A preview of this full-text is provided by SAGE Publications Inc.
Content available from Journal of Evidence-Based Complementary & Alternative Medicine
This content is subject to copyright.
Topical Review
Oxygen Consumption Changes With Yoga
Practices: A Systematic Review
Anupama Tyagi, MA
1
and Marc Cohen, PhD, MBBS (Hons)
1
Abstract
Oxygen consumption varies with physical and mental activity as well as pathological conditions. Although there is a strong
relationship between yoga and metabolic parameters, the relationship between yoga and oxygen consumption has not yet been
formally reviewed. This systematic review attempted to include all studies of yoga that also measured oxygen consumption or
metabolic rate as an outcome. A total of 58 studies were located involving between 1 and 104 subjects (average 21). The studies
were generally of poor methodological quality and demonstrated great heterogeneity with different experimental designs, yoga
practices, time periods, and small sample sizes. Studies report yoga practices to have profound metabolic effects producing both
increase and decrease in oxygen consumption, ranging from 383%increase with cobra pose to 40%decrease with meditation.
Compared to nonpractitioners, basal oxygen consumption is reported to be up to 15%less in regular yoga practitioners, and
regular yoga practice is reported to have a training effect with oxygen consumption during submaximal exercise decreasing by
36%after 3 months. Yoga breathing practices emphasize breathing patterns and retention ratios as well as unilateral nostril
breathing, and these factors appear critical in influencing oxygen consumption. A number of studies report extraordinary voli-
tional control over metabolism in advanced yoga practitioners who appear to be able to survive extended periods in airtight pits
and to exceed the limits of normal human endurance. More rigorous research with standardized practices is required to
determine the mechanisms of yoga’s metabolic effects and the relevance of yoga practices in different clinical populations.
Keywords
yogic, meditation, pranayama, metabolic rate/cost, oxygen consumption, energy expenditure
Received February 25, 2013. Received revised April 25, 2013. Accepted for publication April 29, 2013.
Introduction
Human metabolism is the result of continuous anabolic and
catabolic processes that maintain homeostasis and sustain life.
Metabolic pathways include a complex network of nutritional,
neuronal, and humoral inputs that are integrated by the central
and autonomic nervous systems through pathways that monitor
and maintain physiological functioning. All metabolic pro-
cesses generate heat and are ultimately dependent on the
expenditure of energy via consumption of oxygen, which
drives oxidative phosphorylation.
Energy expenditure is a directly related to metabolic rate and
oxygen consumption, and these terms are often used interchange-
ably. Monitoring oxygen consumption has received a great deal
of interest in determining oxygen delivery to tissues, cardiore-
spiratory function, and metabolic response to activity. Assess-
ment of oxygen consumption is used in determining energy
requirements for healthy lifestyles, exercise programs, and criti-
cally ill patients.
1-3
Oxygen consumption is reported to increase
with adaption to physiological stress and pathology.
4,5
The mea-
surement of energy expenditure can be performed via direct
calorimetry, which measures heat loss using insulated chambers,
or via indirect calorimetry, which directly measures oxygen
consumption
6
through respiratory gas exchange. Direct calori-
metry is not frequently used as it is complex, does not accurately
measure rapid changes in metabolism, and requires significant
expertise and elaborate equipment including specially con-
structed chambers. Indirect calorimetry is the most commonly
used technique for measuring energy expenditure and can be
used to measure the substrate of metabolism as well as oxygen
consumption, which can be expressed in terms of VO
2
(absolute
oxygen consumption), VO
2
/kg/min (relative oxygen consump-
tion), and MET (metabolic equivalent task).
2,3,7
Oxygen Consumption, Stress, and Pathology
Oxygen consumption is maximal during intense physical activ-
ity and lowest during basal or resting conditions and higher
1
RMIT University, Bundoora, Victoria, Australia
Corresponding Author:
Marc Cohen, PhD, MBBS(Hons), School of Health Sciences, RMIT University,
PO Box 71, Bundoora, Victoria 3083, Australia.
Email: marc.cohen@rmit.edu.au
Journal of Evidence-Based
Complementary & Alternative Medicine
18(4) 290-308
ªThe Author(s) 2013
Reprints and permission:
sagepub.com/journalsPermissions.nav
DOI: 10.1177/2156587213492770
cam.sagepub.com
oxygen consumption is associated with psychological and phy-
siological activity, stress, pathology, and accelerated aging.
4,5,8,9
Oxygen consumption has also been found to increase with activ-
ities such as mental arithmetic and playing video games,
10-13
as
well as with psychological distress and anxiety.
14
Agrowing
body of research further suggests that oxygen consumption is
higher in various pathological conditions, including congestive
heart failure,
15
locomotor impairment,
16
HIV,
17
chronic obstruc-
tive pulmonary disease,
18
insomnia,
2
and congestive heart fail-
ure.
19
Oxygen consumption has also been found to increase
with features of metabolic syndrome,including obesity,
20-22
type
2diabetes,
23-26
and hypertension.
27-29
The measurement of oxygen consumption can provide
insights into overall homeostatic balance and response to stress,
which are mediated through multiple pathways under the
control of the autonomic nervous system and the hypothala-
mus. The sympathetic nervous system is involved in rapidly
mobilizing vital physiological functions via sympathetic–adre-
nal–medullary pathways in response to acute stress,
30-32
which
serves to increase oxygen consumption. Repeated or chronic
stressful stimuli may lead to changes in the hypothalamic–adre-
nal–pituitary axis, leading to a sustained stress response involving
cognitive, emotional, endocrine, and immune system changes.
33
The parasympathetic nervous system provides a counter to the
stress response and reduces oxygen consumption byactivating the
so-called relaxation response,
34
which serves to reduce physiolo-
gical arousal and induce a hypometabolic state mediated via
enhanced vagal activity.
35
Such hypometabolic states are sug-
gested to enhance survival in plants and animals by facilitating
restorative and repair functions.
36
Yoga, Stress, and Metabolism
Mind–body practices that induce relaxation have been tradi-
tionally used by people across cultures to improve health and
serve as a path for spiritual awakening.
37
Yoga is an ancient
mind–body approach that combines the practice of postures
(asana), breathing (pranayama), and meditation (dhyana) with
the aim of achieving an effortless state of harmony (samadhi).
Yoga postures include both static and dynamic postures that
are designed to attune the body to a stable state suitable for
meditation. Yoga breathing includes a range of practices such
as Bhastrika (bellows breath), Ujjayi (victorious breath),
Kapalbhati (lustrous cranium), and unilateral nostril breathing,
which can be performed at different rates (reported as breath/
minute) and with different retention periods and patterns that
involve either internal retention (inspiration–retention–expira-
tion) or external retention (expiration–retention–inspiration).
The yogic state of meditation is characterized by decreased
oxygen consumption and cardiovascular activity
35,38
and has
been shown to elicit the relaxation response.
34
This meditative
state, which is distinct from rest,
39,40
physical relaxation,
41
and
sleep,
42
may be voluntarily induced, even while performing
fixed physiological workloads.
43
The ability of yoga to induce relaxation and relieve stress has
been widely reported,
44-46
and there are reports of yoga practices
reducing acute, chronic, and posttraumatic stress. For example,
yoga is reported to relieve workplace stress,
47
examination
stress,
48,49
and stress-induced inflammation.
50
Yoga practices
have also been reported to improve many clinical conditions
such as anxiety,
51-53
depression,
53,54
negative mood states,
55-58
and posttraumatic stress disorder (PTSD) symptoms in war
veteran,
59-61
tsunami survivors,
62,63
hurricane refugees,
64
and
flood survivors.
65
Furthermore, 2 reviews, one involving 35 clin-
ical studies
66
and the other 8 controlled trials of healthy adults,
67
acknowledge the promising role of yoga in reducing stress. Li
et al also suggest yoga as a potential adjunct to pharmacologic
therapy for patients with stress and anxiety.
66
There are further
studies to suggest that regular yoga practice reduces physiologi-
cal and metabolic activity under normal conditions. Compared to
nonpractitioners, regular yoga practitioners have been found to
have lowered resting heart rate,
68
blood pressure,
68
breath rate,
69
and metabolic rate.
70,71
Yoga has also been found to improve all
features of metabolic syndrome, including obesity,
72,73
hyperli-
pidaemia,
74-76
hyperglycemia,
75,77,78
and hypertension,
79-81
with
3 separate randomized controlled trials demonstrating benefits of
yoga in metabolic syndrome patients.
82-84
While there seems to be a strong relationship between yoga
and metabolic parameters, the relationship between yoga and
oxygen consumption has not been formally reviewed. The
objective of this article is to systematically review previous
research exploring the relationship between yoga and oxygen
consumption and explore the impact that different yoga prac-
tices has on oxygen consumption in different populations.
Methodology
For this systematic review, a comprehensive search of multiple data-
bases including Scopus, PUBMED, PSYCHINFO, CINAHL, Science
Direct database was conducted, and a separate search was conducted
in Indian medical journals through IndMed, which indexes more than
100 prominent Indian scientific journals. Similarly, a search was
performed of Yoga Mimamsa, which includes published yoga research
literature dating back from 1920 not listed in the above databases. The
archives of the International Journal of Yoga were also searched,
along with the reference citations from all full-text articles identified.
The primary search terms included Yoga, yogic, pranayama, yoga
nidra, breathing, relaxation, meditation, Transcendental meditation,
Brahamakumari meditation, Raja Yoga meditation, Om meditation,
mantra meditation, Sahaj Yoga meditation, cyclic meditation, and
Kundalini yoga, Kriya yoga, and Sudarshan Kriya along with key-
words oxygen consumption,energy expenditure,metabolic cost, and
metabolic rate.
All studies that had oxygen consumption (at resting, during yoga
intervention, or during physical exercise in which yoga included in
the intervention) as an outcome were included in the systematic
review. The search was performed for articles published up to Decem-
ber 2012 and was not otherwise restricted by date or study population.
The review included studies that examined a range of yoga practices
including asana and/or integrative yoga, breathing, meditation and
yogic relaxation practices used either alone or as an integrated practice.
The studies were excluded if they were not in English (n ¼4),
unobtainable (n ¼5), in press (n ¼8), or only documented study
protocol (n ¼5). Studies were also excluded if they only involved
Tyagi and Cohen 291
meditation (religious or nonreligious) and relaxation practices that are
not directly associated with yoga such as Zazen/Zen Buddhist medita-
tion, Vipassana Meditation, Tum-Mo yoga, Qigong,relaxation
response, progressive muscle relaxation, and autogenic relaxation.
However, it was beyond the scope of this systematic review to collect
and synthesize clinical outcomes other than oxygen consumption or cri-
tically assess the methodological quality of all studies. The selection of
relevant studies is shown in Figure 1, and the results, including their
statistical significance, are noted in the relevant text and tables.
Results
A total of 58 studies of oxygen consumption and yoga prac-
tices were extracted (Figure 1). These studies involved
between 1 and 104 subjects (average 21) and demonstrated
great heterogeneity with many different experimental designs,
yoga practices, and time periods. Extracted studies, which
were categorized according to the type of intervention (pra-
nayama practice, meditation/relaxation, integrated yoga/
asana practice, integrated yoga with physical activity), are
presented in Tables 1 to 4, which also include information
about study design.
Of the total studies, 35 studies were published from
India,
70,71,85-117
15 from the United States,
118-132
2 from the
United Kingdom,
133,134
and 1 each from Mexico,
135
New Zeal-
and,
136
Thailand,
137
Brazil,
138
Japan,
139
and Sweden.
140
Most
studies reported assessing direct measurement of respired gases
for measuring oxygen consumption using indirect calorimetry
techniques, whether through open circuit, closed circuit, bag
system, or respiratory chamber method. Some studies derived
oxygen consumption through the standard equations, that is,
oxygen consumption was predicted through regression
equation with measures of heart rate and oxygen consumption
of submaximal exercise,
94
while VO
2
max was predicted
through achieved workload and using standard formula from
the American College of Sports and Medicine.
