So 2014 is starting out with a blast of cold air and negativity for a lot of folks, from what I’ve been reading on the Interwebz. I don’t usually share my school work here on the blog because quite honestly it isn’t my favorite way to communicate my message. However in light of the general mood, I thought I would share this with everyone. I’ve removed the in text citations in hopes of making it a little more reader friendly, but I left a list of references at the end for people who are interested in reading more.
Pathophysiology of Chronic Stress and Modern Holistic Interventions
The word stress is a frequently occurring term in healthcare. The human stress response is a natural function of the central nervous system which evolved to protect us in dangerous situations. This is sometimes termed psycho-social stress but biological stress may also contribute to illness, so chronic stress is truly a bio-psycho-social phenomenon. Biological stress is generally attributed to oxidative stress. Oxidative stress results when the body produces more reactive oxygen than it is able to easily detoxify. This results in inflammation because the reactive oxygen that is not detoxified causes tissue damage which provokes the inflammatory response. While oxidative stress may play a role in diseases associated with chronic stress, it seems more likely that it is a result of diet. Pain is also a biologically occurring stressor however it is subjective and it has been found that the “single most salient component to defining the stressful impact of an event appears to be the perception of the event as aversive by the person.” The focus of this paper will be on the physiological impacts of experience of long-term exposure to psychosocial stress.
Stressors are defined as events that “require a physical, mental or emotional adjustment.” Stressors vary in level of intensity and they can be positive or negative. In 1967, researchers Thomas Holmes and Richard Rahe attempted to quantify certain life events such as marriage, personal injury, or change in residence, in order to use them as predictors of psychological and physical illness developed the Social Readjustment Rating Scale which was found to be predictive but with errors. The model has been criticized because inherently assumes that all people are equally resilient in the face of stressors. In 1983, Auburn University researchers determined that variables such as “higher levels of income and educational attainment” afforded an individual more resiliency. In recent years, modifications of this scale have shown that “the SRRS may be used as a scale measuring suicide risk.” While this information makes stress seem as though it is a purely sociological concern, it is far from that. Stress has distinctly physiological impact on the body.
To begin to understand the implications of chronic stress we must first understand the stress response which evolved in order to enable our body to handle “acute physical emergencies.” It is a function of the sympathetic division of the autonomic nervous system which means that these responses are instinctive and involuntary.
The stress response is modulated by the limbic-hypothalamic-pituitary-adrenal system and hormones known as glucocorticoids. The role of the limbic system is often overlooked in this process, but it is the amygdala which is constantly scanning our environment for dangerous images and sounds. Sensory information is processed by the lateral nucleus of the amygdala and if it is recognized as a threat, or a potential threat, the lateral nucleus generates an output to the central nuclei (CeA) which is then able to generate outputs which communicate to various components of the hypothalamic-pituitary-adrenal axis initiating the classic stress response. There is some evidence that the amygdala neurons which secrete noradrenaline and CRF are activated during stress. Projections sent from the amygdala to the parabrachial nucleus are responsible for increasing respiration. Projections sent by the amygdala to the hypothalamus are responsible for activating the sympathetic division of the autonomic nervous system. Sympathetic preganglionic neurons then stimulate the adrenal medulla to release epinephrine and norepinephrine and small amounts of dopamine.
The hypothalamus also releases corticotropin-relasing hormone (CRH) which results in the secretion of adrenocorticotropic hormone (ACHT) from the anterior pituitary gland. which then causes the adrenal cortex to stimulate glucocorticoids, such as cortisol. The pituitary also releases releasing endorphins, vasopressin and prolactin hormones. The release of other hormones in the body, such as insulin and insulin like growth hormone which slows digestion and growth processes, are suppressed and that energy is diverted to the limbs. Release of serotonin may also be suppressed as reduced serotonin levels seem to “increase responsiveness to stress” and the concentration of serotonin in the hippocampus seems to be higher during stress.
Ideally when the fear stimulus has abated the amygdala sends projections to the dorsal motor nerves of the vagus nerve which activates the parasympathetic nervous system and all body systems return to homeostasis. Chronic stress results when this fails to occur and the body exists in sustained periods of daily sympathetic stimulation lasting for weeks or months.
