Selye's General Adaptation Syndrome (GAS)
Works Cited Missing
Hans Selye conducted some research into stress from the 1930's until
he died in 1982.
He thought that short term stress (acute stress) can be adapted by the
body because of the 'flight or fight' response which enables us to
cope with the demands of the environment. Furthermore he added that
prolonged stress (chronic stress) can be very damaging.
The way Selye gathered these results was by doing experiments on rats
and seeing how they responded to different types of stress. He noticed
that there was a pattern in how the rats and hospital patients
similarly responded to stress. This pattern was a typical syndrome
called 'The General Adaptation Syndrome
GAS consisted of 3 stages; alarm
reaction, resistance stage, and
exhaustion. The body returns back to its normal functioning after the
alarm reaction and exhaustion stage only happens when stress is
The first stage of GAS is the 'Alarm Reaction Stage'.
During this stage there is an increase in activity in the
sympathetic-adrenal-medullary system (SAM) and the
hypothalamic-pituitary-adrenocortical axis (HPA).
These are the 2 main pathways.
In the SAM the hypothalamus sends the message down the sympathetic
branch to the autonomic nervous system (ANS) and to the Adrenal
Medulla. Adrenaline and Noradrenalin is then produced.
The other pathway, HPA, is when the hypothalamus is stimulated and
messages are sent to the pituitary gland and adrenocorticotrophic
hormone (ACTH) is released into the bloodstream. This then stimulates
the Adrenal Cortex which release which releases corticosteroids. This
'fight or flight' response returns the body in its normally function
The second stage is the 'Resistance Stage'.
It is when the body is adapting to the demands of the environment. It
can be when the body is in short term
stress or prolonged stress. When
the body is in short term stress, it undergoes homeostasis which is
"when the body's internal environment generally remains almost
constant in spite of large changes in the external environment"
(psychology pg. 117). Basically it's the body returning into its
normal state at a steady rate.
Also, the body tries to reabsorb excess resources such as coritsol,
glucose, adrenaline or noradrenalin.
However, in chronic stress, hormones are still above baseline levels
and cortisol production increases in the body. This effects the immune
system because number of white cell production is reduced and the
stage may carry on to the final stage.
The final stage is 'Exhaustion stage'.
This only happens when stress is prolonged, demands of the body exceed
the supply and the other 2 stages are ineffective.
The level of stress hormones cannot restore to homeostasis causing the
body's tissues to wear and tear, endocrine glands being damaged and
adrenal glands to be enlarged.
The ANS symptoms reappear which are increased heart rate, sweating,
muscle tension, breathing faster, salivation decreasing, pupils
dilating and so on.
Long-term physical effects of this are the increase in chance of
stress related diseases such as high blood pressure, heart disease and
production of hormones such as testosterone and progesterone
Hans Selye's research may have been successful in the fact that he
showed the significance of the role of the HPA axis in stress.
He notified the importance and effects of stress medically and in
diseases whilst other researchers have not been able to properly prove
the negative effects of chronic stress.
However, Selye's work was very limited as there were several
He did not pay much attention to the SAM system and its role in stress
and did not really understand the link or relationship of the HPA and
In addition, Selye's idea that stress always produces the same
physiological pattern was extravagant as a researcher called Mason
compared the responses to varying stressors with differences of how
much fear, uncertainty or anger they created. The varying stressors
produced different patterns of adrenaline, noradrenaline and cortisol
secreted in the body.
It must also be criticized that Selye used non-humans (rats) for his
research on human response to stress. This could have lead to some of
his errors as rats may not respond in the same psychological way as
humans. He may have used rats for ethical purposes and even if humans
were used for the research, it could be argued that it was for medical
purposes so it could not have been unethical anyway.
Finally it has to be taken in account that the tests Selye carried out
may not necessarily have the same outcomes in pattern for all people
as all people have individual differences. Therefore the way in which
one person reacts to one stress may vary from the way another person
may react to the same stressor. Different levels of hormones may be
produced and the patterns may differ with different people due to how
they perceive and cope with the stress.