116,130
Oxygen
consumption was reported to both increase and decrease with
different yoga practices. Increases in oxygen consumption ran-
ged from 7.7%with Ujjayi breathing to 383%during cobra
pose (Tables 1 and 3). Studies also report decreases in oxygen
consumption, with slow yoga breathing techniques and medita-
tion practices ranging from a 3.7%decrease during Om medi-
tation to a 40%decrease in an advanced yogi during meditation
in an airtight pit (Table 2). Basal oxygen consumption is also
Studies identified
in primary search
(n=254)
Studies identified
through other
sources (n=29)
Total studies
(n= 283)
Relevant Studies
remaining (n=151)
Non English Literature (n=4)
Unobtainable (n=12)
In press (n=7)
Protocol (n=5)
Filtered studies
extracted (n=123)
Review –8
Letters-3
Reports and overview -5
OC not an outcome -38
Intervention other than yoga -11
Identification
Screening
Eligibility
Included
Duplicate
articles (n= 132)
Finally selected studies (n=58) with 2 studies included in more than
one category (Ray, Pathak et al. 2011 & Danucalov, SimÃμes et al. 2008)
Pranayama (n=16)
Meditation/Relaxation (n= 15)
Asana and integrated yoga (n=13)
Integrated Yoga with physical activity (n=17)
●
●
●
●
Figure 1. Flow chart of study search and included studies.
292 Journal of Evidence-Based Complementary & Alternative Medicine 18(4)
Table 1. Summary of Studies Reporting Changes in Oxygen Consumption With Pranayama Practice(s).
Study Reference Population Study Design Intervention Comparators Metabolic Measures
Cardiorespiratory and Other
Measures
Miyamura et al
(2002)
139
Advanced male yoga
practitioner (n ¼1)
Single practice on a
single occasion
Ujjayi breathing at 1 breath/min Pranayama versus post-
pranayama
"of 10%in OC during Ujjayi HR during breathing session 9%
higher compared to post
Miles and Behanan
(1934)
118
Male yoga practitioner
(n ¼1)
Multiple practices on a
single occasion
Ujjayi,Kapalbhati, and Bhastrika
breathing
Sitting and reclined
postures versus
Pranayama
"of 33%,35%, and 30%in OC of
during pranayama compared to
sitting and 39%,41%, and 36%
compared to reclined
Miles (1964)
119
Male yoga practitioner
(n ¼1)
Multiple practices on
multiple occasions
Ujjayi (40 seconds retention at 1.26
breath/min); Kapalbhati (12.5 and
80 breath/min); Bhastrika (21 and
1.3 breath/min)
Baseline versus
pranayama practices
"of 25%in OC during Ujjayi,12%
during Kapabhati, and 19%during
Bhastrika
Rao (1968)
86
Male yoga practitioner
(n ¼1)
Single practice on 2
occasions
Ujjayi breathing at 2 different altitudes
of 520 m and 3800 m
Baseline versus Ujjayi
breathing at low
altitude; Baseline
breathing versus Ujjayi
at high altitude
"of 7.7%in OC during Ujjayi with
breath rate 1.5 breath/min at low
altitude
"of 9.9%in OC during Ujjayi at
breath rate 3 breath/min at high
altitude
OC during Ujjayi at high altitude was
16%higher compared to lower
altitude
Karambelkar et al
(1982)
87
Male yoga practitioners
(n ¼8)
Multiple practices on a
single occasion
Kapalbhati at 120 breath/min and
hyperventilation breathing at 26
breath/min
Baseline breathing versus
Kapalbhati breathing
and hyperventilative
breathing
"of 50%in OC and "of 33%in CO
2
exhalation during Kapalbhati
"of 209%in MV and #of 63%in
VT during Kapalbhati
"of 133%in OC and "of 379%in
CO
2
exhalation during
hyperventilative breathing
"of 538%in MV and "of 250%in
VT during hyperventilative
breathing
Karambelkar et al
(1982)
88
Male yoga practitioners
(n ¼3)
Multiple practices on a
single occasion
Bhastrika with internal retention
(I:R:E ¼8:32:16) and external
retention (E:R:I ¼3:20:10)
Baseline versus Bhastrika
breathing with internal
retention and external
retention
Internal Retention: "of 15%in OC
and "of 13%in CO
2
exhalation
during Bhastrika
External retention: "of 17%in OC
and "of 32%in CO
2
exhalation
during Bhastrika
Frostell et al
(1983)
140
Experienced male yoga
practitioners (n ¼3)
Single practice on a
single occasion
Bhastrika at 232 breath/min Baseline versus
pranayama
"of 208%in OC and "of 395%in
CO
2
exhalation during Bhastrika
"of 30 BPM (47%)inHR
"of 88.4 L/min (15-fold increase)
in MV
"of 65%in CO
Karambelkar and
Bhole (1988)
89
Male yoga practitioners
(n ¼7)
Single practice on a
single occasion
Kapalbhati at 120 breath/min Pranayama practices
versus baseline
"of 51%in OC and "of 34%in CO
2
exhalation during Kapalbhati
"of 219%in MV during breathing
Karambelkar et al
(1983)
90
Male yoga practitioners
(n ¼3)
Multiple practices on a
single occasion
Bhastrika with external retention
(E:R:I ¼3:20:10) and Ujjayi with
external retention (E:R:I ¼
6:12:12)
Pranayama practices
versus baseline
"of 24%in OC and "of 32%in CO
2
exhalation during Bhastrika
#of 4%in OC and #of 7%in CO
2
exhalation during Ujjayi
(continued)
293
Table 1. (continued)
Study Reference Population Study Design Intervention Comparators Metabolic Measures
Cardiorespiratory and Other
Measures
Karambelkar et al
(1983)
91
Regular and beginner male
yoga practitioners
(n ¼9)
Single practice on a
single occasion
Ujjayi breathing with internal (I:R:E ¼
8:32:16)
Pranayama versus baseline Significant #of 21%in OC and "of
34%in OC was observed during
the same practices, #OC was only
seen in the regular yoga
practitioners
Danucalov et al
(2008)
138
Experienced yoga
practitioners with >3
years of experience
(n ¼9)
Multiple practices on a
single occasion
Slow paced pranayama with extended
period of retention (internal
retention; I:R:E ¼1:4:2) and
meditation; each phase of 30
minutes
Pranayama versus
meditation and
baseline
"of 20%in OC and "of 25%in CO
2
exhalation during pranayama
compared to baseline
#of 35%in OC during meditation
compared to baseline
"of 84.6%in OC during pranayama
compared to meditation
Telles and
Desiraju
(1991)
92
Male yoga practitioners;
short breath retention
group (n ¼5) and long
breath retention group
(n ¼10)
Multiple practices on a
single occasion
Ujjayi breathing with 2 different
internal retention periods: short
retention (I:R:E ¼1:4:4) and long
retention (I:R:E ¼1:1:1)
Baseline versus Pranayama "of 52%in OC (P< .05) during
pranayama with short retention
(1:1:1); #of 19%in OC (P<.025)
during pranayama with long
retention (1:4:4)
Telles et al
(1996)
93
Male yoga practitioners
(n ¼12)
Multiple practices on
2 occasions
RNB session and normal breathing
session (each session of 45
minutes on different days)
Baseline breathing versus
post-RNB session and
post-RNB session
"of 18%in OC (P< .05) after RNB;
no significant change after normal
breathing compared to baseline
"of 9.3%SBP (P< .05) after RNB
#of 60%in GSR after RNB
Prasad et al
(2001)
94
Male yoga practitioners
with >3 years’
experience (n ¼12)
Multiple practices on a
single occasion
ANB for 30 minutes, treadmill walk at
3 km/h (1.9 mph) for 30 minutes,
and field walk 1.5 km/30 min
Resting, field walk, and
treadmill walk versus
ANB
"of 150%in OC (P< .01) during ANB
compared to resting state OC
during ANB 19.6%(P< .05) lower
compared to field walk and 37.5%
(P< .01) lower compared to
treadmill walk
Ray et al (2011)
95
Male yoga practitioners
with >6 years’
experience (n ¼20)
Multiple practices on
2 occasions
Hatha yoga session comprising
variety of yoga static postures
interspersed with Shavasana,
pranayamas, and meditation
practices; VO
2max
session (each
session on different days)
Sitting rest (Sukhasana)
versus each individual
pranayama versus rest
sitting
#of 16%in OC during Bhastrika;"of
65%,61%,33%(Ps < .05) in OC
during Raven beak (Kaki Mudra)
breathing (P< .05), 61%during I
breathing (P< .05), 103 mL/min
(33%) during Kapalbhati (P< .05)
Telles et al
(1994)
96
Male yoga practitioners
(n ¼48)
Four weeks regular
practice in multiple
groups
Random assignment to RNB (n ¼12),
LNB (n ¼12), or ANB (n ¼24);
each assigned breathing 4 times
daily for 4 weeks
Post-pranayama
intervention for versus
preintervention
"of 37%in OC (P< .05) post-RNB, "
of 24%in OC post-LNB, and "of
18%in OC post-ANB compared
to preintervention
#in body weight after 1 month of
pranayama
"of 9.6%and 7%in HR (Ps<
.001) post-RNB and post-ANB
respectively
"of 150%in GSR (P< .05) post-
LNB
Abbreviations: OC, oxygen consumption; HR, heart rate; CO
2
, carbon dioxide; MV, minute ventilation; VT, tidal volume; I:R:E, inspiration–retention–expiration; E:R:I, expiration–retention–inspiration; BPM, beats per
minute; CO, cardiac output; RNB, right nostril breathing; SBP, systolic blood pressure; GSR, galvanic skin resistance; ANB, alternate nostril breathing; LNB, left nostril breathing.
294
Table 2. Summary of Studies Reporting Changes in Oxygen Consumption With Mediation/Relaxation Practice(s).
