Difference between revisions of "The science of meditation"
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− | Meditation: Over many millennia, people were aware of the remarkable connection between the mind and the body. Recent scientific research on the effects of meditation on physiology of man has discovered the basic mechanics behind this amazing connection. | + | [[Meditation]]: Over many millennia, [[people]] were {{Wiki|aware}} of the remarkable connection between the [[mind]] and the [[body]]. Recent [[scientific]] research on the effects of [[meditation]] on [[physiology]] of man has discovered the basic mechanics behind this amazing connection. |
− | However, the 'science' of meditation, i.e. understanding how meditation effects the physiology of the meditator and the outcomes of such effects have just begun to take shape thanks to several researchers based mainly in the United States. | + | However, the '[[science]]' of [[meditation]], i.e. [[understanding]] how [[meditation]] effects the [[physiology]] of the [[meditator]] and the outcomes of such effects have just begun to take shape thanks to several researchers based mainly in the [[Wikipedia:United States of America (USA)|United States]]. |
− | Today, over one thousand peer-reviewed scientific research articles published in many prestigious journals are available on this subject. | + | Today, over one thousand peer-reviewed [[scientific]] research articles published in many prestigious journals are available on this [[subject]]. |
[[File:Meditation 2.jpg |thumb|300px|]] | [[File:Meditation 2.jpg |thumb|300px|]] | ||
− | ==Studies on meditation== | + | ==Studies on [[meditation]]== |
− | Many studies have shown that meditation has not only a mental effect but also wide ranging and profound physiological effects. In this article, key physiological effects of meditation and the mechanism of action behind such effects are briefly summarized. | + | Many studies have shown that [[meditation]] has not only a [[mental]] effect but also wide ranging and profound [[physiological]] effects. In this article, key [[physiological]] effects of [[meditation]] and the {{Wiki|mechanism}} of [[action]] behind such effects are briefly summarized. |
− | For in-depth information on the subject, several excellent monographs and a large number of research papers are available. These can be easily located using an internet search engine with a phrase such as 'meditation physiology' or 'science of meditation'. | + | For in-depth [[information]] on the [[subject]], several {{Wiki|excellent}} {{Wiki|monographs}} and a large number of research papers are available. These can be easily located using an internet search engine with a [[phrase]] such as '[[meditation]] [[physiology]]' or '[[science]] of [[meditation]]'. |
− | Such recent searches have resulted in over 1,800,000 citations, over 1000 of which are scientific research publications. | + | Such recent searches have resulted in over 1,800,000 citations, over 1000 of which are [[scientific]] research publications. |
− | In his pioneering work on the physiological effects of meditation, Dr. Herbert Benson of the Harvard Medical School, in 1971 published the results of his first study on meditation followed by the multi-year national bestseller monograph, The Relaxation Response, in 1975. | + | In his pioneering work on the [[physiological]] effects of [[meditation]], Dr. {{Wiki|Herbert Benson}} of the [[Harvard Medical School]], in 1971 published the results of his first study on [[meditation]] followed by the multi-year national bestseller {{Wiki|monograph}}, The [[Relaxation]] Response, in 1975. |
− | It is a resounding testament to Dr. Benson's revolutionary insight about the 'fight or flight response versus the relaxation response' that this groundbreaking monograph is still available as a mass market paperback even after 35 years of initial publication. | + | It is a resounding testament to Dr. Benson's {{Wiki|revolutionary}} [[insight]] about the 'fight or flight response versus the [[relaxation]] response' that this groundbreaking {{Wiki|monograph}} is still available as a {{Wiki|mass}} market paperback even after 35 years of initial publication. |
− | Dr. Benson was the first to suggest that the cause for societal stress that we all experience from time to time in varying amounts is the result of our inability to react to the stressful situations in the way our bodies are programmed naturally during human evolution. | + | Dr. Benson was the first to suggest that the [[cause]] for societal [[stress]] that we all [[experience]] from time to time in varying amounts is the result of our inability to react to the stressful situations in the way our bodies are programmed naturally during {{Wiki|human evolution}}. |
