Recently I had the great pleasure of visiting with my friend and colleague Solomon Ben Ezra and speaking on his experiences with meditation as a practitioner and inspiring teacher. Our discussion can be found on the podcast and also on video.
I have discussed many aspects of mind-body health, meditation, and brain health on this blog and on my podcast as this aspect of health is tremendously important.
In a nutshell, unregulated stress can wreak havoc on many organ systems of our body. Let alone, the toll it takes on our mental health. A stress-management practice has become essential much as exercise became essential when we moved to a more sedentary lifestyle at the dawn of the industrial revolution.
We are going to take deep dive in this post on meditation, how it works, and some resources to get people started. I first wrote this article in 2005 and have added some updates and likely will update again. First, a little bit of background.
History of Meditation as a Health Intervention
Meditation has long been associated with eastern spiritual practice, however is now recognized and utilized throughout western society. To understand meditations' emergence, consider that the Shambhala Mountain Center, a meditation retreat center in the Colorado Rockies increased from 1342 visitors in 1998 to a projected 15,000 visitors in 2004.[i] During the past 30 years, meditation has become a scientifically studied intervention to address health concerns ranging from cancer, immune dysfunction, cardiovascular disease, and psychological/behavioral dysfunction.[ii],[iii],[iv],[v] . The National Institute of Health defines meditation as a conscious mental process that induces a set of integrated physiological changes termed the relaxation response [vi] . This term was coined by Harvard professor of Medicine, Dr. Herbert Benson, after researching biophysiological effects of Transcendental Meditators in 1967.
Forms of Meditation:
There many different forms of meditation being practiced; however, the most researched forms are from the schools of Transcendental (concentrative-type) Meditation and Mindfulness technique. Most of the meditation today comes from concentrative (i.e. TM), mindfulness (MBSR), and Movement (i.e. Tai chi). Because these techniques differ it is difficult to make a wide range generalization of the effects of meditation as a whole. Below is a comprehensive list of the different forms of meditation.
.The Anatomical and Physiologic impact of meditation
Because different forms of meditation affect the nervous system in unique ways there has often been conflicting data as it relates to neuroendocrine involvement with meditation. Regardless of the variety in cause-and-effect relationships of variant forms of meditation, advancements of science have allowed us to understand how meditation acts upon the central nervous system and the endocrine system. Much of this data has been determined by measuring blood values of meditation subjects. However, we are now capable of understanding more of the impact of meditation through imaging techniques. In fact, functional magnetic research imaging (fMRI) has been used to identify and characterize the brain regions that are active during meditation. This research suggests that various parts of the brain known to be involved in attention and those concerning autonomic nervous system regulation are activated, providing a neurochemical and anatomical basis for the effects of meditation on various physiological activities.
In the higher centers of the brain, meditation has been shown in one study to produce significant increases in left-sided anterior brain activity, which is associated with positive emotional states.[i] In other studies meditation has shown to generate response in the prefrontal cortex (PFC) of the right hemisphere and cingulate gyrus of the limbic system. The limbic system is related to emotional areas of the brain and includes regions that are called aversion centers or gratification centers of the brain. If an aversion center is stimulated a person will experience fear or sorrow. On the other hand, stimulation of gratification will result in pleasure. There are a number of these centers dispersed throughout the limbic system. [ii],[iii]. The PFC and cingulate gyrus are generally associated with activation during willful or high concentration activities. The prefrontal cortex also has been connected with some of the most distinct human intellectual traits such as judgment, foresight, sense of purpose, sense of responsibility, and sense of social propriety.[iv]This most likely is correlated with forms of meditation that involved sustained concentration on a word or mantra as seen in TM.[v]
We are also aware of meditations' effect on the Thalamic regions of the brain, which generally functions as a gatekeeper of stimulatory and inhibitory data. Most of the thalamic effects that have been observed during meditation has been due to the inhibitory neurotransmitter GABA which appears to be increased during meditation. GABA functions on the sensory or inhibitory effects of the Thalamus. Increased Dopamine levels are also assumed to be involved with this effect on the Thalamus.[vi] In regards to health promoting effects of meditation, this is interesting because the key function of the thalamus is to receive sensory information of many sorts (temperature, pain, vision, and so on) and distribute it to the specific regions in the cerebral cortex to decode it. [vii]
We are also aware of the direct impact of meditation on higher neural regions. For example, the frontal lobe, the most highly evolved part of the brain that is responsible for reasoning, planning, emotions and self-conscious awareness, tends to lower functioning during meditation. In the parietal lobe, the part of the brain whose major function is processing sensory information, slows down during meditation. The Thalamus, which generally functions as a gatekeeper of stimulatory and inhibitory data, reduces the flow of incoming information.Finally, the reticular formation, the brain’s alert enter, has decreased arousal signals during meditation.
