The Physiology of Fear and Anxiety

vitruvian man

Let’s take a brief look at the physiology of fear and anxiety. Imagine that you have travelled back millions of years in time. You are sitting beside a camp fire in a cave enjoying your meal. Your body’s muscles are relaxed and you feel happy.

Suddenly, in your peripheral vision you notice an animal nearby. As soon as you turn your head, a large and ferocious-looking sabre toothed tiger charges toward you!

Immediately your body goes through a series of drastic changes caused by the “fight or flight” response – Mother Nature’s way of protecting you from danger.

This innate and automatic response to fear and anxiety is characterized by a chain reaction originating from the brain which orders the secretion of adrenaline. This hormone brings about the following changes in your body:

  1. The pupils of your eyes dilate to allow more light in, and also to sharpen your vision for the obvious reason that in times of perceived danger you need to see as much as you can.
  2. Your mouth goes dry to avoid adding fluids to your stomach.
  3. Your digestion also stops temporarily, allowing more blood to be directed to the muscles and brain. This explains why under the effects of fear and anxiety you feel “butterflies” in your stomach.
  4. Your neck and shoulders tense up in order to prepare for action. Tense muscles are more resilient to blows than relaxed ones.
  5. Your breathing quickens to allow an increased flow of oxygen to your muscles.
  6. Your heart beats faster and your blood pressure rises, thereby providing more fuel and oxygen to various parts of your body.
  7. You begin to sweat more in order to cool your body (from an expected increase in exertion). The more energy the body burns, the more you perspire.
  8. Your liver releases glucose to provide a quick source of energy for your muscles.
  9. Your spleen releases its stored blood cells and chemicals into the blood stream to thicken the blood. This process allows the blood to clot more rapidly than usual, so that if injury should occur, bleeding will stop more quickly. Moreover, the body becomes more resistant to infection.

This reaction, then, is your body’s preparation for either confronting or fleeing from danger. No matter whether your split-second decision is to fight or to run away, your body will need all the alertness and extra energy it can get.

These automatic responses to danger are still with us as reflexes. Some specific situations, objects or events can trigger the brain to initiate all the above physiological events. Alarmingly, the same reactions are elicited whether the danger is real, rational or imaginary and totally irrational.

However, unlike the cave dwellers who either fought or ran, we are often trapped within our anxiety and fear predicament without a direct means of addressing them.

We are all, and must be, anxious at certain times. This is a necessary and inevitable mechanism to mobilize our resources. However, the key difference between healthy levels of anxiety and a pathological one is one of degrees. If your anxiety level is so high and so frequent that limits your life, then this is a problem.

For example, we all must take care of our hygiene and wash our hands several times a day. Our motivation is both the good feeling that we get when we have clean hands, and also our fear of bacteria and germs. The problem occurs when your fear of disease turns excessive. I recall a young man in Sweden who washed his hands with ferocity and vengeance multiple times a day. Every time he went to the bathroom or touch meat in the kitchen, he washed his hands repeatedly. Throughout the day he was constantly inspecting his hands to see if they were clean. Any discolouration or slight change in the colour of his hand pushed him to wash his hands over and over. Not surprisingly, his skin was extremely dry.

Equally, anxiety becomes problematic when we feel unable to live a normal life and limit our social interactions with others.

Even though the reaction of anxiety and fear is an innate and natural response, we all have different thresholds. Some people are more resilient than others. There are those who get more motivated when they feel fear and anxiety. In extreme cases there are those so called “thrill-seekers” who enjoy risk and dangerous activities like bungee jumping because of the adrenaline rush.