Study Reference Population Study Design Intervention Comparators Metabolic Measures
Cardiorespiratory and Other
Measures
Anand et al (1961)
97
Experienced male yoga
practitioner (n ¼1)
Single practice on 2
occasions
Stay in airtight box during 2
different days of 10 hours
each
Baseline (basal) versus stay in
box
#of 37.4%and 32%in OC during 2
different sessions
#in HR up to 25 BPM during
session; HR rose only when
ambient O
2
declined to 15%
and CO
2
reached to 5%in the
pit; OC declined to 50%of
BMR (19.5 L/h) on one
occasion
Karambelkar et al
(1968)
98
Experienced male yoga
practitioners (n ¼4)
Single practice on a
single occasion
Stay in airtight pit >12 hours
and up to 18 hours
Baseline (basal) versus stay in
pit
OC during stay in pit lesser than basal
condition; subjects remained in pit
till ambient O
2
declined to 12%
and CO
2
rose to 7%; The
maximum stay in pit for 18 hours
when ambient CO
2
was 7.7%and
O
2
11.6%
HR and BR rose when ambient
CO
2
reached to 5%in pit
Craig Heller et al
(1987)
99
Yogi male (proficient in
bhoogarbh smadhi
(subterranean stay) (n ¼1)
Single practice on a
single occasion
Stay in subterranean chamber
for 4 hours
Baseline (basal) versus stay in
pit
#of 40%in OC during the stay in
chamber compared to basal
baseline measured through gas
volume meter
Wallace (1970)
120
Meditators with >6 months
experience (n ¼15)
Single practice on a
single occasion
Transcendental meditation
(TM); 30 minutes
meditation session
Baseline versus meditation #of 20%in OC during meditation
compared to baseline
"of 103%in GSR during onset of
meditation
Wallace et al
(1971)
121
Meditators with mean 29.4
months experience
(n ¼36)
Single practice on a
single occasion
Transcendental meditation;
30 minutes meditation
session
Baseline versus meditation #of 17%in OC (P< .005) and #of
15%in CO
2
exhalation (P< .005)
during meditation
#in HR and BR (Ps < .05) during
meditation; "of 158%in GSR
(P< .005) during meditation
Benson et al (1975)
122
Meditators with >1 year
experience (n ¼13)
Single practice on a
single occasion
Transcendental meditation;
30 minutes meditation
session
Baseline versus meditation #of 5%in OC (P< .001) and #of 6%
in CO
2
exhalation (P< .001)
during meditation
#in HR (P< .01) during
meditation
Danucalov et al
(2008)
138
Experienced yoga
practitioner with >3 years’
experience (n ¼9)
Multiple practices on a
single occasion
Slow paced Pranayama with
extended period of
retention (internal
retention—I:R:E ¼1:4:2)
and meditation; Each phase
of 30 minutes
Baseline versus meditation
and pranayama
#of 35%in OC (P< .05) and #31.2%
in CO
2
exhalation (P< .05) during
meditation compared to baseline;
#of 49%in OC during meditation
compared to pranayama
#of 8%in HR (P< .05) during
meditation compared to
baseline and pranayama;"of
20%in OC during pranayama
compared to baseline
Fenwick et al
(1977)
134
Meditators with >22 months
experience (n ¼11) and
nonmeditators (n ¼8)
Multiple practices on a
single occasion
Transcendental meditation
(TM) and listening music
Baseline versus meditation
and listening to music in
meditators and
nonmeditators;
comparison between
groups
Nonsignificant drop in OC and CO
2
exhalation during meditation in
meditators and nonmeditators;
nonsignificant difference in
reduction of OC between
meditation and listening music;
nonsignificant difference between
groups
No evidence of hypometabolism
during meditation in both the
groups
Warrenburg et al
(1980)
123
Regular meditators with mean
3.4 years’ experience (n ¼
9); regular relaxation
practitioners with mean 6.4
years’ experience (n ¼9);
nonpractitioners (n ¼9)
Multiple practices on a
single occasion
Transcendental meditation
(TM); progressive muscle
relaxation (PMR);
nonpractitioner—listening
music
Control periods of closed
eyes and reading book
versus intervention;
comparison between
groups
#in OC during TM 4%, during PMR
3.5%, in regular practitioners, and
8.3%in nonpractitioners (Ps < .01)
compared to periods of control;
nonsignificant difference between
groups
#HR during meditation or
relaxation (P< .01)
(continued)
295
Table 2. (continued)
Study Reference Population Study Design Intervention Comparators Metabolic Measures
Cardiorespiratory and Other
Measures
Kesterson and Clinch
(1989)
124
Advanced meditators with
mean 28 years experience
(n ¼33); nonmeditators
(n ¼10)
Multiple practices on a
single occasion
Transcendental meditation
(TM); nonmeditators—
eyes closed relaxation
Baseline versus intervention;
comparison between the
groups
Similar significant drop in OC (P<
.002) during TM and relaxation;
nonsignificant difference between
groups
No traces of hypometabolism in
either group
Telles et al (1995)
117
Male meditators with >5
years experience (n ¼7)
Multiple practices on
2 occasions
Aum meditation session and
sitting relaxed session
(each session of 20 minutes
on different days)
Baseline rest versus
postmeditation and eyes
closed relaxation
Nonsignificant change in OC in
postmediative session compared
to baseline
#in HR (P< .001) during
meditation
Vempati and Telles
(1999)
101
Male yoga practitioner with
mean 23.9 months
experience (n ¼40)
Multiple practices on
2 occasions
Yoga-based isometric relaxa-
tion and supine rest (each
session of 10 minutes on
different days)
Baseline rest versus
postrelaxation and supine
rest
#of 23%(P< .001) in OC in post
yoga relaxation compared to
baseline; #of 7%in OC after
supine rest
#of 20.6%in BR (P< .01) post -
yoga relaxation
Vempati and Telles
(2002)
100
Male yoga practitioner with
mean 30.2 months
experience (n ¼35)
Multiple practices on
2 occasions
Yoga-based guided relaxation
session and supine rest
session (each session of 10
minutes on different days)
Baseline rest versus
postrelaxation and supine
rest
#of 25.2%in OC (P< .001) in post-
yoga relaxation compared to
baseline; #of 7%in OC after
supine rest
#of 9.7%in HR (P< .001), #in LF
(P< .05), "in HF (P< .05) after
relaxation compared to
baseline
Ray et al (2011)
95
Male yoga practitioners >6
years’ experience (n ¼20)
Multiple practices on
2 occasions
Hatha yoga session—
comprising variety of yoga
static postures
interspersed with
Shavasana,pranayamas, and
meditation practices;
VO
2max
session (each
session on different days)
Rest sitting (Sukhasana)
versus meditation and Aum
meditation
#of 15%in OC (P< .05) during
meditation and 4%during Aum
meditation compared to
Sukhasana
#of 37%in BR (P< .05) during
Aum meditation
Throll (1982)
136
Healthy nonpractitioner
males (n ¼39)
15 weeks of regular
practice, multiple
group
Meditation group (n ¼21);
transcendental meditation,
relaxation group (n ¼18);
progressive muscle
relaxation
Baseline versus immediately
after practice of first
session and then after 5,
10, and 15 weeks apart
Meditators displayed greater
reduction in OC during the
practice; reduction in OC more
prominent in relaxation overtime
of 15 weeks compared to
meditation
Reduction in HR in meditation
group prominent (P< .05)
compared to relaxation over
time
Abbreviations: OC, oxygen consumption; HR, heart rate; BPM, beats per minute; CO, carbon dioxide; BMR, basal metabolic rate; BR, breath rate; GSR, galvanic skin resistance; I:R:E, inspiration–retention–expiration; LF,
low frequency; HF, high frequency.
296
reported to be up to 15%less in regular yoga practitioners com-
pared to nonpractitioners, and oxygen consumption during sub-
maximal exercise is reported to decrease by 36%after 3 months
of regular yoga practice (Table 4).
Pranayama Practices and Oxygen Consumption
Table 1 summarizes 16 pranayama (yogic breathing) studies
that include a total of 143 participants and report wide varia-
tions in oxygen consumption. While oxygen consumption was
seen to increase with most breathing practices performed at
both fast (232 breath/min) and slow (1 breath/min) rates
(Table 1), a decrease in oxygen consumption from rest was also
seen in some slow breathing practices. The highest increase in
oxygen consumption was seen with extremely rapid Bhastrika
breathing, which involves rapid, forced thoracic inhalation and
exhalation. When Bhastrika was performed at a rate of 232
breath/min by 3 advanced practitioners, oxygen consumption
was reported to increase by 208%,
140
and increases in oxygen
consumption of 30%,24%,22%,17%, and 15%is reported
with Bhastrika performed at different rates and retention peri-
ods.
88,90,118,119
Increases in oxygen consumption of 12%
119
to
50%
87
are also reported with Kapalbhati breathing, which
involves forced rapid exhalation. Unilateral nostril breathing
(alternate nostril breathing, right nostril breathing, and left
nostril breathing) are reported to increase oxygen consumption
with a 150%increase during alternate nostril breathing
94
and
increases of 37%
96
to 18%
93,96
reported immediately after
alternate nostril breathing, right nostril breathing, and left nos-
tril breathing practices.
Oxygen consumption is also reported to increase with some
slow yoga breathing. Ujjayi breathing, which involves con-
trolled slow, deep breathing with long inhalation and exhala-
tion and gentle contraction of the glottis creating a soft
snoring sound,
141
has been consistently reported to increase
oxygen consumption, even at extremely slow rates. An increase
of 10%is reported in a single advanced practitioner while
practicing Ujjayi at a rate of 1 breath/min,
139
while further
studies report increases in oxygen consumption of 25%and
52%during Ujjayi with a 40-second retention (rate of 1.26
breath/min)
119
or with an inspiration–retention–expiration ratio
of 1:1:1.
92
An increase in oxygen consumption was also
reported with Ujjayi performed at different altitudes, with a
16%greater oxygen consumption observed in a single practi-
tioner at 3200 m elevation practicing Ujjayi breathing at 3
breath/min compared to practicing Ujjayi breathing at 520 m
elevation at 1.5 breath/min.
86
An increase in oxygen consump-
tion to 17%has also been reported in advance yoga practi-
tioners during slow paced breathing with and inspiration–
retention–expiration ratio of 1:4:2.
138
Only 4 studies (Table 1) report decreases in oxygen
consumption with pranayama. A decrease in oxygen consump-
tion of 4%,21%, and 19%is reported during slow Ujjayi
breathing at rates of 2 breath/min,
90
1.4 breath/min,
91
or with
an inspiration–retention–expiration ratio of 1:4:4.
92
A decrease
in oxygen consumption of 16%is also reported during Bhas-
trika breathing at 12 breath/min.
95
Yoga Meditation, Relaxation Practices, and Oxygen
Consumption
Table 2 summaries 15 studies with a total of 310 participants
that consistently report reduced oxygen consumption during
different meditation and relaxation practices. Two studies of
yogic relaxation practices report 25.2%and 23%reductions
in oxygen consumption compared to rest.
100,101
Transcendental
meditation is also reported to produce reductions of oxygen
consumption from rest, with 3 separate studies reporting reduc-
tions of 20%,17%, and 5%.
120-122
Reductions in oxygen con-
sumption from rest of 15%and 3.7%are also reported during
2 to 3 minutes of meditation.
95
Studies comparing meditation with non-yogic relaxation
techniques shows modest or no difference between interven-
tions. Four studies report no difference in oxygen consumption
between groups practicing Transcendental and those practicing
a control relaxation intervention,
123,124,134,136
while a further
study reports no significant reduction in oxygen consumption
from baseline rest during either after Om meditation or relaxed
sitting, despite reported reductions in heart rate and increases in
galvanic skin response.
117
Among the studies reporting reductions in oxygen consump-
tion, the most dramatic reductions were seen in 2 studies
involving advance yoga practitioners, with one study reporting
reductions in oxygen consumption of 40%below rest during a 4
hour stay in an air tight subterranean chamber
99
and another
study reporting reductions of 32%and 37%below rest during
2 separate 10-hour stays in an airtight box.
97
Reductions in
oxygen consumption of around 35%below rest are also
reported during meditation in a group of experienced yogis
(n ¼9).
138
An early study with 3 advanced yoga practitioners
further reports that during a prolonged stay in an airtight pit,
advanced meditators could tolerate ambient oxygen levels of
12.2%and carbon dioxide levels of 7.3%.
98
Asana/Integrated Yoga Practices and Oxygen
consumption
Table 3 presents 13 studies with a total of 272 subjects that con-
sistently report increases in oxygen consumption with different
yoga asanas (postures). The most dramatic increase was seen
in a group of 21 male practitioners who experienced a 383%
increase in oxygen consumption while performing cobra
pose.
104
Increases in oxygen consumption were also reported
with warrior III pose (300%),
125
plough pose 2 (160%),
95
Hero
pose (159%),
103
headstand pose (68%),
85
and accomplished
pose (27%).
102
Over the course of a yoga session, oxygen consumption has
been reported to increase by 100%with Ashtanga yoga,
126
114%with Hatha yoga,
131
133%with Thai yoga,
137
and
144%with Iyenger yoga.
125
Three studies have examined oxy-
gen consumption during Sun Salutation (a dynamic sequence
Tyagi and Cohen 297
297
Table 3. Summary of Studies Reporting Changes in Oxygen Consumption With Asana, Integrated Practice(s).
