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EFFECT OF LAUGHTER YOGA ON PULMONARY REHABILITATION IN
PATIENTS WITH CHRONIC OBSTRUCTIVE PULMONARY DISEASE
ATSUHIKO FUKUOKA, MASAHIDE UEDA, YUTAKA ARIYAMA, KAZUNORI IWAI.
YOSHIRO KAI and MrKIKAZU KUNIMA TSU
Department of Internal Medicine, Yoshino -cho National Health Insurance Yoshino Hospital

MASANORI YOSHIKA WA, HIROKI UYAMA, KOICHI TOMODA and HIROSHI KIMURA
2"J Department of Internal Medicine, Nara Medical University
Received March 16, 2016

Abstract
Objective : To evaluat e the clinical usefulness of laughter yoga for patients with chronic
obstructive pulmonary disease (COPD) in a pulmonary rehabilitation setting.
Design : Pilot study, with randomization of participants.
Setting: This study was conducted by the Yoshino-cho National Health Insurance Yoshino
Hospital Department of Internal Medicine.
Participants : Stable outpatients with COPD (7 men and 1 woman, age 64 to 84 years)
participated in the pulmonary r ehabilitation progr am during a 2-week period.
Intervention : The patients were divided into two groups base d on a sealed envelope
randomization method. The laughter yoga group had a 10-min laughter yoga session before
exercise training. Patients in both groups had exercise training, educational progr ams, lungphysiother apy, and nutrition counseling.
Outcome Measures : He alt h-relate d qualit y of life using the St . George's Respir ator y
Questionnaire (SGRQ) and the Medical Research Council (MRC) Health Survey Short Form 36item (SF-36), depression scores using the Self-rating Depression Scale (SDS), anxiety scor es
using State-Tr ait Anxiety Inventory (STAI), and spirometry, the 6-minute walk test and mMRC
dyspnea scale results wer e evaluated before and at 2 weeks after the progr am in both groups.
R esults : There were significant improvements in the SGRQ impacts domain and the SF-36
general health domain in the laughter yoga group, while the SF-36 physical functioning domain
significantly improved in the control group. SDS and STAI result clid not significantly change
in either group. Spirometry, the 6-minute walk test, and MRC dyspnea scale results did not
significantly change in either group.
Conclusion : Laughter yoga may improve the psychological quality of life in patients with
COPD.
Key words : chronic obstructive pulmonary disease, pulmonary rehabilit ation, laughter yoga, psychologicalquality of life, depression, anxiety

(12)Atsuhiko FUKUOKA et al.

Introduction
Chronic obstructive pulmonary disease (COPD) is a worldwide clinical burden 1121. It is
associated with high mortality31 and deterioration of quality of life41 • COPD is a disease withmultiple comorbidities, and the updated Global Initiative for Chronic Obstructive Lung Disease(GOLD 2015) stresses the importance of treating comorbidities in patients with COPD11. Twoof the most common and least-treated comorbidities of COPD are anxiety and depression51, but
only a few prospective studies have addressed the diagnosis and management of anxiety anddepression, or have determined their impacts on health status among patients with COPD.
Furthermore, only a very small number of studies have evaluated therapeutic approaches toanxiety and depression in COPD patients6171•
Laughter is a behavior commonly related to positive emotion in human beings. Laughter isthought to be good for health, but the clinical application of laughter is challenging. Laughter
yoga is an exercise that combines laughter with yoga breathing. It has become a worldwide
health movement. with more than 10000 laughter clubs spread throughout numerous countries81.
Laughter yoga originated with Dr. Madan Kataria, in 1995, in Mumbai, India. It does not require
any specific inducer for laughter. Instead, participants may begin by feigning laughter until
they begin to laugh mirthfully. We believed that laughter yoga might help to relieve the anxiety
or depressive symptoms associated with COPD. Therefore, we performed a small, randomized
pilot study to investigate the effect of laughter yoga during a pulmonary rehabilitation programin patients with COPD.
To our knowledge, this is the first report of preliminary prospective randomized study oflaughter yoga for COPD patients.

