The way meditation works in our physical body: Physiology
There are two organs that play an important role for the effects observed during and after meditation: the brain – including the brain stem- and the heart. The two important areas of the brain that feature prominently in meditation are the frontal lobes, especially the pre-frontal lobe (area of the forehead above the eyebrows) and the limbic system (deep in the centre of the brain). The pre-frontal lobe is the most evolved part of the human brain. Its left side gives us the ability to experience human happiness and enjoyment in life. The pre-frontal lobe is also responsible for other important positive human qualities such us idealism, joy, ability to concentrate, creativity and ability to think abstractly. The limbic system is associated with survival instincts and emotions (amygdala) and the memory (hippocampus) (see figure 1).
The frontal lobes and the limbic system act as a tandem in meditation. While the frontal cortex interprets the nature of the event (i.e. positive or negative) the limbic systems qualifies it as an emotion (positive or negative). In meditation the interconnection between the left pre-frontal lobe and the limbic system increases the production of a positive feeling. It was possible to show the amygdala shrinking in meditators, thus decreasing stress feelings (1). Nevertheless it seems that meditation does not trigger the activation of a single brain area only. It triggers a whole network, or even multiple networks, of areas, both on the surface of the brain and deep inside it, working together then in order to produce the experience of meditation with its behavioral and physical consequences (2).
The heart is the other organ that plays a big role during meditation (3,4,5). The heart has an intrinsic nervous system which acts independently from the brain. It is called “the brain of the heart”. Additionally, the heart relates with all the organs of the body being an integrator and communicator of the body information. It is also able to process the sensorial information arriving from an organ (through its sympathetic and parasympathetic nervous system) and to influence the answer to that organ. The heart communicates with the brain in four ways: a) biophysically, through pressure waves; b) neurologically, through nervous impulses; c) biochemically, through hormones and neurotransmitters ; d) energetically, through its electromagnetic fields. The biophysical communication is mediated by the autonomous nervous system, with its sympathetic (i.e. increase in cardiac frequency) and parasympathetic (i.e. decrease in cardiac frequency) functions. When a person experiments positive emotions, or is in a state of calm, the cardiac rhythm pattern (i.e. pressure in arteries over time) becomes ordered and with sinusoidal waves in a cardiac frequency of 0,1 Hz. In a coherence state, there is a more efficient interaction between the parasympathetic and sympathetic branches of the autonomous nervous system, with an increase of the parasympathetic activity. In this coherent state, synchronization with the brain concerning activity and information occurs. It has to be mentioned that while in the state of relaxation there is a decrease in the cardiac frequency, but a state of coherence needs a coherence rhythm only (which can be of a high or low cardiac frequency).
There is also a neurological communication between the heart and the brain. As mentioned before, the heart has its own nervous systems. The “brain of the heart” has 40,000 neurons. These neurons receive chemical, hormonal, cardiac frequency and rhythm information which are transformed into neurological impulses that are sent to the brain (e.g. pain). These impulses enter into the brain through the brain stem via the spinal medulla. The impulses go to the limbic system, affecting directly the activity of the amygdala; and from here, through the “fronto-limbic loops”, they go to the frontal cortex, which finally influences our experience and behavior. The number of connections from the heart (emotional center) to the brain (cognitive center) is greater than the number of connections in the opposite direction, this explains the tremendous power of emotions. Therefore, when a state of heart coherence is achieved, it will affect the brain bringing it to the same phase. In other words synchronization between heart and brain will occur. The greater the coherence and the synchronicity, the more well-arranged and efficient the nervous, cardiovascular, hormonal and immunity systems will function. When this happens, the body enters into what is called “State of Psychophysiologic Coherence” characterized by a cardiac rhythm being highly coherent (rhythmic pattern of sinusoidal waves), increased parasympathetic activity, and increased synchronicity and entrainment (i.e. same frequency) among physiological systems (e.g. heart and breathing). In this state one is when the beneficial effects of meditation happen.
The heart has also a biochemical and energetic connection with the brain. In its biochemical function, the heart produces hormones, such as the atrial natriuretic factor which influences blood pressure; and the oxytocin, the so called love hormone, which relates to tolerance and adaptation. It also produces neurotransmitters (e.g through cardiac adrenergic cellules), which affect the amygdala. The energetic connection between the heart and the brain is mediated through its electromagnetic field. The heart has an electromagnetic field being 100 times more powerful than the one produced by the brain, and 60 times wider. This field embraces each cell of our body and also surrounds us. This electromagnetic field acts as a modulatory wave which codifies and communicates information to the whole body (systems and cells); moreover, it also acts outside our body between persons. This implies that people who get in contact with a person being in a coherent state, become coherent themselves.
