AROUND the turn of the century, the leading causes of death were diseases such as pneumonia, tuberculosis and flu. These have now been controlled by science and the average person lives into their 70s.
The body gradually weakens over this long life span and, in many cases, diseases of old age develop, for example, silting up of arteries, and the deterioration of the immune system, allowing cancer to develop.
It is now known that the way we live and, in particular the amount of stress we experience, can have a marked effect on these diseases of ageing and the pace at which they develop.
By stress I mean a mental or emotional strain or tension. As will be explained next week in part two of this article, stress is a normal part of our lives. If it is handled properly, it causes no ill effects. However, if it is not, stress can cause ill health.
An extreme example of problems caused by stress can be seen in the effects induced by overwork among the Japanese.
They work harder than Europeans, officially 400 hours a year harder. Unofficially they work even longer than that. In many cases the stress induced by this over work reaches such intense levels that it results in sudden death. I read a report a few years ago that 10,000 Japanese literally work themselves into the grave annually. The syndrome is known in Japan as Karoshi.
The stress syndrome was first recognised in the mid 1920s by a Hungarian physician called Hans Selye. He noticed that patients arriving in hospital suffering from a variety of illnesses shared many symptoms, fatigue, weight loss, and aches and pains in joints.
Selye was at a loss to know why so many different illnesses displayed the same symptoms. He found an explanation several years later when conducting an experiment on rats. He was investigating the effects on the rats of injecting them with a chemical extract which he believed contained a new hormone.
As a control in his experiment he injected other rats with a benign salt solution. After days of being painfully jabbed and prodded, the animals began to develop gastric ulcers, over active adrenal glands and withered thymus glands (signifying a collapsing immune system).
Both the control and the experimental rats developed these symptoms. With a remarkable display of insight, Selye interpreted the behaviour of the rats as a physiological reaction to stress. He went on to generatise that this is the same whether the stress is caused by sharp needles, the sight of a hospital bed or an imminent mortgage repayment when funds are not available.
Evolution has programmed our basic physiological and biochemical mechanisms to automatically react to stress in a certain manner. This is an important protective mechanism.
When we are suddenly confronted witch a situation that is either dangerous or requires immediate physical response, our bodies automatically undergo changes to equip us for immediate fight or flight.
The brain and the pituitary direct the adrenal glands to secrete large amounts of hormones, particularly adrenaline and glucocorticoids, into the blood. The glucocoiticoids immediately mobilise the body's energy reserves (mainly by converting stored carbohydrate into free glucose) and glucose is made available to be used by our muscles for fight or flight.
The glucocorticoids also inhibit many long term building processes: they slow down digestion; they block the release of hormones needed for reproduction; they inhibit growth by reducing the secretion of growth hormone. They also suppress the immune and inflammatory responses which guard against infection and repair injuries. Adrenaline causes arteries to narrow and blood pressure to rise, speeding the flow of glucose rich blood to the muscles.
The hormonally induced changes just described are very important in order to allow us to respond quickly to sudden emergencies. In everyday life the occasional emergency situation will arise, hormone levels will rise the situation will be dealt with and then hormone levels will quickly drop to resting levels again.
But if one frequently perceives events as threatening, adrenaline and glucocorticoids will be very regularly secreted in the "fight or flight" mechanism.
Therefore, the average level of these hormones in the blood will be considerably higher in such an individual than in one who only occasionally perceives events as being very threatening. One side of the action of the glucocorticoids is to exact a "wear and tear" effect on the body by inhibiting various processes as already described.
Under normal circumstances this toll is maintained at an irreducible minimum level. However, under conditions of regular stress, the constant higher level of glucocorticoids in the blood exact an unacceptably high toll of wear and tear.
Higher than normal levels of adrenaline and glucocorticoids in the blood on a chronic basis can lead to one or more of the following problems: the breakdown of energy reserves leads, in the long term, to fatigue and wasting of muscle; chronic inhibition of growth and repair of the skeletal system leads to fragile, decalcified bones; the slowing down of the digestive, immune and reproductive system eventually can result in ulcers, impaired resistance to disease, impotence and infertility; chronically increased levels of glucocorticoids can also injure the brain.
This may not necessarily lead directly to neurological disorders, but the effects of events such as strokes may be more severe under these conditions than they would be otherwise.
In this article I have explained the Physiological basis for how stress can cause ill heath. This is important and interesting information, but to leave the subject there would be to leave matters hanging in mid air. What is really important to know is how to manage stress in everyday life so that it will not become a problem.
The capacity to cope with stress varies from individual to individual. An event that one person might view with alarm, another person might be able to handle with equanimity. How we perceive things is therefore of critical importance.
The way forward for a person who is easily stressed is to learn how to change his/her thinking about the "threats" the world presents. Next week, part two of this article explains how we should handle stress and is written by a clinical psychologist, Dr Breda McLeavey, of Cork University Hospital.