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Chapter VIII
IS HUMOR THE BEST MEDICINE?
Paola Gremigni
Department of Psychology, University of Bologna, Italy
ABSTRACT
This chapter presents a brief and rather selective survey of the recent empirical literature dealing with
humor and physical health. After summarizing the potential mechanisms by which humor and laughter
may influence health, the results of fifty relevant articles published between 2001 and 2011 were
analyzed. Overall, findings suggest that mirthful laughter may produce muscular relaxation, beneficial
effects on vascular function, reduction of pain, and have beneficial immunological and endocrine
effects, whereas inconsistencies were found about the beneficial effects of laughter on asthma and
COPD. Results also suggest that people with a greater sense of humor are not objectively healthier than
others and are more likely to engage in unhealthy lifestyles. However, promising findings suggest that a
good sense of humor may lead to a longer life. Some support was found for the idea of humor as a
stress-moderator, although the results of studies on coping humor and stress are contradictory. Finally,
results support the idea that different styles of humor may facilitate or inhibit the potential to deal
effectively with stressors and may promote or impede more general positive life outcomes. Indications
for future research include distinguishing between different types of laughter that may have different
health-promoting effects, and between objective and subjectively perceived health as determined by
various humor styles.
INTRODUCTION
The title of this chapter is taken from a study from the early seventies in which Fry and Williams ques-
tioned the positive effects of laughter on health [1]. Forty years have passed since then, and a number
of studies have been conducted in this field, but this question has not found a strictly evidence-based
answer yet.
When we speak about humor, we refer to a term, with generally positive connotations, indicating the
ability to perceive, enjoy, or express what is amusing, comical, incongruous, or absurd.
Max Eastman says: “We come into the world endowed with an instinctive tendency to laugh and have
this feeling in response to pains presented playfully” [2: 45].
This idea that humor is a natural tendency that mitigates the impact of pain is consistent with the old
adage that “laughter is the best medicine.” In the humor literature, the assumption that a greater sense
of humor promotes physical health has also been very popular [3]. However, only towards the seventies
did doctors and psychologists begin to show a growing interest in the influence of laughter, sense of
humor, and other positive experiences on the human body. Since then several authors have shared the
belief that humor/laughter is the basis of good mental and physical health, a valid antidote or at least a
moderator in the stress-health relationship, and an effective social lubricant. In more recent years a pos-
itive attitude toward humor has characterized part of the research, which has sought to demonstrate the
benefits of humor on physical health. Nevertheless, previous reviews of the empirical literature found
controversial findings and concluded that a weak relationship could be established between humor or
laughter and health [4−6].
This chapter presents a brief and rather selective survey of the recent empirical literature dealing with
humor and physical health. The review is based on a search of Scopus and PubMed to locate articles
published in the last 10 years (i.e. from 2001 to 2011) reporting original empirical research relating to
humor or laughter and various aspects of physical health. For articles published before 2001, I am re-
ferring to the review of the literature published by Rod Martin in 2001 [4]. Fifty relevant publications
were found, the results of which are briefly reported in the following paragraphs.
First, however, I discuss two preliminary issues. The first one is related to the fact that the findings pre-
sented here include research on the effect of both humor and laughing on health. Humor is a multifac-
eted concept, which involves cognitive, emotional, behavioral, psychophysiological, personological,
and social aspects. For example, sense of humor is viewed as a personality trait or an individual-differ-
ences variable, whereas laughter is the most common behavioral expression of the humorous experi-
ence. Although laughter may also be caused by non-humorous stimuli (e.g., tickling or embarrassment)
and can be triggered by imitation (watching other people laugh) [7], humor is also seen as both the
cause for laughter, and the result of laughter and that is why humor and laughter are so closely associ-
ated [8]. It is probably by assuming this close association that few studies analyzed whether the effects
or benefits they have found are due to the experience of humor, the act of laughter or the combined in-
fluence of both. Therefore, research findings are classified here based on outcomes (e.g., physical
health, pain and stress reduction, longevity, etc.), rather than of the relative contribution of humor vs.
laughter.
Second, in the next paragraph, I briefly summarize the potential mechanisms by which humor and
laughter may influence health.
MECHANISMS LINKING HUMOR TO HEALTH
A dominant conceptualization in the study of humor is that it has positive effects on health. However,
the health-humor relationship is more complicated than it seems. First, health is not a unitary concept;
in fact, it consists of different aspects and components, such as physical, mental and social wellbeing,
according to the World Health Organization. Second, even humor is a complex phenomenon that in-
cludes physiological, emotional, cognitive, social, and behavioral components. We can therefore as-
sume that distinct components of humor can influence different aspects of health in a variety of ways..
Several potential mechanisms by which humor and laughter may influence physical health have been
proposed [7]. The first mechanism considers the physiological changes produced by laughter the cru-
cial element in the humor-health relationship. This approach stresses the importance of laughter, which
should not be necessarily accompanied by fun and humor. In this regard, various authors suggest that
laughing out loud trains and relaxes muscles, improves breathing, stimulates circulation, increases the
production of endorphins that reduce pain, decreases the production of stress hormones and strengthens
the immune system [9]. So this first approach suggests that laughter in itself has beneficial effects be-
cause it stimulates the whole body.
A second mechanism suggests that the benefits of humor on health are related to the positive emotional
states accompanying humor and laughter. This approach, unlike the previous one, does not believe that
laughter influences health directly, but rather that it is a means to generate positive emotional states.
Positive emotions, for their part, can influence health, for example, increasing tolerance to pain,
strengthening the immune system, or reducing the cardiovascular consequences of negative emotions
[10].
The third proposed mechanism suggests that humor affects health indirectly by moderating the impact
of stressful events. According to this perspective, a humorous vision and the ability to see the funny
side of problems mitigate the negative consequences of adversity. Referring to the transactional model
of stress proposed by Lazarus and Folkman [11 ], humor can be considered as a form of cognitive as-
sessment that allows an individual to perceive potentially stressful situations in a more positive, less
threatening way. This approach gives more importance to the perceptual-cognitive component of hu-
mor and to the ability to maintain a humorous vision during stressful situations. Humor is therefore
seen as a coping strategy in daily life.
humor can affect health by promoting healthy lifestyles. A great sense of humor is expected to be
linked with engagement in behaviors that promote health such as taking regular physical activity, fol -
low proper nutrition, maintaining appropriate weight, and avoid smoking or consuming too much alco-
hol. This mechanism is grounded on a hypothetical underlying link between sense of humor, self-es-
teem, optimism, and self-protective health behaviors [6].
