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International Journal of Basic and Applied Medical Sciences ISSN: 2277-2103 (Online)
An Online International Journal Available at http://www.cibtech.org/jms.htm
2011 Vol. 1 (1) September-December, pp.144-148/Kiran et al.
Research Article
144
IMPACT OF MEDITATION ON AUTONOMIC NERVOUS SYSTEM- A
RESEARCH STUDY
*Kiran1, Anterpreet K Arora2, Deepinder Kaur1 and Richa Ghay1
1Department of Physiology, Sri Guru Ram Das institute of Medical Sciences and Research, Amritsar,
India (SGRD)
2Department of Anatomy SGRD Institute of Medical Sciences and Research, Amritsar, India
*Author for Correspondence
ABSTRACT
Meditation is a complex physiological process which affects neural, psychological, behavioral, and
autonomic functions, and is considered as an altered state of consciousness, differing from wakefulness,
relaxation at rest, and sleep. Health professionals are also enthusiastic about meditation. There is much of
clinical evidence to suggest that the activity of autonomic nervous system is affected by meditation. The
present study was initiated and an attempt was made to bring out the association of autonomic functions
with meditation. Autonomic Nervous System (ANS) function tests were conducted using Polyrite,
medicare system. One hundred subjects were divided into two groups (meditators and non meditators in
the age group of 25-60 years. The autonomic insufficiency was ruled out in all. The sympathetic activity
of ANS was compared by Galvanic skin resistance (GSR), Cold pressor response (CPR) and Hand grip
test and the parasympathetic activity was compared by standing to lying ratio (30:15) , valsalva ratio and
tachycardia ratio. The results were statistically analyzed in each group and valid conclusions were drawn.
The result on comparison of various autonomic function tests amongst meditators and non-meditators of
same age group suggested that the parasympathetic activity was more in meditators males & females
while sympathetic activity was less.
Key Words: Autonomic Function Tests, Meditators, Non-Meditators, Parasympathetic, Sympathetic
INTRODUCTION
It is thought that some types of meditation might work by reducing activity in the sympathetic nervous
system and increasing activity in the parasympathetic nervous system.
In one area of research, scientists are using sophisticated tools to determine whether meditation is
associated with significant changes in brain function. A number of researchers believe that these changes
account for many of meditation's effects NCCAM (2010).
It is also possible that practicing meditation may work by improving the mind's ability to pay attention.
Since attention is involved in performing everyday tasks and regulating mood, meditation might lead to
other benefits NCCAM (2010).
Meditation is a technique of autogenic relaxation. It claims to deal with the inner world. It is a technique
of self-exploration. Regular practice of meditation and various yogic exercises have been observed to
maintain optimal level of autonomic equilibrium at rest and during exposure to stressful conditions
(Selvamurthi, 1984). Meditative practices diminish sympathetic dominance resulting in letter balance
between sympathetic and parasympathetic system (Anand, 1991). Most of the meditation techniques work
by affecting the ANS, in turn regulating many organs and muscles, controlling functions such as the heart
beat, sweating, breathing, and digestion. One possible way for meditation to act on autonomic activity is
through respiration control (Raghavendra, 2011). Both the parasympathetic and sympathetic nervous
system which constitute the autonomic nervous system (ANS) are affected by meditation. A number of
tests have been evolved over a period of time which have been made it possible to assess the functional
status of ANS. The parasympathetic nervous system tests include beat to beat variation, valsalva ratio and
the baroreflexsensivity and sympathetic nervous system tests include the hand grip test, the galvanic skin
resistance and the cold pressor response (Ghai, 2007). Work done over the past few years gives us an
International Journal of Basic and Applied Medical Sciences ISSN: 2277-2103 (Online)
An Online International Journal Available at http://www.cibtech.org/jms.htm
2011 Vol. 1 (1) September-December, pp.144-148/Kiran et al.
Research Article
145
indication of effect of meditation on the autonomic nervous system activity. Meditation is commonly
thought to reduce stress by a combination of two pathways. First, by reducing somatic-arousal
(physiological effects) thereby reducing reactivity of the individual to environmental stressors, and
second, by altering the individual’s cognitive appraisal of and perceived self-efficacy with regard to
stressors Manocha (2011). So a formal study was planned to the carried out which involved a battery of
autonomic tests to be done on meditators and non mediators of same age group. The changes were noticed
in some parameter of both sympathetic and parasympathetic function tests amongst meditators and non
meditators of same age group.
MATERIALS AND METHODS
The present study was conducted in the Department of Physiology, SGRDIMSAR, Amrtisar. It was
conducted in 100 healthy subjects both males and females, selected from Brahma Kumari Ashram in the
city and perform Raj Yoga meditation regularly. Out of 100 subjects fifty healthy persons in the age
group of 25-60 years were mediators who regularly do meditation for one hour a day while rest fifty
healthy persons in the same age group were non meditators who visit the same Ashram but do not
perform meditation. The anthropometric measurements were carried out in all the groups. History taking
and medical examination was carried out .The nature of the test was explained to the subjects. All the
tests were performed at the same time of the day in all the subjects and at a comfortable environment.
