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Does practicing hatha yoga satisfy recommendations for intensity of physical activity which improves and maintains health and cardiovascular fitness?

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Little is known about the metabolic and heart rate responses to a typical hatha yoga session. The purposes of this study were 1) to determine whether a typical yoga practice using various postures meets the current recommendations for levels of physical activity required to improve and maintain health and cardiovascular fitness; 2) to determine the reliability of metabolic costs of yoga across sessions; 3) to compare the metabolic costs of yoga practice to those of treadmill walking. In this observational study, 20 intermediate-to-advanced level yoga practitioners, age 31.4 +/- 8.3 years, performed an exercise routine inside a human respiratory chamber (indirect calorimeter) while wearing heart rate monitors. The exercise routine consisted of 30 minutes of sitting, 56 minutes of beginner-level hatha yoga administered by video, and 10 minutes of treadmill walking at 3.2 and 4.8 kph each. Measures were mean oxygen consumption (VO2), heart rate (HR), percentage predicted maximal heart rate (%MHR), metabolic equivalents (METs), and energy expenditure (kcal). Seven subjects repeated the protocol so that measurement reliability could be established. Mean values across the entire yoga session for VO2, HR, %MHR, METs, and energy/min were 0.6 L/kg/min; 93.2 beats/min; 49.4%; 2.5; and 3.2 kcal/min; respectively. Results of the ICCs (2,1) for mean values across the entire yoga session for kcal, METs, and %MHR were 0.979 and 0.973, and 0.865, respectively. Metabolic costs of yoga averaged across the entire session represent low levels of physical activity, are similar to walking on a treadmill at 3.2 kph, and do not meet recommendations for levels of physical activity for improving or maintaining health or cardiovascular fitness. Yoga practice incorporating sun salutation postures exceeding the minimum bout of 10 minutes may contribute some portion of sufficiently intense physical activity to improve cardio-respiratory fitness in unfit or sedentary individuals. The measurement of energy expenditure across yoga sessions is highly reliable.
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BioMed Central
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BMC Complementary and
Alternative Medicine
Open Access
Research article
Does practicing hatha yoga satisfy recommendations for intensity of
physical activity which improves and maintains health and
cardiovascular fitness?
Marshall Hagins*
†1
, Wendy Moore
†2
and Andrew Rundle
†2
Address:
1
Division of Physical Therapy, Long Island University, One University Plaza, Brooklyn, NY 11201, USA and
2
Mailman School of Public
Health, Columbia University, 622 W. 168th St. New York, NY 10032, USA
Email: Marshall Hagins* - mhagins@liu.edu; Wendy Moore - mcdowell_wendy@hotmail.com; Andrew Rundle - ag3r@columbia.edu
* Corresponding author †Equal contributors
Abstract
Background: Little is known about the metabolic and heart rate responses to a typical hatha yoga
session. The purposes of this study were 1) to determine whether a typical yoga practice using
various postures meets the current recommendations for levels of physical activity required to
improve and maintain health and cardiovascular fitness; 2) to determine the reliability of metabolic
costs of yoga across sessions; 3) to compare the metabolic costs of yoga practice to those of
treadmill walking.
Methods: In this observational study, 20 intermediate-to-advanced level yoga practitioners, age
31.4 ± 8.3 years, performed an exercise routine inside a human respiratory chamber (indirect
calorimeter) while wearing heart rate monitors. The exercise routine consisted of 30 minutes of
sitting, 56 minutes of beginner-level hatha yoga administered by video, and 10 minutes of treadmill
walking at 3.2 and 4.8 kph each. Measures were mean oxygen consumption (VO
2
), heart rate (HR),
percentage predicted maximal heart rate (%MHR), metabolic equivalents (METs), and energy
expenditure (kcal). Seven subjects repeated the protocol so that measurement reliability could be
established.
Results: Mean values across the entire yoga session for VO
2
, HR, %MHR, METs, and energy/min
were 0.6 L/kg/min; 93.2 beats/min; 49.4%; 2.5; and 3.2 kcal/min; respectively. Results of the ICCs
(2,1) for mean values across the entire yoga session for kcal, METs, and %MHR were 0.979 and
0.973, and 0.865, respectively.
Conclusion: Metabolic costs of yoga averaged across the entire session represent low levels of
physical activity, are similar to walking on a treadmill at 3.2 kph, and do not meet recommendations
for levels of physical activity for improving or maintaining health or cardiovascular fitness. Yoga
practice incorporating sun salutation postures exceeding the minimum bout of 10 minutes may
contribute some portion of sufficiently intense physical activity to improve cardio-respiratory
fitness in unfit or sedentary individuals. The measurement of energy expenditure across yoga
sessions is highly reliable.
Published: 30 November 2007
BMC Complementary and Alternative Medicine 2007, 7:40 doi:10.1186/1472-6882-7-40
Received: 13 June 2007
Accepted: 30 November 2007
This article is available from: http://www.biomedcentral.com/1472-6882/7/40
© 2007 Hagins et al; licensee BioMed Central Ltd.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0
),
which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
BMC Complementary and Alternative Medicine 2007, 7:40 http://www.biomedcentral.com/1472-6882/7/40
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Background
Physical activity conveys multiple well established health
benefits including decreased rates of coronary artery dis-
ease [1-3], hypertension [4,5], non-insulin dependent
diabetes mellitus [6], osteoporosis [7], colon cancer [8],
anxiety and depression [9,10], as well as decreased risk of
overall mortality [1]. Despite these clear benefits less than
half of U.S. adults meet the current recommendations for
physical activity [11].
The most recent recommendations from the American
College of Sports Medicine (ACSM) and the American
Heart Association (AHA) [12] suggest that to promote and
maintain health all healthy adults aged 18–65 years old
need moderate-intensity aerobic (endurance) activity for a
minimum of 30 minutes on five days each week or vigor-
ous-intensity activity for a minimum of 20 minutes on
three days each week. These recommendations further
suggest that combinations of moderate and vigorous exer-
cise can be used to meet the requirements and that bouts
of moderate-intensity exercise lasting a minimum of 10
minutes can be accumulated to achieve the 30 minute
minimum. Recommendations for developing and main-
taining cardiovascular fitness from the ACSM Position
Stand recommend that exercise achieve 55–90% of the
maximal heart rate, be performed 3–5 days per week, and
last 20–60 minutes (continuous or intermittent) [13].
