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What is Fight or Flight?

Back in the 1930’s, Harvard physiologist Walter Cannon was the first to coin
the term ‘fight or flight.’ He used it to describe our innate defense mechanism in the face of a threat or danger. Currently in Kinesiology we also refer to this state as "survival mode".

The classic example of this is primitive man’s physiological response to seeing a sabre tooth tiger nearby. This imminent danger triggers subconscious reflexes that immediately recruit his resources in an attempt to insure his survival. His body prepares to fight to the death or flee for his life.

Adrenaline and other hormones, like cortisol, are released into his bloodstream. The liver releases stored sugar for an immediate energy boost. Blood flow increases to his brain, heart, lungs and large muscles (at the expense of lower priority functions like digestion, etc). His heart beats faster and his blood pressure rises. His breathing becomes more shallow and rapid to obtain more oxygen. Perspiration increases to keep his body cool. His senses become heightened and his pupils dilate to let in more light. His vision tunes out extraneous peripheral information so he can focus on the tiger, or zero in on his escape route. His muscles become tensed, ready to fight or flee.

In the 1950's, Hans Selye wrote a book called "The Stress of LIfe". In it he expanded on Cannons work, finding that our stress response was the same whether we were responding to a sabre tooth tiger, a test with a time limit, a boss in a bad mood or an argument with a spouse. Click here to read about Selye's three-phase general adaptation syndrome designed to protect us.


There are wide-ranging physical, psychological and behavioral symptoms of being stuck in ‘fight or flight.’

Many people clearly see that they are functioning differently after some stressful or traumatic period or event. They know their symptoms arose from their job, divorce, auto accident, troubled relationship, illness, etc.

But most of us have no idea we are functioning in ‘fight or flight,'…

…especially when there is no ‘before and after’ frame of reference. Sometimes symptoms develop so gradually that they are not always associated with the stress or trauma that might have precipitated them.
Or when stress occurs over a long enough period of time (or from an early age), frequently there is no recognition that performance has suffered.

Often there is recognition, but no accurate explanation. Usually we find other things to blame, like age or fatigue. We rationalize we’re just doing the best we can.



"When our nervous system goes into overdrive, the result is overproduction of 'warrior hormones' and underproduction of other hormones...critical to our health and happiness" (Cherewatenko and Perry, 'The Stress Cure').

Early on, symptoms can be very subtle. Many people experience varying degrees of emotional or behavioral difficulties, such as reduced focus and concentration, difficulty handling stress, feelings of frustration, anger, anxiety, depression, fear and overwhelm, just to name a few.

They may have trouble thinking clearly or have difficulty with memory or other cognitive functions. They may tend to be more reactive, overly sensitive or defensive. Performing everyday tasks like driving and reading can become less comfortable or efficient.

Often their perspective becomes narrowed, limiting their ability to see the ‘big picture’ (especially about themselves) …and much, much more.

The physical response can also be very subtle initially, but in the more obvious instances symptoms often mirror chronic versions of the acute reaction to seeing that sabre tooth tiger nearby:

  • Increased heart rate
  • Shallow chest breathing
  • Muscle tension and twitches
  • Fatigue
  • Excessive sweating
  • Cold extremities
  • Headache
  • Digestive problems
  • Reduced immune system
        …and more

As you can imagine, when long-term, these effects can ultimately manifest in any number of physical anomalies.






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