The Laughter Prescription: A Tool for Lifestyle Medicine

Abstract

Laughter is a normal and natural physiologic response to certain stimuli with widely acknowledged psychological benefits. However, current research is beginning to show that laughter may also have serious positive physiological effects for those who engage in it on a regular basis. Providers who prescribe laughter to their patients in a structured way may be able to use these natural, free, and easily distributable positive benefits. This article reviews the current medical understanding of laughter’s physiologic effects and makes a recommendation for how physicians might best harness this natural modality for their patients.

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vol. XX • no X American Journal of Lifestyle Medicine
Dexter Louie, BA, Karolina Brook, MD, and Elizabeth Frates, MD
Abstract: Laughter is a normal and
natural physiologic response to certain
stimuli with widely acknowledged
psychological benefits. However,
current research is beginning to show
that laughter may also have serious
positive physiological effects for those
who engage in it on a regular basis.
Providers who prescribe laughter to
their patients in a structured way may
be able to use these natural, free, and
easily distributable positive benefits.
This article reviews the current
medical understanding of laughter’s
physiologic effects and makes a
recommendation for how physicians
might best harness this natural
modality for their patients.
Keywords: laughter; prescription;
lifestyle medicine; treatment
L
aughter is a complex emotional
response to one’s environment,
situation, and stimuli. Studied for
many years, it was not generally
perceived to have any particular healing
effect until 1979, when Norman Cousins
published As Anatomy of an Illness. In
this book, Cousins described laughter as
creating an analgesic effect for pain
caused by his ankylosing spondylitis.
1
Since that time, interest in laughter as a
potential therapeutic option has grown,
both in popular culture as well as in
scientific research, where the field of
psychoneuroimmunology attempts to
explore the impact of laughter on our
physiology and psychology.
Current research indicates that laughter
has quantifiable positive physiologic
benefits. So far, these benefits have been
small and not yet widely corroborated, but
in this era of preventative medicine, they
indicate that research on laughter is not
only timely and useful but also potentially
fiscally sound. This is because laughter is
(usually) free, and often without side
effects. A 2010 review cataloged the
available scientific evidence on the
physical benefits of both spontaneous and
simulated laughter.
2
This article will
update and expand on the 2010 review in
order to enhance practitioners’ general
knowledge and understanding of how
laughter pertains to medicine. Additionally,
we will make recommendations as to how
laughter might be incorporated into a
lifestyle medicine approach.
What Is Laughter?
“Laughter” and “humor,” though often
used interchangeably, have different
definitions. Humor refers to the stimulus,
such as a joke, which evokes a response.
In contrast, laughter refers to a physical
reaction characterized by a distinct
repetitive vocal sound, certain facial
expressions, and contraction of various
muscle groups. One study identified 5
separate types of laughter: genuine
(“spontaneous”), self-induced
(“simulated”), stimulated (eg, tickling),
induced (ie, via drugs), and pathological.
2
Pathological laughter and crying is
typically defined as a disorder of
emotional expression due to damage of
pathways in the cortex and brainstem,
3
and this is distinctly different from the
laughter and humor discussed in this
article. Laughter can be experienced both
individually, for example, while recalling
a particular event, watching television, or
reading a book, or socially in groups, for
example, participating in a yoga laughter
group or sharing stories with friends.
Theories of Laughter:
Why Do We Do It?
Theories of laughter attempt to explain
the psychological motivations behind
550279AJL
XXX10.1177/1559827614550279American Journal of Lifestyle MedicineAmerican Journal of Lifestyle Medicine
research-articleXXXX
The Laughter Prescription:
A Tool for Lifestyle Medicine
Current research indicates that
laughter has quantifiable positive
physiologic benefits.
DOI: 10.1177/1559827614550279.
Manuscript received December 9, 2013; revised May 9, 2014; accepted May 30, 2014. From the University of California, San Francisco,
California (DL); and Harvard Medical School, Boston, Massachusetts (KB, EF). Address correspondence to Elizabeth Frates, MD, Institute of Lifestyle Medicine, Joslin Diabetes
Center, One Joslin Place, Boston, MA 02215; e-mail: efrates1@partners.org.
For reprints and permissions queries, please visit SAGE’s Web site at http://www.sagepub.com/journalsPermissions.nav.
Copyright © 2014 The Author(s)
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genuine, or “spontaneous,” laughter.
