, an effect that is potentiated when laughter is induced regularly over a period".
Gelkopf, Kreitler, and Sigal (1993) researched the effects of humor on hospitalized schizophrenic patients. Although they did not have any negative findings (mostly no change at all), they did have positive results from six out of twenty-one variables. They took thirty-four similar schizophrenic patients from two different hospital wards and showed each group seventy videos within one month's time. The control group saw all different kinds of videos and the experimental group only watched humorous videos. There was no change in their health, but there was a significant change in their aggressive behavior. They were observed to have less "verbal hostility" and fewer psychiatric symptoms such as depression and anxious tendencies. Gelkopf and his colleagues (1993) state that one of the reasons schizophrenic patients may not be as receptive to humor as other people without schizophrenia, may be because it requires certain cognitive processes to appreciate humor. Since those with schizophrenia have ailing minds, they may be unable to recognize humor. Regardless, if humorous videos help to lower aggressive behavior and depressive tendencies, then it could still be useful.
Not only are psychologists and PNI researchers preaching about the positive effects of laughter, but even medical doctors have recognized its potential. Dr. Patch Adams of Hillsboro, West Virginia, who is the physician for Gesundheit Institute, a forty bed hospital, says to work at his hospital you must ". . .look funny and . . . be funny." Joel Goodman, a humor consultant who is in charge of the Humor Project has been contacted by numerous hospitals wanting to launch a humor program for their patients. These programs use such things as humor rooms, comedy carts, and Clown Care Units. Dr. John M. Driscoll, Jr. from Columbia-Presbyterian Medical Center in New York City believes that there will be shorter hospital stays due to the new humor programs that have been started. As Goodman says "like chicken soup, it couldn't hurt" (Finnerty 1995).
On average children laugh 400 times per day, and adults only laugh 15 times per day. So if laughter is so good, why are we not doing more of it? Maybe there should be a laughing room added to the many health clubs in our nation. Although this might sound crazy, laughing clubs have already been started. Madan Kataria in Bombay, India started the first of the Laughing Clubs International in March of 1995. In a years time eighty clubs had spread throughout India, and Kataria hopes other countries will follow their lead. The members of these clubs generally gather in the park in the morning before work. They raise their arms in the air, to erase inhibitions, and start with Ho-ho, ha- ha, Silent laughter with mouth closed, and then Silent laughter with mouth open. Some of the laughing clubs also incorporate jogging with their laughing. When asked why they did not just tell jokes to laugh he replied "at first we did take the help of jokes, but the stock of good jokes was over after about 15 days. After that, stale and silly jokes came. Camel jokes, vulgar jokes. It was no good." Members of the laughing clubs say they feel better, some say they have even lost weight, others say they are not depressed, and still others say it has helped to get out of the house, and meet people. Whether or not it is the laughter exercise, the physical exercise, or just being with other people, we all know that when we laugh we simply feel better (Roach 1996).
Laughter should be used as a coping mechanism for stress, though it seems to only be used as an outlet for the emotion produced by humor or happiness. Do we laugh because we are happy, or are we happy because we laugh? Both of these are probably true, but we only exercise the former. Laughter is a fascinating phenomena that works like a medicine. Although most drugs effect everyone differently, laughter is always the same. It exercises your entire body causing you to feel relaxed and pain free. The fact that laughter is good for one's health should be quite evident. So why not laugh? When one laughs, it is like taking a drug, yet there is no such thing as an overdose or, "laughter toxicity," as Kataria says. Maybe we can now say "A laugh a day keeps the doctor away."
Bibliography
• Berk, Lee, Dr.P.H., M.P.H. & Stanley Tan, M.D. Ph.D. (1996). "The Laughter-Immune Connection."
• Cousins, Norman (1979). Anatomy of an Illness As Perceived by the Patient. New York: W.W. Norton & Company, Inc.,
• Finnerty, Amy (1995, September). "Send in the Clowns". American Health, 68-69+.
