To some extent all parts of the nervous system, the endocrine system, and the body, are involved in the stress response. The brain is involved in perceiving and interpreting an event as a stressor and organising and initiating the stress response. It directs the autonomic nervous system and the endocrine system (the system of glands which secretes hormones into the bloodstream) to respond to a stressor. It also directs motor responses such as running, for example, a visit to the zoo, when you see a lion pacing up and down its cage, you would be unlikely to see the situation as dangerous and simply walk on by, but a safari holiday in Africa, a lion comes charging towards you, you would in all likelihood, interpret the event as a stressor and make an appropriate stress response which would involve physiological changes and activity – in all probability, flight.
The hypothalamus and pituitary gland play an important part in the stress response. The hypothalamus activates the sympathetic branch of the autonomic system. The sympathetic branch produces many of the physiological changes involved in the stress response, for example, accelerating the heart rate and dilating the pupils.
In response to a stressor the hypothalamus stimulates the pituitary gland to secrete ACTH, the body’s major stress hormone. The adrenal gland is stimulated by both the sympathetic branch of the autonomic nervous system and the pituitary gland to secrete hormones which activate the stress response.
Stress can occur as short term or long term. Short term stress refers to a sudden burst of energy and emotional feelings in response to situations which are seen as emergencies. It may result in a spurt of activity in order to deal with the emergency. Short term stress is generally considered far less dangerous than, long term stress. Long term stress can occur either when a stressor is prolonged, for example, long term exposure to cold or because several stressful events occur one after the other. Long term stress is sometimes known as chronic stress. Long term stress can result in poor concentration, poor memory and a lack of clear thinking.
The term stress was introduced into psychology in the 1950’s by Hans Seyle. He was the first researcher to make detailed studies of the physiological changes that take place under short term or long term stress. Much of his research was based on experiments with laboratory animals. Based on the results of his experiments Seyle argued that all stressors, no matter how different they are, produce much the same action, the same general bodily response. He therefore defined stress as ‘the non specific response of the body to any demand made upon it’ (Seyle 1956). Seyle’s model of the stress response is known as the General Adaptation Syndrome (GAS). Seyle identified three main stages in the stress response.
The first stage, the alarm reaction, mobilises the body for swift action such as Cannon’s fight or flight response. It occurs over seconds or minutes in the face of a sudden stressor. Various reactions happen within the body to enable the body to either stay and fight or run away from the stressor. The second stage, the resistance stage occurs when a stressor is resistant. The resistance stage can harm health, for example, it can reduce the effectiveness of the immune system so lowering the body’s resistance to disease.
The last stage, the exhaustion stage, is reacted when a stressor persists still longer, and the body’s defences can no longer cope. Illness is the cost of an unsuccessful defence against long term stress. In extreme cases it can result in death.
The General Adaptation Syndrome has been extremely influential. In particular, it has identified a link between psychological factors and physical illness. Many common stressors such as unemployment, marital conflict, preparing for an examination and the death of a close relative are associated with the stress responses outlined in the GAS. These stressors are often accompanied by the physiological changes described by Seyle and sometimes result in the psychosomatic illnesses he identified.
It has been criticised that people do not always respond in the same way to stressors and the experience of stress. Seyle largely ignored the importance of individual differences. People interpret different stressors differently. They may see it as having little or no effect on them, as mildly stressful or extremely stressful. They also differ in their assessment of their ability to cope with a stressor. Some may feel that they can cope quite well but others may feel that they cannot cope at all. All these interpretations and assessments would affect every stage of the GAS. In this respect Seyle ignored the psychological aspects of stressors and stress response. Seyle claimed that all stressors produce the same physiological response. However, there is evidence to suggest that there are specific stressors, for example, stressors which lead to anxiety appear to result in the release of more adrenaline than noradrenalin, and the stressors which lead to aggression appear to result in the release of more noradrenalin (Cox 1978). This suggests that Seyle overstated his case.
A large number of studies have indicated a link between stress, the immune system and illness. They suggest that stress reduces the efficiency of the immune system which lowers the body’s resistance to disease. Studies of men and women who have recently been divorced or separated – often an extremely stressful experience – indicate poorer functioning of the immune system compared with married couples of similar age and social position, for example, immune cells from divorced people did not reproduce as effectively as those from their married counterparts (Keicolt – Glaser et al, 1987).
A number of studies have looked at the relationship between taking examinations and the functioning of the immune system. These studies indicate that the stress of examinations reduces the effectiveness of the immune system, for example, one study examined 40 medical students 6 weeks before their exams and again during their exams. The students revealed higher levels of stress during their exams and the percentage of T cells showed significant reductions at exam time (Glaser et al, 1986).
This has been criticised because the immune system may be affected by a whole range of factors in people’s lives. These include drugs, alcohol, nicotine and caffeine, a person’s general health, their diet, physical activity, sleep patterns, age and medication. Although many studies attempt to control for such factors in order to isolate the effect of stress, complete control is unlikely (Keicolt-Glaser & Glaser 1988). In voice of the complexity of the immune system, these findings are suggestive rather than conclusive – in other words we cannot be certain that stress suppresses the immune system.