All the hypothetical mechanisms presented above might suggest that people with a great sense of hu-
mor have a better physical health, as indicated by fewer symptoms (e.g., chronic pain or cardiovascular
problems), improved physiological functioning (e.g., a low-pressure level), and higher satisfaction with
their health. However, looking at the studies published before 2001, it was difficult to find a simple, di-
rect association between sense of humor and a good health status. For example, some studies have
found negative correlations between sense of humor and symptoms of disease [12 ], while others have
found no relationship [13]. Furthermore, most studies were not driven by an explicit intention to verify
one or more of the above-mentioned potential mechanisms linking humor to health. Martin [4] pro-
vided a comprehensive review of the empirical studies investigating associations between
humor/laughter and various aspects of health (i.e., immunity levels, pain tolerance, self-reported illness,
stress-moderating effects, and longevity). This review concluded that there was only very limited evi-
dence for the positive effect of humor and laughter on physical health-related variables. Since Martin
clearly highlighted the methodological weaknesses of research in this field, my goal for this chapter is
to see if the latest research offers more robust and consistent evidence of the link between humor and
health.
LAUGHTER AND PHYSICAL HEALTH
CARDIOVASCULAR ACTIVITY
A very common notion is that the physiological changes associated with laughter, such as increased
cardiovascular activity, have a positive impact on physical health [3]. However, previous studies based
on physiological measures found that laugher manipulation did not result in a lower heart rate or de-
crease blood pressure [14 ].
More recently, a link between laughter and the healthy function of blood vessels was reported by re-
searchers at the University of Maryland Medical Center, indicating that laughter after watching a comic
movie segment caused the dilatation of the inner lining of blood vessels (i.e., the endothelium), and in-
creased blood flow [15].
Vlachopouloset and his colleagues [16] investigated the effect of laughter and mental stress on arterial
stiffness and central hemodynamics, which are independent predictors of cardiovascular risk. The ef-
fects of viewing a 30-minute segment of two films inducing laughter or stress were assessed, using
carotid-femoral pulse wave velocity as an index of arterial stiffness and augmentation index as a mea-
sure of wave reflections. Results indicated that laughter decreased pulse wave velocity, augmentation
index, and cortisol levels, and increased total oxidative status, whereas stress produced opposite effects,
and hence laughter seems to have a protective role against cardiovascular risk.
Another study published in 2010 [17 ] investigated the effects of mirthful laughter on endothelial func-
tion and central artery compliance, using a controlled crossover study and ultrasound imaging to mea-
sure the effect of watching 30 minutes of a comic movie vs. a documentary. The results were that heart
rate and blood pressure, ischemia-induced brachial artery flow-mediated vasodilation, and carotid arte-
rial compliance increased significantly, while watching the comedy, whereas no such changes were
seen while watching the documentary. Comedy-induced changes in arterial compliance were signifi-
cantly associated with baseline flow-mediated dilation. These results suggest that mirthful laughter
elicited by comic movies has a beneficial impact on vascular function.
Miller and Fry [18], overviewing the studies on the effect of laughter on endothelial vasoreactivity, hy-
pothesized that mirthful laughter may induce the release of beta-endorphins, which in turn activates re-
ceptors on the endothelial surface to release nitric oxide (NO). Endothelial derived NO induces smooth
muscle relaxation, vessel dilation, and may reduce vascular inflammation.
Overall, empirical studies suggest that laughter may produce beneficial effects on the vasculature.
Although there is not a lot of research specifically looking at the impact of humor on heart health, the
findings discussed above suggest that humor can play a role in promoting cardiac health in both healthy
individuals and cardiac patients. The first study to deal purposely with this question was conducted in
2000 by Michael Miller, at the University of Maryland Medical School [19 ]. This correlational study
found that patients who had had a heart attack or had undergone a cardiac surgery found less humor in
life and were 40% less likely than the heart-healthy individuals to laugh in a variety of different situa-
tions. These findings suggest that a sense of humor may provide some protection against heart disease,
but the correlational design of the study did not allow analyzing whether patients were less inclined to
respond to situations with humor due to their recent cardiac event. Prospective studies are therefore
needed to determine whether non-symptomatic people with a lower sense of humor are more likely to
develop heart disease at a later time.
MUSCULAR RELAXATION
Reduced muscle tension is one of the physiological changes associated with laughter, which were pro-
posed to have a positive impact on physical health [3],
The effect of laughter on muscle relaxation was recently documented [20], based on Paskind’s earlier
work that indicated a period of muscular relaxation follows laughter. The Overeem and co-workers’
study examined how laughter and several other respiratory movements influenced spinal motor ex-
citability, as measured by the Hoffmann reflex (H-reflex). The H-reflex is a clinical method of mea -
surement, where the stimulus is an electric shock to sensory fibers coming from muscle spindles, and
the response is recorded using an electromyography. When looking at the H-reflex, increased twitching
indicated increased spinal cord excitability. Findings from this study indicated that both laughter and
simulated laughter decreased spinal motor excitability, and that true laughter evoked more H-reflex de-
pression than simulated laughter, which suggests that mirth on its own can depress the H-reflex, lead -
ing to the post-laughter muscle relaxation response noted in Paskind’s earlier work.
From studies of the same authors, we can conclude that laughter produces relaxation automatically and
naturally, periods of intense laughter are followed by relaxed muscle tone, and genuinely mirthful
laughter (i.e. laughter associated with the experience of humor) triggers a stronger muscle relaxation ef-
fect than laughter without mirth [20,21]. Two separate mechanisms may cause the relaxation. Muscles
not directly participating in the act of laughter tend to relax while laughing. When we stop laughing,
muscles that were contracted when involved in laughing relax. As in any other physical activity, these
two mechanisms, in combination, produce a general pattern of muscle relaxation throughout the whole
body. This natural relaxation effect may help reduce stress, alleviate headaches, rheumatism, neuralgia,
or other conditions characterized by a spasm-pain-spasm cycle.