Summarizing, to reach the inner rhythm and a cardiac coherence is what meditation strives to accomplish. In fact, in all the languages from the southwest of Asia, heart and mind have one common term. The Sanskrit word “citta” or the Tibetan word “gem” mean both – “heart” and “mind”. The word “meditation” means “to cultivate”; therefore meditation serves the cultivation of heart and mind.
The effects of meditation in our bodies: Scientific evidence
The rising of meditation practice is being paralleled by an increase of scientific studies analyzing its effects in the human being. When searching for the word “meditation” in the title and in the abstract of the scientific papers indexed in one of the worldwide most frequently used medical database (i.e. PubMed), an important increase of the number of papers on meditation annually published has been noticed in the last decade (see figure 2).
When the word of “mindfulness” is used in title and abstract, this increase is significantly higher (see figure 3). Mindfulness is a modification of Zen meditation which started to be taught as a therapy in Eastern health care centers in the USA to reduce stress (Mindfulness-Based-Stress-Reduction Program) and it is based on “paying nonjudgemental attention to the present moment” (6). The increase of published papers dealing with meditation shows that nowadays meditation is a target of scientific study.
The scientific evidence shows that meditation has an effect on the physical, mental and emotional body. Figure 4 summarizes the type of effects produced by meditation in the three bodies. Hereafter, examples of studies providing proof of several effects of meditation in our bodies are presented.
In the physical bodies of people who meditate a significant (p<0.05) reduction of both pain unpleasantness (by 57%) and pain intensity (by 40%) could be shown compared with people who simply rest (7). In a randomized controlled trial with 25 meditators and 16 controls, a significant increase in antibody titers concerning influenza vaccines was found indicating a stimulation of the immune system (8). Another study showed that guided meditation with a visualization of ultraviolet rays lead to quicker epidermis healing (4 times quicker) than in those persons who received ultraviolet rays physically (statistically significant differences, p<0.05). The authors of this study concluded that there is something in the mind that affects the expression of the genes which control cellular replication (9). Another study with sixty-one healthy adults (thirty-three of them being trained in compassion meditation and twenty-one of them having participated in health discussion groups) showed that after being exposed to a stress test, those who meditate for a longer time show a statistically significant (p<0.05) decrease in interleukine-6 and cortisol, both substances being associated with distress (10). Transcendental meditation has also shown a statistically significant decrease in carotid atherosclerosis (p<0.045) compared with those who received health education. A randomized controlled trial study with 201 black men and women with coronary disease, showed that those in the transcendental meditation group reduced the risk of cardiac events by 66% (mortality, myocardial infarction, stroke and blood pressure) (statistically significant, p<0.003) compared with those in the education group. This well designed study led the American Heart Association to the inclusion of meditation into their clinical guidelines on the secondary prevention of cardiac disease (11). It could also be shown that Transcendental meditation decreases insulin resistance in diabetic patients compared with those following health education (p<0.01) (12).
Lonely, elder adults suffer from an increased expression of pro-inflammatory genes as well as increased risk for morbidity and mortality. A small randomized controlled trial showed that after 8 weeks those being trained in mindfulness-based stress reduction (MBSR) showed a trend to increase the C reactive protein (related with inflammatory processes) and to reduced loneliness compared with a small increase in loneliness in the waiting-list control group (13). Another rigorous study showed that a group of patients with a chronic inflammatory condition being trained in MBSR had a significantly smaller post-stress inflammatory response compared to those who received health education. This led to the conclusion that MBSR might have a therapeutic benefit concerning chronic inflammatory conditions (14).
Meditation also promotes neuroplasticity. It is associated with an increase of cortical thickness (15,16), the greater this thickness is the better are the brain functions. When meditation has been performed for a longer time (17) an increase of the grey matter density in the brain stem produces larger hippocampal and frontal volumes of grey matter, which lead to the cultivation of positive emotions (18). People who meditate have more neuronal connections among the different brain areas and show less brain atrophy with age (19). The longer one meditates the better the achieved results are.
