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Anxiety and the Autonomic Nervous System

by Jurriaan Plesman BA(Psych), Post Grad Dip Clin Nutr

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When studying anxiety attacks and phobias we should make a distinction between real fear and irrational fear.

I would like to elaborate on this using knowledge of biology as to what happens when we experience fear.

When we are faced with a tiger, or we encounter any kind of trauma, grief, rejection of a loved one and so forth, the body floods the system with adrenaline, the hormone of strenuous action and fear or fight. This hormone helps us to deal with the ‘danger’.

Adrenaline activates the Sympathetic Nervous System (SNS) which is a sub-branch of the Autonomic Nervous System.

It controls specific bodily organs to prepare us for fight or flight. These reactions are beyond the control of our consciousness and can be responsible for weird physiological symptoms.
The SNS dilates pupils of our eyes, shuts down the digestive organs, increases heart palpitations, relaxes the smooth muscles of bronchi and bronchioles, leading to “breathing problems”. The smooth muscles of the digestive tract is inhibited, so peristalsis stops, sphincter of the bladder also contracts and the bladder wall relaxes. This may lead to involuntary defecation, also known as encopresis. Blood vessels supply to the skeletal muscles are dilated. An overactive SNS is likely to open up blood vessels and flood your face, neck and ears in blushing. Other possible symptoms are: dizziness, shaking, trembling, (as when giving a talk in front of people), digestive disorders, swallowing problems, nausea, vomiting, or fear of vomiting or diarrhea, arrhythmia (irregular heart beats), ticks and restless legs, excessive sweating, depersonalization, incontinence, impotence, repetitive thoughts, ruminations, Anhedonia. It is obvious that these mental and bodily reactions helps to prepare the body for strenuous and quick actions in the face of environmental danger. The SNS diverts energy away from the vegetative to the muscular system.

Please note that in anxieties we see many symptoms – such as heart palpitations, stomach upsets and digestive disorders and so forth – that are the works of the SNS. Actions on the digestive system is often referred to as the Enteric Nervous System.

The Parasympathetic Nervous System (PSNS) – the other branch of the Autonomic Nervous System – on the other hand reverses the SNS and counteracts the SNS. This system is triggered by the neurotransmitter acetylcholine, which may be a important piece of information to people suffering from Bipolar Disorder. See: Bipolar patients. See notes below. The Autonomic Nervous System and its effects on organs see image here.

Thus this fear reaction is an important survival mechanism in the face of real danger.

The question is how is this related to anxiety attacks or the irrational fears that can wreck people’s lives.

The clue is adrenaline. The question is why should the body produce excess adrenaline out of the blue, without any trigger in the environment, causing us to have unexplainable anxiety attacks, phobias and heart palpitation? Hypoglycemia can cause to dump magnesium into urine, upsetting the delicate magnesium-calcium balance. This can trigger excess adrenaline secretion and contribute to hypertension (high blood pressure) and heart palpitations, anxiety and mood swings. (Hemat RAS 2003, page 38 and here). When magnesium is deficient, calcium can leak in soft tissue and cause damage – that is calcification. Mark Mayer p15

The function of adrenaline is to convert sugar stores in our body in the form of glycogen into glucose.(See image)

The reason for this is that brain is very sensitive to glucose levels. Although the brain represents only 2 per cent of the body by weight it requires about 60-70 per cent of available glucose in the body to energize the biochemical machinery of brain cells. (Stryer 634).

Glucose is the forerunner of Biological Energy called (ATP), which is essential in the manufacture of the relaxing and feel good neurotransmitters, such as serotonin.

Thus when the brain (in fact the HPA axis) senses a low blood sugar level it will send an hormonal message to the adrenal glands to pour adrenaline into the system. This raises blood sugar level and will feed the brain again, but it also causes us to feel fearful without an external object of fear. The fear is irrational.

Adrenaline not only activates the SNS, but is also a focusing hormone, forcing us to focus on any possible “danger” at the expense of anything else. It causes us to “ruminate”. Thus excess adrenaline production also lies at the root of Obsessive Compulsive Disorder (OCD) and Post Traumatic Stress Disorder (PTSD).

Thus now the question is why is the brain starved of energy causing it to trigger stress hormones??

There are many reasons for this, because there are many medical conditions that interfere with the proper absorption of glucose, such as the various digestive disorders, heavy metal intoxication replacing zinc substrates, coeliac disease, Crohn’s Disease and Ulcerative Colitis, hypothyroidism and hyperthyroidism. The list is unending.

However the majority cases of of energy starvation in the brain is due to Insulin Resistance, which blocks the transfer of glucose (and other nutrients) across cell membranes. This can lead to the hypoglycemic syndrome, with its multitude of psychological and physical symptoms.

