General adaptation syndrome describes the body’s short-term and long-term reaction to stress. Originally described by Hans De Solye in the 1920s, the general adaptation syndrome describes a three stage reaction to stress covering our initial reaction to the stressor, our resistance and adaptation to coping with the stressor and our eventual exhaustion after dealing with the stress whereby in normal circumstances we will recover from that exhaustion and live to deal with stressors another day.

Alarm Reaction Phase

During the alarm reaction phase, a stressor disturbs homeostasis. Homeostasis is a point of balance or internal biological equilibrium. The brain subconsciously perceives the stressor and prepares the body either to fight or to run away, a response sometimes called the fight or flight response. When the mind perceives a stressor, the cerebral cortex, is called to attention. If the cerebral cortex consciously or unconsciously perceives a threat, it triggers an autonomic nervous system response that prepares the body for action.

The autonomic nervous system is the portion of the central nervous system that regulates bodily functions that we do not normally consciously control. When we are stressed, the rate of all these bodily functions increases dramatically to give us the physical strength to protect ourselves against an attack, or to mobilize internal forces.

In addition to this, the hypothalamus, a section of the brain, functions as the control centre and determines the overall reaction to stressors. When the hypothalamus perceives that extra energy is needed to fight a stressor, it stimulates the adrenal glands to release the hormone epinephrine, also called adrenaline. Epinephrine causes more blood to be pumped with each beat of the heart, dilates the air sacs in the lungs to increase oxygen intake, increases the breathing rate, stimulates the liver to release more glucose, and dilates the pupils to improve visual sensitivity.

The body is then poised to act immediately. Other physical responses to stress during this stage include “butterflies” in the stomach, an elevation in blood pressure, dry mouth and tensing of muscles. In some instances if too intense or if for too long the individual may find it difficult to concentrate on preparing well to deal with the stress properly.

The alarm reaction directs resources away from the digestive and immune systems to more immediate muscular and emotional needs. In normal circumstances the alarm reaction phase will not last for very long, in some instances it may only be for a few seconds, in other instances longer. The alarm reaction phase is only meant to be a preliminary phase of activating the body and mind into dealing effectively with the presenting stressor or threat.

Resistance (adaptation) Phase

As we move from the initial alarm reaction phase, as a preparatory response to the presenting stressor, we then move onto the resistance or adaptation phase. It is in this phase where the body is now actively dealing with the stressor. If this adaptation phase continues for a prolonged period of time without periods of relaxation and rest to counterbalance the stress response and allow time for the body to replenish and repair from the exertion required to execute the appropriate stress response, sufferers become prone to fatigue, concentration lapses, irritability and lethargy as the effort to sustain arousal slides into negative stress.

At the most fundamental level of response the organism is going to be either fighting or fleeing in some way, in an attempt to resist the negatively perceived consequences of the threatening stressor. This resistance may be required for either, a few moments, days, months and sometimes even years. The form of resistance employed will have varying degrees of success depending on how well it is employed and how relevant it is in dealing with the stressor situation. Regardless of the length of time, once the threatening stressor has been dealt with effectively the organism is able to return to its pre-activated state and recover from the ordeal. It is in the process of recovery that adaptation occurs.

Every organism has restricted resources to adapt to stressors. Therefore, whenever someone has to adapt to a stressor they will loose “adaptation energy” meaning that they will have less resources to adapt next time they are confronted with a stressor unless they adapt successfully.

Successful adaptation from resistance is when the body and mind adapts to a point of being more capable in its capacity to resist if ever confronted by the stressor again. In this sense, successful adaptation means the organism has increased its biopsychosocial level of fitness whereby it can take on the same threat more effectively next time or successfully take on a bigger threat next time.

It is through this process of adaptation that we learn how to cope better and deal with things more effectively. At a physiological level successful adaptation actually means getting physically fitter. Psychosocially it means having greater levels of resilience, working better coping strategies and having more appropriate emotions and thought processes around the challenging situation.

Problems occur at the resistance/adaptation phase if the combined biological, psychological and social responses employed do not deal with the threat effectively or if the threat is chronic whereby it eventually wears down the capacity of the organism to resist the threat or deal with it properly. This problem leads us to the exhaustion phase of the general adaptation syndrome.

Exhaustion Phase

A person can only fight or flee for so long before they begin to wear down in their capacity to resist and deal with it. If the stressor environment is chronic and excessive without any real opportunity to recover or adapt successfully, the organism will begin to show signs of adaptation failure. Systems begin to break down and we become more susceptible to a range of biopsychosocial symptoms. If we persist in functioning at this level, death can occur.