This essay will define stress and stressors. It will also explain the how stress can affect an individuals and outline and evaluate the at least two models of stress. It will explore how stress can be measured and outline and evaluate two models of stress and stressors.
Stress is a pressure or force exerted on an object according to engineers and physicians (Gross r,Mcilveen r and Cooligan2000). Lazarus and folkman (1984) define stress as “a pattern of negative physiological states and psychological response occurring in a situation where people perceive threats to their well-being which they may be unable to meet” (Grossr,Mcilveen r and Cooligan 2000). There are different views of stress. Stress as a “stimulus” which means it is applied to the person or stressor and it is in the environment. This relates to the engineering model of stress identified by Cox (1978)(blackboard).secondly stress is seen as a “response”, the body identifies stress as a reaction made within the body(Blackboard).Selye 1956 defines stress as “the non-specific response of the body to any demands made upon it” this relates to the physiological model of stress(Blackboard). Finally stress is viewed as an interaction, in this view stress is seen as a transaction between environment and the individual and this relates to the “transactional model of stress” (Blackboard). The ability to cope with stress and the meaning people give to stressors will define the stress experienced (Blackboard).How people react and what causes stress will differ because of individual differences. However not all stress is bad for you. “Eustress” refers to positive and pleasant stress where we experience good performance and the ability of coping with increased demand (Blackboard).
A stressor is an event or demand that creates or triggers stress response, a stressor forces the body to respond and throws the body out of balance (Gross r,Mcilveen r and Cooligan 2000). Stressful events are called stressors examples include environmental stressors, work stressors, life changes and daily hassles. All this events might be stressful, however not two people react to stress the same way. The moderator which means the individual differences that will determine the extent of stress perceived. What determines if an event is a stressor is how the event is perceived.
Stress affects individuals in different ways. There are two major systems in the body that stress response action involves (hand-out). This is the nervous system whereby we also see the sympathetic adrenal medullary (SAM) and the endocrine system where we also find the hypothalamic pituitary adrenal (HPA). This is the physiological reaction to stress. The nervous system is divided into two parts central and peripheral nervous system (CNS and PNS) (Hand-out). The CNS has neurons in the spinal cord and the brain and is responsible for thoughts and behaviour. While the PNS which has neurons outside the spinal cord and brain carry information to and from the body (hand-out). Part of the PNS is the automatic nervous system (ANS) which plays an important role in stress. It controls involuntary aspect of behaviour and operates automatically (hand-out). The ANS consist of two parts the sympathetic branch which is responsible for arousing the body and the parasympathetic branch which is responsible of returning the body to a normal state (hand-out). For example the sympathetic branch will increase heart rate while the parasympathetic branch will decrease the heart rate.
SAM pathway uses electricity and the communication along the nerve fibres are very fast (hand-out). How it works and contributes to stress is the hypothalamus activates the sympathetic branch which sends signals to adrenal medulla which in response releases adrenaline and noradrenaline which then contributes to stress by increase in blood pressure, heart rate and sugar level (hand-out). Other activities triggered by the sympathetic branch to increase stress hormones are respiration rate increases to supply oxygen muscles, muscles will be tensed for preparation for response like running (Gross r, Mcilveen r, and Cooligan 2000).HPA pathway is a chemical based system and not as fast as SAM and is a mechanism that prolongs stress response (hand-out). The hypothalamus in the brain gets the body ready for action when a stressor is sensed and signals the pituitary gland to release adrenocorticotrophic hormone (ACTH) (hand-out). Adrenal cortex will then detect ACTH and in response will release corticosteroids. The effects that this will have on the body is helping blood to clot, affect the salt and sugar level in the blood , raise LDL cholesterol which could cause heart attack if it continues(hand-out). Adrenal medulla also releases stress hormones which are important like adrenaline and noradrenaline which will cause “fight to flight” saliva production inhibited, increased heart and breathing rate (Brody r and Dwyer d 2002).
There is large evidence to suggest that stress causes several illnesses. During stressful situation the adrenal cortex will produce hormones which will stop the production of white blood cells which attack virus and hence will affect the immune system (Brody r and Dwyer d 2002). Stress can also be linked to cardiovascular with the function of sympathetic system in hypertension, also when the ANS activity is increased the blood flow in the veins increases causing hardening and deteriorating of blood vessels causing the coronary heart disease (CHD) or stroke (Gross r.Mcilveen r and Cooligan H 2000). The relationship of chronic stress and mental disorder like anxiety and depression is common (hand-out).