This condition can be tested with the four hour Medical Test for Hypoglycemia. It can also be tested with the Nutrition Behavior Inventory Test (NBI) and the Hypoglycemia Questionnaire. If you score high you are likely to be hypoglycemic.

The non-drug treatment of this condition is going on a Hypoglycemic Diet.

This goes to show that the various forms of mental illnesses (really brain diseases) are due to a Nutritional Disorder.


Stryer, Lubert (1988), BIOCHEMISTRY, WH Freeman and Co, NY

Treatment of Bipolar Disorder
Bipolar disorder may be viewed as an imbalance between the sympathetic (energizing) and parasympathetic (relaxing) nervous system.
Acetylcholine is the major hormone that activates the Parasympathetic Nervous System, promoting states of rest and relaxation. It is formed from phosphatidylcholine with the help of vitamin B5 (pantothenic acid). Lecithin contains about 10-12% of phosphatidylcholine. People suffering from Bipolar Disorder may benefit from taking lecithin in the manic phase of the illness to counteract manic behaviour. 3 PubMed Studies, and PubMed Articles.  BUT this remedy should not be taken in the depressive stage of the illness. It has been suggested that the cycle of mania and depression in Bipolar Disorder can be moderated by controlling the manic phase, which over time may cause adrenal exhaustion leading to the inevitable depressive phase. By going on a hypoglycemic diet with megadoses of omega-3 fatty acids (fishoil) and supplementing the diet with choline (or lecithin) during the manic phase it is hypothesized that the depressive phase can be avoided. For Inositol depletion hypothesis, especially important in Bipolar Disorder and administration of lithium see EJ Nestler et als., 360. See 6 studies in support of omega-3 fatty acids for Depression and Bipolar Disorder. See also: here. See also: Research on Lithium and Bipolar Disorder.

In the depressive stage of Bipolar Disorder it may be worthwhile considering supplementing with L-phenylalanine (or Tyrosine) plus vitamin B6 (pyridoxine) which is decarboxylated to phenylethylamine (PEA) which has been shown to have an anti-depressive action in the brain. However, such supplementation or treatment should be under the strict supervision of a doctor or health care worker. Two Pubmed Studies. W Birkmayer et als.(1983), HC Sabelli, JI Javaid 1995, H Sabelli et als. 1996. See also M.R.Werbach summary of Bipolar Disorder here. For more nutritional therapies see: Alternative Mental Health.

See also at: Research Evidence for Hypoglycemia

Blushing – One source suggests: “The simplest method for enabling your para-sympathetic nervous system to lower anxiety is to use 7-11 breathing. This means you breathe in for a count of 7, hold briefly, and breathe out gently for a count of 11. No matter if you stick with the 7-11 count or some other combination, make sure the out-breath is longer than the in-breath. Practice the breathing technique in a quiet place, and then use it to calm a racing heart and cool a reddening face when you need it. Source

However, it should be realized that this is a Management Technique not likely to “cure” the underlying biochemical abnormality responsible for the symptoms.

It is also worthwhile to try out the Hypoglycemic Diet.

Please discuss this article with your health care worker, doctor or nutritional doctor or therapist.



Also try out taking LECITHIN to activate the Parasympathetic Nervous System as described above.


Arrhythmia or irregular heart beats should always be checked out with a doctor and can often be treated with supplementation with magnesium.

Also read:

Index to Specific Topics and Research

References to Mood Disorders and Nutrition

What is Hypoglycemia?

The Serotonin Connection.
Beating Anxiety and Phobias
Post Traumatic Stress Disorder and Hypoglycemia
Depression: a Nutritional Disorder
Depression: a Disease of Energy Production

36 Responses

  1. Jane Stringer says:

    This is very interesting ….. I have noticed that if I eat a hearty breakfast, my anxiety is much lower than if I hadn’t. I have been suffering with appalling anxiety following the birth of my second daughter, some eight years ago. I was diagnosed with post traumatic stress and agraphobia (sorry about the spelling) shortly after her birth. I was unable to leave the home and spent all day in a high state of anxiety. Following loads of different pills and ending up on diazapham I finally got to see a guy for CBT. This was the turning point for me. Four years later, I returned to teaching but last year had a relapse and quit my job, then got burgled etc… I now seem to have fallen back into those horribe habits.. Can’t go out, mornings are worse, forever taking my pulse as my heart races a lot of the time an just feel panic until my girls and husband get in and then it’s almost like a switch, and I feel fine and I feel I can go out etc… any suggestions other than take tablets, as I will never go back to them.

