Understanding the Fight and Flight Trauma Responses

Date: 7/6/2026 | By: Dr. Dana Harron

Shared Physiology of the Fight and Flight Trauma Responses

Fight and flight are very similar biological pathways, which is why they are often discussed together.  However, they do have some differences, which we’ll discuss shortly.

Fight and flight are both largely about sending tons of energy to the major muscles as quickly as possible, so that they can be used to battle or to run away.  To this end, breathing becomes really shallow and fast.  The heart starts beating quickly to send all that oxygenated blood to major muscle groups.  Blood flow moves towards those muscle groups too - and away from hands and feet, which is why anxiety can often cause clammy hands.  This also means that if a predator clips you on one of these areas, you’ll lose less blood.  

Pupils dilate so that you can more easily attend to things in the periphery - hello, unanticipated 2nd raptor from Jurassic Park.  Pain sensitivity decreases.  You sweat, which both cools you off and makes you more slippery.  The body halts all non-immediate projects like fighting off colds, repairing cells, and digesting food.  In fact, many people who enter extreme fight/flight may find their bowels or bladder emptied.  This theoretically makes you lighter and increases your agility and speed.

At the same time, the blood flow in your brain literally flows away from the pre-frontal cortex, the part of our brains that does reasoning.  This is why people can get so illogical when they are in one of these states, saying and doing things that they don’t really mean or engaging in behaviors that are ultimately really unhelpful.  They literally cannot think clearly.

Fight Trauma Response

Fight response feels angrier than flight.  The primary hormones involved are testosterone and adrenaline.  Energy is more likely to be sent to the upper body major muscles, since those are more used for attack than for fleeing.  Blood flows more to your face and neck, which is a sort of warning signal to the predator that you mean business.  

This can make you feel hot, and that sensation is related to terms like “hot-headed” and “hot under the collar”.  The jaw clenches because, once upon a time, you might have needed to bite to survive in a situation like this.  Thoughts can feel hyper-focused; it can be difficult to let a perceived injustice go and move on.  Your voice typically gets louder.  Chronic fight activation can present as irritability, demandingness, over-control, and ruminating over perceived slights

Chronic Fight Trauma Response Activation

The trauma responses aren’t all or nothing.  Many people suffer from a constant, low-level activation of the fight response.  This can often feel more like irritability than anger or rage; just a predisposition to not like what’s going on and a sensitivity to the environment around you.

Flight Trauma Response

The primary stress hormones involved are adrenaline and cortisol.  Energy is sent more to the lower muscle groups that would be involved in running away than the arms.  The voice is typically higher-pitched and more breathy.  Thoughts are often panicky and in many directions at once, with a sort of a frenetic quality.  Sometimes people enter into a flurry of ‘productivity’ when they are feeling flight energy, which seems counterintuitive until you realize the busyness is designed to help a person ‘flee’ or avoid an internal experience.  Chronic flight activation can present as compulsive productivity, over-thinking, constant fidgeting, or a tendency to be physically or emotionally absent in certain situation

Chronic Flight Trauma Response

People who have the flight trauma response regularly tend to be chronically busy.  They pile their schedules with too much stuff and keep themselves distracted by trying to meet a million demands at once.  It can often seem like they are stressed about doing so much, but the reality is that they are anxious about what it would mean to slow down.

Reach out to Monarch Wellness & Psychotherapy and start your journey toward safety, stillness, and lasting peace.