In this essay I am going to outline and evaluate research on the effect of stress on the immune system, to do this I will include Glaser’s study on the effects of stress on the immune system, also Selye’s study and finally I will include the methods used to reduce stress. To begin with i will talk about stress, stress is the process that occurs as individuals adjust to or deal with environmental circumstances that disrupt, or even to disrupt their physical or psychological functioning. There are also stressors this is a physical or psychological well being. The immune system on the other hand is a system that protects the body against infection, it also is known as a network of cells and chemicals that seek out and destroy invading particles.
There are many effects of stress on the body, for starters there are short term effects, in this the stress is an emotion and therefore physiological reactions are similar. Also in short term effects the stress activates the hypothalamus and the pituitary in the brain, which stimulates the autonomic nervous system (ANS) and the production of ACTH (adrenocorticotrophic hormone). ACTH leads to production of adrenaline from the adrenal glands located just on the top of both kidneys. The result is ANS arousal which causes increases in heart rate, respiration, sweating and so on.
For long term effects there is a study such as Selye which was done in 1956, this was called the general adaptation syndrome (GAS). Selye describe the model for prolonged stress from observations of his patients. In this he exposes rats to a variety of stressful situations including colds, fatigue, electric shocks and surgical traumas, he noted that whatever the stressor was the rats all reacted in the same way. According to Selye when faced with a stressor the body goes threw three stages. The alarm reaction this is concerned with physiological changes associated with arousal to mobilise the body for action (flight or fight response).
Initially arousal drops below normal and then rapidly rises above normal. The second stage is resistance, in this the body adapts to the stressor and physiological arousal declines, but still remains above normal. Although there are few outward signs of stress now, the person is vulnerable to disease of adaptation such as ulcers and high blood pressures. The third and final stage is exhaustion; here the body cannot maintain high levels of arousal indefinitely and eventually the body energy reserves becomes depleted and the ability to resist stress declines, if stress continues damage and even death can follow. Selye thought that GAS was a non specific responses to any stressor, but in fact different stimuli lead to different respon84ses (stimulus differences). No two people respond in the same way, also the same person does not respond in the same way.
A study which shows the effects of stress on the immune system is Kiecolt Glaser’s study which was constructed in 1984. The aim of this study was to investigate whether the stress of important examinations has an effect on the functioning of the immune system. The procedures which were carried out, was firstly 75 medical students were used in a natural experiment, blood samples were taken one month before there final examinations when there was relatively low stress, and during the examinations when there was relatively high stress, the immune system functions were assessed by measuring the NK cell activity in the blood samples, the students were also given questionnaires to assess psychological variables such as life events and loneliness.
The finding were that NK cell activity was significantly reduced in the second round in the second blood sample, taken during their final examinations, compared with the first sample which was taken one month before their final examinations, NK cell activity was most reduced in participants who also reported high levels of life events and loneliness. Glaser concluded that examination stress reduces immune function, potentially leaving the individual vulnerable to illness infections, also that the immune function is also affected by psychological variables such as the stress of life events and feelings of loneliness.
These long term stressors may make individuals more vulnerable to the added effect of short term stressors such as examinations. Overall this was essentially a correlated study, so a strong conclusion about a cause and effect relationship cannot be drawn, also it was a natural experiment using a natural source of stress and therefore had reasonable ecological validity, but the students may be a special group of generalization should be made with caution.
Glaser also said even short term predictable and relatively benign stressors can increase vulnerability to illness. She included individuals who have stronger close personal relationships are less likely to show adverse immunological consequences when stressed, for example when she followed students through exams she found lonelier students had lower NK cell activity than those were not lonely. In Glaser’s studies she said the most consistent gender differences occurred in response to material conflict, for instance she said the relationship between adverse hormonal and immunological changes, and negative or hostile behaviours, were stronger for women than men.