Year : 2013 | Volume : 1 | Issue : 2 | Page : 54 - 56  

Original Articles
Effect of Meditation on electro encephalographic graph (EEG), blood pressure, heart rate and respiratory rate

Sundarachari R1, Dhanasree Naidu VK2, Kokiwar PR3, Surendra BV4

1&2Associate Professor of Physiology Malla Reddy Medical College for Women, Hyderabad.

3Professor of Community Medicine, MRIMS, Hyderabad. 4Assistant Professor of Physiology, MNR Medical College, SangaReddy.


Background: Ancient India presented to the world a great solution in the form of Meditation. Meditation is one healthy means which control the brain electrical activity to maintain a good health and healthy society.

Objective: To study the effect of meditation on electro encephalograph and on other parameters like blood pressure, heart rate and respiratory rate.

Methods: Twenty healthy individuals who were practicing meditation regularly since last five years were compared with 20 healthy individuals who never practiced meditation. EEG, blood pressure, heart rate and respiratory rate was recorded on these selected Individuals before and during meditation.

Results: Meditators as a group showed significant increase in Alfa actitivity in occipital region of frequency of 8 Hz and decrease of - activity in parietal region compared to controls. Diastolic blood pressure, heart rate and respiratory rate showed a significant reduction before and during meditation among study subjects compared to controls. But this was not significant in case of systolic blood pressure.

Conclusion: It was found that meditation has a positive impact on the EEG changes and other parameters studied among meditators as compared to non-meditators.

Key Words: Electrical activity, Electo encephalogram, Meditation

Corresponding Author: Dr. Kolusu Natesh, Room no 104, Staff Quarters, Malla Reddy Medical College Campus, Suraram X roads, jeedimetla, Hyderabad. Email :-,


Brain, the vital organ of the body, is organized with and extensive intricate neuronal circuits to control somatic, visceral, and intellectual functions. Researchers have developed spectral analysis and computer models to correlate the physiological and psychological functions of brain with environment. The states of consciousness develop in brain due to the processing of the sensory and extra sensory inputs from the brain. Philosophers, psychologists and neurologists have tried to evolve neuronal network models of nervous system to conclude that consciousness is infact no more than behavior of a vast assembly of nerve cells and their associated molecules. Quantitative analysis of neuronal electrical activity control neuron is one of the parameters to study changes in the Altered State of Consciousness. This can be done with the aid of Electo Encephalogram (EEG). [1]

The modern society imposes tax on intellectual function of brain and enables to cope up the conscious states of man and he suffers from various illnesses. Since ancient ages, conscious mind would be controlled by Yoga and Meditation (Mental health). Sufficient scientific information is available to show that certain types of `Yogabhayasas’ (Practice of Yoga and Meditation) result in the improvement of visceral functions of the body, through their influence on Nervous System. Such results usually follow those yogic practices which have a meditative component. [1]

The linkage between mind & body is widely accepted in ancient wisdom which is now scientifically established. The role of Limbic system of brain in regulating the homeostatic conditions in the body by influencing visceral mechanisms through automatic nervous out flow and endocrine secretions is now well known. These neural Control regions are also involved in the affective (emotional) behaviors of the individual emotional or mental stress.

Involvement of these mechanisms upsets the optional level of Homeostasis. It can, therefore, be easily understood that by properly conditioning these regions of nervous systems, normal Homeostatic conditions can be maintained. The process of mental relaxation can be expected to produce such condition by meditative practices. [2]

With this background we have evaluated brain electrical activity in yogic people and compared the same with controls who never practiced Yoga and Meditation.

Material and Methods

This was a Hospital based Cross sectional study with comparison group. Institutional Ethics Committee Permission was obtained before initiation of the study. The study was conducted at Thirumala Tirupathi Devasthanam (TTD) Hospital, Tirupathi. Permission from Medical Superintendent was obtained to conduct the study.

Selection of study subjects and controls:

A total of 40 individuals were selected for study and they were divided into two groups.

Twenty healthy individuals who were having regular, un-interrupted practice in meditation for more than five years around Tirupathi town were selected. For this purpose, Mediators from yogananda Sastanga Society of India, Spiritual Society, Pyramid Dhyana Meditation, and Rishi Sanskriti Yoga were enrolled as study subjects.

Twenty Equal numbers of Healthy Individuals of same age group who never practiced Yoga and Meditation were enrolled as controls.