Materials and Methods
Participant: The participants were stable COPD patients from our outpatient clinic. The
patients were enrolled in a pulmonary rehabilitation progr am. All patients who participated in
the study gave written informed consent. Inclusion criteria were forced expirator y volume in 1
second% predictive value (FEV1%) < 0.7 and FEV1%pred < 0.8, which are the GOLD 2 criteria.
Patients with severe heart disease, neuromuscular disease, or dementia were excluded. The
study participants were divided randomly using a sealed-envelope method into two groups: thelaughter yoga (LY) group and control group, which consisted of patients who participated inpulmonary rehabilitation without laughter yoga. All participants were enrolled in the pulmonary
rehabilitation program for 2 weeks. There were 5 patients in the LY group and 3 in the control
group. The clinical trial was approved by the Yoshino-cho National Health Insurance Yoshino
Hospital ethics committee.
Assessment instruments: Base-line characteristics were assessed through a detailed
questionnaire analysis of symptoms, age, smoking history, and diet. Height and body weight
were measured. Spirometric analysis (MINATO Autospiro AS 507) was used t o assess
slow vital capacity (VC), forced vital capacity (FVC), and forced expiratory volume in one

EFFECT OF LAUGHTER YOGA ON PULMONARY REHABILITATION IN
PATIENTS WITH CHRONIC OBSTRUCTIVE PULMONARY DISEASE(13)second (FEV1) using the Japanese Respiration Society (JRS) standard technique 91. Depressive
symptoms were assessed by Self-rating Depression Scale (SDS) 101 and anxiety symptoms wereassessed by the State-Trait Anxiety Inventory (ST AI) 111 for anxiety. The ST AI measures
two aspects of anxiety: state anxiety is short term anxiety induced after a precipitating event
and, trait anxiety is characteristic anxiety by nature. Health-related quality of life (QOL) was
assessed by the Medical Research Council Health Survey Short Form 36-item (SF-36) 12>141, andthe St. George's Respiratory Questionnaire (SGRQ) 151. The SF-36 is a generic instrument for
QOL surveys, and the SGRQ is a disease-specific instrument for r espiratory failure.
Exercise capacity assessment was done on the basis of the 6-minut e walk test (6MD)
according to the manual for respiratory rehabilitation of the Japanese Society for Respiratory
Care and Rehabilitation 161.
Intervention: All participants underwent comprehensive pulmonary rehabilitation (PR), which
included a PR conference once a week. The exercise intensity was low to medium. There were
five patient education sessions provided by a nurse using video lectures in a 2-week PR period.
Drug education or nutritional education was offered when necessary. The patients in the LY
group had 10 min of laughter yoga before a standard PR exercise training session. The laughter
yoga sessions involved the following steps:· Deep breathing (expiration-inspiration-expiration), 3 times. After inspiration a 3-second breathhold, followed by expiration with laughter.
· Parallel hand clapping with full expanded finger-to-finger and palm-to-palm contact; Kataria
has explained that this stage stimulates acupressure points in the hands to increase energy
levels. This clapping is carried out rhythmically, i.e., 1-2, 1-2-3.
·Laughter activities such as hand-shake laughter, wherein participants are to shake each other's hands and laugh together. An important point of this step is eye contact; the participants areencouraged to maintain eye contact and laugh together.
· The leader signals the end of the laughing activity by clapping and calling HO-HO HA-HAHA, and the participants stop their laughter.
· The session covers 3 to 5 activities held over about 10 minutes.
· Cool down at the end of these session by deep breathing.
Data analysis: T he data wer e analyzed using Stat View version 5.0 (SAS Institute Inc.) for
Windows. Descriptive statistics were reported in tables and as mean ± standard deviation or
frequency and percentage values. Main outcomes wer e presented as box plot gr aphs. Analysesof pre-post comparisons were performed using in Student's t-test and p-values of ~ 0.05 wereconsidered significant.

Results
Patients characteristics are shown in Table 1. There were 5 patients in the LY group and3 patients in the control group. There were no significant differ ences in age, body mass index(BMI), VC, F EV1, 6MD, and modified MRC dyspnea scale between the two groups.

