S-Cool Revision Summary
S-Cool Revision Summary
What is 'stress'?
Stress is a type of alarm reaction, involving heightened mental and bodily states - it is both a psychological and a physiological response to the environment. Your brain produces a stress reaction when you are in a situation that is physically or mentally demanding.
Your body's reaction to stress
Your brain is on the look out for anything that threatens to upset its equilibrium - if there are serious 'stressors' around, it triggers off an 'alarm reaction'. The alarm reaction prepares your body for action - sometimes known simply as the 'fight or flight reaction'. Stress hormones and the action of the sympathetic nervous system prepare your body for vigorous muscular activity as follows:
Breathing rate increases
Blood flow to skeletal muscles increases
Heart rate increases
Blood sugar levels increase
Blood pressure in arteries increases
Intestinal muscles relax
So, what if you are not in a situation in which it's OK to suddenly get up and run a four-minute mile round the block?
Well, that's when various unpleasant effects may set in, such as throbbing headaches, irritability, tense neck and shoulders, dried up mouth and butterflies in the stomach. Sound familiar? Most people experience this sort of stress sometimes.
The flow diagram below shows what goes on in the body when the brain detects a potentially harmful 'stressor':
All the stress hormones circulating in the bloodstream and the neural effects of the sympathetic nervous system combine to create the 'fight-or-flight' response.
The hypothalamus plays a key role in the control of the endocrine system. There is a complex feedback system between the hypothalamus, sympathetic nervous system, the pituitary gland and the secretions of the adrenal glands.
The adrenal glands are found on top of your kidneys - they secrete epinephrine (otherwise known as adrenaline) and other 'stress hormones'. The activity of your adrenal glands is crucial to your mood, energy levels and ability to cope with stress.
In extreme cases of stress your adrenal glands may become enlarged, the spleen and thymus glands may shrink and deep bleeding stomach ulcers may occur. (Not very nice!)
Selye pioneered stress research in the 1950s - he came up with the idea of the general adaptation syndrome. This is a collection of symptoms shown by the body in response to any stress - physical illness such as infection or injury, or stress due to psychological factors. The key thing is that it is 'general' - a non-specific response to any illness.
Here are the three main phases of the 'general adaptation syndrome'.
Shock phase - response to stressor. Hypothalamus, sympathetic nervous system (heart rate and blood pressure increases), pituatory gland and hormones (e.g. adrenaline and corticosteroids) activated.
High level of arousal maintained. Prolonged release of corticosteroids reduces the efficiency of the immune system. High blood sugar levels are maintained in this phase.
Psychosomatic illnesses develop. Body's reserves of energy run down. Enlarged adrenal glands, muscle fatigue, warn out tissues, kidney damage, ulcers, heart damage.
The idea of the 'general adaptation syndrome' was drawn from very early research on stress.
It has been criticised because it was based on work with animals and tells us nothing about psychological or emotional factors.
Physiologists have also argued that there may well be different physiological responses to different stressors and not just one 'general' syndrome.
In other words, Selye's model to explain stress is too simple - in reality, the process is more complex.
Stress and illness
Research has shown strong links between prolonged stress and many disorders, mentally and physically. The immune system is easily affected by stress...
Colds and flu
Eczema and other skin disorders
Post-traumatic stress disorder
You should be aware that stress might lead to behaviour, such as smoking or overeating, which increases the risk of serious illness - so the link with the original source of stress is indirect.
The incidence of cancer has been correlated with high stress levels.
Jacobs and Charles (1980) found that cancer patients - for example, child cancer patients, often suffered high levels of stress before the diagnosis of their illness.
Tache et al (1979) found the incidence of cancer to be higher in those with a poor 'social support network' such as the widowed, divorced or separated.
It is difficult to rule out that undetected, developing cancer might cause stress, rather than stress due to external factors leading to cancer.
