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

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

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

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

(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

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).

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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