• Gelkopk, Marc, M.A., Kreitler, Shulamith, Ph.D. & Sigal, Mircea, M.D. (1993) "Laughter in a Psychiatric Ward." The Journal of Nervous and Mental Disease, 283-288.
• Kalat, James W. (1995). "Synapses, Drugs, and Behavior". Pat Gadban & Richard Flyer (Eds.), Biological Psychology (87). California: Brooks/Cole.
• Ljungdahl, Lars (1989). "Laugh If This Is a Joke" Journal of the American Medical Association, 558.
• "Proverbs 17:22."(1989) Bible: King James Version. Republic of Korea: Thomas Nelson, Inc.
• Roach, Mary (1996, September). "Can you laugh your stress away?." Health, 92-96.
• Simonton, O. Carl, M.D., Stephanie Matthews-Simonton, & James L. Creighton. (1978). Getting Well Again. New York: Bantam.
• U.S. Bureau of the Census, Statistical Abstract of the U.S.: 1995 (115th edition.) Washington, DC, 1995.
• Wooten, Patty, RN BSN CCRN. (1995). "Laughter as Therapy for Patient and Caregiver" Jest Home
Article on Laughter 2006 USA
Fairleigh Dickinson University in Teaneck, New Jersey. Prof. Charles Schaefer URL PDF
Even fake laughter is Good Laughter
Psychologists say a minute of forced laughter can help the blues, writes Richard Morin in Washington.
April 1 2003
The news is grim these days, so we all could use a good laugh, even a fake one, says a psychologist who claims that a minute of forced laughter can chase away the blues.
"Forced laughter is a powerful, readily available and cost-free way for many adults to regularly boost their mood and psychological wellbeing," said Charles Schaefer, psychology professor at Fairleigh Dickinson University in Teaneck, New Jersey.
Professor Schaefer also found that self-imposed smiling is a mood enhancer. But howling like a wolf for a minute didn't do anything - except make a racket, Professor Schaefer and his research colleagues reported in two separate studies in Psychological Reports.
His findings come from two experiments he conducted on 39 college students and Teaneck residents. While additional studies with larger samples are needed to bolster his conclusions, Professor Schaefer said, these initial results are important enough to warrant attention.
Professor Schaefer said he uncovered the salubrious effect of artificial laughter in a study of 17 Fairleigh Dickinson students. He first asked them questions that measured their mood. Then he directed them to laugh heartily for a minute, and tested them again. On average, test subjects reported feeling significantly better after 60 seconds of fake merriment.
Why would phony laughter work? Because your body doesn't know it's fake, even though your brain might, Professor Schaefer said. "Once the brain signals the body to laugh, the body doesn't care why. It's going to release endorphins, it's going to relieve stress as a natural physiological response to the physical act of laughing."
Intrigued, Professor Schaefer designed a second study to compare the effects of forced laughter with continuous smiling or howling.
He directed 22 study participants to smile broadly for 60 seconds, laugh heartily for 60 seconds and howl for 60 seconds. Laughing and smiling both helped boost their spirits, but howling didn't, he found. Forced laughter was the best medicine. "One minute of forced laughing showed a significantly greater improvement than one minute of smiling," Professor Schaefer said.
How did test subjects know exactly what to do?
"My research assistant and I would demonstrate," Professor Schaefer said.
"We stood before them and laughed hysterically and then howled. I instructed them to imagine a wolf howling at the moon. When they saw a senior professor howling, it took away some of their natural self-consciousness."
