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wileyonlinelibrary.com/journal/sms Scand J Med Sci Sports. 2018;28:1130–1138.
© 2017 John Wiley & Sons A/S.
Published by John Wiley & Sons Ltd
Accepted: 28 November 2017
DOI: 10.1111/sms.13029
ORIGINAL ARTICLE
Yoga training modulates adipokines in adults with high- normal
blood pressure and metabolic syndrome
Rashmi Supriya1
|
Angus P. Yu2
|
Paul H. Lee3
|
Christopher W. Lai1
|
Kenneth K. Cheng1
|
Sonata Y. Yau4
|
Lawrence W. Chan1
|
Benjamin Y. Yung1
|
Parco M. Siu2
1Department of Health Technology and
Informatics,Faculty of Health and Social
Sciences,The Hong Kong Polytechnic
University, Kowloon, Hong Kong, China
2School of Public Health,Li Ka Shing
Faculty of Medicine,The University of
Hong Kong, Pokfulam, Hong Kong, China
3School of Nursing,Faculty of Health
and Social Sciences,The Hong Kong
Polytechnic University, Kowloon, Hong
Kong, China
4Department of Rehabilitation
Sciences,Faculty of Health and Social
Sciences,The Hong Kong Polytechnic
University, Kowloon, Hong Kong, China
Correspondence
Parco M. Siu, School of Public Health, The
University of Hong Kong, Pokfulam, Hong
Kong, China.
Email: pmsiu@hku.hk
Funding information
Hong Kong Research Grants Council Hong
Kong Ph.D. Fellowship Scheme, Grant/
Award Number: RTVX PF13-11753; Hong
Kong Polytechnic University Research
Fund, Grant/Award Number: 1-ZE17; The
University of Hong Kong Seed Fund for
Basic Research
Metabolic syndrome (MetS) is associated with diabetes mellitus and cardiovascular
diseases. Our previous study indicated that people with MetS showed a decrease in
waist circumference and a decreasing trend in blood pressure after 1- year yoga. This
study investigated the effect of yoga on MetS people with high- normal blood pres-
sure by exploring modulations in proinflammatory adipokines (leptin, chemerin, vis-
fatin, and plasminogen activator inhibitor- 1 or PAI- 1) and an anti- inflammatory
adipokine (adiponectin). A total of 97 Hong Kong Chinese individuals aged
57.6 ± 9.1 years with MetS and high- normal blood pressure were randomly assigned
to control (n = 45) and yoga groups (n = 52). Participants in the control group were
not given any intervention but were contacted monthly to monitor their health status.
Participants in the yoga group underwent a yoga training program with three 1- hour
yoga sessions weekly for 1 year. The participants’ sera were harvested and assessed
for adipokines. Generalized estimating equation (GEE) was used to examine the in-
teraction effect between 1- year time (pre vs post), and intervention (control vs yoga).
GEE analyses revealed significant interaction effects between 1- year time and yoga
intervention for the decreases in leptin and chemerin and the increase in adiponectin
concentration in the sera examined. These results demonstrated that 1- year yoga
training decreased proinflammatory adipokines and increased anti- inflammatory adi-
pokine in adults with MetS and high- normal blood pressure. These findings support
the beneficial role of yoga in managing MetS by favorably modulating adipokines.
KEYWORDS
adipokine, high blood pressure, hypertension, metabolic syndrome, mind-body exercise
1
|
INTRODUCTION
Metabolic syndrome (MetS) is a clinically significant predic-
tor of all- cause and cardiovascular mortality. MetS represents
a cluster of metabolic abnormalities including central obe-
sity, high blood pressure, dyslipidemia, hypertriglyceridemia,
and hyperglycemia. Central obesity and insulin resistance
are considered important underlying contributors to MetS.1
Furthermore, some researchers believe that hypertension
might be another chief contributor to MetS as hyperten-
sion increases the risk for obesity and insulin resistance.2,3
Approximately 65%- 75% of hypertensive individuals are
obese, and 50% of hypertensive individuals are insulin-
resistant.4 Notably, it has been shown that the prevalence of
elevated blood pressure or hypertension among people with
MetS could be as high as 85%.3 Thus, it has been proposed
that blood pressure control might be an important strategy in
reducing the risk of MetS in healthy individuals.
