Stages of Fight or Flight

The fight or flight response or nervous system, synonymous with the sympathetic nervous system, is activated in response to actual or perceived physical danger, as discussed in the What Is Stress section. The term fight or flight is slightly deceptive in that one might assume that the potential responses the body is preparing for are fighting and fleeing. This is not untrue, but also does not describe every stage of fight or flight. For example, there are two stages that help the body curl into a ball and decrease internal organ activity in order to aid the playing dead response (as a strategy, for example, in which a predator will only pursue prey they perceive to be alive). When looked at from a psychotherapy perspective, these curl – or collapse – stages are sometimes referred to as the trauma end of the stress-trauma continuum. There are numerous models, in fact, that discuss stages of stress and trauma. The Fajardo Method of Holistic Biomechanics™ works with a seven-stage model, so I will describe that here. Visual illustration is extremely helpful for understanding the changes in body shape I’m about to describe. Stanley Kelleman’s book Emotional Anatomy is a helpful reference for this.

Stage 1: Startle

This is a stage of heightened alertness and investigation. There is the potential for danger, and the nervous system will take in sensory information about the surrounding environment to determine if a fight or flight situation exists and then continue or halt the stress response based on this. This is the stage in which the fewest physiological and anatomical changes occur. Eye sockets narrow slightly – no tunnel vision at this stage – and stress hormones (adrenalin, cortisol, and glucocorticoids) are produced in this stage and throughout all stages of the fight or flight response.

For someone living in a relatively physically safe environment, the startle stage should trigger perhaps several hundred times a day as the body investigates novel sensory information – for example, brighter light as you exit a building, a unexpected shout or other noise, temperature changes, etc. For a well-functioning nervous system, the startle stage would quickly return to the parasympathetic nervous system state upon determination that no immediate physical danger exists.

Stage 2: Fight

The chest cavity enlarges during this stage due to an increase in internal pressure, while pressure in the head and pelvic chambers begins to decrease. The decrease in head and pelvic pressure is a step toward the “curl into a ball” process, which completes itself in the collapse stages. (Internal pressure allows the body to hold its shape against the forces of the external world and to have posture. Ideally the different pressure chambers of the body would be balanced and internal pressure would match pressure being exerted on the body by the external environment. The pressure changes in fight or flight change the shape of the body, as, for example, in creating the curl into a ball shape). Blood flow increases to the muscles in the arms and legs to provide energy for vigorous movement. Water flows out of the arms and legs toward the center of the body.

Stage 3: Flight

In this stage, the body starts to twist and side shift, following the instinct to run away. The twists may not be uniform in direction – for example, shoulders may twist to the right while hips twist to the left. This can cause spinal twists and side shifts as well, sometimes diagnosed as scoliosis.

Stage 4: Freeze

The twists remain as the head and pelvic pressure continues to decrease. The pelvis continues the “curl into a ball” process, and the shoulder girdle (collarbone and shoulder blades) begins this process as well.

Stage 5: Collapse I

Chest cavity decreases, while head and pelvic cavities continue to decrease pressure and curl toward each other. Organ motility decreases as the body begins to shut down internal processes such as digestion.

Stage 6: Collapse II

Changes in the first collapse stage become more extreme. The body cavities have all been decreasing in size; now the organs begin to swell as they fill with water to provide some support and shape that is no longer being provided by normal internal pressure from a functioning valve system.

Stage 7: Rigor

Without sensory input to inform appropriate muscle tension for movement or supporting the body, the muscles increase to their highest tension. Muscles are dehydrated. The high muscular tension and lack of hydration make movement extremely slow and difficult, and sometimes spastic. Often this stage is associated with death, though there are some cases of this occurring during life as an extreme fight or flight response.

Though these stages appear to describe a progression, in fact an individual can be in multiple “stages” at once in different areas of the body, or switch between states in no particular order. The stages are more of a grouping of the structural changes that occur, and a recognition that these changes can be viewed as a continuum. For example, in the set of changes labeled “fight” the pelvic and head chambers start to shrink, and this is much more pronounced in the stages labeled “collapse”. The stage labeled “freeze” would exhibit a pelvis with less pressure than in fight and with more pressure than in collapse.

How To Address Stress

To understand a little more about stress and the advantages of the stress response, see the What Is Stress page. To learn how to effectively address the stress response, see the How To Reduce Stress page.