RESPIRATORY FUNCTION
In addition to changes in muscle tone, there is evidence that laughter leads to changes in respiratory
function. Fry’s work demonstrated that laughter leads to episodes of sharply sporadic deep breathing
[3]. Laughing consists of repeating over and over a process where the air is repeatedly pushed out of
the lungs followed by the taking of a deep breath. This process helps to get rid of the excess carbon
dioxin and water vapor that is built up and to replace it with oxygen-rich air. Individuals with a respira-
tory illness are more likely to have a superficial breathing pattern, which leaves a larger than desired
volume of residual air in the lungs. After some time, in this residual air the oxygen content decreases
and water vapor and carbon dioxin increase, creating a favorable environment for pulmonary infection.
Therefore, it seems safe to assume that laughter may contribute to pulmonary health in patients with
respiratory illness. Unfortunately, very little research has been done on the pulmonary benefits of hu-
mor and laughter.
One pulmonary condition for which researchers have recently investigated the benefit from humor is
asthma. Asthma is a chronic condition characterized by muscle spasms, mucous, and inflammation of
the airways that is spreading rapidly. In a 2004 paper, Kimata compared watching a humorous or non-
humorous film on patients with bronchial asthma and their reaction to triggers [22]. Watching the
funny movie reduced the asthmatic reactions, by significantly reducing the level of bronchial constric-
tion among asthmatics, enabling them to breathe more easily. Laughter appears then to be useful in
controlling allergic asthma.
However, it should be noted that Kimata’s work on asthma appears to contradict an earlier Australian
study that indicated that hard laughter was a common trigger for asthma attacks in children [23 ].
Laughter was more commonly reported as a trigger than excitement. Coughing was the most prominent
symptom, and symptoms mostly occurred within 2 minutes of the mirthful stimulus. The same author
reported a year later that 42% of the 105 patients surveyed reported mirth-triggered asthma [24 ].
Bronchial asthma can be triggered by allergic reactions, various pharmacological agents, the environ-
ment, occupation, infections, exercise and emotions. It was suggested that laughter, as a form of exer-
cise and as an emotional response, is a potent stimulus that triggers bronchial asthma. Furthermore, hy-
perventilation might be a cause of laughter-associated-asthma, in addition to stimulation of irritant re-
ceptors in the airway epithelium.
These inconsistencies in asthma research may be reconciled by shifting the focus on the level of emo -
tional arousal experienced. Moderately humorous events accompanied by mild laughter support good
pulmonary function among asthmatics, while extreme funniness accompanied by extended laughter in -
terferes with it.
A very recent area of research is related to the possible value of harm of laughter for a patient with
chronic obstructive pulmonary disease (COPD). COPD condition is characterized by impaired ability
to rid the lungs of air, leading to hyperinflation. In COPD patients, strong laughter could increase the
level of trapped air, because their lungs do not permit the rapid expulsion of air that occurs with a
strong laugh. One recent study [25] showed that laughter can reduce hyperinflation and air-trapping
through repetitive expiratory efforts in patients with severe COPD, although this reduction was no
longer existent two hours later. Nevertheless, it was moderate laughter that was associated with reduced
lung volume, while intense laughter was associated with increased hyperinflation. A more recent study
also found that laughing aloud may cause acute deterioration in pulmonary function secondary to wors-
ened hyperinflation in COPD patients [26].
These studies on COPD lead to the same conclusion reached for asthma: in people with respiratory dis-
eases, extended hearty laughter leads to lung health detriments, whereas mild laughter supports good
pulmonary function.
PHYSICAL SYMPTOMS
Past research attempting to determine if an association exists between an increased sense of humor and
a reduced number of physical symptoms has been generally inconclusive. Several investigators have re-
ported findings supporting the link between greater humor and fewer physical symptoms, including
colds, upper respiratory infections, nausea, diarrhea, pounding heart, dyspnea, musculoskeletal pain,
and blood pressure; whereas several others have found no evidence for such a relationship. In his re-
view, Martin [4] concluded that very little evidence supports a simple relationship between measures
of humor and disease symptoms.
A more recent study [27] explored the extent to which different humor styles and negative affect pre-
dict physical health. Results showed that an increased number of physical symptoms was associated
with higher levels of negative affect, but were unrelated to the humor styles. Neither adaptive humor
was associated with a reduction in physical symptoms nor was maladaptive humor associated with an
increase in symptoms. As such, these findings were consistent with prior work demonstrating that sense
of humor is not linked to physical symptoms.
A study by Svebak, Martin and Holmen [28], conducted in Norway on a sample of more than 65,000
subjects, also offers few confirmations for a direct relationship between humor and physical symptoms.
This large study included health-related measures such as common bodily symptoms (e.g., nausea,
diarrhea, pounding heart, dyspnea, musculoskeletal pain, and blood pressure), subjective health
satisfaction, and measures of sense of humor and laughter expressiveness. There was no significant
relationship between sense of humor and symptoms of illness, or between humor and objective
indicators of health, although the study found a weak correlation between sense of humor and the
satisfaction of participants with their health status.
Overall, these results suggest that people with a great sense of humor are not objectively healthier than
others. Nevertheless, they seem to be subjectively more satisfied with their health. This could be
because people with more sense of humor, having a more positive outlook on life, tend to
underestimate their physical symptoms.
HUMOR AND PAIN REDUCTION
A major impetus for the increased popularity of humor and health was the publication, in 1976, of
Norman Cousins' article “Anatomy of an Illness” in the New England Journal of Medicine, expanded
into a best-selling book in 1979. Cousins claimed that 10 minutes of hearty laughter a day had a
reliable analgesic effect, providing pain-free sleep, and contributed to his recovery from ankylosing
spondylitis, a progressive and painful rheumatoid disease involving inflammation of the spine.