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SUPRIYA etAl.
Lifestyle modification has been suggested to be the key-
stone for successful management of MetS.5,6 Yoga is a blend
of physical exercise, controlled breathing, and relaxation prac-
tice. Hatha yoga, a commonly practised yoga stream, consists
of asana (control of postures) and pranayama (manipulation
of respiration). Yoga appears to have an antihypertensive ef-
fect as well as a positive impact on self- rated quality of life.
Improvements of MetS risk factors in middle- aged and older
adults have been demonstrated to be associated with yoga in-
tervention7. One- year yoga training was shown to exert ben-
eficial effect on reducing abdominal obesity and tended to
decrease blood pressure in MetS people.7 Moreover, a short-
term intensive yoga program (90 minutes/day for 15 consec-
utive days) has also been demonstrated to cause favorable
changes in body mass index, waist and hip circumference,
total cholesterol, postural stability, and handgrip strength.8
Indeed, yoga exercise has been shown to decrease stress,
reduce depression and anxiety, and increase perceived self-
efficacy in healthy individuals. The reduction in stress has
been proposed as one of the potential underlying mechanisms
explaining the benefits of yoga exercise.9 Intriguingly, a
cross- sectional study comparing the stress hormones between
novice and expert yoga practitioners demonstrated that leptin
was lowered and the ratio of adiponectin- to- leptin was dou-
bled in experts when compared to novice yoga practitioners.9
An epidemiological link between adiposity and hyperten-
sion has been illustrated. Adipose tissue is a heterogeneous
organ comprised of subcutaneous and visceral adipose tis-
sue. The incidence of hypertension has been reported to
be strongly associated with increased visceral adiposity.10
Compared to subcutaneous adipose tissue, visceral fat is more
sensitive to lipolysis and secretes higher amounts of inflam-
matory cytokines such as PAI- 1,11 visfatin,12 and chemerin.13
In addition to visceral adipokines, subcutaneous adipokines
have been correlated with hypertension. Subcutaneous ad-
ipose depot secretions of leptin and adiponectin might be
useful in the prediction of hypertension.14 The progressive
interaction between proinflammatory and anti- inflammatory
adipokines is commonly thought to play a significant role in
the developmental process of systemic metabolic abnormali-
ties. Therefore, the understanding of the equilibrium and bal-
ance of adipokines (ie, pro- vs anti- inflammatory adipokines)
in response to lifestyle components such as physical exercise
are critically needed for the new development of regimens to
combat MetS and other metabolic disorders.
Yoga reduces MetS risk factors15 as well as inflam-
matory adipokines.16,17 Our previous study indicated that
participants with MetS showed a significant decrease in
waist circumference and a decreasing trend in blood pres-
sure (P = .067) with moderate effect size after 1- year of
yoga intervention.7 Therefore, we hypothesized that yoga
training would induce a favorable modulation of the ad-
ipokine profile by reducing the circulatory abundance
of proinflammatory adipokines and increasing anti-
inflammatory adipokines in adults with MetS and high-
normal blood pressure.
2
|
METHODS
2.1
|
Study design and subject recruitment
This study was a follow- up to our previous randomized
controlled trial in which Chinese participants aged between
30 and 80 years who were diagnosed with MetS accord-
ing to the diagnostic guidelines of the National Cholesterol
Education Program (NCEP) Adult Treatment Panel (ATP
III) criteria underwent a 1- year yoga intervention program
in Hong Kong. Individuals with MetS were defined as
having three or more of the following characteristics: (a)
central obesity (waist circumference ≥ 90 cm for Asian
males or ≥ 80 cm for Asian females); (b) elevated blood
glucose (fasting glucose level ≥ 5.5 mmol/L); (c) elevated
blood pressure (systolic pressure ≥ 130 mm Hg or dias-
tolic pressure ≥ 85 mm Hg); (d) elevated plasma triglyc-
erides (triglyceride level ≥ 1.7 mmol/L); and (e) a low
level of high- density lipoprotein cholesterol (HDL- C; level
≤ 1.03 mmol/L for males or ≤ 1.3 mmol/L for females).
