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Fight or Flight Response

By Lisa Fritscher, About.com

Updated: August 29, 2008

About.com Health's Disease and Condition content is reviewed by the Medical Review Board

Definition:

The fight or flight response refers to a specific biochemical reaction that both humans and animals experience during intense stress or fear. The sympathetic nervous system releases hormones that cause changes to occur throughout the body. These changes include, but are not limited to:

  • Increased heart and breathing rate
  • Suppression of the digestive system
  • Release of epinephrine
  • Inhibition of pain

The fight or flight response prepares the body for fast-paced action. Whether you choose to flee or fight, your body will need all of its resources. This is believed to be an evolutionary development and can only be suppressed through intense work and training.

If you have a phobia, the fight or flight response may be activated whenever you are confronted with the object of your fear. This is why you may shake, cry, become hostile or even run from the situation.

A phobia can have a long-term effect on your physical health. Frequent or chronic activation of the fight or flight response, particularly in situations in which neither outcome is practical, can lead to digestive problems, increased risk of heart disease and the other known effects of chronic stress. With treatment, however, you can learn to overcome your fear.

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