The Chemistry of Fight or Flight


The Fight or Flight Response is a subconscious survival instinct that may just save your life or someone else’s. I chose this “Chemistry of…” because psychology is a topic I am very interested in. The Fight or Flight response may be more automatic than psychological but it lends to your survival and mental health all the same. Fight/Flight is a reaction people experience more often than most think, both in in life or death situations and in situations where the only threat is one that only you perceive. It can help you to continue to live, either by getting your out of a situation or someone else reacting in time to save you, or it can cripple and halt a life all together when out of control. A regular catch twenty-two.

  • Composition of ...
    • brain:
      • hypothalamus
      • cerebral cortex
      • amygdala
    • catecholamines
      • norepinephrine/noradrenaline (C8H11NO3)
      • epinephrine/adrenaline (C9H13NO3)
    • hormones
        • hypothalamic pituitary adrenal system
      • estrogen (C18H24O2)
      • testosterone (C19H28O2)
      • cortisol (C21H30O5)
    • neurotransmitters
      • dopamine (C8H11NO2)
      • serotonin (C10H12N2O)
    • autonomic nervous system
      • sympathetic nervous system
    • muscles
    • eyes
    • respiratory system
    • cardiovascular system

Main Chemicals, Compounds, Components

The two most important parts in you Fight or Flight response are: the Autonomic Nervous System and catecholamines. The ANS is the system that oversees all the body functions that don’t require specific thought as moving an arm does, for example breathing, heartbeat, and your digestive system. . The Fight or Flight response is similarly activate as an automatic response. No one chooses to activate their Fight or Flight response it happens completely independently of your conscious thought. The ANS takes over and activates this response when you perceive a threat and spreads the message all over your body to get ready to survive whatever it takes. Where the Autonomic Nervous System is the control center, catecholamines (neurotransmitters) are the heavy lifters. Specifically epinephrine and norepinephrine. These transmitters are released from your adrenal glands and actually prime the body for fight or flight. Norepinephrine increases vigilance and readys your body while epinephrine makes to body faster and stronger to act.

Chemistry's Role

Norepinephrine is an organic chemical that is synthesized in the brain and adrenal medulla.

When released in brain it affects where attention and responding actions are controlled. It increases alertness, enhances formation and retrieval of memories, and focuses attention. In the body norepinephrine affects each tissue respectively by targeting cells and binding to and activating adrenergic receptors. Each cell is then prompted the either shut down, slow down, restrict, or speed up according it their function in your survival. Every cell and tissue is affected differently to mobilize your brain and body for action. Epinephrine is released directly into the bloodstream from the adrenal glands in your kidneys and is carried to various locations where it binds to the alpha-adrenergic receptors, specifically alpha-2-adrenergic receptors to initiate different responses as with norepinephrine. The purpose of this is to provide energy to the major muscle groups so that the body can respond to the threat.

Background Research

The Fight or Flight response is a hyper arousal, acute stress response in the Sympathetic Nervous System (SNS), part of the Autonomic Nervous system(ANS), in reaction to a perceived harmful event or threat --whether physical or psychological. The theory was first presented by Walter Bradford Cannon, who recognized that there was a general discharge in the SNS to ready an animal to fight or run away from a threat. The process begins with the recognition of a possible threat which triggers the adrenal medulla to release norepinephrine, epinephrine, and other hormones (estrogen, testosterone, and cortisol) into the body. These stress hormones put the body on alert, increase heartrate and breathing, stimulates metabolism, and deverts oxygen and blood to the major muscle groups. This all happens automatically without any conscious thought from you. This response preps your body to either deal with or run away from the threat and to quickly and intuitively decide between the two. This quick action plays a key role in survival, with this response in action, you are more likely to cope effectively and perform in a situation when you otherwise wouldn’t.

The fight or flight response also plays a large role in Post-Traumatic Stress Disorder. Where normally a fight/flight response is healthy and normal, in PTSD the reaction is changed or damaged. A person can continue to feel stressed or frightened even when there is no danger present or a response can be triggered that is out of proportion to the perceived threat. PTSD is like being stuck constantly in a fight or flight situation, whether there is a threat or not. Also, not all people with PTSD are survivors of physical trauma. Any situation where a person feels a threat to their own well being, physically or mentally, or that of someone else can trigger a fight/flight response, the same can be said of PTSD.

But a fight/flight response isn’t just relevant to soldiers in PTSD. Part of military or law enforcement training is learning to train your Fight or Flight response to automatically set to fight. A soldier or cop who runs from danger or freezes up in the face of it is not very useful. To prevent this, soldiers and law enforcement are often trained out of their fear/flight responses. They use their fight response to better their performance and increase their chance of survival in high stress and very dangerous situations.


About the Author

Kinley Apuna is a student at Billings Senior High. She’s born and raised in Montana (even though she was born in the absolute wrong state) but likes getting out into the world. Eventually, come Hell or high water --or ISIS-- she is going to spend a summer traveling around Europe. As for college, she’s not sure where she wants to go or what she wants to do. Her two loves are building things and questioning why people do things, so it’s either some field of mechanical engineering or some field of psychology. Until then, she is in STEM Society and plans to compete in Montana’s TSA engineering competition.