Study Reference Population Study Design Intervention Comparators Metabolic Measures
Cardiorespiratory and Other
Measures
Rao (1962)
85
Male yoga practitioners
(n ¼6)
Single practice on
a single
occasion
Head stand posture Baseline recumbent and
standing erect versus
head stand posture
"of 68%and 48%in OC during headstand
posture compared to recumbent position
and standing erect, respectively
Rai and Ram
(1993)
103
Male yoga practitioners
(n ¼10)
Single practice on
a single
occasion
Virasana (hero pose); Subgroup
1—with resting breath rate
>10 breath/min (n ¼6);
Subgroup 2—with resting
breath rate <5 breath/min
(n ¼4)
Baseline Shavasana versus
Virasana
Subgroup 1: "of 159%in OC (P< .005) and "
of 223%in CO
2
exhalation (P< .01)
during Virasana in group with BR >10
breath/min; Subgroup 2: "of 163%in OC
(P< .05) and "of 166%in CO
2
exhalation
during Viransana in group with BR <5
breath/min
"of 60%(P< .0005) and 43%(P<
.001) in HR in subgroups 1 and
2, respectively
Rai et al (1994)
102
Male yoga practitioners
(n ¼10)
Single practice on
a single
occasion
Siddhasana (accomplished pose);
Subgroup 1—with resting
breath rate >10 breath/min
(n ¼6); Subgroup 2—with
resting breath rate <5 breath/
min (n ¼4)
Baseline Shavasana versus
Siddhasana
Subgroup 1: "of 27%in OC (P< .01) and "of
31%(P< .01) in CO
2
exhalation during
Siddhasana in group with >10 breath/min;
Subgroup 2: "of 21%in OC and "of 25%
in CO
2
exhalation during Siddhasana in
group with >5 breath/min
"of 13%(P< .01) and of 15%(P<
.001) in HR in subgroups 1 and
2, respectively
Sinha et al
(2004)
104
Male yoga practitioners
(n ¼21)
Single practice on
a single
occasion
Sun salutation (SS)—12 dynamic
postures preceded and
followed by Shavasana
Comparison between
each individual posture
of SS and Shavasana
"of 207%in OC during complete session of
SS compared to Shavasana;"of 383%
during 8th pose (Cobra) compared to
Shavasana; OC higher (P< .05) during
backward bending poses (2nd, 4th, 5th,
and 8th poses) compared to forward
bending poses (3rd and 11th)
HR range—83.5 BPM to 101.6
BPM during entire SS
compared to 60.2 BPM during
Shavasana
Blank (2006)
125
Female yoga practitioners
(n ¼15)
Single practice on
a single
occasion
Iyenger yoga posture sequences—
warm-ups, 20 individual pos-
tures and releasing poses with
Shavasana
Comparison between
each individual posture
and postures divided in
sets (back arch,
inversion, standing,
supine, and seated)
versus Shavasana
"of OC during standing, back arc, and
inversion poses (P< .05) compared to
supine and seated posture; "of 300%of
OC (P< .05) during warrior pose III
compared to Shavasana;"of 144%in OC
during 65 minutes yoga session compared
to Shavasana
Back arch poses 75%of HR
max
Hagins et al
(2007)
126
Yoga practitioners with
>1 year experience in
yoga; 2 males, 28
females (n ¼20)
Multiple practices
on a single
occasion
Ashtanga yoga session of 56
minutes—Warm-up, sun salu-
tation, and non-sun salutation
poses; mild and moderate
submaximal exercise—tread-
mill walk at 2 mph and 3 mph
Baseline rest and mild to
moderate exercise
versus yoga session;
sun salutation versus
non-sun salutation
poses
"of 100%in OC (P< .0001) during yoga
session compared to rest; OC 14%lower
during yoga sequence compared to mild
exercise and 33%lower to moderate
exercise (Ps < .0001); OC 25%higher (P<
.001) during sun salutation compared to
non-sun salutation poses
"of 31%in HR (P< .0001) during
yoga compared to rest; yoga
sequence 49.4%of HR
max
;HR
15%higher during sun
salutation compared to non-
sun salutation poses
Telles et al
(2000)
105
Male yoga practitioner
with >3 months
experience (n ¼40)
Multiple practices
on 2 occasions
Cyclic meditation (CM) session
and Shavasana session (each
session on different days)
Baseline rest versus
postpractice session of
CM and Shavasana
#of 32%in OC (P< .001) post-CM; #of 10%
in OC (P< .05) post-Shavasana compared
to baseline
#of 28%(P< .001) and 15%(P<
.05) in BR during postsession
in CM and Shavasana,
respectively
Sarang and Telles
(2006)
106
Male yoga practitioner
with >3 months
experience (n ¼50)
Multiple practices
on 2 occasions
Cyclic meditation session (CM)
(divided into 4 phases) and
Shavasana session (each
session on different days)
Baseline rest versus CM
session and Shavasana
session; baseline rest
versus postpractice
session of CM and
Shavasana
"of 31.3%in OC (P< .001) during active
phases of CM; #of 19.4%in OC (P< .001)
post-CM compared to baseline; #of 7%in
OC (P< .001) post-Shavasana; nonsignifi-
cant change in OC during Shavasana
compared to baseline
"up to 21%in BR (P< .001)
during CM and #of 7%(P<
.05) in BR post-CM compared
to baseline
(continued)
298
Table 3. (continued)
Study Reference Population Study Design Intervention Comparators Metabolic Measures
Cardiorespiratory and Other
Measures
DiCarlo et al
(1995)
132
Yoga practitioners with
>1 year experience
(n ¼10)
Multiple practices
on 2 occasions
Hatha yoga—12 standing postural
sequence session; submaximal
exercise session treadmill walk
at 4 mph and VO
2max
session
(each session on different
days)
Submaximal exercise and
VO
2max
session versus
Hatha yoga routine
session
OC 26%lower during yoga sequences (P<
.05) compared to submaximal exercise in
first 8th minute and remained lower
during complete session; yoga session
34%of VO
2max
and submaximal exercise
46%of VO
2max
HR 4%higher in during yoga
sequence (P< .05) compared
to submaximal exercise in 8th
minute and remained higher
during complete yoga session
Carroll et al
(2003)
127
Yoga practitioners with
>3 months experience
(n ¼13)
Multiple practices
on 2 occasions
Vinyasa yoga sequences and
VO
2max
VO
2max
versus Vinyasa
yoga
Yoga session >50%of VO
2max
Yoga session >77%of HR
max
Clay et al
(2005)
131
Yoga practitioners with
>1 month experience
(n ¼30); 2 males, 28
females
Multiple practices
on 2 occasions
Hatha yoga session—Warm-ups,
sun salutation, non-sun saluta-
tion, and cool down poses;
submaximal exercise—tread-
mill walk at 3.5 mph and
VO
2max
session (each session
on different days)
Chair sitting, submaximal
exercise and VO
2max
session versus Hatha
yoga session
"of 114%in OC (P< .05) during yoga
session compared to chair sitting; OC
54%lower (P< .05) during yoga session
compared to submaximal exercise; yoga
session 14.5%and submaximal exercise
44.8%of VO
2max
;OC82%higher (P<
.05) during sun salutation compared to
non-sun salutation
"of 24%in HR (P< .06) during
yoga session compared to
chair sitting; HR 21%lower (P
< .05) during yoga session
compared to submaximal
exercise; HR 20%higher (P<
.05) during sun salutation
compared to non-sun
salutation
Buranruk et al
(2010)
137
Middle aged non-yoga
practitioners (n ¼17)
Multiple practices
on 2 occasions
Thai yoga session—warm-ups,
sitting, standing, and lying
poses; VO
2max
(each session
on different days)
VO
2max
session and
baseline rest versus
Thai yoga session;
calorimetry
"of 133%during yoga session compared to
rest; yoga session 35.5%of VO
2max
;OC
46%higher (P< .0001) during standing
poses compared to sitting
"of 16.6%in HR during Thai yoga
compared to rest; HR during
yoga sequence 50%of HR
max
;
HR 10.6%higher (P< .0001)
during standing poses
compared to sitting
Ray et al (2011)
95
Male yoga practitioners
with >6 years’
experience (n ¼20)
Multiple practices
on 2 occasions
Hatha yoga session—comprising
variety of yoga static postures
interspersed with shavasana,
pranayamas, and meditation
practices; VO
2max
session
(each session on different
days)
VO
2max
session and
shavasana versus
individual yoga static
postures
"of 160%in OC (P< .05) during plough
pose-2; "of 156%in OC (P< .05) during
bow pose compared to shavasana; Bow,
plough-1, plough-2, and shoulder stand
pose 26.5%, 25.9%, 24.6%, 22.7%,
respectively, of VO
2max
;shavasana 9.9%of
VO
2max
"of 108%in BR (P< .05) during
ploughs 1 and 2 compared to
shavasana
Abbreviations: OC, oxygen consumption; CO
2
, carbon dioxide; BR, breath rate; HR, heart rate; BPM, beats per minute.
299
Table 4. Summary of Studies Reporting Changes in Oxygen Consumption With Yoga and Physical Activity.
Study Reference Population
Study Design and
Duration Intervention Comparators Metabolic Measures
Cardiorespiratory and Other
Measures
Salgar et al
(1975)
107
Healthy males (n ¼38) Multiple practices on
single occasion
6 months of regular lotus posture
(n ¼10); resistance training
(n ¼12); sedentary lifestyle
(n ¼16)
Comparison between groups
during mild and moderate level
ergometer exercise
At mild-level exercise the OC was low-
est in lotus group followed by exerci-
sers and nonexercisers; at moderate-
level exercise OC lowest in exercisers
followed by lotus and nonexerciser
groups
Bhatnagar et al
(1978)
108
Healthy non-yoga practi-
tioners (n ¼20)
6-Month cohort study of
multiple practices
Regular integrated yoga practices Pre-yoga intervention submaxi-
mal exercise versus fixed
intensity submaximal exercise
after 1, 3, and 6 months of yoga
practice
Progressive increase in OC during
submaximal exercise (P< .05) in 3 and
6 months compared to pre-
intervention; no significant increase
after 1 month
#in resting body core
temperature (P< .05, P<
.001, P< .001) in 1, 3, and 6
months compared to pre-
intervention
Joseph et al
(1981)
109
Healthy male non-yoga
practitioners (n ¼10)
3-Month cohort study of
multiple practices
Regular integrated yoga practices Pre-yoga intervention rest
versus post-yoga
intervention rest
Nonsignificant decrease in resting OC #of 7.8%in HR (P< .001); #in
SBP/DBP (P< .01); #in blood
glucose (P< .05) and blood
cholesterol (P< .01)
Raju et al
(1986)
110
Non-yoga practitioners
(n ¼12)
3-Month cohort study of
multiple practices
Regular integrated yoga practice Pre-yoga intervention rest versus
post-yoga intervention rest;
Pre-yoga intervention sub-
maximal exercise versus sub-
maximal exercise after 20 days
and 3 months of yoga practice
Nonsignificant change in resting OC in
either gender; #of 41%in OC (P<
.05) during submaximal exercise after
20 days and #of 36%in OC (P< .05)
during submaximal exercise after 3
months in males only
#of 65.5%in blood lactate (P<
.05) in males at same exercise
workload after 3 months; no
significant changes in females
Balasubramanian
and Pansare
(1991)
116
Healthy non-yoga
practitioners (n ¼17)
6-Week cohort study of
multiple practices
Integrated yoga practice Pre-yoga intervention VO
2max
versus post-yoga intervention
VO
2max
"of 17%in VO
2max
(P< .005)
Raju et al
(1997)
111
Healthy female non-yoga
practitioner (n ¼6)
4-Week cohort study of
multiple practices
Integrated yoga practice Pre-yoga intervention VO
2max
versus exercise versus post-
yoga intervention VO
2max
#of 14%in OC (P< .05) per unit of work
load; "of 21%in maximal work load (P
< .05) in post-yoga intervention com-
pared to pre-yoga intervention
#of 6%in HR (P< .05) post-
yoga intervention; #in body
fat and weight (P< .05)
Tran et al
(2001)
128
Healthy non-yoga practi-
tioners (n ¼10)
8-Week cohort study of
multiple practices
Integrated yoga session Pre-yoga intervention VO
2max
versus post-yoga intervention
VO
2max
"of 10%in VO
2max
(P< .01) "in muscular strength (P< .05),
muscular endurance (P<
.01), and flexibility (P< .001)
Ramos-Jime
´nez
et al
(2011)
142
Female, middle-aged, and
old yoga practitioners
with >3 years’ experi-
ence (n ¼13)
11-Week cohort study of
multiple practices
Integrated intensive yoga training
(middle-aged practitioners with
mean age 43.2 years ¼4; older
practitioners with mean age
62.2 years ¼9)
Pre-yoga intervention VO
2max
versus post-yoga intervention
VO
2max
"of 3%in VO
2max
(P< .05) in middle-
aged group and "of 17%in VO
2max
(P< .05) in older group
Increase in HR
max
(P< .05) in
both groups; improvement in
lipid profile and blood
glucose and BMI (Ps < .05) in
both groups
Raju et al