Participants were randomly allocated into groups using a
computer program.
Participants having symptomatic heart or lung disease,
pulmonary illness, severe rheumatoid arthritis or osteoarthri-
tis, dementia or mental disorder, previous stroke, severe car-
diovascular illness, major orthopedic problems in the lower
back, neuromusculo- skeletal illness, and pelvis or lower ex-
tremities were excluded. Participants who were on drug ther-
apy treating metabolic abnormalities, regular tobacco users,
wheelchair users, immobile, with physical conditions not
appropriate for yoga exercise were excluded. Additionally,
participants who exercised at moderate- to- vigorous inten-
sity at least 30 minutes per session regularly (3 or more
days a week) were also excluded. All the experimental pro-
cedures received human research ethics approval from The
Hong Kong Polytechnic University (ethics approval number:
HSEARS20090820001 and HSEARS20160810001).7
In this study, we specifically selected 97 blood samples of
participants (control n = 45, yoga n = 52) who had MetS spe-
cifically with high- normal blood pressure (systolic pressure
≥ 130 mm Hg or diastolic pressure ≥ 85 mm Hg) from the
pool of 182 archived blood samples from our previous study.
The samples from control and yoga intervention group were
selected from two time points: Pre (baseline measurement at
the beginning of the study) and Post (the measurement upon
accomplishment of the 1- year experimental period). Attrition
rate in the study was 4.4% as some participants quitted the
study due to personal reasons and some never showed up
after the recruitment.
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SUPRIYA etAl.
2.2
|
Yoga intervention
Participants in the control group were not given any in-
tervention but were contacted monthly to monitor their
health status. Participants in the yoga group attended
three yoga sessions weekly for 1 year. Each 60- min ses-
sion consisted of a 10- min warm- up, 40 minutes of hatha
yoga practice, and a 10- min cool- down that consisted of
a breathing and relaxation exercise.7 Yoga classes were
conducted in a small group (~10 participants) by certified
yoga instructors. All participants were requested to adhere
to their usual daily dietary intake and physical activities
throughout the one- year experimental period. As an incen-
tive, participants were offered a supermarket coupon upon
completion of the study. Participants in the yoga group
who attended less than 70% of the classes were excluded.7
The training protocol of the yoga exercise program is
shown in Table 1.
2.3
|
Determination of MetS risk factors
Participants were assessed by trained research personnel
for MetS diagnostic parameters including blood pressure,
waist circumference, fasting glucose, triglycerides, and
HDL- C. The blood pressure measurement was performed
on the right arm of the subject after a 5- min rest in a sit-
ting position. Using an appropriate- sized cuff, systolic and
diastolic blood pressures were measured by an electronic
blood pressure monitor (Accutorr Plus, Datascope) over
the brachial artery region with the arm supported at heart
level. Waist circumference was measured on the bare skin,
midway between the lowest rib and the superior border of
the iliac crest, using an inelastic measuring tape. Venous
blood samples were harvested by certified phlebotomists
after participants fasted overnight. Blood glucose, triglyc-
erides, and HDL- C concentrations were measured by an
accredited medical laboratory using commercial test kit
Sanskrit name of
asana
English name of
asana
Sanskrit name of
asana
English name of
asana
Marjaryasana to
Bitilasana
Cat to cow stretch Balasana Child pose
Adho muha
svanasana
Downward dog Setu bandhasana Bridge pose
Utthitaashwa
sanchalanasana.