- Washington Post
INTERNATIONAL JOURNAL OF MOLECULAR MEDICINE 8: 645-650, 2001
6 33.3. 45
The elevation of natural killer cell activity induced by laughter
in a crossover designed study
KIYOTAKE TAKAHASHI1, MASAO IWASE1, KO YAMASHITA1, YOSHIHIRO TATSUMOTO2, HIROSHI UE1,
HIROHIKO KURATSUNE3, AKIRA SHIMIZU1 and MASATOSHI TAKEDA1
1Department of Clinical Neuroscience, Psychiatry, Osaka University Graduate School of Medicine,
2Faculty of Social Welfare, Kansai University of Welfare Sciences, 3Department of Hematology and Oncology,
Osaka University Graduate School of Medicine, Osaka, Japan
Received August 17, 2001; Accepted September 14, 2001
_________________________________________
Correspondence to: Dr Kiyotake Takahashi, Department of
Clinical Neuroscience, Psychiatry, Osaka University Graduate
School of Medicine, D3, 2-2 Yamadaoka, Suita City, Osaka 565-
0871, Japan E-mail: kiyotake@psy.med.osaka-u.ac.jp
Key words: laughter, natural killer cell activity, crossover design, electromyogram, pleasantness
limited our study to male subjects due to the unknown effect of female menstrual cycle on NKCA. All the participants were paid ten thousand yens (corresponding to approximately US$80) after the completion of the experimental protocol.
Experimental procedure. The protocol of the experiment is displayed in Fig. 1. Subjects were instructed to avoid intensive exercise, to sleep well, not to take alcohol, tobacco and caffeine
from the day before the experiment and not to have breakfast in the morning of the experimental day. Blood samplings were undertaken at 7:20 a.m. and 9:00 a.m. because of the circadian rhythm of NKCA (7). The experiment started at 7:00 a.m. At first, mood states of the subject were assessed by Profiles of Mood States (POMS), then blood sampling and placement of electrodes and probes to the subject were undertaken. The subject watched a comic film or a nonemotional control film presented in the 14-inch TV monitor approximately 2 m apart, alone in a shielded room. The duration of the films was 75 min. The content of the comic film used in the study was part of comedy series produced by popular Japanese comedians, and that of non-emotional control film was a documentary TV program that did not contain any emotional elements. The subject watched the other film within 4 weeks in the same experimental protocol.
The order of both films was randomized to address potential order effect. During watching a film, electromyogram of left major zygomatic muscle, skin conductance response in the left palm, finger tip plethysmogram of left forefinger, pneumogram, body movement and vocalization were measured using digital electroencephalograph (Synafit 2514, GE Marquette Medical Systems, Tokyo, Japan). According to the guideline of Fridlund and Cacioppo (8), Ag-AgCl surface electrodes with 5 mm diameter were placed on the left major zygomatic muscle, which was mainly involved in the facial
expression of laughter (9). These polygraphical data were recorded in magneto-optical discs. Simultaneously, the facial expression of the subject was recorded with a digital video camera. After watching a film (approximately 9:00 a.m.), the assessment of mood states with POMS, blood sampling, self-rating of the pleasantness of the comic film with visual analogue scale were undertaken. All these measurements were undertaken in the shielded room to minimize environmental noise.
Immunological measurements. We measured NKCA, the percent of NK cell marker (CD16, CD56, CD57), red blood cells, white blood cells and platelets. The measurements were performed at BML, INC (Tokyo, Japan). We assumed CD16+ CD56+ cells as NK cells in the present study (10). To obtain the number of NK cell, the percent of CD16+ CD56+ cell subtype was multiplied by total lymphocytes. NKCA was determined by standard chromium release assay as described by Kay and Horwitz (11) at two effector-to-target ratios (20:1, 10:1). Target cells were 51Cr-labeled human myeloid K562 cells. The assays of NKCA were finished within the day of blood sampling. NKCA elevation was defined as the difference of NKCA before and after the film (NKCA before
film minus NKCA after film). To determine the NKCA per unit cell count, NKCA was divided by the percent of CD16+ CD56+ cell subtype. Quantification of laughter. At first, we removed artifactual activities of major zygomatic muscle from lectromyographic
data by simultaneous and follow-up observation of subjects' faces monitored and recorded with a video camera. In the off-line analysis, mean muscle discharge (V) of zygomatic muscle was calculated from integrated electromyogram, using
data analysing software DaDisp Pro ver 4.0. The details of the analysis were described in our previous study (12).