Inclusion Criteria:

  1. Study subjects having regular uninterrupted practice of Meditation for more than five years.
  2. Use of Analgesics, Antihistamines occasionally, was not be taken in to considerations while including study subjects and controls.

Exclusion Criteria:

  1. Individuals who were undergoing treatment for chronic ailments like Diabetes Hypertension, Asthma, and Epilepsy.
  2. Individuals not willing to participate in the study.

Recording of EEG and other parameters: EEG was recorded in a room. The room was curtailed from all sounds. Individual were asked to have Head bath with shampoo before recording EEG so that the jelly for E.E.G. applied with lead should exert maximum effect. The study group which consisted of experienced meditators was asked to perform meditation. Whereas the control group individuals were asked to sit as they like with their eyes closed. EEG was recorded before the closure of eyes or meditation started. Second recording of EEG was recorded during the meditation i.e. after 15 minutes of initiation of meditation in case of study subjects and 15 minutes after closure of eyes in case of controls. Other parameters like blood pressure, heart rate and respiratory rate were recorded before and during meditation or sitting in all individuals.

All the recordings i.e. EEG, blood pressure, heart rate and respiratory rate were recorded as the standard guidelines. [3, 4]

Statistical analysis: The data was analyzed using means and standard deviation. The difference between the mean values of study and control group was compared with the help of Student’s‘t’ test. P value less the 0.05 was considered significant.


EEG, blood pressure, heart rate and respiratory rate measurements were compared between study subjects (individuals having practice of meditation for more than five years) and controls (individuals not having any practice of meditation).

Table 1 shows effect of meditation on EEG. Alpha wave frequency was found to be significantly lower among study subjects (meditators) compared to controls (non-meditators) (p = 0.0022). Alpha waves voltage was significantly higher among study subjects as compared to controls (p = 0.0002). Relatively high amplitudes of alpha waves indicate synchronized activity. Increase in alpha activity indicates more wakeful alertness.

Systolic blood pressure (SBP), diastolic blood pressure (DBP), pulse and respiratory rate (RR) were recorded before and during meditation or rest of study subjects and controls respectively. The mean change in these parameters is shown in table 2. It is observed that due to meditation all the parameters i.e. DBP, RR and pulse have reduced significantly among study subjects as compared to controls (p < 0.05). Difference in reduction in SBP was not significant between the two groups (p = 0.3841)


Meditation is engagement in contemplation, especially of spiritual or devotional nature: To elaborate further meditation is an attempt to concentrate mind on a single form, or an idea, or an aspect Divinity at the exclusion of all other forms, thoughts and ideas. The mind is focused in words and this effort of concentration acts as a stimulus to gain access to the knowledge and the object of meditation. The aspirant makes an attempt to minimize perceptions through general and special senses like tough, sight, hearing etc and detaching mind from sense organs in brain. This helps in controlling restlessness of mind in favour of inner contemplation. [5]

The present study was carried on twenty subjects during the states of meditation and the results were compiled and analysed. During the state of meditation most of them showed persistent Alpha activity and increased amplitude wave pattern compared to controls. It was observed that those who had well marked Alpha activity in resting records showed greater amplitude. This observation confirmed the results of study by Kasamatsu A [6] and Anand BK et al [7] who observed a preponderance of alpha waves in E.E.G. of yogis indicating a more relaxed state of mind. Further it was observed that a sensory stimulus such as bud bang, cold or hot stimuli which normally block alpha rhythm could not do so in yogis during meditation. Power spectral Analysis of 24 hour E.E.G. in those practicing Transcendental Meditation has shown increase in alpha activity which indicates reduction in time spent in sleeping and increase in alpha power indicates a more relaxed mind during awake period. Further it was found that there was better balance and synchrony in E.E.G. recorded from left and right of frontal and occipital fields. Decrease frequency of Alpha activity and increase the amplitude during meditation exhibit alert wakefulness which is characteristic of meditation based speed of consciousness.

Our findings confirmed the observations of Kasamatsu and Herai [6] that the changes depend on mental state and experience in meditation. Adey WR, [8] Banquet JP, [9] and Kasamatsu [6] and Joseph S et al [10] showed that people with more meditative experience have decrease alpha frequency and increased alpha voltage and and alert stage indicating that cerebral cortex is very active and metabolic rate is increased by 20% but the person is apparently in a deep sleep: a sleep called paradoxical sleep.