Various tests used for the assessment of sympathetic and parasympathetic activity are as follows:
Standing to lying ratio S/L ratio:
Each subject stand quietly and then lie down without any support while continuous ECG was recorded
from 20 beats before to 60 beats after lying down. The longest R-R interval during 10 beats after lying
down was calculated.
Lying to standing 30:15 S/L ratio:
Each subject was made to lie quietly for 3 minutes then asked to stand up and a continuous ECG was
recorded and 30:15 ratio was calculated by taking the ratio of R-R interval at beat 30 and beat 15 after
standing.
Valsalva Ratio:
Subject was asked to perform the valsalva maneuver for 15 sec. Three trials were performed at interval of
5 min. Continuous ECG was recorded 1 min before to 1 min after the maneuver. The ratio was taken as
maximum R-R interval after maneuver to that of shortest R-R interval during the strain.
Tachycardia Ratio:
Shortest R-R interval during the valsalva maneuver was divided by the longest R-R value before this.
The sympathetic activity was assessed by the
Galvanic skin Resistance (GSR):
The electrodes were applied over the two index fingers and a constant current of 5 micro ampere was
passed through the electrodes. The level of skin resistance was calculated from the recording.
Hand grip test:
Diastolic blood pressure response to static exercise was done in form of this test for one minute and
changes were observed.
Cold pressure Response:
The test was done at the end because of slight unpleasantness associated with the test. Blood pressure of
the subject was recorded under resting condition. Then the subject was asked to immerse his hand in cold
water at 1-4 degree centigrade. BP readings were made from the other arm at 30 Sec. intervals for a
period of two min. The maximum increase in systolic and diastolic BP was determined and results
recorded. For each variable group of autonomic function tests performed in the study mean and standard
deviation of results were calculated.
International Journal of Basic and Applied Medical Sciences ISSN: 2277-2103 (Online)
An Online International Journal Available at http://www.cibtech.org/jms.htm
2011 Vol. 1 (1) September-December, pp.144-148/Kiran et al.
Research Article
146
RESULTS
The data revealed that mean values for the S/L, 30:15 and valsalva ratio are higher in meditators than in
non meditators. The statistics also showed a highly significant value of S/L, 30:15 and valsalva ratio in
meditators (P<0.001). The mean value for tachycardia ratio is higher in non-meditators and is also
statistically highly significant. (P<0.001) This indicates that parasympathetic activity is more in
meditators as compared to non meditators.
Table1. Comparative study of parasympathetic functions in meditators and non- meditators
Parameters
Meditators
Non Meditators
P value
Significance
Mean
S.D.
Mean
S.D.
S/L ratio
1.20
0.10
1.08
0.09
< 0.001
H.S.
30:15 ratio
1.15
0.09
1.09
0.07
< 0.001
H.S.
Valsalva ratio
1.60
0.20
1.33
0.13
< 0.001
H.S.
Tachycardia ratio
0.68
0.11
0.75
0.08
< 0.001
H.S.
S/L = Standing to lying ratio
30:15 = Lying to standing ratio
HS = Highly significant
Table 2. Comparative study of sympathetic functions in meditators and non meditators
Parameters
Mediators
Non Mediators
P value
Significance
Mean
S.D.
Mean
S.D.
Cold Pressor Response
Systolic blood pressure
Diastolic blood pressure
Rise in mm Hg
6.32
6.00
2.41
2.65
13.88
13.66
3.95
3.35
< 0.001
< 0.001
H.S.
H.S.
Hand Grip Test
Systolic blood pressure Diastolic
blood pressure
(Rise in mm Hg)
13.12
11.96
3.57
2.98
20.24
17.20
4.83
3.90
< 0.001
< 0.001
H.S.
H.S.
Galvanic Skin Resistance
(Kohms)
162.52
6.41
155.80
5.70
< 0.001
H.S.
The data obtained on sympathetic function study in meditators and non-meditators revealed that mean
values for rise in blood pressure due to cold pressor response and hand grip test are higher in non-
meditators compared to meditators and the values are statistically highly significant (P<0.001). The mean
value for GSR is higher in meditators than non- meditators and statistically highly significant (P<0.001).
These values of cold pressure response, hand grip test and galvanic skin resistance in mediators showed
that sympathetic activity is low in mediators as compared to non-mediators.