Psychological measurements. The pleasantness of the comic film was evaluated with visual analogue scale (VAS) of 10 cm bar (full mark is 10 point). We instructed the subjects that the left end of the bar corresponds to no pleasantness and the right
end, the most pleasant state ever experienced. Mood before and after watching comic or control film were evaluated with
646 TAKAHASHI et al: NATURAL KILLER CELL ACTIVITY INDUCED BY LAUGHTER
Figure 1. Protocol of the experiment. From 7:00 a.m. to 7:30 a.m., mood assessment with Profiles of Mood States (POMS), blood sampling and placement of
electrode were undertaken in the given order. At 7:30 a.m., film presentation started and electromyogram of left major zygomatic muscle, skin conductance
response, finger tip plethysmogram, pneumogram, body movement were polygraphically recorded during film watching. Facial expression of the subjects was
also recorded using a video camera. At the end of the film (approximately 8:50 a.m.), displacement of electrodes, mood assessment with POMS, self-rating of pleasantness of the comic film and blood sampling were performed.
Profiles of Mood State (POMS). POMS is a questionnaire for mood assessment consisting of six scales of tension-anxiety
(T-A), depression (D), anger-hostility (A-H), vigor (V), fatigue (F), confusion (C). To evaluate sychological
background of the subjects, the 16 personality factor (16-PF) questionnaire and Daily Life Stress Scale (Holmes & Rahe) were performed.
Results Before and after watching the comic film, significant elevation of NKCA was found at the effector-to-target ratio (20:1), (before 26.5%; after 29.4%, df=20, t=1.85, p<0.05, paired T-test, one-tailed), whereas no significant changes were observed before and after the control film (before
27.1%; after 24.8%, not significant). There was no significant changes in the number of NK cells before and after the comic film (before 236 cells/mm3; after 217 cells/mm3, not significant), though the number of NK cells in the control condition indicated significant decrease (before 249 cells/mm3; after 173 cells/mm3, df=20, t=3.27, p<0.01, paired T-test, one-tailed), (Table I). NKCA per unit cell count
did not show significant changes during either the comic or the control conditions. The averaged EMG discharge during the comic was significantly larger than that during the control film (comic 42.4 V; control 7.5 V, df=18, t=4.43, p<0.001, paired T-test, one-tailed). We performed this comparison
among 19 subjects since EMG data of two subjects during control film were incomplete. The average score of self-rated pleasantness of the comic film was 6.2 points. On the other hand, control film did not elicit any pleasantness since all the subjects reported that they did not feel any pleasantness or
funniness at all.
The scores of mood scales measured with POMS are shown in Table II. Significant decrease of scores by the comic film was found in tension-anxiety (df=20, t=2.42, p<0.01, paired T-test, one-tailed), depression (df=20, t=4.06, p<0.001, paired T-test, one-tailed), anger-hostility (df=20, t=1.92, p<0.05, paired T-test, one-tailed), confusion (df=20, t=2.59, p<0.01, paired T-test, one-tailed). Significant changes of scores by the control film were found in anger-hostility (df=20, t=1.90, p<0.05, paired T-test, one-tailed), vigor (df=20, t=3.75, p<0.001, paired T-test, one-tailed) and fatigue (df=20, t=1.96, p<0.05, paired T-test, one-tailed).