− | For millions of years, as creatures living in forests, our ancient ancestors reacted to threatening situations in one of two ways. If the threat was deemed manageable, they evoked the 'fight' response and fought off the threat. If the situation was deemed hopeless, they ran for their lives invoking the 'flight' response. However, once we began to become more and more 'civilized' neither of these responses became viable options. | + | For millions of years, as creatures living in forests, our [[ancient]] {{Wiki|ancestors}} reacted to threatening situations in one of two ways. If the threat was deemed manageable, they evoked the 'fight' response and fought off the threat. If the situation was deemed hopeless, they ran for their [[lives]] invoking the 'flight' response. However, once we began to become more and more 'civilized' neither of these responses became viable options. |
==The fight or flight reflexes== | ==The fight or flight reflexes== | ||
− | The fight or flight reflexes prepare the body for survival action using the responses given on the left column in the table below. However, modern man being unable to use up the physiological energy created this way by our natural instincts, had to learn to cope with the civilized norms and not respond to the stressful situations as the nature had intended us to do. | + | The fight or flight reflexes prepare the [[body]] for survival [[action]] using the responses given on the left column in the table below. However, {{Wiki|modern}} man being unable to use up the [[physiological]] [[energy]] created this way by our natural {{Wiki|instincts}}, had to learn to cope with the civilized norms and not respond to the stressful situations as the [[nature]] had intended us to do. |
− | The result of this is the stress that we all experience. However, Dr. Benson pointed out that our bodies are capable of evoking another response to curb the effects of the fight or flight response. He named this 'the relaxation response'. | + | The result of this is the [[stress]] that we all [[experience]]. However, Dr. Benson pointed out that our bodies are capable of evoking another response to curb the effects of the fight or flight response. He named this 'the [[relaxation]] response'. |
− | The principal difference between the two responses is that the fight or flight response is automatic and the relaxation response needs to be consciously evoked. Meditation is the technique for evoking the relaxation response which bring about the results shown in the right column in the table above. | + | The [[principal]] difference between the two responses is that the fight or flight response is automatic and the [[relaxation]] response needs to be [[consciously]] evoked. [[Meditation]] is the technique for evoking the [[relaxation]] response which bring about the results shown in the right column in the table above. |
− | Our bodies respond to meditation through three physiological systems; | + | Our [[bodies]] respond to [[meditation]] through three [[physiological]] systems; |
<poem> | <poem> | ||
− | :::1. Autonomic Nervous System, | + | :::1. Autonomic {{Wiki|Nervous System}}, |
:::2. Endocrine System and, | :::2. Endocrine System and, | ||
:::3. Musculature System. | :::3. Musculature System. | ||
</poem> | </poem> | ||
− | These systems are very tightly interconnected and therefore interdependent. The chemical changes resulting in one system often has a cascading effect over the other systems. | + | These systems are very tightly interconnected and therefore [[interdependent]]. The chemical changes resulting in one system often has a cascading effect over the other systems. |
− | The autonomic nervous system controls the body parts which function automatically. It has two branches; the sympathetic nervous system which increases arousal when the body is under threat. | + | The autonomic {{Wiki|nervous system}} controls the [[body]] parts which function automatically. It has two branches; the sympathetic {{Wiki|nervous system}} which increases arousal when the [[body]] is under threat. |
− | The effect of this system is the 'fight or flight response' which is characterized by increase in heart rate, blood pressure, breathing rate, sweating, blood glucose, blood flow to muscles, alertness etc. The other, the parasympathetic nervous system, is responsible for restoring the body to a relaxed state. | + | The effect of this system is the 'fight or flight response' which is characterized by increase in [[heart]] rate, {{Wiki|blood pressure}}, [[breathing]] rate, sweating, {{Wiki|blood}} glucose, {{Wiki|blood}} flow to {{Wiki|muscles}}, [[alertness]] etc. The other, the parasympathetic {{Wiki|nervous system}}, is responsible for restoring the [[body]] to a [[relaxed]] [[state]]. |
