“What is fear anyway? It’s a series of automatic responses to a given stimulus, characterized by increased heart rate, respiratory activity, and adrenaline function. The only problem with fear is that it has largely become inappropriate and non-adaptive. Do sweaty palms help to talk to your boss? Does a racing pulse help some kid score in an SAT? Yet we carry with us these primordial fear responses that do the opposite of what they were intended to do. So why is that?” [i]


This quote makes an interesting point. Fear is often inconvenient, and at times completely inappropriate. So that begs the question: why do we have this fear response? To answer that, we have to look at the nervous system, and more specifically the Sympathetic Nervous System.

The Sympathetic Nervous System controls our fight, flight or freeze response. It is our body’s emergency response system. It served an important function thousands of years ago because the main dangers we experienced were physical and immediate. It is an evolutionary throwback to when the fight/flight/freeze response meant life or death in dangerous situations. When a danger or threat is present, our bodies respond with a surge of adrenaline. In response to the adrenaline, heart rate increases, breathing becomes short and fast, blood flow is diverted from nonessential areas, the digestive system is shut down or ‘vacated’ if necessary (hence either nausea or a need to go to the bathroom are common), perspiration is increased, and the immune system is suppressed. All of these changes are directly linked to a physiological preparation for action, for fight or flight. Those with the quickest and most extreme sympathetic response were the most likely to survive, reproduce, and pass on the trait to their descendants. This is the very essence of survival of the fittest. [ii]

A problem with this system is that the situations that typically cause stress and danger changed over time as humanity became civilized. We do not often find ourselves facing wild animals. Most people no longer compete violently for limited resources… well not as much anyway. Our lives are not put at risk as often. Because of the functions of the sympathetic system, it is a natural response to want to fight, flee or freeze up. These are useful responses in the wild, but not in the civilized world.

The same physiological reactions that were once desirable and increased the likelihood of survival now may be socially inconvenient and embarrassing. However, while they may be highly inconvenient, they are not life threatening. As a result, the same process of evolution that once cultivated these responses will not correct them. People who have high fear responses aren’t less likely to survive, just less likely to succeed in certain social scenarios, such as socializing at parties or public speaking.

Also, because the fear response system evolved to resolve, defeat, or escape threats, it tends to function until a threat is removed. The social and psychological threats we face today don’t usually resolve quickly, they tend to go on for some time, sometimes years. This can mean people continuing to function with their sympathetic systems perpetually engaged over a longer period than it ought to be. The sympathetic stress response is highly functional in an emergency, but detrimental if engaged over the long term. Imagine a military on high or red alert indefinitely. Everyone is at battle stations, ready for an attack. How do you think those soldiers would be functioning after a while? Certainly not at their best. Everyone needs down time. Systems work best when emergencies are frequent enough to keep the system alert, but short lived enough so that the system can recover.

Many health problems can be linked to a sympathetic response that is repeatedly or perpetually engaged over time. The sympathetic nervous system activates two hormones, Adrenaline and Cortisol. These serve various functions, including a quick burst of energy, increased memory function, improved immunity, lower pain sensitivity, releasing blood sugar from the liver and amino acids from muscles, all of which provide the energy for fight or flight.

These are useful functions during an emergency, but damaging if continually activated over a long term. While Adrenaline leaves your system as soon as you recognize that the danger is over, Cortisol does not. If the threat does not require you to use the persistently increased blood sugar and amino acids in fight or flight, then you may develop hyperglycemia and the blood sugar will be deposited as fat (especially around the belly), which increases the risk of diabetes, stroke, and cholesterol-related problems. Higher and more prolonged levels of Cortisol also lead to impaired cognitive performance, decreased bone density and muscle tissue, a reduced immune response, and overextending the inflammatory response. Over time, prolonged inflammation increases the risk of heart disease and cancer, and accelerates the aging process. The costs of a sympathetic response in a civilized world go beyond social embarrassment; long-term stress is hazardous to one’s health. [iii]

So, the fight/flight/freeze responses remain part of our genetic makeup, like them or not. They may be inconvenient, or even potentially damaging to one’s health, but they have not completely lost their usefulness. While the situations that truly require a sympathetic response to survive are less frequent in a civilized world, they are not unheard of just yet. If an 18-wheeler was barreling towards you, if a mugger attacked you, or if a dog were chasing you, you would want those primordial fear responses just the way they are.

The real problem is that, on a physiological level, there is no distinction between psychological anxiety and physical fear. Our bodies can’t tell the difference between different kinds or sources of fear, so we have the same physiological response before a big meeting as we do to an attacking bear. And since this lack of distinction is not a matter of survival, we are unlikely to develop such a distinction. This lesson also applies to several other emotional/physiological reactions that are inconvenient or undesired, such as anger.


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“Courage is not the absence of despair; it is, rather, the capacity to move ahead in spite of despair.”         -Rollo May


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“Fear is the mind killer. Fear is the little death that brings total obliteration. I will face my fear. I will permit it to pass over me and through me. And when it has gone past, I will turn the inner eye to see its path. Where the fear has gone, there will be nothing. Only I will remain.” [iv]


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“Don’t worry that such and such will happen. Don’t create such anxieties. Rather, wait and see what happens, wait and see what events occur in your life. Feel anguished or elated if such feelings are part of the experience. That’s part of being human. But don’t categorize life experiences as negative or positive, miserable or happy. Then whatever happens let it happen… and learn from it.”                   – Sensei Ogui


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“ Don’t worry about the future. Or worry, but know that worrying is as effective as trying to solve an algebra equation by chewing bubble gum. The real troubles in your life are apt to be things that never crossed your worried mind, the kind that blindside you at 4 pm on some idle Tuesday.”

–      Mary Schmich [v]



[i] Quoted from the movie The Haunting (of House Hill) (1999). The character Dr. David Marrow, played by Liam Neeson, is studying fear.


[ii] Chudler,Eric H. (1996-2007). The Autonomic Nervous System. Neuroscience for kids. Retrieved August 2, 2007, from http://faculty.washington.edu/chudler/auto.html

Bakewell, S. (1995). The Autonomic Nervous System. Update in Anaesthesia 5. Article 6. http://www.nda.ox.ac.uk/wfsa/html/u05/u05_010.htm


[iii] Boudreau, Diane (2002). Unraveling the Stress Within. Retrieved August 2, 2007, fromArizona State University, ASU Research Web site: http://researchmag.asu.edu/stories/stress.html

Bruce, D.G.; Chisholm, D. J.; Storlien, L. H.;  Kraegen,, E. W.; and Smythe, G. A. (1992, September). The effects of sympathetic nervous system activation and psychological stress on glucose metabolism and blood pressure in subjects with Type 2 (non-insulin-dependent) diabetes mellitus [Electronic version]. Diabetologia 35I(9), 835-843.

Scott, Elizabeth. (2007, November 7). Cortisol and Stress: How to Stay Healthy. Retrieved December 13, 2007 from About.com Web site: http://stress.about.com/od/stresshealth/a/cortisol.htm

    Nervous System (n.d.) Retrieved August 2, 2007, from http://stresshelp.tripod.com/id15.html


[iv] Frank Herbert, Dune (New York: Berkley Books, 1965), 8.


[v] Originally part of the article Advice, like youth, probably just wasted on the young published in the Chicago Tribune June 1, 1997. This essay was set to music and released by Baz Luhrmann in the song Wear Sunscreen (1999). Mary Schmich eventually published the essay as the book Wear Sunscreen (Kansas City, MO: Andrews McMeel Publishing, 1998)


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