These neurotransmitters and hormones have specific effects on various body systems. In the cardiovascular system cortisol, epinephrine and norepinephrine cause your heart to beat faster and vasoconstriction which results in a more forceful heartbeat. These measures increase the oxygen levels in your blood. The arteries that lead to your muscles relax in order to increase blood flow to the muscles. Vasopressin causes your body to halt urine production and reabsorb the water back into your circulatory system. While these functions serve well on a short term basis, the long term effect of chronic stress create wear-and-tear in your cardiovascular system. Hypertension (high blood pressure) has the effect of over working the heart muscles and blood vessels causing them to thicken. Thickening of the heart muscle wall is termed left ventricular hypertrophy which may lead to arrhythmia. It may also lead to injury to the “points of bifurcation” in your blood vessels which leads to systemic inflammation. Inflammation in the blood vessels results in inflammatory aggregates which catch fat, glucose and LDL cholesterol as they travel through the blood stream. These substances become fibrous and eventually become what is known as atherosclerotic plaque. Due to this link between inflammation and heart disease, C-reactive protein, a substance secreted by the liver in response to injury, has shown to be the most predictive marker of cardiovascular disease.
Sympathetic stimulation also impacts the metabolic system. In an attempt to make as much energy as possible available insulin secretion is slowed so energy storage stops. Stress hormones also reverse other energy storage processes, breaking down triglycerides into more fatty acids, glycogen into glucose and non-essential muscles into their amino acid components to be utilized by the muscles that need the energy. Additionally glucocorticoids work to decrease cellular sensitivity to insulin. While these measures serve to meet the energy output needs of a situation during which one might need to run or fight, it is has negative health consequences when sustained. The first of these is that the elevated levels of glucose and fat in the blood stream contribute to the formation of atherosclerotic plaque as mentioned above. The second is the idea that large amounts of the glucocorticoid cortisol (hypercortisolemia) circulating through the body contributes to the chronic diseases related to insulin resistance, including metabolic syndrome and obesity. Abdominal fat cells are more sensitive to glucocorticoids which has resulted in the recognition of excessive abdominal fat as a symptom of insulin resistance.
In addition to metabolic problem stress induced inflammation and suppressed immune function may work together to contribute to gastrointestinal disorders such as irritable bowel syndrome. Ulcers are now attributed to the H. pylori bacteria, however not everyone who is infected with this bacteria gets ulcers. Lifestyle factors such as stress seem to increase susceptibility to ulcers possibly through the suppression of the immune system.
Chronic stress is also known to suppress immune function due to altering the leukocyte distribution in the body and suppressing cytokine and T cells. Glucocorticoids will stop the thymus from producing new lymphocytes and may even trigger programmed cell-death. Conversely while stress is known to suppress immunity, it is also known to exacerbate autoimmune conditions.
Additionally stress contributes to a phenomenon termed burnout which is a “work-related stress induced condition associated with memory problems, fatigue, a sense of inadequacy, and depressed mood.” This set of symptoms is sometimes mistakenly diagnosed as chronic fatigue syndrome. This set of symptoms has been theorized to occur due to the suppression of neurogenesis of cells in the adult hippocampus by glucocorticoids released during the sympathetic stimulation.
The preceding is not an all-inclusive list and the links between stress and many other conditions are currently being studied. Given the many negative impacts of stress, stress management is vital to improving health outcomes. Many modern herbalists have turned to the use of adaptogens. It makes sense that adaptogens are probably the most modern category of herbs given their use to treat a truly modern disease. In 1947 Russian scientists coined the term to as a “material claimed to increase nonspecific resistance of an organism to an adverse influence. In 1958, a Russian researcher, Isreal Brekhman, began researching herbs which might have this effect and meeting the following criteria: “it must be innocuous and cause minimal disorders in the physiological functions of an organism, it must have a nonspecific action, and it usually has a normalizing action irrespective of the direction of the pathological state.” Many herbs were identified by the researcher and his colleagues as adaptogens including, Eleutherococcus senticosus and Panax ginseng. Today herbals abound with lists of adaptogenic herbs. Withania somnifera is often recommended for stress. According to one study this herb and other adaptogens “counteracts many biological changes accompanying extreme stress including changes in blood sugar, adrenal weight and cortisol levels”
Another holistic approach is to increase parasympathomimetic activity in conjunction with lifestyle modifications and stress management techniques. According to herbalist Steven Horne, parasympathomimetic herbs work by “directly stimulating the cholinergic receptors [nicotinic and muscarinic] inhibiting cholinesterase and promoting acetylcholine release.” Unfortunately few of these have been studied, extensively. Pilocarpine found in a relatively obscure herb known as Pilocarpus jaborandi is a muscarinic cholinergic receptor agonist. The Veratrum spp. contains the chemical veratramine which also seems to have muscarinic cholinergic activity. Arecoline from Areca catechu is also a parasympathomimetic which activates the muscarinic receptors, however its use is not recommended due to possible toxicity although this information conflicts with the fact that the herb is commonly chewed on in South America. Lobeline, a constituent in Lobelia inflata effects the nicotinic receptors as does (obviously) the nicotine in Nicotinia tabacum.