High lunge Supta
padangusthasana
Reclining big toe
pose
Uttanasana Standing forward
bend
Ananda balsana Happy baby pose
Spinal twist Matsyendrasana Virasana Hero pose
Uradva hastasana Upward salute Padangusthasana Finger and toe
weaving
Ukatassanna Chair pose Centering In cross- legged
position
Virabhadrasana Warrior pose Paripurna navasana Knees bend version
of boat pose
Utthita parsva
konasana
Side angle pose Vajrasana Thunderbolt pose
Utthita trikonasana Extended triangle
pose
Sukhasana). Easy pose
Vrksasana Tree pose Shavasana Corpse pose
Malasana Garland pose Eka pada bhekasana 1- leg frog pose
Eka pada
rajakapotasana
One- legged king
pigeon pose
Sputa baddha
konasana
Lying down bound
angle pose
Salambhasana Locust pose Uttitha hasta
padangustasana
Extended big toe
pose
Dandasana Staff pose Sputa padangusthana Big toe lying down
pose
Baddha konasana Bound angle pose Padangusthasana Big toe pose
Agnistambhasana Fire log pose Salabasana Locust pose
Gomukhasana Cow face pose Tadasana Mountain pose
TABLE 1 The yoga postures (in both
Sanskrit and English) practised in routine
training protocol for 1- year yoga
intervention group
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SUPRIYA etAl.
methods and an automatic clinical chemistry analyzer
(Architect CI8200, Abbott Diagnostics, USA).7 Systolic
blood pressure, diastolic blood pressure, fasting plasma
glucose, waist circumference, HDL- C, and triglycerides
were examined at baseline and at the end of the 1- year ex-
perimental period. Furthermore, the detailed explanations
about the methods used for the assessment of MetS risk
factors are described in our previous publication.7
2.4
|
Measurement of adipokines
Commercially available enzyme- linked immunosorbent assay
(ELISA) kits (Visfatin from BioVision; PAI- 1 and chemerin
from R&D; leptin and adiponectin from Thermo Fisher
Scientific, USA) were used to examine the concentrations of
adipokines in the serum samples according to the manufac-
turer’s instructions. The coefficients of variability (CV) for the
kit assays are as follows: visfatin (intra- assay: 4.4%- 8%, interas-
say: 8.2%), PAI- 1 (intra- assay: 6.8%, interassay: 7%), chemerin
(intra- assay: 3.9%, interassay: 7.3%), leptin (intra- assay: 3.9%,
interassay: 5.3%), and adiponectin (intra- assay: 3.8%, interas-
say: 5.5%). Measurements were performed in duplicates or trip-
licates by a single observer to minimize the observer variation.
2.5
|
Data analyses
Data are expressed as the means ± standard deviation. The gen-
eralized estimating equation (GEE) was adopted to examine the
interaction effect between 1- year time and the intervention, the
main effect of time, and the main effect of intervention on adi-
pokines and MetS risk factors. GEE was also used to examine
the interaction effect between 1- year time and the yoga interven-
tion on MetS risk factors after adjusting the age as a covariate.
Normality of the data was verified by the Shapiro- Wilk test. The
Mann- Whitney U test was performed to examine the baseline
differences in MetS risk factors, age, sex and the changes (post-
pre) in the MetS risk factors and adipokines between control and
yoga groups. The Chi- square test was performed to examine the
baseline differences in the categorical data. All statistical analy-
ses were performed using the Statistical Package for the Social
Sciences (SPSS) version 22 for Windows. Statistical signifi-
cance was indicated by P < 0.05. Our power analyses indicated
that the statistical power was >80% for most of the outcome
measures performed in this study including adiponectin, leptin,
chemerin, visfatin, diastolic blood pressure, and systolic blood
pressure.
3
|
RESULTS
3.1
|
MetS risk factors
No significant differences were observed in the MetS risk
factors, habitual physical activity level (as assessed by
international physical activity questionnaire or IPAQ), and
adipokines at the baseline assessment between control and
yoga groups (Table 2). Our analysis revealed that among all
the other MetS risk factors that were measured, the mean
change (ie, post- pre) in waist circumference was significantly
lower in the yoga group compared to the control group (−3.6
vs −1.4, P = .029) (Figure 1). The mean waist circumference
value was reduced by 4% in the yoga group and 2% in control
group (Figure 2F).