To examine the contribution of experiential and expressive aspects of laughter to NKCA elevation, the correlation of NKCA elevation with the self-rated pleasantness, the scores of mood scales in POMS and the magnitude of laughter was tested in the laughter experiment. NKCA elevation by laughter had significant negative correlation with the scores of depression (r=-0.56, p<0.01) and anger-hostility (r=-0.56,
p<0.01) before comic film and those of tension-anxiety
(r=-0.58, p<0.01), depression (r=-0.60, p<0.01), anger-hostility
(r=-0.52, p<0.05) and fatigue (r=-0.48, p<0.05) after the
comic film (Table III), though there was no significant
correlation of NKCA elevation with self-rated pleasantness
and the magnitude of laughter (Table IV). The scores of
depression and anger-hostility had significant negative
correlation with NKCA before and after the comic film. In
further analysis, the subjects were divided into three groups,
namely a group with high depression and high anger-hostility
which exhibited higher scores of both mood scales than each
mean, a group with low depression and low anger-hostility
which exhibited lower scores of both mood scales than each
mean and a group of the rest. The numbers of the subjects
belonging to each group were ten, eight and three before the
comic, and nine, seven and five after the comic film,
INTERNATIONAL JOURNAL OF MOLECULAR MEDICINE 8: 645-650, 2001 647
Table I. NKCA and the number of NK cells before and after
watching the comic and control film.a
–––––––––––––––––––––––––––––––––––––––––––––––––
NKCA (%) NK cell (cells/mm3)
––––––––––––––– ––––––––––––––––
Laughter Control Laughter Control
–––––––––––––––––––––––––––––––––––––––––––––––––
Before 26.5 27.1 240 249
After 29.4 24.8 219 167
p-value
(paired T-test) p<0.05 NS NS p<0.01
–––––––––––––––––––––––––––––––––––––––––––––––––
aLaughter significantly elevated NKCA at the effector-to-target
ratio (20:1), whereas control did not. Significant decrease in the
number of NK cell was found in control condition. NKCA, natural
killer cell activity.
–––––––––––––––––––––––––––––––––––––––––––––––––
Table II. a, The scores of mood scale of POMS before and
after watching the comic film.a
–––––––––––––––––––––––––––––––––––––––––––––––––
T-A D A-H V F C
–––––––––––––––––––––––––––––––––––––––––––––––––
Before 50.4 51.0 48.4 54.3 49.3 50.7
After 47.0 47.9 46.8 55.4 46.8 48.4
p-value p<0.01 p<0.001 p<0.05 NS NS p<0.01
(one-tailed)
–––––––––––––––––––––––––––––––––––––––––––––––––
aThere were significant changes in the scales of tension-anxiety
(p<0.01), depression (p<0.001), anger-hostility (p<0.05), confusion
(p<0.01). T-A, tension-anxiety; D, depression; A-H, anger-hostility;
V, vigor; F, fatigue; C, confusion.
–––––––––––––––––––––––––––––––––––––––––––––––––
b, The scores of mood scale of POMS before and after
watching the control film.a
–––––––––––––––––––––––––––––––––––––––––––––––––
T-A D A-H V F C
–––––––––––––––––––––––––––––––––––––––––––––––––
Before 50.5 52.3 52.0 55.5 50.4 51.3
After 48.4 51.0 49.2 50.4 53.2 52.0
p-value NS NS p<0.05 p<0.01 p<0.05 NS
(one-tailed)
–––––––––––––––––––––––––––––––––––––––––––––––––
aThere were significant changes in the scales of anger-hostility
(p<0.05), vigor (p<0.01), fatigue (p<0.05).
–––––––––––––––––––––––––––––––––––––––––––––––––
respectively. The comparison of NKCA elevation in the former two groups revealed significantly lower NKCA elevation in the group with high depression and high angerhostility before and after the comic film [before 7.1% (low group) and -2.5% (high group), df=16, t=3.25, p<0.005, Student's t-test, one-tailed; after 6.0% (low group) and -2.3% (high group), df=14, t=2.30, p<0.05, Student's t-test, one-tailed]
(Fig. 2).
To examine the relation of experiential and expressive aspects of laughter with NKCA before and after the comic film, the correlation of NKCA with self-rated pleasantness of the comic film and the magnitude of laughter was statistically tested. Self-rated pleasantness had tendency of correlation with NKCA before and after the comic film (NKCA before comic r=0.395, p<0.1; NKCA after comic r=0.428, p<0.1), though there was no significant correlation of NKCA with the magnitude of laughter (Table IV).