Although it is unknown whether Cousins' recovery can be attributed to the laughter or to other factors
(e.g., the massive use of Vitamin C, particular personality traits such as optimism, a misdiagnosis in the
first place, etc.), these observations have given rise, in particular, to the idea that laughter reduces pain.
In the recent literature, several studies have addressed the study of humor and/or laughter and their
effects on pain perception and tolerance.
Pain threshold and tolerance are usually measured using procedures that were developed in traditional
experimental studies of pain, in which participants are exposed to painful stimuli. The most popular is
the cold pressor test, in which participants are asked to immerse their arm in a tub of ice-cold water for
up to a few minutes. Pain threshold is defined as the amount of time elapsed before the participant re-
ports the stimulus to be painful, while pain tolerance is the duration of time before the individual can-
not tolerate the stimulus any longer and wishes to terminate it.
In past research, although there was considerable experimental evidence of increased tolerance to pain
stimuli after exposure to humor [29 ], contradictory results were also presented [30].
Of particular interest are more recent studies on the impact of humor and laughter on pain perception
and tolerance, as they investigated issues rarely examined before. An experiment by Karen Zweyer and
her colleagues [31] was designed to clarify whether the effects of humor on pain reduction are due to
laughter, in particular, to the positive emotion of mirth, or to other factors such as the cognitions in -
volved in humor. In this study, participants watched a comedy film that contained sound effects but no
dialogue, and they were instructed to enjoy the film but inhibit all smiling and laughter, or smile and
laugh as much as possible during the film, or produce a humorous narrative while watching the film.
Using the cold pressor procedure, pain tolerance was measured before, immediately after and 20 min -
utes after the film. The researchers also videotaped the participants during the procedure, and subse-
quently coded their facial expressions for genuine (Duchenne) and forced (non-Duchenne) smiling and
laughter. The three conditions yielded similar significant increases in pain threshold and tolerance. Re-
sults indicated that the exposure to a humorous stimulus per se had a reduction effect on pain, probably
due to feelings of amusement; while neither laughter nor humor productions were necessary. Moreover,
the observed increases in pain tolerance were found to be positively associated with genuine enjoyment
smiles (Duchenne display), but not with the frequency or intensity of laughter.
A study by Diana Mahony and her colleagues [32 ] investigated the role of expectancies in humor-re-
lated increases in pain tolerance. In this study, before being shown a humorous videotape, the partici-
pants were told that humor is known to increase pain tolerance (positive expectancy condition), or that
humor has been shown to decrease pain tolerance (negative expectancy condition), or they were told
nothing about the effects of humor on pain (no expectancy condition). Following exposure to the com-
edy, the positive expectancy and no expectancy groups both showed significantly greater increases in
pain thresholds than the negative expectancy group. These results suggest that a humor-related in-
creases in pain tolerance are mediated by expectancies.
Some explanations of the effect of humor on pain tolerance suggest that laughter may stimulate the pro-
duction of endogenous opioids such as beta-endorphins, thereby increasing pain tolerance in the face of
physical illness or disease. Recently, Dunbar and colleagues [33] recalled the hypothesis that laughter
plays a crucial role in increasing pain tolerance through an endorphin-mediated opiate effect. Endor-
phins are endogenous opioid peptides produced in the central nervous system that function as neuro-
transmitters, but also play a crucial role in the management of pain through their analgesic properties. A
series of six experimental studies in both the laboratory (watching videos) and naturalistic contexts
(watching stage performances), using change in the pain threshold as an assay for endorphin release,
showed that pain threshold was significantly higher after laughter than in the control condition. This
pain-tolerance effect was due to laughter itself and not simply to a change in positive affect.
The biological hypothesis of an endorphin-mediated opiate effect is not contradicted by the results of
the studies mentioned above. Even in the case of placebo analgesic effects of humor [32], this does not
negate the possibility that they are mediated by physiological processes, including endorphin produc-
tion in the brain.
Despite the consistent results of studies linking pain tolerance to the experience of humor or laughter, a
recent study showed that the effectiveness of humor in enhancing pain tolerance is the same as that of
other distractors such as music, arithmetic and horror [34 ]. The authors concluded that compelling dis-
traction increases pain tolerance in adults, regardless of whether or not the distraction is humorous.
Relatively little research has been done on the relationship between humor or laughter and pain in chil-
dren. Studies focusing on procedural pain, a distressing problem for children, parents and healthcare
providers, generally have not specifically looked at laughter as a mechanism for mitigating pain. A pre-
liminary study was recently conducted, the findings of which may be extended to healthy children go -
ing through painful procedures, such as diagnostic tests or preventative interventions [35]. This study
involved 18 healthy children watching humorous video-tapes before, during and after the cold-pressor
test. Pain appraisal and pain tolerance were examined in relation to humor indicators (number of laughs
during each video and child ratings of how funny the video was). Although humor indicators were not
significantly associated with pain appraisal or tolerance, children showed significantly greater pain tol-
erance while viewing funny videos than when viewing the videos immediately before or after the cold-
water task. The results suggest that humorous distraction is useful to help children tolerate painful pro-
cedures.
Another study [36 ] examined the humor-pain interface in hospitalized pre-adolescent children who
had undergone a medical intervention. It was a non-experimental study using a correlational design.
Use of pain-specific humor-coping was positively associated with an adaptive problem-focused coping
style, and was also more strongly (and inversely) associated to ratings of pain unpleasantness rather
than sensory intensity. The results were opposite to those of Stuber’s study [35] in that humor was here
associated with more subjective aspects of pain (i.e., appraisal or unpleasantness), rather than objective
aspects (i.e., pain tolerance and intensity).
Chronic pain is another area that has received little attention in recent studies on humor. Chronic pain is
regarded as pain that persists past the normal time of healing, which is generally three months for non-
malignant pain [37 ]. It is associated with negative mood states and poor life satisfaction, and is very
common in later life. Among older people chronic pain has important consequences, including loneli-
ness, social isolation, depression, impaired physical functionality, and increased healthcare utilization
and costs [38]. Since the use of medication for pain relief has proven inadequate, especially in older
people, researchers have tried to see if humor could be an alternative. Recently, a study involved a
group of older people with chronic musculoskeletal pain in a randomly controlled study where an 8-
week humor therapy intervention, based on reading funny jokes and stories, was administered to the
experimental group but not to the control group [39 ]. In the post-intervention there was a significant re-
duction in pain intensity and loneliness and an increase in happiness and life satisfaction in the experi-
mental group that was not found in the control group. Unfortunately, the design of the study does not
allow the effects of the humor therapy to be disentangled from those of the therapeutic relation. Never-
theless, it seems to offer some support to the link between humor and chronic pain control.
