Understanding the nervous system
This is an incredibly important time to discuss nervous system health and how we can best support it from a range of disciplines. Whether as a direct result of contracting the Covid-19 virus or simply as a consequence of living through a pandemic, it is commonly known that these last years have pressured nervous systems globally with the result being an upsurge in conditions such as tension, anxiety, depression, insomnia, fatigue and post-traumatic stress. Thankfully, Traditional Chinese Medicine (TCM) has much to offer in this domain, both in terms of treatment and advice for self-care.
The Autonomic Nervous System
Stemming from the brain and subdivided in to the central and peripheral nervous systems, the nervous system is the control centre that guides us through our daily lives, governing everything from speech and movement to respiration, thoughts and feelings.
Within the peripheral nervous system is the autonomic nervous system (ANS). The ANS controls involuntary processes such as our heart rate, blood pressure, breathing and digestion via the sympathetic (activating) and parasympathetic (calming) nervous systems. It is the ANS that is activated when we experience the ‘fight’ or ‘flight’ or ‘freeze’ response to threatening situations and it is the communication between the hypothalamic-pituitary-adrenal (HPA) axis that regulates this response. (1)
When we encounter stress or a perceived danger, the sympathetic nervous system galvanises us to react (fight) or flee (flight) through a hormonal response. The hypothalamus, located at the base of the brain, releases corticotropin-releasing hormone (CRH). CRH prompts the pituitary gland to secrete adrenocorticotropic hormone (ACTH) which then promotes the adrenal glands to release the ‘stress hormone‘, cortisol. The adrenal glands also release adrenaline and noradrenaline, which prepare the body to fight or flee by increasing blood pressure, heart and breathing rates. Once blood levels of these hormones reach a certain level they will send inhibitory messages to the hypothalamus and this negative feedback returns the body to homeostasis. In the face of chronic stress, however, this equilibrium is not achieved and we suffer what is known as hyperactivation of the HPA axis. (1,2)
How do nervous system disorders work in TCM?
Yin and Yang
“Yin ping yang mi, jing shen nai zhi.
If yin is level [calm] and yang is secret [unobtrusive],
the spirit is therefore in order” (3)
The Kidneys are the foundations of yin and yang in the body and kidney essence provides the material basis for the brain and spinal cord. (4) They are, therefore, integral to an understanding of the western nervous system.
At the most fundamental level, chronic HPA axis overactivity is a disharmony of the yin and yang energies. Where yin is cooling and sedentary, yang is warming and active. Where yin calms, yang stimulates. Opposites, they also rely on each other to generate and tame one another to maintain balance.
In cases of HPA axis hyperactivity we are – at least in the early stages – looking at overabundant and/ or unrestrained yang energy. A stressor has called the yang energy in to action to enable us to ‘fight’ or ‘fly’, and where yin would ordinarily restrain the yang to bring the body back to a place of equilibrium, this has failed to occur. The stressor has either been ongoing or pre-existing weaknesses have rendered the body unable to control and anchor the yang. The heating, stimulating yang energy is left unchecked and the fall-out from this affects us on many levels, including the disturbance of our shen (spirit/ mind). Left untreated, this excess condition, typically involving the heart and liver systems, will eventually lead to one of deficiency (in particular, of the heart, spleen and kidneys). (2) This depleted state is often termed, ‘adrenal fatigue’.
In TCM, our shen is a broad concept referring to everything from our mental functions, thoughts, memory, emotions and sleep as well as the more ethereal concept of our ‘spirit’. As mind and body are inextricably linked in TCM, the shen is believed to reside in the heart and is anchored and nourished by blood and yin. If these are weak, our shen will lack stability. It is also easily agitated by excessive heat. (4) When we look at conditions affecting the nervous system, shen disturbance is typically present.