− | In simple terms it can be stated that the sympathetic system is designed to handle the stressful situations and the parasympathetic system to return the body to its natural (relaxed) state. | + | In simple terms it can be stated that the sympathetic system is designed to handle the stressful situations and the parasympathetic system to return the [[body]] to its natural ([[relaxed]]) [[state]]. |
− | ==The endocrine system== | + | ==The {{Wiki|endocrine system}}== |
− | To study what part of the brain is effected by meditation, researchers at the Harvard Medical School used MRI technology to monitor activity of the brain while the subjects meditated. | + | To study what part of the {{Wiki|brain}} is effected by [[meditation]], researchers at the [[Harvard Medical School]] used {{Wiki|MRI}} technology to monitor [[activity]] of the {{Wiki|brain}} while the [[subjects]] [[meditated]]. |
− | They observed that meditation stimulated the sections of the brain in charge of the autonomic functions such as digestion, blood pressure regulation etc. The endocrine system releases hormones which modify the action of the organs in response to the signals from the autonomic system. | + | They observed that [[meditation]] stimulated the [[sections]] of the {{Wiki|brain}} in charge of the autonomic functions such as {{Wiki|digestion}}, {{Wiki|blood pressure}} regulation etc. The {{Wiki|endocrine system}} releases {{Wiki|hormones}} which modify the [[action]] of the {{Wiki|organs}} in response to the signals from the autonomic system. |
− | The main organ of this system is the Adrenal gland situated above the kidneys. The adrenal gland produces the hormones adrenaline, noradrenaline and cortisol. These three are responsible for preparing the body for survival by invoking the appropriate response to any stressful situation at hand. | + | The main {{Wiki|organ}} of this system is the Adrenal gland situated above the [[kidneys]]. The adrenal gland produces the {{Wiki|hormones}} {{Wiki|adrenaline}}, {{Wiki|noradrenaline}} and cortisol. These three are responsible for preparing the [[body]] for survival by invoking the appropriate response to any stressful situation at hand. |
− | Most of the other endocrine hormones are produced in the brain, particularly in the hypothalamus. These are associated with changes in the mood, pain threshold, immune system activity and the tone of smooth muscles (the muscles of the organs). | + | Most of the other {{Wiki|endocrine}} {{Wiki|hormones}} are produced in the {{Wiki|brain}}, particularly in the [[hypothalamus]]. These are associated with changes in the [[mood]], [[pain]] threshold, {{Wiki|immune system}} [[activity]] and the tone of smooth {{Wiki|muscles}} (the {{Wiki|muscles}} of the {{Wiki|organs}}). |
− | The musculature system consists of skeletal muscles (the muscles connected to the bones) and smooth muscles (the muscles of the organs). The skeletal muscles are voluntary (work as commanded by the brain) where as the smooth muscles are autonomous (work involuntarily). | + | The musculature system consists of skeletal {{Wiki|muscles}} (the {{Wiki|muscles}} connected to the [[bones]]) and smooth {{Wiki|muscles}} (the {{Wiki|muscles}} of the {{Wiki|organs}}). The skeletal {{Wiki|muscles}} are voluntary (work as commanded by the {{Wiki|brain}}) where as the smooth {{Wiki|muscles}} are autonomous (work involuntarily). |
− | All types of meditation effect all three above systems although in varying degrees. Most early research work had been done on Concentration Meditation, particularly Transcendental Meditation (TM) and Breathing Meditation (anapana). | + | All types of [[meditation]] effect all three above systems although in varying degrees. Most early research work had been done on [[Concentration Meditation]], particularly [[Transcendental Meditation]] (TM) and [[Breathing Meditation]] ([[anapana]]). |
− | However, more recently, publications are beginning to appear on Insight Meditation (vipassana) as well. | + | However, more recently, publications are beginning to appear on [[Insight Meditation]] ([[vipassana]]) as well. |
− | ==Control of breathing== | + | ==Control of [[breathing]]== |
− | One principal mode of physiological effect of meditation appears to stem from the control of breathing. Respiration is directly linked with the autonomic nervous system. | + | One [[principal]] mode of [[physiological]] effect of [[meditation]] appears to stem from the control of [[breathing]]. Respiration is directly linked with the autonomic {{Wiki|nervous system}}. |