Rod Martin [6] suggests that the experiments in the field of humor and pain tolerance have generally
been more methodologically rigorous than in other fields such as the immunity research. Most of the
studies have, in fact, control groups and controlling for confounding variables. Nevertheless, the mech-
anisms involved in pain control and threshold are still not completely clear. According to the gate con-
trol theory, distraction is crucial in the relief and control of pain [40 ]. According to the neurotransmit-
ters theory, the release of endorphins in the brain is another mechanism of pain control [41]. Humor is
an effective distractor, but there is also evidence that it triggers activation of the endorphin system. Fur-
thermore, it is not clear which stimulus generates positive effects, and whether the effect is due to
laughter per se or to the amusement-related positive emotion of mirth, or to the effect of a distractive
stimulus.
In summary, in the recent experimental literature, there is some empirical support for Norman Cousins’
observation that laughter reduces pain, although further studies are needed to explain the exact mecha-
nisms through which this reduction occurs.
HUMOR AND STRESS
HUMOR AS A STRESS MODERATOR
In addition to the more direct physiological effects of humor and laughter on health, it has also been
suggested that there may be several indirect links. Humor might benefit health through cognitive mech-
anisms that moderate the adverse effects of stress on health. In this hypothesized stress-moderator
mechanism, particularly relevant are the cognitive-perceptual aspects of humor, which would be more
important than laughter.
Kuiper and Nicholl [42 ] proposed that two mechanisms, cognitive appraisals and distancing, may play
a fundamental role in the perceptions that more humorous individuals have concerning various facets of
their physical health. Those with greater senses of humor may have a generally more positive orienta-
tion toward life that is congruent with a more positive cognitive appraisal regarding the threats they
confront. A second mechanism that may facilitate people with a greater sense of humor to develop
fewer negative perceptions involves the use of greater cognitive distancing from potential stressors as a
means of protecting the self. This change in perspective was suggested to minimize the possible impact
of unfavorable events, allowing those with greater senses of humor to more effectively cope with life’s
adversities and frustrations [43 ].
Previous research found that a greater sense of humor promoted a more positive appraisal of potentially
stressful events [44 ]. In turn, it was suggested that these indirect effects contributed to lower stress lev-
els, having a beneficial impact on physical health. Results of studies suggested that a humorous outlook
on life helps one to see the funny side of problems that in turn enables individuals to cope more effec-
tively with stress by allowing them to gain a different perspective and distance themselves from stress-
ful situations, ultimately enhancing their feelings of mastery and wellbeing in the face of adversity.
However, Martin, in his 2001 review [4], concluded that empirical evidence in support of this capacity
for humor to mediate the effects of stress on health was scarce.
Two more recent studies offered some support to this idea of humor as a stress-moderator. A study con-
firmed that a higher sense of humor may positively influence the perception of stress in a sample of
community adults and undergraduates [45 ]. Abel [46 ] found that, when dealing with the same number
and types of daily hassles, individuals characterized by a high sense of humor reported to have per-
ceived less stress, in the last month, than individuals with a lower sense of humor. More positive ap-
praisals of stressful situations mitigated the level of negative affective arousal and favored the tendency
to use positive coping strategies aimed at redefining a positive direct action on the event and source of
stress. This study seems to confirm what Lefcourt and colleagues [47] suggested, namely that humor
can play its role as a coping strategy. Specifically, as a coping strategy, humor may allow individuals to
find something humorous in the stressful situation, thereby reducing the negative emotional reaction as-
sociated with it, or it may stimulate actions aimed at changing the situation itself.
HUMOR AS A COPING STRATEGY
Research on stress was followed by a major development after the redefinition of the concept of a
stressful event by Lazarus and Folkman [11 ]. According to the transactional model, no event can be
defined as stressful in itself, but only when the person perceives a discrepancy between the demands of
the situation and their ability to cope with it. This emphasizes the role of the subject as an active agent
able to influence the impact of stressful events by adopting specific coping strategies. Coping is defined
as the multiplicity of cognitive, emotional and behavioral efforts that the person does to process spe-
cific requests, over-rated as surplus, and available resources. Humor has been identified as one of the
healthiest coping strategies, which make those who use them psychologically and physically healthier.
Research on coping humor has focused primarily on populations with special needs and clinical popu-
lations, since coping humor was seen as a mechanism for managing the inevitable stresses of aging or
being chronically ill.
A study exploring the relation between stress and coping strategies in middle-aged women found that a
higher coping humor was associated with lower perceived stress and higher self-esteem (Park, 2010).
Another study [48 ] examined the associations among coping humor, other personal/social factors and
the health status of community-dwelling older adults. Results showed that coping humor and self-effi-
cacy contributed to mental health status in older adults. Moreover, correlations among coping humor,
self-efficacy and social support suggested that a sense of humor may play an important role in reinforc -
ing self-efficacious approaches to the management of health issues.
Other recent studies contradicted these findings. Celso and colleagues [49] investigated the relation-
ships between humor coping, health status, and life satisfaction among older residents of assisted-living
facilities. It was hypothesized that there is a direct association of humor coping on life satisfaction and
a role of humor coping as a mediator in the relation between health status and life satisfaction. Both the
direct association of humor coping on life satisfaction and the intervening role between health status
and life satisfaction were not supported. Another study [50 ] assessed the relationship between humor
and physical/mental health variables in a longitudinal study of individuals with systemic sclerosis, a
progressive rheumatic disease that can be fatal in severe cases. Humor coping did not significantly pre -
dict any of the disease-related outcomes (i.e., severity, pain, disability, and distress), either cross-sec-
tionally or longitudinally. These studies contribute to a growing body of evidence that humor coping
may not be directly beneficial to quality of life in those suffering from chronic disease.
