The physiology of stress
The process of adapting to stress is called the general adaptation syndrome
(Selye, 1036);
- alarm reaction ---> shock, body’s resources are drained before quickly
recovering in preparation for flight or fight
- resistance ---> adapts to stressful environment by resisting the stressor,
physiological activity is greater and uses a lot of energy (body seems to be
coping but the resources are being used up at a potentially harmful rate and
parasympathetic nervous system is activated to conserve energy)
- exhaustion ---> adaptation to chronic stress is failing, resources drained,
resistance plummets, immune system compromised (individual experiences
stressor from first stage, eg. sweating, panic)
Evaluation;
- research support; Seyle’s research with rats, subjected them to various
stressors ---> response appeared between 6 to 48 hours and Seyle was able
to record resistance/exhaustion responses
- GAS may not be general; Mason replicated the study with monkeys and
found that outcomes depended on the stressor eg. cold conditions resulted in
higher cortisol levels
Acute stress ---> sympathomedullary pathway (SAM)
- also called the flight or fight response
- ANS works with endocrine system during a stressful event and triggers the
flight of fight response
- triggers the hypothalamus which activates the pituitary gland
- ANS changes from parasympathetic state (normal resting state) to the
sympathetic state
- adrenaline; stress hormone released from the adrenal medulla and triggers
physiological changes necessary to fight or flight
- response is immediate and automatic as soon as stressful event occurs
- parasympathetic action; it's antagonistic to fuel sympathetic system + acts as
a brake to reduce activities in the body that were increased by the response
Chronic stress ---> hypothalamic-pituitary-adrenal system (HPA)
- HPA takes longer than the SAM to be activated by a stressor but can
persist for longer
- when the hypothalamus is activated it sends a signal to activate the
sympathetic nervous system
- produces a hormone called corticotropin releasing factor (CRF) which is
detected by the anterior lobe of the pituitary gland
- causes the release of adrenocorticotropin (ACTH) which is detected by the
adrenal cortex and secretes the hormone cortisol in response
Cortisol ---> stress hormone
- help the body cope with a stressor
- eg. glucocorticoids help with glucose metabolism which replenishes supplies
,Negative feedback loop;
- HPA is self regulating via a negative feedback loop
- higher levels of CRF and ACTH result in lower levels of corresponding
reduction in cortisol
Evaluation;
- practical value; people with Addison’s disease cannot produce cortisol and
this can be treated with daily cortisol injections ---> real world application
- ignores psychological factors of stress; cognitive appraisal ---> figuring out
if a stressor is a threat (students watching gruesome medical procedure,
stress depended on whether they inferred the stress to be real or not)
The role of stress in illness
Immunosuppression is the prevention of the efficient functioning of the immune
system is caused by stress
Kiecolt-Glaser’s research;
Study 1 ---> investigated the effect of exams on 75 medical students
- gave 2 blood samples, one right before the exam (high stress) and one that
was a month before the exam (low stress)
FINDINGS
- researchers found that the activity of NK and killer T cells decreased
between the first and second samples ---> evidence of the immune system
being suppressed by chronic stress
- decline most apparent in students who reported stress from other life
events
Study 2 ---> longitudinal study where the health of caregivers vs non-caregivers
were studied
- consisted of participants who were caregivers to people with Alzheirmers
FINDINGS
- over a period of 13 months the caregivers showed a weaker cell based
immune response
- caregivers had higher levels of depression (32% compared to 6% in the
control group)
Evaluation;
- stress can be protective instead of damaging; Dharbar experimented on
rats by subjecting them to acute stressors and found that this caused immune
cells to flood into the bloodstream ---> conflicts with original research
- real world application; reduced levels of adrenaline and noradrenaline
before surgery to reduce anxiety or stress levels + causes recovery to be
faster as it stimulates the immune system
Cardiovascular disorders are disorders that affect the functioning of the heart
, Acute stress research; Lampen (2008)
- looked at incidences of heart attacks in German football supporters during the
1996 world cup
FINDINGS
- when Germany played, cardiac attacks increased by 2.66% compared to a
control group
Chronic stress research; Yusuf (2004)
- examined chronic stress in the INTERHEART study, across 52 studies to
identity major risk factors for cardiovascular disease
- used 15,000 participants
FINDINGS
- workplace stress and stressful life events seemed to have a greater link
to cardiovascular diseases than smoking or obesity
Evaluation;
- role of stress on cardiovascular disease may be indirect; research found
that marital stress tripled the likelihood of a heart attack in women who
already had cardiovascular disease which means that it depends on the
presence of a vulnerability for stress to trigger illness
- research support to link stress to cardiovascular diseases; Song (2019)
identified over 130,000 people with stress related disorders and compared it
with controls (unaffected siblings) and found there was a 64% greater risk of
cardiovascular disease in the first group
Sources of stress: life changes
Life change; significant and rarely infrequent events in people’s lives that cause
stress
- psychological adjustment is needed to adapt to life changes
The greater the change ---> the greater adjustment needed
- not always negative; can bring excitement eg. marriage
Life changes and illness;
- social readjustment rating scale (SRRS) by Holmes and Rahe
- higher the life changing units (LCU), the more psychological adjustment
needed
- research was retrospective; participants ticked off all the life changes they
experienced in the last 12 months
- eg. divorce was 73 LCUs
- eg. death of a lover was 100 LCUs
- under 150 LCUs ---> reasonable health
- 150-200 LCUs ---> 50% had illness in the next year
- 230+ LCUs ---> 80% had illness in the next year