Although one review
4
catalogued over
100 individual theories of laughter, the
field is dominated by 3 in particular:
release theory, superiority theory, and
incongruity theory.
5
Release theory
argues that laughter is the physical
manifestation of repressed desires and
motivations. Superiority theory posits
that laughter is a means of increasing
one’s self-esteem at the expense of
others.
6
By contrast, incongruity theory
states that humor is created by a sense of
incongruity between 2 or more objects
within a joke.
7
Currently, there is no
concrete consensus on which theory is
the most valid or most complete.
What Do We Understand
About the Health
Benefits of Laughter
From a Scientific and
Physiologic Perspective?
It is commonly accepted that laughter
produces psychological benefits, such as
improving affect, depression, anxiety,
and stress.
8-10
Nevertheless, there is
growing evidence that laughter as a
physical activity can additionally produce
small but quantifiable positive
physiological benefits. The literature on
laughter can be separated based on the
type of laughter studied: spontaneous or
self-induced.
Spontaneous laughter differs
significantly from self-induced laughter.
The former refers to “genuine” or
unforced laughter, often in response to a
stimulus, whereas the latter describes
laughter that is simulated de novo.
Spontaneous laughter is often associated
with positive mood, whereas simulated
laughter is primarily physical and is not
necessarily associated with positive
emotions or feelings. Neuroimaging
suggests that different neural pathways
are used in these 2 forms of laughter.
11
Do spontaneous and simulated laughter
have the same effect on the body? One
theory, the motion creates emotion
theory (MCET),
2
posits that the body
does not actually know the difference
between intentionally laughing and
laughing instinctively. Therefore, if one
induces oneself to laugh (by simulating
or self-inducing laughter), the body can
be coaxed into an identical physiologic
response. According to the MCET,
simulated laughter can capture the
positive benefits of spontaneous
laughter—but without using any humor
at all. This is distinctly unlike the other
theories of laughter, which argue that the
benefits arise from nonphysical sources,
for example, positive mood.
Positive mood is closely tied to
spontaneous laughter, and it is thought to
have independent cognitive effects of its
own.
12
However, parsing out the
interaction between positive mood and
spontaneous laughter has been difficult. A
study involving 87 subjects reported that
manipulating mood with music and
video—specifically a peppy Mozart piece
paired with a video of a laughing baby,
versus music from Schindler’s List and a
news report about an earthquake—
significantly affected performance on a
creative thinking task of learning
involving the classification of picture sets
with visually complex patterns.
13
However, another study of 60 subjects
randomly assigned to watch a neutral,
positive affect, or comedy video found
that compared to a comedy video
(presumably elicits both laughter and
positive affect), a video that produced
only positive affect and no laughter was
not enough to cause endorphin release.
14
Another study of 33 people found that
natural killer cell activity increased only
when the subject exhibited mirthful
laughter while watching a humorous
video (mean increase of 15.77 LU, P =
.037).
15
Otherwise, if the subject watched
the video but did not laugh, natural killer
cell activity actually decreased. Because of
the difficulty of the task and the paucity
of research on the topic, this article will
consider positive mood and spontaneous
laughter together as a unit, and make no
effort to distinguish between the two.
Spontaneous Laughter
Spontaneous laughter—also known as
“genuine” laughter—has been far more
widely studied. One early study examined
the stress hormones levels of 10 subjects
watching an hour-long humor video.
16
Among experimental subjects, cortisol
decreased from 240 ± 60 at baseline to 90
± 10 a half-hour after finishing the video,
compared to control subjects who
decreased from 390 ± 90 to 270 ± 60 after
the same amount of time. The
experimental group had a significantly
larger reduction (P = .011), although both
groups had a consistent drop from
baseline. A larger, more recent study
involving 52 patients shown a 1-hour
humor video found increases in natural
killer cell activity, IgG, IgM, and other
leukocytes.
17
Other studies (n = 33 and 21)
have corroborated some of these findings,
determining that natural killer cell activity
was higher in the group watching the
comedic video compared to the
control.
15,18
Interestingly, another study of
20 subjects found that an amusing film
actually produced similar increases in
epinephrine and norepinephrine levels as
an aggression-provoking one.
19
The
authors postulated that this was due to the
emotional arousal, which can elevate
sympathetico-adrenomedullary activity
regardless of whether or not the arousal is
positive or negative.
