Physical, mental, or chemical ... What is stress?

Press, 24 July 1986, Page 21

Physical, mental, or chemical ... What is stress?

You often hear that someone is “under stress.” What is stress?

One medical dictionary defines it as “anything which disturbs the natural balance of the body and its tissues.”

Dr Hans Selye is probably the best-known researcher on the physiological effects of stress and he says that stress is essentially the rate of wear and tear on the body.

In general usage, the term has most often come to be applied to mental stress, but physical and chemical stresses can also markedly affect health.

The health of the whole body depends on the health of individual cells within the tissues and an integrated functioning of all cells.

The great nineteenth century ’physiologist Claude Bernard recognised that the body needs a constant internal environment for its cells to function at their best. The health of individual cells depends on a constant supply of oxygen and nutrients to the fluid which surrounds them. Lack of necessary nutrients, or a build-up of waste products in the fluid outside a cell, can be stressful to that cell.

During strenuous exercise the tissue fluid is not able to supply sufficient oxygen to the muscle cells to meet their needs. This results in the production of lactic acid and a buildup of carbon dioxide in the fluid around the cells. The muscle cells are stressed.

Repeated stress to any

By

Lois Tucker

tissues or organs tends to cause them to enlarge to cope with the extra demands which are being made upon them. People involved in body-building programmes know that in order to develop a particular muscle group they must regularly exert those muscles.

Stressing muscles, including heart muscle, is said to be the key to gaining fitness, but there is some debate about how much stress is desirable in the pursuit of fitness.

Just where is the dividing line between exertion and over-exertion? Prolonged and repeated physical stress can lead to accelerated degeneration.

To achieve cardiovascular improvements by regular aerobic exercise, the heart and muscles need- to be stressed. However, moderation in exercise programmes, as well as in other aspects of life style, seems to me to be the best way to achieve a long and healthy life. Pushing yourself physically to the point of pain

results in increased “wear and tear.”

Some athletes regularly push themselves to pain levels because of the “high” they achieve when the brain secretes endorphins in response to the pain. Endorphins are mor-phine-like chemicals which are the body’s own opiates. The body needs activities which will exercise many muscles, not just repetitive stress on a few muscles. Athletes, as well as typists, are aware of the injury which can result from overstress. We should vary our activities and exercise as much as possible to prevent repetitive stress injuries. Physiological stresses are not brought about only through muscular exertion. Physical factors (such as extremes of temperature), excesses or deficiencies in diet, situations at work and interactions within the family can all be stressful.

We can also needlessly bring stress upon ourselves, for instance by not allowing enough time to get comfortably to an appointment. Some stresses produce only localised effects, but severe stresses can bring about a more generalised reaction, particularly if they are prolonged. Dr Selye studied in detail how the body adapts to such stress. He decided that the body adapts in a very similar way to a wide range of stresses. He identifies the main response as affecting the adrenal glands, the immune system and the gut.

He considers that the response to stress (goes)

phases, which he calls the alarm reaction, the stage of resistance, and the stage of exhaustion. During the alarm stage, the adrenal glands release large amounts of hormones from their outer (cortex) cells. During the stage of resistance they respond by enlarging and producing more hormones.

While the adrenal glands enlarge, tissues of the immune system decrease in size and the gut may show changes, such as developing ulcers. When the stage of exhaustion is reached, symptoms of degenerative disease may become evident.

Our bodies do adapt to a certain level of stress, but by decreasing our stress load we can reduce the rate of wear and tear on the body.

We have to learn to recognise which stresses we are creating ourselves — not an easy task! We can reduce these.

But we may need professional advice to help us adapt to severe stresses which are not of our own making.