There was no relation between the results of 16-PF questionnaire and NKCA elevation and NKCA before and after the comic film.
Discussion
Although the elevation of NKCA by laughter was suggested by previous studies (5,6), the results were uncertain due to the small sample size in these studies. Another study, which lacked the comparison to control group, failed to indicate NKCA elevation by humorous video (13). The present study
conquered methodological issues of the previous studies using large sample size and a crossover designed experiment and demonstrated significant NKCA elevation by laughter and no NKCA changes by the control film. In regard to the number of NK cells, significant decrease during control was
found. It is known that NKCA has circadian rhythm of the highest activity in the early morning and the lowest activity in
648 TAKAHASHI et al: NATURAL KILLER CELL ACTIVITY INDUCED BY LAUGHTER
Table IV. Correlation of NKCA before and after the comic
film and NKCA elevation with the magnitude of laughter
evaluated with electromyogram and self-rated pleasantness
of the comic film.a
–––––––––––––––––––––––––––––––––––––––––––––––––
NKCA
–––––––––––––––––––––––––––––––––––
Before After Elevation
–––––––––––––––––––––––––––––––––––––––––––––––––
EMG NS NS NS
VAS 0.395b 0.428b NS
–––––––––––––––––––––––––––––––––––––––––––––––––
aSelf-rated pleasantness of the comic film had tendency of
correlation with NKCA before and after the film. EMG, the
maginitude of laughter evaluated with electromyogram; VAS, selfrated
pleasantness of the comic film using visual analogue scale;
before, NKCA before the comic film; after, NKCA after the comic
film; elevation, NKCA elevation. bp<0.1.
–––––––––––––––––––––––––––––––––––––––––––––––––
Table III. Correlation between NKCA elevation and the scores
of mood scales of POMS before and after the comic film.a
–––––––––––––––––––––––––––––––––––––––––––––––––
T-A D A-H V F C
–––––––––––––––––––––––––––––––––––––––––––––––––
Before NS -0.56b -0.56b NS NS NS
After -0.58b -0.6b -0.52c NS -0.48c NS
–––––––––––––––––––––––––––––––––––––––––––––––––
aNKCA elevation was negatively correlated with the scores of
depression and anger-hostility before watching the comic film and
those of tension-anxiety, depression, anger-hostility and fatigue after
the comic film. T-A, tension-anxiety; D, depression; A-H, angerhostility;
V, vigor; F, fatigue; C, confusion. bp<0.01; cp<0.05; onetailed.
–––––––––––––––––––––––––––––––––––––––––––––––––
Figure 2. NKCA elevation of the low depression and low anger-hostility (low D and A-H) group and high depression and high anger-hostility (high D and A-H)
group. The subjects were divided into three groups according to the scores of D and A-H before and after the comic film, namely a group with high D and A-H
which exhibited higher scores of both mood scales than each mean, a group with low D and A-H which exhibited lower scores of both mood scales than each
mean and a group of the rest. High D and A-H group exhibited significantly lower NKCA elevation than low D and A-H group before (left) and after (right)
the comic film.
Before the comic film After the comic film
the evening (7). Thus, decrease in the number of NK cells
during the control film could be explained by circadian
rhythm. On the contrary, no significant change of NK cells
was observed during the comic film. These findings suggest
the increase in the number of NK cells during laughter
compared with the control. NKCA per unit cell count
indicated no significant changes in either experiment. In
summary, NKCA elevation by laughter could be related with
the number of NK cells rather than NKCA per unit cell
count.
As indicated in Table IIa, the comic film significantly
improved the scores of negative mood like tension-anxiety,
depression, anger-hostility and confusion. The average of
self-rated pleasantness of the comic was 6.2 point. These
findings suggested sufficient pleasantness induced by the
comic film. Non-emotional control film significantly
aggravated the scores of vigor and fatigue. It is possible that
the scores of vigor and fatigue in the control experiment
might be affected by experimental environment where
subjects watched a film with electrodes and probes on their
face and body, though control film should have no effect on
mood essentially. In summary, the data of mood scores
assessed by POMS clearly indicated that the comic film
improved the mood of the subjects compared with the control
film and that both films were appropriate as visual stimuli.
