Hans Selye - Three-Stage Response
In the 1930's, Hans Selye was researching the effects of hormones when he noticed that rats would become ill even when they were given harmless injections.
He concluded that the stress of the daily injections caused the ilness and suggested humans and animals react to stressors through a three stage physiological response. General Adaptation Syndrome (GAS)
- Alarm - when a stressor is percieved, the body's first reaction is to increase arousal levels so we are ready for any needed physical response.
- Resistance - if the stressor remains for a long time, our bodies can adapt to the situation and we seem to be able to cope in a normal way.
- Exhaustion - after long-term exposure to a stressor our bodies will eventually be unable to continue to cope with the situation. Alarm signs may return and we may develop illnesses (diseases of adaptation)
Evaluation - the stages are supported by scientific research. However, theory describes a single response when it can differ dependent on the stressor.
Long term stress can affect the cardiovascular system
Krantz et al - Stress and the heart
Method: In a lab experiment, 39 participants did one of three stress inducing tasks (maths, stroop and public speaking). Their blood pressure and the extent to which the vessels around their heart contracted was measured. They were instructed not to take any heart medication prior.
Results: Participants with the greater myocardial ischaemia showed the highest increases in blood pressure. A small number…