The flight-fight response is a complex automatic mechanism that happens in the human or animal body when threatened or confronted by an adversary or harmful situation. It can happen without any conscious thought, but is tied to the psychological makeup of humans and related to stress.
Walter Cannon as a physiologist observed and monitored this type of response first in animals and called it the flight-fight response. It was then also observed in human beings. This is an automatic response where a person's physical being will prepare to either attack or fight; or flee as in flight.
The autonomic system
The flight-fight response is controlled by the autonomic system which is engineered by the central nervous system. The autonomic system is in charge of many physiological responses connected to emotions. The autonomic nervous system controls the automatic, involuntary functions that people experience while living their daily lives. People do not normally think of these involuntary functions.
The sympathetic division
The autonomic nervous system is controlled by two divisions: The sympathetic division and the parasympathetic division. It is the sympathetic division of the autonomic nervous system that directly controls flight-fight responses. In stressful situations or emergencies the sympathetic division of the autonomic nervous system mobilizes the physical body for action. The flight-fight response is also directly connected to survival.
Physical observations present during a sympathetic mobilization are dilated pupils, inhibited salivation, increased respiration, dilated bronchial passages, increased heart rate, inhibited digestion, secretion of adrenal hormones, increased secretion of sweat glands, raised hair follicles, goose bumps, and a relaxed bladder.
Stress and anxiety
Any or all of the above physical observations can be present during a sympathetic mobilization. Therefore, if the body is not able to flee or fight to handle the threat, stress can worsen and cause disease in the body or mind, such as cancer or neurosis. An extreme amount of anxiety can build up whereby it might be impossible for the human to cope, if they do not receive some type of help from outside sources, such as the family doctor, a counselor, a minister or rabbi, or the psychologist or psychiatrist.
How it works
The nerves of the autonomic nervous system are connected to the heart, blood vessels, smooth muscles, and the glands. Signals are sent to the adrenal glands, which set off the release of hormones that cause the body to be ready for action.
There is a direct connection of the nervous system to the endocrine system. The endocrine system is in charge of the glands that control body function. During a flight-fight response the glands secrete chemicals that move throughout the bloodstream to help in the call to action - the flight or the fight.
During a stressful situation the hypothalamus in the brain sends signals to both the autonomous nervous system and the pituitary gland. The response is the adrenal glands sending hormones throughout the body to prepare for the emergency.
This normal and automatic function of the human body or the animal body can be manifested in cases of dire emergency where a person saves another human being such as in war, or fire where the soldier or the fireman save lives. But it can also create anxiety when the person is unable to save oneself in perhaps a domestic violence situation. There may also be a great amount of stress related to the flight-fight response with stress having its own set of of body functions that might go awry. There are ways to control anxiety and stress in these types of situations.
All people experience the flight-fight response. It is a normal and automatic function of the body to help in cases of conditions whereby an emergency is perceived. The flight-fight response can be useful or detrimental depending on your perceptions and your ability to use the flight-fight response effectively.
If you are experiencing extreme anxiety or stress it can be useful to see a professional to help with finding ways to cope with your situation.
Weiten, Wayne, Psychology, sixth edition, Wadsworth, US, 2005.