Other studies have linked laughter and
humor with increased levels of pain
tolerance. In one, 200 subjects were
subjected to a painful cold-pressor
stimulus after being shown a film. Those
who viewed a humorous film had a
significant advantage in pain tolerance
time after a 30-minute wait period.
20
Another experiment of 40 subjects found
that a laughter-inducing narrative, as
opposed to other forms of distraction
such as an interesting narrative audio
tape, increased discomfort thresholds.
21
Similarly, a study of threat-induced
anxiety involving 53 subjects found that
those exposed to a humorous tape
recording consistently rated themselves
as less anxious and reported smaller
increases in stress as the time to receive
an electric shock approached.
22
The cardiovascular effects of laughter
appear to be quantifiable, although
potentially short-lived. A study of 10
healthy subjects showed that cardiac
parasympathetic activity decreased
immediately on watching a comedy
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video, and just as quickly returned to
baseline when finished.
23
This was in
comparison to tragedy videos, in which
the parasympathetic activity also
dropped, but did not return to baseline
afterward. Some of the temporary effects
of laughter on the cardiovascular system
are predictable, given that laughter
involves an increase in physical activity
from baseline. A study of 8 subjects
found that laughter appears to
significantly increase stroke volume and
cardiac output, while significantly
decreasing oxygen consumption,
arteriovenous oxygen difference, and
total peripheral resistance.
24
A study of
blood pressure involving 16
normotensive subjects found that
laughing during a blood pressure
measurement increased systolic blood
pressure by an average of 12 points.
25
This research suggests that the body
responds physiologically to a bout of
laughter as it does to a bout of exercise.
In 2011, additional studies further
suggested the positive effects of
spontaneous laughter. For example, a
study presented at the European Society
of Cardiology 2011 Congress found
vasodilative effects lasting up to an hour
after watching a comedic movie scene,
whereas an action scene prompted
vasoconstriction.
26
Another study used
humor therapy as “medication” to treat
agitation in patients with dementia. The
SMILE study found a 20% reduction in
agitation using humor therapy, which is
an improvement comparable to the
common use of antipsychotic drugs but
without the side effects. Agitation levels
remained lower at the 26-week follow up.
In this study, humor therapy used trained
staff as “Laughter Bosses” to act much like
the “Clown Doctors” used in hospitals on
children’s wards to help improve mood
and increase lightheartedness. (SMILE
study results were presented at the
National Dementia Research Forum 2011
on September 22 and 23.)
Self-Induced, or
Simulated Laughter
In contrast to spontaneous laughter, the
proposed benefits of simulated laughter
are largely based on the MCET: that the
physical act of laughing is enough to
create a positive physiologic response.
Research on simulated/self-induced
laughter, as opposed to spontaneous
laughter, is very recent, and therefore
only preliminary results are available.
A randomized control longitudinal
study in India recruited 115 IT
professionals to participate in 7 sessions
of laughter yoga as a way to reduce
stress.
27
The type of laughter yoga used
consisted of bursts of simulated laughter
followed by yogic deep breathing
relaxation techniques. This study found
no significant change in heart rate,
respiratory rate, heart rate variability,
breath rate, or secretory IgA in either
group. However, the laughter yoga group
had a significantly greater drop in blood
pressure (Laughter Yoga group = 7.46
mm Hg; Control group = 3.03 mm Hg),
as well as a lower postintervention
systolic blood pressure (Laughter Yoga
group = 120.78 mm Hg; Control group =
125.96 mm Hg, P < .04). Additionally, the
Laughter Yoga group showed a
significant drop in cortisol levels
(pre-intervention: 0.25 ± 0.14; post-
intervention: 0.18 ± 0.11) whereas the
Control group did not.
Another study of laughter yoga
examined 60 depressed geriatric patients
in Tehran, Iran.
28
Study subjects were
randomized to receive laughter yoga
therapy, exercise therapy, or nothing.
Both laughter yoga and exercise therapy
groups had a significant decrease in
depression scores compared to the
control group (P < .001 and P < .01,
respectively), and the laughter yoga
group had an additional increase in life
satisfaction compared to the control
group (P < .001). Interestingly, no
significant differences were found
between the laughter yoga and exercise
groups.
