When threatened or stressed, our bodies mount a chemical response, and while this response affects our emotions and outlook, it begins and ends in the body.

University of California, Berkeley Wellness Letter

Stress is a word on everybody's lips. But how any two people define it can differ dramatically. Scientists increasingly look at stress as an important factor in the origin of illness.

According to a recent study in the American Journal of Public Health, civil servants in very stressful jobs are more prone to high blood pressure and heart disease. A divorce or a death in the family can weaken the immune system. Soldiers stressed by service in a war zone may suffer long-term physical effects, as has been documented in all major wars, from the Civil War to the Gulf War.

But for most people, unfortunately, "stress-related" translates as "all in the mind" or a sign of weakness. Nothing could be further from the truth. To say that an illness is stress-related is not a fancy new way to blame the victim. It is a recognition that severe, prolonged physical and emotional stress can have adverse physical effects.

Not Imaginary
When threatened or stressed, our bodies mount a chemical response, and while this response affects our emotions and outlook (and is, in that sense, "in our heads"), it begins and ends in the body. Stress mechanisms, it must be remembered, play a dual role. The rise in anxiety and hormone levels that accompanies stress is essential and protective.

All organisms have to experience stress and adjust to it. Being born is stressful. Being alive is stressful. Without our stress hormones we would be unable to react effectively, or to deal with hunger, crowding, danger, infection, extremes of temperature or the challenges of growing up. We would be unable to get out of bed in the morning. But when and why do the physical effects of stress stop protecting us and begin to damage us? What can we do to offset these effects?

Scientists are beginning to unravel the physiological pathways between the brain and body. Through these pathways, stress can have measurable effects on such systems as the immune, cardiovascular and endocrine systems, as well as the brain itself.

In an important article in the New England Journal of Medicine in January, Dr. Bruce McEwen of Rockefeller University in New York goes a long way toward charting the interplay of physical and emotional stress. He points out that our "allostatic systems" respond specifically to protect the body.
Allostatic systems are the parts of the nervous system that control heartbeat, blood pressure and similar functions; the hypothalamus, pituitary and adrenal glands (which work together to produce a hormonal response); and the cardiovascular, metabolic and immune systems.

We adapt to usual, everyday stresses. However, when stressful events persist or recur frequently, this can be expressed in a variety of physical illness symptoms. The physical reaction to stress may not go away. Enough stress over a long period causes us to lose the ability to "calm down" physiologically.
How Damage is Done

Dr. McEwen defines years of unresolved stress in terms of "allostatic load," which is "the wear and tear that results from chronic overactivity or underactivity of allostatic systems."

Real life may present situations you can find no reasonable or constructive way to react to -- an unexpected death, the wear-and-tear of a job you hate, a bad marriage, experiences in war, social rejection, loneliness and a dozen other things you can't control and can't seem to get past. Or perhaps you're just depressed all the time. And bad things seem to last forever. Maybe you stay in a chronic state of stress, with your blood pressure and adrenal hormone levels elevated. Some people may lose the capacity to react to stress.
Chronic stress -- carrying around a heavy allostatic load, as it were -- can damage the immune system and other systems as well. It is known to be linked to the development of insulin resistance (a risk factor for diabetes), as well as hypertension and coronary heart disease, osteoporosis and other disorders. It may even promote cancer. Our knowledge is in an early stage.

Dr. McEwen believes that the two most important causes of heavy allostatic load are a sense of isolation (lack of social support) and a lack of control (being subjected to deeply stressful situations, as in battle or chronic job stresses you can do nothing about).

Toting Your Allostatic Load
But what makes up our individual allostatic load is far from simple. Genetics play a role, as does what happens to us in life--trauma or lack of it, good or bad fortune, caring or neglectful parents, failure or success in our goals. How we live, what we eat, whether we smoke or not, whether we drink alcohol excessively, whether we are active or sedentary--all are part of the package.
Where we stand economically and educa-tionally is a factor in the stress loads we carry, as is the treatment accorded us by our societies--for example, if we experience discrimination on one basis or another, or if our abilities are discounted.
Early childhood experiences, according to Dr. McEwen, are key in setting the level of responsiveness of physical stress mechanisms and the physical and mental ability to manage our allostatic load. That is, a child who learns coping skills early, is given the chance to solve problems successfully and is not subjected to isolation or other threatening situations will have better chances of growing into a healthy, productive adult who can handle stress. Common sense has long taught that this is so, and now we are beginning to see why, in physical and hormonal terms.
Of course, one of the most important variables is how each person responds to stress. Some people meet stressful situations of all kinds and manage to find ways of solving problems. Some people have a harder time.

Increasingly, says Dr. McEwen, consideration of allostatic load should be a factor that physicians consider when diagnosing and treating illness. Doctors ought to help patients reduce their allostatic stress level by helping them learn coping skills and change unhealthy habits. Improving work environments and the circumstances in which children are brought up--at home, in day-care, and in schools--can also help reduce stress loads in years to come.

What's the Payoff for You?
It is not possible to alter what happened to you as a child, nor can you simply drop your allostatic load by the side of the road like a suitcase. But if you live in isolation or without essential social support, you might try to reach out by, say, joining a volunteer or civic or church group, or perhaps seeking counseling. If you smoke--a sure sign of unhealthy coping--try to quit.

Eating a healthy diet is another way to confirm that you care about your own well-being. Regular physical exercise fits into the picture, too. Those who walk vigorously or play sports frequently extol the benefits of exercise for dealing with stress.

Last words: There is still a lot to learn about the long-term effects of stress, its role in damaging the immune system and its importance as a cause of aging and chronic disease. But the review by Dr. McEwen shows that research on stress has begun to pay off in concrete ways and can guide us toward building a healthier world. The hard lines between mental, physical and emotional health seem to be vanishing.