Understanding the root
In TCM, there is no specific understanding of the nervous system or HPA axis dysfunction as we know them in allopathic medicine. However, as chronic HPA axis activation is illustrated perhaps most explicitly in the anxiety disorder post-traumatic stress disorder (PTSD), where the autonomic nervous system remains activated long after the initial trauma, we may look to the main TCM ‘patterns’ (constellations of signs and symptoms) seen in PTSD cases to gain a general understanding of how TCM interprets an overactive sympathetic nervous system (bearing in mind that not all symptoms will be present in all cases). The excess, relatively acute, patterns tend to involve the liver and heart systems and the deficient, chronic patterns, the heart, spleen and kidneys. (2)
Liver qi stagnation
The liver governs the smooth flow of qi. When we are stressed, liver qi stagnates creating physical and mental tension, moodiness, irritability and/ or depression. This can be accompanied by feelings of abdominal discomfort below the ribs and digestive issues (belching, nausea, poor appetite, a churning feeling in the stomach), where stagnant liver qi has invaded and disrupted our digestive function (controlled by the spleen and stomach). In women, we will often see menstrual irregularities and pain. The radial pulse will feel ‘wiry’, taught like a guitar string, reflecting the constraint of energy in the body. (2,4)
Liver qi stagnation with heat
If Liver qi stagnation persists, it generates heat or even fire, like the rubbing together of sticks. Here we will see an exacerbation of liver qi stagnation signs (e.g. extreme irritability) accompanied by heat signs such as: red eyes and face, dry throat, thirst, burning abdominal discomfort, dry stools, dark yellow urine, a red tongue with a yellow coat and a pulse that is now both rapid and wiry. The level of shen disturbance here is greater and one will suffer from insomnia and possible nightmares due to the rising heat disturbing the shen. Ascending heat may also cause high blood pressure, dizziness and severe headaches. (2,4)
As it rises, liver fire readily transfers to Heart fire. This pattern is similar to that of liver fire, but there will be symptoms such as intense mental restlessness, palpitations, a sensation of heat in the chest, burning mouth and tongue ulcers (the tongue is an “offshoot of the heart” (3, p208)) and impulsiveness. Insomnia is characterised by frequent waking and nightmares. The urine will again be dark and may even be painful or contain blood in cases where the intense heat from the Heart has transferred to the small intestine (the heart’s partner in TCM). The pulse will again be rapid but may also be irregular, reflecting the heart’s agitation. In TCM, the tip of the tongue relates to the heart and in cases of heart fire it will be red and swollen. (2,4)
Phlegm fire disturbing the shen
Qi stagnation can impair the processing and circulation of fluids as well as impacting digestion. This can lead to the generation of phlegm. Phlegm stagnation may also lead to fire, agitating the shen. Clinical symptoms are similar to heart fire but, as phlegm ‘obstructs the orifice of the mind’ in TCM, the shen disturbance is typically more pronounced and there may be a tendency to being easily startled, confused thinking, aggression and “excessive ranting”. (2, p24) Again, there will often be dizziness and hypertension from the heat flaring upwards. The pulse will feel rapid and ‘slippery’. (2,4)
Heart blood and Spleen qi deficiency
Over-thinking and rumination leads to the consumption of qi and blood. In this deficient pattern, the heart (and, therefore, shen) lacks nourishment from blood and digestion (and, therefore, qi and blood production) is impaired. There will be fatigue, poor appetite and digestion, great anxiety, timidity, palpitations, insomnia (particularly falling asleep) and memory impairment. The complexion and tongue are pale, the pulse is weak and ‘thin’. (1,3)
Heart and Kidney not communicating
In TCM, the heart belongs to the fire element and the kidneys, water. Like yin and yang, they keep each other in check; Heart fire (yang) warms the kidneys and kidney water (yin) cools the heart. Excessive mental activity and overwork can sever this communication by depleting kidney yin, resulting in hyperactivity of heart fire and shen disturbance. The nature of the shen disturbance is that of the excess heart fire pattern above but here it is paired with typical kidney yin deficiency signs such as sore low back and knees, tinnitus and nightsweats. The pulse will be rapid and thin. (2,4)
Signs and symptoms
Possible conditions involved in chronically active sympathetic nervous systems:
- impaired memory
- confused thinking
- high blood pressure
- irritable bowel syndrome (IBS)
Chinese herbal medicine tends not to use herbs individually but in synergistic formulae. It is important to consult a qualified TCM practitioner as they must be carefully prescribed and modified to match the individual’s presenting symptoms, environment and constitution.