− | Chemical receptors in the walls of aorta (central conduit from the heart to the body) and carotid arteries (main arteries in the neck that supply blood to the brain) help to control breathing and are sensitive to changes of the amount of carbon dioxide (CO2) circulating in the blood. | + | Chemical {{Wiki|receptors}} in the walls of {{Wiki|aorta}} (central conduit from the [[heart]] to the [[body]]) and carotid {{Wiki|arteries}} (main {{Wiki|arteries}} in the neck that supply {{Wiki|blood}} to the {{Wiki|brain}}) help to control [[breathing]] and are [[sensitive]] to changes of the amount of {{Wiki|carbon}} dioxide (CO2) circulating in the {{Wiki|blood}}. |
− | Over-breathing results in lower CO2 concentration while under-breathing leads to a build up of CO2 in blood. Mildly higher CO2 levels result in para-sympathetic dominance (relaxation) while severely higher CO2 levels result in sympathetic dominance (fight-flight response). | + | Over-breathing results in lower CO2 [[concentration]] while under-breathing leads to a build up of CO2 in {{Wiki|blood}}. Mildly higher CO2 levels result in para-sympathetic dominance ([[relaxation]]) while severely higher CO2 levels result in sympathetic dominance (fight-flight response). |
− | Shallow and controlled breathing in meditation causes mildly high CO2 levels and activates the parasympathetic system which leads to a feeling of relaxation with decreasing in heart rate, blood pressure, blood coagulation time and acuity of senses. | + | Shallow and controlled [[breathing]] in [[meditation]] [[causes]] mildly high CO2 levels and activates the parasympathetic system which leads to a [[feeling]] of [[relaxation]] with {{Wiki|decreasing}} in [[heart]] rate, {{Wiki|blood pressure}}, {{Wiki|blood}} coagulation time and acuity of [[senses]]. |
− | These effects are the result of reduction of the so called 'stress hormones' adrenaline, cortisol etc. and the increase of endorphins or the feel good hormones facilitated by the endocrine system as mentioned above. | + | These effects are the result of reduction of the so called '[[stress]] {{Wiki|hormones}}' {{Wiki|adrenaline}}, cortisol etc. and the increase of {{Wiki|endorphins}} or the [[feel]] good {{Wiki|hormones}} facilitated by the {{Wiki|endocrine system}} as mentioned above. |
− | A recent medical invention uses the above hypothesis to reduce high blood pressure simply by controlling the rate of breathing. A US FDA approved electronic apparatus called RESPeRATE(r) utilizes patented technology to deliver certain kinds of breathing exercises. | + | A recent {{Wiki|medical}} invention uses the above {{Wiki|hypothesis}} to reduce high {{Wiki|blood pressure}} simply by controlling the rate of [[breathing]]. A US FDA approved electronic apparatus called RESPeRATE(r) utilizes patented technology to deliver certain kinds of [[breathing]] exercises. |
− | It is nothing more than a 'walkman' type listening devise which commands the listener to breath in and out on cue. When these exercises are performed for as little as 15 minutes a day, 3-4 times a week, they have been shown to significantly lower blood pressure with no side effects. | + | It is nothing more than a 'walkman' type listening devise which commands the listener to [[breath]] in and out on cue. When these exercises are performed for as little as 15 minutes a day, 3-4 times a [[week]], they have been shown to significantly lower {{Wiki|blood pressure}} with no side effects. |
− | RESPeRATE(r), available for purchase for about US$ 300 from www.bio-medical.com, utilizes a patented technology to pace breathing from the normal range of 14 to 19 breaths per minute to the "therapeutic zone" of under 10 breaths per minute. The same reduction of blood pressure could be simply achieved via meditation as mentioned above due to the slowing of the rate of breathing. | + | RESPeRATE(r), available for purchase for about US$ 300 from www.bio-medical.com, utilizes a patented technology to pace [[breathing]] from the normal range of 14 to 19 breaths per minute to the "{{Wiki|therapeutic}} zone" of under 10 breaths per minute. The same reduction of {{Wiki|blood pressure}} could be simply achieved via [[meditation]] as mentioned above due to the slowing of the rate of [[breathing]]. |
− | Furthermore, studies of the brain using electroencephalography (EEG) during deep meditation have revealed a slowing and synchronization of brain waves with alpha waves predominating. Emotional tension is known to severely curtail the alpha waves. | + | Furthermore, studies of the {{Wiki|brain}} using {{Wiki|electroencephalography}} ({{Wiki|EEG}}) during deep [[meditation]] have revealed a slowing and synchronization of {{Wiki|brain}} waves with alpha waves predominating. [[Emotional]] tension is known to severely curtail the alpha waves. |
