The Sympathetic nervous system is better known as the “flight or flight” response. It is the branch of the Autonomic Nervous System (ANS) that controls the body’s reaction to physical and emotional stressors.
The Sympathetic system is constantly active, but activity increases in response to stressful stimuli and decreases in response to Parasympathetic activation. When the Sympathetic is activated, adrenaline is released, heart rate increases, blood vessels constrict, sweating occurs, digestion is inhibited, and the pupils dilate.
This response is useful in the short term because it aides the body in responding quickly and effectively to stress. In the long term, however, the Sympathetic response can become harmful. This is because the functions of Sympathetic activation put additional stress on the nervous system. If the Sympathetic system remains highly active, the Parasympathetic response will not activate and return the body to homeostasis. This means the body does not get the chance to recover from stress. Chronic Sympathetic activation can cause Allostatic Load.
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