What is a Fight or Flight Reaction?

A fight or flight reaction is a response to stress characterized by boosts of adrenaline, dilated pupils and a fast heartbeat. The term was first used in the early 20th century by Walter Cannon, an American physiologist. Cannon used the term to describe animals that underwent situations where they either had to flee or prepare to fight in order to defend themselves from danger. Such a response can also be called hyperarousal, or a response to acute stress. According to Cannon’s descriptions, when an animal is frightened or imperiled, the sympathetic nervous system responds, causing adrenaline boosts and changes in pupils and heartbeat, and sometimes extra strength shown in bursts of speed if an animal runs away or stays to attack. Some also refer to a third state “fright,” occurs when an animal doesn’t flee or fight, but panics and passes out or stands still — the typical “deer in the headlights” response or the collapse of sheep if chased by a dog.

Fight or flight reaction has also been found to occur in humans during times of stress or danger. In some cases, the sympathetic nervous system causes such extreme boosts of adrenaline that people are able to do things they couldn’t under ordinary circumstances, like lift a car off an injured loved one. The fight or flight response can be extremely powerful, but it doesn’t always work to our advantage.

People may encounter this reaction not just in situations of perceived physical danger. They may also feel imperiled during a vocal argument. This can cause them to continue arguing, and some people may even combine physical attack if their sympathetic nervous system works overtime during any type of verbal attack. Others need to flee, and if a person really wants to get out of a verbal argument, you shouldn’t try to stop him or her, since flight can be provoked into fight, if a person can’t get away from the attack and feels cornered.

Moreover, some people, especially those with post traumatic stress disorder (PTSD), panic disorder or generalized anxiety disorder, may have a fight or flight reaction for no apparent or obvious reason. The sympathetic nervous system essentially misfires, and suddenly being unable to find your keys, or something else mundane, causes a rapidly beating heart, heavy breathing, or an outright panic attack. For people with PTSD, small reminders of past traumatic events, like a smell, the temperature or being in a place familiar to where traumatic events occurred can provoke this response. For some, this can provoke aggressive behavior toward others, and yet others find themselves panicking or needing to change environments quickly.

Sometimes the flight response is not particularly overt in humans. Withdrawing from social interaction, even by watching television or surfing the net, could be viewed as a slight flight reaction when times get stressful. In studies on gender and fight or flight reaction it has been observed that men tend to become more aggressive or more withdrawn than do women under stressful situations, probably because in our culture, women tend to be more likely to lean on social resources (friends and family) to discuss their problems.

In all, most people will encounter fight or flight reaction in times of stress. Though it may have once been an instinctual behavior to protect people from danger, just as it now protects many animals, it is sometimes a hassle to deal with. Being in a full hyperarousal state can lead to bowel problems, panic, argumentative mood, withdrawal, and difficulty sleeping and breathing. If this response seems to occur frequently without stimuli, like a real danger or stressful situation unfolding, it may be wise to evaluate ways to address this response with a mental health professional or with your personal physician.