− | Another type of brain activity called the theta wave, which is practically non existent in chronically stressed states, begin to emerge as the meditator enters into a deeper level of concentration. Alpha state of the brain is most conducive to creativity and to assimilation of new concepts while the theta state capable of producing deep insight and intuition. | + | Another type of {{Wiki|brain}} [[activity]] called the theta wave, which is practically non [[existent]] in chronically stressed states, begin to emerge as the [[meditator]] enters into a deeper level of [[concentration]]. Alpha [[state]] of the {{Wiki|brain}} is most conducive to {{Wiki|creativity}} and to assimilation of new [[Wikipedia:concept|concepts]] while the theta [[state]] capable of producing deep [[insight]] and {{Wiki|intuition}}. |
− | It is significant to note that increased alpha and theta activity of the brain continues to exhibit for some time even after the meditation session has ended. | + | It is significant to note that increased alpha and theta [[activity]] of the {{Wiki|brain}} continues to exhibit for some time even after the [[meditation]] session has ended. |
− | Studies comparing different types of breathing during meditation have concluded that deep diaphragmatic (abdominal) breathing was associated with higher EEG alpha response. Thoracic (chest) breathing on the other hand produced weaker alpha response. | + | Studies comparing different types of [[breathing]] during [[meditation]] have concluded that deep diaphragmatic (abdominal) [[breathing]] was associated with higher {{Wiki|EEG}} alpha response. Thoracic ({{Wiki|chest}}) [[breathing]] on the other hand produced weaker alpha response. |
− | ==Abdominal breathing== | + | ==Abdominal [[breathing]]== |
− | Abdominal breathing in which the diaphragm moves up and down in concert with exhaling and inhaling respectively, is also known as 'Yogic Breathing' since this practice was used by Yogis in India over many centuries. | + | Abdominal [[breathing]] in which the {{Wiki|diaphragm}} moves up and down in concert with exhaling and inhaling respectively, is also known as '[[Yogic]] [[Breathing]]' since this practice was used by [[Yogis]] in [[India]] over many centuries. |
− | A popular public health web-site, WebMD, reported that follow up of several studies which began in the '80s have revealed significant cardiac and cancer benefits among groups of meditators compared to control group of non-meditators. | + | A popular public [[health]] web-site, WebMD, reported that follow up of several studies which began in the '80s have revealed significant cardiac and {{Wiki|cancer}} benefits among groups of [[meditators]] compared to control group of non-meditators. |
− | The results reported were quite amazing to say the least. Overall, the meditators were 23% less likely to die of heart disease and stroke. The effect of meditation on hypertension was far more pronounced than all non-drug treatments such as salt restriction, exercise and weight loss. | + | The results reported were quite amazing to say the least. Overall, the [[meditators]] were 23% less likely to [[die]] of [[heart]] {{Wiki|disease}} and stroke. The effect of [[meditation]] on hypertension was far more pronounced than all non-drug treatments such as [[salt]] restriction, exercise and {{Wiki|weight}} loss. |
− | During meditation the concentration of stress hormones such as adrenalin and cortisol in blood goes down. Cortisol is one of the key stress hormones. Consistently high levels of Cortisol in blood result in a long list of physical ailments. | + | During [[meditation]] the [[concentration]] of [[stress]] {{Wiki|hormones}} such as adrenalin and cortisol in {{Wiki|blood}} goes down. Cortisol is one of the key [[stress]] {{Wiki|hormones}}. Consistently high levels of Cortisol in {{Wiki|blood}} result in a long list of [[physical]] {{Wiki|ailments}}. |
− | Another hormone produced in the brain, CRF (Corticotrophin Releasing Factor) is the regulator of Cortisol production. Excess CRF in brain tissue is linked to depression and mood swings. | + | Another {{Wiki|hormone}} produced in the {{Wiki|brain}}, CRF (Corticotrophin Releasing Factor) is the regulator of Cortisol production. Excess CRF in {{Wiki|brain tissue}} is linked to {{Wiki|depression}} and [[mood]] swings. |
− | ==Fast drop in lactate concentration== | + | ==Fast drop in lactate [[concentration]]== |
− | High levels of Cortisol makes the body crave for fatty food. The excess fat intake is stored in the abdominal area and the resulting abdominal obesity is a leading cause for type 2 diabetes, high blood pressure and heart disease. | + | High levels of Cortisol makes the [[body]] [[crave]] for fatty [[food]]. The excess fat intake is stored in the abdominal area and the resulting abdominal obesity is a leading [[cause]] for type 2 diabetes, high {{Wiki|blood pressure}} and [[heart]] {{Wiki|disease}}. |
