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HEALTH CONCERN? BioHealth Health Concerns

Balancing the Autonomic Nervous System

Contributing Author: Chek, Paul H.H.P.

Paul ChekPaul Chek is a world-renowned expert in the fields of corrective and high-performance exercise kinesiology. For over twenty years, Paul’s unique, holistic approach to treatment and education has changed the lives of many of his clients, his students and their clients. By treating the body as a whole system and finding the root cause of a problem, Paul has been successful where traditional approaches have consistently failed. Paul is the founder of the C.H.E.K (Corrective Holistic Exercise Kinesiology) Institute, based in California, USA.
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Today, it is generally accepted that if you need to lose weight, want to put on muscle mass or are stressed out you need to hit the gym and hit it hard! While this approach did bear fruit in the past and became embedded in our consciousness as the way to do it, the realities of modern eating habits and lifestyles no longer support the use of an antiquated formula. To see proof of my point, one need only visit a public membership gym; there is no shortage of people who faithfully jog, run, pedal, pump, push and pull several hours a week, yet their body shapes change little, if at all! They get frustrated and their trainers get frustrated. It’s time we apply programming strategy appropriate for the 21st century.

The autonomic nervous system (ANS) may also be referred to as the automatic nervous system because it runs various physiological processes without any conscious thought. The ANS controls and regulates all the functions necessary to maintain life and, if we were to get knocked unconscious, it is our ANS that would keep us alive. Some of the key functions controlled by the ANS include:

  • Respiration
  • Blood pressure
  • Heart rate
  • Circulatory distribution
  • All organ functions, including digestion, detoxification and elimination
  • Immune regulation
  • Hormonal regulation
  • Thermoregulation, and more!

The ANS has three divisions, each having key functions. Let’s look at each of them briefly:

  • The Parasympathetic Nervous System (PNS), also called the anabolic, or rest, repair and rebuild nervous system, is responsible for digestion, elimination, and regulating repair of the body. The PNS also stimulates immune function at night during sleep and PNS function is closely linked to the timing and release of many key immune hormones and specialized immune messengers
  • The Sympathetic Nervous System (SNS) is often called the “fight or flight” nervous system because the SNS prepares the body to fight or to flee from danger. When the SNS becomes the dominant branch of the nervous system, blood is shunted away from the internal organs and into the muscles and periphery of the body to facilitate action. The SNS is also referred to as the catabolic nervous system because when it is active there is increased utilization of many nutrients and hormones and also greater tissue destruction is generally taking place. It is important to realize that when the SNS is dominant, the functions of the PNS are proportionately shut down. If this happens too frequently, many vital SNS functions become labored and vital PNS functions are relatively inhibited.

Figure 1
The SNS becomes dominant over the other branches of the ANS during exercise, physical labor or doing anything that requires delivery of blood to the muscles. A basic rule of thumb I teach is that if you are moving or exercising at a pace that would be uncomfortable after having eaten a large meal, your SNS will become stimulated and will take over. Relaxed movement with synchronized breathing, on the other hand, facilitates PNS activation and thus aids digestion. Another very important consideration today is that the SNS is easily triggered into action by stimulants, such as caffeine, processed sugar and a large percentage of medical drugs. You may want to think about that when we review the symptoms of excess SNS activity!

  • The Enteric Nervous System (ENS) is intimate with the upper digestive system, yet does have secondary fibers feeding lower digestive organs. The ENS is thought by many in the medical field to be a recent discovery, yet this is far from the truth. Byron Robinson, M.D. discusses the ENS in his book “The Abdominal Brain” which was published in 1899 (1). The second edition of his book published only a few years later, is still the most comprehensive book on the ENS to date (2). Among the many things that can be learned from a study of the ENS, we find that not only does the ENS contain as many neurons as the entire spinal cord (3) it has bi-directional control and communications with the body’s major control centers (Figure 2).

Figure 2
The greatest majority of the ENS neuron population resides within the small intestine as the myenteric plexus and submucosal plexus. This region of the body has intimate contact with all consumed foods, liquids and any of the toxins, chemicals or parasitic organisms that may enter during consumption. It is for this reason the ENS not only communicates to all major control centers, but may produce very powerful influences over mind, mood, circulation, energy levels, capacity for exercise and response to exercise. The enteric nervous system’s role in regulating our overall physiology, and even psychology, should make it clear to you that what you put in your mouth may be even more important than how you choose to exercise. After all, most people only exercise 3-7 hours a week (if that!), yet they generally eat three meals a day. When you consider that each meal influences your physiology for between 55-72 hours under normal conditions and you’re doing this at least three times a day, eating has a much greater capacity to alter your physical, mental and emotional capacity than exercise done only a few times per week! The days of personal trainers feeding their clients packaged and processed impersonations of food will have to come to an end if we are to help people in the new Millennium!


The ANS is a very complex system, yet there are some classic indicators of imbalance, or dominance of one branch over the others (Table 1).

