Rashmi Vyas and Nirupama Dikshit Indian journal of physiology and pharmacology 11/2002; 46(4):487-91

1. Effect of Meditation on Respiratory System, Cardiovascular
System and Lipid Profile
RASHMI VYAS* AND NIRUPAMA DIKSHIT
Department of Physiology,
B. J. Medical College,
Ahmedabad – 380 016
*Corresponding Author and present address:
Department of Physiology, Christian Medical College and civil
(Received on July 16, 2001)
Abstract: In this study, respiratory functions, cardiovascular parameters and lipid
profile of those practicing Raja Yoga meditation (short and long term meditators) were
compared with those of nonmeditators. Vital capacity, tidal volume and breath holding
were significantly higher in short and long term meditators than nonmeditators. Long
term meditators has significantly higher vital capacity and expiratory pressure than
short and long term meditators than nonmeditators. Long term meditators had
significantly higher vital capacity and expiratory pressure than short term meditators.
Diastolic blood pressure was significantly lower in both short and long term meditators
as compared to nonmeditators. Heart rate was significantly lower in long term
meditators than in short term meditators and nonmeditators. Lipid profile showed a
significant lowering of serum cholesterol in short and long term meditators as
compared to nonmeditators. Lipid profile of short and long term meditators was better
than the profile of nonmeditators inspite of similar physical activity. This shows the
Raja Yoga meditation provides significant improvements in respiratory functions,
cardiovascular parameters and lipid profile.
Key words: meditation raja yoga lipid profile
cardiovascular parameters respiratory functions
INTRODUCTION
Yoga and meditation have been extensively studied for their beneficial effects on
human health (1, 2). Most of the physiological studies on meditation are in the arena of

2. transcendental meditation (3). Other forms of meditation have not been extensively
studied. The present study is aimed at determining the effect of Raja Yoga Meditation
on respiratory functions, cardiovascular parameters and lipid profile. The study was
performed on subjects who did not differ significantly in age, sex distribution and
physical activity.
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METHODS
The study was conducted on 105 human volunteers of either sex divided into three
groups-non meditators, short term meditators (meditating for 6 months to 5 years) and
long-term meditators (meditating for more than five years). The non-meditators were a
mixed group of students and staff of B. J. Medical College and Civil Hospital,
Ahmedabad who had never done any kind of meditation. The meditators were
practicing Raja Yoga meditation for 1 hour every morning (7.30 A.M. – 8.30 .M.) at
the local Brahmakumari Centre, Ahmedabad. In Raja Yoga meditation the individual
uses visual or auditory images for concentration which helps one to proceed to
meditation.
Details of age, sex, smoking, intake of alcohol, physical exercise undertaken if any,
dietary habits (whether vegetarian or non vegetarian) are given in Table I. All
measurements except heart rate were performed in the local Brahmakumari center on
meditators and in the Physiology department, B. J. Medical College, Ahmedabad on the
non-meditators. Heart rate was inferred from E.C.G. taken in the E.C.G. laboratory for
all the subjects. All observations were made between 8:30 A.M. and 9:30 A.M.
Sufficient time (15 min) was given to the nonmeditators to relax before recording the
parameters. The venues chosen for measurement of parameters were familiar to the
subjects.
Blood pressure was recorded using a sphygmomanometer. ECG was recorded by an
ECG machine (108 T, BPL) using standard chest and limb leads. Heart rate was
calculated from the tracings. Each ECG was reported by a trained physician. In
respiratory function, the following parameters were assessed:- tidal volume, vital
capacity, breath holding and expiratory pressure. The tests wee thoroughly explained

3. and each subject was given three trials. In case of tidal volume the average of three
readings was taken and in cases of vital capacity and breath holding the highest reading
was considered. Tidal volume and vital capacity were measured with Wright
Respirometer Mark 8 (Farriers Medical Limited, London). Breath holding was
measured on a stopwatch till the breaking point of the held
breath. Expiratory pressure was recorded through a manometer by the standard
procedure.
To assess the lipid profile 5 ml of blood was collected. Serum cholesterol, triglyceride
and HDL was estimated by their respective reagent sets from Labcare, Baroda and the
readings taken on a RA-50 chemistry analyzer.
Statistical methods used:
Descriptive statistics of mean, standard deviation and percentages were used to display
the continuous (age, respiratory functions, cardiovascular parameters, lipid profile) and
categorical (sex, physical exercise, smoking, drinking and diet) variables of the three
groups respectively. One way analysis of variance was applied to find the significance
of differences between the three groups. In addition, the groups significantly different
at 5% level by ANOVA were subjected to Bonferroni multiple comparisons procedure.
Categorical independent variables were analyzed for association with the three groups
using Pearson’s Chi-square test.
RESULTS
The subjects in the three groups did not show significant difference in age, sex
distribution and physical activity (Table I). The dietary habit of meditators showed a
significant difference from non-meditators but as the number of non-vegetarians is
small (9 out of the 105 subjects) the P value should be interpreted with caution. (Table
I) None of the subjects were smokers or consumers of alcohol.
TABLE I: Distribution of demographic characteristics
Variables Non
meditators
n(%)
Short term
meditators
(n%)
Long term
meditators
n(%)
P
Age (mean ± 52.6±12.2 46.6±13.3 52.9±12.4 0.06