− | Another blood chemical significantly effected by meditation is Lactate. Lactate is a byproduct of sugar and starch metabolism. Higher Lactate concentration in blood produces feeling of anxiety. Studies have shown up to four times as fast drop in Lactate concentration in meditators compared to subjects resting while lying down. | + | Another {{Wiki|blood}} chemical significantly effected by [[meditation]] is Lactate. Lactate is a byproduct of sugar and starch [[metabolism]]. Higher Lactate [[concentration]] in {{Wiki|blood}} produces [[feeling]] of [[anxiety]]. Studies have shown up to four times as fast drop in Lactate [[concentration]] in [[meditators]] compared to [[subjects]] resting while {{Wiki|lying}} down. |
− | During meditation, blood flow to the brain increases while less blood is circulated to the rest of the body. Another blood chemical Arginine vasopressin (AVP), a beneficial compound in retaining mental alertness, have been measured up to four times the normal levels in meditators compared to control groups. AVP in synthetic form is routinely prescribed to patients with severe mental dullness due to old age. | + | During [[meditation]], {{Wiki|blood}} flow to the {{Wiki|brain}} increases while less {{Wiki|blood}} is circulated to the rest of the [[body]]. Another {{Wiki|blood}} chemical Arginine vasopressin (AVP), a beneficial compound in retaining [[mental]] [[alertness]], have been measured up to four times the normal levels in [[meditators]] compared to control groups. AVP in {{Wiki|synthetic}} [[form]] is routinely prescribed to patients with severe [[mental dullness]] due to [[old age]]. |
− | In essence, modern science has uncovered the reasons behind the well known phenomenon 'the mind-body connection'. It can be stated in simple terms that when practised regularly over a period of time, meditation can produce profound physiological effects. | + | In [[essence]], {{Wiki|modern science}} has uncovered the [[reasons]] behind the well known [[phenomenon]] 'the mind-body connection'. It can be stated in simple terms that when practised regularly over a period of time, [[meditation]] can produce profound [[physiological]] effects. |
− | It is quite satisfying to see that this age old technique has finally undergone extensive scientific scrutiny. The conclusions on the physiological benefits have been remarkable and the cascade of chemical processes uncovered in the studies are amazingly complex and intricate. | + | It is quite satisfying to see that this age old technique has finally undergone extensive [[scientific]] {{Wiki|scrutiny}}. The conclusions on the [[physiological]] benefits have been remarkable and the cascade of chemical {{Wiki|processes}} uncovered in the studies are amazingly complex and intricate. |
− | The writer hold a B.Sc. degree in Chemistry from the University of Peradeniya, Sri Lanka and, M.Sc. and Ph.D. degrees from the University of British Columbia, Canada. | + | The writer hold a B.Sc. [[degree]] in {{Wiki|Chemistry}} from the {{Wiki|University of Peradeniya}}, [[Sri Lanka]] and, M.Sc. and {{Wiki|Ph.D.}} degrees from the {{Wiki|University}} of [[British Columbia]], [[Canada]]. |
− | When not engaged in his professional field of Analytical Chemistry, his interests lie in the fields of Future of Religion and the Interaction Between Religion and Science. | + | When not engaged in his professional field of Analytical {{Wiki|Chemistry}}, his interests lie in the fields of Future of [[Religion]] and the Interaction Between [[Religion and Science]]. |
+ | {{R}} | ||
+ | [http://www.lakehouse.lk/mihintalava/medit02.htm lakehouse.lk] | ||
+ | [[Category:Meditation]] |
Latest revision as of 07:40, 28 February 2016
Meditation: Over many millennia, people were aware of the remarkable connection between the mind and the body. Recent scientific research on the effects of meditation on physiology of man has discovered the basic mechanics behind this amazing connection.
However, the 'science' of meditation, i.e. understanding how meditation effects the physiology of the meditator and the outcomes of such effects have just begun to take shape thanks to several researchers based mainly in the United States. Today, over one thousand peer-reviewed scientific research articles published in many prestigious journals are available on this subject.
Studies on meditation
Many studies have shown that meditation has not only a mental effect but also wide ranging and profound physiological effects. In this article, key physiological effects of meditation and the mechanism of action behind such effects are briefly summarized.
For in-depth information on the subject, several excellent monographs and a large number of research papers are available. These can be easily located using an internet search engine with a phrase such as 'meditation physiology' or 'science of meditation'.