Substances that calm the spirit
In the TCM materia medica, we have a category of herbs known as substances that calm the spirit which work predominantly on the heart and liver to address issues such as irritability, insomnia and anxiety. Within this category are ‘herbs that nourish the heart and calm the spirit’, such as:
Suan zao ren (Zizyphus spinosae): Jujube seeds is a commonly-used sedative herb that alleviates irritability, insomnia and anxiety with palpitations in cases of yin or Blood deficiency. The tonic properties of suan zao ren lend it to safe use in the elderly and in children. (5) It has also been shown to reduce blood pressure. (6) It is the primary herb in the classic formula, Suan Zao Ren Tang (Sour Jujube Decoction), used widely in TCM to treat insomnia from yin and Blood deficiencies. (7)
Yuan zhi (Polygala tenuifolia): Polygala, is a bitter, pungent, slightly warming herb that nourishes the heart and clears phlegm that is disturbing the spirit. (5,6) It is also an important herb for re-establishing the communication between the heart and kidneys. (8)
He huan pi (Albizzia julibrissin): Also known as Mimosa tree bark. While this is a herb that is mild in its action, the English translation, “collective happiness bark”, (5) goes some way to illustrate its importance in TCM as a herb for steadying and elevating our emotions. It does so primarily by alleviating contrained liver qi, though large doses and prolonged use is needed for this. (8) He huan hua (Flos albizziae julibrissin) the Persian silk tree flower, is also used to calm the spirit, especially in cases of great qi stagnation and where Stomach qi has been impacted (ie. poor appetite). (5,8)
Within the shen-calmer category, we also have ‘substances that anchor, calm and settle the spirit’, used for their tranquillizing effect in cases of ascendant yang energy. (5) These herbs (e.g. mu li (oyster shell) and long gu (fossilized mammal bones)), however, are minerals and shells and are not approved for use in the UK.
Herbs that regulate qi
Chai hu (Bupleurum chinense, Bupleurum): While chai hu belongs to the category of herbs that ‘release the exterior’, here we will explore its ability to regulate the qi in cases of emotional instability due to liver qi stagnation. It is a bitter, cool herb that both alleviates liver qi stagnation and benefits and protects the spleen qi (our digestive energy). As this herb ‘raises yang’, it must be avoided in cases of liver fire or where yang is rising. (6) It is the chief herb in Xiao Yao San, one of the most popular TCM formulas and the go-to formula for stress and depression. (7)
Xiao yao san (XYS) translates as“Free and Easy Wanderer” or “Rambling Powder” for its ability to free up and smooth the flow of our energy and moods. Along with chai hu, it contains dang gui (Angelica sinensis, Chinese Angelica root), bai shao (Paeonia lactiflora, white Peony root), bai zhu (Atractylodes macrocephala, white Atractylodes root), fu ling (Poria cocos, Poria), bo he (Mentha haplocalyx, Mint), wei jiang (Zingiberis officinalis recens, roasted ginger), and zhi gan cao (Glycyrrhiza uralensis, honey-fried licorice root). This combination regulates qi, strengthens the digestion and tonifies blood. (7)
A meta-analysis reported that use of XYS alongside antidepressants was more effective in alleviating symptoms of depression than antidepressants alone and previous studies have demonstrated that XYS may reverse “chronic stress-induced anxiety-like symptoms” by regulating hypothalamus and HPA axis activity. (9) It has also been posited that XYS may help to alleviate depression by reducing neuroinflammation (inflammation of the brain and spinal cord) stemming from a gut microflora imbalance. (10)
Ren shen (Panax ginseng): Ginseng, has been used in TCM for millennia to treat conditions of weakness affecting the spirit. In modern research, it has been shown to be beneficial in cases of depression and anxiety where hyperactivation of the HPA axis is present by reducing CRH, ACTHand cortisol. (11) Warm and sweet, it is said to strongly tonify qi and blood and quiet the shen and to this end is typically combined with other qi and blood tonics such as dang gui and long yan rou (Euphoria longan, Longan fruit). (6)