The process of adapting to stress is called the general adaptation syndrome
(Selye, 1036);
- alarm reaction ---> shock, body’s resources are drained before quickly
recovering in preparation for flight or fight
- resistance ---> adapts to stressful environment by resisting the stressor,
physiological activity is greater and uses a lot of energy (body seems to be
coping but the resources are being used up at a potentially harmful rate and
parasympathetic nervous system is activated to conserve energy)
- exhaustion ---> adaptation to chronic stress is failing, resources drained,
resistance plummets, immune system compromised (individual experiences
stressor from first stage, eg. sweating, panic)
Evaluation;
- research support; Seyle’s research with rats, subjected them to various
stressors ---> response appeared between 6 to 48 hours and Seyle was able
to record resistance/exhaustion responses
- GAS may not be general; Mason replicated the study with monkeys and
found that outcomes depended on the stressor eg. cold conditions resulted in
higher cortisol levels
Acute stress ---> sympathomedullary pathway (SAM)
- also called the flight or fight response
- ANS works with endocrine system during a stressful event and triggers the
flight of fight response
- triggers the hypothalamus which activates the pituitary gland
- ANS changes from parasympathetic state (normal resting state) to the
sympathetic state
- adrenaline; stress hormone released from the adrenal medulla and triggers
physiological changes necessary to fight or flight
- response is immediate and automatic as soon as stressful event occurs
- parasympathetic action; it's antagonistic to fuel sympathetic system + acts as
a brake to reduce activities in the body that were increased by the response
Chronic stress ---> hypothalamic-pituitary-adrenal system (HPA)
- HPA takes longer than the SAM to be activated by a stressor but can
persist for longer
- when the hypothalamus is activated it sends a signal to activate the
sympathetic nervous system
- produces a hormone called corticotropin releasing factor (CRF) which is
detected by the anterior lobe of the pituitary gland
- causes the release of adrenocorticotropin (ACTH) which is detected by the
adrenal cortex and secretes the hormone cortisol in response
Cortisol ---> stress hormone
- help the body cope with a stressor
- eg. glucocorticoids help with glucose metabolism which replenishes supplies
,Negative feedback loop;
- HPA is self regulating via a negative feedback loop
- higher levels of CRF and ACTH result in lower levels of corresponding
reduction in cortisol
Evaluation;
- practical value; people with Addison’s disease cannot produce cortisol and
this can be treated with daily cortisol injections ---> real world application
- ignores psychological factors of stress; cognitive appraisal ---> figuring out
if a stressor is a threat (students watching gruesome medical procedure,
stress depended on whether they inferred the stress to be real or not)
The role of stress in illness
Immunosuppression is the prevention of the efficient functioning of the immune
system is caused by stress
Kiecolt-Glaser’s research;
Study 1 ---> investigated the effect of exams on 75 medical students
- gave 2 blood samples, one right before the exam (high stress) and one that
was a month before the exam (low stress)
FINDINGS
- researchers found that the activity of NK and killer T cells decreased
between the first and second samples ---> evidence of the immune system
being suppressed by chronic stress
- decline most apparent in students who reported stress from other life
events
Study 2 ---> longitudinal study where the health of caregivers vs non-caregivers
were studied
- consisted of participants who were caregivers to people with Alzheirmers
FINDINGS
- over a period of 13 months the caregivers showed a weaker cell based
immune response
- caregivers had higher levels of depression (32% compared to 6% in the
control group)
Evaluation;
- stress can be protective instead of damaging; Dharbar experimented on
rats by subjecting them to acute stressors and found that this caused immune
cells to flood into the bloodstream ---> conflicts with original research
- real world application; reduced levels of adrenaline and noradrenaline
before surgery to reduce anxiety or stress levels + causes recovery to be
faster as it stimulates the immune system
Cardiovascular disorders are disorders that affect the functioning of the heart
, Acute stress research; Lampen (2008)
- looked at incidences of heart attacks in German football supporters during the
1996 world cup
FINDINGS
- when Germany played, cardiac attacks increased by 2.66% compared to a
control group
Chronic stress research; Yusuf (2004)
- examined chronic stress in the INTERHEART study, across 52 studies to
identity major risk factors for cardiovascular disease
- used 15,000 participants
FINDINGS
- workplace stress and stressful life events seemed to have a greater link
to cardiovascular diseases than smoking or obesity
Evaluation;
- role of stress on cardiovascular disease may be indirect; research found
that marital stress tripled the likelihood of a heart attack in women who
already had cardiovascular disease which means that it depends on the
presence of a vulnerability for stress to trigger illness
- research support to link stress to cardiovascular diseases; Song (2019)
identified over 130,000 people with stress related disorders and compared it
with controls (unaffected siblings) and found there was a 64% greater risk of
cardiovascular disease in the first group
Sources of stress: life changes
Life change; significant and rarely infrequent events in people’s lives that cause
stress
- psychological adjustment is needed to adapt to life changes
The greater the change ---> the greater adjustment needed
- not always negative; can bring excitement eg. marriage
Life changes and illness;
- social readjustment rating scale (SRRS) by Holmes and Rahe
- higher the life changing units (LCU), the more psychological adjustment
needed
- research was retrospective; participants ticked off all the life changes they
experienced in the last 12 months
- eg. divorce was 73 LCUs
- eg. death of a lover was 100 LCUs
- under 150 LCUs ---> reasonable health
- 150-200 LCUs ---> 50% had illness in the next year
- 230+ LCUs ---> 80% had illness in the next year
