1 Is the biological response to a demand that threatens an organism.
2 The sympathetic branch of the autonomic nervous
system is activated ready for the 'fight or flight' response.
2.1 If the stressor 'stands down' at any
time during the physiological response,
the parasympathetic nervous system is
employed to return the body to its
normal homeostatic state.
3 The General Adaptation Syndrome (GAS)
3.1 1. ALARM - Activation of pituitary-adrenal
and sympathomedullary system. Heart rate
increases breathing and energy levels
increase preparing for 'fight or flight'.
3.1.1 2. RESISTANCE STAGE - Body changes and
adapts to continued stressor. Body appears to
return to normal, but arousal levels are still high.
Body, under continued stress, starts to run out of
resources (e.g. long-term use of hormones).
126.96.36.199 3. EXHAUSTION - If stress continues, body's
resources deplete and it can no longer cope with
the stress. Immune system loses efficiency and
illness may result. In Selye's studies, many animals
3.2 Strengths - The model has resulted in a better understanding
of the physiological effects of stress. It is useful in the
prediction of the physiological response to stress. It can be
applied to other areas, such as the link between athletes
suffereing from injury/stress and recovery time. There has been
a raised awareness of the stress in animals kept in captivity,
with the introduction of animal enrichment programmes.
3.3 Limitations - The results may not be applicable to
humans because animal physiology may be different. We
are not aware of animals' perception of stress. The
research was ethically improper as the animals suffered.
4 Stress-related Illness And The Immune System
4.1 Coronary Heart Disease and Stress
4.1.1 Based on research by Rosengren et al. (1991)
188.8.131.52 Higher blood pressure is
a response to stress and
damage could result.
184.108.40.206 Long-term stress may mean
blood vessels in the heart.
220.127.116.11 Stress hormones increase fatty
deposits on the artery walls.
4.2 Stress and The Immune System
4.2.1 The white cells are the first barrier.
4.2.2 T-cells in turn attack
anything that carries disease
and produce B-cells to
destroy the carrier cells.
4.2.3 Stress can cause the
immune system to be
suppressed, leaving the
body vulnerable to illness.
4.2.4 Key Study : Kiecolt-Glaser et al. 1984
18.104.22.168 Aim: To see if the immune
system is affected by
22.214.171.124 Procedure: Students gave a blood
sample a month before the exams (low
stress time) and again during the exam
period (high stress time). The samples
were tested for T-cell content.
Students also filled out a questionnaire
about loneliness and lifestyle factors.
126.96.36.199 Findings: During the exam period it was
found that the students had fewer killer
cells to deal with incoming disease.
188.8.131.52 Conclusion: Stress is a key factor in
the lowering of the immune system.
184.108.40.206 Pros - As a natural experiment, it has high
ecological validity - the exams were real-life
experiences. It was a correlational study, so
cause and effect could not be ascertained. Cons
- Those who suffered more stress seemed to
have other external stressors such as loneliness.
5 Life Changes and Daily Hassles
5.1 Key study: A study of life changes
using the Social Readjustment Rating
Scale (Holmes and Rahe 1967)
5.1.1 Aim: To develop a rating
scale to quantify the amount
of stress in people's lives
that will produce illness.
5.1.2 Procedure: Participants were
asked to tick the events that they
had experienced over a past
period of two years. Many people
were asked to rate life events in
terms of the amount of
readjustment they would have to
make to the psychological impact
of those events. The highest
rated was the death of a spouse,
and was given an arbitary value
of 100 (life change units);
redundancy came out at 47. The
scores were then totalled.
5.1.3 Findings: The higher the score of
the participant, the higher the
odds of that participant
developing stress-related illness.
5.1.4 Conclusion: Stress can be
objectively measured and
there is a positive
relationship between the
number and level of life
changes and the risk of
5.1.5 Criticisms: Pros - The scale has been used in over
1000 studies, showing a positive relationship
between scores and physical illness. The rating
scale did show that positive events can cause
stress as well as negative ones, but it did not
differentiate between the two and assumed that any
life change was stressful (pro & con). This was the
first time that levels of stress in people's lives had
been quantified. The study confirmed that life events
could lead to health breakdown. Cons - It showed a
correlational relationship between life events and ill
health, but casuality cannot be assumed.
Self-reporting is not reliable. The study did not take
into account individual differences - we may
percieve life events differently (some may find
divorce stressful while others are relieved). It
assumed adult experiences and cannot be applied
5.2 Key Study: The naval study (Rahe et al. 1970)
5.2.1 Aim: To see if stress and
illness are related to each other.
5.2.2 Procedure: US male naval personnel who
were away from home on a tour of duty
for six months were asked to complete the
Social readjustment Rating Scale. They
were then monitored over the six months in
order to see if illness developed.
5.2.3 Findings: They found that higher
totals of life change unit scores
correlated with increased illness.
5.2.4 Conclusion: A relationship between
illness and life changes can be assumed.
5.2.5 Criticisms: Pros - The study
showed some support for life
changes prior to duty affecting
health. Cons - The correlation was
very weak and, in other
circumstances, there may be no
correlation. All the participants were
male and sailors, making it difficult
to generalise from the findings.