  2. Jurriaan Plesman says:

    Hello Jane,
    II is sad to hear what you had to go through. I believe that hypoglycemia is a major factor in your anxiety and Post Traumatic Stress Disorder (PTSD). 
    I suggest that you test yourself with that NBI  and HYPOGLYCEMIA QUESTIONNAIRE at:
     If you score high I suggest you go on the Hypoglycemic Diet (look up) and see how you go. 
    Also look up GLYCERINE which is a supplement that may help you relax. Of course the latter is not a cure. You should improve within a couple of months or maybe even a few weeks. 
    Apart from hypoglycemia there could be allergies that can cause problems. Look up ALLERGIES at this web site. Dr George SAMRA has written articles and a book on that. Also see TESTING FOR ALLERGIES. 
    If there is no improvements, there may be other diseases playing a role. Please read;
    and discuss with a Nutritional Doctor. Look up
    LOOKING FOR ALTERNATIVE DOCTORS if you want to see a Nutritional Doctor. 
    Please let us know how you getting along?

  3. Ron Langley says:

    I am 68 years old and have suffered from skipped beats for a bout 4 decades. About 2 years ago I started taking a product called Natural Calm ( MG ) . Even though my skips still occur I am about 90% better and if I don’t take mg 3 times a day I really have skips, ( maybe even more than before ) What’s you take on this. Thanking you in advance..

  4. Jurriaan Plesman says:

    Irregular heart beats are symptoms of many diseases, but it is very well known among nutritional therapists that magnesium plus calcium can stop irregular heart beats, reduce high blood pressure and so on. 
    Nevertheless, I still would advise to check up with a doctor (preferably a nutritional doctor) the exact nature of irregular heart beats. It could be atrial fibrillation which can have many other complications that needs attending to. 
    That you feel better is a good sign, but I would still suggest that you should seek the approval of a nutritional doctor. 

  5. Debbie DeRoma says:

    I have Mitral Valve Prolapse. After reading this I realize so many things that has happened to me before that would react and I would have a sense of my heart jumping up into my throat.. I was diagnosed with Mitral Valve Prolapse. But I also have things happen at different times also that sounds like Sympathetic Nervous System . Like during stressful times I become very Baloaded and sometimes when I have fear I get the shivers and shake like I am freezing..I have Anxiety, from time to time, my heart races and I am Hyper active..Sometimes i get so stressed out I feel like I cant swallow..but then I have to talk my way out of these feelings..I have to keep my self away from things I fear..and I am forever being cautious about my surroundings..There are reasons I have these reactions, but how do you diagnose Parasympathetic Nervous System . I have been this way since I was 5 years old when I had “Post traumatic Syndrome.I also cant sit still, restless, .do I go to a MD? Does it sound like that is what ales me ? I dont want meds, never have..but magnesiem will help? I have lived with this since I was 5 and feel hopeful I have a answer now..

  6. Jurriaan Plesman says:

    I suggest that you adopt the hypoglycemic diet and see if it helps reduce symptoms. Please discuss with your doctor.

  7. Serges says:

    Hi, I have experienced fear for as long as I can remember. It make my life very difficult and excess adrenaline produced by my body give me stomach pains and back pains. I can’t answer a single question in class and socialisation is very difficult. Although I would like to, I don’t do it. I score the highest in your questionnaires and it seems as the questionnaire is directed to me. Please help me with your suggestions.

  8. Niraj Pandey says:

    Now I am 18 years old boy. About 7 months ago I went to play National Cricket Tournament. For the first time, there I think my heart beats faster than previously i noticed, may be due to fear. But when I returned from there I didn’t find my body was functioning well it was because I noticed my body wasn’t active as it used to be as well as some sort of hang over in my head. Also, my heart beat faster so i consult one of the doctors related with HEART. He advised me to take INDERAL 10(name of medicine) for over a month but it didn’t work properly. Later on the same doctor suggested me to consult a doctor related with nervous system. He told me that you should take medicine for over a year. My second month is running after taking that medicine, i think it has reduced some sort of problem on me but still ‘breathing problem’ is with me and when i start to play something my heart starts to pound faster. These all are my problems and now I want to ask you some question serially:
    1) Whether it will invite other serious kind of illness or not?
    2) Do you have any experience that this sort of ill people got better, if yes than how much time it will take to be well?
    3) What should I have to do to solve my breathing problem?
    4) Is this related with the nervous system too?
    Please answer me Detaille…………… I will wait for it

  9. Natalie says:

    I suffer from a shaking disorder, nerve related after witnessing my father having an eplieptic seizure. It was traumatic to watch and since then I have suffered with tremours for 5 years, starting at age 16. I have tried all kinds of therapy, counselling, psychotherapy, hypnotherapy & I’m hopefully being referred soon for CBT. In the mean time I have been undergoing chiropractic treatment. This seems to have been the only treatment to actually have made a diffence. However, I’m still open to other ideas/suggestions if anyone has any. Is there anything else anyone can suggest?


  10. Sarah says:

    An American book on mood disorders states that Glutamine powder can be taken to treat hypoglycaemia, as it supplies the brain with energy and lowers blood glucose levels. Do you agree? Thank you!

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