Summary of Literature
Current literature on laughter is
promising, suggesting that laughter has
many positive physiologic effects on the
body. It remains important, however, to
retain a certain amount of healthy
skepticism until results have been
repeated and reaffirmed. In this vein,
there remains much to do in terms of
determining the duration and long-term
impact of these effects. In terms of
methodology, randomized control trials
are in short supply compared to
intervention trials,
2
as are standardized
instruments to help better compare
results among studies. Increased
methodological rigor will be important
for the future. Furthermore, the
distinction between spontaneous versus
self-induced/simulated laughter remains
an important area for exploring the
MCET. Finally, having higher-powered
studies that can parse out the difference
between positive mood and the physical
act of spontaneous laughter, for instance,
can help further our understanding on
the topic. There is great potential for
future research in laughter. Randomized
controlled large-scale trials are needed to
further elucidate the physiologic effects
of laughter.
Laughter and
Professionalism: Should
Physicians Use Humor
as a Tool to Induce
Therapeutic Laughter?
An important remaining question is
whether or not laughter can be made
into a convenient, useful therapy for
patients. Laughter has no side effects, is
readily accessible—already permeating
many of our daily social interactions.
Thus, whether the intent is to help a
patient achieve positive physiologic
benefits or simply enhance provider–
patient communication, it deserves a
closer examination to determine its
applicability in the medical setting.
Of course, health is a serious and often
grave matter, and humor delivered at
inappropriate times can be devastating,
insensitive, and crass. In this vein, certain
types of humor must be considered
off-limits—in particular cynical and
derogatory humor directed at the patient.
Unfortunately, some studies indicate that
avoiding these types of humor, including
“dark” and/or negative humor as a
coping mechanism for providers, can be
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more difficult than imagined.
29-31
Indeed,
negative humor can be passed down as
a sort of “hidden curriculum” and
perpetuated through many generations
of providers.
32
Within the bounds of appropriateness,
however, both humor and laughter can
be beneficial. For one, laughter shared
between the provider and patient
conveys a measure of trust and light-
heartedness. Furthermore, humor can
improve communication, as a joke can
signal a transition in the conversation
from the serious to more benign topics.
In general, medical providers do best
when acting cautiously and following the
patient’s lead. Knowing a patient well
and acknowledging any humor expressed
by him or her is recommended.
One additional unexplored field is the
possibility of using laughter “therapy” as
a means of sparking a more creative
approach to lifestyle change. Depressed
mood has been shown to be associated
with decreased physical activity and
weight gain in several societies. A recent
survey of roughly 1500 Israelis
33
used
logistic regression and showed that less
exercise and more weight was correlated
with depressive symptoms after adjusting
for confounders, although whether the
direction of the correlation is such that
mood causes the decrease in activity or
vice versa is unclear. Given that laughter
and humor is a key element to happiness
and is often used as a therapeutic tool
for depression,
7,34
both traditionally and
more recently in the form of “Laughter
Yoga” exercises mentioned above,
27,28
it
could potentially be used to counteract
the effects of depression and aid new
approaches to lifestyle change. More
recently, laughter and humor are being
used in geriatric care of patients with
dementia,
35
resulting in a positive climate
that could also potentially be fertile
ground for instituting lifestyle changes.
The Laughter
Prescription: A
Speculative Template
One method for putting laughter into
practice is to discuss laughter with the
patient during a visit. Providers can ask,
“What has made you laugh recently?” or
“How often do you laugh?” Inquiring
about laughter opens the door to light
heartedness and also could lead to
counseling on laughter and sharing the
latest research with the patient. More
important, it allows the provider to
determine what the patient finds funny,
thereby allowing the provider to tailor
recommendations to better fit the
patient’s needs and preferences. This also
contains the potential to deepen the
therapeutic relationship between patient
and provider. Put together with a more
structured approach, the health care
provider could consider prescribing
laughter to patients.
The MCET theory states that it may be
enough for patients to simply self-induce
the physical act of laughing in order to
gain positive benefits. Therefore,
prescribed laughter may be very helpful
in that all patients—even those
potentially unwilling to seek out comedy
or humor—can still engage in laughter
and derive benefits from it. There are
laughter yoga classes and videos
available online and even courses
offered at local recreations centers. If a
patient fails to benefit from the therapy,
then very little—if anything—is lost in
the attempt, as there are no side effects.
As such, adding in a brief 1-minute
conversation on laughter may represent
an additional fast, inexpensive, and
no-risk tool in the physician’s toolbox.