It was also shown the practice of mindfulness reduces the number of episodes in case of recurrent depression. A study with 84 patients with severe depression who previously were treated with drugs has been conducted. The patients were assigned to three groups (meditation, drugs, placebo). It was shown that mindfulness and medication were equivalent concerning the prevention of new events of depression. The authors concluded that for those patients who do not want to continue with drugs, meditation is an effective therapy (20). This study convinced the UK National Health System to recommend MBSR for those patients with a history of three or more events of depression. Mindfulness also showed the improvement of self-knowledge (21), decreased mind wandering and an improved cognitive function (22), and the possibility to reach sustained concentration (23).
Studies show that meditation changes the DNA in the cells. In a descriptive study, after three months of meditation, participants showed an increase of the telomerase level (24). Telomerase is an enzyme which reverses the process of shortening the telomere. Telomere are found at both ends of a chromosome. They protect the ends of the chromosomes from deterioration. Telomere shortening is associated with aging, mortality and aging-related diseases. It has been linked to chronic stress. Reversing the shortening of telomere by temporary activation of telomerase may be a potent means for the deceleration of aging. Another study shows that loving-kindness meditation practice is associated with longer telomere in women (25). This was tested in a group of 15 active meditators and compared with 22 non-meditators. There was a control of the analysis on all factors which could let come up the suspicion of fake results. Those who meditated focusing in an unselfish kindness and warmth towards all people remained with longer telomere afterwards in comparison to a group which did not meditate at all. The authors of this study concluded that meditation can be a source of longevity, but if meditation is practiced through goodness it will be able to improve the quality of life of both those who practice and those who surround them. Two years later, a well-designed study with 88 female survivors of breast cancer, corroborates that mindfulness maintains the telomere length while the telomere in the members of the comparison group which did not meditate were shortened (statistically significant difference p<0.05) (26). This was the first study with the author’s conclusion that there is strong evidence that meditation can affect key aspects of our biology.
Scientific evidence has been found on loving-kindness meditation practice also influencing our surroundings. A blind study performed in the Wake Forest University (North Carolina), showed that when doctors in their office are in a coherence state, communicating non-verbal love and compassion to their patients, the latter decreased their stress and increased their feeling of peace and relaxation thus experiencing an improvement of their cardiac frequency. Authors concluded that extending compassion to others is a good “treatment” (27). Another study carried out in Washington DC aimed to decrease criminality by carrying out meditation. This study showed that when 2,500 people were meditating, there was a 25% decrease in criminality indexes in Washington (28). A small group of people influenced the Washington population (i.e. 1,5 million citizens). A previous study carried out during the Libanese-Israel war, also showed the positive impact of group meditation. This study included different groups of expert meditators placed in Jerusalem, Yugoslavia, and the USA. They were asked to meditate in the geographical area of the war at different intervals during 27 months. The study was controlled if there were any factors which could lead to the thinking that the results were affected by external causes not being directly linked to meditation. The results showed a 40-80% decrease in violence levels each time the groups were meditating. Even higher reductions were achieved when the group of meditators was bigger. Other observed effects were a decrease in number of people being killed per day (from 12 to 3), a 68%-decrease in war injuries, and the conflict intensity decreased to 48% (29).
Most studies of the effects of meditation have been done with adults. Nevertheless, some studies about the effects of meditation in children have been published. The scientific evidence shows that transcendental meditation in children has the following effects: an increase of the percentage of school graduation of 21% (30), a 10%-improvement of the Grade Point Average Test (31), an increase of school attendances and decrease of academic failure in secondary schools (32), a reduction of the ADHD-symptomatology (33)an increase of the intelligence and creativity (34), a decrease of psychological distress, including anxiety and depression (35), and the reduction of the number of burnouts and stress among teachers (36).
Meditation may become a fashion in western societies. Nevertheless, welcome fashion since its effects in our bodies will contribute to make human beings better, physically, mentally and emotionally. Nevertheless, to produce and maintain the effects, rhythm and perseverance is necessary as shown by scientific evidence. Moreover, if one does not meditate just for himself only but instead for the whole human race and the planet, it will contribute for the creation of a better world. The process of meditation can be described with the words of the astronaut Neil Armstrong when he stepped down the moon for the first time: “a small step for man, one giant leap for mankind”.
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