Yoga is an alternative form of physical activity which may
assist in achieving recommended levels of physical activ-
ity for some individuals. Yoga is increasing in popularity
[14-16] with a recent report suggesting that 15 million
Americans have practiced yoga at least once in their life-
time [17]. Yoga classes are now offered at 75% of all U.S.
health clubs [18], as well as at yoga studios and in private
homes. Yoga may be attractive as an alternative to tradi-
tional aerobic and strength training programs because it
requires little space, virtually no equipment, has limited
harmful side effects [14,16,19,20] and, with its focus on
relaxation, body awareness, and meditation provides a
qualitatively different exercise experience which may be
perceived as less strenuous and more pleasurable. Given
these characteristics, yoga satisfies many of the conditions
which have been shown to be strongly related to partici-
pation in physical activity, such as low perceived barrier to
participation [21], being enjoyable [21], and having a
low-to-moderate intensity [22].
Although yoga has received a considerable amount of
study to date demonstrating significant cardio-respiratory
[23-42], musculoskeletal [43,44] and metabolic health
benefits [42], the degree to which the physical activity
component of yoga may have contributed to these bene-
fits has received virtually no attention. Surveying the Eng-
lish speaking literature available via Pubmed and
CINAHL revealed eight studies examining the metabolic
costs of yoga. Of these studies [45-52], only one [51]
examined the variety of postures seen in a typical yoga
class (standing, sitting, and lying). Additionally, all previ-
ous studies used measurement techniques that physically
encumber the subject by requiring masks or mouthpieces
to measure oxygen consumption. Such techniques may
alter the performance of the yoga activities and therefore
provide invalid estimates of metabolic costs.
Therefore, the purposes of this study were: 1) to determine
whether an approximately one hour yoga session incorpo-
rating a variety of postures meets the current recommen-
dations for physical activity sufficient to improve and
maintain health [12] and cardiovascular fitness [13] as
measured within a respiratory chamber (indirect calorim-
eter); 2) to determine the reliability with which the meta-
bolic costs of yoga can be measured; 3) to compare the
metabolic costs of yoga practice to the metabolic costs of
steady state treadmill walking at two speeds (3.2 and 4.8
kph).
Methods
Subjects
Subjects were recruited via fliers posted at various yoga
studios around New York, NY, USA, and on the Columbia
University Health Sciences campus. Each participant was
administered an eligibility questionnaire by telephone
prior to enrolment. Exclusion criteria included: a) age <
18 years; b) < 1 year experience doing yoga; b) negative
response to the question "are you comfortable doing Sun
Salutation and basic yoga standing poses such as Triangle,
Warriors I and II, and Tree?;" c) negative response to the
question "are you able to do inversions (headstand,
shoulder stand) with or without a wall?"; d) presence of
any physical conditions or limitations that would prevent
the individual from performing the tasks involved in the
study. These exclusion criteria ensured that the partici-
pants would be able to engage in the yoga routine safely
and that the measurements taken would not be influ-
enced by inexperience.
Measurement Instruments
The study took place at the Obesity Research Center at St.
Luke's-Roosevelt Hospital, New York, N.Y., USA. After
providing informed consent, each participant was outfit-
ted with one Actiheart™ activity and heart rate logger
(Mini-Mitter, OR, USA). The Actiheart™ is a small, light-
weight device that was affixed to each participant's chest
using standard EKG pads. It collected continuous heart
rate (HR) data and produced data points at 1-minute
intervals, reflecting the average heart rate for each minute.
Each participant performed all activities inside the respira-
tory chamber. The performance characteristics of the res-
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piratory chamber have been described elsewhere [53,54].
Briefly, the system is an air-tight, temperature-controlled
room in which rates of oxygen consumption (VO
2
) and
carbon dioxide production (VCO
2
) are calculated as the
difference between the composition of entering and exit-
ing air. Analysis uses magnetopneumatic oxygen (Magnos
4G) and carbon dioxide (Magnos 3G) analyzers (Hart-
mann & Braun, Frankfurt, Germany), and the data is dis-
played and stored by the on-line computer system. The
respiratory chamber provided the average values for VO
2
,
VCO
2
, and energy expenditure (kcal/min) every two min-
utes. Energy expenditure was calculated via the respiratory
chamber software using a modified Weir equation: EE =
(3.94 × VO
2
) + (1.1 × (VCO
2
) [55].
Resting metabolic rate (RMR) for each participant was cal-
culated by taking the mean energy expenditure during the
last 20 minutes of the initial resting period. Each subse-
quent value for energy was divided by the RMR to deter-
mine metabolic equivalents (METs). To obtain the
predicted maximum heart rate for each individual, the fol-
lowing formula was used: 208 – (0.7 × age) [56]. Heart
rate data was multiplied by 100 and divided by the pre-
dicted maximum heart rate to determine the percentage of
maximum predicted heart rate (%MHR) achieved by each
individual for each 1-minute interval.
Procedures
Subjects initially performed a 30 minute resting period
during which they were seated and motionless except for
the movements associated with reading (e.g., turning
pages). Subjects then began a 56-minute beginner Ash-
tanga yoga DVD [57]. The yoga session began with 28
minutes of sun salutation poses (a standard series of mov-
ing poses found in many styles of yoga), followed by
approximately 20 minutes of standing poses, and lastly,
approximately 8 minutes of sitting and lying poses (relax-
ation). Table 1 describes the postures and time for each
portion of the yoga session. For additional details see the
commercially available "Ashtanga Yoga Beginner's Prac-
tice DVD [57]."
After completing the yoga practice, subjects walked on a
treadmill at two different speeds in the following order:
3.2 kph (2 mph) and 4.8 kph (3 mph) for 10 minutes
each. To determine across-session reliability, a conven-
ience sample of seven participants returned between one
week and one month later to perform an identical test
protocol.
The first four minutes of HR and respiratory chamber data
for each activity was discarded to allow each participant
time to achieve a steady state of energy demand. There-
fore, the data used for analysis included the final 20 min-
utes of the resting period, the final 52 minutes of the yoga
session, and the final 6 minutes of each treadmill period.