Ren shen is present, often the chief herb, in many formulae where the shen is suffering as a result of deficiency, including Gui Pi Tang (spleen restoring decoction) – a popular formula used where spleen qi and heart blood have become deficient, typically as the result of mental taxation or rumination. (7)
Herbs that clear heat
Where Liver qi stagnation has led to heat (as it often does) and, therefore, more extreme shen disturbance, we may use a modification of Xiao Yao San called Jia Wei Xiao Yao San. Bitter and cold, mu dan pi (Paeonia suffruticosa, Peony tree) and zhi zi (Gardenia jasminoides, Gardenia) are added to the original formula to quell heat and ascending liver fire. (7)
Sheng di (Rehmannia glutinosa): Rehmannia is another popular herb used in cases where heat agitates the spirit. It does this by not only clearing heat and “upwardly blazing heart fire” (6, p68) but also by nourishing yin. It is the primary herb in the formula Tian Wang Bu Xin Dan, illustriously named, ‘Celestial Emperor’s Special Pill to tonify the heart’. It is used in cases of yin deficiency of and miscommunication between the heart and kidneys with heat signs. (7)
TCM Diet tips
In cases where heat and/ or yin deficiency is present it is important to avoiding warming foods and stimulating substances. These include spices (think chilli, pepper, garlic, cinnamon etc), red meat (especially lamb), fried foods, sugar, caffeine and alcohol. Incorporate more cooling foods such as greens, celery, cucumber, daikon radish, spinach, apples, watermelon, mint, chrysanthemum tea, fish (ocean).
In cases of phlegm, avoid damp-forming foods – excessive cold, raw food, greasy, fatty foods, dairy, bananas, peanuts, sugar, flour products, avocados and incorporate foods that cut phlegm such as pear, turnips, radishes and seaweeds.
In cases of spleen qi deficiency, likewise avoid damp-forming foods and nourish spleen qi with warm, easily digested food, in particular pumpkins, squashes, sweet potatoes, rice, dates, chicken and ginger.
The sour flavour is astringing and contracting and, therefore, excess sour foods should be avoided in cases of qi stagnation. (12)
Incorporate relaxation techniques in to your everyday life. Some examples:
- Meditation and mindfulness
- Descend or ground ascendant energy by walking barefoot in the park, massaging the soles of the feet or having a warm foot bath.
- Dan tian breathing (or pranayama) is simply diaphragmatic breathing where we breathe down in to the dan tian, the space said below the umbilicus said to house our life energy. Place hands on lower belly and slowly breathe in to this space, feeling it expand, for 5 or more minutes, or whenever feeling anxious. By controlling our breath in this way and extending the exhalation so that it is longer than the inhalation, we let our nervous systems know that we are not in a threat situation.
- Smiling likewise inhibits the stress response by inhibiting the stress response and triggering the release of endorphins. (13)
- Acupuncture has a long history of treating nervous system disorders. A particular method commonly used in the treatment of PTSD is the NADA protocol, an auricular acupuncture treatment involving five points on the ear – ‘shenmen’ (“spirit gate”), sympathetic (nervous system), Kidney, Liver and Lung/ Heart. Initially developed to support drug detox, the NADA protocol is now widely used, particularly in the US, to support combat veterans with PTSD. (14)
- Time in nature. In TCM, we believe that time in nature – specifically, lush, green environments – calms the spirit and nourishes our yin energy. In Japan, this is called shinrin-yoku (‘forest bathing’) and has been shown to decrease sympathetic nervous activity, blood pressure, heart rate, cortisol, adrenaline, anxiety, depression, anger, fatigue and confusion while increasing parasympathetic nervous activity and energy.
In TCM, walking is a gentle way to free up liver qi constraint. Regular, gentle exercise has been shown to reduce adrenaline accumulated in the bloodstream from stress. Medium to high impact exercise, on the other hand, elevates cortisol levels. (15)
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