4. SD)
Sex 1. Male
2. Female
12(34.3)
23 (65.7)
12 (34.3)
23 (65.7)
18 (51.4)
17 (48.6)
0.24
Physical
Exercise
1. Sedentary
2.Non
Sedentary
29 (82.9)
6 (17.1)
29 (82.9)
6 (17.1)
26 (74.3)
9 (25.7)
0.58
Diet Non-Veg
Veg
9 (25.7)
26 (74.3)
0
35 (100)
0
35 (100)
0.00
None were smokers or consumers of alcohol.
Sedentary: No physical exercise; Non Sedentary: Regular physical exercise every day.
TABLE II: Respiratory, cardiovascular and lipid parameters in the groups.
Variables Non
meditators
Short term
meditators
Long term
meditators
P
Tidal
Volume
(ml) mean ±
SD
272.8±165.0 557.7±220.1* 579.9±140.5* 0.0000
Vital
Capacity
(ml) mean
±SD
2176.3±844.7 3358.0±905.5* 3931.7±798.8** 0.0000
Breath
Holding
(sec)
median
(min., max.)
20.0(5,60) 35 (20,90)* 40 (20,65)* 0.0000
Expiratory
pressure
53.9±27.8 65.1±30.3 91.5±33.3** 0.0000

5. (mmHg)
mean ± SD
Systolic
Blood
Pressure
(mmHg)
mean ± SD
133.7±17.1 137.8±17.4 140.7±20.9 0.2857
Diastolic
Blood
Pressure
(mmHg)
mean ±SD
92.7±8.6 87.1±10.2* 84.0±7.1* 0.0003
Heart Rate
(min.) mean
± SD
84.7 ±12.6 90.8±11.8 74.6±10.6 0.0000
Cholesterol
(mg/dl)
mean ± SD
293.0±67.9 240.6±69.1* 235.4±94.5* 0.0040
Triglyceride
(mg/dl)
median
(min. max.)
141.5
(64,2,435.3)
105 (19,409.4) 123 (51,212.6) 0.0401
HDL
(mg/dl)
median
(min. max.)
46 (24, 120) 44 (24,99) 52 (38,76) 0.2431
*significantly different at 5% level from Non mediators.
*significantly different at 5% level from Short term meditators.
Table II shows that tidal volume, vital capacity and breath holding are significantly
higher in short and long term meditators as compared to non meditators. Only vital
capacity and expiratory pressure are significantly higher in long term meditators as

6. compared to short term meditators. Diastolic blood pressure is significantly lower in
both short and long term meditators as compared to non-meditators. Heat rate is
significantly lower in long-term meditators as compared to non-meditators and short
term meditators. Systolic blood pressure shows no significant difference between the
three groups.
Electrocardiogram showed no particular pattern or significant changes except for
changes in heart rate. Cholesterol is significantly lower in both short and long term
meditators as compared to non-meditators. Though triglyceirde showed a significant P
value with ANOVA, further analysis with Bonferroni test showed no significant
difference between the three groups. There was no significant difference in HDL values
between the three groups.
DISCUSSION
Improvements in cardio respiratory parameters and lipid profile seen in the meditators
in our study are similar to other studies done on meditation (3, 4, 5) and yoga (6, 7).
Although clear cut evidence is lacking, the mechanisms by which changes in
respiratory functions occur are: greater relaxation of respiratory muscles induced by
supraspinal mechanisms which increase expiratory reserve volume contributing to a
rise in vital capacity.
Lung inflation to near total lung capacity is a major physiological stimulus for release
of surfactant and prostaglandin into alveolar spaces. This causes increase in lung
compliance and a decrease in bronchiolar smooth muscle tone (8, 9). Lung inflation to
near total lung capacity as induced by relaxation during meditation may thus lead to a
better vital capacity. The increased breath holding time caused by greater control of
respiratory musculature and the ability to consciously override the normal
physiological stimuli of respiratory centers has been reported in the study on those
doing yoga (10). Perhaps a similar mechanism comes to play here.
The wakeful hypo-metabolic state as characterized by decreased CO2 production and
decreased O2 consumption can also help to hold the breath for a longer time. (3, 11).
The decrease in heart rate and diastolic blood pressure indicate a shift in the balancing
components of autonomic nervous system towards the parasympathetic state (1).

7. Meditation by modifying the state of anxiety (1) reduces stress induced sympathetic
over activity resulting in a lowering of diastolic blood pressure and heart rate. It makes
the subject undergo relaxation and thereby decrease arterial tone and peripheral
resistance (12, 13). This may be another reason for a fall in diastolic blood pressure.
Long-term meditation seems to confer further improvement of certain parameters
measured (vital capacity, expiratory pressure and heart rate) indicating a continued
alteration of the physiological processes involved.
Our findings on changes in the cholesterol level are similar to those reported in
transcendental meditation (2, 14). A decrease in sympathetic discharge and better
ability to overcome stress can be cited as possible mechanisms for this change. Even
though in our subjects the level of physical activity was similar the meditators had a
significantly lower cholesterol level.
In summary our study indicates that Raja Yoga meditation confers significant benefits
in respiratory functions, cardiovascular parameters and lipid profile which continued to
improve further with long-term meditation.
ACKNOWLEDGEMENTS
We thank all the subjects for their cooperation and all of the stall of the Department of
Physiology, B. J. Medical College, Ahmedabad especially Dr. C. A. Desai, former
Professor and Dean Dr. R. C. Shah and Dr. K. V. Raval for the help rendered.
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