Statistical Analyses
SAS version 9.1 (SAS Institute Inc., Cary, NC, USA.) was
used for all statistical analysis. Description of the means
and standard deviations for all variables across the entire
time periods of the resting, yoga, and treadmill activities
were determined. Data from the seven subjects who
repeated the measurement session were tested for reliabil-
ity using Intra Class Correlation Coefficients (ICC) (2,1).
Two separate one-sample t-tests were used to determine
whether the mean METs across the entire yoga session and
across the sun salutation portion of the yoga practice dif-
fered from the minimum values for METs (3.0) recom-
mended by ACSM and AHA [12]. Additionally, two
separate one-sample t-tests were used to determine
whether the mean %MHR across the entire yoga session
and across the sun salutation portion of the yoga practice
differed from the minimum values of 55% MHR recom-
mended by the ACSM Position Stand [13].
Table 1: Description of yoga practice
Surya Namaskar (Sun Salutation)
28 minutes
Pose Name
Stand at Attention Samasthiti
Hands above head Ekam
Forward Bend Uttanasana
Forward Bend/Head up Trini
Down-dog Adhomukha Svanasana
Four-legged staff pose Chaturanga Dandasana
Up-dog Urdhvamukha Svanasana
Chair Utkatasana
Warrior I Virabhadrasana
Standing Poses
20 minutes
Hands-to-feet Padahastasana
Triangle Trikonasana
Revolved triangle Parivrtta Trikonasana
Side angle stretch Parivrtta Parsvakonasana
Chest stretch Parsvottanasana
Sitting/Lying Poses
8 minutes
Lotus Padmasana
Corpse Savasana
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Three separate ANOVAs were used to compare the mean
rate of energy expenditure (kcal), METs, and %MHR
across the following activities: 1) rest; 2) entire yoga ses-
sion; 3) treadmill walking at 3.2 kph; 4) treadmill walking
at 4.8 kph. The sun salutation portion of the yoga session
was not included in the first set of ANOVAs as the sun sal-
utation portion and the entire yoga session are correlated
and as such an analysis would have violated the assump-
tions of the ANOVA. Consequently, in order to compare
the identical variables (kcal, METs, and %MHR) during
the sun salutation portion of the yoga session a second set
of three separate ANOVAs were performed on 1) rest; 2)
sun salutation portion of the yoga session; 3) treadmill
walking at 3.2 kph; 4) treadmill walking at 4.8 kph.
Because the order of the activities was not randomized
and the increase in metabolism from the yoga activity may
have influenced the metabolic rate during the ensuing
treadmill activity, post hoc testing was performed to deter-
mine if the METs and %MHR during the final three min-
utes of the yoga program (during supine relaxation) had
returned to values equal to those of the resting state.
Results
Twenty participants were recruited (18 female and 2
male). Results of the t-tests and ANOVAs were not differ-
ent whether the two men were excluded from analysis or
not, and therefore we report values from all 20 partici-
pants. The mean demographic values for the participants
were: age 31.4, (± 8.3) years, height 165.2 (± 7.9) cm,
weight 64.3 (± 9.0) kg, and BMI 23.58 (± 3.03). Means
and standard deviations of HR, calories, VO
2
, METS, and
%MHR relative to the entire yoga session, sun salutation
postures, non-sun salutation postures, sitting/lying pos-
tures, and treadmill walking are described in Table 2. In a
single subject, two values of energy expenditure during
the final two minutes of the yoga session (during supine
resting) were identified as outliers due to technical error
(METs increased by a factor of ~5 between minutes 50 and
51 during supine resting (1.31 to 5.06 METs)). The out-
liers were replaced using the subject's value for the minute
immediately prior to their occurrence (e.g., value at
minute 50:1.31 METs). Figures 1 and 2 graphically
describe the mean and SD of METs and %MHR, respec-
tively, for each minute during the entire yoga session.
Results of the ICCs (2,1) (n = 7) for mean values across
the entire yoga session for metabolic cost (kcal), METs,
and %MHR were 0.979, 0.973, and 0.865, respectively.
The ICC value for %MHR only was based on 5 subjects,
rather than 7, due to technical errors arising during data
collection.
Results of the one-sample t-tests comparing mean METs
and %MHR to recommended values are presented in
Table 3. The mean METs across the entire yoga session
were significantly less than the moderate level of physical
activity reference value of 3.0 METs recommended for
improving and maintaining health by the ACSM and AHA
[12]. However, the mean METS during the sun salutation
portion of the yoga session was not significantly different
from the reference vale of 3.0 METs [12]. The mean
%MHR during the entire yoga session was significantly
less than the 55% of MHR described as a minimum
threshold by the ACSM Position Stand [13] to achieve car-
dio-respiratory fitness. However, the mean %MHR during
the sun salutation portion of the yoga session (24 min-
utes) was not significantly different from the 55% MHR
recommended by the ACSM Position Stand [13].
Results of the three separate repeated measures ANOVAs
examining mean rate of energy (kcal), METs, and %MHR
across resting, the entire yoga session and two treadmill
speeds found that all three variables differed significantly
across the activities (p < 0.0001). All pair wise compari-
sons of the three variables were significantly different
across all activities, with the exception that all three varia-
bles were not significantly different when comparing the
entire yoga session to walking on a treadmill at 3.2 kph.
Results of the second set of three separate repeated meas-
ures ANOVAs (kcal, METs, and %MHR) in which the
entire yoga session activity was replaced with the sun sal-
utation activity found that all three variables differed sig-
Table 2: Means and standard deviations for energy and heart rate parameters across all activities
Task Task Heart Rate (bpm)* Energy (kcal/min) VO
2
(l/kg/min) METs %MHR*
Resting (20 mins) 71.0 (13.0) 1.2 (0.5) 0.3 (0.1) 1.0 (0.3) 38.2 (7.0)
Yoga Across entire Session (52 mins) 93.2 (25.9) 3.2 (1.1) 0.6 (0.2) 2.5 (0.8) 49.4 (12.2)
Sun Salutation (24 mins) 103.5 (25.2) 3.73 (1.01) 0.76 (0.21) 2.9 (0.77) 54.8 (11.8)
Non-Sun Salutation Standing Poses (20 mins) 89.7 (23.9) 3.01 (0.810 0.61 (0.16) 2.34 (0.60) 47.3 (10.4)
Sitting/Lying poses (8 mins) 72.5 (16.1) 1.93 (0.78) 0.40 (0.18) 1.5 (0.58) 38.7 (8.7)
Treadmill 3.2 kph/Level (6 mins) 97.8 (21.2) 3.1 (0.6) 0.7(0.1) 2.5(0.4) 50.7(8.0)
4.8 kph/Level (6 mins) 110.3 (23.1) 4.2 (0.4) 0.9 (0.1) 3.3 (0.4) 58.1 (10.7)
*All subjects (n = 20) performed all activities. However, due to missing values, secondary to technical issues, data from only 18 subjects were
included in %MHR calculations. MHR = Maximum predicted heart rate; METs = Metabolic equivalents;
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nificantly across the activities (p < 0.0001). All pair wise
comparisons of the three variables were significantly dif-
ferent across all activities; with the exception that %MHR
was not significantly different when comparing the sun
salutations postures to walking on a treadmill at 4.8 kph.
