Every day, over one million people miss work due to stress or a stress-related illness. The hidden effects of stress are costing American businesses at least $150 billion each year in lost productivity, absenteeism, and health-care expenses.

Nine out of ten Americans complain that they experience high levels of stress at least once or twice every week; one in four say they are stressed-out every day. An estimated 75 percent of all visits to physicians are made by people who have stress-related problems.

Most of us feel that stress has simply become an unavoidable consequence of modern life. The first step to controlling stress is to recognize that while we cannot always control what is causing it, we can learn to control how we respond. This is complicated by the fact that stress is one of those words that most people can tell you what they think it means, but no one can really define.

Stress, according to medical references, is defined as "any emotional, physical, social, economic, or other factor that requires a response or change..." A stressor, on the other hand is "anything that causes wear and tear on the body's mental or physical resources."

In Margaret's case, her body was responding loud and clear to her excessive anger at being delayed at a traffic light. She was experiencing the classic "flight or fight" response that is as old as prehistoric time.

The adrenal glands increase production of epinephrine or adrenaline and send it into the blood stream. This stimulates the liver to release some stored carbohydrates for extra energy. The heartbeat quickens in anticipation, muscles tense and the blood pressure increases to prepare the body for extraordinary physical exertion. If none occurs, this frustrated readiness may cause headache, upset stomach, and a host of other physical and mental symptoms.

This response might have been just what cave dwellers may have needed to take care of an aggressive saber-toothed tiger; but, in an age where predators wear pin-stripped suits, too much of a good thing can translate to potentially life-threatening physical changes.

Bodies exposed to constant, unresolved stress never have a chance to recover. The symptoms get worse: backaches, gastrointestinal upsets, depression, arthritis, skin disorders, weight problems, PMS, and -- all too often -- drug and alcohol abuse.

Researchers have pretty conclusively linked stress to specific illnesses. It may not, by itself, cause illness, but it contributes to circumstances in which disease may take hold and flourish. Stress has been shown to weaken and disturb the body's defense mechanisms.

Not everyone responds to stress in the same way. What produces anxiety in one person -- speaking in public, an approaching deadline -- may be just what another person thrives on and may actually need to excel.

Every one deals with life's stressors in different ways. This may be due, in part, to biological factors or even a person's genes. People who are able to deal well with stressful situations, according to some recent research, tend to control their lives and look for viable solutions to their problems. They decide on meaningful goals, they don't rely on nicotine or caffeine to get by, and they tend to relax at least 15 minutes each day. They also exercise regularly and are actively involved with others.

The first step to learning to deal with stress is to distinguish between things you can do something about and those things you can't change. Experts suggest making a list of the stressors in your life and then separating them into these two categories. This may sound like a simple exercise, but most people don't think things through under the influence of stress. Once you have identified those things you can do something about, it is much easier to develop a realistic action plan and to tackle the challenge of solving the problem.

Recognize that there will always be stressors in your life that can't be avoided. When you can't change them, change your outlook instead.

Once you have determined that stress is impacting your health and happiness, it is up to you to decide what to do about it. Depending upon the seriousness of that impact, several options are available.

You may be able to tackle the problem yourself with some positive thinking and planning, or you may need the training available through a stress management program. If this is the route you decide upon, check the credentials of the person or organization offering the program. Unfortunately, with stress reduction becoming such a hot topic, there are some self-styled "experts" offering training who are not qualified or licensed, but are merely cashing in on a fad.

For many people, biofeedback provides an efficient way to monitor and control what we have always thought of as the body's involuntary functions. This high-tech equipment has sensors that are attached to various parts of the body -- the fingers, hands, arms, shoulders, and face -- that measure physiological reactions such as temperature, heartbeat, and muscle tension, and produce lights and sounds in response to changes. The subject learns to use the signals as a guide to control the body's response, by using focused thoughts.

Before committing to a biofeedback program, however, check the practitioner's credentials and training. Look for a background in counseling or health physiology and be wary of anyone who promises a quick fix. If in doubt, ask your doctor for a recommendation or referral