How does the theory of Allostasis further our understanding of the links between health and stress Flashcards
Allostasis (Sterling & Eyer 1988)
Stability through change. Adaptive systems enable response to different physical states, cope with noise, overcrowding , extremes of temperature and infection.
Allostatic systems
Include autonomic nervous system and HPA axis- promote change & enable adaptation.
Allostatic Load
imbalance in allostatic systems - overworked; fail to shut off; fail to respond to initial challenge
Allostatic Systems in relation to stress McEwan 1998 & McEwan 2009
Allostatic systems:
These include autonomic nervous system and the HPA axis. Stress signals the autonomic nervous system to release adrenaline and noradrenaline.
A release of corticotropin-releasing hormone (CRH) from the hypothalamus signals the pituitary gland to produce adrenocorticotropic hormone (ACTH), which in turn signals the adrenal glands to increase the production of cortisol. An increase in cortisol allows an individual to deal with a stressful event.
When chronic an individual is exposed to chronic stress, wear-and-tear is caused to the body, creating allostatic load (McEwan, 1998). When this amount of stress is accumulated over time, the allostatic systems become overworked, meaning they fail to shut off and respond to the challenges
Damage to these systems can lead to high cholesterol, heart problems, damage to haemoglobin and the hippocampus, etc. (McEwan, 2009).
What is Stress (Cohen & Herbert 1996)
Stress is when demands by imposed by events exceed an individual’s ability to cope’
Stress can be activated by certain characteristics such as:
Unpredictable – Uncontrollable – Social Evaluative Threat – Time Pressure
Stress can be acute (stressful day) or Chronic (Long term)
Gallagher & Caroll (2009)
In older populations, caregiving for a spouse withdementiahas been associated with a poorantibody responseto vaccination.
Parents caring forchildren with developmental disabilitiesexhibited a poorerantibody responseto a pneumococcal vaccination then parents caring for typically developing children at both 1-month and 6-month follow-ups.
Flight or Fight Response
With regard to stress, the sudden occurrence of danger, as for a gazelle being chased by a lion or a person confronted by a threat to physical safety, calls forth release of both adrenalin and adrenocortical hormones (“fight or flight” response) that help the body survive the immediate crisis.
Indeed, new research has reinforced the fact that the so‐called “stress mediators” have protective and adaptive as well as damaging effects,
Hagan (2009) Extra Reading
Negative relationships in the family-of-origin predict attenuated cortisol in emerging adults
Negative families exhibited lower salivary cortisol
Findings show the significance of early relationships on long term activity of the HPA axis.
Miller (2013) Extra Reading
Low cortisol reactivity to stress was associated with a higher concurrent BMI among preschool aged, low income children
Blunted cortisol response to stress is often seen following stress exposure, associated with BMI score in very young children.
Further work is needed
Model of Chronic and Acute Stress
Model of Chronic and Acute Stress
LOW SES serves as chronic stressor
Associated with - NK cell counts and higher plasma IL-6 concentration
Increased cortisol,
C Reactive increases in response to inflammation
Also Long term psychosocial factors and genetics can lead to Atherosclerosis
This then leads to Acute Coronary Syndromes which can result in death.
Acute Psychological Stress
Evidence from Lab studies increases biological responses
Characteristics of Acute stress are severe anxiety & witnessing death
Evidence from clinical studies has shown acute stress can lead to acute coronary syndromes
Social Support in relation to stress
Stress, allostasis and allostatic load =
Theory of adaptation and resistance
or…
a tale of two important concepts: vulnerability versus resilience
PNI in relation to Allostasis (Lutgendorf & Costanzo (2000)
3 Psychosocial factors which accumulate to life stress.
This all accumulates to Physiological responses which lead to health outcomes.
Where as in terms in resilience, social support acts as a buffer.
Relate to the amount of vulnerabilities there are compared to stress protective factors.
There are many factors which can lead to vulnerability such as SES, depression or sex, age and ethnicity or-behaviours such as smoking, sleep, diet and exercise.
3 Fs Flight - Fight - Fright
Elaborate
General Adaptation Theory
Alarm reaction –> Resistance –> Reaction
An PNI evidence of fetal programming
Longer term/prospective studies have found effects across childhood and into adolescence:
Longer term/prospective studies have found effects across childhood and into adolescence:•Infancy e.g. Huizink et al, (2003) - stress (hassles) in early pregnancy (15-17 wks) and fear of giving birth (27-28 wks) linked to impaired mental and motor development and to reduced attention and adaptability at 8 months.
