Stress and Anxiety Reaction Page #2

Stress and anxiety and the autonomic nervous system

When our brain interprets a situation as dangerous it excites a special group of fibers (nervous system fibers) that quicken our heartbeat and produce other changes that we experience as fear or anxiety. This system of nerve fibers is referred to as the sympathetic nervous system. The sympathetic nervous system is the system that reacts with the "fight or flight" response, the reaction that seems to prepare us for some form of action in response to danger. Fortunately, this stress and anxiety response does not last forever. After the perceived threat has passed, a second group of autonomic nervous system nerve fibers, the parasympathetic nervous system, then returns our body processes back to normal. Together, these two parts of the autonomic nervous system help control our stress and anxiety reactions. They enable our body to function reliably across many different circumstances or situations.

The autonomic nervous system may stimulate organs directly. Or, you may also affect them indirectly through stimulating endocrine glands throughout your body. These glands release hormones into the bloodstream which then cause various bodily reactions. For example, when we are confronted by stressors, the autonomic nervous system triggers the adrenal glands which are located on top of the kidneys, to release a group of hormones called corticosteroids, including the hormone cortisol. These corticosteroids then in turn stimulate various body organs and certain parts of the brain, setting in motion various stress and anxiety reactions. Eventually, these same corticosteroids stimulate the hippocampus of the brain (the part of the brain that seems to regulate emotional memories) and the hippocampus then begins to turn off your body's stress and anxiety reaction.

We all have unique patterns of autonomic nervous system and endocrine functioning, which has a lot to do with how we experience fear, stress and anxiety. One person may react merely with a sense of dread, while another may breath faster and have difficulty concentrating, and perspire profusely. Also, we all have our ongoing unique level of anxiety. Some people are always relaxed while others seem to be tense most of the time. An individual's general level of anxiety is referred to as trait anxiety because it seems to be a ongoing characteristic unique to that individual. Psychologists have found that some differences in trait anxiety may appear soon after birth.

People also seem to differ greatly in their reaction to which situations seem threatening, resulting in their sense of stress and anxiety. Walking through a forest may appear fearful to some or relaxing to another. Flying in airplanes also brings various stress and anxiety reactions to some individuals, while for others merely a sense of boredom. These variations in circumstances that may or may not cause anxiety, are referred to as situation or a state anxiety. In most cases, however, these individual expressions of stress and anxiety are quite different from the waves of tension and dread felt by those individuals who suffer from an actual anxiety disorder.

Some information from DSM-IV-TR Mental Disorders Diagnosis, Etiology & Treatment By Michael B. First and Allan Tasman