The autonomic nervous system (ANS) is the branch of the nervous system that automatically regulates the function of our internal organs and numerous bodily functions, such as breathing, heartbeat and digestion. These processes all occur without our conscious effort. The ANS is a complex network that helps maintain physiological homeostasis, or internal balance.
The ANS is divided into two branches that have similar names: the sympathetic nervous system; and the parasympathetic nervous system. Whenever the nervous system receives information about what is happening in and around the body, it can respond either by stimulating (sympathetic) or inhibiting (parasympathetic) various functions.
Think of the ANS as being similar to a car. The sympathetic nervous system is like the accelerator of the car, speeding us down the highway of our busy lives. The parasympathetic nervous system acts as the brake, allowing us to stop temporarily at stop signs and red lights. Going to bed at night is the equivalent of putting the car in the garage and turning off the engine.
The sympathetic nervous system, which prepares the body to respond quickly to an emergency, has been described at the “fight or flight” response. When activated, these are some of the bodily changes that occur:
The parasympathetic nervous system helps the body recover after activation and to conserve its energy. It has been called the “rest and restore” branch, because it allows the following changes in physiology:
So how can the ANS affect our health? Imagine what would happen if you kept your foot continually on the accelerator of your car without using the brakes. When our nervous system stays alerted for long periods of time, as occurs with chronic pain and high stress, our health is negatively impacted. Past traumatic experiences, as well as our hectic lifestyle, can also create this hyper-alerted state. Survival mode kicks in and we may find it very difficult to shift out of this high gear, possibly resulting in anxiety and insomnia.
However, engaging the parasympathetic nervous system allows the body to downshift and “brake”. This is the essential part of our nervous system that maintains our health and promotes the body/mind’s healing capacity. That is why many holistic/integrative therapies focus on this part of the ANS.
Yoga therapy practices, especially breathwork and mudras, can be used in daily life to pause and put our foot briefly on the brake. And Reiki Therapy is very effective at gently activating the parasympathetic nervous system, to allow the body to rest and restore balanced function.