Definitions of Stress
Stress as a response to something in the environment
Stress as a stimulus in the environment - stressor
Stress as a lack of fit between perceived demand and perceived ability to cope with those demands
Pituitary-adrenal response to stress
- Higher brain centres evaluate a situation as stressful
- Hypothalamus is instructed to release CRF
- CRF travels to the pituitary gland
- Pituitary gland release ACTH
- ACTH travels to the adrenal cortex
- Adrenal cortex releases corticosteroids into the blood stream
Sympathomedullary pathway response to stress
- Hypothalamus activates the sympathetic subdivision of the ANS
- Activation of the ANS stimulates the adrenal medulla to release the hormones adrenaline and noradrenaline into the bloodstream
- Heart rate and blood pressure increase, energy reserves are mobilised digestion slows down
The General Adaptation Syndrome
ALARM - response to a perceived threat - stress response
RESISTANCE - body's stress response fully activated
EXHAUSTION - stress-related conditions might develop if the stress is long lasting or chronic
The immune system
The immune system is our main defence against infection by foreign agents. It is a network of cells and chemicals throughout the body.
Phagocytes - surround and ingest foreign particles
Lymphocytes (T cells) - seek out and destroy foreign cells and cells infected with antigens
B cells - produce antibodies which attach themselves to the virus
Stress-response and the immune system
Stress can cause immunosupression due to the chemicals and hormones released as part of the stress response.
E.g. corticosteroids can shrink the thymas gland which produces T cells.
Infection and illness occurs more frequently and it takes longer to recover
ACTH can cause the adrenal glands to release anti-inflammatory hormones
Skin disorders such as eczema worsen
The effects of short term stress on the immune sys
Kiecolt-Glaser et. al.
Blood samples were taken from 75 medical students a) one month before their final exams and b) during their final exams. The students were given a questionnaire to assess psychological variables.
Immune function was assessd by measuring T cell activity in the blood.
T cell activity was significantly reduced in the blood sample taken during the final exams. T cell activity was most reduced in participants who had also reported stressful life events.
The effects of chronic stress on the immune system
Couples whose interactions are negative and hostile show less adaptive immunological responses afer these interactions
Kiecold-Glaser et al
Tested the impact of interpersonal conflict on wound healing.
Blister wounds on the arms of married couples healed more slowly after conflictive than after supportive discussions.
Discrete stressors - life changes
Social Readjustment Rating Scale - Holmes and Rahe
List of major life events
Each event given a score out of 100 - called a Life Change Unit - based on the amount of readjustment they would require
Death of a spouse - 100 LCU
Marriage - 50 LCU
Christmas - 12 LCU
Participants are asked to check off any of the 43 life events they have recently experienced and given a total score
Study of life changes as a source of stress
Rahe et al
2500 male American sailors were given the SRRS to assess how many life events they had experienced in the previous six months. Over the following six months, sailors kept a record of their health. Scores on the SRRS were correlated with sailors' illness scores.
There was a positive coreelation of 0.118 between life change scores and illness scores.
Since the correlation was small, life events cannot be the only factor contributing to illness.
Continuous stressors - daily hassles
Daily hassles are relatively minor events that arise in the course of a normal day.
- Concerns about work
- Too many things to do
- Health of a family member
- Misplacing things
- Concerns about weight/appearance
Daily uplifts are events that offset the effects of daily hassles - positive everyday experiences
- Relating well to spouse/partner/friends
- Feeling healthy
- Completing a task
Research on daily hassles as a source of stress
Kanner et al devised the Hassles Scale consisting of 117 everyday problems. It also included an Uplifts Scale.
Scores on the Hassles Scale correlated with depression, anxiety and health problems to a greater extent than scores on the SRRS
Sources of stress in the workplace:
- Physical environment
- Work overload
- Lack of control
- Role ambiguity
Stress can lead to physical and psychological consequences whivh in turn affect productivity through decreased motivation and time off with health problems.
Study of workplace stress
Studied two groups of workers at a sawmill. One group had a repetetive task of feeding logs into a machine. The environment was noisy and they were socially isolated. The other group had a different job where they had more control and could socialise with others. Stress levels were measured by testing levels of stress related hormones in their urine.
Group 1 had higher levels of stress related hormones in their urine than group 2, suggesting that workplace stressors can trigger the stress response.
Type A Behaviour
Type A behaviour is a particular behaviour pattern associated with increased vulnerability to stress-related illnesses
- Constant time pressure
- Doing several tasks at once
- Being competetive at work and in social situations
- Easily frustrated by others
- Hostile towards others
Research on Type A Behaviour and Stress
Friedman and Rosenman
3200 Californian men were catagorized as either Type A, Type X or Type B. The sample were followed up for 8 and a half years to assess their health outcomes.
257 men developed coronary heart disease. 70% of these were from the Type A group.
This difference was independent of lifestyle factors such as smoking and obesity. So the Type A behaviour pattern increases vulnerability to heart disease.
Hardy personility - Kobasa
Hardiness includes a range of personality factors that defend against the negative effects of stress
- Control - influencing what happens in your life
- Commitment - Engaging in the world around you
- Challenge - viewing life changes as opportunities rather than as threats
Types of coping
Emotion focused - strategies that attempt to regulate emotional distress associated with stressful events. Denial, focusing on emotions, seeking social support
Problem focused - strategies that attempt to do something to actively alleviate or eliminate the stressful situation. Taking control, evaluating pros and cons