To summarize, the basic idea, emerging from recent studies, is that humor as a coping strategy may al-
low, through a humorous outlook, individuals to achieve more positive interpretations of demanding
and difficult situations. This process weakens the negative relationship between stressful life events and
well-being. However, this mechanism does not work in the case of chronic disease.
HUMOR STYLES AND STRESS
The contradictory results of studies on coping humor and stress strengthen the importance of consider-
ing sense of humor as a multidimensional variable, with components that can be either positive or neg-
ative in influencing experiences. Martin [51] proposed the presence of individual differences in four
styles of humor, reflecting an adaptive or a maladaptive use of humor. Specifically, affiliative humor,
characterized by efforts to build relationships through humor, and self-enhancing humor, characterized
by uses of humor to maintain a positive outlook on life, might positively influence how the individual
copes with stress. The other two styles, aggressive humor, involving humor that attacks or demeans
others, and self-defeating humor, characterized by humor that demeans the self in efforts to build rela -
tionships, might, by contrast, exacerbate stress rather than reduce it.
A recent study [52 ] found that self-enhancing humor was negatively related and self-defeating humor
was positively related to both evaluations of past stressors and anticipated future stressors. This study
also provided initial evidence to support a mediator model in which the role of humor styles in explain-
ing perceptions of stress was mediated through a composite of positive personality styles (i.e., opti-
mism, hope, and happiness). This new mediator model is based on recent research showing that these
positive personality qualities have been more reliable predictors of health and effective coping than
sense of humor. Specifically, research supports the health benefits of greater optimism [53], higher lev-
els of hope as a stable trait [54 ], and stable happiness [55,56]. To better capture this assumed media-
tion role of positive personality traits on the relation between humor styles and perceived stress, in a
subsequent study, Arnie Cann and his colleagues [57] used a longitudinal model, measuring humor
styles and personality at baseline, and perceived stress 8 weeks later in a sample of university students.
Results indicated that the positive personality qualities fully mediated the relationship between self-en -
hancing humor and perceived stress. These personality traits also partially mediated the relationship be-
tween self-defeating and perceived stress. Thus, a self-enhancing humor style appeared to buffer the ef-
fects of stressors, while other styles, such as self-defeating humor, had negative effects, through the
mediation of positive personality qualities. These results also support the idea that the person’s style of
using humor facilitates (or inhibits) the potential to deal effectively with stressors through promoting
(or restraining) a more general positive personality style. Consequently, people who evidence stable
higher levels of optimism, hope, and happiness, supported by a good sense of humor, tend to perceive
their lives as less stressful, and hence report more positive levels of both physical and psychological
health. Cann’s recent study [57] also showed that humor styles that are self-directed are much more
important in understanding how people respond to potential stressors than are those humor styles that
focus on others. In fact, self-enhancing humor style appears to buffer the effects of stressors, self-di-
rected humor that demeans the self is positively related to the levels of stress experienced, and there-
fore, negatively related to self-reported health, whereas the other-directed humor styles are of little im-
portance in understanding the relationship between sense of humor and health outcomes, as confirmed
by previous studies [52 ].
Taken together, findings to date suggest that a more complex approach to the relation between humor
and stress is needed to more clearly identify the role that sense of humor might play in relation to stress
and coping [57].
HUMOR AND THE IMMUNE SYSTEM
Almost thirty years ago, Dillon and colleagues [58] hypothesized that humor, as a positive emotional
state, may be a potential immune system enhancer. This idea was based on research findings indicating
that stressful events and their associated negative affect result in immunosuppression. According to
psychoneuroimmunology theory, it has been therefore postulated that laughter or sense of humor may
affect health through moderation of stress chemicals and/ or immune-enhancement.
The greatest amount of research in this field has focused on immunoglobulin A. Secretory IgA, a part
of the immune system, is a type of antibody found in mucosal areas, including saliva, which represents
the first defense against antigens in these areas. Research carried out on relatively small samples
showed significant positive correlations between scores on humor and the values measured by saliva
(spit) IgA immunoglobulin [58]. However, other studies with larger samples failed to find any correla-
tion between these variables [59]. Rod Martin [4] was especially critical of methodological weak-
nesses in the research on humor and the immune system.
More recent experiments have reported humor-related changes in various components of immunity
measured in blood samples. In one of the most comprehensive reports, Berk [60] reported the results
of a series of five separate studies involving a total of 52 healthy males, who viewed a comedy video
for one hour. Blood samples taken before, during, and after the intervention showed increased im -
munoglobulins A, G and M with several immunoglobulin effects lasting at least 12 hours. IgM and IgG
are other immunoglobulins that, in addiction to IgA, form part of the immune response. These findings
seem to support the modulation of neuroimmunologic parameters by laughter.
Along with IgA, several other cells offer a different kind of immune protection; the most studied
among these are natural killer (NK) cells. NK cells have the role of seeking out and destroying tumor
cells, viruses, and other foreign organisms in the body. Berk [60 ], in the cited series of five studies, re-
ported that exposure to a humorous stimulus also significantly increased NK activity.
Results of another study [61] involving 33 adult women indicated that the effect of humor was medi-
ated by humor response, as the amount of mirthful laughter correlated with the decreased stress in sub-
jects who viewed a humor video. Humor response also played a role in change in NK cell activity fol-
lowing the video. This finding indicated that although sense of humor was not directly related to a
change in NK activity, a significant relationship exists between the amount of laughter and reduced
stress and improved NK activity.