Anti-adrenergic herbs are another category which inhibit the signals of epinephrine and norepinephrine (usually classified as nervines) include among others the Anemone spp. Leonurus cardiac (often a specific in arrhythmia) and Cimicifuga racemosa. In an animal study a root preparation of Cimicifuga racemosa demonstrated “myometrial relaxant effect which was potentiated after inhibition of excitatory muscarinic, alpha and beta adrenergic, H1-histaminergic and 5-HT receptors.” Rhodiola rosea has also been classified as an anti-adrenergic herb.
While adaptogens are considered safe for long term use these anti-adrenergic herbs are not and should be used as a short-term intervention allowing clients time to re-evaluate lifestyle choices and learn new coping mechanisms for that stress which is unavoidable. For those providers following a bio-social-psycho approach to herbalism, we find that there other useful adjunct therapies. Music therapy has been studied extensively for its ability to induce a calming effect in the body. Exercise has been shown to be a useful adjunct therapy. Breathing exercises such as those utilized in meditative practices and yoga have also shown to improve the ability to handle stress.
Having a well-established support system, is vital. Researchers have determined that “lack of social support and recognition by the environment is one of the most consistent risk factors” of stress related disorders. The latest research on mitigating this factor seems to be researching how the hormone oxytocin interacts with stress as a means of treating PTSD. Oxytocin, mostly recognized for its role in breastfeeding, also plays a role in the stress response in that oxytocin system enables us to find “repose and respite” by helping to activate the parasympathetic response. The release of this hormone also makes people more likely to seek social affiliation during times of stress due to the fact that the hormone oxytocin instills “greater confidence in others as well as a feeling of bonding.” Production and release of oxytocin is stimulated by pleasant social contact such as conversation, massage, sexual intercourse or playing with a pet. In cases where chronic stress is a concern, building community may seem daunting in light of a busy lifestyle. Making supplemental therapeutic recommendations that in turn stimulate oxytocin release such as massage, might also stimulate a client’s interest in seeking support networks.
A novel approach which seems to be favored by those who spend their time with plants is to recommend spending increasing amounts of time outdoors. In recent years a great deal of study has been devoted to the effect of green spaces on human well-being, leading one group of researchers to coin the term “Vitamin G” in reference to time spent in green places. Spending time in nature gardening or forest bathing has shown to mitigate the effects of stress. Japanese researchers studying the traditional practice of forest bathing or Shinrin-yoku concluded that forest environments promote lower concentrations of cortisol, lower pulse rate, and lower blood pressure, greater parasympathetic nerve activity, and lower sympathetic nerve activity.” Swiss researchers found that gardening leads to decreases in cortisol which “promote neuroendocrine and affective restoration from stress”. This may occur due to increased time outdoors or exercise. The argument could also be made that it is possible to have a pleasant conversation with your plants.
While using herbal preparations and adjunct therapies may alleviate some of the effects of chronic stress, there are still ethical questions concerning this approach. Alternative care providers may want to consider if mimicking the medical approach of reducing the effects of stress with pharmacological agents and coping mechanisms is truly the best approach for alleviating stress?
Are there systemic changes which need to occur in the American workplace such as shorter work weeks, longer vacations and higher wages which might better address the problem of chronic stress in our society? These questions are beyond the scope of this paper, but excluding them from consideration when discussing this topic would be remiss.
In arriving at answers to these questions, practitioners should consider the following statement by herbalist Sean Donahue, “Soviet scientists pioneered the use of adaptogens to make factory workers work longer and harder. The marketing of adaptogens to help people power through stressful lives in an economy that demands working two or three jobs to keep afloat is the capitalist equivalent. In both cases, to quote Dorothy Day, ‘Our problems stem from our acceptance of this filthy, rotten system.’ And until we can remove the obstacles to cure our solutions will be palliative at best.”
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