Further analysis revealed that there was no significant in-
teraction effect between time and intervention for diastolic
blood pressure, systolic blood pressure, high- density lipopro-
tein, triglycerides, fasting glucose, and waist circumference
in our examined MetS participants with high- normal blood
pressure (Figure 2). Of note, we also found no significant in-
teraction effect between time and intervention on MetS risk
factors in MetS participants with high- normal blood pressure
after adjusting for the age as a covariate. The main effect of
time was observed for systolic blood pressure (Wald Chi-
square test= 12.4, P < .001), diastolic blood pressure (Wald
Chi- square test= 6.3, P = .012), and waist circumference
(Wald Chi- square test= 4.4, P = .037) (Figure 2A,B and F).
3.2
|
Anti- and proinflammatory adipokines
Our results revealed significant differences in the mean
value of change (ie, post- pre) in adiponectin (−1.0 vs 1.3,
P < .001), PAI- 1 (0.9 vs 0.4, P = .03), chemerin (46.3 vs
−32.8, P < .001), and leptin (1.9 vs −6.7, P < .001) in the
control vs. yoga groups (Figure 3A- D). The mean value
of adiponectin levels in the yoga group was increased by
20.1% compared to a decrease of 15.5% in the control group
(Figure 4A). Moreover, the mean values of leptin, PAI- 1,
and chemerin were significantly decreased (26.5%, 6.5%, and
14.3%, respectively) in the yoga group compared to increases
in each variable (9%, 13.5%, and 21%, respectively) in the
control group (Figure 4B,C and D).
Our further analysis revealed the significant interaction
effects between time and intervention for adiponectin (Wald
Chi- square test= 16.2, P < .001), leptin (Wald Chi- square
test= 9.4, P = .002), and chemerin (Wald Chi- square test=
11.6, P = .001) (Figure 4A,B and D). The main effect of
yoga intervention was found for PAI- 1 (Wald Chi- square
test= 5.9, P = .015) (Figure 4C). However, the main effect of
time was observed for visfatin (Wald Chi- square test= 11.78,
P = .001) (Figure 4E).
4
|
DISCUSSION
MetS is a serious public health concern due to its intimate
link to the pathogenesis of diabetes mellitus, stroke, and
cardiovascular diseases. In 2010- 2012, the prevalence rate
1134
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SUPRIYA etAl.
of MetS in Hong Kong was ~27% according to the NCEP
ATP III criteria.7 Central obesity and insulin resistance
have been proposed as the prominent underlying contribu-
tors to MetS. Remarkably, as high as 85% of MetS individ-
uals have been shown to have elevated blood pressure or
hypertension.3 Individuals with both MetS and hyperten-
sion are indeed considered to be significantly challenged
and at risk for additional morbidities.18 Adipocytes syn-
thesize and release adipokines such as adiponectin, leptin,
angiotensin, perivascular relaxation factors, and resistin,
which are all linked with blood pressure control. As adi-
pokines are considered regulators of MetS, the equilibrium
and balance of adipokines become an important topic to be
explored in studies of obesity, hypertension, and MetS. Our
present findings reveal that 1- year yoga training increases a
circulatory anti- inflammatory adipokine (adiponectin) and
decreases proinflammatory adipokines (leptin, chemerin,
and PAI- 1) in MetS participants with high- normal blood
pressure. These novel results support the beneficial com-
plementary role of yoga exercise in the management of
MetS by illustrating the favorable modulating effects of
yoga training on blood adipokines.
