The Fight or Flight Response

What is the fight or flight response?

Any perceived possible threat to our survival, whether real or unreal sends information to the most primitive, reactive part of our brain which creates unavoidably noticeable signals to instinctively protect ourselves. This is known as ‘The Fight or Flight’ mechanism.

Albeit a very normal physiological response to a danger or threat, the Fight or Flight mechanism is a survival instinct that our ancient ancestors developed many years ago, enabling us to run away (take flight), fight, or freeze to be less visible when faced with danger. This response kept us alive because we needed to be on full alert from attacks by wild animals, warriors etc.

As the Fight or Flight mechanism is activated, a combination of nerve and hormonal signals prompts our adrenal glands, (located at the top of the kidneys), to release hormones, including adrenaline and cortisol.

Adrenaline increases your heart rate, blood pressure and energy supplies, whilst cortisol, which is our primary stress hormone, increases sugars (glucose) in the bloodstream. This enhances your brain’s use of glucose and slows down anything that is detrimental to the efficiency of your fight or flight system.

The Fight or Flight response was designed to deal with actual fear for our lives, but in today’s evolved world, is now predominantly triggered by feelings of, but not physical threats. However, as we continually engage our Fight or Flight response, we experience physical symptoms designed to temporarily change the way the body is functioning in order to enable rapid physical response. 


  • Heart beats faster
  • Circulation increases blood supply to our brain and muscles.
  • Blood pressure and body temperature rises.
  • We increase oxygen levels by breathing more (leading often to hyperventilating)
  • Pupils dilate so we have a greater awareness and vision.
  • Brain activity alters to think less but react more.
  • Arteries dilate.
  • Digestion slows down
  • The dump mechanism is instigated to make us lighter (this can include the need to use the toilet or vomit).

Understanding why the physical symptoms (above) kick in as they do will reassure you that your body is trying to protect you and not work against you.

Read more: Ways to reduce panic attacks


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