The indicators in Table 1 can help the trainer or therapist ascertain the current status of the ANS in any given client. While the indicators presented help to highlight the characteristic dominant response of a respective system, it is important to realize that when any given symptom(s) become chronic, an ANS imbalance is suggested. For example, constipation is listed as an indicator of SNS dominance, yet this must be taken in context – when the SNS is dominant, as it will be during anything from a training session or playing tennis, you don’t want the antagonist functions of the PNS to dominate, which in this case would be incontinence or a hyperactive bowel! If on the other hand, your client suffers from constipation (moves less than 12 inches of feces daily on average or does not have a complete sense of elimination daily (4, 5)), this should be considered an indicator of excessive SNS tone.

Any time you see a client and want to determine the status of their ANS, run through the indicators in Table 1, the more indicators they present with, the greater the relative imbalance between the branches of the ANS. As a side note, the ENS communicates with and activates the SNS and PNS – thus, any dietary influences should be strongly considered as a potential stimulus to either branch of the ANS as mediated via the ENS. Although even just one indicator, when chronic, can indicate an imbalance of significance, it is generally reliable to assume that the greater number of chronic indicators you find, the greater the problem and the more critical it becomes to modify diet, exercise and lifestyle factors to encourage balance.


The first step toward balancing the ANS is to understand the common influences that create an imbalance. To do this we must look at the developmental structure of the human brain and nervous system.

Research in evolutionary biology, comparative anatomy and neurocognitive sciences has led to an understanding of what is now referred to as the Triune Brain (three brains in one), a concept that was founded and demonstrated by researcher Paul MacLean (6). As you can see in Figure 3, the reptilian brain represents the oldest brain structure that humans possess. Maclean describes the mammalian brain and neocortical, or human brain structures, as outgrowths of the reptilian brain. This is important to understand because many people misinterpret MacLean’s model thinking that the individual brain structures are modular, or independent of each other in function, which they are not. The best way to understand the triune brain system is to realize that the reptilian brain is like the operating system of a computer (e.g. MS Windows) – it is the platform upon which all the other computer programs operate. In this case, the other computer programs are the mammalian and neocortical brain structures.

As you can see in Figure 3, the reptilian brain is intimate with and inclusive of the ANS. We still have remnants of our developmental history as reptiles, and thus still maintain reptilian drives and behaviors. Reptiles (including the reptile in us!) have three primary drives, or concerns:

  • Safety: Before hunting or doing anything, a reptile’s primary concern is for his/her own safety. Reptiles are also very territorial and have a strong rank structure among them.
  • Sustenance: It only when the reptile’s safety is assured that it entertains consumption of food. Sustenance issues can range from having a lack of food to having to protect one’s food from others.
  • Sex/Procreation: The reptile only entertains sex/procreation after it knows it’s safe and has been fed for the time being. Because perpetuation of any species is a primal and genetically programmed drive of most living creatures, the inability to procreate would be considered stressful to most creatures, reptilian and otherwise.

Today, our clients present us with one or any combination of the following issues:

  • Safety, which generally relates to financial issues in most cases.
  • Sustenance relates to overeating, under- eating, eating incorrectly for your metabolic type (4,5,7,8) or eating poor quality foods that don’t deliver adequate nutrition and life-force.
  • Sex/Procreation today relates to any issue linked to inability to procreate (infertility, impotence) or sexual relationships (too much, too little, poor quality, inability to physically/emotionally connect).

The more of these reptilian stressors they have in their life, the greater the stimulus is to the SNS! At a very core level, these stressors are interpreted as being the greatest threat to our survival as a species – thus, the stress response is proportionate to the interpretation of the stressor in each individual. In other words, whatever someone’s perception is of any given stressor, the degree to which they feel stress towards that event will proportionately serve to stimulate the SNS. When looking at the number of SNS dominance indicators that are chronic (repeated regularly and exaggerated over weeks, months or years), we can interpret which one or combination of a client’s reptilian stressors are driving the system and just how stimulated, or over-stimulated, they’ve become.

While the collection and use of this information is much more vast than I’ve presented here, and is an important aspect of the CHEK Nutrition and Lifestyle Coaching Program as well as C.H.E.K Certification Levels 2, 3, and 4, the health or exercise professional reading this article can be of great service to their client by:

  • Suggesting educational resources to help them manage their reptilian stressors more effectively.
  • Modifying their exercise program to support balancing the ANS.


When you have a client who demonstrates multiple chronic indicators of reptilian stress (Table 1) and you have suggested books, tapes or counselors to help them better manage their specific stressors, you can further assist them with correct application of exercise.

A general rule of thumb I teach my students that if you can’t perform an exercise comfortably on a full stomach, that exercise is stimulating your SNS. With that in mind, you can now easily see how the majority of exercises being prescribed in a typical gym setting are serving to further stress the SNS; remember that SNS stimulation keeps the body in a catabolic state! If a client’s body gets stuck in SNS dominance in response to the combined stressors of their individual life, exercises that stimulate the SNS will only serve to perpetuate an already dysfunctional situation. In fact, I have had several clients over the years seek my consultation because, after hiring a personal trainer and exercising regularly, they gained weight… a pretty good indicator that the body interpreted the exercise as a threat to their survival.

