Fight or Flight Response

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Definition

The fight or flight response is a catch-all phrase describing the body's response to stress. Fight or flight refers to the two choices our ancestors had when facing a dangerous animal or enemy. In that moment of stress (fear) the body prepares itself to be injured and to expend energy in the large muscle groups of the arms, legs, and shoulders that we use to either fight or run (flight).

Physical Symptoms

A fight or flight response causes a few common signs:

  • Cool, pale skin: Blood flow to the surface of the body is reduced so that the blood flow to the arms, legs, shoulders, brain, eyes, ears and nose can be increased. Besides getting ready to run and fight, the body is preparing to think quickly and be aware of threats by hearing, seeing and smelling things better. Pulling blood away from the skin also helps decrease bleeding from cuts and scrapes.
  • Sweating: Running or wrestling with bears will certainly cause an increase in body heat. To prepare for that, the body starts to sweat as soon as it feels stressed. So not only is our sense of smell heightened but so is how we smell to others (body odor). In medical terms, this kind of sweating is also known as diaphoresis.
  • Dilated pupils: To let more light in and improve sight, the pupils dilate.
  • Dry mouth: Gastric juices and saliva production decrease because blood flow to the digestive system is decreased. The body can interrupt digestion of that cheeseburger until after the threat has been eliminated. Think of it as a priority system: It's more important to live now than to digest food. This same reaction can also cause an upset stomach.

    Bottom Line

    The fight or flight response is a direct result of adrenaline being released into the bloodstream. Anything that causes stress to the body will trigger a fight or flight response -- angry boss, deadlines, family fight, illness, car accident, heart attack, etc.

    Also Known As: fight or flight syndrome, stress response, adrenaline rush, adrenergic response, catecholamine response

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