Stress and heart disease
The 'risk factors' linked with cardiovascular disease include diet, smoking, obesity, lack of exercise (or over-exercise) and stress. Indeed, stress may well be a cause of other behavioural factors.
Men are more susceptible to heart disease than women, even when diets are matched. Could it be that men have more stressful lives than women such as more job-related stress?
For example, it was found that among 40 male tax accountants, blood cholesterol and clotting speeds were at dangerous levels in April (The end of the financial year!)
Perhaps women in this type of work would also show similar signs of stress. There have not been many studies into women's stress levels, but it is worth noting that the incidence of stress-related behaviour such as smoking is increasingly amongst women.
Here's how stress might lead to heart disease: Stress-related behaviour such as smoking or eating lots of fatty foods will speed up the hardening of the blood vessels stage...
Resting - Stress - Pulse increases - Increased blood flow - Blood vessels 'harden' and wear out - Heart strain.
Causes of Stress
So, what causes the stress that can be so bad for you?
Events in the environment and life changes
Perception of situation - degree of control
Some people may have a nervous system that goes into a stress reaction more readily than others. This could be due to individual differences in genetics and brain chemistry.
To try to understand stress better, we need to consider the psychological factors involved - emotional and cognitive (thinking) factors. Research has suggested that major stressors in our lives are life changes - for example, moving house, marriage or relationship breakdown. Work-related factors, including unemployment and boredom, are also common causes of stress. Differences in personality may also play a part.
A stress reaction is a response to a perceived threat. Different people perceive things in different ways, so a situation that one person finds very stressful might not be to someone else.
Life events and stress
In 1967, Holmes and Rahe came up with the idea of a 'social readjustment rating scale' (or SRRS for short). This was an attempt to quantify life change - any change in your life that might cause stress. Scores are calculated for a person's experiences over the past year. Studies using the scale have found that high life change scores (300+) are related to relatively high frequency of illness, accidents and athletic injuries.
You might be surprised to see Christmas and holidays in there, but they can really be seriously stressful for many people.
Other research in the 1990's showed a correlation between high levels of negative life events with increased vulnerability to colds.
The trouble with this 'social readjustment rating scale' is that it does not account for the fact that some people will find the same sort of event less stressful than others - for example, divorce could be perceived as a relief or a disaster. We cannot give reliable predictions about risks of stress-related illness based on this scale.
Lazarus and colleagues in the 1980s came up with a different stress measurement scale called the 'hassles and uplifts scale'. They claimed that, rather than major life changes, it is day-to-day hassles or small uplifts that determine our overall levels of stress.
Personality and stress
In the 1970s, Friedman and Rosenman carried out a nine-year study of 1000 people to try to find out if personality type affected stress levels.
They came up with the idea of the 'Type A' personality - illustrated below:
The typical 'type A' person is competitive, time-conscious, 'workaholic' and easily frustrated with others. Researchers have suggested that this sort of person would be likely to show more risky behaviour such as smoking, poor diet and so on.
257 men in their study died from heart attacks - 70% of those who died had been judged as having 'type A' personalities.
Critics have argued that it is very difficult to decide if someone has a 'type A' personality or not.
They also say that the connection between personality and heart disease is weak, maintaining that negative emotions such as anger and frustration are more linked to stress-related illness than 'workaholic' lifestyles. These emotions may not be fixed aspects of someone's personality.
In the late 1970's, Kobasa came up with a theory of why some people suffer stress more easily than others, suggesting that some people are 'hardy personality types'.
These people have a sense of personal control over their lives, a sense of purpose and they view life events as challenges rather than stresses. Such people report less stress-related illness.
Stress and control of situations
Other research suggests that 'type A' people are not more vulnerable to stress than others, so other factors must play a part, for example:
Does being in control mean more stress or less?