A number of studies indicate that the physiological stress response to life events may increase the risk of coronary heart disease (CHD), one study looked at negative life events over a period of 1 year – events such as divorce and the death of a close friend. These events were accompanied by rises in blood pressure and the production of fatty acids which leads to an increase in blood cholesterol. These increase the risk of CHD.
A number of studies have looked at stress at work in relation to CHD, for example, people with low status occupations have been linked to high blood pressure and high blood cholesterol, both of which increase the risk of CHD (Evans, 1998). The evidence for a link between stress and CHD is not simple and clear cut. Some of the research is contradictory. This may be partly due to the difficulty of measuring vague concepts such as stress, hostility and cynicism. Despite these problems, the weight of evidence does suggest a link between stress and CHD.
Positive and negative life events are seen as desirable and undesirable. A number of researchers argue that life events are a major source of stress. The most famous application of this idea is the Social Readjustment Rating Scale (SRRS) devised by Holmes and Rahe (1967). They argued that whenever an individual had to make ‘a substantial adjustment to the environment the likelihood of stress is high’. Holmes and Rahe began their research by examining the medical records of 5000 people. They selected 43 life events and asked a sample of 394 people to rate the degree of social readjustment required for each event. Based on the results they constructed the SRRS. Each life event was ranked and assigned a number of life change units from 100 to 11. A person’s stress score is the sum of all the life change units for events they have experienced within a 12 month period.
The advantages of the SRRS are that it offers a simple, straightforward measure of stress. It is quick and easy to administer and it is easy to score. If the SRRS is an effective instrument for measuring stress then the higher the individuals stress score, the greater their risk of illness. Many studies have claimed to have found this relationship.
The disadvantages of the SRRS is that the 43 life events on the SRRS may be perceived very differently by different people and information about life events is usually collected at least 6 months and often up to 18 months after the events have happened. Asking people to recall events may produce invalid data. They may simply forget.
Major life events do not happen every day by daily hassles do. Daily hassles are the ‘irritating, frustrating, distressing demands that to some degree characterise everyday transactions with the environment’. (Kanner et al, 1981). A number of researchers argue that daily hassles lead to more stress and have a greater impact on physical and mental health than life events. In one study using a hassles scale of 117 items, 100 middle aged adults completed the scale each month, for 9 months. They also completed the SRRS life events scale. Hassles scores were a better predictor of psychological problems, such as, depression and anxiety, than life events scores (Kanner et al, 1981).
The daily hassles scale has some of the same problems as the SRRS. The link between hassles and psychological and physical disorders is correlational. It is therefore difficult to separate cause from effect.
There are many ways of coping with stress a few of these are antianxiety drugs and antidepressant drugs, which can reduce the effects of stress. Biofeedback is a method used to help people control their stress by making them aware of the bodily processes and how to measure them. People can attend stress management programmes to help reduce stress and improve coping skills.
REFERENCES
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Cannon, W.B. (1932). The Wisdom of the Body. New York: Norton as cited in Rice, D, Haralambos, M (Ed) (2000) Psychology in Focus, AS Level, Lancashire, Causeway Press Limited
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Keicolt – Glaser, J.K., Fisher, L., Ogrocki, P., Stout, J.C., Speicher, C.E. & Glaser, R. (1987). ‘Marital Quality, Marital Disruption and Immune Function’ Psychosomatic Medicine, 49, 13-34 as cited in Rice, D, Haralambos, M (Ed) (2000) Psychology in Focus, AS Level, Lancashire, Causeway Press Limited
Glaser R., Rice, J., Speicher, C.E., Stout, J.C. & Keicolt-Glaser, J.K. (1986) ‘Stress Depresses Interferon Production by Leukocytes Concomitant with a Decrease in Natural Killer Cell Activity’ Behavioural Neuroscience, 100, 675-678 as cited in Rice, D, Haralambos, M (Ed) (2000) Psychology in Focus, AS Level, Lancashire, Causeway Press Limited
Keicolt-Glaser, J.K. & Glaser, R. (1988) ‘Methodological Issues in Behavioural Immunology Research with Humans’ Brain, Behavioural and Immunity, 2, 67-78 as cited in Rice, D, Haralambos, M (Ed) (2000) Psychology in Focus, AS Level, Lancashire, Causeway Press Limited
Evans, P. (1998). ‘Stress and Coping’ in M. Pitts & K. Phillips (Eds.), The Psychology of Health: An Introduction. London: Routledge as cited in Rice, D, Haralambos, M (Ed) (2000) Psychology in Focus, AS Level, Lancashire, Causeway Press Limited
Holmes, T. H. & Rahe, R. H. (1967). ‘The Social Readjustment Rating Scale’ Journal of Psychosomatic Research, 11, 213-218 as cited in Rice, D, Haralambos, M (Ed) (2000) Psychology in Focus, AS Level, Lancashire, Causeway Press Limited
Kanner, A.D., Coyne, J.C., Schaeffer, C. & Lazurus, R.S. (1981). ‘Comparison of two modes of stress measurement: Daily Hassles and Uplifts Versus Major Life Events’ Journal of Behavioural Medicine, 4, 1-39 as cited in Rice, D, Haralambos, M (Ed) (2000) Psychology in Focus, AS Level, Lancashire, Causeway Press Limited
