I like to illustrate the sympathetic nervous system by yelling “FIRE” before coming in to teach my physiology students. Yes, indeed, in a one-word definition the sympathetic division yells, “FIRE!” The sympathetic nervous system operates in emergencies—which happens everyday. Stress of any kind activates it. The well-known “fight-or-flight” response when confronted with sudden fear or a stressor is caused by increased activity of the sympathetic nervous system. Effects of stimulation to this system include:

  • A rapid heart beat
  • Increased blood pressure due
  • Slowed digestion
  • Digestion is impaired by slower peristalsis
  • Increased blood pressure
  • Enhanced mental activity


Excessive sympathetic nervous stimulation promotes arteriosclerosis in several different ways. For example, it makes the blood vessels stiff and reduces the capacity of the blood vessels to dilate in other ways. All of these factors increase the risk for hypertension and arteriosclerosis. But that is not all; sympathetic nervous stimulation reduces the threshold for the development of electrical disturbances in the heart rate and rhythm. An overactive sympathetic nervous system also promotes inflammation throughout the body that contributes and sustains chronic diseases. Overeating also increases sympathetic outflow to the kidneys, heart, skeletal muscles, and blood vessels.

The Balancing Act

The parasympathetic nervous system involved in the activities of daily living under normal, everyday conditions—the non-emergencies if you like. It has the effect of doing the opposite of the sympathetic system. The pupils constrict, as do the bronchioles, the heart rate slows but the secretion of digestive juices and processes increase, and bowel and bladder can empty. For health we need a balance between these two systems.

Mental Stress Is Not The Whole Story

An overactive sympathetic system with possible underactive parasympathetic nervous stimulation is commonly seen during sleep deprivation and overeating and in the following conditions: obesity, fibromyalgia, metabolic syndrome, and elevated lipids (elevated cholesterol, LDL, and triglycerides). Fibromyalgia is an increasingly recognized chronic pain illness, characterized by widespread musculoskeletal aches. The metabolic syndrome is a condition characterized by four of the following: obesity (including pot-belly fat), high blood pressure, high blood lipids, reduced ability to handle glucose, inflammatory problems, and increased risk of forming blood clots. Individuals who have these problems especially need to learn how to reduce stress. Even survivors of heart attacks who have reduced parasympathetic tone are twice as more likely to die than those who have normal parasympathetic tone.

A Major Stress Buster

I would like to introduce the first great principle of stress-busting relief this way. I live in a rural county in Georgia, USA. Dade County is remarkable at hosting a wide variety of individuals. We have our share of intellectual individuals and red necks. About 20 years ago I was assisting a teacher here named Mrs. Brown in a small country school. That particular year we had fifteen students with sixty-six personalities. Now, Mrs. Brown was something else. In her younger days, a definite ‘Southern Belle‘—good looks, poise, winsome with a lovely soprano voice – she seldom became ruffled under stress. Well, for several weeks we had detected the strong odor of a dead animal wafting around the classroom. We looked for it but, after thorough searching, couldn’t find it and so concluded it must be somewhere outside under the dense foliage in the nearby woods that lay directly behind the school. And so the odor persisted when on a particular spring day, I returned to the school. Unfortunately, I had left my keys to the school at my house and, finding the school door locked, I knocked. Shortly Mrs. Brown came to the door looking as white as a sheet of paper, while the excited cries from the children met my ears: “Miss Hall, Miss Hall, there is a dead man in the basement! We saw him!!!” I turned to Mrs. Brown, who refused to venture downstairs into the kitchen where the body lay. Visibly shaken, she informed me that she had called the campus maintenance men to investigate. Now I knew her marbles were really being shaken. The campus maintenance men and not the sheriff! I could see her reasoning in keeping the children in the school as their parents were at work. But the campus maintenance men? We could be waiting for hours because they were busy and hadn’t been told the nature of the problem, just “You will see the emergency when you get here.” It had been two hours already. Finally, after much whispered discussion, two of the more daring teenagers in the class stealthily tiptoed down the basement steps, gingerly opened the previously slammed shut door to the kitchen, peered in, and then thundered back upstairs. “Mrs. Brown, Mrs. Brown! There is no dead man. That’s a dummy!” Then I remembered that I had placed a manikin down there several weeks prior to my trip home as I wanted to teach a simple hydrotherapy treatment in my basic health class. Needless to say, it was at least a month before Mrs. Brown fully forgave me. My point is that imaginary stress can produce many of the same effects as real stress. So, one of the cardinal principles of stress management is to distinguish between real and imaginary stress. We don’t have to live in the dread arising from imaginary stress.

Regularity Reduces Stress

It is very important to learn how to manage everyday ongoing stressors by incorporating a regular schedule of healthy meals and exercise with early-to-bed patterns and deep breathing exercises. Regularity helps to maintain cortisol within normal limits and reinforces the natural biorhythms of the body.

How to Achieve a Natural High

Regular physical exercise helps to reduce stress in several ways. For example, exercise reduces sympathetic nervous system tone. Exercise also increases norepinephrine, which is a natural anti-depressant neurotransmitter. Exercise, along with a high complex carbohydrate diet, increases serotonin level – the neurotransmitter that contributes to a positive outlook.

What You Eat Helps to Determine What Eats You!

Proper diet is important in stress control. Wise calorie restriction reduces sympathetic nerve activation and lowers blood pressure in obese individuals prior to weight loss. All nutrients are important in maintaining a healthy brain. Be sure to emphasize colorful fruits and vegetables, whole grains, and an ounce of unsalted nuts in your daily diet. Avoid caffeine because it amplifies the effects of sympathetic nervous system stimulation.

Certain stresses increase inflammation within the body. Clinical, experimental data suggest the importance of inflammation pathways in modulating the rate of age-related tissue damage, organ dysfunction, and longevity in various organs, including the brain. A well-balanced vegetarian diet can help to reduce inflammation within the brain and slow down brain aging (if vitamin B-12 and vitamin D is included). Why is this important? A healthy brain is essential to an alert, responsive, thinking mind.

Enjoy Hydrotherapy

A neutral bath of 97-98° will quiet the nerves.

Another Stress Buster

The last principle of stress management that I would like to leave with you today is to avoid the avoidable stressors. Vicarious stress, as in watching T.V. drama or theater thrillers, activates the sympathetic nervous system. Just as we watch the hero on the brink of near death if the rescuer doesn’t interpose, the heart rate increases, our muscles tighten, and the ability of our blood vessels to dilate becomes compromised. Our time is much better spent in activities that stimulate the brain in a more healthful way—playing classical music, singing, gardening, socializing, and other constructive hobbies.

This article was excerpted from The Lifestyle Physiology Script Book of the College of Health Evangelism, online division and is used with their permission.