Laughter’s effect on NK cells was also seen in studies with diabetic patients. Hayashi and colleagues
[62] reported changes in gene expression in patients with type 2 diabetes who had been induced to
laugh. They analyzed the changes in 18,716 genes, finding that 23 were significantly changed after lis-
tening to a comic story compared with a boring lecture. Of the genes changed, 4 were involved in an
immune response and 5 were related to the cell cycle, apoptosis, and cell adhesion. In a second study
[63] on diabetic patients, 41,000 genes were analyzed and the laughter experience up-regulated 39
genes, 14 of which were related to NK cell activity. Laughter improved postprandial blood-glucose lev-
els by modulating NK cell activity. A more recent study [64 ] showed that laughter again lowered 2-
hour postprandial blood sugar levels in type 2 diabetics by decreasing the levels of prorenin in blood
(prorenin is involved in the onset of diabetic complications). Laughter also normalized the expression
of the prorenin receptor gene on peripheral blood leukocytes, which is reduced in diabetic patients. An-
other study also found a decrease in plasma prorenin concentrations, together with an increase in
plasma angiotensinogen, in type 2 diabetics over a 6-month period in which they engaged in laughter
therapy [65 ]. Overall, these findings suggest that laughter may inhibit the onset or advancement of dia-
betic complications starting at the level of gene-expression. They again showed that laughter affected
specific genes that mediate NK cell activity and this produced improvement in glucose levels.
A particular interest in the potential health benefits of humor appears to be present among researchers
in Japan. In a Japanese study, healthy participants showed increased levels of certain molecules in their
saliva that are involved in the elimination of free radicals from the mouth, after watching a comedy
videotape [66 ]. Free radicals are molecules implicated in inflammation, aging, and the development of
some types of cancer. Another study investigated the effect of laughter on salivary endocrinological
stress marker chromogranin A (CgA) in a small sample of 11 healthy men [67]. Saliva samples taken
after watching a comic film showed increased levels of CgA, while the control samples showed no sig-
nificant change in CgA levels. This preliminary study also showed a stress relief effect of laughter after
watching the comic film.
Hajime Kimata recently reported research on the role of humor and laughter in reducing allergic reac-
tions in individuals with allergies. Individuals with dermatitis showed a less severe allergic reaction to
skin prick tests after watching a humorous movie than after watching a documentary [68 ]. Viewing a
humorous film was found to decrease IgE production by seminal B cells cultured with sperms from 24
male patients with atopic eczema, suggesting that it may be helpful for the treatment of allergy in the
reproductive tract [69]. Viewing a humorous film was found to elevate markedly salivary testosterone
levels and reduce trans-epidermal water loss values in elderly patients with atopic dermatitis, while
viewing a control non-humorous film failed to do so [70 ]. Decreased salivary testosterone levels and
increased trans-epidermal water loss characterized elderly patients with atopic dermatitis compared
with elderly healthy people. Laughter increased the levels of breast-milk melatonin in both mothers
with atopic eczema and healthy mothers, and feeding infants with increased levels of melatonin-con-
taining milk reduced allergic responses to latex and house dust mite in infants with atopic eczema [71 ].
Patients with an allergy-related bronchial asthma showed reduced asthmatic reactions to allergens after
watching a comedy videotape, whereas no such effect was found with a non-humorous film [22 ]. Fi-
nally, a reduction in allergy-related immunoglobulins in the tears of patients with allergic conjunctivitis
was found after watching a comedy film, but not a non-humorous control film [72]. Taken together,
these experiments suggest that humor may suppress the excessive immune responses that occur in cer-
tain allergic reactions by reducing the secretion of immunoglobulins such as IgE and IgG.
Several studies have investigated the effects of mirthful laughter on the neuroendocrine-immune sys-
tem in patients with rheumatoid arthritis (RA). The most recent is again a Japanese study focusing on
the growth hormone (GH). GA plays an ancillary role in the regulation of immune function and is in -
creased in patients with RA, compared with healthy people [73]. After experiencing mirthful laughter,
induced by a comical story, the level of serum GH in the rheumatoid arthritis group significantly de-
creased, approaching that in the control group.
These Japanese investigations suggest beneficial immunological and endocrine effects of laughter. The
criticism directed at previous studies, including the use of small numbers of participants or inadequate
controls [4], is less applicable to more recent studies, since they have used more rigorous methodolo-
gies. However the evidence is not yet conclusive and further research is needed to explore the mecha-
nisms of these effects in greater detail, using larger samples.
HUMOR AND LIFESTYLES
Lifestyle is the summary of the ways people relate to themselves, with others, with their problems, be-
sides the type of diet, luxury habits (smoking, alcohol, coffee, and drugs), physical activity, and leisure
management. Lifestyle models provide an explanation for poor health where the factors considered as
determinants of disease are perceived as modifiable [74 ].
A lifestyle that is not healthy (e.g., sedentary lifestyle, smoking, unhealthy diet and excess weight, ex-
cessive stress, etc.) accelerates the aging process and then exposes individuals to a significantly ele-
vated risk of developing disabling medical conditions by reducing life expectancy and quality of life.
Low-risk lifestyle factors, on the contrary, exert a powerful and beneficial effect on mortality [75 ]. The
relationship between humor and life styles was investigated in the more general effects of humor on
health. Previous studies do not support the hypothesis that a greater sense of humor is associated with
healthier lifestyles, rather they seem to highlight the opposite effect [4]. At present, two main studies
reach the same conclusion.
A research conducted by Kerkkanen, Kuiper and Martin [76] aimed to capture the effects of humor on
health during three years involving 34 leaders of the Finnish police. The measures of health indices
were: blood pressure, cholesterol level, alcohol consumption, body mass index, and smoking. Results
did not support the hypothesis that humor positively influences health. In fact, further analysis found
some opposed associations, such as that high scores in some aspects of humor were associated with in-
creased obesity, smoking and cardiovascular risk. These results suggest that people with a greater sense
of humor tend to adopt a less healthy lifestyle.
The Terman life-cycle study, which followed a large sample of intellectually gifted individuals over
many decades [77 ], found that those who had a greater sense of humor and optimism as children were
more likely to smoke and drink as adults. This study used a composite cheerfulness measure that in-
cluded sense of humor as a component. Findings indicated that more cheerful people grow up to be
more careless about their health, drink more alcohol, smoke more cigarettes, and engage in riskier ac -
tivities and hobbies than less cheerful people. These detrimental effects were equally evident when
only the sense of humor component was used to predict outcomes. Overall, these longitudinal findings
suggest that a greater sense of humor may actually contribute to a riskier lifestyle and to poorer health
habits, resulting in premature mortality rates.