By the end of the yoga session (during Savasana, resting
supine posture) the mean METs had returned to 1, sug-
gesting that the subjects had returned to the metabolic
equivalent of a resting state. Post hoc statistical testing
found that METs and %MHR during the final three min-
utes of the yoga session were not significantly different
from mean values found during the initial rest period.
Discussion
The current study found that the metabolic costs of yoga
averaged across the entire session represent low levels of
physical activity [58]. Mean values for kcal/min (3.2, ±
1.1), METs (2.5, ± 0.8), and %MHR (49.4, ± 12.2) were
not significantly different from mean values during walk-
ing at 3.2 kph on a level treadmill. This level of physical
activity was significantly lower than the recommenda-
tions for "moderate" levels of physical activity recom-
mended by ACSM and AHA (3.0 METs) [12] and as
recommended by the ACSM Position stand (55%MHR)
[13].
Only four studies exist that may provide some compari-
son to the current study as they examined a variety of yoga
postures which best represent a typical yoga class, similar
to the current study [49-52]. Of these, one [52] provided
insufficient description of the postures for valid compari-
son stating only that there were "six yoga positions." The
remaining studies provided data on a series of well-
described standing postures, however, the only study for
comparison which included standing, sitting, and lying
postures as in the current study is that of Clay et al.[51].
Clay et al.[51] studied a much shorter session (30 mins),
a different selection of postures, younger subjects (differ-
ence of means: approximately 8 years), and used an indi-
rect calorimeter requiring collection of gases from a mask
or mouthpiece. These differences in methodology may
explain why Clay et al.[51] found the mean caloric
expenditure across the entire yoga session to be approxi-
mately 30% less than that found in the current study (2.23
vs 3.2 kcal/min).
Only two studies have provided %MHR during yoga for
comparison to the current study [51,52]. The mean
%MHR of 49.4% seen in this study appeared to be similar
to that Clay et al.[51] which yielded a mean %MHR of
56.9%, and considerably less than that of Carroll et al. at
77%. However, the study by Carroll et al. represents
standing postures only in a Vinyasa style (flowing move-
ment) measured for 15 minutes, and therefore is unlikely
to represent the mean %MHR across a typical yoga ses-
sion.
It is important to recognize that the mean values across
the entire yoga session described above represent a com-
bination of standing, sitting, and lying postures and that
Mean %MHR and standard deviation per minute during the yoga session (n = 18)Figure 2
Mean %MHR and standard deviation per minute dur-
ing the yoga session (n = 18). Data from the first four
minutes of the 56 minute yoga practice are not displayed.
The postures used within each section of the yoga practice
(see Table 1) varied in sequence and timing. Minutes 1–24
were sun salutation postures with postures changing every
3–8 seconds; minutes 25–44 were standing poses with pos-
tures changing every 10–48 seconds, and minutes 45–52
were sitting and lying postures lasting 3 minutes and 4.5 min-
utes respectively. Readers are referred to the yoga DVD for
a complete description of the yoga session [57].
%MHR during yoga
0
10
20
30
40
50
60
70
80
90
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 51
Minutes
%MHR
55 %MHR minimum threshold %MHR during yoga
Mean METs and standard deviation per minute during the yoga session (n = 20)Figure 1
Mean METs and standard deviation per minute dur-
ing the yoga session (n = 20). Data from the first four
minutes of the 56 minute yoga practice are not displayed.
The postures used within each section of the yoga practice
(see Table 1) varied in sequence and timing. Minutes 1–24
were sun salutation postures with postures changing every
3–8 seconds; minutes 25–44 were standing poses with pos-
tures changing every 10–48 seconds, and minutes 45–52
were sitting and lying postures lasting 3 minutes and 4.5 min-
utes respectively. Readers are referred to the yoga DVD for
a complete description of the yoga session [57].
Mean METs during yoga
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
1 3 5 7 9 111315171921232527293133353739414345474951
Minutes
METs
3.0 METs minimum value for moderate exercise Mean METs during yoga
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substantial variation in metabolic costs occurs during the
yoga session as can be seen in Figures 1 and 2. A substan-
tial time period of the yoga practice (54%) was engaged in
sun salutation postures which had metabolic values
which were significantly higher than values for treadmill
walking at 3.2 kph, were not significantly different than
the recommended minimum values for moderate levels of
exercise intensity (3.0 METs) [12], and were not signifi-
cantly different from the minimum recommendations of
the ACSM Position Stand for %MHR (55%, [13]) for car-
diovascular fitness. Therefore, yoga practice with a portion
of sun salutation postures exceeding the recommended
minimum bout of 10 minutes [13] may contribute some
portion of sufficiently intense physical activity to improve
cardio-respiratory fitness. This being said, there are two
important caveats regarding this suggestion. First, the cri-
terion used for comparison in this study is the minimum
value suggested by the ACSM Position Stand [13]
(55%MHR). This value applies only to sedentary or unfit
individuals, and therefore may not be a sufficiently high
threshold for individuals who are currently fit (for more
fit individuals the recommendations suggest a minimum
of 65% MHR [13]). Second, ACSM Position Stand recom-
mendations use %MHR as an indirect measure of cardio-
respiratory demand based on the assumption of a rela-
tively linear relationship between %MHR and oxygen
consumption. However, there is evidence that during
yoga, %MHR overestimates the amount of oxygen con-
sumption used [49,51] and consequently %MHR may not
be a sufficiently accurate measure of oxygen consumption
during a yoga practice. Therefore, %MHR used in this
study may be overestimating the intensity of the cardio-
respiratory demand, and caution should be taken in con-
sideration of this suggestion.