Such recent searches have resulted in over 1,800,000 citations, over 1000 of which are scientific research publications. In his pioneering work on the physiological effects of meditation, Dr. Herbert Benson of the Harvard Medical School, in 1971 published the results of his first study on meditation followed by the multi-year national bestseller monograph, The Relaxation Response, in 1975.
It is a resounding testament to Dr. Benson's revolutionary insight about the 'fight or flight response versus the relaxation response' that this groundbreaking monograph is still available as a mass market paperback even after 35 years of initial publication.
Dr. Benson was the first to suggest that the cause for societal stress that we all experience from time to time in varying amounts is the result of our inability to react to the stressful situations in the way our bodies are programmed naturally during human evolution.
For millions of years, as creatures living in forests, our ancient ancestors reacted to threatening situations in one of two ways. If the threat was deemed manageable, they evoked the 'fight' response and fought off the threat. If the situation was deemed hopeless, they ran for their lives invoking the 'flight' response. However, once we began to become more and more 'civilized' neither of these responses became viable options.
The fight or flight reflexes
The fight or flight reflexes prepare the body for survival action using the responses given on the left column in the table below. However, modern man being unable to use up the physiological energy created this way by our natural instincts, had to learn to cope with the civilized norms and not respond to the stressful situations as the nature had intended us to do. The result of this is the stress that we all experience. However, Dr. Benson pointed out that our bodies are capable of evoking another response to curb the effects of the fight or flight response. He named this 'the relaxation response'. The principal difference between the two responses is that the fight or flight response is automatic and the relaxation response needs to be consciously evoked. Meditation is the technique for evoking the relaxation response which bring about the results shown in the right column in the table above.
Our bodies respond to meditation through three physiological systems;
1. Autonomic Nervous System,
2. Endocrine System and,
3. Musculature System.
These systems are very tightly interconnected and therefore interdependent. The chemical changes resulting in one system often has a cascading effect over the other systems.
The autonomic nervous system controls the body parts which function automatically. It has two branches; the sympathetic nervous system which increases arousal when the body is under threat. The effect of this system is the 'fight or flight response' which is characterized by increase in heart rate, blood pressure, breathing rate, sweating, blood glucose, blood flow to muscles, alertness etc. The other, the parasympathetic nervous system, is responsible for restoring the body to a relaxed state.
In simple terms it can be stated that the sympathetic system is designed to handle the stressful situations and the parasympathetic system to return the body to its natural (relaxed) state.
The endocrine system
To study what part of the brain is effected by meditation, researchers at the Harvard Medical School used MRI technology to monitor activity of the brain while the subjects meditated.
They observed that meditation stimulated the sections of the brain in charge of the autonomic functions such as digestion, blood pressure regulation etc. The endocrine system releases hormones which modify the action of the organs in response to the signals from the autonomic system. The main organ of this system is the Adrenal gland situated above the kidneys. The adrenal gland produces the hormones adrenaline, noradrenaline and cortisol. These three are responsible for preparing the body for survival by invoking the appropriate response to any stressful situation at hand.
Most of the other endocrine hormones are produced in the brain, particularly in the hypothalamus. These are associated with changes in the mood, pain threshold, immune system activity and the tone of smooth muscles (the muscles of the organs). The musculature system consists of skeletal muscles (the muscles connected to the bones) and smooth muscles (the muscles of the organs). The skeletal muscles are voluntary (work as commanded by the brain) where as the smooth muscles are autonomous (work involuntarily).
All types of meditation effect all three above systems although in varying degrees. Most early research work had been done on Concentration Meditation, particularly Transcendental Meditation (TM) and Breathing Meditation (anapana). However, more recently, publications are beginning to appear on Insight Meditation (vipassana) as well.
Control of breathing
One principal mode of physiological effect of meditation appears to stem from the control of breathing. Respiration is directly linked with the autonomic nervous system. Chemical receptors in the walls of aorta (central conduit from the heart to the body) and carotid arteries (main arteries in the neck that supply blood to the brain) help to control breathing and are sensitive to changes of the amount of carbon dioxide (CO2) circulating in the blood.
Over-breathing results in lower CO2 concentration while under-breathing leads to a build up of CO2 in blood. Mildly higher CO2 levels result in para-sympathetic dominance (relaxation) while severely higher CO2 levels result in sympathetic dominance (fight-flight response).
