Stress ‡ an emotion, a state of psychological tension and physiological arousal produced by a stressor which makes the individual ready to respond, It is an adaptive response because it enables the individual to cope. It becomes maladaptive if the stressor persists Stressor ‡ a physiological or psychological stimulus that threatens an individual’s well being. It could lead to a stress response. THE BODY’S RESPONSE TO STRESS
The General Adaptation Syndrome (GAS) – model outlined by Seyle (1936) Observed that all animals produce the same sequence of responses to all stressors: cold, pain, and physical trauma. This response is adaptive because it enables the individual to cope under stress. 1. ALARM ‡ Prepares you to respond to environmental demands. The HPA system is activated: the sympathetic branch of the ANS is aroused and ACTH and adrenal hormones are released in readiness for fight or flight. 2. RESISTENCE ‡ If the stressor persists, the body adapts by returning to a normal level of functioning while coping with the stressor. Hormone production is maintained but at lower levels. 3. EXHAUSTION ‡ Eventually the body’s resources are depleted. Adrenal glands are not functioning, leading to low blood sugars and various psychosomatic disorders such as ulcers. Evaluation of GAS syndrome
STRENGTHS ¸ Seyle observed stress reactions in rats and confirmed this is studies of hospital patients with various injuries and illnesses. WEAKNESSES v Ignores the role of emotional and cognitive factors – possibly because of use of non-human animals. ‡ ‡ Lazarus showed that people experienced stress during a film depending on what they’d been told beforehand – cognitive appraisal affected the stress experienced. v Seyle thought that GAS was a non-specific response to any stressor but different stimuli lead to different responses. Also individual differences and situational differences.
SAM system – acute stress ‡ Automatic Nervous System
1. Arousal of the sympathetic branch of the ANS
2. Adrenal medulla releases adrenaline
3. Adrenaline causes sweating etc
HPA axis – chronic stress ‡ Hypothalamic Pituitary-Adrenal axis 1. The hypothalamus stimulates the pituitary
2. Secretes a hormone called ACTH
3. Stimulates adrenal glands to produce a hormone called cortisol – maintains blood sugar levels for energy. How adrenaline affects the body:
¸ Increased heart rate ¸ Sweating ¸ Increased blood pressure
THE EFFECTS OF STRESS ON PHYSICAL ILLNESSES
CARDIOVASCULAR DISORDERS These are any disorders of the heart (e.g. coronary heart disease) and circulatory system (e.g. hypertension – high blood pressure.) Coronary heart disease is caused by the narrowing of the coronary arteries (atherosclerosis.) This is likely to produce angina (chest pain) or a heart attack. Lifestyle choices also affect cardiovascular disorders - smoking, drinking (Cohen and Williamson) Stress leading to physical illness DIRECTLY ‡ GAS model Stress leading to physical illness INDIRECTLY ‡ people are more likely to smoke or drink. How stress DIRECTLY causes cardiovascular problems: • Increased heart rate ‡ wears away the lining of the blood vessels • Increased blood pressure ‡ causes damage to the pipes • Increased glucose levels ‡ leading to clumps blocking the blood vessels (atherosclerosis.) KEY STUDY 1 Kranz 1991 – effects of stress on cardiovascular disorders.
KEY STUDY 1 Friedman and Rosenman (1959) – Type A and Heart Disease Other research ‡ Williams (2000). ACUTE STRESS STUDY Aimed to see whether anger was linked to heart disease. 13,000 people completed a 10-question anger scale. None of participants suffered from heart disease when study was done. 6 years later, participant’s health was checked: 256 had had heart attacks. Those who scored highest on scale were 2.69x more likely to have a heart attack. Russek and Zohman (1958) CHRONIC STRESS STUDY Looked at heart disease in medical professions High Stress = GPs Low Stress =...