This study also demonstrated that individuals performing
an identical yoga session (n = 7) on two occasions expend
very similar amounts of energy (ICC = .979). This finding
suggests that the use of mean metabolic values for quanti-
fying energy cost of yoga across sessions is sufficiently
consistent to provide a basis for valid estimates.
As is typical of most yoga classes, the yoga practice in this
study ended with several minutes of supine relaxation
(e.g., shavasana). The post hoc findings that METs and
%MHR in the final three minutes of this relaxation were
not significantly different from the mean value found in
the initial resting period suggest that the increased meta-
bolic demand of yoga was unlikely to have contributed to
metabolic measures during the treadmill activity. In fur-
ther support of this, the mean value (3.3) for the treadmill
METs found in this study during the 4.8 kph was identical
to the normative value suggested by Ainsworth for level
treadmill walking at this same speed [58].
Placing the findings of the current study into a larger dis-
cussion of the potential for the physical activity compo-
nent of yoga to provide health benefits requires
consideration of the continuum of benefits that can be
gained from increases in physical activity. The ACSM Posi-
tion Stand [13] recommendations acknowledge that
lower levels of physical activity than those recommended
may provide health benefits for those who are quite unfit,
particularly in the area of metabolic fitness [13]. Meta-
bolic fitness [59,60] describes the ability of metabolic sys-
tems predictive of risk of cardiovascular disease (e.g.,
diabetes) to improve through intensities of physical activ-
ity which do not produce change in aspects of perform-
ance such as VO
2
max. For example, in relation to obesity
and Type II diabetes, overweight/obese individuals who
increase physical activity can reduce insulin resistance
even in the absence of concurrent weight loss [61-64].
Similarly among the non-obese, physical activity per-
formed at levels insufficient to influence body mass or
maximal oxygen uptake, can still improve insulin action
[65]. The relatively low level of physical activity found in
this study may serve to increase metabolic fitness despite
being insufficient to create gains in cardio-respiratory fit-
ness. This suggestion is in agreement with studies which
have found yoga to improve indices associated with met-
abolic fitness such as insulin resistance [66,67] and lipid
profiles [68,69].
Table 3: Results of one sample t-tests of mean METS and %MHR compared to recommended constant minimums
Variable Comparison value Difference between mean
and comparison value
Standard Deviation t statistic P value
Mean %MHR* across entire yoga session (n = 18) 55% MHR [13] -5.6 12.24 -14.38 < 0.0001
Mean %MHR* during sun salutation portion of yoga
session (n = 18)
55% MHR [13] -0.17 11.77 -0.30 0.7664
Mean METs across entire yoga session (n = 20) 3.0 METs [12] -0.54 0.83 -20.81 < 0.0001
Mean METs during sun salutation portion of yoga
session (n = 20)
3.0 METs [12] -0.09 0.78 -2.80 < 0.0053
Note: *All values for MHR based on n = 18. Values for METs based on n = 20. MHR = Maximum predicted heart rate; METs = Metabolic
equivalents;
BMC Complementary and Alternative Medicine 2007, 7:40 http://www.biomedcentral.com/1472-6882/7/40
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There is a great deal of evidence that yoga or yoga based
interventions reduce blood pressure and heart rate [23-
42], and a recent systematic study suggests that over 85%
of relevant studies published since 1970 demonstrate evi-
dence that yoga reduces sympathetic tone, increases para-
sympathetic tone and improves cardiovagal function [42].
The mechanisms by which yoga conveys health benefits
have received little study. However, given the findings of
this study, as well as the study by Clay et al., it is unlikely
that the well documented health effects across multiple
systems are due solely to the low levels of physical activity
within yoga practice. Yoga is a mind-body practice involv-
ing multiple integrated elements (e.g., conscious control
of the breath, postures, meditation) [70]. The relative
influence and interactions of these elements on health
outcomes are unknown. In short, yoga may convey health
benefits which are unrelated, or only partially related, to
the physical activity component of yoga practice.
This study was limited in that it was a sample of conven-
ience in which 90% of the subjects were women, and all
were recruited from a private university and various urban
yoga studios. Although, as mentioned previously, remov-
ing the two male participants from the data did not alter
any of the results, it remains unclear whether a sample
including more male participants would have altered the
findings. All subjects were relatively young, healthy, and
of normal weight and therefore the results may not be
generalizable to persons suffering from adverse health
conditions, those with very high or very low BMI, the eld-
erly, or children under eighteen. The yoga DVD was cho-
sen to represent the typical length, intensity, and variety of
poses in a beginner yoga class, however, we have no infor-
mation to determine the degree to which it is genuinely
representative of yoga classes performed in the United
States. Certainly, the results cannot be used to generalize
to moderate or advanced level yoga classes. Also, as all
subjects were moderate-to-advanced yoga practitioners, it
is unclear how yoga experience may have influenced the
findings in comparison to those who may be yoga nov-
ices. The lack of randomization of activities is a limitation
in this study, suggesting that even though the study found
that metabolic rate and %MHR returned to baseline after
the yoga practice, possible influence upon the treadmill
activities cannot be totally eliminated. Finally, in addition
to the limitations described earlier relative to %MHR, we
acknowledge that the true relative intensity of physical
activity for each participant was not known as the VO
2
max was not measured in this study, and consequently,
more accurate data regarding each participant's percent-
age of VO
2
max was not available.
Conclusion
Metabolic costs of yoga averaged across the entire session
represent low levels of physical activity, similar to walking
on a treadmill at 3.2 kph, and do not meet recommenda-
tions for levels of physical activity for improving or main-
taining health [12] or cardiovascular fitness [13]. Yoga
practice with a portion of sun salutation postures exceed-
ing the minimum bout of 10 minutes may contribute
some portion of sufficiently intense physical activity to
improve cardio-respiratory fitness in unfit or sedentary
individuals. The measurement of energy expenditure
across yoga sessions is highly reliable.
Competing interests
The author(s) declare that they have no competing inter-
ests.
