Functional Training for the Nervous System

Functional Training for the Nervous System

Author: Noah Kennedy-White

Remember the last time a sabre-toothed tiger tried to pull your family out of its cave? Remember the reaction your body had - full on adrenaline, grab the clubs, swat like crazy until your progeny was out of harm’s way, and then slowly calm down...No? How about the last time you forgot to breathe? Or the feeling before you stepped on the platform, in the thrower’s circle, or had to give a presentation at work?

Whether you realize it or not, your autonomic nervous system (ANS) is constantly active, helping you get through each day by moderating your breathing, heart rate (HR), metabolic priorities, and about a thousand other unconscious processes. The ANS is generally considered to be split into two components: the Sympathetic and parasympathetic nervous systems. The sympathetic nervous system (SNS) generally garners more attention, and you may know it as the system that controls the fight-flight reaction for stressful situations (ol’ sabre-tooth). 

The SNS does things like increase HR, push blood away from your core organs toward your muscles and extremities, and dilate your pupils, all of which are done for maxim physical performance1. You may have noticed these physiological reactions the last time you were stressed or scared. Most of the nervous system focus in sports performance leans toward the SNS side of the ANS equation, since we all want to get hyped up for a big lift or competition. Smelling salts, loud music and pre-workout are all designed to jack up your sympathetic nervous system and get your body ready to mobilize power and focus quickly. But what about the parasympathetic system? Just as training can be split into activity and recovery, focusing on the PNS and SNS can help maximize your gainz.

Much like the general maxim of the SNS is summed up by “fight or flight,” the parasympathetic nervous system (PNS) is often boiled down to “rest and digest.” The PNS primarily innervates the head, neck, and the organs of the abdomen and pelvis via the vagus nerve2. The vagus extends from its origin in the brainstem through the neck and the thorax down to the abdomen. Because of its long path through the human body, it has also been described as the “wanderer nerve.” This link is important for our ability to effectively digest food, as well as control heart rate, which is a powerful biological correlate of stress. Studies have even shown that if you have an imbalanced ANS, your SNS can take over, negatively impacting both sleep quality and duration3. If we spend lots of time firing up our sympathetic response, it’s important that we also enhance our parasympathetic tone, giving our bodies and minds a chance to recover and actually grow from all of the work we put in. 

Thankfully, there are a ton of ways we can activate the PNS, which will counteract SNS tone and help us improve recovery. Remember the vagus nerve, the primary nerve pathway of the parasympathetic nervous system? Most of the nerve fibers of the vagus are what are called “afferents,” or nerves that project into the brain, rather than away from the brain. What this means is that one of the most powerful ways to increase PNS tone is by stimulating your body in the right ways. Deep diaphragmatic breathing, stretching, and light massage are all ways to increase PNS tone via touch, thereby calming both the body and the mind4. Further, the soft, pointed focus of meditation or the breathing and cold exposure exercises taught by Wim Hof are excellent for cultivating this calmness in the mind and the body. Even activities as simple as singing, playing an instrument, or listening intently to sound can effectively draw down sympathetic activation and bring our nervous system toward a more restful, healing state5. I think the connection between the body and mind here is very important to note. Neither operates in a vacuum without the involvement of the other, and what impacts one impacts the other. If your chest is tight and your breathing is short and shallow, your body is primed to be stressed instead of loose and relaxed.  


Now you know the two principal pathways of the autonomic nervous system. The sympathetic nervous system primes our bodies for activity; the parasympathetic nervous system helps us relax--physically and mentally--and recover from that training. It’s also important to remember that stressors that may activate (or overactivate) the sympathetic “fight-or-flight” response are not limited to training. Work, consistently poor sleep, and chronic over-caffeination (at least one coach in particular comes to mind) can all add to the mental and physical stress that you feel. You have to be able to take this into account when you’re considering how much you need to recover, and how you want to go about it. Sitting and taking a few minutes of slow, deep breaths, relaxed stretching, and even a relaxing evening with friends or family can all help activate your PNS and set you up to recover well. Next time you feel that stress of a plateau or feel “overtrained,” sit your butt down, take some deep breaths and stretch it out!


  1. Furness, J. B. (2009). Parasympathetic Nervous System. Encyclopedia of Neuroscience, 445–446.
  2. Jagmeet P. Singh, Jagdesh Kandala, A. John Camm, Non-pharmacological modulation of the autonomic tone to treat heart failure, European Heart Journal, Volume 35, Issue 2, 7 January 2014, Pages 77–85,
  3. Castro-Diehl, Cecilia, et al. “Sleep Duration and Quality in Relation to Autonomic Nervous System Measures: The Multi-Ethnic Study of Atherosclerosis (MESA).” Sleep, vol. 39, no. 11, 1 Nov. 2016, pp. 1919–1926,, 10.5665/sleep.6218. Accessed 15 Mar. 2019.
  4. ‌Fallis, Jordan. How to Stimulate Your Vagus Nerve for Better Mental Health. 17 Jan. 2017.
  5. Porges, Stephen W, and Deb Dana. Clinical Applications of the Polyvagal Theory : The Emergence of Polyvagal-Informed Therapies. New York, W. W. Norton & Company, Inc, 2018.

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