The Hypothalamic Pituitary Axis:
The main system linking the endocrine and nervous system and that which applies to meditation is the Hypothalamic Pituitary Axis. The interactions that occur along this axis most aptly describe the relationship between the endocrine system and nervous system. In general, the hypothalamus has two main regions that have opposite functions. The caudolateral region when stimulated produces behavior associated with anxiety these include 1) increased sympathetic activity of the visceromotor system 2) increased aggressive behavior, 3) increased hunger, and 4) increased body temperature. In contract the rostromedially hypothalamus typically produces behavioral manifestations that are generally associated with contentment. These include 1) increased activity of the parasympathetic division of the visceromotor system, 2) increased passive behavior 3) increased satiety and 4) decreased body temperature.[i]
The hypothalamus main function on the Hypothalamic Pituitary axis is the regulation of factors of adrenocorticotropic hormone (ACTH) and its counterpart B-lipotropin via Corticotropin Releasing Hormone (CRH). Afferent signals arrive which influence the release of CRH. These include afferent signals coming from;1) The Limbic System which carries emotional “emotional stimuli” to the hypothalamus 2) Reticular Formation: which carries systemic stimuli to the hypothalamus; 3) Hypothalamic and Anterior Pituitary Cells sensitive to Circulating Blood Cortisol Levels and 4) Suprachiasmatic Nuclei (diurnal rhythm sensitivity). In addition, catecholamine (Norepinephrine/Epinephrine) release is coordinated through afferent pathways from the limbic region concerned with emotion. Also, stimulation of caudolateral, especially the lateral areas, produce diffuse sympathetic discharge and increased adrenal medullary secretion like the mass sympathetic discharge seen in animals exposed to stress. There are also additional separate areas for the control of norepinephrine and epinephrine secretion.
A couple additional points about CRH worth mentioning. CRH is potentiated by Antidiuretic Hormone (Also known as Arginine Vasopressin) which can be released into the same hypothalamic region. And, research now shows us that CRH is responsible for more than just ACTH secretion, where CRH receptors have been identified on inflammatory cells. This gives clues that peripherally released CRH may be pro-inflammatory. Finally, CRH secretion has now been identified to be associated in other besides stress including increased ACTH/adrenal activity associated with stress but also certain associated behavioral symptoms such as depression, sleep and appetite disturbances and psychomotor changes.[ii]. This author postulates that this may be a critical link to understanding sustained levels of cortisol that may eventually lead to adrenal failure.
The Pituitary Gland acts in direct response to the hypothalamic function. The hormones produced by the pituitary gland which concern meditative technique is ACTH. The biosynthesis of adrenal hormones is dependent on ACTH, which stimulates the rate limiting enzyme cholesterol desmolase. Without this step the cholesterol precursor will not produce the adrenal hormones. The adrenal hormones resultant of ACTH are adrenal glucocorticoids (i.e., Cortisol), mineralocorticoids (aldosterone), and adrenal androgens (Dehydroepiandrosterone (DHEA) and Androstenedione). Normally there is a negative feedback where free glucocorticoids inhibit ACTH secretion from the pituitary gland and also to some degree inhibiting CRH secretion from the hypothalamus. So, as we have found one of the key afferent factors that affect the hypothalamus and the amount of free corticosteroid are the main factors that regulate ACTH secretion[iii]
Other important pathways must be considered when understanding the link between meditation and neuroendocrine effects. One pathway is concerning Serotonin which may be elevated in mediation and serves as a precursor to melatonin in the pineal gland. Serotonin has apparently been shown to elevate CRH and subsequent levels Apparently a direct synaptic connection between serotonergic terminals and corticotropin-releasing hormone (CRH)-containing neurons in the paraventricular nucleus of the hypothalamus has been described. Precursors of 5-HT (the precursor to serotonin) or drugs that enhance the effect of 5-HT increase CRH in portal blood and ACTH in plasma. In addition to effects at the hypothalamus, 5-HT may have direct effects on the anterior pituitary to stimulate the release of ACTH and at the level of the adrenal cortex to regulate release of corticosterone or cortisol. Actions of serotonin on 5-HT1A, 5-HT2, 5-HT3 and 5-HT4 receptors seem to be involved in these effects on the hypothalamic-pituitary-adrenal axis.[iv]
Hypothalamic-Pituitary-Axis and Disease
It has been known for a long time that vital stress induced hypercortisolism induced by surgery, trauma, or sepsis is associated with augmented release of ACTH, which in turn is presumably driven by corticotropin-releasing hormone (CRH), cytokines and noradrenergic system. Accordingly, circulating aldosterone rises markedly, probably under the control of activated renin-angiotensin system. Hypercortisolism acutely shifts carb, fat, and protein metabolism, so that energy is instantly and selectively available to vital organs such as the brain and so that anabolism is delayed. Also, intravascular fluid retention (see aldosterone) and the enhanced inotropic and vasopressor response to respectively catecholamines and angiotensin II offer hemodynamic advantages in the flight or fight reflex. In addition, the hypercortisolism elicited by acute disease or trauma can be interpreted as an attempt by the organism to dampen down its own inflammatory cascade, thus protecting itself against over responses.