Authors' contributions
MH and AR conceived of the study, participated in its
design and coordination, and assisted with data analysis
and drafting of the manuscript. WM performed data col-
lection, assisted with organization and analysis of the data
and drafting of the manuscript. All authors read and
approved the final manuscript.
Acknowledgements
The authors would like to thank the following for their contributions: the
staff of the Energy Expenditure Sub-Core at St. Luke's Roosevelt Hospital
for their patience and flexibility; all of the Manhattan yoga studios which
provided participants: Bikram Yoga NYC, Levitate Yoga, Naga Yoga, and
World Yoga Center; and lastly, the study participants themselves, without
whom this work would not have been possible.
This research was supported by a grant from the National Cancer Insti-
tute:U54; CA101598-01
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Pre-publication history
The pre-publication history for this paper can be accessed
here:
http://www.biomedcentral.com/1472-6882/7/40/prepub
... After title and abstract screening, 9,774 papers were eliminated based on the exclusion criteria, 6 additional papers were obtained from hand searches leaving 140 records for full-text review. The full-text review excluded 125 papers resulting in a total of 15 studies that met the inclusion criteria, [23,35,36,[43][44][45][46][47][48][49][50][51][52][53][54]. Common reasons for exclusion were participant age exceeded 65 years; exercise modality was not walking; and a direct comparison between a relative and absolute measure of physical activity was missing. ...
... However, several measures were used for relative intensity. The most common relative method was %HRR (8 studies) [36,46,48,[50][51][52][53][54], followed by %HR max (3 studies) [52][53][54], %VO 2max / %VO 2peak (3 studies) [23,35,46], %VO 2 R (2 studies) [46,50], lactate thresholds (2 studies) [23,51], and HR index (1 study) [43]. This large variation in relative intensity methods may indicate why METs have become a popular choice among research and industry professionals as their use has been standardised as a measure of intensity. ...
... However, several measures were used for relative intensity. The most common relative method was %HRR (8 studies) [36,46,48,[50][51][52][53][54], followed by %HR max (3 studies) [52][53][54], %VO 2max / %VO 2peak (3 studies) [23,35,46], %VO 2 R (2 studies) [46,50], lactate thresholds (2 studies) [23,51], and HR index (1 study) [43]. This large variation in relative intensity methods may indicate why METs have become a popular choice among research and industry professionals as their use has been standardised as a measure of intensity. ...
Full-text available
Article
Introduction A metabolic equivalent (MET) is one of the most common methods used to objectively quantify physical activity intensity. Although the MET provides an ‘objective’ measure, it does not account for inter-individual differences in cardiorespiratory fitness. In contrast, ‘relative’ measures of physical activity intensity, such as heart rate reserve (HRR), do account for cardiorespiratory fitness. The purpose of this systematic review with meta-regression was to compare measures of absolute and relative physical activity intensity collected during walking. Methods A systematic search of four databases (SPORTDiscus, Medline, Academic Search Premier and CINAHL) was completed. Keyword searches were: (i) step* OR walk* OR strid* OR "physical activity"; (ii) absolute OR “absolute intensity” OR mets OR metabolic equivalent OR actigraph* OR acceleromet*; (iii) relative OR “relative intensity” OR "heart rate" OR "heart rate reserve" OR “VO 2 reserve” OR VO 2 * OR “VO 2 uptake” OR HRmax* OR metmax. Categories (i) to (iii) were combined using ‘AND;’ with studies related to running excluded. A Bayesian regression was conducted to quantify the relationship between METs and %HRR, with Bayesian logistic regression conducted to examine the classification agreement between methods. A modified Downs and Black scale incorporating 13 questions relative to cross-sectional study design was used to assess quality and risk of bias in all included studies. Results A total of 15 papers were included in the systematic review. A comparison of means between absolute (METs) and relative (%HRR, %HR max , %VO 2 R, %VO 2max , HR index ) values in 8 studies identified agreement in how intensity was classified (light, moderate or vigorous) in 60% of the trials. We received raw data from three authors, incorporating 3 studies and 290 participants. A Bayesian random intercept logistic regression was conducted to examine the agreement between relative and absolute intensity, showing agreement in 43% of all trials. Two studies had identical relative variables (%HRR) totalling 240 participants included in the Bayesian random intercept regression. The best performing model was a log-log regression, which showed that for every 1% increase in METs, %HRR increased by 1.12% (95% CI: 1.10–1.14). Specifically, the model predicts at the lower bound of absolute moderate intensity (3 METs), %HRR was estimated to be 33% (95%CI: 18–57) and at vigorous intensity (6 METs) %HRR was estimated to be 71% (38–100). Conclusion This study highlights the discrepancies between absolute and relative measures of physical activity intensity during walking with large disagreement observed between methods and large variation in %HRR at a given MET. Consequently, health professionals should be aware of this lack of agreement between absolute and relative measures. Moreover, if we are to move towards a more individualised approach to exercise prescription and monitoring as advocated, relative intensity could be more highly prioritised.
... The beneficial effects of yoga on hypertension may occur through its blood pressure-lowering effect (11), as well as its effects on physical activity, stress reduction, and lifestyle (16)(17)(18)(19). The exact mechanism of yoga for lowering blood pressure is not known yet but proposed physiological mechanisms include an increase in parasympathetic activity, possibly due to vagal stimulation, the suppression of the hypothalamic-pituitaryadrenal axis, and reduction in the activity and reactivity of the sympathetic nervous system (20)(21)(22)(23). ...
... Yoga, as physical activity, can satisfy the recommended levels of physical activity for people with hypertension. For example, one study found that an hour of Ashtanga yoga satisfies the moderate levels of physical intensity (16) and another study found that 1.5 h of Vinyasa yoga is higher than moderate physical activity requirements (24). 2020 ISH Global Hypertension Practice Guidelines also suggest yoga as an aerobic form of physical activity under lifestyle modification (8). ...
