The Autonomic Nervous System and Your Health

Allow me to get something off my chest. You will not necessarily be healthy if you diet and exercise. Contrary to popular belief, not all diets and types of exercise are the same. Doctors remind me that they do not understand this concept whenever I see a patient who is overweight with chronic pain. They all comment on how their doctors tell them that their condition would be better if they “just ate less and exercised more”. “Try walking”, they say, even though their patients have pain when they walk. I am also reminded that most people do not get this concept when I go to my local Gold’s Gym where the majority, if not whole, membership is hell-bent on the bodybuilding mentality where bigger muscles and less visible body fat equates to better health. Meanwhile, the people with the “great” bodies have so because 1) great genetics, 2) they’re younger and have greater recovery abilities and have raging hormones to the point that any weight training program (no matter how good or bad) will get them results (ie. teenage males), 3) drugs, or 4) optimal health through proper nutrition for their individual biochemistry, appropriate balance of the catabolic (breaking down) effects of exercise and the anabolic (building up) effects of rest, adequate hydration, and ideal lifestyle habits (all of which is a rarity in most health clubs). Although the last reason is not the norm, it can be if people understood the influence of the Autonomic Nervous System on their health. Understanding that we can not directly control the Autonomic Nervous System but can indirectly influence its effect on not just keeping us alive, but keeping us alive longer and feeling great.

To back up a little bit, let us review the general scheme of the nervous system (see Figure 1).

We are all familiar with the Central Nervous System (CNS), which consists of the brain and spinal cord. The CNS is the headquarters, or high command center. It integrates, processes, and coordinates sensory data and motor commands and is responsible for things like intelligence, memory, learning, and emotions. The other major half of the nervous system is the Peripheral Nervous System (PNS). It is basically everything outside of the CNS. It provides sensory information to the CNS and carries out its commands to peripheral tissues and systems. There are two major divisions of the PNS, the afferent division and the efferent division. The afferent division brings sensory information to the CNS and the efferent division carries out the motor commands of the CNS to muscles and glands. The efferent division is divided into the somatic nervous system and the autonomic nervous system (ANS). The somatic nervous system allows for conscious, or voluntary, control over skeletal muscle (skeletal muscle being the muscles that move us). The autonomic nervous system is responsible for unconscious, or involuntary, regulation of smooth muscle, cardiac muscle, and glandular activity, or secretions. It is automatic and does not require conscious thought. Basically, it is the backstage crew that keeps everything running smoothly. Things like respiration, digestion, and your heart beat, you know, important things like that.

The ANS is classically divided into the sympathetic and parasympathetic nervous systems. More recently, a third branch is being identified as the enteric nervous system.

The sympathetic branch is the popular “fight or flight” nervous system that prepares the body to either “fight” or run away from danger. It is a survival mechanism. Blood is shunted away from your internal organs and directed to the muscles to do their job. This branch is considered to be catabolic since it breaks down your nutrient and hormonal reserves and with prolonged activation can cause tissue wear and tear. When the sympathetic nervous system is dominating, the following may occur:

Poor digestion

Constipation

Increased respiratory/heart rate

Night sweats

Waking unrested

Jittery

Increased inflammatory conditions

Decreased salivation

Anxiety

Poor sleep quality

Orgasm/genital inhibition

Nervousness

Increased muscle tension

Increased suseptibility to infection

The parasympathetic nervous system is antagonistic to the sympathetic and is considered the “rest and digest” branch. It is responsible for digestion, elimination, immune function, and growth and repair processes. It normally predominates when we sleep at night, a time when our immune system is very active in order to restore our bodies. I often refer to this branch of the nervous system as the “de-stressing” branch. When the parasympathetic is dominating, the following occurs:

Strong and excessive digestion

Incontinence

Decreased respiratory rate

Poor sleep quality, hibernation

Nervousness, depression, somnolence

Increased gag reflex

Increased male erections

Hyperactive bowel, colicky

Orthostatic failure upon rising

Decreased perspiration

Mucus secretions

Hands warm and dry

Increased WBC count and greater allergies

The newly recognized enteric nervous system is considered our body’s second brain. This is because about half of our bodies’ nerve cells are located in the gut. There is actually more nerve cells here than there are in the spinal cord. Also, every class of neurotransmitter (chemical substance that facilitates communication among nerve cells, as well as from nerves to muscles, glands, and vessels) found in the brain is also found in the enteric nervous system. Another interesting fact is that the enteric system has bi-directional control and communication with the body’s major control centers (such as the sympathetic, parasympathetic, CNS, PNS, and endocrine system). What this all means is that there is literally a mind-gut connection. We’ve all heard of someone who has developed ulcers due to excessive stress; or the term “gut feeling” referring to the intuitive sense some may have; or how about the condition Irritable bowel syndrome? Why do you think the bowel gets to be so irritable? Also, since the gut has its own nerve cells, it can do a lot of things without input from the brain or spinal cord and thus conscious thought. When you feel pain, heartburn, gas or diarrhea, this is your gut’s way of “sounding the alarm”. Unfortunately, most people do not listen to this “alarm” and disregard it as “normal”. When the gut can not take it anymore, more symptoms arise and the usual scenario of “what drug can I take for this now?” occurs. Ironically, the usual drugs taken cause more harm in the long run.

To summarize, if you have excessive sympathetic-dominance occurring in your life, your insides may feel as if an animal is chasing you all day long, leading to suppression of the parasympathetic nervous system and thus a decreased ability to recover and at the same time your gut functions begin to deteriorate which can affect just about every other system in your body and you begin to wonder why you have such anxiety and depression and lack of energy!

The Nutrition and Lifestyle Coaching Program at JSC addresses any imbalances in one’s autonomic nervous system through diet, lifestyle, and exercise modifications. People need to understand there are no permanent quick-fixes in life. What you do and think on a daily basis affects your health.

Resources:

Martini, F. Fundamentals of Anatomy & Physiology, Prentice Hall, 1992

Watson, B., Smith, L. Gut Solutions, Renew Life Press, 2003

Chek, P. Balancing the Autonomic Nervous System, The CHEK Report, v4 Spring 2004

CHEK NLC Level I Manual, C.H.E.K. Institute, 2001

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