In prolonged illness, serum ACTH was found to be low while cortisol concentrations remained elevated, indicating that cortisol release may in this phase be driven by an alternative pathway possible involving endothelin.
The reason why ACTH are low in prolonged critical illness is unclear; a role for atrial natriuretic peptide or substance P has been suggested.
Also, circulating serum cortisol levels of adrenal androgen, Dehydroepiandrosterone sulphate (DHEA-S) which has
immunostimulatory effects on TH1-helper cells are low during prolonged critical illness.
Despite increased plasma renin activity, paradoxically low reduced levels are found of aldosterone and are found in protracted critical illness. This suggests a shift of pregnenolone metabolism away from both mineralocorticoids and adrenal androgen pathways toward glucocorticoid pathways orchestrated by an unknown peripheral force. Ultimately the compensatory mechanism may fail and lead to adrenal insufficiency. [i]
In wild baboons the chronic stress associated with subordinate social status appears to elevate the cortisol response to acute stressors, and to impair mechanisms of negative feedback.[ii]
Clinical Implications of Meditation on Neuroendocrine Related Disorders:
Because of our understanding of meditation and its impact on different systemic structures we can apply its techniques toward the treatment of disease and various disease risk factors. Below are some areas where meditation is being studied as a treatment method.
Stress Adaptation: Stress has often been linked to the degree an individual feels in in control of the variables of their particular situation. In one study long-term practitioners of TM demonstrated a more adaptive, low-stress profile than non-meditators. The profile of these subjects involved a stronger response to acute stressors, however a lower baseline cortisol level. This profile mimics the dominant male baboon in the wild compared to subordinate males which has been shown by researcher Sapolsky. The implications of this feature on health may be that chronically elevated baseline or average cortisol appears to increase risk for a variety of diseases. [iii] From this study we can safely assume that a meditation program would be very helpful in Maladaptive Stress Syndromes.
Improved Recovery from acute stressors
Frontal/prefrontal and limbic brain structures play a role in meditation, particularly, left-anterior regions of the brain and reward or motivation circuitry constituents are involved, This Left sided anterior activation found in meditation has been correlated with have been found to show faster recovery (improved auto-regulation) after negative provocation [iv] . Therefore, meditation may help people cope with stressful events and reduce stress-induced illness.
Chronic Fatigue Syndrome
Improving Cortisol Status in Chronic Fatigue Patients
Low cortisol levels are associated with fatigue. Arthralgia, myalgia, sleep disturbances, and mood disorders, have all been associated with Chronic Fatigue Syndrome and low cortisol. Chronic Fatigue Syndrome (CFS) has been termed mini-Addison’s [v]. Some members of the CFS population have been shown to have a blunted response to the Corticosteroid Receptor Hormone (CRH). It has been hypothesized that meditation may improve the response of the hypothalamus to CRH.[vi] This has been explained as an improved negative feedback loop.
Cancer Quality of Life:
One study showed that quality of life, mood, and symptoms of stress were found in “high-functioning “cancer patients undergoing an 8-week Mindfulness Based Stress program. . However, in this same study levels high levels of Cortisol, DHEAS, and Melatonin levels were apparently not influenced by the MBSR program.[vii]
Meditation and pineal Gland secretion of Melatonin
One study found that advanced meditators practiced a technique close to TM for 30 minutes twice/day, to have higher melatonin levels then non-meditators. However, this melatonin levels unexplainable decreased in long meditators (practicing more than 60 minutes). The mechanism by which meditation might lead to increased production and secretion of melatonin by the pineal is difficult to hypothesize at this stage, however other investigators have demonstrated that meditation can increase blood levels of noradrenaline and urine levels of the serotonin metabolite 5HIAA. Melatonin is synthesized in the pineal from serotonin, and the process is stimulated by noradrenaline acting on beta-adrenergic receptors on the pinealocytes.[viii] Melatonin is understood as a powerful antioxidant that theoretically can be helpful in the treatment of cancer. Melatonin has been found to inhibit the growth of several types of cancer including non-small cell lung cancer, hepatocellular carcinoma, metastatic brain carcinoma, renal carcinoma, and hormone sensitive cancers.[ix] Whether a therapeutic dose can be reached through meditation remains to be tested.
