Chronic Stress Accelerates the Aging Process

Defining Stress

Stress can be defined as a physiological reaction to a threat. The greater the threat – the greater the level of stress. A threat is a real or perceived action against our person. Threats may include the anticipated possibility of death or injury but may also include challenges to our self-esteem, social standing or relationships to others or a threat may simply be a potential or real disruption of our established routines. What is stressful to one person may not be to another. For example, bumper-to-bumper traffic might be stressful to the woman executive who is late for an important meeting but to the delivery man who has no deadline and is being paid by the hour, it may be a welcome respite to relax and listen to the radio.

Stress produces real physical changes. In some unknown way the fears in our mind, both conscious and unconscious, cause the hypothalamus and pituitary glands, deep in our brain, to initiate a cascade of hormones and immune system proteins that temporarily alter our physical body. This is a normal physiological response inherent to the human body when a threat is perceived – real or not. It is often called the "fight-or-flight response" or the "stress response". The purpose is to give us clearer thought and increased strength as well as to activate the immune system to deal with potential injury and to repair potential wounds. When the perceived threat is removed, assuming no damage is done, the body returns to normal.

A cascade of endocrine hormones and cytokines are released when the brain signals a person is threatened with harm, injury, undue mental or physical stress or death. These proteins prepare the body to react quickly by increasing heart rate, making muscles more reactive, stimulating thought, altering sugar metabolism, and producing many more changes that result in the "rush" people experience when they think they may be harmed.

A team of researchers at Ohio State University Medical Center led by Doctor Janice Kiecolt-Glaser found that one particular immune system protein acts as a blood marker for measuring chronic stress and is linked to an impaired immune system response in aging adults. The team studied aging caregivers and found a four-fold increase in an immune system protein – interleukin 6 (IL-6) – as compared to an identically matched control group of non-caregivers.

The cascade of immune system proteins in the fight or flight reaction is mediated by IL-6, which takes the role of directing the immune system to gear up to prevent infection, promote wound healing and repair organs and muscles from any injury that may result from the imminent danger. The release of all of these cytokines such as IL-1, IL-6, IL-8, TNF and other proteins such as CRP (C reactive protein) also promote development of inflammation, which is essential for blood cells to home in on injury or infection. In addition, these chemicals promote development of various types of immune system blood cells in bone marrow. This response to harm – either real or perceived – is an important and beneficial life-saving activity of a normally functioning body.

In most younger people, when the threat lessens or disappears, the body reacts quickly to shut down the stress response and return things to normal. But numerous studies have shown, as people age, the chemical cascade from stress lingers. This is especially true when the stress response is triggered regularly over time. This is called chronic stress. Eventually, this constant chemical stimulus from chronic stress impairs the immune system and results in early aging, development of debilitating disease and early death. In this altered state, the body maintains high, potentially harmful levels of IL-6. The body does not return to normal without intervention.

Prolonged high levels of IL-6 and the accompanying hormones and cytokines have been linked to: cardiovascular disease, type II diabetes, frequent viral infections, intestinal problems, stomach and colon disorders, osteoporosis, periodontal disease, various cancers and auto immune disorders such as lupus, rheumatoid arthritis and multiple sclerosis. Alzheimer's, dementia, nerve damage and mental problems are also linked to high IL-6. Wounds heal slower, vaccinations are less likely to take and recovery from infectious disease is impaired. People who have depression also have high levels of IL-6. Depression in caregivers is about 8 times higher than the non-caregiving population.

This debilitating response to chronic stress is not unique to humans. Animals are affected as well. A 2004 PBS Scientific American Frontiers Special entitled "Worried Sick", explored the effect of chronic stress on animals. Observations in the field and experiments on animals exposed to chronic stress, uncovered the same phenomenon of debilitating disease and early death found in humans. Blood tests on the affected animals confirmed high levels of IL-6. The work of Dr. Janice Kiecolt-Glaser’s team was also followed in the Special.

The information above should provide a compelling reason to eliminate or reduce the stress experienced by aging seniors.