(14)Atsuhiko FUKUOKA et al.
Table 1. Patient characteristics in 8 COPD patients
Participants(n=8)

group ( n=S)

Laughter yoga

Control group(n=3)

p valueAge fyr]75.5±6.4

74.6 ±6.777.0 ±7.0

Male/Female

7/ 1

5/0

2/ 1

BMI fkg/m'J

21.0±4.8

21.7±1.719.8±8.5

VCfL)

2.54±0.59

2.58±0.30

2.47 ±1.00

FEV1 !L)

1.03±0.48

0.93±0.20

1.20±0.81

6MD Iml

325.4±90.3

336.4±113.6

307.0±44.3

ns

mM RC

2.86±0.69

2.75±0.5

3.00±1.0

ns

ns[Table 1 abbreviation]
BM!: Body mass index, VC:vita! capacity, FEV1 :forced expiratory volume in one second
6MD: &-minute walk test, mM RC: modified Medical Research Council dyspnea scale

Table 2. Questionnaire data befor e and after intervention
Laughter yoga group
Pre-Rehab
Post-Rehab

Control group
Pre-Rehab
Post-Rehab

p-value

SGRQ symptom52.7± 11.4

44.4±15.961.0± 10.659.3±16.2

ns/ns

SGRQ activity

70.6 ±18.9

68,0±20.6

70.7 ± 8.1

58.7±7.2

ns/ nsSGRQ impacts

37.3±14.7

28.6±9.5*

42.7 ± 6.4

41.3±9.0

0.023/ ns

SGRQ total

49.8±13.443.3±10.554.0± 4.4

49.7 ± 6.8

ns/ns

SF-36 PF45.0± 31.4

53.3 ±29.2

41.1 ± 12.1

46.7 ±11.5*

ns/ 0.010

SF-36 RP15.0±33.5

30.0±41.1

8.3± 14.4

0.0 ± 0.0

/ nsSF-36 BP64.2±27.5

55.4± 25.3

54.7± 15.855.7±24.5

ns/ns

SF-36 GH39.4±8.952.2±8.7*

40.7±9.844.0±9.6

0.016/ns

SF-36 VT51.0 ± 18.2

62.0 ± 14.8

50.0 ±8.7

54.5±15.0

ns/ns

SF-36SF

65.0±38.9

79.9±28.975.0± 21.7

66.7 ± 38.2

ns/ns

SF-36 RE

20.0±44.7

20.0±44.7

0.0 ± 0.0

0.0±0.0

ns/ ns

SF-36 MH56.0±26.8

72.0±16.5

54.7± 8.3

67.3±21.9

ns/ns

SOS

40.0±4.838.8± 9.940.7± 9.5*43.3±8.6

ns/ns

STAI(Stateamliety)38.6 ± 12.4

35.0 ± 10.4

44.3 ± 11.7

36.7 ± 6.1

ns/ns

STAI(Trait anxiety)33.8±5.431.2±8.6

41.0±13.0

34.3±2.9

ns/ ns* : p<O.OS[Table 2 a bbreviation]
PF: physical functioning, RP: role-physical, BP: bodily pa in, GH: general health, Vf:vitality, SF: social fu nctioning, RF: role-emotional, MH: mental health.

I

60

55

p=O,D93

p=O.OlO

I l

100
90

50

• 45

11 Laughter yoga

§40

D Control

g3s
~30

25
20
15 L_------~=----SGROimp
SGRO imp

Pre-rehab

Post-rehab

80
70
60
~ 50
~
'1' 40
:!;
30
20
~

D

HLaughteryoge
Cootrol

CJ D

toSF36 PF

Pre-re hab

Fig. 1. QOL (SGRQ impacts dom ain) ch a nge
before and after intervent ion. LY group improved
significantly, compar ed to the control group.

I

SF36 PF
Post-re hab

F ig. 2. QOL (SF -36 PF domain) change before
and after inter vention. Control group im proved
significantly, compared to the LY group. The QOLof the control group was not different from that of
the L Y group.

EFFECT OF LAUGHTER YOGA ON PULMONARY REHABILITATION IN
PATIENTS WITH CHRONIC OBSTRUCTIVE PULMONARY DISEASE

,I

. I

p,0.0 16 l"·' · I!~j.o•o !jl l oti-a
:~
"

v;

_j

L_ n.s.

Vi :~~

Ln.s.__j

10

Pre-Rehab

Pre-Rehab

Post-Rehab! lJ •'"=il~
L
n.s.