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Objectives: This systematic review aimed to synthesize the content, structure, and delivery characteristics of effective yoga interventions used for managing hypertension and to compare these characteristics with ineffective interventions. Design and Method: The JBI and the PRISMA guidelines were followed in this systematic review. RCTs conducted among hypertensive adults were included. RCTs reporting at least one of the major components of yoga (i.e., asana, pranayama, and dhyana and relaxation practices) and comparing them with no intervention or any intervention were eligible. Sixteen databases were searched for published and unpublished studies without any date and language restrictions till March 15, 2021. Results: The literature search yielded 13,130 records. 34 RCTs (evaluating 38 yoga interventions) met the inclusion criteria. Overall, included studies had low methodological quality mostly due to inadequate reporting. Yoga reduced SBP and DBP compared to a control intervention (MD −6.49 and −2.78; 95CI% −8.94-−4.04 and −4.11-−1.45, respectively). Eighteen, 14 and 20 interventions were effective in improving SBP, DBP, or either, respectively. 13 out of 20 effective interventions incorporated all the 3 major components of yoga and allocated similar durations to each component whereas ineffective interventions were more focused on the asana and duration of asana practice was longer. The most common duration and frequency of effective interventions were 45 min/session (in 5 interventions), 7 days/week (in 5 interventions), and 12 weeks (in 11 interventions) whereas the most common session frequency was 2 days a week (in 7 interventions) in ineffective interventions. Effective interventions were mostly center-based (in 15 interventions) and supervised (in 16 interventions) and this was similar with ineffective interventions. Conclusion: Despite the low quality and heterogeneity of included studies, our findings suggest yoga interventions may effectively manage hypertension. The differences between the effective and ineffective interventions suggest that effective yoga interventions for managing hypertension yoga interventions mostly incorporated asana, pranayama, and dhyana and relaxation practices and they had a balance between these three components and included regular practice. They were mostly delivered in a center and under supervision. Future studies should consider developing and evaluating an intervention for managing hypertension using the synthesized findings of the effective interventions in this review. Systematic Review Registration: [PROSPERO], identifier [CRD42019139404].
... Yoga, an alternative mindful exercise that is commonly performed at light-to-moderate intensities [4,5], is practiced by an estimated 10% of U.S. adults [6]. It has shown some promise as an adjuvant for treating anxiety and its comorbidities of depression, sleep disorders, and schizophrenia [7][8][9][10]. ...
... Page 3 of 7 100 ± 20 bpm, 50% ± 10% of age-estimated maximum HR. Heart rate during Hatha Yoga in practitioners typically ranges between 80 to 115 bpm, or about 50-55% of maximum HR [4,5]. Heart rate did not change during quiet rest (p= .414) ...
... It has been reported that yoga at varying tempos can meet or exceed moderate-intensity exercise recommendations (3.0-5.9 metabolic equivalents (METs)) [14], serving as an alternative, low-impact training solution for overweight and obese populations with no prior exercise experience and poor cardiorespiratory and musculoskeletal fitness levels [99]. However, a 56-min Hatha yoga session provoked lower responses in exercise intensity (49.4% MHR, RPE 12-13) and energy expenditure (3.2 kcal/min, 2.5 METs) compared with the above suggested levels in healthy young adults with at least one year of experience in yoga practice [100]. Additionally, a 35-min Hatha yoga session performed by healthy young adults who had been practicing yoga for 6-10 years, showed similar exercise intensity (52.3-54.5% MHR) and energy expenditure (1.3-2.5 kcal/min, 1.0-2.2 ...
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Physical activity has been documented as a foundational approach for weight management and obesity, improving several cardiometabolic and mental health indices. However, it is not clear whether yoga practice can induce beneficial improvements in anthropometric and body composition parameters, performance, metabolic health, and well-being among overweight/obese people. The aim of this topical review was to catalog training studies examining the psychophysiological responses to yoga interventions in order to detect which outcomes have been investigated, the research methods applied, and the conclusions. The inclusion/exclusion criteria were met by 22 published articles involving 1178 (56% female) overweight/obese participants. This brief review on yoga-induced adaptations demonstrates that this widely used meditative movement activity can meaningfully improve the vast majority of the selected markers. These beneficial alterations are focused mostly on various anthropometric and body composition variables, cardiovascular disease risk factors, physical fitness parameters, quality of life, and stress in previously inactive overweight/obese individuals. Instead, yoga-based physical exercise interventions investigating anxiety, depression, mood state, exercise enjoyment, affect valence, and adherence were limited. Further research should focus on the yoga intervention configuration and potential mechanisms behind favorable changes in various psychophysiological indices through large-scale, rigorously designed randomized controlled trials implementing long-term interventions in overweight/obese individuals.
... Being the first study to investigate the energy costs of QMT there are no other studies to use as a direct comparison. However, the metabolic demands of several other novel and/or alternative forms of exercise have been investigated including yoga (20,29,30) and pole dancing (31). Both practices share similarities in class design to AF as they generally begin with a gradual warmup, followed by a skills segment and a routinesegment. ...
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Background: Quadrupedal movement training (QMT) is a novel alternative form of exercise recently shown to improve several fitness characteristics including flexibility, movement quality, and dynamic balance. However, the specific energy demands of this style of training remain unknown. Therefore, the purpose of this study was to compare the energy expenditure (EE) of a beginner-level quadrupedal movement training (QMT) class using Animal Flow (AF) to walking, and to compare EE between segments of the AF class and gender. Methods: Participants (15 male, 15 female) completed 60-min sessions of AF, treadmill walking at a self-selected intensity (SSIT) and treadmill walking at an intensity that matched the heart rate of the AF session (HRTM). Indirect calorimetry was used to estimate energy expenditure. Results: AF resulted in an EE of 6.7 ± 1.8 kcal/min, 5.4 ± 1.0 METs, and HR of 127.1 ± 16.1 bpm (63.4 ± 8.1% of the subjects' age-predicted maximum HR), while SSIT resulted in an EE of 5.1 ± 1.0 kcal/min, 4.3 ± 0.7 METs, HR of 99.8 ± 13.5 bpm (49.8 ± 6.7% age-predicted maximum HR), and HRTM resulted in and EE of 7.6 ± 2.2 kcal/min, 6.1 ± 1.0 METs, and HR of 124.9 ± 16.3 bpm (62.3 ± 8.2% age-predicted maximum HR). Overall, EE, METs, HR and respiratory data for AF was greater than SSIT (p's < 0.001) and either comparable or slightly less than HRTM. The Flow segment showed the highest EE (8.7 ± 2.7 kcal/min), METs (7.0 ± 1.7) and HR (153.2 ± 15.7 bpm). Aside from HR, males demonstrated greater EE, METs, and respiratory values across all sessions and segments of AF than females. Conclusions: QMT using AF meets the ACSM's criteria for moderate-intensity physical activity and should be considered a viable alternative to help meet physical activity guidelines.