DISCUSSION
Work done over the past few years gives us an indication of studies carried out on meditators for the
autonomic nervous system activity. The data on this aspect was lacking in this part of the country, so the
present study was conducted to measure the autonomic nervous system activity in meditators and
compare it with that of non-meditators using S/L ; 30:15, valsalva ratio and tachycardia ratio for
parasympathetic activity and cold pressor response, hand grip test and galvanic skin resistance for
sympathetic activity. In the present study changes were noticed in some parameters of both sympathetic
and parasympathetic function tests on comparison between meditators and non-meditators.
Parasympathetic function tests revealed that mean value for S/L ratio is lower in non-meditator
(1.08±0.09) compared to meditators (1.20 ± 1.10) and found to be statistically highly significant
International Journal of Basic and Applied Medical Sciences ISSN: 2277-2103 (Online)
An Online International Journal Available at http://www.cibtech.org/jms.htm
2011 Vol. 1 (1) September-December, pp.144-148/Kiran et al.
Research Article
147
(P<0.001). L/s ratio is higher in meditators which is again highly significant statistically
(P<0.001)Valsalva ratio is highly significant (P<0.001) indicating greater parasympathetic activity in
meditators. Tachycardia ratio on statistical analysis shows a highly significant change from non
meditators to meditators (P<0.001). It indicates that parasympathetic activity is more in meditators as
compared to non meditators. The sympathetic function tests revealed that during cold pressure response
mean value for change in systolic and diastolic blood pressures to be 6.32 ± 2.41 and 6 ± 2.65
respectively in meditators as compared to non meditators (13.88 ± 3.95 and 13.66 ± 3.35 respectively).
So, the meditators showed lesser rise of blood pressure as compared to non-meditators which is highly
significant (P<0.001). In any condition where there is low sympathetic activity the cold pressor response
will be expected to show a smaller rise.
During hand grip test the mean value of changes in systolic and diastolic blood pressures in meditators
are 13.12 ± 3.57mmHg and 11.96 ± 2.98 resp while in non meditators20.24 ± 4.83 and 17.20 ± 3.90 resp.
The values are highly significant (P<0.001). The mean value for galvanic skin resistance in meditators is
162.52 ± 6.41 while in non-meditators it is 155.80 ± 5.70 showing marked rise of GSR in meditators
which is highly significant statistically (P<0.001). It thus implies that the mediators have a lower
sympathetic activity compared to non mediators. Our study is consistent with those of Levander (1972),
Kanchan (1973, 1984), Usha Panjwani (1994) . Levander (1972) reported an increase in forearm blood
flow during the practice of transcendental meditation suggesting decreased sympathetic activity and deep
relaxation. Kanchan(1973, 1984) studied changes in the EEG and autonomic parameters of practitioners
of transcendental meditation and Brahma Kumaris Raj Yoga meditation, GSR tended to increase during
meditation sessions. Panjwani (1995) performed a study on the effect of Sahaja Yoga practice on stress
management in patients of epilepsy which showed reduction in stress who practiced Sahaja yoga. A study
by (Goswami 2011) revealed definite and specific changes in the heart rate variability of the subjects
during meditation. The study shows that meditative state has a completely different physiology and that it
can be achieved by any meditation technique. A well-designed electroencephalographic (EEG) study
reported that the experience is consistently associated with symmetrically distributed fronto-parietal
midline alpha/theta activity. Perhaps most remarkable was the strong correlation between subjective
quality of self-reported meditative experience and the strength of these electrical changes Manocha
(2010).
Our study is consistent with Yi-Yuan et al. (2009), Manocha et al. (2010), Madhavi et al. (2010), Mohan.
et al ( 2011 ) , Raghavendra et al ( 2011 ) , Goswami et al. ( 2011 ) , Manocha et al. (2011 ) , Shaoweia at
al. ( 2011 ) . Practice of meditation produced a relaxation response even in the young adult subjects who
had never practiced meditation before. The practice of meditation reduced the physiologic stress
responses without taking away the beneficial effect of stress, namely, improved memory scores Mohan et
al. (2011). From the above discussion we conclude that meditators have lower sympathetic activity and
dominant parasympathetic activity as compared to their non-meditators counterparts.
CONCLUSION
To conclude, meditative lifestyle is specifically associated with better mental health scores. The
autonomic nervous system activity is affected by meditation. While comparing ANS activity of
meditators and non meditators of each group separately, we conclude that there is increase in
parasympathetic activity, but the sympathetic activity was less in meditators.
ACKNOWLEDGEMENTS
Authors are grateful to the staff of Physiology Department, Sri Guru Ram Das Institute, Amritsar for their
kind contribution and support in making this research work possible.
International Journal of Basic and Applied Medical Sciences ISSN: 2277-2103 (Online)
An Online International Journal Available at http://www.cibtech.org/jms.htm
2011 Vol. 1 (1) September-December, pp.144-148/Kiran et al.
Research Article
148
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