This association between humor and unhealthy lifestyles could be partly because people with a greater
sense of humor have extrovert personality traits [78 ]. Previous research has shown that extroverts are
more likely than introverts to consume alcohol, to smoke, and to be obese [79,80 ].
Although research supports an association between humor and unhealthy lifestyles, the mechanisms
that underlie this association should be studied in more detail. Findings suggest that humor may have
different health consequences, some of them positive, while others are potentially harmful. Future re-
search should consider how humor styles might play a role in the more global processes connecting sta-
ble differences in the view of the self and the world to health outcomes.
HUMOR AND LONGEVITY
Up to this point, we have seen that humor and laughter, albeit with some uncertainty, make contribu-
tions to good health by strengthening the immune system, as well as reducing cardiovascular reactivity,
damaging effects of stress, and pain. If humor has some beneficial effects on physical health, then we
can reasonably assume that people who more frequently engage in humor and laughter tend to live
longer than their less humorous counterparts. Nevertheless, Martin [4], reviewing the literature, con-
cluded that the research evidence in this regard is not very encouraging. A paradigmatic example is
Rotton’s study [81 ] on longevity and humor, reporting that famous comedians, comedy writers, and
humorous authors did not live longer than serious authors and entertainers. Consistent with these re-
sults are those from a long-term longitudinal study (the Terman Life Cycle Study, begun in 1921). Indi-
viduals found to be more cheerful at age 12 had higher death rates than their less cheerful peers [82 ].
Cheerfulness is a personality trait that tends to be associated with a greater sense of humor. An expla-
nation offered for this finding was that a more cheerful person engages more often in behaviors known
to have health risks.
More recently, studies from Norway documented evidence showing that humor predicts survival rates
among both healthy and seriously ill individuals. One study [83] explored the role of sense of humor
in survival status, measured two years later, in patients diagnosed with end-stage renal failure, a life-
threatening condition that requires regular dialysis. A highly significant increase in survival was
essentially accounted for by sense of humor. Those who scored above the median in sense of humor
increased their odds for survival by on average 31%. The HUNT-2 study [84 ] tracked the health status
of an adult county population over a seven-year period. Among people who developed cancer during
this period, individuals with a high sense of humor had a 70% higher survival rate than those with a
low sense of humor. A more recent paper of the HUNT-2 study [85 ] showed that while hazard ratios
increased with classical risk factors such as cardiovascular disease, diabetes, and cancer, they decreased
with sense of humor. Sense of humor appeared to increase the probability of survival in both
individuals with poor and good subjective health. However, above the age of 65 this effect became less
evident.
Even though the causal mechanism behind the better survival rates of individuals with high sense of
humor is not clear in these Norwegian studies, humor seems to protect against detrimental effects of
stressors and disease-related stressors upon survival. Svebak hypothesized that the link between humor
and survival is mediated by better coping skills shared by those with a higher sense of humor.
An indirect confirmation of the positive effect of humor on longevity comes from a recent original
study [86 ] that observed photographs of 196 professional baseball players taken in 1952 and rated
them for smiling. Smile intensity in photographs predicts mortality occurring by 2009, accounting for
35% of the explained variability in survival, after controlling for other variables (i.e., college
attendance, marital status, birth year, career length, age at debut year, and BMI).
Chida and Steptoe [87 ] conducted a meta-analysis of the prospective studies examining the association
between positive well-being and mortality in both healthy and diseased populations. Positive
characteristics that were associated with reduced risk of mortality in healthy populations and predicted
longevity included sense of humor, besides other variables such as life satisfaction, hopefulness,
optimism and positive personality qualities.
To conclude, while in studies prior to 2000 there was no evidence of a positive effect of humor on
longevity, recent studies are promising in their suggestion that humor may lead to a longer life.
Nevertheless, the mechanisms that underlie this relationship are still unknown, thus requiring further
investigation.
CONCLUSION
Results of the recent (2001-2011) studies discussed in this chapter show a promising positive trend re-
garding the relationship between humor/laughter and physical health outcomes.
Overall, empirical studies suggest that mirthful laughter may induce muscular relaxation, have
beneficial effects on vascular function, reduce pain, and provide favorable immunological and
endocrine effects, whereas inconsistencies were found in asthma and COPD research about the effects
of laughter.
With regards the study of sense of humor and health, results suggest that people with a greater sense of
humor are not objectively healthier than others and are more likely to engage in unhealthy lifestyles.
However, recent studies are promising in their suggestion that humor may lead to a longer life. Some
support was also found for the idea of humor as a stress-moderator, although results of studies on
coping humor and stress are contradictory. Finally, results of recent studies support the idea that
different styles of humor may facilitate or inhibit the potential to deal effectively with stressors and
may promote or impede more general positive life outcomes.
Mahoney and colleagues [88] have proposed that distinct types of laughter, ranging from chuckles and
giggles to belly laughs, may have quite different health-promoting effects. They also pointed out that
only laughter that is associated with positive emotions and the absence of malice may be critical for
physical health benefits. Given the purported theoretical mechanisms linking laughter and health [3], it
may prove worthwhile for future research to continue to explore the potential relationships between
laughter and health with more refined constructs of laughter.
In considering the potential effects of sense of humor on health, Kuiper and Nicholl [42 ] have intro-
duced an important distinction between physical health objectively measured and subjectively per-
ceived, and speculated that a greater sense of humor contributes to a more positive perception of health
than shown by objective indices. Using a sample of undergraduate students, they found that individuals
with higher scores on sense of humor measures reported more positive health-related perceptions, such
as less fear of serious disease or death, less negative bodily preoccupation, and fewer concerns about
pain, although they did not have healthy lifestyles. These results confirmed the hypothesis and were
consistent with findings from the studies of Svebak, Martin and Holmen [28], showing that a higher
sense of humor was related to greater subjective satisfaction with health but not with more objective in-
dicators of health status. People with a greater sense of humor seem to perceive themselves to be
healthier, showing fewer concerns and preoccupation with symptoms of illness, even though they are
not objectively healthier. It may be therefore useful for future research to continue to explore the poten-
tial relationships between humor and health, considering the distinction between objectively and sub-
jectively perceived physical health.
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