Reduction in waist circumference and blood pressure
has been shown to be positive health consequences of reg-
ular yoga training.7,19 Waist circumference and visceral fat
were decreased after 16 weeks of yoga training compared
to a control group of healthy post- menopausal women aged
54.5 ± 2.8 years.19 Overweight/obese women and breast
cancer survivors have also been shown to reduce waist cir-
cumference after receiving 6 months of yoga training when
compared to breast cancer survivors who did not receive yoga
intervention.20 Another study demonstrated that blood pres-
sure was significantly reduced by yoga exercise intervention
in patients with mild hypertension.21 Consistently, our previ-
ous investigation also demonstrated that 1- year yoga training
decreased waist circumference and tended to reduce systolic
blood pressure in middle- aged and older adults with MetS
compared to the control group who did not receive yoga in-
tervention.7 Our results are in accordance with the previous
findings that the average waist circumference was signifi-
cantly decreased; however, both systolic and diastolic blood
pressures were not decreased in participants with yoga inter-
vention compared to the control participants with MetS and
high- normal blood pressure. This study further explored the
effect of yoga on the specific subject group with MetS and
Control group
(n = 45)
Yoga group
(n = 52) P- value
Gender 17 M, 28 F 17 M, 35 F .60
Age (yrs) 56.5 ± 8.6 58.5 ± 9.5 .26
Diastolic blood pressure (mm Hg) 85.8 ± 8.8 84.5 ± 7.8 .35
Systolic blood pressure (mm Hg) 141.7 ± 13.8 140.3 ± 13.5 .35
Waist circumference (cm) 89.8 ± 7.1 90.4 ± 9.2 .78
Fasting glucose (mmol/L) 5.56 ± 0.9 5.58 ± 0.5 .23
Blood triglycerides (mmol/L) 2.1 ± 1.0 1.9 ± 0.9 .33
Blood high density lipoprotein- C
(mmol/L)
1.3 ± 0.3 1.2 ± 0.3 .52
IPAQ activity (min/week) 3888.78 ± 4204.1 2593.66 ± 2232.3 .16
IPAQ sitting (min/wk) 2532.78 ± 1774.1 2306.75 ± 1500.3 .99
Adiponectin (ng/mL) 6484 ± 1803 6409 ± 1753 .88
Plasminogen activator inhibitor- 1
(ng/mL)
6.4 ± 2.6 6.0 ± 2.6 .28
Visfatin (ng/mL) 3.5 ± 2.9 3.5 ± 2.0 .18
Chemerin (ng/mL) 221.4 ± 70.7 230.1 ± 90.4 .60
Leptin (ng/mL) 22.2 ± 9.8 25.4 ± 11.5 .18
TABLE 2 Baseline characteristics of
metabolic syndrome risk factors, IPAQ
activity and sitting, and adipokines in
control and yoga groups
FIGURE 1 Change in waist circumference in control and yoga
groups. The box plot represents the change (ie, post- pre) in waist
circumference after yoga training in subjects with MetS and high-
normal blood pressure. Statistical significance was set at P < .05
|
1135
SUPRIYA etAl.
high- normal blood pressure by investigating the interaction
effect between yoga and the 1- year time period. Our results
indicated that there was no interaction effect between yoga
and the 1- year time period for any of the five risk factors of
MetS in our examined participants with high- normal blood
pressure. In accordance with our previous study assumptions
that the effects of yoga exercise on systolic blood pressure
might be dependent on the quantity of the intervention and/or
subject compliance to the intervention,7 we again suggested
that extra attention should be given to MetS participants
with high- normal blood pressure. The controversial results
might be explained by the complexities involved in defining
MetS. An equal number of MetS risk factors might not in-
dicate that the participants shared the same characteristics
and cardiometabolic risk factor profile. Indeed, the specific
outcomes/consequences of MetS are difficult to evaluate
without a solid definition and common criteria for diagnosis.