We propose that laughter prescriptions
might contain detailed information as to
the frequency, intensity, time, and type of
laughter (forming the useful mnemonic
“FITT”), much like pharmacological
prescriptions and exercise prescriptions.
This format aims to give patients clear
and easy-to-remember guidelines. It is
also a way to present laughter in a
serious manner. When prescribing
laughter, it would be of utmost
importance to individualize the
recommendations, taking into
consideration the patient’s own sense of
humor and willingness to engage in new
activities, such as laughter yoga.
An example of a laughter
prescription:
(F) Frequency: once a week
(I) Intensity: belly laughing
(T) Time: 30 minutes
(T) Type: your favorite sit-com
Laughter prescriptions remain largely
speculative, but existing research
indicates that efficacious laughter
“treatments” typically occur once a week
or less, for 30 to 60 minutes.
36
Nevertheless, shorter frequencies and
times, such as individual sessions as
short as 20 minutes, can still have a
positive impact.
18
Intensity remains an
open-ended question. It remains unclear
how much, or with what amount of
enthusiasm, one’s laugh leads to
emotional and physical benefits. Type is
the most variable factor of all. Again,
tailoring recommendations to what the
patient finds funny is an important part
of creating an effective prescription.
Furthermore, whether or not humor is
even needed to generate laughter (eg,
laughter yoga instead of watching
comedies) is up to the individual patient.
Another consideration is the idea of
group laughter, or laughter shared among
other people. Although most studies look
at the impact on one’s body through the
use of a humorous cartoon, in reality this
is only a small aspect of all the stimuli
that humans find amusing. Social laughter
often occurs in a situation with a stand-up
comedian. One functional magnetic
resonance imaging study looking at the
effect of stand-up comedians found that
clips considered humorous activated
reward centers in the brain.
37
Another
study from Israel looked at the effect of
humorous videos on schizophrenic
inpatients and found an improvement in
patient’s psychopathology, mood, and
mental status.
38
A randomized controlled
trial done in Japan, which allocated 27
individuals older than 60 to weekly
120-minute group laughter-with-exercise
sessions over 3 months, found an increase
in self-rated health as well as in objective
bone mineral density, and a decrease in
HbA1c levels,
39
suggesting that group
laughter sessions may be a way to
encourage the elderly to exercise.
However, it is currently unknown the
extent to which group laughter provides
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different benefits compared to laughing
on one’s own.
There are barriers to implementing
laughter therapy into one’s practice.
Finding the time to discuss laughter,
even just a 1-minute conversation, is
understandably challenging. Giving a
laughter prescription to patients
suffering from depression and dementia
could also be difficult. Significant life
stressors, such as a recent death in the
family, moving to a new home, being
fired from a job, and so on,
understandably make people feel
unwilling or unable to laugh; however,
laughter might still prove to be effective
medicine in these situations. In such
cases, it might take social support from
friends and family in order to help the
patient to engage in laughter. Thus, like
many lifestyle behaviors, it is likely best
if the environment and the people
closest to the patient are on board with
the laughter prescription in order for it
to be successful long term.
Conclusion
While it is well known that both
laughter and humor can have deep and
long-lasting psychological effects, it is
only recently that our knowledge of the
physiologic effects of laughter has grown.
This modern change has been in no small
part driven by the practices of laughter
yoga and similar self-induced, or
simulated, forms of laughter. Whereas
laughter and humor were once thought of
as nearly interchangeable, laughter is now
a distinct physical action that can be
effective on its own. Currently, research is
indicating that the physical act of
laughing, even without humor, is linked
to chemical changes in the body that
potentially reduce stress and increase pain
tolerance. Understanding the distinction
between spontaneous and simulated
laughter is likely to become a stronger
point of emphasis moving forward.
The United States is presently straining
under the weight of rapidly increasing
medical costs. Although there are
limitations to the current medical
literature on laughter, enough evidence
indicates that laughter may be employed
as part of our basic armamentarium to
help prevent diseases, reduce costs, and
ensure a healthier population. While
more research must be done, it is also
important to acknowledge there is not
much to lose in laughing. With no
downsides, side-effects, or risks,
perhaps it is time to consider laughter
seriously.
Acknowledgments
The authors would like to thank David Roberts, MD, for his
invaluable expertise and assistance in preparing this article for
publication.
AJLM
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