However not all individuals react to stress in the same way. Firstly personality determines how people will cope with stress. Friendman and Rosenman (1974) studied personality types and found that personality Type A(TAB) have a higher risk of developing CHD than those with Type B (Blackboard).Type A personality have high cholesterol and adrenaline and their behaviours was time pressured, competitive and hostile (hand-out). While still considering other risk like smoking and drinking 70%of people who died during their research were Type A. (hand-out). However correlation is not causation and the fact that people belong to a certain personality does not mean that will be the cause of an illness. Matthew et al 1977 reviewed the evidence and found out that it was negative and some aspects of TAB like hostility was reasonable and there was no significant link with TAB and CHD (hand-out).Barefoot et al suggest that individuals with high hostility scored 5 times more likely to die before 50(blackboard).TAB may engage in things like smoking and may be psychologically reactive to stress and this could lead to being prone to coronary and there is no difference between TAB and non-TAB in relation to heart attack or death (Gross r. Mcilveen R and Cooligan h 2000).
Stress is experienced differently by both men and women. Men are more likely than women to die of CHD (psychology4a). Researchers show that when performing stressful task women showed lower increase in blood pressure than men (Brody z and Dwyer 2002). Oxytocin hormone makes people less anxious and researchers found female hormone oestrogen makes this hormone more effective while male hormone testosterone reduces the effectiveness of this hormone (psychology4a). Women are more likely to have social support which is important in reducing stress (Brody z and Dwyer 2002).Different cultures experience different levels of stress. While minority try to adapt to majority lifestyle and values they experience “acculturation stress” (Anderson 1991). African-Americans suffer more mental illness than the white-Americans and experience high level of CHD, hassles, life events and racism (Brody z and Dwyerd 2002). Weg(1983) suggested that the long life expectancy of the Russians could be linked to low level of stress within their culture (Psychology4a). Researchers to ethnicity and stress found a variation of stress based on ethnic background hypertension is high among African-Americans (hand-out).Asians ,Blacks and Hispanic are reported to have high level of stress than Whites while Koreans have the lowest stress (Ncbi2004). People react more to stress as they age so we stress can vary because of age. Comparing to whites lower class, African-American lower class will have more stressors in their environment (hand-out).
Selwyn (1950) was the first person to popularise the term stress .Stress is adaptive in short term because it helps us cope with the environment demands of “flight and fight “but the long-term stress or prolonged stress is damaging (hand-out). Selwyn did an experiment with rats whereby he exposed the rats to acute nocuous agents. He found they showed a similar pattern to bodily response with hospital patients and called this pattern General Adaptation Syndrome (GAS). This consisted of three stages alarm reaction, resistance and exhaustion. The alarm stage involves a switch activity in the SAM and HPA pathway and the body responds with increased reactivity like “fight and flight” (hand-out). This reaction occurs 6-48 hours after stress and develops as a response to meet the demand off the stressor (hand-out). It includes the drop in body temperature, decrease of the spleen and liver and loss of muscle (hand-out).The resistance stage is whereby the body is trying to cope with the demand environment and the stressor, as the body resistance to stressor stays high the arousal remains high and the system is pushed to the limit (hand-out). If stress disappears at this stage the body will return to normal but if stress continues it may harm the body (psychology 4a). The exhaustion stage occurs when the stressor is prolonged and the body defence against illness is decreased (Rice D and Haralambous 2000). Individuals will become distressed unable to concentrate and irritable (Brodyz Dwyer R2000) in extreme circumstance death may occur.
The GAS model was based on research and was very influential as it has identified the link between illness and stress. However most of the research was made on rats and may not apply to humans. People differ and do not always respond in the same way (blackboard).Selwyn ignored the physiological response to stress and stressors and without consideration of the effects it has on this like personality in coping with stress (Brody z and Dwyer d 2000).