Blood Pressure/Heart Rate Regulation
A Zen Meditation technique called (Su-Soku) which involves sustained attention and breath control has been shown to create Frontal midline theta rhythm (Fm theta) activity, recognized as a distinct that activity on EEG, it reflects mental concentration as well as meditative state or relief from anxiety. The stimulation of this region of the brain was correlated with the Autonomic response in the cardiac system.[x] This can be interpreted as the effect meditation has on regulating heart rate and blood pressure.
Atherosclerosis: A double-blinded study showed that a TM stress program was associated with reduced carotid atherosclerosis when compared with health education in hypertensive African Americans. The likely mechanism explaining the reduction of carotid intima-media thickness (CIMT) is the decrease in excessive sympathetic nervous system activation. Evidence indicates that chronic psychosocial stress induces excessive adrenergic activation and sympathetic hyperresponsivity, leading to carotid atherosclerosis[xi]
Reducing Metabolic Syndrome X risk
Long-term Transcendental Meditation program reduced cortisol response to a metabolic stressor in a group of postmenopausal women. Since elevated cortisol may be a causal factor in producing the metabolic syndrome, a TM practice may play a role in preventing risks associated with coronary vascular disease and coronary disease.[xii]
Metabolic Syndrome X
Chest pain and exercise induced ST-segment changes in Metabolic Syndrome X patients have been shown to be positively influenced by the implementation of a Transcendental Meditation Program. [xiii]
Chronic Pain Management In a study designed by large HMO, the treatment group participated in a 16-hour, 8-week class teaching cognitive-behavioral techniques, the relaxation response, meditation, and stress management. Positive results were reported in measures of pain severity, negative mood, pain affect, and self-control.[xiv]
Other important areas that have cited meditation to be successful are addiction disorders, psoriasis, and depression. Areas to consider for future studies: Diabetes Management, Obesity Management, Auto-immune disease management.
Several Methods of clinical meditations have been employed. The three most commonly used have been Transcendental Meditation, MBR, and the Ornish Method. In this author's opinion the most helpful mediation programs to recommend would be those that are non-religiously affiliated and easy to incorporate into the patient’s lifestyle. Three well-known programs meeting these criteria are the following:
Transcendental Meditation: A form of meditation that is usually practiced twice a day for 20 minutes each session. It involves repeating a mantra (or repetitive saying). Its claim is to be non-religiously affiliated, however it has roots in Vedic traditions. It has apparently been used in over 600 studies evaluating its efficacy and impact on health.[xv]. For more information visit www.tm.org
Mindfulness Based Stress Reduction (MBSR): Jon Kabat-Zinn, famous University of Massachusetts researcher, author, and director of the Center of Mindfulness. This technique has roots in Buddhism however is not affiliated with the need to convert or practice Buddhism. The website claims ” Mindfulness is a way of learning to relate directly to whatever is happening in your life, a way of taking charge of your life, a way of doing something for yourself that no one else can do for you — consciously and systematically working with your own stress, pain, illness, and the challenges and demands of everyday life." The technique involves guided instruction in mindfulness meditation practices (meditation is usually twice a day for 30 minutes each session). The program also includes: gentle stretching and mindful Yoga, inquiry exercises to enhance awareness in everyday life, individually tailored instruction, group dialogue, daily home assignments, audio-cassette tapes and workbooks. Practitioners trained in these methods throughout the world can be found at University of Massachusetts Memorial Health Care Center for Mindfulness [xvi]
Ornish Method: Employed by Cardiologist Dr. Dean Ornish. He is a University of California-San Francisco based cardiologist who founded the Preventative Medicine Research Institute. He has looked at lifestyle-related changes in prevention of prostate cancer and cardiovascular disease. One of the arms of his research involves meditation as a stress-reduction technique. His program involves two daily 15-20 minutes meditation sessions. His techniques include stretching, meditation, deep breathing, progressive relaxation, and imagery. They do not provide instructors in this technique, however Dr. Ornish has written books incorporating this technique. This information can be located at www.pmri.org .  Dr. Ornish ahas many articles on mindfulness.
In the past 10 years, there has been an explosion of phone/computer-based apps that can help people get started on meditation perhaps in a less intimidating way then joining a course or program. These downloadable apps are designed to provide introductory information and practice meditation practices that are understandable to the everyday person. Here are some my personal favorites:
4. The Calm App
For those of you in the tech world you might want to check out what Google is doing with Search Inside Yourself .
Meditation has clearly demonstrated more than a placebo effect and its neuroendocrine mechanisms are becoming clearer. In addition, there are many proven indications for its use clinically. However, because of the great variability in meditation techniques it may be difficult to truly understand the capacity of its effect on human health. However, it should still be employed as a regular part of the day in my opinion. Yet, the form selected must resonate with the beliefs and comfort levels of the person practicing it.
Lastly, we need to respect to the origins of meditation and continue to honor and respect the traditions in which it was created.
Resources for this article can be found here