Pressure leads to chemical changes, then breakdown

Comment: Dr Fred Kavalier

Stress, however it is defined, has profound effects on both mental and physical health.

Stress, however it is defined, has profound effects on both mental and physical health.

Although human beings have evolved to be capable of withstanding the stresses of life, there is evidence that too much stress can contribute to both physical and mental illness.

The stress response is often described as a "fight or flight" reaction. Anything that threatens a person's well-being sets off neurological and chemical changes in the body that prepare us either to escape from danger, or to fight for survival.

Within seconds of encountering a stressful situation, the stress reaction increases the body's metabolism. The heart begins to beat faster and the blood pressure goes up. The rate of breathing increases and more oxygen is taken up by the lungs. Within the blood vessels, the ability of the blood to form clots quickens to lessen the amount of blood that is lost in the event of physical injury.

All of these physiological reactions were essential for the survival of our evolutionary predecessors. But the same reactions can also do harm if they become part of everyday life.

There is increasing evidence that unrelieved stress can contribute to a large number of illnesses, both physical and mental.

The evidence that stress contributes to mental illness is particularly strong. Stress at home, stress in personal relationships and stress at work can all be implicated in the onset of depression and anxiety.

It is common for an episode of depression to occur after a period of stress, and often the depression will be more difficult to treat if the underlying stress is not relieved.

On the physical side, there are many illnesses that seem to be stress-related.

High on the list are gastrointestinal conditions such as irritable bowel syndrome. But other problems, such as low back pain, skin rashes and migraine, are frequently linked to stress.

There is a widespread belief that stress is an important factor in high blood pressure, coronary heart disease and heart attacks.

The so-called "Type A" personality, which is typified by the workaholic who is over-conscientious and never able to relax, may be more likely to suffer from raised blood pressure and heart disease.

But although stress may be a factor in the onset of these physical illnesses, it has never been proved to be as important as other risk factors such as smoking and lack of exercise.

Perhaps the most controversial question of all is whether being "stressed out" makes it more likely that you will eventually succumb to cancer. Although there has been a great deal of research, there is certainly no conclusive evidence that stress causes any kind of cancer.

* Dr Fred Kavalier is a GP in north London.