If you or someone you know is training a client who has overly stimulated their SNS, I recommend that they focus on Chi-cultivating exercises until their ANS has been adequately balanced to respond to SNS challenges with an adequate PNS or anabolic rebound. Examples of Chi (life-force energy) cultivating exercises are introductory Yoga postures, Tai Chi, Qi-Gong or simply walking! In a number of cases where people were unsuccessful at changing their body shape or losing fat using a typical bodybuilding program, once they switched to a period of PNS stimulating (Chi-cultivating) exercise, along with the necessary diet and lifestyle modifications, their body changed favorably and rapidly! Not only were they able to improve their body shape and reduce body fat, they did it with far less time in the gym, which is music to a client’s ears given the schedules of most people today.

Just how much SNS stress an individual can take is specific to the individual. You may find that you can stick with one or two compound exercises such as squatting, deadlifting, cable pushing or pulling. Keeping the training sessions under 30:00 and supplementing their program with stretches that specifically restore muscle balance will also improve Chi (Life-force energy) flow in the body, thus facilitating ANS balance; to learn how to assess length/tension balance in the body, refer to The Golf Biomechanic’s Manual (9). When you see sleep quality, energy levels, mood and response to exercise improving along with a reduction of chronic SNS indicators you can carefully add more challenging exercises to their program, always being sensitive to the client’s day-to-day needs and overall stress levels. Some days it may be necessary to only stretch or cultivate Chi because they haven’t sufficiently recovered from the last workout. Monitoring your client’s digestion and elimination will also give valuable cues to their progress on your fitness program. (I expand on this more in my Flatten Your Abs Forever! video (5) and in my book How To Eat, Move, and Be Healthy! (4).


PNS over stimulation, or finding clients with chronic PNS dominance factors from Table 1, is very rare today. I may have seen only a half dozen in the past 10 years, most of which resulted from electrolyte deficiency. One of the primary indicators of PNS over-stimulation is orthostatic hypotension or, getting dizzy when rising from a seated to a standing position. The easiest first step to take in such cases is to add a pinch or two of unprocessed sea salt to each liter of water the client consumes for a few weeks. If that doesn’t address the problem, I suggest you consult a CHEK NLC Level 3 or a naturopathic physician for a comprehensive assessment and any needed program modifications. There is also a list of recommended people to consult with in the Resources section at the end of the article.


We must let go of the “no pain, no gain” philosophy! What worked with Navy Seals and football players no longer works for today’s gym members or the public. Because of the environment we live in today, we must change our philosophy about exercise and what it is to be healthy in the gym! Today, I personally believe that “pain = no gain”, and therefore we must “train, don’t drain!” We must remember that the reptilian brain is inclusive of the ANS and the key reptilian stressors are very real. Look not to see how much weight you can stack on the bar or leg press for your clients, but how much stress they have on their back each day on the job and at home. How are their finances (safety/security)? Is their diet adequate to improve life-force (sustenance)? Are they having meaningful, fulfilling sexual relationships? While these issues may seem a long way from a barbell, one need only stand in a gym for 20 seconds with two ears open and you will learn quickly that these issues can be heard in many conversations in the gym. As trainers and therapists, we were given two ears and one mouth so that we could listen twice as much as we talk and when we begin to listen to our clients, we will better understand their needs and realize the need to design eating and lifestyle programs to help them accomplish their goals most effectively – not just “hammer them” with the latest trends!

Please join me and my fellow C.H.E.K Practitioners, CHEK NLC’s, CHEK Exercise Coaches and Golf Biomechanics in building a health and vitality consciousness in the exercise and health care industries today! And remember, you are your best form of advertising for your programs, so the first place to start is always with yourself!
Toward Health and Vitality,
Paul Chek


  • Robinson, B. The Abdominal and Pelvic Brain with Automatic Visceral Ganglia. The Clinic Publishing Co., 1899.
  • Robinson, B. The Abdominal and Pelvic Brain. F. S. Betz, 1907.
  • Benteen, T. Personal Communication.
  • Chek, P. How to Eat, Move, and Be Healthy!. C.H.E.K Institute, 2004.
  • Chek, P. Flatten Your Ab’s Forever. C.H.E.K Institute, 2003
  • Gerald, E., Cory, A. Jr., Gardener, R. Jr. The Evolutionary Neuroethology Of Paul MacLean – Convergences and Frontiers. Praeger, 2002
  • Wolcott, W. Metabolic Typing Diet. Doubleday, 2000.
  • CHEK NLC Level I Manual, C.H.E.K Institute, 2003
  • Chek, P. The Golf Biomechanic’s Manual. C.H.E.K Institute, 2001.