20

Pre-Rehab

IJLaughter yoga

Post-Rehab

SF-36 Vitality

SF-36 General Health

:~; :

(15)

ocontrol

~

_j

3-C

I

Post-Rehab

SF-36 Mental HealthFig. 3. Change in psychological QOL domains before and after
intervention for 3-A. SF-36 General Health, 3-B. SF-36 Vitality, 3-C.
SF-36 Ment al Health. In 3-A. only GH is significantly improved in
the LY group.

.RIEJ: [ "·' -,

1:
0

ll

VI

:

LJ
L

P=0.094_j.~JJ..n, ..
.EJ
Pre-Rehab

Post·Rehab

SOS: I"~~ ~o•~j :: ..I.. D
35

VI

..

c=J

:

" '---,-,..,,-h, , - , -.,_,,-h,bSTAI (Stat e anxiety)llaughter yoga

0Cont rol1"~- ,

1~J5·
"':

"

Pre-Rehab

Ln.s. :=_j

~
4-C

I

Post-Rehab

STAI (Trait anxiety)Fig. 4. Depressive state and anxiety before and aft er intervention
for 4-A. SDS score, 4-B. ST AI (State anxiety) score, 4-C. STAI (Trait
anxiety)' score. There is no significant change in any data pre andpost intervention.

The questionnaire data before and after intervention for each group are shown in T able 2.
There was significant improvement in the SGRQ impacts domain in the LY group (37.3 ± 14.7
to 28.6 ± 9.5. p = 0.023) (Fig. 1). but no significant change was noted in the control group. The
SF-36 general health domain also improved significantly in the LY group (39.4 ± 8.9 to 52.2 ±
8.7, p = 0.016). but not in the control group (Fig. 3-A). The SF-36 physical functioning domain
showed an improvement in both groups, but the change did not reach statistical significance inthe LY group (45.0 ± 31.4 to 53.3 ± 29.2, p = 0.093, vs. 41.1 ± 12.1 to 46.7 ± 11.5. control group,p = O.OlO)(Fig. 2).
There were no significant changes in SDS and STAI outcomes fr om baseline to postrehabilitation (Fig. 4) in either group.
Pre- and post-intervention, respiratory function, activity, and dyspnea scales are shown in
T able 3. VC and FEV1 data did not change significantly in either group, and ther e were no
significant changes in 6MD in either group, although the improvement in the control group was
somewhat larger than that in the LY group. The dyspnea scale had a tendency of improvement

Atsuhiko FUKUOKA et al.

(16)

Table 3. Respiratory function, activity, and dyspnea scale
before and after intervention
Laushter yos:a Grou~
Post-Rehab

Pre-RehabControl !i,!;rDUE!
Pre-Rehab
Post-Rehab

p-value

VC (l)

2.58±0.30

2.59±0.28

2.47 ±1.0 1

3.06±0.09

ns/ns

FEV1 (l]0.93±0 .20

0.88±0.22

1.20±0 .81

1.69±0.52

ns/ns

Ill

1.79± 0 .16

1.99±0.47

1.71±0.84

1.97±0.50

ns/ns

6MD (m]

336.4±113.6

339.6±128.1

307.0±44.2

337.7±23.7

ns/ns

mM RC

2.75±0.50

2.00±0.0

3.00±1.00

2.67±0.58

ns/ nsIC(Table 3 abbreviation]
VC: vital capacity, FEV1: forced expiratory volume in one second, IC: inspiratory
capacity, GMD: 6-minute walk test, mM RC: modified Medical Research Council

dyspnea scale

in both groups, particularly in the LY group (2.75 ± 0.50 to 2.00 ± 0.0, p = 0.057).