Nonetheless, our results support the notion that “MetS in hy-
pertension is an unholy alliance.”18
Evidence indicates that biomarkers might be valuable in
diagnosing and estimating the disease risk for a population
and managing many pathological states, especially when
clinical signs or obvious anatomic abnormalities are absent
or not evident.22 For example, insulin resistance is one of the
major risk factors of type 2 diabetes (T2D). Markers for indi-
cating insulin resistance might be useful for prevention of car-
diovascular disease, all- cause mortality, and T2D. Increased
concentrations of interleukin- 8 (IL- 8), monocyte chemotactic
protein- 1 (MCP- 1), and interferon γ- induced protein (IP- 10)
have been associated with the incidence of T2D by hazard
ratio risk assessment. One study suggested that chemokines
including MCP- 1, IL- 8, and IP- 10 were significantly higher
in participants who developed T2D during a follow- up of
10 years compared with those who did not develop T2D.23
An aerobic exercise (225 min/wk) intervention conducted on
post- menopausal inactive women resulted in decreases in in-
sulin resistance markers (leptin, adiponectin/leptin ratio, in-
sulin), whereas changes in glucose (one of the risk factors for
MetS) were not evident.24 Another study by the same group
suggested that adipokines and systemic inflammation may be
associated with the risk of breast cancer in post- menopausal
women independent of body mass index.25 They concluded
that after performing long- term aerobic exercise, previously
inactive post- menopausal women showed changes in insulin,
leptin, and adiponectin/leptin, which might reduce the risk
of post- menopausal breast cancer.24 Numerous studies sup-
port the idea that hypertensive patients with MetS will show
early signs of end- organ damage, which are recognized as
significant independent predictors of adverse cardiovascular
outcomes compared to those without MetS.26 Therefore, in-
dividuals with high- normal blood pressure and MetS should
receive special attention.
Researchers suggested that MetS identification should be
emphasized when treating patients with hypertension.27,28 In
this study, adipokines were observed to be favorably regulated
after yoga intervention in MetS subjects with high- normal
blood pressure. These results proposed that an adipokine
panel as a circulatory biomarker might be useful for identi-
fying the protective outcomes of interventions, especially in
worsening metabolic conditions in which changes in clinical
outcomes are not obvious. Biomarkers aid in the diagnosis
and management of many pathological states when there
FIGURE 2 Cardiometabolic risk
factors in control and yoga groups. Line
graphs represent the changes in systolic
blood pressure (A), diastolic blood pressure
(B), high- density lipoprotein cholesterol (C),
triglycerides (D), fasting glucose (E), and
waist circumference (F) before (Pre) and
after (Post) the 1- year experimental period
in MetS subjects with high- normal blood
pressure in control (n = 45) and yoga groups
(n = 52). Statistical significance was set at
P < .05. Data are expressed as the means ±
standard deviation
1136
|
SUPRIYA etAl.
are no obvious clinical signs or anatomic abnormalities.13
Nonetheless, each adipokine has a particular role in maintain-
ing the delicate equilibrium between the pathophysiological
effect and protective impact. Although numerous effects of
adipocytokines have been reported in recent studies, further
investigation of their signalling pathways is still needed to
understand how they are eventually integrated.
The regular practice of yoga exercise has been demon-
strated to be effective in reducing stress and improving
physical and psychologic health. Yoga exercise has also
been proposed to reduce oxidative stress by at least two
mechanisms.29,30 The first mechanism is via the suppres-
sion of the overactivated sympathoadrenal system and the
hypothalamic- pituitary- adrenal (HPA) axis,29,30 which re-
duces the proinflammatory responses by decreasing the lev-
els of stress hormones such as cortisol and epinephrine.29,30
Yoga exercise has been shown to alleviate inflammatory
signalling by downregulating the regulatory molecule that
favors the proinflammatory microenvironment,31 namely,
the nuclear factor kappa- light- chain- enhancer of activated
B cells (NF- κB).32 Consistent with the role of NF- κB, the
downregulation of the regulatory molecules for the proin-
flammatory microenvironment reasonably explains the
principal behind the first mechanism. The second mecha-
nism is attributed to the reactivation of the parasympathetic
nervous system by consciously manipulating the breath
rhythm (ie, slow breathing and a long exhalation) during
yoga practice.25 The activities of adenosine monophosphate-
activated protein kinase (AMPK) in peripheral tissues and
organs are known to be facilitated by the specific regulation
of the sympathetic and parasympathetic nervous systems.33
Intriguingly, AMPK is a regulatory molecule that favors
FIGURE 3 Changes in adipokines in
control and yoga groups. Box plots represent
the changes (ie, post- pre) in adipokines
including adiponectin (A), plasminogen
activator inhibitor- 1 (B), chemerin (C), and
leptin (D) after yoga training in subjects
with MetS and high- normal blood pressure.