... Hagins [33] 2007 Healthy yoga practitioners (20) Asana Treadmill walking Single session VO 2 max, HR, %MHR, METs, and energy expenditure (kcals) ...
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College students are dependent upon a significant time of psychological development, experiencing a thorough trial study, and concentrating how to work freely. It has been exhibited that physical exercises, including running and bicycling, support well-being and smooth strain. Understudies at the college additionally have poor physical movement rates. Yoga is an old mental and physical exercise which influences the state of mind and stress. Be that as it may, concentrates in peer-evaluated diaries looking at the psychophysiological impacts of yoga are phenomenal. The objective of this examination is to build up starter proof for the psychophysiological impacts of yoga on worry in understudies at school and youthful grown-ups. An accentuation has likewise been put on the psychological and physical well-being of clinical understudies. The current survey article proposed that yoga effectively affects a psychophysiological level that prompts lower pressure rates in college students.
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The study aimed to examine the Teacher's motivation and encouragement towards their children to participate in physical activities. the teachers who have children studying in the higher secondary schools in Bannu District, Khyber Pakhtunkhwa, Pakistan was the population of the study. This study was focused to analyze the views of teachers regarding motivation and encouragement towards their children to participate in physical activities to find out the most dominant motives that persuade parents to encourage their children to participate in sports activities. It has been concluded that teachers’ involvement in sports in terms of their attitude, perception and motives has paramount significance in motivating children towards participation in sports. Researchers can investigate the motives among the teachers in other provinces of the country and for this purpose comparison of the motives can be done.
... Game aspects and physical exercise are claimed as an effective tool helps in the control of obesity, high blood pressure, high cholesterol, including the prevention of heart disease and osteoporosis. Practicing physical activity satisfy recommendations for intensity of sports activities which improve and maintain health and cardiovascular fitness (Hagins, Moore, and Rundle, 2007). There has been a misconception that sports are prohibited in Islam and Muslimsocieties do not allow sports participation, particularly to the women folk. ...
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The aim of the study was to investigate the Parental Motives behind their Children Participation in Sports Activities. The population of this study comprised all the parents whose children were on role in government primary schools of Khyber Pakhtunkhwa, Pakistan. There were total 50,000 (Fifty Thousands)parents whose children were on role in government primary schools of district bannu (Official Gateway Khyber Pakhtunkhwa, 2014). Convenient sampling procedure was adopted to collect the required information from the respondents; there was 500 sample of the study. The present study was carried out in the district Bannu KP Pakistan. Percentage, Mean and Standard Deviation was used for set hypotheses. It was found that that parent’s involvement in sports in terms of their attitude, perception and motives has paramount significant in motivating children towards participation in sports, it was also heighted that that most of the parents wants to allow their children to participate in sports activities but financial limitation create hindrance in the way of their children sports participation. It was recommended by the researcher that Different kinds of sports program may be undertaken to increase sports participation right from gross roots level i.e. union council, tehsil and district level.
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Background Participating in yoga may be ideal for college students to increase physical activity and improve mental health. Purpose To investigate the feasibility and impact of an 8-week yoga intervention within a university setting on mental and physiologic heath. Methods This 8-week yoga intervention included twelve yoga-naïve adults, (23.8 ± 4.6 years; 71% female). Participants attended two 60-min yoga classes/week in addition to baseline, mid- and post-lab visits. Results 83% of participants attended ≥75% of yoga classes. Stress and depression symptoms decreased by 11% and 25%, respectively and erythrocyte sedimentation rate (ESR) reduced by 28%. Participants did not meet physical activity recommendations observed greater improvements in stress, depression symptoms, ESR, and C-reactive protein compared to participants who met recommendations. Conclusion The majority of participants attended ≥12 of 16 yoga classes. Exploratory analyses provide preliminary support for the impact of yoga on reducing stress, symptoms of depression, and ESR. Participants who were not meeting physical activity guidelines prior to starting the intervention received greater benefits.
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Pranayama is a basic yogic breathing technique, of which one of the methods is nadisodhana wherein breathing is performed through alternate nostrils. The present study aims at identifying the energy cost of nadisodhana and compare it with standard physical activities such as controlled treadmill-walking and field-walking. The present study was conducted on twelve normal healthy male volunteers who have been practicing yoga and pranayama over a period of three years. The energy cost of nadisodhana and field-walking was derived from individual regression equations using oxygen consumption and heart rates recorded during a maximal graded exercise test on treadmill carried out in a thermoneutral environment. The predicted oxygen consumption and heart rate during nadisodhana were significantly lower than in field-walking (p<0.05&0.01) and treadmill-walking (p<0.01& 0.01) indicating that the energy cost for nadisodhana is lower. Oxygen pulse during nadisodhana was also significantly lower than field-walking (p<0.05) and treadmill-walking (p<0.05). It was also observed that during nadisodhana blood lactate was significantly lower (p<0.01&0.05) than during the other two tests studied and pyruvate was significantly higher (p<0.01) than during treadmill-walking. The results indicate low exertion on the subjects, based on Borg scale during nadisodhana than in other forms of physical exercises. This low exertion may be attributed to efficient metabolic adaptations during nadisodhana. In view of the above findings nadisodhana can be included in the battery of fitness programs for both healthy and diseased individuals.
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Although a variety of psychological benefits have been attributed to regular exercise, few experimentally controlled studies of healthy individuals currently exist. One hundred twenty healthy, sedentary, middle-aged men and women were randomly assigned to either a 6-month home-based aerobic exercise training program or to an assessment-only control condition. Adherence across the 6-month period was found by both self-report and heart rate microprocessor methods to exceed 75% in both sexes. To assess changes in a variety of psychological variables over time, a 14-item Likert rating scale was completed and returned on a biweekly basis throughout the 6-month period. Slope analyses conducted on the 11 items attaining acceptable test-retest reliability coefficients showed significant between-groups differences on the 3 items most closely associated with the actual physical changes that occurred with exercise (all ps less than.004). Implications in relation to repeated measurement of psychological changes in nonclinical populations and the determination of the relevant population-, activity-, and program-specific parameters involved are discussed. Language: en