Brady carried out a notorious experiment in the 1950s called 'the executive monkey experiment' to see how 'executive stress' was related to control of a situation. Stress was measured by the amount of stomach ulcers suffered by the monkeys when placed in conditions in which they were given repeated electric shocks at regular intervals. He found that 'executive monkeys', who had the power to turn off the electric shocks, developed greater ulceration than 'passive monkeys' who were dependent on their 'executive' partners to stop the shocks for them.
Weiss, however, repeated this study with rats using a warning bell to let them know when a shock was about to arrive - giving them an extra level of control - this was found to reduce stress-related symptoms.
Think a bit - what would you conclude from these 'executive stress' experiments?
In the 1970s, Seligman carried out another control-related study and came up with the idea of 'learned helplessness'. Seligman found that when animals had experienced inescapable electric shocks, they did not escape later even when they were given the chance to.
This phenomenon also occurs in humans in response to loud noise. Seligman's work suggested that if life seems uncontrollable, it could lead to symptoms of depression - and depression is often stress-related.
Coping with Stress
Remember: Stress is a normal part of life - it is only a problem when it causes long-term disruption or illness. Normal stress levels can energise and motivate us, directing our behaviour in useful ways. However, in most modern lifestyles, the pressures on people are immense and most people find themselves having to find ways of coping with stressful situations in their everyday lives.
Psysiological arousal system
Perception of situation
The two major components of stress shown in the diagram above, suggest two ways to reduce stress: a biological approach or a psychological approach.
A biological approach might involve drugs or biofeedback, for example.
A psychological approach involves psychotherapy to change cognitive and emotional responses to situations.
It has been found that women tend to use more emotional strategies - changing the way they think about a situation - to try to cope with stress, while men tend to focus more on changing the situation they see as a problem.
Coping with stress can be difficult. It takes time and effort to find new strategies and it can be very hard to overcome the effects of past experience - but a wide range of successful therapies for the treatment of stress is now open to people.
On top of this, the problems of being overloaded at work and stress-related illnesses are now far better understood.
Coping with stress - biological approaches
These methods of dealing with stress focus on ways to minimize and control the body's alarm reactions by direct intervention in the body's chemistry.
These methods are appropriate for people in acute stress states or those who need rapid treatment because they may be vulnerable to heart attack, stroke or blood pressure problems.
Drug treatments may include the use of anti-anxiety drugs, such as benzodiazepines (BZs). Benzodiazepines are also known as 'tranquillizers'; examples are Valium, Librium and Mogadon. These drugs can reduce general arousal and anxiety levels and also help to treat insomnia. There is a danger that people may develop dependence on these drugs.
Other drugs used to treat symptoms of stress include beta-blockers. These can reduce levels of physiological arousal, heart rate and blood pressure.
Another biological approach is biofeedback. The person holds a monitor to measure pulse and blood pressure - they then practice meditation and relaxation techniques to reduce their level of arousal. The results are fed back to them by computer so that they can see how well they are doing. In this way, a person can learn to control their level of physiological arousal, reducing the effects of stress.
Coping with stress - psychological approaches
The simplest psychological approaches to reducing the symptoms of stress are relaxation and meditation techniques.
Progressive muscle relaxation can reduce physical tension and meditation can reduce anxieties. The effects of these techniques tend to be pretty short-lived though, so to be effective they need to become a regular part of a person's lifestyle.
Other psychological approaches - cognitive-behavioural approaches - focus on training a person in new ways of thinking and behaving.
In the 1980s, Meichenbaum came up with the idea of 'stress inoculation training' (SIT). The difference with this approach is that it is meant to be a preventative measure to reduce levels of stress in the first place.
The approaches outlined above aim to reduce stress by reducing the gap between the demands placed on a person and their perception of their ability to cope. By closing that gap, a person's confidence increases and the stress they feel is reduced. With the cognitive-behavioural approach to dealing with stress, the therapist helps the person to be objective about the sources of stress and to develop new ways of dealing with stressful situations. Psychological approaches have also been applied in 'anger management' courses since anger has been found to increase vulnerability to heart disease. These courses challenge a person's views of themselves and others.