Statistical significance was set at P < .05
FIGURE 4 Adipokines in control
and yoga groups. Line graphs represent the
concentrations of leptin (A), plasminogen
activator inhibitor- 1 (B), chemerin
(C), visfatin (D), and adiponectin (E)
before (Pre) and after (Post) the 1- year
experimental period in MetS subjects with
high- normal blood pressure in control
(n = 45) and yoga groups (n = 52).
Statistical significance was set at P < .05.
Data are expressed as the means ± standard
deviation
|
1137
SUPRIYA etAl.
the anti- inflammatory microenvironment. AMPK functions
to mediate fat oxidation, reduce circulating fatty acids and
triacylglycerol, and increase glucose transport in muscle.
In mammals, AMPK has been demonstrated to contribute
to glucose homeostasis, appetite regulation, and exercise
adaptation.34 Thus, the upregulation of anti- inflammatory
responses by increasing fat oxidation, reducing circulatory
fatty acids, and promoting insulin sensitivity through the
AMPK pathway sensibly contributes to the principal behind
the second mechanism. Nevertheless, the precise underly-
ing mechanisms that explain how yoga practice causes the
observed alterations of circulatory adipokines are unclear,
and this topic warrants additional research to fully under-
stand the relationship between yoga exercise training and the
adipokine profile. Provided that MetS is a condition that is
characterized by chronic low- grade inf lammation, it is ratio-
nal that an equilibrium between the anti- inflammatory and
proinflammatory microenvironments plays a critical role in
preventing the development of MetS.
We aimed to provide an estimate of the true efficacy of the
intervention, that is, among those who completed the treat-
ment as planned (per protocol analysis). Nonetheless, the
convenience sampling with restricted inclusion criteria and
the use of per protocol analysis in our study design might
have limited the study generalizability and exaggerated the
treatment effect. Future research with the inclusion of both
intention to treat analysis and per protocol analysis in the
study design might be able to strengthen the present findings.
Furthermore, the inclusion of active control group might fur-
ther enhance the significance of the findings. It remains to be
elucidated whether the establishment of a regular gathering
group and regular exercise habit might contribute to the ben-
eficial effects of our observed outcome measures other than
the yoga intervention.
5
|
PERSPECTIVE
This study demonstrates that 1- year yoga training induces a
favorable modulation of circulatory adipokines. These find-
ings support the notion that yoga exercise might serve as an
effective lifestyle intervention to reduce chronic inflamma-
tion by downregulating the proinflammatory adipokines and
upregulating the anti- inflammatory adipokines in individuals
with high- normal blood pressure and MetS. A panel of adi-
pokines as circulatory biomarkers might be useful for moni-
toring the beneficial outcomes of prolonged yoga exercise
interventions.
ACKNOWLEDGEMENTS
This study was supported by the Hong Kong Research Grants
Council Hong Kong Ph.D. Fellowship Scheme (RTVX
PF13- 11753), The Hong Kong Polytechnic University
Research Fund (1- ZE17), and The University of Hong Kong
Seed Fund for Basic Research.
CONFLICT OF INTEREST
All authors declare no conflict of interest.
AUTHOR CONTRIBUTIONS
R.S. contributed to design, conduct/data collection, analysis
of the paper, and writing of the paper. A.P.Y. contributed
to data collection. P.H.L. contributed to statistical analyses.
C.W.L., L.W.C., and B.Y.Y. contributed to design and analy-
sis of the paper. K.K.C. and S.Y.Y. contributed to analysis of
the paper. P.M.S. contributed to the design, analysis of the
paper, and writing of the paper.
ORCID
Paul H. Lee http://orcid.org/0000-0002-5729-6450
Parco M. Siu http://orcid.org/0000-0002-3548-5058
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How to cite this article: Supriya R, Yu AP, Lee PH,
etal. Yoga training modulates adipokines in adults
with high- normal blood pressure and metabolic
syndrome. Scand J Med Sci Sports. 2018;28:1130–
1138. https://doi.org/10.1111/sms.13029
