The Role of the Autonomic Nervous System in CFS/ME

March 9, 2020



One of the key components in understanding Chronic Fatigue Syndrome / ME is to understand the role of Autonomic Nervous System (ANS) and how an altered or dysfunctional ANS may be creating and/or exacerbating the symptoms associated with CFS/ME.


The Autonomic Nervous System is a part of the Nervous System that controls and regulates our body’s internal organs without any conscious recognition or effort by us. It has influence over muscles and glands throughout the body and controls a range of functions such as heart rate, breathing, salivation, digestion, perspiration and urination.


The ANS comprises two antagonistic sets of nerves: The Sympathetic Nervous System and the Parasympathetic Nervous Systems.


When our brain perceives a threat, the Sympathetic branch of our Nervous System kicks in, pumping blood to our muscles/heart/brain so we are ready to fight or run for our lives - often referred to as the ‘Fight or Flight’ mode.


When the threat has passed, the Parasympathetic branch of the Nervous System kicks in to calm everything down - often referred to as the ’Rest, Heal & Digest’ or ‘Feed & Breed’ mode.


In healthy, low stress, individuals this switching between the Parasympathetic and Sympathetic Nervous Systems works synergistically via a mechanism called The HPA Axis (The Hypothalamic/Pituitary/Adrenal Axis) which operates on either increasing or decreasing feedback loops which either stimulate or inhibit the release of certain stress hormones in particular, Cortisol.


In chronic stress however, the HPA Axis can become desensitised to the calming effects of the Parasympathetic Nervous System leading to Sympathetic Nervous System Dominance and adrenal overload resulting in the physical, mental and emotional exhaustion experienced in CFS/ME.


Whilst this 'Fight or Flight' mechanism is life saving in the short term, in the long term it can create all sorts of havoc in the body. If we are running or fighting for our life then our body is focusing all its efforts on pumping blood to our muscles, heart and brain. Intelligently, it is not going to waste any energy on body functions that do not matter - a properly functioning  digestive, immune or reproductive system is completely irrelevant at this time. Therefore, Sympathetic Nervous System Dominance will lead to an imbalance in many of the body's systems via either an up or down regulation and this is why we see such a wide-ranging number of random symptoms in CFS/ME.


Getting out of Sympathetic Nervous System Dominance is crucial in order to get symptom reduction and also to allow the body to rebalance and regain its natural levels of homeostasis - only then is the body in a state where it can start to heal.

What can we do to get out of Sympathetic Nervous System Dominance

  • Eat a diet that supports healthy blood sugar levels & does not increase Cortisol production

  • Identify and correct nutritional deficiencies

  • Identify and support the body systems most out of balance

  • Improve sleep quality

  • Learn tools / techniques that can lower our anxiety and stress response

  • Identify and break negative behavioural patterns that drive us into 'fight and flight' mode

  • Deal with unprocessed trauma / grief that can be driving a negative stress response

  • Identify and correct digestive problems such as gut dysbiosis and gut permeability

So with the endemic levels of stress we all experience, why isn't everyone tipping over into CFS/ME? Well genetics will play a role in a predisposition to this illness. There is interesting research around the 'highly sensitive' personality and the sensitive gene which shows some people are hard-wired to process and react to stress differently to most other people.


A common denominator I see with all my CFS/ME clients is a Type A personality: The Over Achiever, The Perfectionist, The Worrier, The Helper. These personalities tend to be self-critical with very high expectations of self, endless 'To Do' lists, their minds are always processing, thinking, worrying, strategising and they find it more challenging to shut off. Awareness around these energy depleting personality subtypes is also important in changing behavioural patterns that might be driving a negative stress response.


As can be seen from the above taking a multi-faceted approach, way beyond nutrition, is essential in supporting this very complex and multi-faceted condition.




Cvejic, E., Sandler, C.X., Keech, A., Barry, B.K., Lloyd, A.R. and Vollmer-Conna, U. (2017) Autonomic nervous system function, activity patterns, and sleep after physical or cognitive challenge in people with chronic fatigue syndrome, Journal of Psychosomatic Research, 103, 91-94.


Fisher, J.P., Young, C.N. and Fadel, P.J. (2010) Central Sympathetic Overactivity: Maladies and Mechanisms, Autonomic Neuroscience, 148 (1-2): 5-15.


Johnson, C. (2017) Chronic Fatigue Syndrome Studies link Autonomic Nervous System Problems to the Brain, HelathRising Available: syndrome-link-autonomic-nervous-system-problems-to-brain/


Martinez, M., Mora, T., Vargas, A., Fuentes-Iniestra, M., Martinez-Kavin, M., (2014) Sympathetic nervous system dysfunction in fibromyalgia, chronic fatigue syndrome, irritable bowel syndrome, and interstitial cystitis: a review of case-control studies, Journal of Clinical Rheumatology, 20, 3: 146- 50.


Orjatsalo, M., Alakuijala, A. and Pertinen, M. (2017) Autonomic Nervous System Functioning Related to Nocturnal Sleep in Patients with Chronic Fatigue Syndrome Compared to Tired Controls, Journal of Clinical Sleep Medicine.


Robinson, L.J., Durham, J., MacLachlan, L. and Newton, J.L. (2015) Autonomic function in chronic fatigue syndrome with and without painful temporomandibular disorder, Fatigue: Biomedicine, Health and Behaviour, 3, 4.



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