Discussion
In recent years, more attention has been focused on the many comorbid conditions inpatients with COPD 11• The GOLD 2015 and other guidelines emphasize the importance of thetreatment for these comorbid diseases. Among the comorbidities, depression and anxiety areespecially difficult to treat51• Depression is reported in 5.5 to 44.4% of patients with COPD171'231•
The GOLD 2015 recommends standard medical therapies for depression and anxiety in patientswith COPD, but this therapy is often not effective for these patients. Yohannes et al.61 reported
a trial of fluoxetine in depressive patients with COPD. They found that patient compliancewith the antidepressants was poor. There were 7 out of 57 patients (12%) who completed a
6-week course of fluoxetine, and 4 (7%) were fluoxetine responders. It was also r eported inanother study comparing COPD and non-COPD patients that 52.8% of the COPD patients wereable to complete a 3-month course of antidepressants, vs. 63.2% of non-COPD patients 71, andJordan et al. 241 have reported that there was no significant improvement in hospitalization andin all-cause mortality in COPD patients treated for depression in accor dance with guideline
recommendations.
On the other hand, it is widely known that pulmonary rehabilitation is effective to relieve
depression and anxiety for patients with COPD 251· 261• However depressed COPD patients
may avoid attending pulmonary rehabilitation or have a greater tendency to drop out 271. It is
possible that by enhancing the impression of these programs as a good life event, patients withdepression and anxiety might be more likely to continue.
The old proverb "laughter is the best medicine" had gained empirical support in various
fields of medicine and health care. Norman Cousins, a well-known journalist in the US, publishedan article in the New England Journal of Medicine describing his successful pain relief forankylosing spondylarthritis, wherein he reported that 10 minutes of laughter give him atleast two hours of pain-free sleep 281, and more recently it was determined that laughter could
activate NK activity in various situations 291•
Meanwhile, Surwit et al. have reported that negative emotion is associated with increased
blood sugar levels 301, while Hayashi et al. have r eported that laughter lowered postprandial

EFFECT OF LAUGHTER YOGA ON PULMONARY REHABJLITATION IN
PATIENTS WITH CHRONIC OBSTRUCT IVE PULMONARY DISEASE(17)

blood glucose levels in patients with type 2 diabetes mellitus after 40 min of watching Manzai,a Japanese cross-talk comedy 31'. Other studies have also indicated that laughter is effective inameliorating type 2 diabetes mellitus 32· 33'.
It has also been well-established that negative emotional states increase the risk for
cardiovascular disease, and Sugawara et al. 34' have suggested that mirthful laughter had abeneficial effect on carotid arterial compliance, and that the effect was sustainable for 24 hours.
Although all of these reports suggest the benefits of laughter or positive emotions, almost all
studies concerning laughter have relied on comedy videos induce laughter in the test patients.
In routine clinical practice, it can be difficult to accumulate a sufficient variety of comedy videos
to maintain the interest of the patients.
As noted, Madan Kataria introduced laughter yoga in 1995, while he was practicing as afamily physician in Munbai, India. Laughter yoga combines laughter with a yoga breathing
method. An advantage of laughter yoga is that it does not require an outside stimulate toinduce laughter. Laughter yoga has recently been mentioned in sever al reports. Shahidi et al.
found that the benefits of laughter yoga were equivalent to those of a group exercise programfor elderly depressed women 35'. and laughter yoga has also been credited as beneficial for
moderating heart rate variability, mood, and long-term anxiety among outpatients awaitingorgan transplantation 36'.
In this pilot study, laughter yoga provided signific ant improvements in the SGRQ
impacts domain and the SF-36 general health domain among COPD patients in a pulmonary
rehabilitation program. We believe that our finding that the SF-36 physical functioning domain
was significantly improved only in the control group was due to the fact that the LY group had
slightly higher baseline scores for this parameter, which may have influenced the extent of thedifference in the change between the two groups befor e and after intervention.
Our results showed a worsening tendency in the SDS score among the control patients,
while there was a small (non-significant) decrease in these scores among the LY patients, andstate anxiety decreased in both groups, but not significantly. There was no significant change
in VC, FEV~o or 6MD in either group. Since it is generally known that an effective duration fora pulmonary rehabilitation program is over 6 weeks 37'. the short study period in this reportprobably influenced these results. Taking this into account, our new 6-week COPD outpatients
PR trial is under way. (Data was not shown in this paper.)The key to treating depression and anxiety in COPD patients remains elusive. If laughter
yoga can provide improved psychological QOL, it will be a useful addition to pulmonary
rehabilitation for COPD patients.
We know that this study has several limitations. First, the number of patients is very small.
We recently introduced an action plan for our pulmonary rehabilitation program that would
have forced the study protocol to change, so we stopped entry into this study.
Second. the SDS and ST AI scores did not change significantly, and this may be because
among the enrolled patients, who came from our general COPD outpatient population, thebaseline levels of depression and anxiety were lower than they would have been if we had
focused enrollment on COPD patients with known depr ession and anxiety. Laughter yoga isvery easy to perform, and may be beneficial for COPD patients with depression and anxiety.