(1994)
112
Healthy male non-yoga
practitioners (n ¼28)
24-Month NRCT of mul-
tiple practices
Yoga group—Pranayama and
shavasana along with regular
sports workouts (n ¼14);
Control—Regular sports
workouts (n ¼14) (each group
further subgrouped into Phases
1and2ofsubmaximal(n¼12)
and maximal exercise (n ¼16)
of duration 12 months and 24
months, respectively)
Pre-intervention rest versus
post-yoga intervention rest
(phases 1 and 2); pre-
intervention submaximal and
maximal exercise versus post-
yoga intervention submaximal
and maximal exercise
Phase 1—#of 38%in OC at resting
state in yoga group; #of 51%in OC
(P< .05) per unit work load with
submaximal exercise in yoga group
after intervention; no change in
controls either in rest or during
exercise; Phase 2—No change in
resting OC in either yoga or control
group; #of 34%in OC (P< .05) per
unit work load with maximal exercise
in yoga group after intervention; no
change in control
Phase 1—#of 49%in resting
blood lactate (P< .01) in
yoga group; Phase 2—#of
37%in resting blood lactate
(P< .05) in yoga group; #of
61%in exercise blood
lactate after 24 months
compared to pre-
intervention in yoga group
Ray et al
(2001)
115
Healthy male non-yoga
practitioners (n ¼28)
6-Month RCT of multiple
practices
Yoga group—integrated yoga
practices (n ¼17); physical
training as per army program
(n ¼11)
Pre-intervention VO
2max
versus
postintervention VO
2max
"of 6.7%in VO
2max
(P< .05) in yoga group;
no change in physical training group
#in body fat and body weight
(Ps < .01) in yoga group
(continued)
300
Table 4. (continued)
Study Reference Population
Study Design and
Duration Intervention Comparators Metabolic Measures
Cardiorespiratory and Other
Measures
Nayar et al
(1975)
113
Healthy male non-yoga
practitioners (n ¼53)
12-Month RCT of multi-
ple practices
Yoga group—integrated yoga
with regular physical training
(n ¼18);
Athletic group—athletics with
regular physical training
(n ¼17); Control—regular
physical training (n ¼18)
Pre-intervention rest versus
postintervention rest; pre
intervention submaximal ver-
sus postintervention submaxi-
mal exercise
Nonsignificant change in OC at rest in
either group; nonsignificant changes in
OC during submaximal exercise in
either group
"of 29%in vital capacity (P<
.01) and 5%in FEV
1
(P< .05)
in yoga group; "of 46%in
breath-hold time (P< .01) in
yoga group
Selvamurthy
et al
(1988)
114
Healthy male non-yoga
practitioners (n ¼30)
6-Month RCT of multiple
practices
Yoga group—integrated training
(n ¼15); Physical training (PT)
group—running, games,
flexibility, and pull-ups (n ¼15)
Pre-yoga intervention submaxi-
mal exercise versus post-yoga
intervention submaximal
exercise
#of 5.7%in OC (P< .05) in yoga group;
nonsignificant change in PT group
#of 7%in HR (P< .01) in yoga
group
Bowman et al
(1997)
133
Sedentary healthy elderly
subjects >62 years
(n ¼40)
6-Week RCT of multiple
practices
Yoga group—integrate yoga
(n ¼20); aerobic group—
bicycle-based aerobic training
(n ¼20)
Pre-yoga intervention submaxi-
mal exercise versus post-yoga
intervention with submaximal
exercise
"of 13%in VO
2max
(P< .01) in yoga
group and "of 24%in VO
2max
(P< .01) in aerobic group
#of 11.6%in HR (P< .05) in
yoga group; no change in
aerobic group; "in
baroreflex sensitivity (P<
.01) in yoga group; no
significant change in HRV in
either groups
Pullen et al
(2008)
130
Patients with congestive
heart failure (CHF)
(n ¼19)
8-Week RCT of multiple
practices
Yoga group—integrated yoga
practices along with standard
medical therapy (n ¼9);
Control—standard medical
therapy with general
awareness (n ¼10)
Pre-intervention VO
2max
versus
postintervention VO
2max
"of 17%in VO
2max
(P< .02) in yoga
group; no change in controls
Improvement of 25.7%in quality
of life scores (P< .005) in yoga
group
Tracy and Hart
(2012)
129
Sedentary healthy non-
yoga practitioners
(n ¼21)
8-Week RCT of multiple
practices
Bikram yoga—26 series of
postures in heated (35Cto
40C) humidified studio
(n ¼10); waitlist control
(n ¼11)
Pre-yoga intervention VO
2max
versus post-yoga intervention
VO
2max
No change in VO
2max
after yoga training "of 23.8%in sit and reach
score (P< .001) and
shoulder flexibility (P< .05)
with yoga
Chaya et al
(2006)
70
Non-yoga (NY) and regu-
lar yoga practitioners
(YP) with >6 months
experience (n ¼104)
Multiple practices on a
single occasion
YP—regular integrated yoga
practice (n ¼55); NY (n ¼49)
Yoga practitioners versus non-
yoga practitioners at rest
(basal state)
Basal OC—19.3%less in female YPs and
10.7%less in male YPs (Ps < .001)
compared to NYs; Basal CO
2
—12.7%
less in female YPs and 14.3%less in
male YPs (Ps < .05) compared to NYs;
BMR in YP 15%less (P< .001) in YP
compared to NY and 13%less than the
predicted by WHO/FAO/UNU
BR 19.6%less (P< .001) in
female YPs and 19%(P<
.001)inmaleinYPs
compared to NYs
Chaya and
Nagendra
(2008)
71
Non-yoga (NY) and regu-
lar yoga practitioners
(YP) with >6 months
experience (n ¼88)
Multiple practices on a
single occasion
YP—regular integrated yoga
practice (n ¼51); NY (n ¼37)
Yoga practitioners versus non-
yoga practitioners at rest at 6
AM (basal) and 9 PM (pre-sleep)
Basal OC—22%less (P< .005) in female
YPs and 10.7%less (P< .05) in male YPs
compared to NY females and males,
respectively; Pre-sleep OC—17%less
in female YPs and 6.7%in male YPs
(nonsignificant) compared to NY
females and males, respectively; Basal
CO
2
—15.3%less in female YPs and
14.8%less in male YPs (Ps < .05) com-
pared to NYs; Pre-sleep CO
2
—13.2%
less in female YPs and 8.3%in male YPs
compared to NYs
BR 23.3%less (P< .005) in
female YPs and 15.6%less
(P< .05) in male YPs during
morning compared to NYs
Abbreviations: OC, oxygen consumption; HR, heart rate; SBP, systolic blood pressure; DBP, diastolic blood pressure; BMI, body mass index, NRCT, nonrandomized controlled trial; RCT, randomized controlled trial; FEV
1
,
forced expiratory volume in 1 second; HRV, heart rate variability; CO
2
, carbon dioxide exhalation; BMR, basal metabolic rate; BR, breath rate.
301
of 12 postures) and report that oxygen consumption increased
205%above resting levels
104
and 25%
126
and 81%
131
above the
levels during static postures.
The reported increases in oxygen consumption seen with
yoga practices are less than observed with maximal or submax-
imal exercise. Oxygen consumption during Thai yoga is reported
to be 35.5%of VO
2max
,
137
Vinyasa yoga, 50%,
127
bow posture,
26.5%,andShavasana (supine pose), 9.9%,
95
of VO
2max
.Simi-
larly, Iyenger,Ashtanga,andHatha yoga sequences have been
shown to be of lower intensity than submaximal exercise, having
oxygen consumption that is 26%,33%,and54%lower than
oxygen consumption during treadmill walking at 4 mph,
132
3
mph,
126
or 3.5 mph,
131
respectively.
While oxygen consumption is reported to increase during a
yoga session, there are reports that oxygen consumption may
fall below presession levels immediately after certain practices.
During cyclic meditation, which involves a series of postural
sequences interspersed with periods of relaxation, oxygen con-
sumption is reported to increase by up to 55%during the active
phase and then fall to 19%below presession levels in the
immediate postsession period.
106
Similar results are reported
in a further study, which reports a 32%decrease in oxygen
consumption immediately after cyclic mediation.
105
Regular Yoga Practice, Physical Activity, and Oxygen
Consumption
Table 4 presents 16 studies involving 516 participants that
measured oxygen consumption at rest or during physical activ-
ity (submaximal and maximal) after 1 month to 24 months of
integrated yoga practice (including asana,pranayama, and
relaxation) along with 2 studies comparing oxygen consump-
tion at rest in yoga and non-yoga practitioners
70,71
and 1 study
comparing oxygen consumption between groups who regularly
practiced lotus posture and groups of regular exercisers or
healthy sedentary subjects.
107
Most of these studies report that regular yoga practice leads
to progressive reductions in oxygen consumption over time. In
a 3-month cohort study, yoga practice was found to reduce
oxygen consumption during submaximal exercise by 36%
compared to baseline levels.
110
A randomized trial involving
male soldiers found that 6 months of yoga practice (n ¼15)
reduced oxygen consumption during submaximal exercise by
5.7%(P< .05) compared to no change in a physical training
group (n ¼15),
114
while a nonrandomized study reports that
12 months of regular yoga practice with regular sports activity
improved submaximal work efficiency in athletes with 51%
greater work output per liter of oxygen consumed, compared
to no change in regular sports activity group.
112
VO
2max
was also reported to increase with regular yoga prac-
tice, ranging from 6 weeks to 6 months in diverse populations. A
3%increase in VO
2max
is reported in the cohort of middle-aged
yoga practitioners who practiced intensive yoga for 11 weeks
142
and 7%increase in VO
2max
in a cohort of yoga navies who
practiced integrated yoga for 8 weeks.
128
Similarly, up to 7%
increment of VO
2max
is reported in a randomized trial of 6
months in male soldiers with integrated yoga (n ¼17) compared
to no change in a physical training group (n ¼11),
115
and a 13%
(P<.01)increaseinVO
2max
is reported in elderly subjects in a
randomized trial after 6 weeks of yoga with practice (n ¼20),
similar to significant increase with aerobic training (n ¼20).
133
Increases in VO
2max
of approximately 17%are also reported
after yoga practice in 2 cohort studies including a 6-week study
of healthy subjects (n ¼17)
116
and an 11-week study of elderly
yoga practitioners (n ¼9).
142
Similar increases in oxygen con-
sumption are reported in an 8-week randomized controlled trial
of patients with congestive heart failure who practiced yoga
(n ¼9), compared to no change in a standard medical therapy
group (n ¼10).
130
A further cohort study of female physical
trainers found that 1 month of yoga practice led to 14%greater
maximal work efficiency.
111
Maximal work efficiency was
also seen to improve in a nonrandomized controlled trial by
34%in athletes after 24 months of regular yoga practice com-
pared to a control group practicing physical exercise.
112
Not all the studies report improvement in oxygen consump-
tion or work efficiency with regular yoga practice. A 12-month
randomized study reports no change in oxygen consumption
during submaximal exercise in either a yoga or aerobic training
group.
113
In another randomized study, no change in VO
2max
is
reported after 8 weeks in a yoga practice group (n ¼10) com-
pared to a no-intervention control group (n ¼11).
129
Similarly,
two 3-month cohort studies report no change in oxygen con-
sumption at rest after regular yoga practice,
109,110
and similar
results are reported in a 12-month randomized controlled
trial.
113
In contrast to most of the above-mentioned studies, one
small cohort study reported increased oxygen consumption
during submaximal exercise after 6 months of regular yoga
practice in healthy subjects despite an observed reduction in
resting core body temperature.
108
When examining oxygen consumption at rest, 2 studies
report basal oxygen consumption to be significantly less in reg-
ular yoga practitioners compared to non-yoga practitioners.
One study
70
reports that regular yoga practitioners had basal
metabolic rate 13%less than predicted based on the FAO/
WHO/UNU equation
143
and that oxygen consumption during
basal conditions was significantly less in regular yoga practi-
tioners compared to non-yoga practitioners. Similar results
were reported in the second study, which report that regular
yoga practitioners had basal metabolic rate that was 17.8%less
than non-yoga practitioners.
