The GAS Model
Selye's research led him to conclude that when animals are exposed to unpleasant stimuli, they display a universal response to all stressors. He called this general adaptation syndrome (GAS).
- It is 'General' because it is the same response to all agents.
- The term 'adaptation' is used because it is adaptive - the healthiest way for the body to cope with extreme stress.
- It is a 'syndrome' because there were several symptoms in the stress response.
Selye proposed three stages that lead up to illness, thus linking stress and illness - stress results in a depletion of physiological resources, which lowers the organism's resistance to infection.
Stage 1: Alarm reaction
The threat or stressor is recognised and a response is made to the alarm. The hypothalamus in the brain triggers the production of adrenaline from the adrenal glands. Adrenaline causes sensations that are often labelled an 'adrenaline rush' - increased heart rate, sweaty palms, fast breathing and so on. This leads to readiness for 'fight or flight'.
Stage 2: Resistance
If the stress continues, then it is necessary to find some means of coping. The body is adapting to the demands of the environment, but at the same time resources are gradually being depleted. The body appears to be coping wheras, in reality, physiologically speaking, things are deteriorating.
Stage 3: Exhaustion
Eventually the body's systems can no longer maintain normal functioning. At…