The transactional model of stress states that “stress result from a transactional between individual and the environment” (Rice d and Haralambous m 2002).individuals interpret the sources of stress to moderate the response (blackboard).Experience of stress on an individual depends on the way the perceive the demand of the stressors or situation and ability to cope and when an individual perception that the demand of the environment is greater than their resources then stress will arise (Rice d and Haralambous m 2002). Lazarus (1976) sees cognitive appraisal as the key to understanding stress and event can become a stressor only when it is perceived as stressful (blackboard). The idea behind cognitive appraisal is to enable individuals to change how they think about certain events. The first appraisal that people make is called primary appraisal whereby the individual decide if an event is neutral ,positive or negative (Rice d and Haralambous m 2002).secondary appraisal is whereby you weigh out if coping abilities and resources are ideal to deal with a situation and overcome it (Rice d and Haralambous m 2002).Transactional model has advantaged because it focus on two area individual differences and factors that influence the level of stress it supports that individual experience stress differently (black board). However, personality is a wide concept and how to measure it is imprecise (blackboard) also some researchers suggest that some events likely to be seen as stressors than others (Rice d and haralambous m 2002).
Stress has been measured in 3 different ways. Firstly the physiological method of which it measures the presence of specific neurotransmitter and the hormone that are linked to the stress response (blackboard). This can be done by taking samples of blood, urine and saliva and the presence of the hormone indicate an activity in the nervous system (Rice d and Haralambous M 2002). Frankenhauser (1975) in doing urine analysis compared the level of adrenaline and noradrenaline to the level of high blood pressure, headaches and intestinal disorder (black board). This method was highly reliable, however measuring hormones does not tell us exactly how the person is stressed and the hormone production will differ depending on what time of the day it is taken (Rice D and Haralambous m 2002). Bearing in mind how the immune system can be complex the level of T cells may not be linked directly to stress (blackboard). Considering that these methods can be invasive and requires expertise other factors may affect the physiological changes (blackboard). The laboratory experiment was used to measure stress and gave an opportunity to control and measure stressors (Rice D and Haralambous m 2002).they used this experiment in both animal and humans. In humans unpleasant experiment was done to induce stress this includes electric shock, exposure to high or low temperature or overcrowding (blackboard). Selwyn 1950 studied on animals by exposing them variety of stressors and measuring their response with these method different stressors could be controlled and isolated (blackboard). However this method only measures stressors and not individual impact and the laboratory was an artificial environment which could not be transferred into reality (blackboard).The experiment also raised ethical issues about treatment of the participants .Also life is not a laboratory and the experience lack external validity and therefore you cannot generalise from the findings as research done on animals. Human beings are capable of rational thoughts which is not true of animals this will affect their potential to control their reaction to stimuli.
Self-report looks at the perception of stress or stressor by an individual (blackboard).individuals will keep diaries and record their daily hassles or stressors over a period of time. Holme and Rahe 1965 used the social readjustment rating scale (SRRS) to rate the level of social readjustment required as a measure of life stressors (blackboard). They used 394 people to rate the 43 specific life events giving each life events a value, some event having higher value than others. They found a relationship between the SRRS score and illness. Although this research was influential they had problems, many people may not have experienced some of the 43 events like death of a spouse. Some people may consider divorce stressful while other may think it is a relief. SRRS research is correlational rather than experimental and does not prove life events have caused serious stress related illness Van os, Park and Jones studied life events in individuals low and high in personality dimension of neuroticism. Found neuroticism assessed at age 16 predicted number of stressful life events experienced 27 years later. Kanner etal 1981 used a scale for measuring “hassles” and “uplifts”, they used 100 adults from 45-65 yrs old to complete the questionnaire. The hassle scale which had 117 items and uplift scale which had135 items were used to find their relationship to health (hand-out). Hassles increased the level of cortisol encouraged habits like smoking. This method can be good because it can be modified for specific groups and also uses a scale which account for individual differences. However, the relationship between hassles and illness is correlational, traffic jams can be used by some as an opportunity to relax. Also there is little evidence which supports uplifts and having positive effects
In conclusion stress is a part of our daily life and although researchers have found the relationship with stress and illness, some stress is actually good for us.
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REFERENCE LIST
Brody,R and Dwyer ,D (2002) Revise psychology for As level ,Hove :psychology press
Gross R Mcilveen , R and Cooligan H (2000).psychology new introduction for As level, Kent :Green gate
NCBI (2004) Race ethnicity and stress, www.ncbi.nlm.nih.gov/books/NBK24685/[accessed 20.02.2012]
Psychology 4a, Stress, psychology4a.com/stress%201.htm[accessed 20.02.2012]
Rice, D and Haralambous, M (2000). Psychology in focus A level, causeway press: Lancashire
BIBIOGRAPHY
Blackboard section on Stress and well being
Hand out (on GAS model)
Hand- out (life changes and hassles)
Hand –out (personality type)