71
Discussion
Studies published to date suggest that yoga practices can have
profound metabolic effects producing both significant increases
and decreases in oxygen consumption. Like other physical activ-
ity, physical yoga postures can increase oxygen consumption
dramatically, yet yoga practices do not involve maximal
exertion. For example, dynamic postures such as cobra pose are
reported to increase oxygen consumption by 383%or around
1220 mL/min, which is less than half that produced with maxi-
mal exercise in the average untrained healthy male.
3
The most
302 Journal of Evidence-Based Complementary & Alternative Medicine 18(4)
dramatic change seen with yoga is reduction of oxygen con-
sumption, with reports of yoga practices downregulating the
sympathetic nervous system and producing modest reductions
in oxygen consumption comparable to practices such as progres-
sive muscle relaxation, closed eyes relaxation, and listening to
music,
123,124,134,136
as well as reports of dramatic reductions
up to 40%.
99
This suggests that yoga may downregulate the
hypothalamic–pituitary–adrenal axis and the sympathetic activ-
ity and therefore promote relaxation and stress relief.
Regular yoga practice also appears to have a training effect,
with regular yoga practitioners consistently showing signifi-
cant reductions in oxygen consumption during normal physical
activity compared to non-yoga practitioners. Thus, unlike other
physical training, which generally increases resting metabolic
rate,
144,145
regular yoga practice is reported to decrease resting
oxygen consumption to levels lower than predicted by the
FAO/WHO/UNU equation.
70
This may be due to regular phys-
ical training producing an increase of muscle mass, which
requires greater oxygen consumption supply at rest, whereas
yoga training may instead increase efficiency of mitochondrial
oxidative phosphorylation and reduce oxygen demand.
Yoga practices are also reported to shift lactate threshold
(anaerobic threshold) and improve work efficiency, indicating
aerobic capacity and reduced muscle fatigue to a greater degree
compared to physical activity.
112
These results are supported
by a randomized crossover trial documenting reduction in
blood lactate, heart rate, and blood pressure with regular yoga
practice.
146
A recent review of yoga and exercise found that yoga may
be as effective as or better than aerobic exercise at improving
a variety of health-related outcome measures in both healthy
and diseased populations.
147
Despite multiple studies demon-
strating the benefits of yoga in various clinical conditions, only
one small study examined the effects of yoga and oxygen con-
sumption in a clinical population. This study reported increased
aerobic capacity (VO
2max
) in patients with congestive heart
failure after practicing yoga postures, breathing techniques,
and meditation over a period of 8 weeks.
130
Previous research
also suggests that instruction on respiration and relaxation, in
addition to physical exercise, enhances respiratory sinus
arrhythmia and slows heart rate and breath rate in myocardial
infarction patients during rehabilitation
148
and that slow rhyth-
mic respiration can be used as a therapeutic tool for anxiety,
149
hypertension,
150,151
and asthma.
152
Due to the wide variety of
yoga practices and styles, further research is required to deter-
mine the most appropriate practices for different clinical condi-
tions. Typical yoga sessions of different styles appear to differ
in exercise stimulus, resulting in varied increase in oxygen
consumption
125,126,131,137
with profound increases reported
during dynamic posture sequences compared to static posture
sequences.
126,131
Different yoga practices and styles, however,
are likely to have different health and fitness benefits.
153,154
It appears that breath rate and retention periods are critical in
determining oxygen consumption and that yoga practitioners
are able to vary their breath rate widely with reported breath
rates ranging from 1 breath/min to more than 230 breath/min.
Oxygen consumption is also reported to paradoxically increase
by up to 10%despite breath rates of only 1 breath/min. The
most profound changes in oxygen consumption with breathing
techniques are seen in advanced yoga practitioners who are
reported to increase their oxygen consumption by 208%and
their carbon dioxide exhalation by 395%when performing
Bhastrika breathing at 232 breath/min, or decrease their oxy-
gen consumption by 16%when performing the same type of
breathing at 12 breath/min. Similarly, altering the retention
period during Ujjayi breathing is reported to either increase
oxygen consumption by up to 52%when performed with a
short retention period with an inspiration–retention–expiration
ratio of 1:1:1 or decrease by 19%when the same type of breath-
ing is performed with a longer retention period of inspiration–
retention–expiration ratio of 1:4:4. Ultradian rhythms in nasal
cycles and unilateral nostril breathing practices may also influ-
ence oxygen consumption with alternate nostril breathing
being reported to increase oxygen consumption by up to
150%.
94
Advanced yoga practitioners appear to be able to exert
extraordinary conscious manipulation of their metabolic and
autonomic functions,
155,156
with reports of yogis being able
to tolerate ambient carbon dioxide levels of more than 7%and
oxygen levels less than 12%.
98
There are further reports of
advanced yogis being able to reduce oxygen consumption by
40%while meditating in an airtight pit
99
and survive 8 days
in an airtight pit with an unrecordable electrocardiogram.
157
These reports appear inexplicable, yet are similar to reports
of advanced Zen meditators being able to decrease oxygen con-
sumption up to 20%and dramatically reduce their respiratory
rate to 1.5 to 2 breath/min during Zazen meditation, Tum-mo
meditators being able to increase or decrease their oxygen con-
sumption by more than 60%during seated meditation,
158
and
reports of modern free divers being able to hold their breath
for more than 10 minutes while diving to depths of more than
200 m.
159
So far, these extreme feats of metabolic control are
poorly documented and limited to single case studies or small
cohorts. They therefore require further investigation and docu-
mentation as they may provide clues about extending the limits
of human endurance and metabolic control.
This review suggests that yoga can have profound metabolic
effects with a consistent picture emerging from experimental,
cohort, nonrandomized, and randomized controlled trial
studies. Yet most of the studies are of poor methodological
quality and do not provide adequate reporting of the study
design, study population, yoga practices, methods of measure-
ments, or statistical methods. Furthermore, most studies were
performed in India (n ¼35) and included only small numbers
of adult male yoga practitioners without matched comparison
groups. Furthermore, there are 2 randomized controlled trails
of healthy people that report no change in oxygen consumption
with yoga despite significant changes in other physiological
measures. Of these, a controlled trial (n ¼10) reported signif-
icant improvements in flexibility with yoga but no change in
maximal aerobic capacity,
129
while another controlled trail
(n ¼18) reported improvements in respiratory variables and
Tyagi and Cohen 303
breath hold time but no change in oxygen consumption during
submaximal exercise with yoga.
113
A further cohort study (n ¼
10) reported significant improvements in biochemical and
anthropometric parameters after 3 months of yoga practice but
did not find any change in oxygen consumption.
109
The small sample sizes, variable practices, and limited, non-
clinical populations involved in the reviewed studies make it
difficult to generalize results to wider populations or make
definitive statements about specific practices. Thus, more
rigorous studies with larger samples and standardized practices
are required to determine the role of yoga in modulating
oxygen consumption and determine if the reported results can
be reproduced in non-Indian, female, adolescent, and non-
yoga-practicing populations as well as in different clinical
conditions. The reports of advanced yogis performing extraor-
dinary feats also warrant further investigation using modern
equipment and research methodologies.
Conclusion
Research to date on yoga and metabolism includes many
heterogeneous yoga practices in studies of poor methodological
quality. This research suggests that yoga practices can produce
dramatic changes in oxygen consumption and metabolism and
that regular yoga practice may lead to reduced resting meta-
bolic rate. Research further suggests that different yoga pos-
tures and breathing practices, which involve the control of
respiratory rate and retention periods, may produce markedly
different metabolic effects with reductions in oxygen consump-
tion being more dramatic than increases. The volitional control
over autonomic functions and increased metabolic endurance
demonstrated by advanced yoga practitioners warrant further
investigation. Rigorous research on standardized practice is
required to determine the relevance of yoga practices in various
clinical conditions.
Authors’ Note
This article was prepared as part of Anupama Tyagi’s PhD
research.
Acknowledgement
The work for this article was performed at RMIT University. The
authors would like to acknowledge the assistance of RMIT University
biomedical librarian Savita Hazari for her help in conducting the
searches and sourcing and obtaining articles.
Author Contributions
Anupama Tyagi was responsible for conducting the literature searches,
preparing the tables, and writing the first draft of the article. Marc
Cohen was responsible for conceiving the article, categorizing the
papers, and assisting in writing the article and reviewing drafts.
Declaration of Conflicting Interests
The authors declared no potential conflicts of interest with respect to
the research, authorship, and/or publication of this article.
Funding
The authors received no financial support for the research, authorship,
and/or publication of this article.
Ethical Approval
As this article represents a systematic review of literature and no human
or animal experimentation, no ethics review was sought or required.
References
1. Haugen HA, Chan LN, Li F. Indirect calorimetry: a practical
guide for clinicians. Nutr Clin Pract. 2007;22:377-388.
2. Bonnet MH, Arand DL. Insomnia, metabolic rate and sleep
restoration. J Intern Med. 2003;254:23-31.
3. McArdle WD, Katch FI, Katch VL. Exercise Physiology:
Nutrition, Energy, and Human Performance. Philadelphia, PA:
Wolters Kluwer; 2010.
4. Olshansky SJ, Rattan S. What determines longevity: metabolic
rate or stability. Discov Med. 2005;5:359-362.
5. Epel ES. Psychological and metabolic stress: a recipe for acceler-
ated cellular aging? Hormones. 2009;8:7-22.
6. Levine JA. Measurement of energy expenditure. Public Health
Nutr. 2005;8:1123-1132.
7. Glass S, Dwyer GB. ACSM’S Metabolic Calculations Handbook.
Philadelphia, PA: Lippincott Williams & Wilkins; 2007.
8. Jumpertz R, Hanson RL, Sievers ML, Bennett PH, Nelson RG,
Krakoff J. Higher energy expenditure in humans predicts natural
mortality. J Clin Endocrinol Metab. 2011;96:E972-E976.
9. Ruggiero C, Metter EJ, Melenovsky V, et al. High basal metabolic
rate is a risk factor for mortality: the Baltimore Longitudinal
Study of Aging. J Gerontol A Biol Sci Med Sci. 2008;63:698-706.
10. Carroll D, Phillips AC, Balanos GM. Metabolically exaggerated
cardiac reactions to acute psychological stress revisited. Psycho-
physiology. 2009;46:270-275.
11. Balanos GM, Phillips AC, Frenneaux MP, et al. Metabolically
exaggerated cardiac reactions to acute psychological stress: the
effects of resting blood pressure status and possible underlying
mechanisms. Biol Psychiatry. 2010;85:104-111.
12. Carroll D, Rick Turner J, Hellawell JC. Heart rate and oxygen
consumption during active psychological challenge: the effects
of level of difficulty. Psychophysiology. 1986;23:174-181.
13. Turner JR, Carroll D. Heart rate and oxygen consumption during
mental arithmetic, a video game, and graded exercise: further
evidence of metabolically-exaggerated cardiac adjustments?
Psychophysiology. 1985;22:261-267.
14. Schmidt WD, O’Connor PJ, Cochrane JB, Cantwell M. Resting
metabolic rate is influenced by anxiety in college men. J Appl
Physiol. 1996;80:638-642.
15. Poehlman ET, Scheffers J, Gottlieb SS, Fisher ML, Vaitekevicius
P. Increased resting metabolic rate in patients with congestive
heart failure. Ann Intern Med. 1994;121:860-862.
16. Bernardi M, Macaluso A, Sproviero E, et al. Cost of walking and
locomotor impairment. J Electromyogr Kinesiol. 1999;9:149-157.
17. Hommes MJ, Romijn JA, Endert E, Sauerwein HP. Resting
energy expenditure and substrate oxidation in human immunode-
ficiency virus (HIV)-infected asymptomatic men: HIV affects
304 Journal of Evidence-Based Complementary & Alternative Medicine 18(4)
host metabolism in the early asymptomatic stage. Am J Clin Nutr.
1991;54:311-315.
18. Wouters EFM. Nutrition and metabolism in COPD. Chest J.
2000;117(5 suppl 1):274S-280S.
