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Our nervous system is the foundation to our health and wellbeing. It coordinates and controls all our bodily functions, movements, thoughts, emotions, and is constantly monitoring our environment both inside us as well as all around us. Its what allows us to engage and enthusiastically take part in life, or leads us to shelter when we feel a need to rest, recuperate, or protect ourselves. How does the nervous system do this and why is it important to understand? Understanding empowers us to better utilize the tools our body possesses in order to express optimal health and well being, positive social interaction, mental fortitude, and recovery from illness and injury.

With all good conversations about the nervous system it needs to contain information about anatomy. Anatomy can seem daunting or tedious at times, but it provides us a map to better navigate the vast information highway that is the nervous system. By providing names and knowing the junction points of that map we are able to bring awareness and utilize that knowledge to promote health and well being.

The area of the nervous system for this discussion is our autonomic (automatic) nervous system or ANS. I had briefly touched on its balancing act in a previous post. We laid out a split in the ANS of sympathetic and parasympathetic divisions. Here we are going to break down that simplicity and reconstruct the ANS divisions’ complex interactions. Our ANS is actually divided into three major sections that interact and interweave to monitor our environment and provide our body with many of our unconscious functions. Those sections are known as the Ventral Vagal, Sympathetic, and Dorsal Vagal systems (known in research as the polyvagal theory devised by Stephen Porges). The ventral and dorsal vagal systems combined to form the parasympathetic system.

Polyvagal Theory

Our Ventral Vagal system is known as our social engagement system. It monitors our environment to determine whether or not we are safe. It also performs a function called the vagal brake where it helps restore equilibrium between the other two divisions. Safety is vastly important to our nervous system, and determining that a potential encounter in our world is safe allows us to fully engage in social interaction or take part in different activities. When the ventral vagal system determines a situation is unsafe then it shifts us to the sympathetic system. This is our mobilisation system as we either prepare our bodies for a fight or to run away (flight). The third option our ANS has is to utilize the dorsal vagal system, or our immobilisation system. The dorsal vagal system protects our vital functions and organs by freezing and preserving resources to keep us alive. It is important in monitoring and restoring homeostasis or baseline equilibrium in our internal organ systems. These systems can also be viewed as states of function, providing a baseline of calm, reaction, or protection in order to remain or return to safety.

 As much as we like clear cut ideas and concepts, the ANS is laid out on a sliding continuum of function and can transition state in milliseconds. In fact it needs to do this; being stuck in a prolonged sympathetic state or dorsal vagal state can have negative effects on our physical and mental health and well being. If we are constantly in a state of mobilisation this exhausts our bodies energy and can cloud our perception of our health and function, as well as effect our emotional state and how we interact with other people. A prolonged sympathetic state is one of chronic stress, poor sleep, exhaustion, anxiousness, poor heart, cardiovascular and gastrointestinal health. Conversely being stuck in a dorsal vagal state is one of isolation and immobilisation. It prevents us from interacting with others, lowers our physical function to the bear minimum to survive, exhausts our immune system and is representative of a depressive state. 

 Our ventral vagal or social engagement system prevents us from sliding too deeply or staying too long into these extremes of dysfunction, by acting as the vagal brake. Similar to a brake petal in a car or on a bicycle. When the brake is released it allows our body to accelerate into the sympathetic or dorsal vagal states in order to carry out its desired task. When that task is completed the brake is pressed to restore us to a state of calm and social engagement, once safety is determined or restored. 

By enhancing our ventral vagal system and our vagal brake we are able to promote neurological sense of safety which promotes all bodily and mental health and well being. The greatest measure of our ventral vagal function is known as vagal tone or heart rate variability. Having greater heart rate variability refines the control and creates precision of the vagal brake over the other two systems. Heart rate variability is the difference in heart rate as we breath in and out. As we breath in our heart rate accelerates, as we breath out it decelerates. This function can be trained, just like learning a new skill or activity. This can be done directly by breathing exercises, focusing on the movement of the diaphragm as we inhale and exhale. Simply by breathing out twice as long as we breath in helps improve the internal rhythm of our heart and syncs it with our lungs, creating a sense of calm and safety that has far reaching positive impacts on all our bodily systems. 

Understanding the role our nervous system plays in our health and well being assists us in recovery from illness and injury. It empowers us to interact with ours and empathize with others view points and reactions. It helps deal and adapt to the pressures and stresses of this world and the lives we lead. By promoting our own health and well being we are able to then go out and help others, creating a better world for all. 

The polyvagal theory also has important implications to our mental well being, recovery from trauma and the difficulties that arise from poor childhood attachment. For more information I would recommend viewing the work of Deborah A. Dana, Stephen Porges, Pat Ogden, Daniel Siegel, and Karen Treisman. If you struggle with mental health issues it is always recommended to consult a mental health professional for guidance.


by Nate Bogedain DC M.Sc

Nate is a chiropractor with a background in functional neurology and sports medicine. He has been helping people optimize their health and nervous system since 2014