Shallow and controlled breathing in meditation causes mildly high CO2 levels and activates the parasympathetic system which leads to a feeling of relaxation with decreasing in heart rate, blood pressure, blood coagulation time and acuity of senses. These effects are the result of reduction of the so called 'stress hormones' adrenaline, cortisol etc. and the increase of endorphins or the feel good hormones facilitated by the endocrine system as mentioned above. A recent medical invention uses the above hypothesis to reduce high blood pressure simply by controlling the rate of breathing. A US FDA approved electronic apparatus called RESPeRATE(r) utilizes patented technology to deliver certain kinds of breathing exercises. It is nothing more than a 'walkman' type listening devise which commands the listener to breath in and out on cue. When these exercises are performed for as little as 15 minutes a day, 3-4 times a week, they have been shown to significantly lower blood pressure with no side effects.
RESPeRATE(r), available for purchase for about US$ 300 from www.bio-medical.com, utilizes a patented technology to pace breathing from the normal range of 14 to 19 breaths per minute to the "therapeutic zone" of under 10 breaths per minute. The same reduction of blood pressure could be simply achieved via meditation as mentioned above due to the slowing of the rate of breathing.
Furthermore, studies of the brain using electroencephalography (EEG) during deep meditation have revealed a slowing and synchronization of brain waves with alpha waves predominating. Emotional tension is known to severely curtail the alpha waves. Another type of brain activity called the theta wave, which is practically non existent in chronically stressed states, begin to emerge as the meditator enters into a deeper level of concentration. Alpha state of the brain is most conducive to creativity and to assimilation of new concepts while the theta state capable of producing deep insight and intuition. It is significant to note that increased alpha and theta activity of the brain continues to exhibit for some time even after the meditation session has ended.
Studies comparing different types of breathing during meditation have concluded that deep diaphragmatic (abdominal) breathing was associated with higher EEG alpha response. Thoracic (chest) breathing on the other hand produced weaker alpha response.
Abdominal breathing
Abdominal breathing in which the diaphragm moves up and down in concert with exhaling and inhaling respectively, is also known as 'Yogic Breathing' since this practice was used by Yogis in India over many centuries. A popular public health web-site, WebMD, reported that follow up of several studies which began in the '80s have revealed significant cardiac and cancer benefits among groups of meditators compared to control group of non-meditators. The results reported were quite amazing to say the least. Overall, the meditators were 23% less likely to die of heart disease and stroke. The effect of meditation on hypertension was far more pronounced than all non-drug treatments such as salt restriction, exercise and weight loss.
During meditation the concentration of stress hormones such as adrenalin and cortisol in blood goes down. Cortisol is one of the key stress hormones. Consistently high levels of Cortisol in blood result in a long list of physical ailments. Another hormone produced in the brain, CRF (Corticotrophin Releasing Factor) is the regulator of Cortisol production. Excess CRF in brain tissue is linked to depression and mood swings.
Fast drop in lactate concentration
High levels of Cortisol makes the body crave for fatty food. The excess fat intake is stored in the abdominal area and the resulting abdominal obesity is a leading cause for type 2 diabetes, high blood pressure and heart disease. Another blood chemical significantly effected by meditation is Lactate. Lactate is a byproduct of sugar and starch metabolism. Higher Lactate concentration in blood produces feeling of anxiety. Studies have shown up to four times as fast drop in Lactate concentration in meditators compared to subjects resting while lying down.
During meditation, blood flow to the brain increases while less blood is circulated to the rest of the body. Another blood chemical Arginine vasopressin (AVP), a beneficial compound in retaining mental alertness, have been measured up to four times the normal levels in meditators compared to control groups. AVP in synthetic form is routinely prescribed to patients with severe mental dullness due to old age.
In essence, modern science has uncovered the reasons behind the well known phenomenon 'the mind-body connection'. It can be stated in simple terms that when practised regularly over a period of time, meditation can produce profound physiological effects.
It is quite satisfying to see that this age old technique has finally undergone extensive scientific scrutiny. The conclusions on the physiological benefits have been remarkable and the cascade of chemical processes uncovered in the studies are amazingly complex and intricate.
The writer hold a B.Sc. degree in Chemistry from the University of Peradeniya, Sri Lanka and, M.Sc. and Ph.D. degrees from the University of British Columbia, Canada.
When not engaged in his professional field of Analytical Chemistry, his interests lie in the fields of Future of Religion and the Interaction Between Religion and Science.