19. Poehlman ET, Melby CL, Badylak SF, Calles J. Aerobic fitness
and resting energy expenditure in young adult males. Metabolism.
1989;38:85-90.
20. Tarantino G, Marra M, Contaldo F, Pasanisi F. Basal metabolic
rate in morbidly obese patients with non-alcoholic fatty liver dis-
ease. Clin Invest Med. 2008;31:E24-E9.
21. Kress J, Pohlman A, Alverdy J, Hall J. The impact of morbid obe-
sity on oxygen cost of breathing (VO(2RESP)) at rest. Am J
Respir Crit Care Med. 1999;160:883-886.
22. Ravussin E, Burnand B, Schutz Y, Je´quier E. Twenty-four-hour
energy expenditure and resting metabolic rate in obese, moderately
obese, and control subjects. Am J Clin Nutr. 1982;35:566-573.
23. Regensteiner JG, Sippel J, McFarling ET, Wolfel EE, Hiatt WR.
Effects of non-insulin-dependent diabetes on oxygen consump-
tion during treadmill exercise. Med Sci Sports Exerc. 1995;27:
661-667.
24. Huang KC, Kormas N, Steinbeck K, Loughnan G, Caterson ID.
Resting metabolic rate in severely obese diabetic and nondiabetic
subjects. Obesity. 2004;12:840-845.
25. Fisher P, Kleinerman JI. Total oxygen consumption and meta-
bolic rate of patients in diabetic acidosis. J Clin Investig. 1952;
31:126-130.
26. Horstmann P. The oxygen consumption in diabetes mellitus. Acta
Med Scand. 1951;139:326-330.
27. Snodgrass JJ, Leonard WR, Sorensen MV, Tarskaia LA, Mosher
MJ. The influence of basal metabolic rate on blood pressure among
indigenous Siberians. Am J Phys Anthropol. 2008;137:145-155.
28. Kunz I, Schorr U, Klaus S, Sharma AM. Resting metabolic rate
and substrate use in obesity hypertension. Hypertension. 2000;
36:26-32.
29. Rosenkrantz JA, Marshall C. Basal metabolic rate in hypertensive
vascular disease. Arch Intern Med. 1947;80:81-88.
30. Vaccarino V, Bremner JD. Stress response and the metabolic
syndrome. Cardiology. 2005;11(pt 2):1.
31. Licht CMM, Vreeburg SA, van Reedt Dortland AKB, et al.
Increased sympathetic and decreased parasympathetic activity
rather than changes in hypothalamic-pituitary-adrenal axis activ-
ity is associated with metabolic abnormalities. J Clin Endocrinol
Metab. 2010;95:2458-2466.
32. Lambert EA, Lambert GW. Stress and its role in sympathetic
nervous system activation in hypertension and the metabolic
syndrome. Curr Hypertens Rep. 2011;13:244-248.
33. Kyrou I, Tsigos C. Stress hormones: physiological stress and reg-
ulation of metabolism. Curr Opin Pharmacol. 2009;9:787-793.
34. Benson H. The Relaxation Response. New York, NY: Morrow;
1975.
35. Dusek JA, Benson H. Mind-body medicine: a model of the com-
parative clinical impact of the acute stress and relaxation
responses. Minn Med. 2009;92(5):47-50.
36. Storey KB, Storey JM. Metabolic rate depression and biochemical
adaptation in anaerobiosis, hibernation and estivation. Q Rev Biol.
1990;65:145-174.
37. Wolsko P. Use of mind-body medical therapies. J Gen Intern
Med. 2004;19:43-50.
38. Young JDE, Taylor E. Meditation as a voluntary hypometabolic
state of biological estivation. News Physiol Sci. 1998;13:
149-153.
39. Dillbeck MC, Orme-Johnson DW. Physiological differences
between transcendental meditation and rest. Am Psychol. 1987;
42:879-881.
40. Delmonte MM. Physiological responses during meditation and
rest. Biofeedback Self Regul. 1984;9:181-200.
41. Lehrer P, Schoicket S, Carrington P, Woolfork RL. Psychophy-
siological and cognitive responses to stressful stimuli in subjects
practicing progressive relaxation and clinically standardized med-
itation. Behav Res Ther. 1980;18:293-303.
42. Elson BD, Hauri P, Cunis D. Physiological changes in yoga med-
itation. Psychophysiology. 1977;14:52-57.
43. Benson H, Dryer T, Hartley LH. Decreased VO
2
consumption
during exercise with elicitation of the relaxation response.
J Human Stress. 1978;4(2):38-42.
44. Telles S, Patra S, Montesoo S, Naveen KV. Effect of yoga on
somatic indicators of stress in healthy volunteers. J Indian
Psychol. 2008;26:52-57.
45. Parshad O. Role of yoga in stress management. West Indian Med
J. 2004;53:191-194.
46. Sanghani S, Deavenport A, Herring P, Anderson SE, Medina E. A
pilot study: can a short-term complementary and alternative med-
icine intervention combat stress? Calif J Health Promot. 2008;
6(2):73-78.
47. Hartfiel N, Havenhand J, Khalsa SB, Clarke G, Krayer A. The
effectiveness of yoga for the improvement of well-being and resi-
lience to stress in the workplace. Scand J Work Environ Health.
2011;37:70-76.
48. Gopal A, Mondal S, Gandhi A, Arora S, Bhattacharjee J. Effect of
Integrated yoga practice on immune response in examination
stress: a preliminary study. Int J Yoga. 2011;4:26-32.
49. Malathi A, Damodaran A. Stress due to exams in medical stu-
dents: role of yoga. Indian J Physiol Pharmacol. 1999;43:
218-224.
50. DiNardo MM. Mind-body therapies in diabetes management.
Diabetes Spectr. 2009;22:30-34.
51. Gupta N, Khera S, Vempati RP, Sharma R, Bijlani RL. Effect of
yoga based lifestyle intervention on state and trait anxiety. Indian
J Physiol Pharmacol. 2006;50:41-47.
52. Agte VV, Chiplonkar SA. Sudarshan Kriya yoga for improving
antioxidant status and reducing anxiety in adults. Alter Comple-
ment Ther. 2008;14:96-100.
53. Javnbakht M, Hejazi Kenari R, Ghasemi M. Effects of yoga on
depression and anxiety of women. Complement Ther Clin Pract.
2009;15:102-104.
54. Vedamurthachar A, Janakiramaiah N, Hegde JM, et al. Antidepres-
sant efficacy and hormonal effects of Sudarshana Kriya Yoga
(SKY) in alcohol dependent individuals. JAffectDisord. 2006;
94:249-253.
55. Yoshihara K, Hiramoto T, Sudo N, Kuno C. Profile of mood states
and stress-related biochemical indices in long-term yoga practi-
tioners. Biopsychosoc Med. 2011;5(1):6.
Tyagi and Cohen 305
56. Wood C. Mood change and perceptions of vitality: a comparison
of the effects of relaxation, visualization and yoga. J R Soc Med.
1993;86:254-258.
57. Aljasir B, Bryson M, Al-Shehri B. Yoga practice for the manage-
ment of type II diabetes mellitus in adults: a systematic review.
Evid Based Complement Alternat Med. 2010;7:399-408.
58. Matsuda K, Ueno S, Oura N, et al. Yoga effects on moods
among women with infants. J Psychosom Obstet Gynaecol.
2007;28:77.
59. Carter J, Byrne G. A two year study of the use of yoga in a series
of pilot studies as an adjunct to ordinary psychiatric treatment in a
group of Vietnam War veterans suffering from post traumatic
stress disorder. http://www.therapywithyoga.com/Vivekananda.
pdf. Published 2004. Accessed November 27, 2012.
60. Rosenthal JZ, Grosswald S, Ross R, Rosenthal N. Effects of trans-
cendental meditation in veterans of Operation Enduring Freedom
and Operation Iraqi Freedom with posttraumatic stress disorder: a
pilot study. Mil Med. 2011;176:626-630.
61. Brooks JS, Scarano T. Transcendental meditation in the treatment
of post-Vietnam adjustment. J Couns Dev. 1985;64:212-215.
62. Telles S, Naveen K, Dash M. Yoga reduces symptoms of distress
in tsunami survivors in the Andaman Islands. Evid Based Comple-
ment Alternat Med. 2007;4:503-510.
63. Descilo T, Vedamurtachar A, Gerbarg PL, et al. Effects of a yoga
breath intervention alone and in combination with an exposure
therapy for post-traumatic stress disorder and depression in survi-
vors of the 2004 South-East Asia tsunami. Acta Psychiatr Scand.
2010;121:289-300.
64. Gerbarg PL, Brown RP. Yoga: a breath of relief for Hurricane
Katrina refugees. Curr Psychiatr. 2005;4(10):55-67.
65. Telles S, Singh N, Joshi M, Balkrishna A. Post traumatic stress
symptoms and heart rate variability in Bihar flood survivors follow-
ing yoga: a randomized controlled study. BMCPsychiatry. 2010;10:
18.
66. Li AW, Goldsmith CAW. The effects of yoga on anxiety and
stress. Altern Med Rev. 2012;17:21-35.
67. Chong CS, Tsunaka M, Tsang HW, Chan EP, Cheung WM.
Effects of yoga on stress management in healthy adults: a sys-
tematic review. Altern Ther Health Med. 2011;17:32-38.
68. Bharshankar JR, Bharshankar RN, Deshpande VN, Kaore SB,
Gosavi GB. Effect of yoga on cardiovascular system in subjects
above 40 years. Indian J Physiol Pharmacol. 2003;47:202-206.
69. Gopal KS, Bhatnagar OP, Subramanian N, Nishith SD. Effect of
yogasanas and pranayamas on blood pressure, pulse rate and some
respiratory functions. Indian J Physiol Pharmacol. 1973;17:
273-276.
70. Chaya M, Kurpad A, Nagendra H, Nagarathna R. The effect of
long term combined yoga practice on the basal metabolic rate
of healthy adults. BMC Complement Altern Med. 2006;6(1):28.
71. Chaya M, Nagendra H. Long-term effect of yogic practices on
diurnal metabolic rates of healthy subjects. Int J Yoga. 2008;
1(1):27-32.
72. Balk JL. Yoga for weight loss. Altern Med Alert. 2011;14(5):49-53.
73. Seo DY, Lee S, Figueroa A, et al. Yoga training improves
metabolic parameters in obese boys. Korean J Physiol Pharma-
col. 2012;16:175-180.
74. Vyas R, Raval KV, Dikshit N. Effect of Raja yoga meditation on
the lipid profile of post-menopausal women. Indian J Physiol
Pharmacol. 2008;52:420-424.
75. Telles S, Visweswaraiah NK, Balkrishna A. Serum leptin, choles-
terol and blood glucose levels in diabetics following a yoga and
diet change program. Med Sci Monit. 2010;16(3):LE4-LE5.
76. Pal A, Srivastava N, Tiwari S, et al. Effect of yogic practices on
lipid profile and body fat composition in patients of coronary
artery disease. Complement Ther Med. 2011;19:122-127.
77. Sahay BK. Role of yoga in diabetes. J Assoc Physicians India.
2007;55:121-126.
78. Mohta N, Agrawal RP, Kochar DK, Kothari RP, Sharma A. Influ-
ence of yogic treatment on quality of life outcomes, glycemic con-
trol, and risk factors in diabetes mellitus: randomized controlled
trial. Explore (NY). 2009;5(3):147.
79. Bhavanani AB, Sanjay ZZ, Madanmohan. Immediate effect of
sukha pranayama on cardiovascular variables in patients of hyper-
tension. Int J Yoga Therap. 2011(21):73-76.
80. Okonta NR. Does yoga therapy reduce blood pressure in patients
with hypertension? An integrative review. Holist Nurs Pract.
2012;26:137-141.
81. Bhavanani AB, Madanmohan Sanjay Z. Immediate effect of
chandra nadi pranayama (left unilateral forced nostril breathing)
on cardiovascular parameters in hypertensive patients. Int J Yoga.
2012;5:108-111.