(18)Atsuhiko FUKUOKA et al.

Further studies with longer trial periods and greater numbers of COPD patients with known
depression or anxiety should be encouraged.

Conclusions
The findings from this study reveal that laughter yoga may improve the psychologicalquality of life in patients with COPD. More studies need for establishing clinical usefulness oflaughter yoga. We are very keen to improve the quality of life of patients with COPD using
pulmonary rehabilitation with laughter yoga.

Acknowledgments
We would like to acknowledge the contribution of all staff of the Yoshino-cho National Health
Insurance Yoshino Hospital, especially Koji Kamogawa, Kimi Nishibayashi, Chizuru Imada, andKeiko Matsusaka. They have given us a lot of support through the laughter yoga activity.

Conflict of interest
The authors have no conflict of interest to be reported in relation to this study.

References
1) Decramer M, Vestbo J, Vestbo J et al. The Global Strategy for the Diagnosis, Management and Preventionof COPD, Global Initiative for Chronic Obstructive Lung Disease (GOLD) 2015, http://www.goldcopd.org/.
April. 29, 2015.
2) Lopez AD, Shibuya K, Rao C, et al. Chronic obstructive pulmonary disease: current burden and future
projections. Eur Respir J 2006; 27: 397-412, 2006.
3) Mathers CD and Loncar D. Projections of Global mortality and burden of disease from 2002 to 2030. PLoS
Med 2006; 3: e442.
4) Peruzza S, Sergi G, Vianello A. et al. Chronic obstructive pulmonary disease (COPD) in elderly subjects:
impact on functional status and quality of life. Respir Med 2003; 97: 612-617.
5) Maurer ]. Rebbapragada V, Borson S, et al. Anxiety and depression in COPD. Chest 2008; 134: 43S-56S.
6) Yohannes AM, Connolly MJ. Baldwin RC. A feasibility study of antidepressant drug ther apy in depressed
elderly patients with chronic obstructive pulmonary disease. Int J Geriatr Psychiatry 2001; 16: 451-454.
7) Pirraglia P A. Charbonneau A. Kader B. et al. Adequate initial antidepressant tr eatment among patientswith chronic obstructive pulmonary disease in a cohort of depressed veterans. Prim Care Companion J Clin
Psychiatry 2006; 8: 71-76.
8) Laughter yoga Global Movement for health, Joy & World peace, http:// www.laghteryoga.org/ . April. 29,
2015.
9) Japanese Respiration Society, eds. Guideline for lung function test - spirometry, flow-volume curve, diffusion
capacity of the lung-. Medical Review, pp2, 2004.
10) Zung WWK. A self-rating depression scale. Arch Gen Psychiatry 1965; 12: 63-70.

