Stress is a relatively new notion that everybody talks about, yet few understand. The dictionary defines stress as "pressure, force, strain; a state of physical or mental tension inducing it, or affecting something.' This definition, while obviously correct, is not very helpful in understanding the concept of stress. On the other hand, it is important to comprehend the notion, because all of us are continuously exposed to stress. Stress occurs in many forms. The four major categories which concern us are:Types of Stress Chemical Stress Emotional Stress Physical Trauma Infectious
Each of these stress forms can originate from multiple sources. Most of these have appeared as primary threats in our environment as recently as this century. For example, chemical stress can come from pesticides, insecticides, polluted air and water, heavy metals such as mercury or lead, asbestos and worst of all radioactive waste. Even jet travel, a welcome commonplace today but unheard of a mere half century ago, exposes passengers to an unhealthy high level of ozone and random cosmic radiation's. In the light of such widespread physiological insult, it is a true miracle that any if us manage to stay healthy at all.
One of the primary reasons why stress is so important to understand, is because it is intricately linked to the functioning of our immune systems. How many of us have gotten a cold when our defenses were impaired by excessive stress? This is another angle from which to view to view the recent rash of immune disorders unleashed in our culture. Could these problems be partly caused by an overwhelmed immune system? It should be obvious that this is quite possible, and the more we consider the high levels of stress that most of us are exposed to daily, the more relevant the idea become. In other words, understanding and compensating for the stress in our lives will help our immune systems and enhance our ability to stay well.
This is not to imply that all stress is harmful. Exercise, for example, is a form of stress on the body which is quite healthy. Yet if we over-exert ourselves during exercise, we can damage the body and create problems. As we have already mentioned, many unavoidable stress factors, such as pollution, and others that cause damage to the body, stem from today's world of technological progress. In many cases the physical result brought on by several different forms of stress is the same. The unnecessary, but avoidable results are cellular damage caused by over-reactive molecules called "Free Radicals."
Due to their over-reactive nature, free radicals can be extremely toxic and are a direct consequence of the primary stress factors that adversely affect the immune system and threaten our health. However, this is not to imply that free radicals are always harmful or dangerous. Minute amounts of free radicals are essential for many important functions of the immune system and other vital cellular activities. For example, the immune system will actually generate free radicals to use in the process of removing a virus or bacteria. Only when high concentrations of free radicals are present, or when the levels of free radicals overwhelm the body's ability to remove them, does the threat to our health occur.
Maintaining the balance between free radical activity and antioxidant enzyme supply is one of the important functions of the body (Fig. 1)