82. Cohen BE, Chang AA, Grady D, Kanaya AM. Restorative yoga in
adults with metabolic syndrome: a randomized, controlled pilot
trial. Metab Syndr Relat Disord. 2008;6:223-229.
83. Khatri D, Mathur KC, Gahlot S, Jain S, Agrawal RP. Effects of
yoga and meditation on clinical and biochemical parameters of
metabolic syndrome. Diabetes Res Clin Pract. 2007;78(3):e9-e10.
84. Lee JA, Kim JW, Kim DY. Effects of yoga exercise on serum
adiponectin and metabolic syndrome factors in obese postmeno-
pausal women. Menopause. 2012;19:296-301.
85. Rao S. The metabolic cost of head-stand posture. J Appl Physiol.
1962;17:117-118.
86. Rao S. Oxygen consumption during yoga-type breathing at alti-
tudes of 520 m and 3,800 m. Indian J Med Res. 1968;56:701-705.
87. Karambelkar PV, Deshapande RR, Bhole MV. Some respiratory
studies in respect of kapalbhati and voluntary hyperventilation.
Yoga Mimamsa. 1982;21(1&2):54-58.
88. Karambelkar PV, Deshapande RR, Bhole MV. Some respiratory
studies on bhastrika pranayama with internal and external reten-
tion. Yoga Mimamsa. 1982;21(3&4):14-20.
89. Karambelkar PV, Bhole MV. Respiratory studies during kapalb-
hati for 1, 2, 3 and 5 minutes. Yoga Mimamsa. 1988;27(1&2):
69-74.
90. Karambelkar PV, Deshapande RR, Bhole MV. Some respiartory
studies of ujjayi and bhastrika pranayama with bahya kumbhak.
Yoga Mimamsa. 1983;22(3&4):7-12.
91. Karambelkar PV, Deshpande RR, Bhole MV. Oxygen consump-
tion during ujjayi pranayama. Yoga Mimamsa. 1983;21(3&4):
7-13.
92. Telles S, Desiraju T. Oxygen consumption during pranayamic
type of very slow-rate breathing. Indian J Med Res. 1991;94:
357-363.
306 Journal of Evidence-Based Complementary & Alternative Medicine 18(4)
93. Telles S, Nagarathna R, Nagendra HR. Physiological measures
of right nostril breathing. J Altern Complement Med. 1996;2:
479-484.
94. Prasad KVV, Venkata Ramana Y, Raju PS, et al. Energy cost
and physiological efficiency in male yoga practitioners. J Exerc
Physiol Online. 2001;4(3):38-44.
95. Ray US, Pathak A, Tomer OS. Hatha yoga practices: energy
expenditure, respiratory changes and intensity of exercise. Evid
Based Complement Alternat Med. 2011;2011:241-294.
96. Telles S, Nagarathna R, Nagendra HR. Breathing through a
particular nostril can alter metabolism and autonomic activities.
Indian J Physiol Pharmacol. 1994;38:133-137.
97. Anand B, Chhina G, Singh B. Studies on Shri Ramanand Yogi
during his stay in an air-tight box. Indian J Med Res. 1961;49:
82-89.
98. Karambelkar PV, Vinekar SL, Bhole MV. Studies on human
subjects staying on an air-tight pit. Indian J Med Res. 1968;56:
1282-1288.
99. Craig Heller H, Elsner R, Rao N. Voluntary hypometabolism in
an Indian yogi. J Therm Biol. 1987;12:171-173.
100. Vempati R, Telles S. Yoga based guided relaxation reduces sym-
pathetic activity in subjects based on baseline levels. Psychol
Rep. 2002;90:487-494.
101. Vempati R, Telles S. Yoga based isometric relaxation versus
supine rest: a study of oxygen consumption, breath rate and vol-
ume and autonomic measures. J Indian Psychol. 1999;17(2):
46-52.
102. Rai L, Ram K, Kant U, Madan SK, Sharma SK. Energy expen-
diture and ventilatory responses during Siddhasana: a yogic
seated posture. Indian J Physiol Pharmacol. 1994;38:29-33.
103. Rai L, Ram K. Energy expenditure and ventilatory responses
during Virasana: a yogic standing posture. Indian J Physiol
Pharmacol. 1993;37:45-50.
104. Sinha B, Ray U, Pathak A, Selvamurthy W. Energy cost and
cardiorespiratory changes during the practice of Surya Namas-
kar. Indian J Physiol Pharmacol. 2004;48:184-190.
105. Telles S, Reddy S, Nagendra H. Oxygen consumption and
respiration following two yoga relaxation techniques. Appl
Psychophysiol Biofeedback. 2000;25:221-227.
106. Sarang PS, Telles S. Oxygen consumption and respiration during
and after two yoga relaxation techniques. Appl Psychophysiol
Biofeedback. 2006;31:143-153.
107. Salgar DC, Bisen VS, Jinturkar MJ. Effect of padmasana. A
yogic exercise on muscular efficiency. Indian J Med Res.
1975;63:768-772.
108. Bhatnagar OP, Ganguly AK, Anantharaman V. Influence of
yoga training on thermoregulation. Indian J Med Res. 1978;67:
844-847.
109. Joseph S, Sridharan K, Patil SKB. Study of some physiological
and biochemical parameters in subjects undergoing yogic train-
ing. Indian J Med Res. 1981;74:120-124.
110. Raju PS, Kumar KA, Reddy SS, et al. Effect of yoga on exercise
tolerance in normal healthy volunteers. Indian J Physiol
Pharmacol. 1986;30:121-132.
111. Raju PS, Prasad KVV, Venkata RY, Murthy KJ, Reddy MV.
Influence of intensive yoga training on physiological changes
in 6 adult women: a case report. J Altern Complement Med.
1997;3:291-295.
112. Raju PS, Madhavi S, Prasad KV, et al. Comparison of effects of
yoga & physical exercise in athletes. Indian J Med Res. 1994:
100:81-86.
113. Nayar HS, Mathur RM, Sampath Kumar R. Effects of yogic
exercises on human physical efficiency. Indian J Med Res.
1975;63:1369-1376.
114. Selvamurthy W, Ray US, Hegde KS, Sharma RP. Physiological
responses to cold (10C) in men after six months’ practice of
yoga exercises. Int J Biometeorol. 1988;32:188-193.
115. Ray US, Sinha B, Tomer OS, Pathak A, Dasgupta T, Selva-
murthy W. Aerobic capacity & perceived exertion after practice
of Hatha yogic exercises. Indian J Med Res. 2001;114:215-221.
116. Balasubramanian B, Pansare MS. Effect of yoga on aerobic and
anaerobic power of muscles. Indian J Physiol Pharmacol. 1991;
35:281-282.
117. Telles S, Nagarathna R, Nagendra HR. Autonomic changes
during ‘‘OM’’ meditation. Indian J Physiol Pharmacol. 1995;
39:418-420.
118. Miles WR, Behanan KT. A metabolic study of three unusual
learned breathing patterns practiced in the cult of yoga. Am J
Psychol. 1934;109:74-75.
119. Miles W. Oxygen consumption during three yoga-type breathing
patterns. J Appl Physiol. 1964;19:75-82.
120. Wallace RK. Physiological effects of transcendental meditation.
Science. 1970;167:1751-1754.
121. Wallace RK, Benson H, Wilson AF. A wakeful hypometabolic
physiologic state. Am J Psychol. 1971;221:795-799.
122. Benson H, Steinert RF, Greenwood MM, Klemchuk HM, Peter-
son NH. Continuous measurement of O
2
consumption and CO
2
elimination during a wakeful hypometabolic state. J Human
Stress. 1975;1:37-44.
123. Warrenburg S, Pagano RR, Woods M, Hlastala M. A compari-
son of somatic relaxation and EEG activity in classical progres-
sive relaxation and transcendental meditation. J Behav Med.
1980;3:73-93.
124. Kesterson J, Clinch NF. Metabolic rate, respiratory exchange
ratio, and apneas during meditation. Am J Physiol Regul Integr
Comp Physiol. 1989;256:R632-R638.
125. Blank SE. Physiological responses to Iyengar yoga performed by
trained practitioners. J Exerc Physiol Online. 2006;9(1):7-23.
126. Hagins M, Moore W, Rundle A. Does practicing hatha yoga sat-
isfy recommendations for intensity of physical activity which
improves and maintains health and cardiovascular fitness? BMC
Complement Altern Med. 2007;7:40.
127. Carroll J, Blansit A, Otto R, et al. The metabolic requirements of
vinyasa yoga. Med Sci Sports Exerc. 2003;35(5):S155.
128. Tran MD, Holly RG, Lashbrook J, Amsterdam EA. Effects of
hatha yoga practice on the health-related aspects of physical
fitness. Prev Cardiol. 2001;4:165-170.
129. Tracy BL, Hart CE. Bikram yoga training and physical fitness in
healthy young adults. J Strength Cond Res. 2013;27:822-830.
130. Pullen PR, Nagamia SH, Mehta PK, et al. Effects of yoga on
inflammation and exercise capacity in patients with chronic
heart failure. J Card Fail. 2008;14:407-413.
Tyagi and Cohen 307
131. Clay CC, Lloyd LK, Walker JL, Sharp KR, Pankey RB. The meta-
bolic cost of hatha yoga. J Strength Cond Res. 2005;19:604-610.
132. DiCarlo L, Sparling P, Hinson B, Snow T, Rosskopf L. Cardio-
vascular, metabolic, and perceptual responses to hatha yoga
standing poses. Med Exerc Nutr Health. 1995;4:107-112.
133. Bowman AJ, Clayton RH, Murray A, Reed JW, Subhan MM,
Ford GA. Effects of aerobic exercise training and yoga on the
baroreflex in healthy elderly persons. Eur J Clin Invest. 1997;
27:443-449.
134. Fenwick PBC, Donaldson S, Gillis L. Metabolic and EEG
changes during transcendental meditation: an explanation. Biol
Psychiatry. 1977;5:101-118.
135. Ramos-Jime´ nez A, Herna´ ndez-Torres RP, Wall-Medrano A,
Mun
˜oz-Daw MDJ, Torres-Dura´ n PV, Jua´rez-Oropeza MA.
Cardiovascular and metabolic effects of intensive Hatha yoga
training in middle-aged and older women from northern Mexico.
Int J Yoga. 2009;2(2):49-54.
136. Throll DA. Transcendental meditation and progressive relaxation:
their physiological effects. JClinPsychol. 1982;38:522-530.
137. Buranruk O, La Grow S, Ladawan S, Makarawate P, Suwanich
T, Leelayuwat N. Thai yoga as an appropriate alternative phys-
ical activity for older adults. J Complement Integr Med. 2010;
7(1). doi:10.2202/1553-3840.1290.
138. Danucalov MA, Simo
˜es RS, Kozasa EH, Leite JR. Cardiore-
spiratory and metabolic changes during yoga sessions: The
effects of respiratory exercises and meditation practices. Appl
Psychophysiol Biofeedback. 2008;33(2):77-81.
139. Miyamura M, Nishimura K, Ishida K, Katayama K, Shimaoka
M, Hiruta S. Is man able to breathe once a minute for an hour?
The effect of yoga respiration on blood gases. Jpn J Physiol.
2002;52:313-316.
140. Frostell C, Pande JN, Hedenstierna G. Effects of high-frequency
breathing on pulmonary ventilation and gas exchange. J Appl
Physiol. 1983;55:1854-1861.
141. Vivekananda R. Practical Yoga Psychology. Munger, India:
Yoga Publications Trust; 2005.
142. Ramos-Jime´ nez A, Herna´ndez-Torres R, Wall-Medrano A.
Hatha yoga program determinants on cardiovascular health in
physically active adult women. J Yoga Phys Ther. 2011;
1(103). doi:10.4172/2157-7595.1000103.
143. Energy and Protein Requirements: Report of a Joint FAO/WHO/
UNU Expert Consultation. Geneva, Switzerland: World Health
Organization; 1985.
144. Poehlman ET, Melby CL, Badylak SF. Resting metabolic rate
and postprandial thermogenesis in highly trained and untrained
males. Am J Clin Nutr. 1988;47:793-798.