We found that meditation lowers the SBP, DBP, RR and pulse rate. The SBP fell from 133.9+11.6 to 132.9+10.5 and DBP from 86.4 to 83.3. The decline in heart rate is more pronounced in subjects with meditative experience than controls in relaxed state. This indicate that meditation lowers the heart rate more than bio feedback, progressive relaxation, other therapies or simple sitting. Similar findings were observed by Wenger MA et al [11] and Kyere JG et al. [12]

Meditation decreases the resistance in large blood vessles of circulatory system in various parts of the body. It might help relax small blood vessels which in turn reduce the diastolic pressure. Meditation reduces activity in nervous system by parasymphathetic predominance which is responsible for calming. During anxiety and tension states there is rise in the level of lactate in the blood.


There is ample evidence that meditation can reduce hypertension, relive pain, stress, premenstrual syndrome when used in combination with bio-feedback.

The EEG data analysis clearly indicated significant changes observed in increased voltage of Alpha activity as against controls. Individuals with the number of years of more experience in meditation have shown more activity than individuals no experience in meditation. And no- experience spares Alpha activity and more delta activity which showed more relationship of Alpha activity to meditation. The other parameters like blood pressure heart rate and respiratory rate showed significant decrease which indicated psychological, physiological and clinical significance of meditation.


  1. Bijlani RL. The Yogic Practices: Meditation. In: Understanding Medical Physiology, 3rd New Delhi: Jaypee Brothers;2004. p. 890-916.
  2. Chakrabarti BK, Ghosh HN, Sahana SN. Physiological Changes during Meditation. In: Chakrabarti, Ghosh and Sahana’s Human Physiology, 2nd Calcutta: New Book Stall;1984. p. 1236-44.
  3. Guyton AC, Hall JE. Vascular Distensibility, and functions of the arterial and venous systems. In: Textbook of Medical Physiology, 10th Philadelphia: Saunders;2000. p. 152-61.
  4. Guyton AC, Hall JE. States of brain activity – sleep, brain waves; epilepsy; psychoses. In: Textbook of Medical Physiology, 10th Philadelphia: Saunders;2000. p. 152-61.
  5. Fenwick PB, Donaldson S, Gillis L, Bushman J, Fenton GW, Perry I et al. Metabolic and EEG changes during transcendental meditation: an explanation. Biol Psychol. 1977 Jun;5(2):101-18.
  6. Kasamatsu A, Hirai T. An electroencephalographic study on the zen meditation (Zazen). Folia Psychiatr Neurol Jpn. 1966;20(4):315-36.
  7. Anand BK, Chhina GS, Singh B. Some aspects of electroencephalographic studies In Yogis. Electroencephalogr Clin Neurophysiol.1961;13(3):452-6.
  8. Adey WR. Tissue interactions with nonionizing electromagnetic fields. Physiol Rev. 1981 Apr;61(2):435-514.
  9. Banquet JP. Spectral analysis of the EEG in meditation. Electroencephalogr Clin Neurophysiol. 1973 Aug;35(2):143-51.
  10. Joseph S, Sridharan K, Patil SK, Kumaria ML, Selvamurthy W, Joseph NT et al. Study of some physiological and biochemical parameters in subjects undergoing yogic training. Indian J Med Res. 1981 Jul;74:120-4.
  11. WENGER MA, BAGCHI BK. Studies of autonomic functions in practitioners of Yoga in India. Behav Sci. 1961 Oct;6:312-23.
  12. Okyere JG, Ktonas PY, Meyer JS. Quantification of the alpha EEG modulation and its relation to cerebral blood flow. IEEE Trans Biomed Eng. 1986 Jul;33(7):690-6.


Table 1: Comparison of Electroencephalogram (EEG) between study subjects and controls

Type of ECG wave

Study subjects


p value

t value

Alpha wave frequency





Alpha wave voltage





Beta wave frequency





Beta wave voltage





*values are given in mean+SD


Table 2: Comparison of SBP, DBP, PR, and RR between study subjects and controls


Study subjects


p value

t value

SBP reduction





DBP reduction





PR reduction





RR reduction





SBP = systolic blood pressure, DBP = diastolic blood pressure, PR = pulse rate,

RR = respiratory rate

*values are given in mean+SD



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