There is growing evidence that stress is a major factor in maintaining health and well-being. Health means more than the absence of illness. In China and in ancient Greece health was thought of as being in balance with nature. The vital task was seen as maintaining equilibrium in the face of extensive demands. The World Health Organization (WHO) definition of health is a state of complete physical, mental and social well being.
It seems increasingly clear that the naive notion that a germ automatically leads to illness is no longer acceptable, although much of the lay public subscribes to the theory. Today we know that the idea of a single external cause, such as a germ, is oversimplified. The presence of the germ does not always cause the illness. The vulnerability of the person or the host animal is a major factor and that vulnerability is influenced by such factors as immunity and stress levels. So the cause of illness is not quite as simple as we once thought.
Stress vs. Distress
Another important distinction that came out of the seminal work of Hans Selye is between stress and distress. Both involve demands on the person to adapt to a challenging event. However, when we appraise the situation as being something we can handle it can be an exhilarating experience. When a person appraises the event as beyond their ability or as exceeding resources the situation is experienced as distress. Another way to look at it is that stress is positive and distress is negative. It is a valuable distinction since many people believe all stress is bad for you. It is not.
The diathesis-stress theory
The diathesis-stress theory of the origin of certain illnesses holds that we are born with certain biological predispositions but that whether or not an illness manifests itself is dependent on the level of stress one experiences and the resources one can use to overcome the stress. For example, although a person may have inherited a genetic deficiency in metabolizing alcohol, whether that person becomes an alcoholic or not also depends on the types and levels of stress they experience. Another person may have inherited a problem with glucose metabolism; however, it is factors such as the level of stress, or a sedentary life style or a combination of the two that result in development of type 2 diabetes. We may be born with certain vulnerabilities; it is stress that tips us into active illness.
Impact of stress on illnesses
Certain ailments have been recognized for some time as being influenced by stress. The most common example is intestinal distress such as indigestion and colitis. Other disorders like migraine, tension headaches, high blood pressure, arthritis and certain skin disorders may also be influenced by stress. In some instances, stress emotions seem to make an ailment worse, while in others stress may be a factor in bringing on illness. Research increasingly supports the hypothesis that stress may have at least some impact on many diseases.
There are several reasons for believing that stress contributes to the development of cardiovascular disease. First, stress emotions increase the level of low-density blood cholesterol and this leads to clogging of the arteries of the heart. Second, stress emotions result in maladaptive coping behaviors such as smoking, drinking and overeating, which can damage the heart and surrounding vessels. Finally, stress emotions result in the release of powerful hormones which result in increases in heart rate and blood pressure. One of these stress emotions is anger, and anger expressed in the form of hostility is known to increase the risk of cardiovascular disease.
Several hypotheses are being explored in the role of emotions in cancer. Again stress emotions may play an indirect role leading the person to smoke or drink excessively. More direct influence is attributed to a tendency to suppress or deny emotions. There is some evidence that those who suppress emotions are more susceptible to cancer. Again the mediating factor is hormonal activity.
At the 2002 meeting of the American Psychological 