The relation between NKCA elevation and experiential and
expressive aspects of laughter is of importance. The present
study indicated that the scores of negative mood in POMS
were negatively correlated with the elevation of NKCA by
laughter. Further comparison between the group with high
depression high anger-hostility and the group with low
depression low anger-hostility group revealed that high scores
of depression and anger-hostility suppressed NKCA elevation
by laughter. The present study also indicated that higher scores
of pleasantness to the comic film tended to be related with
higher NKCA, implying that high sensitivity to pleasant stimuli
predicts high NKCA before and after the comic film. On the
other hand, the magnitude of laughter evaluated with EMG
did not show significant correlation with NKCA elevation or
NKCA before and after the comic film. These findings
suggest that the immunological effect of laughter could be
attributable not to expressive aspects like the magnitude of
facial expression of laughter but to subjective experiential
aspects like mood states and pleasant emotional experience to
the comic film.
It is known that physical exercise elevates NKCA via
marked increase in circulating NK cell number (14). It is
reported that NKCA elevation during exercise is mediated by
epinephrine (15). Laughter is an emotional expression with
facial expression as well as somatic motion like vocalization
and body movement, while epinephrine, norepinephrine and
cortisol were lowered during mirthful laughter (16). The present
study did not indicate marked increase in NK cell number by
laughter. These findings suggest distinct mechanism of NKCA
elevation by laughter from that during physical exercise. Recent
studies in neuroscience indicate that experiential aspects of
emotion are related with medial prefrontal and orbitofrontal
cortices (17) which have dense connection to hypothalamus.
The present study suggests the relation between experiential
aspects of laughter and NKCA and NKCA elevation. It might
be postulated that the activities of brain regions related with
pleasantness should affect hypothalamic activities, which could
regulate systemic immune function via autonomic nervous
system and/or hypothalamus-pituitary-adrenal axis.
Although our results demonstrated NKCA elevation by
laughter in the short-term experimental environment, it is still
unclear whether the immunological effect of laughter persists
for a long period and whether laughter has actual preventive
and curative effects on viral infection, cancer and chronic
fatigue syndrome (CFS) in which NK cell is believed to play
an important role. Reportedly, psychological intervention to
the patients with breast cancer significantly improved the
survival period (18). Another study reported that psychotherapy
to the patients with malignant melanoma significantly elevated
NKCA after 6 months (19). These lines of evidence support
the idea that psychological intervention to cancer by laughter
could be effective. CFS is currently an operational concept to
clarify the unknown etiology of the syndrome characterized
primarily by chronic fatigue. The characteristic symptoms of
CFS are: prolonged generalized fatigue, muscle weakness,
myalgia and postexerertional malaise. It is well known that
most patients with CFS have a deterioration of NKCA (20),
and so CFS has been referred to as low NK syndrome
(LNKS) (21). Since LNKS seems to be related to the
pathophysiology of CFS, much attention has been paid to
how to treat LNKS. Chinese herbal medicine is frequently
used to elevate NKCA in Japan. The improvement of NKCA
was found in some of patients with CFS after this
administration, but it is not enough. If laughter is effective in
elevating NKCA in these patients, it will be a novel
intervention for CFS available in daily life. Our preliminary
examination in the same protocol revealed NKCA elevation
in 4 of the 8 patients with CFS. We expect that laughter is
effective for activating NKCA not only in normal human
volunteers but also in some patients with CFS.
In the future, well-designed prospective studies are needed
to verify the hypothesis that laughter has preferable effects on
various diseases like cancer, viral infection and CFS via NKCA
elevation.
Acknowledgements
The present study was supported in part by a grant and by the Special Coordination Funds for Promoting Science and Technology from the Ministry of Education, Culture, Sports,
Science and Technology, the Japanese Government.
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