LONG TERM PHYSIOLOGICAL EFFECTS OF STRESS
When someone suffers from chronic stress or the ongoing trauma from a negative life changing event, it is very physically exhausting. If you imagine your body continuously in a fight or flight response state then it should become obvious that this will quickly drain your physical and emotional resources. It takes so much energy that our bodies simply cannot maintain this level of alertness indefinitely.
Over the years, a number of researchers have examined the relationship between long-term stress and our body's ability to fend off disease or illnesses. Of interest here is a study by Selye (1956) in which the author made reference to a General Adaptation Syndrome (GAS).
Following studies with animals, Selye proposed that there are several phases to our adaptation to long-term stress.
Alarm Phase
Firstly, we experience an alarm phase which represents the typical fight or flight response and involves activation of the sympathetic division of the autonomic nervous system. When this occurs adrenaline is released to prepare the body and muscles for action.
Resistance Phase
Under normal circumstances the release of adrenalin would cease as the cause of the stress dissipates and we would use less energy maintaining a state of arousal, but if the stress continues then we experience a resistance phase. During this phase the body tries to go back to normal but it must continue to deal with high level of adrenalin and our physiological alertness. If we are exposed to an additional new stressor during this phase then we produce much less resistance to it because we don't have the energy to combat it.
Exhaustion Phase
Finally, our energy reserves become so depleted that exhaustion ensues. Although our physiological arousal levels return to normal resting levels there is still a high level of adrenalin in the bloodstream. When someone reaches this phase not only are they less resistant to further stressors but they also have a heightened response to them because of the higher levels of adrenalin in their blood. They might display an abnormally strong stress reaction to what most would regard as a minor stressor.
Following on from this work, many other researchers have investigated the link between long-term stress and physical illness or disease. For instance, Solomon (1963) observed that individuals experiencing the general adaptation syndrome not only had a raised likelihood of developing a physical illness, but were more likely to experience feelings of physical weakness and general fatigue.
Some long term health risks associated with ongoing stress include:
- Heart attack
- Heart disease
- Strokes
- Cancer
- Ulcers
- Increased susceptibility to infection
- Diabetes
- Infertility
- Obesity - due to comfort eating
Occasionally we hear people use the pithy saying "they died of a broken heart'. However, there is some logic behind this seemingly ridiculous saying since some people do indeed die very quickly following the death of their partner. A 2012 study by Dr Mittleman et al at Harvard University found that people are 21 times more likely to have a heart attack within a day of becoming bereaved. The risk drops to six times higher than normal in the days following the death, eventually declining in the following month to normal levels.
We shall now review some well documented associations between stress and physiological conditions.
Gastric Ulcers
Stomach ulcers are one of the more commonly cited physiological responses to stress. At one time they were largely considered to be psychosomatic in origin - that is, caused by stress and other psychological disturbances. Nowadays, it is accepted that gastric ulcers are caused by a particular bacteria in the gut but that the effect of these bacteria is exacerbated by stress. The reasoning is that most people have the bacteria (Helicobacter pylori) present in their guts but do not develop ulcers. Furthermore, whilst ulcers usually improve following treatment with antibiotics, they also improve following treatment to reduce stress.
It seems that the immune system may be compromised under stress and so the stomach wall becomes more susceptible to infection from these bacteria.
Immune System
Many studies have found a positive correlation between stressors and diminished immune system function. In laboratory animals stressors such as loud noises, overcrowding and, somewhat disturbingly, electric shocks have been manipulated to incur stress and demonstrate a depressed immune system through increased susceptibility to infectious diseases. In humans, stressors which have been found to positively correlate with depressed immune system function include divorce, taking exams, caring for a terminally ill relative and bereavement.
For instance, Glaser et al. (1987) found that medical students were more likely to report having coughs or colds during exam periods than at other times. In a study by Irwin et al. (1988) bereaved women who had lost their husbands had significantly lower levels of natural killer cells in their blood during the first six months after their loss.
Given that stress causes many physiological changes in bodily systems it is not possible to specify exactly how it affects the immune system, only that there is an association. It should also be noted that in much the same way as stress can influence physiological systems in the body infections themselves can affect psychological functioning.
Coronary Heart Disease
Coronary heart disease is the biggest killer of people in Western countries. It is a disorder of the blood vessels which carry blood to the heart which are usually affected by atherosclerosis. A number of studies using those with Type A and Type B personalities (which we shall come to in the next chapter) have implicated type A personality patterns in increased susceptibility to coronary heart disease.
Those with Type A personalities are more competitive and hostile, and have higher levels of arousal of the sympathetic division of the autonomic nervous system.
