Greater Life Chiropractic

Sympathetic & Parasympathetic Responses

Share on facebook
Share on google
Share on twitter
Share on linkedin

The sympathetic nervous system is best understood as the fight or flight response, while the parasympathetic nervous system is best understood as the rest and digest response. Both of these systems fall under the umbrella of the autonomic nervous system, which is part of the larger central nervous system. Both systems control your viscera, or your insides, but they elicit very different reactions.

You likely know that the central nervous system includes your brain and spinal cord, as well as the 41 miles of nerves within your body. You may even know that the autonomic nervous system is responsible for controlling non-voluntary actions, such as breathing, digesting, and pumping blood throughout your body.

But do you know what the significance is between parasympathetic and sympathetic responses? And do you know why they matter? Read on to learn more about how your body works and how to optimize its function and your overall health.

Fight or Flight: Sympathetic

The sympathetic nervous system is essentially your body’s emergency response system. When a threat is perceived, it kicks into gear by preparing the body to expel energy and protect itself. It focuses on your fight or flight responses by shutting down other non-emergency systems, like digestion, and sending energy to other systems that will protect you. A sympathetic response includes an increased heart rate, increased blood pressure, pupil dilation, widening of bronchial passages, and sweating. It also makes more glucose available for energy, all in the name of preparing your body to protect itself. All of these reactions are involuntary—you don’t have to think about any of them to make them happen.

Rest and Digest: Parasympathetic

The same internal organs that have sympathetic responses in the face of danger are affected by parasympathetic responses in other situations. This “rest and digest” response is focused on maintaining homeostasis to ensure long-term health and proper restoration of body functions. Homeostasis is a state of balance that is vital to proper function of your body. The cells within your body depend on certain things, like oxygen and dissolved food, moving into and out of cells. These processes of osmosis and diffusion require a state of homeostasis, which can only be achieved when sympathetic responses are not present. The parasympathetic nervous system strives to conserve the body’s energy when no threat is near. It monitors and regulates body processes that are vital for a healthy life, including digestion (including urination and defecation), sexual arousal, crying, and salivating.

Complementary Systems That Help You Thrive

While the parasympathetic and sympathetic nervous systems are considered oppositional, they actually work together to make your body function better and be as safe and as healthy as possible. Since all of the sympathetic and parasympathetic nerves that initiate these responses originate in the spinal column, it is incredibly important that your spine is properly aligned. If you have a misalignment in your spine, the nerves that affect these important systems can be compromised, resulting in less than optimal function and inappropriate responses to external stimuli. If there is a lack of balance between the parasympathetic and sympathetic systems, you may experience unnecessary amounts of sympathetic responses, leading to anxiety, fatigue, and decreased health.

Charlotte chiropractor Dr. Grant would love to help you reach optimal health and body function through principled chiropractic care. His team at Greater Life Chiropractic can set up a consultation for you to learn more about your autonomic nervous system and why chiropractic can change your life.

Contact us

Find our location


Gibbons, P.F., Gosling, C.M., Holmes, M. “Short-Term Effects of Cervical Manipulation on Edge Light Pupil Cycle Time: A Pilot Study.” Journal of Manipulative and Physiological Therapeutics, 2000 Sep; 23(7): 465-469.

Welch, A., Boone, R. “Sympathetic and Parasympathetic Responses to Specific Diversified Adjustments to Chiropractic Vertebral Subluxations of the Cervical and Thoracic Spine.” Journal of Chiropractic Medicine, 2008 Sep; 7(3): 86-93.



More Articles

Call Now
Schedule Online