EFFECT OF LAUGHTER YOGA ON PULMONARY REHABTI.ITATION IN
PATIENTS WITH CHRONIC OBSTRUCTIVE PULMONARY DISEASE(19)11) Spielberger CD. Theory and research on anxiety: Anxiety and behavior. New York, Academic Press. 1966.
12) Fukuhara S, Bito S, Green J et al. Translation, adaptation, and validation of the SF-36 health survey for use
in Japan. J Clin Epidemiol1998; 51: 1037-1044.
13) Fukuhara S, Ware JE. Kosinski M et al. Psychometric and clinical tests of validity of the Japanese SF-36
Health Survey. J Clin Epidemio11998; 51: 1045-10533.
14) Fukuhara S, Suzukamo Y, Bito S et al. Manual of SF-36 Japanese version 1.2: Public Health Research
Foundation, Tokyo, 2001.
15) Jones PW, Quirk FH, Baveystock CM, Littelejohns P. A self-complete measure for chronic airflow limitation:the St. George's Respiratory Questionnaire. Am Rev Respir Dis 1992; 145: 1321-1327.
16) Japanese society for respiratory care and rehabilitation, eds. Manual for respir atory rehabilitation -Exercise
therapy - . Shorinsha, pp76, 2003.
17) Tze-Pin Ng, Mathew Niti, Wan-Cheng Tan, et al. Depressive symptoms and chronic obstructive pulmonary
disease. Effect on Mortality, Hospital Readmission, Symptom Burden, Functional Status, and Quality of Life.
Arch Intern Med 2007;167:60-67.
18) Schane RE, Woodruff PG, Dinno A et al. Prevalence and risk factors for depressive symptoms in persons
with chronic obstructive pulmonary disease. J Gen Intern Med 2008; 23:1757-62.
19) Bert LVD, Schemer T, Bor H. et al. The risk for depression comorbidity in patients with COPD. Chest 2009;135: 108-114.
20) De Voogd JN, Wempe JB, Koeter GH, et al. Depression symptoms as predictors of mortality in patients with
COPD. Chest 2009; 135: 619-625.
21) Omachi TA Katz PP, Yelin EH. Depression and health-r elated quality of life in chronic obstructive
pulmonary disease. Am J Med 2009; 122: 778.e9-778.e15.
22) Hayashi Y, Senjyu H. Iguchi A et al. Prevalence of depressive symptoms in Japanese male patients withchronic obstructive pulmonary disease. Psychiatry and clinical Neurosciences 2011; 65: 82-88.
23) Schnell K, Weiss CO, Lee T, et al The prevalence of clinically-relevant comorbid conditions in patients withphysician-diagnosed COPD: a cross-sectional study using data from NHANES 1999-2008. BMC pulmonary
Med 2012; 12: 26.
24) Jordan N, Lee TA Valenstein M, et al. Effect of depression care on outcome in COPD patients withdepression. Chest 2009; 135:626-632.
25) Garuti G, Cilione C, Dell'Orso D, et al. Impact of comprehensive pulmonary rehabilitation on anxiety anddepression in hospitalized COPD patients. Monaldi Arch Chest Dis 2003; 59: 56-61.
26) Paz-Diez H, Montes de Oca M, Lopez JM, et al : Pulmonary rehabilitation impr oves depression, anxiety,dyspnea and health status in patients with COPD. Am J Phys Med Rehabil 2006; 86: 30-36.
27) Keating A Lee A and Holland AE. What prevents people with chronic obstructive pulmonary disease from
attending pulmonary rehabilitation? A systematic review. Chr Respir Dis 2011; 8: 89-99.
28) Norman Causins. Anatomy of an illness (As perceived by the patient). New Engl J Med 1976; 296: 1458-1463.
29) Bennett MP, Zeller JM, Rosenberg L, et al. The effect of mirthful laughter on stress and natural killer cell
activity. Altern Ther Health Med. 2003; 9: 38-43.
30) Surwit RS and Sreatchneider MS. Role of stress in the etiology and treatment of diabetes mellit us.
Psychosomatic Medicine 1993; 55: 380-393.
31) Hayashi K, Hayashi T, Iwanaga S, et al. Laughter lowered the incr ease in postprandial blood glucose.
Diabetes Care 2003; 26: 1651-1652.

(20)Atsuhiko FUKUOKA et al.

32) Hayashi T, Urayama 0, Kawai K. et al. Laughter regulates gene expression in patients with type 2 diabetes.
Psychother Psychosom 2006; 75: 62-65.
33) Hayashi T. Tsujii S, Iburi T, et al. Laughter up-regulates the genes related to NK cell activity in diabetes.
Biomedical Research 2007; 28: 281-285.
34) Sugawara J. Tarumi T and Tanaka H. Effect of mirthful laughter on vascular function. Am J Cardiol 2010;
106: 856-859.
35) Shahidi M, Mojtahed A, Modabbernia A, et al. Laughter yoga versus group exercise program in elderly
depressed women: a randomized controlled trial. Int J Geriatr Psychiatry 2011; 26: 322-327.
36) Dolgoff-Kaspar R. Baldwin A, Scott Johnson M, et al. Effect of laughter yoga on mood and heart ratevariability in patients awaiting organ transplantation: a pilot study. Altern Ther Health Med 2012; 18: 53-58.
37) Japanese society for respiratory care and rehabilitation, eds. Manual for respiratory rehabilitation - Exercise
therapy - 2nd edition. Shorinsha, pp42, 2012.